Science.gov

Sample records for affective lability scale

  1. Hard exercise, affect lability, and personality among individuals with bulimia nervosa.

    PubMed

    Brownstone, Lisa M; Fitzsimmons-Craft, Ellen E; Wonderlich, Stephen A; Joiner, Thomas E; Le Grange, Daniel; Mitchell, James E; Crow, Scott J; Peterson, Carol B; Crosby, Ross D; Klein, Marjorie H; Bardone-Cone, Anna M

    2013-12-01

    The current study explores the personality traits of compulsivity (e.g., sense of orderliness and duty to perform tasks completely) and restricted expression (e.g., emotion expression difficulties) as potential moderators of the relation between affect lability and frequency of hard exercise episodes in a sample of individuals with bulimic pathology. Participants were 204 adult females recruited in five Midwestern cities who met criteria for threshold or subthreshold bulimia nervosa (BN). Compulsivity was found to significantly moderate the relation between affect lability and number of hard exercise episodes over the past 28 days, such that among those with high compulsivity, level of affect lability was associated with the number of hard exercise episodes; whereas, among those with low compulsivity, affect lability was not associated with the number of hard exercise episodes. The same pattern of findings emerged for restricted expression; however, this finding approached, but did not reach statistical significance. As such, it appears that affect lability is differentially related to hard exercise among individuals with BN depending upon the level of compulsivity and, to a more limited extent, restricted expression. These results suggest that, for individuals with BN with either compulsivity or restricted expression, focusing treatment on increasing flexibility and/or verbal expression of emotions may help in the context of intense, fluctuating affect.

  2. The Interactive Effects of Affect Lability, Negative Urgency, and Sensation Seeking on Young Adult Problematic Drinking

    PubMed Central

    Karyadi, Kenny; Coskunpinar, Ayca; Dir, Allyson L.; Cyders, Melissa A.

    2013-01-01

    Prior studies have suggested that affect lability might reduce the risk for problematic drinking among sensation seekers by compensating for their deficiencies in emotional reactivity and among individuals high on negative urgency by disrupting stable negative emotions. Due to the high prevalence of college drinking, this study examined whether affect lability interacted with sensation seeking and negative urgency to influence college student problematic drinking. 414 college drinkers (mean age: 20, 77% female, and 74% Caucasian) from a US Midwestern University completed self-administered questionnaires online. Consistent with our hypotheses, our results indicated that the effects of sensation seeking and negative urgency on problematic drinking weakened at higher levels of affect lability. These findings emphasize the importance of considering specific emotional contexts in understanding how negative urgency and sensation seeking create risk for problematic drinking among college students. These findings might also help us better understand how to reduce problematic drinking among sensation seekers and individuals high on negative urgency. PMID:24826366

  3. The lateralized processing of affect in emotionally labile extraverts and introverts: central and autonomic effects.

    PubMed

    Smith, B D; Kline, R; Lindgren, K; Ferro, M; Smith, D A; Nespor, A

    1995-02-01

    The purpose of the present study was to better understand both the lateralized hemispheric processing of emotion and the differential neural processing of arousal in extraverts and introverts. We preselected right-handed male and female extraverts and introverts who were high in emotional lability. Each subject was exposed to two positive and two negative emotional stimuli under each of three counterbalanced conditions, including affective, cognitive, and neutral, while EEG and electrodermal activity (EDA) were recorded. Results showed that introverts are more aroused and that extraversion interacts with gender to produce differentiated patterns of lateralized neural activity. In addition, affective conditions produced higher levels of arousal than did cognitive or neutral conditions, particularly in the left hemisphere and under negative as opposed to positive stimuli. Finally, the hemispherically differentiated processing of positive and negative stimuli was affected by the contextual conditions under which they were experienced.

  4. How spatial variation in areal extent and configuration of labile vegetation states affect the riparian bird community in Arctic tundra.

    PubMed

    Henden, John-André; Yoccoz, Nigel G; Ims, Rolf A; Langeland, Knut

    2013-01-01

    The Arctic tundra is currently experiencing an unprecedented combination of climate change, change in grazing pressure by large herbivores and growing human activity. Thickets of tall shrubs represent a conspicuous vegetation state in northern and temperate ecosystems, where it serves important ecological functions, including habitat for wildlife. Thickets are however labile, as tall shrubs respond rapidly to both abiotic and biotic environmental drivers. Our aim was to assess how large-scale spatial variation in willow thicket areal extent, configuration and habitat structure affected bird abundance, occupancy rates and species richness so as to provide an empirical basis for predicting the outcome of environmental change for riparian tundra bird communities. Based on a 4-year count data series, obtained through a large-scale study design in low arctic tundra in northern Norway, statistical hierarchical community models were deployed to assess relations between habitat configuration and bird species occupancy and community richness. We found that species abundance, occupancy and richness were greatly affected by willow areal extent and configuration, habitat features likely to be affected by intense ungulate browsing as well as climate warming. In sum, total species richness was maximized in large and tall willow patches of small to intermediate degree of fragmentation. These community effects were mainly driven by responses in the occupancy rates of species depending on tall willows for foraging and breeding, while species favouring other vegetation states were not affected. In light of the predicted climate driven willow shrub encroachment in riparian tundra habitats, our study predicts that many bird species would increase in abundance, and that the bird community as a whole could become enriched. Conversely, in tundra regions where overabundance of large herbivores leads to decreased areal extent, reduced height and increased fragmentation of willow thickets

  5. How Spatial Variation in Areal Extent and Configuration of Labile Vegetation States Affect the Riparian Bird Community in Arctic Tundra

    PubMed Central

    Henden, John-André; Yoccoz, Nigel G.; Ims, Rolf A.; Langeland, Knut

    2013-01-01

    The Arctic tundra is currently experiencing an unprecedented combination of climate change, change in grazing pressure by large herbivores and growing human activity. Thickets of tall shrubs represent a conspicuous vegetation state in northern and temperate ecosystems, where it serves important ecological functions, including habitat for wildlife. Thickets are however labile, as tall shrubs respond rapidly to both abiotic and biotic environmental drivers. Our aim was to assess how large-scale spatial variation in willow thicket areal extent, configuration and habitat structure affected bird abundance, occupancy rates and species richness so as to provide an empirical basis for predicting the outcome of environmental change for riparian tundra bird communities. Based on a 4-year count data series, obtained through a large-scale study design in low arctic tundra in northern Norway, statistical hierarchical community models were deployed to assess relations between habitat configuration and bird species occupancy and community richness. We found that species abundance, occupancy and richness were greatly affected by willow areal extent and configuration, habitat features likely to be affected by intense ungulate browsing as well as climate warming. In sum, total species richness was maximized in large and tall willow patches of small to intermediate degree of fragmentation. These community effects were mainly driven by responses in the occupancy rates of species depending on tall willows for foraging and breeding, while species favouring other vegetation states were not affected. In light of the predicted climate driven willow shrub encroachment in riparian tundra habitats, our study predicts that many bird species would increase in abundance, and that the bird community as a whole could become enriched. Conversely, in tundra regions where overabundance of large herbivores leads to decreased areal extent, reduced height and increased fragmentation of willow thickets

  6. Factors Affecting Release of Heat-Labile Enterotoxin by Enterotoxigenic Escherichia coli

    PubMed Central

    Kunkel, Steven L.; Robertson, Donald C.

    1979-01-01

    Various conditions affecting the release of heat-labile enterotoxin (LT) by enterotoxigenic Escherichia coli have been examined. The pH of a defined medium containing three amino acids, M-9 salts, and 0.5% glucose decreased to less than 7.0 in early log phase of growth, and no extracellular LT was detected. Adjustment of the pH at 8 h from 6.0 to 8.0 resulted in a concomitant increase in LT activity in culture supernatants. The release of cell-associated LT was significantly reduced by preincubation with protease inhibitors and increased by preincubation with trypsin. Cell-associated LT was not released by pH adjustment of cells grown at 21°C; however, polymyxin B treatment released a toxin species active in only the pigeon erythrocyte lysate (PEL) assay system. As the growth temperature was increased, polymyxin B released toxin species which exhibited both PEL and Y-1 adrenal tumor cell activity. Polymyxin B extracts of enterotoxigenic E. coli in early log phase grown at 37°C possessed only PEL activity, whereas extracts from cells in late-log and stationary phases had biological activity in both assay systems. Also, LT released by pH adjustment from mid-log to stationary phase was active in both PEL and Y-1 adrenal tumor cell assays. Gel electrophoresis of polymyxin B extracts revealed at least three molecular weight species active in either the PEL (22,000 daltons and 30,000 daltons) or both the PEL and the Y-1 adrenal tumor cell assay (72,000 daltons), depending on the growth temperature. These observations may help to explain the chemical and biological heterogeneity of most LT preparations and facilitate purification of LT by increasing the yield of enterotoxin. PMID:37162

  7. A Double Blind Trial of Divalproex Sodium for Affective Lability and Alcohol Use Following Traumatic Brain Injury

    DTIC Science & Technology

    2009-10-01

    to lessen the affective lability in TBI. Carbamazepine may ameliorate agitation and disinhibited behavior as well as depression and manic symptoms...anxiety disorder. They do not present the severity or the same natural courses as do Major Depressive Disorder, Bipolar Illness , or Anxiety Disorder, for...1995 for this indication. Also, it is used in conjunction with lithium or carbamazepine to prevent recurrent manic or depressive episodes during long

  8. From "aisle" to "labile": A hierarchical National Adult Reading Test scale revealed by Mokken scaling.

    PubMed

    McGrory, Sarah; Austin, Elizabeth J; Shenkin, Susan D; Starr, John M; Deary, Ian J

    2015-09-01

    Decline in cognitive ability is a core diagnostic criterion for dementia. Knowing the extent of decline requires a baseline score from which change can be reckoned. In the absence of prior cognitive ability scores, vocabulary-based cognitive tests are used to estimate premorbid cognitive ability. It is important that such tests are short yet informative, to maximize information and practicability. The National Adult Reading Test (NART) is commonly used to estimate premorbid intelligence. People are asked to pronounce 50 words ranging from easy to difficult but whether its words conform to a hierarchy is unknown. Five hundred eighty-seven healthy community-dwelling older people with known age 11 IQ scores completed the NART as part of the Lothian Birth Cohort 1936 study. Mokken analysis was used to explore item responses for unidimensional, ordinal, and hierarchical scales. A strong hierarchical scale ("mini-NART") of 23 of the 50 items was identified. These items are invariantly ordered across all ability levels. The validity of the interpretation of this briefer scale's score as an estimate of premorbid ability was examined using the actual age 11 IQ score. The mini-NART accounted for a similar amount of the variance in age 11 IQ as the full NART (NART = 46.5%, mini-NART = 44.8%). The mini-NART is proposed as a useful short clinical tool to estimate prior cognitive ability. The mini-NART has clinical relevance, comprising highly discriminatory, invariantly ordered items allowing for sensitive measurement, and adaptive testing, reducing test administration time, and patient stress.

  9. The tool of microbial genomics research for interpreting the lability of permafrost carbon and potential greenhouse gas feedbacks at different scales of resolution.

    NASA Astrophysics Data System (ADS)

    Waldrop, M. P.; Machelprang, R.; Hultman, J.; Wickland, K. P.

    2012-12-01

    One quarter of the earth's terrestrial surface is underlain by permafrost, or perennially frozen soils. Permafrost soils contain approximately 25% to 50% of the total global soil carbon pool nearly double the atmospheric carbon (C) reservoir. Decomposition of this C by microorganisms may produce globally significant quantities of both carbon dioxide and methane. These processes provide a positive feedback between climate change and the altered biogeochemistry of northern ecosystems. The fate of carbon residing in thawing permafrost soils depends on a number of physical factors including the thermal properties of soils (which affect heat flow rates), its disturbance regime (controlling changes in physical properties), and hydrologic regime (where soil-water interactions can rapidly thaw permafrost). Yet the mechanism of soil organic matter decomposition and greenhouse gas production operates primarily through the microbial loop: growth, carbon and nutrient mineralization, electron transfer, and enzyme production. We tested whether molecular analysis of microbial communities can be utilized as an indicator of permafrost C lability and potential greenhouse gas production from permafrost soils across multiple temporal and spatial scales. For short term studies of lability we compared rates of C turnover in soil incubations to chemical indices of soil lability, soil enzymes, and the abundance of soil microbial populations. Permafrost soils for the incubation ranged from frozen peatlands to dry uplands and Pleistocene Yedoma. For analysis at the annual to decadal scale, we utilized a permafrost thaw gradient at the Bonanza Creek LTER near Fairbanks Alaska. At this gradient, a Black Spruce forest underlain by permafrost thawed to form a thermokarst bog <50 years ago. Over the short term (months), the lability of permafrost C is reflected in the chemistry of dissolved constituents of permafrost, and it is also reflected in the change in abundance of total soil bacteria

  10. Agricultural management and labile carbon additions affect soil microbial community structure and interact with carbon and nitrogen cycling.

    PubMed

    Berthrong, Sean T; Buckley, Daniel H; Drinkwater, Laurie E

    2013-07-01

    We investigated how conversion from conventional agriculture to organic management affected the structure and biogeochemical function of soil microbial communities. We hypothesized the following. (1) Changing agricultural management practices will alter soil microbial community structure driven by increasing microbial diversity in organic management. (2) Organically managed soil microbial communities will mineralize more N and will also mineralize more N in response to substrate addition than conventionally managed soil communities. (3) Microbial communities under organic management will be more efficient and respire less added C. Soils from organically and conventionally managed agroecosystems were incubated with and without glucose ((13)C) additions at constant soil moisture. We extracted soil genomic DNA before and after incubation for TRFLP community fingerprinting of soil bacteria and fungi. We measured soil C and N pools before and after incubation, and we tracked total C respired and N mineralized at several points during the incubation. Twenty years of organic management altered soil bacterial and fungal community structure compared to continuous conventional management with the bacterial differences caused primarily by a large increase in diversity. Organically managed soils mineralized twice as much NO3 (-) as conventionally managed ones (44 vs. 23 μg N/g soil, respectively) and increased mineralization when labile C was added. There was no difference in respiration, but organically managed soils had larger pools of C suggesting greater efficiency in terms of respiration per unit soil C. These results indicate that the organic management induced a change in community composition resulting in a more diverse community with enhanced activity towards labile substrates and greater capacity to mineralize N.

  11. Biosolids application affects the competitive sorption and lability of cadmium, copper, nickel, lead, and zinc in fluvial and calcareous soils.

    PubMed

    Shaheen, Sabry M; Antoniadis, Vasileios; Kwon, Eilhann E; Biswas, Jayanta K; Wang, Hailong; Ok, Yong Sik; Rinklebe, Jörg

    2017-03-03

    The objective of this research was to investigate the effects of biosolids on the competitive sorption and lability of the sorbed Cd, Cu, Ni, Pb, and Zn in fluvial and calcareous soils. Competitive sorption isotherms were developed, and the lability of these metals was estimated by DTPA extraction following their sorption. Sorption of all metals was higher in the fluvial than in the calcareous soil. Sorption of Cu and Pb was stronger than that of Cd, Ni, and Zn in all soils. Biosolids application (2.5%) reduced the sorption of all metals especially Cu and Pb (28-43%) in both soils (especially the calcareous soil) at the lower added metal concentrations (50 and 100 mg L(-1)). However, it increased the sorption of all metals especially Pb and Cu in both soils (especially the calcareous soil; 15.5-fold for Cu) at the higher added concentrations (250 and 300 mg L(-1)). Nickel showed the highest lability followed by Cd, Zn, and Pb in both soils. Biosolids increased the lability of the sorbed Ni in the fluvial soils at all added concentrations and the lability of Cd, Pb, and Zn at 50 mg L(-1), but decreased the lability of Cd, Pb, and Zn at 250 and 300 mg L(-1) in both soils. We conclude that at low loading rate (e.g., 50 mg L(-1)) biosolids treatment might increase the lability and environmental risk of Cd, Cu, Pb, and Zn. However, at high loading rate (e.g., 300 mg L(-1)) biosolids may be used as an immobilizing agent for Cd, Cu, Pb, Zn and mobilizing agent for Ni.

  12. Conservative whole-organ scaling contrasts with highly labile suborgan scaling differences among compound eyes of closely related Formica ants.

    PubMed

    Perl, Craig D; Rossoni, Sergio; Niven, Jeremy E

    2017-03-01

    Static allometries determine how organ size scales in relation to body mass. The extent to which these allometric relationships are free to evolve, and how they differ among closely related species, has been debated extensively and remains unclear; changes in intercept appear common, but changes in slope are far rarer. Here, we compare the scaling relationships that govern the structure of compound eyes of four closely related ant species from the genus Formica. Comparison among these species revealed changes in intercept but not slope in the allometric scaling relationships governing eye area, facet number, and mean facet diameter. Moreover, the scaling between facet diameter and number was conserved across all four species. In contrast, facet diameters from distinct regions of the compound eye differed in both intercept and slope within a single species and when comparing homologous regions among species. Thus, even when species are conservative in the scaling of whole organs, they can differ substantially in regional scaling within organs. This, at least partly, explains how species can produce organs that adhere to genus wide scaling relationships while still being able to invest differentially in particular regions of organs to produce specific features that match their ecology.

  13. Changes in lead and zinc lability during weathering-induced acidification of desert mine tailings: Coupling chemical and micro-scale analyses

    PubMed Central

    Hayes, Sarah M.; White, Scott A.; Thompson, Thomas L.; Maier, Raina M.; Chorover, Jon

    2009-01-01

    Desert mine tailings may accumulate toxic metals in the near surface centimeters because of low water through-flux rates. Along with other constraints, metal toxicity precludes natural plant colonization even over decadal time scales. Since unconsolidated particles can be subjected to transport by wind and water erosion, potentially resulting in direct human and ecosystem exposure, there is a need to know how the lability and form of metals change in the tailings weathering environment. A combination of chemical extractions, X-ray diffraction, micro-X-ray fluorescence spectroscopy, and micro-Raman spectroscopy were employed to study Pb and Zn contamination in surficial arid mine tailings from the Arizona Klondyke State Superfund Site. Initial site characterization indicated a wide range in pH (2.5 to 8.0) in the surficial tailings pile. Ligand-promoted (DTPA) extractions, used to assess plant-available metal pools, showed decreasing available Zn and Mn with progressive tailings acidification. Aluminum shows the inverse trend, and Pb and Fe show more complex pH dependence. Since the tailings derive from a common source and parent mineralogy, it is presumed that variations in pH and “bioavailable” metal concentrations result from associated variation in particle-scale geochemistry. Four sub-samples, ranging in pH from 2.6 to 5.4, were subjected to further characterization to elucidate micro-scale controls on metal mobility. With acidification, total Pb (ranging from 5 – 13 g kg−1) was increasingly associated with Fe and S in plumbojarosite aggregates. For Zn, both total (0.4 – 6 g kg−1) and labile fractions decreased with decreasing pH. Zinc was found to be primarily associated with the secondary Mn phases manjiroite and chalcophanite. The results suggest that progressive tailings acidification diminishes the overall lability of the total Pb and Zn pools. PMID:20161492

  14. Predicting non-suicidal self-injury episodes over a discrete period of time in a sample of women diagnosed with bulimia nervosa: An analysis of self-reported trait and ecological momentary assessment based affective lability and previous suicide attempts

    PubMed Central

    Anestis, Michael D.; Silva, Caroline; Lavender, Jason M.; Crosby, Ross D.; Wonderlich, Stephen A.; Engel, Scott G.; Joiner, Thomas E.

    2013-01-01

    Objective To examine the moderating effect of trait affective lability on the relationship between past suicidal behavior and future nonsuicidal self-injury (NSSI). Method 127 adult females diagnosed with bulimia nervosa took part in this study. We hypothesized that individuals with greater levels of self-reported trait affective lability and a greater number of past suicide attempts would engage in a greater number of NSSI episodes over the course of two weeks than would individuals lacking elevations in one or both of those variables, controlling for average level of negative affect and affective lability as measured through ecological momentary assessment (EMA). Results The two-way interaction of trait affective lability and past suicidal behavior predicted participants’ number of NSSI episodes during the course of the study. Discussion Interaction of self-reported trait affective lability and past suicidal behavior may exhibit clinical utility in the prediction of patients’ imminent risk of engaging in NSSI. PMID:21744378

  15. Soil respiration, labile carbon pools, and enzyme activities as affected by tillage practices in a tropical rice-maize-cowpea cropping system.

    PubMed

    Neogi, S; Bhattacharyya, P; Roy, K S; Panda, B B; Nayak, A K; Rao, K S; Manna, M C

    2014-07-01

    In order to identify the viable option of tillage practices in rice-maize-cowpea cropping system that could cut down soil carbon dioxide (CO2) emission, sustain grain yield, and maintain better soil quality in tropical low land rice ecology soil respiration in terms of CO2 emission, labile carbon (C) pools, water-stable aggregate C fractions, and enzymatic activities were investigated in a sandy clay loam soil. Soil respiration is the major pathway of gaseous C efflux from terrestrial systems and acts as an important index of ecosystem functioning. The CO2-C emissions were quantified in between plants and rows throughout the year in rice-maize-cowpea cropping sequence both under conventional tillage (CT) and minimum tillage (MT) practices along with soil moisture and temperature. The CO2-C emissions, as a whole, were 24 % higher in between plants than in rows, and were in the range of 23.4-78.1, 37.1-128.1, and 28.6-101.2 mg m(-2) h(-1) under CT and 10.7-60.3, 17.3-99.1, and 17.2-79.1 mg m(-2) h(-1) under MT in rice, maize, and cowpea, respectively. The CO2-C emission was found highest under maize (44 %) followed by rice (33 %) and cowpea (23 %) irrespective of CT and MT practices. In CT system, the CO2-C emission increased significantly by 37.1 % with respect to MT on cumulative annual basis including fallow. The CO2-C emission per unit yield was at par in rice and cowpea signifying the beneficial effect of MT in maintaining soil quality and reduction of CO2 emission. The microbial biomass C (MBC), readily mineralizable C (RMC), water-soluble C (WSC), and permanganate-oxidizable C (PMOC) were 19.4, 20.4, 39.5, and 15.1 % higher under MT than CT. The C contents in soil aggregate fraction were significantly higher in MT than CT. Soil enzymatic activities like, dehydrogenase, fluorescein diacetate, and β-glucosidase were significantly higher by 13.8, 15.4, and 27.4 % under MT compared to CT. The soil labile C pools, enzymatic activities, and

  16. Spanish validation of the Affective Neuroscience Personality Scales.

    PubMed

    Abella, Víctor; Panksepp, Jaak; Manga, Dionisio; Bárcena, Carmen; Iglesias, José A

    2011-11-01

    The Affective Neuroscience Personality Scales have been designed to provide a personality assessment tool based on six distinct affective systems. The six neural systems involved were labeled PLAY, SEEK, CARE, FEAR, ANGER and SADNESS. Spirituality has been integrated into the questionnaire as a seventh dimension because, in opinion of Panksepp and his colleagues is one of the most interesting human emotion. The aim of the present paper was introduce the validation of the Spanish version of Affective Neuroscience Personality Scales and their first psychometric results in a sample of 411 college students. Participants completed the Spanish version of ANPS, just as a personality scale of five factors (NEO-FFI-R), and the Scales of Positive and Negative Affect (PANAS). The factor structure obtained and psychometric properties of the scales indicate that the Spanish version of the scales provides an effective tool to measure the seven dimensions of personality proposal in the original questionnaire.

  17. Measuring Mathematics Anxiety: Psychometric Analysis of a Bidimensional Affective Scale

    ERIC Educational Resources Information Center

    Bai, Haiyan; Wang, LihShing; Pan, Wei; Frey, Mary

    2009-01-01

    The purpose of this study is to develop a theoretically and methodologically sound bidimensional affective scale measuring mathematics anxiety with high psychometric quality. The psychometric properties of a 14-item Mathematics Anxiety Scale-Revised (MAS-R) adapted from Betz's (1978) 10-item Mathematics Anxiety Scale were empirically analyzed on a…

  18. Highly labile elements. [in meteorites

    NASA Technical Reports Server (NTRS)

    Lipschutz, Michael E.; Woolum, Dorothy S.

    1988-01-01

    Certain elements of high lability are very responsive to thermal processes, being either highly volatile during primary nebular condensation or highly mobile by postaccretionary metamorphic or shock heating. Data for highly labile elements indicate that different thermal processes were important in the genesis of each of the chondritic groups and a discussion of each is given. Contents of highly labile elements in a given group of contemporary falls differ from those of the same group that fell in Antarctica more than 0.1 Myr ago. This difference is due either to a time-dependent change in meteorite sources or, less likely, orbital variation of the meteorite flux to Earth.

  19. Gel-based coloration technique for the submillimeter-scale imaging of labile phosphorus in sediments and soils with diffusive gradients in thin films.

    PubMed

    Ding, Shiming; Wang, Yan; Xu, Di; Zhu, Chungang; Zhang, Chaosheng

    2013-07-16

    We report a highly promising technique for the high-resolution imaging of labile phosphorus (P) in sediments and soils in combination with the diffusive gradients in thin films (DGT). This technique was based on the surface coloration of the Zr-oxide binding gel using the conventional molybdenum blue method following the DGT uptake of P to this gel. The accumulated mass of the P in the gel was then measured according to the grayscale intensity on the gel surface using computer-imaging densitometry. A pretreatment of the gel in hot water (85 °C) for 5 d was required to immobilize the phosphate and the formed blue complex in the gel during the color development. The optimal time required for a complete color development was determined to be 45 min. The appropriate volume of the coloring reagent added was 200 times of that of the gel. A calibration equation was established under the optimized conditions, based on which a quantitative measurement of P was obtained when the concentration of P in solutions ranged from 0.04 mg L(-1) to 4.1 mg L(-1) for a 24 h deployment of typical DGT devices at 25 °C. The suitability of the coloration technique was well demonstrated by the observation of small, discrete spots with elevated P concentrations in a sediment profile.

  20. The Development of the Meta-Affective Trait Scale

    ERIC Educational Resources Information Center

    Uzuntiryaki-Kondakci, Esen; Kirbulut, Zubeyde Demet

    2016-01-01

    The purpose of this study was to develop a Meta-Affective Trait Scale (MATS) to measure the meta-affective inclinations related to emotions that students have while they are studying for their classes. First, a pilot study was performed with 380 10th-grade students. Results of the exploratory factor analysis supported a two-factor structure of the…

  1. The Cognitive, Affective, and Somatic Empathy Scales (CASES) for Children.

    PubMed

    Raine, Adrian; Chen, Frances R

    2017-03-20

    Although the assessment of empathy has moved from general empathy to differentiating between cognitive and affective empathy, no instruments have assessed somatic (motor) empathy, and none have separated positive from negative affect empathy. The main objective of this study was to develop a 30-item self-report cognitive, affective, and somatic empathy scale (CASES) with positive and negative affect components for use with children and adolescents. A community sample of 428 male and female 11-year-olds completed the CASES together with validity questionnaires and were assessed on IQ. Caregivers reported on callous-unemotional traits, behavior problems, social adversity, and paternal criminality. Confirmatory factor analysis provided support for a 3-factor cognitive-affective-somatic structure of CASES and support for a broader 6-factor model of empathy. Configural and metric factor invariance across genders was established. Good internal consistency was obtained for the main scales. Criterion validity was established by lower empathy in callous-unemotional children. Incremental and predictive validity was documented by empathy at baseline predicting 12 months later to callous-unemotional traits after controlling for baseline callous-unemotional traits. Discriminant validity was documented by empathy being unrelated to internalizing behavior problems and differentially related to proactive and reactive forms of aggression. Construct validity was documented by lower empathy being associated with lower IQ, being male, more externalizing behavior problems, and criminality in the biological parent. Results provide initial support for a brief but multidimensional empathy scale with good sampling and face validity that can be used with children and adolescents.

  2. Scaling Up Family Therapy in Fragile, Conflict-Affected States.

    PubMed

    Charlés, Laurie L

    2015-09-01

    This article discusses the design and delivery of two international family therapy-focused mental health and psychosocial support training projects, one in a fragile state and one in a post-conflict state. The training projects took place in Southeast Asia and the Middle East/North Africa. Each was funded, supported, and implemented by local, regional, and international stakeholders, and delivered as part of a broader humanitarian agenda to develop human resource capacity to work with families affected by atrocities. The two examples illustrate how task-shifting/task-sharing and transitional justice approaches were used to inform the scaling-up of professionals involved in each project. They also exemplify how state-citizen phenomena in each location affected the project design and delivery.

  3. Scale of Carbon Nanomaterials Affects Neural Outgrowth and Adhesion

    PubMed Central

    Franca, Eric; Jao, PitFee; Fang, Sheng-Po; Alagapan, Sankaraleengam; Pan, Liangbin; Yoon, Jung Hae; Yoon, Yong-Kyu ‘YK’

    2016-01-01

    Carbon nanomaterials have become increasingly popular microelectrode materials for neuroscience applications. Here we study how the scale of carbon nanotubes and carbon nanofibers affect neural viability, outgrowth, and adhesion. Carbon nanotubes were deposited on glass coverslips via a layer-by-layer method with polyethylenimine (PEI). Carbonized nanofibers were fabricated by electrospinning SU-8 and pyrolyzing the nanofiber depositions. Additional substrates tested were carbonized and SU-8 thin films and SU-8 nanofibers. Surfaces were O2-plasma treated, coated with varying concentrations of PEI, seeded with E18 rat cortical cells, and examined at 3, 4, and 7 days in vitro (DIV). Neural adhesion was examined at 4 DIV utilizing a parallel plate flow chamber. At 3 DIV, neural viability was lower on the nanofiber and thin film depositions treated with higher PEI concentrations which corresponded with significantly higher zeta potentials (surface charge); this significance was drastically higher on the nanofibers suggesting that the nanostructure may collect more PEI molecules, causing increased toxicity. At 7 DIV, significantly higher neurite outgrowth was observed on SU-8 nanofiber substrates with nanofibers a significant fraction of a neuron’s size. No differences were detected for carbonized nanofibers or carbon nanotubes. Both carbonized and SU-8 nanofibers had significantly higher cellular adhesion post-flow in comparison to controls whereas the carbon nanotubes were statistically similar to control substrates. These data suggest a neural cell preference for larger-scale nanomaterials with specific surface treatments. These characteristics could be taken advantage of in the future design and fabrication of neural microelectrodes. PMID:26829799

  4. Development of a Behavioral Affective Relationship Scale for Encounter Research.

    ERIC Educational Resources Information Center

    Shadish, William R., Jr.; Zarle, Thomas

    The paper outlines several studies over a two-year period to develop a self-report and observer-rating measure of sensitivity/encounter group outcome. The initial form of the scale was taken from McMillan (1971) who developed a measure of 16 categories of group outcome; McMillan's work indicated the scale had high reliability. Subsequent study…

  5. Scales affect performance of Monarch butterfly forewings in autorotational flight

    NASA Astrophysics Data System (ADS)

    Demko, Anya; Lang, Amy

    2012-11-01

    Butterfly wings are characterized by rows of scales (approximately 100 microns in length) that create a shingle-like pattern of cavities over the entire surface. It is hypothesized that these cavities influence the airflow around the wing and increase aerodynamic performance. A forewing of the Monarch butterfly (Danus plexippus) naturally undergoes autorotational flight in the laminar regime. Autorotational flight is an accurate representation of insect flight because the rotation induces a velocity gradient similar to that found over a flapping wing. Drop test flights of 22 forewings before and after scale removal were recorded with a high-speed camera and flight behavior was quantified. It was found that removing the scales increased the descent speed and decreased the descent factor, a measure of aerodynamic efficacy, suggesting that scales increased the performance of the forewings. Funded by NSF REU Grant 1062611.

  6. Quercetin as a shuttle for labile iron.

    PubMed

    Baccan, Mayara Marinovic; Chiarelli-Neto, Orlando; Pereira, Regina Mara Silva; Espósito, Breno Pannia

    2012-02-01

    The antioxidant activity of flavonoids may involve their ability to complex body iron in non-redox-active forms. In this study, it was found that the catechol flavonoids rutin and quercetin are able to suppress redox-active labile plasma iron (LPI) in both buffered solution and in iron-overloaded sera. Both flavonoids are effective in loading the metal into the iron-transport protein transferrin. Iron derivatives of quercetin and rutin are able to permeate cell membranes, however, only free quercetin is able to gain access to the cytosol and decrease intracellular labile iron pools. These results suggest that the antioxidant activity of quercetin may be dependent on its ability to shuttle labile iron from cell compartments followed by its transfer to transferrin.

  7. Maternal emotion socialization differentially predicts third-grade children's emotion regulation and lability.

    PubMed

    Rogers, Megan L; Halberstadt, Amy G; Castro, Vanessa L; MacCormack, Jennifer K; Garrett-Peters, Patricia

    2016-03-01

    Numerous parental emotion socialization factors have been implicated as direct and indirect contributors to the development of children's emotional competence. To date, however, no study has combined parents' emotion-related beliefs, behaviors, and regulation strategies in one model to assess their cumulative-as well as unique-contributions to children's emotion regulation. We considered the 2 components that have recently been distinguished: emotion regulation and emotional lability. We predicted that mothers' beliefs about the value of and contempt for children's emotions, mothers' supportive and nonsupportive reactions to their children's emotions, as well as mothers' use of cognitive reappraisal and suppression of their own emotions would each contribute unique variance to their children's emotion regulation and lability, as assessed by children's teachers. The study sample consisted of an ethnically and socioeconomically diverse group of 165 mothers and their third-grade children. Different patterns emerged for regulation and lability: Controlling for family income, child gender, and ethnicity, only mothers' lack of suppression as a regulatory strategy predicted greater emotion regulation in children, whereas mothers' valuing of children's emotions, mothers' lack of contempt for children's emotions, mothers' use of cognitive reappraisal to reinterpret events, and mothers' lack of emotional suppression predicted less lability in children. These findings support the divergence of emotion regulation and lability as constructs and indicate that, during middle childhood, children's lability may be substantially and uniquely affected by multiple forms of parental socialization.

  8. Amount and Lability of Dissolved Organic Carbon Entering Arctic Streams from Landscapes Disturbed by Fire and Thermokarst Terrain, North Slope, Alaska

    NASA Astrophysics Data System (ADS)

    Larouche, J. R.; Abbott, B. W.; Jones, J.; Bowden, W. B.

    2011-12-01

    The arctic climate is warming, which will have important impacts on stream ecosystems. In the Alaskan arctic, fire frequency and thermokarst formation (permafrost degradation and collapse) have become more common. Our previous research shows that these processes have important hydrologic and biogeochemical effects on streams including increased export of inorganic nutrients and sediment, both of which alter the metabolism and nutrient dynamics of impacted streams. Another potential impact of thermokarst and fire is the increased delivery of biologically reactive dissolved organic matter (DOM) to streams. We studied how fire and thermokarst formation affect the rate of DOM delivery and the input of labile DOM to streams in arctic Alaska. Recent work in both thermokarst and fire-impacted streams suggest an increase in dissolved organic carbon (DOC) as the summer progresses. We characterized the reactivity of DOC entering streams disturbed by thermokarst and burned conditions. Initial results of DOC decomposition rates suggest that thermokarst waters contain a higher fraction of labile DOC compared to water tracks and headwater streams. During the summer of 2011, we monitored streams at the watershed and individual thermokarst feature scale for inorganic nutrients, sediment, major cations, alkalinity, and DOC concentration and lability. We characterized potential DOC lability by sampling a time series (0, 10, and 40 d) of water samples from common sources that had been inoculated initially with the same microbial community and enriched with nutrients to stimulate maximum decomposition of the DOC. Specific Ultraviolet Absorbance (SUVA) was used to characterize DOC quality as a function of aromaticity. Four of the watersheds we sampled were affected by the 2007 Anaktuvuk River Burn, one of which experienced subsequent thermokarst formation, and two watersheds are reference sites. Determining rates of DOC decomposition and the potential controlling factors from streams

  9. Development and Validation of Children's Environmental Affect (Attitude, Sensitivity and Willingness to Take Action) Scale

    ERIC Educational Resources Information Center

    Erdogan, Mehmet; Marcinkowski, Thomas

    2015-01-01

    This study focuses on the design, development, validation, and psychometric properties of the Children's Environmental Affect Scale (CEAS). The following steps were taken in developing the CEAS. A substantial review of literature on environmental affect and EL helped the researchers identify several scales and questionnaires that, in turn, help…

  10. Effects of carbon substrate lability on carbon mineralization dynamics of tropical peat

    NASA Astrophysics Data System (ADS)

    Jauhiainen, Jyrki; Silvennoinen, Hanna; Könönen, Mari; Limin, Suwido; Vasander, Harri

    2016-04-01

    Extensive draining at tropical ombrotrophic peatlands in Southeast Asia has made them global 'hot spots' for greenhouse gas emissions. Management practises and fires have led to changed substrate status, which affects microbial processes. Here, we present the first data on how management practises affect carbon (C) mineralization processes at these soils. We compared the carbon mineralization potentials of pristine forest soils to those of drained fire affected soils at various depths, with and without additional labile substrates (glucose, glutamate and NO3-N) and in oxic and anoxic conditions by dedicated ex situ experiments. Carbon mineralization (CO2 and CH4 production) rates were higher in the pristine site peat, which contains more labile carbon due to higher input via vegetation. Production rates decreased with depth together with decreasing availability of labile carbon. Consequently, the increase in production rates after labile substrate addition was relatively modest from pristine site as compared to the managed site and from the top layers as compared to deeper layers. Methanogenesis had little importance in total carbon mineralization. Adding labile C and N enhanced heterotrophic CO2 production more than the sole addition of N. Surprisingly, oxygen availability was not an ultimate requirement for substantial CO2 production rates, but anoxic respiration yielded comparable rates, especially at the pristine soils. Flooding of these sites will therefore reduce, but not completely cease, peat carbon loss. Reintroduced substantial vegetation and fertilization in degraded peatlands can enrich recalcitrant peat with simple C and N compounds and thus increase microbiological activity.

  11. Development and validation of brief measures of positive and negative affect: the PANAS scales.

    PubMed

    Watson, D; Clark, L A; Tellegen, A

    1988-06-01

    In recent studies of the structure of affect, positive and negative affect have consistently emerged as two dominant and relatively independent dimensions. A number of mood scales have been created to measure these factors; however, many existing measures are inadequate, showing low reliability or poor convergent or discriminant validity. To fill the need for reliable and valid Positive Affect and Negative Affect scales that are also brief and easy to administer, we developed two 10-item mood scales that comprise the Positive and Negative Affect Schedule (PANAS). The scales are shown to be highly internally consistent, largely uncorrelated, and stable at appropriate levels over a 2-month time period. Normative data and factorial and external evidence of convergent and discriminant validity for the scales are also presented.

  12. How large-scale subsidence affects stratocumulus transitions

    NASA Astrophysics Data System (ADS)

    van der Dussen, J. J.; de Roode, S. R.; Siebesma, A. P.

    2016-01-01

    Some climate modeling results suggest that the Hadley circulation might weaken in a future climate, causing a subsequent reduction in the large-scale subsidence velocity in the subtropics. In this study we analyze the cloud liquid water path (LWP) budget from large-eddy simulation (LES) results of three idealized stratocumulus transition cases, each with a different subsidence rate. As shown in previous studies a reduced subsidence is found to lead to a deeper stratocumulus-topped boundary layer, an enhanced cloud-top entrainment rate and a delay in the transition of stratocumulus clouds into shallow cumulus clouds during its equatorwards advection by the prevailing trade winds. The effect of a reduction of the subsidence rate can be summarized as follows. The initial deepening of the stratocumulus layer is partly counteracted by an enhanced absorption of solar radiation. After some hours the deepening of the boundary layer is accelerated by an enhancement of the entrainment rate. Because this is accompanied by a change in the cloud-base turbulent fluxes of moisture and heat, the net change in the LWP due to changes in the turbulent flux profiles is negligibly small.

