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Sample records for aggressively oxidizing environments

  1. Protection of Conductive and Non-conductive Advanced Polymer-based Paints from Highly Aggressive Oxidative Environments

    NASA Technical Reports Server (NTRS)

    Gudimenko, Y.; Ng, R.; Iskanderova, Z.; Kleiman, J.; Grigorevsky, A.; Kiseleva, L.; Finckenor, M.; Edwards, D.

    2005-01-01

    Research has been continued to further improve the space durability of conductive and non-conductive polymer-based paints and of conductive thermal control paints for space applications. Efforts have been made to enhance the space durability and stability of functional Characteristics in ground-based space environment imitating conditions, using specially developed surface modification treatment. The results of surface modification of new conductive paints, including the ground-based testing in aggressive oxidative environments, such as atomic oxygen/UV and oxygen plasma, and performance evaluation are presented. Functional properties and performance characteristics, such as thermal optical properties (differential solar absorptance and thermal emittance representing the thermal optical performance of thermal control paints) and surface resistivity characteristics of pristine, surface modified, and tested materials were verified. Extensive surface analysis studies have been performed using complementary surface analyses including SEM/EDS and XPS. Test results revealed that the successfully treated materials exhibit reduced mass loss and no surface morphology change, thus indicating good protection from the severe oxidative environment. It was demonstrated that the developed surface modification treatment could be applied successfully to charge dissipative and conductive paints.

  2. Socially responsive effects of brain oxidative metabolism on aggression

    PubMed Central

    Li-Byarlay, Hongmei; Rittschof, Clare C.; Massey, Jonathan H.; Pittendrigh, Barry R.; Robinson, Gene E.

    2014-01-01

    Despite ongoing high energetic demands, brains do not always use glucose and oxygen in a ratio that produces maximal ATP through oxidative phosphorylation. In some cases glucose consumption exceeds oxygen use despite adequate oxygen availability, a phenomenon known as aerobic glycolysis. Although metabolic plasticity seems essential for normal cognition, studying its functional significance has been challenging because few experimental systems link brain metabolic patterns to distinct behavioral states. Our recent transcriptomic analysis established a correlation between aggression and decreased whole-brain oxidative phosphorylation activity in the honey bee (Apis mellifera), suggesting that brain metabolic plasticity may modulate this naturally occurring behavior. Here we demonstrate that the relationship between brain metabolism and aggression is causal, conserved over evolutionary time, cell type-specific, and modulated by the social environment. Pharmacologically treating honey bees to inhibit complexes I or V in the oxidative phosphorylation pathway resulted in increased aggression. In addition, transgenic RNAi lines and genetic manipulation to knock down gene expression in complex I in fruit fly (Drosophila melanogaster) neurons resulted in increased aggression, but knockdown in glia had no effect. Finally, honey bee colony-level social manipulations that decrease individual aggression attenuated the effects of oxidative phosphorylation inhibition on aggression, demonstrating a specific effect of the social environment on brain function. Because decreased neuronal oxidative phosphorylation is usually associated with brain disease, these findings provide a powerful context for understanding brain metabolic plasticity and naturally occurring behavioral plasticity. PMID:25092297

  3. Effect of exposure delay of concrete into aggressive environment

    NASA Astrophysics Data System (ADS)

    Abimouloud, Youcef; Kriker, Abdelouahed

    2016-07-01

    Some regions in the world suffered since several years from environmental problems such as underground level water rising. Water table effects durability of concrete implantation in the underground by the ease of luckless chemical elements ingress mainly through concrete the foundations of structures such as sulfate, chloride, and acids. For that reason a lot of foundations structures were made with SRPC (sulfate resisting Portland cement). This study is a contribution to assess the effect of exposure delay of concrete into aggressive fields, as a kind of cure which protects concrete from aggressive factors and allows it to acquire the needed strength. The study has shown that concrete exposure delay into aggressive environment is not a kind of cure mainly for concrete made with SRPC. Concrete with SRPC immediately exposed to aggressive environment shows a better mechanical resistance than concrete that has known exposure delay.

  4. Tribology of engineered surfaces in aggressive environments

    NASA Astrophysics Data System (ADS)

    Mitchell, Nathan Phillip

    To improve the performance of sliding systems, surface modifications and coatings are often applied to opposing surfaces. This thesis focuses on characterizing two tribo-systems (DLC-DLC and steel micropatterns-flat) under their predicted application environments. The first section is focused on friction testing of micropatterned surfaces for orthopaedic device design, the second section elucidates how the sliding of diamond-like-carbon (DLC) coatings changes with temperature and humidity. The experimental design and major results of these sections are as follows. (1) The use of micropatterning to create uniform surface morphologies has been cited as yielding improvements in the coefficient of friction during high velocity sliding contact. Studies have not been preformed to determine if these micropatterns could also be useful in biomedical applications, such as total joint replacement surfaces, where the lower sliding velocities are used. In this study, the effect of pattern geometry, feature size and lubricant on contact friction and surface damage was investigated using 316L steel in sliding contact with a stainless steel and polyethylene pins. Using a novel proprietary forming process that creates millions of microstructures in parallel, a variety of micropatterned surfaces were fabricated to study the influence of shape (oval, circular, square), geometry (depressions, pillars) and feature size (10, 50 and 100 um) on both contact friction and surface damage. The coefficients of friction were measured for each surface/lubricant/pin system using a CETR scratch testing system. Results showed that round depressions with diameters of 10 μm had a significantly lower steady state coefficient of friction than the non-patterned substrates or substrates with greater diameter depression patterns. (2) The use of diamond-like carbon (DLC) has been cited as a friction and wear reducing coating during sliding contact and is widely used in the hard disk drive (HDD) industry

  5. Social Environments and Physical Aggression among 21,107 Students in the United States and Canada

    ERIC Educational Resources Information Center

    Pickett, William; Iannotti, Ronald J.; Simons-Morton, Bruce; Dostaler, Suzanne

    2009-01-01

    Background: Physical aggression is an important issue in North American populations. The importance of students' social environments in the occurrence of physical aggression requires focused study. In this study, reports of physical aggression were examined in relation to social environment factors among national samples of students from Canada…

  6. Gene-Environment Processes Linking Aggression, Peer Victimization, and the Teacher-Child Relationship

    ERIC Educational Resources Information Center

    Brendgen, Mara; Boivin, Michel; Dionne, Ginette; Barker, Edward D.; Vitaro, Frank; Girard, Alain; Tremblay, Richard; Perusse, Daniel

    2011-01-01

    Aggressive behavior in middle childhood is at least partly explained by genetic factors. Nevertheless, estimations of simple effects ignore possible gene-environment interactions (G x E) or gene-environment correlations (rGE) in the etiology of aggression. The present study aimed to simultaneously test for G x E and rGE processes between…

  7. Links between Friends' Physical Aggression and Adolescents' Physical Aggression: What Happens If Gene-Environment Correlations are Controlled?

    ERIC Educational Resources Information Center

    Vitaro, Frank; Brendgen, Mara; Girard, Alain; Dionne, Ginette; Tremblay, Richard E.; Boivin, Michel

    2016-01-01

    Exposure to deviant friends has been found to be a powerful source of influence on children's and adolescents' aggressive behavior. However, the contribution of deviant friends may have been overestimated because of a possible non-accounted gene-environment correlation (rGE). In this study, we used a cross-lagged design to test whether friends'…

  8. Elimination of aggressive behavior in male mice lacking endothelial nitric oxide synthase.

    PubMed

    Demas, G E; Kriegsfeld, L J; Blackshaw, S; Huang, P; Gammie, S C; Nelson, R J; Snyder, S H

    1999-10-01

    Male mice with targeted deletion of the gene encoding the neuronal isoform of nitric oxide synthase (nNOS(-/-)) display increased aggressive behavior compared with wild-type (WT) mice. Specific pharmacological inhibition of nNOS with 7-nitroindazole also augments aggressive behavior. We report here that male mice with targeted deletion of the gene encoding endothelial NOS (eNOS(-/-)) display dramatic reductions in aggression. The effects are selective, because an extensive battery of behavioral tests reveals no other deficits. In the resident-intruder model of aggression, resident eNOS(-/-) males show virtually no aggression. Latency for aggression onset is 25-30 times longer in eNOS(-/-) males compared with WT males in the rare instances of aggressive behaviors. Similarly, a striking lack of aggression is noted in tests of aggression among groups of four mice monitored in neutral cages. Although eNOS(-/-) mice are hypertensive ( approximately 14 mmHg blood pressure elevation), hypertension does not appear responsible for the diminished aggression. Reduction of hypertension with hydralazine does not change the prevalence of aggression in eNOS(-/-) mice. Extensive examination of brains from eNOS(-/-) male mice reveals no obvious neural damage from chronic hypertension. In situ hybridization in WT animals reveals eNOS mRNA in the brain associated exclusively with blood vessels and no neuronal localizations. Accordingly, vascular eNOS in the brain appears capable of influencing behavior with considerable selectivity. PMID:10493775

  9. Adolescent bystanders' perspectives of aggression in the online versus school environments.

    PubMed

    Patterson, Lisa J; Allan, Alfred; Cross, Donna

    2016-06-01

    Researchers' understanding of bystanders' perspectives in the cyber-environment fails to take young people's perceptions into account and remains imperfect. Interventions encouraging adolescents to help targets of cyber-aggression are therefore typically based upon traditional school-based aggression research. Twenty-four in-depth interviews with Australian 13-16 year-olds revealed two themes that reflect how young bystanders perceive differences between aggression online and at school. The physical presence theme suggests that young bystanders struggle to determine online intentions in the absence of body language, leading to hesitancy in reactions and furthermore make it easier for them to ignore online transgressions and avoid becoming involved. The authority theme indicates young bystanders perceive that, compared to the school environment, the online environment lacks clearly established rules, authority figures and formal reporting mechanisms. These differences indicate that unique strategies should be developed to encourage young bystanders to intervene in cyber-aggression situations. PMID:27007497

  10. Gene-environment correlation linking aggression and peer victimization: do classroom behavioral norms matter?

    PubMed

    Brendgen, Mara; Girard, Alain; Vitaro, Frank; Dionne, Ginette; Boivin, Michel

    2015-01-01

    Using a genetically informed design based on 197 Monozygotic and Dizygotic twin pairs assessed in grade 4, this study examined 1) whether, in line with a gene-environment correlation (rGE), a genetic disposition for physical aggression or relational aggression puts children at risk of being victimized by their classmates, and 2) whether this rGE is moderated by classroom injunctive norm salience in regard to physical or relational aggression. Physical aggression and relational aggression, as well as injunctive classroom norm salience in regard to these behaviors, were measured via peer nominations. Peer victimization was measured via self-reports. Multi-Level Mixed modeling revealed that children with a genetic disposition for either aggressive behavior are at higher risk of being victimized by their peers only when classroom norms are unfavourable toward such behaviors. However, when classroom injunctive norms favor aggressive behaviors, a genetic disposition for physical or relational aggression may actually protect children against peer victimization. These results lend further support to the notion that bullying interventions must include the larger peer context instead of a sole focus on victims and bullies. PMID:25723009

  11. Physical and verbal aggressive behavior and COMT genotype: Sensitivity to the environment.

    PubMed

    Tuvblad, Catherine; Narusyte, Jurgita; Comasco, Erika; Andershed, Henrik; Andershed, Anna-Karin; Colins, Olivier F; Fanti, Kostas A; Nilsson, Kent W

    2016-07-01

    Catechol-O-methyltransferase (COMT) genotype has been implicated as a vulnerability factor for several psychiatric diseases as well as aggressive behavior, either directly, or in interaction with an adverse environment. The present study aimed at investigating the susceptibility properties of COMT genotype to adverse and favorable environment in relation to physical and verbal aggressive behavior. The COMT Val158Met polymorphism was genotyped in a Swedish population-based cohort including 1,783 individuals, ages 20-24 years (47% males). A significant three-way interaction was found, after correction for multiple testing, between COMT genotype, exposure to violence, and parent-child relationship in association with physical but not verbal aggressive behavior. Homozygous for the Val allele reported lower levels of physical aggressive behavior when they were exposed to violence and at the same time experienced a positive parent-child relationship compared to Met carriers. Thus, susceptibility properties of COMT genotype were observed in relation to physical aggressive behavior supporting the hypothesis that COMT genotypes are modifying the sensitivity to environment that confers either risk or protection for aggressive behavior. As these are novel findings, they warrant further investigation and replication in independent samples. © 2016 Wiley Periodicals, Inc. PMID:26888414

  12. MAOA genotype, social exclusion and aggression: an experimental test of a gene-environment interaction.

    PubMed

    Gallardo-Pujol, D; Andrés-Pueyo, A; Maydeu-Olivares, A

    2013-02-01

    In 2002, Caspi and colleagues provided the first epidemiological evidence that genotype may moderate individuals' responses to environmental determinants. However, in a correlational study great care must be taken to ensure the proper estimation of the causal relationship. Here, a randomized experiment was performed to test the hypothesis that the MAOA gene promoter polymorphism (MAOA-LPR) interacts with environmental adversity in determining aggressive behavior using laboratory analogs of real-life conditions. A sample of 57 Caucasian male students of Catalan and Spanish origin was recruited at the University of Barcelona. Ostracism, or social exclusion, was induced as environmental adversity using the Cyberball software. Laboratory aggression was assessed with the Point Subtraction Aggression Paradigm (PSAP), which was used as an analog of antisocial behavior. We also measured aggressiveness by means of the reduced version of the Aggression Questionnaire. The MAOA-LPR polymorphism showed a significant effect on the number of aggressive responses in the PSAP (F(1,53) = 4.63, P = 0.03, partial η(2) = 0.08), as well as social exclusion (F(1,53) = 8.03, P = 0.01, partial η(2) = 0.13). Most notably, however, we found that the MAOA-LPR polymorphism interacts significantly with social exclusion in order to provoke aggressive behavior (F(1,53) = 4.42, P = 0.04, partial η(2) = 0.08), remarkably, the low-activity allele of the MAOA-LPR polymorphism carriers in the ostracized group show significantly higher aggression scores than the rest. Our results support the notion that gene-environment interactions can be successfully reproduced within a laboratory using analogs and an appropriate design. We provide guidelines to test gene-environment interactions hypotheses under controlled, experimental settings. PMID:23067570

  13. Boron nitride coatings and materials for use in aggressive environments

    SciTech Connect

    Besmann, T.M.; Lee, W.Y.; Young, J.P.; Xiao, H.

    1997-12-31

    Boron nitride coatings and structures have demonstrated significant resistance to many corrosive environments. These coatings may have application in the protection of sensors needed for measuring a variety of properties such as temperature and chemistry. In addition, boron nitride materials may offer advantages as structural materials in high temperature materials processing. In this study, BN is assessed for use in aluminum smelting.

  14. Playing to an audience: the social environment influences aggression and victory displays

    PubMed Central

    Fitzsimmons, Lauren P.; Bertram, Susan M.

    2013-01-01

    Animal behaviour studies have begun to incorporate the influence of the social environment, providing new opportunities for studying signal strategies and evolution. We examined how the presence and sex of an audience influenced aggression and victory display behaviour in field-captured and laboratory-reared field crickets (Gryllus veletis). Audience type, rearing environment and their interaction were important predictors in all model sets. Thus, audience type may impose different costs and benefits for competing males depending on whether they are socially experienced or not. Our results suggest that field-captured winners, in particular, dynamically adjust their contest behaviour to potentially gain a reproductive benefit via female eavesdropping and may deter future aggression from rivals by advertising their aggressiveness and victories. PMID:23843219

  15. Playing to an audience: the social environment influences aggression and victory displays.

    PubMed

    Fitzsimmons, Lauren P; Bertram, Susan M

    2013-08-23

    Animal behaviour studies have begun to incorporate the influence of the social environment, providing new opportunities for studying signal strategies and evolution. We examined how the presence and sex of an audience influenced aggression and victory display behaviour in field-captured and laboratory-reared field crickets (Gryllus veletis). Audience type, rearing environment and their interaction were important predictors in all model sets. Thus, audience type may impose different costs and benefits for competing males depending on whether they are socially experienced or not. Our results suggest that field-captured winners, in particular, dynamically adjust their contest behaviour to potentially gain a reproductive benefit via female eavesdropping and may deter future aggression from rivals by advertising their aggressiveness and victories. PMID:23843219

  16. Developmental Differences in Early Adolescent Aggression: A Gene × Environment × Intervention Analysis

    PubMed Central

    Cleveland, H. Harrington; Vandenbergh, David J.; Feinberg, Mark E.; Neiderhiser, Jenae M.; Greenberg, Mark T.; Spoth, Richard; Redmond, Cleve

    2015-01-01

    Aggression-related problems such as assault and homicide among adolescents and young adults exact considerable social and economic costs. Although progress has been made, additional research is needed to help combat this persistent problem. Several lines of research indicate that parental hostility is an especially potent predictor of adolescent aggression, although most longitudinal research has focused on clarifying the direction of effects. In this study, we used longitudinal data from the PROSPER project (N = 580; 54.8 % female), a primarily rural Caucasian preventative intervention sample, to examine developmental change in early- to mid-adolescent aggressive behavior problems (age 11–16 years). In addition, we examined maternal hostility as a predictor of developmental change in aggression and the PROSPER preventative intervention, designed to reduce substance use and aggression, as a potential influence on this association. Lastly, several studies indicate that variation in the DRD4 7-repeat gene moderates both parenting and intervention influences on externalizing behavior. Accordingly, we examined the potential moderating role of DRD4. As hypothesized, there was a significant maternal hostility by intervention interaction indicating that the intervention reduced the negative impact of maternal hostility on adolescent change in aggressive behavior problems. DRD4 7-repeat status (7+ vs. 7−) further conditioned this association whereby control group 7+ adolescents with hostile mothers showed increasing aggressive behavior problems. In contrast, aggression decreased for 7+ adolescents with similarly hostile mothers in the intervention. Implications for prevention are discussed as well as current perspectives in candidate gene-by-environment interaction research. PMID:25319639

  17. Aggression in Primary Schools: The Predictive Power of the School and Home Environment

    ERIC Educational Resources Information Center

    Kozina, Ana

    2015-01-01

    In this study, we analyse the predictive power of home and school environment-related factors for determining pupils' aggression. The multiple regression analyses are performed for fourth- and eighth-grade pupils based on the Trends in Mathematics and Science Study (TIMSS) 2007 (N = 8394) and TIMSS 2011 (N = 9415) databases for Slovenia. At…

  18. Examining Holland's Person-Environment Fit, Workplace Aggression, Interpersonal Conflict, and Job Satisfaction

    ERIC Educational Resources Information Center

    Pseekos, A. Chantelle; Bullock-Yowell, Emily; Dahlen, Eric R.

    2011-01-01

    The researchers examined the impact of person-environment (P-E) fit, as defined by Holland's (1997) theory, on interpersonal conflict at work (ICAW) and workplace aggression. In addition, previous relationships found in the job satisfaction literature were examined in the present sample of 244 United States employees. Internet-based surveys were…

  19. Aggressive and Violent Behaviors in the School Environment among a Nationally Representative Sample of Adolescent Youth

    ERIC Educational Resources Information Center

    Rajan, Sonali; Namdar, Rachel; Ruggles, Kelly V.

    2015-01-01

    Background: The purpose of this study was to describe the prevalence of aggressive and violent behaviors in the context of the school environment in a nationally representative sample of adolescent youth and to illustrate these patterns during 2001-2011. Methods: We analyzed data from 84,734 participants via the Youth Risk Behavior Surveillance…

  20. Frequency stabilization of laser diodes in an aggressive thermal environment

    NASA Astrophysics Data System (ADS)

    Minch, J. R.; Walther, F. G.; Savage, S.; Plante, A.; Scalesse, V.

    2015-03-01

    Mobile free-space laser communication systems must reconcile the requirements of low size, weight, and power with the ability to both survive and operate in harsh thermal and mechanical environments. In order to minimize the aperture size and amplifier power requirements of such systems, communication links must exhibit performance near theoretical limits. Such performance requires laser transmitters and receiver filters and interferometers to maintain frequency accuracy to within a couple hundred MHz of the design frequency. We demonstrate an approach to achieving high frequency stability over wide temperature ranges by using conventional DFB lasers, tuned with TEC and current settings, referenced to an HCN molecular frequency standard. A HCN cell absorption line is scanned across the TEC set-point to adjust the DFB laser frequency. Once the center of the line is determined, the TEC set-point is offset as required to obtain frequency agility. To obtain large frequency offsets from an HCN absorption line, as well as continuous laser source operation, a second laser is offset from the reference laser and the resulting beat tone is detected in a photoreceiver and set to the desired offset using a digital frequency-locked loop. Using this arrangement we have demonstrated frequency accuracy and stability of better than 8 MHz RMS over an operational temperature range of 0ºC to 50º C, with operation within minutes following 8 hour soaks at -40º C and 70º C.

  1. Coho Salmon (Oncorhynchus kisutch) Prefer and Are Less Aggressive in Darker Environments

    PubMed Central

    Gaffney, Leigh P.; Franks, Becca; Weary, Daniel M.; von Keyserlingk, Marina A. G.

    2016-01-01

    Fish are capable of excellent vision and can be profoundly influenced by the visual properties of their environment. Ambient colours have been found to affect growth, survival, aggression and reproduction, but the effect of background darkness (i.e., the darkness vs. lightness of the background) on preference and aggression has not been evaluated systematically. One-hundred Coho salmon (Oncorhynchus kisutch), a species that is increasing in popularity in aquaculture, were randomly assigned to 10 tanks. Using a Latin-square design, every tank was bisected to allow fish in each tank to choose between all the following colour choices (8 choices in total): black vs. white, light grey, dark grey, and a mixed dark grey/black pattern, as well as industry-standard blue vs. white, light grey, dark grey, and black. Fish showed a strong preference for black backgrounds over all other options (p < 0.01). Across tests, preference strength increased with background darkness (p < 0.0001). Moreover, having darker backgrounds in the environment resulted in less aggressive behaviour throughout the tank (p < 0.0001). These results provide the first evidence that darker tanks are preferred by and decrease aggression in salmonids, which points to the welfare benefits of housing farmed salmon in enclosures containing dark backgrounds. PMID:27028731

  2. Coho Salmon (Oncorhynchus kisutch) Prefer and Are Less Aggressive in Darker Environments.

    PubMed

    Gaffney, Leigh P; Franks, Becca; Weary, Daniel M; von Keyserlingk, Marina A G

    2016-01-01

    Fish are capable of excellent vision and can be profoundly influenced by the visual properties of their environment. Ambient colours have been found to affect growth, survival, aggression and reproduction, but the effect of background darkness (i.e., the darkness vs. lightness of the background) on preference and aggression has not been evaluated systematically. One-hundred Coho salmon (Oncorhynchus kisutch), a species that is increasing in popularity in aquaculture, were randomly assigned to 10 tanks. Using a Latin-square design, every tank was bisected to allow fish in each tank to choose between all the following colour choices (8 choices in total): black vs. white, light grey, dark grey, and a mixed dark grey/black pattern, as well as industry-standard blue vs. white, light grey, dark grey, and black. Fish showed a strong preference for black backgrounds over all other options (p < 0.01). Across tests, preference strength increased with background darkness (p < 0.0001). Moreover, having darker backgrounds in the environment resulted in less aggressive behaviour throughout the tank (p < 0.0001). These results provide the first evidence that darker tanks are preferred by and decrease aggression in salmonids, which points to the welfare benefits of housing farmed salmon in enclosures containing dark backgrounds. PMID:27028731

  3. The Effects of Aggressive Environments on the Properties of Fly Ash based Geopolymers

    NASA Astrophysics Data System (ADS)

    Baščarević, Z.; Komljenović, M.; Nikolić, V.; Marjanović, N.

    2015-11-01

    This paper analyzes the effects of two different aggressive environments, concentrated ammonium nitrate solution (480 g/dm3) and sodium sulphate solution (50 g/dm3), on the structure and mechanical strength of fly ash based geopolymers. Geopolymer samples were subjected to the aggressive solutions over a period of 365 days. It was found that exposure to the NH4NO3 and Na2SO4 solutions caused small decrease in geopolymer strength (10-20%). The most valuable insight into the structural changes caused by testing of the geopolymer samples in the aggressive solutions was provided by means of 29Si MAS NMR. It was found that the immersion of geopolymer samples in the NH4NO3 solution caused breaking of Si-O-Al bonds in the aluminosilicate geopolymer gel structure. On the other hand, treatment of the geopolymer samples with the Na2SO4 solution resulted in breaking of Si-O-Si bonds in geopolymer gel structure and leaching of Si. It was concluded that the major changes in the geopolymer structure were associated with the changes in the pH values of aggressive solutions during the testing.

  4. Production, fabrication, and performance of alloy 625 clad steel for aggressive corrosive environments

    SciTech Connect

    Stevens, C.E.; Ross, R.W. Jr.

    1986-06-01

    INCONEL/sup */ alloy 625 is a nickel-chromium-molybdenum-columbium alloy used in aggressive corrosive applications where high strength, fabricability, and outstanding corrosion resistance are required. Because of these properties, the alloy is used by the power and chemical industries in a variety of components in coal-fired, nuclear, and chemical process plants. However, widespread use of INCONEL alloy 625 is limited due to its cost. There is a need, notably in utility flue gas desulfurization systems (scrubbers) for an economical, highly corrosive-resistant material. To satisfy this need, INCONEL alloy 625 thin-gauge clad steel plate was developed by Lukens Steel Company. The corrosion resistance of INCONEL alloy 625 in several aggressive corrosive environments will be reviewed. Additionally, this paper will describe methods used to manufacture, fabricate, and weld INCONEL alloy 625 clad plate. Field test evaluation programs conducted at six power plant scrubber systems will also be reported.

  5. Interactions between Biliverdin, Oxidative Damage, and Spleen Morphology after Simulated Aggressive Encounters in Veiled Chameleons

    PubMed Central

    Butler, Michael W.; Ligon, Russell A.

    2015-01-01

    Stressors frequently increase oxidative damage–unless organisms simultaneously mount effective antioxidant responses. One putative mitigative mechanism is the use of biliverdin, an antioxidant produced in the spleen during erythrocyte degradation. We hypothesized that both wild and captive-bred male veiled chameleons (Chamaeleo calyptratus), which are highly aggressive to conspecifics, would respond to agonistic displays with increased levels of oxidative damage, but that increased levels of biliverdin would limit this increase. We found that even just visual exposure to a potential combatant resulted in decreased body mass during the subsequent 48-hour period, but that hematocrit, biliverdin concentration in the bile, relative spleen size, and oxidative damage in plasma, liver, and spleen were unaffected. Contrary to our predictions, we found that individuals with smaller spleens exhibited greater decreases in hematocrit and higher bile biliverdin concentrations, suggesting a revision to the idea of spleen-dependent erythrocyte processing. Interestingly, individuals with larger spleens had reduced oxidative damage in both the liver and spleen, demonstrating the spleen’s importance in modulating oxidative damage. We also uncovered differences in spleen size and oxidative damage between wild and captive-bred chameleons, highlighting environmentally dependent differences in oxidative physiology. Lastly, we found no relationship between oxidative damage and biliverdin concentration, calling into question biliverdin’s antioxidant role in this species. PMID:26368930

  6. Evaluation of the stability of polypropylene fibers in environments aggressive to cement-based materials

    SciTech Connect

    Segre, N.; Tonella, E.; Joekes, I.

    1998-01-01

    Isotactic polypropylene (PPi) fibers were left in NaOH, H{sub 2}SO{sub 4}, synthetic seawater, and cement-with-water solutions at different temperatures and exposure times. Infrared microspectroscopy was used to follow the formation of degradation products. Cement-with-water was the most aggressive bath for the fibers, causing marked oxidation after 100 days exposure; also, the molecular weight of PPi increased as determined by viscosimetry. Mortar test specimens containing PPi fibers and exposed to CO{sub 2}, synthetic seawater, and MgSO{sub 4} 0.25 M showed a decrease in compressive strength after 260 days. The compressive strength of mortar test specimens containing 0.75 kg/m{sup 3} of PPi fibers irradiated with ultraviolet radiation was roughly 10% lower than that of the control specimen, after only 60 days in water.

  7. Childhood trauma and parental style: Relationship with markers of inflammation, oxidative stress, and aggression in healthy and personality disordered subjects.

    PubMed

    Fanning, Jennifer R; Lee, Royce; Gozal, David; Coussons-Read, Mary; Coccaro, Emil F

    2015-12-01

    Recent studies suggest that early life trauma is associated with elevations in circulating markers of inflammation in human subjects. History of aggression as a behavior, or aggression as a personality trait, is also associated with elevations of these inflammatory markers. Since early life trauma is associated with the development and maintenance of aggression in later life we examined the relationship of early life adversity, plasma inflammation markers (IL-6 and CRP) and oxidative stress markers (8-OH-DG and 8-ISO), and aggression in adult subjects with (n=79) and without (n=55) personality disorder. We used a series of mediated and moderated path models to test whether the effects of early adversity on later aggression may be mediated through markers of inflammation. Childhood abuse and parental control were associated with basal IL-6 and CRP concentrations. Path modeling suggested that childhood abuse was associated with aggression indirectly through CRP while parental control influenced aggression indirectly through IL-6 and CRP. Furthermore, these effects were independent of the effect of current depression. The results suggest that disruption of inflammatory processes represent one pathway by which early adversity influences aggression. PMID:26423894

  8. EMAA thermoplastic powder coatings: Shop and field application of powder coatings for aggressive environments

    SciTech Connect

    Loustaunau, P.J.; Horton, D.

    1994-12-31

    This paper deals with how Ethylene Methacrylic Acid thermoplastic powder coatings are allowing asset owners to meet tightening environmental regulations while solving some of their most difficult coating problems. It discusses the versatility of traditional shop application methods and field application/repair methods in the rail and water/waste water treatment areas. EMAA coatings typically perform well in aggressive environments due to their high flexibility and impact resistance. The material`s inherent toughness also provides for excellent abrasion resistance. EMAA demonstrates excellent resistance to chemical attack and is highly resistant to permeation by liquids. Because some aromatic, cyclic and higher aliphatic hydrocarbon solvents may cause swelling and permeate through the coating, caution should be used in immersion applications with this group of solutions.

  9. Iridium material for hydrothermal oxidation environments

    DOEpatents

    Hong, Glenn T.; Zilberstein, Vladimir A.

    1996-01-01

    A process for hydrothermal oxidation of combustible materials in which, during at least a part of the oxidation, corrosive material is present and makes contact with at least a portion of the apparatus over a contact area on the apparatus. At least a portion of the contact surface area comprises iridium, iridium oxide, an iridium alloy, or a base metal overlaid with an iridium coating. Iridium has been found to be highly resistant to environments encountered in the process of hydrothermal oxidation. Such environments typically contain greater than 50 mole percent water, together with oxygen, carbon dioxide, and a wide range of acids, bases and salts. Pressures are typically about 27.5 to about 1000 bar while temperatures range as high as 800.degree. C.

  10. Aggression between siblings: Associations with the home environment and peer bullying.

    PubMed

    Tippett, Neil; Wolke, Dieter

    2014-09-01

    Sibling aggression is a common form of intra-familial aggression, yet has been largely neglected by research. Using an inclusive measure of sibling aggression, this study investigated, firstly, prevalence of sibling aggression and associations with family and household characteristics, and secondly, the relationship between sibling aggression and peer bullying. Participants were 4,237 adolescents from Wave 1 of Understanding Society. Four types of sibling aggression were measured: physical, verbal, stealing and teasing, and combined into composite measures of victimization and perpetration. Regression analysis identified associations with demographic characteristics, family and sibling composition, parent-child relationships and socioeconomic status and explored the link between sibling aggression and involvement in peer bullying. Using a broad definition, sibling aggression was found to be widespread, with 46% of all participants being victimized and 36% perpetrating aggression. Household and family characteristics, including a large family size, male siblings, and financial difficulties were associated with greater rates of sibling aggression. Parenting behavior showed the strongest relationship: harsh parenting increased the risk of sibling aggression while positive parenting protected against it. Sibling aggression was also homotypically related to involvement in peer bullying. Victimization by siblings significantly increased the odds of being a victim of peer bullying, and perpetrators of sibling aggression were more likely to be both peer bullies and bully-victims. Considering the adverse effects of sibling aggression on physical and mental health, the study provides pointers for efforts to reduce the risk of sibling aggression. Furthermore, the link with peer bullying suggests that school anti-bullying efforts should also take account of children's sibling relationships. Aggr. Behav. 9999:XX-XX, 2014. © 2014 Wiley Periodicals, Inc. PMID:25187483

  11. Developmental differences in early adolescent aggression: a gene × environment × intervention analysis.

    PubMed

    Schlomer, Gabriel L; Cleveland, H Harrington; Vandenbergh, David J; Feinberg, Mark E; Neiderhiser, Jenae M; Greenberg, Mark T; Spoth, Richard; Redmond, Cleve

    2015-03-01

    Aggression-related problems such as assault and homicide among adolescents and young adults exact considerable social and economic costs. Although progress has been made, additional research is needed to help combat this persistent problem. Several lines of research indicate that parental hostility is an especially potent predictor of adolescent aggression, although most longitudinal research has focused on clarifying the direction of effects. In this study, we used longitudinal data from the PROSPER project (N = 580; 54.8% female), a primarily rural Caucasian preventative intervention sample, to examine developmental change in early- to mid-adolescent aggressive behavior problems (age 11-16 years). In addition, we examined maternal hostility as a predictor of developmental change in aggression and the PROSPER preventative intervention, designed to reduce substance use and aggression, as a potential influence on this association. Lastly, several studies indicate that variation in the DRD4 7-repeat gene moderates both parenting and intervention influences on externalizing behavior. Accordingly, we examined the potential moderating role of DRD4. As hypothesized, there was a significant maternal hostility by intervention interaction indicating that the intervention reduced the negative impact of maternal hostility on adolescent change in aggressive behavior problems. DRD4 7-repeat status (7+ vs. 7-) further conditioned this association whereby control group 7+ adolescents with hostile mothers showed increasing aggressive behavior problems. In contrast, aggression decreased for 7+ adolescents with similarly hostile mothers in the intervention. Implications for prevention are discussed as well as current perspectives in candidate gene-by-environment interaction research. PMID:25319639

  12. Ceramic coating system or water oxidation environments

    DOEpatents

    Hong, Glenn T.

    1996-01-01

    A process for water oxidation of combustible materials in which during at least a part of the oxidation corrosive material is present and makes contact with at least a portion of the apparatus over a contact area on the apparatus. At least a portion of the contact surface area comprises titanium dioxide coated onto a titanium metal substrate. Such ceramic composites have been found to be highly resistant to environments encountered in the process of supercritical water oxidation. Such environments typically contain greater than 50 mole percent water, together with oxygen, carbon dioxide, and a wide range of acids, bases, and salts. Pressures are typically about 27.5 to about 1000 bar while temperatures range as high as 700.degree. C. The ceramic composites are also resistant to degradation mechanisms caused by thermal stresses.

  13. Ceramic coating system for water oxidation environments

    SciTech Connect

    Hong, G.T.

    1996-08-13

    A process is described for water oxidation of combustible materials in which at least a part of the oxidation corrosive material is present and makes contact with at least a portion of the apparatus over a contact area on the apparatus. At least a portion of the contact surface area comprises titanium dioxide coated onto a titanium metal substrate. Such ceramic composites have been found to be highly resistant to environments encountered in the process of supercritical water oxidation. Such environments typically contain greater than 50 mole percent water, together with oxygen, carbon dioxide, and a wide range of acids, bases, and salts. Pressures are typically about 27.5 to about 1000 bar while temperatures range as high as 700 C. The ceramic composites are also resistant to degradation mechanisms caused by thermal stresses. 2 figs.

  14. Influence of aggressive ions on the degradation behavior of biomedical magnesium alloy in physiological environment.

    PubMed

    Xin, Yunchang; Huo, Kaifu; Tao, Hu; Tang, Guoyi; Chu, Paul K

    2008-11-01

    Various electrochemical approaches, including potentiodynamic polarization, open circuit potential evolution and electrochemical impedance spectroscopy (EIS), are employed to investigate the degradation behavior of biomedical magnesium alloy under the influence of aggressive ions, such as chloride, phosphate, carbonate and sulfate, in a physiological environment. The synergetic effects and mutual influence of these ions on the degradation behavior of Mg are revealed. Our results demonstrate that chloride ions can induce porous pitting corrosion. In the presence of phosphates, the corrosion rate decreases and the formation of pitting corrosion is significantly delayed due to precipitation of magnesium phosphate. Hydrogen carbonate ions are observed to stimulate the corrosion of magnesium alloy during the early immersion stage but they can also induce rapid passivation on the surface. This surface passivation behavior mainly results from the fast precipitation of magnesium carbonate in the corrosion product layer that can subsequently inhibit pitting corrosion completely. Sulfate ions are also found to stimulate magnesium dissolution. These results improve our understanding on the degradation mechanism of surgical magnesium in the physiological environment. PMID:18571486

  15. Teacher and Staff Perceptions of School Environment as Predictors of Student Aggression, Victimization, and Willingness to Intervene in Bullying Situations

    ERIC Educational Resources Information Center

    Espelage, Dorothy L.; Polanin, Joshua R.; Low, Sabina K.

    2014-01-01

    This study examines how teacher and staff perceptions of the school environment correlate with student self-reports of bullying, aggression, victimization, and willingness to intervene in bullying incidents using multi-informant, multilevel modeling. Data were derived from 3,616 6th grade students across 36 middle schools in the Midwest, who…

  16. The Role of the School Environment in Relational Aggression and Victimization

    ERIC Educational Resources Information Center

    Elsaesser, Caitlin; Gorman-Smith, Deborah; Henry, David

    2013-01-01

    Research conducted over the last decade has documented both the high rates of and serious consequences associated with both victimization and perpetration of relational aggression. This study examines risk for involvement in relational aggression and victimization among middle school youth, evaluating both individual beliefs about violence, as…

  17. Television Violence and Aggression: A Genotype-Environment Correlation and Interaction Theory.

    ERIC Educational Resources Information Center

    Lynn, Richard; And Others

    1989-01-01

    Examined relationships among aggression, viewing and enjoyment of television violence, and personality traits of extraversion, neuroticism, and psychoticism in sibling pairs (N=386) ages 11 to 16. Found no support for theory of causal effect on amount of viewing television violence on aggression. Found no within family correlations between amount…

  18. The Behavior of Environmentally Friendly Corrosion Preventative Compounds in an Aggressive Coastal Marine Environment

    NASA Technical Reports Server (NTRS)

    Montgomery, Eliza L.; Calle, Luz Marina; Curran Jerome C.; Kolody, Mark R.

    2013-01-01

    The shift to use environmentally friendly technologies throughout future space-related launch programs prompted a study aimed at replacing current petroleum and solvent-based Corrosion Preventive Compounds (CPCs) with environmentally friendly alternatives. The work in this paper focused on the identification and evaluation of environmentally friendly CPCs for use in protecting flight hardware and ground support equipment from atmospheric corrosion. The CPCs, while a temporary protective coating, must survive in the aggressive coastal marine environment that exists throughout the Kennedy Space Center, Florida. The different protection behaviors of fifteen different soft film CPCs, both common petroleum-based and newer environmentally friendly types, were evaluated on various steel and aluminum substrates. The CPC and substrate systems were subjected to atmospheric testing at the Kennedy Space Center's Beachside Atmospheric Corrosion Test Site, as well as cyclic accelerated corrosion testing. Each CPC also underwent physical characterization and launch-related compatibility testing . The initial results for the fifteen CPC systems are reported : Key words: corrosion preventive compound, CPC, spaceport, environmentally friendly, atmospheric exposure, marine, carbon steel, aluminum alloy, galvanic corrosion, wire on bolt.

  19. [Cellular defense system of some synanthropic dipterans inhabitant of bacterially aggressive environment].

    PubMed

    Kind, T V

    2014-01-01

    The hemocytic count and defense reaction within 4 families of higher Diptera: Tabanidae, Syrphidae, Muscidae and Sarcophagidae, whose larvae inhabit bacterially aggressive environment, were investigated. The least hemocytes types (3) were revealed in Tabanidae and Syrphidae larvae--prohemocytes, plasmatocytes and prophenoloxydase-containing unstable hyaline cells (oenocytoids). In Sarcophaga crassipalpis and Musca domestica stable hyaline cells and thrombocytoids or podocytoid-like cells can be added to this set. At the time of pupariation in Sarcophaga, new generation of prohemocytes is segregated into the hemolymph, which form small round or spindle-shaped hyaline cells. So, the number of plasmatocyte types in Sarcophaga increase to six. Typical to Calliphoridae juvenile plasmatocytes in the members of investigated families are absent. Among the one hemocyte type morphology also can vary, especially in unstable prophenoloxydase hyaline cells. In Drosophila there are crystal cells containing in the cytoplasm paracrystalloidal inclusions. In Calliphoridae there are big hyaline cells with homogenous cytoplasm producing circumferential bubbles. Both in Sarcophaga and Tabanidae they contain in their cytoplasm big globules. However in Sarcophaga they rapidly disintegrate, while in Tabanidae are maintained unchanged during hours. In Muscidae and Syrphidae prophenoloxydase extrusion occurs very early and these cells obtain pycnotic nuclei and very liquid cytoplasm with strings of granules. Thrombocytoids in Musca larvae are represented by big flattened anucleated irregular cytoplasm and "naked" nuclei and cytoplasmic fragments often with fan-like projections. Plasmatocytes in all species studied are the cells with pronounced phylopodies. In larvae they contain cytoplasmic catabolic inclusions and in pupa--ragments of apoptotic tissues. Clearance of hemolymph from alien particles in Sarcophagidae and Muscidae occur by thrombocytoides, while in Tabanidae by plasmatocyte

  20. Rigorous tests of gene-environment interactions in a lab study of the oxytocin receptor gene (OXTR), alcohol exposure, and aggression.

    PubMed

    LoParo, Devon; Johansson, Ada; Walum, Hasse; Westberg, Lars; Santtila, Pekka; Waldman, Irwin

    2016-07-01

    Naturalistic studies of gene-environment interactions (G X E) have been plagued by several limitations, including difficulty isolating specific environmental risk factors from other correlated aspects of the environment, gene-environment correlation (rGE ), and the use of a single genetic variant to represent the influence of a gene. We present results from 235 Finnish young men in two lab studies of aggression and alcohol challenge that attempt to redress these limitations of the extant G X E literature. Specifically, we use a latent variable modeling approach in an attempt to more fully account for genetic variation across the oxytocin receptor gene (OXTR) and to robustly test its main effects on aggression and its interaction with alcohol exposure. We also modeled aggression as a latent variable comprising various indices, including the average and maximum levels of aggression, the earliest trial on which aggression was expressed, and the proportion of trials on which the minimum and maximum levels of aggression were expressed. The best fitting model for the genetic variation across OXTR included six factors derived from an exploratory factor analysis, roughly corresponding to six haplotype blocks. Aggression levels were higher on trials in which participants were administered alcohol, won, or were provoked. There was a significant main effect of OXTR on aggression across studies after controlling for covariates. The interaction of OXTR and alcohol was also significant across studies, such that OXTR had stronger effects on aggression in the alcohol administration condition. © 2015 Wiley Periodicals, Inc. PMID:26250573

  1. Innovative Approach to Establish Root Causes for Cracking in Aggressive Reactor Environments

    SciTech Connect

    Bruemmer, Stephen M.; Thomas, Larry E.; Vetrano, John S.; Simonen, Edward P.

    2003-10-31

    The research focuses on the high-resolution characterization of degradation microstructures and microchemistries in specimens tested under controlled conditions for the environment and for the material where in-service complexities can be minimized. Thermodynamic and kinetic modeling of crack-tip processes is employed to analyze corrosion-induced structures and gain insights into degradation mechanisms. Novel mechanistic ''fingerprinting'' of crack-tip structures is used to isolate causes of environmental cracking in tandem with quantitative measurements of crack growth. Sample preparation methods and advanced analytical techniques are used to characterize corrosion/oxidation reactions and crack-tip structures at near atomic dimensions in order to gain insight into fundamental environmental cracking mechanisms. Reactions at buried interfaces, not accessible by conventional approaches, are being systematically interrogated. Crack-growth experiments in high-temperature water environments are evaluating and isolating the effects of material condition (matrix strength, grain boundary composition and precipitation) on stress corrosion cracking (SCC). The fundamental understanding of crack advance mechanisms will establish the basis to design new corrosion-resistant alloys for current light-water reactors and advanced reactor systems.

  2. Photocatalytic oxide films in the built environment

    NASA Astrophysics Data System (ADS)

    Österlund, Lars; Topalian, Zareh

    2014-11-01

    The possibility to increase human comfort in buildings is a powerful driving force for the introduction of new technology. Among other things our sense of comfort depends on air quality, temperature, lighting level, and the possibility of having visual contact between indoors and outdoors. Indeed there is an intimate connection between energy, comfort, and health issues in the built environment, leading to a need for intelligent building materials and green architecture. Photocatalytic materials can be applied as coatings, filters, and be embedded in building materials to provide self-cleaning, antibacterial, air cleaning, deodorizing, and water cleaning functions utilizing either solar light or artificial illumination sources - either already present in buildings, or by purposefully designed luminaries. Huge improvements in indoor comfort can thus be made, and also alleviate negative health effects associated with buildings, such as the sick-house syndrome. At the same time huge cost savings can be made by reducing maintenance costs. Photocatalytic oxides can be chemically modified by changing their acid-base surface properties, which can be used to overcome deactivation problems commonly encountered for TiO2 in air cleaning applications. In addition, the wetting properties of oxides can be tailored by surface chemical modifications and thus be made e.g. oleophobic and water repellent. Here we show results of surface acid modified TiO2 coatings on various substrates by means of photo-fixation of surface sulfate species by a method invented in our group. In particular, we show that such surface treatments of photocatalytic concrete made by mixing TiO2 nanoparticles in reactive concrete powders result in concrete surfaces with beneficial self-cleaning properties. We propose that such approaches are feasible for a number of applications in the built environment, including glass, tiles, sheet metals, plastics, etc.

  3. Understanding Fundamental Material Degradation Processes in High Temperature Aggressive Chemomechanical Environments

    SciTech Connect

    Stubbins, James; Gewirth, Andrew; Sehitoglu, Huseyin; Sofronis, Petros; Robertson, Ian

    2014-01-16

    The objective of this project is to develop a fundamental understanding of the mechanisms that limit materials durability for very high-temperature applications. Current design limitations are based on material strength and corrosion resistance. This project will characterize the interactions of high-temperature creep, fatigue, and environmental attack in structural metallic alloys of interest for the very high-temperature gas-cooled reactor (VHTR) or Next–Generation Nuclear Plant (NGNP) and for the associated thermo-chemical processing systems for hydrogen generation. Each of these degradation processes presents a major materials design challenge on its own, but in combination, they can act synergistically to rapidly degrade materials and limit component lives. This research and development effort will provide experimental results to characterize creep-fatigue-environment interactions and develop predictive models to define operation limits for high-temperature structural material applications. Researchers will study individually and in combination creep-fatigue-environmental attack processes in Alloys 617, 230, and 800H, as well as in an advanced Ni-Cr oxide dispersion strengthened steel (ODS) system. For comparison, the study will also examine basic degradation processes in nichrome (Ni-20Cr), which is a basis for most high-temperature structural materials, as well as many of the superalloys. These materials are selected to represent primary candidate alloys, one advanced developmental alloy that may have superior high-temperature durability, and one model system on which basic performance and modeling efforts can be based. The research program is presented in four parts, which all complement each other. The first three are primarily experimental in nature, and the last will tie the work together in a coordinated modeling effort. The sections are (1) dynamic creep-fatigue-environment process, (2) subcritical crack processes, (3) dynamic corrosion – crack

  4. Teacher and staff perceptions of school environment as predictors of student aggression, victimization, and willingness to intervene in bullying situations.

    PubMed

    Espelage, Dorothy L; Polanin, Joshua R; Low, Sabina K

    2014-09-01

    This study examines how teacher and staff perceptions of the school environment correlate with student self-reports of bullying, aggression, victimization, and willingness to intervene in bullying incidents using multi-informant, multilevel modeling. Data were derived from 3,616 6th grade students across 36 middle schools in the Midwest, who completed survey measures of bullying, aggression, victimization, and willingness to intervene in bullying situations. Teachers and staff (n = 1,447) completed a school environment survey. Bivariate associations between school-level and student self-reports indicated that as teacher and staff perceive aggression as a problem in their school, students reported greater bully perpetration, fighting, peer victimization, and less willingness to intervene. Further, as staff and teacher report greater commitment to prevent bullying and viewed positive teacher and student relationships, there was less bullying, fighting, and peer victimization, and greater willingness to intervene. In a model where all school environment scales were entered together, a school commitment to prevent bullying was associated with less bullying, fighting, and peer victimization. Student-reports of bully perpetration and peer victimization were largely explained by staff and teacher commitment to bully prevention, whereas fighting and willingness to intervene were largely explained by student characteristics (e.g., gender). We conclude that efforts to address bullying and victimization should involve support from the school administration. School psychologists should play an active role in the school climate improvement process, by creating a school climate council consisting of students, parents, and teachers; administering school climate measures; identifying specific school improvement targets from these data, and engaging all stakeholders in the ongoing school improvement plan. PMID:25089334

  5. Relationships between circulating androgens, aggressive behaviour and breeding tubercles in males of the common bream Abramis brama L. in an aquarium environment.

    PubMed

    Poncin, P; Matondo, B Nzau; Termol, C; Kestemont, P; Philippart, J C

    2011-09-01

    In this study, relationships between circulating androgens, aggressive behaviour and breeding tubercles in males of common bream Abramis brama were examined in an aquarium environment. The breeding tubercles of fish were counted, the number of attacks was quantified by male status and circulating rates of testosterone and 11-ketotestosterone from blood plasma were analysed using radioimmunoassay procedures. The results revealed that no significant differences were found between circulating testosterone and 11-ketotestosterone in territorial and nonterritorial males. Furthermore, no significant correlations were found between circulating androgens, androgens and aggression, androgens and tubercles and breeding tubercles and aggression in common bream by male status. However, territorial fish displayed a significantly higher level of aggressive behaviour and breeding tubercles than nonterritorial fish. In natural environments, the occurrence of breeding tubercles during the spawning season could contribute to identifying the behavioural status of common bream males. PMID:21132526

  6. Physical punishment and childhood aggression: the role of gender and gene-environment interplay.

    PubMed

    Boutwell, Brian B; Franklin, Cortney A; Barnes, J C; Beaver, Kevin M

    2011-01-01

    A large body of research has linked spanking with a range of adverse outcomes in children, including aggression, psychopathology, and criminal involvement. Despite evidence concerning the association of spanking with antisocial behavior, not all children who are spanked develop antisocial traits. Given the heterogeneous effects of spanking on behavior, it is possible that a third variable may condition the influence of corporal punishment on child development. We test this possibility using data drawn from a nationally representative dataset of twin siblings. Our findings suggest that genetic risk factors condition the effects of spanking on antisocial behavior. Moreover, our results provide evidence that the interaction between genetic risk factors and corporal punishment may be particularly salient for males. PMID:21898451

  7. Characterizations and hot corrosion resistance of Cr3C2-NiCr coating on Ni-base superalloys in an aggressive environment

    NASA Astrophysics Data System (ADS)

    Sidhu, T. S.; Prakash, S.; Agrawal, R. D.

    2006-12-01

    In the current study, Cr3C2-NiCr coating was deposited on the Ni-base superalloys by using high velocity oxyfuel (HVOF) process for high temperature corrosive environment applications. Optical microscopy (OM), x-ray diffraction (XRD), scanning electron microscopy/energy-dispersive analysis (SEM/EDAX), microhardness tester, and electro probe microanalyzer (EMPA) techniques were used to characterize the coating with regard to coating thickness, porosity, microhardness, and microstructure. The thermogravimetric technique was used to establish kinetics of corrosion. The hot corrosion behaviors of the bare and Cr3C2-NiCr coated superalloys were studied after exposure to aggressive environment of Na2SO4-60% V2O5 salt mixture at 900 °C under cyclic conditions. The structure of the as-sprayed Cr3C2-NiCr coating mainly consisted of γ-nickel solid solution along with minor phases of Cr7C3 and Cr2O3. Coating has porosity less than 1.5% and microhardness in the range of 850-900 Hv (Vickers hardness). Some inclusions, unmelted and semimelted powder particles were observed in the structure of the coatings. The Cr3C2-NiCr coating has imparted necessary resistance to hot corrosion, which has been attributed to the formation of oxides of nickel and chromium, and spinel of nickel-chromium.

  8. The oxidative environment and protein damage.

    PubMed

    Davies, Michael J

    2005-01-17

    Proteins are a major target for oxidants as a result of their abundance in biological systems, and their high rate constants for reaction. Kinetic data for a number of radicals and non-radical oxidants (e.g. singlet oxygen and hypochlorous acid) are consistent with proteins consuming the majority of these species generated within cells. Oxidation can occur at both the protein backbone and on the amino acid side-chains, with the ratio of attack dependent on a number of factors. With some oxidants, damage is limited and specific to certain residues, whereas other species, such as the hydroxyl radical, give rise to widespread, relatively non-specific damage. Some of the major oxidation pathways, and products formed, are reviewed. The latter include reactive species, such as peroxides, which can induce further oxidation and chain reactions (within proteins, and via damage transfer to other molecules) and stable products. Particular emphasis is given to the oxidation of methionine residues, as this species is readily oxidised by a wide range of oxidants. Some side-chain oxidation products, including methionine sulfoxide, can be employed as sensitive, specific, markers of oxidative damage. The product profile can, in some cases, provide valuable information on the species involved; selected examples of this approach are discussed. Most protein damage is non-repairable, and has deleterious consequences on protein structure and function; methionine sulfoxide formation can however be reversed in some circumstances. The major fate of oxidised proteins is catabolism by proteosomal and lysosomal pathways, but some materials appear to be poorly degraded and accumulate within cells. The accumulation of such damaged material may contribute to a range of human pathologies. PMID:15680218

  9. Linkages between Children's and Their Friends' Social and Physical Aggression: Evidence for a Gene-Environment Interaction?

    ERIC Educational Resources Information Center

    Brendgen, Mara; Boivin, Michel; Vitaro, Frank; Bukowski, William M.; Dionne, Ginette; Tremblay, Richard E.; Perusse, Daniel

    2008-01-01

    Based on a sample of 406 seven-year-old twins, this study examined whether exposure to friends' social or physical aggression, respectively, moderates the effect of heritability on children's own social and physical aggression. Univariate analyses showed that children's own social and physical aggression were significantly explained by genetic…

  10. Understanding Driver Anger and Aggression: Attributional Theory in the Driving Environment

    ERIC Educational Resources Information Center

    Wickens, Christine M.; Wiesenthal, David L.; Flora, David B.; Flett, Gordon L.

    2011-01-01

    Two studies tested the applicability of Weiner's (1995, 1996, 2001, 2006) attributional model of social conduct to roadway environments. This model highlights the role of inferences of responsibility after making causal judgments for social transgressions. Study 1 employed written scenarios where participants were asked to imagine themselves…

  11. Oxidation of Haynes 230 alloy in reduced temperature solid oxide fuel cell environments

    NASA Astrophysics Data System (ADS)

    Jian, Li; Jian, Pu; Jianzhong, Xiao; Xiaoliang, Qian

    Haynes 230 alloy was exposed to reducing and oxidizing environments at 750 °C for 1000 h, simulating the conditions in a reduced temperature solid oxide fuel cell (SOFC). The oxidized specimens were characterized in terms of the oxide morphology, composition and crystal structure. The oxide scale in each environment was identified as Cr 2O 3 with the existence of Cr 2MnO 4. Ni remained metallic in the reducing atmosphere, and NiO was detected in the sample exposed to air. The oxide scale is around 1 μm thick after 1000 h of oxidation in both situations. The area specific resistance (ASR) contributed by the oxide scale is expected less than 0.1 Ω cm 2 after 40,000 h of exposure when a parabolic oxide growth rate is assumed, demonstrating the suitability of the interconnect application of this alloy in the reduced temperature SOFCs.

  12. Dual-environment effects on the oxidation of metallic interconnects

    SciTech Connect

    Holcomb, G.R.; Ziomek-Moroz, M.; Covino, B.S., Jr.; Bullard, S.J.

    2006-08-01

    Metallic interconnects in solid oxide fuel cells are exposed to a dual environment: fuel on one side (i.e., H2 gas) and oxidizer on the other side (i.e., air). It has been observed that the oxidation behavior of thin stainless steel sheet in air is changed by the presence of H2 on the other side of the sheet. The resulting dual-environment scales are flaky and more friable than the single-environment scales. The H2 disrupts the scale on the air side. A model to explain some of the effects of a dual environment is presented where hydrogen diffusing through the stainless steel sheet reacts with oxygen diffusing through the scale to form water vapor, which has sufficient vapor pressure to mechanically disrupt the scale. Experiments on preoxidized 316L stainless steel tubing exposed to air-air, H2-air, and H2-Ar environments are reported in support of the model.

  13. Initiating change locally in bullying and aggression through the school environment (INCLUSIVE): a pilot randomised controlled trial.

    PubMed Central

    Bonell, Chris; Fletcher, Adam; Fitzgerald-Yau, Natasha; Hale, Daniel; Allen, Elizabeth; Elbourne, Diana; Jones, Rebecca; Bond, Lyndal; Wiggins, Meg; Miners, Alec; Legood, Rosa; Scott, Stephen; Christie, Deborah; Viner, Russell

    2015-01-01

    BACKGROUND Youth bullying and other aggressive behaviours are a major public health concern owing to their impact on adolescent physical and mental health and well-being. Whole-school restorative approaches have been identified as a promising method of addressing aggressive behaviour but there have been no randomised trials undertaken to examine their effects. AIM To examine the feasibility and acceptability of implementing and trialling the INCLUSIVE (initiating change locally in bullying and aggression through the school environment) intervention in English secondary schools. DESIGN Cluster randomised controlled pilot trial in eight schools (1 : 1 computer-generated random allocation post baseline by a statistician blind to the identity of clusters) and process evaluation. SETTING Secondary schools in England (purposively sampled to ensure diversity). PARTICIPANTS Year 8 students (aged 12-13 years), teachers, other school staff and intervention providers. INTERVENTION Whole-school restorative approach to address bullying and aggression, involving the following standard processes: school action group formation and external facilitation to review needs assessment data, identify priorities, and plan and monitor school-level actions; staff training in restorative practices; and a new social and emotional skills curriculum. COMPARISON GROUP Standard practice. MAIN OUTCOME MEASURES (1) The primary outcome of interest was the feasibility and acceptability of delivering and trialling the intervention according to prespecified criteria; (2) process data were analysed to explore participants' experiences of implementing and trialling the intervention and how these varied according to school context; and (3) indicative primary outcomes (aggressive behaviour measures), secondary outcomes, intermediate outcomes and economic evaluation methods were piloted. DATA SOURCES Students (n = 1144 baseline; n = 1114 follow-up) and teachers (n = 387 baseline; n = 336

  14. ENHANCED COAL REBURNING IN OXIDIZING ENVIRONMENTS

    SciTech Connect

    Eric G. Eddings; Kerry Kelly; Dana W. Overacker; Christopher R. Thurston

    2004-11-01

    Conventional fuel rich coal reburning relies upon two primary mechanisms: (1) the reaction of coal volatiles with NO to form HCN, which can subsequently decay to molecular nitrogen (N{sub 2}) given sufficient residence time at a suitable temperature; and (2), additional NO reduction by reaction of NO with carbon on the coal char surfaces. Recent research has indicated the possibility of HCN release as an additional product during char oxidation, and under appropriate conditions this HCN could provide a third mechanism for reducing NO to N{sub 2}. Lab-scale experiments and kinetic calculations were carried out to identify conditions that might lead to effective coal reburning under oxidizing conditions. The results of the kinetic calculations indicated that, depending on the temperature, oxygen concentrations in the range of 200 ppm to 1000 ppm (0.1%) would provide the greatest levels of gas phase reduction of NO using HCN, and that reductions between 60-80% are possible (in the absence of heterogeneous effects). Experiments using pulverized coal in a laminar flow drop tube furnace demonstrated NO reduction levels as high as 40-50%; however, these experiments were shown to have limited gas/coal contacting. The two different experimental configurations used demonstrated a clear dependence of observed NO reduction efficiency on gas/coal loading. The laboratory results were thus extrapolated to gas/solid loadings more typical of a utility boiler, and this extrapolation indicated that greater levels of NO reductions may well be achievable in a coal-fired boiler application. It was concluded that, given a knowledge of the location of high NO concentrations (obtained for example by CFD modeling), these regions could be targeted with coal injection under slightly oxidizing conditions to obtain NO reductions in excess of the 40-50% levels obtained in the lab-scale experiments. It is recommended that further testing under conventional pulverized coal combustion conditions be

  15. MULTI-PHASE Cr-BASED ALLOYS FOR AGGRESSIVE HIGH TEMPERATURE ENVIRONMENTS

    SciTech Connect

    Brady, MP

    2001-08-24

    Attractive high-temperature mechanical properties and oxidation/hot corrosion resistance have been achieved in a new family of Cr{sub 2}Ta-reinforced Cr alloys. However, inadequate room-temperature toughness remains a key challenge, with the best Cr-Cr{sub 2}Ta alloys exhibiting only modest toughness in the range of 12-14 MPa m{sup 1/2}. The addition of MgO has been shown to significantly improve the room-temperature mechanical properties of unalloyed Cr and was investigated as a means for improving the room-temperature mechanical properties of the Cr-Cr{sub 2}Ta alloys. Microstructural analysis of a series of Cr and Cr-6MgO base alloys was used to investigate the proposed ductilization mechanism of nitrogen gettering by a MgCr{sub 2}O{sub 4} spinel phase, which forms during consolidation of Cr and MgO powders. Nitride and related impurity precipitates have been linked to reduced ductility in Cr at room-temperature. Surprisingly, nitride (and carbide) impurity precipitates were found i n hot-pressed Cr-6 MgO base alloys despite room-temperature tensile ductility of 5%. These precipitates were found adjacent to MgO/MgCr{sub 2}O{sub 4} particles and were somewhat more blunt than those observed in unalloyed Cr. The addition of TiO{sub 2} to unalloyed Cr resulted in similar morphological changes to the nitride and carbide impurity precipitates; however, the TiO{sub 2} dispersed alloy was brittle at room-temperature. Why MgO dispersions are effective in ductilizing Cr, but others such as TiO{sub 2} are not, is not clear and is the subject of ongoing study. Efforts to introduce the effect in Cr-Cr{sub 2}Ta-MgO alloys were not successful, and it was concluded that significant modification of the Cr matrix phase in the Cr-Cr{sub 2}Ta alloys by macroalloying is necessary to improve room-temperature mechanical properties. Preliminary attempts at macroalloying with Fe were quite successful and resulted in an increase in room-temperature toughness to 18-20 MPa m{sup 1/2} in Cr

  16. Angry and Aggressive Students

    ERIC Educational Resources Information Center

    Larson, Jim

    2008-01-01

    Students who engage in physical aggression in school present a serious challenge to maintaining a safe and supportive learning environment. Unlike other forms of student aggression, fighting is explicit, is violent, and demands attention. A fight between students in a classroom, hallway, or the lunchroom brings every other activity to a halt and…

  17. Testosterone and Aggression.

    ERIC Educational Resources Information Center

    Archer, John

    1994-01-01

    Studies comparing aggressive and nonaggressive prisoners show higher testosterone levels among the former. While there is limited evidence for a strong association between aggressiveness and testosterone during adolescence, other studies indicate that testosterone levels are responsive to influences from the social environment, particularly those…

  18. Oxidation of Carbon Nanotubes in an Ionizing Environment.

    PubMed

    Koh, Ai Leen; Gidcumb, Emily; Zhou, Otto; Sinclair, Robert

    2016-02-10

    In this work, we present systematic studies on how an illuminating electron beam which ionizes molecular gas species can influence the mechanism of carbon nanotube oxidation in an environmental transmission electron microscope (ETEM). We found that preferential attack of the nanotube tips is much more prevalent than for oxidation in a molecular gas environment. We establish the cumulative electron doses required to damage carbon nanotubes from 80 keV electron beam irradiation in gas versus in high vacuum. Our results provide guidelines for the electron doses required to study carbon nanotubes within or without a gas environment, to determine or ameliorate the influence of the imaging electron beam. This work has important implications for in situ studies as well as for the oxidation of carbon nanotubes in an ionizing environment such as that occurring during field emission. PMID:26726919

  19. Simple self-gettering differential-pump for minimizing source oxidation in oxide-MBE environment

    SciTech Connect

    Kim, Yong-Seung; Bansal, Namrata; Oh, Seongshik

    2011-07-15

    Source oxidation of easily oxidizing elements such as Ca, Sr, Ba, and Ti in an oxidizing ambient leads to their flux instability and is one of the biggest problems in the multielemental oxide molecular beam epitaxy technique. Here, the authors report a new scheme that can completely eliminate the source oxidation problem: a self-gettering differential pump using the source itself as the pumping medium. The pump simply comprises a long collimator mounted in front of the source in extended port geometry. With this arrangement, the oxygen partial pressure near the source was easily maintained well below the source oxidation regime, resulting in a stabilized flux, comparable to that of an ultrahigh-vacuum environment. Moreover, this pump has a self-feedback mechanism that allows a stronger pumping effectiveness for more easily oxidizing elements, which is a desired property for eliminating the source oxidation problem.

  20. Aspects of Juvenile and Adolescent Environment Predict Aggression and Fear in 12-Month-Old Guide Dogs.

    PubMed

    Serpell, James A; Duffy, Deborah L

    2016-01-01

    Maturational changes in behavior, and the possible influence of the puppy-raising environment on behavioral development, were investigated in a total sample of 978 prospective guide dogs belonging to four different breeds/crosses. All dogs belonged to the same guide dog organization, and had been exposed to similar early environmental influences prior to being assigned to puppy-raising households at 7-8 weeks of age. Behavioral data were collected from puppy raisers when the dogs were 6 and 12 months old using the C-BARQ(©), a standardized, validated, and widely used survey instrument that measures the frequency and/or severity of most common behavior problems in dogs. Information about the puppy-raising environment was obtained from puppy raisers using a standardized questionnaire shortly before the dogs were returned to the guide dog organization for training. Data were analyzed using both univariate and multivariate statistics (binary logistic generalized estimating equations modeling and generalized linear modeling). The findings demonstrated specific maturational changes in behavior between 6 and 12 months of age. In particular, German Shepherd dogs displayed an increase in stranger-directed aggression compared with the other breeds/crosses between 6 and 12 months of age. Several aspects of the puppy-raising environment were associated with puppies' C-BARQ scores at 12 months of age. In particular, growing up in households with more experienced puppy raisers, and in the company of at least one other dog, were both associated with positive effects on a number of puppy behaviors. By contrast, puppies that had been frightened by a person or threatened by another unfamiliar dog showed significantly worse scores for fear of strangers and dogs, respectively. Being frightened by a person, being reared by less experienced puppy raisers, and/or in households without other pets were associated with less successful training outcomes. The relevance of these

  1. Aspects of Juvenile and Adolescent Environment Predict Aggression and Fear in 12-Month-Old Guide Dogs

    PubMed Central

    Serpell, James A.; Duffy, Deborah L.

    2016-01-01

    Maturational changes in behavior, and the possible influence of the puppy-raising environment on behavioral development, were investigated in a total sample of 978 prospective guide dogs belonging to four different breeds/crosses. All dogs belonged to the same guide dog organization, and had been exposed to similar early environmental influences prior to being assigned to puppy-raising households at 7–8 weeks of age. Behavioral data were collected from puppy raisers when the dogs were 6 and 12 months old using the C-BARQ©, a standardized, validated, and widely used survey instrument that measures the frequency and/or severity of most common behavior problems in dogs. Information about the puppy-raising environment was obtained from puppy raisers using a standardized questionnaire shortly before the dogs were returned to the guide dog organization for training. Data were analyzed using both univariate and multivariate statistics (binary logistic generalized estimating equations modeling and generalized linear modeling). The findings demonstrated specific maturational changes in behavior between 6 and 12 months of age. In particular, German Shepherd dogs displayed an increase in stranger-directed aggression compared with the other breeds/crosses between 6 and 12 months of age. Several aspects of the puppy-raising environment were associated with puppies’ C-BARQ scores at 12 months of age. In particular, growing up in households with more experienced puppy raisers, and in the company of at least one other dog, were both associated with positive effects on a number of puppy behaviors. By contrast, puppies that had been frightened by a person or threatened by another unfamiliar dog showed significantly worse scores for fear of strangers and dogs, respectively. Being frightened by a person, being reared by less experienced puppy raisers, and/or in households without other pets were associated with less successful training outcomes. The relevance of these

  2. Effects of environment on microhardness of magnesium oxide

    NASA Technical Reports Server (NTRS)

    Ishigaki, H.; Buckley, D. H.

    1982-01-01

    Micro-Vickers hardness measurements of magnesium oxide single crystals were conducted in various environments. These environments included air, nitrogen gas, water, mineral oil with or without various additives, and aqueous solutions with various pH values. Indentations were made on the (100) plane with the diagonals of the indentation in the (100) direction. The results indicate that a sulfur containing additve in mineral oil increased hardness, a chlorine containing additive in mineral oil decreased hardness, and aqueous solutions of hydrogen chloride decreased hardness. Other environments were found to have little effect on hardness. Mechanically polished surfaces showed larger indentation creep than did as-cleaved surfaces.

  3. Dual Environment Effects on the Oxidation of Metallic Interconnects

    SciTech Connect

    Holcomb, Gordon R.; Ziomek-Moroz, Malgorzata; Cramer, Stephen D.; Covino, Jr., Bernard S.; and Bullard, Sophie J.