  13. Environmental Affective Dispositions Scale (EADS): The Study of Validity and Reliability and Adaptation to Turkish

    ERIC Educational Resources Information Center

    Fettahlioglu, Pinar; Timur, Serkan; Timur, Betül

    2016-01-01

    The aim of this study is to conduct a research under circumstances of Turkey about the validity and reliability of the Affective Tendencies towards Environmental Scale prepared by Yavetz, Goldman and Pe'er (2009). The translation of this scale to Turkish was done by the researchers and language specialists. And then, the scale was evaluated by the…

  14. Scaling preferential flow processes in agricultural soils affected by tillage and trafficking at the field scale

    NASA Astrophysics Data System (ADS)

    Filipović, Vilim; Coquet, Yves

    2016-04-01

    There is an accumulation of experimental evidences that agricultural soils, at least the top horizons affected by tillage practices, are not homogeneous and present a structure that is strongly dependent on farming practices like tillage and trafficking. Soil tillage and trafficking can create compacted zones in the soil with hydraulic properties and porosity which are different from those of the non-compacted zones. This spatial variability can strongly influence transport processes and initiate preferential flow. Two or three dimensional models can be used to account for spatial variability created by agricultural practices, but such models need a detailed assessment of spatial heterogeneity which can be rather impractical to provide. This logically raises the question whether and how one dimensional model may be designed and used to account for the within-field spatial variability in soil structure created by agricultural practices. Preferential flow (dual-permeability) modelling performed with HYDRUS-1D will be confronted to classical modelling based on the Richards and convection-dispersion equations using HYDRUS-2D taking into account the various soil heterogeneities created by agricultural practices. Our goal is to derive one set of equivalent 1D soil hydraulic parameters from 2D simulations which accounts for soil heterogeneities created by agricultural operations. A field experiment was carried out in two phases: infiltration and redistribution on a plot by uniform sprinkle irrigation with water or bromide solution. Prior to the field experiment the soil structure of the tilled layer was determined along the face of a large trench perpendicular to the tillage direction (0.7 m depth and 3.1 m wide). Thirty TDR probes and tensiometers were installed in different soil structural zones (Δ compacted soil and Γ macroporous soil) which ensured soil water monitoring throughout the experiment. A map of bromide was constructed from small core samples (4 cm diam

  15. Black carbon absorption at the global scale is affected by particle-scale diversity in composition

    NASA Astrophysics Data System (ADS)

    Fierce, Laura; Bond, Tami C.; Bauer, Susanne E.; Mena, Francisco; Riemer, Nicole

    2016-09-01

    Atmospheric black carbon (BC) exerts a strong, but uncertain, warming effect on the climate. BC that is coated with non-absorbing material absorbs more strongly than the same amount of BC in an uncoated particle, but the magnitude of this absorption enhancement (Eabs) is not well constrained. Modelling studies and laboratory measurements have found stronger absorption enhancement than has been observed in the atmosphere. Here, using a particle-resolved aerosol model to simulate diverse BC populations, we show that absorption is overestimated by as much as a factor of two if diversity is neglected and population-averaged composition is assumed across all BC-containing particles. If, instead, composition diversity is resolved, we find Eabs=1-1.5 at low relative humidity, consistent with ambient observations. This study offers not only an explanation for the discrepancy between modelled and observed absorption enhancement, but also demonstrates how particle-scale simulations can be used to develop relationships for global-scale models.

  16. Black Carbon Absorption at the Global Scale Is Affected by Particle-Scale Diversity in Composition

    NASA Technical Reports Server (NTRS)

    Fierce, Laura; Bond, Tami C.; Bauer, Susanne E.; Mena, Francisco; Riemer, Nicole

    2016-01-01

    Atmospheric black carbon (BC) exerts a strong, but uncertain, warming effect on the climate. BC that is coated with non-absorbing material absorbs more strongly than the same amount of BC in an uncoated particle, but the magnitude of this absorption enhancement (E(sub abs)) is not well constrained. Modelling studies and laboratory measurements have found stronger absorption enhancement than has been observed in the atmosphere. Here, using a particle-resolved aerosol model to simulate diverse BC populations, we show that absorption is overestimated by as much as a factor of two if diversity is neglected and population-averaged composition is assumed across all BC-containing particles. If, instead, composition diversity is resolved, we find E(sub abs) = 1 - 1.5 at low relative humidity, consistent with ambient observations. This study offers not only an explanation for the discrepancy between modelled and observed absorption enhancement, but also demonstrates how particle-scale simulations can be used to develop relationships for global-scale models.

  17. Black carbon absorption at the global scale is affected by particle-scale diversity in composition

    PubMed Central

    Fierce, Laura; Bond, Tami C.; Bauer, Susanne E.; Mena, Francisco; Riemer, Nicole

    2016-01-01

    Atmospheric black carbon (BC) exerts a strong, but uncertain, warming effect on the climate. BC that is coated with non-absorbing material absorbs more strongly than the same amount of BC in an uncoated particle, but the magnitude of this absorption enhancement (Eabs) is not well constrained. Modelling studies and laboratory measurements have found stronger absorption enhancement than has been observed in the atmosphere. Here, using a particle-resolved aerosol model to simulate diverse BC populations, we show that absorption is overestimated by as much as a factor of two if diversity is neglected and population-averaged composition is assumed across all BC-containing particles. If, instead, composition diversity is resolved, we find Eabs=1−1.5 at low relative humidity, consistent with ambient observations. This study offers not only an explanation for the discrepancy between modelled and observed absorption enhancement, but also demonstrates how particle-scale simulations can be used to develop relationships for global-scale models. PMID:27580627

  18. Biotic and abiotic controls on diurnal fluctuations in labile soil phosphorus of a wet tropical forest.

    PubMed

    Vandecar, Karen L; Lawrence, Deborah; Wood, Tana; Oberbauer, Steven F; Das, Rishiraj; Tully, Katherine; Schwendenmann, Luitgard

    2009-09-01

    The productivity of many tropical wet forests is generally limited by bioavailable phosphorus (P). Microbial activity is a key regulator of P availability in that it determines both the supply of P through organic matter decomposition and the depletion of bioavailable P through microbial uptake. Both microbial uptake and mineralization occur rapidly, and their net effect on P availability varies with soil moisture, temperature, and soil organic matter quantity and quality. Exploring the mechanisms driving P availability at fine temporal scales can provide insight into the coupling of carbon, water, and nutrient cycles, and ultimately, the response of tropical forests to climate change. Despite the recognized importance of P cycling to the dynamics of wet tropical forests and their potential sensitivity to short-term fluctuations in bioavailable P, the diurnal pattern of P remains poorly understood. This study quantifies diurnal fluctuations in labile soil P and evaluates the importance of biotic and abiotic factors in driving these patterns. To this end, measurements of labile P were made every other hour in a Costa Rican wet tropical forest oxisol. Spatial and temporal variation in Bray-extractable P were investigated in relation to ecosystem carbon flux, soil CO2 efflux, soil moisture, soil temperature, solar radiation, and sap-flow velocity. Spatially averaged bi-hourly (every two hours) labile P ranged from 0.88 to 2.48 microg/g across days. The amplitude in labile P throughout the day was 0.61-0.82 microg/g (41-54% of mean P concentrations) and was characterized by a bimodal pattern with a decrease at midday. Labile P increased with soil CO2 efflux and soil temperature and declined with increasing sap flow and solar radiation. Together, soil CO2 efflux, soil temperature, and sap flow explained 86% of variation in labile P.

  19. Large-scale climatic anomalies affect marine predator foraging behaviour and demography.

    PubMed

    Bost, Charles A; Cotté, Cedric; Terray, Pascal; Barbraud, Christophe; Bon, Cécile; Delord, Karine; Gimenez, Olivier; Handrich, Yves; Naito, Yasuhiko; Guinet, Christophe; Weimerskirch, Henri

    2015-10-27

    Determining the links between the behavioural and population responses of wild species to environmental variations is critical for understanding the impact of climate variability on ecosystems. Using long-term data sets, we show how large-scale climatic anomalies in the Southern Hemisphere affect the foraging behaviour and population dynamics of a key marine predator, the king penguin. When large-scale subtropical dipole events occur simultaneously in both subtropical Southern Indian and Atlantic Oceans, they generate tropical anomalies that shift the foraging zone southward. Consequently the distances that penguins foraged from the colony and their feeding depths increased and the population size decreased. This represents an example of a robust and fast impact of large-scale climatic anomalies affecting a marine predator through changes in its at-sea behaviour and demography, despite lack of information on prey availability. Our results highlight a possible behavioural mechanism through which climate variability may affect population processes.

  20. Large-scale climatic anomalies affect marine predator foraging behaviour and demography

    NASA Astrophysics Data System (ADS)

    Bost, Charles A.; Cotté, Cedric; Terray, Pascal; Barbraud, Christophe; Bon, Cécile; Delord, Karine; Gimenez, Olivier; Handrich, Yves; Naito, Yasuhiko; Guinet, Christophe; Weimerskirch, Henri

    2015-10-01

    Determining the links between the behavioural and population responses of wild species to environmental variations is critical for understanding the impact of climate variability on ecosystems. Using long-term data sets, we show how large-scale climatic anomalies in the Southern Hemisphere affect the foraging behaviour and population dynamics of a key marine predator, the king penguin. When large-scale subtropical dipole events occur simultaneously in both subtropical Southern Indian and Atlantic Oceans, they generate tropical anomalies that shift the foraging zone southward. Consequently the distances that penguins foraged from the colony and their feeding depths increased and the population size decreased. This represents an example of a robust and fast impact of large-scale climatic anomalies affecting a marine predator through changes in its at-sea behaviour and demography, despite lack of information on prey availability. Our results highlight a possible behavioural mechanism through which climate variability may affect population processes.

  1. Scale-dependent factors affecting North American river otter distribution in the midwest

    USGS Publications Warehouse

    Jeffress, Mackenzie R.; Paukert, C.P.; Whittier, Joanna B.; Sandercock, B.K.; Gipson, P.S.

    2011-01-01

    The North American river otter (Lontra canadensis) is recovering from near extirpation throughout much of its range. Although reintroductions, trapping regulations and habitat improvements have led to the reestablishment of river otters in the Midwest, little is known about how their distribution is influenced by local- and landscape-scale habitat. We conducted river otter sign surveys from Jan. to Apr. in 2008 and 2009 in eastern Kansas to assess how local- and landscape-scale habitat factors affect river otter occupancy. We surveyed three to nine 400-m stretches of stream and reservoir shorelines for 110 sites and measured local-scale variables (e.g., stream order, land cover types) within a 100 m buffer of the survey site and landscape-scale variables (e.g., road density, land cover types) for Hydrological Unit Code 14 watersheds. We then used occupancy models that account for the probability of detection to estimate occupancy as a function of these covariates using Program PRESENCE. The best-fitting model indicated river otter occupancy increased with the proportion of woodland cover and decreased with the proportion of cropland and grassland cover at the local scale. Occupancy also increased with decreased shoreline diversity, waterbody density and stream density at the landscape scale. Occupancy was not affected by land cover or human disturbance at the landscape scale. Understanding the factors and scale important to river otter occurrence will be useful in identifying areas for management and continued restoration. ?? 2011, American Midland Naturalist.

  2. Assessing Preschool Children's Pretend Play: Preliminary Validation of the Affect in Play Scale-Preschool Version

    ERIC Educational Resources Information Center

    Kaugars, Astrida Seja; Russ, Sandra W.

    2009-01-01

    Research Findings: A description of the development and preliminary validation of the Affect in Play Scale-Preschool version (APS-P) is presented by demonstrating associations among preschool children's play, creativity, and daily behavior using multiple methodologies. Thirty-three preschool-age children completed a standardized 5-minute play task…

  3. Lability of Secondary Organic Particulate Matter

    SciTech Connect

    Liu, Pengfei; Li, Yong Jie; Wang, Yan; Giles, Mary K.; Zaveri, Rahul A.; Bertram, Allan K.; Martin, Scot T.

    2016-10-24

    Accurate simulations of the consenctrations of atmospheric organic particulate matter (PM) are needed for predicting energy flow in the Earth’s climate system. In the past, simulations of organic PM widely assume equilibrium partitioning of semivolatile organic compounds (SVOCs) between the PM and surrounding vapor. Herein, we test this assumption by measuring evaporation rates and associated vapor mass concentration of organic films representative of atmospheric PM. For films representing anthropogenic PM, evaporation rates and vapor mass concentrations increased above a threshold relative humidity (RH), indicating equilibrium partitioning above a transition RH but not below. In contrast for films representing biogenic PM, no threshold was observed, indicating equilibrium partitioning at all RHs. The results suggest that the mass lability of atmospheric organic PM can differ in consequential ways among Earth’s natural biomes, polluted regions, and regions of land-use change, and these differences need to be considered when simulating atmospheric organic PM.

  4. Effects of wetland recovery on soil labile carbon and nitrogen in the Sanjiang Plain.

    PubMed

    Huang, Jingyu; Song, Changchun; Nkrumah, Philip Nti

    2013-07-01

    Soil management significantly affects the soil labile organic factors. Understanding carbon and nitrogen dynamics is extremely helpful in conducting research on active carbon and nitrogen components for different kinds of soil management. In this paper, we examined the changes in microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), dissolved organic carbon (DOC), and dissolved organic nitrogen (DON) to assess the effect and mechanisms of land types, organic input, soil respiration, microbial species, and vegetation recovery under Deyeuxia angustifolia freshwater marshes (DAMs) and recovered freshwater marsh (RFM) in the Sanjiang Plain, Northeast China. Identifying the relationship among the dynamics of labile carbon, nitrogen, and soil qualification mechanism using different land management practices is therefore important. Cultivation and land use affect intensely the DOC, DON, MBC, and MBN in the soil. After DAM soil tillage, the DOC, DON, MBC, and MBN at the surface of the agricultural soil layer declined significantly. In contrast, their recovery was significant in the RFM surface soil. A long time was needed for the concentration of cultivated soil total organic carbon and total nitrogen to be restored to the wetland level. The labile carbon and nitrogen fractions can reach a level similar to that of the wetland within a short time. Typical wetland ecosystem signs, such as vegetation, microbes, and animals, can be recovered by soil labile carbon and nitrogen fraction restoration. In this paper, the D. angustifolia biomass attained natural wetland level after 8 years, indicating that wetland soil labile fractions can support wetland eco-function in a short period of time (4 to 8 years) for reconstructed wetland under suitable environmental conditions.

  5. Fate and lability of silver in soils: Effect of ageing

    EPA Science Inventory

    The fate and lability of added soluble Ag in soils over time was examined by measurement of labile metal (E-value) by isotopic dilution using the 110mAg radioactive isotope and the solid-phase speciation of Ag by X-ray absorption near edge structure (XANES) spectrosco...

  6. THE ASSAY AND PROPERTIES OF LABILE FACTOR (FACTOR V)

    PubMed Central

    Quick, Armand J.

    1960-01-01

    Human oxalated plasma stored at 4° C. until the prothrombin time is increased beyond 60 sec. is a reliable medium for assaying labile factor (factor V) because its response to added labile factor corresponds quantitatively to that of plasma from patients with congenital deficiency of this factor. Such an agreement is not obtained with plasma stored at 37°C. The stability of labile factor is closely associated with ionized calcium. The addition of thrombin to fresh oxalated plasma causes an apparent hyperactivity of labile factor, but this is completely removed by adsorption with Ca3(PO)2. Oxalated plasma when adsorbed with Ca3(PO4)2 before treatment with thrombin does not develop this adventitious activity, nor does it occur in stored plasma treated with thrombin. The seemingly high labile factor activity in serum can be explained by the activation of this factor which is independent of labile factor but acts synergistically with it. The true labile factor concentration can be determined only after the accelerator is removed by adsorption with Ca3(PO4)2. A close agreement between the consumption of prothrombin and the loss of labile factor during clotting is observed. PMID:13738700

  7. Measuring natural pest suppression at different spatial scales affects the importance of local variables.

    PubMed

    Bennett, A B; Gratton, C

    2012-10-01

    The role biodiversity plays in the provision of ecosystem services is widely recognized, yet few ecological studies have identified characteristics of natural systems that support and maintain ecosystem services. The purpose of this study was to identify landscape variables correlated with natural pest suppression carried out by arthropod natural enemies, predators and parasitoids. We conducted two field experiments, one observational and one experimental, where landscape variables at broad and local scales were measured and related to natural pest suppression. The first experiment measured natural pest suppression at 16 sites across an urban to rural landscape gradient in south central Wisconsin. We found natural enemy diversity positively affected natural pest suppression, whereas flower diversity negatively affected pest suppression. No relationship was found between natural pest suppression and broad scale variables, which measured the percentage of different land cover classes in the surrounding landscape. In the second experiment, we established small (2- by 3-m) replicated plots that experimentally varied flower diversity (0, 1, or 7 species) within a plot. We found no significant relationship between natural pest suppression and the different levels of flower diversity. The fact that we only found differences in natural pest suppression in our first experiment, which measured natural pest suppression at sites separated by larger distances than our second experiment, suggests the more appropriate scale for measuring ecosystem services performed by mobile organisms like insects, is across broad spatial scales where variation in natural enemies communities and the factors that affect them become more apparent.

  8. Functional connectivity in the resting brain as biological correlate of the Affective Neuroscience Personality Scales.

    PubMed

    Deris, Nadja; Montag, Christian; Reuter, Martin; Weber, Bernd; Markett, Sebastian

    2017-02-15

    According to Jaak Panksepp's Affective Neuroscience Theory and the derived self-report measure, the Affective Neuroscience Personality Scales (ANPS), differences in the responsiveness of primary emotional systems form the basis of human personality. In order to investigate neuronal correlates of personality, the underlying neuronal circuits of the primary emotional systems were analyzed in the present fMRI-study by associating the ANPS to functional connectivity in the resting brain. N=120 healthy participants were invited for the present study. The results were reinvestigated in an independent, smaller sample of N=52 participants. A seed-based whole brain approach was conducted with seed-regions bilaterally in the basolateral and superficial amygdalae. The selection of seed-regions was based on meta-analytic data on affective processing and the Juelich histological atlas. Multiple regression analyses on the functional connectivity maps revealed associations with the SADNESS-scale in both samples. Functional resting-state connectivity between the left basolateral amygdala and a cluster in the postcentral gyrus, and between the right basolateral amygdala and clusters in the superior parietal lobe and subgyral in the parietal lobe was associated with SADNESS. No other ANPS-scale revealed replicable results. The present findings give first insights into the neuronal basis of the SADNESS-scale of the ANPS and support the idea of underlying neuronal circuits. In combination with previous research on genetic associations of the ANPS functional resting-state connectivity is discussed as a possible endophenotype of personality.

  9. Preservation of labile organic matter in soils of drained thaw lakes in Northern Alaska

    NASA Astrophysics Data System (ADS)

    Mueller, Carsten W.; Rethemeyer, Janet; Kao-Kniffin, Jenny; Löppmann, Sebastian; Hinkel, Kenneth; Bockheim, James

    2014-05-01

    A large number of studies predict changing organic matter (OM) dynamics in arctic soils due to global warming. In contrast to rather slowly altering bulk soil properties, single soil organic matter (SOM) fractions can provide a more detailed picture of the dynamics of differently preserved SOM pools in climate sensitive arctic regions. By the study of the chemical composition of such distinctive SOM fractions using nuclear magnetic resonance spectroscopy (NMR) together with radiocarbon analyses it is possible to evaluate the stability of the major OM pools. Approximately 50-75% of Alaska's Arctic Coastal Plain is covered with thaw lakes and drained thaw lakes that follow a 5,000 yr cycle of development (between creation and final drainage), thus forming a natural soil chronosequence. The drained thaw lakes offer the possibility to study SOM dynamics affected by permafrost processes over millennial timescales. In April 2010 we sampled 16 soil cores (including the active and permanent layer) reaching from young drained lakes (0-50 years since drainage) to ancient drained lakes (3000-5500 years since drainage). Air dried soil samples from soil horizons of the active and permanent layer were subjected to density fractionation in order to differentiate particulate OM and mineral associated OM. The chemical composition of the SOM fractions was analyzed by 13C CPMAS NMR spectroscopy. For a soil core of a young and an ancient drained thaw lake basin we also analyzed the 14C content. For the studied soils we can show that up to over 25 kg OC per square meter are stored mostly as labile, easily degradable organic matter rich in carbohydrates. In contrast only 10 kg OC per square meter were sequestered as presumably more stable mineral associated OC dominated by aliphatic compounds. Comparable to soils of temperate regions, we found small POM (< 20 µm) occluded in aggregated soil structures which differed in the chemical composition from larger organic particles. This was

  10. Protein degradation by ubiquitin–proteasome system in formation and labilization of contextual conditioning memory

    PubMed Central

    Sol Fustiñana, María; de la Fuente, Verónica; Federman, Noel; Freudenthal, Ramiro

    2014-01-01

    The ubiquitin–proteasome system (UPS) of protein degradation has been evaluated in different forms of neural plasticity and memory. The role of UPS in such processes is controversial. Several results support the idea that the activation of this system in memory consolidation is necessary to overcome negative constrains for plasticity. In this case, the inhibition of the UPS during consolidation impairs memory. Similar results were reported for memory reconsolidation. However, in other cases, the inhibition of UPS had no effect on memory consolidation and reconsolidation but impedes the amnesic action of protein synthesis inhibition after retrieval. The last finding suggests a specific action of the UPS inhibitor on memory labilization. However, another interpretation is possible in terms of the synthesis/degradation balance of positive and negative elements in neural plasticity, as was found in the case of long-term potentiation. To evaluate these alternative interpretations, other reconsolidation-interfering drugs than translation inhibitors should be tested. Here we analyzed initially the UPS inhibitor effect in contextual conditioning in crabs. We found that UPS inhibition during consolidation impaired long-term memory. In contrast, UPS inhibition did not affect memory reconsolidation after contextual retrieval but, in fact, impeded memory labilization, blocking the action of drugs that does not affect directly the protein synthesis. To extend these finding to vertebrates, we performed similar experiments in contextual fear memory in mice. We found that the UPS inhibitor in hippocampus affected memory consolidation and blocked memory labilization after retrieval. These findings exclude alternative interpretations to the requirement of UPS in memory labilization and give evidence of this mechanism in both vertebrates and invertebrates. PMID:25135196

  11. Protein degradation by ubiquitin-proteasome system in formation and labilization of contextual conditioning memory.

    PubMed

    Sol Fustiñana, María; de la Fuente, Verónica; Federman, Noel; Freudenthal, Ramiro; Romano, Arturo

    2014-09-01

    The ubiquitin-proteasome system (UPS) of protein degradation has been evaluated in different forms of neural plasticity and memory. The role of UPS in such processes is controversial. Several results support the idea that the activation of this system in memory consolidation is necessary to overcome negative constrains for plasticity. In this case, the inhibition of the UPS during consolidation impairs memory. Similar results were reported for memory reconsolidation. However, in other cases, the inhibition of UPS had no effect on memory consolidation and reconsolidation but impedes the amnesic action of protein synthesis inhibition after retrieval. The last finding suggests a specific action of the UPS inhibitor on memory labilization. However, another interpretation is possible in terms of the synthesis/degradation balance of positive and negative elements in neural plasticity, as was found in the case of long-term potentiation. To evaluate these alternative interpretations, other reconsolidation-interfering drugs than translation inhibitors should be tested. Here we analyzed initially the UPS inhibitor effect in contextual conditioning in crabs. We found that UPS inhibition during consolidation impaired long-term memory. In contrast, UPS inhibition did not affect memory reconsolidation after contextual retrieval but, in fact, impeded memory labilization, blocking the action of drugs that does not affect directly the protein synthesis. To extend these finding to vertebrates, we performed similar experiments in contextual fear memory in mice. We found that the UPS inhibitor in hippocampus affected memory consolidation and blocked memory labilization after retrieval. These findings exclude alternative interpretations to the requirement of UPS in memory labilization and give evidence of this mechanism in both vertebrates and invertebrates.

  12. Scale-dependency of effective hydraulic conductivity on fire-affected hillslopes

    NASA Astrophysics Data System (ADS)

    Langhans, Christoph; Lane, Patrick N. J.; Nyman, Petter; Noske, Philip J.; Cawson, Jane G.; Oono, Akiko; Sheridan, Gary J.

    2016-07-01

    Effective hydraulic conductivity (Ke) for Hortonian overland flow modeling has been defined as a function of rainfall intensity and runon infiltration assuming a distribution of saturated hydraulic conductivities (Ks). But surface boundary condition during infiltration and its interactions with the distribution of Ks are not well represented in models. As a result, the mean value of the Ks distribution (KS¯), which is the central parameter for Ke, varies between scales. Here we quantify this discrepancy with a large infiltration data set comprising four different methods and scales from fire-affected hillslopes in SE Australia using a relatively simple yet widely used conceptual model of Ke. Ponded disk (0.002 m2) and ring infiltrometers (0.07 m2) were used at the small scales and rainfall simulations (3 m2) and small catchments (ca 3000 m2) at the larger scales. We compared KS¯ between methods measured at the same time and place. Disk and ring infiltrometer measurements had on average 4.8 times higher values of KS¯ than rainfall simulations and catchment-scale estimates. Furthermore, the distribution of Ks was not clearly log-normal and scale-independent, as supposed in the conceptual model. In our interpretation, water repellency and preferential flow paths increase the variance of the measured distribution of Ks and bias ponding toward areas of very low Ks during rainfall simulations and small catchment runoff events while areas with high preferential flow capacity remain water supply-limited more than the conceptual model of Ke predicts. The study highlights problems in the current theory of scaling runoff generation.

  13. The brain's emotional foundations of human personality and the Affective Neuroscience Personality Scales.

    PubMed

    Davis, Kenneth L; Panksepp, Jaak

    2011-10-01

    Six of the primary-process subcortical brain emotion systems - SEEKING, RAGE, FEAR, CARE, GRIEF and PLAY - are presented as foundational for human personality development, and hence as a potentially novel template for personality assessment as in the Affective Neurosciences Personality Scales (ANPS), described here. The ANPS was conceptualized as a potential clinical research tool, which would help experimentalists and clinicians situate subjects and clients in primary-process affective space. These emotion systems are reviewed in the context of a multi-tiered framing of consciousness spanning from primary affect, which encodes biological valences, to higher level tertiary (thought mediated) processing. Supporting neuroscience research is presented along with comparisons to Cloninger's Temperament and Character Inventory and the Five Factor Model (FFM). Suggestions are made for grounding the internal structure of the FFM on the primal emotional systems recognized in affective neuroscience, which may promote substantive dialog between human and animal research traditions. Personality is viewed in the context of Darwinian "continuity" with the inherited subcortical brain emotion systems being foundational, providing major forces for personality development in both humans and animals, and providing an affective infrastructure for an expanded five factor descriptive model applying to normal and clinical human populations as well as mammals generally. Links with ontogenetic and epigenetic models of personality development are also presented. Potential novel clinical applications of the CARE maternal-nurturance system and the PLAY system are also discussed.

  14. Flocculated meltwater particles control Arctic land-sea fluxes of labile iron

    PubMed Central

    Markussen, Thor Nygaard; Elberling, Bo; Winter, Christian; Andersen, Thorbjørn Joest

    2016-01-01

    Glacial meltwater systems supply the Arctic coastal ocean with large volumes of sediment and potentially bioavailable forms of iron, nitrogen and carbon. The particulate fraction of this supply is significant but estuarine losses have been thought to limit the iron supply from land. Here, our results reveal how flocculation (particle aggregation) involving labile iron may increase horizontal transport rather than enhance deposition close to the source. This is shown by combining field observations in Disko Fjord, West Greenland, and laboratory experiments. Our data show how labile iron affects floc sizes, shapes and densities and consequently yields low settling velocities and extended sediment plumes. We highlight the importance of understanding the flocculation mechanisms when examining fluxes of meltwater transported iron in polar regions today and in the future, and we underline the influence of terrestrial hotspots on the nutrient and solute cycles in Arctic coastal waters. PMID:27050673

  15. Flocculated meltwater particles control Arctic land-sea fluxes of labile iron

    NASA Astrophysics Data System (ADS)

    Markussen, Thor Nygaard; Elberling, Bo; Winter, Christian; Andersen, Thorbjørn Joest

    2016-04-01

    Glacial meltwater systems supply the Arctic coastal ocean with large volumes of sediment and potentially bioavailable forms of iron, nitrogen and carbon. The particulate fraction of this supply is significant but estuarine losses have been thought to limit the iron supply from land. Here, our results reveal how flocculation (particle aggregation) involving labile iron may increase horizontal transport rather than enhance deposition close to the source. This is shown by combining field observations in Disko Fjord, West Greenland, and laboratory experiments. Our data show how labile iron affects floc sizes, shapes and densities and consequently yields low settling velocities and extended sediment plumes. We highlight the importance of understanding the flocculation mechanisms when examining fluxes of meltwater transported iron in polar regions today and in the future, and we underline the influence of terrestrial hotspots on the nutrient and solute cycles in Arctic coastal waters.

  16. [Pathogen inactivation in labile blood products: transfusion safety and economic impact].

    PubMed

    Cazenave, Jean-Pierre

    2006-01-01

    The safety of labile blood products (red blood cell concentrates, platelet concentrates and plasma) is currently ensured by medical and biological donor selection measures. Nonetheless, in addition to the residual risk of bacterial injection of platelet concentrates and parasitic infection of red cell concentrates, there is the emerging danger associated with new viruses. Pathogen inactivation based on chemical or photochemical genomic modifications is a broad-spectrum approach. These techniques are already used to inactivate plasma, and are being developed or application to platelet and erythrocyte concentrates. Universal inactivation of all labile blood products should be possible in a few years' time, but clinical and hemovigilance studies must first show that the biological properties and therapeutic efficacy of these products are not markedly affected, and that the methods used do not lead to long-term toxicity.

  17. Flocculated meltwater particles control Arctic land-sea fluxes of labile iron.

    PubMed

    Markussen, Thor Nygaard; Elberling, Bo; Winter, Christian; Andersen, Thorbjørn Joest

    2016-04-06

    Glacial meltwater systems supply the Arctic coastal ocean with large volumes of sediment and potentially bioavailable forms of iron, nitrogen and carbon. The particulate fraction of this supply is significant but estuarine losses have been thought to limit the iron supply from land. Here, our results reveal how flocculation (particle aggregation) involving labile iron may increase horizontal transport rather than enhance deposition close to the source. This is shown by combining field observations in Disko Fjord, West Greenland, and laboratory experiments. Our data show how labile iron affects floc sizes, shapes and densities and consequently yields low settling velocities and extended sediment plumes. We highlight the importance of understanding the flocculation mechanisms when examining fluxes of meltwater transported iron in polar regions today and in the future, and we underline the influence of terrestrial hotspots on the nutrient and solute cycles in Arctic coastal waters.

  18. Why is firefly oxyluciferin a notoriously labile substance?

    PubMed

    Maltsev, Oleg V; Nath, Naba K; Naumov, Panče; Hintermann, Lukas

    2014-01-13

    The chemistry of firefly bioluminescence is important for numerous applications in biochemistry and analytical chemistry. The emitter of this bioluminescent system, firefly oxyluciferin, is difficult to handle. The cause of its lability was clarified while its synthesis was reinvestigated. A side product was identified and characterized by NMR spectroscopy and X-ray crystallography. The reason for the lability of oxyluciferin is now ascribed to autodimerization of the coexisting enol and keto forms in a Mannich-type reaction.

  19. Metabolically Labile Fumarate Esters Impart Kinetic Selectivity to Irreversible Inhibitors.

    PubMed

    Zaro, Balyn W; Whitby, Landon R; Lum, Kenneth M; Cravatt, Benjamin F

    2016-12-14

    Electrophilic small molecules are an important class of chemical probes and drugs that produce biological effects by irreversibly modifying proteins. Examples of electrophilic drugs include covalent kinase inhibitors that are used to treat cancer and the multiple sclerosis drug dimethyl fumarate. Optimized covalent drugs typically inactivate their protein targets rapidly in cells, but ensuing time-dependent, off-target protein modification can erode selectivity and diminish the utility of reactive small molecules as chemical probes and therapeutics. Here, we describe an approach to confer kinetic selectivity to electrophilic drugs. We show that an analogue of the covalent Bruton's tyrosine kinase (BTK) inhibitor Ibrutinib bearing a fumarate ester electrophile is vulnerable to enzymatic metabolism on a time-scale that preserves rapid and sustained BTK inhibition, while thwarting more slowly accumulating off-target reactivity in cell and animal models. These findings demonstrate that metabolically labile electrophilic groups can endow covalent drugs with kinetic selectivity to enable perturbation of proteins and biochemical pathways with greater precision.

  20. Spatial scale affects community concordance among fishes, benthic macroinvertebrates, and bryophytes in streams.

    PubMed

    Paavola, Riku; Muotka, Timo; Virtanen, Risto; Heino, Jani; Jackson, Donald; Maki-Petäys, Aki

    2006-02-01

    Owing to the lack of information about the distribution patterns of many taxonomic groups, biodiversity conservation strategies commonly rely on a surrogate taxa approach for identifying areas of maximum conservation potential. Macroinvertebrates or fish are the most likely candidates for such a role in many freshwater systems. The usefulness of the surrogate taxa depends largely on community concordance, i.e., the degree of similarity in community patterns among taxonomic groups across a set of sites. We examined the effect of the spatial scale of a. study on the strength of community concordance among macroinvertebrates, bryophytes, and fish by comparing the concordance between ordinations of these groups in 101 boreal stream sites. We specifically asked if communities spanning several drainages are more concordant than those originating from a single drainage system. Our results indicate that community concordance is affected by spatial extent, being variable and generally weak at the scale of individual drainages, but strong across multiple drainage systems and ecoregions. We attribute this finding to different taxonomic groups responding to similar environmental factors and sharing a similar latitudinal gradient of community structure when viewed across large spatial scales. We also identified a "gradient of concordance," with sites contributing disproportionately to community concordance being in relatively large streams with high microhabitat variability. Overall, our results suggest that the degree of community concordance among freshwater organism groups depends critically on the spatial extent of the study, and surrogate groups at the scale of single river systems should be used with caution.

  1. Biases for affective versus sexual content in multidimensional scaling analysis: an individual difference perspective.

    PubMed

    Prause, Nicole; Moholy, Maxwell; Staley, Cameron

    2014-04-01

    Visual sexual stimuli can motivate sexual behaviors that can risk or enhance health. How one allocates attention to a sexually motivating stimulus may be important for predicting its effect on sexual feelings, sexual risk behaviors, and sexual problems. A large sample (N = 157) of men and women rated the similarity of all possible pairs of photographs of women, which had been pretested to vary in their sexual and affective content. Multidimensional scaling was used to extract two dimensions of sex and affect, including the extent to which each person relied on each dimension in making their similarity judgments. These individual weights were then used to predict sexual variables of interest. Participants who relied more on the affect information judging photograph similarity were more likely to be female, viewed erotica less frequently, reported fewer sexual partners, reported less sexual desire, and more sexual problems. Those who relied more on the erotic content in making their similarity judgments were more likely to be male, viewed more erotica weekly, experienced higher sexual desire, and were more likely to have taken an HIV test. The "double edge sword" of attention weight to affect in sexual cues is discussed for its potential to both enhance and harm sexual health.

  2. The Affective Slider: A Digital Self-Assessment Scale for the Measurement of Human Emotions

    PubMed Central

    Betella, Alberto; Verschure, Paul F. M. J.

    2016-01-01

    Self-assessment methods are broadly employed in emotion research for the collection of subjective affective ratings. The Self-Assessment Manikin (SAM), a pictorial scale developed in the eighties for the measurement of pleasure, arousal, and dominance, is still among the most popular self-reporting tools, despite having been conceived upon design principles which are today obsolete. By leveraging on state-of-the-art user interfaces and metacommunicative pictorial representations, we developed the Affective Slider (AS), a digital self-reporting tool composed of two slider controls for the quick assessment of pleasure and arousal. To empirically validate the AS, we conducted a systematic comparison between AS and SAM in a task involving the emotional assessment of a series of images taken from the International Affective Picture System (IAPS), a database composed of pictures representing a wide range of semantic categories often used as a benchmark in psychological studies. Our results show that the AS is equivalent to SAM in the self-assessment of pleasure and arousal, with two added advantages: the AS does not require written instructions and it can be easily reproduced in latest-generation digital devices, including smartphones and tablets. Moreover, we compared new and normative IAPS ratings and found a general drop in reported arousal of pictorial stimuli. Not only do our results demonstrate that legacy scales for the self-report of affect can be replaced with new measurement tools developed in accordance to modern design principles, but also that standardized sets of stimuli which are widely adopted in research on human emotion are not as effective as they were in the past due to a general desensitization towards highly arousing content. PMID:26849361

  3. The Situational Self-Statement and Affective State Inventory: A Research Scale to Assess Cognitions and Affects.

    ERIC Educational Resources Information Center

    Harrell, Thomas H.; Chambless, Dianne L.

    This paper describes the development, utility, and validity of the Situational Self-statement and Affective State Inventory (SSASI), a research inventory designed to assess cognitions and affects across a variety of five hypothetical situations. Each situation describes a realistic incident involving interpersonal conflict, principally criticism…

  4. Affective video retrieval: violence detection in Hollywood movies by large-scale segmental feature extraction.

    PubMed

    Eyben, Florian; Weninger, Felix; Lehment, Nicolas; Schuller, Björn; Rigoll, Gerhard

    2013-01-01

    Without doubt general video and sound, as found in large multimedia archives, carry emotional information. Thus, audio and video retrieval by certain emotional categories or dimensions could play a central role for tomorrow's intelligent systems, enabling search for movies with a particular mood, computer aided scene and sound design in order to elicit certain emotions in the audience, etc. Yet, the lion's share of research in affective computing is exclusively focusing on signals conveyed by humans, such as affective speech. Uniting the fields of multimedia retrieval and affective computing is believed to lend to a multiplicity of interesting retrieval applications, and at the same time to benefit affective computing research, by moving its methodology "out of the lab" to real-world, diverse data. In this contribution, we address the problem of finding "disturbing" scenes in movies, a scenario that is highly relevant for computer-aided parental guidance. We apply large-scale segmental feature extraction combined with audio-visual classification to the particular task of detecting violence. Our system performs fully data-driven analysis including automatic segmentation. We evaluate the system in terms of mean average precision (MAP) on the official data set of the MediaEval 2012 evaluation campaign's Affect Task, which consists of 18 original Hollywood movies, achieving up to .398 MAP on unseen test data in full realism. An in-depth analysis of the worth of individual features with respect to the target class and the system errors is carried out and reveals the importance of peak-related audio feature extraction and low-level histogram-based video analysis.

  5. Affective Video Retrieval: Violence Detection in Hollywood Movies by Large-Scale Segmental Feature Extraction

    PubMed Central

    Eyben, Florian; Weninger, Felix; Lehment, Nicolas; Schuller, Björn; Rigoll, Gerhard

    2013-01-01

    Without doubt general video and sound, as found in large multimedia archives, carry emotional information. Thus, audio and video retrieval by certain emotional categories or dimensions could play a central role for tomorrow's intelligent systems, enabling search for movies with a particular mood, computer aided scene and sound design in order to elicit certain emotions in the audience, etc. Yet, the lion's share of research in affective computing is exclusively focusing on signals conveyed by humans, such as affective speech. Uniting the fields of multimedia retrieval and affective computing is believed to lend to a multiplicity of interesting retrieval applications, and at the same time to benefit affective computing research, by moving its methodology “out of the lab” to real-world, diverse data. In this contribution, we address the problem of finding “disturbing” scenes in movies, a scenario that is highly relevant for computer-aided parental guidance. We apply large-scale segmental feature extraction combined with audio-visual classification to the particular task of detecting violence. Our system performs fully data-driven analysis including automatic segmentation. We evaluate the system in terms of mean average precision (MAP) on the official data set of the MediaEval 2012 evaluation campaign's Affect Task, which consists of 18 original Hollywood movies, achieving up to .398 MAP on unseen test data in full realism. An in-depth analysis of the worth of individual features with respect to the target class and the system errors is carried out and reveals the importance of peak-related audio feature extraction and low-level histogram-based video analysis. PMID:24391704

  6. Fine-scale urbanization affects Odonata species diversity in ponds of a megacity (Paris, France)

    NASA Astrophysics Data System (ADS)

    Jeanmougin, Martin; Leprieur, Fabien; Loïs, Grégoire; Clergeau, Philippe

    2014-08-01

    Current developments in urban ecology include very few studies focused on pond ecosystems, though ponds are recognized as biodiversity hotspots. Using Odonata as an indicator model, we explored changes in species composition in ponds localized along an urban gradient of a megacity (Paris, France). We then assessed the relative importance of local- and landscape-scale variables in shaping Odonata α-diversity patterns using a model-averaging approach. Analyses were performed for adult (A) and adult plus exuviae (AE) census data. At 26 ponds, we recorded 657 adults and 815 exuviae belonging to 17 Odonata species. The results showed that the Odonata species assemblage composition was not determined by pond localization along the urban gradient. Similarly, pond characteristics were found to be similar among urban, suburban and periurban ponds. The analyses of AE census data revealed that fine-scale urbanization (i.e., increased density of buildings surrounding ponds) negatively affects Odonata α-diversity. In contrast, pond localization along the urban gradient weakly explained the α-diversity patterns. Several local-scale variables, such as the coverage of submerged macrophytes, were found to be significant drivers of Odonata α-diversity. Together, these results show that the degree of urbanization around ponds must be considered instead of pond localization along the urban gradient when assessing the potential impacts of urbanization on Odonata species diversity. This work also indicates the importance of exuviae sampling in understanding the response of Odonata to urbanization.

  7. The response of gross nitrogen mineralization to labile carbon inputs

    NASA Astrophysics Data System (ADS)

    Bengtson, Per

    2014-05-01

    Input of labile carbon sources to forest soils commonly result in priming, i.e. an increase in the microbial decomposition of soil organic matter. Efforts aimed at quantifying the extent of priming have, to date, largely focused on soil organic matter decomposition manifested as soil respiration. Less is known about how gross nitrogen mineralization responds to input of labile carbon. It is often assumed that increased priming results in decreased soil carbon stocks. However, microbial mineralization of organic nitrogen into plant available forms is a major factor limiting primary production in forests. If increased decomposition of soil organic matter in response to labile carbon is accompanied by a concurrent increased nitrogen mineralization, this could result in elevated primary production and higher rates of plant derived organic matter input to soils. Therefore, in order to fully understand the effect of priming on net ecosystem exchange and soil carbon stocks, it is vital to consider if increased decomposition of soil organic matter caused by priming also results in increased nitrogen mineralization. Here I present the results from a series of experiments aimed at determining if, and to which extent, gross nitrogen mineralization is stimulated by input of labile carbon. The results suggest that it is by no means uncommon to find an increase in gross N mineralization rates in response to labile carbon inputs. The magnitude of the increase seems dependent on the nitrogen status of the soil, as well as the concentration and rate of labile carbon inputs. However, continuous input of labile carbon sources that also contains nitrogen, e.g. amino acids, seems to inhibit rather than increase the mineralization of organic nitrogen. These findings suggest that there is a potential for a positive feedback between priming and primary production that needs to be considered in order to fully understand the influence of priming on net ecosystem exchange and soil carbon

  8. High-resolution imaging of labile phosphorus and its relationship with iron redox state in lake sediments.

    PubMed

    Gao, Yulu; Liang, Tao; Tian, Shuhan; Wang, Lingqing; Holm, Peter E; Bruun Hansen, Hans Christian

    2016-12-01

    A thorough understanding of the labile status and dynamics of phosphorus (P) and iron (Fe) across the sediment-water interface (SWI) is essential for managing internal P release in eutrophic lakes. Fe-coupled inactivation of P in sediments is an important factor which affects internal P release in freshwater lakes. In this study, two in-situ high-resolution diffusive gradients in thin films (DGT) techniques, Zr-Oxide DGT and ZrO-Chelex DGT, were used to investigate the release characteristics of P from sediments in a large freshwater lake (Dongting Lake, China; area of 2691 km(2)) experiencing a regional summer algal bloom. Two-dimensional distributions of labile P in sediments were imaged with the Zr-Oxide DGT without destruction of the original structure of the sediment layer at four sites of the lake. The concentration of DGT-labile P in the sediments, ranging from 0.007 to 0.206 mg L(-1), was highly heterogeneous across the profiles. The values of apparent diffusion flux (Fd) and release flux (Fr) of P varied between -0.027-0.197 mg m(-2) d(-1) and 0.037-0.332 mg m(-2) d(-1), respectively. Labile P showed a high and positive correlation (p < 0.01) with labile Fe(II) in the profiles, providing high-resolution evidence for the key role of Fe-redox cycling in labile P variation in sediments.

  9. In situ high-resolution evaluation of labile arsenic and mercury in sediment of a large shallow lake.

    PubMed

    Wang, Chao; Yao, Yu; Wang, Peifang; Hou, Jun; Qian, Jin; Yuan, Ye; Fan, Xiulei

    2016-01-15

    The precise evaluation of arsenic (As) and mercury (Hg) bioavailability in sediment is crucial to controlling As and Hg contamination, but traditional ex situ measurements hamper comprehensive analysis of labile As and Hg in sediment. In this study, we characterized in situ labile As and Hg in sediment of Lake Hongze using the zirconium (Zr) oxide diffusive gradients in thin films (DGT) technique and 3-mercaptopropyl functionalized silica gel DGT, respectively. The concentrations of DGT-labile As and Hg in the sediment profiles were found to exhibit considerable variation, ranging from 0.15 to 4.15 μg L(-1) for As and from 0.04 to 1.35 μg L(-1) for Hg. As and Hg flux values, calculated based on the concentration gradients measured from the DGT profiles for both the overlying water and sediment close to the sediment-water interface, were used to determine the contamination status of As and Hg. Flux values of As and Hg were between -0.066 and 0.067 ng cm(-2)d(-1) and between -0.0187 and 0.0181 ng cm(-2)d(-1), respectively. The GNU's Not Unix R (GNU R) programming language was used to identify outliers of As and Hg at various depths at the sampling sites. The results indicate that the sites with the most outliers were all located in the regions that were seriously affected by contaminants from the Huai River. The DGT-labile As and Hg concentrations in the 0-30 mm layer were found to be significantly correlated with concentrations of labile As and Hg, total dissolved As and Hg, and total As and Hg in the overlying water, as indicated by ex situ measurements. Results show that DGT is a reliable and high-resolution technique that can be used for in situ monitoring of the labile fractions of As and Hg in sediment in fresh water bodies.

  10. Scaling up nutrition in fragile and conflict-affected states: the pivotal role of governance.

    PubMed

    Taylor, Sebastian A J; Perez-Ferrer, Carolina; Griffiths, Andrew; Brunner, Eric

    2015-02-01

    Acute and chronic undernutrition undermine conditions for health, stability and socioeconomic development across the developing world. Although fragile and conflict-affected states have some of the highest rates of undernutrition globally, their response to the multilateral 'Scaling Up Nutrition' (SUN) initiative in its first two-year period was ambivalent. The purpose of this research was to investigate factors affecting fragile and conflict-affected states' engagement with SUN, and to examine what differentiated those fragile states that joined SUN in its first phase from those that did not. Drawing on global databases (Unicef, World Bank, UNDP), and qualitative country case studies (Afghanistan, the Democratic Republic of Congo, Sierra Leone, Pakistan and Yemen) we used bivariate logistic regressions and principal component analysis to assess social, economic and political factors across 41 fragile states looking for systematic differences between those that had signed up to SUN before March 2013 (n = 16), and those that had not (n = 25). While prevalence of malnutrition, health system functioning and level of citizen empowerment had little or no impact on a fragile state's likelihood of joining SUN, the quality of governance (QOG) strongly predicted accession. SUN-signatory fragile states scored systematically better on the World Bank's Country Policy and Institutional Assessment (CPIA) and the Worldwide Governance Indicators 'effectiveness of government' indices. We conclude that strengthening governance in fragile states may enhance their engagement with initiatives such as SUN, but also (recognising the potential for endogeneity), that the way aid is structured and delivered in fragile states may be an underlying determinant of whether and how governance in such contexts improves. The research demonstrates that more nuanced analysis of conditions within and among countries classed as 'fragile and conflict-affected' is both possible and necessary if aid

  11. Examining affect and perfectionism in relation to eating disorder symptoms among women with anorexia nervosa.

    PubMed

    Lavender, Jason M; Mason, Tyler B; Utzinger, Linsey M; Wonderlich, Stephen A; Crosby, Ross D; Engel, Scott G; Mitchell, James E; Le Grange, Daniel; Crow, Scott J; Peterson, Carol B

    2016-07-30

    This study examined personality and affective variables in relation to eating disorder symptoms in anorexia nervosa (AN). Women (N=118) with DSM-IV AN completed baseline questionnaires (Beck Depression Inventory, Frost Multidimensional Perfectionism Scale) and interviews (Eating Disorder Examination, Yale-Brown-Cornell Eating Disorder Scale), followed by two weeks of ecological momentary assessment (EMA) involving multiple daily reports of affective states and eating disorder behaviors. Hierarchical regression analyses were conducted using eating disorder symptoms as dependent variables (i.e., EMA binge eating, EMA self-induced vomiting, eating disorder rituals, eating disorder preoccupations, dietary restraint). Predictor variables were maladaptive perfectionism (baseline), depressive symptoms (baseline), and affect lability (EMA). Results revealed that affect lability was independently associated with binge eating, whereas depressive symptoms were independently associated with self-induced vomiting. Depressive symptoms were independently associated with eating disorder rituals, whereas both depressive symptoms and maladaptive perfectionism were independently associated with eating disorder preoccupations. Finally, maladaptive perfectionism and affect lability were both independently associated with dietary restraint. This pattern of findings suggests the importance of affective and personality constructs in relation to eating disorder symptoms in AN and may highlight the importance of targeting these variables in the context of treatment.

  12. Phylogenetic congruence of lichenised fungi and algae is affected by spatial scale and taxonomic diversity

    PubMed Central

    Rafat, Arash; Ridden, Johnathon D.; Cruickshank, Robert H.; Ridgway, Hayley J.; Paterson, Adrian M.

    2014-01-01

    The role of species’ interactions in structuring biological communities remains unclear. Mutualistic symbioses, involving close positive interactions between two distinct organismal lineages, provide an excellent means to explore the roles of both evolutionary and ecological processes in determining how positive interactions affect community structure. In this study, we investigate patterns of co-diversification between fungi and algae for a range of New Zealand lichens at the community, genus, and species levels and explore explanations for possible patterns related to spatial scale and pattern, taxonomic diversity of the lichens considered, and the level sampling replication. We assembled six independent datasets to compare patterns in phylogenetic congruence with varied spatial extent of sampling, taxonomic diversity and level of specimen replication. For each dataset, we used the DNA sequences from the ITS regions of both the fungal and algal genomes from lichen specimens to produce genetic distance matrices. Phylogenetic congruence between fungi and algae was quantified using distance-based redundancy analysis and we used geographic distance matrices in Moran’s eigenvector mapping and variance partitioning to evaluate the effects of spatial variation on the quantification of phylogenetic congruence. Phylogenetic congruence was highly significant for all datasets and a large proportion of variance in both algal and fungal genetic distances was explained by partner genetic variation. Spatial variables, primarily at large and intermediate scales, were also important for explaining genetic diversity patterns in all datasets. Interestingly, spatial structuring was stronger for fungal than algal genetic variation. As the spatial extent of the samples increased, so too did the proportion of explained variation that was shared between the spatial variables and the partners’ genetic variation. Different lichen taxa showed some variation in their phylogenetic

  13. Phylogenetic congruence of lichenised fungi and algae is affected by spatial scale and taxonomic diversity.

    PubMed

    Buckley, Hannah L; Rafat, Arash; Ridden, Johnathon D; Cruickshank, Robert H; Ridgway, Hayley J; Paterson, Adrian M

    2014-01-01

    The role of species' interactions in structuring biological communities remains unclear. Mutualistic symbioses, involving close positive interactions between two distinct organismal lineages, provide an excellent means to explore the roles of both evolutionary and ecological processes in determining how positive interactions affect community structure. In this study, we investigate patterns of co-diversification between fungi and algae for a range of New Zealand lichens at the community, genus, and species levels and explore explanations for possible patterns related to spatial scale and pattern, taxonomic diversity of the lichens considered, and the level sampling replication. We assembled six independent datasets to compare patterns in phylogenetic congruence with varied spatial extent of sampling, taxonomic diversity and level of specimen replication. For each dataset, we used the DNA sequences from the ITS regions of both the fungal and algal genomes from lichen specimens to produce genetic distance matrices. Phylogenetic congruence between fungi and algae was quantified using distance-based redundancy analysis and we used geographic distance matrices in Moran's eigenvector mapping and variance partitioning to evaluate the effects of spatial variation on the quantification of phylogenetic congruence. Phylogenetic congruence was highly significant for all datasets and a large proportion of variance in both algal and fungal genetic distances was explained by partner genetic variation. Spatial variables, primarily at large and intermediate scales, were also important for explaining genetic diversity patterns in all datasets. Interestingly, spatial structuring was stronger for fungal than algal genetic variation. As the spatial extent of the samples increased, so too did the proportion of explained variation that was shared between the spatial variables and the partners' genetic variation. Different lichen taxa showed some variation in their phylogenetic congruence

  14. Simulating wind-affected snow accumulations at catchment to basin scales

    NASA Astrophysics Data System (ADS)

    Winstral, Adam; Marks, Danny; Gurney, Robert

    2013-05-01

    In non-forested mountain regions, wind plays a dominant role in determining snow accumulation and melt patterns. A new, computationally efficient algorithm for distributing the complex and heterogeneous effects of wind on snow distributions was developed. The distribution algorithm uses terrain structure, vegetation, and wind data to adjust commonly available precipitation data to simulate wind-affected accumulations. This research describes model development and application in three research catchments in the Reynolds Creek Experimental Watershed in southwest Idaho, USA. All three catchments feature highly variable snow distributions driven by wind. The algorithm was used to derive model forcings for Isnobal, a mass and energy balance distributed snow model. Development and initial testing took place in the Reynolds Mountain East catchment (0.36 km2) where R2 values for the wind-affected snow distributions ranged from 0.50 to 0.67 for four observation periods spanning two years. At the Upper Sheep Creek catchment (0.26 km2) R2 values for the wind-affected model were 0.66 and 0.70. These R2 values matched or exceeded previously published cross-validation results from regression-based statistical analyses of snow distributions in similar environments. In both catchments the wind-affected model accurately located large drift zones, snow-scoured slopes, and produced melt patterns consistent with observed streamflow. Models that did not account for wind effects produced relatively homogenous SWE distributions, R2 values approaching 0.0, and melt patterns inconsistent with observed streamflow. The Dobson Creek (14.0 km2) application incorporated elevation effects into the distribution routine and was conducted over a two-dimensional grid of 6.67 × 105 pixels. Comparisons with satellite-derived snow-covered-area again demonstrated that the model did an excellent job locating regions with wind-affected snow accumulations. This final application demonstrated that the

  15. Repeated Labilization-Reconsolidation Processes Strengthen Declarative Memory in Humans

    PubMed Central

    Forcato, Cecilia; Rodríguez, María L. C.; Pedreira, María E.

    2011-01-01

    The idea that memories are immutable after consolidation has been challenged. Several reports have shown that after the presentation of a specific reminder, reactivated old memories become labile and again susceptible to amnesic agents. Such vulnerability diminishes with the progress of time and implies a re-stabilization phase, usually referred to as reconsolidation. To date, the main findings describe the mechanisms associated with the labilization-reconsolidation process, but little is known about its functionality from a biological standpoint. Indeed, two functions have been proposed. One suggests that destabilization of the original memory after the reminder allows the integration of new information into the background of the original memory (memory updating), and the other suggests that the labilization-reconsolidation process strengthens the original memory (memory strengthening). We have previously reported the reconsolidation of human declarative memories, demonstrating memory updating in the framework of reconsolidation. Here we deal with the strengthening function attributed to the reconsolidation process. We triggered labilization-reconsolidation processes successively by repeated presentations of the proper reminder. Participants learned an association between five cue-syllables and their respective response-syllables. Twenty-four hours later, the paired-associate verbal memory was labilized by exposing the subjects to one, two or four reminders. The List-memory was evaluated on Day 3 showing that the memory was improved when at least a second reminder was presented in the time window of the first labilization-reconsolidation process prompted by the earlier reminder. However, the improvement effect was revealed on Day 3, only when at least two reminders were presented on Day2 and not as a consequence of only retrieval. Therefore, we propose central concepts for the reconsolidation process, emphasizing its biological role and the parametrical constrains

  16. Labile trace elements in carbonaceous chondrites - A survey

    NASA Technical Reports Server (NTRS)

    Xiao, Xiaoyue; Lipschutz, Michael E.

    1992-01-01

    Data are presented on 14 trace elements, including Co, Au, Ga, Rb, Sb, Ag, Se, Cs, Te, Zn, Cd, Bi, Tl, and In (nearly all of which are moderately or highly labile in meteorites), obtained by radiochemical neutron activation analyses of 42 C2-C6 chondrites, all but three from Antarctica. The data indicate that carbonaceous chondrites of petrographic types 2-6 define compositional continua. It is suggested that carbonaceous C2-C6 chondrites may reflect a mixture of material that formed at low temperatures and that contained cosmic levels of highly labile elements, with material that was devoid of them.

  17. Large-scale brain networks are distinctly affected in right and left mesial temporal lobe epilepsy.

    PubMed

    de Campos, Brunno Machado; Coan, Ana Carolina; Lin Yasuda, Clarissa; Casseb, Raphael Fernandes; Cendes, Fernando

    2016-09-01

    Mesial temporal lobe epilepsy (MTLE) with hippocampus sclerosis (HS) is associated with functional and structural alterations extending beyond the temporal regions and abnormal pattern of brain resting state networks (RSNs) connectivity. We hypothesized that the interaction of large-scale RSNs is differently affected in patients with right- and left-MTLE with HS compared to controls. We aimed to determine and characterize these alterations through the analysis of 12 RSNs, functionally parceled in 70 regions of interest (ROIs), from resting-state functional-MRIs of 99 subjects (52 controls, 26 right- and 21 left-MTLE patients with HS). Image preprocessing and statistical analysis were performed using UF(2) C-toolbox, which provided ROI-wise results for intranetwork and internetwork connectivity. Intranetwork abnormalities were observed in the dorsal default mode network (DMN) in both groups of patients and in the posterior salience network in right-MTLE. Both groups showed abnormal correlation between the dorsal-DMN and the posterior salience, as well as between the dorsal-DMN and the executive-control network. Patients with left-MTLE also showed reduced correlation between the dorsal-DMN and visuospatial network and increased correlation between bilateral thalamus and the posterior salience network. The ipsilateral hippocampus stood out as a central area of abnormalities. Alterations on left-MTLE expressed a low cluster coefficient, whereas the altered connections on right-MTLE showed low cluster coefficient in the DMN but high in the posterior salience regions. Both right- and left-MTLE patients with HS have widespread abnormal interactions of large-scale brain networks; however, all parameters evaluated indicate that left-MTLE has a more intricate bihemispheric dysfunction compared to right-MTLE. Hum Brain Mapp 37:3137-3152, 2016. © 2016 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

  18. How to Compute Labile Metal-Ligand Equilibria

    ERIC Educational Resources Information Center

    de Levie, Robert

    2007-01-01

    The different methods used for computing labile metal-ligand complexes, which are suitable for an iterative computer solution, are illustrated. The ligand function has allowed students to relegate otherwise tedious iterations to a computer, while retaining complete control over what is calculated.

  19. Neuropsychological Correlates of Emotional Lability in Children with ADHD

    ERIC Educational Resources Information Center

    Banaschewski, Tobias; Jennen-Steinmetz, Christine; Brandeis, Daniel; Buitelaar, Jan K.; Kuntsi, Jonna; Poustka, Luise; Sergeant, Joseph A.; Sonuga-Barke, Edmund J.; Frazier-Wood, Alexis C.; Albrecht, Bjorn; Chen, Wai; Uebel, Henrik; Schlotz, Wolff; van der Meere, Jaap J.; Gill, Michael; Manor, Iris; Miranda, Ana; Mulas, Fernando; Oades, Robert D.; Roeyers, Herbert; Rothenberger, Aribert; Steinhausen, Hans-Christoph; Faraone, Stephen V.; Asherson, Philip

    2012-01-01

    Background: Emotional lability (EL) is commonly seen in patients with attention-deficit/hyperactivity disorder (ADHD). The reasons for this association remain currently unknown. To address this question, we examined the relationship between ADHD and EL symptoms, and performance on a range of neuropsychological tasks to clarify whether EL symptoms…

  20. Psychometric Characteristics of the EEAA (Scale of Affective Strategies in the Learning Process)

    ERIC Educational Resources Information Center

    Villardón-Gallego, Lourdes; Yániz, Concepción

    2014-01-01

    Introduction: Affective strategies for coping with affective states linked to the learning process may be oriented toward controlling emotions or toward controlling motivation. Both types affect performance, directly and indirectly. The objective of this research was to design an instrument for measuring the affective strategies used by university…

  1. Non-labile silver species in biosolids remain stable throughout ...

    EPA Pesticide Factsheets

    Increasing commercial use of nanosilver has focussed attention on the fate of silver (Ag) in the wastewater release pathway. This paper reports the speciation and lability of Ag in archived, stockpiled, and contemporary biosolids from the UK, USA and Australia, and indicates that biosolids Ag concentrations have decreased significantly over recent decades. XANES revealed the importance of reduced-sulfur binding environments for Ag speciation in materials ranging from freshly produced sludge to biosolids weathered under ambient environmental conditions for more than 50 years. Isotopic dilution with 110mAg showed that Ag was predominantly non-labile in both fresh and aged biosolids (13.7% mean lability), with E-values ranging from 0.3 to 60 mg/kg and 5 mM CaNO3 extractable Ag from 1.2 to 609 µg/kg (0.002 - 3.4% of the total Ag). This study indicates that at the time of soil application, biosolids Ag will be predominantly Ag-sulfides and characterised by low isotopic lability. This paper presents an overview of biosolids Ag chemistry in historic and contemporary biosolids sourced from the UK, USA and Australia from the 1950s until today by drawing on a unique collection of archived, stockpiled and contemporary biosolids samples. Characteristics of biosolids Ag chemistry determined in this study included total Ag measurement by neutron activation analysis (NAA); the assessment of Ag lability by 110mAg isotopic dilution (E-values); and Ag speciation by X-ray Absorp

  2. Altered precipitation regime affects the function and composition of soil microbial communities on multiple time scales.

    PubMed

    Zeglin, L H; Bottomley, P J; Jumpponen, A; Rice, C W; Arango, M; Lindsley, A; McGowan, A; Mfombep, P; Myrold, D D

    2013-10-01

    Climate change models predict that future precipitation patterns will entail lower-frequency but larger rainfall events, increasing the duration of dry soil conditions. Resulting shifts in microbial C cycling activity could affect soil C storage. Further, microbial response to rainfall events may be constrained by the physiological or nutrient limitation stress of extended drought periods; thus seasonal or multiannual precipitation regimes may influence microbial activity following soil wet-up. We quantified rainfall-driven dynamics of microbial processes that affect soil C loss and retention, and microbial community composition, in soils from a long-term (14-year) field experiment contrasting "Ambient" and "Altered" (extended intervals between rainfalls) precipitation regimes. We collected soil before, the day following, and five days following 2.5-cm rainfall events during both moist and dry periods (June and September 2011; soil water potential = -0.01 and -0.83 MPa, respectively), and measured microbial respiration, microbial biomass, organic matter decomposition potential (extracellular enzyme activities), and microbial community composition (phospholipid fatty acids). The equivalent rainfall events caused equivalent microbial respiration responses in both treatments. In contrast, microbial biomass was higher and increased after rainfall in the Altered treatment soils only, thus microbial C use efficiency (CUE) was higher in Altered than Ambient treatments (0.70 +/- 0.03 > 0.46 +/- 0.10). CUE was also higher in dry (September) soils. C-acquiring enzyme activities (beta-glucosidase, cellobiohydrolase, and phenol oxidase) increased after rainfall in moist (June), but not dry (September) soils. Both microbial biomass C:N ratios and fungal:bacterial ratios were higher at lower soil water contents, suggesting a functional and/or population-level shift in the microbiota at low soil water contents, and microbial community composition also differed following wet

  3. Quantification of Labile Soil Mercury by Stable Isotope Dilution Techniques

    NASA Astrophysics Data System (ADS)

    Shetaya, Waleed; Huang, Jen-How; Osterwalder, Stefan; Alewell, Christine

    2016-04-01

    Mercury (Hg) is a toxic element that can cause severe health problems to humans. Mercury is emitted to the atmosphere from both natural and anthropogenic sources and can be transported over long distances before it is deposited to aquatic and terrestrial environments. Aside from accumulation in soil solid phases, Hg deposited in soils may migrate to surface- and ground-water or enter the food chain, depending on its lability. There are many operationally-defined extraction methods proposed to quantify soil labile metals. However, these methods are by definition prone to inaccuracies such as non-selectivity, underestimation or overestimation of the labile metal pool. The isotopic dilution technique (ID) is currently the most promising method for discrimination between labile and non-labile metal fractions in soil with a minimum disturbance to soil-solid phases. ID assesses the reactive metal pool in soil by defining the fraction of metal both in solid and solution phases that is isotopically-exchangeable known as the 'E-value'. The 'E-value' represents the metal fraction in a dynamic equilibrium with the solution phase and is potentially accessible to plants. This is carried out by addition of an enriched metal isotope to soil suspensions and quantifying the fraction of metal that is able to freely exchange with the added isotope by measuring the equilibrium isotopic ratio by ICP-MS. E-value (mg kg-1) is then calculated as follows: E-Value = (Msoil/ W) (CspikeVspike/ Mspike) (Iso1IAspike -Iso2IAspikeRss / Iso2IAsoil Rss - Iso1IAsoil) where M is the average atomic mass of the metal in the soil or the spike, W is the mass of soil (kg), Cspike is the concentration of the metal in the spike (mg L-1), Vspike is the volume of spike (L), IA is isotopic abundance, and Rss is the equilibrium ratio of isotopic abundances (Iso1:Iso2). Isotopic dilution has been successfully applied to determine E-values for several elements. However, to our knowledge, this method has not yet

  4. The Post-Deployment Reintegration Scale: Associations with Organizational Commitment, Job-Related Affect, and Career Intentions

    DTIC Science & Technology

    2006-11-01

    The post-deployment reintegration scale: Associations with organizational commitment, job-related affect, and career intentions Ann-Renée Blais...Recherche et développement pour la défense Canada DEFENCE DÉFENSE & The post-deployment reintegration scale: Associations with organizational... reintegration can lead to intra- and/or inter-personal changes that may influence the quality of their relationships with family, friends, and

  5. Data on schizotypy and affective scales are gender and education dependent--study in the Northern Finland 1966 Birth Cohort.

    PubMed

    Miettunen, Jouko; Veijola, Juha; Freimer, Nelson; Lichtermann, Dirk; Peltonen, Leena; Paunio, Tiina; Isohanni, Matti; Joukamaa, Matti; Ekelund, Jesper

    2010-07-30

    We present psychometric properties and normative data by gender and educational level in scales related to schizotypy and affective disorders in a large population-based adult sample. As part of the 31-year follow-up survey of the Northern Finland 1966 Birth Cohort; Bipolar II scale (BIP2), Hypomanic Personality Scale (HPS), Physical Anhedonia Scale (PAS), Social Anhedonia Scale (SAS), Perceptual Aberration Scale (PER) and Schizoidia Scale (SCHD) were filled in by 4928 subjects. In total sample mean scores were: BIP2 10.59 (3.80), HPS 11.26 (7.03), PAS 14.99 (S.D. 7.03), SAS 9.44 (5.52), PER 2.35 (3.26) and SCHD 2.56 (1.42). Men scored higher (had more psychopathological symptoms) in PAS and SAS (P<0.001), and in BIP2 (P=0.02). Women had higher scores in SCHD, HPS and PER (P<0.001). Participants with a lower level of education scored higher in all scales; differences were largest in BIP2, PAS and SAS (ES>0.5,P<0.001). The gender and education differences were moderate or large in all the included scales. These differences should be taken into account when considering normal values in these scales. The findings indicate that commonly used student samples are likely to be biased when compared to community based samples.

  6. Detection of macro-ecological patterns in South American hummingbirds is affected by spatial scale.

    PubMed Central

    Rahbek, C; Graves, G R

    2000-01-01

    Scale is widely recognized as a fundamental conceptual problem in biology, but the question of whether species-richness patterns vary with scale is often ignored in macro-ecological analyses, despite the increasing application of such data in international conservation programmes. We tested for scaling effects in species-richness gradients with spatially scaled data for 241 species of South American hummingbirds (Trochilidae). Analyses revealed that scale matters above and beyond the effect of quadrat area. Species richness was positively correlated with latitude and topographical relief at ten different spatial scales spanning two orders of magnitude (ca. 12,300 to ca. 1,225,000 km2). Surprisingly, when the influence of topography was removed, the conditional variation in species richness explained by latitude fell precipitously to insignificance at coarser spatial scales. The perception of macro-ecological pattern thus depends directly upon the scale of analysis. Although our results suggest there is no single correct scale for macro-ecological analyses, the averaging effect of quadrat sampling at coarser geographical scales obscures the fine structure of species-richness gradients and localized richness peaks, decreasing the power of statistical tests to discriminate the causal agents of regional richness gradients. Ideally, the scale of analysis should be varied systematically to provide the optimal resolution of macro-ecological pattern. PMID:11413641

  7. Psychometric Properties of the Positive and Negative Affect Scale for Children (PANAS-C) in Children with Anxiety Disorders

    ERIC Educational Resources Information Center

    Hughes, Alicia A.; Kendall, Philip C.

    2009-01-01

    This study investigated the psychometric properties of the Positive and Negative Affect Scale for Children (PANAS-C) (Laurent et al. Psychol Asses 1: 326-338, 1999) in a sample of 139 children (ages 7-14 years) diagnosed with a principal anxiety disorder. Results from this study provided support for the convergent validity of the PANAS-C with…

  8. The Consequences of Perfectionism Scale: Factorial Structure and Relationships with Perfectionism, Performance Perfectionism, Affect, and Depressive Symptoms

    ERIC Educational Resources Information Center

    Stoeber, Joachim; Hoyle, Azina; Last, Freyja

    2013-01-01

    This study investigated the Consequences of Perfectionism Scale (COPS) and its relationships with perfectionism, performance perfectionism, affect, and depressive symptoms in 202 university students using confirmatory factor analysis, correlations, and regression analyses. Results suggest that the COPS is a reliable and valid measure of positive…

  9. The role of affective instability and UPPS impulsivity in borderline personality disorder features.

    PubMed

    Tragesser, Sarah L; Robinson, R Joe

    2009-08-01

    Current theories of borderline personality disorder (BPD) suggest that extreme levels of affective instability/emotional dysregulation, impulsivity, or a combination of these traits account for the symptoms of BPD. The present study tested the extent to which personality measures of affective instability and impulsivity could account for BPD features in a nonclinical sample. One hundred forty-one undergraduates completed the Affective Lability Scale, the UPPS Impulsive Behavior Scale, and the Personality Assessment Inventory for Borderlines. Both affective instability and impulsivity were uniquely associated with BPD features. Shifts between euthymia and anger, and between anxiety and depression, were associated with BPD features, as were the urgency and (lack of) premeditation scales. Results indicated that specific BPD features may be differentially accounted for by affective instability vs. impulsivity, consistent with perspectives on BPD emphasizing combinations of affective instability and impulsivity as underlying dimensions of the disorder.

  10. Multi-Scale Modeling of Liquid Phase Sintering Affected by Gravity: Preliminary Analysis

    NASA Technical Reports Server (NTRS)

    Olevsky, Eugene; German, Randall M.

    2012-01-01

    A multi-scale simulation concept taking into account impact of gravity on liquid phase sintering is described. The gravity influence can be included at both the micro- and macro-scales. At the micro-scale, the diffusion mass-transport is directionally modified in the framework of kinetic Monte-Carlo simulations to include the impact of gravity. The micro-scale simulations can provide the values of the constitutive parameters for macroscopic sintering simulations. At the macro-scale, we are attempting to embed a continuum model of sintering into a finite-element framework that includes the gravity forces and substrate friction. If successful, the finite elements analysis will enable predictions relevant to space-based processing, including size and shape and property predictions. Model experiments are underway to support the models via extraction of viscosity moduli versus composition, particle size, heating rate, temperature and time.

  11. Changes in labile soil organic matter fractions following land use change from monocropping to poplar-based agroforestry systems in a semiarid region of Northeast China.

    PubMed

    Mao, Rong; Zeng, De-Hui; Li, Lu-Jun; Hu, Ya-Lin

    2012-11-01

    Labile fractions of soil organic matter (SOM) respond rapidly to land management practices and can be used as a sensitive indicator of changes in SOM. However, there is little information about the effect of agroforestry practices on labile SOM fractions in semiarid regions of China. In order to test the effects of land use change from monocropping to agroforestry systems on labile SOM fractions, we investigated soil microbial biomass C (MBC) and N, particulate organic matter C (POMC) and N (POMN), as well as total organic C (TOC) and total N (TN) in the 0- to 15-cm and the 15- to 30-cm layers in 4-year-old poplar-based agroforestry systems and adjoining monocropping systems with two different soil textures (sandy loam and sandy clay loam) in a semiarid region of Northeast China. Our results showed that poplar-based agroforestry practices affected soil MBC, POMC, and POMN, albeit there was no significant difference in TOC and TN. Agroforestry practices increased MBC, POMC, and POMN in sandy clay loam soils. However, in sandy loam soils, agroforestry practices only increased MBC and even decreased POMC and POMN at the 0- to 15-cm layer. Our results suggest that labile SOM fractions respond sensitively to poplar-based agroforestry practices and can provide early information about the changes in SOM in semiarid regions of Northeast China and highlight that the effects of agroforestry practices on labile SOM fractions vary with soil texture.

  12. Field experimental approach to bromide leaching as affected by scale-specific rainfall characteristics

    NASA Astrophysics Data System (ADS)

    Wendroth, Ole; Vasquez, Vicente; Matocha, Christopher J.

    2011-06-01

    Although inherent soil spatial and temporal variabilities complicate analysis of solute leaching, impacts of specific processes associated with rainfall amount, intensity, and frequency on solute leaching under field conditions require investigation. The objective of this study was to introduce (1) a new experimental approach to quantify bromide (Br-) leaching under field conditions as influenced by rainfall characteristics and (2) analytical opportunities applicable to scale-specific spatial treatment distribution. The quantitative range of treatments was established in nonrandom periodically oscillating patterns. The characteristic length of a period over which a treatment fluctuates was considered the specific treatment scale. A Br- tracer study was established in the field with treatments applied at two different spatial scales. The tracer was applied with a sprayer in a transect of 32 plots, each 2 m long, followed by a site-specific sprinkler irrigation, and 128 soil cores subsequently taken at 0.5 m intervals and divided into 10-cm depth increments. The scale-specific associations between treatments and Br- center of mass (COM) were addressed. Treatments can be periodically imposed over specific scales and their spatial relationships quantified with semivariance and power spectral analysis. An additive state-space model was applied to separate the long- and short-wave components of Br- COM. Subsequently, the large-scale process was described in an autoregressive state-space model. The proposed experimental approach and the separation of small- and large-scale variability components support studying soil ecosystem processes that vary at different scales even in the presence of underlying large-scale trends that are currently considered obstacles in field research.

  13. Monitoring and assessment of soil erosion at micro-scale and macro-scale in forests affected by fire damage in northern Iran.

    PubMed

    Akbarzadeh, Ali; Ghorbani-Dashtaki, Shoja; Naderi-Khorasgani, Mehdi; Kerry, Ruth; Taghizadeh-Mehrjardi, Ruhollah

    2016-12-01

    Understanding the occurrence of erosion processes at large scales is very difficult without studying them at small scales. In this study, soil erosion parameters were investigated at micro-scale and macro-scale in forests in northern Iran. Surface erosion and some vegetation attributes were measured at the watershed scale in 30 parcels of land which were separated into 15 fire-affected (burned) forests and 15 original (unburned) forests adjacent to the burned sites. The soil erodibility factor and splash erosion were also determined at the micro-plot scale within each burned and unburned site. Furthermore, soil sampling and infiltration studies were carried out at 80 other sites, as well as the 30 burned and unburned sites, (a total of 110 points) to create a map of the soil erodibility factor at the regional scale. Maps of topography, rainfall, and cover-management were also determined for the study area. The maps of erosion risk and erosion risk potential were finally prepared for the study area using the Revised Universal Soil Loss Equation (RUSLE) procedure. Results indicated that destruction of the protective cover of forested areas by fire had significant effects on splash erosion and the soil erodibility factor at the micro-plot scale and also on surface erosion, erosion risk, and erosion risk potential at the watershed scale. Moreover, the results showed that correlation coefficients between different variables at the micro-plot and watershed scales were positive and significant. Finally, assessment and monitoring of the erosion maps at the regional scale showed that the central and western parts of the study area were more susceptible to erosion compared with the western regions due to more intense crop-management, greater soil erodibility, and more rainfall. The relationships between erosion parameters and the most important vegetation attributes were also used to provide models with equations that were specific to the study region. The results of this

  14. Two clusters of GABAergic ellipsoid body neurons modulate olfactory labile memory in Drosophila.

    PubMed

    Zhang, Zhiping; Li, Xiaoting; Guo, Jing; Li, Yan; Guo, Aike

    2013-03-20

    In Drosophila, aversive olfactory memory is believed to be stored in a prominent brain structure, the mushroom body (MB), and two pairs of MB intrinsic neurons, the dorsal paired medial (DPM) and the anterior paired lateral (APL) neurons, are found to regulate the consolidation of middle-term memory (MTM). Here we report that another prominent brain structure, the ellipsoid body (EB), is also involved in the modulation of olfactory MTM. Activating EB R2/R4m neurons does not affect the learning index, but specifically eliminates anesthesia-sensitive memory (ASM), the labile component of olfactory MTM. We further demonstrate that approximately two-thirds of these EB neurons are GABAergic and are responsible for the suppression of ASM. Using GRASP (GFP reconstitution across synaptic partners), we reveal potential synaptic connections between the EB and MB in regions covering both the presynaptic and postsynaptic sites of EB neurons, suggesting the presence of bidirectional connections between these two important brain structures. These findings suggest the existence of direct connections between the MB and EB, and provide new insights into the neural circuit basis for olfactory labile memory in Drosophila.

  15. Activity affects intraspecific body-size scaling of metabolic rate in ectothermic animals.

    PubMed

    Glazier, Douglas Stewart

    2009-10-01

    Metabolic rate is commonly thought to scale with body mass (M) to the 3/4 power. However, the metabolic scaling exponent (b) may vary with activity state, as has been shown chiefly for interspecific relationships. Here I use a meta-analysis of literature data to test whether b changes with activity level within species of ectothermic animals. Data for 19 species show that b is usually higher during active exercise (mean +/- 95% confidence limits = 0.918 +/- 0.038) than during rest (0.768 +/- 0.069). This significant upward shift in b to near 1 is consistent with the metabolic level boundaries hypothesis, which predicts that maximal metabolic rate during exercise should be chiefly influenced by volume-related muscular power production (scaling as M (1)). This dependence of b on activity level does not appear to be a simple temperature effect because body temperature in ectotherms changes very little during exercise.

  16. Length scale of the dendritic microstructure affecting tensile properties of Al-(Ag)-(Cu) alloys

    NASA Astrophysics Data System (ADS)

    Duarte, Roberto N.; Faria, Jonas D.; Brito, Crystopher; Veríssimo, Nathalia C.; Cheung, Noé; Garcia, Amauri

    2016-12-01

    The dependence of tensile properties on the length scale of the dendritic morphology of Al-Cu, Al-Ag and Al-Ag-Cu alloys is experimentally investigated. These alloys were directionally solidified (DS) under a wide range of cooling rates (Ṫ), permitting extensive microstructural scales to be examined. Experimental growth laws are proposed relating the primary dendritic arm spacing, λ1 to Ṫ and tensile properties to λ1. It is shown that the most significant effect of the scale of λ1 on the tensile properties is that of the ternary alloy, which is attributed to the more homogeneous distribution of the eutectic mixture for smaller λ1 and by the combined reinforcement roles of the intermetallics present in the ternary eutectic: Al2Cu and nonequilibrium Ag3Al.

  17. FIELD-SCALE STUDIES: HOW DOES SOIL SAMPLE PRETREATMENT AFFECT REPRESENTATIVENESS?

    EPA Science Inventory

    Samples from field-scale studies are very heterogeneous and can contain large soil and rock particles. Oversize materials are often removed before chemical analysis of the soil samples because it is not practical to include these materials. Is the extracted sample representativ...

  18. FIELD-SCALE STUDIES: HOW DOES SOIL SAMPLE PRETREATMENT AFFECT REPRESENTATIVENESS ? (ABSTRACT)

    EPA Science Inventory

    Samples from field-scale studies are very heterogeneous and can contain large soil and rock particles. Oversize materials are often removed before chemical analysis of the soil samples because it is not practical to include these materials. Is the extracted sample representativ...

  19. Parameters affecting the resilience of scale-free networks to random failures.

    SciTech Connect

    Link, Hamilton E.; LaViolette, Randall A.; Lane, Terran; Saia, Jared

    2005-09-01

    It is commonly believed that scale-free networks are robust to massive numbers of random node deletions. For example, Cohen et al. in (1) study scale-free networks including some which approximate the measured degree distribution of the Internet. Their results suggest that if each node in this network failed independently with probability 0.99, most of the remaining nodes would still be connected in a giant component. In this paper, we show that a large and important subclass of scale-free networks are not robust to massive numbers of random node deletions. In particular, we study scale-free networks which have minimum node degree of 1 and a power-law degree distribution beginning with nodes of degree 1 (power-law networks). We show that, in a power-law network approximating the Internet's reported distribution, when the probability of deletion of each node is 0.5 only about 25% of the surviving nodes in the network remain connected in a giant component, and the giant component does not persist beyond a critical failure rate of 0.9. The new result is partially due to improved analytical accommodation of the large number of degree-0 nodes that result after node deletions. Our results apply to power-law networks with a wide range of power-law exponents, including Internet-like networks. We give both analytical and empirical evidence that such networks are not generally robust to massive random node deletions.