    2004-10-20

    Metallic interconnects in solid oxide fuel cells are exposed to a dual environment: fuel on one side (i.e. H2 gas) and oxidizer on the other side (i.e. air). It has been observed that the oxidation behavior of thin stainless steel sheet in air is changed by the presence of H2 on the other side of the sheet. The resulting dual environment scales are flaky and more friable than the single environment scales. The H2 disrupts the scale on the air-side. A model to explain some of the effects of a dual environment is presented where hydrogen diffusing through the stainless steel sheet reacts with oxygen diffusing through the scale to form water vapor, which has sufficient vapor pressure to mechanically disrupt the scale. Experiments on preoxidized 316L stainless steel tubing exposed to air/air, H2/air, and H2/Ar environments are reported in support of the model.

  4. Influence of hydrogen oxidation kinetics on hydrogen environment embrittlement

    NASA Technical Reports Server (NTRS)

    Walter, R. J.; Kendig, M. W.; Meisels, A. P.

    1992-01-01

    Results are presented from experiments performed to determine the roles of hydrogen absorption and hydrogen electron transfer on the susceptibility of Fe- and Ni-base alloys to ambient-temperature hydroen embrittlement. An apparent independence is noted between hydrogen environment embrittlement and internal hydrogen embrittlement. The experiments were performed on Inconel 718, Incoloy 903, and A286. The electrochemical results obtained indicate that Inconel 718 either adsorbs hydrogen more rapidly and/or the electrochemical oxidation of the adsorbed hydrogen occurred more rapidly than in the other two materials.

  5. Spaceflight environment induces mitochondrial oxidative damage in ocular tissue.

    PubMed

    Mao, Xiao W; Pecaut, Michael J; Stodieck, Louis S; Ferguson, Virginia L; Bateman, Ted A; Bouxsein, Mary; Jones, Tamako A; Moldovan, Maria; Cunningham, Christopher E; Chieu, Jenny; Gridley, Daila S

    2013-10-01

    A recent report shows that more than 30% of the astronauts returning from Space Shuttle missions or the International Space Station (ISS) were diagnosed with eye problems that can cause reduced visual acuity. We investigate here whether spaceflight environment-associated retinal damage might be related to oxidative stress-induced mitochondrial apoptosis. Female C57BL/6 mice were flown in the space shuttle Atlantis (STS-135), and within 3-5 h of landing, the spaceflight and ground-control mice, similarly housed in animal enclosure modules (AEMs) were euthanized and their eyes were removed for analysis. Changes in expression of genes involved in oxidative stress, mitochondrial and endothelial cell biology were examined. Apoptosis in the retina was analyzed by caspase-3 immunocytochemical analysis and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay. Levels of 4-hydroxynonenal (4-HNE) protein, an oxidative specific marker for lipid peroxidation were also measured. Evaluation of spaceflight mice and AEM ground-control mice showed that expression of several genes playing central roles in regulating the mitochondria-associated apoptotic pathway were significantly altered in mouse ocular tissue after spaceflight compared to AEM ground-control mice. In addition, the mRNA levels of several genes, which are responsible for regulating the production of reactive oxygen species were also significantly up-regulated in spaceflight samples compared to AEM ground-control mice. Further more, the level of HNE protein was significantly elevated in the retina after spaceflight compared to controls. Our results also revealed that spaceflight conditions induced significant apoptosis in the retina especially inner nuclear layer (INL) and ganglion cell layer (GCL) compared to AEM ground controls. The data provided the first evidence that spaceflight conditions induce oxidative damage that results in mitochondrial apoptosis in the retina. This data suggest

  6. Psychological Research on Human Aggressiveness

    ERIC Educational Resources Information Center

    Hamburg, D. A.; Brodie, H. K. H.

    1973-01-01

    Discusses research relating to the effects of hormones, neurophysiology, and the environment on animal and human aggression. Indicates that the interactions of biological, psychological and social processes in the development of human aggressiveness should constitute one of the principal frontiers for science in the next two decades. (JR)

  7. Diffusion Limited Supercritical Water Oxidation (SCWO) in Microgravity Environments

    NASA Technical Reports Server (NTRS)

    Hicks, M. C.; Lauver, R. W.; Hegde, U. G.; Sikora, T. J.

    2006-01-01

    Tests designed to quantify the gravitational effects on thermal mixing and reactant injection in a Supercritical Water Oxidation (SCWO) reactor have recently been performed in the Zero Gravity Facility (ZGF) at NASA s Glenn Research Center. An artificial waste stream, comprising aqueous mixtures of methanol, was pressurized to approximately 250 atm and then heated to 450 C. After uniform temperatures in the reactor were verified, a controlled injection of air was initiated through a specially designed injector to simulate diffusion limited reactions typical in most continuous flow reactors. Results from a thermal mapping of the reaction zone in both 1-g and 0-g environments are compared. Additionally, results of a numerical model of the test configuration are presented to illustrate first order effects on reactant mixing and thermal transport in the absence of gravity.

  8. High temperature oxidation of molybdenum in water vapor environments

    NASA Astrophysics Data System (ADS)

    Nelson, A. T.; Sooby, E. S.; Kim, Y.-J.; Cheng, B.; Maloy, S. A.

    2014-05-01

    Molybdenum has recently gained attention as a candidate cladding material for use in light water reactors. Its excellent high temperature mechanical properties and stability under irradiation suggest that it could offer benefits to performance under a wide range of reactor conditions, but little is known about its oxidation behavior in water vapor containing atmospheres. The current study was undertaken to elucidate the oxidation behavior of molybdenum in water vapor environments to 1200 °C in order to provide an initial assessment of its feasibility as a light water reactor cladding. Initial observations indicate that at temperatures below 1000 °C, the kinetics of mass loss in water vapor would not be detrimental to cladding integrity during an off-normal event. Above 1000 °C, degradation is more rapid but remains slower than observed for optimized zirconium cladding alloys. The effect of hydrogen-water vapor and oxygen-water vapor mixtures on material loss was also explored at elevated temperatures. Parts-per-million levels of either hydrogen or oxygen will minimally impact performance, but hydrogen contents in excess of 1000 ppm were observed to limit volatilization at 1000 °C.

  9. Colloidal properties and stability of graphene oxide nanomaterials in the aquatic environment.

    PubMed

    Chowdhury, Indranil; Duch, Matthew C; Mansukhani, Nikhita D; Hersam, Mark C; Bouchard, Dermont

    2013-06-18

    While graphene oxide (GO) has been found to be the most toxic graphene-based nanomaterial, its environmental fate is still unexplored. In this study, the aggregation kinetics and stability of GO were investigated using time-resolved dynamic light scattering over a wide range of aquatic chemistries (pH, salt types (NaCl, MgCl2, CaCl2), ionic strength) relevant to natural and engineered systems. Although pH did not have a notable influence on GO stability from pH 4 to 10, salt type and ionic strength had significant effects on GO stability due to electrical double layer compression, similar to other colloidal particles. The critical coagulation concentration (CCC) values of GO were determined to be 44 mM NaCl, 0.9 mM CaCl2, and 1.3 mM MgCl2. Aggregation and stability of GO in the aquatic environment followed colloidal theory (DLVO and Schulze-Hardy rule), even though GO's shape is not spherical. CCC values of GO were lower than reported fullerene CCC values and higher than reported carbon nanotube CCC values. CaCl2 destabilized GO more aggressively than MgCl2 and NaCl due to the binding capacity of Ca(2+) ions with hydroxyl and carbonyl functional groups of GO. Natural organic matter significantly improved the stability of GO in water primarily due to steric repulsion. Long-term stability studies demonstrated that GO was highly stable in both natural and synthetic surface waters, although it settled quickly in synthetic groundwater. While GO remained stable in synthetic influent wastewater, effluent wastewater collected from a treatment plant rapidly destabilized GO, indicating GO will settle out during the wastewater treatment process and likely accumulate in biosolids and sludge. Overall, our findings indicate that GO nanomaterials will be stable in the natural aquatic environment and that significant aqueous transport of GO is possible. PMID:23668881

  10. Nickel aluminides and nickel-iron aluminides for use in oxidizing environments

    DOEpatents

    Liu, Chain T.

    1988-03-15

    Nickel aluminides and nickel-iron aluminides treated with hafnium or zirconium, boron and cerium to which have been added chromium to significantly improve high temperature ductility, creep resistance and oxidation properties in oxidizing environments.

  11. Gene by Social-Environment Interaction for Youth Delinquency and Violence: Thirty-Nine Aggression-related Genes

    PubMed Central

    Liu, Hexuan; Li, Yi; Guo, Guang

    2014-01-01

    Complex human traits are likely to be affected by many environmental and genetic factors, and the interactions among them. However, previous gene-environment interaction (G×E) studies have typically focused on one or only a few genetic variants at a time. To provide a broader view of G×E, this study examines the relationship between 403 genetic variants from 39 genes and youth delinquency and violence. We find evidence that low social control is associated with greater genetic risk for delinquency and violence and high/moderate social control with smaller genetic risk for delinquency and violence. Our findings are consistent with prior G×E studies based on a small number of genetic variants, and, more importantly, we show that these findings still hold when a large number of genetic variants are considered simultaneously. A key implication of these findings is that the expression of multiple genes related to delinquency depends on the social environment: gene expression is likely to be amplified in low-social-control environments but, tends to be suppressed in high/moderate-social-control environments. This study not only deepens our understanding of how the social environment shapes individual behavior, but also provides important conceptual and methodological insights for future G×E research on complex human traits. PMID:25755300

  12. Cyclic oxidation behavior of some plasma-sprayed coatings in Na2SO4-60%V2O5 environment

    NASA Astrophysics Data System (ADS)

    Singh, Harpreet; Prakash, Satya; Puri, Devendra; Phase, D. M.

    2006-12-01

    Cyclic oxidation behavior of plasma-sprayed NiCrAlY, Ni-20Cr, Ni3Al, and Stellite-6 coatings was investigated in an aggressive environment of Na2SO4-60%V2O5 by thermogravimetric techniques for 50 cycles. These coatings were deposited on a Ni-base superalloy, namely Superni 600; 10Fe-15.5Cr-0.5Mn-0.2C-Bal Ni (wt.%). X-ray diffraction, scanning electron microscopy/energy dispersive x-ray (SEM/EDX), and electron probe microanalyzer (EPMA) techniques were used to analyze the oxidation products. The uncoated superalloy suffered accelerated oxidation in the form of intense spallation of its oxide scale. After deposition of the NiCrAlY coating, the superalloy showed a minimum mass gain, whereas after application of the Stellite-6 coating, a maximum mass gain was observed among the coatings studied. All of the coatings were found to be useful in reducing the spallation of the substrate superalloy. Moreover, the coatings were successful in maintaining continuous surface contact with the base superalloy during the cyclic oxidation. The phases revealed for the oxidized coatings were mainly the oxides of chromium and/or aluminum and the spinels containing nickel-chromium/cobalt-chromium/nickel-aluminum mixed oxides, which are reported to be protective against high-temperature oxidation/hot corrosion.

  13. Evaluation of the Fracture Toughness of a SMSS Subjected to Common Heat Treatment Cycles in an Aggressive Environment

    NASA Astrophysics Data System (ADS)

    Pieta, G.; Leite, R.; Kwietniewski, C.; Clarke, T.; Strohaecker, T.

    2010-12-01

    Supermartensitic stainless steels (SMSS) are an alternative to corrosion-prone carbon steels and expensive duplex stainless steels in offshore tubing applications for the oil and gas industry. Due to their differentiated alloying, SMSS exhibit superior toughness, corrosion resistance, and weldability properties when compared with another viable option, conventional martensitic stainless steels. However, when cathodically protected in a seawater environment they can be susceptible to embrittlement due to hydrogen charging. In the present study, SMSS samples were removed from deep water pipelines and their fracture toughness in the as-received condition and with different heat treatments was evaluated. Tests were carried out in air and in harsh environmental and loading conditions, which were ensured by subjecting specimens to cathodic overprotection, simulating effects seen in structures with complex geometries, and to incremental step loads in a synthetic seawater environment, thus favoring hydrogen diffusion to the precrack tip. The fracture surfaces of the specimens were analyzed in order to identify hydrogen-induced embrittlement and fracture toughness values of specimens tested in air were compared to values obtained in environment-assisted experiments. The influence of microstructure was evaluated by control of the retained austenite and δ-ferrite contents of the specimens. The results show a significant drop in the fracture toughness of steel in the studied environment, with a fracture mode which is clearly more brittle and dependent on microstructural characteristics of the samples.

  14. ROS Initiated Oxidation of Dopamine under Oxidative Stress Conditions in Aqueous and Lipidic Environments

    PubMed Central

    2011-01-01

    Dopamine is known to be an efficient antioxidant and to protect neurocytes from oxidative stress by scavenging free radicals. In this work, we have carried out a systematic quantum chemistry and computational kinetics study on the reactivity of dopamine toward hydroxyl (•OH) and hydroperoxyl (•OOH) free radicals in aqueous and lipidic simulated biological environments, within the density functional theory framework. Rate constants and branching ratios for the different paths contributing to the overall reaction, at 298 K, are reported. For the reactivity of dopamine toward hydroxyl radicals, in water at physiological pH, the main mechanism of the reaction is proposed to be the sequential electron proton transfer (SEPT), whereas in the lipidic environment, hydrogen atom transfer (HAT) and radical adduct formation (RAF) pathways contribute almost equally to the total reaction rate. In both environments, dopamine reacts with hydroxyl radicals at a rate that is diffusion-controlled. Reaction with the hydroperoxyl radical is much slower and occurs only by abstraction of any of the phenolic hydrogens. The overall rate coefficients are predicted to be 2.23 × 105 and 8.16 × 105 M–1 s–1, in aqueous and lipidic environment, respectively, which makes dopamine a very good •OOH, and presumably •OOR, radical scavenger. PMID:21919526

  15. Autotrophic, sulfur-oxidizing actinobacteria in acidic environments.

    PubMed

    Norris, Paul R; Davis-Belmar, Carol S; Brown, Carly F; Calvo-Bado, Leonides A

    2011-03-01

    Some novel actinobacteria from geothermal environments were shown to grow autotrophically with sulfur as an energy source. These bacteria have not been formally named and are referred to here as "Acidithiomicrobium" species, as the first of the acidophilic actinobacteria observed to grow on sulfur. They are related to Acidimicrobium ferrooxidans with which they share a capacity for ferrous iron oxidation. Ribulose bisphosphate carboxylase/oxygenase (RuBisCO) is active in CO(2) fixation by Acidimicrobium ferrooxidans, which appears to have acquired its RuBisCO-encoding genes from the proteobacterium Acidithiobacillus ferrooxidans or its ancestor. This lateral transfer of RuBisCO genes between a proteobacterium and an actinobacterium would add to those noted previously among proteobacteria, between proteobacteria and cyanobacteria and between proteobacteria and plastids. "Acidithiomicrobium" has RuBisCO-encoding genes which are most closely related to those of Acidimicrobium ferrooxidans and Acidithiobacillus ferrooxidans, and has additional RuBisCO genes of a different lineage. 16S rRNA gene sequences from "Acidithiomicrobium" species dominated clone banks of the genes extracted from mixed cultures of moderate thermophiles growing on copper sulfide and polymetallic sulfide ores in ore leaching columns. PMID:21308384

  16. Transport of Zinc Oxide Nanoparticles in a Simulated Gastric Environment

    NASA Astrophysics Data System (ADS)

    Mayfield, Ryan T.

    Recent years have seen a growing interest in the use of many types of nano sized materials in the consumer sector. Potential uses include encapsulation of nutrients, providing antimicrobial activity, altering texture, or changing bioavailability of nutrients. Engineered nanoparticles (ENP) possess properties that are different than larger particles made of the same constituents. Properties such as solubility, aggregation state, and toxicity can all be changed as a function of size. The gastric environment is an important area for study of engineered nanoparticles because of the varied physical, chemical, and enzymatic processes that are prevalent there. These all have the potential to alter those properties of ENP that make them different from their bulk counterparts. The Human Gastric Simulator (HGS) is an advanced in vitro model that can be used to study many facets of digestion. The HGS consists of a plastic lining that acts as the stomach cavity with two sets of U-shaped arms on belts that provide the physical forces needed to replicate peristalsis. Altering the position of the arms or changing the speed of the motor which powers them allows one to tightly hone and replicate varied digestive conditions. Gastric juice, consisting of salts, enzymes, and acid levels which replicate physiological conditions, is introduced to the cavity at a controllable rate. The release of digested food from the lumen of simulated stomach is controlled by a peristaltic pump. The goal of the HGS is to accurately and repeatedly simulate human digestion. This study focused on introducing foods spiked with zinc oxide ENP and bulk zinc oxide into the HGS and then monitoring how the concentration of each changed at two locations in the HGS over a two hour period. The two locations chosen were the highest point in the lumen of the stomach, which represented the fundus, and a point just beyond the equivalent of the pylorus, which represented the antrum of the stomach. These points were

  17. How aggressive are coastal cliff environments? Monitoring micro-environmental conditions on an actively eroding rock cliff.

    NASA Astrophysics Data System (ADS)

    Lim, Michael; Rosser, Nicholas; Petley, David; Norman, Emma; Brain, Matthew; Barlow, John

    2010-05-01

    Despite their widespread occurrence, the behaviour of coastal rock cliffs, and in particular the balance between the marine and subaerial conditions that promote erosion, is poorly understood. This is mainly due to a lack of direct, quantitative data on process and response in this type of environment. This paper investigates how near-cliff environmental processes can be associated with the occurrence of rockfalls, which we argue contribute the majority of material lost from coastal cliffs. A detailed recent history of rockfall volumes, dating back to 2003, has been collected using repeat terrestrial laser scans of a 70 m high cliff section on the North Yorkshire coast, UK. This dataset is complimented with a bespoke environmental monitoring system installed upon the cliff face, which allows the influence of weathering and erosion processes on the magnitude and frequency of rockfalls to be analysed. This system is comprised of three instrument clusters at nodes that correspond to three main lithological units of the cliff, hard wired to a communications unit at the top of the cliff face. Data is collected on air temperature, humidity, irradiance, wind and precipitation. Within the near surface of the rock mass we also measure temperature, rock moisture, surface wetness and strain, to allow the direct physical response of the rock to be quantified. The cliff (local) environment monitoring system demonstrates that the rock undergoes significantly greater variability than can be identified from more generic regional weather and tide datasets, predominantly as a function of the angular geometry of the cliff face, resulting in rapid gradients of change. For example, daily variations in temperature and moisture can be seen to have a significant and direct effect on the strain responses of the rock. We seek to establish this as a long-term dataset, to provide a new quantitative assessment of the links between regional and hinterland weather conditions and those found on

  18. Engineering functionalized multi-phased silicon/silicon oxide nano-biomaterials to passivate the aggressive proliferation of cancer

    PubMed Central

    Premnath, P.; Tan, B.; Venkatakrishnan, K.

    2015-01-01

    Currently, the use of nano silicon in cancer therapy is limited as drug delivery vehicles and markers in imaging, not as manipulative/controlling agents. This is due to limited properties that native states of nano silicon and silicon oxides offers. We introduce nano-functionalized multi-phased silicon/silicon oxide biomaterials synthesized via ultrashort pulsed laser synthesis, with tunable properties that possess inherent cancer controlling properties that can passivate the progression of cancer. This nanostructured biomaterial is composed of individual functionalized nanoparticles made of a homogenous hybrid of multiple phases of silicon and silicon oxide in increasing concentration outwards from the core. The chemical properties of the proposed nanostructure such as number of phases, composition of phases and crystal orientation of each functionalized nanoparticle in the three dimensional nanostructure is defined based on precisely tuned ultrashort pulsed laser-material interaction mechanisms. The amorphous rich phased biomaterial shows a 30 fold (95%) reduction in number of cancer cells compared to bulk silicon in 48 hours. Further, the size of the cancer cells reduces by 76% from 24 to 48 hours. This method exposes untapped properties of combination of multiple phases of silicon oxides and its applications in cancer therapy. PMID:26190009

  19. Longitudinal heritability of childhood aggression.

    PubMed

    Porsch, Robert M; Middeldorp, Christel M; Cherny, Stacey S; Krapohl, Eva; van Beijsterveldt, Catharina E M; Loukola, Anu; Korhonen, Tellervo; Pulkkinen, Lea; Corley, Robin; Rhee, Soo; Kaprio, Jaakko; Rose, Richard R; Hewitt, John K; Sham, Pak; Plomin, Robert; Boomsma, Dorret I; Bartels, Meike

    2016-07-01

    The genetic and environmental contributions to the variation and longitudinal stability in childhood aggressive behavior were assessed in two large twin cohorts, the Netherlands Twin Register (NTR), and the Twins Early Development Study (TEDS; United Kingdom). In NTR, maternal ratings on aggression from the Child Behavior Checklist (CBCL) were available for 10,765 twin pairs at age 7, for 8,557 twin pairs at age 9/10, and for 7,176 twin pairs at age 12. In TEDS, parental ratings of conduct disorder from the Strength and Difficulty Questionnaire (SDQ) were available for 6,897 twin pairs at age 7, for 3,028 twin pairs at age 9 and for 5,716 twin pairs at age 12. In both studies, stability and heritability of aggressive behavioral problems was high. Heritability was on average somewhat, but significantly, lower in TEDS (around 60%) than in NTR (between 50% and 80%) and sex differences were slightly larger in the NTR sample. In both studies, the influence of shared environment was similar: in boys shared environment explained around 20% of the variation in aggression across all ages while in girls its influence was absent around age 7 and only came into play at later ages. Longitudinal genetic correlations were the main reason for stability of aggressive behavior. Individual differences in CBCL-Aggressive Behavior and SDQ-Conduct disorder throughout childhood are driven by a comparable but significantly different genetic architecture. © 2016 Wiley Periodicals, Inc. PMID:26786601

  20. Sunlight affects aggregation and deposition of graphene oxide in the aquatic environment.

    EPA Science Inventory

    In this study, we investigate the role of simulated sunlight on the physicochemical properties, aggregation, and deposition of graphene oxide (GO) in aquatic environments. Results show that light exposure under varied environmental conditions significantly impacts the physicochem...

  1. Oxidation in Environments with Elevated CO2 Levels

    SciTech Connect

    Gordon H. Holcomb

    2009-05-01

    Efforts to reduce greenhouse gas emissions from fossil energy power productions focus primarily on either pre- or post-combustion removal of CO2. The research presented here examines corrosion and oxidation issues associated with two types of post-combustion CO2 removal processes—oxyfuel combustion in refit boilers and oxyfuel turbines.

  2. Electronically conductive ceramics for high temperature oxidizing environments

    DOEpatents

    Kucera, Gene H.; Smith, James L.; Sim, James W.

    1986-01-01

    A high temperature, ceramic composition having electronic conductivity as measured by resistivity below about 500 ohm-cm, chemical stability particularly with respect to cathode conditions in a molten carbonate fuel cell, and composed of an alkali metal, transition metal oxide containing a dopant metal in the crystalline structure to replace a portion of the alkali metal or transition metal.

  3. Electronically conductive ceramics for high temperature oxidizing environments

    DOEpatents

    Kucera, G.H.; Smith, J.L.; Sim, J.W.

    1983-11-10

    This invention pertains to a high temperature, ceramic composition having electronic conductivity as measured by resistivity below about 500 ohm-cm, chemical stability particularly with respect to cathode conditions in a molten carbonate fuel cell, and composed of an alkali metal, transition metal oxide containing a dopant metal in the crystalline structure to replace a portion of the alkali metal or transition metal.

  4. CONCEPT ANALYSIS: AGGRESSION

    PubMed Central

    Liu, Jianghong

    2006-01-01

    The concept of aggression is important to nursing because further knowledge of aggression can help generate a better theoretical model to drive more effective intervention and prevention approaches. This paper outlines a conceptual analysis of aggression. First, the different forms of aggression are reviewed, including the clinical classification and the stimulus-based classification. Then the manifestations and measurement of aggression are described. Finally, the causes and consequences of aggression are outlined. It is argued that a better understanding of aggression and the causal factors underlying it are essential for learning how to prevent negative aggression in the future. PMID:15371137

  5. Concept analysis: aggression.

    PubMed

    Liu, Jianghong

    2004-01-01

    The concept of aggression is important to nursing because further knowledge of aggression can help generate a better theoretical model to drive more effective intervention and prevention approaches. This paper outlines a conceptual analysis of aggression. First, the different forms of aggression are reviewed, including the clinical classification and the stimulus-based classification. Then the manifestations and measurement of aggression are described. Finally, the causes and consequences of aggression are outlined. It is argued that a better understanding of aggression and the causal factors underlying it are essential for learning how to prevent negative aggression in the future. PMID:15371137

  6. Oxidation of 316 stainless steel and other alloys in prototypic GCFR environments

    SciTech Connect

    Acharya, R.T.

    1980-05-01

    The oxidation behavior of type 316 stainless steel and candidate advanced alloys for the gas-cooled fast reactor (GCFR) is being investigated at General Atomic Company. The test program consists of oxidation tests in prototypic GCFR environments. Two tests have been completed to date and a third test is under way. The first test was performed in an environment containing a hydrogen/water ratio of 10. The oxidation behavior of all the alloys was good to excellent in this environment. Preferential oxidation of chromium was responsible for this behavior. The second test was performed in an environment containing a hydrogen/water ratio of 0.25, where both chromium and iron oxides are thermodynamically stable. Some of the alloys and some of the ribbed type 316 stainless steel test specimens showed unacceptable oxidation resistance in this environment. In the third test, presently under way, two different pretreatment procedures are being used to control the poor oxidation behavior observed in the second test. Early results show some degree of success.

  7. Decomposition of ethylene oxide in the RF plasma environment.

    PubMed

    Liao, W T; Lee, W J; Chen, C Y; Shih, M

    2001-02-01

    A radio frequency (RF) plasma system was used to decompose the ethylene oxide (EO) contained gas in the EO/Ar, and EO/O2/Ar system, respectively. The reactants and final products were analyzed by using FTIR (Fourier transform infrared spectroscopy). The effects of plasma operational parameters, including input power wattage (W), total gas flow rate (Q), feeding concentration (C) of EO and operational pressure for EO decomposition were evaluated. Due to the importance of the high-energy electrons in the RF plasma system, the EO decomposition fraction in plasma reaction increased with decreasing operational pressure, while that of thermal reaction, reported by previous investigations, increased with increasing operational pressure. However, owing to the electrophilic characteristic of oxygen atoms in the EO molecule causing the effect of electron attachment, in conditions of higher EO feeding concentration, the pressure dependence became the same for both plasma- and thermal-reaction. The EO oxidation reaction has also been investigated, the result shows that EO almost completely oxidized at 600-692 K gas temperature. The main products for the EO/Ar system are CO, CH4, C2H6, C2H4, and C2H2, and those for the EO/O2/Ar system are CO2 and H2O. PMID:11349375

  8. Oxidation behavior of TD-NiCr in a dynamic high temperature environment

    NASA Technical Reports Server (NTRS)

    Tenney, D. R.; Young, C. T.; Herring, H. W.

    1974-01-01

    The oxidation behavior of TD-NiCr has been studied in static and high-speed flowing air environments at 1100 and 1200 C. It has been found that the stable oxide morphologies formed on the specimens exposed to the static and dynamic environments were markedly different. The faceted crystal morphology characteristic of static oxidation was found to be unstable under high-temperature, high-speed flow conditions and was quickly replaced by a porous NiO 'mushroom' type structure. Also, it was found that the rate of formation of CrO3 from Cr2O3 was greatly enhanced by high gas velocity conditions. The stability of Cr2-O3 was found to be greatly improved by the presence of an outer NiO layer, even though the NiO layer was very porous. An oxidation model is proposed to explain the observed microstructures and overall oxidation behavior of TD-NiCr alloys.

  9. Niobium alloy heat pipes for use in oxidizing environments

    NASA Astrophysics Data System (ADS)

    Craig Wojcik, C.

    1991-01-01

    Niobium alloys have been used for many years in rocket propulsion systems and afterburner sections of gas turbine engines. In these applications, adequate oxidation resistance is provided by protective silicide coatings. By utilizing these coatings and niobium powder metallurgy to produce porous wicks, it has been demonstrated that niobium alloy heat pipes can comfortably operate in flame temperatures exceeding 3000 K. Results of lithium corrosion tests on C-103 (Nb-10%Hf-1%Ti) up to 1477 K will be presented along with thermal performance data for specific heat pipe designs.

  10. Niobium alloy heat pipes for use in oxidizing environments

    NASA Astrophysics Data System (ADS)

    Wojcik, C. C.

    Nb-alloy heat pipes employing oxidation-protection silicide coatings in conjunction with P/M techniques for the production of porous wicks have been shown capable of comfortably operating in flame temperatures in excess of 3000 K. Attention is presently given to Li corrosion tests conducted with Nb-10Hf-1Ti alloy heat pipes at up to 1477 K, in conjunction with the thermal performance data derived for specific heat-pipe designs. An Hf-rich reaction was detected after 200 hrs of exposure.

  11. Oxidized alginate hydrogels as niche environments for corneal epithelial cells

    PubMed Central

    Wright, Bernice; De Bank, Paul A; Luetchford, Kim A; Acosta, Fernando R; Connon, Che J

    2014-01-01

    Chemical and biochemical modification of hydrogels is one strategy to create physiological constructs that maintain cell function. The aim of this study was to apply oxidised alginate hydrogels as a basis for development of a biomimetic niche for limbal epithelial stem cells that may be applied to treating corneal dysfunction. The stem phenotype of bovine limbal epithelial cells (LEC) and the viability of corneal epithelial cells (CEC) were examined in oxidised alginate gels containing collagen IV over a 3-day culture period. Oxidation increased cell viability (P ≤ 0.05) and this improved further with addition of collagen IV (P ≤ 0.01). Oxidised gels presented larger internal pores (diameter: 0.2–0.8 µm) than unmodified gels (pore diameter: 0.05–0.1 µm) and were significantly less stiff (P ≤ 0.001), indicating that an increase in pore size and a decrease in stiffness contributed to improved cell viability. The diffusion of collagen IV from oxidised alginate gels was similar to that of unmodified gels suggesting that oxidation may not affect the retention of extracellular matrix proteins in alginate gels. These data demonstrate that oxidised alginate gels containing corneal extracellular matrix proteins can influence corneal epithelial cell function in a manner that may impact beneficially on corneal wound healing therapy. © 2013 The Authors. Journal of Biomedical Materials Research Part A Published byWiley Periodicals, Inc. Part A: 102A: 3393–3400, 2014. PMID:24142706

  12. Behavior of plutonium oxide particulates in a simulated Florida environment

    SciTech Connect

    Heaton, R.C.; Patterson, J.H.; Coffelt, K.P.

    1985-08-01

    The behavior of /sup 238/Pu oxide particles (20 to 74 ..mu..m in diameter) deposited on a soil surface was studied by using an environmental test chamber. The soil was obtained from Florida orange groves, and the chamber was set up to simulate a Florida climate. After more than 9 months and more than 60 simulated rainfalls, the plutonium oxide particles remained on top of the soil and showed no evidence of having moved down into the soil column. Plutonium was released into the soil drainages at the rate of 18 ng/m/sup 2//L. This release, which represents a minute portion of the source, appears to correlate with the volume of the drainage rather than with time and probably consists of plutonium attached to very fine soil particles. The average concentration of plutonium observed in the air was 7 fCi/L, which on an absolute basis, represents 8 x 10/sup -12/% of the source material. Thus the generation of airborne plutonium constitutes an insignificant release pathway in terms of the original source. However, the air concentration during, and especially at the beginning of, a rainfall was typically much higher (1400 fCi/L). This concentration decayed rapidly after the end of the rainfall. These results are compared with those from past experiments, and their implications are discussed.

  13. Oxidation behavior of V-Cr-Ti alloys in low-partial-pressure oxygen environments

    SciTech Connect

    Natesan, K.; Uz, M.

    1998-09-01

    A test program is in progress at Argonne National Laboratory to evaluate the effect of pO{sub 2} in the exposure environment on oxygen uptake, scaling kinetics, and scale microstructure in V-Cr-Ti alloys. The data indicate that the oxidation process follows parabolic kinetics in all of the environments used in the present study. From the weight change data, parabolic rate constants were evaluated as a function of temperature and exposure environment. The temperature dependence of the parabolic rate constants was described by an Arrhenius relationship. Activation energy for the oxidation process was fairly constant in the oxygen pressure range of 1 {times} 10{sup {minus}6} to 1 {times} 10{sup {minus}1} torr for both the alloys. The activation energy for oxidation in air was significantly lower than in low-pO{sub 2} environments, and for oxidation in pure O{sub 2} at 760 torr was much lower than in low-pO{sub 2} environments. X-ray diffraction analysis of the specimens showed that VO{sub 2} was the dominant phase in low-pO{sub 2} environments, while V{sub 2}O{sub 5} was dominant in air and in pure oxygen at 76f0 torr.

  14. Neutrophilic Iron-Oxidizing Microbes In The Marine Environment

    NASA Astrophysics Data System (ADS)

    Edwards, K. J.; Chan, C.; Orcutt, B.

    2007-12-01

    Neutrophilic iron-oxidizing bacteria (FeOB) have been recognized, described, enriched for and isolated from terrestrial aquatic and soil habitats for over one hundred years. Microbiologists and geoscientists alike have appreciated the important role FeOB play in processes such as corrosion and mineral deposition. However, recognition of their role and activities has lagged considerably behind in marine realms. Over approximately the past twenty years, however, there has been mounting interest and recognition of the presence and ubiquity of marine FeOB, particularly in the deep sea . Their role in rock and mineral weathering and alteration, mineral deposition, and biomass production in the deep sea has come into focus and is the subject of intense study. This paper will present an overview of marine FeOB including discussion of their habitats, diversity, and role in geochemical processes. In an effort to specifically target this elusive class of microbes, an observatory project for the study of FeOB and the marine microbial iron cycle has recently been launched--the Iron Microbial Observatory "FeMO", at the Loi'hi seamount, Hawaii. FeMO and FeOB isolated from Loi'hi are being used as model systems and testing grounds for studying mineral deposition and rock colonization in laboratory/field settings.

  15. Bioenergetic Analysis of the Anaerobic Oxidation of Methane in Diverse Biogeochemical Environments

    NASA Astrophysics Data System (ADS)

    Larowe, D.; Dale, A.; Regnier, P.

    2006-12-01

    The microorganisms responsible for the oxidation of methane in anoxic marine sediments constitute the largest sink of methane on Earth. It is generally accepted that the mechanism by which this process occurs involves a consortium of microbes that couple the reduction of sulfate to the oxidation of methane. However, whether this process occurs directly or through one of several reactive intermediate species such as hydrogen, acetate, and/or formate is a matter of debate. To better understand the biogeochemistry of the anaerobic oxidation of methane (AOM), we have calculated and compared the energetics of a number of candidate reactions that could supply AOM-microbial communities with enough energy to synthesize ATP in different environments. We present the results of thermodynamic computations quantifying the oxidation of methane to CO2 and H2, and, alternatively, to a variety of carbon species with intermediate nominal oxidation states. The potential role that these species have in the reduction of sulfate in three distinct organic-rich, anoxic sediment types is then investigated: 1) a shallow, coastal lagoon (Cape Lookout Bight, North Carolina, USA), 2) deep Black Sea sediments, and 3) a hydrothermal environment (Guaymas Basin, Gulf of California, Mexico). Furthermore, we compare the energetics of these reactions to the energy required to synthesize ATP from ADP and phosphate in situ. The results of these calculations can be used to better understand the temperature, pressure, and bulk compositional constraints on organisms responsible for oxidizing methane in anoxic environments.

  16. Tribochemistry of Carbon Films in Oxygen and Humid Environments: Oxidative Wear and Galvanic Corrosion.

    PubMed

    Alazizi, Ala; Draskovics, Andrew; Ramirez, Giovanni; Erdemir, Ali; Kim, Seong H

    2016-03-01

    The effects of oxidation on wear of carbon/steel tribological interfaces were studied. When mechanical wear was small, the oxidation behavior of hydrogenated diamond-like carbon (H-DLC) and stainless steel (SS) sliding interface varied depending on the nature of the oxidizing environment. In dry air or oxygen, both H-DLC and SS wore readily. The wear debris of SS did not form iron oxide in dry air and oxygen. In humid nitrogen, however, the wear of H-DLC diminished with increasing humidity, and the SS surface showed mild wear and iron oxide debris accumulated around the sliding contact region. These results revealed that different tribochemical reactions occur in dry oxygen and humid environments. In the absence of water, oxygen oxidizes the H-DLC surface, making it susceptible to wear, creating debris, and inducing wear on both H-DLC and SS. In contrast, adsorbed water molecules at less than 40% RH act as a molecular lubricant of the oxidized DLC surface, while multiwater layers adsorbed at near-saturation act as electrolyte inducing electrochemical galvanic corrosion reactions on the SS surface. When hydrogen-free amorphous carbon (a-C) was used in tribo-tests, severe wear of the SS surface occurs, in addition to the tribochemical wear observed for H-DLC, due to the high hardness of the a-C film. PMID:26844949

  17. Effect of environment on iodine oxidation state and reactivity with aluminum.

    PubMed

    Smith, Dylan K; McCollum, Jena; Pantoya, Michelle L

    2016-04-28

    Iodine oxide is a highly reactive solid oxidizer and with its abundant generation of iodine gas during reaction, this oxidizer also shows great potential as a biocidal agent. A problem with using I2O5 in an energetic mixture is its highly variable reactive behavior. This study isolates the variable reactivity associated with I2O5 as a function of its chemical reaction in various environments. Specifically, aluminum fuel and iodine oxide powder are combined using a carrier fluid to aid intermixing. The carrier fluid is shown to significantly affect the oxidation state of iodine oxide, thereby affecting the reactivity of the mixture. Four carrier fluids were investigated ranging in polarity and water miscibility in increasing order from hexane < acetone < isopropanol < water as well as untreated, dry-mixed reactants. Oxidation state and reactivity were examined with experimental techniques including X-ray photoelectric spectroscopy (XPS) and differential scanning calorimetry (DSC). Results are compared with thermal equilibrium simulations. Flame speeds increased with polarity of the fluid used to intermix the powder and ranged from 180 to 1202 m s(-1). The I2O5 processed in the polar fluids formed hydrated states of iodine oxide: HIO3 and HI3O8; and, the nonpolar and dry-mixed samples formed: I2O4 and I4O9. During combustion, the hydrated iodine oxides rapidly dehydrated from HIO3 to HI3O8 and from HI3O8 to I2O5. Both steps release 25% of their mass as vapor during combustion. Increased gas generation enhances convective energy transport and accounts for the increase in reactivity seen in the mixtures processed in polar fluids. These results explain the chemical mechanisms underlying the variable reactivity of I2O5 that are a function of the oxide's highly reactive nature with its surrounding environment. These results will significantly impact the selection of carrier fluid in the synthesis approach for iodine containing reactive mixtures. PMID:27052472

  18. Behavior Genetics of Aggression in Children: Review and Future Directions.

    ERIC Educational Resources Information Center

    DiLalla, Lisabeth Fisher

    2002-01-01

    Argues that a thorough understanding of factors that influence aggression in children cannot be achieved without including behavior genetic studies that allow examination of the effects of shared versus non-shared environment, as well as genes, on aggressive behaviors. Details the growing body of evidence on the genetic effects on aggression.…

  19. Oxidation and microstrucure of V-Cr-Ti alloys exposed to oxygen-containing environments

    SciTech Connect

    Natesan, K.; Uz, M.; Ulie, T.

    1997-08-01

    The objectives of this task are to (a) evaluate the oxygen uptake of several V-Cr-Ti alloys as a function of temperature and oxygen partial pressure in the exposure environment, (b) examine the microstructural characteristics of oxide scales and oxygen trapped at the grain boundaries in the substrate alloys, and (c) evaluate the influence of alloy composition on oxygen uptake and develop correlation(s) between alloy composition, exposure environment, and temperature.

  20. What Is Aggressive Violence?

    ERIC Educational Resources Information Center

    Singer, Dorothy G.; Luca, Wendy

    1985-01-01

    Responses to a questionnaire dealing with what constitutes aggressive violence on television indicate that health care providers tend to rate items describing acts on television as more aggressive than television writers, producers, and executives do. (MBR)

  1. Neurobiological Patterns of Aggression.

    ERIC Educational Resources Information Center

    Hunt, Robert D.

    1993-01-01

    Describes chemical model for patterns of aggressive behavior. Addresses cultural, neurobiological, and cognitive factors that affect violent children. Identifies five patterns of aggression (overaroused, impulsive, affective, predatory, and instrumental) and examines these dimensions of aggression for each pattern: baseline, precipitators,…

  2. Nickel aluminides and nickel-iron aluminides for use in oxidizing environments

    SciTech Connect

    Liu, C.T.

    1988-03-15

    A nickel aluminide is described consisting essentially of: a Ni/sub 3/Al base; a sufficient concentration of a Group IVB element or mixtures thereof to increase high temperature strength; a sufficient concentration of boron to increase ductility; and a sufficient concentration of chromium to increase ductility at elevated temperatures in oxidizing environments.

  3. Nickel aluminides and nickel-iron aluminides for use in oxidizing environments

    SciTech Connect

    Lui, C.T.

    1988-03-15

    This patent describes a nickel aluminide consisting essentially of: a Ni{sub 3}Al base; a sufficient concentration of a Group IVB element or mixtures thereof to increase high temperature strength; a sufficient concentration of boron to increase ductility; and a sufficient concentration of chromium to increase ductility at elevated temperatures in oxidizing environments.

  4. Relational aggression in marriage.

    PubMed

    Carroll, Jason S; Nelson, David A; Yorgason, Jeremy B; Harper, James M; Ashton, Ruth Hagmann; Jensen, Alexander C

    2010-01-01

    Drawing from developmental theories of relational aggression, this article reports on a study designed to identify if spouses use relationally aggressive tactics when dealing with conflict in their marriage and the association of these behaviors with marital outcomes. Using a sample of 336 married couples (672 spouses), results revealed that the majority of couples reported that relationally aggressive behaviors, such as social sabotage and love withdrawal, were a part of their marital dynamics, at least to some degree. Gender comparisons of partner reports of their spouse's behavior revealed that wives were significantly more likely to be relationally aggressive than husbands. Structural equation modeling demonstrated that relational aggression is associated with lower levels of marital quality and greater marital instability for both husbands and wives. Implications are drawn for the use of relational aggression theory in the future study of couple conflict and marital aggression. PMID:20698028

  5. Microbial Communities Associated with Biogenic Iron Oxide Mineralization in Circumneutral pH Environments

    NASA Astrophysics Data System (ADS)

    Chan, C. S.; Banfield, J. F.

    2002-12-01

    Lithotrophic growth on iron is a metabolism that has been found in a variety of neutral pH environments and is likely important in sustaining life in microaerophilic solutions, especially those low in organics. The composition of the microbial communities, especially the organisms that are responsible for iron oxidation, and carbon and nitrogen fixation, are not known, yet the ability to recognize these contributions is vital to our understanding of iron cycling in natural environments. Our approach has been to study the microbial community structure, mineralogy, and geochemistry of ~20 cm thick, 100's meters long, fluffy iron oxide-encrusted biological mats growing in the Piquette Mine tunnel, and to compare the results to those from geochemically similar environments. In situ measurements (Hydrolab) and geochemical characterization of bulk water samples and peepers (dialysis sampling vials) indicate that the environment is microaerobic, with micromolar levels of iron, high carbonate and sulfate, and typical groundwater nitrate and nitrite concentrations. 16S rDNA clone libraries show that the microbial mat and water contain communities with considerable diversity within the Bacterial domain, a large proportion of Nitrospira and Betaproteobacteria, and no Archaea. Because clone library data are not necessarily indicative of actual abundance, fluorescence in-situ hybridization (FISH) was performed on water, mat, and sediment samples from the Piquette mine and two circumneutral iron- and carbonate-rich springs in the Oregon Cascade Range. Domain- and phylum-level probes were chosen based on the clone library results (Nitrospira, Beta- and Gammaproteobacteria, Acidobacteria, Actinobacteria, Chloroflexi, and Planctomyces). FISH data reveal spatial associations between specific microbial groups and mineralized structures. The organisms responsible for making the mineralized sheaths that compose the bulk of the iron oxide mat are Betaproteobacteria (probably Leptothrix

  6. Reactive oxygen species accelerate degradation of anion exchange membranes based on polyphenylene oxide in alkaline environments.

    PubMed

    Parrondo, Javier; Wang, Zhongyang; Jung, Min-Suk J; Ramani, Vijay

    2016-07-20

    Anion exchange membranes (AEM) based on polyphenylene oxide (PPO) suffered quaternary-ammonium-cation-site degradation in alkaline environments. Surprisingly, the degradation rate was considerably faster in the presence of molecular oxygen. We postulated that the AEM cation-site catalyzes the reduction of dioxygen by hydroxide ions to yield the superoxide anion radical and the highly reactive hydroxyl free radical. We substantiated our hypothesis by using a phosphorous-containing spin trap (5-diisopropoxy-phosphoryl-5-methyl-1-pyrroline-N-oxide) to detect the adducts for both free radicals in situ using (31)P-NMR spectroscopy. PMID:27381009

  7. Hydrazines and carbohydrazides produced from oxidized carbon in earth's primitive environment

    NASA Technical Reports Server (NTRS)

    Folsome, C. E.; Brittain, A.; Smith, A.; Chang, S.

    1981-01-01

    Whether abiological organic compounds can be formed from the interactions of energy sources with nitrogen, oxidized carbon and water is held to be of importance in geochemical models of the primordial earth atmosphere. It is reported that experiments using quenched spark discharges through molecular nitrogen on aqueous suspensions of CaCO3 and other reactants to simulate the hydrosphere/atmosphere interface yield hydrazine and carbohydrazine in significant but low yields. Such reactions in primitive aquatic environments may have supplied a pathway for chemical evolution and the origin of life, on a primitive earth in which fully oxidized states of carbon were available for the primary synthesis of organic matter.

  8. Mycogenic Mn(II) oxidation promotes remediation of acid mine drainage and other anthropogenically impacted environments

    NASA Astrophysics Data System (ADS)

    Santelli, C. M.; Chaput, D.; Hansel, C. M.; Burgos, W. D.

    2014-12-01

    Manganese is a pollutant in worldwide environments contaminated with metals and organics, such as acid mine drainage (AMD), freshwater ponds, and agricultural waste storage sites. Microorganisms contribute to the removal of dissolved Mn compounds in the environment by promoting Mn(II) oxidation reactions. The oxidation of Mn(II) results in the precipitation of sparingly soluble Mn(IV) oxide minerals, effectively removing the metal from the aqueous milieu (e.g., groundwater or wastewater streams). In recent years, our research has identified a diversity of Mn(II)-oxidizing fungi inhabiting these polluted environments, however their overall contribution to the remediation process in situ remains poorly understood. Here we present results of culture-based and Next Generation Sequencing (NGS) studies in AMD treatment systems actively remediating Mn and other metals where we profile the bacterial, fungal, algal and archaeal communities to determine the overall community diversity and to establish the relative abundance of known Mn(II) oxidizers. A variety of treatment systems with varying Mn-removal efficiencies were sampled to understand the relationship between remediation efficiency and microbial community composition and activity. Targeted-amplicon sequencing of DNA and RNA of the 16S rRNA genes (bacteria and archaea), 23S rRNA genes (algae) and ITS region (fungi) was performed using both 454 pyrosequencing and Illumina platforms. Results showed that only the fungal taxonomic profiles significantly differed between sites that removed the majority of influent Mn and those that did not. Specifically, Ascomycota (which include known Mn(II) oxidizers isolated from these treatment systems) dominated greater efficiency systems whereas less efficient systems were dominated by Basidiomycota. Furthermore, known Mn(II) oxidizers accounted for only a minor proportion of bacterial sequences but a far greater proportion of fungal sequences. These culture-independent studies lend

  9. Authoritarianism and sexual aggression.

    PubMed

    Walker, W D; Rowe, R C; Quinsey, V L

    1993-11-01

    In Study 1, 198 men completed the Right Wing Authoritarianism, Sex Role Ideology, Hostility Towards Women, Acceptance of Interpersonal Violence, Adversarial Sexual Beliefs, and Rape Myth Acceptance scales, as well as measures of past sexually aggressive behavior and likelihood of future sexual aggression. As predicted, authoritarianism and sex role ideology were as closely related to self-reported past and potential future sexually aggressive behavior as were the specifically sexual and aggression-related predictors. Among 134 men in Study 2, authoritarianism and sex guilt positively correlated with each other and with self-reported past sexual aggression. In both studies, the relationship of authoritarianism and sexual aggression was larger in community than in university samples. PMID:8246111

  10. Isolation of microorganisms involved in reduction of crystalline iron(III) oxides in natural environments.

    PubMed

    Hori, Tomoyuki; Aoyagi, Tomo; Itoh, Hideomi; Narihiro, Takashi; Oikawa, Azusa; Suzuki, Kiyofumi; Ogata, Atsushi; Friedrich, Michael W; Conrad, Ralf; Kamagata, Yoichi

    2015-01-01

    Reduction of crystalline Fe(III) oxides is one of the most important electron sinks for organic compound oxidation in natural environments. Yet the limited number of isolates makes it difficult to understand the physiology and ecological impact of the microorganisms involved. Here, two-stage cultivation was implemented to selectively enrich and isolate crystalline iron(III) oxide reducing microorganisms in soils and sediments. Firstly, iron reducers were enriched and other untargeted eutrophs were depleted by 2-years successive culture on a crystalline ferric iron oxide (i.e., goethite, lepidocrocite, hematite, or magnetite) as electron acceptor. Fifty-eight out of 136 incubation conditions allowed the continued existence of microorganisms as confirmed by PCR amplification. High-throughput Illumina sequencing and clone library analysis based on 16S rRNA genes revealed that the enrichment cultures on each of the ferric iron oxides contained bacteria belonging to the Deltaproteobacteria (mainly Geobacteraceae), followed by Firmicutes and Chloroflexi, which also comprised most of the operational taxonomic units (OTUs) identified. Venn diagrams indicated that the core OTUs enriched with all of the iron oxides were dominant in the Geobacteraceae while each type of iron oxides supplemented selectively enriched specific OTUs in the other phylogenetic groups. Secondly, 38 enrichment cultures including novel microorganisms were transferred to soluble-iron(III) containing media in order to stimulate the proliferation of the enriched iron reducers. Through extinction dilution-culture and single colony isolation, six strains within the Deltaproteobacteria were finally obtained; five strains belonged to the genus Geobacter and one strain to Pelobacter. The 16S rRNA genes of these isolates were 94.8-98.1% identical in sequence to cultured relatives. All the isolates were able to grow on acetate and ferric iron but their physiological characteristics differed considerably in

  11. Scale formation on Ni-based alloys in simulated solid oxide fuel cell interconnect environments

    SciTech Connect

    Ziomek-Moroz, Margaret; Cramer, Stephen D.; Holcomb, Gordon R.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Singh, P.; Windisch, C.F.; Johnson, C.D.; Schaeffer, C.

    2004-11-01

    Recent publications suggest that the environment on the fuel side of the bi-polar stainless steel SOFC interconnects changes the oxidation behavior and morphology of the scale formed on the air side. The U.S. Department of Energy Albany Research Center (ARC), has examined the role of such exposure conditions on advanced nickel base alloys. Alloy formulations developed at ARC and commercial alloys were studied using X-ray diffraction (XRD) and Raman spectroscopy. The electrical property of oxide scales formed on selected alloys was determined in terms of areaspecific resistance (ASR). The corrosion behavior of ARC nickel-based alloys exposed to a dual environment of air/ H2 were compared to those of Crofer 22APU and Haynes 230.

  12. Oxidative stress in pied flycatcher (Ficedula hypoleuca) nestlings from metal contaminated environments in northern Sweden

    SciTech Connect

    Berglund, A.M.M. Sturve, J.; Foerlin, L.; Nyholm, N.E.I.

    2007-11-15

    Metals have been shown to induce oxidative stress in animals. One of the most metal polluted terrestrial environments in Sweden is the surroundings of a sulfide ore smelter plant located in the northern part of the country. Pied flycatcher nestlings (Ficedula hypoleuca) that grew up close to the industry had accumulated amounts of arsenic, cadmium, mercury, lead, iron and zinc in their liver tissue. The aim of this study was to investigate if pied flycatcher nestlings in the pollution gradient of the industry were affected by oxidative stress using antioxidant molecules and enzyme activities. The antioxidant assays were also evaluated in search for useful biomarkers in pied flycatchers. This study indicated that nestlings in metal contaminated areas showed signs of oxidative stress evidenced by up regulated hepatic antioxidant defense given as increased glutathione reductase (GR) and catalase (CAT) activities and slightly but not significantly elevated lipid peroxidation and glutathione-S-transferase (GST) activities. Stepwise linear regression indicated that lipid peroxidation and CAT activities were influenced mostly by iron, but iron and lead influenced the CAT activity to a higher degree. Positive relationships were found between GST and lead as well as GR activities and cadmium. We conclude that GR, CAT, GST activities and lipid peroxidation levels may function as useful biomarkers for oxidative stress in free-living pied flycatcher nestlings exposed to metal contaminated environments.

  13. An atomistic-based chemophysical environment for evaluating asphalt oxidation and antioxidants.

    PubMed

    Pan, Tongyan; Sun, Lu; Yu, Qifeng

    2012-12-01

    Asphalt binders in service conditions are subject to oxidative aging that involves the reactions between oxygen molecules and the component species of bulk asphalt. As a result, significant alterations can occur to the desired physical and/or mechanical properties of asphalt. A common practice to alleviate asphalt aging has been to employ different chemical additives or modifiers as antioxidants. The current state of knowledge in asphalt oxidation and antioxidant evaluation is centered on determining the degradation of asphalt physical properties, mainly the viscosity and ductility. Such practices, although meeting direct engineering needs, do not contribute to the fundamental understanding of the aging and anti-oxidation mechanisms, and thereby developing anti-aging strategies. From this standpoint, this study was initiated to study the chemical and physical bases of asphalt oxidation, as well as the anti-oxidation mechanisms of bio-based antioxidants using the coniferyl-alcohol lignin as an example. A quantum chemistry (QC) based chemophysical environment is developed, in which the various chemical reactions between asphalt component species and oxygen, as well as the incurred physical changes are studied. X-ray photoelectron spectroscopy (XPS) was used to validate the modified and unmodified asphalt models. PMID:22772829

  14. 40 CFR 13.10 - Aggressive collection actions; documentation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Aggressive collection actions; documentation. 13.10 Section 13.10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL CLAIMS COLLECTION STANDARDS Collection § 13.10 Aggressive collection actions; documentation. (a) EPA takes...

  15. Environmental Influences, the Developing Brain, and Aggressive Behavior

    ERIC Educational Resources Information Center

    Hudley, Cynthia; Novac, Andrei

    2007-01-01

    In this article the authors review research on highly stressful environments that are known to support the development and display of aggressive behavior in childhood, adolescence, and beyond. They also examine some of the mechanisms through which such stressful environments may influence adolescents' aggressive behavior. The review concentrates…

  16. Impairment of mitochondrial β-oxidation in rats under cold-hypoxic environment

    NASA Astrophysics Data System (ADS)

    Dutta, Arkadeb; Vats, Praveen; Singh, Vijay K.; Sharma, Yogendra K.; Singh, Som N.; Singh, Shashi B.

    2009-09-01

    Mitochondrial ß-oxidation of fatty acid provides a major source of energy in mammals. High altitude (HA), characterized by hypobaric hypoxia and low ambient temperatures, causes alteration in metabolic homeostasis. Several studies have depicted that hypoxic exposure in small mammals causes hypothermia due to hypometabolic state. Moreover, cold exposure along with hypoxia reduces hypoxia tolerance in animals. The present study investigated the rate of β-oxidation and key enzymes, carnitine palmitoyl transferase-I (CPT-I) and hydroxyacyl CoA dehydrogenase (HAD), in rats exposed to cold-hypobaric hypoxic environment. Male Sprague Dawley rats (190-220 g) were randomly divided into eight groups ( n = 6 rats in each group): 1 day hypoxia (H1); 7 days hypoxia (H7); 1 day cold (C1); 7 days cold (C7); 1 day cold-hypoxia (CH1); 7 days cold-hypoxia (CH7) exposed; and unexposed control for 1 and 7 days (UC1 and UC7). After exposure, animals were anaesthetized with ketamine (50 mg/kg body weight) and xylazine (10 mg/kg body weight) intraperitonialy and sacrificed. Mitochondrial CPT-I, HAD, 14C-palmitate oxidation in gastrocnemius muscle and liver, and plasma leptin were measured. Mitochondrial CPT-I was significantly reduced in muscle and liver in CH1 and CH7 as compared to respective controls. HAD activity was significantly reduced in H1 and CH7, and in H1, H7, CH1, and CH7 as compared to unexposed controls in muscle and liver, respectively. A concomitant decrease in 14C-palmitate oxidation was found. Significant reduction in plasma leptin in hypoxia and cold-hypoxia suggested hypometabolic state. It can be concluded that ß-oxidation of fatty acids is reduced in rats exposed to cold-hypoxic environment due to the persisting hypometabolic state in cold-hypoxia exposure.

  17. Girls' Aggressive Behavior

    ERIC Educational Resources Information Center

    Owens, Larry; Shute, Rosalyn; Slee, Phillip

    2004-01-01

    In contrast to boys' bullying behavior which is often overt and easily visible, girls' aggression is usually indirect and covert. Less research has been conducted on the types of bullying that girls usually engage in. Using focus groups composed of teenaged girls, Dr. Owens and colleagues examine the nature of teenage girls' indirect aggression.

  18. Aggression: Psychopharmacologic Management

    PubMed Central

    Conlon, Patrick; Frommhold, Kristine

    1989-01-01

    Aggression may be part of a variety of psychiatric diagnoses. The appropriate treatment requires that the physician recognize the underlying cause. Pharmacologic agents may form part of the overall treatment of the patient. The number of possible drugs for treating aggression has expanded rapidly, and it is important that the physician be familiar with the various options avilable. PMID:21248947

  19. Social Aggression among Girls.

    ERIC Educational Resources Information Center

    Underwood, Marion K.

    Noting recent interest in girls' social or "relational" aggression, this volume offers a balanced, scholarly analysis of scientific knowledge in this area. The book integrates current research on emotion regulation, gender, and peer relations, to examine how girls are socialized to experience and express anger and aggression from infancy through…

  20. Third Person Instigated Aggression.

    ERIC Educational Resources Information Center

    Gaebelein, Jacquelyn

    Since many acts of aggression in society are more than simply an aggressor-victim encounter, the role played by third person instigated aggression also needs examination. The purpose of this study was to develop a laboratory procedure to systematically investigate instigation. In a competitive reaction time task, high and low Machiavellian Males…

  1. Neuropsychiatry of Aggression

    PubMed Central

    Lane, Scott D.; Kjome, Kimberly L.; Moeller, F. Gerard

    2010-01-01

    Synopsis Aggression is a serious medical problem that can place both the patient and the health care provider at risk. Aggression can result from medical, neurologic and or psychiatric disorders. A comprehensive patient evaluation is needed. Treatment options include pharmacotherapy as well as non-pharmacologic interventions, both need to be individualized to the patient. PMID:21172570

  2. Tuning magnetic anisotropy by interfacially engineering the oxygen coordination environment in a transition metal oxide

    NASA Astrophysics Data System (ADS)

    Kan, Daisuke; Aso, Ryotaro; Sato, Riko; Haruta, Mitsutaka; Kurata, Hiroki; Shimakawa, Yuichi

    2016-04-01

    Strong correlations between electrons, spins and lattices--stemming from strong hybridization between transition metal d and oxygen p orbitals--are responsible for the functional properties of transition metal oxides. Artificial oxide heterostructures with chemically abrupt interfaces provide a platform for engineering bonding geometries that lead to emergent phenomena. Here we demonstrate the control of the oxygen coordination environment of the perovskite, SrRuO3, by heterostructuring it with Ca0.5Sr0.5TiO3 (0-4 monolayers thick) grown on a GdScO3 substrate. We found that a Ru-O-Ti bond angle of the SrRuO3 /Ca0.5Sr0.5TiO3 interface can be engineered by layer-by-layer control of the Ca0.5Sr0.5TiO3 layer thickness, and that the engineered Ru-O-Ti bond angle not only stabilizes a Ru-O-Ru bond angle never seen in bulk SrRuO3, but also tunes the magnetic anisotropy in the entire SrRuO3 layer. The results demonstrate that interface engineering of the oxygen coordination environment allows one to control additional degrees of freedom in functional oxide heterostructures.

  3. Geochemical modeling of arsenic sulfide oxidation kinetics in a mining environment

    NASA Astrophysics Data System (ADS)

    Lengke, Maggy F.; Tempel, Regina N.

    2005-01-01

    commonly mixed with sulfide minerals in a mining environment to prevent acid water formation. However, the oxidation rates of arsenic sulfides increase as solution pH rises and result in a greater release of As. Furthermore, the lifetimes of carbonate minerals (i.e., calcite, aragonite, and dolomite) are much shorter than those of arsenic sulfide and silicate minerals. Thus, within a geologic frame time, carbonate minerals may not be present to act as a pH buffer for acid mine waters. Additionally, the presence of silicate minerals such as pyroxenes (wollastonite, jadeite, and spodumene) and Ca-feldspars (labradorite, anorthite, and nepheline) may not be important for buffering acid solutions because these minerals dissolve faster than and have shorter lifetimes than sulfide minerals. However, other silicate minerals such as Na and K-feldspars (albite, sanidine, and microcline), quartz, pyroxenes (augite, enstatite, diopsite, and MnSiO 3) that have much longer lifetimes than arsenic sulfide minerals may be present in a system. The results of our modeling of arsenic sulfide mineral oxidation show that these minerals potentially can release significant concentrations of dissolved As to natural waters, and the factors and mechanisms involved in arsenic sulfide oxidation warrant further study.

  4. The local environment of Co2+ ions intercalated in vanadium oxide/hexadecylamine nanotubes

    NASA Astrophysics Data System (ADS)

    Saleta, M. E.; Aurelio, G.; Bardelli, F.; Sánchez, R. D.; Malta, M.; Torresi, R. M.

    2012-10-01

    Vanadium oxide nanotubes constitute promising materials for applications in nanoelectronics as cathode materials, in sensor technology and in catalysis. In this work we present a study on hybrid vanadium oxide/hexadecylamine multiwall nanotubes doped with Co ions using state of the art x-ray diffraction and absorption techniques, to address the issue of the dopant location within the nanotubes’ structure. The x-ray absorption near-edge structure analysis shows that the Co ions in the nanotubes are in the 2 + oxidation state, while extended x-ray absorption fine structure spectroscopy reveals the local environment of the Co2+ ions. Results indicate that Co atoms are exchanged at the interface between the vanadium oxide’s layers and the hexadecylamines, reducing the amount of amine chains and therefore the interlayer distance, but preserving the tubular shape. The findings in this work are important for describing Co2+ interaction with vanadium oxide nanotubes at the molecular level and will help to improve the understanding of their physicochemical behavior, which is desired in view of their promising applications.

  5. UV-B effects on leaves-Oxidative stress and acclimation in controlled environments.

    PubMed

    Czégény, Gyula; Mátai, Anikó; Hideg, Éva

    2016-07-01

    As the steady decline in the Earth's stratospheric ozone layer and parallel increase in solar ultraviolet-B (UV-B: 280-315nm) has come to an end, the focus of plant UV research has been shifted from regarding UV-B as threatening plant life to recognizing it as a regulatory factor. While UV-B photoreceptor mediated signaling is increasingly understood, the role of UV-B inducible reactive oxygen species is still to be explored. Earlier experiments with high UV-B irradiation doses and isolated thylakoid membranes demonstrated the potential of UV-B to trigger oxidative stress. However, under realistic UV conditions pro-oxidants cannot be reliably traced in more complex biological samples possessing an array of antioxidant defenses. In the absence of direct experimental evidence we must rely on indications and propose hypotheses on how and whether pro-oxidants, such as reactive oxygen species contribute to acclimative responses. Here we briefly review how a balance between pro-oxidants and antioxidants is affected by UV-B in whole plant experiments performed in controlled environments. A working hypothesis is proposed in which the extents of UV-induced peroxidase and superoxide dismutase activations affect the success of acclimation to UV-B. PMID:27181947

  6. Fabrication of Laser-reduced Graphene Oxide in Liquid Nitrogen Environment

    NASA Astrophysics Data System (ADS)

    Guan, Y. C.; Fang, Y. W.; Lim, G. C.; Zheng, H. Y.; Hong, M. H.

    2016-06-01

    Porous structure of reduced graphene oxide (rGO) plays an important role in developing flexible graphene-based devices. In this work, we report a novel methodology for reduction of freestanding graphite oxide (GO) sheet by picosecond pulse laser direct writing in liquid nitrogen. Non-agglomerate and porous structure of rGO is fabricated successfully due to frozen effect during laser processing. Compared with laser-irradiated rGO developed in N2 gas at ambient environment, the frozen rGO developed in liquid N2 shows better ordered structure with less defects, crack-free morphology as well as better electron supercapacitor performance including 50–60 Ω/sq in sheet electrical resistance. Mechanism of cryotemperature photoreduction GO is also discussed.

  7. Fabrication of Laser-reduced Graphene Oxide in Liquid Nitrogen Environment.

    PubMed

    Guan, Y C; Fang, Y W; Lim, G C; Zheng, H Y; Hong, M H

    2016-01-01

    Porous structure of reduced graphene oxide (rGO) plays an important role in developing flexible graphene-based devices. In this work, we report a novel methodology for reduction of freestanding graphite oxide (GO) sheet by picosecond pulse laser direct writing in liquid nitrogen. Non-agglomerate and porous structure of rGO is fabricated successfully due to frozen effect during laser processing. Compared with laser-irradiated rGO developed in N2 gas at ambient environment, the frozen rGO developed in liquid N2 shows better ordered structure with less defects, crack-free morphology as well as better electron supercapacitor performance including 50-60 Ω/sq in sheet electrical resistance. Mechanism of cryotemperature photoreduction GO is also discussed. PMID:27345474

  8. Fabrication of Laser-reduced Graphene Oxide in Liquid Nitrogen Environment

    PubMed Central

    Guan, Y. C.; Fang, Y. W.; Lim, G. C.; Zheng, H. Y.; Hong, M. H.