  20. Non-native salmonids affect amphibian occupancy at multiple spatial scales

    USGS Publications Warehouse

    Pilliod, David S.; Hossack, Blake R.; Bahls, Peter F.; Bull, Evelyn L.; Corn, Paul Stephen; Hokit, Grant; Maxell, Bryce A.; Munger, James C.; Wyrick, Aimee

    2010-01-01

    Aim The introduction of non-native species into aquatic environments has been linked with local extinctions and altered distributions of native species. We investigated the effect of non-native salmonids on the occupancy of two native amphibians, the long-toed salamander (Ambystoma macrodactylum) and Columbia spotted frog (Rana luteiventris), across three spatial scales: water bodies, small catchments and large catchments. Location Mountain lakes at ≥ 1500 m elevation were surveyed across the northern Rocky Mountains, USA. Methods We surveyed 2267 water bodies for amphibian occupancy (based on evidence of reproduction) and fish presence between 1986 and 2002 and modelled the probability of amphibian occupancy at each spatial scale in relation to habitat availability and quality and fish presence. Results After accounting for habitat features, we estimated that A. macrodactylum was 2.3 times more likely to breed in fishless water bodies than in water bodies with fish. Ambystoma macrodactylum also was more likely to occupy small catchments where none of the water bodies contained fish than in catchments where at least one water body contained fish. However, the probability of salamander occupancy in small catchments was also influenced by habitat availability (i.e. the number of water bodies within a catchment) and suitability of remaining fishless water bodies. We found no relationship between fish presence and salamander occupancy at the large-catchment scale, probably because of increased habitat availability. In contrast to A. macrodactylum, we found no relationship between fish presence and R. luteiventris occupancy at any scale. Main conclusions Our results suggest that the negative effects of non-native salmonids can extend beyond the boundaries of individual water bodies and increase A. macrodactylum extinction risk at landscape scales. We suspect that niche overlap between non-native fish and A. macrodactylum at higher elevations in the northern Rocky

  1. Hourly Fluctuations in Labile Soil Phosphorus in Response to Climate Variability in a Wet Tropical Forest, La Selva, Costa Rica

    NASA Astrophysics Data System (ADS)

    Vandecar, K. L.; Lawrence, D. C.; Das, R.; Clark, D. A.; Oberbauer, S. F.; Schwendenmann, L.

    2007-05-01

    Tropical rain forests are one of the most productive ecosystems in the world and play a significant role in the global carbon budget. Changes in phosphorus cycling dynamics as a result of on-going climate change have the potential to limit productivity in this ecosystem. Our objective was to determine hourly patterns in labile soil phosphorus throughout the day and explore possible mechanisms driving these patterns. We conducted an in situ experiment on soils from a wet tropical forest at La Selva Biological Station located in N.E. Costa Rica. A variety of climatic and biotic variables including temperature, precipitation, PAR, soil temperature, soil moisture and soil respiration were measured in order to determine their effect on labile phosphorus. Our results indicate that labile phosphorus does vary significantly throughout the day in response to a combination of climatic variables. An understanding of the mechanisms driving phosphorus availability at fine temporal scales can provide a valuable indicator of long term trends in phosphorus cycling dynamics.

  2. The Affective Reactivity Index: A Concise Irritability Scale for Clinical and Research Settings

    ERIC Educational Resources Information Center

    Stringaris, Argyris; Goodman, Robert; Ferdinando, Sumudu; Razdan, Varun; Muhrer, Eli; Leibenluft, Ellen; Brotman, Melissa A.

    2012-01-01

    Background: Irritable mood has recently become a matter of intense scientific interest. Here, we present data from two samples, one from the United States and the other from the United Kingdom, demonstrating the clinical and research utility of the parent- and self-report forms of the Affective Reactivity Index (ARI), a concise dimensional measure…

  3. Factors affecting the rate of hydrolysis of phenylboronic acid in lab-scale precipitate reactor studies

    SciTech Connect

    Bannochie, C.J.; Marek, J.C.; Eibling, R.E.; Baich, M.A.

    1992-01-01

    Removing aromatic carbon from an aqueous slurry of cesium-137 and other alkali tetraphenylborates by acid hydrolysis will be an important step in preparing high-level radioactive waste for vitrification at the Savannah River Site's Defense Waste Processing Facility (DWPF). Kinetic data obtained in bench-scale precipitate hydrolysis reactors suggest changes in operating parameters to improve product quality in the future plant-scale radioactive operation. The rate-determining step is the removal of the fourth phenyl group, i.e. hydrolysis of phenylboronic acid. Efforts to maximize this rate have established the importance of several factors in the system, including the ratio of copper(II) catalyst to formic acid, the presence of nitrite ion, reactions of diphenylmercury, and the purge gas employed in the system.

  4. Factors affecting the rate of hydrolysis of phenylboronic acid in lab-scale precipitate reactor studies

    SciTech Connect

    Bannochie, C.J.; Marek, J.C.; Eibling, R.E.; Baich, M.A.

    1992-10-01

    Removing aromatic carbon from an aqueous slurry of cesium-137 and other alkali tetraphenylborates by acid hydrolysis will be an important step in preparing high-level radioactive waste for vitrification at the Savannah River Site`s Defense Waste Processing Facility (DWPF). Kinetic data obtained in bench-scale precipitate hydrolysis reactors suggest changes in operating parameters to improve product quality in the future plant-scale radioactive operation. The rate-determining step is the removal of the fourth phenyl group, i.e. hydrolysis of phenylboronic acid. Efforts to maximize this rate have established the importance of several factors in the system, including the ratio of copper(II) catalyst to formic acid, the presence of nitrite ion, reactions of diphenylmercury, and the purge gas employed in the system.

  5. Developmental change and intraindividual variability: relating cognitive aging to cognitive plasticity, cardiovascular lability, and emotional diversity.

    PubMed

    Ram, Nilam; Gerstorf, Denis; Lindenberger, Ulman; Smith, Jacqui

    2011-06-01

    Repeated assessments obtained over years can be used to measure individuals' developmental change, whereas repeated assessments obtained over a few weeks can be used to measure individuals' dynamic characteristics. Using data from a burst of measurement embedded in the Berlin Aging Study (BASE; Baltes & Mayer, 1999), we illustrate and examine how long-term changes in cognitive ability are related to short-term changes in cognitive performance, cardiovascular function, and emotional experience. Our findings suggest that "better" cognitive aging over approximately 13 years was associated with greater cognitive plasticity, less cardiovascular lability, and less emotional diversity over approximately 2 weeks at age 90 years. The study highlights the potential benefits of multi-time scale longitudinal designs for the study of individual function and development.

  6. Scale-dependent diversity patterns affect spider assemblages of two contrasting forest ecosystems

    NASA Astrophysics Data System (ADS)

    Schuldt, Andreas; Assmann, Thorsten; Schaefer, Matthias

    2013-05-01

    Spiders are important generalist predators in forests. However, differences in assemblage structure and diversity can have consequences for their functional impact. Such differences are particularly evident across latitudes, and their analysis can help to generate a better understanding of region-specific characteristics of predator assemblages. Here, we analyse the relationships between species richness, family richness and functional diversity (FD) as well as α- and β-components of epigeic spider diversity in semi-natural temperate and subtropical forest sites. As expected, within-plot and overall spider species and family richness were higher in the subtropical plots. In contrast, local FD within plots was similar between sites, and differences in FD only became evident at larger spatial scales due to higher species turnover in the subtropical forests. Our study indicates that the functional effects of predator assemblages can change across spatial scales. We discuss how differences in richness and functional diversity between contrasting forest ecosystems can depend on environmental heterogeneity and the effects of species filters acting at local scales. The high turnover observed in the species-rich subtropical forests also requires a more regional perspective for the conservation of the overall diversity and the ecological functions of predators than in less diverse forests, as strategies need to account for the large spatial heterogeneity among plots.

  7. Dynamic spatial patterns of leaf traits affect total respiration on the crown scale

    NASA Astrophysics Data System (ADS)

    Wang, Xiaolin; Zhou, Hongxuan; Han, Fengsen; Li, Yuanzheng; Hu, Dan

    2016-05-01

    Temporal and spatial variations of leaf traits caused conflicting conclusions and great estimating errors of total carbon budget on crown scales. However, there is no effective method to quantitatively describe and study heterogeneous patterns of crowns yet. In this study, dynamic spatial patterns of typical ecological factors on crown scales were investigated during two sky conditions, and CEZs (crown ecological zones) method was developed for spatial crown zoning, within which leaf traits were statistically unchanged. The influencing factors on hourly and spatial variations of leaf dark respiration (Rd) were analysed, and total crown respiration (Rt) was estimated based on patterns of CEZs. The results showed that dynamic spatial patterns of air temperature and light intensity changed significantly by CEZs in special periods and positions, but not continuously. The contributions of influencing factors on variations of Rd changed with crown depth and sky conditions, and total contributions of leaf structural and chemical traits were higher during sunny days than ecological factors, but lower during cloudy days. The estimated errors of Rt may be obviously reduced with CEZs. These results provided some references for scaling from leaves to crown, and technical foundations for expanding lab-control experiments to open field ones.

  8. Dynamic spatial patterns of leaf traits affect total respiration on the crown scale

    PubMed Central

    Wang, Xiaolin; Zhou, Hongxuan; Han, Fengsen; Li, Yuanzheng; Hu, Dan

    2016-01-01

    Temporal and spatial variations of leaf traits caused conflicting conclusions and great estimating errors of total carbon budget on crown scales. However, there is no effective method to quantitatively describe and study heterogeneous patterns of crowns yet. In this study, dynamic spatial patterns of typical ecological factors on crown scales were investigated during two sky conditions, and CEZs (crown ecological zones) method was developed for spatial crown zoning, within which leaf traits were statistically unchanged. The influencing factors on hourly and spatial variations of leaf dark respiration (Rd) were analysed, and total crown respiration (Rt) was estimated based on patterns of CEZs. The results showed that dynamic spatial patterns of air temperature and light intensity changed significantly by CEZs in special periods and positions, but not continuously. The contributions of influencing factors on variations of Rd changed with crown depth and sky conditions, and total contributions of leaf structural and chemical traits were higher during sunny days than ecological factors, but lower during cloudy days. The estimated errors of Rt may be obviously reduced with CEZs. These results provided some references for scaling from leaves to crown, and technical foundations for expanding lab-control experiments to open field ones. PMID:27225586

  9. Agricultural land management options following large-scale environmental contamination - evaluation for Fukushima affected agricultural land

    SciTech Connect

    Vandenhove, Hildegarde

    2013-07-01

    The accident at the Fukushima Daiichi Nuclear Power Plant has raised questions about the accumulation of radionuclides in soils, the transfer in the food chain and the possibility of continued restricted future land use. This paper summarizes what is generally understood about the application of agricultural countermeasures as a land management option to reduce the radionuclides transfer in the food chain and to facilitate the return of potentially affected soils to agricultural practices in areas impacted by a nuclear accident. (authors)

  10. Spinal cord injury: reversing the incorrect cortical maps by inductive lability procedure.

    PubMed

    Krishnan, R V

    2004-06-01

    Within the brain-stem and on the cerebral cortex there are locomotor control centers arranged in a ladder-form control system. These centers are somatotopic, self-organizing neural network maps capable of simultaneously learning and task execution. In spinal cord injury (SCI) these self-organized maps get erroneously re-organized and maladaptively stabilized. The extent and quality of sensory-motor recovery, if any appears, is affected by and compromised due to incorrect mapping processes. The treatment method based on inductive lability procedure (Krishnan, 2003a, 2003b, 2003c) uses botulinum toxin for the purpose. It recreates competition among synapses in a locomotor training-based corrective re-self-organization of the maps in various steps of the ladder.

  11. [Universal implementation of pathogen inactivation in labile blood products is a major step towards transfusion safety].

    PubMed

    Cazenave, Jean-Pierre

    2010-12-01

    Transfusion of labile blood products (red cell concentrates, platelet concentrates and plasma) is vital in the absence of alternatives. Patients and doctors have always feared infections transmitted by blood, blood components and blood-derived drugs. It is potentially dangerous to delay implementation of pathogen inactivation in labile blood products pending a perfect process. Universal implementation of pathogen inactivation in labile blood products is a major step towards transfusion safety.

  12. An ultrahigh-resolution mass spectrometry index to estimate natural organic matter lability

    PubMed Central

    D'Andrilli, Juliana; Cooper, William T; Foreman, Christine M; Marshall, Alan G

    2015-01-01

    Rationale Determining the chemical constituents of natural organic matter (NOM) by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICRMS) remains the ultimate measure for probing its source material, evolution, and transport; however, lability and the fate of organic matter (OM) in the environment remain controversial. FTICRMS-derived elemental compositions are presented in this study to validate a new interpretative method to determine the extent of NOM lability from various environments. Methods FTICRMS data collected over the last decade from the same 9.4 tesla instrument using negative electrospray ionization at the National High Magnetic Field Laboratory in Tallahassee, Florida, was used to validate the application of a NOM lability index. Solid-phase extraction cartridges were used to isolate the NOM prior to FTICRMS; mass spectral peaks were calibrated internally by commonly identified NOM homologous series, and molecular formulae were determined for NOM composition and lability analysis. Results A molecular lability boundary (MLB) was developed from the FTICRMS molecular data, visualized from van Krevelen diagrams, dividing the data into more and less labile constituents. NOM constituents above the MLB at H/C ≥1.5 correspond to more labile material, whereas NOM constituents below the MLB, H/C <1.5, exhibit less labile, more recalcitrant character. Of all marine, freshwater, and glacial environments considered for this study, glacial ecosystems were calculated to contain the most labile OM. Conclusions The MLB extends our interpretation of FTICRMS NOM molecular data to include a metric of lability, and generally ranked the OM environments from most to least labile as glacial > marine > freshwater. Applying the MLB is useful not only for individual NOM FTICRMS studies, but also provides a lability threshold to compare and contrast molecular data with other FTICRMS instruments that survey NOM from around the world. Copyright © 2015

  13. The Labile Side of Iron Supplementation in CKD

    PubMed Central

    Cabantchik, Zvi Ioav

    2015-01-01

    The practice of intravenous iron supplementation has grown as nephrologists have gradually moved away from the liberal use of erythropoiesis-stimulating agents as the main treatment for the anemia of CKD. This approach, together with the introduction of large-dose iron preparations, raises the future specter of inadvertent iatrogenic iron toxicity. Concerns have been raised in original studies and reviews about cardiac complications and severe infections that result from long-term intravenous iron supplementation. Regarding the iron preparations specifically, even though all the currently available preparations appear to be relatively safe in the short term, little is known regarding their long-term safety. In this review we summarize current knowledge of iron metabolism with an emphasis on the sources and potentially harmful effects of labile iron, highlight the approaches to identifying labile iron in pharmaceutical preparations and body fluids and its potential toxic role as a pathogenic factor in the complications of CKD, and propose methods for its early detection in at-risk patients. PMID:25999405

  14. Labile neurotoxin in serum of calves with "nervous" coccidiosis.

    PubMed Central

    Isler, C M; Bellamy, J E; Wobeser, G A

    1987-01-01

    Mouse inoculation was used to test for the presence of a toxin in the serum, cerebrospinal fluid, and intestinal contents collected from cases of bovine enteric coccidiosis, with and without neurological signs, and from control calves. Intravenous inoculation of mice with 10 mL/kg of serum from calves showing nervous signs caused effects significantly different from those caused by the inoculation of serum from calves not showing nervous signs and from control calves. The effect was particularly evident in female mice. At this dosage severe neurological signs such as loss of righting reflex, seizures and death occurred only with serum from calves with "nervous coccidiosis". The results suggest that serum from the calves with neurological signs contains a neurotoxin. This toxin appears to be highly labile. It was not present in the cerebrospinal fluid at levels comparable to those in the serum. The significance of this labile neurotoxin with respect to the pathogenesis of the neurological signs associated with bovine enteric coccidiosis is unknown. PMID:2955865

  15. From GCM grid cell to agricultural plot: scale issues affecting modelling of climate impact

    PubMed Central

    Baron, Christian; Sultan, Benjamin; Balme, Maud; Sarr, Benoit; Traore, Seydou; Lebel, Thierry; Janicot, Serge; Dingkuhn, Michael

    2005-01-01

    General circulation models (GCM) are increasingly capable of making relevant predictions of seasonal and long-term climate variability, thus improving prospects of predicting impact on crop yields. This is particularly important for semi-arid West Africa where climate variability and drought threaten food security. Translating GCM outputs into attainable crop yields is difficult because GCM grid boxes are of larger scale than the processes governing yield, involving partitioning of rain among runoff, evaporation, transpiration, drainage and storage at plot scale. This study analyses the bias introduced to crop simulation when climatic data is aggregated spatially or in time, resulting in loss of relevant variation. A detailed case study was conducted using historical weather data for Senegal, applied to the crop model SARRA-H (version for millet). The study was then extended to a 10°N–17° N climatic gradient and a 31 year climate sequence to evaluate yield sensitivity to the variability of solar radiation and rainfall. Finally, a down-scaling model called LGO (Lebel–Guillot–Onibon), generating local rain patterns from grid cell means, was used to restore the variability lost by aggregation. Results indicate that forcing the crop model with spatially aggregated rainfall causes yield overestimations of 10–50% in dry latitudes, but nearly none in humid zones, due to a biased fraction of rainfall available for crop transpiration. Aggregation of solar radiation data caused significant bias in wetter zones where radiation was limiting yield. Where climatic gradients are steep, these two situations can occur within the same GCM grid cell. Disaggregation of grid cell means into a pattern of virtual synoptic stations having high-resolution rainfall distribution removed much of the bias caused by aggregation and gave realistic simulations of yield. It is concluded that coupling of GCM outputs with plot level crop models can cause large systematic errors due to

  16. Landscape-scale analysis of aboveground tree carbon stocks affected by mountain pine beetles in Idaho

    NASA Astrophysics Data System (ADS)

    Bright, B. C.; Hicke, J. A.; Hudak, A. T.

    2012-12-01

    Bark beetle outbreaks kill billions of trees in western North America, and the resulting tree mortality can significantly impact local and regional carbon cycling. However, substantial variability in mortality occurs within outbreak areas. Our objective was to quantify landscape-scale effects of beetle infestations on aboveground carbon (AGC) stocks using field observations and remotely sensed data across a 5054 ha study area that had experienced a mountain pine beetle outbreak. Tree mortality was classified using multispectral imagery that separated green, red, and gray trees, and models relating field observations of AGC to LiDAR data were used to map AGC. We combined mortality and AGC maps to quantify AGC in beetle-killed trees. Thirty-nine per cent of the forested area was killed by beetles, with large spatial variability in mortality severity. For the entire study area, 40-50% of AGC was contained in beetle-killed trees. When considered on a per-hectare basis, 75-89% of the study area had >25% AGC in killed trees and 3-6% of the study area had >75% of the AGC in killed trees. Our results show that despite high variability in tree mortality within an outbreak area, bark beetle epidemics can have a large impact on AGC stocks at the landscape scale.

  17. Pharmacological ascorbate and ionizing radiation (IR) increase labile iron in pancreatic cancer.

    PubMed

    Moser, Justin C; Rawal, Malvika; Wagner, Brett A; Du, Juan; Cullen, Joseph J; Buettner, Garry R

    2013-01-01

    Labile iron, i.e. iron that is weakly bound and is relatively unrestricted in its redox activity, has been implicated in both the pathogenesis as well as treatment of cancer. Two cancer treatments where labile iron may contribute to their mechanism of action are pharmacological ascorbate and ionizing radiation (IR). Pharmacological ascorbate has been shown to have tumor-specific toxic effects due to the formation of hydrogen peroxide. By catalyzing the oxidation of ascorbate, labile iron can enhance the rate of formation of hydrogen peroxide; labile iron can also react with hydrogen peroxide. Here we have investigated the magnitude of the labile iron pool in tumor and normal tissue. We also examined the ability of pharmacological ascorbate and IR to change the size of the labile iron pool. Although a significant amount of labile iron was seen in tumors (MIA PaCa-2 cells in athymic nude mice), higher levels were seen in murine tissues that were not susceptible to pharmacological ascorbate. Pharmacological ascorbate and irradiation were shown to increase the labile iron in tumor homogenates from this murine model of pancreatic cancer. As both IR and pharmacological ascorbate may rely on labile iron for their effects on tumor tissues, our data suggest that pharmacological ascorbate could be used as a radio-sensitizing agent for some radio-resistant tumors.

  18. Large-scale dynamics associated with clustering of extratropical cyclones affecting Western Europe

    NASA Astrophysics Data System (ADS)

    Pinto, Joaquim G.; Gómara, Iñigo; Masato, Giacomo; Dacre, Helen F.; Woollings, Tim; Caballero, Rodrigo

    2014-12-01

    Some recent winters in Western Europe have been characterized by the occurrence of multiple extratropical cyclones following a similar path. The occurrence of such cyclone clusters leads to large socio-economic impacts due to damaging winds, storm surges, and floods. Recent studies have statistically characterized the clustering of extratropical cyclones over the North Atlantic and Europe and hypothesized potential physical mechanisms responsible for their formation. Here we analyze 4 months characterized by multiple cyclones over Western Europe (February 1990, January 1993, December 1999, and January 2007). The evolution of the eddy driven jet stream, Rossby wave-breaking, and upstream/downstream cyclone development are investigated to infer the role of the large-scale flow and to determine if clustered cyclones are related to each other. Results suggest that optimal conditions for the occurrence of cyclone clusters are provided by a recurrent extension of an intensified eddy driven jet toward Western Europe lasting at least 1 week. Multiple Rossby wave-breaking occurrences on both the poleward and equatorward flanks of the jet contribute to the development of these anomalous large-scale conditions. The analysis of the daily weather charts reveals that upstream cyclone development (secondary cyclogenesis, where new cyclones are generated on the trailing fronts of mature cyclones) is strongly related to cyclone clustering, with multiple cyclones developing on a single jet streak. The present analysis permits a deeper understanding of the physical reasons leading to the occurrence of cyclone families over the North Atlantic, enabling a better estimation of the associated cumulative risk over Europe.

  19. Large-scale dynamics associated with clustering of extratropical cyclones affecting Western Europe

    NASA Astrophysics Data System (ADS)

    Pinto, Joaquim G.; Gómara, Iñigo; Masato, Giacomo; Dacre, Helen F.; Woollings, Tim; Caballero, Rodrigo

    2015-04-01

    Some recent winters in Western Europe have been characterized by the occurrence of multiple extratropical cyclones following a similar path. The occurrence of such cyclone clusters leads to large socio-economic impacts due to damaging winds, storm surges, and floods. Recent studies have statistically characterized the clustering of extratropical cyclones over the North Atlantic and Europe and hypothesized potential physical mechanisms responsible for their formation. Here we analyze 4 months characterized by multiple cyclones over Western Europe (February 1990, January 1993, December 1999, and January 2007). The evolution of the eddy driven jet stream, Rossby wave-breaking, and upstream/downstream cyclone development are investigated to infer the role of the large-scale flow and to determine if clustered cyclones are related to each other. Results suggest that optimal conditions for the occurrence of cyclone clusters are provided by a recurrent extension of an intensified eddy driven jet toward Western Europe lasting at least 1 week. Multiple Rossby wave-breaking occurrences on both the poleward and equatorward flanks of the jet contribute to the development of these anomalous large-scale conditions. The analysis of the daily weather charts reveals that upstream cyclone development (secondary cyclogenesis, where new cyclones are generated on the trailing fronts of mature cyclones) is strongly related to cyclone clustering, with multiple cyclones developing on a single jet streak. The present analysis permits a deeper understanding of the physical reasons leading to the occurrence of cyclone families over the North Atlantic, enabling a better estimation of the associated cumulative risk over Europe.

  20. Does temperature affect the accuracy of vented pressure transducer in fine-scale water level measurement?

    NASA Astrophysics Data System (ADS)

    Liu, Z.; Higgins, C. W.

    2015-03-01

    Submersible pressure transducers have been utilized for collecting water level data since the early 1960s. Together with a digital data logger, it is a convenient way to record water level fluctuations for long-term monitoring. Despite the wide use of pressure transducers for water level monitoring, little has been reported regarding their accuracy and performance under field conditions. The effects of temperature fluctuations on the output of vented pressure transducers were considered in this study. The pressure transducers were tested under both laboratory and field conditions. The results of this study indicate that temperature fluctuation has a strong effect on the transducer output. Rapid changes in temperature introduce noise and fluctuations in the water level readings under a constant hydraulic head while the absolute temperature is also related to sensor errors. The former is attributed to venting and the latter is attributed to temperature compensation effects in the strain gauges. Individual pressure transducers responded differently to the thermal fluctuations in the same testing environment. In the field of surface hydrology, especially when monitoring fine-scale water level fluctuations, ignoring or failing to compensate for the temperature effect can introduce considerable error into pressure transducer readings. It is recommended that a performance test for the pressure transducer is conducted before field deployment.

  1. Saharan Dust Deposition May Affect Phytoplankton Growth in the Mediterranean Sea at Ecological Time Scales

    PubMed Central

    Gallisai, Rachele; Peters, Francesc; Volpe, Gianluca; Basart, Sara; Baldasano, José Maria

    2014-01-01

    The surface waters of the Mediterranean Sea are extremely poor in the nutrients necessary for plankton growth. At the same time, the Mediterranean Sea borders with the largest and most active desert areas in the world and the atmosphere over the basin is subject to frequent injections of mineral dust particles. We describe statistical correlations between dust deposition over the Mediterranean Sea and surface chlorophyll concentrations at ecological time scales. Aerosol deposition of Saharan origin may explain 1 to 10% (average 5%) of seasonally detrended chlorophyll variability in the low nutrient-low chlorophyll Mediterranean. Most of the statistically significant correlations are positive with main effects in spring over the Eastern and Central Mediterranean, conforming to a view of dust events fueling needed nutrients to the planktonic community. Some areas show negative effects of dust deposition on chlorophyll, coinciding with regions under a large influence of aerosols from European origin. The influence of dust deposition on chlorophyll dynamics may become larger in future scenarios of increased aridity and shallowing of the mixed layer. PMID:25333783

  2. Why does offspring size affect performance? Integrating metabolic scaling with life-history theory

    PubMed Central

    Pettersen, Amanda K.; White, Craig R.; Marshall, Dustin J.

    2015-01-01

    Within species, larger offspring typically outperform smaller offspring. While the relationship between offspring size and performance is ubiquitous, the cause of this relationship remains elusive. By linking metabolic and life-history theory, we provide a general explanation for why larger offspring perform better than smaller offspring. Using high-throughput respirometry arrays, we link metabolic rate to offspring size in two species of marine bryozoan. We found that metabolism scales allometrically with offspring size in both species: while larger offspring use absolutely more energy than smaller offspring, larger offspring use proportionally less of their maternally derived energy throughout the dependent, non-feeding phase. The increased metabolic efficiency of larger offspring while dependent on maternal investment may explain offspring size effects—larger offspring reach nutritional independence (feed for themselves) with a higher proportion of energy relative to structure than smaller offspring. These findings offer a potentially universal explanation for why larger offspring tend to perform better than smaller offspring but studies on other taxa are needed. PMID:26559952

  3. Saharan dust deposition may affect phytoplankton growth in the Mediterranean sea at ecological time scales.

    PubMed

    Gallisai, Rachele; Peters, Francesc; Volpe, Gianluca; Basart, Sara; Baldasano, José Maria

    2014-01-01

    The surface waters of the Mediterranean Sea are extremely poor in the nutrients necessary for plankton growth. At the same time, the Mediterranean Sea borders with the largest and most active desert areas in the world and the atmosphere over the basin is subject to frequent injections of mineral dust particles. We describe statistical correlations between dust deposition over the Mediterranean Sea and surface chlorophyll concentrations at ecological time scales. Aerosol deposition of Saharan origin may explain 1 to 10% (average 5%) of seasonally detrended chlorophyll variability in the low nutrient-low chlorophyll Mediterranean. Most of the statistically significant correlations are positive with main effects in spring over the Eastern and Central Mediterranean, conforming to a view of dust events fueling needed nutrients to the planktonic community. Some areas show negative effects of dust deposition on chlorophyll, coinciding with regions under a large influence of aerosols from European origin. The influence of dust deposition on chlorophyll dynamics may become larger in future scenarios of increased aridity and shallowing of the mixed layer.

  4. Large-scale brain networks in affective and social neuroscience: towards an integrative functional architecture of the brain.

    PubMed

    Barrett, Lisa Feldman; Satpute, Ajay Bhaskar

    2013-06-01

    Understanding how a human brain creates a human mind ultimately depends on mapping psychological categories and concepts to physical measurements of neural response. Although it has long been assumed that emotional, social, and cognitive phenomena are realized in the operations of separate brain regions or brain networks, we demonstrate that it is possible to understand the body of neuroimaging evidence using a framework that relies on domain general, distributed structure-function mappings. We review current research in affective and social neuroscience and argue that the emerging science of large-scale intrinsic brain networks provides a coherent framework for a domain-general functional architecture of the human brain.

  5. Fish functional traits are affected by hydrodynamics at small spatial scale.

    PubMed

    Bracciali, C; Guzzo, G; Giacoma, C; Dean, J M; Sarà, G

    2016-02-01

    The Mediterranean damselfish Chromis chromis is a species with a broad distribution found both in the Mediterranean Sea and Eastern Atlantic as far south as the coast of Angola. We hypothesized that the species may have significant functional morphological plasticity to adapt along a gradient of environmental conditions. It is a non-migratory zooplanktivorous species and spends the daytime searching for food in the middle of the water column. Therefore, local hydrodynamics could be one of the environmental factors affecting traits of C. chromis with repercussions at the population level. We compared the body condition, individual growth and body shapes of damselfish collected under two different hydrodynamic conditions (low ∼10 cm s(-1) vs. high ∼20 cm s(-1)). Specimens showed higher body condition under high-hydrodynamics, where conditions offered greater amounts of food, which were able to support larger individuals. Individuals smaller than 60-mm were more abundant under low-hydrodynamics. Morphometric analysis revealed that high-hydrodynamics were favored by fish with a more fusiform body shape and body traits developed for propellant swimming.

  6. Fractal Scaling of Particle Size Distribution and Relationships with Topsoil Properties Affected by Biological Soil Crusts

    PubMed Central

    Gao, Guang-Lei; Ding, Guo-Dong; Wu, Bin; Zhang, Yu-Qing; Qin, Shu-Gao; Zhao, Yuan-Yuan; Bao, Yan-Feng; Liu, Yun-Dong; Wan, Li; Deng, Ji-Feng

    2014-01-01

    Background Biological soil crusts are common components of desert ecosystem; they cover ground surface and interact with topsoil that contribute to desertification control and degraded land restoration in arid and semiarid regions. Methodology/Principal Findings To distinguish the changes in topsoil affected by biological soil crusts, we compared topsoil properties across three types of successional biological soil crusts (algae, lichens, and mosses crust), as well as the referenced sandland in the Mu Us Desert, Northern China. Relationships between fractal dimensions of soil particle size distribution and selected soil properties were discussed as well. The results indicated that biological soil crusts had significant positive effects on soil physical structure (P<0.05); and soil organic carbon and nutrients showed an upward trend across the successional stages of biological soil crusts. Fractal dimensions ranged from 2.1477 to 2.3032, and significantly linear correlated with selected soil properties (R2 = 0.494∼0.955, P<0.01). Conclusions/Significance Biological soil crusts cause an important increase in soil fertility, and are beneficial to sand fixation, although the process is rather slow. Fractal dimension proves to be a sensitive and useful index for quantifying changes in soil properties that additionally implies desertification. This study will be essential to provide a firm basis for future policy-making on optimal solutions regarding desertification control and assessment, as well as degraded ecosystem restoration in arid and semiarid regions. PMID:24516668

  7. Psychometric properties of the Positive and Negative Affect Scale for Children (PANAS-C) in children with anxiety disorders.

    PubMed

    Hughes, Alicia A; Kendall, Philip C

    2009-09-01

    This study investigated the psychometric properties of the Positive and Negative Affect Scale for Children (PANAS-C) (Laurent et al. Psychol Asses 1: 326-338, 1999) in a sample of 139 children (ages 7-14 years) diagnosed with a principal anxiety disorder. Results from this study provided support for the convergent validity of the PANAS-C with established measures of childhood anxiety and depression. As predicted, negative affect was significantly associated with measures of anxiety and depression whereas positive affect was associated with depression. However, weaknesses in discriminant validity were found, most notably with regard to social anxiety. Consistent with previous research, social anxiety was significantly associated with low levels of positive affect (PA). Furthermore, results from regression analyses indicated that PA made a significant unique contribution to the prediction of social anxiety as well as depression scores. Findings are discussed with regard to the usefulness of the PANAS-C to differentiate anxiety and depression in children with anxiety disorders.

  8. Factors affecting reproducibility between genome-scale siRNA-based screens

    PubMed Central

    Barrows, Nicholas J.; Le Sommer, Caroline; Garcia-Blanco, Mariano A.; Pearson, James L.

    2011-01-01

    RNA interference-based screening is a powerful new genomic technology which addresses gene function en masse. To evaluate factors influencing hit list composition and reproducibility, we performed two identically designed small interfering RNA (siRNA)-based, whole genome screens for host factors supporting yellow fever virus infection. These screens represent two separate experiments completed five months apart and allow the direct assessment of the reproducibility of a given siRNA technology when performed in the same environment. Candidate hit lists generated by sum rank, median absolute deviation, z-score, and strictly standardized mean difference were compared within and between whole genome screens. Application of these analysis methodologies within a single screening dataset using a fixed threshold equivalent to a p-value ≤ 0.001 resulted in hit lists ranging from 82 to 1,140 members and highlighted the tremendous impact analysis methodology has on hit list composition. Intra- and inter-screen reproducibility was significantly influenced by the analysis methodology and ranged from 32% to 99%. This study also highlighted the power of testing at least two independent siRNAs for each gene product in primary screens. To facilitate validation we conclude by suggesting methods to reduce false discovery at the primary screening stage. In this study we present the first comprehensive comparison of multiple analysis strategies, and demonstrate the impact of the analysis methodology on the composition of the “hit list”. Therefore, we propose that the entire dataset derived from functional genome-scale screens, especially if publicly funded, should be made available as is done with data derived from gene expression and genome-wide association studies. PMID:20625183

  9. Landscape-Scale Factors Affecting Feral Horse Habitat Use During Summer Within The Rocky Mountain Foothills

    NASA Astrophysics Data System (ADS)

    Girard, Tisa L.; Bork, Edward W.; Neilsen, Scott E.; Alexander, Mike J.

    2013-02-01

    Public lands occupied by feral horses in North America are frequently managed for multiple uses with land use conflict occurring among feral horses, livestock, wildlife, and native grassland conservation. The factors affecting habitat use by horses is critical to understand where conflict may be greatest. We related horse presence and abundance to landscape attributes in a GIS to examine habitat preferences using 98 field plots sampled within a portion of the Rocky Mountain Forest Reserve of SW Alberta, Canada. Horse abundance was greatest in grassland and cut block habitats, and lowest in conifer and mixedwood forest. Resource selection probability functions and count models of faecal abundance indicated that horses preferred areas closer to water, with reduced topographic ruggedness, situated farther from forests, and located farther away from primary roads and trails frequented by recreationalists, but closer to small linear features (i.e. cut lines) that may be used as beneficial travel corridors. Horse presence and abundance were closely related to cattle presence during summer, suggesting that both herbivores utilise the same habitats. Estimates of forage biomass removal (44 %) by mid-July were near maximum acceptable levels. In contrast to horse-cattle associations, horses were negatively associated with wild ungulate abundance, although the mechanism behind this remains unclear and warrants further investigation. Our results indicate that feral horses in SW Alberta exhibit complex habitat selection patterns during spring and summer, including overlap in use with livestock. This finding highlights the need to assess and manage herbivore populations consistent with rangeland carrying capacity and the maintenance of range health.

  10. The priming effect: Investigating the role of labile C quantity on subsoil C losses

    NASA Astrophysics Data System (ADS)

    Diochon, Amanda; Kellman, Lisa; Beltrami, Hugo

    2010-05-01

    In a study examining changes in soil organic carbon storage after clearcut harvesting, we previously reported a 50% decline in soil C stocks approximately 30 years after harvesting, with the greatest losses reported below 20 cm in the mineral soil. Physical and biological separation of organic matter indicated that the decline was greatest in the fractions of organic matter that are conceptually thought to be stable. Stable isotope analyses were consistent with increased mineralization post-harvest and we speculated that the deeper stores of C might have been primed by a flush of labile C post harvest. A recent review (Blagodatskyaya and Kuzyakov, 2008) reported that the direction (positive, negative, neutral) of the priming effect may be dependent not only upon the energy content of the added substrate, but the quantity of C added relative to microbial biomass carbon (MBC). In this study we test this hypothesis using a lab-based incubation of soils collected from the surface (0-10 cm) and subsoil (35-50 cm) of an 80 year old red spruce forest. We added 10, 100 and 1000 % C (glucose) relative to MBC and measured the rate of decomposition (microbial respiration) every 5 h for the first week, every 24 h for the second week, weekly for a month and biweekly for two months. After flushing the headspace with CO2 free air, we measured the rate of microbial respiration and the δ13C of the respired C using a Multiflow prep system with a Gilson autosampler coupled to an Isoprime mass spectrometer. We used an isotope-mixing model to partition the sources of respired C and determine the direction of priming. Our findings suggest that the quantity of added C can affect the direction of priming and that the relative priming effect differs between depths, suggesting that soil organic carbon stores in the subsoil are more sensitive to labile C additions.

  11. [Labile iron pool formation in rat's blood under rhabdomyolysis].

    PubMed

    Shandrenko, S H

    2012-01-01

    The labile nonheme iron pool formation in blood under glycerol induced rhabdomyolysis in rats has been investigated. This iron is not included in transferrin, thereby it is redox-active. Rhabdomyolysis was caused by intramuscular injection of 50% glycerol in a dose of 10 ml/kg. In the first day it has been registered that the blood plasma free heme content increased 10 times and the liver heme-oxigenase activity increased 6 times. Plasma redox-active iron pool formation has been registered by EPR method. Such iron was absent in the control group. This iron pool content in the interval from the 1st to the 6st day was more than 2 mg/l and significantly higher than the transferrin iron level. The plasma iron pool unshielded by transferrin may be one of oxidative stress causes.

  12. Lability of renal papillary tissue composition in the rat.

    PubMed Central

    Atherton, J C

    1978-01-01

    1. The acute effects of (a) a minor operative procedure using ether as the anaesthetic, and (b) the administration of 0.9% saline as a single I.V. injection in the conscious rat, on renal tissue composition were studied in hydropenic and normally hydrated rats. 2. The operative procedure and anaesthesia induced a rapid and transient decrease in papillary osmolality in both hydropenic and normally hydrated animals, the important contributing factor being a significant decrease in urea content. 3. Administration of a small volume of saline caused a rapid decrease in urea content, and an increase in water content. 4. It is concluded that papillary composition is extremely labile, large changes being produced by relatively minor experimental procedures. PMID:624997

  13. Chemical leaching methods and measurements of marine labile particulate Fe

    NASA Astrophysics Data System (ADS)

    Revels, B. N.; John, S.

    2012-12-01

    Iron (Fe) is an essential nutrient for life. Yet its low solubility and concentration in the ocean limits marine phytoplankton productivity in many regions of the world. Dissolved phase Fe (<0.4μm) has traditionally been considered the most biologically accessible form, however, the particulate phase (>0.4μm) may contain an important, labile reservoir of Fe that may also be available to phytoplankton. However, concentration data alone cannot elucidate the sources of particulate Fe to the ocean and to what extent particulate iron may support phytoplankton growth. Isotopic analysis of natural particles may help to elucidate the biogeochemical cycling of Fe, though it is important to find a leaching method which accesses bioavailable Fe. Thirty-three different chemical leaches were performed on a marine sediment reference material, MESS-3. The combinations included four different acids (25% acetic acid, 0.01M HCl, 0.5M HCl, 0.1M H2SO4 at pH2), various redox conditions (0.02M hydroxylamine hydrochloride or 0.02M H2O2), three temperatures (25°C, 60°C, 90°C), and three time points (10 minutes, 2 hours, 24 hours). Leached Fe concentrations varied from 1mg/g to 35mg/g, with longer treatment times, stronger acids, and hotter temperatures generally associated with an increase in leached Fe. δ56Fe in these leaches varied from -1.0‰ to +0.2‰. Interestingly, regardless of leaching method used, there was a very similar relationship between the amount of Fe leached from the particles and the δ56Fe of this iron. Isotopically lighter δ56Fe values were associated with smaller amounts of leached Fe whereas isotopically heavier δ56Fe values were associated with larger amounts of leached Fe. Two alternate hypotheses could explain these data. Either, the particles may contain pools of isotopically light Fe that are easily accessed early in dissolution, or isotopically light Fe may be preferentially leached from the particle due to a kinetic isotope effect during dissolution

  14. The role of labile sulfur compounds in thermochemical sulfate reduction

    USGS Publications Warehouse

    Amrani, A.; Zhang, T.; Ma, Q.; Ellis, G.S.; Tang, Y.

    2008-01-01

    The reduction of sulfate to sulfide coupled with the oxidation of hydrocarbons to carbon dioxide, commonly referred to as thermochemical sulfate reduction (TSR), is an important abiotic alteration process that most commonly occurs in hot carbonate petroleum reservoirs. In the present study we focus on the role that organic labile sulfur compounds play in increasing the rate of TSR. A series of gold-tube hydrous pyrolysis experiments were conducted with n-octane and CaSO4 in the presence of reduced sulfur (e.g. H2S, S??, organic S) at temperatures of 330 and 356 ??C under a constant confining pressure. The in-situ pH was buffered to 3.5 (???6.3 at room temperature) with talc and silica. For comparison, three types of oil with different total S and labile S contents were reacted under similar conditions. The results show that the initial presence of organic or inorganic sulfur compounds increases the rate of TSR. However, organic sulfur compounds, such as 1-pentanethiol or diethyldisulfide, were significantly more effective in increasing the rate of TSR than H2S or elemental sulfur (on a mole S basis). The increase in rate is achieved at relatively low concentrations of 1-pentanethiol, less than 1 wt% of the total n-octane, which is comparable to the concentration of organic S that is common in many oils (???0.3 wt%). We examined several potential reaction mechanisms to explain the observed reactivity of organic LSC. First, the release of H2S from the thermal degradation of thiols was discounted as an important mechanism due to the significantly greater reactivity of thiol compared to an equivalent amount of H2S. Second, we considered the generation of olefines in association with the elimination of H2S during thermal degradation of thiols because olefines are much more reactive than n-alkanes during TSR. In our experiments, olefines increased the rate of TSR, but were less effective than 1-pentanethiol and other organic LSC. Third, the thermal decomposition of

  15. The role of labile sulfur compounds in thermochemical sulfate reduction

    NASA Astrophysics Data System (ADS)

    Amrani, Alon; Zhang, Tongwei; Ma, Qisheng; Ellis, Geoffrey S.; Tang, Yongchun

    2008-06-01

    The reduction of sulfate to sulfide coupled with the oxidation of hydrocarbons to carbon dioxide, commonly referred to as thermochemical sulfate reduction (TSR), is an important abiotic alteration process that most commonly occurs in hot carbonate petroleum reservoirs. In the present study we focus on the role that organic labile sulfur compounds play in increasing the rate of TSR. A series of gold-tube hydrous pyrolysis experiments were conducted with n-octane and CaSO4 in the presence of reduced sulfur (e.g. H2S, S°, organic S) at temperatures of 330 and 356 °C under a constant confining pressure. The in-situ pH was buffered to 3.5 (∼6.3 at room temperature) with talc and silica. For comparison, three types of oil with different total S and labile S contents were reacted under similar conditions. The results show that the initial presence of organic or inorganic sulfur compounds increases the rate of TSR. However, organic sulfur compounds, such as 1-pentanethiol or diethyldisulfide, were significantly more effective in increasing the rate of TSR than H2S or elemental sulfur (on a mole S basis). The increase in rate is achieved at relatively low concentrations of 1-pentanethiol, less than 1 wt% of the total n-octane, which is comparable to the concentration of organic S that is common in many oils (∼0.3 wt%). We examined several potential reaction mechanisms to explain the observed reactivity of organic LSC. First, the release of H2S from the thermal degradation of thiols was discounted as an important mechanism due to the significantly greater reactivity of thiol compared to an equivalent amount of H2S. Second, we considered the generation of olefines in association with the elimination of H2S during thermal degradation of thiols because olefines are much more reactive than n-alkanes during TSR. In our experiments, olefines increased the rate of TSR, but were less effective than 1-pentanethiol and other organic LSC. Third, the thermal decomposition of

  16. To Fish or Not to Fish: Factors at Multiple Scales Affecting Artisanal Fishers' Readiness to Exit a Declining Fishery

    PubMed Central

    Daw, Tim M.; Cinner, Joshua E.; McClanahan, Timothy R.; Brown, Katrina; Stead, Selina M.; Graham, Nicholas A. J.; Maina, Joseph

    2012-01-01

    Globally, fisheries are challenged by the combined impacts of overfishing, degradation of ecosystems and impacts of climate change, while fisheries livelihoods are further pressured by conservation policy imperatives. Fishers' adaptive responses to these pressures, such as exiting from a fishery to pursue alternative livelihoods, determine their own vulnerability, as well as the potential for reducing fishing effort and sustaining fisheries. The willingness and ability to make particular adaptations in response to change, such as exiting from a declining fishery, is influenced by economic, cultural and institutional factors operating at scales from individual fishers to national economies. Previous studies of exit from fisheries at single or few sites, offer limited insight into the relative importance of individual and larger-scale social and economic factors. We asked 599 fishers how they would respond to hypothetical scenarios of catch declines in 28 sites in five western Indian Ocean countries. We investigated how socioeconomic variables at the individual-, household- and site-scale affected whether they would exit fisheries. Site-level factors had the greatest influence on readiness to exit, but these relationships were contrary to common predictions. Specifically, higher levels of infrastructure development and economic vitality - expected to promote exit from fisheries - were associated with less readiness to exit. This may be due to site level histories of exit from fisheries, greater specialisation of fishing households, or higher rewards from fishing in more economically developed sites due to technology, market access, catch value and government subsidies. At the individual and household scale, fishers from households with more livelihood activities, and fishers with lower catch value were more willing to exit. These results demonstrate empirically how adaptive responses to change are influenced by factors at multiple scales, and highlight the importance

  17. Factors Affecting the Rate of Penetration of Large-Scale Electricity Technologies: The Case of Carbon Sequestration

    SciTech Connect

    James R. McFarland; Howard J. Herzog

    2007-05-14

    This project falls under the Technology Innovation and Diffusion topic of the Integrated Assessment of Climate Change Research Program. The objective was to better understand the critical variables that affect the rate of penetration of large-scale electricity technologies in order to improve their representation in integrated assessment models. We conducted this research in six integrated tasks. In our first two tasks, we identified potential factors that affect penetration rates through discussions with modeling groups and through case studies of historical precedent. In the next three tasks, we investigated in detail three potential sets of critical factors: industrial conditions, resource conditions, and regulatory/environmental considerations. Research to assess the significance and relative importance of these factors involved the development of a microeconomic, system dynamics model of the US electric power sector. Finally, we implemented the penetration rate models in an integrated assessment model. While the focus of this effort is on carbon capture and sequestration technologies, much of the work will be applicable to other large-scale energy conversion technologies.

  18. Lability criteria for successive metal complexes in steady-state planar diffusion.

    PubMed

    Salvador, José; Puy, Jaume; Galceran, Josep; Cecília, Joan; Town, Raewyn M; van Leeuwen, Herman P

    2006-01-19

    The lability of sequential metal complexes, ML, ML2, ML3, ... , up to a general 1:n metal/ligand stoichiometric ratio is considered for the case of metal ions (M) being accumulated at a surface (analytical sensor or organism). The analytical solution for the steady-state diffusion of M within a sequential complexation scheme allows quantification of the contribution from the dissociation of all of the complex species to the metal flux through the so-called lability degree, xi. A lability degree for each sequential complexation step is also defined which, due to the sequential character of the complexation scheme, depends not only on the proper kinetic constants of the given complexation step but also on the kinetics of the previous ones. When all contributions from the complexes are diffusion limited, the system is fully labile and xi=1. To provide simple lability criteria, the reaction layer approximation is extended to specifically deal with this sequential complexation scheme, so that a reaction layer thickness is defined when the existence of one particular rate-limiting step is assumed. Expressions for the classical lability parameter, L, are formulated using the reaction layer approximation. The change of the lability of the system as the diffusion layer thickness is modified is analyzed in detail. The contribution of the complex flux reflects the evolution of the system from labile to inert as the thickness of the sensor is appropriately decreased.

  19. Knowledge lability: Within-person changes in parental knowledge and their associations with adolescent problem behavior

    PubMed Central

    Lippold, Melissa A.; Fosco, Gregory; Ram, Nilam; Feinberg, Mark E.

    2015-01-01

    Higher levels of parental knowledge about youth activities has been associated with lower levels of youth risky behavior. Yet little is known about how parental knowledge fluctuates during early adolescence and how those fluctuations are associated with the development of problem behavior. We use the term lability to describe within-person fluctuations in knowledge over time with higher lability indicating greater fluctuations in knowledge from year-to-year. This longitudinal study of rural adolescents (N = 840) investigated if change in parental knowledge across four waves of data from Grades 6 to 8 is characterized by lability, and if greater lability is associated with higher youth substance use, delinquency, and internalizing problems in Grade 9. Our models indicated that only some of the variance in parental knowledge was accounted for by developmental trends. The remaining residual variance reflects within-person fluctuations around these trends, lability, plus measurement and occasion-specific error. Even controlling for level and developmental trends in knowledge, higher knowledge lability (i.e., more fluctuation) was associated with increased risk for later alcohol and tobacco use, and for girls, higher delinquency and internalizing problems. Our findings suggest that lability in parental knowledge has unique implications for adolescent outcomes. The discussion focuses on mechanisms that may link knowledge lability to substance use. Interventions may be most effective if they teach parents to consistently and predictably decrease knowledge across early adolescence. PMID:26381431

  20. Elemental composition and functional groups in soil labile organic matter fractions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Labile organic matter fractions are major components involved in nutrient cycle in soil. In this chapter, we examine three labile organic matter fraction: light fraction (LF), humic acid (HA) and fulvic acid (HA) in Alabama cotton soils (ultisol) amended with chemical fertilizer (NH4NO3) and poult...

  1. Multi-scale interactions affecting transport, storage, and processing of solutes and sediments in stream corridors (Invited)

    NASA Astrophysics Data System (ADS)

    Harvey, J. W.; Packman, A. I.

    2010-12-01

    Surface water and groundwater flow interact with the channel geomorphology and sediments in ways that determine how material is transported, stored, and transformed in stream corridors. Solute and sediment transport affect important ecological processes such as carbon and nutrient dynamics and stream metabolism, processes that are fundamental to stream health and function. Many individual mechanisms of transport and storage of solute and sediment have been studied, including surface water exchange between the main channel and side pools, hyporheic flow through shallow and deep subsurface flow paths, and sediment transport during both baseflow and floods. A significant challenge arises from non-linear and scale-dependent transport resulting from natural, fractal fluvial topography and associated broad, multi-scale hydrologic interactions. Connections between processes and linkages across scales are not well understood, imposing significant limitations on system predictability. The whole-stream tracer experimental approach is popular because of the spatial averaging of heterogeneous processes; however the tracer results, implemented alone and analyzed using typical models, cannot usually predict transport beyond the very specific conditions of the experiment. Furthermore, the results of whole stream tracer experiments tend to be biased due to unavoidable limitations associated with sampling frequency, measurement sensitivity, and experiment duration. We recommend that whole-stream tracer additions be augmented with hydraulic and topographic measurements and also with additional tracer measurements made directly in storage zones. We present examples of measurements that encompass interactions across spatial and temporal scales and models that are transferable to a wide range of flow and geomorphic conditions. These results show how the competitive effects between the different forces driving hyporheic flow, operating at different spatial scales, creates a situation

  2. Impacts of labile organic carbon concentration on organic and inorganic nitrogen utilization by a stream biofilm bacterial community.

    PubMed

    Ghosh, Suchismita; Leff, Laura G

    2013-12-01

    In aquatic ecosystems, carbon (C) availability strongly influences nitrogen (N) dynamics. One manifestation of this linkage is the importance in the dissolved organic matter (DOM) pool of dissolved organic nitrogen (DON), which can serve as both a C and an N source, yet our knowledge of how specific properties of DOM influence N dynamics are limited. To empirically examine the impact of labile DOM on the responses of bacteria to DON and dissolved inorganic nitrogen (DIN), bacterial abundance and community composition were examined in controlled laboratory microcosms subjected to various combinations of dissolved organic carbon (DOC), DON, and DIN treatments. Bacterial communities that had colonized glass beads incubated in a stream were treated with various glucose concentrations and combinations of inorganic and organic N (derived from algal exudate, bacterial protein, and humic matter). The results revealed a strong influence of C availability on bacterial utilization of DON and DIN, with preferential uptake of DON under low C concentrations. Bacterial DON uptake was affected by the concentration and by its chemical nature (labile versus recalcitrant). Labile organic N sources (algal exudate and bacterial protein) were utilized equally well as DIN as an N source, but this was not the case for the recalcitrant humic matter DON treatment. Clear differences in bacterial community composition among treatments were observed based on terminal restriction fragment length polymorphisms (T-RFLP) of 16S rRNA genes. C, DIN, and DON treatments likely drove changes in bacterial community composition that in turn affected the rates of DON and DIN utilization under various C concentrations.

  3. Impacts of Labile Organic Carbon Concentration on Organic and Inorganic Nitrogen Utilization by a Stream Biofilm Bacterial Community

    PubMed Central

    Leff, Laura G.

    2013-01-01

    In aquatic ecosystems, carbon (C) availability strongly influences nitrogen (N) dynamics. One manifestation of this linkage is the importance in the dissolved organic matter (DOM) pool of dissolved organic nitrogen (DON), which can serve as both a C and an N source, yet our knowledge of how specific properties of DOM influence N dynamics are limited. To empirically examine the impact of labile DOM on the responses of bacteria to DON and dissolved inorganic nitrogen (DIN), bacterial abundance and community composition were examined in controlled laboratory microcosms subjected to various combinations of dissolved organic carbon (DOC), DON, and DIN treatments. Bacterial communities that had colonized glass beads incubated in a stream were treated with various glucose concentrations and combinations of inorganic and organic N (derived from algal exudate, bacterial protein, and humic matter). The results revealed a strong influence of C availability on bacterial utilization of DON and DIN, with preferential uptake of DON under low C concentrations. Bacterial DON uptake was affected by the concentration and by its chemical nature (labile versus recalcitrant). Labile organic N sources (algal exudate and bacterial protein) were utilized equally well as DIN as an N source, but this was not the case for the recalcitrant humic matter DON treatment. Clear differences in bacterial community composition among treatments were observed based on terminal restriction fragment length polymorphisms (T-RFLP) of 16S rRNA genes. C, DIN, and DON treatments likely drove changes in bacterial community composition that in turn affected the rates of DON and DIN utilization under various C concentrations. PMID:24038688

  4. Lability of trace metals in submerged soils: a column study

    NASA Astrophysics Data System (ADS)

    Nimirciag, Ramona; Ajmone-Marsan, Franco

    2013-04-01

    The reduction of Fe (III) and Mn (IV) and the decomposition of organic matter exert a great influence on the biogeochemical cycles of many trace metals and nutrients in the environment. In the particular case of intermittently submerged soils, metals associated with Fe and Mn oxides become readily available due to the reductive dissolution of Fe and Mn oxides. The effects of oxido-reductive conditions on the release of Cu and Zn from heavy metal contaminated soils and the changes in their chemical speciation were studied. Column experiments were performed, using Rhizon soil moisture samplers inserted at different heights to monitor the mobility and transport of metals in the submerged soil samples. Cu was released in solution immediately, in the first red-ox cycle, either due to the solubilization of Fe and Mn oxides, or to the oxidation of organic matter with which Cu is commonly complexed, or both. During the following reductive half-cycles, the amount of Cu extracted from the soil solution decreased. However, the concentration of Cu in the solution leached from the column, which was percolated in aerobic conditions, increased. Since in the successive red-ox cycles the Eh decreases faster and to lower values, it is possible that Cu might have been removed from pore water by sulfide precipitation during the anaerobic half-cycle and released during the aerobic half-cycle, due to the oxidation of sulfides to sulfates. The release of Zn was similar to the dissolution of Fe and Mn oxyhydroxydes, and the amount extracted by Rhizon and by leaching increased during the four red-ox cycles. The chemical fractionation of the soils was also studied and the results showed that the alternate oxidative-reductive conditions cause, in general, an increase in the lability of trace metals. While Zn speciation suffers little change, Cu showed a much higher exchangeable fraction in the submerged soils, as compared to the initial, not submerged ones. The results of this study indicate

  5. Analysis of matrix effects critical to microbial transport in organic waste-affected soils across laboratory and field scales

    NASA Astrophysics Data System (ADS)

    Unc, Adrian; Goss, Michael J.; Cook, Simon; Li, Xunde; Atwill, Edward R.; Harter, Thomas

    2012-06-01

    Organic waste applications to soil (manure, various wastewaters, and biosolids) are among the most significant sources of bacterial contamination in surface and groundwater. Transport of bacteria through the vadose zone depends on flow path geometry and stability and is mitigated by interaction between soil, soil solution, air-water interfaces, and characteristics of microbial surfaces. After initial entry, the transport through soil depends on continued entrainment of bacteria and resuspension of those retained in the porous structure. We evaluated the retention of bacteria-sized artificial microspheres, varying in diameter and surface charge and applied in different suspending solutions, by a range of sieved soils contained in minicolumns, the transport of hydrophobic bacteria-sized microspheres through undisturbed soil columns as affected by waste type under simulated rainfall, and the field-scale transport of Enterococcus spp. to an unconfined sandy aquifer after the application of liquid manure. Microsphere retention reflected microsphere properties. The soil type and suspending solution affected retention of hydrophilic but not hydrophobic particles. Retention was not necessarily facilitated by manure-microsphere-soil interactions but by manure-soil interactions. Undisturbed column studies confirmed the governing role of waste type on vadose-zone microsphere transport. Filtration theory applied as an integrated analysis of transport across length scales showed that effective collision efficiency depended on the distance of travel. It followed a power law behavior with the power coefficient varying from ˜0.4 over short distances to >0.9 over 1 m (i.e., very little filtration for a finite fraction of biocolloids), consistent with reduced influence of soil solution and biocolloid properties at longer travel distances.

  6. Scales

    MedlinePlus

    Scales are a visible peeling or flaking of outer skin layers. These layers are called the stratum ... Scales may be caused by dry skin, certain inflammatory skin conditions, or infections. Eczema , ringworm , and psoriasis ...

  7. Atmospheric CO2 mole fraction affects stand-scale carbon use efficiency of sunflower by stimulating respiration in light.

    PubMed

    Gong, Xiao Ying; Schäufele, Rudi; Lehmeier, Christoph Andreas; Tcherkez, Guillaume; Schnyder, Hans

    2017-03-01

    Plant carbon-use-efficiency (CUE), a key parameter in carbon cycle and plant growth models, quantifies the fraction of fixed carbon that is converted into net primary production rather than respired. CUE has not been directly measured, partly because of the difficulty of measuring respiration in light. Here, we explore if CUE is affected by atmospheric CO2 . Sunflower stands were grown at low (200 μmol mol(-1) ) or high CO2 (1000 μmol mol(-1) ) in controlled environment mesocosms. CUE of stands was measured by dynamic stand-scale (13) C labelling and partitioning of photosynthesis and respiration. At the same plant age, growth at high CO2 (compared with low CO2 ) led to 91% higher rates of apparent photosynthesis, 97% higher respiration in the dark, yet 143% higher respiration in light. Thus, CUE was significantly lower at high (0.65) than at low CO2 (0.71). Compartmental analysis of isotopic tracer kinetics demonstrated a greater commitment of carbon reserves in stand-scale respiratory metabolism at high CO2 . Two main processes contributed to the reduction of CUE at high CO2 : a reduced inhibition of leaf respiration by light and a diminished leaf mass ratio. This work highlights the relevance of measuring respiration in light and assessment of the CUE response to environment conditions.

  8. Critical factors affecting field-scale losses of nitrogen and phosphorus in spring snowmelt runoff in the canadian prairies.

    PubMed

    Liu, Kui; Elliott, Jane A; Lobb, David A; Flaten, Don N; Yarotski, Jim

    2013-01-01

    A long-term, field-scale study in southern Manitoba, Canada, was used to identify the critical factors controlling yearly transport of nitrogen (N) and phosphorus (P) by snowmelt runoff. Flow monitoring and water sampling for total and dissolved N and P were performed at the edge of field. The flow-weighted mean concentrations and loads of N and P for the early (the first half of yearly total volume of snowmelt runoff), late (the second half of yearly total volume of snowmelt runoff), and yearly snowmelt runoff were calculated as response variables. A data set of management practices, weather variables, and hydrologic variables was generated and used as predictor variables. Partial least squares regression analysis indicated that critical factors affecting the water chemistry of snowmelt runoff depended on the water quality variable and stage of runoff. Management practices within each year, such as nitrogen application rate, number of tillage passes, and residue burial ratio, were critical factors for flow-weighted mean concentration of N, but not for P concentration or nutrient loads. However, the most important factors controlling nutrient concentrations and loads were those related to the volume of runoff, including snow water equivalent, flow rate, and runoff duration. The critical factors identified for field-scale yearly snowmelt losses provide the basis for modeling of nutrient losses in southern Manitoba and potentially throughout areas with similar climate in the northern Great Plains region, and will aid in the design of effective practices to reduce agricultural nonpoint nutrient pollution in downstream waters.

  9. Diversity of ampeloviruses in mealybug and soft scale vectors and in grapevine hosts from leafroll-affected vineyards.

    PubMed

    Fuchs, M; Marsella-Herrick, P; Loeb, G M; Martinson, T E; Hoch, H C

    2009-10-01

    The occurrence and diversity of Grapevine leafroll-associated virus 1 (GLRaV-1) and Grapevine leafroll-associated virus 3 (GLRaV-3) in the soft scales Parthenolecanium corni and Pulvinaria innumerabilis and in the mealybug Pseudococcus maritimus was determined in leafroll-affected vineyards in the Finger Lakes region of New York. Groups of 1 to 4 specimens were collected under loose grapevine bark and tested by reverse-transcription polymerase chain reaction (RT-PCR) for segments of the second diverged copy of the GLRaV-1 coat protein gene or GLRaV-3 heat-shock protein 70-homologue gene. Virus-specific RT-PCR products were amplified from immature insect vectors and adult mealybugs. Single viral amplicons were obtained mostly from immature vectors (35%, 30 of 85) and dual viral amplicons from immature (16%, 10 of 61) and adult (100%, 14 of 14) mealybugs, including individuals. These observations suggested a simultaneous uptake of GLRaV-1 and GLRaV-3 by individual mealybugs. Furthermore, a comparative nucleotide sequence analysis of viral amplicons from soft scales, mealybugs, and grapevines from which vectors were collected showed identical or highly similar haplotypes, indicating that uptake of GLRaV-1 and GLRaV-3 likely occurred by direct feeding of vectors on their host plants.

  10. Release of a single neurotransmitter from an identified interneuron coherently affects motor output on multiple time scales.

    PubMed

    Dacks, Andrew M; Weiss, Klaudiusz R

    2013-05-01

    Neurotransmitters can have diverse effects that occur over multiple time scales often making the consequences of neurotransmission difficult to predict. To explore the consequences of this diversity, we used the buccal ganglion of Aplysia to examine the effects of GABA release by a single interneuron, B40, on the intrinsic properties and motor output of the radula closure neuron B8. B40 induces a picrotoxin-sensitive fast IPSP lasting milliseconds in B8 and a slow EPSP lasting seconds. We found that the excitatory effects of this slow EPSP are also mediated by GABA. Together, these two GABAergic actions structure B8 firing in a pattern characteristic of ingestive programs. Furthermore, we found that repeated B40 stimulation induces a persistent increase in B8 excitability that was occluded in the presence of the GABA B receptor agonist baclofen, suggesting that GABA affects B8 excitability over multiple time scales. The phasing of B8 activity during the feeding motor programs determines the nature of the behavior elicited during that motor program. The persistent increase in B8 excitability induced by B40 biased the activity of B8 during feeding motor programs causing the motor programs to become more ingestive in nature. Thus, a single transmitter released from a single interneuron can have consequences for motor output that are expressed over multiple time scales. Importantly, despite the differences in their signs and temporal characteristics, the three actions of B40 are coherent in that they promote B8 firing patterns that are characteristic of ingestive motor outputs.

  11. Sample storage-induced changes in the quantity and quality of soil labile organic carbon

    PubMed Central

    Sun, Shou-Qin; Cai, Hui-Ying; Chang, Scott X.; Bhatti, Jagtar S.

    2015-01-01

    Effects of sample storage methods on the quantity and quality of labile soil organic carbon are not fully understood even though their effects on basic soil properties have been extensively studied. We studied the effects of air-drying and frozen storage on cold and hot water soluble organic carbon (WSOC). Cold- and hot-WSOC in air-dried and frozen-stored soils were linearly correlated with those in fresh soils, indicating that storage proportionally altered the extractability of soil organic carbon. Air-drying but not frozen storage increased the concentrations of cold-WSOC and carbohydrate in cold-WSOC, while both increased polyphenol concentrations. In contrast, only polyphenol concentration in hot-WSOC was increased by air-drying and frozen storage, suggesting that hot-WSOC was less affected by sample storage. The biodegradability of cold- but not hot-WSOC was increased by air-drying, while both air-drying and frozen storage increased humification index and changed specific UV absorbance of both cold- and hot-WSOC, indicating shifts in the quality of soil WSOC. Our results suggest that storage methods affect the quantity and quality of WSOC but not comparisons between samples, frozen storage is better than air-drying if samples have to be stored, and storage should be avoided whenever possible when studying the quantity and quality of both cold- and hot-WSOC. PMID:26617054

  12. Sample storage-induced changes in the quantity and quality of soil labile organic carbon

    NASA Astrophysics Data System (ADS)

    Sun, Shou-Qin; Cai, Hui-Ying; Chang, Scott X.; Bhatti, Jagtar S.

    2015-11-01

    Effects of sample storage methods on the quantity and quality of labile soil organic carbon are not fully understood even though their effects on basic soil properties have been extensively studied. We studied the effects of air-drying and frozen storage on cold and hot water soluble organic carbon (WSOC). Cold- and hot-WSOC in air-dried and frozen-stored soils were linearly correlated with those in fresh soils, indicating that storage proportionally altered the extractability of soil organic carbon. Air-drying but not frozen storage increased the concentrations of cold-WSOC and carbohydrate in cold-WSOC, while both increased polyphenol concentrations. In contrast, only polyphenol concentration in hot-WSOC was increased by air-drying and frozen storage, suggesting that hot-WSOC was less affected by sample storage. The biodegradability of cold- but not hot-WSOC was increased by air-drying, while both air-drying and frozen storage increased humification index and changed specific UV absorbance of both cold- and hot-WSOC, indicating shifts in the quality of soil WSOC. Our results suggest that storage methods affect the quantity and quality of WSOC but not comparisons between samples, frozen storage is better than air-drying if samples have to be stored, and storage should be avoided whenever possible when studying the quantity and quality of both cold- and hot-WSOC.

  13. Sample storage-induced changes in the quantity and quality of soil labile organic carbon.

    PubMed

    Sun, Shou-Qin; Cai, Hui-Ying; Chang, Scott X; Bhatti, Jagtar S

    2015-11-30

    Effects of sample storage methods on the quantity and quality of labile soil organic carbon are not fully understood even though their effects on basic soil properties have been extensively studied. We studied the effects of air-drying and frozen storage on cold and hot water soluble organic carbon (WSOC). Cold- and hot-WSOC in air-dried and frozen-stored soils were linearly correlated with those in fresh soils, indicating that storage proportionally altered the extractability of soil organic carbon. Air-drying but not frozen storage increased the concentrations of cold-WSOC and carbohydrate in cold-WSOC, while both increased polyphenol concentrations. In contrast, only polyphenol concentration in hot-WSOC was increased by air-drying and frozen storage, suggesting that hot-WSOC was less affected by sample storage. The biodegradability of cold- but not hot-WSOC was increased by air-drying, while both air-drying and frozen storage increased humification index and changed specific UV absorbance of both cold- and hot-WSOC, indicating shifts in the quality of soil WSOC. Our results suggest that storage methods affect the quantity and quality of WSOC but not comparisons between samples, frozen storage is better than air-drying if samples have to be stored, and storage should be avoided whenever possible when studying the quantity and quality of both cold- and hot-WSOC.

  14. Structural Lability of Barley Stripe Mosaic Virus Virions

    PubMed Central

    Semenyuk, Pavel I.; Abashkin, Dmitry A.; Kalinina, Natalya O.; Arutyunyan, Alexsandr M.; Solovyev, Andrey G.; Dobrov, Eugeny N.

    2013-01-01

    Virions of Barley stripe mosaic virus (BSMV) were neglected for more than thirty years after their basic properties were determined. In this paper, the physicochemical characteristics of BSMV virions and virion-derived viral capsid protein (CP) were analyzed, namely, the absorption and intrinsic fluorescence spectra, circular dichroism spectra, differential scanning calorimetry curves, and size distributions by dynamic laser light scattering. The structural properties of BSMV virions proved to be intermediate between those of Tobacco mosaic virus (TMV), a well-characterized virus with rigid rod-shaped virions, and flexuous filamentous plant viruses. The BSMV virions were found to be considerably more labile than expected from their rod-like morphology and a distant sequence relation of the BSMV and TMV CPs. The circular dichroism spectra of BSMV CP subunits incorporated into the virions, but not subunits of free CP, demonstrated a significant proportion of beta-structure elements, which were proposed to be localized mostly in the protein regions exposed on the virion outer surface. These beta-structure elements likely formed during virion assembly can comprise the N- and C-terminal protein regions unstructured in the non-virion CP and can mediate inter-subunit interactions. Based on computer-assisted structure modeling, a model for BSMV CP subunit structural fold compliant with the available experimental data was proposed. PMID:23613760

  15. Continuous flow analysis of labile iron in ice-cores.

    PubMed

    Hiscock, William T; Fischer, Hubertus; Bigler, Matthias; Gfeller, Gideon; Leuenberger, Daiana; Mini, Olivia

    2013-05-07

    The important active and passive role of mineral dust aerosol in the climate and the global carbon cycle over the last glacial/interglacial cycles has been recognized. However, little data on the most important aeolian dust-derived biological micronutrient, iron (Fe), has so far been available from ice-cores from Greenland or Antarctica. Furthermore, Fe deposition reconstructions derived from the palaeoproxies particulate dust and calcium differ significantly from the Fe flux data available. The ability to measure high temporal resolution Fe data in polar ice-cores is crucial for the study of the timing and magnitude of relationships between geochemical events and biological responses in the open ocean. This work adapts an existing flow injection analysis (FIA) methodology for low-level trace Fe determinations with an existing glaciochemical analysis system, continuous flow analysis (CFA) of ice-cores. Fe-induced oxidation of N,N'-dimethyl-p-pheylenediamine (DPD) is used to quantify the biologically more important and easily leachable Fe fraction released in a controlled digestion step at pH ~1.0. The developed method was successfully applied to the determination of labile Fe in ice-core samples collected from the Antarctic Byrd ice-core and the Greenland Ice-Core Project (GRIP) ice-core.

  16. Inactivation of viruses in labile blood derivatives. II. Physical methods

    SciTech Connect

    Horowitz, B.; Wiebe, M.E.; Lippin, A.; Vandersande, J.; Stryker, M.H.

    1985-11-01

    The thermal inactivation of viruses in labile blood derivatives was evaluated by addition of marker viruses (VSV, Sindbis, Sendai, EMC) to anti-hemophilic factor (AHF) concentrates. The rate of virus inactivation at 60 degrees C was decreased by at least 100- to 700-fold by inclusion of 2.75 M glycine and 50 percent sucrose, or 3.0 M potassium citrate, additives which contribute to retention of protein biologic activity. Nonetheless, at least 10(4) infectious units of each virus was inactivated within 10 hours. Increasing the temperature from 60 to 70 or 80 degrees C caused a 90 percent or greater loss in AHF activity. An even greater decline in the rate of virus inactivation was observed on heating AHF in the lyophilized state, although no loss in AHF activity was observed after 72 hours of heating at 60 degrees C. Several of the proteins present in lyophilized AHF concentrates displayed an altered electrophoretic mobility as a result of exposure to 60 degrees C for 24 hours. Exposure of lyophilized AHF to irradiation from a cobalt 60 source resulted in an acceptable yield of AHF at 1.0, but not at 2.0, megarads. At 1 megarad, greater than or equal to 6.0 logs of VSV and 3.3 logs of Sindbis virus were inactivated.

  17. Labile aggregation stimulating substance, free fatty acids, and platelet aggregation.

    PubMed

    Gerrard, J M; White, J G; Krivit, W

    1976-01-01

    Labile aggregation stimulating substance (LASS), an intermediate produced during platelet biosynthesis of PGE2 and PGF2alpha, acts as a physiologic intercellular messenger to promote platelet aggregation and the release reaction. The activity is formed by intact cells after physiologic stimulation or can be generated from platelet membrane fractions after combination with arachidonate. In the present investigation, small amounts of polyunsaturated fatty acids added to an incubation mixture of platelet microsomes and arachidonate were found to significantly inhibit subsequent platelet aggregation. Saturated and mono-unsaturated fatty acids in the same concentrations were without effect. However, in higher concentrations mono-unsaturated fatty acids were found to be inhibitory and stearic acid was found to enhance subsequent platelet aggregation. The inhibition caused by the polyunsaturated fatty acid, linoleate, was shown to be the result of an effect on the production of LASS through an interaction with the platelet enzyme responsible for conversion of arachidonate to LASS. In contrast, stearic acid was found to enhance platelet aggregation by acting on the platelets and not directly on LASS production. The results suggest that small changes in the fatty acid composition of platelet phospholipids could significantly influence platelet reactivity.

  18. The effect of flood events on the partitioning of labile and refractory carbon in the Missouri-Mississippi River system

    NASA Astrophysics Data System (ADS)

    Roe, K. M.; Rosenheim, B. E.; Kolker, A.; Allison, M. A.; Nittrouer, J. A.; Duncan, D. D.; Nyman, J. A.; Butcher, K. A.; Adamic, J. F.

    2009-12-01

    The Missouri-Mississippi River system (MMRS) transports over 40% (4.0 x 109 kg) of the United States's annual input of total organic carbon (OC) from land to the marine environment, yet it is challenging to assess the MMRS’s exact role in the global carbon cycle because of the system’s complexity and temporal variability (i.e. high discharge events and low flow regimes). Determining the relative proportion of labile OC to refractory OC entrained in the MMRS during high and mean flow conditions would lend to the understanding of the MMRS’s role in the flux of carbon between the biospheric and atmospheric reservoirs, which is central to determining the role of anthropogenic CO2 in the global carbon cycle and in climate change. In this study, we investigate the relative proportion of labile OC to refractory OC in the lower MMRS during high and near-mean flow conditions in the springs of 2008 and 2009, respectively. The 2008 spring flood discharged 105 km3 of water, the maximum amount of water ever allowed out of the main channel, at a maximum rate of 4.3 x 104 m3s-1. Events of this scale have occurred only nine times in the past 80 years. Additionally, during the spring 2008 flood, bedload sand and large particulate OC transport rates were observed to increase exponentially. The following spring, high discharge rates returned to near-mean values with a peak discharge of 3.6 x 103 m3s-1. Using radiocarbon age and the thermal stability of organic matter (OM) as a proxy for lability, we evaluate the spectra of ages of particulate OM transported in the lower MMRS during these two flow regimes using a programmed-temperature pyrolysis/combustion system (PTP/CS) coupled with 14C determination. The PTP/CS utilizes the differences in thermal stability of acid insoluble particulate organic matter (AIPOM) to separate different components from the bulk. Employing PTP/CS on bulk AIPOM can complement experiments measuring small proportions of total OM such as compound

  19. DETERMINATION OF APPARENT QUANTUM YIELD SPECTRA FOR THE FORMATION OF BIOLOGICALLY LABILE PHOTOPRODUCTS

    EPA Science Inventory

    Quantum yield spectra for the photochemical formation of biologically labile photoproducts from dissolved organic matter (DOM) have not been available previously, although they would greatly facilitate attempts to model photoproduct formation rates across latitudinal, seasonal, a...

  20. Neuropsychological correlates of emotional lability in children with ADHD

    PubMed Central

    Banaschewski, Tobias; Jennen-Steinmetz, Christine; Brandeis, Daniel; Buitelaar, Jan K.; Kuntsi, Jonna; Poustka, Luise; Sergeant, Joseph A.; Sonuga-Barke, Edmund J.; Frazier-Wood, Alexis C.; Albrecht, Björn; Chen, Wai; Uebel, Henrik; Schlotz, Wolff; van der Meere, Jaap J.; Gill, Michael; Manor, Iris; Miranda, Ana; Mulas, Fernando; Oades, Robert D.; Roeyers, Herbert; Rothenberger, Aribert; Steinhausen, Hans-Christoph; Faraone, Stephen V.; Asherson, Philip

    2012-01-01

    Background Emotional lability (EL) is commonly seen in patients with Attention Deficit/Hyperactivity Disorder (ADHD). The reasons for this association are currently unknown. To address this question we examined the relationship between ADHD and EL symptoms, and performance on a range of neuropsychological tasks to clarify whether EL symptoms are predicted by particular cognitive and/or motivational dysfunctions and whether these associations are mediated by the presence of ADHD symptoms. Methods A large multi-site sample of 424 carefully diagnosed ADHD cases and 564 unaffected siblings and controls aged 6 to 18 years performed a broad neuropsychological test battery, including a Go/No-Go Task, a warned 4-choice Reaction Time task, the Maudsley Index of Childhood Delay Aversion, and Digit span backwards. Neuropsychological variables were aggregated as indices of processing speed, response variability, executive functions, choice impulsivity and the influence of energetic and/or motivational factors. EL and ADHD symptoms were regressed on each neuropsychological variable in separate analyses controlling for age, gender and IQ, and, in subsequent regression analyses, for ADHD and EL symptoms respectively. Results Neuropsychological variables significantly predicted ADHD and EL symptoms with moderate to low regression coefficients. However, the association between neuropsychological parameters on EL disappeared entirely when the effect of ADHD symptoms was taken into account, revealing that the association between the neuropsychological performance measures and EL is completely mediated statistically by variations in ADHD symptoms. Conversely, neuropsychological effects on ADHD symptoms remained after EL symptom severity was taken into account. Conclusions The neuropsychological parameters examined here predict ADHD more strongly than EL. They cannot explain EL symptoms beyond what is already accounted for by ADHD symptom severity. The association between EL and ADHD

  1. Multivariate Statistical Analysis of Labile Trace Elements in H Chondrites: Evidence for Meteoroid Streams

    NASA Astrophysics Data System (ADS)

    Wolf, S. F.; Lipschutz, M. E.

    1992-07-01

    Differences have been observed between meteorite populations with vastly different terrestrial ages, i.e. Antarctic and non-Antarctic meteorite populations (Koeberl and Cassidy, 1991 and references therein). Comparisons of labile trace element contents (Wolf and Lipschutz, 1992) and induced TL parameters (Benoit and Sears, 1992) in samples from Victoria Land and Queen Maud Land, populations which also differ in mean terrestrial age (Nishiizumi et al, 1989), show significant differences consistent with different average thermal histories. These differences are consistent with the proposition that the flux of meteoritic material to Earth varied temporally. Variations in the flux of meteoritic material over time scales of 10^5 10^6 y require the existence of undispersed streams of meteoroids of asteroidal origin which were initially disputed by Wetherill ( 1986) but have since been observed (Olsson-Steele, 1988; Oberst, 1989; Halliday et al. 1990). Orbital evidence for meteoroid and asteroid streams has been independently obtained by others, particularly Halliday et al.(1990) and Drummond (1991). A group of H chondrites of various petrographic types and diverse CRE ages that yielded 16 falls from 1855 until 1895 in the month of May has been proposed to be two co-orbital meteoroid streams with a common source (R. T. Dodd, personal communication). Compositional evidence of a preterrestrial association of the proposed stream members, if it exists, might be observed in the most sensitive indicators of genetic thermal history, the labile trace elements. We report RNAA data for the concentrations of 14 trace elements, mostly labile ones, (Ag, Au, Bi, Cd, Cs, Co, Ga, In, Rb, Sb, Se, Te, Tl, and Zn) in H4-6 ordinary chondrites. Variance of elemental concentrations within a subpopulation, the members of a proposed co-orbital meteorite stream for example, could be expected to be smaller than the variance for the entire population. We utilize multivariate linear regression and

  2. Anatomical variation in Cactaceae and relatives: Trait lability and evolutionary innovation.

    PubMed

    Ogburn, R Matthew; Edwards, Erika J

    2009-02-01

    The cacti have undergone extensive specialization in their evolutionary history, providing an excellent system in which to address large-scale questions of morphological and physiological adaptation. Recent molecular phylogenetic studies suggest that (1) Pereskia, the leafy genus long interpreted as the sister group of all other cacti, is likely paraphyletic, and (2) Cactaceae are nested within a paraphyletic Portulacaceae as a member of the "ACPT" clade (Anacampseroteae, Cactaceae, Portulaca, and Talinum). We collected new data on the vegetative anatomy of the ACPT clade and relatives to evaluate whether patterns in the distributions of traits may provide insight into early events in the evolutionary transition to the cactus life form. Many traits had high levels of homoplasy and were mostly equivocal with regard to infraclade relationships of ACPT, although several characters do lend further support to a paraphyletic Pereskia. These include a thick stem cuticle, prominent stem mucilage cells, and hypodermal calcium oxalate druses, all of which are likely to be important traits for stem water storage and photosynthesis. We hypothesize that high lability of many putative "precursor" traits may have been critical in generating the organismal context necessary for the evolution of an efficient and integrated photosynthetic stem.