    2016-01-01

    Porous structure of reduced graphene oxide (rGO) plays an important role in developing flexible graphene-based devices. In this work, we report a novel methodology for reduction of freestanding graphite oxide (GO) sheet by picosecond pulse laser direct writing in liquid nitrogen. Non-agglomerate and porous structure of rGO is fabricated successfully due to frozen effect during laser processing. Compared with laser-irradiated rGO developed in N2 gas at ambient environment, the frozen rGO developed in liquid N2 shows better ordered structure with less defects, crack-free morphology as well as better electron supercapacitor performance including 50–60 Ω/sq in sheet electrical resistance. Mechanism of cryotemperature photoreduction GO is also discussed. PMID:27345474

  9. Isolation of microorganisms involved in reduction of crystalline iron(III) oxides in natural environments

    PubMed Central

    Hori, Tomoyuki; Aoyagi, Tomo; Itoh, Hideomi; Narihiro, Takashi; Oikawa, Azusa; Suzuki, Kiyofumi; Ogata, Atsushi; Friedrich, Michael W.; Conrad, Ralf; Kamagata, Yoichi

    2015-01-01

    Reduction of crystalline Fe(III) oxides is one of the most important electron sinks for organic compound oxidation in natural environments. Yet the limited number of isolates makes it difficult to understand the physiology and ecological impact of the microorganisms involved. Here, two-stage cultivation was implemented to selectively enrich and isolate crystalline iron(III) oxide reducing microorganisms in soils and sediments. Firstly, iron reducers were enriched and other untargeted eutrophs were depleted by 2-years successive culture on a crystalline ferric iron oxide (i.e., goethite, lepidocrocite, hematite, or magnetite) as electron acceptor. Fifty-eight out of 136 incubation conditions allowed the continued existence of microorganisms as confirmed by PCR amplification. High-throughput Illumina sequencing and clone library analysis based on 16S rRNA genes revealed that the enrichment cultures on each of the ferric iron oxides contained bacteria belonging to the Deltaproteobacteria (mainly Geobacteraceae), followed by Firmicutes and Chloroflexi, which also comprised most of the operational taxonomic units (OTUs) identified. Venn diagrams indicated that the core OTUs enriched with all of the iron oxides were dominant in the Geobacteraceae while each type of iron oxides supplemented selectively enriched specific OTUs in the other phylogenetic groups. Secondly, 38 enrichment cultures including novel microorganisms were transferred to soluble-iron(III) containing media in order to stimulate the proliferation of the enriched iron reducers. Through extinction dilution-culture and single colony isolation, six strains within the Deltaproteobacteria were finally obtained; five strains belonged to the genus Geobacter and one strain to Pelobacter. The 16S rRNA genes of these isolates were 94.8–98.1% identical in sequence to cultured relatives. All the isolates were able to grow on acetate and ferric iron but their physiological characteristics differed considerably in

  10. Surface modifications of steels to improve corrosion resistance in sulfidizing-oxidizing environments

    NASA Astrophysics Data System (ADS)

    Behrani, Vikas

    Industrial and power generation processes employ units like boilers and gasifiers to burn sulfur containing fuels to produce steam and syn gas (H 2 and CO), which can generate electricity using turbines and fuel cells. These units often operate under environments containing gases such as H 2S, SO2, O2 etc, which can attack the metallic structure and impose serious problems of corrosion. Corrosion control in high temperature sulfur bearing environments is a challenging problem requiring information on local gaseous species at the surface of alloy and mechanisms of degradation in these environments. Coatings have proved to be a better alternative for improving corrosion resistance without compromising the bulk mechanical properties. Changes in process conditions may result in thermal and/or environment cycling between oxidizing and sulfidizing environments at the alloy surface, which can damage the protective scale formed on the alloy surface, leading to increase in corrosion rates. Objective of this study was to understand the effect of fluctuating environments on corrosion kinetics of carbon steels and develop diffusion based coatings to mitigate the high temperatures corrosion under these conditions. More specifically, the focus was: (1) to characterize the local gaseous environments at the surface of alloys in boilers; (2) optimizing diffusion coatings parameters for carbon steel; (3) understand the underlying failure mechanisms in cyclic environments; (4) to improve aluminide coating behavior by co-deposition of reactive elements such as Yttrium and Hafnium; (5) to formulate a plausible mechanism of coating growth and effects of alloying elements on corrosion; and (6) to understand the spallation behavior of scale by measuring stresses in the scales. The understanding of coating mechanism and effects of fluctuating gaseous environments provides information for designing materials with more reliable performance. The study also investigates the mechanism behind

  11. Neural mediators of the intergenerational transmission of family aggression.

    PubMed

    Saxbe, Darby; Del Piero, Larissa Borofsky; Immordino-Yang, Mary Helen; Kaplan, Jonas Todd; Margolin, Gayla

    2016-05-01

    Youth exposed to family aggression may become more aggressive themselves, but the mechanisms of intergenerational transmission are understudied. In a longitudinal study, we found that adolescents' reduced neural activation when rating their parents' emotions, assessed via magnetic resonance imaging, mediated the association between parents' past aggression and adolescents' subsequent aggressive behavior toward parents. A subsample of 21 youth, drawn from the larger study, underwent magnetic resonance imaging scanning proximate to the second of two assessments of the family environment. At Time 1 (when youth were on average 15.51 years old) we measured parents' aggressive marital and parent-child conflict behaviors, and at Time 2 (≈2 years later), we measured youth aggression directed toward parents. Youth from more aggressive families showed relatively less activation to parent stimuli in brain areas associated with salience and socioemotional processing, including the insula and limbic structures. Activation patterns in these same areas were also associated with youths' subsequent parent-directed aggression. The association between parents' aggression and youths' subsequent parent-directed aggression was statistically mediated by signal change coefficients in the insula, right amygdala, thalamus, and putamen. These signal change coefficients were also positively associated with scores on a mentalizing measure. Hypoarousal of the emotional brain to family stimuli may support the intergenerational transmission of family aggression. PMID:26073067

  12. Neural mediators of the intergenerational transmission of family aggression

    PubMed Central

    Saxbe, Darby; Del Piero, Larissa Borofsky; Immordino-Yang, Mary Helen; Kaplan, Jonas Todd; Margolin, Gayla

    2015-01-01

    Youth exposed to family aggression may become more aggressive themselves, but the mechanisms of intergenerational transmission are understudied. In a longitudinal study, we found that adolescents’ reduced neural activation when rating their parents’ emotions, assessed via magnetic resonance imaging, mediated the association between parents’ past aggression and adolescents’ subsequent aggressive behavior toward parents. A subsample of 21 youth, drawn from the larger study, underwent magnetic resonance imaging scanning proximate to the second of two assessments of the family environment. At Time 1 (when youth were on average 15.51 years old) we measured parents’ aggressive marital and parent–child conflict behaviors, and at Time 2 (≈2 years later), we measured youth aggression directed toward parents. Youth from more aggressive families showed relatively less activation to parent stimuli in brain areas associated with salience and socioemotional processing, including the insula and limbic structures. Activation patterns in these same areas were also associated with youths’ subsequent parent-directed aggression. The association between parents’ aggression and youths’ subsequent parent-directed aggression was statistically mediated by signal change coefficients in the insula, right amygdala, thalamus, and putamen. These signal change coefficients were also positively associated with scores on a mentalizing measure. Hypoarousal of the emotional brain to family stimuli may support the intergenerational transmission of family aggression. PMID:26073067

  13. High temperature oxidation of HFPD thermal-sprayed MCrAlY coatings in simulated gas turbine environments

    NASA Astrophysics Data System (ADS)

    Belzunce, F. J.; Higuera, V.; Poveda, S.; Carriles, A.

    2002-12-01

    NiCrAlY and CoNiCrAlY powders were thermal-sprayed using the high frequency pulse detonation method (HFPD) onto AISI 310 austenitic stainless steel samples to obtain dense, adherent, high temperature oxidation resistant coatings. The oxidation behavior of both types of coatings in a 1000°C simulated gas turbine environment was experimentally determined. The porosity, hardness, coating thickness, and microstructure were not significantly modified by the high temperature oxidation cycles, but the internal oxidation increases significantly after a very low oxidation time. Surface phase composition was evaluated using x-ray diffraction (XRD) and scanning electron microscope (SEM) techniques, revealing the formation of a continuous and highly protective alumina layer. The oxidation kinetics of both coatings can be characterized by parabolic rate constants, which are very close to those for the formation of aluminum oxide on nickel or cobalt based alloys at similar conditions.

  14. Linkages between Aggression and Children's Legitimacy of Aggression Beliefs.

    ERIC Educational Resources Information Center

    Erdley, Cynthia A.; Asher, Steven R.

    To determine whether Slaby and Guerra's (1988) measure of aggression would reliably assess younger children's belief about aggression and whether children's belief about the legitimacy of aggression relates to their self-reports of it and to their levels of aggression as evaluated by peers, 781 fourth and fifth graders were asked to complete an…

  15. Aggressive Attitudes Predict Aggressive Behavior in Middle School Students.

    ERIC Educational Resources Information Center

    McConville, David W.; Cornell, Dewey G.

    2003-01-01

    This prospective study found that self-reported attitudes toward peer aggression among 403 middle school students were both internally consistent and stable over time (7 months). Aggressive attitudes were correlated with four outcome criteria for aggressive behavior: student self-report of peer aggression; peer and teacher nominations of bullying;…

  16. Aggression in Pretend Play and Aggressive Behavior in the Classroom

    ERIC Educational Resources Information Center

    Fehr, Karla K.; Russ, Sandra W.

    2013-01-01

    Research Findings: Pretend play is an essential part of child development and adjustment. However, parents, teachers, and researchers debate the function of aggression in pretend play. Different models of aggression predict that the expression of aggression in play could either increase or decrease actual aggressive behavior. The current study…

  17. An ultra-high temperature testing instrument under oxidation environment up to 1800 °C

    NASA Astrophysics Data System (ADS)

    Cheng, Xiangmeng; Qu, Zhaoliang; He, Rujie; Ai, Shigang; Zhang, Rubing; Pei, Yongmao; Fang, Daining

    2016-04-01

    A new testing instrument was developed to measure the high-temperature constitutive relation and strength of materials under an oxidative environment up to 1800 °C. A high temperature electric resistance furnace was designed to provide a uniform temperature environment for the mechanical testing, and the temperature could vary from room temperature (RT) to 1800 °C. A set of semi-connected grips was designed to reduce the stress. The deformation of the specimen gauge section was measured by a high temperature extensometer. The measured results were acceptable compared with the results from the strain gauge method. Meanwhile, tensile testing of alumina was carried out at RT and 800 °C, and the specimens showed brittle fracture as expected. The obtained Young's modulus was in agreement with the reported value. In addition, tensile experiment of ZrB2-20%SiC ceramic was conducted at 1700 °C and the high-temperature tensile stress-strain curve was first obtained. Large plastic deformation up to 0.46% and the necking phenomenon were observed before the fracture of specimen. This instrument will provide a powerful research tool to study the high temperature mechanical property of materials under oxidation and is benefit for the engineering application of materials in aerospace field.

  18. Sulfonamide antibiotic reduction in aquatic environment by application of fenton oxidation process

    PubMed Central

    2013-01-01

    Presence of antibiotics in the environment may cause potential risk for aquatic environment and organisms. In this research, Fenton oxidation process was offered as an effective method for removal of antibiotic sulfamethoxazole from aqueous solutions. The experiments were performed on laboratory-scale study under complete mixing at 25±2°C. The effects of initial antibiotic concentration, molar ratio of H2O2/Fe+2, solution pH, concentration of H2O2, Fe+2 and reaction time was studied on the oxidation of sulfamethoxazole in three level. The results indicated that the optimal parameters for Fenton process were as follows: molar ratio of [H2O2]/[Fe+2] = 1.5, pH= 4.5, and contact time= 15 min. In this situation, the antibiotic removal and COD reduction were achieved 99.99% and 64.7-70.67%, respectively. Although, Fenton reaction could effectively degrade antibiotic sulfamethoxazole under optimum experimental conditions, however, the rate of mineralization was not completed. This process can be considered to eliminate other refractory antibiotics with similar structure or to increase their biodegradability. PMID:23570238

  19. Bacterial methane oxidation in sea-floor gas hydrate: Significance to life in extreme environments

    SciTech Connect

    Sassen, R.; MacDonald, I.R.; Guinasso, N.L. Jr.; Requejo, A.G.; Sweet, S.T.; Alcala-Herrera, J.; DeFreitas, D.A.; Schink, D.R.; Joye, S.

    1998-09-01

    Samples of thermogenic hydrocarbon gases, from vents and gas hydrate mounds within a sea-floor chemosynthetic community on the Gulf of Mexico continental slope at about 540 m depth, were collected by research submersible. The study area is characterized by low water temperature (mean = 7 C), high pressure (about 5,400 kPa), and abundant structure II gas hydrate. Bacterial oxidation of hydrate-bound methane (CH{sub 4}) is indicated by three isotopic properties of gas hydrate samples. Relative to the vent gas from which the gas hydrate formed, (1) methane-bound methane is enriched in {sup 13}C by as much as 3.8% PDB (Peedee belemnite), (2) hydrate-bound methane is enriched in deuterium (D) by as much as 37% SMOW (standard mean ocean water), and (3) hydrate-bound carbon dioxide (CO{sub 2}) is depleted in {sup 13}C by as much as 22.4% PDB. Hydrate-associated authigenic carbonate rock is also depleted in {sup 13}C. Bacterial oxidation of methane is a driving force in chemosynthetic communities, and in the concomitant precipitation of authigenic carbonate rock that modifies sea-floor geology. Bacterial oxidation of hydrate-bound methane expands the potential boundaries of life in extreme environments.

  20. Simulation of RCC Crack Growth Due to Carbon Oxidation in High-Temperature Gas Environments

    NASA Technical Reports Server (NTRS)

    Titov, E. V.; Levin, D. A.; Picetti, Donald J.; Anderson, Brian P.

    2009-01-01

    The carbon wall oxidation technique coupled with a CFD technique was employed to study the flow in the expanding crack channel caused by the oxidation of the channel carbon walls. The recessing 3D surface morphing procedure was developed and tested in comparison with the arcjet experimental results. The multi-block structured adaptive meshing was used to model the computational domain changes due to the wall recession. Wall regression rates for a reinforced carbon-carbon (RCC) samples, that were tested in a high enthalpy arcjet environment, were computationally obtained and used to assess the channel expansion. The test geometry and flow conditions render the flow regime as the transitional to continuum, therefore Navier-Stokes gas dynamic approach with the temperature jump and velocity slip correction to the boundary conditions was used. The modeled mechanism for wall material loss was atomic oxygen reaction with bare carbon. The predicted channel growth was found to agree with arcjet observations. Local gas flow field results were found to affect the oxidation rate in a manner that cannot be predicted by previous mass loss correlations. The method holds promise for future modeling of materials gas-dynamic interactions for hypersonic flight.

  1. Physiological plasticity of the thermophilic ammonia oxidizing archaeon Nitrosocaldus yellowstonii in response to a changing environment

    NASA Astrophysics Data System (ADS)

    Jewell, T.; Johnson, A.; Gelsinger, D.; de la Torre, J. R.

    2012-12-01

    Our understanding of nitrogen biogeochemical cycling in high temperature environments underwent a dramatic revision with the discovery of ammonia oxidizing archaea (AOA). The importance of AOA to the global nitrogen cycle came to light when recent studies of marine AOA demonstrated the dominance of these organisms in the ocean microbiome and their role as producers of the greenhouse gas nitrous oxide (N2O). Understanding how AOA respond to fluctuating environments is crucial to fully comprehending their contribution to global biogeochemical cycling and climate change. In this study we use the thermophilic AOA Nitrosocaldus yellowstonii strain HL72 to explore the physiological plasticity of energy metabolism in these organisms. Previous studies have shown that HL72 grows autotrophically by aerobically oxidizing ammonia (NH3) to nitrite (NO2-). Unlike studies of marine AOA, we find that HL72 can grow over a wide ammonia concentration range (0.25 - 10 mM NH4Cl) with comparable generation times when in the presence of 0.25 to 4 mM NH4Cl. However, preliminary data indicate that amoA, the alpha subunit of ammonia monooxygenase (AMO), is upregulated at low ammonia concentrations (<50 μM) compared to growth at 1 mM. Although the ammonia oxidation pathway has not been fully elucidated, we have shown that nitric oxide (NO) appears to be a key intermediate: exponentially growing HL72 produces significant NO and the removal of NO using a scavenger reversibly inhibits growth. In addition to AMO, the HL72 genome also contains sequences for a urease encoded by subunits ureABC and an active urea transporter. Urea ((NH2)2CO) is an organic compound ubiquitous to aquatic and soil habitats that, when hydrolyzed, forms NH3 and CO2. We examined urea as an alternate source of ammonia for the ammonia oxidation pathway. HL72 grows over a wide range of urea concentrations (0.25 - 10 mM) at rates comparable to growth on ammonia. In a substrate competition experiment HL72 preferentially

  2. Hydrogen Peroxide Cycling in Acidic Geothermal Environments and Potential Implications for Oxidative Stress

    NASA Astrophysics Data System (ADS)

    Mesle, M.; Beam, J.; Jay, Z.; Bodle, B.; Bogenschutz, E.; Inskeep, W.

    2014-12-01

    Hydrogen peroxide (H2O2) may be produced in natural waters via photochemical reactions between dissolved oxygen, organic carbon and light. Other reactive oxygen species (ROS) such as superoxide and hydroxyl radicals are potentially formed in environments with high concentrations of ferrous iron (Fe(II), ~10-100 μM) by reaction between H2O2 and Fe(II) (i.e., Fenton chemistry). Thermophilic archaea and bacteria inhabiting acidic iron-oxide mats have defense mechanisms against both extracellular and intracellular peroxide, such as peroxiredoxins (which can degrade H2O2) and against other ROS, such as superoxide dismutases. Biological cycling of H2O2 is not well understood in geothermal ecosystems, and geochemical measurements combined with molecular investigations will contribute to our understanding of microbial response to oxidative stress. We measured H2O2 and other dissolved compounds (Fe(II), Fe(III), H2S, O2), as well as photon flux, pH and temperature, over time in surface geothermal waters of several acidic springs in Norris Geyser Basin, Yellowstone National Park, WY (Beowulf Spring and One Hundred Spring Plain). Iron-oxide mats were sampled in Beowulf Spring for on-going analysis of metatranscriptomes and RT-qPCR assays of specific stress-response gene transcription (e.g., superoxide dismutases, peroxiredoxins, thioredoxins, and peroxidases). In situ analyses show that H2O2 concentrations are lowest in the source waters of sulfidic systems (ca. 1 μM), and increase by two-fold in oxygenated waters corresponding to Fe(III)-oxide mat formation (ca. 2 - 3 μM). Channel transects confirm increases in H2O2 as a function of oxygenation (distance). The temporal dynamics of H2O2, O2, Fe(II), and H2S in Beowulf geothermal waters were also measured during a diel cycle, and increases in H2O2 were observed during peak photon flux. These results suggest that photochemical reactions may contribute to changes in H2O2. We hypothesize that increases in H2O2 and O2

  3. Behavioral and Pharmacogenetics of Aggressive Behavior

    PubMed Central

    Takahashi, Aki; Quadros, Isabel M.; de Almeida, Rosa M. M.; Miczek, Klaus A.

    2013-01-01

    Serotonin (5-HT) has long been considered as a key transmitter in the neurocircuitry controlling aggression. Impaired regulation of each subtype of 5-HT receptor, 5-HT transporter, synthetic and metabolic enzymes has been linked particularly to impulsive aggression. The current summary focuses mostly on recent findings from pharmacological and genetic studies. The pharmacological treatments and genetic manipulations or polymorphisms of a specific target (e.g., 5-HT1A receptor) can often result in inconsistent results on aggression, due to “phasic” effects of pharmacological agents vs “trait”-like effects of genetic manipulations. Also, the local administration of a drug using the intracranial microinjection technique has shown that activation of specific subtypes of 5-HT receptors (5-HT1A and 5-HT1B) in mesocorticolimbic areas can reduce species-typical and other aggressive behaviors, but the same receptors in the medial prefrontal cortex or septal area promote escalated forms of aggression. Thus, there are receptor populations in specific brain regions that preferentially modulate specific types of aggression. Genetic studies have shown important gene × environment interactions; it is likely that the polymorphisms in the genes of 5-HT transporters (e.g., MAO A) or rate-limiting synthetic and metabolic enzymes of 5-HT determine the vulnerability to adverse environmental factors that escalate aggression. We also discuss the interaction between the 5-HT system and other systems. Modulation of 5-HT neurons in the dorsal raphe nucleus by GABA, glutamate, and CRF profoundly regulate aggressive behaviors. Also, interactions of the 5-HT system with other neuropeptides (arginine vasopressin, oxytocin, neuropeptide Y, opioid) have emerged as important neurobiological determinants of aggression. Studies of aggression in genetically modified mice identified several molecules that affect the 5-HT system directly (e.g., Tph2, 5-HT1B, 5-HT transporter, Pet1, MAOA) or

  4. Applicability of the polyphenylene oxide film dosimeter to high UV exposures in aquatic environments.

    PubMed

    Schouten, P W; Parisi, A V; Turnbull, D J

    2009-09-01

    Previous research has proven that the Poly (2,6-dimethyl-1, 4-phenylene oxide) (PPO) dosimeter is capable of receiving both in-air and underwater UV exposures that are significantly greater than those of the more commonly used polysulphone dosimeter, within a range of accuracy close to what would be expected of dosimetric measurements made in-air provided that the necessary calibrations are completed correctly by factoring in different atmospheric column ozone levels, SZA ranges, varying water turbidity and DOM levels. However, there is yet to be an investigation detailing the performance of the PPO dosimeter and its ability to measure UV in an actual field environment over an extended period of time. This research aims to bridge this gap in the knowledge by presenting a measurement campaign carried out in two real world aquatic environments and a simulated sea water environment using a batch of PPO dosimeters set at different depths and aligned to a range of different angles and geographical directions by means of attachment to a custom built dosimeter submersible float (DSF) unit over the space of a year at a sub-tropical location. Results obtained from this measurement campaign were used to compute a K(d) value for the sea water in each particular season. These K(d) values where found to be in close agreement to standalone K(d) values derived from results taken using a standard calibrated spectrometer in the same sea water. PMID:19596202

  5. Examining Genetic and Environmental Effects on Reactive versus Proactive Aggression

    ERIC Educational Resources Information Center

    Brendgen, Mara; Vitaro, Frank; Boivin, Michel; Dionne, Ginette; Perusse, Daniel

    2006-01-01

    This study compared the contribution of genes and environment to teacher-rated reactive and proactive aggression in 6-year-old twin pairs (172 pairs: 55 monozygotic girls, 48 monozygotic boys, 33 dizygotic girls, 36 dizygotic boys). Genetic effects accounted for 39% of the variance of reactive aggression and for 41% of the variance of proactive…

  6. Controlling Aggressive Students. Fastback Series, No. 387.

    ERIC Educational Resources Information Center

    Blendinger, Jack; And Others

    Coping with aggressive student behavior is crucial to providing a safe and orderly classroom and school environment. Approaches for improving student behavior, ranging from enhancing a student's interpersonal skills to restraint techniques (such as the prudent use of physical force) are covered in this booklet. The material blends information in…

  7. Etiological Distinctions between Aggressive and Non-Aggressive Antisocial Behavior: Results from a Nuclear Twin Family Model

    ERIC Educational Resources Information Center

    Burt, S. Alexandra; Klump, Kelly L.

    2012-01-01

    A recent meta-analysis of 103 studies Burt ("Clinical Psychology Review," 29:163-178, 2009a) highlighted the presence of etiological distinctions between aggressive (AGG) and non-aggressive rule-breaking (RB) dimensions of antisocial behavior, such that AGG was more heritable than was RB, whereas RB was more influenced by the shared environment.…

  8. Adolescents’ Aggression to Parents: Longitudinal Links with Parents’ Physical Aggression

    PubMed Central

    Margolin, Gayla; Baucom, Brian R.

    2014-01-01

    Purpose To investigate whether parents’ previous physical aggression (PPA) exhibited during early adolescence is associated with adolescents’ subsequent parent-directed aggression even beyond parents’ concurrent physical aggression (CPA); to investigate whether adolescents’ emotion dysregulation and attitudes condoning child-to-parent aggression moderate associations. Methods Adolescents (N = 93) and their parents participated in a prospective, longitudinal study. Adolescents and parents reported at waves 1–3 on four types of parents’ PPA (mother-to-adolescent, father-to-adolescent, mother-to-father, father-to-mother). Wave 3 assessments also included adolescents’ emotion dysregulation, attitudes condoning aggression, and externalizing behaviors. At waves 4 and 5, adolescents and parents reported on adolescents’ parent-directed physical aggression, property damage, and verbal aggression, and on parents’ CPA Results Parents’ PPA emerged as a significant indicator of adolescents’ parent-directed physical aggression (odds ratio [OR]: 1.25, 95% confidence interval [CI]: 1.0–1.55; p = .047), property damage (OR: 1.29, 95% CI: 1.1–1.5, p = .002), and verbal aggression (OR: 1.35, 95% CI: 1.15–1.6, p < .001) even controlling for adolescents’ sex, externalizing behaviors, and family income. When controlling for parents’ CPA, previous mother-to-adolescent aggression still predicted adolescents’ parent-directed physical aggression (OR: 5.56, 95% CI: 1.82–17.0, p = .003), and father-to-mother aggression predicted adolescents’ parent-directed verbal aggression (OR: 1.86, 95% CI: 1.0–3.3, p = .036). Emotion dysregulation and attitudes condoning aggression did not produce direct or moderated effects. Conclusions Adolescents’ parent-directed aggression deserves greater attention in discourse about lasting, adverse effects of even minor forms of parents’ physical aggression. Future research should investigate parent-directed aggression as

  9. Corrosion properties of oxide dispersion strengthened steels in super-critical water environment

    NASA Astrophysics Data System (ADS)

    Cho, H. S.; Kimura, A.; Ukai, S.; Fujiwara, M.

    2004-08-01

    The effects of alloying elements on corrosion resistance in super critical pressurized water (SCPW) have been investigated to develop corrosion resistant oxide dispersion strengthened (ODS) steels. Corrosion tests were performed in a SCPW (783 K, 25 MPa) environment. Weight gain was measured after exposure to the SCPW. For the improvement of corrosion-resistance, the effects of chromium, aluminum, and yttrium on the corrosion behavior were investigated. The 9-12 wt%Cr ODS steels showed almost similar corrosion behavior with the ordinary ferritic/martensitic steel in the SCPW. However, the addition of high chromium (>13 wt%) and aluminum (4.5 wt%) are very effective to suppress the corrosion in the SCPW. Anodic polarization experiments revealed that the passive current of the ODS steels are lower than the ordinary ferritic/martensitic steels. Addition of aluminum improves the Charpy impact property of the ODS steels.

  10. Aggregation and resuspension of graphene oxide in simulated natural surface aquatic environments.

    PubMed

    Hua, Zulin; Tang, Zhiqiang; Bai, Xue; Zhang, Jianan; Yu, Lu; Cheng, Haomiao

    2015-10-01

    A series of experiments were performed to simulate the environmental behavior and fate of graphene oxide nanoparticles (GONPs) involved in the surface environment relating to divalent cations, natural organic matter (NOM), and hydraulics. The electrokinetic properties and hydrodynamic diameters of GONPs was systematically determined to characterize GONPs stability and the results indicated Ca(2+) (Mg(2+)) significantly destabilized GONPs with high aggregate strength factors (SF) and fractal dimension (FD), whereas NOM decreased aggregate SF with lower FD and improved GONPs stability primarily because of increasing steric repulsion and electrostatic repulsion. Furthermore, the GONPs resuspension from the sand bed into overlying water with shear flow confirmed that the release would be restricted by Ca(2+) (Mg(2+)), however, enhanced by NOM. The interaction energy based on Derjaguin-Landau-Verwey-Overbeek theory verifies the aggregation and resuspension well. Overall, these experiments provide an innovative look and more details to study the behavior and fate of GONPs. PMID:26071942

  11. Photocatalytic: oxidation of volatile organic compounds present in airborne environment adjacent to sewage treatment plants.

    PubMed

    Raillard, C; Héquet, V; Le Cloirec, P; Legrand, J

    2004-01-01

    Emissions of volatile organic compounds (VOCs) from wastewater in municipal sewage or industrial wastewater treatment plants are often overlooked as sources of exposure to hazardous substances. The impact of such emissions on local airborne environments represents a growing source of scientific, toxicological and public health interest. Actually, VOCs are suspected to be quite dangerous for human health. Some of them belong to the family of odorous compounds and can cause serious annoyance in the neighbourhood of the emission sources. A way to remove VOCs released from sewers and wastewater treatment facilities could be to degrade them by photocatalytic oxidation. TiO2-based photocatalysts are known to be efficient for this kind of application. In the present work TiO2 P25 Degussa was deposited on glass supports. These materials were tested for the degradation of butanone-2 in a photocatalytic reactor. The influence of water vapour (relative humidity) was shown using the Langmuir-Hinshelwood kinetic model. PMID:14979545

  12. Investigation of the oxidation behavior of dispersion stabilized alloys when exposed to a dynamic high temperature environment

    NASA Technical Reports Server (NTRS)

    Tenney, D. R.

    1974-01-01

    The oxidation behavior of TD-NiCr and TD-NiCrAlY alloys have been studied at 2000 and 2200 F in static and high speed flowing air environments. The TD-NiCrAlY alloys preoxidized to produce an Al2O3 scale on the surface showed good oxidation resistance in both types of environments. The TD-NiCr alloy which had a Cr2O3 oxide scale after preoxidation was found to oxidize more than an order of magnitude faster under the dynamic test conditions than at comparable static test conditions. Although Cr2O3 normally provides good oxidation protection, it was rapidly lost due to formation of volatile CrO3 when exposed to the high speed air stream. The preferred oxide arrangement for the dynamic test consisted of an external layer of NiO with a porous mushroom type morphology, an intermediate duplex layer of NiO and Cr2O3, and a continuous inner layer of Cr2O3 in contact with the alloy substrate. An oxidation model has been developed to explain the observed microstructure and overall oxidation behavior of all alloys.

  13. The Effect on Aggression of Variation in Amount of Opportunity for Play. (Internal Report).

    ERIC Educational Resources Information Center

    Wuellner, Lance

    The effect of a high-opportunity (HO) versus a low-opportunity (LO) play environment on the aggression of preschool children was investigated, hypothesizing that the LO play environment will elicit significantly more aggression than the HO play environment. The two environments were presented randomly to one group of 10 4-year-olds, five of each…

  14. Anaerobic methane oxidation coupled to nitrite reduction can be a potential methane sink in coastal environments.

    PubMed

    Shen, Li-Dong; Hu, Bao-Lan; Liu, Shuai; Chai, Xiao-Ping; He, Zhan-Fei; Ren, Hong-Xing; Liu, Yan; Geng, Sha; Wang, Wei; Tang, Jing-Liang; Wang, Yi-Ming; Lou, Li-Ping; Xu, Xiang-Yang; Zheng, Ping

    2016-08-01

    In the current study, we investigated nitrite-dependent anaerobic methane oxidation (N-DAMO) as a potential methane sink in the Hangzhou Bay and the adjacent Zhoushan sea area. The potential activity of the N-DAMO process was primarily observed in Hangzhou Bay by means of (13)C-labeling experiments, whereas very low or no potential N-DAMO activity could be detected in the Zhoushan sea area. The measured potential N-DAMO rates ranged from 0.2 to 1.3 nmol (13)CO2 g(-1) (dry sediment) day(-1), and the N-DAMO potentially contributed 2.0-9.4 % to the total microbial methane oxidation in the examined sediments. This indicated that the N-DAMO process may be an alternative pathway in the coastal methane cycle. Phylogenetic analyses confirmed the presence of Candidatus Methylomirabilis oxyfera-like bacteria in all the examined sediments, while the group A members (the dominant bacteria responsible for N-DAMO) were found mainly in Hangzhou Bay. Quantitative PCR showed that the 16S rRNA gene abundance of Candidatus M. oxyfera-like bacteria varied from 5.4 × 10(6) to 5.0 × 10(7) copies g(-1) (dry sediment), with a higher abundance observed in Hangzhou Bay. In addition, the overlying water NO3 (-) concentration and salinity were identified as the most important factors influencing the abundance and potential activity of Candidatus M. oxyfera-like bacteria in the examined sediments. This study showed the evidence of N-DAMO in coastal environments and indicated the importance of N-DAMO as a potential methane sink in coastal environments. PMID:27225473

  15. Disturbance of ion environment and immune regulation following biodistribution of magnetic iron oxide nanoparticles injected intravenously.

    PubMed

    Park, Eun-Jung; Kim, Sang-Wook; Yoon, Cheolho; Kim, Younghun; Kim, Jong Sung

    2016-01-22

    Although it is expected that accumulation of metal oxide nanoparticles that can induce redox reaction in the biological system may influence ion homeostasis and immune regulation through generation of free radicals, the relationship is still unclear. In this study, mice received magnetic iron oxide nanoparticles (M-FeNPs, 2 and 4 mg/kg) a single via the tail vein, and their distribution in tissues was investigated over time (1, 4, and 13 weeks). In addition, we evaluated the effects on homeostasis of redox reaction-related elements, the ion environment and immune regulation. The iron level in tissues reached at the maximum on 4 weeks after injection and M-FeNPs the most distributed in the spleen at 13 weeks. Additionally, levels of redox reaction-related elements in tissues were notably altered since 1 week post-injection. While levels of K(+) and Na(+) in tissue tended to decrease with time, Ca(2+) levels reached to the maximum at 4 weeks post-injection. On 13 weeks post-injection, the increased percentages of neutrophils and eosinophils, the enhanced release of LDH, and the elevated secretion of IL-8 and IL-6 were clearly observed in the blood of M-FeNP-treated mice compared to the control. While expression of antigen presentation related-proteins and the maturation of dendritic cells were markedly inhibited following distribution of M-FeNPs, the expression of several chemokines, including CXCR2, CCR5, and CD123, was enhanced on the splenocytes of the treated groups. Taken together, we suggest that accumulation of M-FeNPs may induce adverse health effects by disturbing homeostasis of the immune regulation and ion environment. PMID:26687879

  16. Complete genome sequence of Nitrosospira multiformis, an ammonia-oxidizing bacterium from the soil environment.

    PubMed

    Norton, Jeanette M; Klotz, Martin G; Stein, Lisa Y; Arp, Daniel J; Bottomley, Peter J; Chain, Patrick S G; Hauser, Loren J; Land, Miriam L; Larimer, Frank W; Shin, Maria W; Starkenburg, Shawn R

    2008-06-01

    The complete genome of the ammonia-oxidizing bacterium Nitrosospira multiformis (ATCC 25196(T)) consists of a circular chromosome and three small plasmids totaling 3,234,309 bp and encoding 2,827 putative proteins. Of the 2,827 putative proteins, 2,026 proteins have predicted functions and 801 are without conserved functional domains, yet 747 of these have similarity to other predicted proteins in databases. Gene homologs from Nitrosomonas europaea and Nitrosomonas eutropha were the best match for 42% of the predicted genes in N. multiformis. The N. multiformis genome contains three nearly identical copies of amo and hao gene clusters as large repeats. The features of N. multiformis that distinguish it from N. europaea include the presence of gene clusters encoding urease and hydrogenase, a ribulose-bisphosphate carboxylase/oxygenase-encoding operon of distinctive structure and phylogeny, and a relatively small complement of genes related to Fe acquisition. Systems for synthesis of a pyoverdine-like siderophore and for acyl-homoserine lactone were unique to N. multiformis among the sequenced genomes of ammonia-oxidizing bacteria. Gene clusters encoding proteins associated with outer membrane and cell envelope functions, including transporters, porins, exopolysaccharide synthesis, capsule formation, and protein sorting/export, were abundant. Numerous sensory transduction and response regulator gene systems directed toward sensing of the extracellular environment are described. Gene clusters for glycogen, polyphosphate, and cyanophycin storage and utilization were identified, providing mechanisms for meeting energy requirements under substrate-limited conditions. The genome of N. multiformis encodes the core pathways for chemolithoautotrophy along with adaptations for surface growth and survival in soil environments. PMID:18390676

  17. Microbiology of aggressive periodontitis.

    PubMed

    Könönen, Eija; Müller, Hans-Peter

    2014-06-01

    For decades, Aggregatibacter actinomycetemcomitans has been considered the most likely etiologic agent in aggressive periodontitis. Implementation of DNA-based microbiologic methodologies has considerably improved our understanding of the composition of subgingival biofilms, and advanced open-ended molecular techniques even allow for genome mapping of the whole bacterial spectrum in a sample and characterization of both the cultivable and not-yet-cultivable microbiota associated with periodontal health and disease. Currently, A. actinomycetemcomitans is regarded as a minor component of the resident oral microbiota and as an opportunistic pathogen in some individuals. Its specific JP2 clone, however, shows properties of a true exogenous pathogen and has an important role in the development of aggressive periodontitis in certain populations. Still, limited data exist on the impact of other microbes specifically in aggressive periodontitis. Despite a wide heterogeneity of bacteria, especially in subgingival samples collected from patients, bacteria of the red complex in particular, and those of the orange complex, are considered as potential pathogens in generalized aggressive periodontitis. These types of bacterial findings closely resemble those found for chronic periodontitis, representing a mixed polymicrobial infection without a clear association with any specific microorganism. In aggressive periodontitis, the role of novel and not-yet-cultivable bacteria has not yet been elucidated. There are geographic and ethnic differences in the carriage of periodontitis-associated microorganisms, and they need to be taken into account when comparing study reports on periodontal microbiology in different study populations. In the present review, we provide an overview on the colonization of potential periodontal pathogens in childhood and adolescence, and on specific microorganisms that have been suspected for their role in the initiation and progression of aggressive

  18. Environmental factors determining ammonia-oxidizing organism distribution and diversity in marine environments.

    PubMed

    Bouskill, Nicholas J; Eveillard, Damien; Chien, Diana; Jayakumar, Amal; Ward, Bess B

    2012-03-01

    Ammonia-oxidizing bacteria (AOB) and archaea (AOA) play a vital role in bridging the input of fixed nitrogen, through N-fixation and remineralization, to its loss by denitrification and anammox. Yet the major environmental factors determining AOB and AOA population dynamics are little understood, despite both groups having a wide environmental distribution. This study examined the relative abundance of both groups of ammonia-oxidizing organisms (AOO) and the diversity of AOA across large-scale gradients in temperature, salinity and substrate concentration and dissolved oxygen. The relative abundance of AOB and AOA varied across environments, with AOB dominating in the freshwater region of the Chesapeake Bay and AOA more abundant in the water column of the coastal and open ocean. The highest abundance of the AOA amoA gene was recorded in the oxygen minimum zones (OMZs) of the Eastern Tropical South Pacific (ETSP) and the Arabian Sea (AS). The ratio of AOA : AOB varied from 0.7 in the Chesapeake Bay to 1600 in the Sargasso Sea. Relative abundance of both groups strongly correlated with ammonium concentrations. AOA diversity, as determined by phylogenetic analysis of clone library sequences and archetype analysis from a functional gene DNA microarray, detected broad phylogenetic differences across the study sites. However, phylogenetic diversity within physicochemically congruent stations was more similar than would be expected by chance. This suggests that the prevailing geochemistry, rather than localized dispersal, is the major driving factor determining OTU distribution. PMID:22050634

  19. The oxidative environment: a mediator of interspecies communication that drives symbiosis evolution

    PubMed Central

    Moné, Yves; Monnin, David; Kremer, Natacha

    2014-01-01

    Symbiotic interactions are ubiquitous in nature and play a major role in driving the evolution of life. Interactions between partners are often mediated by shared signalling pathways, which strongly influence both partners' biology and the evolution of the association in various environments. As an example of ‘common language’, the regulation of the oxidative environment plays an important role in driving the evolution of symbiotic associations. Such processes have been occurring for billions of years, including the increase in Earth's atmospheric oxygen and the subsequent evolution of mitochondria. The effect of reactive oxygen species and reactive nitrogen species (RONS) has been characterized functionally, but the molecular dialogue between partners has not been integrated within a broader evolutionary context yet. Given the pleiotropic role of RONS in cell–cell communication, development and immunity, but also their associated physiological costs, we discuss here how their regulation can influence the establishment, the maintenance and the breakdown of various symbiotic associations. By synthesizing recent developments in redox biology, we aim to provide an interdisciplinary understanding of the influence of such mediators of interspecies communication on the evolution and stability of symbioses, which in turn can shape ecosystems and play a role in health and disease. PMID:24807248

  20. A Tale of Two Oxidation States: Bacterial Colonization of Arsenic-Rich Environments

    PubMed Central

    Muller, Daniel; Médigue, Claudine; Koechler, Sandrine; Barbe, Valérie; Barakat, Mohamed; Talla, Emmanuel; Bonnefoy, Violaine; Krin, Evelyne; Arsène-Ploetze, Florence; Carapito, Christine; Chandler, Michael; Cournoyer, Benoît; Cruveiller, Stéphane; Dossat, Caroline; Duval, Simon; Heymann, Michael; Leize, Emmanuelle; Lieutaud, Aurélie; Lièvremont, Didier; Makita, Yuko; Mangenot, Sophie; Nitschke, Wolfgang; Ortet, Philippe; Perdrial, Nicolas; Schoepp, Barbara; Siguier, Patricia; Simeonova, Diliana D; Rouy, Zoé; Segurens, Béatrice; Turlin, Evelyne; Vallenet, David; Dorsselaer, Alain Van; Weiss, Stéphanie; Weissenbach, Jean; Lett, Marie-Claire; Danchin, Antoine; Bertin, Philippe N

    2007-01-01

    Microbial biotransformations have a major impact on contamination by toxic elements, which threatens public health in developing and industrial countries. Finding a means of preserving natural environments—including ground and surface waters—from arsenic constitutes a major challenge facing modern society. Although this metalloid is ubiquitous on Earth, thus far no bacterium thriving in arsenic-contaminated environments has been fully characterized. In-depth exploration of the genome of the β-proteobacterium Herminiimonas arsenicoxydans with regard to physiology, genetics, and proteomics, revealed that it possesses heretofore unsuspected mechanisms for coping with arsenic. Aside from multiple biochemical processes such as arsenic oxidation, reduction, and efflux, H. arsenicoxydans also exhibits positive chemotaxis and motility towards arsenic and metalloid scavenging by exopolysaccharides. These observations demonstrate the existence of a novel strategy to efficiently colonize arsenic-rich environments, which extends beyond oxidoreduction reactions. Such a microbial mechanism of detoxification, which is possibly exploitable for bioremediation applications of contaminated sites, may have played a crucial role in the occupation of ancient ecological niches on earth. PMID:17432936

  1. Oxygen as Intermediate in Anoxic Environments: Nitrite-Dependent Methane Oxidation and Beyond

    NASA Astrophysics Data System (ADS)

    Ettwig, K. F.

    2014-12-01

    In recent years the known diversity of hydrocarbon activation mechanisms under anaerobic conditions has been extended by intra-aerobic denitrification, a process in which oxygen is derived from NO and used for substrate activation. For two phylogenetically unrelated bacterial species, the freshwater NC10 phylum bacterium Methylomirabilis oxyfera [1] and the marine γ-proteobacterial strain HdN1 [2] it has been shown that, under anoxic conditions with nitrate and/or nitrite, mono-oxygenases are used for methane and hexadecane oxidation, respectively. No degradation was observed with nitrous oxide (N2O) only. In the anaerobic methanotroph M. oxyfera, which lacks apparent nitrous oxide reductase in its genome, substrate activation in the presence of nitrite was directly associated with both O2 and N2 formation. These findings strongly argue for the role of nitric oxide (NO), or an oxygen species derived from it, in the activation reaction of methane. Although intracellular oxygen generation has been experimentally documented and elegantly explains the utilization of 'aerobic' pathways under anoxic conditions, research about the underlying molecular mechanism has just started. The proposed candidate enzymes for oxygen (or possibly another another reactive intermediate) production from NO, an NO dismutase (NOD) [3], related to quinol-dependent NO reductases (qNORs), is present and highly expressed in both M. oxyfera and strain HdN1. Besides that, several recently sequenced species from the Cytophaga-Flavobacterium-Bacteroides group harbor Nod/Nor genes, but experimential evidence is needed to show if these have NOD activity, are unusual but functional qNORs, or represent transition states between the two. Additionally, for several anaerobic hydrocarbon-degrading organisms the biochemical mechanism of substrate activation has not been elucidated yet: whereas signature genes of anaerobic degradation are missing, monooxygenase genes are present. Also these microorganisms

  2. Characterization and exposure measurement for indium oxide nanofibers generated as byproducts in the LED manufacturing environment.

    PubMed

    Choi, Kwang-Min; An, Hee-Chul

    2016-01-01

    This article aimed to elucidate the physicochemical characteristics and exposure concentration of powder and airborne particles as byproducts generated from indium tin oxide thin film process by an electron beam evaporation method during maintenance in light-emitting diode manufacturing environment. The chemical composition, size, shape, and crystal structure of powder and airborne particles as byproducts were investigated using a scanning electron microscope equipped with energy dispersive spectrometer, and an X-ray diffractometer. The number and mass concentration measurements of airborne particles were performed by using an optical particle counter of direct-reading aerosol monitor and an inductively coupled plasma-mass spectrometry after sampling, respectively. The airborne particles are composed of oxygen and indium. On the other hand, the powder byproducts consist mostly of oxygen and indium, but tin was found as a minor component. The shapes of the airborne and powder byproducts were fiber type. The length and diameter of fibrous particles were approximately 500-2,000 nm and 30-50 nm, respectively. The powder byproducts indicated indium oxide nanofibers with a rhombohedral structure. On the other hand, the indium oxide used as a source material in the preparation of ITO target showed spherical morphology with a body-centered cubic structure, and it was the same as that of the pure crystalline indium oxide powder. During maintenance, the number concentrations ranged from 350-75,693 particles/ft(3), and arithmetic mean±standard deviation and geometric mean±geometric standard deviation were 11,624±15,547 and 4,846±4.12 particles/ft(3), respectively. Meanwhile, under the same conditions, the airborne mass concentrations of the indium based on respirable particle size (3.5 µm cut-point 50%) were 0.09-0.19 µg/m(3). Physicochemical characteristics of nanoparticle can affect toxicity so the fact that shape and crystal structure have changed is important. Thus

  3. Hydrogen Therapy Reduces Oxidative Stress-associated Risks Following Acute and Chronic Exposure to High-altitude Environment.

    PubMed

    Shi, Qing Hai; Wei, Wei; Ran, Ji Hua; Wang, Si Yuan; Liu, Zheng Xiang; Ge, Di; Chen, Ping; Fu, Jian Feng

    2015-03-01

    Low pressure, low oxygen concentration, and intense ultraviolet (UV) radiation in high-altitude environments, can cause oxidative stress which can trigger mountain sickness. A recent study demonstrated that hydrogen gas with a good permeability in biological membranes can treat various disorders by exerting its selective anti-oxidation and anti-inflammatory effects, indicating that hydrogen therapy plays a role in scavenging free radicals and in balancing oxidation and anti-oxidation systems of cells. Therefore, we hypothesize that inhaling low-dose hydrogen or drinking hydrogen-saturated water is a novel and simple method to prevent and treat oxidative stress injury caused by low pressure, low oxygen concentration and intense UV radiation in plateaus, thus reducing the risk of mountain sickness. PMID:25800452

  4. Analysis of the Metal Oxide Space Clouds (MOSC) HF Propagation Environment

    NASA Astrophysics Data System (ADS)

    Jackson-Booth, N.; Selzer, L.

    2015-12-01

    Artificial Ionospheric Modification (AIM) attempts to modify the ionosphere in order to alter the high frequency (HF) propagation environment. It can be achieved through injections of aerosols, chemicals or radio (RF) signals into the ionosphere. The Metal Oxide Space Clouds (MOSC) experiment was undertaken in April/May 2013 to investigate chemical AIM. Two sounding rockets were launched from the Kwajalein Atoll (part of the Marshall Islands) and each released a cloud of vaporized samarium (Sm). The samarium created a localized plasma cloud, with increased electron density, which formed an additional ionospheric layer. The ionospheric effects were measured by a wide range of ground based instrumentation which included a network of high frequency (HF) sounders. Chirp transmissions were made from three atolls and received at five sites within the Marshall Islands. One of the receive sites consisted of an 18 antenna phased array, which was used for direction finding. The ionograms have shown that as well as generating a new layer the clouds created anomalous RF propagation paths, which interact with both the cloud and the F-layer, resulting in 'ghost traces'. To fully understand the propagation environment a 3D numerical ray trace has been undertaken, using a variety of background ionospheric and cloud models, to find the paths through the electron density grid for a given fan of elevation and azimuth firing angles. Synthetic ionograms were then produced using the ratio of ray path length to speed of light as an estimation of the delay between transmission and observation for a given frequency of radio wave. This paper reports on the latest analysis of the MOSC propagation environment, comparing theory with observations, to further understanding of AIM.

  5. Intellectual Competence and Aggression.

    ERIC Educational Resources Information Center

    Huesmann, L. Rowell; Yarmel, Patty Warnick

    Using data from a broader longitudinal study, this investigation explores within-subject and cross-generational stability of intellectual competence and the relationship of such stability to aggressive behavior. Data were gathered three times (when subjects' modal age was 8, 19, and 30 years). Initially, subjects included the entire population…

  6. Relational Aggression among Students

    ERIC Educational Resources Information Center

    Young, Ellie L.; Nelson, David A.; Hottle, America B.; Warburton, Brittney; Young, Bryan K.

    2011-01-01

    "Relational aggression" refers to harm within relationships caused by covert bullying or manipulative behavior. Examples include isolating a youth from his or her group of friends (social exclusion), threatening to stop talking to a friend (the silent treatment), or spreading gossip and rumors by email. This type of bullying tends to be…

  7. Stability of Aggressive Behavior.

    ERIC Educational Resources Information Center

    Eron, Leonard D.; Huesmann, L. Rowell

    As indicated by multiple measures (including overt criminal behavior), stability of aggressive behavior was investigated across 22 years for males and females in a variety of situations. Originally, subjects included the entire population enrolled in the third grade in a semi-rural county in New York State. The sample included approximately 870…

  8. Human Aggression and Suicide

    ERIC Educational Resources Information Center

    Brown, Gerald L.; Goodwin, Frederick K

    1986-01-01

    The central nervous system transmitter serontonin may be altered in aggressive/impulsive and suicidal behaviors in humans. These reports are largely consistent with animal data, and constitute one of the most highly replicated set of findings in biological psychiatry. Suggests that some suicidal behavior may be a special kind of aggressive…

  9. Anonymity, Deindividuation and Aggression.

    ERIC Educational Resources Information Center

    Baron, Robert S.

    Several writers suggest that reducing one's sense of individuality reduces social restraints. The author suggests that the effect of uniformity of appearance on aggression is unclear when anonymity is held constant. This poses a problem of interpretation given that a distinction must be made between lack of individuality and anonymity. One must…

  10. Parents' Aggressive Influences and Children's Aggressive Problem Solutions with Peers

    ERIC Educational Resources Information Center

    Duman, Sarah; Margolin, Gayla

    2007-01-01

    This study examined children's aggressive and assertive solutions to hypothetical peer scenarios in relation to parents' responses to similar hypothetical social scenarios and parents' actual marital aggression. The study included 118 children ages 9 to 10 years old and their mothers and fathers. Children's aggressive solutions correlated with…

  11. Relational Aggression and Physical Aggression among Adolescent Cook Islands Students

    ERIC Educational Resources Information Center

    Page, Angela; Smith, Lisa F.

    2016-01-01

    Both physical and relational aggression are characterised by the intent to harm another. Physical aggression includes direct behaviours such as hitting or kicking; relational aggression involves behaviours designed to damage relationships, such as excluding others, spreading rumours, and delivering threats and verbal abuse. This study extended…

  12. Status Struggles: Network Centrality and Gender Segregation in Same- and Cross-Gender Aggression

    ERIC Educational Resources Information Center

    Faris, Robert; Felmlee, Diane

    2011-01-01

    Literature on aggression often suggests that individual deficiencies, such as social incompetence, psychological difficulties, or troublesome home environments, are responsible for aggressive behavior. In this article, by contrast, we examine aggression from a social network perspective, arguing that social network centrality, our primary measure…

  13. Reverse Discrimination and Aggressive Behavior.

    ERIC Educational Resources Information Center

    Johnson, Stephen D.

    1980-01-01

    White subjects were aggressive toward Black opponents when contest results appeared to reflect elements of reverse discrimination; but they showed less aggressive behavior toward Black opponents when they thought their loss was due to their opponents' superior ability. (RL)

  14. Coping with Agitation and Aggression

    MedlinePlus

    Alzheimer ’s Caregiving Tips Coping with Agitation and Aggression People with Alzheimer’s disease may become agitated or aggressive as the disease gets worse. Agitation means that a person is restless or worried. ...

  15. Molecular phylogeny of type II methane-oxidizing bacteria isolated from various environments.

    PubMed

    Heyer, Jürgen; Galchenko, Valery F; Dunfield, Peter F

    2002-09-01

    Type II methane-oxidizing bacteria (MOB) were isolated from diverse environments, including rice paddies, pristine and polluted freshwaters and sediments, mangrove roots, upland soils, brackish water ecosystems, moors, oil wells, water purification systems and livestock manure. Isolates were identified based on morphological traits as either Methylocystis spp., Methylosinus sporium or Methylosinus trichosporium. Molecular phylogenies were constructed based on nearly complete 16S rRNA gene sequences, and on partial sequences of genes encoding PmoA (a subunit of particulate methane monooxygenase), MxaF (a subunit of methanol dehydrogenase) and MmoX (a subunit of soluble methane monooxygenase). The maximum pairwise 16S rDNA difference between isolates was 4.2%, and considerable variability was evident within the Methylocystis (maximum difference 3.6%). Due to this variability, some of the published 'specific' oligonucleotide primers for type II MOB exhibit multiple mismatches with gene sequences from some isolates. The phylogenetic tree constructed from pmoA gene sequences closely mirrored that constructed from 16S rDNA sequences, and both supported the presently accepted taxonomy of type II MOB. Contrary to previously published phylogenetic trees, morphologically distinguishable species were generally monophyletic based on pmoA or 16S rRNA gene sequences. This was not true for phylogenies constructed from mmoX and mxaF gene sequences. The phylogeny of mxaF gene sequences suggested that horizontal transfer of this gene may have occurred across type II MOB species. Soluble methane monooxygenase could not be detected in many Methylocystis strains either by an enzyme activity test (oxidation of naphthalene) or by PCR-based amplification of an mmoX gene. PMID:12213929

  16. Serotonin and Aggressiveness in Chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Serotonin (5-HT) regulates aggressive behavior in animals. This study examined if 5-HT regulation of aggressiveness is gene-dependent. Chickens from two divergently selected lines KGB and MBB (Kind Gentle Birds and Mean Bad Birds displaying low and high aggressiveness, respectively) and DXL (Dekalb ...

  17. Conducting oxide formation and mechanical endurance of potential solid-oxide fuel cell interconnects in coal syngas environment

    SciTech Connect

    Liu, Kejia; Luo, Junhang; Johnson, Christopher; Liu, Xingbo; Lang, J.; Mao, S.X.

    2008-08-15

    The oxidation properties of potential SOFCs materials Crofer 22 APU, Ebrite and Haynes 230 exposed in coal syngas at 800 °C for 100 h were studied. The phases and surface morphology of the oxide scales were characterized by X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray analysis (EDX). The mechanical endurance and electrical resistance of the conducting oxides were characterized by indentation and electrical impedance, respectively. It was found that the syngas exposure caused the alloys to form porous oxide scales, which increased the electrical resistant and decreased the mechanical stability. As for short-term exposure in syngas, neither carbide nor metal dusting was found in the scales of all samples.

  18. Conducting oxide formation and mechanical endurance of potential solid-oxide fuel cell interconnects in coal syngas environment

    NASA Astrophysics Data System (ADS)

    Liu, Kejia; Luo, Junhang; Johnson, Chris; Liu, Xingbo; Yang, J.; Mao, Scott X.

    The oxidation properties of potential SOFCs materials Crofer 22 APU, Ebrite and Haynes 230 exposed in coal syngas at 800 °C for 100 h were studied. The phases and surface morphology of the oxide scales were characterized by X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray analysis (EDX). The mechanical endurance and electrical resistance of the conducting oxides were characterized by indentation and electrical impedance, respectively. It was found that the syngas exposure caused the alloys to form porous oxide scales, which increased the electrical resistant and decreased the mechanical stability. As for short-term exposure in syngas, neither carbide nor metal dusting was found in the scales of all samples.

  19. Clinical association of baseline levels of conjugated dienes in low-density lipoprotein and nitric oxide with aggressive B-cell non-Hodgkin lymphoma and their relationship with immunoglobulins and Th1-to-Th2 ratio

    PubMed Central

    Haddouche, Mustapha; Meziane, Warda; Hadjidj, Zeyneb; Mesli, Naima; Aribi, Mourad

    2016-01-01

    Objective The aim of this study was to highlight the clinical association of baseline levels of conjugated dienes in low-density lipoprotein (LDL-BCD) and nitric oxide (NO) with immunoglobulins (Igs) and T helper (Th)1/Th2 ratio in patients with newly diagnosed B-cell non-Hodgkin lymphoma (NHL). Patients and methods Thirty-two newly diagnosed patients with aggressive B-cell NHL and 25 age-, sex-, and body-mass-index-matched healthy controls were randomly selected for a cross-sectional case–control study conducted at the Hematology Department of Tlemcen Medical Centre University (northwest of Algeria). Results Circulating levels of LDL-BCD and NO and those of IgA and IgM were significantly higher in patients than in controls. The levels of Th1/Th2 ratio and plasma total antioxidant capacity were significantly lower in patients compared with controls, while malondialdehyde and protein carbonyl levels were significantly higher in patients. B-cell NHL was significantly associated with high levels of LDL-BCD from 25th to 75th percentile (25th percentile: relative risk [RR] =2.26, 95% confidence interval [CI] 1.42–3.59, P=0.014; 50th percentile: RR =2.84, 95% CI 1.72–4.68, P<0.001; 75th percentile: RR =5.43, 95% CI 2.58–11.42, P<0.001). Similarly, the disease was significantly associated with high levels of NO production from 25th to 75th percentile (25th percentile: RR =2.07, 95% CI 1.25–3.44, P=0.024; 50th percentile: RR =2.78, 95% CI 1.63–4.72, P<0.001; 75th percentile: RR =4.68, 95% CI 2.21–9.91, P<0.001). Moreover, LDL-BCD levels were positively and significantly correlated with interferon (IFN)-γ, whereas NO levels were inversely and significantly correlated with IFN-γ and Th1/Th2 ratio. Conclusion LDL-BCD and NO production seem to be associated with aggressive B-cell NHL and alteration of Th1/Th2 ratio. Our results have to be examined using ex vivo mechanistic studies leading to further investigations of these parameters, with an interest in the

  20. Children's normative beliefs about aggression and aggressive behavior.

    PubMed

    Huesmann, L R; Guerra, N G

    1997-02-01

    Normative beliefs have been defined as self-regulating beliefs about the appropriateness of social behaviors. In 2 studies the authors revised their scale for assessing normative beliefs about aggression, found that it is reliable and valid for use with elementary school children, and investigated the longitudinal relation between normative beliefs about aggression and aggressive behavior in a large sample of elementary school children living in poor urban neighborhoods. Using data obtained in 2 waves of observations 1 year apart, the authors found that children tended to approve more of aggression as they grew older and that this increase appeared to be correlated with increases in aggressive behavior. More important, although individual differences in aggressive behavior predicted subsequent differences in normative beliefs in younger children, individual differences in aggressive behavior were predicted by preceding differences in normative beliefs in older children. PMID:9107008

  1. Oxidation of dissolved iron under warmer, wetter conditions on Mars: Transitions to present-day arid environments

    NASA Technical Reports Server (NTRS)

    Burns, R. G.

    1993-01-01

    The copious deposits of ferric-iron assemblages littering the surface of bright regions of Mars indicate that efficient oxidative weathering reactions have taken place during the evolution of the planet. Because the kinetics of atmosphere-surface (gas-solid) reactions are considerably slower than chemical weathering reactions involving an aqueous medium, most of the oxidation products now present in the martian regolith probably formed when groundwater flowed near the surface. This paper examines how chemical weathering reactions were effected by climatic variations when warm, wet environments became arid on Mars. Analogies are drawn with hydrogeochemical and weathering environments on the Australian continent where present-day oxidation of iron is occurring in acidic ground water under arid conditions.

  2. Oxidation characteristics of 440 C CRES in gaseous oxygen (GOX) environments. [Corrosion Resistant Steel

    SciTech Connect

    Dennies, D.P.; Parsons, T.D.

    1986-10-01

    The oxidation characteristics of 440 C corrosion-resistant steel are evaluated. The dependence of oxide color, type, and thickness, material hardness, and microstructure on temperature is examined. The effects of exposure time, passivation layer, and oxygen pressure on the oxide formation are investigated. A direct relationship between temperature and oxide color, formation, and thickness is detected. It is observed that the exposure time does not affect the microstructure or oxide color, type, or thickness; however, the passivation layer does affect oxide color and type. 9 references.

  3. Oxidation characteristics of 440 C CRES in gaseous oxygen (GOX) environments. [Corrosion Resistant Steel

    NASA Technical Reports Server (NTRS)

    Dennies, Daniel P.; Parsons, Terry D.

    1986-01-01

    The oxidation characteristics of 440 C corrosion-resistant steel are evaluated. The dependence of oxide color, type, and thickness, material hardness, and microstructure on temperature is examined. The effects of exposure time, passivation layer, and oxygen pressure on the oxide formation are investigated. A direct relationship between temperature and oxide color, formation, and thickness is detected. It is observed that the exposure time does not affect the microstructure or oxide color, type, or thickness; however, the passivation layer does affect oxide color and type.

  4. Thermal Properties and Structural Stability of LaCoO3 in Reducing and Oxidizing Environments

    SciTech Connect

    Radovic, Miladin; Speakman, Scott A; Allard Jr, Lawrence Frederick; Payzant, E Andrew; Lara-Curzio, Edgar; Kriven, Waltraud M; Lloyd, John; Fegely, Laura C; Orlovskaya, Nina

    2008-09-01

    Thermal expansion of LaCoO3 perovskite in air and 4% H2/96% Ar reducing atmosphere has been studied by Thermal Mechanical Analysis (TMA). The thermal behavior of LaCoO3 in air exhibits a non-linear expansion in 100 400 C temperature range. A significant increase of CTE measured in air both during heating and cooling experiments occurs in the 200 250 C temperature range, corresponding to a known spin state transition. LaCoO3 is found to be unstable in a reducing atmosphere. It undergoes a series of expansion and contractions due to phase transformations beginning around 500 C with very intensive chemical/phase changes at 850oC and above. These expansions and contractions are directly related to the formation of La3Co3O8, La2CoO4, La4Co3O10, La2O3, CoO, and other Co compounds due to the reducing atmosphere. Although LaCoO3 is a good ionic and electronic conductor and catalyst, its high thermal expansion as well structural instability in reducing environments presents a serious restriction for its application in solid oxide fuel cells, sensors or gas separation membranes.

  5. Neutron diffraction studies of nickel-containing perovskite oxide catalysts exposed to autothermal reforming environments.

    SciTech Connect

    Mawdsley, J. R.; Vaughey, J. T.; Krause, T. R.; Chemical Sciences and Engineering Division

    2009-10-27

    Six nickel-containing perovskite oxides (La{sub 1-x}Sr{sub x})M{sub 0.9}Ni{sub 0.1}O{sub 3{+-}{delta}}, where x = 0 or 0.2 and M = Cr, Fe, or Mn were used to catalyze the autothermal reforming of isooctane (C{sub 8}H{sub 18}) into a hydrogen-rich gas during short-term tests at 700 C. To determine the phase stability of the samples in the reducing environment of the reforming reactor, characterization studies of the as-prepared and tested perovskite samples were conducted using powder X-ray diffraction, powder neutron diffraction, transmission electron microscopy, and scanning electron microscopy. We determined that the reducing conditions of the microreactor caused metallic nickel to form in all six compositions. However, the extent of the nickel loss from the perovskite lattices varied: the chromium-containing compositions lost the least nickel, compared to the manganese- and iron-containing compositions, and the strontium-free compositions lost more nickel than their strontium-containing analogs. Five of the six perovskite compositions tested showed no breakdown of the perovskite lattice despite the loss of nickel from the B-sites, producing only the third example of a B-cation-deficient, 3d transition-metal-containing perovskite.

  6. High Temperature Oxidation of Silicon Carbide and Advanced Iron-Based Alloys in Steam-Hydrogen Environments

    SciTech Connect

    Terrani, Kurt A; Keiser, James R; Brady, Michael P; Cheng, Ting; Silva, G W Chinthaka M; Pint, Bruce A; Snead, Lance Lewis

    2012-01-01

    A side by side comparison of the oxidation behavior of zirconium alloys with SiC materials and advanced iron-based alloys is provided. Oxidation tests were conducted in steam and steam-hydrogen environments at 800-1350 C and 0.34-2MPa for durations up to 48 hours. Monolithic SiC specimens as well as SiC/SiC composites were examined during the study where the material recession mechanism appeared to be governed by silica layer volatilization at the surface for CVD SiC. A wide set of austenitic and ferritic steels were also examined where a critical Cr content (>20 wt.%) was shown to be necessary to achieve oxidation resistance at high temperatures. SiC materials and alumina-forming ferritic steels exhibited slowest oxidation kinetics; roughly two orders of magnitude lower than zirconium alloys.

  7. Foraging in an oxidative environment: relationship between δ13C values and oxidative status in Adélie penguins

    PubMed Central

    Beaulieu, Michaël; Ropert-Coudert, Yan; Le Maho, Yvon; Ancel, André; Criscuolo, François

    2010-01-01

    The alternation of short/coastal and long/pelagic foraging trips has been proposed as a strategy for seabirds to reconcile self-feeding and parental care. Both types of foraging trips may result in different foraging efforts and diet qualities, and consequently are likely to modify the oxidative status of seabirds. We examined the relationship between the oxidative status of Adélie penguins and (i) the duration of their foraging trips and (ii) their plasma δ13C values reflecting their spatial distribution. The oxidative status did not correlate with the foraging trip duration but with the δ13C values: high values being associated with high levels of oxidative damage. This relationship is likely to be related to the prey properties of penguins as both parameters are largely determined by the diet. Two non-exclusive hypotheses can be proposed to explain this relationship: (i) penguins foraging in coastal areas feed on a diet enriched in 13C and depleted in antioxidant compounds; (ii) birds with low antioxidant capacity are constrained to forage in coastal areas. Our study is the first to show that the adoption of different foraging strategies is associated with different levels of oxidative stress. However, further studies are needed to investigate the underlying mechanisms of this intriguing relationship. PMID:19955151

  8. Oxidation behavior of grain boundary engineered alloy 690 in supercritical water environment

    NASA Astrophysics Data System (ADS)

    Xu, P.; Zhao, L. Y.; Sridharan, K.; Allen, T. R.

    2012-03-01

    Nickel-base alloy is an important structural material that is known for its exceptional high temperature oxidation resistance. Oxidation in this alloy at high temperatures occurs to a greater extent along the grain boundaries. Grain boundary engineering (GBE) was applied to modify the grain boundary characteristics of this alloy to affect its oxidation resistance. Specimens with both low level and high level cold works showed a high fraction of special grain boundaries, and were tested for supercritical water oxidation resistance at 500 °C and 24 MPa. Both GBE and as-received samples exhibited mass gain followed by mass loss during 10 weeks of exposure, but the normalized mass change was small and less than 0.12 mg/cm2. GBE samples showed better oxide layer retention compared to the as-received sample. XRD results indicate that nickel oxide, chromium oxide, and spinel oxide were the three main types of oxides that form on as-received and GBE alloy 690. Three distinct regions were identified on the oxidized surface: a flat region with oxide flakes aligning relatively parallel to the surface, a rough region with polygon-type oxide particles randomly distributed on the surface, and a region with aggregated oxide flakes perpendicular to the surface. The flat region of oxidation consisted of (1 1 1) orientated oxide spinel flakes formed on (1 1 1) oriented alloy 690 grains. The flat oxide region was thinner and showed better oxide adhesion compared to the rough region. Chromium oxidation was found only at random grain boundaries, leading to formation of thick Cr2O3 layer on the surface and chromium depletion underneath. None of this oxidation was found at low angle or special boundaries. The chromium oxidation was attributed to fast chromium diffusion through random boundaries and mechanically deformed regions such as scratches left after polishing. It is envisioned that the oxidation behavior of alloy 690 in supercritical water can be tailored by microstructure

  9. Motives in Sexual Aggression: The Chinese Context.

    ERIC Educational Resources Information Center

    Tang, Catherine So-Kum; And Others

    1993-01-01

    Compared sexual and aggressive motives for sexual aggression in Chinese college students. Male undergraduates (N=146) completed self-report measures. Results suggest that sex guilt and aggressive guilt acted as inhibitors for their respective drives and sexual aggression resulted from aggressive, rather than sexual, motives. Sexual aggression may…

  10. Hydroxyl radical measurements and oxidation capacity in a boreal forest environment

    NASA Astrophysics Data System (ADS)

    Hens, K.; Tatum Ernest, C.; Novelli, A.; Paasonen, P.; Sipilä, M.; Petäjä, T.; Nölscher, A.; Taraborrelli, D.; Keronen, P.; Trawny, K.; Kubistin, D.; Oswald, R.; Axinte, R.; Hosaynali Beygi, Z.; Auld, J.; Klüpfel, T.; Mesarchaki, E.; Song, W.; Valverde Canossa, J.; González Orozco, D.; Königstedt, R.; Bohn, B.; Rudolf, M.; Fischer, H.; Williams, J.; Crowley, J.; Martinez, M.; Harder, H. D.; Lelieveld, J.

    2012-12-01

    Forests cover about one third of the earth's total land surface and are known to be an important global source of biogenic volatile organic compounds (BVOCs) that are partly very reactive towards OH. Different types of forests are known to emit various characteristic BVOCs significantly influencing atmospheric oxidation chemistry. Measurements of OH and HO2 radicals in forest environments, however, reveal a serious lack of understanding of the underlying processes. The HUMPPA-COPEC intensive field campaign took place in summer 2010 at the SMEAR II station, located in Hyytiälä, Southern Finland, as collaboration between the Max Planck Institute for Chemistry and the University of Helsinki. The main goal of the campaign was to investigate the summertime emissions and photochemistry in a boreal forest. Comprehensive measurements including observations of many VOCs, HOx, and total OH reactivity were conducted to increase our understanding of atmospheric self-cleaning processes based on detailed analysis of production and loss mechanisms of the hydroxyl radical. Also the HOx budget in a coniferous forest was examined by using direct calculations from measured species as well as an observationally constrained chemical box model in steady state. For HUMPPA-COPEC chemical reaction schemes considering isoprene as the predominant primary BVOC lead to an over prediction of the measured OH concentration by a factor of up to 4. However, only a minor fraction of the measured total OH reactivity can be explained by measured isoprene. A preliminary terpene mechanism, taking the most abundant terpenes measured during HUMPPA-COPEC-2010 and their oxidation products into account, improves the agreement between simulated and measured OH, but is not sufficient to explain the missing OH reactivity in all cases. HO2 is described reasonably well by the model for conditions where the modeled and measured total OH reactivity agree. For lower than measured reactivity, the HO2 mixing ratios

  11. Contrasts in spatial and temporal variability of oxidative capacity and elemental composition in moxibustion, indoor and outdoor environments in Beijing.

    PubMed

    Huang, Jian; Lim, Min Yee; Hwang, Chaxi; Zhao, Baixiao; Shao, Longyi

    2015-07-01

    Moxibustion is a traditional Chinese medicine therapy that burns moxa floss which produces a substantial amount of PM10 into the environment, thus spawning safety concerns about health impacts of the smoke. We compared the oxidative capacity and elemental composition of moxibustion-derived and ambient PM10 in summer and winter to provide a source-, spatial- and temporal-comparison of PM10 biological responses. The PM10 oxidative capacity was 2.04 and 1.45 fold lower, and dose-dependent slope gradient was 2.36 and 1.76 fold lower in moxibustion environment than indoor or outdoor. Oxidative damage was highly correlated with iron, cesium, aluminum and cobalt in indoor, but moxibustion environment displayed low associations. The total elemental concentration was also lower in moxibustion environment than indoor (2.28 fold) or outdoor (2.79 fold). The source-to-dose modeling and slope gradient analysis in this study can be used as a model for future source-, spatial- and temporal-related moxibustion safety evaluation studies. PMID:25818086

  12. Evaluating Primers for Profiling Anaerobic Ammonia Oxidizing Bacteria within Freshwater Environments

    PubMed Central

    Sonthiphand, Puntipar; Neufeld, Josh D.