  3. Textural and rheological properties of Pacific whiting surimi as affected by nano-scaled fish bone and heating rates.

    PubMed

    Yin, Tao; Park, Jae W

    2015-08-01

    Textural and rheological properties of Pacific whiting (PW) surimi were investigated at various heating rates with the use of nano-scaled fish bone (NFB) and calcium chloride. Addition of NFB and slow heating improved gel strength significantly. Activity of endogenous transglutaminase (ETGase) from PW surimi was markedly induced by both NFB calcium and calcium chloride, showing an optimal temperature at 30°C. Initial storage modulus increased as NFB calcium concentration increased and the same trend was maintained throughout the temperature sweep. Rheograms with temperature sweep at slow heating rate (1°C/min) exhibited two peaks at ∼ 35°C and ∼ 70°C. However, no peak was observed during temperature sweep from 20 to 90°C at fast heating rate (20°C/min). Protein patterns of surimi gels were affected by both heating rate and NFB calcium concentration. Under slow heating, myosin heavy chain intensity decreased with NFB calcium concentration, indicating formation of ε-(γ-glutamyl) lysine cross-links by ETGase and NFB calcium ion.

  4. PAH repartitioning in field-contaminated sediment following removal of the labile chemical fraction.

    PubMed

    Birdwell, Justin E; Thibodeaux, Louis J

    2009-11-01

    The effect of removing the labile chemical fraction associated with sediment particles followed by internal chemical redistribution was examined in a field-contaminated sediment. Using data from desorption equilibrium (organic carbon-water partition coefficients, K(OC)) and kinetic (rate of release) experiments, estimates of polynuclear aromatic hydrocarbon biphasic partitioning and desorption rates for both the labile and nonlabile chemical fractions or organic matter compartments were obtained. Sediment K(OC) values increased between 50 and 150% after removal of the labile chemical fraction. Following depletion of the labile chemical fraction during desorption experiments, sediment was stored 30 and 90 days to allow for chemical redistribution between the labile and nonlabile compartments. The subsequent desorption data indicated repartitioning had occurred with the nonlabile chemical fraction recharging the labile compartment. The results provide evidence that chemical transfer between organic matter compartments, either through interparticle porewater or via direct intraparticle compartmental exchange, is a real phenomenon that occurs over relatively short times (weeks to months). This calls into question the idea that hydrophobic organic pollutants in the nonlabile chemical fraction are sequestered or less bioavailable over the long-term and has implications for water quality impacts during contaminated sediment resuspension events, risk assessment of polluted sites, and selection of sediment remediation strategies.

  5. Heat-labile enterotoxin of Escherichia coli promotes intestinal colonization of Salmonella enterica.

    PubMed

    Verbrugghe, Elin; Van Parys, Alexander; Leyman, Bregje; Boyen, Filip; Arnouts, Sven; Lundberg, Urban; Ducatelle, Richard; Van den Broeck, Wim; Yekta, Maryam Atef; Cox, Eric; Haesebrouck, Freddy; Pasmans, Frank

    2015-12-01

    Enterotoxigenic Escherichia coli (ETEC) is an important cause of infantile and travellers' diarrhoea, which poses a serious health burden, especially in developing countries. In addition, ETEC bacteria are a major cause of illness and death in neonatal and recently weaned pigs. The production of a heat-labile enterotoxin (LT) promotes the colonization and pathogenicity of ETEC and may exacerbate co-infections with other enteric pathogens such as Salmonella enterica. We showed that the intraintestinal presence of LT dramatically increased the intestinal Salmonella Typhimurium load in experimentally inoculated pigs. This could not be explained by direct alteration of the invasion or survival capacity of Salmonella in enterocytes, in vitro. However, we demonstrated that LT affects the enteric mucus layer composition in a mucus-secreting goblet cell line by significantly decreasing the expression of mucin 4. The current results show that LT alters the intestinal mucus composition and aggravates a Salmonella Typhimurium infection, which may result in the exacerbation of the diarrhoeal illness.

  6. Predicting probability of occurrence and factors affecting distribution and abundance of three Ozark endemic crayfish species at multiple spatial scales

    USGS Publications Warehouse

    Nolen, Matthew S.; Magoulick, Daniel D.; DiStefano, Robert J.; Imhoff, Emily M.; Wagner, Brian K.

    2014-01-01

    We found that a range of environmental variables were important in predicting crayfish distribution and abundance at multiple spatial scales and their importance was species-, response variable- and scale dependent. We would encourage others to examine the influence of spatial scale on species distribution and abundance patterns.

  7. Major factors affecting in situ biodegradation rates of jet-fuel during large-scale biosparging project in sedimentary bedrock.

    PubMed

    Machackova, Jirina; Wittlingerova, Zdena; Vlk, Kvetoslav; Zima, Jaroslav

    2012-01-01

    Biodegradation of petroleum hydrocarbons (TPH), mainly jet fuel, had taken place at the former Soviet Army air base in the Czech Republic. The remediation of large-scale petroleum contamination of soil and groundwater has provided valuable information about biosparging efficiency in the sandstone sedimentary bedrock. In 1997 petroleum contamination was found to be present in soil and groundwater across an area of 28 hectares, divided for the clean-up purpose into smaller clean-up fields (several hectares). The total estimated quantity of TPH released to the environment was about 7,000 metric tons. Biosparging was applied as an innovative clean-up technology at the site and was operated over a 10-year period (1997-2008). Importance of a variety of factors that affect bacterial activity in unsaturated and saturated zones was widely studied on the site and influence of natural and technological factors on clean-up efficiency in heavily contaminates areas of clean-up fields (initial contaminant mass 111-452 metric ton/ha) was evaluated. Long-term monitoring of the groundwater temperature has shown seasonal rises and falls of temperature which have caused a fluctuation in biodegradation activity during clean-up. By contrast, an overall rise of average groundwater temperature was observed in the clean-up fields, most probably as a result of the biological activity during the clean-up process. The significant rise of biodegradation rates, observed after air sparging intensification, and strong linear correlation between the air injection rates and biodegradation activities have shown that the air injection rate is the principal factor in biodegradation efficiency in heavily contaminated areas. It has a far more important role for achieving a biodegradation activity than the contamination content which appeared to have had only a slight effect after the removal of about 75% of initial contamination.

  8. In Situ, High-Resolution Profiles of Labile Metals in Sediments of Lake Taihu

    PubMed Central

    Wang, Dan; Gong, Mengdan; Li, Yangyang; Xu, Lv; Wang, Yan; Jing, Rui; Ding, Shiming; Zhang, Chaosheng

    2016-01-01

    Characterizing labile metal distribution and biogeochemical behavior in sediments is crucial for understanding their contamination characteristics in lakes, for which in situ, high-resolution data is scare. The diffusive gradient in thin films (DGT) technique was used in-situ at five sites across Lake Taihu in the Yangtze River delta in China to characterize the distribution and mobility of eight labile metals (Fe, Mn, Zn, Ni, Cu, Pb, Co and Cd) in sediments at a 3 mm spatial resolution. The results showed a great spatial heterogeneity in the distributions of redox-sensitive labile Fe, Mn and Co in sediments, while other metals had much less marked structure, except for downward decreases of labile Pb, Ni, Zn and Cu in the surface sediment layers. Similar distributions were found between labile Mn and Co and among labile Ni, Cu and Zn, reflecting a close link between their geochemical behaviors. The relative mobility, defined as the ratio of metals accumulated by DGT to the total contents in a volume of sediments with a thickness of 10 mm close to the surface of DGT probe, was the greatest for Mn and Cd, followed by Zn, Ni, Cu and Co, while Pb and Fe had the lowest mobility; this order generally agreed with that defined by the modified BCR approach. Further analyses showed that the downward increases of pH values in surface sediment layer may decrease the lability of Pb, Ni, Zn and Cu as detected by DGT, while the remobilization of redox-insensitive metals in deep sediment layer may relate to Mn cycling through sulphide coprecipitation, reflected by several corresponding minima between these metals and Mn. These in situ data provided the possibility for a deep insight into the mechanisms involved in the remobilization of metals in freshwater sediments. PMID:27608033

  9. Lability of drinking water treatment residuals (WTR) immobilized phosphorus: aging and pH effects.

    PubMed

    Agyin-Birikorang, Sampson; O'Connor, George A

    2007-01-01

    Time constraints associated with conducting long-term (>20 yr) field experiments to test the stability of drinking water treatment residuals (WTR) sorbed phosphorus (P) inhibit improved understanding of the fate of sorbed P in soils when important soil properties (e.g., pH) change. We used artificially aged samples to evaluate aging and pH effects on lability of WTR-immobilized P. Artificial aging was achieved through incubation at elevated temperatures (46 or 70 degrees C) for 4.5 yr, and through repeated wetting and drying for 2 yr. Using a modified isotopic ((32)P) dilution technique, coupled with a stepwise acidification procedure, we monitored changes in labile P concentrations over time. This technique enabled evaluation of the effect of pH on the lability of WTR-immobilized P. Within the pH range of 4 to 7, WTR amendment, coupled with artificial aging, ultimately reduced labile P concentrations by > or = 75% relative to the control (no-WTR) samples. Soil samples with different physicochemical properties from two 7.5-yr-old, one-time WTR-amended field sites were utilized to validate the trends observed with the artificially aged samples. Despite the differences in physicochemical properties among the three (two field-aged and one artificially aged) soil samples, similar trends of aging and pH effects on lability of WTR-immobilized P were observed. Labile P concentrations of the WTR-amended field-aged samples of the two sites decreased 6 mo after WTR amendment and the reduction persisted for 7.5 yr, ultimately resulting in > or = 70% reduction, compared to the control plots. We conclude that WTR application is capable of reducing labile P concentration in P-impacted soils, doing so for a long time, and that within the commonly encountered range of pH values for agricultural soils WTR-immobilized P should be stable.

  10. Effect of warming on the degradation and production of low-molecular-weight labile organic carbon in an Arctic tundra soil

    SciTech Connect

    Yang, Ziming; Wullschleger, Stan D.; Liang, Liyuan; Graham, David E.; Gu, Baohua

    2016-01-16

    The fate of soil organic carbon (SOC) stored in the Arctic permafrost is a key concern as temperatures continue to rise in the northern hemisphere. Studies and conceptual models suggest that SOC degradation is affected by the composition of SOC, but it is unclear exactly what portions of SOC are vulnerable to rapid breakdown and what mechanisms may be controlling SOC degradation upon permafrost thaw. Here, we examine the dynamic consumption and production of labile SOC in an anoxic incubation experiment using soil samples from the active layer at the Barrow Environmental Observatory, Barrow, Alaska, USA. Free-reducing sugars, alcohols, and low-molecular-weight (LMW) organic acids were analyzed during incubation at either –2 or 8 °C for up to 240 days. Results show that simple sugar and alcohol SOC largely account for the initial rapid release of CO2 and CH4 through anaerobic fermentation, whereas the fermentation products, acetate and formate, are subsequently utilized as primary substrates for methanogenesis. Iron(III) reduction is correlated to acetate production and methanogenesis, suggesting its important role as an electron acceptor in tundra SOC respiration. These observations are further supported in a glucose addition experiment, in which rapid CO2 and CH4 production occurred concurrently with rapid production and consumption of labile organics such as acetate. However, addition of tannic acid, as a more complex organic substrate, showed little influence on the overall production of CO2 and CH4 and organic acids. Together our study shows that LMW labile organics in SOC control the initial rapid release of green-house gases upon warming. We thus present a conceptual framework for the labile SOC transformations and their relations to fermentation, iron reduction and methanogenesis, thereby providing the basis for improved model prediction of climate feedbacks in the Arctic.

  11. Effect of warming on the degradation and production of low-molecular-weight labile organic carbon in an Arctic tundra soil

    DOE PAGES

    Yang, Ziming; Wullschleger, Stan D.; Liang, Liyuan; ...

    2016-01-16

    The fate of soil organic carbon (SOC) stored in the Arctic permafrost is a key concern as temperatures continue to rise in the northern hemisphere. Studies and conceptual models suggest that SOC degradation is affected by the composition of SOC, but it is unclear exactly what portions of SOC are vulnerable to rapid breakdown and what mechanisms may be controlling SOC degradation upon permafrost thaw. Here, we examine the dynamic consumption and production of labile SOC in an anoxic incubation experiment using soil samples from the active layer at the Barrow Environmental Observatory, Barrow, Alaska, USA. Free-reducing sugars, alcohols, andmore » low-molecular-weight (LMW) organic acids were analyzed during incubation at either –2 or 8 °C for up to 240 days. Results show that simple sugar and alcohol SOC largely account for the initial rapid release of CO2 and CH4 through anaerobic fermentation, whereas the fermentation products, acetate and formate, are subsequently utilized as primary substrates for methanogenesis. Iron(III) reduction is correlated to acetate production and methanogenesis, suggesting its important role as an electron acceptor in tundra SOC respiration. These observations are further supported in a glucose addition experiment, in which rapid CO2 and CH4 production occurred concurrently with rapid production and consumption of labile organics such as acetate. However, addition of tannic acid, as a more complex organic substrate, showed little influence on the overall production of CO2 and CH4 and organic acids. Together our study shows that LMW labile organics in SOC control the initial rapid release of green-house gases upon warming. We thus present a conceptual framework for the labile SOC transformations and their relations to fermentation, iron reduction and methanogenesis, thereby providing the basis for improved model prediction of climate feedbacks in the Arctic.« less

  12. Using High Performance Computing to Understand Roles of Labile and Nonlabile U(VI) on Hanford 300 Area Plume Longevity

    SciTech Connect

    Lichtner, Peter C.; Hammond, Glenn E.

    2012-07-28

    Evolution of a hexavalent uranium [U(VI)] plume at the Hanford 300 Area bordering the Columbia River is investigated to evaluate the roles of labile and nonlabile forms of U(VI) on the longevity of the plume. A high fidelity, three-dimensional, field-scale, reactive flow and transport model is used to represent the system. Richards equation coupled to multicomponent reactive transport equations are solved for times up to 100 years taking into account rapid fluctuations in the Columbia River stage resulting in pulse releases of U(VI) into the river. The peta-scale computer code PFLOTRAN developed under a DOE SciDAC-2 project is employed in the simulations and executed on ORNL's Cray XT5 supercomputer Jaguar. Labile U(VI) is represented in the model through surface complexation reactions and its nonlabile form through dissolution of metatorbernite used as a surrogate mineral. Initial conditions are constructed corresponding to the U(VI) plume already in place to avoid uncertainties associated with the lack of historical data for the waste stream. The cumulative U(VI) flux into the river is compared for cases of equilibrium and multirate sorption models and for no sorption. The sensitivity of the U(VI) flux into the river on the initial plume configuration is investigated. The presence of nonlabile U(VI) was found to be essential in explaining the longevity of the U(VI) plume and the prolonged high U(VI) concentrations at the site exceeding the EPA MCL for uranium.

  13. Mzm1 Influences a Labile Pool of Mitochondrial Zinc Important for Respiratory Function*

    PubMed Central

    Atkinson, Aaron; Khalimonchuk, Oleh; Smith, Pamela; Sabic, Hana; Eide, David; Winge, Dennis R.

    2010-01-01

    Zinc is essential for function of mitochondria as a cofactor for several matrix zinc metalloproteins. We demonstrate that a labile cationic zinc component of low molecular mass exists in the yeast mitochondrial matrix. This zinc pool is homeostatically regulated in response to the cellular zinc status. This pool of zinc is functionally important because matrix targeting of a cytosolic zinc-binding protein reduces the level of labile zinc and interferes with mitochondrial respiratory function. We identified a series of proteins that modulate the matrix zinc pool, one of which is a novel conserved mitochondrial protein designated Mzm1. Mutant mzm1Δ cells have reduced total and labile mitochondrial zinc, and these cells are hypersensitive to perturbations of the labile pool. In addition, mzm1Δ cells have a destabilized cytochrome c reductase (Complex III) without any effects on Complexes IV or V. Thus, we have established that a link exists between Complex III integrity and the labile mitochondrial zinc pool. PMID:20404342

  14. Soil Microbial and Enzymatic Responses to Complex and Labile Nutrient Inputs

    NASA Astrophysics Data System (ADS)

    Allison, S. D.; Vitousek, P. M.

    2003-12-01

    Microbial extracellular enzymes are essential for converting complex organic compounds into smaller molecules that are available for plant and microbial uptake. However, enzyme production represents a substantial resource cost for microbes, and microbes may be under selection to produce enzymes only when benefits exceed costs. We predicted that soil enzyme activities would be highest when complex substrates were abundant, but available nutrients were scarce (large potential benefit from enzyme production). We also predicted that rates of nutrient and carbon mineralization would correspond to observed shifts in enzyme activities. To test these predictions, we added insoluble and available carbon, nitrogen, and phosphorus substrates to soil incubations and measured enzyme activities, CO2 respiration, microbial biomass, and nutrient mineralization. Labile carbon additions increased respiration rates and microbial biomass, while labile nutrient additions were taken up by microbes but did not increase respiration rates. Labile carbon + nitrogen additions increased acid phosphatase activity, while labile nitrogen additions suppressed aminopeptidase activity. Insoluble nutrients caused major increases in enzyme and microbial activities only when added in combination with complementary labile nutrients (e.g. insoluble carbon + available nitrogen and phosphorus). These results indicate that microbes respond to soil nutrient status by changing patterns of extracellular enzyme production. Such changes can allow microbes to access nutrients in complex molecules, but may be limited by the availability of resources to build enzymes.

  15. Quantification of labile heme in live malaria parasites using a genetically encoded biosensor

    PubMed Central

    Abshire, James R.; Rowlands, Christopher J.; Ganesan, Suresh M.; So, Peter T. C.; Niles, Jacquin C.

    2017-01-01

    Heme is ubiquitous, yet relatively little is known about the maintenance of labile pools of this cofactor, which likely ensures its timely bioavailability for proper cellular function. Quantitative analysis of labile heme is of fundamental importance to understanding how nature preserves access to the diverse chemistry heme enables, while minimizing cellular damage caused by its redox activity. Here, we have developed and characterized a protein-based sensor that undergoes fluorescence quenching upon heme binding. By genetically encoding this sensor in the human malarial parasite, Plasmodium falciparum, we have quantified cytosolic labile heme levels in intact, blood-stage parasites. Our findings indicate that a labile heme pool (∼1.6 µM) is stably maintained throughout parasite development within red blood cells, even during a period coincident with extensive hemoglobin degradation by the parasite. We also find that the heme-binding antimalarial drug chloroquine specifically increases labile cytosolic heme, indicative of dysregulation of this homeostatic pool that may be a relevant component of the antimalarial activity of this compound class. We propose that use of this technology under various environmental perturbations in P. falciparum can yield quantitative insights into fundamental heme biology. PMID:28242687

  16. Mechanisms affecting the transport and retention of bacteria, bacteriophage and microspheres in laboratory-scale saturated fractures

    NASA Astrophysics Data System (ADS)

    Seggewiss, G.; Dickson, S. E.

    2013-12-01

    Groundwater is becoming an increasingly important water source due to the ever-increasing demands from agricultural, residential and industrial consumers. In search of more secure sources, wells are routinely finished over large vertical depths in bedrock aquifers, creating new hydraulic pathways and thus increasing the risk of cross contamination. Moreover, hydraulic pathways are also being altered and created by increasing water withdrawal rates from these wells. Currently, it is not well understood how biological contaminants are transported through, and retained in, fractured media thereby making risk assessment and land use decisions difficult. Colloid transport within fractured rock is a complex process with several mechanisms affecting transport and retention, including: advection, hydrodynamic dispersion, diffusion, size exclusion, adsorption, and decay. Several researchers have investigated the transport of bacteria, bacteriophage, and microspheres (both carboxylated and plain) to evaluate the effects of surface properties and size on transport and retention. These studies have suggested that transport is highly dependent on the physico-chemical properties of the particle, the fracture, and the carrying fluid. However, these studies contain little detail regarding the specific mechanisms responsible for transport beyond speculating about their existence. Further, little work has been done to compare the transport of these particulate materials through the same fracture, allowing for direct observations based on particulate size and surface properties. This research examines the similarities and differences in transport and retention between four different particles through two different laboratory-scale, saturated fractures. This work is designed to explore the effects of particle size, surface properties, ionic strength of the carrying solution, and aperture field characteristics on transport and retention in single, saturated fractures. The particulates

  17. Is the distribution of the lancelet Branchiostoma caribaeum affected by sewage discharges? An analysis at multiple scales of variability.

    PubMed

    Barboza, Carlos Alberto de Moura; Hadlich, Heliatrice Louise; Sandrini-Neto, Leonardo; Martins, César de Castro; Lana, Paulo da Cunha

    2013-04-15

    Spatial variation in the density and biomass of Branchiostoma caribaeum was analyzed along a sewage contamination gradient identified by fecal steroids in a subtropical estuary, southern Brazil. Sampling, repeated in the austral winter and summer, followed a hierarchical design nested at four spatial scales (sector>1 km; area>100 m; site>10 m; replicate<1 m). Density and biomass were significantly lower at sites characterized by high concentrations of fecal steroids. The best combinations of variables that explained the biological similarities among sites involved contamination indicators. Most of the variation of biological data was found at the smallest scales and could be related with the sediment texture. Our study highlighted the usefulness of a multi-scale perspective to evaluate distribution patterns of benthic invertebrates as a biological indication of environmental pollution. Gradient analyses at larger spatial scales may be invalidated by the patchy distribution of benthic fauna if they do not account for such small scale variability.

  18. Scales

    ScienceCinema

    Murray Gibson

    2016-07-12

    Musical scales involve notes that, sounded simultaneously (chords), sound good together. The result is the left brain meeting the right brain — a Pythagorean interval of overlapping notes. This synergy would suggest less difference between the working of the right brain and the left brain than common wisdom would dictate. The pleasing sound of harmony comes when two notes share a common harmonic, meaning that their frequencies are in simple integer ratios, such as 3/2 (G/C) or 5/4 (E/C).

  19. Scales

    SciTech Connect

    Murray Gibson

    2007-04-27

    Musical scales involve notes that, sounded simultaneously (chords), sound good together. The result is the left brain meeting the right brain — a Pythagorean interval of overlapping notes. This synergy would suggest less difference between the working of the right brain and the left brain than common wisdom would dictate. The pleasing sound of harmony comes when two notes share a common harmonic, meaning that their frequencies are in simple integer ratios, such as 3/2 (G/C) or 5/4 (E/C).

  20. Comparison of metal lability in air-dried and fresh dewatered drinking water treatment residuals.

    PubMed

    Wang, Changhui; Pei, Yuansheng; Zhao, Yaqian

    2015-01-01

    In this work, the labilities of Al, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Sr, V and Zn in air-dried (for 60 days) and fresh dewatered WTRs were compared using the Toxicity Characteristic Leaching Procedure (TCLP), fractionation, in vitro digestion and a plant enrichment test. The results showed that the air-dried and fresh dewatered WTRs had different properties, e.g., organic matter composition and available nutrients. The air-dried and fresh dewatered WTRs were non-haf zardous according to the TCLP assessment method used in the United States; however, the metals in the two types of WTRs had different lability. Compared with the metals in the fresh dewatered WTRs, those in the air-dried WTRs tended to be in more stable fractions and also exhibited lower bioaccessibility and bioavailability. Therefore, air-drying can decrease the metal lability and thereby reduce the potential metal pollution risk of WTRs.

  1. A reactivity-based probe of the intracellular labile ferrous iron pool

    PubMed Central

    Spangler, Benjamin; Morgan, Charles W.; Fontaine, Shaun D.; Vander Wal, Mark N.; Chang, Christopher J.; Wells, James A.; Renslo, Adam R.

    2016-01-01

    Improved methods for studying intracellular reactive iron(II) are of significant interest for studies of iron metabolism and disease relevant changes in iron homeostasis. Here we describe a highly-selective reactivity-based probe in which Fenton-type reaction with intracellular labile iron(II) leads to unmasking of the aminonucleoside puromycin. Puromycin leaves a permanent and dose-dependent mark on treated cells that can be detected with high sensitivity and precision using the high-content, plate-based immunofluorescence assay described. Using this new probe and screening approach, we detected alteration of cellular labile iron(II) in response extracellular iron conditioning, overexpression of iron storage and/or export proteins, and post-translational regulation of iron export. Finally, we utilized this new tool to demonstrate the presence of augmented labile iron(II) pools in cancer cells as compared to non-tumorigenic cells. PMID:27376690

  2. Adaptation of the staphylococcal coagglutination technique for detection of heat-labile enterotoxin of Escherichia coli.

    PubMed Central

    Brill, B M; Wasilauskas, B L; Richardson, S H

    1979-01-01

    Protein A-containing staphylococci coated with specific antiserum were tested for heat-labile enterotoxin of Escherichia coli. The immunological cross-reactivity of E. coli heat-labile enterotoxin with Vibrio cholerae toxin (choleragen) was the basis for sensitizing stabilized suspensions of the Cowan I strain of Staphylococcus aureus with anticholeragen. Unconcentrated culture supernatant fluid containing E. coli heat-labile enterotoxin produced macroscopic agglutination when mixed with sensitized staphylococci in capillary tubes. A total of 15 toxigenic and 61 nontoxigenic isolates were tested by the staphylococcal coagglutination technique in a coded fashion and found to be in agreement with previous results of the Chinese hamster ovary cell assay and the passive immune hemolysis test. The staphylococcal coagglutination technique is simple, relatively inexpensive to perform, and requires the immunoglobulin fraction of anticholeragen as the only specific reagent. The staphylococcal coagglutination technique appears to have potential for routine use in diagnostic microbiology laboratories. Images PMID:372214

  3. Controls on the composition and lability of dissolved organic matter in Siberia's Kolyma River basin

    NASA Astrophysics Data System (ADS)

    Mann, P. J.; Davydova, A.; Zimov, N.; Spencer, R. G. M.; Davydov, S.; Bulygina, E.; Zimov, S.; Holmes, R. M.

    2012-03-01

    High-latitude northern rivers export globally significant quantities of dissolved organic carbon (DOC) to the Arctic Ocean. Climate change, and its associated impacts on hydrology and potential mobilization of ancient organic matter from permafrost, is likely to modify the flux, composition, and thus biogeochemical cycling and fate of exported DOC in the Arctic. This study examined DOC concentration and the composition of dissolved organic matter (DOM) across the hydrograph in Siberia's Kolyma River, with a particular focus on the spring freshet period when the majority of the annual DOC load is exported. The composition of DOM within the Kolyma basin was characterized using absorbance-derived measurements (absorbance coefficienta330, specific UV absorbance (SUVA254), and spectral slope ratio SR) and fluorescence spectroscopy (fluorescence index and excitation-emission matrices (EEMs)), including parallel factor analyses of EEMs. Increased surface runoff during the spring freshet led to DOM optical properties indicative of terrestrial soil inputs with high humic-like fluorescence, SUVA254, and low SRand fluorescence index (FI). Under-ice waters, in contrast, displayed opposing trends in optical properties representing less aromatic, lower molecular weight DOM. We demonstrate that substantial losses of DOC can occur via biological (˜30% over 28 days) and photochemical pathways (>29% over 14 days), particularly in samples collected during the spring freshet. The emerging view is therefore that of a more dynamic and labile carbon pool than previously thought, where DOM composition plays a fundamental role in controlling the fate and removal of DOC at a pan-Arctic scale.

  4. Factor structure of the happiness-increasing strategies scales (H-ISS): activities and coping strategies in relation to positive and negative affect

    PubMed Central

    2015-01-01

    Background. Previous research (Tkach & Lyubomirsky, 2006) shows that there are eight general happiness-increasing strategies: social affiliation, partying, mental control, goal pursuit, passive leisure, active leisure, religion, and direct attempts. The present study investigates the factor structure of the happiness-increasing strategies scales (H-ISS) and their relationship to positive and negative affect. Method. The present study used participants’ (N = 1,050 and age mean = 34.21 sd = 12.73) responses to the H-ISS in structural equation modeling analyses. Affect was measured using the Positive Affect Negative Affect Schedule. Results. After small modifications we obtained a good model that contains the original eight factors/scales. Moreover, we found that women tend to use social affiliation, mental control, passive leisure, religion, and direct attempts more than men, while men preferred to engage in partying and clubbing more than women. The H-ISS explained significantly the variance of positive affect (R2 = .41) and the variance of negative affect (R2 = .27). Conclusions. Our study is an addition to previous research showing that the factor structure of the happiness-increasing strategies is valid and reliable. However, due to the model fitting issues that arise in the present study, we give some suggestions for improving the instrument. PMID:26157626

  5. Radiation-induced heat-labile sites that convert into DNA double-strand breaks

    NASA Technical Reports Server (NTRS)

    Rydberg, B.; Chatterjee, A. (Principal Investigator)

    2000-01-01

    The yield of DNA double-strand breaks (DSBs) in SV40 DNA irradiated in aqueous solution was found to increase by more than a factor of two as a result of postirradiation incubation of the DNA at 50 degrees C and pH 8.0 for 24 h. This is in agreement with data from studies performed at 37 degrees C that were published previously. Importantly, similar results were also obtained from irradiation of mammalian DNA in agarose plugs. These results suggest that heat-labile sites within locally multiply damaged sites are produced by radiation and are subsequently transformed into DSBs. Since incubation at 50 degrees C is typically employed for lysis of cells in commonly used pulsed-field gel assays for detection of DSBs in mammalian cells, the possibility that heat-labile sites are present in irradiated cells was also studied. An increase in the apparent number of DSBs as a function of lysis time at 50 degrees C was found with kinetics that was similar to that for irradiated DNA, although the magnitude of the increase was smaller. This suggests that heat-labile sites are also formed in the cell. If this is the case, a proportion of DSBs measured by the pulsed-field gel assays may occur during the lysis step and may not be present in the cell as breaks but as heat-labile sites. It is suggested that such sites consist mainly of heat-labile sugar lesions within locally multiply damaged sites. Comparing rejoining of DSBs measured with short and long lysis procedure indicates that the heat-labile sites are repaired with fast kinetics in comparison with repair of the bulk of DSBs.

  6. Labile carbon retention compensates for CO2 released by priming in forest soils.

    PubMed

    Qiao, Na; Schaefer, Douglas; Blagodatskaya, Evgenia; Zou, Xiaoming; Xu, Xingliang; Kuzyakov, Yakov

    2014-06-01

    Increase of belowground C allocation by plants under global warming or elevated CO2 may promote decomposition of soil organic carbon (SOC) by priming and strongly affects SOC dynamics. The specific effects by priming of SOC depend on the amount and frequency of C inputs. Most previous priming studies have investigated single C additions, but they are not very representative for litterfall and root exudation in many terrestrial ecosystems. We evaluated effects of (13)C-labeled glucose added to soil in three temporal patterns: single, repeated, and continuous on dynamics of CO2 and priming of SOC decomposition over 6 months. Total and (13)C labeled CO2 were monitored to analyze priming dynamics and net C balance between SOC loss caused by priming and the retention of added glucose-C. Cumulative priming ranged from 1.3 to 5.5 mg C g(-1) SOC in the subtropical, and from -0.6 to 5.5 mg C g(-1) SOC in the tropical soils. Single addition induced more priming than repeated and continuous inputs. Therefore, single additions of high substrate amounts may overestimate priming effects over the short term. The amount of added glucose C remaining in soil after 6 months (subtropical: 8.1-11.2 mg C g(-1) SOC or 41-56% of added glucose; tropical: 8.7-15.0 mg C g(-1) SOC or 43-75% of glucose) was substantially higher than the net C loss due to SOC decomposition including priming effect. This overcompensation of C losses was highest with continuous inputs and lowest with single inputs. Therefore, raised labile organic C input to soils by higher plant productivity will increase SOC content even though priming accelerates decomposition of native SOC. Consequently, higher continuous input of C belowground by plants under warming or elevated CO2 can increase C stocks in soil despite accelerated C cycling by priming in soils.

  7. Labile carbon concentrations are strongly linked to plant production in Arctic tussock tundra soils

    NASA Astrophysics Data System (ADS)

    Darrouzet-Nardi, A.; Weintraub, M. N.; Euskirchen, E. S.; Steltzer, H.; Sullivan, P.

    2013-12-01

    The exchange of carbon and nutrients between plants and microbes is a key determinant of carbon balance in Arctic soils. Microbes rely on labile plant carbon for the energy they need to produce enzymes that can release nutrients and less energetically favorable carbon from soil organic matter. One of the main mechanisms of carbon transfer is rhizodeposition, the exudation of labile plant carbon such as sugars from roots into the rhizosphere. Despite the importance of this flow of energy and materials from plants to microbes, there have been few attempts to quantify labile carbon pools or fluxes in Arctic soils. To improve our knowledge of labile carbon dynamics in Arctic soils, we address two basic questions: (1) What are the seasonal patterns of labile carbon concentrations? and (2) How do seasonal patterns in labile carbon correlate with plant production, microbial biomass, and soil nutrients? We measured concentrations of total reducing sugars (TRS) in the soil solution of moist acidic tussock tundra on 28 dates during the 2012 growing season in 20 plots of an early snowmelt × warming experiment. We evaluated these total reducing sugar concentrations in the context of eddy flux carbon exchange data, plant NDVI, total dissolved carbon in soils, microbial biomass, and soil nutrients. Though we did not see treatment effects of the snowmelt × warming experiment, we did observe a clear seasonal pattern in TRS concentrations in which they started low at the time of thaw, then built to a maximum value around the time of peak plant physiology in July, followed by a decline as plants senesced. We observed a clear correlation between TRS and gross primary production (GPP). NDVI values also increased with TRS concentrations during the first half of the season and then leveled off as TRS began its decline. These relationships were in contrast to labile N concentrations, which remained at low concentrations all season. Our data suggest that rhizodeposition of labile carbon

  8. How do parcellation size and short-range connectivity affect dynamics in large-scale brain network models?

    PubMed

    Proix, Timothée; Spiegler, Andreas; Schirner, Michael; Rothmeier, Simon; Ritter, Petra; Jirsa, Viktor K

    2016-11-15

    Recent efforts to model human brain activity on the scale of the whole brain rest on connectivity estimates of large-scale networks derived from diffusion magnetic resonance imaging (dMRI). This type of connectivity describes white matter fiber tracts. The number of short-range cortico-cortical white-matter connections is, however, underrepresented in such large-scale brain models. It is still unclear on the one hand, which scale of representation of white matter fibers is optimal to describe brain activity on a large-scale such as recorded with magneto- or electroencephalography (M/EEG) or functional magnetic resonance imaging (fMRI), and on the other hand, to which extent short-range connections that are typically local should be taken into account. In this article we quantified the effect of connectivity upon large-scale brain network dynamics by (i) systematically varying the number of brain regions before computing the connectivity matrix, and by (ii) adding generic short-range connections. We used dMRI data from the Human Connectome Project. We developed a suite of preprocessing modules called SCRIPTS to prepare these imaging data for The Virtual Brain, a neuroinformatics platform for large-scale brain modeling and simulations. We performed simulations under different connectivity conditions and quantified the spatiotemporal dynamics in terms of Shannon Entropy, dwell time and Principal Component Analysis. For the reconstructed connectivity, our results show that the major white matter fiber bundles play an important role in shaping slow dynamics in large-scale brain networks (e.g. in fMRI). Faster dynamics such as gamma oscillations (around 40 Hz) are sensitive to the short-range connectivity if transmission delays are considered.

  9. Small beetle, large-scale drivers: how regional and landscape factors affect outbreaks of the European spruce bark beetle.

    PubMed

    Seidl, Rupert; Müller, Jörg; Hothorn, Torsten; Bässler, Claus; Heurich, Marco; Kautz, Markus

    2015-10-14

    1. Unprecedented bark beetle outbreaks have been observed for a variety of forest ecosystems recently, and damage is expected to further intensify as a consequence of climate change. In Central Europe, the response of ecosystem management to increasing infestation risk has hitherto focused largely on the stand level, while the contingency of outbreak dynamics on large-scale drivers remains poorly understood. 2. To investigate how factors beyond the local scale contribute to the infestation risk from Ips typographus (Col., Scol.), we analysed drivers across seven orders of magnitude in scale (from 10(3) to 10(10) m(2)) over a 23-year period, focusing on the Bavarian Forest National Park. Time-discrete hazard modelling was used to account for local factors and temporal dependencies. Subsequently, beta regression was applied to determine the influence of regional and landscape factors, the latter characterized by means of graph theory. 3. We found that in addition to stand variables, large-scale drivers also strongly influenced bark beetle infestation risk. Outbreak waves were closely related to landscape-scale connectedness of both host and beetle populations as well as to regional bark beetle infestation levels. Furthermore, regional summer drought was identified as an important trigger for infestation pulses. Large-scale synchrony and connectivity are thus key drivers of the recently observed bark beetle outbreak in the area. 4.Synthesis and applications. Our multiscale analysis provides evidence that the risk for biotic disturbances is highly dependent on drivers beyond the control of traditional stand-scale management. This finding highlights the importance of fostering the ability to cope with and recover from disturbance. It furthermore suggests that a stronger consideration of landscape and regional processes is needed to address changing disturbance regimes in ecosystem management.

  10. Small beetle, large-scale drivers: how regional and landscape factors affect outbreaks of the European spruce bark beetle

    PubMed Central

    Seidl, Rupert; Müller, Jörg; Hothorn, Torsten; Bässler, Claus; Heurich, Marco; Kautz, Markus

    2016-01-01

    Summary 1. Unprecedented bark beetle outbreaks have been observed for a variety of forest ecosystems recently, and damage is expected to further intensify as a consequence of climate change. In Central Europe, the response of ecosystem management to increasing infestation risk has hitherto focused largely on the stand level, while the contingency of outbreak dynamics on large-scale drivers remains poorly understood. 2. To investigate how factors beyond the local scale contribute to the infestation risk from Ips typographus (Col., Scol.), we analysed drivers across seven orders of magnitude in scale (from 103 to 1010 m2) over a 23-year period, focusing on the Bavarian Forest National Park. Time-discrete hazard modelling was used to account for local factors and temporal dependencies. Subsequently, beta regression was applied to determine the influence of regional and landscape factors, the latter characterized by means of graph theory. 3. We found that in addition to stand variables, large-scale drivers also strongly influenced bark beetle infestation risk. Outbreak waves were closely related to landscape-scale connectedness of both host and beetle populations as well as to regional bark beetle infestation levels. Furthermore, regional summer drought was identified as an important trigger for infestation pulses. Large-scale synchrony and connectivity are thus key drivers of the recently observed bark beetle outbreak in the area. 4. Synthesis and applications. Our multiscale analysis provides evidence that the risk for biotic disturbances is highly dependent on drivers beyond the control of traditional stand-scale management. This finding highlights the importance of fostering the ability to cope with and recover from disturbance. It furthermore suggests that a stronger consideration of landscape and regional processes is needed to address changing disturbance regimes in ecosystem management. PMID:27041769

  11. Are introspective reaction times affected by the method of time estimation? A comparison of visual analogue scales and reproduction.

    PubMed

    Bryce, Donna; Bratzke, Daniel

    2015-04-01

    In this study, we investigated whether the method of time estimation plays a role in the apparent limits of introspection in dual-task processing. Previous studies showed that when participants reported introspective reaction times after each trial of a dual task by clicking on a visual analogue scale, they appeared to be unaware of the dual-task costs in their performance. However, visual analogue scales have seldom been used in interval estimation, and they may be inappropriate. In the present study, after each dual-task trial, participants reported their introspective reaction times either via a visual analogue scale or via the method of reproduction. The results replicated the previous findings, irrespective of method. That is, even though responses to the second task slowed down with increasing task overlap, this slowing was only very weakly reflected in the introspective reaction times. Thus, the participants' failure to report the objective dual-task costs in their reaction times is a rather robust finding that cannot be attributed to the method employed. However, introspective reaction times reported via visual analogue scales were more closely related to the objective reaction times, suggesting that visual analogue scales are preferable to reproduction. We conclude that introspective reaction times represent the same information regardless of method, but whether that information is temporal in nature is as yet unsettled.

  12. Persistent Long-Term Facilitation at an Identified Synapse Becomes Labile with Activation of Short-Term Heterosynaptic Plasticity

    PubMed Central

    Schacher, Samuel

    2014-01-01

    Short-term and long-term synaptic plasticity are cellular correlates of learning and memory of different durations. Little is known, however, how these two forms of plasticity interact at the same synaptic connection. We examined the reciprocal impact of short-term heterosynaptic or homosynaptic plasticity at sensorimotor synapses of Aplysia in cell culture when expressing persistent long-term facilitation (P-LTF) evoked by serotonin [5-hydroxytryptamine (5-HT)]. Short-term heterosynaptic plasticity induced by 5-HT (facilitation) or the neuropeptide FMRFa (depression) and short-term homosynaptic plasticity induced by tetanus [post-tetanic potentiation (PTP)] or low-frequency stimulation [homosynaptic depression (HSD)] of the sensory neuron were expressed in both control synapses and synapses expressing P-LTF in the absence or presence of protein synthesis inhibitors. All forms of short-term plasticity failed to significantly affect ongoing P-LTF in the absence of protein synthesis inhibitors. However, P-LTF reversed to control levels when either 5-HT or FMRFa was applied in the presence of rapamycin. In contrast, P-LTF was unaffected when either PTP or HSD was evoked in the presence of either rapamycin or anisomycin. These results indicate that synapses expressing persistent plasticity acquire a “new” baseline and functionally express short-term changes as naive synapses, but the new baseline becomes labile following selective activations—heterosynaptic stimuli that evoke opposite forms of plasticity—such that when presented in the presence of protein synthesis inhibitors produce a rapid reversal of the persistent plasticity. Activity-selective induction of a labile state at synapses expressing persistent plasticity may facilitate the development of therapies for reversing inappropriate memories. PMID:24695698

  13. Non-labile silver species in biosolids remain stable throughout 50 years of weathering and ageing.

    EPA Science Inventory

    Increasing commercial use of nanosilver has focussed attention on the fate of silver (Ag) in the wastewater release pathway. This paper reports the speciation and lability of Ag in archived, stockpiled, and contemporary biosolids from the UK, USA and Australia, and indicates that...

  14. Occurrence and abundance of carbohydrates and amino compounds in sequentially extracted labile soil organic matter fractions.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study aimed to investigate the content of carbohydrates and amino compounds in three labile fraction of soil organic matter (SOM). Soil samples were collected from two agricultural fields in southern Italy and the light fraction (LF), the 500–53-µm particulate organic matter (POM) and the mobil...

  15. Endocrine correlates of personality traits: a comparison between emotionally stable and emotionally labile healthy young men.

    PubMed

    Adler, L; Wedekind, D; Pilz, J; Weniger, G; Huether, G

    1997-01-01

    An initial sample of 120 healthy young men was screened by a personality questionnaire and 15 subjects each with highest and lowest scores respectively on emotionality (emotionally labile, EL subjects and emotionally stable, ES subjects) were recruited for a study on the relationship between the degree of emotionality and the basal secretion of stress-sensitive hormones during night-time. The nocturnal urinary excretion of cortisol, testosterone, adrenaline, noradrenaline and melatonin was measured over a period of 5 consecutive nights. The average amounts of each hormone excreted per night were not different between the two extreme groups. The variability of the excretion during the 5 nights of cortisol and testosterone, but not of adrenaline, noradrenaline and melatonin, was significantly higher in EL compared to ES subjects. The larger fluctuations in the nocturnal secretion of these two (and no other) hormones in EL subjects indicate that emotional lability is associated with a more labile regulation of cortisol and testosterone secretion. The observed intraindividual variability of basal stress hormone secretion may contribute to the vast interindividual variability noticed in psychoneuroendocrine stress research, especially in emotionally labile subjects.

  16. Exploring Individual and Item Factors that Affect Assessment Validity for Diverse Learners: Results from a Large-Scale Cognitive Lab

    ERIC Educational Resources Information Center

    Winter, Phoebe C.; Kopriva, Rebecca J.; Chen, Chen-Su; Emick, Jessica E.

    2006-01-01

    A cognitive lab technique (n=156) was used to investigate interactions between individual factors and item factors presumed to affect assessment validity for diverse students, including English language learners. Findings support the concept of "access"--an interaction between specific construct-irrelevant item features and individual…

  17. Factors Affecting the Inter-annual to Centennial Time Scale Variability of All Indian Summer Monsoon Rainfall

    NASA Astrophysics Data System (ADS)

    Malik, Abdul; Brönnimann, Stefan

    2016-04-01

    The All Indian Summer Monsoon Rainfall (AISMR) is highly important for the livelihood of more than 1 billion people living in the Indian sub-continent. The agriculture of this region is heavily dependent on seasonal (JJAS) monsoon rainfall. An early start or a slight delay of monsoon, or an early withdrawal or prolonged monsoon season may upset the farmer's agricultural plans, can cause significant reduction in crop yield, and hence economic loss. Understanding of AISMR is also vital because it is a part of global atmospheric circulation system. Several studies show that AISMR is influenced by internal climate forcings (ICFs) viz. ENSO, AMO, PDO etc. as well as external climate forcings (ECFs) viz. Greenhouse Gases, volcanic eruptions, and Total Solar Irradiance (TSI). We investigate the influence of ICFs and ECFs on AISMR using recently developed statistical technique called De-trended Partial-Cross-Correlation Analysis (DPCCA). DPCCA can analyse a complex system of several interlinked variables. Often, climatic variables, being cross correlated, are simultaneously tele-connected with several other variables and it is not easy to isolate their intrinsic relationship. In the presence of non-stationarities and background signals the calculated correlation coefficients can be overestimated and erroneous. DPCCA method removes the non-stationarities and partials out the influence of background signals from the variables being cross correlated and thus give a robust estimate of correlation. We have performed the analysis using NOAA Reconstructed SSTs and homogenised instrumental AISMR data set from 1854-1999. By employing the DPCCA method we find that there is a statistically insignificant negative intrinsic relation (by excluding the influence of ICFs, and ECFs except TSI) between AISMR and TSI on decadal to centennial time scale. The ICFs considerably modulate the relation between AISMR and solar activity between 50-80 year time scales and transform this relationship

  18. Using isotopic dilution to assess chemical extraction of labile Ni, Cu, Zn, Cd and Pb in soils.

    PubMed

    Garforth, J M; Bailey, E H; Tye, A M; Young, S D; Lofts, S

    2016-07-01

    Chemical extractants used to measure labile soil metal must ideally select for and solubilise the labile fraction, with minimal solubilisation of non-labile metal. We assessed four extractants (0.43 M HNO3, 0.43 M CH3COOH, 0.05 M Na2H2EDTA and 1 M CaCl2) against these requirements. For soils contaminated by contrasting sources, we compared isotopically exchangeable Ni, Cu, Zn, Cd and Pb (EValue, mg kg(-1)), with the concentrations of metal solubilised by the chemical extractants (MExt, mg kg(-1)). Crucially, we also determined isotopically exchangeable metal in the soil-extractant systems (EExt, mg kg(-1)). Thus 'EExt - EValue' quantifies the concentration of mobilised non-labile metal, while 'EExt - MExt' represents adsorbed labile metal in the presence of the extractant. Extraction with CaCl2 consistently underestimated EValue for Ni, Cu, Zn and Pb, while providing a reasonable estimate of EValue for Cd. In contrast, extraction with HNO3 both consistently mobilised non-labile metal and overestimated the EValue. Extraction with CH3COOH appeared to provide a good estimate of EValue for Cd; however, this was the net outcome of incomplete solubilisation of labile metal, and concurrent mobilisation of non-labile metal by the extractant (MExtEValue). The Na2H2EDTA extractant mobilised some non-labile metal in three of the four soils, but consistently solubilised the entire labile fraction for all soil-metal combinations (MExt ≈ EExt). Comparison of EValue, MExt and EExt provides a rigorous means of assessing the underlying action of soil chemical extraction methods and could be used to refine long-standing soil extraction methodologies.

  19. Glaciers as a source of ancient and labile organic matter to the marine environment.

    PubMed

    Hood, Eran; Fellman, Jason; Spencer, Robert G M; Hernes, Peter J; Edwards, Rick; D'Amore, David; Scott, Durelle

    2009-12-24

    Riverine organic matter supports of the order of one-fifth of estuarine metabolism. Coastal ecosystems are therefore sensitive to alteration of both the quantity and lability of terrigenous dissolved organic matter (DOM) delivered by rivers. The lability of DOM is thought to vary with age, with younger, relatively unaltered organic matter being more easily metabolized by aquatic heterotrophs than older, heavily modified material. This view is developed exclusively from work in watersheds where terrestrial plant and soil sources dominate streamwater DOM. Here we characterize streamwater DOM from 11 coastal watersheds on the Gulf of Alaska that vary widely in glacier coverage (0-64 per cent). In contrast to non-glacial rivers, we find that the bioavailability of DOM to marine microorganisms is significantly correlated with increasing (14)C age. Moreover, the most heavily glaciated watersheds are the source of the oldest ( approximately 4 kyr (14)C age) and most labile (66 per cent bioavailable) DOM. These glacial watersheds have extreme runoff rates, in part because they are subject to some of the highest rates of glacier volume loss on Earth. We estimate the cumulative flux of dissolved organic carbon derived from glaciers contributing runoff to the Gulf of Alaska at 0.13 +/- 0.01 Tg yr(-1) (1 Tg = 10(12) g), of which approximately 0.10 Tg is highly labile. This indicates that glacial runoff is a quantitatively important source of labile reduced carbon to marine ecosystems. Moreover, because glaciers and ice sheets represent the second largest reservoir of water in the global hydrologic system, our findings indicate that climatically driven changes in glacier volume could alter the age, quantity and reactivity of DOM entering coastal oceans.

  20. Microbial control of soil organic matter mineralization responses to labile carbon in subarctic climate change treatments.

    PubMed

    Rousk, Kathrin; Michelsen, Anders; Rousk, Johannes

    2016-12-01

    Half the global soil carbon (C) is held in high-latitude systems. Climate change will expose these to warming and a shift towards plant communities with more labile C input. Labile C can also increase the rate of loss of native soil organic matter (SOM); a phenomenon termed 'priming'. We investigated how warming (+1.1 °C over ambient using open top chambers) and litter addition (90 g m(-2)  yr(-1) ) treatments in the subarctic influenced the susceptibility of SOM mineralization to priming, and its microbial underpinnings. Labile C appeared to inhibit the mineralization of C from SOM by up to 60% within hours. In contrast, the mineralization of N from SOM was stimulated by up to 300%. These responses occurred rapidly and were unrelated to microbial successional dynamics, suggesting catabolic responses. Considered separately, the labile C inhibited C mineralization is compatible with previously reported findings termed 'preferential substrate utilization' or 'negative apparent priming', while the stimulated N mineralization responses echo recent reports of 'real priming' of SOM mineralization. However, C and N mineralization responses derived from the same SOM source must be interpreted together: This suggested that the microbial SOM-use decreased in magnitude and shifted to components richer in N. This finding highlights that only considering SOM in terms of C may be simplistic, and will not capture all changes in SOM decomposition. The selective mining for N increased in climate change treatments with higher fungal dominance. In conclusion, labile C appeared to trigger catabolic responses of the resident microbial community that shifted the SOM mining to N-rich components; an effect that increased with higher fungal dominance. Extrapolating from these findings, the predicted shrub expansion in the subarctic could result in an altered microbial use of SOM, selectively mining it for N-rich components, and leading to a reduced total SOM-use.

  1. What does the cook and medley hostility scale measure? Affect, behavior, and attributions in the marital context.

    PubMed

    Smith, T W; Sanders, J D; Alexander, J F

    1990-04-01

    The Cook and Medley (1954) Hostility (Ho) scale has been used in several important studies evaluating potential health consequences of hostility. A relative lack of compelling information about the construct validity of the Ho scale, however, has raised concerns about the appropriate interpretation of previous research. In this study, 60 married couples discussed a low conflict topic, a high conflict topic, and then a second low conflict topic. High Ho men responded to the high conflict topic with significant increases in self-reported anger and anxiety and overt hostile behavior, but low Ho men did not. Furthermore, compared to low Ho men, high Ho men blamed their wives more for their usual disagreements on the high conflict topic and saw their disagreement-engendering behavior as more intentional. Among women, Ho scores were weakly related only to overt hostile behavior. Finally, couples consisting of two low Ho persons displayed a uniquely agreeable interactional style.

  2. A longitudinal test of the Comprehensive Indoor Tanning Expectations Scale: The importance of affective beliefs in predicting indoor tanning behavior.

    PubMed

    Myrick, Jessica Gall; Noar, Seth M; Kelley, Dannielle; Zeitany, Alexandra E; Morales-Pico, Brenda M; Thomas, Nancy E

    2015-07-31

    In order to better understand drivers of dangerous indoor tanning behaviors, researchers developed the Comprehensive Indoor Tanning Expectations scale. To examine the longitudinal effectiveness of Comprehensive Indoor Tanning Expectations, we surveyed young women in the Southeastern United States at two time points (N = 553). The scale demonstrated strong test-retest reliability. Participants who believed indoor tanning would improve their mood and afford social approval were significantly more likely to tan 6 months later, while participants who believed indoor tanning leads to psychological/physical discomfort were significantly less likely to tan 6 months later. Knowing the psychological bases for indoor tanning can inform intervention and message design.

  3. Modeling compensatory responses of ecosystem-scale water fluxes in forests affected by pine and spruce beetle mortality

    NASA Astrophysics Data System (ADS)

    Millar, D.; Ewers, B. E.; Peckham, S. D.; Mackay, D. S.; Frank, J. M.; Massman, W. J.; Reed, D. E.

    2015-12-01

    Mountain pine beetle (Dendroctonus ponderosae) and spruce beetle (Dendroctonus rufipennis) epidemics have led to extensive mortality in lodgepole pine (Pinus contorta) and Engelmann spruce (Picea engelmannii) forests in the Rocky Mountains of the western US. In both of these tree species, mortality results from hydraulic failure within the xylem, due to blue stain fungal infection associated with beetle attack. However, the impacts of these disturbances on ecosystem-scale water fluxes can be complex, owing to their variable and transient nature. In this work, xylem scaling factors that reduced whole-tree conductance were initially incorporated into a forest ecohydrological model (TREES) to simulate the impact of beetle mortality on evapotranspiration (ET) in both pine and spruce forests. For both forests, simulated ET was compared to observed ET fluxes recorded using eddy covariance techniques. Using xylem scaling factors, the model overestimated the impact of beetle mortality, and observed ET fluxes were approximately two-fold higher than model predictions in both forests. The discrepancy between simulated and observed ET following the onset of beetle mortality may be the result of spatial and temporal heterogeneity of plant communities within the foot prints of the eddy covariance towers. Since simulated ET fluxes following beetle mortality in both forests only accounted for approximately 50% of those observed in the field, it is possible that newly established understory vegetation in recently killed tree stands may play a role in stabilizing ecosystem ET fluxes. Here, we further investigate the unaccounted for ET fluxes in the model by breaking it down into multiple cohorts that represent live trees, dying trees, and understory vegetation that establishes following tree mortality.

  4. Examining the Interplay of Processes Across Multiple Time-Scales: Illustration With the Intraindividual Study of Affect, Health, and Interpersonal Behavior (iSAHIB)

    PubMed Central

    Ram, Nilam; Conroy, David E.; Pincus, Aaron L.; Lorek, Amy; Rebar, Amanda; Roche, Michael J.; Coccia, Michael; Morack, Jennifer; Feldman, Josh; Gerstorf, Denis

    2015-01-01

    Human development is characterized by the complex interplay of processes that manifest at multiple levels of analysis and time-scales. We introduce the Intraindividual Study of Affect, Health and Interpersonal Behavior (iSAHIB) as a model for how multiple time-scale study designs facilitate more precise articulation of developmental theory. Combining age heterogeneity, longitudinal panel, daily diary, and experience sampling protocols, the study made use of smartphone and web-based technologies to obtain intensive longitudinal data from 150 persons age 18–89 years as they completed three 21-day measurement bursts (t = 426 bursts, t = 8,557 days) wherein they provided reports on their social interactions (t = 64,112) as they went about their daily lives. We illustrate how multiple time-scales of data can be used to articulate bioecological models of development and the interplay among more ‘distal’ processes that manifest at ‘slower’ time-scales (e.g., age-related differences and burst-to-burst changes in mental health) and more ‘proximal’ processes that manifest at ‘faster’ time-scales (e.g., changes in context that progress in accordance with the weekly calendar and family influence processes). PMID:26989350

  5. A comprehensive factorial design study of variables affecting CaCO3 scaling under magnetic water treatment.

    PubMed

    Alimi, Fathi; Boubakri, Ali; Tlili, Mohamed M; Ben Amor, Mohamed

    2014-01-01

    Magnetic water treatment (MWT) could be an interesting alternative to chemical treatment to prevent scaling and has been used as an antiscaling treatment for domestic and industrial equipment. A two level-three factor (2(3)) full factorial design was used to evaluate the effects of pH (6-7.5), flow rate (0.54-0.94) and application of a magnetic field on the induction time (IT), total precipitation (TP) rate and homogeneous precipitation (HP) rate of calcium carbonate (CaCO3) scale from hard water. The experimental results and statistical analysis show that the pH, flow rate and interaction between pH and magnetic field have negative effects on IT response. In the case of TP rate response, the magnitude of the main influence is attributed to the magnetic field, followed by pH value and their interaction. Flow rate and pH value have a negative effect on HP rate response, but their interaction has a positive effect. Within these factor ranges, these studied responses predicted by the models were in good agreement with the experimental values. The coefficient of determination (R(2)) for reduction time, TP ratio and HP ratio were 97.8%, 99.12% and 99.92%, respectively. These results were analyzed statistically using Minitab 15.

  6. Perceived utility of emotion: the structure and construct validity of the Perceived Affect Utility Scale in a cross-ethnic sample.

    PubMed

    Chow, Philip I; Berenbaum, Howard

    2012-01-01

    This study introduces a new measure of the perceived utility of emotion, which is the degree to which emotions are perceived to be useful in achieving goals. In this study, we administered this new measure, the Perceived Affect Utility Scale (PAUSe), to a sample of 142 European American and 156 East Asian American college students. Confirmatory factor analyses provided support for a new, culturally informed parsing of emotion and for perceived utility of emotion to be distinguishable from ideal affect, a related but separate construct. Next, we explored the potential importance of perceived utility of emotion in cultural research. Through path analyses, we found that: (a) culturally relevant variables (e.g., independence) played a mediating role in the link between ethnic group and perceived utility of emotion; and (b) perceived utility of emotion played a mediating role in the link between culturally relevant variables and ideal affect. In particular, perceived utility of self-centered emotions (e.g., pride) was found to be associated with independence and ideal affect of those same emotions. In contrast, perceived utility of other-centered emotions (e.g., appreciation) was found to be associated with interdependence, dutifulness/self-discipline, and ideal affect of those same emotions. Implications for perceived utility of emotion in understanding cultural factors are discussed.

  7. Eating from the same plate? Revisiting the role of labile carbon inputs in the soil food web.

    PubMed

    de Vries, Franciska T; Caruso, Tancredi

    2016-11-01

    An increasing number of empirical studies are challenging the central fundamentals on which the classical soil food web model is built. This model assumes that bacteria consume labile substrates twice as fast as fungi, and that mycorrhizal fungi do not decompose organic matter. Here, we build on emerging evidence that points to significant consumption of labile C by fungi, and to the ability of ectomycorrhizal fungi to decompose organic matter, to show that labile C constitutes a major and presently underrated source of C for the soil food web. We use a simple model describing the dynamics of a recalcitrant and a labile C pool and their consumption by fungi and bacteria to show that fungal and bacterial populations can coexist in a stable state with large inputs into the labile C pool and a high fungal use of labile C. We propose a new conceptual model for the bottom trophic level of the soil food web, with organic C consisting of a continuous pool rather than two or three distinct pools, and saprotrophic fungi using substantial amounts of labile C. Incorporation of these concepts will increase our understanding of soil food web dynamics and functioning under changing conditions.

  8. Longitudinal changes in intracardiac repolarization lability in patients with implantable cardioverter-defibrillator

    PubMed Central

    Guduru, Abhilash; Lansdown, Jason; Chernichenko, Daniil; Berger, Ronald D.; Tereshchenko, Larisa G.

    2013-01-01

    Background: While it is known that elevated baseline intracardiac repolarization lability is associated with the risk of fast ventricular tachycardia (FVT)/ventricular fibrillation (VF), the effect of its longitudinal changes on the risk of FVT/VF is unknown. Methods and Results: Near-field (NF) right ventricular (RV) intracardiac electrograms (EGMs) were recorded every 3–6 months at rest in 248 patients with structural heart disease [mean age 61.2 ± 13.3; 185(75%) male; 162(65.3%) ischemic cardiomyopathy] and implanted cardioverter-defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D) [201 (81%) primary prevention]. Intracardiac beat-to-beat QT variability index (QTVINF) was measured on NF RV EGM. During the first study phase (median 18 months), participants made on average 2.4 visits. Then remote follow-up was continued for an additional median period of 3 years. Average QTVINF did not change during the first year after ICD implantation (−0.342 ± 0.603 at baseline vs. −0.262 ± 0.552 at 6 months vs. −0.334 ± 0.603 at 12 months); however, it decreased thereafter (−0.510 ± 0.603 at 18 months; P = 0.042). Adjusted population-averaged GEE model showed that the odds of developing FVT/VF increased by 75% for each 1 unit increase in QTVINF. (OR 1.75 [95%CI 1.05–2.92]; P = 0.031). However, individual patient–specific QTVINF trends (increasing, decreasing, flat) varied from patient to patient. For a given patient, the odds of developing FVT/VF were not associated with increasing or decreasing QTVINF over time [OR 1.27; (95%CI 0.05–30.10); P = 0.881]. Conclusion: While on average the odds of FVT/VF increased with an increase in QTVINF, patient-specific longitudinal trends in QTVINF did not affect the odds of FVT/VF. PMID:23964242

  9. Spatial scale and sampling resolution affect measures of gap disturbance in a lowland tropical forest: implications for understanding forest regeneration and carbon storage.

    PubMed

    Lobo, Elena; Dalling, James W

    2014-03-07

    Treefall gaps play an important role in tropical forest dynamics and in determining above-ground biomass (AGB). However, our understanding of gap disturbance regimes is largely based either on surveys of forest plots that are small relative to spatial variation in gap disturbance, or on satellite imagery, which cannot accurately detect small gaps. We used high-resolution light detection and ranging data from a 1500 ha forest in Panama to: (i) determine how gap disturbance parameters are influenced by study area size, and the criteria used to define gaps; and (ii) to evaluate how accurately previous ground-based canopy height sampling can determine the size and location of gaps. We found that plot-scale disturbance parameters frequently differed significantly from those measured at the landscape-level, and that canopy height thresholds used to define gaps strongly influenced the gap-size distribution, an important metric influencing AGB. Furthermore, simulated ground surveys of canopy height frequently misrepresented the true location of gaps, which may affect conclusions about how relatively small canopy gaps affect successional processes and contribute to the maintenance of diversity. Across site comparisons need to consider how gap definition, scale and spatial resolution affect characterizations of gap disturbance, and its inferred importance for carbon storage and community composition.

  10. Predators determine how weather affects the spatial niche of lizard prey: exploring niche dynamics at a fine scale.

    PubMed

    Lopez-Darias, Marta; Schoener, Thomas W; Spiller, David A; Losos, Jonathan B

    2012-12-01

    Although abiotic and biotic factors can interact to shape the spatial niche of a species, studies that explore the interactive effects of both at a local scale are rare. We demonstrate that one of the main axes (perch height) characterizing the spatial niche of a common lizard, Anolis sagrei, varies according to the interactive effects of weather and the activity of a larger predatory lizard, Leiocephalus carinatus. Results were completely consistent: no matter how favorable the weather conditions for using the ground (mainly characterized by temperature, humidity, wind speed, rain), A. sagrei did not do so if the predator was present. Hence, great behavioral plasticity enabled A. sagrei to adjust its use of space very quickly. To the best of our knowledge, these results constitute the first field demonstration for anoles (and possibly for other animals as well) of how time-varying environmental conditions and predator presence interact to produce short-term changes in utilization along a major niche axis.

  11. Does El Niño-Southern Oscillation affect the precipitation in Korea on seasonal time scales?

    NASA Astrophysics Data System (ADS)

    Ho, Chang-Hoi; Choi, Woosuk; Kim, Jinwon; Kim, Maeng-Ki; Yoo, Hee-Dong

    2016-08-01

    A number of studies in the past two decades have attempted to find the relationship between the precipitation in Korea and the El Niño-Southern Oscillation (ENSO) on various time scales. Comprehensive analyses of station precipitation data in Korea for the 61-year period, 1954-2014, in this study show that the effects of ENSO on the seasonal precipitation in Korea are practically negligible. The correlation between summer precipitation and ENSO is insignificant regardless of the intensity, type (e.g., eastern-Pacific or central-Pacific), and stage (e.g., developing, mature, or decaying) of ENSO. Somewhat meaningful correlation between ENSO and precipitation in Korea occurs only in the ENSO-developing fall. Because summer rainfall accounts for over half of the annual total and fall is a dry season in Korea, the overall effects of ENSO on precipitation in Korea are practically nonexistent.

  12. Small scale hydrology in a pristine and an affected peatland: effects of flood water on soil biogeochemistry

    NASA Astrophysics Data System (ADS)

    Vorenhout, Michel; Cusell, Casper

    2014-05-01

    Many peatlands have a water regime of fluctuating water levels. Flooding of peatsoils occurs in several Dutch peatlands. The quality of this floodwater is important for the ecological value of the peatlands. Well known are the eutrophying effects of polluted flood water on the N- and P- limited vegetation. Nutrients can, however, also be released from the soil; anoxic conditions are known to release Fe-bound phosphorus. It is therefore important to focus on small scale hydrology in projects where water levels are manipulated and floodings are induced. Three types of peatlands have been the subject of two separate studies on hydrology, ecological value and soil biogeochemistry. Two pristine sites and one recently restored flood water storage basin were monitored during 2009-2013. These three sites cover the natural range of peatsoils: from floating fens to degraded and fixed peat soils. All sites have peat as the main soil type, but the age and typology differs. The two pristine sites, the Wieden and Weerribben, are characterized by limited natural and/or induced flooding events. These sites have peaty soils. The soils in the Wieden are fixed to the sandy substrate below, the peaty soils in the Weerribben are completely floating on a water layer. The ecological value of the Wieden and the Weerribben is high, but their value may decline due to low variation in water levels. The third site, the Onlanden area, is a large created storm water storage basin. The Onlanden area is a former agricultural area, inhabited since the Medieval period. It has a fixed and rather degraded peaty soil. Large scale restoration of water inlets and dams has created an area that will get flooded at regular intervals. The Onlanden was the subject of an archaeological monitoring project. All sites were equipped with monitoring stations for local and regional water levels, soil moisture and soil redox potential as the indicator for the local biogeochemistry. Cusell et al (2013) studied the

  13. Relationship between the lability of sediment-bound Cd and its bioaccumulation in edible oyster.

    PubMed

    Chakraborty, Parthasarathi; Ramteke, Darwin; Chakraborty, Sucharita; Chennuri, Kartheek; Bardhan, Pratirupa

    2015-11-15

    A linkage between Cd speciation in sediments and its bioaccumulation in edible oyster (Crassostrea sp.) from a tropical estuarine system was established. Bioaccumulation of Cd in edible oyster increased with the increasing lability and dissociation rate constants of Cd-sediment complexes in the bottom sediments. Total Cd concentration in sediment was not a good indicator of Cd-bioavailability. Increasing trace metal competition in sediments increased lability and bioavailability of Cd in the tropical estuarine sediment. Low thermodynamic stability and high bioavailability of Cd in the estuarine sediment were responsible for high bioaccumulation of Cd in edible oysters (3.2-12.2mgkg(-1)) even though the total concentration of Cd in the bottom sediment was low (0.17-0.49mgkg(-1)).

  14. Factors Affecting Process Temperature and Biogas Production in Small-scale Rural Biogas Digesters in Winter in Northern Vietnam

    PubMed Central

    Pham, C. H.; Vu, C. C.; Sommer, S. G.; Bruun, S.

    2014-01-01

    This study investigated the main factors influencing digester temperature and methods to reduce heat losses during the cold season in the subtropics. Four composite digesters (two insulated and two uninsulated) were buried underground to measure their internal temperature (°C) at a depth of 140 cm and 180 cm, biogas production and methane (CH4) concentration in biogas from August to February. In parallel the temperature of the air (100 cm above ground), in the slurry mixing tank and in the soil (10, 100, 140, and 180 cm depth) was measured by thermocouple. The influent amount was measured daily and the influent chemical composition was measured monthly during the whole experimental period. Seasonal variations in air temperature significantly affected the temperature in the soil, mixing tank and digester. Consequently, biogas production, which is temperature dependent, was influenced by the season. The main factors determining the internal temperature in the digesters were insulation with Styrofoam, air temperature and temperature of slurry in the mixing tank. Biogas production is low due to the cold climate conditions in winter in Northern Vietnam, but the study proved that storing slurry in the mixing tank until its temperature peak at around 14:00 h will increase the temperature in the digester and thus increase potential biogas production. Algorithms are provided linking digester temperature to the temperature of slurry in the mixing tank. PMID:25050049

  15. Spatial Correlation of Soil Organic Matter and Pedogenic Oxides in Permafrost-Affected Soils of Northern Siberia at the Profile Scale

    NASA Astrophysics Data System (ADS)

    Evgrafova, Alevtina; Haase, Ina; Guggenberger, Georg; Shibistova, Olga; Tananaev, Nikita; Mann, Brigitte; Sauheitl, Leopold; Spielvogel, Sandra

    2015-04-01

    The organic carbon (OC) and nitrogen (N) of permafrost-affected soils are highly vulnerable to warming brought on by climate change. Detailed research on the pedogenesis and soil properties of permafrost-affected soils plays a key role in characterizing and quantifying the terrestrial carbon and N cycles. This study was carried out in northern Siberia, at the Little Grawiika Creek catchment (67°28.933' N, 86°25.682' E) that is located on the eastern riverside of the Yenisei River, Krasnoyarsk Krai, Russian Federation. The aim of the study was to conduct research focused on the spatial distribution and relationship of OC and N in permafrost-affected soils that were divided into four groups based on the depth of permafrost table. 13 pits were opened to the depth of their respective permafrost table and the spatially referenced soil samples were collected, each within an 80 cm wide grid and 10 cm mesh size to obtain a high spatial resolution. In order to quantify the spatial distribution and spatial correlation of OC and N stocks in permafrost-affected soils at the profile scale, geostatistical approaches such as simple kriging, ordinary kriging, universal kriging and ordinary cokriging were applied and compared by cross validation. Spatial analysis of pH, content of pedogenic oxides, soil structure and vegetation data were used to determine their influence on the distribution of OC and N stocks at the profile scale. The quality of the OC and N distribution maps is enhanced considerably by cokriging as compared to distribution maps which use simple, ordinary or universal kriging approaches; this is demonstrated by distinctly lower root mean square errors. The nugget-to-sill ratio decreases with an increase in active layer depth, which confirms that vertical variability of soil OC and N stocks decreases with permafrost thaw. Moreover, the range of autocorrelation of OC and N stocks increases considerably with active layer depth.

  16. Mayolenes: labile defensive lipids from the glandular hairs of a caterpillar (Pieris rapae).

    PubMed

    Smedley, Scott R; Schroeder, Frank C; Weibel, Douglas B; Meinwald, Jerrold; Lafleur, Katie A; Renwick, J Alan; Rutowski, Ronald; Eisner, Thomas

    2002-05-14

    Larvae of the European cabbage butterfly, Pieris rapae (Pieridae), are beset with glandular hairs, bearing droplets of a clear oily secretion at their tip. The fluid consists primarily of a series of chemically labile, unsaturated lipids, the mayolenes, which are derived from 11-hydroxylinolenic acid. In bioassays with the ant Crematogaster lineolata, the secretion was shown to be potently deterrent, indicating that the fluid plays a defensive role in nature.

  17. Labile iron potentiates ascorbate-dependent reduction and mobilization of ferritin iron.

    PubMed

    Badu-Boateng, Charles; Pardalaki, Sofia; Wolf, Claude; Lajnef, Sonia; Peyrot, Fabienne; Naftalin, Richard J

    2017-03-21

    Ascorbate mobilizes iron from equine spleen ferritin by two separate processes. Ascorbate alone mobilizes ferritin iron with an apparent Km (ascorbate) ≈1.5mM. Labile iron >2μM, complexed with citrate (10mM), synergises ascorbate-dependent iron mobilization by decreasing the apparent Km (ascorbate) to ≈270μM and raising maximal mobilization rate by ≈5-fold. Catalase reduces the apparent Km(ascorbate) for both ascorbate and ascorbate+iron dependent mobilization by ≈80%. Iron mobilization by ascorbate alone has a higher activation energy (Ea=45.0±5.5kJ/mole) than when mediated by ascorbate with labile iron (10μM) (Ea=13.7±2.2kJ/mole); also mobilization by iron-ascorbate has a three-fold higher pH sensitivity (pH range 6.0-8.0) than with ascorbate alone. Hydrogen peroxide inhibits ascorbate's iron mobilizing action. EPR and autochemiluminescence studies show that ascorbate and labile iron within ferritin enhances radical formation, whereas ascorbate alone produces negligible radicals. These findings suggest that iron catalysed single electron transfer reactions from ascorbate, involving ascorbate or superoxide and possibly ferroxidase tyrosine radicals, accelerate iron mobilization from the ferroxidase centre more than EPR silent, bi-dentate two-electron transfers. These differing modes of electron transference from ascorbate mirror the known mono and bidentate oxidation reactions of dioxygen and hydrogen peroxide with di-ferrous iron at the ferroxidase centre. This study implies that labile iron, at physiological pH, complexed with citrate, synergises iron mobilization from ferritin by ascorbate (50-4000μM). This autocatalytic process can exacerbate oxidative stress in ferritin-containing inflamed tissue.

  18. Immunological Interrelationships of Coliform Heat-Labile and Heat-Stable Enterotoxins

    DTIC Science & Technology

    1981-09-01

    FA, Engert RF: Immunological interrelationships between cholera toxin and the heat -labile and hoat-stable enterotoxins of coliform bacteria . Infec...When Date Enterd) -3- SUMMARY These investigations (a) established the fact that species of coliform bacteria other than ETEC strains of E. coZi...elaborate enterotoxins which alter gastrointestinal physiology, and (b) showed that immunization with either E. coli (ETEC) LT or ST toxin arouses an

  19. Immunologic Interrelationships of Coliform Heat-Labile and Heat-Stable Enterotoxins

    DTIC Science & Technology

    1980-01-15

    immunization program to prevent diarrheal disease due to Intestinal contamination by enterotoxigenic straing of coliform bacteria . We have found that...pnotobiotic rats are challenged by intestinal contamination with strains of E. coli which produce the heat-labile toxin , FOB W 13 -niouos wI, soov esis...extended protection against challenge with either this toxin or viable strains of LT-producing E. coZi. Current investigations are addressed at

  20. Labile and stabilised fractions of soil organic carbon in some intensively cultivated alluvial soils.

    PubMed

    Verma, B C; Datta, S P; Rattan, R K; Singh, A K

    2013-11-01

    The present investigation was undertaken in view of the limited information on the relative proportion of labile and stabilized fractions of soil organic carbon (SOC) in intensively cultivated lands, particularly under tropics. The specific objectives were i) to study the comparative recovery of SOC by different methods of labile carbon estimation under intensively cultivated lands and ii) to evaluate the impact of agricultural practices on carbon management index. For this purpose, in all, 105 surface soil samples were collected from intensively cultivated tube well and sewage irrigated agricultural lands. These samples were analysed for total as well as labile pools of SOC. Results indicated that Walkley and Black, KMnO4-oxidizable and microbial biomass carbon constituted the total SOC to the extent of 10.2 to 47.4, 1.66 to 23.2 and 0.30 to 5.49%, respectively with the corresponding mean values of 26.2, 9.16 and 2.15%. Lability of SOC was considerably higher in sewage irrigated soils than tube well irrigated soils under intensive cropping. Under soybean-wheat, the higher values of carbon management index (CMI) (279 and 286) were associated with the treatments where entire amount of nitrogen was supplied through FYM. Similar results were obtained under rice-wheat, whereas in case of maize-wheat the highest value of CMI was recorded under treatment receiving NPK through chemical fertilizer along with green manure. There was also a significant improvement in CMI under integrated (chemical fertilizer + organics) and chemical fertilizer-treated plots. The values of CMI ranged from 220 to 272 under cultivated lands receiving irrigation through sewage and industrial effluents.

  1. Mechanism-based design of labile precursors for chromium(I) chemistry

    DOE PAGES

    Akturk, Eser S.; Yap, Glenn P. A.; Theopold, Klaus H.

    2015-08-27

    Here, we report that dinitrogen complexes of the type TpR,RCr–N2–CrTpR,R are not the most labile precursors for Cr(I) chemistry, as they are sterically protected from obligatory associative ligand substitution. A mononuclear alkyne complex – TptBu,MeCr(η2-C2(SiMe3)2) – proved to be much more reactive.

  2. A Solvent-Free Thermosponge Nanoparticle Platform for Efficient Delivery of Labile Proteins

    PubMed Central

    2015-01-01

    Protein therapeutics have gained attention recently for treatment of a myriad of human diseases due to their high potency and unique mechanisms of action. We present the development of a novel polymeric thermosponge nanoparticle for efficient delivery of labile proteins using a solvent-free polymer thermo-expansion mechanism with clinical potential, capable of effectively delivering a range of therapeutic proteins in a sustained manner with no loss of bioactivity, with improved biological half-lives and efficacy in vivo. PMID:25333768

  3. Labile soil carbon inputs mediate the soil microbial community composition and plant residue decomposition rates

    SciTech Connect

    De Graaff, Marie-Anne; Classen, Aimee T; Castro Gonzalez, Hector F; Schadt, Christopher Warren

    2010-01-01

    Root carbon (C) inputs may regulate decomposition rates in soil, and in this study we ask: how do labile C inputs regulate decomposition of plant residues, and soil microbial communities? In a 14 d laboratory incubation, we added C compounds often found in root exudates in seven different concentrations (0, 0.7, 1.4, 3.6, 7.2, 14.4 and 21.7 mg C g{sup -1} soil) to soils amended with and without {sup 13}C-labeled plant residue. We measured CO{sub 2} respiration and shifts in relative fungal and bacterial rRNA gene copy numbers using quantitative polymerase chain reaction (qPCR). Increased labile C input enhanced total C respiration, but only addition of C at low concentrations (0.7 mg C g{sup -1}) stimulated plant residue decomposition (+2%). Intermediate concentrations (1.4, 3.6 mg C g{sup -1}) had no impact on plant residue decomposition, while greater concentrations of C (> 7.2 mg C g{sup -1}) reduced decomposition (-50%). Concurrently, high exudate concentrations (> 3.6 mg C g{sup -1}) increased fungal and bacterial gene copy numbers, whereas low exudate concentrations (< 3.6 mg C g{sup -1}) increased metabolic activity rather than gene copy numbers. These results underscore that labile soil C inputs can regulate decomposition of more recalcitrant soil C by controlling the activity and relative abundance of fungi and bacteria.

  4. The effect of acidification on the bioavailability and electrochemical lability of zinc in seawater

    NASA Astrophysics Data System (ADS)

    Kim, Ja-Myung; Baars, Oliver; Morel, François M. M.

    2016-11-01

    A poorly studied but potentially important consequence of the CO2-induced acidification of the surface ocean is a possible change in the bioavailability of trace metals, which play a critical role in the productivity and population dynamics of marine ecosystems. We report laboratory and field experiments designed to compare quantitatively the effects of acidification on the bioavailability of Zn, a metal essential to the growth of phytoplankton and on the extent of its complexation by model and natural ligands. We observed a good correspondence between the effects of pH on the rate of Zn uptake by a model diatom and the chemical lability of Zn measured by anodic stripping voltammetry (ASV). In model laboratory systems, the chemical lability and the bioavailability of Zn could either increase or decrease at low pH depending on the mix of complexing ligands. In a sample of coastal surface water, we observed similar increases in the ASV-labile and bioavailable Zn concentrations upon acidification, a result contrary to previous observations. These results, which can likely be generalized to other bioactive trace metals, mutatis mutandis, demonstrate the intricacy of the effects of ocean acidification on the chemistry and the ecology of surface seawater. This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.

  5. Evolution of phenotypic plasticity and environmental tolerance of a labile quantitative character in a fluctuating environment.