    2013-01-01

    Anaerobic ammonia oxidizing (anammox) bacteria play an important role in transforming ammonium to nitrogen gas and contribute to fixed nitrogen losses in freshwater environments. Understanding the diversity and abundance of anammox bacteria requires reliable molecular tools, and these are not yet well established for these important Planctomycetes. To help validate PCR primers for the detection of anammox bacteria within freshwater ecosystems, we analyzed representative positive controls and selected samples from Grand River and groundwater sites, both from Ontario, Canada. The objectives of this study were to identify a suitable anammox denaturing gradient gel electrophoresis (DGGE) fingerprint method by using GC-clamp modifications to existing primers, and to verify the specificity of anammox-specific primers used for DGGE, cloning and qPCR methods. Six primer combinations were tested from four published primer sets (i.e. A438f/A684r, Amx368f/Amx820r, An7f/An1388r, and Pla46/1392r) for both direct and nested PCR amplifications. All PCR products were run subsequently on DGGE gels to compare the resulting patterns. Two anammox-specific primer combinations were also used to generate clone libraries and quantify anammox bacterial 16S rRNA genes with qPCR. The primer set A438f/A684r was highly specific to anammox bacteria, provided reliable DGGE fingerprints and generated a high proportion of anammox-related clones. A second primer set (Amx368f/Amx820r) was anammox specific, based on clone library analysis, but PCR products from different candidate species of anammox bacteria resolved poorly using DGGE analysis. Both DGGE and cloning results revealed that Ca. Brocadia and an uncharacterized anammox bacterial cluster represented the majority of anammox bacteria found in Grand River sediment and groundwater samples, respectively. Together, our results demonstrate that although Amx368f/Amx820r was useful for anammox-specific qPCR and clone library analysis, A438f/A684r

  13. High temperature oxidation behaviour of nanostructured cermet coatings in a mixed CO2 - O2 environment

    NASA Astrophysics Data System (ADS)

    Farrokhzad, M. A.; Khan, T. I.

    2014-06-01

    Nanostructured ceramic-metallic (cermet) coatings composed of nanosized ceramic particles (α-Al2O3 and TiO2) dispersed in a nickel matrix were co-electrodeposited and then oxidized at 500°C, 600°C and 700°C in a mixed gas using a Thermo-gravimetric Analysis (TGA) apparatus. The mixed gas was composed of 15% CO2, 10% O2 and 75% N2. This research investigates the effects of CO2 and O2 partial pressures on time-depended oxidation rates for coatings and compared them to the results from atmospheric oxidation under similar temperatures. The increase in partial pressure of oxygen due to the presence of CO2 at each tested temperature was calculated and correlated to the oxidation rate of the coatings. The results showed that the presence of CO2 in the system increased the oxidation rate of cermet coatings when compared to atmospheric oxidation at the same temperature. It was also shown that the increase in the oxidation rate is not the result of CO2 acting as the primary oxidant but as a secondary oxidant which results in an increase of the total partial pressure of oxygen and consequently higher oxidation rates. The WDS and XRD analyses results showed that the presence of nanosized TiO2 particles in a nickel matrix can improve oxidation behaviour of the coatings by formation of Ni-Ti compounds on oxidizing surface of the coating which was found beneficiary in reducing the oxidation rates for cermet coatings.

  14. Aggression as positive reinforcement in people with intellectual disabilities.

    PubMed

    May, Michael E

    2011-01-01

    From an applied behavior-analytic perspective, aggression in people with intellectual disabilities is mostly maintained by social reinforcement consequences. However, nonsocial consequences have also been identified in functional assessments on aggression. Behaviors producing their own reinforcement have been labeled "automatic" or "nonsocial" in the behavior-analytic literature, a label that bares a striking resemblance to biobehavioral explanations of reward-seeking behaviors. Biobehavioral studies have revealed that aggression activates the same endogenous brain mechanisms as primary reinforcers like food. Therefore, integrating brain-environment explanations would result in a better understanding of the functional mechanisms associated with nonsocial aggression. The purpose of this paper was to explore aggression as a reinforcing consequence for reinforcement-seeking behaviors in people with intellectual disabilities. First, the literature establishing aggression as reinforcement for arbitrary responding will be reviewed. Next, the reward-related biological process associated with aggression was described. Finally, the paper discusses what might be done to assess and treat aggression maintained by nonsocial reinforcement. PMID:21700420

  15. Oxidation of diclofenac with chlorine dioxide in aquatic environments: influences of different nitrogenous species.

    PubMed

    Wang, Yingling; Liu, Haijin; Liu, Guoguang; Xie, Youhai; Ni, Tianjun

    2015-06-01

    The oxidation of diclofenac (DCF), a non-steroidal anti-inflammatory drug and emerging water pollutant, with chlorine dioxide was investigated under simulated water disinfection conditions. The reaction kinetics as functions of the initial concentrations of DCF, different nitrogenous species, and different pE values were experimentally determined. The results demonstrated that DCF reacted rapidly with ClO2, where more than 75 % of DCF (≤3.00 μM) was removed by 18.94 μM ClO2 within 60 s. All of the reactions followed pseudo first-order kinetics with respect to DCF, and the rate constant, k obs, exhibited a significant decrease from 4.21 × 10(-2) to 8.09 × 10(-3) s(-1), as the initial DCF concentration was increased from 1.00 to 5.00 μM. Furthermore, the degradation kinetics of DCF was clearly dependent on nitrogen-containing ion concentrations in the reaction solution. Ammonium and nitrite ions inhibited the DCF degradation by ClO2, whereas nitrate ion clearly initiated its promotion. In contrast, the inhibitory effect of NO2 (-) was more robust than that of NH4 (+). When the values of pE were gradually increased, the transformation of NH4 (+) to NO2 (-), and subsequently to NO3 (-), would occur, the rate constants were initially decreased, and then increased. When NH4 (+) and NO2 (-) coexisted, the inhibitory effect on the DCF degradation was less than the sum of the partial inhibitory effect. However, when NO2 (-) and NO3 (-) coexisted, the actual inhibition rate was greater than the theoretical estimate. These results indicated that the interaction of NH4 (+) and NO2 (-) was antagonistic, while the coexistence of NO2 (-) and NO3 (-) was observed to have a synergistic effect in aqueous environments. PMID:25604564

  16. Solubility Behavior and Phase Stability of Transition Metal Oxides in Alkaline Hydrothermal Environments

    SciTech Connect

    S.E. Ziemniak

    2000-05-18

    The solubility behavior of transition metal oxides in high temperature water is interpreted by recognizing three types of chemical reaction equilibria: metal oxide hydration/dehydration, metal oxide dissolution and metal ion hydroxocomplex formation. The equilibria are quantified using thermodynamic concepts and the thermochemical properties of the metal oxides/ions representative of the most common constituents of construction metal alloys, i.e., element shaving atomic numbers between Z = 22 (Ti) and Z = 30 (Zn), are summarized on the basis of metal oxide solubility studies conducted in the laboratory. Particular attention is devoted to the uncharged metal ion hydrocomplex, M{sup Z}(OH){sub Z}(aq), since its thermochemical properties define minimum solubilities of the metal oxide at a given temperature. Experimentally-extracted values of standard partial molal entropy (S{sup 0}) for the transition metal ion neutral hydroxocomplex are shown to be influenced by ligand field stabilization energies and complex symmetry.

  17. Human Aggression Across the Lifespan: Genetic Propensities and Environmental Moderators

    PubMed Central

    Tuvblad, Catherine; Baker, Laura A.

    2013-01-01

    This chapter reviews the recent evidence of genetic and environmental influences on human aggression. Findings from a large selection of the twin and adoption studies that have investigated the genetic and environmental architecture of aggressive behavior are summarized. These studies together show that about half (50%) of the variance in aggressive behavior is explained by genetic influences in both males and females, with the remaining 50% of the variance being explained by environmental factors not shared by family members. Form of aggression (reactive, proactive, direct/physical, indirect/relational), method of assessment (laboratory observation, self-report, ratings by parents and teachers), and age of the subjects—all seem to be significant moderators of the magnitude of genetic and environmental influences on aggressive behavior. Neither study design (twin vs. sibling adoption design) nor sex (male vs. female) seems to impact the magnitude of the genetic and environmental influences on aggression. There is also some evidence of gene-environment interaction (G × E) from both twin/adoption studies and molecular genetic studies. Various measures of family adversity and social disadvantage have been found to moderate genetic influences on aggressive behavior. Findings from these G × E studies suggest that not all individuals will be affected to the same degree by experiences and exposures, and that genetic predispositions may have different effects depending on the environment. PMID:22078481

  18. Environment.

    ERIC Educational Resources Information Center

    White, Gilbert F.

    1980-01-01

    Presented are perspectives on the emergence of environmental problems. Six major trends in scientific thinking are identified including: holistic approaches to examining environments, life support systems, resource management, risk assessment, streamlined methods for monitoring environmental change, and emphasis on the global framework. (Author/SA)

  19. Feline aggression toward family members: a guide for practitioners.

    PubMed

    Bain, Melissa; Stelow, Elizabeth

    2014-05-01

    Feline aggression toward people is a common and potentially dangerous problem. Proper diagnosis of the underlying cause of the aggression is key in effective treatment. A complete history, including information on the people in the home, other pets, and specific incidents, is necessary to make this diagnosis. A comprehensive treatment plan typically includes management, enhancement of the cat's living environment, techniques for replacing the aggressive behavior with more appropriate behaviors, and, potentially, medication. The treatment plan must reflect the abilities and commitment of the owner. PMID:24766701

  20. The nature of human aggression.

    PubMed

    Archer, John

    2009-01-01

    Human aggression is viewed from four explanatory perspectives, derived from the ethological tradition. The first consists of its adaptive value, which can be seen throughout the animal kingdom, involving resource competition and protection of the self and offspring, which has been viewed from a cost-benefit perspective. The second concerns the phylogenetic origin of aggression, which in humans involves brain mechanisms that are associated with anger and inhibition, the emotional expression of anger, and how aggressive actions are manifest. The third concerns the origin of aggression in development and its subsequent modification through experience. An evolutionary approach to development yields conclusions that are contrary to the influential social learning perspective, notably that physical aggression occurs early in life, and its subsequent development is characterized by learned inhibition. The fourth explanation concerns the motivational mechanisms controlling aggression: approached from an evolutionary background, these mechanisms range from the inflexible reflex-like responses to those incorporating rational decision-making. PMID:19411108

  1. Girls, aggression, and emotion regulation.

    PubMed

    Conway, Anne M

    2005-04-01

    Many studies have demonstrated that boys are more aggressive than girls (see J. D. Coie & K. Dodge, 1997, for a review) and that emotion regulation difficulties are associated with problematic behaviors (N. Eisenberg & R. A. Fabes, 1999; M. Gilliom, D. S. Shaw, J. E. Beck, M. A. Schonberg, & J. L. Lukon, 2002). However, recent findings indicate that gender differences in aggressive behaviors disappear when assessments are broadened to include relational aggression--behaviors designed to harm the relationship goals of others by spreading rumors, gossiping, and eliciting peer rejection of others. Moreover, although difficulties regulating emotions have been reported for physically aggressive children, little research has examined these processes in relationally aggressive children. This article argues that investigation into the associations between emotion regulation and relational aggression is a critical direction for future research on the etiology and prevention of mental health problems in girls. PMID:15839769

  2. Oxidative DNA damage levels and catalase activity in the clam Ruditapes decussatus as pollution biomarkers of Tunisian marine environment.

    PubMed

    Jebali, Jamel; Banni, Mohamed; de Almeida, Eduardo Alves; Boussetta, Hamadi

    2007-01-01

    Levels of the oxidative DNA damage 7, 8-dihydro-8-oxo-2'-deoxyguanosine (8-oxodG) and catalase (CAT) activity were measured in the digestive gland and gills of clams Ruditapes decussatus, related to the presence of pollutants along Tunisian marine environment. Increased levels of CAT were observed in tissues of clams from all the sites studied, compared to control values, and elevated 8-oxodG levels were observed at specific sites. Results obtained in this work indicate that the measurement of 8-oxodG levels and CAT activity in tissues of R. decussatus is promising in pollution monitoring studies of the Tunisian marine environment. PMID:16897518

  3. An efficient and environment-friendly method of removing graphene oxide in wastewater and its degradation mechanisms.

    PubMed

    Zhang, Chao-Zhi; Li, Ting; Yuan, Yang; Xu, Jianqiang

    2016-06-01

    Graphene and graphene oxide (GO) have already existed in air, water and soil due to their popular application in functional materials. However, degradation of graphene and GO in wastewater has not been reported. Degradation of GO plays a key role in the elimination of graphene and GO in wastewater due to graphene being easily oxidized to GO. In this paper, GO was completely degraded to give CO2 by Photo-Fenton. The degradation intermediates were determined by UV-vis absorption spectra, elemental analysis (EA), fourier transform infrared (FT-IR) and liquid chromatography-mass spectrometry (LC-MS). Experimental results showed that graphene oxide was completely degraded to give CO2 after 28 days. Based on UV, FT-IR, LC-MS spectra and EA data of these degradation intermediates, the degradation mechanisms of GO were supposed. This paper suggests an efficient and environment-friendly method to degrade GO and graphene. PMID:27042978

  4. 6th COSTAM/SFRR (ASEAN/Malaysia) International Workshop on Micronutrients, Oxidative Stress, and the Environment.

    PubMed

    Nesaretnam, Kalanithi; Sies, Helmut

    2006-01-01

    The 6(th) COSTAM/SFRR (ASEAN/Malaysia) workshop, "Micronutrients, Oxidative Stress, and the Environment," was held from June 29 to July 2 at Holiday Inn Damai Beach Resort in Kuching, Sarawak. Two hundred twenty participants from 17 countries presented recent advances on natural antioxidants in the area of oxidative stress and molecular aspects of nutrition. Natural products and research are an important program in academic institutions and are experiencing unprecedented interest and growth by the scientific community and public health authorities. Progress is being driven by better understanding of the molecular mechanisms of the relation between oxidative stress and micronutrient action. The gathering of scientists from around the world was fruitful, and we hope that future work will be developed by the formal and informal interactions that took place in this beautiful tropical setting. PMID:17034360

  5. The behavior of SiC and Si3N4 ceramics in mixed oxidation/chlorination environments

    NASA Technical Reports Server (NTRS)

    Marra, John E.; Kreidler, Eric R.; Jacobson, Nathan S.; Fox, Dennis S.

    1989-01-01

    The behavior of silicon-based ceramics in mixed oxidation/chlorination environments was studied. High pressure mass spectrometry was used to quantitatively identify the reaction products. The quantitative identification of the corrosion products was coupled with thermogravimetric analysis and thermodynamic equilibrium calculations run under similar conditions in order to deduce the mechanism of corrosion. Variations in the behavior of the different silicon-based materials are discussed. Direct evidence of the existence of silicon oxychloride compounds is presented.

  6. Very high-cycle fatigue failure in micron-scale polycrystalline silicon films: Effects of environment and surface oxide thickness

    NASA Astrophysics Data System (ADS)

    Alsem, D. H.; Timmerman, R.; Boyce, B. L.; Stach, E. A.; De Hosson, J. Th. M.; Ritchie, R. O.

    2007-01-01

    Fatigue failure in micron-scale polycrystalline silicon structural films, a phenomenon that is not observed in bulk silicon, can severely impact the durability and reliability of microelectromechanical system devices. Despite several studies on the very high-cycle fatigue behavior of these films (up to 1012cycles), there is still an on-going debate on the precise mechanisms involved. We show here that for devices fabricated in the multiuser microelectromechanical system process (MUMPs) foundry and Sandia Ultra-planar, Multi-level MEMS Technology (SUMMiT V™) process and tested under equi-tension/compression loading at ˜40kHz in different environments, stress-lifetime data exhibit similar trends in fatigue behavior in ambient room air, shorter lifetimes in higher relative humidity environments, and no fatigue failure at all in high vacuum. The transmission electron microscopy of the surface oxides in the test samples shows a four- to sixfold thickening of the surface oxide at stress concentrations after fatigue failure, but no thickening after overload fracture in air or after fatigue cycling in vacuo. We find that such oxide thickening and premature fatigue failure (in air) occur in devices with initial oxide thicknesses of ˜4nm (SUMMiT V™) as well as in devices with much thicker initial oxides ˜20nm (MUMPs). Such results are interpreted and explained by a reaction-layer fatigue mechanism. Specifically, moisture-assisted subcritical cracking within a cyclic stress-assisted thickened oxide layer occurs until the crack reaches a critical size to cause catastrophic failure of the entire device. The entirety of the evidence presented here strongly indicates that the reaction-layer fatigue mechanism is the governing mechanism for fatigue failure in micron-scale polycrystalline silicon thin films.

  7. Interactions of the metal tolerant heterotrophic microorganisms and iron oxidizing autotrophic bacteria from sulphidic mine environment during bioleaching experiments.

    PubMed

    Jeremic, Sanja; Beškoski, Vladimir P; Djokic, Lidija; Vasiljevic, Branka; Vrvić, Miroslav M; Avdalović, Jelena; Gojgić Cvijović, Gordana; Beškoski, Latinka Slavković; Nikodinovic-Runic, Jasmina

    2016-05-01

    Iron and sulfur oxidizing chemolithoautotrophic acidophilic bacteria, such as Acidithiobacillus species, hold the dominant role in mine environments characterized by low pH values and high concentrations of reduced sulfur and iron compounds, such as ores, rocks and acid drainage waters from mines. On the other hand, heterotrophic microorganisms, especially their biofilms, from these specific niches are receiving increased attention, but their potential eco-physiological roles have not been fully understood. Biofilms are considered a threat to human health, but biofilms also have beneficial properties as they are deployed in waste recycling and bioremediation systems. We have analyzed interactions of the metal tolerant heterotrophic microorganisms in biofilms with iron oxidizing autotrophic bacteria both from the sulphidic mine environment (copper mine Bor, Serbia). High tolerance to Cu(2+), Cd(2+) and Cr(6+) and the presence of genetic determinants for the respective metal tolerance and biofilm-forming ability was shown for indigenous heterotrophic bacteria that included strains of Staphylococcus and Rhodococcus. Two well characterized bacteria- Pseudomonas aeruginosa PAO1 (known biofilm former) and Cupriavidus metallidurans CH34 (known metal resistant representative) were also included in the study. The interaction and survivability of autotrophic iron oxidizing Acidithiobacillus bacteria and biofilms of heterotrophic bacteria during co-cultivation was revealed. Finally, the effect of heterotrophic biofilms on bioleaching process with indigenous iron oxidizing Acidithiobacillus species was shown not to be inhibitory under in vitro conditions. PMID:26942859

  8. Quantitative Analysis of Major Phytochemicals in Orthodox tea (Camellia sinensis), Oxidized under Compressed Air Environment.

    PubMed

    Panda, Brajesh Kumar; Datta, Ashis Kumar

    2016-04-01

    This study describes major changes in phytochemical composition of orthodox tea (Camellia sinensis var. Assamica) oxidized under compressed air (CA). The experiments for oxidation were conducted under air pressure (101, 202, and 303 kPa) for 150 min. Relative change in the concentrations of caffeine, catechins, theaflavins (TF), and thearubigins (TR) were analyzed. Effect of CA pressure was found to be nonsignificant in regulating caffeine concentration during oxidation. But degradation in different catechins as well as formation of different TF was significantly affected by CA pressure. At high CA pressure, TF showed highest peak value. TR was found to have slower rate of formation during initial phase of oxidation than TF. Even though the rate of TR formation was significantly influenced by CA, a portion of catechins remained unoxidized at end of oxidation. Except caffeine, the percent change in rate of formation or degradation were more prominent at 202 kPa. PMID:26970442

  9. Nitrones are able to release nitric oxide in aqueous environment under hydroxyl free radical attack.

    PubMed

    Croitoru, Mircea Dumitru; Ibolya, Fülöp; Pop, Maria Cristiana; Dergez, Timea; Mitroi, Brânduşa; Dogaru, Maria Titica; Tokés, Béla

    2011-10-30

    Importance of a nitric oxide donor that can act as a spin trap might bring some new therapeutic possibilities regarding the treatment of ischemic diseases by reducing the intensity of free radical produced reperfusion lesions. These substances might be also used as a new type of photo protectors since they can absorb UV radiation, capture free radicals formed by interaction of UV radiation with tissue constituents, and tanning of the skin will be permitted due to nitric oxide release. The purpose of this work was to measure the ability of nitrones to release nitric oxide and how different factors (temperature, nitrone concentration, and free radicals) influence the releasing ability. Mostly, indirect determination of nitric oxide was carried out, by measuring nitrite and nitrate amounts (as decomposition products of nitric oxide), all nitrones proved to release significant amounts of nitric oxide. Nitrite measurements were made based on an HPLC-VIS method that uses pre-column derivatization of nitrite by forming an azo dye (limit of quantification: 5ng/ml). No good correlation was found between the amount of nitric oxide and temperature for most studied nitrones but between the formation of nitric oxide and nitrone concentration an asymptotic correlation was found. Fenton reagent also yielded formation of nitric oxide from nitrones and formed amounts were not different from those recorded for UV irradiation. Most of the nitrones effectively released about 0.5% of the maximum amount of nitric oxide that is chemically possible and estimated concentrations of 0.1μM were present in the solutions during decomposition. PMID:21645628

  10. Rethinking Aggression: A Typological Examination of the Functions of Aggression.

    ERIC Educational Resources Information Center

    Little, Todd D.; Brauner, Jessica; Jones, Stephanie M.; Nock, Matthew K.; Hawley, Patricia H.

    2003-01-01

    Compared five subgroups of aggressive children and adolescents on several adjustment correlates. Found that the reactive group and the group high on both instrumental and reactive reasons for aggression showed consistent maladaptive patterns across the adjustment correlates. The instrumental and typical groups (moderate on instrumental and…

  11. Evolution of a Higher Intracellular Oxidizing Environment in Caenorhabditis elegans under Relaxed Selection

    PubMed Central

    Cousins, Dustin; Keller, Michelle; Denver, Dee R.; Baer, Charles F.; Estes, Suzanne

    2013-01-01

    We explored the relationship between relaxed selection, oxidative stress, and spontaneous mutation in a set of mutation-accumulation (MA) lines of the nematode Caenorhabditis elegans and in their common ancestor. We measured steady-state levels of free radicals and oxidatively damaged guanosine nucleosides in the somatic tissues of five MA lines for which nuclear genome base substitution and GC-TA transversion frequencies are known. The two markers of oxidative stress are highly correlated and are elevated in the MA lines relative to the ancestor; point estimates of the per-generation rate of mutational decay (ΔM) of these measures of oxidative stress are similar to those reported for fitness-related traits. Conversely, there is no significant relationship between either marker of oxidative stress and the per-generation frequencies of base substitution or GC-TA transversion. Although these results provide no direct evidence for a causative relationship between oxidative damage and base substitution mutations, to the extent that oxidative damage may be weakly mutagenic in the germline, the case for condition-dependent mutation is advanced. PMID:23776511

  12. Plasma selenium levels and oxidative stress biomarkers: a gene-environment interaction population-based study.

    PubMed

    Galan-Chilet, Inmaculada; Tellez-Plaza, Maria; Guallar, Eliseo; De Marco, Griselda; Lopez-Izquierdo, Raul; Gonzalez-Manzano, Isabel; Carmen Tormos, M; Martin-Nuñez, Gracia M; Rojo-Martinez, Gemma; Saez, Guillermo T; Martín-Escudero, Juan C; Redon, Josep; Javier Chaves, F

    2014-09-01

    The role of selenium exposure in preventing chronic disease is controversial, especially in selenium-repleted populations. At high concentrations, selenium exposure may increase oxidative stress. Studies evaluating the interaction of genetic variation in genes involved in oxidative stress pathways and selenium are scarce. We evaluated the cross-sectional association of plasma selenium concentrations with oxidative stress levels, measured as oxidized to reduced glutathione ratio (GSSG/GSH), malondialdehyde (MDA), and 8-oxo-7,8-dihydroguanine (8-oxo-dG) in urine, and the interacting role of genetic variation in oxidative stress candidate genes, in a representative sample of 1445 men and women aged 18-85 years from Spain. The geometric mean of plasma selenium levels in the study sample was 84.76 µg/L. In fully adjusted models the geometric mean ratios for oxidative stress biomarker levels comparing the highest to the lowest quintiles of plasma selenium levels were 0.61 (0.50-0.76) for GSSG/GSH, 0.89 (0.79-1.00) for MDA, and 1.06 (0.96-1.18) for 8-oxo-dG. We observed nonlinear dose-responses of selenium exposure and oxidative stress biomarkers, with plasma selenium concentrations above ~110 μg/L being positively associated with 8-oxo-dG, but inversely associated with GSSG/GSH and MDA. In addition, we identified potential risk genotypes associated with increased levels of oxidative stress markers with high selenium levels. Our findings support that high selenium levels increase oxidative stress in some biological processes. More studies are needed to disentangle the complexity of selenium biology and the relevance of potential gene-selenium interactions in relation to health outcomes in human populations. PMID:25017966

  13. Corrosion behavior of an HVOF-sprayed Fe3Al coating in a high-temperature oxidizing/sulfidizing environment

    SciTech Connect

    Covino, Bernard S., Jr.; Bullard, Sophie J.; Cramer, Stephen D.; Holcomb, Gordon R.; Ziomek-Moroz, Margaret; Shrestha, S.; Harvey, D.

    2005-01-01

    An iron aluminide (Fe3Al) intermetallic coating was deposited onto a F22 (2.25Cr-1Mo) steel substrate using a JP-5000 high velocity oxy-fuel (HVOF) thermal spray system. The as-sprayed coating was examined by electron microscopy and X-ray diffraction and was characterized in terms of oxidation and adhesion. Fe3Al-coated steel specimens were exposed to a mixed oxidizing/sulfidizing environment at 500, 600, 700, and 800DGC for approximately seven days. The gaseous environment consisted of N2-10%CO-5%CO2-2%H2O-0.12%H2S (by volume). All specimens gained mass after exposure to the environment and the mass gains were found to be inversely proportional to temperature increases. Representative specimens exposed at each temperature were cross-sectioned and subjected to examination under a scanning electron microscope (SEM) and X-ray mapping. Results are presented in terms of corrosion weight gain and corrosion product formation. The purpose of the research presented here was to evaluate the effectiveness of an HVOF-sprayed Fe3Al coating in protecting a steel substrate exposed to a fossil energy environment.

  14. Aggression, suicidality, and serotonin.

    PubMed

    Linnoila, V M; Virkkunen, M

    1992-10-01

    Studies from several countries, representing diverse cultures, have reported an association between violent suicide attempts by patients with unipolar depression and personality disorders and low concentrations of the major serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the cerebrospinal fluid (CSF). Related investigations have documented a similar inverse correlation between impulsive, externally directed aggressive behavior and CSF 5-HIAA in a subgroup of violent offenders. In these individuals, low CSF 5-HIAA concentrations are also associated with a predisposition to mild hypoglycemia, a history of early-onset alcohol and substance abuse, a family history of type II alcoholism, and disturbances in diurnal activity rhythm. These data are discussed in the context of a proposed model for the pathophysiology of a postulated "low serotonin syndrome." PMID:1385390

  15. The Effects of Pornography on Aggressive Behavior.

    ERIC Educational Resources Information Center

    Stacy, Lauri L.

    This document reviews existing empirical research on the effect of pornography on aggressive behavior. Two types of pornography are distinguished: aggressive pornography and non-aggressive pornography. Conclusions drawn from the research review are presented, including: (1) aggressive pornograpy consistently increases aggressive attitudes and…

  16. Subtypes of Aggressive Behaviors: A Developmental Perspective

    ERIC Educational Resources Information Center

    Vitaro, Frank; Brendgen, Mara; Barker, Edward D.

    2006-01-01

    Aggressive behaviors in children and adolescents have undergone important conceptual and definitional modifications in the past two decades. In particular, subtypes of aggression have been proposed that separate the form and the function of the aggressive behaviors (i.e., social vs. physical aggression; reactive vs. proactive aggression).…

  17. The impact of match-play tennis in a hot environment on indirect markers of oxidative stress and antioxidant status

    PubMed Central

    Knez, Wade L; Périard, JP

    2014-01-01

    Objectives The purpose of this study was to determine the impact of changes in oxidative stress and antioxidant status in response to playing tennis in HOT (∼36°C and 35% relative humidity (RH)) and COOL (∼22°C and 70% RH) conditions. Methods 10 male tennis players undertook two matches for an effective playing time (ie, ball in play) of 20 min, corresponding to ∼122 and ∼107 min of total play in HOT and COOL conditions, respectively. Core body temperature, body mass and indirect markers of oxidative stress (diacrons reactive oxygen metabolic test) and antioxidant status (biological antioxidant potential test) were assessed immediately prematch, midmatch and postmatch, and 24 and 48 h into recovery. Results Regardless of the condition, oxidative stress remained similar throughout play and into recovery. Likewise, match-play tennis in the COOL had no impact on antioxidant status. However, antioxidants status increased significantly in the HOT compared with COOL environment (p<0.05). Body mass losses (∼0.5 kg) were similar between conditions. Rectal temperature increased during both matches (p<0.05), but with a greater magnitude in the HOT (39.3±0.5°C) versus COOL (38.7±0.2°C) environment (p<0.05). Conclusions Match-play tennis in the heat does not exacerbate the development of oxidative stress, but significantly increases antioxidant status. These data suggest that the heat stress observed in the HOT environment may provide a necessary signal for the upregulation of antioxidant defence, dampening cellular damage. PMID:24668382

  18. A computational study of the effect of the metal organic framework environment on the release of chemically stored nitric oxide.

    PubMed

    Li, Tanping; Taylor-Edinbyrd, Kiara; Kumar, Revati

    2015-09-28

    The use of copper based metal organic frameworks as a vehicle for the storage and delivery of chemically stored nitric oxide has been proposed based on recent experiments [J. Am. Chem. Soc., 2012, 134, 3330-3333]. In these experiments copper based metal organic frameworks (MOFs) suspended in ethanol catalytically convert chemically stored nitric oxide (in the S-nitrosothiol or RSNO form) to free nitric oxide at a slow and sustained rate, as compared to a quick release in a solution of ethanol containing free copper ions. In order to gain insight on the effect of the MOF environment on the catalytic activity, a combination of electronic structure calculations on representative clusters and classical simulations using a force-field (partly parameterized on the above calculations) is used to study a simple RSNO species, S-nitrosomethane (CH3SNO) as well as the biologically compatible S-nitrosocysteine, both in the MOF and free copper solution. The free energy profiles of bringing the RSNO species to the catalytic centers have been compared and related to the different solvation environments of the copper catalyst in the complex solvated MOF and in free copper solution. Surprisingly, in the case of the simple CH3SNO moiety as well as the S-nitrosocysteine case, the free energy profile of bringing the first RSNO from the center of one of the pores to the catalytic site in the pore is very similar to the free solution case. On the other hand, bringing a second RSNO molecule to the same catalytic site or to the adjacent catalytic copper site show relatively higher barriers. These studies help shed light on the sustained nitric oxide release in the MOF environment. PMID:26292051

  19. Biocompatible nanocarriers that respond to oxidative environments via interactions between chitosan and multiple metal ions

    PubMed Central

    Zhang, Shichang; Xia, Liye; Ding, Chenchen; Wen, Lu; Wan, Weihua; Chen, Gang

    2016-01-01

    Hydrogen peroxide (H2O2) functions as an early damage signal contributing to the oxidative stress response and can act as a trigger in smart oxidation-responsive drug delivery systems that are currently in development. Current H2O2-triggered oxidation-responsive polymeric systems are usually derived from chemical synthesis and rarely include natural polymers. Herein, we report two series of nanoparticle (NP) complexes prepared with the biopolymer chitosan (CS) and four different metal ions (Cu2+, Ca2+, Zn2+, and Fe3+), defined as CSNPs-metal complexes (Series 1) and CS-metal complexes NPs (Series 2), which responded to oxidation by dissolving upon H2O2 exposure. Experiments examining Nile red release and H2O2-triggered degradation confirmed that both series of complexes showed better sensitivity to oxidation than the CSNPs alone. Furthermore, preliminary cytotoxicity and histological observations indicated that the two series exhibited little or no cytotoxicity and generated a mild inflammatory response. Our work provides a novel and promising strategy for developing NPs for use as intelligent oxidation-responsive systems. PMID:27358564

  20. Aggression and Violence in Youth.

    ERIC Educational Resources Information Center

    William Gladden Foundation, York, PA.

    This booklet was written to provide an understanding of aggression and violence in youth. Its purpose is to help parents, professionals, and other concerned citizens prevent or reduce these potentially dangerous behaviors. The introduction notes that many experts agree that aggression and violence are on the rise in America. The first section of…

  1. Lunar Influences on Human Aggression.

    ERIC Educational Resources Information Center

    Russell, Gordon W.; Dua, Manjula

    1983-01-01

    Used league records of all Canadian hockey games (N=426) played during a season to test a lunar-aggression hypothesis. Despite the use of multiple measures of lunar phase and interpersonal aggression, support for lunar influence was not forthcoming. Supplemental data revealed that beliefs in lunar influence are fairly common. (JAC)

  2. A psychoanalytic study of aggression.

    PubMed

    Furst, S S

    1998-01-01

    Eleven participants carried out a study of aggression by utilizing clinical data from the analyses of patients who manifested significant problems in the management of aggression. The purpose of the study was to increase understanding of the intrapsychic factors that determine the nature and intensity of aggressive tendencies, the place they occupy in the psychic economy, their patterns of expression, and the extrapsychic factors that trigger them. The findings of the study indicate, first, that aggression is multiply determined by developmental, genetic (experiential), and dynamic variables; second, that each cluster of variables affects the nature, intensity, and expression of aggression in a fairly specific way; third, the importance of aggression in the psychic economy is proportional to the extent to which it is overdetermined. The successful analysis of aggressive individuals depends not solely on interpretation and insight, but on the relationship to the analyst as new parent who does not threaten and prohibit. The relationship to the analyst permits developmental change, particularly the ability to organize, structure, and control aggression. As a result, it need not be expressed destructively, but may be placed in the service of constructive thought and action. PMID:9990829

  3. In search of Winnicott's aggression.

    PubMed

    Posner, B M; Glickman, R W; Taylor, E C; Canfield, J; Cyr, F

    2001-01-01

    Going beyond Winnicott's widely known ideas about creativity, in this paper the authors ask why some people are able to live creatively while others suffer recurrent feelings of anger, futility, and depression. Examining Winnicott's reframing of aggression as a life force, it attempts to answer this question by tracing the evolution of his thinking on the nature and origin of aggression. It argues that because he saw aggression as inherent and as central to emotional development, interference in its expression compromises psychic maturation. The paper explores how Winnicott arrived at the conception of a combined love-strife drive and demonstrates that for him, there is no love without aggression, no subject, no object, no reality, and no creativity. That is, for Winnicott, aggression is an achievement that leads to the capacity to live creatively and to experience authenticity. Clinical vignettes illustrate the therapeutic use of these conclusions and their value for psychoanalytic theory. PMID:12102012

  4. False memories for aggressive acts.

    PubMed

    Laney, Cara; Takarangi, Melanie K T

    2013-06-01

    Can people develop false memories for committing aggressive acts? How does this process compare to developing false memories for victimhood? In the current research we used a simple false feedback procedure to implant false memories for committing aggressive acts (causing a black eye or spreading malicious gossip) or for victimhood (receiving a black eye). We then compared these false memories to other subjects' true memories for equivalent events. False aggressive memories were all too easy to implant, particularly in the minds of individuals with a proclivity towards aggression. Once implanted, the false memories were indistinguishable from true memories for the same events, on several dimensions, including emotional content. Implications for aggression-related memory more generally as well as false confessions are discussed. PMID:23639921

  5. Predicting aggressive behavior with the aggressiveness-IAT.

    PubMed

    Banse, Rainer; Messer, Mario; Fischer, Ilka

    2015-01-01

    The Implicit Association Test (IAT, Greenwald, McGhee, & Schwartz, 1998) was adapted to assess the automatically activated (implicit) self-concept of aggressiveness. In three studies the validity of the Aggressiveness-IAT (Agg-IAT) was supported by substantial correlations with self-report measures of aggressiveness. After controlling for self-report measures of aggressiveness, the Agg-IAT accounted for 9-15% of the variance of three different indicators of aggressive behavior across three studies. To further explore the nomological network around the Agg-IAT we investigated its correlations with measures of social desirability (SD). Although not fully conclusive, the results across four studies provided some support for a weak negative correlation between impression management SD and aggressive behavior as well as the Agg-IAT. This result is in line with an interpersonally oriented self-control account of impression management SD. Individuals with high SD scores seem to behave less aggressively, and to show lower Agg-IAT scores. The one-week stability of the Agg-IAT was r = .58 in Study 4. Aggr. Behav. 41:65-83 2015. © 2014 Wiley Periodicals, Inc. PMID:27539875

  6. Instrumental and Social Outcome Expectations of High-Aggressive and Low-Aggressive Boys.

    ERIC Educational Resources Information Center

    Cillessen, Antonius H. N.; Hubbard, Julie A.

    This study examined high-aggressive and low-aggressive boys' ratings of the effectiveness of aggressive and assertive strategies for solving social problems involving hypothetical peers and actual peers. Subjects were 66 third-grade boys (11 groups of 6 boys each for a total of 22 high-aggressive, 22 low-aggressive, and 22 average aggressive boys)…

  7. Aggressive Erotica and Violence against Women.

    ERIC Educational Resources Information Center

    Donnerstein, Edward

    1980-01-01

    Examines the effects of aggressive-erotic stimuli on male aggression toward females. Male subjects' deliveries of electric shocks to males or females after viewing either a neutral, erotic, or aggressive-erotic film were measured. (Author/SS)

  8. An Exploration of Relational Aggression in the Nursing Workplace

    PubMed Central

    Dellasega, Cheryl; Volpe, Rebecca L.; Edmonson, Cole; Hopkins, Margaret

    2014-01-01

    Objective This study provides a 1st look at relational aggression (RA) and the consequences among nurses. Background Interpersonal hostility, bullying, and a toxic work environment can impact patient care delivery as well as nurses’ personal health and job satisfaction. Methods The Relational Aggression Assessment Survey (RAAS), measuring aggressors, victims and bystanders, was used to measure RA in a sample of 842 nurses. Additional variables measured included a demographic profile, job satisfaction and intent to leave. Results Nurses were most likely to identify with victim behaviors, but a minority of nurses reported relying on aggressor behaviors and bystander behaviors. There was a positive correlation among aggressor, victim and bystander items, suggesting overlap in roles. Conclusions A few relationally aggressive individuals can create a toxic work environment. Interventions to address RA among nurses must be tested, as well as strategies for improving job satisfaction and promoting healthy work environments through positive relationships. PMID:24662690

  9. Environment-dependent photochromism of silver nanoparticles interfaced with metal-oxide films

    NASA Astrophysics Data System (ADS)

    Fu, Shencheng; Sun, Shiyu; Zhang, Xintong; Zhang, Cen; Zhao, Xiaoning; Liu, Yichun

    2015-12-01

    Different metal-oxide films were fabricated by radio frequency magnetron sputtering. Further, a layer of silver nanoparticles (NPs) was deposited on the surface of the substrate by physical sputtering. Photochromism of the silver/metal-oxide nanocomposite films were investigated in situ under the irradiation of a linearly-polarized green laser beam (532 nm). Silver NPs were found to be easily photo-dissolved on the n-type metal-oxide films. By changing experimental conditions, it was also verified that both oxygen and humidity accelerate the photochromism of silver NPs. The corresponding micro-mechanism on charge separation and Ag+-ions mobility was also discussed. These results provided theoretical basis for the application of silver NPs in biological, chemical and medical areas.

  10. High-temperature-oxidation-induced ordered structure in Inconel 939 superalloy exposed to oxy-combustion environments

    SciTech Connect

    Zhu, Jingxi; Wise, Adam; Nuhfer, Thomas; Holcomb, Gordon R; Jablonski, Paul D; Sridhar, Seetharaman; Laughlin, David E

    2013-04-20

    In the integrated oxy-fuel combustion and turbine power generation system, turbine alloys are exposed to high temperature and an atmosphere comprised of steam, CO2 and O2. While surface and internal oxidation of the alloy takes place, the microstructure in the subsurface region also changes due to oxidation that results in the loss of the strengthening precipitates. In an earlier study of the oxidation of Inconel 939 Ni-based superalloy exposed to oxy-fuel combustion environment for up to 1000 hours, a high-temperature-oxidation-induced phase transformation in the sub-surface region was noticed and a two-phase region formed at the expense of strengthening γ' phase. While one of the two phases was identified as the Ni-matrix (γ solid solution, face-center-cubic) phase, the other product phase remained unidentified. In this study, the crystal structure of the unknown phase and its orientation relationship with the parent Ni-matrix phase was investigated through electron diffraction and high-resolution transmission electron microscopy. It was determined that the crystal structure of the unknown phase could be modeled as a ternary derivative of the ordered η-Ni3Ti phase (D024) structure with lattice parameters of a = 0.5092 nm and c = 0.8336 nm, α = 90º, β = 90º and γ = 120º.

  11. Aggression at Age 5 as a Function of Prenatal Exposure to Cocaine, Gender, and Environmental Risk

    PubMed Central

    Bendersky, Margaret; Bennett, David; Lewis, Michael

    2006-01-01

    Objective To examine childhood aggression at age 5 in a multiple risk model that includes cocaine exposure, environmental risk, and gender as predictors. Methods Aggression was assessed in 206 children by using multiple methods including teacher report, parent report, child’s response to hypothetical provocations, and child’s observed behavior. Also examined was a composite score that reflected high aggression across contexts. Results Multiple regression analyses indicated that a significant amount of variance in each of the aggression measures and the composite was explained by the predictors. The variables that were independently related differed depending on the outcome. Cocaine exposure, gender, and environmental risk were all related to the composite aggression score. Conclusions Cocaine exposure, being male, and a high-risk environment were all predictive of aggressive behavior at 5 years. It is this group of exposed boys at high environmental risk that is most likely to show continued aggression over time. PMID:15827351

  12. Prevalence of aggressive behaviours among inpatients with psychiatric disorders: A case study analysis from Jordan.

    PubMed

    Al-Sagarat, Ahmad Y; Hamdan-Mansour, Ayman M; Al-Sarayreh, Faris; Nawafleh, Hani; Moxham, Lorna

    2016-06-01

    In this study, we investigated the correlates of aggression among consumers with mental illness within two psychiatric hospitals in Jordan. This was a descriptive, cross sectional study carried out by auditing consumers' medical records in regards to incidents of aggression before and during admission. Approval was gained from 203 next of kins to review the consumers' medical records. Results from this case analysis, found the prevalence of aggressive behaviours among psychiatric inpatient's in Jordan to be 23.6%, the most common form of aggression was consumer to consumer and that the aggressive act was more likely to be perpetrated by younger consumers. Such findings contribute to the discourse about aggression and understanding who and what causes aggression can go toward identify strategies for early intervention and management. After all, mental health units should be places of safety, that is, an asylum, and everyone who enters that environment deserves to be safe. PMID:26538486

  13. The joint effects on Photobacterium phosphoreum of metal oxide nanoparticles and their most likely coexisting chemicals in the environment.

    PubMed

    Wang, Dali; Gao, Ya; Lin, Zhifen; Yao, Zhifeng; Zhang, Weixian

    2014-09-01

    Metal oxide nanoparticles (NPs) have been used increasingly and are likely to accumulate in natural water bodies, where they encounter and interact with other environmental chemicals. These interactions result in joint effects on biological systems and the environment. However, compared with the intensive research examining the toxicities of individual NPs, the toxicities of NP mixtures remain relatively unexplored. In this work, we studied the joint effects of NPs and their most likely coexisting chemicals in the environment, including NPs with different compositions, humic substances, and surfactants. Our results indicate that the joint effects of NP mixtures were usually simple addition, which is commonly adopted in real risk assessment. However, the joint effects obtained for mixtures that contained ZnO were exclusively associated with antagonism. In addition, the mixtures of NPs and surfactants resulted in complex joint effects, i.e., antagonistic, additive, and synergistic effects were found for the mixtures with ZnO, NiO, and Fe-oxide, respectively. Our study suggests that the assessments of the ecological risk of NPs, particularly ZnO NPs, should consider the impact of their coexisting chemicals in the environment. PMID:24911590

  14. Joint strength of a solid oxide fuel cell glass-ceramic sealant with metallic interconnect in a reducing environment

    NASA Astrophysics Data System (ADS)

    Lin, Chih-Kuang; Liu, Yu-An; Wu, Si-Han; Liu, Chien-Kuo; Lee, Ruey-Yi

    2015-04-01

    Effects of reducing environment and thermal aging on the joint strength of a BaO-B2O3-Al2O3-SiO2 glass-ceramic sealant (GC-9) with a ferritic-stainless-steel interconnect (Crofer 22 H) for planar solid oxide fuel cells are investigated. A technique is developed for conducting mechanical tests at room temperature and 800 °C in H2-7 vol% H2O under shear and tensile loadings. Given an aged condition and loading mode, the joint strength at 800 °C is lower than that at room temperature in the given humidified hydrogen atmosphere. A thermal aging at 800 °C in H2-7 vol% H2O for 100 h or 1000 h enhances both shear and tensile joint strengths at room temperature but degrades them at 800 °C in the same reducing environment. Non-aged specimens show a comparable joint strength and fracture mode when tested in humidified hydrogen and in air under a given loading mode and testing temperature. The shear strength at 800 °C for joint specimens after a 1000-h thermal aging at 800 °C in air or humidified hydrogen is reduced by a similar extent of 19%, compared to the counterpart of non-aged joint specimens tested in the same oxidizing or reducing environment.

  15. Evaluating evidence for Cl sources and oxidation chemistry in a coastal, urban environment

    NASA Astrophysics Data System (ADS)

    Young, C. J.; Washenfelder, R. A.; Edwards, P. M.; Parrish, D. D.; Gilman, J. B.; Kuster, W. C.; Mielke, L. H.; Osthoff, H. D.; Tsai, C.; Pikelnaya, O.; Stutz, J.; Veres, P. R.; Roberts, J. M.; Griffith, S.; Dusanter, S.; Stevens, P. S.; Flynn, J.; Grossberg, N.; Lefer, B.; Holloway, J. S.; Peischl, J.; Ryerson, T. B.; Atlas, E. L.; Blake, D. R.; Brown, S. S.

    2013-05-01

    The role of chlorine atoms (Cl) in atmospheric oxidation was traditionally thought to be limited to the marine boundary layer, where they are produced through heterogeneous reactions involving sea salt. However, recent observation of photolytic Cl precursors (ClNO2 and Cl2) formed from anthropogenic pollution has expanded the potential importance of Cl to include coastal and continental urban areas. Measurements of ClNO2 in Los Angeles during CalNex showed it to be an important primary (first generation) radical source. Ratios of volatile organic compounds (VOCs) have been proposed as a sensitive method to quantify Cl oxidation, but have shown little evidence for a significant role of Cl outside of the Arctic. We used a box model with the Master Chemical Mechanism (MCM v3.2) chemistry scheme, constrained by observations in Los Angeles, to examine the Cl-sensitivity of the most commonly used VOC ratios (i-butane, n-butane, and propane) as a function of NOx and secondary radical production. Model results indicated these and faster reacting VOC tracer ratios could not detect the influence of Cl unless the sustained ratio of OH to Cl was below 200. However, the model results also show that secondary (second generation) OH production resulting from Cl oxidation of VOCs is strongly influenced by NOx, and that this effect can obscure the importance of Cl as a primary oxidant. Calculated concentrations of Cl showed a maximum in mid-morning due to a photolytic source from ClNO2 and loss primarily to reactions with VOCs. The OH to Cl ratio was below 200 for approximately three hours in the morning, but Cl oxidation was not evident from the measured ratios of VOCs. Instead, model simulations show that secondary OH production causes VOC ratios to follow the values expected for OH oxidation despite the significant input of primary Cl from ClNO2 photolysis in the morning. Despite the prevalence of secondary OH as an oxidant in Los Angeles, Cl may play an important role in

  16. Psychometric examination and validation of the aggressive driving scale (ADS).

    PubMed

    Zhang, Yiqi; Houston, Rebecca; Wu, Changxu

    2016-07-01

    Aggressive driving behavior is an important cause of traffic accidents. Based on the recent view that aggressive driving is one way that trait aggression manifests itself, a growing research area has focused on the development of scales to assess aggressive driving. The aggressive driving scale (ADS) analyzed in the present study consists of 24 items. A sample of 276 participants was analyzed to obtain the factor structure and reliability of the ADS and 67 of them participated in the behavioral experiment in order to examine the construct and predictive validity of the scale. Results indicated a 3-factor structure (interference with other drivers, violations/risk taking, and anger/aggression expression behavior) with high item loadings. The ADS had high internal consistency and test-retest reliability. Construct validity of the ADS was established as the ADS subscale scores correlated significantly with trait measures of anger and aggression. Predictive validity of the ADS was verified as most items were significantly correlated with behavioral measures derived from a driving simulator. The ADS was a significant predictor of behavioral measures both in the simulated environment (i.e., frequency of driving off the road, red light running behavior, frequency of colliding with a vehicle, frequency and distance of over speeding, frequency and distance of central crossing) and reported real world situations (i.e., annual moving violations and accidents). These results suggest that the ADS is a reliable and valid tool in evaluating aggressive driving behavior as the current study provides behavioral support for the effectiveness of the ADS in measuring aggressive driving behavior. Aggr. Behav. 42:313-323, 2016. © 2016 Wiley Periodicals, Inc. PMID:26848038

  17. Adsorption of carbon monoxide on small aluminum oxide clusters: Role of the local atomic environment and charge state on the oxidation of the CO molecule

    NASA Astrophysics Data System (ADS)

    Ornelas-Lizcano, J. C.; Guirado-López, R. A.

    2015-03-01

    We present extensive density functional theory (DFT) calculations dedicated to analyze the adsorption behavior of CO molecules on small AlxOy± clusters. Following the experimental results of Johnson et al. [J. Phys. Chem. A 112, 4732 (2008)], we consider structures having the bulk composition Al2O3, as well as smaller Al2O2 and Al2O units. Our electron affinity and total energy calculations are consistent with aluminum oxide clusters having two-dimensional rhombus-like structures. In addition, interconversion energy barriers between two- and one-dimensional atomic arrays are of the order of 1 eV, thus clearly defining the preferred isomers. Single CO adsorption on our charged AlxOy± clusters exhibits, in general, spontaneous oxygen transfer events leading to the production of CO2 in line with the experimental data. However, CO can also bind to both Al and O atoms of the clusters forming aluminum oxide complexes with a CO2 subunit. The vibrational spectra of AlxOy + CO2 provides well defined finger prints that may allow the identification of specific isomers. The AlxOy+ clusters are more reactive than the anionic species and the final Al2O+ + CO reaction can result in the production of atomic Al and carbon dioxide as observed from experiments. We underline the crucial role played by the local atomic environment, charge density distribution, and spin-multiplicity on the oxidation behavior of CO molecules. Finally, we analyze the importance of coadsorption and finite temperature effects by performing DFT Born-Oppenheimer molecular dynamics. Our calculations show that CO oxidation on AlxOy+ clusters can be also promoted by the binding of additional CO species at 300 K, revealing the existence of fragmentation processes in line with the ones experimentally inferred.

  18. Early-life experience affects honey bee aggression and resilience to immune challenge.

    PubMed

    Rittschof, Clare C; Coombs, Chelsey B; Frazier, Maryann; Grozinger, Christina M; Robinson, Gene E

    2015-01-01

    Early-life social experiences cause lasting changes in behavior and health for a variety of animals including humans, but it is not well understood how social information ''gets under the skin'' resulting in these effects. Adult honey bees (Apis mellifera) exhibit socially coordinated collective nest defense, providing a model for social modulation of aggressive behavior. Here we report for the first time that a honey bee's early-life social environment has lasting effects on individual aggression: bees that experienced high-aggression environments during pre-adult stages showed increased aggression when they reached adulthood relative to siblings that experienced low-aggression environments, even though all bees were kept in a common environment during adulthood. Unlike other animals including humans however, high-aggression honey bees were more, rather than less, resilient to immune challenge, assessed as neonicotinoid pesticide susceptibility. Moreover, aggression was negatively correlated with ectoparasitic mite presence. In honey bees, early-life social experience has broad effects, but increased aggression is decoupled from negative health outcomes. Because honey bees and humans share aspects of their physiological response to aggressive social encounters, our findings represent a step towards identifying ways to improve individual resiliency. Pre-adult social experience may be crucial to the health of the ecologically threatened honey bee. PMID:26493190

  19. Early-life experience affects honey bee aggression and resilience to immune challenge

    PubMed Central

    Rittschof, Clare C.; Coombs, Chelsey B.; Frazier, Maryann; Grozinger, Christina M.; Robinson, Gene E.

    2015-01-01

    Early-life social experiences cause lasting changes in behavior and health for a variety of animals including humans, but it is not well understood how social information ‘‘gets under the skin’’ resulting in these effects. Adult honey bees (Apis mellifera) exhibit socially coordinated collective nest defense, providing a model for social modulation of aggressive behavior. Here we report for the first time that a honey bee’s early-life social environment has lasting effects on individual aggression: bees that experienced high-aggression environments during pre-adult stages showed increased aggression when they reached adulthood relative to siblings that experienced low-aggression environments, even though all bees were kept in a common environment during adulthood. Unlike other animals including humans however, high-aggression honey bees were more, rather than less, resilient to immune challenge, assessed as neonicotinoid pesticide susceptibility. Moreover, aggression was negatively correlated with ectoparasitic mite presence. In honey bees, early-life social experience has broad effects, but increased aggression is decoupled from negative health outcomes. Because honey bees and humans share aspects of their physiological response to aggressive social encounters, our findings represent a step towards identifying ways to improve individual resiliency. Pre-adult social experience may be crucial to the health of the ecologically threatened honey bee. PMID:26493190

  20. [Gender differences of the influence of an "aggressive" computer game on the variability of the heart rhythm].

    PubMed

    Stepanian, L S; Grigorian, V G; Stepanian, A Iu

    2010-01-01

    The influence of virtual aggressogenic environment on psychoemotional sphere of male and female teenagers with different levels of personal aggression was studied by characteristics of the heart rate. The exposure to the aggressogenic factors produced a change of the centralized control for the autonomic control in female and male teenagers with the high level of aggression and females with the low level of aggression. Male teenagers with the low level of aggression displayed the prevalence of the centralized control. Thus, the influence of exposure of teenagers to the virtual aggressogenic environment was shown to be ambiguous depending on the level of the level of personal aggression and gender. PMID:20469589

  1. An Aggressive Retroperitoneal Fibromatosis

    PubMed Central

    Campara, Zoran; Spasic, Aleksandar; Aleksic, Predrag; Milev, Bosko

    2016-01-01

    Introduction: Aggressive fibromatosis (AF) is a heterogeneous group of mesenchymal tumors that have locally infiltrative growth and a tendency to relapse. The clinical picture is often conditioned by the obstruction of the ureter or small intestine. Diagnosis is based on clinical, radiological and histological parameters. A case report: We report a case of male patient, aged 35 years, with the retroperitoneal fibromatosis. He reported to the physician because of frequent urination with the feeling of pressure and pain. Computed tomography revealed the tumor mass on the front wall of the bladder with diameter of 70mm with signs of infiltration of the musculature of the anterior abdominal wall. Endoscopic transurethral biopsy showed proliferative lesion binders by type of fibromatosis. The tumor was surgically removed in a classical way. The patient feels well and has no recurrence thirty-six months after the operative procedure. Conclusion: The complete tumor resection is the therapeutic choice for the primary tumor as well as for a relapse. PMID:27147794

  2. Colloidal Properties and Stability of Graphene Oxide Nanomaterials in the Aquatic Environment

    EPA Science Inventory

    While graphene oxide (GO) has been found to be the most toxic graphene-based nanomaterial, its environmental fate is still unexplored. In this study, the aggregation kinetics and stability of GO were investigated using time-resolved dynamic light scattering over a wide range of a...

  3. Can Breast Tumors Affect the Oxidative Status of the Surrounding Environment? A Comparative Analysis among Cancerous Breast, Mammary Adjacent Tissue, and Plasma

    PubMed Central

    Panis, C.; Victorino, V. J.; Herrera, A. C. S. A.; Cecchini, A. L.; Simão, A. N. C.; Tomita, L. Y.; Cecchini, R.

    2016-01-01

    In this paper, we investigated the oxidative profile of breast tumors in comparison with their normal adjacent breast tissue. Our study indicates that breast tumors present enhanced oxidative/nitrosative stress, with concomitant augmented antioxidant capacity when compared to the adjacent normal breast. These data indicate that breast cancers may be responsible for the induction of a prooxidant environment in the mammary gland, in association with enhanced TNF-α and nitric oxide. PMID:26697139

  4. Measurement methods for surface oxides on SUS 316L in simulated light water reactor coolant environments using synchrotron XRD and XRF

    NASA Astrophysics Data System (ADS)

    Watanabe, Masashi; Yonezawa, Toshio; Shobu, Takahisa; Shoji, Tetsuo

    2013-03-01

    Synchrotron X-ray diffraction (XRD) and X-ray fluorescent (XRF) measurement techniques have been used for non-destructive characterization of surface oxide films on Type 316L austenitic stainless steels that were exposed to simulated primary water environments of pressurized water reactors (PWR) and boiling water reactors (BWR). The layer structures of the surface spinel oxides were revealed ex situ after oxidation by measurements made as a function of depth. The layer structure of spinel oxides formed in simulated PWR primary water should normally be different from that formed in simulated BWR water. After oxidation in the simulated BWR environment, the spinel oxide was observed to contain NiFe2O4 at shallow depths, and FeCr2O4 and Fe3O4 at deeper depths. By contrast, after oxidation in the simulated PWR primary water environment, a Fe3O4 type spinel was observed near the surface and FeCr2O4 type spinel near the interface with the metal substrate. Furthermore, by in situ measurements during oxidation in the simulated BWR environment, it was also demonstrated that the ratio between spinel and hematite Fe2O3 can be changed depending on the water condition such as BWR normal water chemistry or BWR hydrogen water chemistry.

  5. Genetics of Aggression in Voles

    PubMed Central

    Gobrogge, Kyle L.; Wang, Zuoxin

    2016-01-01

    Prairie voles (Microtus ochrogaster) are socially monogamous rodents that form pair bonds—a behavior composed of several social interactions including attachment with a familiar mate and aggression toward conspecific strangers. Therefore, this species has provided an excellent opportunity for the study of pair bonding behavior and its underlying neural mechanisms. In this chapter, we discuss the utility of this unique animal model in the study of aggression and review recent findings illustrating the neurochemical mechanisms underlying pair bonding-induced aggression. Implications of this research for our understanding of the neurobiology of human violence are also discussed. PMID:22078479

  6. Predicting workplace aggression and violence.

    PubMed

    Barling, Julian; Dupré, Kathryne E; Kelloway, E Kevin

    2009-01-01

    Consistent with the relative recency of research on workplace aggression and the considerable media attention given to high-profile incidents, numerous myths about the nature of workplace aggression have emerged. In this review, we examine these myths from an evidence-based perspective, bringing greater clarity to our understanding of the predictors of workplace aggression. We conclude by pointing to the need for more research focusing on construct validity and prevention issues as well as for methodologies that minimize the likelihood of mono-method bias and that strengthen the ability to make causal inferences. PMID:18793089

  7. The evolution of humor from male aggression

    PubMed Central

    Shuster, Sam

    2012-01-01

    The response to seeing a man riding a unicycle was reported to be consistently related to the viewer’s sex and stage of physical development. To see if this observation was universal, observations of responses were collected from 23 male and 9 female unicyclists aged 15–69 years, with 2–40 years cycling experience across four continents. With two exceptions among men, the findings were the same as those originally reported: children showed interest and curiosity, young girls showed little interest, while adult women showed a kindly, concerned, praising response. By contrast, boys showed physical aggression, which became more verbal, merging in the later teens to the snide, aggressive, stereotyped humorous response shown by adult males, which became less frequent in elderly men. The universality of the response across different individuals, environments, and dates of observation suggests an endogenous mechanism, and the association with masculine development relates this to androgen. The theoretical consequences are discussed. It is concluded that humor develops from aggression in males and is evolutionarily related to sexual selection. PMID:22359467

  8. Family and social environmental factors associated with aggression among Chinese adolescents.

    PubMed

    Dou, Chunxia; Wei, Zhen; Jin, Ke; Wang, He; Wang, Xiulan; Peng, Ziwen

    2015-09-01

    Family and school environments are assumed to be associated with and influence aggressive behaviors. However, which specific risk factors within these environments that are associated with aggressive behavior are unclear. The goal of this study is to identify family and social environmental qualities that are related to aggression among Chinese adolescents. Survey data were obtained from 3,213 randomly selected urban high school students ages 10 through 18 in southern China. Lower parental attachment, higher family income, mother's higher education levels, father's parenting goals, rough or changeable parenting styles, unsuitable peer relationships, and inadequate social atmospheres at school serve as risk factors for aggression among Chinese adolescents. Our findings provide some implications for understanding aggression among adolescents and suggests possible interventions to help overcome potential environmental risk factors and thus to prevent aggressive behavior in school. PMID:25496506

  9. Linking microbial oxidation of arsenic with detection and phylogenetic analysis of arsenite oxidase genes in diverse geothermal environments.

    PubMed

    Hamamura, N; Macur, R E; Korf, S; Ackerman, G; Taylor, W P; Kozubal, M; Reysenbach, A-L; Inskeep, W P

    2009-02-01

    The identification and characterization of genes involved in the microbial oxidation of arsenite will contribute to our understanding of factors controlling As cycling in natural systems. Towards this goal, we recently characterized the widespread occurrence of aerobic arsenite oxidase genes (aroA-like) from pure-culture bacterial isolates, soils, sediments and geothermal mats, but were unable to detect these genes in all geothermal systems where we have observed microbial arsenite oxidation. Consequently, the objectives of the current study were to measure arsenite-oxidation rates in geochemically diverse thermal habitats in Yellowstone National Park (YNP) ranging in pH from 2.6 to 8, and to identify corresponding 16S rRNA and aroA genotypes associated with these arsenite-oxidizing environments. Geochemical analyses, including measurement of arsenite-oxidation rates within geothermal outflow channels, were combined with 16S rRNA gene and aroA functional gene analysis using newly designed primers to capture previously undescribed aroA-like arsenite oxidase gene diversity. The majority of bacterial 16S rRNA gene sequences found in acidic (pH 2.6-3.6) Fe-oxyhydroxide microbial mats were closely related to Hydrogenobaculum spp. (members of the bacterial order Aquificales), while the predominant sequences from near-neutral (pH 6.2-8) springs were affiliated with other Aquificales including Sulfurihydrogenibium spp., Thermocrinis spp. and Hydrogenobacter spp., as well as members of the Deinococci, Thermodesulfobacteria and beta-Proteobacteria. Modified primers designed around previously characterized and newly identified aroA-like genes successfully amplified new lineages of aroA-like genes associated with members of the Aquificales across all geothermal systems examined. The expression of Aquificales aroA-like genes was also confirmed in situ, and the resultant cDNA sequences were consistent with aroA genotypes identified in the same environments. The aroA sequences

  10. Charting the relationship trajectories of aggressive, withdrawn, and aggressive/withdrawn children during early grade school.

    PubMed

    Ladd, G W; Burgess, K B

    1999-01-01

    The premises examined in this longitudinal investigation were that specific behavioral characteristics place children at risk for relationship maladjustment in school environments, and that multiple behavioral risks predispose children to the most severe and prolonged difficulties. Aggressive, withdrawn, and aggressive/withdrawn children were compared to normative and matched control groups on teacher and peer relationship attributes, loneliness, and social satisfaction from kindergarten (M age = 5 years, 7 months; n = 250) through grade 2 (M age = 8.1; n = 242). Children's withdrawn behavior was neither highly stable nor predictive of relational difficulties, as their trajectories resembled the norm except for initially less close and more dependent relationships with teachers. Aggressive behavior was fairly stable, and associated with early-emerging, sustained difficulties including low peer acceptance and conflictual teacher-child relationships. Aggressive/withdrawn children evidenced the most difficulty: compared to children in the normative group, they were consistently more lonely, dissatisfied, friendless, disliked, victimized, and likely to have maladaptive teacher-child relationships. Findings are discussed with respect to recent developments in two prominent literatures: children at-risk and early relationship development. PMID:10446726

  11. Structural characterization of an integral membrane protein in its natural lipid environment by oxidative methionine labeling and mass spectrometry.

    PubMed

    Pan, Yan; Stocks, Bradley B; Brown, Leonid; Konermann, Lars

    2009-01-01

    Membrane proteins represent formidable challenges for many analytical techniques. Studies on these systems are often carried out after surfactant solubilization. Unfortunately, such a non-natural protein environment can affect conformation and stability, and it offers only partial protection against aggregation. This work employs bacteriorhodopsin (BR) as a model system for in situ structural studies on a membrane protein in its natural lipid bilayer. BR-containing purple membrane suspensions were exposed to hydroxyl radicals, generated by nanosecond laser photolysis of dilute aqueous H(2)O(2). The experiments rely on the premise that oxidative labeling occurs mainly at solvent-exposed side chains, whereas sites that are sterically protected will react to a much lesser extent. Following .OH exposure, the protein was analyzed by tryptic peptide mapping and electrospray tandem mass spectrometry. Oxidative labeling of BR was found to occur only at its nine Met residues. This is in contrast to the behavior of previously studied water-soluble proteins, which generally undergo modifications at many different types of residues. In those earlier experiments the high reactivity of Met has hampered its use as a structural probe. In contrast, the Met oxidation pattern observed here is in excellent agreement with the native BR structure. Extensive labeling is seen for Met32, 68, and 163, all of which are located in solvent-exposed loops. The remaining six Met residues are deeply buried and show severalfold less oxidation. Our results demonstrate the usefulness of Met oxidative labeling for structural studies on membrane proteins, especially when considering that many of these species are methionine-rich. The introduction of additional Met residues as conformational probes, as well as in vivo structural investigations, represents exciting future extensions of the methodology described here. PMID:19055344

  12. Study of scale formation on AISI 316L in simulated solid oxide fuel cell bi-polar environments

    SciTech Connect

    Ziomek-Moroz, M.; Covino, Bernard S., Jr.; Cramer, Stephen D.; Holcomb, Gordon R.; Bullard, Sophie J.; Singh , P.; Windisch, C.F., Jr.

    2004-01-01

    Significant progress made towards reducing the operating temperature of solid oxide fuel cells (SOFC) from {approx}1000 C to {approx}600 C is expected to permit the use of metallic materials with substantial cost reduction. One of the components in a SOFC stack to be made of metallic materials is a bipolar separator, also called an interconnect. It provides electrical connection between individual cells and serves as a gas separator to prevent mixing of the fuel and air. At operating temperature, the material selected for interconnects should possess good chemical and mechanical stability in complex fuel and oxidant gaseous environments, good electrical conductivity, and a coefficient of thermal expansion (CTE) that matches that of the cathode, anode, and electrolyte components. Cr2O3 scale-forming alloys appear to be the most promising candidates. There appears to be a mechanism whereby the environment on the fuel side of a stainless steel interconnect changes the corrosion behavior of the metal on the air side. The corrosion behavior of 316L stainless steel simultaneously exposed to air on one side and H2+3%H2O on the other at 907 K was studied using X-ray diffraction (XRD) and Raman spectroscopy. The electrical property of the investigated material was determined in terms of area-specific resistance (ASR). The chemical and electrical properties of 316L exposed to a dual environment of air/ (H2+H2O) were compared to those of 316L exposed to a single environment of air/air.

  13. Environmental factors and aggressive behavior

    SciTech Connect

    Anderson, A.C.

    1982-07-01

    This paper briefly reviews some of the research areas which indicate a correlation between environmental factors and initiation of aggressive behavior. Environmental factors including lunar influences, month of birth, climate and the effects of crowding and certain chemicals are discussed.

  14. Quantifying Aggressive Behavior in Zebrafish.

    PubMed

    Teles, Magda C; Oliveira, Rui F

    2016-01-01

    Aggression is a complex behavior that influences social relationships and can be seen as adaptive or maladaptive depending on the context and intensity of expression. A model organism suitable for genetic dissection of the underlying neural mechanisms of aggressive behavior is still needed. Zebrafish has already proven to be a powerful vertebrate model organism for the study of normal and pathological brain function. Despite the fact that zebrafish is a gregarious species that forms shoals, when allowed to interact in pairs, both males and females express aggressive behavior and establish dominance hierarchies. Here, we describe two protocols that can be used to quantify aggressive behavior in zebrafish, using two different paradigms: (1) staged fights between real opponents and (2) mirror-elicited fights. We also discuss the methodology for the behavior analysis, the expected results for both paradigms, and the advantages and disadvantages of each paradigm in face of the specific goals of the study. PMID:27464816

  15. Aggression in borderline personality disorder.

    PubMed

    Látalová, K; Prasko, J

    2010-09-01

    This review examined aggressive behavior in Borderline Personality Disorder (BPD) and its management in adults. Aggression against self or against others is a core component of BPD. Impulsiveness is a clinical hallmark (as well as a DSM-IV-TR diagnostic criterion) of BPD, and aggressive acts by BPD patients are largely of the impulsive type. BPD has high comorbidity rates with substance use disorders, Bipolar Disorder, and Antisocial Personality Disorder; these conditions further elevate the risk for violence. Treatment of BDP includes psychodynamic, cognitive behavioral, schema therapy, dialectic behavioral, group and pharmacological interventions. Recent studies indicate that many medications, particularly atypical antipsychotics and anticonvulsants, may reduce impulsivity, affective lability as well as irritability and aggressive behavior. But there is still a lack of large, double blind, placebo controlled studies in this area. PMID:20390357

  16. Role of metabolic environment on nitric oxide mediated inhibition of neointimal hyperplasia in type 1 and type 2 diabetes.

    PubMed

    Rodriguez, Monica P; Emond, Zachary M; Wang, Zheng; Martinez, Janet; Jiang, Qun; Kibbe, Melina R

    2014-01-30

    Nitric oxide (NO) is well known to inhibit neointimal hyperplasia following arterial injury. Previously, we reported that NO was more effective at inhibiting neointimal hyperplasia in a type 2 diabetic environment than control. We also found that NO was ineffective in an uncontrolled type 1 diabetic environment; however, insulin restored the efficacy of NO. Thus, the goal of this study was to more closely evaluate the effect of insulin and glucose on the efficacy of NO at inhibiting neointimal hyperplasia in both type 1 and type 2 diabetic environments using different doses of insulin as well as pioglitazone. Type 1 diabetes was induced in male lean Zucker (LZ) rats with streptozotocin (60 mg/kg IP). Groups included control, moderate glucose control, and tight glucose control. Zucker diabetic fatty (ZDF) rats fed Purina 5008 chow were used as a type 2 diabetic model. Groups included no therapy, insulin therapy, or pioglitazone therapy. After 4 weeks of maintaining group assignments, the carotid artery injury model was performed. Treatment groups included: control, injury and injury plus NO. 2 weeks following arterial injury, in the type 1 diabetic rats, NO most effectively reduced the neointimal area in the moderate and tightly controlled groups (81% and 88% vs. 33%, respectively, p=0.01). In type 2 diabetic rats, the metabolic environment had no impact on the efficacy of NO (81-82% reduction for all groups). Thus, in this study, we show NO is effective at inhibiting neointimal hyperplasia in both type 1 and type 2 diabetic environments. A greater understanding of how the metabolic environment may impact the efficacy of NO may lead to the development of more effective NO-based therapies for patients with diabetes. PMID:24333562

  17. Neurotensin inversely modulates maternal aggression.

    PubMed

    Gammie, S C; D'Anna, K L; Gerstein, H; Stevenson, S A

    2009-02-18

    Neurotensin (NT) is a versatile neuropeptide involved in analgesia, hypothermia, and schizophrenia. Although NT is released from and acts upon brain regions involved in social behaviors, it has not been linked to a social behavior. We previously selected mice for high maternal aggression (maternal defense), an important social behavior that protects offspring, and found significantly lower NT expression in the CNS of highly protective females. Our current study directly tested NT's role in maternal defense. Intracerebroventricular (i.c.v.) injections of NT significantly impaired defense in terms of time aggressive and number of attacks at all doses tested (0.05, 0.1, 1.0, and 3.0 microg). Other maternal behaviors, including pup retrieval, were unaltered following NT injections (0.05 microg) relative to vehicle, suggesting specificity of NT action on defense. Further, i.c.v. injections of the NT receptor 1 (NT1) antagonist, SR 48692 (30 microg), significantly elevated maternal aggression in terms of time aggressive and attack number. To understand where NT may regulate aggression, we examined Fos following injection of either 0.1 microg NT or vehicle. Thirteen of 26 brain regions examined exhibited significant Fos increases with NT, including regions expressing NT1 and previously implicated in maternal aggression, such as lateral septum, bed nucleus of stria terminalis, paraventricular nucleus, and central amygdala. Together, our results indicate that NT inversely regulates maternal aggression and provide the first direct evidence that lowering of NT signaling can be a mechanism for maternal aggression. To our knowledge, this is the first study to directly link NT to a social behavior. PMID:19118604

  18. An ultra-high temperature testing instrument under oxidation environment up to 1800 °C.

    PubMed

    Cheng, Xiangmeng; Qu, Zhaoliang; He, Rujie; Ai, Shigang; Zhang, Rubing; Pei, Yongmao; Fang, Daining

    2016-04-01

    A new testing instrument was developed to measure the high-temperature constitutive relation and strength of materials under an oxidative environment up to 1800 °C. A high temperature electric resistance furnace was designed to provide a uniform temperature environment for the mechanical testing, and the temperature could vary from room temperature (RT) to 1800 °C. A set of semi-connected grips was designed to reduce the stress. The deformation of the specimen gauge section was measured by a high temperature extensometer. The measured results were acceptable compared with the results from the strain gauge method. Meanwhile, tensile testing of alumina was carried out at RT and 800 °C, and the specimens showed brittle fracture as expected. The obtained Young's modulus was in agreement with the reported value. In addition, tensile experiment of ZrB2-20%SiC ceramic was conducted at 1700 °C and the high-temperature tensile stress-strain curve was first obtained. Large plastic deformation up to 0.46% and the necking phenomenon were observed before the fracture of specimen. This instrument will provide a powerful research tool to study the high temperature mechanical property of materials under oxidation and is benefit for the engineering application of materials in aerospace field. PMID:27131708

  19. Thermodynamics and Kinetics of Sulfide Oxidation by Oxygen: A Look at Inorganically Controlled Reactions and Biologically Mediated Processes in the Environment

    PubMed Central

    Luther, George W.; Findlay, Alyssa J.; MacDonald, Daniel J.; Owings, Shannon M.; Hanson, Thomas E.; Beinart, Roxanne A.; Girguis, Peter R.

    2011-01-01

    The thermodynamics for the first electron transfer step for sulfide and oxygen indicates that the reaction is unfavorable as unstable superoxide and bisulfide radical ions would need to be produced. However, a two-electron transfer is favorable as stable S(0) and peroxide would be formed, but the partially filled orbitals in oxygen that accept electrons prevent rapid kinetics. Abiotic sulfide oxidation kinetics improve when reduced iron and/or manganese are oxidized by oxygen to form oxidized metals which in turn oxidize sulfide. Biological sulfur oxidation relies on enzymes that have evolved to overcome these kinetic constraints to affect rapid sulfide oxidation. Here we review the available thermodynamic and kinetic data for H2S and HS• as well as O2, reactive oxygen species, nitrate, nitrite, and NOx species. We also present new kinetic data for abiotic sulfide oxidation with oxygen in trace metal clean solutions that constrain abiotic rates of sulfide oxidation in metal free solution and agree with the kinetic and thermodynamic calculations. Moreover, we present experimental data that give insight on rates of chemolithotrophic and photolithotrophic sulfide oxidation in the environment. We demonstrate that both anaerobic photolithotrophic and aerobic chemolithotrophic sulfide oxidation rates are three or more orders of magnitude higher than abiotic rates suggesting that in most environments biotic sulfide oxidation rates will far exceed abiotic rates due to the thermodynamic and kinetic constraints discussed in the first section of the paper. Such data reshape our thinking about the biotic and abiotic contributions to sulfide oxidation in the environment. PMID:21833317

  20. TRANSFORMATION AND FATE OF MANUFACTURED METAL OXIDE AND METAL NANOPARTICLES IN AQUEOUS ENVIRONMENTS

    EPA Science Inventory

    As commercial manufactured nanomaterials become more commonplace, we can expect that these manufactured materials have the potential to get into the environment sometime during production, distribution, use or disposal, i.e. sometime during the lifecycle of these materials. In...

  1. The Application of an Adaptive, Web-Based Learning Environment on Oxidation-Reduction Reactions

    ERIC Educational Resources Information Center

    Own, Zangyuan

    2006-01-01

    The World Wide Web is increasingly being used as a vehicle for flexible learning, where learning is seen to be free from time, geographical, and participation constraints. In addition to flexibility, the Web facilitates student-centered approaches, creating a motivating and active learning environment. The purpose of this study is to set up an…

  2. Effect of co-existing kaolinite and goethite on the aggregation of graphene oxide in the aquatic environment.

    PubMed

    Huang, Guanxing; Guo, Huiyuan; Zhao, Jian; Liu, Yonghong; Xing, Baoshan

    2016-10-01

    Broad applications of graphene oxide (GO) will result in the release of GO into aquatic environments, where clay minerals and metal (hydr)oxides are commonly present. Thereby the interactions between GO and a binary system containing clay minerals and metal (hydr)oxides can occur. We investigated the aggregation of GO with kaolinite and kaolinite-goethite associations (KGAs) in aquatic systems under different pHs, ionic strengths, and GO concentrations. GO suspension was unstable at low pHs, and the aggregation of GO occurred in the presence of KGA-4% and KGA-10% until pH 5 and 6, respectively. Kaolinite decreased the critical coagulation concentration (CCC) of GO at pH 5.5 from around 50 to 20 mM NaCl due to the reduced energy barrier. Heteroaggregation of GO with KGAs was extremely sensitive to ionic strength at pH 5.5, and the CCC of GO in the presence of KGA-10% increased from less than 1 mM NaCl to 5 mM NaCl with the increase of pH from 5.5 to 9. The heteroaggregation extent of GO with KGAs was enhanced firstly, then reduced with the increase of GO concentrations at pH 5.0, which is likely because KGA plates were more efficiently wrapped by large-size GO sheets with increasing GO concentrations. These findings are useful for understanding and predicting the fate of GO in the relatively complicated aquatic and soil environments where binary minerals co-exist. PMID:27379727

  3. Differences in nitrite-oxidizing communities and kinetics in a brackish environment after enrichment at low and high nitrite concentrations.

    PubMed

    Tangkitjawisut, Wipasanee; Limpiyakorn, Tawan; Powtongsook, Sorawit; Pornkulwat, Preeyaporn; Suwannasilp, Benjaporn Boonchayaanant

    2016-04-01

    Nitrite accumulation in shrimp ponds can pose serious adverse effects to shrimp production and the environment. This study aims to develop an effective process for the enrichment of ready-to-use nitrite-oxidizing bacteria (NOB) inocula that would be appropriate for nitrite removal in brackish shrimp ponds. To achieve this objective, the effects of nitrite concentrations on NOB communities and nitrite oxidation kinetics in a brackish environment were investigated. Moving-bed biofilm sequencing batch reactors and continuous moving-bed biofilm reactors were used for the enrichment of NOB at various nitrite concentrations, using sediment from brackish shrimp ponds as seed inoculum. The results from NOB population analysis with quantitative polymerase chain reaction (qPCR) show that only Nitrospira were detected in the sediment from the shrimp ponds. After the enrichment, both Nitrospira and Nitrobacter coexisted in the reactors controlling effluent nitrite at 0.1 and 0.5 mg-NO2(-)-N/L. On the other hand, in the reactors controlling effluent nitrite at 3, 20, and 100 mg-NO2(-)-N/L, Nitrobacter outcompeted Nitrospira in many orders of magnitude. The half saturation coefficients (Ks) for nitrite oxidation of the enrichments at low nitrite concentrations (0.1 and 0.5 mg-NO2(-)-N/L) were in the range of 0.71-0.98 mg-NO2(-)-N/L. In contrast, the K(s) values of NOB enriched at high nitrite concentrations (3, 20, and 100 mg-NO2(-)-N/L) were much higher (8.36-12.20 mg-NO2(-)-N/L). The results suggest that the selection of nitrite concentrations for the enrichment of NOB inocula can significantly influence NOB populations and kinetics, which could affect the effectiveness of their applications in brackish shrimp ponds. PMID:27090693

  4. Normative beliefs about aggression and cyber aggression among young adults: a longitudinal investigation.

    PubMed

    Wright, Michelle F; Li, Yan

    2013-01-01

    This longitudinal study examined normative beliefs about aggression (e.g., face-to-face, cyber) in relation to the engagement in cyber aggression 6 months later among 126 (69 women) young adults. Participants completed electronically administered measures assessing their normative beliefs, face-to-face and cyber aggression at Time 1, and cyber aggression 6 months later (Time 2). We found that men reported more cyber relational and verbal aggression when compared to women. After controlling for each other, Time 1 face-to-face relational aggression was positively related to Time 2 cyber relational aggression, whereas Time 1 face-to-face verbal aggression was positively related to Time 2 cyber verbal aggression. Normative beliefs regarding cyber aggression was positively related to both forms of cyber aggression 6 months later, after controlling for normative beliefs about face-to-face aggression. Furthermore, a significant two-way interaction between Time 1 cyber relational aggression and normative beliefs about cyber relational aggression was found. Follow-up analysis showed that Time 1 cyber relational aggression was more strongly related to Time 2 cyber relational aggression when young adults held higher normative beliefs about cyber relational aggression. A similar two-way interaction was found for cyber verbal aggression such that the association between Time 1 and Time 2 cyber verbal aggression was stronger at higher levels of normative beliefs about cyber verbal aggression. Results are discussed in terms of the social cognitive and behavioral mechanisms associated with the engagement of cyber aggression. PMID:23440595

  5. Numerical Modeling of Oxidized 2D C/SiC Composites in Air Environments Below 900 °C: Microstructure and Elastic Properties

    NASA Astrophysics Data System (ADS)

    Sun, Zhigang; Chen, Xihui; Shao, Hongyan; Song, Yingdong

    2016-08-01

    A numerical model is presented for simulation of the oxidation-affected behaviors of two dimensional carbon fiber-reinforced silcon carbide matrix composite (2D C/SiC) exposed to air oxidizing environments below 900 °C, which incorporates the modeling of oxidized microstructure and computing of degraded elastic properties. This model is based upon the analysis of the representative volume cell (RVC) of the composite. The multi-scale model of 2D C/SiC composites is concerned in the present study. Analysis results of such a composite can provide a guideline for the real 2D C/SiC composite. The micro-structure during oxidation process is firstly modeled in the RVC. The elastic moduli of oxidized composite under non-stress oxidation environment is computed by finite element analysis. The elastic properties of 2D-C/SiC composites in air oxidizing environment are evaluated and validated in comparison to experimental data. The oxidation time, temperature and fiber volume fractions of C/SiC composite are investigated to show their influences upon the elastic properties of 2D C/SiC composites.

  6. Numerical Modeling of Oxidized 2D C/SiC Composites in Air Environments Below 900 °C: Microstructure and Elastic Properties

    NASA Astrophysics Data System (ADS)

    Sun, Zhigang; Chen, Xihui; Shao, Hongyan; Song, Yingdong

    2016-04-01

    A numerical model is presented for simulation of the oxidation-affected behaviors of two dimensional carbon fiber-reinforced silcon carbide matrix composite (2D C/SiC) exposed to air oxidizing environments below 900 °C, which incorporates the modeling of oxidized microstructure and computing of degraded elastic properties. This model is based upon the analysis of the representative volume cell (RVC) of the composite. The multi-scale model of 2D C/SiC composites is concerned in the present study. Analysis results of such a composite can provide a guideline for the real 2D C/SiC composite. The micro-structure during oxidation process is firstly modeled in the RVC. The elastic moduli of oxidized composite under non-stress oxidation environment is computed by finite element analysis. The elastic properties of 2D-C/SiC composites in air oxidizing environment are evaluated and validated in comparison to experimental data. The oxidation time, temperature and fiber volume fractions of C/SiC composite are investigated to show their influences upon the elastic properties of 2D C/SiC composites.

  7. The changing oxidizing environment in London - trends in ozone precursors and their contribution to ozone production

    NASA Astrophysics Data System (ADS)

    von Schneidemesser, E.; Vieno, M.; Monks, P. S.

    2014-01-01

    Ground-level ozone is recognized to be a threat to human health (WHO, 2003), have a deleterious impact on vegetation (Fowler et al., 2009), is also an important greenhouse gas (IPCC, 2007) and key to the oxidative ability of the atmosphere (Monks et al., 2009). Owing to its harmful effect on health, much policy and mitigation effort has been put into reducing its precursors - the nitrogen oxides (NOx) and non-methane volatile organic compounds (NMVOCs). The non-linear chemistry of tropospheric ozone formation, dependent mainly on NOx and NMVOC concentrations in the atmosphere, makes controlling tropospheric ozone complex. Furthermore, the concentration of ozone at any given point is a complex superimposition of in-situ produced or destroyed ozone and transported ozone on the regional and hemispheric-scale. In order to effectively address ozone, a more detailed understanding of its origins is needed. Here we show that roughly half (5 μg m-3) of the observed increase in urban (London) ozone (10 μg m-3) in the UK from 1998 to 2008 is owing to factors of local origin, in particular, the change in NO : NO2 ratio, NMVOC : NOx balance, NMVOC speciation, and emission reductions (including NOx titration). In areas with previously higher large concentrations of nitrogen oxides, ozone that was previously suppressed by high concentrations of NO has now been "unmasked", as in London and other urban areas of the UK. The remaining half (approximately 5 μg m-3) of the observed ozone increase is attributed to non-local factors such as long-term transport of ozone, changes in background ozone, and meteorological variability. These results show that a two-pronged approach, local action and regional-to-hemispheric cooperation, is needed to reduce ozone and thereby population exposure, which is especially important for urban ozone.

  8. Mantle oxidation state and its relationship to tectonic environment and fluid speciation.

    PubMed

    Wood, B J; Bryndzia, L T; Johnson, K E

    1990-04-20

    The earth's mantle is degassed along mid-ocean ridges, while rehydration and possibly recarbonaton occurs at subduction zones. These processes and the speciation of C-H-O fluids in the mantle are related to the oxidation state of mantle peridotite. Peridotite xenoliths from continental localities exhibit an oxygen fugacity (fo(2)) range from -1.5 to +1.5 log units relative to the FMQ (fayalite-magnetite-quartz) buffer. The lowest values are from zones of continental extension. Highly oxidized xenoliths (fo(2) greater than FMQ) come from regions of recent or acive subduction (for example, Ichinomegata, Japan), are commonly amphibole-bearing, and show trace element and isotopic evidence of fluid-rock interaction. Peridotites from ocean ridges are reduced and have an averae fo(2) of about -0.9 log units relative to FMQ, virtually coincident with values obtained from mid-ocean ridge basalt (MORB) glasses. These data are further evidence of the genetic link between MORB liquids and residual peridotite and indicate that the asthenosphere, although reducing, has CO(2) and H(2)O as its major fluid species. Incorporation of oxidized material from subduction zones into the continental lithosphere produces xenoliths that have both asthenospheric and subduction signatures. Fluids in the lithosphere are also dominated by CO(2) and H(2)O, and native C is generally unstable. Although the occurrence of native C (diamond) in deep-seated garnetiferous xenoliths and kimberlites does not require reducing conditions, calculations indicate that high Fe(3+) contents are stabilized in the garnet structure and that fo(2) deareases with increasing depth. PMID:17784487

  9. Agricultural management and environment controls long-term soil nitrous oxide fluxes

    NASA Astrophysics Data System (ADS)

    Gelfand, I.; Shcherbak, I.; Robertson, G. P.

    2013-12-01

    Nitrous oxide (N2O) is an important greenhouse gas with a long atmospheric half-life. Understanding the controls on soil nitrous oxide fluxes is vital for the development of mitigation opportunities and for understanding their climatic impact. The spatial and temporal variability of soil nitrous oxide fluxes, however, makes it difficult to predict such fluxes. We examined the longest available dataset, 22 years of continues measurements, which contains biweekly measurements of soil nitrous oxide emissions together with measurements of an array of environmental and management parameters from eleven ecosystems, including four corn-soybean-wheat rotations under different management (conventional, no-till, biological, and reduced input), one perennial alfalfa system, two tree plantations, three successional systems, and one deciduous forest. This dataset was used to assess the effect of different agricultural and land management practices on soil N2O emissions. Using statistical and correlation analyses, we found that, in general, annual crops emitted 2-3 times more N2O annually than did perennial crops. Among the annual crops, there were no differences in the annual emissions among the cropping systems; the conventional, no-till, reduced input, and biologically managed systems emitted similar amounts of N2O with very different emission patterns. Among the perennial crops, alfalfa emitted 2 times more N2O than did poplar, approximately 1.6 times more than did the coniferous plantation, and ~3 times more than did the unmanaged successional communities and the deciduous forest, which emitted similar amounts. Within the annual crop rotation phases, the wheat phase of the conventionally and no-till-managed rotations emitted approximately twice as much N2O than did the reduced input- and biologically managed systems, largely due to the length of the bare soil fallow. The corn and soybean phases of the conventionally managed rotation emitted between 70 and 100% less N2O than

  10. Surface chemical heterogeneity of bacteriogenic iron oxides from a subterranean environment.

    PubMed

    Martinez, Raul E; Smith, D Scott; Pedersen, Karsten; Ferris, F Grant

    2003-12-15

    This study quantifies the surface chemical heterogeneity of bacteriogenic iron oxides (BIOS) and its end-members (2-line ferrihydrite and intermixed intact and fragmented bacteria). On a dry weight basis, BIOS consisted of 64.5 +/- 1.8% ferrihydrite and 34.5 +/- 1.8% organic matter. Enrichment of Al, Cu, Cr, Mn, Sr, and Zn was shown in the solid versus the aqueous phase (1.9 < log Kd < 4.2). Within the solid-phase Al (69.5%), Cu (78.7%), and Zn (77.9%) were associated with the bacteria, whereas Cr (59.8%), Mn (99.8%), and Sr (79.4%) preferred ferrihydrite. Acid-base titration data from the BIOS and bacteria were fitted using FOCUS pKa spectroscopy. The bacteria spectrum with pKa's of 4.18 +/- 0.37, 4.80 +/- 0.54, 6.98 +/- 0.45, and 9.75 +/- 0.68 was similar to discrete and continuous spectra for intact and fragmented bacteria. The BIOS spectrum recorded pKa's of 4.27 +/- 0.51, 6.61 +/- 0.51, 7.89 +/- 1.10, and 9.65 +/- 0.66 and was deconvoluted to remove overlapping binding site contributions from the bacteria. The resulting residual iron oxide spectrum coincided with discrete MUSIC spectra for goethite and lepidocrocite with pKa values of 4.10 +/- 0.43, 6.53 +/- 0.45, 7.81 +/- 0.76, and 9.51 +/- 0.68. Surface site density analysis showed that acidic sites (pKa < 6) were contributed by the bacteria (37%), whereas neutral sites (6 < pKa < 8) were characteristic of the iron oxide fraction (35%). Basic sites (8 < pKa) were higher in the bacteria (57%), than in the BIOS (44%) or iron oxide fractions (47%). This analysis suggested a high degree of bacterial group masking and a similarity between the BIOS and goethite surface reactivity. An understanding of the BIOS surface chemical heterogeneity and inherent proton and metal binding capacity was obtained through the use of FOCUS apparent pKa spectroscopy. PMID:14717179

  11. Adolescents' Social Reasoning about Relational Aggression

    ERIC Educational Resources Information Center

    Goldstein, Sara E.; Tisak, Marie S.

    2010-01-01

    We examined early adolescents' reasoning about relational aggression, and the links that their reasoning has to their own relationally aggressive behavior. Thinking about relational aggression was compared to thinking about physical aggression, conventional violations, and personal behavior. In individual interviews, adolescents (N = 103) rated…

  12. The Development of Aggression within Sibling Conflict.

    ERIC Educational Resources Information Center

    Martin, Jacqueline L.; Ross, Hildy S.

    1995-01-01

    A longitudinal study examined responses to physically aggressive conflicts among siblings. Found that parents respond to half of children's aggression (especially if there is crying). Most parent and child responses were simple commands to stop the aggression. Reasoning was used less often, and physical intervention, rarely. Aggression was higher…

  13. Do Teachers Misbehave? Aggression in School Teams

    ERIC Educational Resources Information Center

    Ben Sasson, Dvora; Somech, Anit

    2015-01-01

    Purpose: Despite growing research on school aggression, significant gaps remain in the authors' knowledge of team aggression, since most studies have mainly explored aggression on the part of students. The purpose of this paper is to focus on understanding the phenomenon of workplace aggression in school teams. Specifically, the purpose of the…

  14. Attributional bias and reactive aggression.

    PubMed

    Hudley, C; Friday, J

    1996-01-01

    This article looks at a cognitive behavioral intervention designed to reduce minority youths' (Latino and African-American boys) levels of reactive peer-directed aggression. The BrainPower Program trains aggressive boys to recognize accidental causation in ambiguous interactions with peers. The objective of this research is to evaluate the effectiveness of this attribution retraining program in reducing levels of reactive, peer-directed aggression. This research hypothesizes that aggressive young boys' tendency to attribute hostile intentions to others in ambiguous social interactions causes display of inappropriate, peer-directed aggression. A reduction in attributional bias should produce a decrease in reactive physical and verbal aggression directed toward peers. A 12-session, attributional intervention has been designed to reduce aggressive students' tendency to infer hostile intentions in peers following ambiguous peer provocations. The program trains boys to (1) accurately perceive and categorize the available social cues in interactions with peers, (2) attribute negative outcomes of ambiguous causality to accidental or uncontrollable causes, and (3) generate behaviors appropriate to these retrained attributions. African-American and Latino male elementary-school students (N = 384), in grades four-six, served as subjects in one of three groups: experimental attribution retraining program, attention training, and no-attention control group. Three broad categories of outcome data were collected: teacher and administrator reports of behavior, independent observations of behavior, and self-reports from participating students. Process measures to assess implementation fidelity include videotaped training sessions, observations of intervention sessions, student attendance records, and weekly team meetings. The baseline data indicated that students who were evenly distributed across the four sites were not significantly different on the baseline indicators: student

  15. Molecular mechanism of water oxidation in photosynthesis based on the functioning of manganese in two different environments

    PubMed Central

    Kambara, T.; Govindjee

    1985-01-01

    We present a model of photosynthetic water oxidation that utilizes the property of higher-valent Mn ions in two different environments and the characteristic function of redox-active ligands to explain all known aspects of electron transfer from H2O to Z, the electron donor to P680, the photosystem II reaction center chlorophyll a. There are two major features of this model. (i) The four functional Mn atoms are divided into two groups of two Mn each: [Mn] complexes in a hydrophobic cavity in the intrinsic 34-kDa protein; and (Mn) complexes on the hydrophilic surface of the extrinsic 33-kDa protein. The oxidation of H2O is carried out by two [Mn] complexes, and the protons are transferred from a [Mn] complex to a (Mn) complex along the hydrogen bond between their respective ligand H2O molecules. (ii) Each of the two [Mn] ions binds one redox-active ligand (RAL), such as a quinone (alternatively, an aromatic amino acid residue). Electron transfer occurs from the reduced RAL to the oxidized Z. When the experimental data concerning atomic structure of the water-oxidizing center (WOC), electron transfer between the WOC and Z, the electronic structure of the WOC, the proton-release pattern, and the effect of Cl- are compared with the predictions of the model, satisfactory qualitative and, in many instances, quantitative agreements are obtained. In particular, this model clarifies the origin of the observed absorption-difference spectra, which have the same pattern in all S-state transitions, and of the effect of Cl--depletion on the S states. PMID:16593603

  16. Arsenite and ferrous iron oxidation linked to chemolithotrophic denitrification for the immobilization of arsenic in anoxic environments

    USGS Publications Warehouse

    Sun, W.; Sierra-Alvarez, R.; Milner, L.; Oremland, R.; Field, J.A.

    2009-01-01

    The objective of this study was to explore a bioremediation strategy based on injecting NO3- to support the anoxic oxidation of ferrous iron (Fe(II)) and arsenite (As(III)) in the subsurface as a means to immobilize As in the form of arsenate (As(V)) adsorbed onto biogenic ferric (Fe(III)) (hydr)oxides. Continuous flows and filled columns were used to simulate a natural anaerobic groundwater and sediment system with co-occurring As(III) and Fe(II) in the presence (column SF1) or absence (column SF2) of nitrate, respectively. During operation for 250 days, the average influent arsenic concentration of 567 ??g L-1 was reduced to 10.6 (??9.6) ??g L-1 in the effluent of column SF1. The cumulative removal of Fe(II) and As(III) in SF1 was 6.5 to 10-fold higher than that in SF2. Extraction and measurement of the mass of iron and arsenic immobilized on the sand packing of the columns were close to the iron and arsenic removed from the aqueous phase during column operation. The dominant speciation of the immobilized iron and arsenic was Fe(III) and As(V) in SF1, compared with Fe(II) and As(III) in SF2. The speciation was confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results indicate that microbial oxidation of As(III) and Fe(II) linked to denitrification resulted in the enhanced immobilization of aqueous arsenic in anaerobic environments by forming Fe(III) (hydr)oxide coated sands with adsorbed As(V). ?? 2009 American Chemical Society.

  17. Effect of functional groups on the crystallization of ferric oxides/oxyhydroxides in suspension environment

    NASA Astrophysics Data System (ADS)

    Zhou, Qiong; Albert, Olga; Deng, Hua; Yu, Xiao-Long; Cao, Yang; Li, Jian-Bao; Huang, Xin

    2012-12-01

    This paper investigated the effects of five kinds of Au surfaces terminated with and without functional groups on the crystallization of ferric oxides/oxyhydroxides in the suspension condition. Self-assembled monolayers (SAMs) were used to create hydroxyl (-OH), carboxyl (-COOH), amine (-NH2) and methyl (-CH3) functionalized surfaces, which proved to be of the same surface density. The immersion time of substrates in the Fe(OH)3 suspension was divided into two time portions. During the first period of 2 h, few ferric oxide/oxyhydroxide was deposited except that ɛ-Fe2O3 was detected on -NH2 surface. Crystallization for 10 h evidenced more kinds of iron compounds on the functional surfaces. Goethite and maghemite were noticed on four functional surfaces, and maghemite also grew on Au surface. Deposition of ɛ-Fe2O3 was found on -OH surface, while the growth of orthorhombic and hexagon FeOOH were indicated on -NH2 surface. Considering the wide existence of iron compounds in nature, our investigation is a precedent work to the study of iron biomineralization in the suspension area.

  18. The Metabolic Syndrome, Oxidative Stress, Environment, and Cardiovascular Disease: The Great Exploration

    PubMed Central

    Hutcheson, Rebecca; Rocic, Petra

    2012-01-01

    The metabolic syndrome affects 30% of the US population with increasing prevalence. In this paper, we explore the relationship between the metabolic syndrome and the incidence and severity of cardiovascular disease in general and coronary artery disease (CAD) in particular. Furthermore, we look at the impact of metabolic syndrome on outcomes of coronary revascularization therapies including CABG, PTCA, and coronary collateral development. We also examine the association between the metabolic syndrome and its individual component pathologies and oxidative stress. Related, we explore the interaction between the main external sources of oxidative stress, cigarette smoke and air pollution, and metabolic syndrome and the effect of this interaction on CAD. We discuss the apparent lack of positive effect of antioxidants on cardiovascular outcomes in large clinical trials with emphasis on some of the limitations of these trials. Finally, we present evidence for successful use of antioxidant properties of pharmacological agents, including metformin, statins, angiotensin II type I receptor blockers (ARBs), and angiotensin II converting enzyme (ACE) inhibitors, for prevention and treatment of the cardiovascular complications of the metabolic syndrome. PMID:22829804

  19. Low energy SIMS characterization of passive oxide films formed on a low-nickel stainless steel in alkaline media

    NASA Astrophysics Data System (ADS)

    Fajardo, S.; Bastidas, D. M.; Ryan, M. P.; Criado, M.; McPhail, D. S.; Morris, R. J. H.; Bastidas, J. M.

    2014-01-01

    Low-energy secondary ion mass spectrometry (SIMS) was used to study the oxide films formed on a low-nickel austenitic stainless steel (SS), potential replacement to conventional AISI 304 SS in reinforced concrete structures (RCS) that are subjected to aggressive environments. The effect of carbonation and the presence of chloride ions were studied. The oxide films formed a chemically gradated bi-layer structure with an outer layer predominately constituted by iron oxides and an inner layer enriched in chromium oxides. Chloride ions were not found in the oxide film but did have an effect on film structure and thickness.

  20. Adsorption of carbon monoxide on small aluminum oxide clusters: Role of the local atomic environment and charge state on the oxidation of the CO molecule

    SciTech Connect

    Ornelas-Lizcano, J. C.; Guirado-López, R. A.

    2015-03-28

    We present extensive density functional theory (DFT) calculations dedicated to analyze the adsorption behavior of CO molecules on small Al{sub x}O{sub y}{sup ±} clusters. Following the experimental results of Johnson et al. [J. Phys. Chem. A 112, 4732 (2008)], we consider structures having the bulk composition Al{sub 2}O{sub 3}, as well as smaller Al{sub 2}O{sub 2} and Al{sub 2}O units. Our electron affinity and total energy calculations are consistent with aluminum oxide clusters having two-dimensional rhombus-like structures. In addition, interconversion energy barriers between two- and one-dimensional atomic arrays are of the order of 1 eV, thus clearly defining the preferred isomers. Single CO adsorption on our charged Al{sub x}O{sub y}{sup ±} clusters exhibits, in general, spontaneous oxygen transfer events leading to the production of CO{sub 2} in line with the experimental data. However, CO can also bind to both Al and O atoms of the clusters forming aluminum oxide complexes with a CO{sub 2} subunit. The vibrational spectra of Al{sub x}O{sub y} + CO{sub 2} provides well defined finger prints that may allow the identification of specific isomers. The Al{sub x}O{sub y}{sup +} clusters are more reactive than the anionic species and the final Al{sub 2}O{sup +} + CO reaction can result in the production of atomic Al and carbon dioxide as observed from experiments. We underline the crucial role played by the local atomic environment, charge density distribution, and spin-multiplicity on the oxidation behavior of CO molecules. Finally, we analyze the importance of coadsorption and finite temperature effects by performing DFT Born-Oppenheimer molecular dynamics. Our calculations show that CO oxidation on Al{sub x}O{sub y}{sup +} clusters can be also promoted by the binding of additional CO species at 300 K, revealing the existence of fragmentation processes in line with the ones experimentally inferred.

  1. Kindergarten Children's Genetic Vulnerabilities Interact with Friends' Aggression to Promote Children's Own Aggression

    ERIC Educational Resources Information Center

    van Lier, Pol; Boivin, Michel; Dionne, Ginette; Vitaro, Frank; Brendgen, Mara; Koot, Hans; Tremblay, Richard E.; Perusse, Daniel

    2007-01-01

    Objective: To examine whether kindergarten children's genetic liability to physically aggress moderates the contribution of friends' aggression to their aggressive behaviors. Method: Teacher and peer reports of aggression were available for 359 6-year-old twin pairs (145 MZ, 212 DZ) as well as teacher and peer reports of aggression of the two best…

  2. Examining Genetic and Environmental Effects on Social Aggression: A Study of 6-Year-Old Twins

    ERIC Educational Resources Information Center

    Brendgen, Mara; Dionne, Ginette; Girard, Alain; Boivin, Michel; Vitaro, Frank; Prusse, Daniel

    2005-01-01

    Using a genetic design of 234 six-year-old twins, this study examined (a) the contribution of genes and environment to social versus physical aggression, and (b) whether the correlation between social and physical aggression can be explained by similar genetic or environmental factors or by a directional link between the phenotypes. For social…

  3. Factors Related to Aggressive and Violent Behavior among Preadolescent African-American Boys.

    ERIC Educational Resources Information Center

    Shields, Nancy; Pierce, Lois

    Drawing on theoretical and empirical studies, this paper hypothesized that attitudes towards the use of violence and the use of aggressive and violent behavior among preadolescent African American males would be affected by verbal aggression in the home, violence observed in the community, family environment, and peer models. Data on aggressive…

  4. Moderating Effects of Autism on Parent Views of Genetic Screening for Aggression

    ERIC Educational Resources Information Center

    May, Michael E.; Brandt, Rachel C.; Bohannan, Joseph K.

    2012-01-01

    Advances in gene-environment interaction research have revealed genes that are associated with aggression. However, little is known about parent perceptions of genetic screening for behavioral symptoms like aggression as opposed to diagnosing disabilities. These perceptions may influence future research endeavors involving genetic linkage studies…

  5. High sulfur isotope fractionation associated with anaerobic oxidation of methane in a low sulfate, iron rich environment

    NASA Astrophysics Data System (ADS)

    Weber, Hannah; Thamdrup, Bo; Habicht, Kirsten

    2016-06-01

    Sulfur isotope signatures provide key information for the study of microbial activity in modern systems and the evolution of the Earth surface redox system. Microbial sulfate reducers shift sulfur isotope distributions by discriminating against heavier isotopes. This discrimination is strain-specific and often suppressed at sulfate concentrations in the lower micromolar range that are typical to freshwater systems and inferred for ancient oceans. Anaerobic oxidation of methane (AOM) is a sulfate-reducing microbial process with a strong impact on global sulfur cycling in modern habitats and potentially in the geological past, but its impact on sulfur isotope signatures is poorly understood, especially in low sulfate environments. We investigated sulfur cycling and 34S fractionation in a low-sulfate freshwater sediment with biogeochemical conditions analogous to Early Earth environments. The zone of highest AOM activity was associated in situ with a zone of strong 34S depletions in the pool of reduced sulfur species, indicating a coupling of sulfate reduction and AOM at sulfate concentrations < 50 µmol L-1. In slurry incubations of AOM-active sediment, the addition of methane stimulated sulfate reduction and induced a bulk sulfur isotope effect of ~29 ‰. Our results imply that sulfur isotope signatures may be strongly impacted by AOM even at sulfate concentrations two orders of magnitude lower than at present oceanic levels. Therefore, we suggest that sulfur isotope fractionation during AOM must be considered when interpreting 34S signatures in modern and ancient environment.

  6. Oxidation and protection of fiberglass-epoxy composite masts for photovoltaic arrays in the low Earth orbital environment

    NASA Technical Reports Server (NTRS)

    Rutledge, Sharon K.; Paulsen, Phillip E.; Brady, Joyce A.; Ciancone, Michael L.

    1988-01-01

    Fiberglass-epoxy composites are considered for use as structural members for the mast of the space station solar array panel. The low Earth orbital environment in which space station is to operate is composed mainly of atomic oxygen, which has been shown to cause erosion of many organic materials and some metals. Ground based testing in a plasma asher was performed to determine the extent of degradation of fiberglass-epoxy composites when exposed to a simulated atomic oxygen environment. During exposure, the epoxy at the surface of the composite was oxidized, exposing individual glass fibers which could easily be removed. Several methods of protecting the composite were evaluated in an atomic oxygen environment and with thermal cycling and flexing. The protection techniques evaluated to date include an aluminum braid covering, an indium-tin eutectic and a silicone based paint. The open aluminum braid offered little protection while the CV-1144 coating offered some initial protection against atomic oxygen, but appears to develop cracks which accelerate degradation when flexed. Coatings such as the In-Sn eutectic may provide adequate protection by containing the glass fibers even though mass loss still occurs.

  7. Paralinear Oxidation of Silicon Nitride in a Water Vapor/Oxygen Environment

    NASA Technical Reports Server (NTRS)

    Fox, Dennis S.; Opila, Elizabeth J.; Nguyen, QuynhGiao; Humphrey, Donald L.; Lewton, Susan M.; Gray, Hugh R. (Technical Monitor)

    2002-01-01

    Three silicon nitride materials were exposed to dry oxygen flowing at 0.44 cm/s at temperatures between 1200 and 1400 C. Reaction kinetics were measured with a continuously recording microbalance. Parabolic kinetics were observed. When the same materials were exposed to a 50% H2O - 50% O2 gas mixture flowing at 4.4 cm/s, all three types exhibited paralinear kinetics. The material is oxidized by water vapor to form solid silica. The protective silica is in turn volatilized by water vapor to form primarily gaseous Si(OH)4. Nonlinear least squares analysis and a paralinear kinetic model were used to determine both parabolic and linear rate constants from the kinetic data. Volatilization of the protective silica scale can result in accelerated consumption of Si3N4. Recession rates under conditions more representative of actual combustors are compared to the furnace data.

  8. Toxicity of lanthanum oxide (La2O3) nanoparticles in aquatic environments.

    PubMed

    Balusamy, Brabu; Taştan, Burcu Ertit; Ergen, Seyda Fikirdesici; Uyar, Tamer; Tekinay, Turgay

    2015-07-01

    This study demonstrates the acute toxicity of lanthanum oxide nanoparticles (La2O3 NP) on two sentinel aquatic species, fresh-water microalgae Chlorella sp. and the crustacean Daphnia magna. The morphology, size and charge of the nanoparticles were systematically studied. The algal growth inhibition assay confirmed absence of toxic effects of La2O3 NP on Chlorella sp., even at higher concentration (1000 mg L(-1)) after 72 h exposure. Similarly, no significant toxic effects were observed on D. magna at concentrations of 250 mg L(-1) or less, and considerable toxic effects were noted in higher concentrations (effective concentration [EC50] 500 mg L(-1); lethal dose [LD50] 1000 mg L(-1)). In addition, attachment of La2O3 NP on aquatic species was demonstrated using microscopy analysis. This study proved to be beneficial in understanding acute toxicity in order to provide environmental protection as part of risk assessment strategies. PMID:26022751

  9. Plutonium release from pressed plutonium oxide fuel pellets in aquatic environments

    SciTech Connect

    Patterson, J.H.; Steinkruger, F.J.; Matlack, G.M.; Heaton, R.C.; Coffelt, K.P.; Herrera, B.

    1983-12-01

    Plutonium oxide pellets (80% /sup 238/Pu, 40 g each) were exposed to fresh water and sea water at two temperatures for 3 y in enclosed glass chambers. The concentrations of plutonium observed in the waters increased linearly with time throughout the experiment. However, the observed release rates were inversely dependent on temperature and salinity, ranging from 160 ..mu..Ci/day for cold fresh water to 1.4 ..mu..Ci/day for warm sea water. The total releases, including the chamber residues, showed similar dependencies. A major portion (typically greater than 50%) of the released plutonium passed through a 0.1-..mu..m filter, with even larger fractions (greater than 80%) for the fresh water systems.

  10. Exoelectrogens Leading to Precise Reduction of Graphene Oxide by Flexibly Switching Their Environment during Respiration.

    PubMed

    Bansal, Prerna; Doshi, Sejal; Panwar, Ajay S; Bahadur, Dhirendra

    2015-09-23

    Reduced graphene oxide (RGO) has been prepared by a simple, cost-effective, and green route. In this work, graphene oxide (GO) has been reduced using Gram-negative facultative anaerobe S. dysenteriae, having exogenic properties of electron transfer via electron shuttling. Apparently, different concentrations of GO were successfully reduced with almost complete mass recovery. An effective role of lipopolysaccharide has been observed while comparing RGO reduced by S. dysenteriae and S. aureus. It was observed that the absence of lipopolysaccharide in Gram-positive S. aureus leads to a disrupted cell wall and that S.aureus could not survive in the presence of GO, leading to poor and inefficient reduction of GO, as shown in our results. However, S. dysenteriae having an outer lipopolysaccharide layer on its cell membrane reduced GO efficiently and the reduction process was extracellular for it. RGO prepared in our work has been characterized by X-ray diffraction, ζ potential, X-ray photoelectron spectroscopy, and Raman spectroscopy techniques, and the results were found to be in good agreement with those of chemically reduced GO. As agglomeration of RGO is the major issue to overcome while chemically reducing GO, we observed that RGO prepared by a bacterial route in our work has ζ potential value of -26.62 mV, good enough to avoid restacking of RGO. The role of exoelectrogens in electron transfer in the extracellular space has been depicted. Toxin released extracellularly during the process paves the way for reduction of GO due to its affinity towards oxygen. PMID:26288348

  11. Biomarkers of aggression in dementia.

    PubMed

    Gotovac, Kristina; Nikolac Perković, Matea; Pivac, Nela; Borovečki, Fran

    2016-08-01

    Dementia is a clinical syndrome defined by progressive global impairment of acquired cognitive abilities. It can be caused by a number of underlying conditions. The most common types of dementia are Alzheimer's disease (AD), frontotemporal dementia (FTD), vascular cognitive impairment (VCI) and dementia with Lewy bodies (DLB). Despite the fact that cognitive impairment is central to the dementia, noncognitive symptoms, most commonly described nowadays as neuropsychiatric symptoms (NPS) exist almost always at certain point of the illness. Aggression as one of the NPS represents danger both for patients and caregivers and the rate of aggression correlates with the loss of independence, cognitive decline and poor outcome. Therefore, biomarkers of aggression in dementia patients would be of a great importance. Studies have shown that different genetic factors, including monoamine signaling and processing, can be associated with various NPS including aggression. There have been significant and multiple neurotransmitter changes identified in the brains of patients with dementia and some of these changes have been involved in the etiology of NPS. Aggression specific changes have also been observed in neuropathological studies. The current consensus is that the best approach for development of such biomarkers may be incorporation of genetics (polymorphisms), neurobiology (neurotransmitters and neuropathology) and neuroimaging techniques. PMID:26952705

  12. Why are small males aggressive?

    PubMed Central

    Morrell, Lesley J; Lindström, Jan; Ruxton, Graeme D

    2005-01-01

    Aggression is ubiquitous in the animal kingdom, whenever the interests of individuals conflict. In contests between animals, the larger opponent is often victorious. However, counter intuitively, an individual that has little chance of winning (generally smaller individuals) sometimes initiates contests. A number of hypotheses have been put forward to explain this behaviour, including the ‘desperado effect’ according to which, the likely losers initiate aggression due to lack of alternative options. An alternative explanation suggested recently is that likely losers attack due to an error in perception: they mistakenly perceive their chances of winning as being greater than they are. We show that explaining the apparently maladaptive aggression initiated by the likely loser can be explained on purely economic grounds, without requiring either the desperado effect or perception errors. Using a game-theoretical model, we show that if smaller individuals can accurately assess their chance of winning, if this chance is less than, but close to, a half, and if resources are scarce (or the contested resource is of relatively low value), they are predicted to be as aggressive as their larger opponents. In addition, when resources are abundant, and small individuals have some chance of winning, they may be more aggressive than their larger opponents, as it may benefit larger individuals to avoid the costs of fighting and seek alternative uncontested resources. PMID:16024387

  13. Performance of Ceramics in Severe Environments

    NASA Technical Reports Server (NTRS)

    Jacobson, Nathan S.; Fox, Dennis S.; Smialek, James L.; Deliacorte, Christopher; Lee, Kang N.

    2005-01-01

    Ceramics are generally stable to higher temperatures than most metals and alloys. Thus the development of high temperature structural ceramics has been an area of active research for many years. While the dream of a ceramic heat engine still faces many challenges, niche markets are developing for these materials at high temperatures. In these applications, ceramics are exposed not only to high temperatures but also aggressive gases and deposits. In this chapter we review the response of ceramic materials to these environments. We discuss corrosion mechanisms, the relative importance of a particular corrodent, and, where available, corrosion rates. Most of the available corrosion information is on silicon carbide (SIC) and silicon nitride (Si3N4) monolithic ceramics. These materials form a stable film of silica (SO2) in an oxidizing environment. We begin with a discussion of oxidation of these materials and proceed to the effects of other corrodents such as water vapor and salt deposits. We also discuss oxidation and corrosion of other ceramics: precurser derived ceramics, ceramic matrix composites (CMCs), ceramics which form oxide scales other than silica, and oxide ceramics. Many of the corrosion issues discussed can be mitigated with refractory oxide coatings and we discuss the current status of this active area of research. Ultimately, the concern of corrosion is loss of load bearing capability. We discuss the effects of corrosive environments on the strength of ceramics, both monolithic and composite. We conclude with a discussion of high temperature wear of ceramics, another important form of degradation at high temperatures.

  14. Impact of Air Filter Material on Metal Oxide Semiconductor (MOS) Device Characteristics in HF Vapor Environment

    NASA Astrophysics Data System (ADS)

    Hsiao, Chih-Wen; Lou, Jen-Chung; Yeh, Ching-Fa; Hsieh, Chih-Ming; Lin, Shiuan-Jeng; Kusumi, Toshio

    2004-05-01

    Airborne molecular contamination (AMC) is becoming increasingly important as devices are scaled down to the nanometer generation. Optimum ultra low penetration air (ULPA) filter technology can eliminate AMC. In a cleanroom, however, the acid vapor generated from the cleaning process may degrade the ULPA filter, releasing AMC to the air and the surface of wafers, degrading the electrical characteristics of devices. This work proposes the new PTFE ULPA filter, which is resistant to acid vapor corrosion, to solve this problem. Experimental results demonstrate that the PTFE ULPA filter can effectively eliminate the AMC and provide a very clean cleanroom environment.

  15. The benefits of aggressive traits: a study with current and former street children in Burundi.

    PubMed

    Crombach, Anselm; Elbert, Thomas

    2014-06-01

    Aggressive behavior in children and youths is commonly associated with exposure to violence and maltreatment. Consequently, aggressive behavior has often been explained as a form of reactive behavior in response to violence-inflicted mental suffering. However, perpetrating violence can become appealing, fascinating and exciting, i.e., may acquire appetitive, self-rewarding aspects. We postulated that this appetitive form of aggression reduces the vulnerability for developing Posttraumatic Stress Disorder (PTSD) in insecure and violent environments. Furthermore we investigated the extent to which reactive aggression and appetitive aggression account for recent violent behavior in children and youths. We conducted semi-structured interviews in a sample of 112 children and youths (Mage=15.9 years) recruited from the streets, families and a residential center for vulnerable children in Burundi. We investigated the cumulative exposure to traumatic events and to domestic and community violence, assessed the recently committed offenses, the severity of PTSD symptoms, and the potential for reactive and appetitive aggression. Reactive aggression was positively related to PTSD, whilst appetitive aggression was negatively related to PTSD. Children higher in appetitive aggression were also more likely to display violent behavior. These results suggest that an appetitive perception of violence may be an useful adaption to insecure and violent living conditions reducing the vulnerability of children for trauma-related mental disorders. However, positive feelings experienced through violent or cruel behavior are also an important risk factor for ongoing aggressive behavior and therefore need to be considered in prevention strategies. PMID:24411982

  16. Exposure to aggressive behaviour and burnout in direct support providers: The role of positive work factors.

    PubMed

    Hensel, Jennifer M; Lunsky, Yona; Dewa, Carolyn S

    2014-11-11

    Many direct support providers (DSPs) are exposed to aggressive behaviour in their work supporting adults with developmental disabilities service recipients. This is a work environment factor that has been linked to job burnout. The objective of this study was to examine the impact of positive work factors on emotional exhaustion (EE) among DSPs who are exposed to aggressive behaviour. Survey responses from 671 DSPs who were working in community service settings for adults with developmental disabilities, and were exposed to aggressive behaviour at least monthly were examined. Hierarchical linear regression examined the direct contribution and moderating role of positive work factors (self-efficacy for dealing with aggression and work contributions) on EE measured with the Maslach Burnout Inventory-Human Services Survey, after controlling for demographics, occupational variables, exposure to aggression and negative emotional reactions to aggression. Results showed that younger age, more experience, more depression/anger emotions in response to aggression, lower self-efficacy and low positive work contributions were significantly associated with EE. Positive work motivation was a moderator of exposure to aggression and EE. When work motivations were low, DSPs were more negatively affected by higher exposure to aggression. These findings suggest that in addition to addressing the negative emotional reactions to the aggressive behaviour encountered at work, it is also important to foster positive work factors which may be protective against EE. PMID:25462500

  17. The Architecture of Iron Microbial Mats Reflects the Adaptation of Chemolithotrophic Iron Oxidation in Freshwater and Marine Environments

    PubMed Central

    Chan, Clara S.; McAllister, Sean M.; Leavitt, Anna H.; Glazer, Brian T.; Krepski, Sean T.; Emerson, David

    2016-01-01

    Microbes form mats with architectures that promote efficient metabolism within a particular physicochemical environment, thus studying mat structure helps us understand ecophysiology. Despite much research on chemolithotrophic Fe-oxidizing bacteria, Fe mat architecture has not been visualized because these delicate structures are easily disrupted. There are striking similarities between the biominerals that comprise freshwater and marine Fe mats, made by Beta- and Zetaproteobacteria, respectively. If these biominerals are assembled into mat structures with similar functional morphology, this would suggest that mat architecture is adapted to serve roles specific to Fe oxidation. To evaluate this, we combined light, confocal, and scanning electron microscopy of intact Fe microbial mats with experiments on sheath formation in culture, in order to understand mat developmental history and subsequently evaluate the connection between Fe oxidation and mat morphology. We sampled a freshwater sheath mat from Maine and marine stalk and sheath mats from Loihi Seamount hydrothermal vents, Hawaii. Mat morphology correlated to niche: stalks formed in steeper O2 gradients while sheaths were associated with low to undetectable O2 gradients. Fe-biomineralized filaments, twisted stalks or hollow sheaths, formed the highly porous framework of each mat. The mat-formers are keystone species, with nascent marine stalk-rich mats comprised of novel and uncommon Zetaproteobacteria. For all mats, filaments were locally highly parallel with similar morphologies, indicating that cells were synchronously tracking a chemical or physical cue. In the freshwater mat, cells inhabited sheath ends at the growing edge of the mat. Correspondingly, time lapse culture imaging showed that sheaths are made like stalks, with cells rapidly leaving behind an Fe oxide filament. The distinctive architecture common to all observed Fe mats appears to serve specific functions related to chemolithotrophic Fe

  18. The Architecture of Iron Microbial Mats Reflects the Adaptation of Chemolithotrophic Iron Oxidation in Freshwater and Marine Environments.

    PubMed

    Chan, Clara S; McAllister, Sean M; Leavitt, Anna H; Glazer, Brian T; Krepski, Sean T; Emerson, David

    2016-01-01

    Microbes form mats with architectures that promote efficient metabolism within a particular physicochemical environment, thus studying mat structure helps us understand ecophysiology. Despite much research on chemolithotrophic Fe-oxidizing bacteria, Fe mat architecture has not been visualized because these delicate structures are easily disrupted. There are striking similarities between the biominerals that comprise freshwater and marine Fe mats, made by Beta- and Zetaproteobacteria, respectively. If these biominerals are assembled into mat structures with similar functional morphology, this would suggest that mat architecture is adapted to serve roles specific to Fe oxidation. To evaluate this, we combined light, confocal, and scanning electron microscopy of intact Fe microbial mats with experiments on sheath formation in culture, in order to understand mat developmental history and subsequently evaluate the connection between Fe oxidation and mat morphology. We sampled a freshwater sheath mat from Maine and marine stalk and sheath mats from Loihi Seamount hydrothermal vents, Hawaii. Mat morphology correlated to niche: stalks formed in steeper O2 gradients while sheaths were associated with low to undetectable O2 gradients. Fe-biomineralized filaments, twisted stalks or hollow sheaths, formed the highly porous framework of each mat. The mat-formers are keystone species, with nascent marine stalk-rich mats comprised of novel and uncommon Zetaproteobacteria. For all mats, filaments were locally highly parallel with similar morphologies, indicating that cells were synchronously tracking a chemical or physical cue. In the freshwater mat, cells inhabited sheath ends at the growing edge of the mat. Correspondingly, time lapse culture imaging showed that sheaths are made like stalks, with cells rapidly leaving behind an Fe oxide filament. The distinctive architecture common to all observed Fe mats appears to serve specific functions related to chemolithotrophic Fe

  19. Developmental Cascades of Peer Rejection, Social Information Processing Biases, and Aggression During Middle Childhood

    PubMed Central

    Lansford, Jennifer E.; Malone, Patrick S.; Dodge, Kenneth A.; Pettit, Gregory S.; Bates, John E.

    2010-01-01

    This study tested a developmental cascade model of peer rejection, social information processing (SIP), and aggression using data from 585 children assessed at 12 time points from kindergarten through grade 3. Peer rejection had direct effects on subsequent SIP problems and aggression. SIP had direct effects on subsequent peer rejection and aggression. Aggression had direct effects on subsequent peer rejection. Each construct also had indirect effects on each of the other constructs. These findings advance the literature beyond a simple mediation approach by demonstrating how each construct effects changes in the others in a snowballing cycle over time. The progressions of SIP problems and aggression cascaded through lower liking, and both better SIP skills and lower aggression facilitated the progress of social preference. Findings are discussed in terms of the dynamic, developmental relations among social environments, cognitions, and behavioral adjustment. PMID:20576181

  20. Accuracy in Judgments of Aggressiveness

    PubMed Central

    Kenny, David A.; West, Tessa V.; Cillessen, Antonius H. N.; Coie, John D.; Dodge, Kenneth A.; Hubbard, Julie A.; Schwartz, David

    2009-01-01

    Perceivers are both accurate and biased in their understanding of others. Past research has distinguished between three types of accuracy: generalized accuracy, a perceiver’s accuracy about how a target interacts with others in general; perceiver accuracy, a perceiver’s view of others corresponding with how the perceiver is treated by others in general; and dyadic accuracy, a perceiver’s accuracy about a target when interacting with that target. Researchers have proposed that there should be more dyadic than other forms of accuracy among well-acquainted individuals because of the pragmatic utility of forecasting the behavior of interaction partners. We examined behavioral aggression among well-acquainted peers. A total of 116 9-year-old boys rated how aggressive their classmates were toward other classmates. Subsequently, 11 groups of 6 boys each interacted in play groups, during which observations of aggression were made. Analyses indicated strong generalized accuracy yet little dyadic and perceiver accuracy. PMID:17575243

  1. Electrical Stability of a Novel Refractory Sealing Glass in a Dual Environment for Solid Oxide Fuel Cell Applications

    SciTech Connect

    Chou, Y. S.; Stevenson, Jeffry W.; Meinhardt, Kerry D.

    2010-03-01

    A novel refractory alkaline-earth silicate (Sr-Ca-Y-B-Si) sealing glass was developed for solid oxide fuel cell (SOFC) applications. The glass was sealed between two metallic interconnect plates and tested for electrical stability at elevated temperatures and duel environments under DC loading. The isothermal aging results showed very stable electrical resistivity with values 5-9 orders of magnititudes higher than typical SOFC function materials at 850 degrees C for ~700 hr. For comparison, the state-of-the-art sealing glass (G18, Ba-Ca-Al-B-Si) was also evaluated in a similar condition and showed less stable in accelerated tests at 830 degrees C for ~100 hr. Interfacial microstruicture was characterized and possible reactions were discussed.

  2. Oxidation and protection of fiberglass-epoxy composite masts for photovoltaic arrays in the low earth orbital environment

    NASA Technical Reports Server (NTRS)

    Rutledge, Sharon K.; Ciancone, Michael L.; Paulsen, Phillip E.; Brady, Joyce A.

    1988-01-01

    The extent of degradation of fiberglass-epoxy composite masts of the Space Station solar array panel, when these are exposed to atomic oxygen environment of the low-earth orbit, was investigated in ground testing of fiberglass-epoxy composites in an RF plasma asher. In addition, several methods of protecting the composite structures were evaluated, including an aluminum braid covering, an In-Sn eutectic, and a silicone based paint. It was found that, during exposure, the epoxy at the surface of the composite was oxidized, exposing individual glass fibers which could easily be removed. The results of mass measurements and SEM examination carried out after thermal cycling and flexing of exposed composite samples indicated that coatings such as In-Sn eutectic may provide adequate protection by containing the glass fibers, even though mass loss still occurs.

  3. Microbial Oxidation of Arsenite in a Subarctic Environment: Diversity of Arsenite Oxidase Genes and Identification of a Psychrotolerant Arsenite Oxidiser

    SciTech Connect

    Osborne, T.; Jamieson, H; Hudson-Edwards, K; Nordstrom, D; Walker, S; Ward, S; Santini, J

    2010-01-01

    Arsenic is toxic to most living cells. The two soluble inorganic forms of arsenic are arsenite (+3) and arsenate (+5), with arsenite the more toxic. Prokaryotic metabolism of arsenic has been reported in both thermal and moderate environments and has been shown to be involved in the redox cycling of arsenic. No arsenic metabolism (either dissimilatory arsenate reduction or arsenite oxidation) has ever been reported in cold environments (i.e. < 10 C). Our study site is located 512 kilometres south of the Arctic Circle in the Northwest Territories, Canada in an inactive gold mine which contains mine waste water in excess of 50 mM arsenic. Several thousand tonnes of arsenic trioxide dust are stored in underground chambers and microbial biofilms grow on the chamber walls below seepage points rich in arsenite-containing solutions. We compared the arsenite oxidisers in two subsamples (which differed in arsenite concentration) collected from one biofilm. 'Species' (sequence) richness did not differ between subsamples, but the relative importance of the three identifiable clades did. An arsenite-oxidizing bacterium (designated GM1) was isolated, and was shown to oxidise arsenite in the early exponential growth phase and to grow at a broad range of temperatures (4-25 C). Its arsenite oxidase was constitutively expressed and functioned over a broad temperature range. The diversity of arsenite oxidisers does not significantly differ from two subsamples of a microbial biofilm that vary in arsenite concentrations. GM1 is the first psychrotolerant arsenite oxidiser to be isolated with the ability to grow below 10 C. This ability to grow at low temperatures could be harnessed for arsenic bioremediation in moderate to cold climates.

  4. Neutrophilic Iron-Oxidizing “Zetaproteobacteria” and Mild Steel Corrosion in Nearshore Marine Environments ▿ †

    PubMed Central

    McBeth, Joyce M.; Little, Brenda J.; Ray, Richard I.; Farrar, Katherine M.; Emerson, David

    2011-01-01

    Microbiologically influenced corrosion (MIC) of mild steel in seawater is an expensive and enduring problem. Little attention has been paid to the role of neutrophilic, lithotrophic, iron-oxidizing bacteria (FeOB) in MIC. The goal of this study was to determine if marine FeOB related to Mariprofundus are involved in this process. To examine this, field incubations and laboratory microcosm experiments were conducted. Mild steel samples incubated in nearshore environments were colonized by marine FeOB, as evidenced by the presence of helical iron-encrusted stalks diagnostic of the FeOB Mariprofundus ferrooxydans, a member of the candidate class “Zetaproteobacteria.” Furthermore, Mariprofundus-like cells were enriched from MIC biofilms. The presence of Zetaproteobacteria was confirmed using a Zetaproteobacteria-specific small-subunit (SSU) rRNA gene primer set to amplify sequences related to M. ferrooxydans from both enrichments and in situ samples of MIC biofilms. Temporal in situ incubation studies showed a qualitative increase in stalk distribution on mild steel, suggesting progressive colonization by stalk-forming FeOB. We also isolated a novel FeOB, designated Mariprofundus sp. strain GSB2, from an iron oxide mat in a salt marsh. Strain GSB2 enhanced uniform corrosion from mild steel in laboratory microcosm experiments conducted over 4 days. Iron concentrations (including precipitates) in the medium were used as a measure of corrosion. The corrosion in biotic samples (7.4 ± 0.1 mM) was significantly higher than that in abiotic controls (5.0 ± 0.1 mM). These results have important implications for the role of FeOB in corrosion of steel in nearshore and estuarine environments. In addition, this work shows that the global distribution of Zetaproteobacteria is far greater than previously thought. PMID:21131509

  5. Predictive calculations of volatilities of metals and oxides in steam-containing environments

    SciTech Connect

    Krikorian, O.H.

    1981-08-10

    Predictive methods are developed for estimating the bond energies and free energy functions of volatile species having the general formula MO/sub x/ (OH)/sub y/, in order to shed some light on the mechanisms and extent of steam accelerated volatilization processes. A specific example of applying the data is illustrated for the case of a proposed underground radioactive waste disposal process, where oxides of radionuclides are allowed to equilibrate with 100 atm steam and 10/sup -2/ atm oxygen at 1000 to 2000K. Vapor species found to have high volatilities include Cs/sub 2/(OH)/sub 2/, CsOH, AmO/sub 2/(OH)/sub 2/, AmO(OH)/sub 3/, UO/sub 2/(OH)/sub 2/, NbO(OH)/sub 3/, PuO/sub 2/(OH)/sub 2/, CeO(OH)/sub 2/, Ba(OH)/sub 2/, and Eu(OH)/sub 3/. Thermodynamic data are tabulated for all possible monomeric species for this specific example.

  6. Research to Significantly Enhance Composites Survivability at 550 F in Oxidative Environments

    NASA Technical Reports Server (NTRS)

    Meador, Michael A. (Technical Monitor); Guinn, L.; Tewoldeberhan, A.; Inkurnsah, M.; Makori, F.; Carty, A.; Carson, L.

    2003-01-01

    Methylene dianiline (MDA) and its derivatives have been used in the synthesis of polyimides to yield polymers with characteristic low-density, high tensile strength, improved solubility in organic solvents, low-melt viscosities and high thermal stability (greater than 550 F) in air. Polyimides with such properties are desirable for use in aerospace systems, e.g., jet engines, airframe, missiles, and rockets where weight is critical. Recent research at Prairie View A&M University is focused on developing monomers to generate polyimides with enhanced performance over that of NASA s PMR-15. The objective of this work is to synthesize three ring aromatic diamines which are non-toxic and when reacted with the appropriate dianhydrides will yield polyimides with lower viscosity, improve processability, good retention of mechanical properties, and oxidative stability at high environmental temperatures. Modifications of the three ring aromatic diamines include replacing the methylene linkages with aromatic ethers by nucleophilic aromatic substitution reactions and incorporating mono- and di-substituents to the center aromatic ring. An update of current reactions involved in synthesis efforts to generate three ring aromatic monomers for polyimides with methylene, carbonyl, and ether linkages separating the aromatic moieties will be displayed.

  7. Long-term exposure of pressed plutonium oxide heat sources to aquatic environments

    SciTech Connect

    Heaton, R.C.; Patterson, J.H.; Kosiewicz, S.T.; Matlack, G.M.; Steinkruger, F.J.; Nelson, G.B.; Vanderborgh, N.E.; Coffelt, K.P.; Herrera, B.

    1984-11-01

    Plutonium-238 oxide fuel pellets were exposed to water for 2.5 to 6.4 yr, and the concentration of plutonium in the water was monitored. Water composition and temperature were found to be important factors in determining the rate of plutonium release into the water. Typical release rates ranged from 10 to 40 ng/m/sup 2//s in cold fresh water and from 0.3 to 11 ng/m/sup 2//s in cold sea water. Release rates in sea water varied over time and sometimes were erratic. The plutonium release per unit area did not depend on the size of the PuO/sub 2/ source. The released plutonium was in an extremely fine form, able to pass through 10,000 molecular weight cutoff filters. Apparent differences in the fuel pellet surfaces after exposure suggest that plutonium release is controlled by physical and chemical processes occurring at the solid-liquid interface. Release mechanisms and their implications are discussed.

  8. Research to Significantly Enhance Composite Survivability at 550 F in Oxidative Environments

    NASA Technical Reports Server (NTRS)

    Byrd, Jim; Guinn, LaToya; Tilley, Kendra; Carson, Laura; Carty, Antoine; Meador, Michael (Technical Monitor)

    2001-01-01

    Prairie View A&M University using the NASA FAR grant has embarked on several paths to accomplish the initial goals of: (1) synthesizing three ring aromatic diamines to be used as monomers in the synthesis of polyamide resins; and (2) study hydrothermal aging behaviors and glass transition changes of composites synthesized at NASA Glenn Research Center. In establishing the synthesis of the three ring aromatic diamine, it has become necessary to conduct preliminary synthesis to include the nitration of diphenylmethane. The concentration and temperature were altered to assess the effect of purity of isomeric product distribution in such electrophilic aromatic substitution reaction. Products were analyzed using H and C-NMR, Thin Layer Chromatography, High Pressure Liquid Chromatography and GC-Mass Spectrometry (in progress). Results indicate that by varying the concentration of the reaction, a mixture of products can be obtained. Other electrophilic aromatic substitution reactions are also in progress such as Friedel-Craft acylation reaction using diphenylmethane with 4-nitrobenzoyl chloride to afford other diamine products. Furthermore, PVAMU has nearly completed the hydrothermal studies to assess the oxidative stability of DSP443B and DSP442A panels formulated at NASA Glenn Research Center.

  9. A laboratory investigation of interactions between denitrifying anaerobic methane oxidation (DAMO) and anammox processes in anoxic environments

    NASA Astrophysics Data System (ADS)

    Hu, Shihu; Zeng, Raymond J.; Haroon, Mohamed F.; Keller, Jurg; Lant, Paul A.; Tyson, Gene W.; Yuan, Zhiguo

    2015-03-01

    This study investigates interactions between recently identified denitrifying anaerobic methane oxidation (DAMO) and anaerobic ammonium oxidation (anammox) processes in controlled anoxic laboratory reactors. Two reactors were seeded with the same inocula containing DAMO organisms Candidatus Methanoperedens nitroreducens and Candidatus Methylomirabilis oxyfera, and anammox organism Candidatus Kuenenia stuttgartiensis. Both were fed with ammonium and methane, but one was also fed with nitrate and the other with nitrite, providing anoxic environments with different electron acceptors. After steady state reached in several months, the DAMO process became solely/primarily responsible for nitrate reduction while the anammox process became solely responsible for nitrite reduction in both reactors. 16S rRNA gene amplicon sequencing showed that the nitrate-driven DAMO organism M. nitroreducens dominated both the nitrate-fed (~70%) and the nitrite-fed (~26%) reactors, while the nitrite-driven DAMO organism M. oxyfera disappeared in both communities. The elimination of M. oxyfera from both reactors was likely the results of this organism being outcompeted by anammox bacteria for nitrite. K. stuttgartiensis was detected at relatively low levels (1-3%) in both reactors.

  10. A laboratory investigation of interactions between denitrifying anaerobic methane oxidation (DAMO) and anammox processes in anoxic environments

    PubMed Central

    Hu, Shihu; Zeng, Raymond J.; Haroon, Mohamed F.; Keller, Jurg; Lant, Paul A.; Tyson, Gene W.; Yuan, Zhiguo

    2015-01-01

    This study investigates interactions between recently identified denitrifying anaerobic methane oxidation (DAMO) and anaerobic ammonium oxidation (anammox) processes in controlled anoxic laboratory reactors. Two reactors were seeded with the same inocula containing DAMO organisms Candidatus Methanoperedens nitroreducens and Candidatus Methylomirabilis oxyfera, and anammox organism Candidatus Kuenenia stuttgartiensis. Both were fed with ammonium and methane, but one was also fed with nitrate and the other with nitrite, providing anoxic environments with different electron acceptors. After steady state reached in several months, the DAMO process became solely/primarily responsible for nitrate reduction while the anammox process became solely responsible for nitrite reduction in both reactors. 16S rRNA gene amplicon sequencing showed that the nitrate-driven DAMO organism M. nitroreducens dominated both the nitrate-fed (~70%) and the nitrite-fed (~26%) reactors, while the nitrite-driven DAMO organism M. oxyfera disappeared in both communities. The elimination of M. oxyfera from both reactors was likely the results of this organism being outcompeted by anammox bacteria for nitrite. K. stuttgartiensis was detected at relatively low levels (1–3%) in both reactors. PMID:25732131

  11. The electroluminescence mechanism of Er3+ in different silicon oxide and silicon nitride environments

    NASA Astrophysics Data System (ADS)

    Rebohle, L.; Berencén, Y.; Wutzler, R.; Braun, M.; Hiller, D.; Ramírez, J. M.; Garrido, B.; Helm, M.; Skorupa, W.

    2014-09-01

    Rare earth doped metal-oxide-semiconductor (MOS) structures are of great interest for Si-based light emission. However, several physical limitations make it difficult to achieve the performance of light emitters based on compound semiconductors. To address this point, in this work the electroluminescence (EL) excitation and quenching mechanism of Er-implanted MOS structures with different designs of the dielectric stack are investigated. The devices usually consist of an injection layer made of SiO2 and an Er-implanted layer made of SiO2, Si-rich SiO2, silicon nitride, or Si-rich silicon nitride. All structures implanted with Er show intense EL around 1540 nm with EL power efficiencies in the order of 2 × 10-3 (for SiO2:Er) or 2 × 10-4 (all other matrices) for lower current densities. The EL is excited by the impact of hot electrons with an excitation cross section in the range of 0.5-1.5 × 10-15 cm-2. Whereas the fraction of potentially excitable Er ions in SiO2 can reach values up to 50%, five times lower values were observed for other matrices. The decrease of the EL decay time for devices with Si-rich SiO2 or Si nitride compared to SiO2 as host matrix implies an increase of the number of defects adding additional non-radiative de-excitation paths for Er3+. For all investigated devices, EL quenching cross sections in the 10-20 cm2 range and charge-to-breakdown values in the range of 1-10 C cm-2 were measured. For the present design with a SiO2 acceleration layer, thickness reduction and the use of different host matrices did not improve the EL power efficiency or the operation lifetime, but strongly lowered the operation voltage needed to achieve intense EL.

  12. 3rd hand smoking; heterogeneous oxidation of nicotine and secondary aerosol formation in the indoor environment

    NASA Astrophysics Data System (ADS)

    Petrick, Lauren; Dubowski, Yael

    2010-05-01

    Tobacco smoking is well known as a significant source of primary indoor air pollutants. However, only recently has it been recognized that the impact of Tobacco smoking may continue even after the cigarette has been extinguished (i.e., third hand smoke) due to the effect of indoor surfaces. These surfaces may affect the fate of tobacco smoke in the form of secondary reactions and pollutants, including secondary organic aerosol (SOA) formation. Fourier Transform Infrared spectrometry with Attenuated Total Reflection (FTIR-ATR) in tandem with a Scanning Mobility Particle Sizing (SMPS) system was used to monitor the ozonation of cellulose sorbed nicotine and resulting SOA formation. SOA formation began at onset of ozone introduction ([O3] = 60 ± 5 ppb) with a size distribution of dp ≤ 25 nm, and was determined to be a result of heterogeneous reaction (opposed to homogeneous). SOA yield from reacted surface nicotine was on the order of 10 %. Simultaneous to SOA monitoring, FTIR-ATR spectra showed surface changes in the nicotine film as the reaction progressed, revealing a pseudo first-order surface reaction rate of 0.0026 ± 0.0008 min-1. Identified surface oxidation products included: cotinine, myosmine, methylnicotinamide and nicotyrine. Surface reaction rate was found to be partially inhibited at high relative humidity. Given the toxicity of some of the identified products (e.g., cotinine has shown potential mutagenicity and teratogenicity) and that small particles may contribute to adverse health effects, the present study indicates that exposure to 3rd hand smoke ozonation products may pose additional health risks.

  13. Development and application of a novel immunoassay for measuring oxidative DNA damage in the environment.

    PubMed

    Mitchell, David L; Meador, Jarah; Paniker, Laxmi; Gasparutto, Didier; Jeffrey, Wade H; Cadet, Jean

    2002-03-01

    We developed a facile, cost-effective competitive binding assay for the analysis of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) in DNA, using a polyclonal rabbit antiserum raised against an 8-oxodGuo hapten coupled to bovine serum albumin and radiolabeled synthetic ligand containing multiple 8-oxodGuo residues. This radioimmunoassay (RIA) displays a high affinity for 8-oxodGuo in DNA, with a detection limit of approximately 1 adduct in 10(5) bases of DNA. 8-oxodGuo standards for RIA were quantified by high-performance liquid chromatography and electrochemical detection in DNA diluted in methylene blue and exposed to visible light. As an initial application we quantified 8-oxodGuo in dosimeters deployed at increasing depths in the Southern Ocean during the austral spring of the 1998 field season or at the surface at Palmer Station, Antarctica, throughout the 1999 field season. Cyclobutane pyrimidine dimers (CPD) were quantified using an established RIA. We found that the frequency of both photoproducts decreased with depth. However, CPD induction was attenuated at a faster rate than 8-oxodGuo, correlating with the differential attenuation of solar ultraviolet wavelengths in the water column. CPD induction was closely related with ultraviolet-B radiation (UVB) attenuation, whereas the lower attenuation of 8-oxodGuo suggests that oxidative damage is more closely related to ultraviolet-A radiation (UVA) irradiance. The ratio of 8-oxodGuo: CPD was also found to covary with changes in stratospheric ozone concentrations at Palmer Station. These data demonstrate the usefulness of these assays for environmental photobiology and the potential for their use in studying the relative impacts of UVB versus UVA, including ozone depletion events. PMID:11950091

  14. Effect of Sputtering Gas environments on the Properties of Aluminum-doped Zinc Oxide Thin Films for Photovoltaic Application

    SciTech Connect

    Chauhan, Ram Narayan; Kumar, Jitendra; Singh, C.; Anand, R. S.

    2011-10-20

    Aluminum-doped zinc oxide thin films have been deposited on glass substrates by R.F. sputtering using ZnO(98%)-Al{sub 2}O{sub 3}(2%) target in different sputtering gaseous environments, viz., Ar, Ar/O{sub 2} and Ar/N{sub 2}+H{sub 2} at 80 deg. C. These films have been studied with regard to phase, microstructure, optical absorption and sheet resistance for application in photovoltaic devices as transparent conducting electrodes. The properties of the films are shown to strongly depend on the sputtering gas(es). The films exhibit a wurtzite-type hexagonal structure with the (00.2) preferred orientation, the c-axis perpendicular to the substrate. The intensity of 00.2 diffraction peak and the average crystallite size remain almost the same when the films are prepared under pure Ar or Ar/O{sub 2} environment. However the average crystallite size increases while electrical resistance decreases with introduction of nitrogen and hydrogen in comparison to oxygen in argon. Nevertheless, the optimum value of optical transmittance and sheet resistance of the films deposited in pure argon are found to be 85-96% in the wavelength range 400-800 nm and 65 {Omega}/{open_square}, respectively.

  15. Fate of engineered cerium oxide nanoparticles in an aquatic environment and their toxicity toward 14 ciliated protist species.

    PubMed

    Zhang, Wei; Pu, Zhichao; Du, Songyan; Chen, Yongsheng; Jiang, Lin

    2016-05-01

    The potential environmental impacts of engineered cerium oxide nanoparticles (CeO2 NPs) on aquatic organisms have remained largely unknown. Therefore, the laboratory study featured herein was performed to determine the fate of CeO2 NPs in an aquatic environment and their toxicity towards 14 different ciliated protist species at a specified population level. An investigation of 48 h aggregation kinetics in the Dryl's solution showed the CeO2 NPs to be relatively stable. The pH values in three test medium were too far away from PZC, which explained the stability of CeO2 NPs. CeO2 NPs generally elicited more toxicity with increasing NP concentration, following certain dose-response relationships. Nano-CeO2 resulted in greater toxicity in a particle state than when added as bulk material. LC50 values showed a negative correlation with the surface-to-volume ratio for these protists, suggesting that surface adsorption of CeO2 NPs might contribute to the observed toxicity. Additionally, acute toxic responses of 14 ciliated protist species to CeO2 NPs were not significantly phylogenetically conserved. The results of these observations provide a better insight into the potential risks of CeO2 NPs in an aquatic environment. PMID:26986089

  16. Oxidative alteration of spent fuel in a silica-rich environment: SEM/AEM investigation and geochemical modeling

    SciTech Connect

    WANG,YIFENG; XU,HUIFANG

    2000-03-14

    Correctly identifying the possible alteration products and accurately predicting their occurrence in a repository-relevant environment are the key for the source-term calculation in a repository performance assessment. Uraninite in uranium deposits has long been used as a natural analog to spent fuel in a repository because of their chemical and structural similarity. In this paper, a SEM/AEM investigation has been conducted on a partially alternated uraninite sample from a uranium ore deposit of Shinkolobwe of Congo. The mineral formation sequences were identified: uraninite {yields} uranyl hydrates {yields} uranyl silicates {yields} Ca-uranyl silicates or uraninite {yields} uranyl silicates {yields} Ca-uranyl silicates. Reaction-path calculations were conducted for the oxidative dissolution of spent fuel in a representative Yucca Mountain groundwater. The predicted sequence is in general consistent with the SEM observations. The calculations also show that uranium carbonate minerals are unlikely to become major solubility-controlling mineral phases in a Yucca Mountain environment. Some discrepancies between model predictions and field observations are observed. Those discrepancies may result from poorly constrained thermodynamic data for uranyl silicate minerals.

  17. In situ characterization of green rust in the presence of arsenate and phosphate in simulated oxidized and reduced environments.

    NASA Astrophysics Data System (ADS)

    Root, R. A.; O'Day, P. A.

    2008-12-01

    Nano- to micron-scale particles of mixed-valent iron hydroxide, specifically green rust (GR [FeII6- x(OH)y FeIIIx(OH)12-y]x+[Anionx- + H2O]x-), have been identified and studied as corrosion products of steel, and recently rediscovered in hydromorphic soils and sediments. Green rusts are intermediate phases produced by biotic and abiotic reductive dissolution of ferric oxyhydroxides, or by oxidation of dissolved ferrous iron. Adsorbed oxyanions can stabilize GR phases and inhibit the formation of thermodynamically favored iron phases such as magnetite or lepidocrocite in subsurface environments. This study used synchrotron XRD to characterize iron (hydr)oxide minerals precipitated from solution and subsequent aging products under different environmental conditions of pH and Eh. Here we show the in situ abiotic development of green rust and its stabilization by the addition of adsorbed oxyanions or alternatively, subsequent rapid transformation to magnetite or lepidocrocite in the absence of added anions. A closed batch reactor with an in-line capillary was used to expose the reaction products to continuous synchrotron radiation. Laue patterns were collected at time intervals of 3-5 minutes and used to detect the formation of crystalline iron (hydr)oxide minerals that precipitate as a function time and chemical perturbations to the system, i.e. changing the pH, redox potential, ratio of Fe2+ to OH- , and addition of an oxyanion, arsenate or phosphate. The reactions were monitored by observing the development of diagnostic green rust XRD d-spacing peak at 10.9 Å (300), the 3.29 Å (210) d- spacing for lepidocrocite, and the 2.53 Å (100) d-spacing for magnetite, with continuous in-line measurement of pH and ORP. We found that green rust was stabilized by the adsorption of arsenate and phosphate. In the presence of arsenate or phosphate at pH =7, green rust transformed to lepidocrocite after several hours when anoxic controls were removed. When pH and Eh were constant

  18. Aggression and Violence in Sport: Moving Beyond the Debate

    PubMed Central

    Sacks, David N.; Petscher, Yaacov; Stanley, Christopher T.; Tenenbaum, Gershon

    2015-01-01

    This paper is the latest in a series of articles published in The Sport Psychologist in recent years on aggression and violence in sport (Kerr, 1999, 2002; Tenenbaum, Sacks, Miller, Golden, & Doolin, 2000; Tenenbaum, Stewart, Singer, & Duda, 1997). While these respective articles have presented dissenting views on the nature and prevention of aggression and violence in sport, the present paper proposes that much of the apparent disagreement is semantic in nature. Thus, this paper begins by clarifying some definitional issues before specifying both areas of agreement and continued dissention among recent authors. Major emphases in this paper include the importance of adopting preventative rather than reactive measures to reduce the dangers associated with aggression and violence in sport, as well as the manner in which adult sport norms affect youth sport environments. In addition, several broader issues, which have emerged from these recent published debates, are presented for future consideration. PMID:26855638

  19. Relative Humidity and the Susceptibility of Austenitic Stainless Steel to Stress Corrosion Cracking in an impure Plutonium Oxide Environment

    SciTech Connect

    Zapp, P.; Duffey, J.; Lam, P.; Dunn, K.

    2010-05-05

    Laboratory tests to investigate the corrosivity of moist plutonium oxide/chloride salt mixtures on 304L and 316L stainless steel coupons showed that corrosion occurred in selected samples. The tests exposed flat coupons for pitting evaluation and 'teardrop' stressed coupons for stress corrosion cracking (SCC) evaluation at room temperature to various mixtures of PuO{sub 2} and chloride-bearing salts for periods up to 500 days. The exposures were conducted in sealed containers in which the oxide-salt mixtures were loaded with about 0.6 wt % water from a humidified helium atmosphere. Observations of corrosion ranged from superficial staining to pitting and SCC. The extent of corrosion depended on the total salt concentration, the composition of the salt and the moisture present in the test environment. The most significant corrosion was found in coupons that were exposed to 98 wt % PuO{sub 2}, 2 wt % chloride salt mixtures that contained calcium chloride and 0.6 wt% water. SCC was observed in two 304L stainless steel teardrop coupons exposed in solid contact to a mixture of 98 wt % PuO{sub 2}, 0.9 wt % NaCl, 0.9 wt % KCl, and 0.2 wt % CaCl{sub 2}. The cracking was associated with the heat-affected zone of an autogenous weld that ran across the center of the coupon. Cracking was not observed in coupons exposed to the headspace gas above the solid mixture, or in coupons exposed to other mixtures with either no CaCl{sub 2} or 0.92 wt% CaCl{sub 2}. SCC was present where the 0.6 wt % water content exceeded the value needed to fully hydrate the available CaCl{sub 2}, but was absent where the water content was insufficient. These results reveal the significance of the relative humidity in the austenitic stainless steels environment to their susceptibility to corrosion. The relative humidity in the test environment was controlled by the water loading and the concentration of the hydrating salts such as CaCl{sub 2}. For each salt or salt mixture there is a threshold relative

  20. Teachers' Reactions to Children's Aggression

    ERIC Educational Resources Information Center

    Nesdale, Drew; Pickering, Kaye

    2006-01-01

    Drawing on social schema theory (Fiske & Taylor, 1991) and social identity theory (Tajfel & Turner, 1979), this study examined the impact on teachers' reactions to children's aggression of three variables, two of which were related to the aggressors and one was related to the teachers. Experienced female elementary school teachers (N=90) each read…

  1. Explorations of Affection and Aggression.

    ERIC Educational Resources Information Center

    Shuntich, Richard J.; Shapiro, Richard

    Considerable effort has been devoted to investigating various aspects of love and affection, but there have been few studies about direct expressions of affection. Relationships between gender composition of a dyad and the affection/aggression expressed by the dyad were examined as was the possibility of increasing the amount of affectionate…

  2. Risperidone and Explosive Aggressive Autism.

    ERIC Educational Resources Information Center

    Horrigan, Joseph P.; Barnhill, L. Jarrett

    1997-01-01

    In this study, 11 males with autism and mental retardation were administered risperidone. Substantial clinical improvement was noted almost immediately; patients with aggression, self-injury, explosivity, and poor sleep hygiene were most improved. The modal dose for optimal response was 0.5 mg bid. Weight gain was a significant side effect.…

  3. Male Responses to Female Aggression.

    ERIC Educational Resources Information Center

    Russell, Gordon W.; And Others

    1988-01-01

    Randomly assigned 60 male undergraduates to view film clip of professional lady wrestlers or of mud wrestling, or to no-film control. Both films produced negative changes in mood states, principally increase in aggression and decrease in social affection. Viewing films did not produce changes in men's acceptance of interpersonal violence against…

  4. The Passive Aggressive Conflict Cycle

    ERIC Educational Resources Information Center

    Whitson, Signe

    2013-01-01

    Understanding the Passive Aggressive Conflict Cycle (PACC) helps observers to be able to look beyond behavior and better understand what is occurring beneath the surface. This article presents a real-life example of a seemingly minor conflict between a teacher and child that elicited an apparent major overreaction by the adult. Also provided is a…

  5. Television Portrayal and Aggressive Behavior.

    ERIC Educational Resources Information Center

    Comstock, George

    This is a review of research relating to the attributes of portrayals which play a role in affecting aggressive behavior. The effects of portrayal can occur at any of three successive stages: acquisition, disinhibition/stimulation/arousal, performance. The older the individual, the more likely the influence is to be in all three stages of…

  6. Biochemistry and Aggression: Psychohematological Model.

    ERIC Educational Resources Information Center

    Foster, Hilliard G., Jr.; Spitz, Reuben T.

    1994-01-01

    Examines biochemical measures in a population of forensic psychiatric inpatients. Regression equations utilizing chemical and biological variables were developed and evaluated to determine their value in predicting the severity and frequency of aggression. Findings strongly suggest the presence of specific biochemical alteration among those…

  7. Implicit cognitive aggression among young male prisoners: Association with dispositional and current aggression.

    PubMed

    Ireland, Jane L; Adams, Christine

    2015-01-01

    The current study explores associations between implicit and explicit aggression in young adult male prisoners, seeking to apply the Reflection-Impulsive Model and indicate parity with elements of the General Aggression Model and social cognition. Implicit cognitive aggressive processing is not an area that has been examined among prisoners. Two hundred and sixty two prisoners completed an implicit cognitive aggression measure (Puzzle Test) and explicit aggression measures, covering current behaviour (DIPC-R) and aggression disposition (AQ). It was predicted that dispositional aggression would be predicted by implicit cognitive aggression, and that implicit cognitive aggression would predict current engagement in aggressive behaviour. It was also predicted that more impulsive implicit cognitive processing would associate with aggressive behaviour whereas cognitively effortful implicit cognitive processing would not. Implicit aggressive cognitive processing was associated with increased dispositional aggression but not current reports of aggressive behaviour. Impulsive implicit cognitive processing of an aggressive nature predicted increased dispositional aggression whereas more cognitively effortful implicit cognitive aggression did not. The article concludes by outlining the importance of accounting for implicit cognitive processing among prisoners and the need to separate such processing into facets (i.e. impulsive vs. cognitively effortful). Implications for future research and practice in this novel area of study are indicated. PMID:25857854

  8. Child exposure to serious life events, COMT, and aggression: Testing differential susceptibility theory.

    PubMed

    Hygen, Beate Wold; Belsky, Jay; Stenseng, Frode; Lydersen, Stian; Guzey, Ismail Cuneyt; Wichstrøm, Lars

    2015-08-01

    Both genetic and environmental factors contribute to individual differences in aggression. Catechol-O-methyltransferase Val158Met (COMT), a common, functional polymorphism, has been implicated in aggression and aggression traits, as have childhood experiences of adversity. It is unknown whether these effects are additive or interactional and, in the case of interaction, whether they conform to a diathesis-stress or differential susceptibility model. We examined Gene × Environment interactions between COMT and serious life events on measures of childhood aggression and contrasted these 2 models. The sample was composed of community children (N = 704); 355 were boys, and the mean age was 54.8 months (SD = 3.0). The children were genotyped for COMT rs4680 and assessed for serious life events and by teacher-rated aggression. Regression analysis showed no main effects of COMT and serious life events on aggression. However, a significant interactive effect of childhood serious life events and COMT genotype was observed: Children who had faced many serious life events and were Val homozygotes exhibited more aggression (p = .02) than did their Met-carrying counterparts. Notably, in the absence of serious life events, Val homozygotes displayed significantly lower aggression scores than did Met carriers (p = .03). When tested, this constellation of findings conformed to the differential susceptibility hypothesis: In this case, Val homozygotes are more malleable to the effect of serious life events on aggression and not simply more vulnerable to the negative effect of having experienced many serious life events. PMID:26053146

  9. Looking for reward in all the wrong places: dopamine receptor gene polymorphisms indirectly affect aggression through sensation-seeking.

    PubMed

    Chester, David S; DeWall, C Nathan; Derefinko, Karen J; Estus, Steven; Lynam, Donald R; Peters, Jessica R; Jiang, Yang

    2016-10-01

    Individuals with genotypes that code for reduced dopaminergic brain activity often exhibit a predisposition toward aggression. However, it remains largely unknown how dopaminergic genotypes may increase aggression. Lower-functioning dopamine systems motivate individuals to seek reward from external sources such as illicit drugs and other risky experiences. Based on emerging evidence that aggression is a rewarding experience, we predicted that the effect of lower-functioning dopaminergic functioning on aggression would be mediated by tendencies to seek the environment for rewards. Caucasian female and male undergraduates (N = 277) were genotyped for five polymorphisms of the dopamine D2 receptor (DRD2) gene; they reported their previous history of aggression and their dispositional reward-seeking. Lower-functioning DRD2 profiles were associated with greater sensation-seeking, which then predicted greater aggression. Our findings suggest that lower-functioning dopaminergic activity puts individuals at risk for violence because it motivates them to experience aggression's hedonically rewarding qualities. PMID:26592425

  10. Ammonia-oxidizing bacterial community composition in estuarine and oceanic environments assessed using a functional gene microarray.

    PubMed

    Ward, Bess B; Eveillard, Damien; Kirshtein, Julie D; Nelson, Joshua D; Voytek, Mary A; Jackson, George A

    2007-10-01

    The relationship between environmental factors and functional gene diversity of ammonia-oxidizing bacteria (AOB) was investigated across a transect from the freshwater portions of the Chesapeake Bay and Choptank River out into the Sargasso Sea. Oligonucleotide probes (70-bp) designed to represent the diversity of ammonia monooxygenase (amoA) genes from Chesapeake Bay clone libraries and cultivated AOB were used to construct a glass slide microarray. Hybridization patterns among the probes in 14 samples along the transect showed clear variations in amoA community composition. Probes representing uncultivated members of the Nitrosospira-like AOB dominated the probe signal, especially in the more marine samples. Of the cultivated species, only Nitrosospira briensis was detected at appreciable levels. Discrimination analysis of hybridization signals detected two guilds. Guild 1 was dominated by the marine Nitrosospira-like probe signal, and Guild 2's largest contribution was from upper bay (freshwater) sediment probes. Principal components analysis showed that Guild 1 was positively correlated with salinity, temperature and chlorophyll a concentration, while Guild 2 was positively correlated with concentrations of oxygen, dissolved organic carbon, and particulate nitrogen and carbon, suggesting that different amoA sequences represent organisms that occupy different ecological niches within the estuarine/marine environment. The trend from most diversity of AOB in the upper estuary towards dominance of a single type in the polyhaline region of the Bay is consistent with the declining importance of AOB with increasing salinity, and with the idea that AO-Archaea are the more important ammonia oxidizers in the ocean. PMID:17803777

  11. Ammonia-oxidizing bacterial community composition in estuarine and oceanic environments assessed using a functional gene microarray

    USGS Publications Warehouse

    Ward, B.B.; Eveillard, D.; Kirshtein, J.D.; Nelson, J.D.; Voytek, M.A.; Jackson, G.A.

    2007-01-01

    The relationship between environmental factors and functional gene diversity of ammonia-oxidizing bacteria (AOB) was investigated across a transect from the freshwater portions of the Chesapeake Bay and Choptank River out into the Sargasso Sea. Oligonucleotide probes (70-bp) designed to represent the diversity of ammonia monooxygenase (amoA) genes from Chesapeake Bay clone libraries and cultivated AOB were used to construct a glass slide microarray. Hybridization patterns among the probes in 14 samples along the transect showed clear variations in amoA community composition. Probes representing uncultivated members of the Nitrosospira-like AOB dominated the probe signal, especially in the more marine samples. Of the cultivated species, only Nitrosospira briensis was detected at appreciable levels. Discrimination analysis of hybridization signals detected two guilds. Guild 1 was dominated by the marine Nitrosospira-like probe signal, and Guild 2???s largest contribution was from upper bay (freshwater) sediment probes. Principal components analysis showed that Guild 1 was positively correlated with salinity, temperature and chlorophyll a concentration, while Guild 2 was positively correlated with concentrations of oxygen, dissolved organic carbon, and particulate nitrogen and carbon, suggesting that different amoA sequences represent organisms that occupy different ecological niches within the estuarine/marine environment. The trend from most diversity of AOB in the upper estuary towards dominance of a single type in the polyhaline region of the Bay is consistent with the declining importance of AOB with increasing salinity, and with the idea that AO-Archaea are the more important ammonia oxidizers in the ocean. ?? 2007 The Authors.

  12. A Psychoeducational Group for Aggressive Adolescent Girls

    ERIC Educational Resources Information Center

    Cummings, Anne L.; Hoffman, Sue; Leschied, Alan W.

    2004-01-01

    This article describes an eight-session psychoeducational group for aggressive adolescent girls. The content of the group sessions is based on research that has identified gender-specific issues related to aggression in adolescent girls, such as gender-role socialization, childhood abuse, relational aggression, horizontal violence, and girl…

  13. Aggressive behavior in children and adolescents.

    PubMed

    Zahrt, Dawn M; Melzer-Lange, Marlene D

    2011-08-01

    After completing this article, readers should be able to: 1. Describe the developmental stages of aggressive behavior in children.2. Know how to provide parents with support and resources in caring for a child who displays aggressive behavior.3. Delineate the prognosis for children who have aggressive behaviors. PMID:21807873

  14. Investigating Three Explanations of Women's Relationship Aggression

    ERIC Educational Resources Information Center

    Graham-Kevan, Nicola; Archer, John

    2005-01-01

    This study investigated explanations of women's partner aggression in a sample of 358 women. Women completed measures of physical aggression, control, and fear. Three explanations of women's partner aggression were explored: (a) that its use is associated with fear, (b) that it is reciprocal, and (c) that it is coercive. Each explanation received…

  15. Fantasy Aggression and the Catharsis Phenomenon

    ERIC Educational Resources Information Center

    Spiegel, Sharon Baron; Zelin, Martin

    1973-01-01

    The purpose of this study was to explore the effects of fantasy aggression on blood pressure, affective states, and probability of subsequent aggression. The results are inconclusive because of the limited range of fantasy stimuli used and the short amount of time allowed for aggression to occur. (Author/KM)

  16. The myth of the aggressive monkey.

    PubMed

    Reinhardt, Viktor

    2002-01-01

    Captive rhesus macaques are not naturally aggressive, but poor husbandry and handling practices can trigger their aggression toward conspecifics and toward the human handler. The myth of the aggressive monkey probably is based on often not taking into account basic ethological principles when managing rhesus macaques in the research laboratory setting. PMID:16221082

  17. Female Aggression and Violence: A Case Study

    ERIC Educational Resources Information Center

    Martin, Penelope E.

    2012-01-01

    Aggression and violence among adolescent females has received extension attention throughout the nation. Girls often employ relationally aggressive behaviors to resolve conflict, which often leads to physical aggression. The purpose of this study was to examine a girl fight from multiple perspectives to gain a better understanding of the causes…

  18. Understanding and Preventing Aggressive Responses in Youth.

    ERIC Educational Resources Information Center

    Studer, Jeannine

    1996-01-01

    Fighting violence requires a networking approach among schools, community, and parents. This article advises elementary school counselors: (a) focus on the causes of aggression; (b) identify children with the propensity for behaving aggressively; and (c) prevent aggressive responses in children and adolescents by introducing techniques and…

  19. Relational Aggression among Middle School Girls

    ERIC Educational Resources Information Center

    Dallape, Aprille

    2008-01-01

    The purpose of this study was to examine the correlates that define relational aggression among middle school girls, the relationships among these factors, and the association between the correlates of relational aggression and the type of relational aggression (e.g., verbal, withdrawal) exhibited among middle school girls. The findings of this…

  20. Feelings about Verbal Aggression: Justifications for Sending and Hurt from Receiving Verbally Aggressive Messages.

    ERIC Educational Resources Information Center

    Martin, Matthew M.; And Others

    1996-01-01

    Investigates whether receiving verbally aggressive messages was more hurtful depending on the source of the message; whether trait verbal aggression is justified; and whether the perceived hurt of verbally aggressive messages is related to a tendency to be verbally aggressive. Finds that messages from friends caused more hurt than messages from…

  1. Social Aggression on Television and Its Relationship to Children's Aggression in the Classroom

    ERIC Educational Resources Information Center

    Martins, Nicole; Wilson, Barbara J.

    2012-01-01

    A survey was conducted with over 500 children in grades K-5 to examine whether exposure to socially aggressive content was related to children's use of social aggression. The results of the survey revealed a significant relationship between exposure to televised social aggression and increased social aggression at school, but only for girls and…

  2. Effects of Aggressive vs. Nonaggressive Films on the Aggressive Behavior of Mentally Retarded Children.

    ERIC Educational Resources Information Center

    Evans, Charles

    Examined was the effect of viewing an aggressive film on the behavior of 22 moderately and mildly mentally retarded children (5-11 years old). Ss' doll playing was observed after they viewed a nonaggressive and an aggressive film. Results supported the hypothesis that Ss would exhibit more aggressive behavior following the aggressive than the…

  3. Studies of Scale Formation and Kinetics of Crofer 22 APU and Haynes 230 in Carbon Oxide-Containing Environment for SOFC Applications

    SciTech Connect

    Ziomek-Moroz, M.; Covino, B.S., Jr.; Holcomb, G.R.; Bullard, S.J.; Penner, L.R.

    2006-01-01

    Significant progress in reducing the operating temperature of SOFCs below 800oC may allow the use of chromia-forming metallic interconnects at a substantial cost savings. Hydrogen is the main fuel for all types of fuel cells except direct methanol fuel cells. Hydrogen can be generated from fossil fuels, including coal, natural gas, diesel, gasoline, other hydrocarbons, and oxygenates (e.g., methanol, ethanol, butanol, etc.). Carbon oxides present in the hydrogen fuel can cause significant performance problems due to carbon formation (coking). Also, literature data indicate that in CO/CO2 gaseous environments, metallic materials that gain their corrosion resistance due to formation of Cr2O3, could form stable chromium carbides. The chromium carbide formation causes depletion of chromium in these alloys. If the carbides oxidize, they form non-protective scales. Considering a potential detrimental effect of carbon oxides on iron- and nickel-base alloy stability, determining corrosion performance of metallic interconnect candidates in carbon oxide-containing environments at SOFC operating temperatures is a must. In this research, the corrosion behavior of Crofer 22 APU and Haynes 230 was studied in a CO-rich atmosphere at 750°C. Chemical composition of the gaseous environment at the outlet was determined using gas chromatography (GC). After 800 h of exposure to the gaseous environment the surfaces of the corroded samples were studied by scanning electron microscopy (SEM) equipped with microanalytical capabilities. X-ray diffraction (XRD) analysis was also used in this study.

  4. Oxidation and Corrosion of Ceramics and Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Jacobson, Nathan S.; Opila, Elizabeth J.; Lee, Kang N.

    2000-01-01

    Ceramics and ceramic matrix composites are candidates for numerous applications in high temperature environments with aggressive gases and possible corrosive deposits. There is a growing realization that high temperature oxidation and corrosion issues must be considered. There are many facets to these studies, which have been extensively covered in some recent reviews. The focus of this paper is on current research, over the past two years. In the authors' view, the most important oxidation and corrosion studies have focused on four major areas during this time frame. These are; (I) Oxidation of precursor-based ceramics; (II) Studies of the interphase material in ceramic matrix composites; (III) Water vapor interactions with ceramics, particularly in combustion environments; and (IV) Development of refractory oxide coatings for silicon-based ceramics. In this paper, we shall explore the most current work in each of these areas.

  5. Microbial oxidation of arsenite in a subarctic environment: diversity of arsenite oxidase genes and identification of a psychrotolerant arsenite oxidiser

    PubMed Central

    2010-01-01

    Background Arsenic is toxic to most living cells. The two soluble inorganic forms of arsenic are arsenite (+3) and arsenate (+5), with arsenite the more toxic. Prokaryotic metabolism of arsenic has been reported in both thermal and moderate environments and has been shown to be involved in the redox cycling of arsenic. No arsenic metabolism (either dissimilatory arsenate reduction or arsenite oxidation) has ever been reported in cold environments (i.e. < 10°C). Results Our study site is located 512 kilometres south of the Arctic Circle in the Northwest Territories, Canada in an inactive gold mine which contains mine waste water in excess of 50 mM arsenic. Several thousand tonnes of arsenic trioxide dust are stored in underground chambers and microbial biofilms grow on the chamber walls below seepage points rich in arsenite-containing solutions. We compared the arsenite oxidisers in two subsamples (which differed in arsenite concentration) collected from one biofilm. 'Species' (sequence) richness did not differ between subsamples, but the relative importance of the three identifiable clades did. An arsenite-oxidising bacterium (designated GM1) was isolated, and was shown to oxidise arsenite in the early exponential growth phase and to grow at a broad range of temperatures (4-25°C). Its arsenite oxidase was constitutively expressed and functioned over a broad temperature range. Conclusions The diversity of arsenite oxidisers does not significantly differ from two subsamples of a microbial biofilm that vary in arsenite concentrations. GM1 is the first psychrotolerant arsenite oxidiser to be isolated with the ability to grow below 10°C. This ability to grow at low temperatures could be harnessed for arsenic bioremediation in moderate to cold climates. PMID:20673331

  6. Mapping Brain Development and Aggression

    PubMed Central

    Paus, Tomás

    2005-01-01

    Introduction This article provides an overview of the basic principles guiding research on brain-behaviour relationships in general, and as applied to studies of aggression during human development in particular. Method Key literature on magnetic resonance imaging of the structure and function of a developing brain was reviewed. Results The article begins with a brief introduction to the methodology of techniques used to map the developing brain, with a special emphasis on magnetic resonance imaging (MRI). It then reviews briefly the current knowledge of structural maturation, assessed by MRI, of the human brain during childhood and adolescence. The last part describes some of the results of neuroimaging studies aimed at identifying neural circuits involved in various aspects of aggression and social cognition. Conclusion The article concludes by discussing the potential and limitations of the neuroimaging approach in this field. PMID:19030495

  7. Preventing aggressive behaviour in dogs.

    PubMed

    Orritt, Rachel

    2016-07-01

    Delegates from around the world met at the University of Lincoln on June 11 and 12 for the third annual UK Dog Bite Prevention and Behaviour conference. The conference, hosted by dog trainer Victoria Stilwell, brings together dog behaviour experts to discuss possible solutions to this public health issue. Rachel Orritt, who has been examining the perceptions, assessment and management of human-directed aggressive behaviour in dogs for her PhD, reports. PMID:27389748

  8. Lateralization of aggression in fish.

    PubMed

    Bisazza, Angelo; de Santi, Andrea

    2003-05-15

    Recent research has suggested that lateralization of aggressive behaviors could follow an homogeneous pattern among all vertebrates. A left eye/right hemisphere dominance in eliciting aggressive responses has been demonstrated for all groups of tetrapods but teleost fish for which data is lacking. Here we studied differential eye use during aggressive interactions in three species of teleosts: Gambusia holbrooki, Xenotoca eiseni and Betta splendens. In the first experiment we checked for lateralization in the use of the eyes while the subject was attacking its own mirror image. In order to confirm the results, other tests were performed on two species and eye preference was scored during attacks or displays directed toward a live rival. All three species showed a marked preference for using the right eye when attacking a mirror image or a live rival. Thus, the direction of asymmetry in fish appears the opposite to that shown by all the other groups of vertebrates. Hypotheses on the origin of the difference are discussed. PMID:12742249

  9. Neurobiology of Aggression and Violence

    PubMed Central

    Siever, Larry J.

    2014-01-01

    Acts of violence account for an estimated 1.43 million deaths worldwide annually. While violence can occur in many contexts, individual acts of aggression account for the majority of instances. In some individuals, repetitive acts of aggression are grounded in an underlying neurobiological susceptibility that is just beginning to be understood. The failure of “top-down” control systems in the prefrontal cortex to modulate aggressive acts that are triggered by anger provoking stimuli appears to play an important role. An imbalance between prefrontal regulatory influences and hyper-responsivity of the amygdala and other limbic regions involved in affective evaluation are implicated. Insufficient serotonergic facilitation of “top-down” control, excessive catecholaminergic stimulation, and subcortical imbalances of glutamatergic/ gabaminergic systems as well as pathology in neuropeptide systems involved in the regulation of affiliative behavior may contribute to abnormalities in this circuitry. Thus, pharmacological interventions such as mood stabilizers, which dampen limbic irritability, or selective serotonin reuptake inhibitors (SSRIs), which may enhance “top-down” control, as well as psychosocial interventions to develop alternative coping skills and reinforce reflective delays may be therapeutic. PMID:18346997

  10. Rural neighborhoods and child aggression.

    PubMed

    Bowen, Natasha K; Wretman, Christopher J

    2014-12-01

    Structural equation modeling with latent variables was used to evaluate the direct and mediated effects of a neighborhood risk factor (negative teen behaviors) on the parent-report aggressive behavior of 213 students in grades 3 through 5 attending a school in a low-income, rural community. Contagion and social control hypotheses were examined as well as hypotheses about whether the neighborhood served as a microsystem or exosystem for rural pre-adolescents. Analyses took into account the clustering of students and ordinal nature of the data. Findings suggest that rural neighborhoods may operate as both a microsystem and exosystem for children, with direct contagion effects on their aggressive behaviors as well as indirect social control effects through parenting practices. Direct effects on aggression were also found for parenting practices and child reports of friends' negative behaviors. Pre-adolescence may be a transitional stage, when influences of the neighborhood on child behavior begin to compete with influences of caregivers. Findings can inform the timing and targets of violence prevention in rural communities. PMID:25205545

  11. Neighborhood as a predictor of non-aggressive, but not aggressive, antisocial behaviors in adulthood

    PubMed Central

    Burt, S. Alexandra; Klump, Kelly L.; Kashy, Deborah A.; Gorman-Smith, Deborah; Neiderhiser, Jenae M.

    2015-01-01

    Background Prior meta-analytic work has highlighted important etiological distinctions between aggressive (AGG) and non-aggressive rule-breaking (RB) dimensions of antisocial behavior. Among these is the finding that RB is influenced by the environment more than is AGG. Relatively little research, however, has sought to identify the specific environmental experiences that contribute to this effect. Method The current study examined whether adults residing in the same neighborhood (N = 1,915 participants in 501 neighborhoods) were more similar in their AGG and RB than would be expected by chance. Analyses focused on simple multi-level models, with the participant as the lower-level unit and the neighborhood as the upper-level unit. Results Results revealed little-to-no evidence of neighborhood-level variance in AGG. By contrast, 11+% of the variance in RB could be predicted from participant neighborhood, results that persisted even when considering the possibility of genetic relatedness across participants and neighborhood selection effects. Moreover, 17% of this neighborhood-level variance in RB was accounted for by neighborhood structural characteristics and social processes. Discussion Findings bolster prior suggestions that broader contextual experiences, like the structural and social characteristics of one's neighborhood, contribute in a meaningful way to RB in particular. Our results also tentatively imply that this association may be environmental in origin. Future work should seek to develop additional, stronger designs capable of more clearly leveraging genetic un-relatedness to improve causal inferences regarding the environment. PMID:26040779

  12. Study in mice shows that an aggressive type of breast cancer is linked to an inflammatory protein

    Cancer.gov

    Aberrant expression of an inflammatory protein, nitric oxide synthase 2 (NOS2), may enhance the progression and metastasis of an aggressive and less common form of breast cancer, known as the estrogen receptor-negative type of disease.

  13. Mn-Oxide Minerals from a Terrestrial Cave Environment: Biomarkers for the Search for Life on Mars?

    NASA Technical Reports Server (NTRS)

    Spilde, M. N.; Brearley, A. J.; Papike, J. J.

    2001-01-01

    Mn-oxides are promising biomarkers because microbes greatly accelerate Mn-oxide formation rates and produce distinctive oxidation states. Mn minerals in terrestrial caves form subaerially and could conceivably be present in the subsurface of Mars. Additional information is contained in the original extended abstract.

  14. Antisocial personality disorder, alcohol, and aggression.

    PubMed

    Moeller, F G; Dougherty, D M

    2001-01-01

    Epidemiologic studies and laboratory research consistently link alcohol use with aggression. Not all people, however, exhibit increased aggression under the influence of alcohol. Recent research suggests that people with antisocial personality disorder (ASPD) may be more prone to alcohol-related aggression than people without ASPD. As a group, people with ASPD have higher rates of alcohol dependence and more alcohol-related problems than people without ASPD. Likewise, in laboratory studies, people with ASPD show greater increases in aggressive behavior after consuming alcohol than people without ASPD. The association between ASPD and alcohol-related aggression may result from biological factors, such as ASPD-related impairments in the functions of certain brain chemicals (e.g., serotonin) or in the activities of higher reasoning, or "executive," brain regions. Alternatively, the association between ASPD and alcohol-related aggression may stem from some as yet undetermined factor(s) that increase the risk for aggression in general. PMID:11496966

  15. REACTIVE AND PROACTIVE AGGRESSION IN ADOLESCENT MALES

    PubMed Central

    Fite, Paula J.; Raine, Adrian; Stouthamer-Loeber, Magda; Loeber, Rolf; Pardini, Dustin A.

    2010-01-01

    There is limited knowledge about the unique relations between adolescent reactive and proactive aggression and later psychosocial adjustment in early adulthood. Accordingly, this study prospectively examined associations between adolescent (mean age = 16) reactive and proactive aggression and psychopathic features, antisocial behavior, negative emotionality, and substance use measured 10 years later in early adulthood (mean age = 26). Study questions were examined in a longitudinal sample of 335 adolescent males. Path analyses indicate that after controlling for the stability of the outcome and the overlap between the two subtypes of aggression, reactive aggression is uniquely associated with negative emotionality, specifically anxiety, in adulthood. In contrast, proactive aggression is uniquely associated with measures of adult psychopathic features and antisocial behavior in adulthood. Both reactive and proactive aggression uniquely predicted substance use in adulthood, but the substances varied by subtype of aggression. Implications for findings are discussed. PMID:20589225

  16. [Pharmacological treatment of syndromes of aggressivity].

    PubMed

    Itil, T M

    1978-01-01

    In the treatment of violent-aggressive behavior, four major groups of drugs emerged: 1. Major tranquilizers in the treatment of aggressive-violent behavior associated with psychotic syndromes. 2. Anti-epileptic drugs such as diphenylhydantoin and barbiturates in the treatment of aggressive-violent behavior within the epileptic syndrome. 3. Psychostimulants in the treatment of aggressive behavior of adolescents and children within behavior disturbances. 4. Anti-male hormones such as cyproterone acetate in the treatment of violent-aggressive behavior associated with pathological sexual hyperactivity. Whereas each category of drug is predominantly effective in one type of aggressive syndrome, it may also be effective in other conditions as well. Aggression as a result of a personality disorder is most difficult to treat with drugs. PMID:34189

  17. Aggression after Traumatic Brain Injury: Prevalence & Correlates

    PubMed Central

    Rao, Vani; Rosenberg, Paul; Bertrand, Melaine; Salehinia, Saeed; Spiro, Jennifer; Vaishnavi, Sandeep; Rastogi, Pramit; Noll, Kathy; Schretlen, David J; Brandt, Jason; Cornwell, Edward; Makley, Michael; Miles, Quincy Samus

    2010-01-01

    Aggression after traumatic brain injury (TBI) is common but not well defined. Sixty-seven participants with first-time TBI were seen within three months of injury and evaluated for aggression. The prevalence of aggression was found to be 28.4% and to be predominantly verbal aggression. Post-TBI aggression was associated with new-onset major depression (p=0.02), poorer social functioning (p=0.04), and increased dependency on activities of daily living (p=0.03), but not with a history of substance abuse or adult/childhood behavioral problems. Implications of the study include early screening for aggression, evaluation for depression, and consideration of psychosocial support in aggressive patients. PMID:19996251

  18. Mindfulness-Based Program for Management of Aggression Among Youth: A Follow-up Study

    PubMed Central

    Sharma, Manoj Kumar; Sharma, Mahendra P.; Marimuthu, P.

    2016-01-01

    Background: Youth have shown indulgence in various high-risk behaviors and violent activities. Yoga-based approaches have been used for the management of psychological problems. The present work explores the role of mindfulness-based program in the management of aggression among youth. Materials and Methods: Sociodemographic information schedule, Buss-Perry Aggression Questionnaire, and World Health Organization quality of life were administered on 50 subjects in the age range of 18-25 years at pre- and post-mindfulness-based program level. Results: It revealed the presence of feeling of well-being and ability to relax themselves; changes in score of anger, hostility, physical, and verbal aggression; and enhancement of quality of life in the physical and environment domains at 1 month follow-up. Conclusions: Mindfulness-based program has shown changes in aggression expression/control and implies integration of it in available program for the management of aggression among youth. PMID:27335516

  19. Prevalence and Associated Factors of Physical, Verbal and Relational Aggression among Iranian Preschoolers

    PubMed Central

    Ghalehtaki, Reza; Ghazanfari, Arash; Daneshvar-fard, Maryam; Mohammadi, Mohammad Reza

    2013-01-01

    Objective Childhood aggression may lead to severe social disorders in adolescence and adulthood. Different psychiatric approaches are focused on preschool aged aggressive children. The aim of this study was to estimate the prevalence and associated factors of childhood direct and indirect aggression. Methods In this cross sectional study a total of 1403 children attending 43 kindergartens were assessed. Data were collected through a structured 46-item questionnaire investigating symptoms of physical, verbal and relational aggression which was completed by parents and teachers of day-care centers. Complex sample survey analysis and multivariate logistic regression method were used for data analysis. Results According to parents’ rating, the prevalence of physical,verbal and relational aggression, was 9.9% (95% CI=7.4%-12.4%), 6.3% (95% CI=5.0% -7.6%) and 1.6% (95%CI=1.0%-2.2%), respectively; while based on teachers’ rating the prevalence of physical,verbal and relational aggression were 10.9% (95% CI=8.9% -12.9%), 4.9%(95% CI=3.8% -6.0%) and 6% (95% CI=4.4% -7.6%), respectively. A wide range of family environment factors including living with a single parent, having a working mother, death of someone close to the child, and having less educated mother were significantly associated with different types of aggression; additionally, there was some evidence of a relationship between sex of the children and physical aggression, after controlling for other variables (p < 0.05). Conclusion This study revealed that children's family environment alongside internal factors plays an important role as an external factor in determining the child's potential aggressive behavior. Given this, to better prevent the aggressive behavior of children, intervention strategies should be planned for families and caregivers; specially mothers should receive training to use such strategies. PMID:24454423

  20. “Blurred Lines?”1 Sexual Aggression and Barroom Culture

    PubMed Central

    Graham, Kathryn; Bernards, Sharon; Osgood, D. Wayne; Abbey, Antonia; Parks, Michael; Flynn, Andrea; Dumas, Tara; Wells, Samantha

    2014-01-01

    patrons and staff that support sexual aggression and better management of the highly sexualized and sexist environments of most bars. PMID:24588839

  1. Brain Serotonin Receptors and Transporters: Initiation vs. Termination of Escalated Aggression

    PubMed Central

    Takahashi, Aki; Quadros, Isabel M.; de Almeida, Rosa M. M.; Miczek, Klaus A.

    2013-01-01

    Rationale Recent findings have shown a complexly regulated 5-HT system as it is linked to different kinds of aggression. Objective We focus on (1) phasic and tonic changes of 5-HT and (2) state and trait of aggression, and emphasize the different receptor subtypes, their role in specific brain regions, feed-back regulation and modulation by other amines, acids and peptides. Results New pharmacological tools differentiate the first three 5-HT receptor families and their modulation by GABA, glutamate and CRF. Activation of 5-HT1A, 5-HT1B and 5-HT2A/2C receptors in mesocorticolimbic areas, reduce species-typical and other aggressive behaviors. In contrast, agonists at 5-HT1A and 5-HT1B receptors in the medial prefrontal cortex or septal area can increase aggressive behavior under specific conditions. Activation of serotonin transporters reduce mainly pathological aggression. Genetic analyses of aggressive individuals have identified several molecules that affect the 5-HT system directly (e.g., Tph2, 5-HT1B, 5-HT transporter, Pet1, MAOA) or indirectly (e.g., Neuropeptide Y, αCaMKII, NOS, BDNF). Dysfunction in genes for MAOA escalates pathological aggression in rodents and humans, particularly in interaction with specific experiences. Conclusions Feedback to autoreceptors of the 5-HT1 family and modulation via heteroreceptors are important in the expression of aggressive behavior. Tonic increase of the 5-HT2 family expression may cause escalated aggression, whereas the phasic increase of 5-HT2 receptors inhibits aggressive behaviors. Polymorphisms in the genes of 5-HT transporters or rate-limiting synthetic and metabolic enzymes of 5-HT modulate aggression, often requiring interaction with the rearing environment. PMID:20938650

  2. Student nurses' perceptions of aggression: An exploratory study of defensive styles, aggression experiences, and demographic factors.

    PubMed

    Bilgin, Hulya; Keser Ozcan, Neslihan; Tulek, Zeliha; Kaya, Fadime; Boyacioglu, Nur Elcin; Erol, Ozgul; Arguvanli Coban, Sibel; Pazvantoglu, Ozan; Gumus, Kubra

    2016-06-01

    Throughout the clinical learning process, nursing students' perception of aggression might have implications in terms of their future professional behavior toward patients. Using a descriptive cross-sectional design, we investigated the relationships between student nurses' perceptions of aggression and their personal characteristics, defense styles, and a convenience sample of 1539 experiences of aggressive behavior in clinical practice. Information about the students' personal features, their clinical practice, and experiences of aggressive behavior was obtained by questionnaire. The Turkish version of the Perception of Aggression Scale and Defense Styles Questionnaire-40 were also used. Students were frequently exposed to verbal aggression from patients and their relatives. And perceived patient aggression negatively, perception of aggression were associated with sex, defense styles, feelings of safety, and experiences of aggressions during clinical practice. Of interest is the reality that student nurses should be prepared for untoward events during their training. PMID:26916604

  3. Factors influencing the aggressiveness elicited by marihuana in food-deprived rats.

    PubMed

    Carlini, E A; Hamaoui, A; Märtz, R M

    1972-04-01

    1. Aggressive behaviour was elicited in rats that had been deprived of food for 20 h daily (starved), by chronic administration of Cannabis sativa extract or (-)-Delta(9)-trans-tetrahydrocannabinol.2. The influence of intraperitoneal (i.p.) or oral glucose administration, cold environment, acidosis, and corn, and protein-free diets on this aggressiveness was studied.3. Intraperitoneal injections of glucose (100-1,600 mg/kg) did not alter the aggressiveness induced by marihuana in starved rats; glucose given orally, however, blocked this behaviour.4. Low temperature (14 degrees C) strongly potentiated the aggressive behaviour induced by marihuana in the starved rats.5. Lactic acid in doses capable of potentiating thiopental anaesthesia, failed to alter the marihuana-aggressiveness of starved rats or to facilitate this effect of marihuana in rats fed ad libitum. The same negative results were obtained with ammonium chloride.6. In rats fed ad libitum with protein-free or corn diets, marihuana administered chronically did not elicit aggressive behaviour. However, aggressiveness appeared when rats were fed for only 2 h daily on those diets.7. The results suggest that the stress of hunger (and not hypoglycaemia, acidosis or lack of specific nutrients due to starvation) is the factor that facilitates the development of aggressive behaviour by chronic administration of marihuana. PMID:5064930

  4. Gene expression and variation in social aggression by queens of the harvester ant Pogonomyrmex californicus.

    PubMed

    Helmkampf, Martin; Mikheyev, Alexander S; Kang, Yun; Fewell, Jennifer; Gadau, Jürgen

    2016-08-01

    A key requirement for social cooperation is the mitigation and/or social regulation of aggression towards other group members. Populations of the harvester ant Pogonomyrmex californicus show the alternate social phenotypes of queens founding nests alone (haplometrosis) or in groups of unrelated yet cooperative individuals (pleometrosis). Pleometrotic queens display an associated reduction in aggression. To understand the proximate drivers behind this variation, we placed foundresses of the two populations into social environments with queens from the same or the alternate population, and measured their behaviour and head gene expression profiles. A proportion of queens from both populations behaved aggressively, but haplometrotic queens were significantly more likely to perform aggressive acts, and conflict escalated more frequently in pairs of haplometrotic queens. Whole-head RNA sequencing revealed variation in gene expression patterns, with the two populations showing moderate differentiation in overall transcriptional profile, suggesting that genetic differences underlie the two founding strategies. The largest detected difference, however, was associated with aggression, regardless of queen founding type. Several modules of coregulated genes, involved in metabolism, immune system and neuronal function, were found to be upregulated in highly aggressive queens. Conversely, nonaggressive queens exhibited a striking pattern of upregulation in chemosensory genes. Our results highlight that the social phenotypes of cooperative vs. solitary nest founding tap into a set of gene regulatory networks that seem to govern aggression level. We also present a number of highly connected hub genes associated with aggression, providing opportunity to further study the genetic underpinnings of social conflict and tolerance. PMID:27178446

  5. Psychopharmacological treatment of aggression in schizophrenic patients.

    PubMed

    Brieden, T; Ujeyl, M; Naber, D

    2002-05-01

    Aggressive behavior is frequently observed in schizophrenic patients. More than 50 % of all psychiatric patients and 10 % of schizophrenic patients show aggressive symptoms varying from threatening behavior and agitation to assault. The pharmacological treatment of acute, persisting and repetitive aggression is a serious problem for other patients and staff members. Not only is violent behavior from mentally ill patients the most detrimental factor in their stigmatization, aggression is also a considerable direct source of danger for the patients themselves. Based on rather limited evidence, a wide variety of medications for the pharmacological treatment of aggression has been recommended: typical and atypical antipsychotics, benzodiazepines, mood stabilizers, beta-blockers and selective serotonin reuptake inhibitors (SSRIs). Most clinical information on treating aggression has been collected for atypical neuroleptics, particularly for clozapine. Several retrospective and open studies indicate its efficacy. Treatment duration of 6 months is recommended to induce a stable reduction of physical and verbal aggression. Severe side effects have very rarely been seen. At the moment, clozapine seems to be the first choice in aggression treatment. Within the last few years, about 10 articles were published showing that this is the most effective antiaggressive agent in the treatment of aggression and agitation in psychiatric patients, independent of psychiatric diagnosis. However, clozapine, like all the other substances used, does not have an established indication for the treatment of aggressive symptoms. Noncompliance with medication makes it difficult to choose the right preparation for the medication: tablets, liquids, intramuscular injections and readily soluble "FDDFs" are available. Ethical, juridical and methodological problems prevent controlled studies from establishing a reference in the treatment of aggression in mentally ill patients. This review summarizes

  6. The passive-aggressive organization.

    PubMed

    Kaplan, Robert S; Norton, David P

    2005-10-01

    Passive-aggressive organizations are friendly places to work: People are congenial, conflict is rare, and consensus is easy to reach. But, at the end of the day, even the best proposals fail to gain traction, and a company can go nowhere so imperturbably that it's easy to pretend everything is fine. Such companies are not necessarily saddled with mulishly passive-aggressive employees. Rather, they are filled with mostly well-intentioned people who are the victirms of flawed processes and policies. Commonly, a growing company's halfhearted or poorly thought-out attempts to decentralize give rise to multiple layers of managers, whose authority for making decisions becomes increasingly unclear. Some managers, as a result, hang back, while others won't own up to the calls they've made, inviting colleagues to second-guess or overturn the decisions. In such organizations, information does not circulate freely, and that makes it difficult for workers to understand the impact of their actions on company performance and for managers to correctly appraise employees' value to the organization. A failure to accurately match incentives to performance stifles initiative, and people do just enough to get by. Breaking free from this pattern is hard; a long history of seeing corporate initiatives ignored and then fade away tends to make people cynical. Often it's best to bring in an outsider to signal that this time things will be different. He or she will need to address every obstacle all at once: clarify decision rights; see to it that decisions stick; and reward people for sharing information and adding value, not for successfully negotiating corporate politics. If those steps are not taken, it's only a matter of time before the diseased elements of a passive-aggressive organization overwhelm the remaining healthy ones and drive the company into financial distress. PMID:16250627

  7. Monoamine oxidase A gene (MAOA) predicts behavioral aggression following provocation

    PubMed Central

    McDermott, Rose; Tingley, Dustin; Cowden, Jonathan; Frazzetto, Giovanni; Johnson, Dominic D. P.

    2009-01-01

    Monoamine oxidase A gene (MAOA) has earned the nickname “warrior gene” because it has been linked to aggression in observational and survey-based studies. However, no controlled experimental studies have tested whether the warrior gene actually drives behavioral manifestations of these tendencies. We report an experiment, synthesizing work in psychology and behavioral economics, which demonstrates that aggression occurs with greater intensity and frequency as provocation is experimentally manipulated upwards, especially among low activity MAOA (MAOA-L) subjects. In this study, subjects paid to punish those they believed had taken money from them by administering varying amounts of unpleasantly hot (spicy) sauce to their opponent. There is some evidence of a main effect for genotype and some evidence for a gene by environment interaction, such that MAOA is less associated with the occurrence of aggression in a low provocation condition, but significantly predicts such behavior in a high provocation situation. This new evidence for genetic influences on aggression and punishment behavior complicates characterizations of humans as “altruistic” punishers and supports theories of cooperation that propose mixed strategies in the population. It also suggests important implications for the role of individual variance in genetic factors contributing to everyday behaviors and decisions. PMID:19168625

  8. Aggressive Angiomyxoma with Perineal Herniation

    PubMed Central

    Narang, Seema; Kohli, Supreethi; Kumar, Vinod; Chandoke, Raj

    2014-01-01

    Aggressive angiomyxoma is a rare mesenchymal tumor involving the pelvic-perineal region. It occurs during the third and fourth decade of life and is predominantly seen in females. It presents clinically as a soft tissue mass in variable locations such as vulva, perianal region, buttock, or pelvis. Assessment of extent of the tumor by radiological evaluation is crucial for surgical planning; however, biopsy is essential to establish diagnosis. We present the radiological and pathological features seen in a 43-year-old female diagnosed with abdominal angiomyxoma with an unusual extension to the perineum. PMID:24987570

  9. Becoming Who We Are: A Theoretical Explanation of Gendered Social Structures and Social Networks that Shape Adolescent Interpersonal Aggression

    ERIC Educational Resources Information Center

    Smith, Paige Hall; White, Jacquelyn W.; Moracco, Kathryn E.

    2009-01-01

    A conceptualization of gendered interpersonal aggression that is grounded in the social ecological framework is presented to explicate factors in adolescents' gendered environments that give rise to aggression and victimization. The focus is on gendered social structures and social networks. Our framework for prevention suggests that violence…

  10. Problems in the study of rodent aggression.

    PubMed

    Blanchard, Robert J; Wall, Philip M; Blanchard, D Caroline

    2003-09-01

    Laboratory research has produced detailed descriptions of aggression and defense patterns in the rat, mouse, and hamster, showing strong similarities, but also some differences, across these species. Research on target sites for attack, in conjunction with analyses of the situational antecedents of attack behaviors and of responsivity of these to conditions that elicit fear, has also provided a strong basis for analysis of offensive and defensive aggression strategies and for identification of combinations of these modalities such as may occur in maternal aggression. These patterns have been empirically differentiated from phenomena such as play fighting or predation and compared for laboratory rodents and their wild ancestors. An array of tasks, suitable for use with pharmacological and experimental manipulations, is available for analysis of both aggression and defense. These developments should produce a firm basis for research using animal models to analyze a broad array of aggression-related phenomena, including systematic approaches to understanding the normal antecedents and consequences of each of several differentiable types of aggressive behavior. Despite this strong empirical and analytic background, laboratory animal aggression research has been in a period of decline, spanning several decades, relative to comparable research focusing on areas such as sexual behavior or stress. Problems that may have contributed to the relative neglect of aggression research include confusion about the interpretation of different tasks for eliciting aggression; difficulties and labor intensiveness of observational measures needed for an adequate differentiation of offensive and defensive behaviors; analytic difficulties stemming from the sensitivity of offensive aggression to the inhibitory effects of fear or defensiveness; lack of a clear relationship between categories of aggressive behavior as defined in animal studies and those used in human aggression research; and

  11. Pro-oxidant environment of the colon compared to the small intestine may contribute to greater cancer susceptibility.

    PubMed

    Sanders, Lisa M; Henderson, Cara E; Hong, Mee Young; Barhoumi, Rola; Burghardt, Robert C; Carroll, Raymond J; Turner, Nancy D; Chapkin, Robert S; Lupton, Joanne R

    2004-05-28

    The colon and small intestine have inherent differences (e.g. redox status) that may explain the variation in cancer occurrence at these two sites. This study examined basal and induced (oxidative challenge) reactive oxygen species (ROS) generation, antioxidant enzyme activity and oxidative DNA damage. Basal ROS and antioxidant enzyme activities in the colon were greater than in the small intestine. During oxidative stress, 8-oxo-deoxyguanosine (8-oxodG) DNA adducts in the colon exceeded levels in the small intestine concomitant with increased ROS. Thus the colon responds to oxidative stress less effectively than the small intestine, possibly contributing to increased cancer incidence at this site. PMID:15142673

  12. Ligand-Enhanced Abiotic Iron Oxidation and the Effects of Chemical versus Biological Iron Cycling in Anoxic Environments

    PubMed Central

    2013-01-01

    This study introduces a newly isolated, genetically tractable bacterium (Pseudogulbenkiania sp. strain MAI-1) and explores the extent to which its nitrate-dependent iron-oxidation activity is directly biologically catalyzed. Specifically, we focused on the role of iron chelating ligands in promoting chemical oxidation of Fe(II) by nitrite under anoxic conditions. Strong organic ligands such as nitrilotriacetate and citrate can substantially enhance chemical oxidation of Fe(II) by nitrite at circumneutral pH. We show that strain MAI-1 exhibits unambiguous biological Fe(II) oxidation despite a significant contribution (∼30–35%) from ligand-enhanced chemical oxidation. Our work with the model denitrifying strain Paracoccus denitrificans further shows that ligand-enhanced chemical oxidation of Fe(II) by microbially produced nitrite can be an important general side effect of biological denitrification. Our assessment of reaction rates derived from literature reports of anaerobic Fe(II) oxidation, both chemical and biological, highlights the potential competition and likely co-occurrence of chemical Fe(II) oxidation (mediated by microbial production of nitrite) and truly biological Fe(II) oxidation. PMID:23402562

  13. Sleep deprivation suppresses aggression in Drosophila

    PubMed Central

    Kayser, Matthew S; Mainwaring, Benjamin; Yue, Zhifeng; Sehgal, Amita

    2015-01-01

    Sleep disturbances negatively impact numerous functions and have been linked to aggression and violence. However, a clear effect of sleep deprivation on aggressive behaviors remains unclear. We find that acute sleep deprivation profoundly suppresses aggressive behaviors in the fruit fly, while other social behaviors are unaffected. This suppression is recovered following post-deprivation sleep rebound, and occurs regardless of the approach to achieve sleep loss. Genetic and pharmacologic approaches suggest octopamine signaling transmits changes in aggression upon sleep deprivation, and reduced aggression places sleep-deprived flies at a competitive disadvantage for obtaining a reproductive partner. These findings demonstrate an interaction between two phylogenetically conserved behaviors, and suggest that previous sleep experiences strongly modulate aggression with consequences for reproductive fitness. DOI: http://dx.doi.org/10.7554/eLife.07643.001 PMID:26216041

  14. What lies beneath the face of aggression?

    PubMed

    Carré, Justin M; Murphy, Kelly R; Hariri, Ahmad R

    2013-02-01

    Recent evidence indicates that a sexually dimorphic feature of humans, the facial width-to-height ratio (FWHR), is positively correlated with reactive aggression, particularly in men. Also, predictions about the aggressive tendencies of others faithfully map onto FWHR in the absence of explicit awareness of this metric. Here, we provide the first evidence that amygdala reactivity to social signals of interpersonal challenge may underlie the link between aggression and the FWHR. Specifically, amygdala reactivity to angry faces was positively correlated with aggression, but only among men with relatively large FWHRs. The patterns of association were specific to angry facial expressions and unique to men. These links may reflect the common influence of pubertal testosterone on craniofacial growth and development of neural circuitry underlying aggression. Amygdala reactivity may also represent a plausible pathway through which FWHR may have evolved to represent an honest indicator of conspecific threat, namely by reflecting the responsiveness of neural circuitry mediating aggressive behavior. PMID:22198969

  15. Sleep deprivation suppresses aggression in Drosophila.

    PubMed

    Kayser, Matthew S; Mainwaring, Benjamin; Yue, Zhifeng; Sehgal, Amita

    2015-01-01

    Sleep disturbances negatively impact numerous functions and have been linked to aggression and violence. However, a clear effect of sleep deprivation on aggressive behaviors remains unclear. We find that acute sleep deprivation profoundly suppresses aggressive behaviors in the fruit fly, while other social behaviors are unaffected. This suppression is recovered following post-deprivation sleep rebound, and occurs regardless of the approach to achieve sleep loss. Genetic and pharmacologic approaches suggest octopamine signaling transmits changes in aggression upon sleep deprivation, and reduced aggression places sleep-deprived flies at a competitive disadvantage for obtaining a reproductive partner. These findings demonstrate an interaction between two phylogenetically conserved behaviors, and suggest that previous sleep experiences strongly modulate aggression with consequences for reproductive fitness. PMID:26216041

  16. Calpains: markers of tumor aggressiveness?

    PubMed

    Roumes, Hélène; Leloup, Ludovic; Dargelos, Elise; Brustis, Jean-Jacques; Daury, Laetitia; Cottin, Patrick

    2010-05-15

    Rhabdomyosarcoma (RMS) are soft-tissue sarcoma commonly encountered in childhood. RMS cells can acquire invasive behavior and form metastases. The metastatic dissemination implicates many proteases among which are mu-calpain and m-calpain. Study of calpain expression and activity underline the deregulation of calpain activity in RMS. Analysis of kinetic characteristics of RMS cells, compared to human myoblasts LHCN-M2 cells, shows an important migration velocity in RMS cells. One of the major results of this study is the positive linear correlation between calpain activity and migration velocity presenting calpains as a marker of tumor aggressiveness. The RMS cytoskeleton is disorganized. Specifying the role of mu- and m-calpain using antisense oligonucleotides led to show that both calpains up-regulate alpha- and beta-actin in ARMS cells. Moreover, the invasive behavior of these cells is higher than that of LHCN-M2 cells. However, it is similar to that of non-treated LHCN-M2 cells, when calpains are inhibited. In summary, calpains may be involved in the anarchic adhesion, migration and invasion of RMS. The direct relationship between calpain activity and migration velocities or invasive behavior indicates that calpains could be considered as markers of tumor aggressiveness and as potential targets for limiting development of RMS tumor as well as their metastatic behavior. PMID:20193680

  17. Perspective: What is known, and not known, about the connections between alkane oxidation and metal uptake in alkanotrophs in the marine environment

    PubMed Central

    Kenney, Grace E.; Rosenzweig, Amy C.

    2014-01-01

    Article Summary Should iron and copper be added to the environment to stimulate the natural bioremediation of marine oil spills? The key enzymes that catalyze the oxidation of alkanes require either iron or copper, and the concentration of these ions in seawater is vanishingly low. Nevertheless, the dependence of alkane oxidation activity on external metal concentrations remains unclear. This perspective will summarize what is known about the co-regulation of alkane oxidation and metal acquisition and pose a series of critical questions to which, for the most part, we do not yet have answers. The paucity of answers points to the need for additional studies to illuminate the cellular biology connecting microbial growth on alkanes to the acquisition of metal ions. PMID:24710692

  18. Analysis of samples of reflector materials which are multicoated and metal samples with oxide coatings which have been exposed the space environment in LDEF testing

    NASA Technical Reports Server (NTRS)

    Neely, W. C.

    1992-01-01

    The use of low angle x-ray diffraction (XRD), x-ray photoelectron spectrometry (XPS), and Auger spectrometry have been tested as suitable methods for analysis of thin oxide films on metal substrates exposed to the space environment during Long Duration Exposure Facility (LDEF) testing. No significant changes in the composition of silicon monoxide overcoats on aluminum surfaces was found. XPS and Auger testing appear to be more suitable for ultrathin films than XRD.

  19. Men’s Aggression Toward Women

    PubMed Central

    Kim, Hyoun K.; Laurent, Heidemarie K.; Capaldi, Deborah M.; Feingold, Alan

    2008-01-01

    The present study examined the longitudinal course of men’s physical and psychological aggression toward a partner across 10 years, using a community sample of young couples (N = 194) from at-risk backgrounds. Findings indicated that men’s aggression decreased over time and that women’s antisocial behavior and depressive symptoms predicted changes in men’s aggression. This suggests the importance of studying social processes within the dyad to have a better understanding of men’s aggression toward a partner. PMID:19122790

  20. Neural control of aggression in Drosophila.

    PubMed

    Hoopfer, Eric D

    2016-06-01

    Like most animal species, fruit flies fight to obtain and defend resources essential to survival and reproduction. Aggressive behavior in Drosophila is genetically specified and also strongly influenced by the fly's social context, past experiences and internal states, making it an excellent framework for investigating the neural mechanisms that regulate complex social behaviors. Here, I summarize our current knowledge of the neural control of aggression in Drosophila and discuss recent advances in understanding the sensory pathways that influence the decision to fight or court, the neuromodulatory control of aggression, the neural basis by which internal states can influence both fighting and courtship, and how social experience modifies aggressive behavior. PMID:27179788

  1. Aggression and coexistence in female caribou

    USGS Publications Warehouse

    Weckerly, Floyd W.; Ricca, Mark A.

    2014-01-01

    Female caribou (Rangifer tarandus) are highly gregarious, yet there has been little study of the behavioral mechanisms that foster coexistence. Quantifying patterns of aggression between male and female, particularly in the only cervid taxa where both sexes grow antlers, should provide insight into these mechanisms. We asked if patterns of aggression by male and female caribou followed the pattern typically noted in other polygynous cervids, in which males display higher frequencies and intensity of aggression. From June to August in 2011 and 2012, we measured the frequency and intensity of aggression across a range of group sizes through focal animal sampling of 170 caribou (64 males and 106 females) on Adak Island in the Aleutian Archipelago, Alaska. Males in same-sex and mixed-sex groups and females in mixed-sex groups had higher frequencies of aggression than females in same-sex groups. Group size did not influence frequency of aggression. Males displayed more intense aggression than females. Frequent aggression in mixed-sex groups probably reflects lower tolerance of males for animals in close proximity. Female caribou were less aggressive and more gregarious than males, as in other polygynous cervid species.

  2. Video media-induced aggressiveness in children.

    PubMed

    Cardwell, Michael Steven

    2013-09-01

    Transmission of aggressive behaviors to children through modeling by adults has long been a commonly held psychological concept; however, with the advent of technological innovations during the last 30 years, video media-television, movies, video games, and the Internet-has become the primary model for transmitting aggressiveness to children. This review explores the acquisition of aggressive behaviors by children through modeling behaviors in violent video media. The impact of aggressive behaviors on the child, the family, and society is addressed. Suggestive action plans to curb this societal ill are presented. PMID:24002556

  3. Gibbon Aggression During Introductions: An International Survey.

    PubMed

    Harl, Heather; Stevens, Lisa; Margulis, Susan W; Petersen, Jay

    2016-01-01

    Little is known regarding the prevalence of aggression seen during introductions of captive gibbons (Hylobatidae). In this study, an online survey was developed to quantify and collect contextual details regarding the frequency and types of aggression seen during introductions of captive gibbons (Hylobatidae). Nineteen percent of institutions (17 institutions) reported observing aggression, and 6 of these institutions recorded multiple instances of aggression, though a vast majority of these cases resulted in mild injuries or none at all. The female was the primary aggressor in 23% of cases, the male was the primary aggressor in 58% of cases, and both were the primary aggressor in 1 case. Although these aggressive interactions were often not associated with a known cause, 27% of cases were associated with food displacement. In most cases, management changes, including trying new pairings, greatly reduced situational aggression, suggesting that individual personalities may play a factor in aggression. These data begin to explain the extent of aggression observed in captive gibbons; future studies will address possible correlations with aggression and introduction techniques. PMID:26963568

  4. Intimate partner aggression and women's work outcomes.

    PubMed

    LeBlanc, Manon Mireille; Barling, Julian; Turner, Nick

    2014-10-01

    Using conservation of resources theory, we examined the relationship between intimate partner aggression enacted against heterosexual women and 3 types of work-related outcomes for these women: withdrawal while at work (i.e., cognitive distraction, work neglect), withdrawal from work (i.e., partial absenteeism, intentions to quit), and performance. In Study 1, we compared withdrawal both at and from work across 3 clinically categorized groups of women (n = 50), showing that experiencing physical aggression is related to higher work neglect. We replicated and extended these findings in Study 2 using a community sample of employed women (n = 249) by considering the incremental variance explained by both physical aggression and psychological aggression on these same outcomes. Results showed that physical aggression predicted higher levels of withdrawal both at and from work, with psychological aggression predicting additional variance in partial absenteeism over and above the effects of physical aggression. Study 3 extended the model to include academic performance as an outcome in a sample of female college students (n = 122) in dating relationships. Controlling for the women's conscientiousness, psychological aggression predicted lower academic performance after accounting for the effects of physical aggression. We discuss theoretical and practical implications of these results, as well as directions for future research. PMID:25068818

  5. Molecular Analysis of the Diversity of Sulfate-Reducing and Sulfur-Oxidizing Prokaryotes in the Environment, Using aprA as Functional Marker Gene▿ †

    PubMed Central

    Meyer, Birte; Kuever, Jan

    2007-01-01

    The dissimilatory adenosine-5′-phosposulfate reductase is a key enzyme of the microbial sulfate reduction and sulfur oxidation processes. Because the alpha- and beta-subunit-encoding genes, aprBA, are highly conserved among sulfate-reducing and sulfur-oxidizing prokaryotes, they are most suitable for molecular profiling of the microbial community structure of the sulfur cycle in environment. In this study, a new aprA gene-targeting assay using a combination of PCR and denaturing gradient gel electrophoresis is presented. The screening of sulfate-reducing and sulfur-oxidizing reference strains as well as the analyses of environmental DNA from diverse habitats (e.g., microbial mats, invertebrate tissue, marine and estuarine sediments, and filtered hydrothermal water) by the new primer pair revealed an improved microbial diversity coverage and less-pronounced template-to-PCR product bias in direct comparison to those of the previously published primer set (B. Deplancke, K. R. Hristova, H. A. Oakley, V. J. McCracken, R. Aminov, R. I. Mackie, and H. R. Gaskins, Appl. Environ. Microbiol. 66:2166-2174, 2000). The concomitant molecular detection of sulfate-reducing and sulfur-oxidizing prokaryotes was confirmed. The new assay was applied in comparison with the 16S rRNA gene-based analysis to investigate the microbial diversity of the sulfur cycle in sediment, seawater, and manganese crust samples from four study sites in the area of the Lesser Antilles volcanic arc, Caribbean Sea (Caribflux project). The aprA gene-based approach revealed putative sulfur-oxidizing Alphaproteobacteria of chemolithoheterotrophic lifestyle to have been abundant in the nonhydrothermal sediment and water column. In contrast, the sulfur-based microbial community that inhabited the surface of the volcanic manganese crust was more complex, consisting predominantly of putative chemolithoautotrophic sulfur oxidizers of the Betaproteobacteria and Gammaproteobacteria. PMID:17921272

  6. Mechanism of Internal Oxidation of Alloy 617 in He-CO-CO2 Environments at 1123 K (850 °C)

    NASA Astrophysics Data System (ADS)

    Gulsoy, Gokce; Was, Gary S.

    2015-01-01

    Alloy 617 was exposed in Cr-Cr2O3 Rhines pack and in He-CO-CO2 gas with the goal of determining the mechanisms that govern the rapid internal aluminum oxidation kinetics of the alloy at 1123 K (850 °C). The predominant mechanism is the accelerated oxygen transport along the incoherent Al2O3-metal interfaces in the internal oxidation zone of Alloy 617, which results in values of oxygen diffusion coefficients up to five orders of magnitude greater than the bulk oxygen diffusion coefficient in pure nickel at 1123 K (850 °C). Another contribution to the rapid internal oxidation is the gas permeability of Cr2O3, which results in enhanced oxygen dissolution in the alloy. Despite formation of a surface Cr2O3 film, the dissolved oxygen concentration attained in Alloy 617 in He-CO-CO2 environments is a factor of 4 greater than that established by the dissociation oxygen partial pressure of Cr2O3 in the Rhines pack exposure. The dissolved oxygen concentrations and oxygen diffusion coefficient values established in this study are used to determine that internal oxidation of Alloy 617 in He-CO-CO2 environments can be mitigated by increasing the Al concentration of the alloy at least to 5.0 at. pct.

  7. Effects of viewing relational aggression on television on aggressive behavior in adolescents: A three-year longitudinal study.

    PubMed

    Coyne, Sarah M

    2016-02-01

    Most researchers on media and aggression have examined the behavioral effects of viewing physical aggression in the media. Conversely, in the current study, I examined longitudinal associations between viewing relational aggression on TV and subsequent aggressive behavior. Participants included 467 adolescents who completed a number of different questionnaires involving media and aggression at 3 different time points. Results revealed that viewing relational aggression on TV was longitudinally associated with future relational aggression. However, early levels of relational aggression did not predict future exposure to televised relational aggression. Conversely, there was a bidirectional relationship between TV violence and physical aggression over time. No longitudinal evidence was found for a general effect of viewing TV, as all significant media effects were specific to the type of aggression viewed. These results support the general aggression model and suggest that viewing relational aggression in the media can have a long-term effect on aggressive behavior during adolescence. PMID:26595354

  8. Comparison of Effect of Two-Hour Exposure to Forest and Urban Environments on Cytokine, Anti-Oxidant, and Stress Levels in Young Adults

    PubMed Central

    Im, Su Geun; Choi, Han; Jeon, Yo-Han; Song, Min-Kyu; Kim, Won; Woo, Jong-Min

    2016-01-01

    The purpose of this study was to investigate the effect of two-hour exposure to a forest environment on cytokine, anti-oxidant and stress levels among university students and to compare the results to those measured in urban environments. Forty-one subjects were recruited. For our crossover design, subjects were divided into two groups based on similar demographic characteristics. Group A remained in the urban environment and was asked to perform regular breathing for 2 h. Blood samples were collected and the serum levels of cytokines including interleukin-6 (IL-6), IL-8, tumor necrosis factor-α (TNF-α), and glutathione peroxidase (GPx) were examined. Subjects were moved to a small town in a rural area for an equal amount of time to exclude carryover effects, and then remained for another 2 h in a forest environment. The second set of blood samples was collected to assess the effect of exposure to the forest environment. Using the same method, Group B was first exposed to the forest environment, followed by exposure to the urban environment. Blood samples collected after the subjects were exposed to the forest environment showed significantly lower levels of IL-8 and TNF-α compared to those in samples collected after urban environment exposure (10.76 vs. 9.21, t = 4.559, p < 0.001, and 0.97 vs. 0.87, t = 4.130, p < 0.001). The GPx concentration increased significantly after exposure to the forest environment (LnGPx = 5.09 vs. LnGPx = 5.21, t = −2.039, p < 0.05). PMID:27347982

  9. Comparison of Effect of Two-Hour Exposure to Forest and Urban Environments on Cytokine, Anti-Oxidant, and Stress Levels in Young Adults.

    PubMed

    Im, Su Geun; Choi, Han; Jeon, Yo-Han; Song, Min-Kyu; Kim, Won; Woo, Jong-Min

    2016-01-01

    The purpose of this study was to investigate the effect of two-hour exposure to a forest environment on cytokine, anti-oxidant and stress levels among university students and to compare the results to those measured in urban environments. Forty-one subjects were recruited. For our crossover design, subjects were divided into two groups based on similar demographic characteristics. Group A remained in the urban environment and was asked to perform regular breathing for 2 h. Blood samples were collected and the serum levels of cytokines including interleukin-6 (IL-6), IL-8, tumor necrosis factor-α (TNF-α), and glutathione peroxidase (GPx) were examined. Subjects were moved to a small town in a rural area for an equal amount of time to exclude carryover effects, and then remained for another 2 h in a forest environment. The second set of blood samples was collected to assess the effect of exposure to the forest environment. Using the same method, Group B was first exposed to the forest environment, followed by exposure to the urban environment. Blood samples collected after the subjects were exposed to the forest environment showed significantly lower levels of IL-8 and TNF-α compared to those in samples collected after urban environment exposure (10.76 vs. 9.21, t = 4.559, p < 0.001, and 0.97 vs. 0.87, t = 4.130, p < 0.001). The GPx concentration increased significantly after exposure to the forest environment (LnGPx = 5.09 vs. LnGPx = 5.21, t = -2.039, p < 0.05). PMID:27347982

  10. Measurements to understand the role of the sub Arctic environment on boundary layer ozone, gaseous mercury and bromine oxide concentrations

    NASA Astrophysics Data System (ADS)

    Netcheva, S.; Bottenheim, J.; Staebler, R.; Steffen, A.; Bobrowski, N.; Moores, J.

    2009-04-01

    Marine Boundary Layer spring time ozone (O3) and Gaseous Elemental Mercury (GEM) depletion episodes in Polar Regions and the role played by reactive halogen species have been studied for several years. Understanding of the photochemistry involved has improved significantly in the last few years, but many questions remain. The key in filling many gaps of information is in conducting systematic measurements over freezing and thawing surfaces of big water basins in Polar Regions where depletion episodes are thought to originate. Regardless of extensive research in the field, data sets collected over the ice are limited due to logistics and engineering challenges. The fast changing Arctic environment with its potential implications for climate change and human and ecosystem health demand urgent development of a predictive capability that could only be achieved by complete quantitative understanding of these phenomena. The Out On The Ice (OOTI) mini atmospheric chemistry laboratory was developed in 2004 specifically to permit collecting data at remote locations in an autonomous way. The system is battery powered, easily transported by snowmobile and quickly deployed at a target location. The equipment has undergone multiple engineering and instrumentation improvements. In its current version, it conducts fully automated measurements of O3, GEM and carbon dioxide (CO2) simultaneously at two levels: right above a surface of interest and at 2.5 meters. This is accomplished by utilizing two identical sets of instruments (2B for O3 and Gardis for GEM), or by continuous valve switching (CO2). A vertical profile of bromine oxide is determined by scanning the collecting optics of a Differential Optical Absorption Spectrometer through different elevation angles. Furthermore a full set of meteorological data is acquired in parallel with the chemical measurements in order to evaluate environmental and air mass transport contributions. We will present results from data collected

  11. Enhanced photocatalytic oxidation of gaseous elemental mercury by TiO2 in a high temperature environment.

    PubMed

    Shen, Huazhen; Ie, Iau-Ren; Yuan, Chung-Shin; Hung, Chung-Hsuang; Chen, Wei-Hsiang; Luo, Jinjing; Jen, Yi-Hsiu

    2015-05-30

    The photo-oxidation of Hg(0) in a lab-scale reactor by titanium dioxide (TiO2) coated on the surface of glass beads was investigated at high temperatures. TiO2 was calcinated at four different temperatures of 300 °C, 400 °C, 500 °C and 600 °C (noted as Ti300, Ti400, Ti500 and Ti600) and characterized for its physicochemical properties. The calcinated TiO2 coating on the glass beads was then tested to compare the photo-oxidation efficiencies of Hg(0) with an incident light of 365 nm. The results showed that the oxidation efficiencies of Hg(0) for Ti400 and Ti500 were higher than those of Ti300 and Ti600. To enhance the photo-oxidation efficiency of Hg(0), Ti400 was selected to examine the wave lengths (λ) of 254 nm, 365 nm and visible light with various influent Hg(0) concentrations. The effects of irradiation strength and the presence of oxygen on the photo-oxidation efficiency of Hg(0) were further investigated, respectively. This study revealed that the wave length (λ) of 254 nm could promote the photo-oxidation efficiency of Hg(0) at 140 and 160 °C, while increasing the influent Hg(0) concentration and could enhance the photo-oxidation rate of Hg(0). However, the influence of 5% O2 present in the flue gas for the enhancement of Hg(0) oxidation was limited. Moreover, the intensity of the incident wave length of 365 nm and visible light were demonstrated to boost the photo-oxidation efficiency of Hg(0) effectively. PMID:25733397

  12. Daily Associations among Anger Experience and Intimate Partner Aggression within Aggressive and Nonaggressive Community Couples

    PubMed Central

    Crane, Cory A.; Testa, Maria

    2014-01-01

    Anger is an empirically established precipitant to aggressive responding toward intimate partners. The current investigation examined the effects of anger, as experienced by both partners, as well as gender and previous aggression, on in vivo intimate partner aggression using a prospective daily diary methodology. Participants (N = 118 couples) individually provided 56 consecutive, daily reports of affective experience and partner aggression. Multilevel models were estimated using the Actor Partner Interdependence Model framework to analyze the daily associations between anger and partner aggression perpetration among male and female participants as moderated by aggression history. Results revealed that both Actor and Partner anger were generally associated with subsequently reported daily conflict. Further, increases in daily Partner anger were associated with corresponding increases in partner aggression among females who reported high anger and males, regardless of their own anger experience. Increases in Actor anger were associated with increases in daily partner aggression only among previously aggressive females. Previously aggressive males and females consistently reported greater perpetration than their nonaggressive counterparts on days of high Actor anger experience. Results emphasize the importance of both Actor and Partner factors in partner aggression and suggest that female anger may be a stronger predictor of both female-to-male and male-to-female partner aggression than male anger, when measured at the daily level. PMID:24866529

  13. Media depictions of physical and relational aggression: connections with aggression in young adults' romantic relationships.

    PubMed

    Coyne, Sarah M; Nelson, David A; Graham-Kevan, Nicola; Tew, Emily; Meng, K Nathan; Olsen, Joseph A

    2011-01-01

    Various studies have found that viewing physical or relational aggression in the media can impact subsequent engagement in aggressive behavior. However, this has rarely been examined in the context of relationships. Accordingly, the aim of this study was to examine the connection between viewing various types of aggression in the media and perpetration of aggression against a romantic partner. A total of 369 young adults completed a variety of questionnaires asking for their perpetration of various forms of relationship aggression. Participants' exposure to both physical and relational aggression in the media was also assessed. As a whole, we found a relationship between viewing aggression in the media and perpetration of aggression; however, this depended on the sex of the participant and the type of aggression measured. Specifically, exposure to physical violence in the media was related to engagement in physical aggression against their partner only for men. However, exposure to relational aggression in the media was related to romantic relational aggression for both men and women. PMID:21046605

  14. Competitive Aggression without Interaction: Effects of Competitive versus Cooperative Instructions on Aggressive Behavior in Video Games.

    ERIC Educational Resources Information Center

    Anderson, Craig A.; Morrow, Melissa

    1995-01-01

    Extended and tested Deutsch's theory of competition effects. Predicted that people view competitive situations as inherently more aggressive than cooperative ones. Predicted that leading people to think of an aggressive situation in competitive terms would increase aggressive behavior. Increase of kill ratio occurred in absence of changes in…

  15. Predicting Aggressive Behavior in Children with the Help of Measures of Implicit and Explicit Aggression

    ERIC Educational Resources Information Center

    Grumm, Mandy; Hein, Sascha; Fingerle, Michael

    2011-01-01

    Aggressive behavior between children in schools is a topic that receives much interest as violence and aggressive behavior cause many maladaptive social outcomes in the school setting. In the current study the Implicit Association Test (IAT) was adapted as a measure of children's implicit aggression, by assessing the association of the self…

  16. The Relationship of Aggression and Bullying to Social Preference: Differences in Gender and Types of Aggression

    ERIC Educational Resources Information Center

    Lee, Eunju

    2009-01-01

    With 338 fifth-grade students as subjects, this study found the variations in the relation between school bullying and social preference as a function of gender and types of aggressive behavior utilized. Aggressive boys were likely to be rejected by peers, whereas aggressive girls were both rejected and accepted by peers. Children nominated…

  17. Relational and Overt Aggression in Urban India: Associations with Peer Relations and Best Friends' Aggression

    ERIC Educational Resources Information Center

    Bowker, Julie C.; Ostrov, Jamie M.; Raja, Radhi

    2012-01-01

    This study explored the associations between relational and overt aggression and social status, and tested whether the peer correlates of aggression vary as a function of best friends' aggression during early adolescence in urban India. One hundred and ninety-four young adolescents from primarily middle-to-upper-class families in Surat, India…

  18. Stability of Aggression during Early Adolescence as Moderated by Reciprocated Friendship Status and Friend's Aggression

    ERIC Educational Resources Information Center

    Adams, Ryan E.; Bukowski, William M.; Bagwell, Catherine

    2005-01-01

    The effect of friendship reciprocation and friend aggression on the stability of aggression across a 6-month period following the transition to secondary school was studied in a sample of 298 Grade 6 children from a predominately white, middle-class, Midwestern American community. The stability of aggression was generally high but it varied as a…

  19. Characterizing Aggressive Behavior with the Impulsive/Premeditated Aggression Scale among Adolescents with Conduct Disorder

    PubMed Central

    Mathias, Charles W.; Stanford, Matthew S.; Marsh, Dawn M.; Frick, Paul J.; Moeller, F. Gerard; Swann, Alan C.; Dougherty, Donald M.

    2007-01-01

    This study extends the use of the Impulsive/Premeditated Aggression Scale for subtyping aggressive behavior among adolescents with Conduct Disorder. Of the Conduct Disorder symptoms, aggression has the strongest prognostic and treatment implications. While aggression is a complex construct, convergent evidence supports a dichotomy of impulsive and premeditated aggressive subtypes that are qualitatively different from one another in terms of phenomenology and neurobiology. Previous attempts at measuring subtypes of aggression in children and adults are not clearly generalizable to adolescents. Sixty-six adolescents completed a questionnaire for characterizing aggression (Impulsive/Premeditated Aggression Scale), along with standard measures of personality and general functioning. Principal components analysis demonstrated two stable factors of aggression with good internal consistency and construct validity. Compared to the premeditated aggression factor, the impulsive aggression factor was associated with a broader range of personality, thought, emotional, and social problems. As in the adult and child literature, characterization of aggressive behavior into two subtypes appears to be relevant to understanding individual differences among adolescents with Conduct Disorder. PMID:17383014

  20. Role Stress and Aggression among Young Adults: The Moderating Influences of Gender and Adolescent Aggression

    ERIC Educational Resources Information Center

    Liu, Ruth X.; Kaplan, Howard B.

    2004-01-01

    Using data provided by a panel of non-Hispanic white respondents, this study explored whether aggressive response to severe role stress during early adulthood depends on gender and on an adolescent history of aggression. Logistic regression analysis yielded these findings: Men who reported aggression during early adolescence were significantly…

  1. Antiepileptics for aggression and associated impulsivity

    PubMed Central

    Huband, Nick; Ferriter, Michael; Nathan, Rajan; Jones, Hannah

    2014-01-01

    Background Aggression is a major public health issue and is integral to several mental health disorders. Antiepileptic drugs may reduce aggression by acting on the central nervous system to reduce neuronal hyper-excitability associated with aggression. Objectives To evaluate the efficacy of antiepileptic drugs in reducing aggression and associated impulsivity. Search methods We searched CENTRAL, MEDLINE, EMBASE, CINAHL, PsycINFO, metaRegister of Controlled Trials (mRCT) and ClinicalTrials.gov to April 2009. We also searched Cochrane Schizophrenia Group’s register of trials on aggression, National Research Record and handsearched for studies. Selection criteria Prospective, placebo-controlled trials of antiepileptic drugs taken regularly by individuals with recurrent aggression to reduce the frequency or intensity of aggressive outbursts. Data collection and analysis Three authors independently selected studies and two authors independently extracted data. We calculated standardised mean differences (SMDs), with odds ratios (ORs) for dichotomous data. Main results Fourteen studies with data from 672 participants met the inclusion criteria. Five different antiepileptic drugs were examined. Sodium valproate/divalproex was superior to placebo for outpatient men with recurrent impulsive aggression, for impulsively aggressive adults with cluster B personality disorders, and for youths with conduct disorder, but not for children and adolescents with pervasive developmental disorder. Carbamazepine was superior to placebo in reducing acts of self-directed aggression in women with borderline personality disorder, but not in children with conduct disorder. Oxcarbazepine was superior to placebo for verbal aggression and aggression against objects in adult outpatients. Phenytoin was superior to placebo on the frequency of aggressive acts in male prisoners and in outpatient men including those with personality disorder, but not on the frequency of ‘behavioral incidents’ in

  2. Effect of oxidizing environment on the strength and oxidation kinetics of HTGR graphites. Part I. Reactivity and strength loss of H451, PGX and IG-11 graphites

    SciTech Connect

    Eto, M.; Growcock, F.B.

    1981-09-01

    The effects of oxidizing atmosphere and temperature on the reactivities and strengths of PGX, H451, and IG-11 were examined. Preliminary measurements of the oxidation kinetics of these graphites in H/sub 2/O-, CO/sub 2/- and O/sub 2/-containing atmospheres indicated that the reactivities of H451 graphite toward O/sub 2/ and H/sub 2/O are quite similar to those of IG-11 graphite. The apparent activation energy for oxidation of these in O/sub 2/ were estimated to be approx. 175 kJ/mol while that in H/sub 2/O is probably approx. 200 kJ/mol. The apparent activation energy of IG-11 graphite oxidized in CO/sub 2/ is 255 +- 18 kJ/mol. PGX graphite was found to be quite variable in its reactivity toward H/sub 2/O. A linear dependence with (Fe) was determined, but other intrinsic properties were found to affect its absolute reactivity by as much as a factor of X50.

  3. 40 CFR 1066.831 - Exhaust emission test procedures for aggressive driving.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Exhaust emission test procedures for aggressive driving. 1066.831 Section 1066.831 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES Exhaust Emission Test Procedures for Motor Vehicles § 1066.831 Exhaust emission...

  4. Hypoglycemia and aggression: a review.

    PubMed

    Benton, D

    1988-08-01

    The popular notion that a tendency to develop low levels of blood glucose is the cause of a range of behavioral problems is reviewed. It is concluded that it is inappropriate to use the glucose tolerance test as a test of the tendency to develop reactive hypoglycemia. Instead, a meal tolerance test, in which glucose is administered in the presence of fat and protein, should be the method of choice. The use of a meal tolerance test strongly suggests that reactive hypoglycemia rarely results, except in a few exceptional individuals. Three situations are described in which a correlation between a tendency to develop moderately low levels of blood glucose during a glucose tolerance test (not hypoglycemic values) and the tendency to act aggressively have been reported. The significance of these data is unclear but several possible mechanisms by which glucose may influence behavior are discussed. PMID:3053477

  5. Harsh Parenting in Relation to Child Emotion Regulation and Aggression

    PubMed Central

    Chang, Lei; Schwartz, David; Dodge, Kenneth A.; McBride-Chang, Catherine

    2009-01-01

    This study presents a model of harsh parenting that has an indirect effect, as well as a direct effect, on child aggression in the school environment through the mediating process of child emotion regulation. Tested on a sample of 325 Chinese children and their parents, the model showed adequate goodness of fit. Also investigated were interaction effects between parents’ and children’s gender. Mothers’ harsh parenting affected child emotion regulation more strongly than fathers’, whereas harsh parenting emanating from fathers had a stronger effect on child aggression. Fathers’ harsh parenting also affected sons more than daughters, whereas there was no gender differential effect with mothers’ harsh parenting. These results are discussed with an emphasis on negative emotionality as a potentially common cause of family perturbations, including parenting and child adjustment problems. PMID:14640808

  6. Efficient anti-corrosive coating of cold-rolled steel in a seawater environment using an oil-based graphene oxide ink

    NASA Astrophysics Data System (ADS)

    Singhbabu, Y. N.; Sivakumar, B.; Singh, J. K.; Bapari, H.; Pramanick, A. K.; Sahu, Ranjan K.

    2015-04-01

    We report the production of an efficient anti-corrosive coating of cold-rolled (CR) steel in a seawater environment (~3.5 wt% NaCl aqueous solution) using an oil-based graphene oxide ink. The graphene oxide was produced by heating Aeschynomene aspera plant as a carbon source at 1600 °C in an argon atmosphere. The ink was prepared by cup-milling the mixture of graphene oxide and sunflower oil for 10 min. The coating of ink on the CR steel was made using the dip-coating method, followed by curing at 350 °C for 10 min in air atmosphere. The results of the potentiodynamic polarization show that the corrosion rate of bare CR steel decreases nearly 10 000-fold by the ink coating. Furthermore, the salt spray test results show that the red rusting in the ink-coated CR steel is initiated after 100 h, in contrast to 24 h and 6 h in the case of oil-coated and bare CR steel, respectively. The significant decrease in the corrosion rate by the ink-coating is discussed based on the impermeability of graphene oxide to the corrosive ions.We report the production of an efficient anti-corrosive coating of cold-rolled (CR) steel in a seawater environment (~3.5 wt% NaCl aqueous solution) using an oil-based graphene oxide ink. The graphene oxide was produced by heating Aeschynomene aspera plant as a carbon source at 1600 °C in an argon atmosphere. The ink was prepared by cup-milling the mixture of graphene oxide and sunflower oil for 10 min. The coating of ink on the CR steel was made using the dip-coating method, followed by curing at 350 °C for 10 min in air atmosphere. The results of the potentiodynamic polarization show that the corrosion rate of bare CR steel decreases nearly 10 000-fold by the ink coating. Furthermore, the salt spray test results show that the red rusting in the ink-coated CR steel is initiated after 100 h, in contrast to 24 h and 6 h in the case of oil-coated and bare CR steel, respectively. The significant decrease in the corrosion rate by the ink-coating is

  7. Aggression, Violence and Injury in Minor League Ice Hockey: Avenues for Prevention of Injury

    PubMed Central

    Cusimano, Michael D.; Ilie, Gabriela; Mullen, Sarah J.; Pauley, Christopher R.; Stulberg, Jennifer R.; Topolovec-Vranic, Jane; Zhang, Stanley

    2016-01-01

    Background In North America, more than 800,000 youth are registered in organized ice hockey leagues. Despite the many benefits of involvement, young players are at significant risk for injury. Body-checking and aggressive play are associated with high frequency of game-related injury including concussion. We conducted a qualitative study to understand why youth ice hockey players engage in aggressive, injury-prone behaviours on the ice. Methods Semi-structured interviews were conducted with 61 minor ice hockey participants, including male and female players, parents, coaches, trainers, managers and a game official. Players were aged 13–15 playing on competitive body checking teams or on non-body checking teams. Interviews were manually transcribed, coded and analyzed for themes relating to aggressive play in minor ice hockey. Results Parents, coaches, teammates and the media exert a large influence on player behavior. Aggressive behavior is often reinforced by the player’s social environment and justified by players to demonstrate loyalty to teammates and especially injured teammates by seeking revenge particularly in competitive, body-checking leagues. Among female and male players in non-body checking organizations, aggressive play is not reinforced by the social environment. These findings are discussed within the framework of social identity theory and social learning theory, in order to understand players’ need to seek revenge and how the social environment reinforces aggressive behaviors. Conclusion This study provides a better understanding of the players’ motivations and environmental influences around aggressive and violent play which may be conducive to injury. The findings can be used to help design interventions aimed at reducing aggression and related injuries sustained during ice hockey and sports with similar cultures and rules. PMID:27258426

  8. Desensitization to media violence: links with habitual media violence exposure, aggressive cognitions, and aggressive behavior.

    PubMed

    Krahé, Barbara; Möller, Ingrid; Huesmann, L Rowell; Kirwil, Lucyna; Felber, Juliane; Berger, Anja

    2011-04-01

    This study examined the links between desensitization to violent media stimuli and habitual media violence exposure as a predictor and aggressive cognitions and behavior as outcome variables. Two weeks after completing measures of habitual media violence exposure, trait aggression, trait arousability, and normative beliefs about aggression, undergraduates (N = 303) saw a violent film clip and a sad or a funny comparison clip. Skin conductance level (SCL) was measured continuously, and ratings of anxious and pleasant arousal were obtained after each clip. Following the clips, participants completed a lexical decision task to measure accessibility of aggressive cognitions and a competitive reaction time task to measure aggressive behavior. Habitual media violence exposure correlated negatively with SCL during violent clips and positively with pleasant arousal, response times for aggressive words, and trait aggression, but it was unrelated to anxious arousal and aggressive responding during the reaction time task. In path analyses controlling for trait aggression, normative beliefs, and trait arousability, habitual media violence exposure predicted faster accessibility of aggressive cognitions, partly mediated by higher pleasant arousal. Unprovoked aggression during the reaction time task was predicted by lower anxious arousal. Neither habitual media violence usage nor anxious or pleasant arousal predicted provoked aggression during the laboratory task, and SCL was unrelated to aggressive cognitions and behavior. No relations were found between habitual media violence viewing and arousal in response to the sad and funny film clips, and arousal in response to the sad and funny clips did not predict aggressive cognitions or aggressive behavior on the laboratory task. This suggests that the observed desensitization effects are specific to violent content. PMID:21186935

  9. Desensitization to Media Violence: Links With Habitual Media Violence Exposure, Aggressive Cognitions, and Aggressive Behavior

    PubMed Central

    Krahé, Barbara; Möller, Ingrid; Huesmann, L. Rowell; Kirwil, Lucyna; Felber, Juliane; Berger, Anja

    2015-01-01

    This study examined the links between desensitization to violent media stimuli and habitual media violence exposure as a predictor and aggressive cognitions and behavior as outcome variables. Two weeks after completing measures of habitual media violence exposure, trait aggression, trait arousability, and normative beliefs about aggression, undergraduates (N = 303) saw a violent film clip and a sad or a funny comparison clip. Skin conductance level (SCL) was measured continuously, and ratings of anxious and pleasant arousal were obtained after each clip. Following the clips, participants completed a lexical decision task to measure accessibility of aggressive cognitions and a competitive reaction time task to measure aggressive behavior. Habitual media violence exposure correlated negatively with SCL during violent clips and positively with pleasant arousal, response times for aggressive words, and trait aggression, but it was unrelated to anxious arousal and aggressive responding during the reaction time task. In path analyses controlling for trait aggression, normative beliefs, and trait arousability, habitual media violence exposure predicted faster accessibility of aggressive cognitions, partly mediated by higher pleasant arousal. Unprovoked aggression during the reaction time task was predicted by lower anxious arousal. Neither habitual media violence usage nor anxious or pleasant arousal predicted provoked aggression during the laboratory task, and SCL was unrelated to aggressive cognitions and behavior. No relations were found between habitual media violence viewing and arousal in response to the sad and funny film clips, and arousal in response to the sad and funny clips did not predict aggressive cognitions or aggressive behavior on the laboratory task. This suggests that the observed desensitization effects are specific to violent content. PMID:21186935

  10. Moral Judgments of Aggressive and Nonaggressive Children.

    ERIC Educational Resources Information Center

    Keltikangas-Jarvinen, Liisa

    1989-01-01

    Reports on a study of moral judgments in aggressive and nonaggressive children. Assessed moral judgment by presenting the children with stories of moral conflict in everyday life using peer rating. Results showed significant differences according to gender and no constant level of moral reasoning was measured in either aggressive or nonaggressive…

  11. Normative Beliefs Regarding Aggression in Emerging Adulthood

    ERIC Educational Resources Information Center

    Nelson, David A.; Springer, Melanie M.; Nelson, Larry J.; Bean, Nathaniel H.

    2008-01-01

    Few studies have examined the nature of aggression in emerging adulthood (ages 18-25), a unique developmental period wherein relationships become increasingly important and intimate. Consistent with a greater emphasis on relationships, relationally manipulative forms of aggression may be particularly salient during this time period. Based on…

  12. Students' Attitude to Aggression in School.

    ERIC Educational Resources Information Center

    Dettenborn, Harry; Lautsch, Erwin

    1994-01-01

    Reports on a study of 2,553 students' attitudes toward aggression in schools. Finds differentiated results based on demographic data and with the students' personal involvement in the aggressive acts as either the perpetrator or victim. Discusses practical consequences of the study for schools. (CFR)

  13. Aggressive and foraging behavioral interactions among ruffe

    USGS Publications Warehouse

    Savino, Jacqueline F.; Kostich, Melissa J.

    2000-01-01

    The ruffe, Gymnocephalus cernuus, is a nonindigenous percid in the Great Lakes. Ruffe are aggressive benthivores and forage over soft substrates. Laboratory studies in pools (100 cm in diameter, 15 cm water depth) were conducted to determine whether fish density (low = 2, medium = 4, high = 6 ruffe per pool) changed foraging and aggressive behaviors with a limited food supply of chironomid larvae. All fish densities demonstrated a hierarchy based on aggressive interactions, but ruffe were most aggressive at low and high fish densities. Time spent in foraging was lowest at the low fish density. The best forager at the low fish density was the most aggressive individual, but the second most aggressive fish at the medium and high fish density was the best forager and also the one chased most frequently. A medium fish density offered the best energetic benefits to ruffe by providing the lowest ratio of time spent in aggression to that spent foraging. Based on our results, ruffe should grow best at an intermediate density. With high ruffe densities, we would also expect disparity in size as the more aggressive fish are able to garner a disproportionate amount of the resources. Alternatively, as the Great Lakes are a fairly open system, ruffe could migrate out of one area to colonize another as populations exceed optimal densities.

  14. Forgivingness, anger, and hostility in aggressive driving.

    PubMed

    Kovácsová, Natália; Rošková, Eva; Lajunen, Timo

    2014-01-01

    This study was aimed at investigating the relationship between trait forgivingness, general anger, hostility, driving anger, and self-reported aggressive driving committed by the driver him/herself ("self" scale) and perceiving him/herself as an object of other drivers' aggressive acts ("other" scale). The Slovak version of questionnaires was administrated to a sample of 612 Slovak and Czech drivers. First, the factor structure of the Driver Anger Indicators Scale (DAIS) was investigated. Factor analyses of the self and other parts of the DAIS resulted in two factors, which were named as aggressive warnings and hostile aggression and revenge. Next, the results showed that from all dependent variables (scales of the DAIS), self-reported aggressive warnings (self) on the road were predicted best by chosen person-related factors. The path model for aggressive warnings (self) suggested that trait forgivingness and general anger were fully mediated by driving anger whereas hostility proved to be a unique predictor of aggressive behavior in traffic. Driving anger was found to be the best predictor of perceptions that other drivers behave aggressively. PMID:24211562

  15. School-Based Aggression Replacement Training

    ERIC Educational Resources Information Center

    Roth, Becky Sue; Striepling-Goldstein, Susan

    2003-01-01

    Aggression Replacement Training (ART) is a potent K-12 intervention that responds to many of the developmental and natural needs of aggressive and antisocial students. Woven into the curriculum preventatively or as a stand-alone course in response to an antisocial school climate, ART facilitates the learning necessary to reach and provide lasting…

  16. Pathways to Aggression in Children and Adolescents

    ERIC Educational Resources Information Center

    Watson, Malcolm W.; Fischer, Kurt W.; Andreas, Jasmina Burdzovic; Smith, Kevin W.

    2004-01-01

    In this article, Malcolm Watson, Kurt Fischer, Jasmina Burdzovic Andreas, and Kevin Smith describe and compare two approaches to assessing risk factors that lead to aggression in children. The first, the severe risks approach, focuses on how risk factors form a pathway that leads to aggressive behavior. Within this approach, an inhibited…

  17. Involvement in Internet Aggression during Early Adolescence

    ERIC Educational Resources Information Center

    Werner, Nicole E.; Bumpus, Matthew F.; Rock, Daquarii

    2010-01-01

    The current study examined concurrent and longitudinal predictors of early adolescents' involvement in Internet aggression. Cross-sectional results (N = 330; 57% female) showed that the likelihood of reporting Internet aggression was higher among youth who spent more time using Internet-based technologies to communicate with friends and who were…

  18. Relational Aggression and Victimization in College Students

    ERIC Educational Resources Information Center

    Dahlen, Eric R.; Czar, Katherine A.; Prather, Emily; Dyess, Christy

    2013-01-01

    For this study we explored relational aggression and victimization in a college sample (N = 307), examining potential gender and race differences, correlates, and the link between relational aggression and common emotional and behavioral problems, independent of relational victimization. Gender and race differences were observed on relational…

  19. The Barrier within: Relational Aggression among Women

    ERIC Educational Resources Information Center

    Brock, Barbara L.

    2010-01-01

    Relational aggression among women presents an overlooked barrier to women's quest for advancement in the workplace. Although research on women's leadership extols their ability to collaborate and form lasting, supportive relationships, one cannot assume that all women are supportive of other women. Research reveals that relational aggression,…

  20. How Food Controls Aggression in Drosophila

    PubMed Central

    Lim, Rod S.; Eyjólfsdóttir, Eyrún; Shin, Euncheol; Perona, Pietro; Anderson, David J.

    2014-01-01

    How animals use sensory information to weigh the risks vs. benefits of behavioral decisions remains poorly understood. Inter-male aggression is triggered when animals perceive both the presence of an appetitive resource, such as food or females, and of competing conspecific males. How such signals are detected and integrated to control the decision to fight is not clear. For instance, it is unclear whether food increases aggression directly, or as a secondary consequence of increased social interactions caused by attraction to food. Here we use the vinegar fly, Drosophila melanogaster, to investigate the manner by which food influences aggression. We show that food promotes aggression in flies, and that it does so independently of any effect on frequency of contact between males, increase in locomotor activity or general enhancement of social interactions. Importantly, the level of aggression depends on the absolute amount of food, rather than on its surface area or concentration. When food resources exceed a certain level, aggression is diminished, suggestive of reduced competition. Finally, we show that detection of sugar via Gr5a+ gustatory receptor neurons (GRNs) is necessary for food-promoted aggression. These data demonstrate that food exerts a specific effect to promote aggression in male flies, and that this effect is mediated, at least in part, by sweet-sensing GRNs. PMID:25162609

  1. The Prevention of Social Aggression among Girls

    ERIC Educational Resources Information Center

    Cappella, Elise; Weinstein, Rhona

    2006-01-01

    This study represents the first systematic attempt to examine a theory-based program designed to reduce girls' social aggression and increase positive leadership among peers. Fifth-grade girls from six public schools were randomly assigned within classrooms to the social aggression prevention program (SAPP) and the comparison reading clubs. A…

  2. Understanding Aggressive Behavior Across the Life Span

    PubMed Central

    Liu, Jianghong; Lewis, Gary; Evans, Lois

    2012-01-01

    Aggressive behavior is the observable manifestation of aggression and is often associated with developmental transitions and a range of medical and psychiatric diagnoses across the lifespan. As healthcare professionals involved in the medical and psychosocial care of patients from birth through death, nurses frequently encounter—and may serve as—both victims and perpetrators of aggressive behavior in the workplace. While the nursing literature has continually reported research on prevention and treatment approaches, less emphasis has been given to understanding the etiology, including contextual precipitants of aggressive behavior. This paper provides a brief review of the biological, social, and environmental risk factors that purportedly give rise to aggressive behavior. Further, many researchers have focused specifically on aggressive behavior in adolescence and adulthood. Less attention has been given to understanding the etiology of such behavior in young children and older adults. This paper emphasizes the unique risk factors for aggressive behavior across the developmental spectrum, including childhood, adolescence, adulthood, and late life. Appreciation of the risk factors of aggressive behavior, and, in particular, how they relate to age-specific manifestations, can aid nurses in better design and implementation of prevention and treatment programs. PMID:22471771

  3. Intercommunity differences in aggression among Zapotec children.

    PubMed

    Fry, D P

    1988-08-01

    Patterns of play aggression and serious aggression were compared in 2 neighboring Zapotec Indian communities that have different levels of adult violence. Social learning theory provided the basis for predicting that levels of agonistic behavior among children would parallel levels of violence among adults. Ethological methods were employed to observe 3-8-year-old children (N = 48). An examination of physical aggression and nonphysical threatening showed that agonism generally was more severe among the children of the more aggressive community. That is, children from the more aggressive community engaged in more actual fighting (p = .005) and play fighting (p = .0001) than their counterparts from the other community. On the other hand, children from the less aggressive community used more noncontact threatening than the children from the more aggressive community (p = .0001). These findings suggest that community differences in levels of violence are perpetuated as Zapotec children learn community-appropriate patterns for expressing aggression and continue to express these patterns as adults. Possible functions of play fighting are also discussed. PMID:3168610

  4. Parental Behavior, TV Habits, IQ Predict Aggression.

    ERIC Educational Resources Information Center

    Greenberg, J.

    1983-01-01

    Highlights a longitudinal study on key factors in the metamorphosis of childhood aggression into adult crime in more than 400 males/females. Results (which began with study of 875 third graders in 1960) indicate that aggressive youngsters at age eight have much higher rates of criminal/violent behavior at age 30. (JN)

  5. Influence of oxidation states on plutonium mobility during long-term transport through an unsaturated subsurface environment.

    PubMed

    Kaplan, Daniel I; Powell, Brian A; Demirkanli, Deniz I; Fjeld, Robert A; Molz, Fred J; Serkiz, Steven M; Coates, John T

    2004-10-01

    Lysimeter and laboratory studies were conducted to identify the controlling chemical processes influencing Pu(IV) mobility through the vadose zone. A 52-L lysimeter containing sediment from the Savannah River Site, South Carolina and solid PuIV(NO3)4 was left exposed to natural wetting and drying cycles for 11 years before the lysimeter sediment was sampled. Pu had traveled 10 cm, with >95% of the Pu remaining within 1.25 cm of the source. Laboratory studies showed that the sediment quickly reduced Pu(V) to Pu(IV) (the pseudo-first-order reduction rate constant, Kobs, was 0.11 h(-1)). Of particular interest was that this same sediment could be induced to release very low concentrations of sorbed Pu under oxidizing conditions, presumably by oxidation of sorbed Pu(IV) to the more mobile Pu(V) species. Transport modeling supported the postulation that Pu oxidation occurred in the lysimeter sediment; the inclusion of an oxidation term in the model produced simulations that capture the Pu depth profile data. By not including the oxidation process in the model, Pu mobility was grossly underestimated by a factor of 3.5. It is concluded that both oxidation and reduction mechanisms can play an important role in Pu transportthrough the vadose zone and should be considered when evaluating disposal of Pu-bearing wastes. PMID:15506198

  6. Inter- and intraspecific aggression in the invasive longlegged ant (Hymenoptera: Formicidae).

    PubMed

    Chong, Kim-Fung; Lee, Chow-Yang

    2010-10-01

    The longlegged ant, Anoplolepis gracilipes (Fr. Smith) (Hymenoptera: Formicidae), is a highly invasive species that can aggressively displace other ant species. We conducted laboratory assays to examine interspecies aggression of A. gracilipes versus 15 sympatric ant species found in the urban environment and disturbed habitat in Malaysia: Monomorium pharaonis (L.), Monomorium floricola (Jerdon), Monomorium orientale Mayr, Monomorium destructor (Jerdon), Pheidole parva Mayr, Crematogaster sp., Solenopsis geminata (F.), Tapinoma indicum (Forel), Tapinoma melanocephalum (F.), Technomyrmnex butteli Forel, Dolichoderus thoracicus (Smith), Paratrechina longicornis (Latrielle), Oecophylla smaragdina (F), Camponotus sp., and Tetraponera rufonigra (Jerdon). A. gracilipes showed aggressive behavior toward all opponent species, except the smallest M. orientale. Opponent species size (body size, head width, and mandible width) was significantly correlated with A. gracilipes aggression level and mortality rate. We also found a significant positive relationship between A. gracilipes aggression level and the mortality of the opponent species. The results suggest that invasive populations of A. gracilipes would have the greatest impact on larger ant species. In addition, we examined the intraspecific aggression of A. gracilipes. We found that A. gracilipes from different localities in Malaysia showed intraspecific aggression toward one another. This finding differs from the results of studies conducted in Christmas Island earlier. Differences in the genetic variability among populations may explain these differing results. PMID:21061979

  7. Relationships of smiling and flirtation to aggression and 2D:4D, a prenatal androgen index.

    PubMed

    Burton, Leslie; Bolt, Nicholas; Hadjikyriacou, Despina; Silton, Nava; Kilgallen, Christine; Allimant, Janaina

    2011-01-01

    Smiling has been reported to be a signal of submission/lower status, or a sign of cooperation. In the present study, use of smiling and flirtation to "make people receptive to my ideas" was conceptualized as mild aggression, since it is mildly manipulative of the perception of others as to one's internal emotional status. For 91 participants (55 female, 36 male), use of smiling and flirtation to make others receptive to one's ideas were associated with relational aggression and a more male-typical (smaller) right 2D:4D finger length ratio. The only significant relationship in the male sample alone was the relationship between smiling and relational aggression. In the female sample alone, use of smiling and flirtation to "make people receptive to my ideas" was associated with a more male-typical 2D:4D finger length ratio pattern, and there was a trend for flirtation to be associated with greater physical aggression. Both 2D:4D and physical aggression have been associated with higher prenatal androgen level. It is concluded that deliberate smiling and flirtation are mild forms of relational aggression, and are related to prenatal androgenic activity in a manner similar to physical aggression. These findings are discussed in terms of the different evolutionary strategies of men and women to control their social environments. PMID:22947951

  8. The association between forms of aggression, leadership, and social status among urban youth.

    PubMed

    Waasdorp, Tracy Evian; Baker, Courtney N; Paskewich, Brooke S; Leff, Stephen S

    2013-02-01

    While much prior research has documented the negative associations between aggression, peer relationships, and social skills, other research has begun to examine whether forms of aggression also may be associated with prosocial skills and increased social status. However, few studies have examined these associations within diverse samples of elementary aged youth. The current study examined the associations between aggression, popularity, social preference, and leadership among 227 urban, ethnic minority (74 % African American, 9 % bi-racial including African American, 12 % other ethnic minorities, and 5 % European American) elementary school youth (average age 9.5 years, 48.5 % female). Results indicated that in an urban, high risk environment, displaying aggressive behaviors was associated with increased perceived popularity, decreased social preference, and, in some cases, increased perceived leadership. The results also suggested gender differences in the association between the forms of aggression (i.e. relational and overt) and popularity. The current study underscores the importance of examining youth leadership along with forms of aggression and social status among urban minority youth. Implications for future research and aggression prevention programming are highlighted. PMID:23086015

  9. Trajectories of Adolescent Aggression and Family Cohesion: The Potential to Perpetuate or Ameliorate Political Conflict.

    PubMed

    Taylor, Laura K; Merrilees, Christine E; Goeke-Morey, Marcie C; Shirlow, Pete; Cummings, E Mark

    2016-01-01

    Correlations between intergroup violence and youth aggression are often reported. Yet longitudinal research is needed to understand the developmental factors underlying this relation, including between-person differences in within-person change in aggression through the adolescent years. Multilevel modeling was used to explore developmental and contextual influences related to risk for youth aggression using 4 waves of a prospective, longitudinal study of adolescent/mother dyad reports (N = 820; 51% female; 10-20 years old) in Belfast, Northern Ireland, a setting of protracted political conflict. Experience with sectarian (i.e., intergroup) antisocial behavior predicted greater youth aggression; however, that effect declined with age, and youth were buffered by a cohesive family environment. The trajectory of aggression (i.e., intercepts and linear slopes) related to more youth engagement in sectarian antisocial behavior; however, being female and having a more cohesive family were associated with lower levels of youth participation in sectarian acts. The findings are discussed in terms of protective and risk factors for adolescent aggression, and more specifically, participation in sectarian antisocial behavior. The article concludes with clinical and intervention implications, which may decrease youth aggression and the perpetuation of intergroup violence in contexts of ongoing conflict. PMID:25310245

  10. Bullying: a stepping stone to dating aggression?

    PubMed

    Josephson, Wendy L; Pepler, Debra

    2012-01-01

    Bullying is the use of power and aggression to control and distress another. In this paper, we review research to explore whether the lessons learned in bullying provide a stepping stone to aggressive behavior in dating relationships. We start by considering definitions and a relationship framework with which to understand both bullying and dating aggression. We consider bullying from a developmental-contextual perspective and consider risk factors associated with the typical developmental patterns for bullying and dating aggression, including developmental and sociodemographic, individual attributes, and family, peer group, community, and societal relationship contexts that might lead some children and youths to follow developmental pathways that lead to bullying and dating aggression. We conclude by discussing implications for intervention with a review of evidence-based interventions. PMID:22909910

  11. Products of the radical initiated oxidation of model solid and liquid organic acid particles in simulated "clean" and "polluted" environments.

    NASA Astrophysics Data System (ADS)

    Renbaum, L. H.; Smith, G. D.

    2009-05-01

    Using a flow tube reactor coupled to a chemical ionization mass spectrometer, the Cl-initiated oxidation of solid and supercooled liquid organic acid particles were investigated at 293 K. In creating aerosols of species which are able to be supercooled or solid at room temperature, it is possible to distinguish the effect of phase on particle reactivity and product formation. In a clean atmosphere, where there are negligible concentrations of NOx, the primary fate of peroxy radicals (formed from H-abstraction by Cl and OH radicals in the presence of O2) are their reactions to form ketone and alcohol products. These products are then able to undergo further oxidation to form multiply oxidized products. The formation of low-molecular weight volatile species may also be important in the oxidative aging of organic aerosols, however neither the mechanism of their formation nor their formation yields are well understood. We have shown that, for equivalent Cl exposures, more multiply-oxidized species as well as more low-molecular-weight species were created from the oxidation of solid particles than from liquid particles. The findings from these studies suggest that slower diffusion of the oxidation products in solid particles confines them to the surface where they continue to react with Cl radicals producing more-highly- functionalized products which may decompose more readily. By introducing nitric oxide to the flow tube reaction system, we show that in a polluted atmosphere, where NOx is present in significant concentrations, organic nitrate formation may become important on the surface of solid particles but not liquid particles as the RO2 are confined to the surface of solid particles (causing a enhanced localized concentration of RO2) where they may then react with ambient nitric oxide through the reaction RO2 + NO → RO2NO* → RONO2. These experiments of these model systems indicate that particle phase could be important in determining how organic aerosols

  12. Evaluation of oxide-coated iridium-rhenium chambers

    NASA Technical Reports Server (NTRS)

    Reed, Brian D.

    1994-01-01

    Iridium-coated rhenium (Ir-Re) provides long life operation of radiation-cooled rockets at temperatures up to 2200 C. Ceramic oxide coatings could be used to increase Ir-Re rocket lifetimes and allow operation in highly oxidizing environments. Ceramic oxide coatings promise to serve as both thermal and diffusion barriers for the iridium layer. Seven ceramic oxide-coated Ir-Re, 22-N rocket chambers were tested with gaseous hydrogen/gaseous oxygen (GHz/G02) propellants. Five chambers had thick (over 10 mils), monolithic coatings of either hafnia (HfO2) or zirconia (ZrO2). Two chambers had coatings with thicknesses less than 5 mils. One of these chambers had a thin-walled coating of ZrO2 infiltrated with sol gel HfO2. The other chamber had a coating composed of an Ir-oxide composite. The purpose of this test program was to assess the ability of the oxide coatings to withstand the thermal shock of combustion initiation, adhere under repeated thermal cycling, and operate in aggressively oxidizing environments. All of the coatings survived the thermal shock of combustion and demonstrated operation at mixture ratios up to 11. Testing the Ir-oxide composite-coated chamber included over 29 min at mixture ratio 16. The thicker walled coatings provided the larger temperature drops across the oxide layer (up to 570 C), but were susceptible to macrocracking and eventual chipping at a stress concentrator. The cracks apparently resealed during firing, under compression of the oxide layer. The thinner walled coatings did not experience the macrocracking and chipping of the chambers that was seen with the thick, monolithic coatings. However, burn-throughs in the throat region did occur in both of the thin-walled chambers at mixture ratios well above stoichiometric. The burn-throughs were probably the result of oxygen diffusion through the oxide coating that allowed the underlying Ir and Re layers to be oxidized. The results of this test program indicated that the thin-walled oxide

  13. Evaluation of oxide-coated iridium-rhenium chambers

    NASA Astrophysics Data System (ADS)

    Reed, Brian D.

    1994-03-01

    Iridium-coated rhenium (Ir-Re) provides long life operation of radiation-cooled rockets at temperatures up to 2200 C. Ceramic oxide coatings could be used to increase Ir-Re rocket lifetimes and allow operation in highly oxidizing environments. Ceramic oxide coatings promise to serve as both thermal and diffusion barriers for the iridium layer. Seven ceramic oxide-coated Ir-Re, 22-N rocket chambers were tested with gaseous hydrogen/gaseous oxygen (GHz/G02) propellants. Five chambers had thick (over 10 mils), monolithic coatings of either hafnia (HfO2) or zirconia (ZrO2). Two chambers had coatings with thicknesses less than 5 mils. One of these chambers had a thin-walled coating of ZrO2 infiltrated with sol gel HfO2. The other chamber had a coating composed of an Ir-oxide composite. The purpose of this test program was to assess the ability of the oxide coatings to withstand the thermal shock of combustion initiation, adhere under repeated thermal cycling, and operate in aggressively oxidizing environments. All of the coatings survived the thermal shock of combustion and demonstrated operation at mixture ratios up to 11. Testing the Ir-oxide composite-coated chamber included over 29 min at mixture ratio 16. The thicker walled coatings provided the larger temperature drops across the oxide layer (up to 570 C), but were susceptible to macrocracking and eventual chipping at a stress concentrator. The cracks apparently resealed during firing, under compression of the oxide layer. The thinner walled coatings did not experience the macrocracking and chipping of the chambers that was seen with the thick, monolithic coatings. However, burn-throughs in the throat region did occur in both of the thin-walled chambers at mixture ratios well above stoichiometric. The burn-throughs were probably the result of oxygen diffusion through the oxide coating that allowed the underlying Ir and Re layers to be oxidized. The results of this test program indicated that the thin-walled oxide

  14. When do normative beliefs about aggression predict aggressive behavior? An application of I3 theory.

    PubMed

    Li, Jian-Bin; Nie, Yan-Gang; Boardley, Ian D; Dou, Kai; Situ, Qiao-Min

    2015-01-01

    I(3) theory assumes that aggressive behavior is dependent on three orthogonal processes (i.e., Instigator, Impellance, and Inhibition). Previous studies showed that Impellance (trait aggressiveness, retaliation tendencies) better predicted aggression when Instigator was strong and Inhibition was weak. In the current study, we predicted that another Impellance (i.e., normative beliefs about aggression) might predict aggression when Instigator was absent and Inhibition was high (i.e., the perfect calm proposition). In two experiments, participants first completed the normative beliefs about aggression questionnaire. Two weeks later, participants' self-control resources were manipulated either using the Stroop task (study 1, N = 148) or through an "e-crossing" task (study 2, N = 180). Afterwards, with or without being provoked, participants played a game with an ostensible partner where they had a chance to aggress against them. Study 1 found that normative beliefs about aggression negatively and significantly predicted aggressive behavior only when provocation was absent and self-control resources were not depleted. In Study 2, normative beliefs about aggression negatively predicted aggressive behavior at marginal significance level only in the "no-provocation and no-depletion" condition. In conclusion, the current study provides partial support for the perfect calm proposition and I(3) theory. PMID:26075351

  15. The importance of narcissism in predicting proactive and reactive aggression in moderately to highly aggressive children.

    PubMed

    Barry, Tammy D; Thompson, Alice; Barry, Christopher T; Lochman, John E; Adler, Kristy; Hill, Kwoneathia

    2007-01-01

    The present study examined the importance of psychopathy-linked narcissism in predicting proactive and reactive aggression and conduct problems in a group of 160 moderately to highly aggressive children (mean age of 10 years, 9 months). Children's self-report of self-esteem and parent and teacher report of dimensions of psychopathy [narcissism, callous-unemotional (CU) traits, and impulsivity], proactive and reactive aggression, and conduct problems were collected. Composites of parent and teacher ratings of children's behavior were used. Consistent with the study's hypotheses, narcissism predicted unique variance in both proactive and reactive aggression, even when controlling for other dimensions of psychopathy, demographic variables associated with narcissism, and the alternative subtype of aggression. As hypothesized, impulsivity was significantly associated with only reactive aggression. CU traits were not related to proactive or reactive aggression once the control variables were entered. All dimensions of psychopathy predicted unique variance in conduct problems. Consistent with prediction, narcissism was not significantly related to general self-esteem, providing support that narcissism and self-esteem are different constructs. Furthermore, narcissism and self-esteem related differentially to proactive aggression, reactive aggression, and conduct problems. Furthermore, narcissism but not self-esteem accounted for unique variance in aggression and conduct problems. The importance of narcissism in the prediction of aggressive behaviors and clinical implications are discussed. PMID:17444525

  16. Not all aggressions are created equal: a multifoci approach to workplace aggression.

    PubMed

    Chang, Chu-Hsiang Daisy; Lyons, Brent J

    2012-01-01

    Types of perpetrators of workplace aggression can vary considerably, and recent research has demonstrated that aggression from different perpetrator categories has different implications for victims. We extended research on multifoci aggression and explored affective and cognitive pathways linking verbal aggression from four perpetrator types--supervisors, coworkers, customers, and significant others--and employee morale and turnover intention. Data from a sample of 446 working adults indicated that both emotional strain and employees' corresponding judgments of their social exchange relationships with these perpetrators served as the mechanisms for the association between aggression from supervisors, coworkers, and customers and morale and turnover intention. Coworker aggression had a direct association with turnover intention and significant other aggression was related to turnover intention only through emotional strain. The theoretical and practical implications of these findings are discussed. PMID:22122549

  17. The relationships among perceived peer acceptance of sexual aggression, punishment certainty, and sexually aggressive behavior.

    PubMed

    Strang, Emily; Peterson, Zoë D

    2013-12-01

    Researching the correlates of men's sexually aggressive behavior (i.e., verbal coercion and rape) is critical to both understanding and preventing sexual aggression. This study examined 120 men who completed an anonymous online questionnaire. The study aimed to determine the relative importance of two potential correlates of men's self-reported use of sexual aggression: (a) perceptions that male peers use and support sexual aggression and (b) perceptions of punishment likelihood associated with sexual aggression. Results revealed that perceptions of male friends' acceptance of sexual aggression were strongly associated with individual men's reports of using verbal coercion and rape. Perceptions of punishment likelihood were negatively correlated with verbal coercion but not with rape through intoxication and force. Implications for sexual aggression prevention are discussed. PMID:24014542

  18. The Influence of Classroom Aggression and Classroom Climate on Aggressive-Disruptive Behavior

    PubMed Central

    Thomas, Duane E.; Bierman, Karen L.; Powers, CJ

    2011-01-01

    Research suggests that early classroom experiences influence the socialization of aggression. Tracking changes in the aggressive behavior of 4179 children from kindergarten to second-grade (ages 5–8) this study examined the impact of two important features of the classroom context–aggregate peer aggression and climates characterized by supportive teacher-student interactions. The aggregate aggression scores of children assigned to first-grade classrooms predicted the level of classroom aggression (assessed by teacher ratings) and quality of classroom climate (assessed by observers) that emerged by the end of grade 1. HLM analyses revealed that first-grade classroom aggression and quality of classroom climate made independent contributions to changes in student aggression, as students moved from kindergarten to second grade. Implications for policy and practice are discussed. PMID:21434887

  19. CHARACTERIZATION OF TORSO SIDE AIRBAG AGGRESSIVITY

    PubMed Central

    Hallman, Jason J.; Yoganandan, Narayan; Pintar, Frank A.

    2009-01-01

    Torso side airbags are typically seat- or door-mounted; i.e., mounted within the seat back or within the door panel lateral to the occupant. Because previous work has shown the propensity of airbags to cause harm in unintended out-of-position occupant orientations, scientific investigation of injury risks continues. Such work involves anthropomorphic test devices and cadaveric specimens which have time and monetary costs associated with their use. These costs necessitate experimental efficiency, achieved by selecting representative airbags from the multitude of options in contemporary automobiles. This study proposes a novel method for characterizing torso side airbag deployment aggressivity for purposes of selection. The test fixture consisted of an array of rigidly positioned three-axis load cells oriented in opposition to a rigid airbag mount at fixed distances of 6 or 8 cm. Six exemplar torso airbag modules were subjected to these two deployment configurations. Force characteristics of maximum resultant force, peak and mean force onset rate, and linear impulse were quantified for comparison. Force characteristics demonstrated ranges between 210% (linear impulse) and 2,500% (mean force onset rate) of minimum value. This test method demonstrated differentiation in the diversity of SAB designs and quantified the airbag-environment interaction during deployment. These force characteristics may correlate to thoracic injury risk from out-of-position torso side airbag deployment. PMID:19369747

  20. Aggression on inpatient units: Clinical characteristics and consequences.

    PubMed

    Renwick, Laoise; Stewart, Duncan; Richardson, Michelle; Lavelle, Mary; James, Karen; Hardy, Claire; Price, Owen; Bowers, Len

    2016-08-01

    Aggression and violence are widespread in UK Mental Health Trusts, and are accompanied by negative psychological and physiological consequences for both staff and other patients. Patients who are younger, male, and have a history of substance use and psychosis diagnoses are more likely to display aggression; however, patient factors are not solely responsible for violence, and there are complex circumstances that lead to aggression. Indeed, patient-staff interactions lead to a sizeable portion of aggression and violence on inpatient units, thus they cannot be viewed without considering other forms of conflict and containment that occur before, during, and after the aggressive incident. For this reason, we examined sequences of aggressive incidents in conjunction with other conflict and containment methods used to explore whether there were particular profiles to aggressive incidents. In the present study, 522 adult psychiatric inpatients from 84 acute wards were recruited, and there were 1422 incidents of aggression (verbal, physical against objects, and physical). Cluster analysis revealed that aggressive incident sequences could be classified into four separate groups: solo aggression, aggression-rule breaking, aggression-medication, and aggression-containment. Contrary to our expectations, we did not find physical aggression dominant in the aggression-containment cluster, and while verbal aggression occurred primarily in solo aggression, physical aggression also occurred here. This indicates that the management of aggression is variable, and although some patient factors are linked with different clusters, these do not entirely explain the variation. PMID:26892149

  1. Ceriodaphnia dubia as a Potential Bio-Indicator for Assessing Acute Aluminum Oxide Nanoparticle Toxicity in Fresh Water Environment

    PubMed Central

    Pakrashi, Sunandan; Dalai, Swayamprava; Humayun, Ahmed; Chakravarty, Sujay; Chandrasekaran, Natarajan; Mukherjee, Amitava

    2013-01-01

    Growing nanomaterials based consumer applications have raised concerns about their potential release into the aquatic ecosystems and the consequent toxicological impacts. So environmental monitoring of the nanomaterials in aqueous systems becomes imperative. The current study reveals the potential of Ceriodaphnia dubia (C. dubia) as a bio-indicator for aluminum oxide nanoparticles in a fresh water aquatic ecosystem where it occupies an important ecological niche as a primary consumer. This study aims to investigate the aluminium oxide nanoparticle induced acute toxicity on Ceriodaphnia dubia in a freshwater system. The bioavailability of the aluminum oxide nanoparticles has been studied with respect to their aggregation behavior in the system and correlated with the toxicity endpoints. The oxidative stress generated by the particles contributed greatly toward their toxicity. The crucial role of leached aluminium ion mediated toxicity in the later phases (48 h and 72 h) in conjunction with the effects from the nano-sized particles in the initial phases (24 h) puts forth the dynamics of nanotoxicity in the test system. The internalization of nanoparticles (both gross and systemic uptake) as substantiated through the transmission electron microscopy (TEM) and inductively coupled plasma optical emission spectral (ICP-OES) analysis was another major contributor toward acute toxicity. Concluding the present study, Ceriodaphnia dubia can be a promising candidate for bio-monitoring the aluminium oxide nanoparticles in a fresh water system. PMID:24040143

  2. IMP2/p62 induces genomic instability and an aggressive hepatocellular carcinoma phenotype.

    PubMed

    Kessler, S M; Laggai, S; Barghash, A; Schultheiss, C S; Lederer, E; Artl, M; Helms, V; Haybaeck, J; Kiemer, A K

    2015-01-01

    Hepatocellular carcinoma (HCC) represents the third leading cause of cancer-related deaths and commonly develops in inflammatory environments. The IGF2 mRNA-binding protein IMP2-2/IGF2BP2-2/p62 was originally identified as an autoantigen in HCC. Aim of this study was to investigate a potential pathophysiological role of p62 in hepatocarcinogenesis. Human HCC tissue showed overexpression of IMP2, which strongly correlated with the fetal markers AFP and DLK1/Pref-1/FA-1 and was particularly elevated in tumors with stem-like features and hypervascularization. Molecular classification of IMP2-overexpressing tumors revealed an aggressive phenotype. Livers of mice overexpressing the IMP2 splice variant p62 highly expressed the stem cell marker DLK1 and secreted DLK1 into the blood. p62 was oncogenic: diethylnitrosamine (DEN)-treated p62 transgenic mice exhibited a higher tumor incidence and multiplicity than wild types. Tumors of transgenics showed a more aggressive and stem-like phenotype and displayed more oncogenic chromosomal aberrations determined with aCGH analysis. DEN-treated p62 transgenic mice exhibited distinct signs of inflammation, such as inflammatory cytokine expression and oxidative stress markers, that is, thiobarbituric acid-reactive substance (TBARS) levels. Reactive oxygen species (ROS) production was elevated in HepG2 cells, which either overexpressed p62 or were treated with DLK1. p62 induced this ROS production by a DLK1-dependent induction and activation of the small Rho-GTPase RAC1, activating NADPH oxidase and being overexpressed in human HCC. Our data indicate that p62/IMP2 promotes hepatocarcinogenesis by an amplification of inflammation. PMID:26426686

  3. IMP2/p62 induces genomic instability and an aggressive hepatocellular carcinoma phenotype

    PubMed Central

    Kessler, S M; Laggai, S; Barghash, A; Schultheiss, C S; Lederer, E; Artl, M; Helms, V; Haybaeck, J; Kiemer, A K

    2015-01-01

    Hepatocellular carcinoma (HCC) represents the third leading cause of cancer-related deaths and commonly develops in inflammatory environments. The IGF2 mRNA-binding protein IMP2-2/IGF2BP2-2/p62 was originally identified as an autoantigen in HCC. Aim of this study was to investigate a potential pathophysiological role of p62 in hepatocarcinogenesis. Human HCC tissue showed overexpression of IMP2, which strongly correlated with the fetal markers AFP and DLK1/Pref-1/FA-1 and was particularly elevated in tumors with stem-like features and hypervascularization. Molecular classification of IMP2-overexpressing tumors revealed an aggressive phenotype. Livers of mice overexpressing the IMP2 splice variant p62 highly expressed the stem cell marker DLK1 and secreted DLK1 into the blood. p62 was oncogenic: diethylnitrosamine (DEN)-treated p62 transgenic mice exhibited a higher tumor incidence and multiplicity than wild types. Tumors of transgenics showed a more aggressive and stem-like phenotype and displayed more oncogenic chromosomal aberrations determined with aCGH analysis. DEN-treated p62 transgenic mice exhibited distinct signs of inflammation, such as inflammatory cytokine expression and oxidative stress markers, that is, thiobarbituric acid-reactive substance (TBARS) levels. Reactive oxygen species (ROS) production was elevated in HepG2 cells, which either overexpressed p62 or were treated with DLK1. p62 induced this ROS production by a DLK1-dependent induction and activation of the small Rho-GTPase RAC1, activating NADPH oxidase and being overexpressed in human HCC. Our data indicate that p62/IMP2 promotes hepatocarcinogenesis by an amplification of inflammation. PMID:26426686

  4. Timing of presentation of an audience: aggressive priming and audience effects in male displays of Siamese fighting fish (Betta splendens).

    PubMed

    Matos, Ricardo J.; Peake, Tom M.; McGregor, Peter K.

    2003-05-28

    Studies of animal communication often underestimate the presence of individuals other than the signaller-receiver dyad. Signalling interactions often occur in the presence of non-participating individuals (audiences); the effect of these individuals upon the dynamics of interactions has been called the audience effect. Recent studies of fighting fish Betta splendens have shown that the presence of a male audience can increase aggression during interactions. However, in many of these studies males were allowed to see the audience prior to the interaction, thus such pre-exposure may have facilitated aggressive behaviour (aggressive priming). Here we present results of two experiments designed to examine the relative importance of priming and audience effects on the dynamics of aggressive interactions. Males that were pre-exposed showed higher levels of aggression during subsequent interactions regardless of the presence or absence of an audience. When only one of the interactants had been pre-exposed to the audience, the non-exposed male showed similar increases in aggressive behaviour, i.e. matching the level of aggression showed by his opponent. Taken together these results suggest that aggressive priming may have resulted in an over-estimation of the audience effect in previous studies. The results still highlight the importance of social environment in determining the dynamics and outcomes of aggressive contests. PMID:12763268

  5. Efficient anti-corrosive coating of cold-rolled steel in a seawater environment using an oil-based graphene oxide ink.

    PubMed

    Singhbabu, Y N; Sivakumar, B; Singh, J K; Bapari, H; Pramanick, A K; Sahu, Ranjan K

    2015-05-01

    We report the production of an efficient anti-corrosive coating of cold-rolled (CR) steel in a seawater environment (∼3.5 wt% NaCl aqueous solution) using an oil-based graphene oxide ink. The graphene oxide was produced by heating Aeschynomene aspera plant as a carbon source at 1600 °C in an argon atmosphere. The ink was prepared by cup-milling the mixture of graphene oxide and sunflower oil for 10 min. The coating of ink on the CR steel was made using the dip-coating method, followed by curing at 350 °C for 10 min in air atmosphere. The results of the potentiodynamic polarization show that the corrosion rate of bare CR steel decreases nearly 10,000-fold by the ink coating. Furthermore, the salt spray test results show that the red rusting in the ink-coated CR steel is initiated after 100 h, in contrast to 24 h and 6 h in the case of oil-coated and bare CR steel, respectively. The significant decrease in the corrosion rate by the ink-coating is discussed based on the impermeability of graphene oxide to the corrosive ions. PMID:25869204

  6. Behavioural Indicators of Motives for Barroom Aggression: Implications for Preventing Bar Violence

    PubMed Central

    Graham, Kathryn; Bernards, Sharon; Wells, Samantha; Osgood, D. Wayne; Abbey, Antonia; Felson, Richard B.; Saltz, Robert F.

    2010-01-01

    Introduction/Aims To develop new strategies for preventing violence in high risk licensed premises, we identify behavioural indicators of apparent motives for aggression in these settings and outline the implications of different motivation for prevention. Design/Methods The four types of motives for aggressive or coercive acts defined by the theory of coercive actions framed the research: gaining compliance, expressing grievances/restoring justice, attaining a favourable social identity, and pursuing fun/excitement. Incidents of aggression from the Safer Bars evaluation research [1] were analysed to identify behavioural indicators of each motivation. Results Compliance-motivated aggression typically takes the form of unwanted social overtures, third party intervention to stop conflicts or staff rule enforcement. Prevention strategies include keeping the aggressor’s focus on compliance to avoid provoking grievance and identity motives which are likely to escalate aggression. Grievance motives are typically elicited by perceived wrongdoing and, therefore, prevention should focus on eliminating sources of grievances and adopting policies/practices to resolve grievances peacefully. Social identity motives are endemic to many drinking establishments especially among male patrons and staff. Prevention involves reducing identity cues in the environment, hiring staff who do not have identity concerns, and training staff to avoid provoking identity concerns. Aggression motivated by fun/excitement often involves low-level aggression where escalation can be prevented by avoiding grievances and attacks on identity. Discussion/Conclusions Knowledge of behavioural indicators of motives can be used to enhance staff hiring and training practices, reduce environmental triggers for aggression, and develop policies to reduce motivation for aggression. PMID:21896078

  7. Maternal rank influences the outcome of aggressive interactions between immature chimpanzees

    PubMed Central

    Markham, A. Catherine; Lonsdorf, Elizabeth V.; Pusey, Anne E.; Murray, Carson M.

    2015-01-01

    For many long-lived mammalian species, extended maternal investment has a profound effect on offspring integration in complex social environments. One component of this investment may be aiding young in aggressive interactions, which can set the stage for offspring social position later in life. Here we examined maternal effects on dyadic aggressive interactions between immature (<12 years) chimpanzees. Specifically, we tested whether relative maternal rank predicted the probability of winning an aggressive interaction. We also examined maternal responses to aggressive interactions to determine whether maternal interventions explain interaction outcomes. Using a 12-year behavioural data set (2000–2011) from Gombe National Park, Tanzania, we found that relative maternal rank predicted the probability of winning aggressive interactions in male–male and male–female aggressive interactions: offspring were more likely to win if their mother outranked their opponent’s mother. Female–female aggressive interactions occurred infrequently (two interactions), so could not be analysed. The probability of winning was also higher for relatively older individuals in male–male interactions, and for males in male–female interactions. Maternal interventions were rare (7.3% of 137 interactions), suggesting that direct involvement does not explain the outcome for the vast majority of aggressive interactions. These findings provide important insight into the ontogeny of aggressive behaviour and early dominance relationships in wild apes and highlight a potential social advantage for offspring of higher-ranking mothers. This advantage may be particularly pronounced for sons, given male philopatry in chimpanzees and the potential for social status early in life to translate more directly to adult rank. PMID:25624528

  8. Classroom Environment Influences on Aggression, Peer Relations, and Academic Focus

    ERIC Educational Resources Information Center

    Barth, Joan M.; Dunlap, Sarah T.; Dane, Heather; Lochman, John E.; Wells, Karen C.

    2004-01-01

    Peers serve as reinforcers and models of behavior, and consequently classrooms containing high numbers of students with poor academic skills or behavior problems are likely to promote these behaviors in individual students. This study examined how variations in social and academic classroom composition as well as the larger school context affected…

  9. Effect of SO2 on oxidation of metallic materials in CO2/H2O-rich gases relevant to oxyfuel environments

    SciTech Connect

    Huczkowski, P.; Olszewski, T.; Schiek, M.; Lutz, B.; Holcomb, G.; Shemet, V.; Meier, G. H.; Singheiser, L.; Quadakkers, W. J.

    2012-09-19

    This report is a description of research performed by the Jülich Research Centre. Their conclusions outline the effects of SO2 additions on oxide formations and the interaction of other gases in oxvyfuel environments.

  10. Predicting aggression in children with ADHD

    PubMed Central

    2014-01-01

    Objective The present study uses structural equation modeling of latent traits to examine the extent to which family factors, cognitive factors and perceptions of rejection in mother-child relations differentially correlate with aggression at home and at school. Methods Data were collected from 476 school-age (7–15 years old) children with a diagnosis of ADHD who had previously shown different types of aggressive behavior, as well as from their parents and teachers. Structural equation modeling was used to examine the differential relationships between maternal rejection, family, cognitive factors and aggression in home and school settings. Results Family factors influenced aggression reported at home (.68) and at school (.44); maternal rejection seems to be related to aggression at home (.21). Cognitive factors influenced aggression reported at school (.-05) and at home (-.12). Conclusions Both genetic and environmental factors contribute to the development of aggressive behavior in ADHD. Identifying key risk factors will advance the development of appropriate clinical interventions and prevention strategies and will provide information to guide the targeting of resources to those children at highest risk. PMID:24860616

  11. Affective Dependence and Aggression: An Exploratory Study

    PubMed Central

    Petruccelli, Filippo; Diotaiuti, Pierluigi; Verrastro, Valeria; Petruccelli, Irene; Federico, Roberta; Martinotti, Giovanni; Fossati, Andrea; Di Giannantonio, Massimo; Janiri, Luigi

    2014-01-01

    Introduction. Emotionally dependent subjects may engage in controlling, restrictive, and aggressive behaviours, which limit their partner's autonomy. The underlying causes of such behaviours are not solely based on levels of aggression, but act as a mean of maintaining the subject's own sense of self-worth, identity, and general functioning. Objective. The aim of the paper is to explore the correlation between affective dependency and reactive/proactive aggression and to evaluate individual differences as predisposing factors for aggressive behaviour and emotional dependency. Methods. The Spouse-Specific Dependency Scale (SSDS) and the Reactive Proactive Questionnaire (RPQ) were administered to a sample of 3375 subjects. Results. In the whole sample, a positive correlation between emotional dependency and proactive aggression was identified. Differences with regard to sex, age group, and geographical distribution were evidenced for the scores of the different scales. Conclusion. A fundamental distinction between reactive and proactive aggression was observed, anchoring proactive aggression more strictly to emotional dependency. Sociocultural and demographical variables, together with the previous structuring of attachment styles, help to determine the scope, frequency, and intensity of the demands made to the partner, as well as to feed the fears of loss, abandonment, or betrayal. PMID:25054147

  12. Assessment of aggression in inpatient settings.

    PubMed

    McDermott, Barbara E; Holoyda, Brian J

    2014-10-01

    The threat of violence is a major concern for all individuals working or receiving treatment in an inpatient psychiatric setting. One major focus in forensic psychology and psychiatry over the past several decades has been the development of risk assessments to aid in the identification of those individuals most at risk of exhibiting violent behavior. So-called second- and third-generation risk assessments were developed to improve the accuracy of decision making. While these instruments were developed for use in the community, many have proven to be effective in identifying patients more likely to exhibit institutional aggression. Because the purpose of risk assessment is the reduction of violence, dynamic factors were included in third-generation risk instruments to provide opportunities for intervention and methods for measuring change. Research with these instruments indicates that both static factors (second-generation) and dynamic factors (third-generation) are important in identifying those patients most likely to engage in institutional aggression, especially when the aggression is categorized by type (impulsive/reactive, organized/predatory/instrumental, psychotic). Recent research has indicated that developing a typology of aggressive incidents may provide insight both into precipitants to assaults as well as appropriate interventions to reduce such aggression. The extant literature suggests that both static and dynamic risk factors are important, but may be differentially related to the type of aggression exhibited and the characteristics of the individuals exhibiting the aggression. PMID:25296966

  13. [Recognizing and assessing aggressive behaviour in dogs].

    PubMed

    Schalke, E; Hackbarth, H

    2006-03-01

    Within the population the sensitivity to aggressive behaviour in dogs has increased. The authorities are confronted with a problem: if any incident occurs it is their task to decide whether the dogs involved constitute a threat to other people or whether the charge is only the result of a quarrel between neighbours. For this reason, an examination of the dogs with regard to their aggressive behaviour is necessary. Seen from the biological point of view, aggressive behaviour is one of four possibilities a dog can chose from to solve a conflict. The dog's intention in showing aggressive behaviour is to eliminate disturbances and to maintain a distance in space and time. Aggressive behaviour might also be necessary to acquire or defend resources essential to the dog's life. This is to secure its survival and its success in reproduction. One can see from this that aggressive behaviour is a very important and biologically necessary adjustment factor. However, when living together with man aggressive behaviour might become a problem. For the assessment and the therapy of the problem it is necessary to exa-mine the behaviour shown by the dog with regard to its cause. To be able to do this an exact anamnesis, a medical check, and an examination of the dog on the basis of its display in special situations are necessary. For this reason, exclusively veterinarians with a special further education in the field of behaviour should carry out the examination of dogs. PMID:16669189

  14. Aggression inoculates against PTSD symptom severity—insights from armed groups in the eastern DR Congo

    PubMed Central

    Hecker, Tobias; Hermenau, Katharin; Maedl, Anna; Schauer, Maggie; Elbert, Thomas

    2013-01-01

    Background In the ongoing conflict in the Democratic Republic of the Congo (DRC), combatants are exposed to massive forms of violence and other traumatic stressors. Nevertheless, many combatants do not suffer from trauma-related disorders, although they have experienced numerous traumatizing events. Perceiving aggressive behavior as fascinating and arousing might be a defense against trauma-related disorders in the violent environment of war and conflict. Objective Thus, in this study we investigated the relationship between the exposure to traumatic stressors, appetitive aggression, and posttraumatic stress disorder (PTSD) symptom severity. We hypothesized that cumulative traumatic experiences correlated positively and appetitive aggression negatively with PTSD symptom severity. Method In total, 105 voluntary male combatants from different armed groups in the eastern DRC took part in this study. In a semistructured interview, respondents were questioned about their exposure to traumatic stressors, the extent of appetitive aggression (Appetitive Aggression Scale) and their PTSD symptom severity (PTSD Symptom Scale - Interview). Results A multiple sequential regression analysis showed that traumatic events were positively related to PTSD symptom severity. For participants with low to medium PTSD symptom severity, appetitive aggression correlated negatively with PTSD symptom severity. Conclusions The results of this study provide further support for earlier findings that repeated exposure to traumatic stressors cumulatively heightens the risk of PTSD and revealed that appetitive aggression buffers the risk of developing PTSD symptoms under certain circumstances. Thus, the perception of aggressive behavior as fascinating and arousing seem to help combatants to adapt to violent environments but may also be one reason for recurrent failure of reintegration programs for excombatants. PMID:23671766

  15. An examination of social cognitive theory with differences among sexually aggressive, physically aggressive and nonaggressive children in state care.

    PubMed

    Burton, D L

    1999-01-01

    Three groups of boys in Washington State care (37 sexually aggressive, 17 physically aggressive, and 15 nonaggressive) are compared on measures of behavior and cognition. Bandura's Social Cognition theory is offered as a possible explanation for sexual aggression by children. Two theory-based hypothesis are tested. First, are sexually aggressive children cognitively deficient when compared to the other groups? Second, do the sexually aggressive children have cognitive distortions about their behavior and about sex? Similarities were found in the aggressive and sexually aggressive groups on several measures. Physically aggressive boys were found to have some sexual behavior problems. Sexually aggressive boys were also found to be physically aggressive. Physically aggressive boys were found to have the least severe and least frequent victimization history. No support was found for the first hypothesis, while some evidence of cognitive distortions regarding both social behavior and sex was found in the sexually aggressive children. Discussion and some implications for research and practice are offered. PMID:10418769

  16. Aggressive behaviors in the psychiatric emergency service

    PubMed Central

    Chaput, Yves; Beaulieu, Lucie; Paradis, Michel; Labonté, Edith

    2011-01-01

    Introduction: Studies of aggressive behaviors in a nonforensic mental health setting have focused primarily on the inpatient ward and, on event prediction, using behavior-based clinical rating scales. Few studies have specifically targeted aggressive behaviors in the psychiatric emergency service or determined whether assessing the demographic and clinical characteristics of such patients might prove useful for their more rapid identification. Methods: We used a prospectively acquired database of over 20,900 visits to four services in the province of Quebec, Canada, over a two-year period from September 2002 onwards. A maximum of 72 variables could be acquired per visit. Visits with aggression (any verbally or physically intimidating behavior), both present and past, were tagged. Binary logistic regressions and cross-tabulations were used to determine whether the profile of a variable differed in visits with aggression from those without aggression. Results: About 7% of visits were marked by current aggression (verbal 49%, physical 12%, verbal and physical 39%). Including visits with a “past only” history of aggression increased this number to 20%. Variables associated with aggression were gender (male), marital status (single/separated), education (high school or less), employment (none), judicial history (any type), substance abuse (prior or active), medication compliance (poor), type of arrival to psychiatric emergency services (involuntary, police, judiciary, landlord), reason for referral (behavioral dyscontrol), diagnosis (less frequent in anxiety disorders), and outcome (more frequently placed under observation or admitted). Conclusion: Our results suggest that many state-independent variables are associated with aggressive behaviors in the psychiatric emergency service. Although their sum may not add up to a specific patient profile, they can nevertheless be useful in service planning, being easily integrated alongside state-dependent rating scales in a

  17. Testosterone and aggressive behavior in man.

    PubMed

    Batrinos, Menelaos L

    2012-01-01

    Atavistic residues of aggressive behavior prevailing in animal life, determined by testosterone, remain attenuated in man and suppressed through familial and social inhibitions. However, it still manifests itself in various intensities and forms from; thoughts, anger, verbal aggressiveness, competition, dominance behavior, to physical violence. Testosterone plays a significant role in the arousal of these behavioral manifestations in the brain centers involved in aggression and on the development of the muscular system that enables their realization. There is evidence that testosterone levels are higher in individuals with aggressive behavior, such as prisoners who have committed violent crimes. Several field studies have also shown that testosterone levels increase during the aggressive phases of sports games. In more sensitive laboratory paradigms, it has been observed that participant's testosterone rises in the winners of; competitions, dominance trials or in confrontations with factitious opponents. Aggressive behavior arises in the brain through interplay between subcortical structures in the amygdala and the hypothalamus in which emotions are born and the prefrontal cognitive centers where emotions are perceived and controlled. The action of testosterone on the brain begins in the embryonic stage. Earlier in development at the DNA level, the number of CAG repeats in the androgen receptor gene seems to play a role in the expression of aggressive behavior. Neuroimaging techniques in adult males have shown that testosterone activates the amygdala enhancing its emotional activity and its resistance to prefrontal restraining control. This effect is opposed by the action of cortisol which facilitates prefrontal area cognitive control on impulsive tendencies aroused in the subcortical structures. The degree of impulsivity is regulated by serotonin inhibiting receptors, and with the intervention of this neurotransmitter the major agents of the neuroendocrine

  18. Testosterone and Aggressive Behavior in Man

    PubMed Central

    Batrinos, Menelaos L.

    2012-01-01

    Atavistic residues of aggressive behavior prevailing in animal life, determined by testosterone, remain attenuated in man and suppressed through familial and social inhibitions. However, it still manifests itself in various intensities and forms from; thoughts, anger, verbal aggressiveness, competition, dominance behavior, to physical violence. Testosterone plays a significant role in the arousal of these behavioral manifestations in the brain centers involved in aggression and on the development of the muscular system that enables their realization. There is evidence that testosterone levels are higher in individuals with aggressive behavior, such as prisoners who have committed violent crimes. Several field studies have also shown that testosterone levels increase during the aggressive phases of sports games. In more sensitive laboratory paradigms, it has been observed that participant’s testosterone rises in the winners of; competitions, dominance trials or in confrontations with factitious opponents. Aggressive behavior arises in the brain through interplay between subcortical structures in the amygdala and the hypothalamus in which emotions are born and the prefrontal cognitive centers where emotions are perceived and controlled. The action of testosterone on the brain begins in the embryonic stage. Earlier in development at the DNA level, the number of CAG repeats in the androgen receptor gene seems to play a role in the expression of aggressive behavior. Neuroimaging techniques in adult males have shown that testosterone activates the amygdala enhancing its emotional activity and its resistance to prefrontal restraining control. This effect is opposed by the action of cortisol which facilitates prefrontal area cognitive control on impulsive tendencies aroused in the subcortical structures. The degree of impulsivity is regulated by serotonin inhibiting receptors, and with the intervention of this neurotransmitter the major agents of the neuroendocrine

  19. A COGNITIVE PERSPECTIVE ON AGGRESSIVE MIMICRY

    PubMed Central

    JACKSON, ROBERT R.; CROSS, FIONA R.

    2013-01-01

    We use the term ‘aggressive mimic’ for predators that communicate with their prey by making signals to indirectly manipulate prey behaviour. For understanding why the aggressive mimic’s signals work, it is important to appreciate that these signals interface with the prey’s perceptual system, and that the aggressive mimic can be envisaged as playing mind games with its prey. Examples of aggressive mimicry vary from instances in which specifying a model is straight forward to instances where a concise characterisation of the model is difficult. However, the less straightforward examples of aggressive mimicry may be the more interesting examples in the context of animal cognition. In particular, there are spiders that prey on other spiders by entering their prey’s web and making signals. Web invasion brings about especially intimate contact with their prey’s perceptual system because the prey spider’s web is an important component of the prey spider’s sensory apparatus. For the web-invading spider, often there is also a large element of risk when practising aggressive mimicry because the intended prey is also a potential predator. This element of risk, combined with exceptionally intimate interfacing with prey perceptual systems, may have favoured the web-invading aggressive mimic’s strategy becoming strikingly cognitive in character. Yet a high level of flexibility may be widespread among aggressive mimics in general and, on the whole, we propose that research on aggressive mimicry holds exceptional potential for advancing our understanding of animal cognition. PMID:23976823

  20. Chemical Characterisation of the Coarse and Fine Particulate Matter in the Environment of an Underground Railway System: Cytotoxic Effects and Oxidative Stress—A Preliminary Study

    PubMed Central

    Spagnolo, Anna Maria; Ottria, Gianluca; Perdelli, Fernanda; Cristina, Maria Luisa

    2015-01-01

    Background: Exposure to the particulate matter produced in underground railway systems is arousing increasing scientific interest because of its health effects. The aim of our study was to evaluate the airborne concentrations of PM10 and three sub-fractions of PM2.5 in an underground railway system environment in proximity to platforms and in underground commercial areas within the system, and to compare these with the outdoor airborne concentrations. We also evaluated the metal components, the cytotoxic properties of the various fractions of particulate matter (PM) and their capacity to induce oxidative stress. Method: We collected the coarse fraction (5–10 µm) and the fine fractions (1–2.5 µm; 0.5–1 µm; 0.25–0.5 µm). Chemical characterisation was determined by means of spectrometry. Cytotoxicity and oxidative stress were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Reactive Oxygen Species (ROS) assessment. Results: The concentrations of both PM10 and PM2.5 proved to be similar at the three sampling sites. Iron and other transition metals displayed a greater concentration at the subway platform than at the other two sites. The 2.5–10 µm and 1–2.5 µm fractions of PM from all three sampling sites determined a greater increase in ROS; the intensity of oxidative stress progressively declined as particle diameter diminished. Moreover, ROS concentrations were correlated with the concentrations of some transition metals, namely Mn, Cr, Ti, Fe, Cu, Zn, Ni and Mo. All particulate matter fractions displayed lower or similar ROS values between platform level and the outdoor air. Conclusions: The present study revealed that the underground railway environment at platform level, although containing higher concentrations of some particularly reactive metallic species, did not display higher cytotoxicity and oxidative stress levels than the outdoor air. PMID:25872016

  1. Verbal versus Physical Aggression in Intermittent Explosive Disorder

    PubMed Central

    Look, Amy E.; McCloskey, Michael S.; Coccaro, Emil F.

    2015-01-01

    Intermittent Explosive Disorder (IED) is the only adult psychiatric diagnosis for which pathological aggression is primary. DSM-IV criteria focused on physical aggression, but DSM-5 allows for an IED diagnosis in the presence of frequent verbal aggression with or without concurrent physical aggression. It remains unclear how individuals with verbal aggression differ from those with physical aggression with respect to cognitive-affective deficits and psychosocial functioning. The current study compared individuals who met IED criteria with either frequent verbal aggression without physical aggression (IED-V), physical aggression without frequent verbal aggression (IED-P), or both frequent verbal aggression and physical aggression (IED-B) as well as a non-aggressive personality-disordered (PD) comparison group using behavioral and self-report measures of aggression, anger, impulsivity, and affective lability, and psychosocial impairment. Results indicate all IED groups showed increased anger/aggression, psychosocial impairment, and affective lability relative to the PD group. The IED-B group showed greater trait anger, anger dyscontrol, and aggression compared to the IED-V and IED-P groups. Overall, the IED-V and IED-P groups reported comparable deficits and impairment. These results support the inclusion of verbal aggression within the IED criteria and suggest a more severe profile for individuals who engage in both frequent verbal arguments and repeated physical aggression. PMID:25534757

  2. Source Tracking of Nitrous Oxide using A Quantum Cascade Laser System in the Field and Laboratory Environments

    EPA Science Inventory

    Nitrous oxide is an important greenhouse gas and ozone depleting substance. Nitrification and denitrification are two major biological pathways that are responsible for soil emissions of N2O. However, source tracking of in-situ or laboratory N2O production is still challenging to...

  3. Understanding the corrosion behavior of chromia-forming 316L stainless steel in dual oxidizing-reducing environment representative of SOFC interconnect

    SciTech Connect

    Ziomek-Moroz, Margaret; Cramer, Stephen D.; Holcomb, Gordon R.; Covino, Bernard S., Jr.; Matthes, Steven A.; Bullard, Sophie J.; Dunning, John S.; Alman, David E.; Singh, P.

    2003-11-01

    A and B site doped LaCrO3-based electronically conducting Perovskite ceramic materials have been extensively used as interconnects in solid oxide fule cells (SOFC) operating at 800° to 1000°C as the Perovskites offer good electrical conductivity, chemical compatibility with the adjacent components of the fuel cell, chemical stability in reducing and oxidizing atmospheres, and thermal expansion coefficients that match other cell components. However, requirements for good mechanical properties, electrical and thermal conductivities, and low cost make metallic interconnects more promising. Significant progress in reducing the operating temperature of SOFC from ~1000°C to ~750°C is expected to permit the use of metallic materials with substantial cost reduction. Among the commercially available metallic materials, Cr2O3 (chromia) scale-forming iron base alloys appear to be the most promising candidates since they can fulfill the technical and economical requirements. These alloys, however, remain prone to reactions with oxygen and water vapor at fuel cell operating conditions and formation of gaseous chromium oxides and oxyhydroxides. To study the degradation processes and corrosion mechanisms of commercial chromia scale-forming alloys under SOFC interconnect exposure conditions, 316L was selected for this research because of the availability of the materials. The dual environment to which the interconnect material was exposed consisted of dry air (simulates the cathode side environment) and a mixture of H2 and 3% H2O (simulates the anode side environment). Post-corrosion surface evaluation involved the use of optical and scanning electron microscopy, as well as energy dispersive X-ray analyses.

  4. Adolescent Aggression: The Role of Peer Group Status Motives, Peer Aggression, and Group Characteristics.

    PubMed

    Faris, Robert; Ennett, Susan

    2012-10-01

    Recent studies of youth aggression have emphasized the role of network-based peer influence processes. Other scholars have suggested that aggression is often motivated by status concerns. We integrate these two veins of research by considering the effects of peer status motivations on subsequent adolescent aggression, net of their own status motivations, prior aggression, and peer behavior. We also explore different levels at which peer effects may occur, considering the effects of reciprocated and unreciprocated friendships as well as larger, meso-level peer groups. We anticipate that peer group effects are magnified by both size and boundedness as measured by Freeman's (1972) Segregation Index. We find that, net of the adolescent's aggression at time 1, both the aggressive behaviors and the status valuations of friends independently increase the likelihood of aggression at time 2, six months later. The aggressive behavior of friends who do not reciprocate the adolescent's friendship nomination has particular impact. The average status valuation of peer groups increases their members' likelihood of aggression, even after controlling for their own attitudes about status, their friends' attitudes, and their friends' aggressive behavior. This effect is magnified in large groups and groups with high Freeman segregation scores. PMID:25152562

  5. Understanding the personality disorder and aggression relationship: an investigation using contemporary aggression theory.

    PubMed

    Gilbert, Flora; Daffern, Michael; Talevski, Diana; Ogloff, James R P

    2015-02-01

    Research has consistently demonstrated a link between certain personality disorders (PDs) and increased rates of aggression and violence. At present, understanding of the mechanisms that underlie this relationship is limited. This study was designed to examine the contention (Gilbert & Daffern, 2011) that the application of a contemporary psychological aggression theory, the General Aggression Model (GAM; Anderson & Bushman, 2002), may assist in elucidating the PD-aggression relationship. Eighty-seven offenders undergoing presentence evaluation were assessed for Axis II PDs and psychopathy, aggression, and three constructs delineated by the GAM: scripts, normative beliefs, and anger. Regression analyses were undertaken to examine the relative contributions of these variables to aggression. The results upheld a relationship between several PDs and aggression, and suggested that for these PDs, the consideration of scripts, beliefs supportive of aggression, and anger facilitated an improved understanding of aggressiveness. Overall, the findings indicate that the GAM offers valuable insight into the psychological features that characterize individuals with PD who are prone to aggression. PMID:23398093

  6. Mild hypoglycaemia and questionnaire measures of aggression.

    PubMed

    Benton, D; Kumari, N; Brain, P F

    1982-01-01

    A glucose-tolerance test was given to a group of males who did not have a history involving aggressive behaviour or abnormal glucose metabolism. In these subjects a significant correlation was found between the tendency to become mildly hypoglycaemic and scores on the Buss-Durkee Hostility Inventory and the Rosenzweig Picture Frustration Study. A factor analysis of the data found that both scores on the aggression questionnaires and the measure of hypoglycaemia were similarly weighted. These results extent to normal subjects the finding that there is a relationship between hypoglycaemia and aggressiveness, a result previously found in psychiatric patients. PMID:7104424

  7. [Aggressive behavior: theoretical and biological aspects].

    PubMed

    Giotakos, O

    2013-01-01

    The susceptibility to aggression may manifest differently depending on the psychological context in which it occurs. In the context of psychopathy, characterized by a lack of empathy, this may manifest in aggression with criminal acts, which is characteristic of antisocial personality disorder. When the susceptibility is associated with psychotic impairment, aggression may be manifested in highly deviant behavior, like murder or serial killing. While the great majority of persons with schizophrenia do not commit violent acts, clinicians suggest that some schizophrenics may pose a risk in the community, particularly those patients with co-occurring substance abuse diagnoses, those who are noncompliant with prescribed psychiatric treatment, and those with a history of frequent relapses resulting in hospitalization or arrest. Episodic violence and aggression often accompany dementia. When coupled with emotional dysregulation, impulsive aggression often occurs in an interpersonal context, as in borderline personality disorder. However, the most common comorbidity is the substance abuse disorder, which contributes to both the cognitive distortions and disinhibition associated with the substance use. According to the biological data, aggression seems to emerge when the drive of limbic-mediated affective prefrontal response to provocative producing stimuli is insufficiently constrained by inhibition. Thus, excessive reactivity in the amygdale, coupled with inadequate prefrontal regulation, increase the possibility of aggressive behavior. The PET/SPECT studies focusing on schizophrenia have shown reduced activity in fronto-temoral circuitry. The fMRI studies concord with the hypothesis that among violent persons with schizophrenia, those with sociopathetic features and/or substance abuse constitute a highly different subgroup, in which cognitive, neurological and behavioral patterns are more closely associated with the personality traits than schizophrenia. It is known

  8. The response to oxidative stress and metallomics analysis in a twin study: The role of the environment.

    PubMed

    Medda, Emanuela; Minoprio, Anna; Nisticò, Lorenza; Bocca, Beatrice; Simonelli, Valeria; D'Errico, Mariarosaria; Calcagnile, Angelo; Giuliani, Alessandro; Toccaceli, Virgilia; Minghetti, Luisa; Alimonti, Alessandro; Stazi, Maria Antonietta; Mazzei, Filomena; Dogliotti, Eugenia

    2016-08-01

    Inefficient response to oxidative stress has been associated with ageing and health risk. Metals are known to inhibit DNA repair and may modify the antioxidant response. How genetic variability and lifestyle factors modulate the response to oxidative stress is poorly explored. Our study aims to disentangle the contribution of genetics and environmental exposures to oxidative stress response using data from twin pairs. The non-enzymatic antioxidant capacity (NEAC), the repair capacity of 8-oxo-7,8-dihydroguanine (OGG activity) and the levels of 12 metals were measured in blood of 64 monozygotic and 31 dizygotic twin pairs. The contributions of genetic and environmental effects were assessed using standard univariate twin modelling. NEAC and OGG activity significantly decreased with age. Gender-, age- and body mass index-associated differences were identified for some metals. Principal Component Analysis identified two groups of metals whose levels in blood were highly correlated: As, Hg, Pb, Se, Zn and Al, Co, Cr, Mn, Ni. The environmental influence was predominant on OGG activity and NEAC variance whereas for most metals the best-fitting model incorporated additive genetic and unique environmental sources of variance. NEAC and OGG activity were both inversely correlated with blood levels of various metals. The inhibition of OGG activity by Cd was largely explained by smoking. Our data show a substantial role of environmental factors in NEAC and OGG activity variance that is not explained by twins' age. Exogenous environmental factors such as metals contribute to oxidative stress by decreasing NEAC and inhibiting repair of oxidatively-induced DNA damage. PMID:27264237

  9. Effects of aggressive remediation on soil properties and function

    NASA Astrophysics Data System (ADS)

    Switzer, Christine; Zihms, Stephanie; Pape, Andrew; Robson, Andrew; Knapp, Charles

    2013-04-01

    Aggressive remediation processes such as thermal desorption, smouldering, and chemical oxidiation remediation processes have significant promise to deliver substantial contaminant reduction in short periods of time, effecting as much as 95-99+% mass removal from non-aqueous phase liquid (NAPL) source zones. In situ thermal remediation exposes soils to temperatures of 100+°C for periods of weeks or months. In situ smouldering exposes soils to 600-1000+°C for hours to days. Chemical oxidation exposes soils to harsh oxidizing chemicals for weeks or months effecting reactive degradation of chemical contaminants but also surrounding soils. These processes have the potential to result in significant changes to the soil properties, particularly at the particle surface and grain interfaces. The dynamic effects of these changes have important implications in soil management practice. The mobilisation of soil nutrients may challenge rehabilitation or biological "polishing" after aggressive remediation. Plant germination and growth are inhibited and water dynamics are affected as well. Although permeability remains unaffected, infiltration is more rapid and capillary rise is reduced after smouldering remediation. Mobilisation of fines does not explain the change in infiltration and capillary rise; these effects persist after removal of the smaller half of the particle size distribution. Some separation of the soil column is observed in water infiltration after both thermal and smouldering remediation, indicating that erosion and subsidence are potential problems. These effects may be manifestations of subcritical water repellency. Based on the retention of capillary rise and lack of effects on other soil properties, the soil should be amenable to improvement measures. This presentation will place the effects of aggressive remediation into context within real soils and model materials.

  10. Preparation of Crumpled Graphite Oxide from Recycled Graphite Using Plasma Electrolysis and Its Application for Adsorption of Cadmium in Aqueous Environment

    NASA Astrophysics Data System (ADS)

    Hong, Phan Ngoc; Tuoi, Tran Thi; Ngan, Nguyen Thi Kim; Trang, Bui Thi; Minh, Phan Ngoc; Lam, Tran Dai; Hanh, Nguyen Thi; Van Thanh, Dang

    2016-05-01

    Household battery waste is considered hazardous and needs to be collected, managed, and recycled appropriately. In this study, using a plasma electrolysis method, we recycled graphite electrodes of exhausted dry batteries to prepare crumpled graphite oxide (CGO). Scanning electron microscopy revealed that the CGO possessed spherical morphology with average dimensions of 0.5 μm to 5 μm. The as-prepared CGO was then applied to absorb cadmium in aqueous environment. The results showed that CGO appears to be a promising adsorbent for removal of toxic waste from polluted water.

  11. Low cycle fatigue life of two nickel-base casting alloys in a hydrogen environment. [for high-pressure oxidizer turbopump turbine nozzles

    NASA Technical Reports Server (NTRS)

    Cooper, R. A.

    1976-01-01

    Samples of two nickel-base casting alloys, Mar-M-246 (a Martin Company alloy) and 713LC (a low-carbon modification of the alloy 713C developed by International Nickel Company) were tested as candidate materials for the high-pressure fuel and high-pressure oxidizer turbopump turbine nozzles. The samples were subjected to tensile tests and to low cycle fatigue tests in high-pressure hydrogen to study the influence of the hydrogen environment. The Mar-M-246 material was found to have a three times higher cyclic life in hydrogen than the 713LC alloy, and was selected as the nozzle material.

  12. Formation of metal oxides by cathodic arc deposition

    SciTech Connect

    Anders, S.; Anders, A.; Rubin, M.; Wang, Z.; Raoux, S.; Kong, F.; Brown, I.G.

    1995-03-01

    Metal oxide thin films are of interest for a number of applications. Cathodic arc deposition, an established, industrially applied technique for formation of nitrides (e.g. TiN), can also be used for metal oxide thin film formation. A cathodic arc plasma source with desired cathode material is operated in an oxygen atmosphere, and metal oxides of various stoichiometric composition can be formed on different substrates. We report here on a series of experiments on metal oxide formation by cathodic arc deposition for different applications. Black copper oxide has been deposited on ALS components to increase the radiative heat transfer between the parts. Various metal oxides such as tungsten oxide, niobium oxide, nickel oxide and vanadium oxide have been deposited on ITO glass to form electrochromic films for window applications. Tantalum oxide films are of interest for replacing polymer electrolytes. Optical waveguide structures can be formed by refractive index variation using oxide multilayers. We have synthesized multilayers of Al{sub 2}O{sub 3}/Y{sub 2}O{sub 3}/AI{sub 2}O{sub 3}/Si as possible basic structures for passive optoelectronic integrated circuits, and Al{sub 2-x}Er{sub x}O{sub 3} thin films with a variable Er concentration which is a potential component layer for the production of active optoelectronic integrated devices such as amplifiers or lasers at a wavelength of 1.53 {mu}m. Aluminum and chromium oxide films have been deposited on a number of substrates to impart improved corrosion resistance at high temperature. Titanium sub-oxides which are electrically conductive and corrosion resistant and stable in a number of aggressive environments have been deposited on various substrates. These sub-oxides are of great interest for use in electrochemical cells.

  13. Alcohol Expectancies and Evaluations of Aggression in Alcohol-Related Intimate-Partner Verbal and Physical Aggression

    PubMed Central

    Kachadourian, Lorig K; Quigley, Brian M; Leonard, Kenneth E

    2014-01-01

    Objective: Alcohol aggression expectancies have been found to be associated with increases in aggressive behavior. However, research has not consistently examined evaluations of such behavior. This is unfortunate as both expectancies and evaluations may play a role in whether such behavior will occur. Given this, the current study cross-sectionally examined the associations between alcohol aggression expectancies, evaluations of alcohol-related aggression, indicators of excessive drinking, and alcohol-related verbal and physical aggression. Method: The sample consisted of 280 married and cohabiting couples. These couples reported on excessive drinking indicators, alcohol expectancies and evaluations, and alcohol-related verbal and physical aggression during the past year. Results: Findings showed that verbal aggression was positively associated with indicators of excessive drinking among females and with alcohol aggression expectancies for females who evaluated such aggression positively. For males, aggression expectancies and indicators of excessive drinking were positively associated with verbal aggression. For physical aggression, results showed that indicators of excessive drinking and aggression expectancies were associated with physical aggression for females. For males, aggression expectancies were positively associated and evaluations were negatively associated with physical aggression. Conclusions: These findings add to previous research on alcohol aggression expectancies in close relationships and emphasize the importance of considering evaluations of alcohol-related behavior and how they may play a role in intimate-partner violence and aggression. PMID:25208191

  14. Effects of deindividuating situational cues and aggressive models on subjective deindividuation and aggression.

    PubMed

    Prentice-Dunn, S; Rogers, R W

    1980-07-01

    This experiment demonstrated that a subjective state of deindividuation mediates the effect of deindividuating situational cues on aggression displayed by small groups (n = 4) of coacting aggressors. The deindividuated state was composed of two factors, Self-Awareness and Altered Experiencing, both of which had a causal influence on aggressive behavior. These data are interpreted in terms of deindividuation theories which assume that certain input variables reduce self-awareness and concern about social evaluation and thereby weaken the restraints against expressing antisocial behavior. Also as predicted, compared with a no-model control condition, a high-aggressive model disinhibited overt displays of aggression, whereas a low-aggressive model inhibited aggression among both individuated and deindividuated group members. PMID:7411390

  15. Breast Cancers Between Mammograms Have Aggressive Features

    Cancer.gov

    Breast cancers that are discovered in the period between regular screening mammograms—known as interval cancers—are more likely to have features associated with aggressive behavior and a poor prognosis than cancers found via screening mammograms.

  16. Research: Television Violence and Aggressive Behavior.

    ERIC Educational Resources Information Center

    Wurtzel, Alan

    1977-01-01

    Summarizes the major research findings on the relationship between television violence and aggressive behavior; concludes that, while there is no definitive proof that such a relationship exists, the evidence points strongly in that direction. (GT)

  17. Human Aggression Linked to Chemical Balance

    ERIC Educational Resources Information Center

    Science News, 1978

    1978-01-01

    Recent studies done by federal researchers indicate that human aggression may be affected by a critical balance of two or three key brain chemical neurotransmitters. Results of this study with human beings are included in this article. (MA)

  18. REPEATED REDUCTIVE AND OXIDATIVE TREATMENTS ON GRANULAR ACTIVATED CARBON

    EPA Science Inventory

    Fenton oxidation and Fenton oxidation preceded by reduction solutions were applied to granular activated carbon (GAC) to chemically regenerate the adsorbent. No adsorbate was present on the GAC so physicochemical effects from chemically aggressive regeneration of the carbon coul...

  19. The oxidation of Cr(III) to Cr(VI) in the environment by atmospheric oxygen during the bush fires.

    PubMed

    Panichev, N; Mabasa, W; Ngobeni, P; Mandiwana, K; Panicheva, S

    2008-05-30

    The presence of Cr(VI) in soils and plants of remote unpolluted areas can be explained by partial oxidation of Cr(III) with atmospheric oxygen during seasonable bush fires, which are rather frequent event in South Africa. Experiments with thermal treatment of a veld grass, Hyperthelia dissoluta, in muffle furnace at high temperature, followed by electrothermal atomic absorption spectrometry (ETAAS) determination of chromium, show a remarkable increase in Cr(VI) concentration from initial 2.5 to 23.2% after the treatment of grass ash at 500 degrees C and to 58.1% at 900 degrees C. Before ETAAS determination, the two chromium species of interest were separated by the treatment of samples with 0.1M Na2CO3. Thermodynamic calculations confirm the possibility of Cr(III) to Cr(VI) oxidation with atmospheric oxygen at high temperature in alkaline media, which is typical for vegetation ash. Analysis of field samples show that percent of Cr(VI), in respect to the total amount of chromium increased from initial 2.5% in grass to 9.3% in ash of grass. Without oxidation the percent of Cr(VI) in grass and ash of grass should be a constant value. After the fire Cr(VI) concentration in top soil (0-3 cm) increased from 0.3+/-0.05 to 1.8+/-0.5 microg g(-1) and the total Cr from 26+/-9 to 69+/-14 microg g(-1). The reason for the appearance of additional amount of Cr on top soil can be explained by condensation of chromium species from flame and shouldering ash on a soil surface. The results of studies demonstrate that Cr(VI) is formed by Cr(III) oxidation with atmospheric oxygen at high temperature during bush fires. PMID:17980482

  20. Plant Survival in a Changing Environment: The Role of Nitric Oxide in Plant Responses to Abiotic Stress

    PubMed Central

    Simontacchi, Marcela; Galatro, Andrea; Ramos-Artuso, Facundo; Santa-María, Guillermo E.

    2015-01-01

    Nitric oxide in plants may originate endogenously or come from surrounding atmosphere and soil. Interestingly, this gaseous free radical is far from having a constant level and varies greatly among tissues depending on a given plant’s ontogeny and environmental fluctuations. Proper plant growth, vegetative development, and reproduction require the integration of plant hormonal activity with the antioxidant network, as well as the maintenance of concentration of reactive oxygen and nitrogen species within a narrow range. Plants are frequently faced with abiotic stress conditions such as low nutrient availability, salinity, drought, high ultraviolet (UV) radiation and extreme temperatures, which can influence developmental processes and lead to growth restriction making adaptive responses the plant’s priority. The ability of plants to respond and survive under environmental-stress conditions involves sensing and signaling events where nitric oxide becomes a critical component mediating hormonal actions, interacting with reactive oxygen species, and modulating gene expression and protein activity. This review focuses on the current knowledge of the role of nitric oxide in adaptive plant responses to some specific abiotic stress conditions, particularly low mineral nutrient supply, drought, salinity and high UV-B radiation. PMID:26617619

  1. Production of nitrogen oxides by lightning and coronae discharges in simulated early Earth, Venus and Mars environments

    NASA Astrophysics Data System (ADS)

    Nna Mvondo, D.; Navarro-González, R.; McKay, C. P.; Coll, P.; Raulin, F.

    We present measurements for the production of nitrogen oxides (NO and N 2O) in CO 2-N 2 mixtures that simulate different stages of the evolution of the atmospheres of the Earth, Venus and Mars. The nitrogen fixation rates by two different types of electrical discharges, namely lightning and coronae, were studied over a wide range in CO 2 and N 2 mixing ratios. Nitric oxide (NO) is formed with a maximum energy yield estimated to be ˜1.3×10 16 molecule J -1 at 80% CO 2 and ˜1.3×10 14 molecule J -1 at 50% CO 2 for lightning and coronae discharges, respectively. Nitrous oxide (N 2O) is only formed by coronae discharge with a maximum energy yield estimated to be ˜1.2×10 13 molecule J -1 at 50% CO 2. The pronounced difference in NO production in lightning and coronae discharges and the lack of formation of N 2O in lightning indicate that the physics and chemistry involved in nitrogen fixation differs substantially in these two forms of electric energy.

  2. Plant Survival in a Changing Environment: The Role of Nitric Oxide in Plant Responses to Abiotic Stress.

    PubMed

    Simontacchi, Marcela; Galatro, Andrea; Ramos-Artuso, Facundo; Santa-María, Guillermo E

    2015-01-01

    Nitric oxide in plants may originate endogenously or come from surrounding atmosphere and soil. Interestingly, this gaseous free radical is far from having a constant level and varies greatly among tissues depending on a given plant's ontogeny and environmental fluctuations. Proper plant growth, vegetative development, and reproduction require the integration of plant hormonal activity with the antioxidant network, as well as the maintenance of concentration of reactive oxygen and nitrogen species within a narrow range. Plants are frequently faced with abiotic stress conditions such as low nutrient availability, salinity, drought, high ultraviolet (UV) radiation and extreme temperatures, which can influence developmental processes and lead to growth restriction making adaptive responses the plant's priority. The ability of plants to respond and survive under environmental-stress conditions involves sensing and signaling events where nitric oxide becomes a critical component mediating hormonal actions, interacting with reactive oxygen species, and modulating gene expression and protein activity. This review focuses on the current knowledge of the role of nitric oxide in adaptive plant responses to some specific abiotic stress conditions, particularly low mineral nutrient supply, drought, salinity and high UV-B radiation. PMID:26617619

  3. Effects of 1000 C oxide surfaces on room temperature aqueous corrosion and environmental embrittlement of iron aluminides

    SciTech Connect

    Buchanan, R.A.; Perrin, R.L.

    1997-12-01

    Results of electrochemical aqueous-corrosion studies at room temperature indicate that retained in-service-type high-temperature surface oxides (1000 C in air for 24 hours) on FA-129, FAL and FAL-Mo iron aluminides cause major reductions in pitting corrosion resistance in a mild acid-chloride solution designed to simulate aggressive atmospheric corrosion. Removal of the oxides by mechanical grinding restores the corrosion resistance. In a more aggressive sodium tetrathionate solution, designed to simulate an aqueous environment contaminated by sulfur-bearing combustion products, only active corrosion occurs for both the 1000 C oxide and mechanically cleaned surfaces at FAL. Results of slow-strain-rate stress-corrosion-cracking tests on FA-129, FAL and FAL-Mo at free-corrosion and hydrogen-charging potentials in the mild acid chloride solution indicate somewhat higher ductilities (on the order of 50%) for the 1000 C oxides retard the penetration of hydrogen into the metal substrates and, consequently, are beneficial in terms of improving resistance to environmental embrittlement. In the aggressive sodium tetrathionate solution, no differences are observed in the ductilities produced by the 1000 C oxide and mechanically cleaned surfaces for FAL.

  4. Female competition and aggression: interdisciplinary perspectives

    PubMed Central

    Stockley, Paula; Campbell, Anne

    2013-01-01

    This paper introduces a Theme Issue combining interdisciplinary perspectives in the study of female competition and aggression. Despite a history of being largely overlooked, evidence is now accumulating for the widespread evolutionary significance of female competition. Here, we provide a synthesis of contributions to this Theme Issue on humans and other vertebrates, and highlight directions for future research. Females compete for resources needed to survive and reproduce, and for preferred mates. Although female aggression takes diverse forms, under most circumstances relatively low-risk competitive strategies are favoured, most probably due to constraints of offspring production and care. In social species, dominance relationships and threats of punishment can resolve social conflict without resort to direct aggression, and coalitions or alliances may reduce risk of retaliation. Consistent with these trends, indirect aggression is a low cost but effective form of competition among young women. Costs are also minimized by flexibility in expression of competitive traits, with aggressive behaviour and competitive signalling tailored to social and ecological conditions. Future research on female competition and the proximate mediators of female aggression will be greatly enhanced by opportunities for interdisciplinary exchange, as evidenced by contributions to this Theme Issue. PMID:24167303

  5. [Plasma amino acid concentrations in aggressive dogs].

    PubMed

    Juhr, Norbert-Christian; Brand, Ulrike; Riedel, Eberhard

    2005-01-01

    Following the hypothesis that metabolic screens may be useful tools in the diagnosis of canine aggression we have investigated the blood plasma amino acid levels of dogs which have been found aggressive (N = 10) against dogs or men in comparison to non-aggressive dogs (N = 10). In summary, the aggressive dogs showed elevated plasma concentrations of the neurophysiological active aromatic amino acids tryptophan (46/171 micromol/l, p < 0,001), tyrosine (38/67 micromol/l, p < 0.01) and histidine (74/91 micromol/l, p < 0.01) and lower lysine concentrations (175/151 micromol/l, p < 0.05), which seems to point to a stress situation of these dogs. The nitrogen metabolism is impaired in the urea-cycle in the conversion of ornithine (17/34 micromol/l, p < 0.01) to citrulline (64/47 micromol/l). Higher levels of branched chain amino acids, especially leucine (122/150 micromol/l, p < 0.01), mainly metabolized in muscles, and isoleucin (60/71 micromol/l, p < 0.05) show a high energy potential. The acidose-stimulator methionine (48/78 micromol/l, p < 0.01) proved elevated. The results show that the changed behavior in the aggressive dogs is also reflected in their free amino acid plasma concentrations, independent of the question whether these data are the cause or the result of the aggressivity. PMID:15803756

  6. Approach and avoidance towards aggressive stimuli and its relation to reactive and proactive aggression.

    PubMed

    Lobbestael, Jill; Cousijn, Janna; Brugman, Suzanne; Wiers, Reinout W

    2016-06-30

    This study assessed the association between indirectly measured behavioural approach- and avoidance-related tendencies on the one hand, and reactive versus proactive aggression on the other hand. Reactive aggression (i.e. the impulsive, anger-driven aggression expressed in response to threatening stimuli) was differentiated from proactive aggression (i.e. the more controlled aggression motivated towards obtaining specific goals). A mixed sample of 118 patients and healthy controls filled out a self-report measure to assess their degree of reactive and proactive aggression, and then performed an Approach Avoidance Task in which they were asked to pull or push a joystick in response to a format-feature of a series of pictures, irrespective of their contents. The pictorial stimuli used in this task included attack-related scenes and angry faces, along with neutral, positive and negative control stimuli. The results were controlled for the level of personality disorder pathology, gender, and age. The findings indicated that reactive but not proactive aggression was related to the relative behavioural tendency to approach attack-related scenes, along with positive stimuli. These findings reflect the hyper-reactivity of the approach-related reward system in reactive aggression, and further our knowledge into the distinct correlates and precursors of reactive and proactive aggression. PMID:27111213

  7. TolC is important for bacterial survival and oxidative stress response in Salmonella enterica serovar Choleraesuis in an acidic environment.

    PubMed

    Lee, Jen-Jie; Wu, Ying-Chen; Kuo, Chih-Jung; Hsuan, Shih-Ling; Chen, Ter-Hsin

    2016-09-25

    The outer membrane protein TolC, which is one of the key components of several multidrug efflux pumps, is thought to be involved in various independent systems in Enterobacteriaceae. Since the acidic environment of the stomach is an important protection barrier against foodborne pathogen infections in hosts, we evaluated whether TolC played a role in the acid tolerance of Salmonella enterica serovar Choleraesuis. Comparison of the acid tolerance of the tolC mutant and the parental wild-type strain showed that the absence of TolC limits the ability of Salmonella to sustain life under extreme acidic conditions. Additionally, the mutant exhibited morphological changes during growth in an acidic medium, leading to the conflicting results of cell viability measured by spectrophotometry and colony-forming unit counting. Reverse-transcriptional-PCR analysis indicated that acid-related molecules, apparatus, or enzymes and oxidation-induced factors were significantly affected by the acidic environment in the null-tolC mutant. The elongated cellular morphology was restored by adding antioxidants to the culture medium. Furthermore, we found that increased cellular antioxidative activity provides an overlapping protection against acid killing, demonstrating the complexity of the bacterial acid stress response. Our findings reinforce the multifunctional characteristics of TolC in acid tolerance or oxidative stress resistance and support the correlative protection mechanism between oxygen- and acid-mediated stress responses in Salmonella enterica serovar Choleraesuis. PMID:27599929

  8. Subsurface characterization of an oxidation-induced phase transformation and twinning in nickel-based superalloy exposed to oxy-combustion environments

    SciTech Connect

    Zhu, Jingxi; Holcomb, Gordon R.; Jablonski, Paul D.; Wise, Adam; Li, Jia; Laughlin, David E.; Sridhar, Seetharaman

    2012-07-30

    In the integration of oxy-fuel combustion to turbine power generation system, turbine alloys are exposed to high temperature and an atmosphere comprised of steam, CO{sub 2} and O{sub 2}. While surface and internal oxidation of the alloy takes place, the microstructure in the subsurface region also changes due to oxidation. In this study, bare metal coupons of Ni-base superalloys were exposed in oxy-fuel combustion environment for up to 1000 h and the oxidation-related microstructures were examined. Phase transformation occurred in the subsurface region in Ni-based superalloy and led to twinning. The transformation product phases were analyzed through thermodynamic equilibrium calculations and various electron microscopy techniques, including scanning electron microscopy (SEM), orientation imaging microscopy (OIM) and transmission electron microscopy (TEM). The mechanism by which the phase transformation and the formation of the microstructure occurred was also discussed. The possible effects of the product phases on the performance of the alloy in service were discussed.

  9. The challenging environment on board the International Space Station affects endothelial cell function by triggering oxidative stress through thioredoxin interacting protein overexpression: the ESA-SPHINX experiment.

    PubMed

    Versari, Silvia; Longinotti, Giulia; Barenghi, Livia; Maier, Jeanette Anne Marie; Bradamante, Silvia

    2013-11-01

    Exposure to microgravity generates alterations that are similar to those involved in age-related diseases, such as cardiovascular deconditioning, bone loss, muscle atrophy, and immune response impairment. Endothelial dysfunction is the common denominator. To shed light on the underlying mechanism, we participated in the Progress 40P mission with Spaceflight of Human Umbilical Vein Endothelial Cells (HUVECs): an Integrated Experiment (SPHINX), which consisted of 12 in-flight and 12 ground-based control modules and lasted 10 d. Postflight microarray analysis revealed 1023 significantly modulated genes, the majority of which are involved in cell adhesion, oxidative phosphorylation, stress responses, cell cycle, and apoptosis. Thioredoxin-interacting protein was the most up-regulated (33-fold), heat-shock proteins 70 and 90 the most down-regulated (5.6-fold). Ion channels (TPCN1, KCNG2, KCNJ14, KCNG1, KCNT1, TRPM1, CLCN4, CLCA2), mitochondrial oxidative phosphorylation, and focal adhesion were widely affected. Cytokine detection in the culture media indicated significant increased secretion of interleukin-1α and interleukin-1β. Nitric oxide was found not modulated. Our data suggest that in cultured HUVECs, microgravity affects the same molecular machinery responsible for sensing alterations of flow and generates a prooxidative environment that activates inflammatory responses, alters endothelial behavior, and promotes senescence. PMID:23913861

  10. Increased dietary iron and radiation in rats promote oxidative stress, induce localized and systemic immune system responses, and alter colon mucosal environment.

    PubMed

    Morgan, Jennifer L L; Ritchie, Lauren E; Crucian, Brian E; Theriot, Corey; Wu, Honglu; Sams, Clarence; Smith, Scott M; Turner, Nancy D; Zwart, Sara R

    2014-03-01

    Astronauts are exposed to increased body iron stores and radiation, both of which can cause oxidative damage leading to negative health effects. The purpose of this study was to investigate combined effects of high dietary iron (650 mg/kg diet) and radiation exposure (0.375 Gy cesium-137 every other day for 16 d) on markers of oxidative stress, immune system function, and colon mucosal environment in male Sprague-Dawley rats (n=8/group). Control rats consumed adequate iron (45 mg/kg diet) and were not irradiated. Combined treatments increased liver glutathione peroxidase, serum catalase, and colon myeloperoxidase while decreasing total fecal short-chain fatty acid concentrations. The high-iron diet alone increased leukocyte count. Radiation decreased the T-cell CD4:CD8 ratio. Plasma iron was negatively correlated with cytokine production in activated monocytes. Genes involved in colon microbial signaling, immune response, and injury repair were altered by radiation. Genes involved with injury repair and pathogen recognition changed with dietary iron. These data demonstrate that dietary iron and radiation, alone and combined, contribute to oxidative stress that is related to immune system alterations in circulation and the colon. The model presented may help us better understand the changes to these systems that have been identified among astronauts. PMID:24334706

  11. When David beats Goliath: the advantage of large size in interspecific aggressive contests declines over evolutionary time.

    PubMed

    Martin, Paul R; Ghalambor, Cameron K

    2014-01-01

    Body size has long been recognized to play a key role in shaping species interactions. For example, while small species thrive in a diversity of environments, they typically lose aggressive contests for resources with larger species. However, numerous examples exist of smaller species dominating larger species during aggressive interactions, suggesting that the evolution of traits can allow species to overcome the competitive disadvantage of small size. If these traits accumulate as lineages diverge, then the advantage of large size in interspecific aggressive interactions should decline with increased evolutionary distance. We tested this hypothesis using data on the outcomes of 23,362 aggressive interactions among 246 bird species pairs involving vultures at carcasses, hummingbirds at nectar sources, and antbirds and woodcreepers at army ant swarms. We found the advantage of large size declined as species became more evolutionarily divergent, and smaller species were more likely to dominate aggressive contests when interacting with more distantly-related species. These results appear to be caused by both the evolution of traits in smaller species that enhanced their abilities in aggressive contests, and the evolution of traits in larger species that were adaptive for other functions, but compromised their abilities to compete aggressively. Specific traits that may provide advantages to small species in aggressive interactions included well-developed leg musculature and talons, enhanced flight acceleration and maneuverability, novel fighting behaviors, and traits associated with aggression, such as testosterone and muscle development. Traits that may have hindered larger species in aggressive interactions included the evolution of morphologies for tree trunk foraging that compromised performance in aggressive contests away from trunks, and the evolution of migration. Overall, our results suggest that fundamental trade-offs, such as those associated with body size

  12. When David Beats Goliath: The Advantage of Large Size in Interspecific Aggressive Contests Declines over Evolutionary Time

    PubMed Central

    Martin, Paul R.; Ghalambor, Cameron K.

    2014-01-01

    Body size has long been recognized to play a key role in shaping species interactions. For example, while small species thrive in a diversity of environments, they typically lose aggressive contests for resources with larger species. However, numerous examples exist of smaller species dominating larger species during aggressive interactions, suggesting that the evolution of traits can allow species to overcome the competitive disadvantage of small size. If these traits accumulate as lineages diverge, then the advantage of large size in interspecific aggressive interactions should decline with increased evolutionary distance. We tested this hypothesis using data on the outcomes of 23,362 aggressive interactions among 246 bird species pairs involving vultures at carcasses, hummingbirds at nectar sources, and antbirds and woodcreepers at army ant swarms. We found the advantage of large size declined as species became more evolutionarily divergent, and smaller species were more likely to dominate aggressive contests when interacting with more distantly-related species. These results appear to be caused by both the evolution of traits in smaller species that enhanced their abilities in aggressive contests, and the evolution of traits in larger species that were adaptive for other functions, but compromised their abilities to compete aggressively. Specific traits that may provide advantages to small species in aggressive interactions included well-developed leg musculature and talons, enhanced flight acceleration and maneuverability, novel fighting behaviors, and traits associated with aggression, such as testosterone and muscle development. Traits that may have hindered larger species in aggressive interactions included the evolution of morphologies for tree trunk foraging that compromised performance in aggressive contests away from trunks, and the evolution of migration. Overall, our results suggest that fundamental trade-offs, such as those associated with body size

  13. Detection of Propensity for Aggression based on Facial Structure Irrespective of Face Race

    PubMed Central

    SHORT, LINDSEY A.; MONDLOCH, CATHERINE J.; MCCORMICK, CHERYL M.; CARRÉ, JUSTIN M.; MA, RUQIAN; FU, GENYUE; LEE, KANG

    2011-01-01

    The human face provides a wealth of information pertaining to the internal state and life-stage history of an individual. Facial width-to-height ratio is a size-independent sexually dimorphic trait, and estimates of aggression made by untrained adults judging own-race faces were positively associated with both facial width-to-height ratio and actual aggressive behavior. Given the significant adaptive value of accurately detecting aggressiveness based on facial appearance, we hypothesized that aggression estimates made by adults and 8-year-olds would be highly correlated with male facial width-to-height ratio even for a face category with which they had minimal experience—other-race faces. For each of the four race and age groups, estimates of aggression were positively correlated with facial width-to-height ratio irrespective of rating own-or other-race faces. Overall, the correlations between facial width-to-height ratio and ratings of aggression were stronger for adults than for children. Sensitivity to facial width-to-height ratio appears to be part of an evolved mechanism designed to detect threats in the external environment. This mechanism is likely broadly tuned and functions independently of experience. PMID:22611331

  14. Effect of Polar Environments on the Aluminum Oxide Shell Surrounding Aluminum Particles: Simulations of Surface Hydroxyl Bonding and Charge.

    PubMed

    Padhye, Richa; Aquino, Adelia J A; Tunega, Daniel; Pantoya, Michelle L

    2016-06-01

    Density functional theory (DFT) calculations were performed to understand molecular variations on an alumina surface due to exposure to a polar environment. The analysis has strong implications for the reactivity of aluminum (Al) particles passivated by an alumina shell. Recent studies have shown a link between the carrier fluid used for Al powder intermixing and the reactivity of Al with fluorine containing reactive mixtures. Specifically, flame speeds show a threefold increase when polar liquids are used to intermix aluminum and fluoropolymer powder mixtures. It was hypothesized that the alumina lattice structure could be transformed due to hydrogen bonding forces exerted by the environment that induce modified bond distances and charges and influence reactivity. In this study, the alumina surface was analyzed using DFT calculations and model clusters as isolated systems embedded in polar environments (acetone and water). The conductor-like screening model (COSMO) was used to mimic environmental effects on the alumina surface. Five defect models for specific active -OH sites were investigated in terms of structures and vibrational -OH stretching frequencies. The observed changes of the surface OH sites invoked by the polar environment were compared to the bare surface. The calculations revealed a strong connection between the impact of carrier fluid polarity on the hydrogen bonding forces between the surface OH sites and surrounding species. Changes were observed in the OH characteristic properties such as OH distances (increase), atomic charges (increase), and OH stretching frequencies (decrease); these consequently improve OH surface reactivity. The difference between medium (acetone) and strong (water) polar environments was minimal in the COSMO approximation. PMID:27175545

  15. Quercetin Partially Preserves Development of Osteoblast Phenotype in Fetal Rat Calvaria Cells in an Oxidative Stress Environment.

    PubMed

    Messer, Jonathan G; La, Stephanie; Hopkins, Robin G; Kipp, Deborah E

    2016-12-01

    Studies are needed to improve understanding of the osteoblast antioxidant response, and the balance between oxidative homeostasis and osteoblast differentiation. The flavonol quercetin aglycone (QRC) up-regulates the osteoblast antioxidant response in vitro without suppressing osteoblast phenotype, suggesting that QRC may preserve osteoblast phenotypic development in cells subsequently exposed to oxidative stress, which suppresses osteoblast differentiation. The aims of this study were to assess the extent that QRC pretreatment preserved development of the osteoblast phenotype in cells subsequently cultured with hydrogen peroxide, an oxidative stressor, and to characterize alterations in the osteoblast antioxidant response and in key antioxidant signaling pathways. We hypothesized that pretreatment with QRC would preserve phenotypic development after hydrogen peroxide treatment, suppress the hydrogen peroxide-induced antioxidant response, and that the antioxidant response would involve alterations in Nrf2 and ERK1/2 signaling. Results showed that treating fetal rat calvarial osteoblasts for 4 days (D5-9) with 300 μM hydrogen peroxide resulted in fewer alkaline phosphatase-positive cells and mineralized nodules, altered cell morphology, and significantly lower osteoblast phenotypic gene expression (P < 0.05). This suppression was partially blocked when cells were pretreated 12 h with 20 μM QRC. Hydrogen peroxide also produced sustained up-regulation of heme oxygenase-1 (HO-1) and γ-glutamate cysteine ligase catalytic subunit (GCLC), which was partially blocked in hydrogen peroxide-treated cells that first received QRC pretreatment. The alterations in the antioxidant stress response coincided with alterations in phosphorylated ERK1/2, but not Nrf2. These results suggest that QRC suppresses hydrogen peroxide-induced activation of the antioxidant response, and partially preserves osteoblast phenotypic development. J. Cell. Physiol. 231: 2779-2788, 2016.

  16. Perpetration and Victimization of Intimate Partner Aggression Among Rural Mothers

    PubMed Central

    Schwab Reese, Laura M.; Harland, Karisa; Smithart, Kelsey

    2015-01-01

    Abstract Intimate partner aggression is a leading cause of injury among women of child-bearing age. Research suggests that pregnancy and the postpartum period are times of increased vulnerability to aggression. Since rural women are at an increased risk of intimate partner aggression, research is needed to examine the role of pregnancy and the presence of children on intimate partner aggression among this vulnerable population. The purpose of this study is to examine the association between young children and intimate partner aggression victimization and perpetration among a rural sample. This analysis utilized data from biologic females of child-bearing age from the Keokuk County Rural Health Study, a cohort study of over 1,000 rural families conducted from 1994 to 2011. Crude and adjusted logistic regression was used to determine the relationship between having a young child and experiencing four forms of intimate partner aggression: verbal aggression perpetration, verbal aggression victimization, physical aggression perpetration, and physical aggression victimization. Having young children was significantly associated with increased odds of perpetrating verbal aggression but not victimization of verbal aggression or perpetration and victimization of physical aggression. This significant relationship persisted after adjustment for education, employment, or location of residence but not age or marital status. The increased odds of perpetrating verbal aggression among mothers in a rural area highlight the need for interventions designed for rural parents. One method of reducing intimate partner aggression may be to incorporate intimate partner aggression prevention activities into existing child abuse intervention activities.

  17. Relational Aggression in Middle Childhood: Predictors and Adolescent Outcomes

    ERIC Educational Resources Information Center

    Spieker, Susan J.; Campbell, Susan B.; Vandergrift, Nathan; Pierce, Kim M.; Cauffman, Elizabeth; Susman, Elizabeth J.; Roisman, Glenn I.

    2012-01-01

    This study examined gender differences in the level and developmental course of relational aggression in middle childhood, as well as early predictors and outcomes of relational aggression, after controlling for concurrent physical aggression. Relational (RAgg) and Physical aggression (PAgg) scores for 558 boys and 545 girls at the ages of eight…

  18. Relational Aggression and Academic Performance in Elementary School

    ERIC Educational Resources Information Center

    Risser, Scott D.

    2013-01-01

    To investigate the relationship between relational aggression and school performance, this study examined the relative and combined associations among relational aggression, overt aggression, and victimization and children's academic performance. Additionally this study examined the relative associations among relational and overt aggression and…

  19. The dopaminergic system and aggression in laying hens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The dopaminergic system regulates aggression in humans and other mammals. To investigate if birds with genetic propensity for high and low aggressiveness may exhibit distinctly different aggressive mediation via dopamine (DA) D1 and D2 receptor pathways, two high aggressive (DXL and LGPS) and one lo...

  20. Perceptions of low agency and high sexual openness mediate the relationship between sexualization and sexual aggression.

    PubMed

    Blake, Khandis R; Bastian, Brock; Denson, Thomas F

    2016-09-01

    Researchers have become increasingly interested in the saturation of popular Western culture by female hypersexualization. We provide data showing that men have more sexually aggressive intentions toward women who self-sexualize, and that self-sexualized women are vulnerable to sexual aggression if two qualifying conditions are met. Specifically, if perceivers view self-sexualized women as sexually open and lacking agency (i.e., the ability to influence one's environment), they harbor more sexually aggressive intentions and view women as easier to sexually victimize. In Experiment 1, male participants viewed a photograph of a woman whose self-sexualization was manipulated through revealing versus non-revealing clothing. In subsequent experiments, men and women (Experiment 2) and men only (Experiment 3) viewed a photograph of a woman dressed in non-revealing clothing but depicted as open or closed to sexual activity. Participants rated their perceptions of the woman's agency, then judged how vulnerable she was to sexual aggression (Experiments 1 and 2) or completed a sexually aggressive intentions measure (Experiment 3). Results indicated that both men and women perceived self-sexualized women as more vulnerable to sexual aggression because they assumed those women were highly sexually open and lacked agency. Perceptions of low agency also mediated the relationship between women's perceived sexual openness and men's intentions to sexually aggress. These effects persisted even when we described the self-sexualized woman as possessing highly agentic personality traits and controlled for individual differences related to sexual offending. The current work suggests that perceived agency and sexual openness may inform perpetrator decision-making and that cultural hypersexualization may facilitate sexual aggression. Aggr. Behav. 42:483-497, 2016. © 2016 Wiley Periodicals, Inc. PMID:26848102