    PubMed

    Lande, R

    2014-05-01

    Quantitative genetic models of evolution of phenotypic plasticity are used to derive environmental tolerance curves for a population in a changing environment, providing a theoretical foundation for integrating physiological and community ecology with evolutionary genetics of plasticity and norms of reaction. Plasticity is modelled for a labile quantitative character undergoing continuous reversible development and selection in a fluctuating environment. If there is no cost of plasticity, a labile character evolves expected plasticity equalling the slope of the optimal phenotype as a function of the environment. This contrasts with previous theory for plasticity influenced by the environment at a critical stage of early development determining a constant adult phenotype on which selection acts, for which the expected plasticity is reduced by the environmental predictability over the discrete time lag between development and selection. With a cost of plasticity in a labile character, the expected plasticity depends on the cost and on the environmental variance and predictability averaged over the continuous developmental time lag. Environmental tolerance curves derived from this model confirm traditional assumptions in physiological ecology and provide new insights. Tolerance curve width increases with larger environmental variance, but can only evolve within a limited range. The strength of the trade-off between tolerance curve height and width depends on the cost of plasticity. Asymmetric tolerance curves caused by male sterility at high temperature are illustrated. A simple condition is given for a large transient increase in plasticity and tolerance curve width following a sudden change in average environment.

  6. Memory labilization in reconsolidation and extinction--evidence for a common plasticity system?

    PubMed

    Almeida-Corrêa, Suellen; Amaral, Olavo B

    2014-01-01

    Reconsolidation and extinction are two processes occurring upon memory retrieval that have received great attention in memory research over the last decade, partly due to their purported potential in the treatment of anxiety disorders. Due to their opposite behavioral effects, the two phenomena have usually been considered as separate entities, with few attempts to build a unified view of how both could be produced by similar mechanisms. Based on computational modeling, we have previously proposed that reconsolidation and extinction are behavioral outcomes of the same set of plasticity systems, albeit working at different synapses. One of these systems seems to be pharmacologically similar to the one involved in initial memory consolidation, and likely involves traditional Hebbian plasticity, while the second seems to be more involved with the labilization of existing memories and/or synaptic changes. In this article, we review the evidence for the existence of a plasticity system specifically involved in memory labilization, as well as its possible molecular requirements, anatomical substrates, synaptic mechanisms and physiological roles. Based on these data, we propose that the field of memory updating might ultimately benefit from a paradigm shift in which reconsolidation and extinction are viewed not as separate processes but as different instantiations of plasticity systems responsible for reinforcement and labilization of synaptic changes.

  7. Substrate lability and plant activity controls greenhouse gas release from Neotropical peatland

    NASA Astrophysics Data System (ADS)

    Sjogersten, Sofie; Hoyos, Jorge; Lomax, Barry; Turner, Ben; Wright, Emma

    2014-05-01

    Almost one third of global CO2 emissions resulting from land use change and substantial CH4 emissions originate from tropical peatlands. However, our understanding of the controls of CO2 and CH4 release from tropical peatlands are limited. The aim of this study was to investigate the role of peat lability and the activity of the vegetation on gas release using a combination of field and laboratory experiments. We demonstrated that peat lability constrained CH4 production to the surface peat under anaerobic conditions. The presence of plants shifted the C balance from a C source to a C sink with respect to CO2 while the activity of the root system strongly influenced CH4 emissions through its impact on soil O2 inputs. Both field and laboratory data suggest a coupling between the photosynthetic activity of the vegetation and the release of both CO2 and CH4 following the circadian rhythm of the dominant plant functional types. Forest clearance for agriculture resulted in elevated CH4 release, which we attribute in part to the cessation of root O2 inputs to the peat. We conclude that high emissions of CO2 and CH4 from forested tropical peatlands are likely driven by labile C inputs from the vegetation but that root O2 release may limit CH4 emissions.

  8. Lability of heavy metal species in aquatic humic substances characterized by ion exchange with cellulose phosphate.

    PubMed

    Rocha, J C; Toscano, I A; Burba, P

    1997-01-01

    Labile metal species in aquatic humic substances (HSs) were characterized by ion exchange on cellulose phosphate (CellPhos) by applying an optimized batch procedure. The HSs investigated were pre-extracted from humic-rich waters by ultrafiltration and a resin XAD 8 procedure. The HS-metal species studied were formed by complexation with Cd(II), Ni(II), Cu(II), Mn(II) and Pb(II) as a function of time and the ratio ions to HSs. The kinetics and reaction order of this exchange process were studied. At the beginning (<3 min), the labile metal fractions are separated relatively quickly. After 3 min, the separation of the metal ions proceeds with uniform half-lives of about 12-14 min, revealing rather slow first-order kinetics. The metal exchange between HSs and CellPhos exhibited the following order of metal lability with the studied HSs: Cu > Pb > Mn > Ni > Cd. The required metal determinations were carried out by atomic absorption spectrometry.

  9. Strategies to suppress hydrogen-consuming microorganisms affect macro and micro scale structure and microbiology of granular sludge.

    PubMed

    Abreu, A A; Alves, J I; Pereira, M A; Sousa, D Z; Alves, M M

    2011-08-01

    Treatment of anaerobic granules with heat and two chemical treatments, contacting with 2-bromoethanesulfonate (BES) and with BES + Chloroform, were applied to suppress hydrogen-consuming microorganisms. Three mesophilic expanded granular sludge bed (EGSB) reactors-R(Heat), R(BES), and R(BES + Chlo)--were inoculated with the treated sludges and fed with synthetic sugar-based wastewater (5 g(COD) L(-1), HRT 20-12 h). Morphological integrity of granules and bacterial communities were assessed by quantitative image analysis and 16S rRNA gene based techniques, respectively. Hydrogen production in R(Heat) was under 300 mL H(2) L(-1) day(-1), with a transient peak of 1,000 mL H(2) L(-1) day(-1) after decreasing HRT. In R(BES + Chlo) hydrogen production rate did not exceed 300 mL H(2) L(-1) day(-1) and there was granule fragmentation, release of free filaments from aggregates, and decrease of granule density. In R(BES), there was an initial period with unstable hydrogen production, but a pulse of BES triggered its production rate to 700 ± 200 mL H(2) L(-1) day(-1). This strategy did not affect granules structure significantly. Bacteria branching within Clostridiaceae and Ruminococcaceae were present in this sludge. This work demonstrates that, methods applied to suppress H(2)-consuming microorganisms can cause changes in the macro- and microstructure of granular sludge, which can be incompatible with the operation of high-rate reactors.

  10. Inherited variants affecting RNA editing may contribute to ovarian cancer susceptibility: results from a large-scale collaboration

    PubMed Central

    Permuth, Jennifer B.; Reid, Brett; Earp, Madalene; Chen, Y. Ann; Monteiro, Alvaro N.A.; Chen, Zhihua; Group, AOCS Study; Chenevix-Trench, Georgia; Fasching, Peter A.; Beckmann, Matthias W.; Lambrechts, Diether; Vanderstichele, Adriaan; Niewenhuyse, Els Van; Vergote, Ignace; Rossing, Mary Anne; Doherty, Jennifer Anne; Chang-Claude, Jenny; Moysich, Kirsten; Odunsi, Kunle; Goodman, Marc T.; Shvetsov, Yurii B.; Wilkens, Lynne R.; Thompson, Pamela J.; Dörk, Thilo; Bogdanova, Natalia; Butzow, Ralf; Nevanlinna, Heli; Pelttari, Liisa; Leminen, Arto; Modugno, Francesmary; Edwards, Robert P.; Ness, Roberta B.; Kelley, Joseph; Heitz, Florian; Karlan, Beth; Lester, Jenny; Kjaer, Susanne K.; Jensen, Allan; Giles, Graham; Hildebrandt, Michelle; Liang, Dong; Lu, Karen H.; Wu, Xifeng; Levine, Douglas A.; Bisogna, Maria; Berchuck, Andrew; Cramer, Daniel W.; Terry, Kathryn L.; Tworoger, Shelley S.; Poole, Elizabeth M.; Bandera, Elisa V.; Fridley, Brooke; Cunningham, Julie; Winham, Stacey J.; Olson, Sara H.; Orlow, Irene; Bjorge, Line; Kiemeney, Lambertus A.; Massuger, Leon; Pejovic, Tanja; Moffitt, Melissa; Le, Nhu; Cook, Linda S.; Brooks-Wilson, Angela; Kelemen, Linda E.; Gronwald, Jacek; Lubinski, Jan; Wentzensen, Nicolas; Brinton, Louise A.; Lissowska, Jolanta; Yang, Hanna; Hogdall, Estrid; Hogdall, Claus; Lundvall, Lene; Pharoah, Paul D.P.; Song, Honglin; Campbell, Ian; Eccles, Diana; McNeish, Iain; Whittemore, Alice; McGuire, Valerie; Sieh, Weiva; Rothstein, Joseph; Phelan, Catherine M.; Risch, Harvey; Narod, Steven; McLaughlin, John; Anton-Culver, Hoda; Ziogas, Argyrios; Menon, Usha; Gayther, Simon; Ramus, Susan J.; Gentry-Maharaj, Aleksandra; Pearce, Celeste Leigh; Wu, Anna H.; Kupryjanczyk, Jolanta; Dansonka-Mieszkowska, Agnieszka; Schildkraut, Joellen M.; Cheng, Jin Q.; Goode, Ellen L.; Sellers, Thomas A.

    2016-01-01

    RNA editing in mammals is a form of post-transcriptional modification in which adenosine is converted to inosine by the adenosine deaminases acting on RNA (ADAR) family of enzymes. Based on evidence of altered ADAR expression in epithelial ovarian cancers (EOC), we hypothesized that single nucleotide polymorphisms (SNPs) in ADAR genes modify EOC susceptibility, potentially by altering ovarian tissue gene expression. Using directly genotyped and imputed data from 10,891 invasive EOC cases and 21,693 controls, we evaluated the associations of 5,303 SNPs in ADAD1, ADAR, ADAR2, ADAR3, and SND1. Unconditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI), with adjustment for European ancestry. We conducted gene-level analyses using the Admixture Maximum Likelihood (AML) test and the Sequence-Kernel Association test for common and rare variants (SKAT-CR). Association analysis revealed top risk-associated SNP rs77027562 (OR (95% CI)= 1.39 (1.17-1.64), P=1.0×10−4) in ADAR3 and rs185455523 in SND1 (OR (95% CI)= 0.68 (0.56-0.83), P=2.0×10−4). When restricting to serous histology (n=6,500), the magnitude of association strengthened for rs185455523 (OR=0.60, P=1.0×10−4). Gene-level analyses revealed that variation in ADAR was associated (P<0.05) with EOC susceptibility, with PAML=0.022 and PSKAT-CR=0.020. Expression quantitative trait locus analysis in EOC tissue revealed significant associations (P<0.05) with ADAR expression for several SNPs in ADAR, including rs1127313 (G/A), a SNP in the 3′ untranslated region. In summary, germline variation involving RNA editing genes may influence EOC susceptibility, warranting further investigation of inherited and acquired alterations affecting RNA editing. PMID:27911851

  11. Inherited variants affecting RNA editing may contribute to ovarian cancer susceptibility: results from a large-scale collaboration.

    PubMed

    Permuth, Jennifer B; Reid, Brett; Earp, Madalene; Chen, Y Ann; Monteiro, Alvaro N A; Chen, Zhihua; Chenevix-Trench, Georgia; Fasching, Peter A; Beckmann, Matthias W; Lambrechts, Diether; Vanderstichele, Adriaan; Van Niewenhuyse, Els; Vergote, Ignace; Rossing, Mary Anne; Doherty, Jennifer Anne; Chang-Claude, Jenny; Moysich, Kirsten; Odunsi, Kunle; Goodman, Marc T; Shvetsov, Yurii B; Wilkens, Lynne R; Thompson, Pamela J; Dörk, Thilo; Bogdanova, Natalia; Butzow, Ralf; Nevanlinna, Heli; Pelttari, Liisa; Leminen, Arto; Modugno, Francesmary; Edwards, Robert P; Ness, Roberta B; Kelley, Joseph; Heitz, Florian; Karlan, Beth; Lester, Jenny; Kjaer, Susanne K; Jensen, Allan; Giles, Graham; Hildebrandt, Michelle; Liang, Dong; Lu, Karen H; Wu, Xifeng; Levine, Douglas A; Bisogna, Maria; Berchuck, Andrew; Cramer, Daniel W; Terry, Kathryn L; Tworoger, Shelley S; Poole, Elizabeth M; Bandera, Elisa V; Fridley, Brooke; Cunningham, Julie; Winham, Stacey J; Olson, Sara H; Orlow, Irene; Bjorge, Line; Kiemeney, Lambertus A; Massuger, Leon; Pejovic, Tanja; Moffitt, Melissa; Le, Nhu; Cook, Linda S; Brooks-Wilson, Angela; Kelemen, Linda E; Gronwald, Jacek; Lubinski, Jan; Wentzensen, Nicolas; Brinton, Louise A; Lissowska, Jolanta; Yang, Hanna; Hogdall, Estrid; Hogdall, Claus; Lundvall, Lene; Pharoah, Paul D P; Song, Honglin; Campbell, Ian; Eccles, Diana; McNeish, Iain; Whittemore, Alice; McGuire, Valerie; Sieh, Weiva; Rothstein, Joseph; Phelan, Catherine M; Risch, Harvey; Narod, Steven; McLaughlin, John; Anton-Culver, Hoda; Ziogas, Argyrios; Menon, Usha; Gayther, Simon; Ramus, Susan J; Gentry-Maharaj, Aleksandra; Pearce, Celeste Leigh; Wu, Anna H; Kupryjanczyk, Jolanta; Dansonka-Mieszkowska, Agnieszka; Schildkraut, Joellen M; Cheng, Jin Q; Goode, Ellen L; Sellers, Thomas A

    2016-11-08

    RNA editing in mammals is a form of post-transcriptional modification in which adenosine is converted to inosine by the adenosine deaminases acting on RNA (ADAR) family of enzymes. Based on evidence of altered ADAR expression in epithelial ovarian cancers (EOC), we hypothesized that single nucleotide polymorphisms (SNPs) in ADAR genes modify EOC susceptibility, potentially by altering ovarian tissue gene expression. Using directly genotyped and imputed data from 10,891 invasive EOC cases and 21,693 controls, we evaluated the associations of 5,303 SNPs in ADAD1, ADAR, ADAR2, ADAR3, and SND1. Unconditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI), with adjustment for European ancestry. We conducted gene-level analyses using the Admixture Maximum Likelihood (AML) test and the Sequence-Kernel Association test for common and rare variants (SKAT-CR). Association analysis revealed top risk-associated SNP rs77027562 (OR (95% CI)= 1.39 (1.17-1.64), P=1.0x10-4) in ADAR3 and rs185455523 in SND1 (OR (95% CI)= 0.68 (0.56-0.83), P=2.0x10-4). When restricting to serous histology (n=6,500), the magnitude of association strengthened for rs185455523 (OR=0.60, P=1.0x10-4). Gene-level analyses revealed that variation in ADAR was associated (P<0.05) with EOC susceptibility, with PAML=0.022 and PSKAT-CR=0.020. Expression quantitative trait locus analysis in EOC tissue revealed significant associations (P<0.05) with ADAR expression for several SNPs in ADAR, including rs1127313 (G/A), a SNP in the 3' untranslated region. In summary, germline variation involving RNA editing genes may influence EOC susceptibility, warranting further investigation of inherited and acquired alterations affecting RNA editing.

  12. Predicting the solubility and lability of Zn, Cd, and Pb in soils from a minespoil-contaminated catchment by stable isotopic exchange

    NASA Astrophysics Data System (ADS)

    Marzouk, E. R.; Chenery, S. R.; Young, S. D.

    2013-12-01

    The Rookhope catchment of Weardale, England, has a diverse legacy of contaminated soils due to extensive lead mining activity over four centuries. We measured the isotopically exchangeable content of Pb, Cd and Zn (E-values) in a large representative subset of the catchment soils (n = 246) using stable isotope dilution. All three metals displayed a wide range of %E-values (c. 1-100%) but relative lability followed the sequence Cd > Pb > Zn. A refinement of the stable isotope dilution approach also enabled detection of non-reactive metal contained within suspended sub-micron (<0.22 μm) colloidal particles (SCP-metal). For most soils, the presence of non-labile SCP-metal caused only minor over-estimation of E-values (<2%) but the effect was greater for soils with particularly large humus or carbonate contents. Approximately 80%, 53% and 66% of the variability in Zn, Cd and Pb %E-values (respectively) could be explained by pH, loss on ignition and total metal content. E-values were affected by the presence of ore minerals at high metal contents leading to an inconsistent trend in the relationship between %E-value and soil metal concentration. Metal solubility, in the soil suspensions used to measure E-values, was predicted using the WHAM geochemical speciation model (versions VI and VII). The use of total and isotopically exchangeable metal as alternative input variables was compared; the latter provided significantly better predictions of solubility, especially in the case of Zn. Lead solubility was less well predicted by either version of WHAM, with over-prediction at low pH and under-prediction at high soil pH values. Quantify the isotopically exchangeable fractions of Zn, Cd and Pb (E-values), and assess their local and regional variability, using multi-element stable isotope dilution, in a diverse range of soil ecosystems within the catchment of an old Pb/Zn mining area. Assess the controlling influences of soil properties on metal lability and develop

  13. Assessing the Selectivity of Extractant Solutions for Recovering Labile Arsenic Associated with Iron (Hydr)oxides and Sulfides in Sediments

    EPA Science Inventory

    Sequential extractions can provide analytical constraints on the identification of mineral phases that control arsenic speciation in sediments. Model solids were used in this study to evaluate different solutions designed to extract arsenic from relatively labile solid phases. ...

  14. Detection of heat-labile enterotoxin-like activity in stools of patients with cholera and Escherichia coli diarrhea.

    PubMed Central

    Echeverria, P; Verheart, L; Ulyanco, C V; Santiago, L T

    1978-01-01

    The Y1 adrenal cell tissue culture assay was used to detect heat-labile enterotoxin-like activity in the stools of 14 of 74 patients with diarrhea. A positive effect of the stool on the adrenal cells was heat-labile and neutralized by cholera antitoxin. Enterotoxin-like activity was detected in the stools of 10 of 30 patients with cholera and in those of 2 of 4 from whom heat-labile Escherichia coli were isolated. None of the stools from nine individuals with Vibrio parahaemolyticus, Salmonella, or Shigella infections were positive. Two of 31 individuals from whom no pathogens were isolated had detectable toxin-like activity in their stools. The Y1 adrenal cell assay provides a rapid method of diagnosing heat-labile enterotoxigenic diarrhea and could be an adjunct in epidemiological studies of gastroenteritis. PMID:342414

  15. Presentation and validation of the multiple sclerosis depression rating scale: a test specifically devised to investigate affective disorders in multiple sclerosis patients.

    PubMed

    Quaranta, Davide; Marra, Camillo; Zinno, Massimiliano; Patanella, Agata Katia; Messina, Maria Josè; Piccininni, Chiara; Batocchi, Anna Paola; Gainotti, Guido

    2012-01-01

    Accurate diagnosis of depression in patients affected by MS is important, as it may be a cause of reduced quality of life and increased suicide risk. We present a new scale, the Multiple Sclerosis Depression Rating Scale (MSDRS), and assess its diagnostic accuracy in comparison to the Beck Depression Inventory (BDI). A total of 94 MS participants were classified as non-depressed (N = 44) or affected by mood disorder associated to MS with depressive manifestations (MSD-MDDM; N = 37) or with a major depression-like episode (MSD-MDL; N = 13). Each participant underwent a psychiatric interview, MSDRS, and BDI; diagnostic accuracy was evaluated using area under the ROC curve (AROC). The diagnostic accuracy of MSDRS and BDI was comparable when diagnosing both MSD-MDDM and MSD-MDL (AROC respectively 0.8998 and 0.8659); the MSDRS showed higher accuracy for the diagnosis of MSD-MDL (AROC respectively 0.9278 and 0.8314; p = .038). The MSDRS may be a reliable tool for the diagnosis of depression in MS.

  16. How does the connectivity of open-framework conglomerates within multi-scale hierarchical fluvial architecture affect oil sweep efficiency in waterflooding?

    NASA Astrophysics Data System (ADS)

    Dominic, D. F.; Gershenzon, N. I.; Soltanian, M. R.; Ritzi, R. W., Jr.; Keefer, D. A.; Shaffer, E.; Storsved, B.

    2014-12-01

    We studied the effects on oil sweep efficiency of the proportion, hierarchical organization, and connectivity of high-permeability open-framework conglomerate (OFC) cross-sets within the multi-scale stratal architecture found in fluvial deposits. Utilizing numerical simulations and the RVA/Paraview open-source visualization package, we analyzed oil production rate, water breakthrough time, and spatial and temporal distribution of residual oil saturation. The effective permeability of the reservoir exhibits large-scale anisotropy created by the organization of OFC cross-sets within unit bars, and the organization of unit bars within compound bars. As a result, oil sweep efficiency critically depends on the direction of the pressure gradient. When pressure gradient is oriented normal to paleoflow direction, the total oil production and the water breakthrough time are larger, and remaining oil saturation is smaller. This result is found regardless of the proportion or connectivity of the OFC cross-sets, within the ranges examined. Contrary to expectations, the total amount of trapped oil due to the effect of capillary trapping does not depend on the pressure gradient within the examined range. Hence the pressure difference between production and injection wells does not affect sweep efficiency, although the spatial distribution of oil remaining in the reservoir depends on this value. Whether or not clusters of connected OFC span the domain does not affect sweep efficiency, only the absolute rate of oil production. The RVA/Paraview application allowed us to visualize and examine these non-intuitive results.

  17. Molecular insights into the microbial formation of marine dissolved organic matter: recalcitrant or labile?

    NASA Astrophysics Data System (ADS)

    Koch, B. P.; Kattner, G.; Witt, M.; Passow, U.

    2014-08-01

    The degradation of marine dissolved organic matter (DOM) is an important control variable in the global carbon cycle. For our understanding of the kinetics of organic matter cycling in the ocean, it is crucial to achieve a mechanistic and molecular understanding of its transformation processes. A long-term microbial experiment was performed to follow the production of non-labile DOM by marine bacteria. Two different glucose concentrations and dissolved algal exudates were used as substrates. We monitored the bacterial abundance, concentrations of dissolved and particulate organic carbon (DOC, POC), nutrients, amino acids and transparent exopolymer particles (TEP) for 2 years. The molecular characterization of extracted DOM was performed by ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) after 70 days and after ∼2 years of incubation. Although glucose quickly degraded, a non-labile DOC background (5-9% of the initial DOC) was generated in the glucose incubations. Only 20% of the organic carbon from the algal exudate degraded within the 2 years of incubation. The degradation rates for the non-labile DOC background in the different treatments varied between 1 and 11 μmol DOC L-1 year-1. Transparent exopolymer particles, which are released by microorganisms, were produced during glucose degradation but decreased back to half of the maximum concentration within less than 3 weeks (degradation rate: 25 μg xanthan gum equivalents L-1 d-1) and were below detection in all treatments after 2 years. Additional glucose was added after 2 years to test whether labile substrate can promote the degradation of background DOC (co-metabolism; priming effect). A priming effect was not observed but the glucose addition led to a slight increase of background DOC. The molecular analysis demonstrated that DOM generated during glucose degradation differed appreciably from DOM transformed during the degradation of the algal exudates. Our

  18. Reduced contribution of thermally-labile sugar lesions to DNA double-strand break formation after exposure to neutrons.

    PubMed

    Singh, Satyendra K; Wu, Wenqi; Stuschke, Martin; Bockisch, Andreas; Iliakis, George

    2012-12-01

    In cells exposed to ionizing radiation, double-strand breaks (DSBs) form within clustered damage sites from lesions disrupting the DNA sugar-phosphate backbone. It is commonly assumed that DSBs form promptly and are immediately detected and processed by the cellular DNA damage response apparatus. However, DSBs also form by delayed chemical conversion of thermally-labile sugar lesions (TLSL) to breaks. We recently reported that conversion of thermally-labile sugar lesions to breaks occurs in cells maintained at physiological temperatures. Here, we investigate the influence of radiation quality on the formation of thermally-labile sugar lesions dependent DSBs. We show that, although the yields of total DSBs are very similar after exposure to neutrons and X rays, the yields of thermally-labile sugar lesions dependent DSBs from neutrons are decreased in comparison to that from X rays. Thus, the yields of prompt DSBs for neutrons are greater than for X rays. Notably, after neutron irradiation the decreased yield of thermally-labile sugar lesion dependent DSBs is strongly cell line dependent, likely reflecting subtle differences in DNA organization. We propose that the higher ionization density of neutrons generates with higher probability prompt DSBs within ionization clusters and renders the ensuing chemical evolution of thermally-labile sugar lesions inconsequential to DNA integrity. Modification of thermally-labile sugar lesion evolution may define novel radiation protection strategies aiming at decreasing DSB formation by chemically preserving thermally-labile sugar lesions until other DSB contributing lesions within the clustered damage site are removed by non-DSB repair pathways.

  19. Interactive effects of water supply and defoliation on photosynthesis, plant water status and growth of Eucalyptus globulus Labill.

    PubMed

    Quentin, A G; O'Grady, A P; Beadle, C L; Mohammed, C; Pinkard, E A

    2012-08-01

    Increased climatic variability, including extended periods of drought stress, may compromise on the health of forest ecosystems. The effects of defoliating pests on plantations may also impact on forest productivity. Interactions between climate signals and pest activity are poorly understood. In this study, we examined the combined effects of reduced water availability and defoliation on maximum photosynthetic rate (A(sat)), stomatal conductance (g(s)), plant water status and growth of Eucalyptus globulus Labill. Field-grown plants were subjected to two water-availability regimes, rain-fed (W-) and irrigated (W+). In the summer of the second year of growth, leaves from 75% of crown length removed from trees in both watering treatments and physiological responses within the canopies were examined. We hypothesized that defoliation would result in improved plant water status providing a mechanistic insight into leaf- and canopy-scale gas-exchange responses. Defoliated trees in the W+ treatment exhibited higher A(sat) and g(s) compared with non-defoliated trees, but these responses were not observed in the W- treatment. In contrast, at the whole-plant scale, maximum rates of transpiration (E(max)) and canopy conductance (G(Cmax)) and soil-to-leaf hydraulic conductance (K(P)) increased in both treatments following defoliation. As a result, plant water status was unaffected by defoliation and trees in the defoliated treatments exhibited homeostasis in this respect. Whole-plant soil-to-leaf hydraulic conductance was strongly correlated with leaf scale g(s) and A(sat) following the defoliation, providing a mechanistic insight into compensatory up-regulation of photosynthesis. Above-ground height and diameter growth were unaffected by defoliation in both water availability treatments, suggesting that plants use a range of responses to compensate for the impacts of defoliation.

  20. Repair of radiation-induced heat-labile sites is independent of DNA-PKcs, XRCC1 or PARP

    SciTech Connect

    Stenerlöw, Bo; Karlsson, Karin H.; Radulescu, Irina; Rydberg, Bjorn; Stenerlow, Bo

    2008-04-29

    Ionizing radiation induces a variety of different DNA lesions: in addition to the most critical DNA damage, the DSB, numerous base alterations, SSBs and other modifications of the DNA double-helix are formed. When several non-DSB lesions are clustered within a short distance along DNA, or close to a DSB, they may interfere with the repair of DSBs and affect the measurement of DSB induction and repair. We have previously shown that a substantial fraction of DSBs measured by pulsed-field gel electrophoresis (PFGE) are in fact due to heat-labile sites (HLS) within clustered lesions, thus reflecting an artifact of preparation of genomic DNA at elevated temperature. To further characterize the influence of HLS on DSB induction and repair, four human cell lines (GM5758, GM7166, M059K, U-1810) with apparently normal DSB rejoining were tested for bi-phasic rejoining after gamma irradiation. When heat-released DSBs were excluded from the measurements the fraction of fast rejoining decreased to less than 50% of the total. However, neither the half-times of the fast (t{sub 1/2} = 7-8 min) or slow (t{sub 1/2} = 2.5 h) DSB rejoining were changed significantly. At t=0 the heat-released DSBs accounted for almost 40% of the DSBs, corresponding to 10 extra DSB/cell/Gy in the initial DSB yield. These heat-released DSBs were repaired within 60-90 min in all tested cells, including M059K cells treated with wortmannin or DNA-PKcs defect M059J cells. Furthermore, cells lacking XRCC1 or Poly(ADP-ribose) polymerase-1 (PARP-1) rejoined both total DSBs and heat-released DSBs similar to normal cells. In summary, the presence of heat-labile sites have a substantial impact on DSB induction yields and DSB rejoining rates measured by pulsed-field gel electrophoresis, and HLS repair is independent of DNA-PKcs, XRCC1 and PARP.

  1. Self-Compassion Scale (SCS): Psychometric Properties of The French Translation and Its Relations with Psychological Well-Being, Affect and Depression

    PubMed Central

    Kotsou, Ilios; Leys, Christophe

    2016-01-01

    Over the past few years, the topic of self-compassion has attracted increasing attention from both scientific and clinical fields. The Self-Compassion Scale (SCS) was created to specifically capture this way of being kind and understanding towards oneself in moments of turmoil. In this article, we present a French adaptation of the SCS. We first explore the psychometric properties of this adaptation and then investigate its relation to psychological well-being. As in the original version of the SCS, the French adaptation has a strong 6-factor structure but a weaker hierarchical second order structure. However the bi-factor model yields a good omega index suggesting the relevance of a single score accounting for self-compassion. Moreover, there was a relation between the SCS and classical outcomes such as a positive relation with psychological well-being and negative relation with depressive symptoms. We then hypothesized that self-compassion would have a moderating role on the relation between affect and depression. This hypothesis was confirmed: expressing negative affect is correlated with depressive symptoms; however, being kind with oneself lowers depressive symptoms even when expressing negative affect. In conclusion, this research presents a valid self-compassion measure for French-speaking researchers and clinicians and outlines the need for further research on the concept of self-compassion. PMID:27078886

  2. Self-Compassion Scale (SCS): Psychometric Properties of The French Translation and Its Relations with Psychological Well-Being, Affect and Depression.

    PubMed

    Kotsou, Ilios; Leys, Christophe

    2016-01-01

    Over the past few years, the topic of self-compassion has attracted increasing attention from both scientific and clinical fields. The Self-Compassion Scale (SCS) was created to specifically capture this way of being kind and understanding towards oneself in moments of turmoil. In this article, we present a French adaptation of the SCS. We first explore the psychometric properties of this adaptation and then investigate its relation to psychological well-being. As in the original version of the SCS, the French adaptation has a strong 6-factor structure but a weaker hierarchical second order structure. However the bi-factor model yields a good omega index suggesting the relevance of a single score accounting for self-compassion. Moreover, there was a relation between the SCS and classical outcomes such as a positive relation with psychological well-being and negative relation with depressive symptoms. We then hypothesized that self-compassion would have a moderating role on the relation between affect and depression. This hypothesis was confirmed: expressing negative affect is correlated with depressive symptoms; however, being kind with oneself lowers depressive symptoms even when expressing negative affect. In conclusion, this research presents a valid self-compassion measure for French-speaking researchers and clinicians and outlines the need for further research on the concept of self-compassion.

  3. Total and Labile Phosphorus Concentrations as Influenced by Riparian Buffer Soil Properties.

    PubMed

    Young, Eric O; Ross, Donald S

    2016-01-01

    Riparian buffers can act as a phosphorus (P) source under active stream bank erosion. Using soil and landscape variables (soil series, drainage class, organic matter, and pH) to index P concentrations could improve P loss risk tools for buffers. The objectives of this study were (i) to determine if soil properties could predict total and labile P concentrations within a 10-ha riparian buffer and (ii) to quantify the degree of spatial dependence of P and related properties. Soil samples were taken in 15-cm increments to a depth of 60 cm using a grid ( = 71) from an established riparian buffer along the Rock River in Vermont. Total soil P (TP), plant-available P determined by Modified Morgan extraction (MM-P), pH, soil organic matter (SOM), soil texture, and select cations were measured. We found that TP (152-1536 mg P kg) and MM-P (0.4-14.6 mg kg) ranged widely, with distinct differences between soil series. Mean TP and MM-P were greater in alluvial and glaciolacustrine soils compared with glacial till. Across all samples, MM-P was weakly related to soil properties; however, total labile P (orthophosphate + organic P measured by ICP) and unreactive labile P (ICP-P - colorimetric-P) could both be predicted by SOM ( = 0.59 and 0.73, respectively). Strong spatial dependence was found for P and related properties as revealed by geospatial analyses. Results show that P availability in the buffer was strongly related to soil genesis and support site-specific approaches for P loss risk evaluation in buffers.

  4. Interactions between recalcitrant and labile organic carbon in streams - Can stream biofilms mediate a priming effect?

    NASA Astrophysics Data System (ADS)

    Bengtsson, M. M.; Wagner, K.; Herberg, E. R.; Burns, N. R.; Wanek, W.; Battin, T. J.

    2012-04-01

    Inland waters - such as streams, rivers and lakes - are increasingly recognized as important components in the global carbon cycle. Dissolved organic carbon (DOC) in these systems is diverse in structure, origin and reactivity, and a fraction of it is regarded as recalcitrant to microbial degradation. In soils, degradation of recalcitrant carbon is often controlled by the availability of labile carbon sources. This is linked to the priming effect (PE). Mounting evidence suggests that PE is also important in aquatic ecosystems but there are so far very few studies addressing this topic. Biofilms are vital components of aquatic ecosystems. In stream biofilms, heterotrophic bacteria and algae coexist in close proximity, exposing the bacteria to both recalcitrant DOC of terrestrial origin and labile organic carbon from the algae. We hypothesize that this makes stream biofilms hotspots for PE. We used plug-flow bioreactors inoculated with natural stream biofilm bacterial communities to test the potential of a priming effect in aquatic ecosystems. The bioreactors were amended with an isotope-labeled plant extract serving as a model of recalcitrant DOC in streams. Labile carbon sources, in the form of glucose and an algal extract were added to induce PE. Nitrate and phosphate were also added to assess the role of these inorganic nutrients on carbon uptake. Microbial uptake of the different carbon sources was monitored by measuring the concentrations and isotopic ratios of respired CO2, biomass and DOC. Our results suggest that the priming effect plays a role in stream carbon cycling and that it is potentially an important process in other aquatic ecosystems.

  5. Enantiomeric Excesses of Acid Labile Amino Acid Precursors of the Murchison Meteorite

    NASA Technical Reports Server (NTRS)

    Pizzarello, Sandra

    1998-01-01

    Amino acids present in carbonaceous chondrite are extracted in water in part as free compounds and in approximately equal part as acid labile precursors. On the assumption that they would be free of contamination, the precursors of two Murchison amino acids that have terrestrial occurrence, alanine and glutamic acid, have been targeted for analysis of their enantiomeric ratios. Pyroglutamic acid, the precursor of glutamic acid, was found with an L-enantiomeric excess comparable to that of the free acid, while alanine's precursor, N-acetyl alanine, appears approximately racemic. Also alpha-imino propioacetic acid, a proposed end product of alanine synthesis in the meteorite, was analyzed and found racemic.

  6. Nature of chiral-induced equilibrium shifts in racemic labile lanthanide complexes

    SciTech Connect

    Wu, Shuguang; Hilmes, G.L.; Riehl, J.P. )

    1989-03-23

    An analysis of the chiral-induced equilibrium shift of racemic D{sub 3} tris-terdendate complexes of lanthanides with 2,6-pyridinedicarboxylate is presented in terms of the associated/dissociated models of Schipper. Results are presented which indicate that the so-called Pfeiffer effect in these lanthanide complexes is best described by the dissociated model, as was determined for similar labile transition-metal complexes. The nature of the chiral discriminatory interaction is shown to be largely electrostatic by measurements in mixed solvents of varying dielectric constant.

  7. Experimental Observation of the Nature of Weak Chemical Bonds in Labile Compounds.

    PubMed

    Hashizume, Daisuke

    2017-02-15

    Accurate single-crystal X-ray diffraction data afford a total electron density distribution for crystalline materials by employing an aspherical atomic model with comparable accuracy to that of theoretical calculations. Chemical bonds and intermolecular interactions in the crystalline state are characterized based on the electron density distribution of valence electrons, as well as structural parameters. Herein, the bonding nature of weak chemical bonds in labile compounds, such as hypervalent bonds and delocalized π-bonds, is explored on the basis of electronic structures derived from experimental electron density distribution analyses. In addition, the visualization of a radicalic orbital distribution on an sp(2) -hydridized carbon atom is demonstrated.

  8. Essential oil composition of the fruits of Periploca laevigata Aiton subsp. angustifolia (Labill.) Markgraf (Apocynaceae - Periplocoideae).

    PubMed

    Zito, Pietro; Sajeva, Maurizio; Bruno, Maurizio; Maggio, Antonella; Rosselli, Sergio; Senatore, Felice; Formisano, Carmen

    2011-08-01

    The essential oil of the fruits of Periploca laevigata Aiton subsp. angustifolia (Labill.) Markgraf (Apocynaceae) from Lampedusa Island was obtained by hydrodistillation and its composition was analysed. The analyses allowed the identification and quantification of 64 volatile compounds belonging to different classes. The most abundant compounds were nonacosane, heptacosane, hentriacontane and δ-cadinene. Among the volatile compounds identified in the fruits of P. laevigata subsp. angustifolia, 31 are present in other taxa of Apocynaceae, 19 have antimicrobial activity and four are pheromones for the butterfly Danaus chrysippus. The possible ecological role of the volatile compounds found is briefly discussed.

  9. Mechanism-based design of labile precursors for chromium(I) chemistry

    SciTech Connect

    Akturk, Eser S.; Yap, Glenn P. A.; Theopold, Klaus H.

    2015-08-27

    Here, we report that dinitrogen complexes of the type TpR,RCr–N2–CrTpR,R are not the most labile precursors for Cr(I) chemistry, as they are sterically protected from obligatory associative ligand substitution. A mononuclear alkyne complex – TptBu,MeCr(η2-C2(SiMe3)2) – proved to be much more reactive.

  10. Estimating environmental conditions affecting protozoal pathogen removal in surface water wetland systems using a multi-scale, model-based approach.

    PubMed

    Daniels, Miles E; Hogan, Jennifer; Smith, Woutrina A; Oates, Stori C; Miller, Melissa A; Hardin, Dane; Shapiro, Karen; Los Huertos, Marc; Conrad, Patricia A; Dominik, Clare; Watson, Fred G R

    2014-09-15

    Cryptosporidium parvum, Giardia lamblia, and Toxoplasma gondii are waterborne protozoal pathogens distributed worldwide and empirical evidence suggests that wetlands reduce the concentrations of these pathogens under certain environmental conditions. The goal of this study was to evaluate how protozoal removal in surface water is affected by the water temperature, turbidity, salinity, and vegetation cover of wetlands in the Monterey Bay region of California. To examine how protozoal removal was affected by these environmental factors, we conducted observational experiments at three primary spatial scales: settling columns, recirculating wetland mesocosm tanks, and an experimental research wetland (Molera Wetland). Simultaneously, we developed a protozoal transport model for surface water to simulate the settling columns, the mesocosm tanks, and the Molera Wetland. With a high degree of uncertainty expected in the model predictions and field observations, we developed the model within a Bayesian statistical framework. We found protozoal removal increased when water flowed through vegetation, and with higher levels of turbidity, salinity, and temperature. Protozoal removal in surface water was maximized (~0.1 hour(-1)) when flowing through emergent vegetation at 2% cover, and with a vegetation contact time of ~30 minutes compared to the effects of temperature, salinity, and turbidity. Our studies revealed that an increase in vegetated wetland area, with water moving through vegetation, would likely improve regional water quality through the reduction of fecal protozoal pathogen loads.

  11. Factors affecting the quality of life of patients after gastrectomy as assessed using the newly developed PGSAS-45 scale: A nationwide multi-institutional study

    PubMed Central

    Nakada, Koji; Takahashi, Masazumi; Ikeda, Masami; Kinami, Shinichi; Yoshida, Masashi; Uenosono, Yoshikazu; Kawashima, Yoshiyuki; Nakao, Sayumi; Oshio, Atsushi; Suzukamo, Yoshimi; Terashima, Masanori; Kodera, Yasuhiro

    2016-01-01

    AIM To identify certain clinical factors other than the type of gastrectomy which affect the postoperative quality of life (QOL) of patients after gastrectomy. METHODS The postgastrectomy syndrome assessment scale (PGSAS)-45 was designed to assess the severity of symptoms, the living status and the QOL of gastrectomized patients. It consists of 45 items, of which 22 are original items while 23 were retrieved from the SF-8 and Gastrointestinal Symptoms Rating Scale questionnaires with permission. A nationwide surveillance study to validate PGSAS was conducted and 2368 gastric cancer patients who underwent various types of gastrectomy at 52 medical institutions were enrolled. Of these, 1777 patients who underwent total gastrectomy (TG) reconstructed with Roux-Y (n = 393), distal gastrectomy (DG) reconstructed with Billroth-I (n = 909), or DG reconstructed with Roux-Y (n = 475) were evaluated in the current study. The influence of the type of gastrectomy and other clinical factors such as age, sex, duration after surgery, the symptom severity, the degree of weight loss, dietary intake, and the ability for working on the postoperative QOL (i.e., dissatisfaction for daily life subscale, physical component summary and mental component summary of the SF-8) were examined by multiple regression analysis (MRA). In addition, importance of various symptoms such as esophageal reflux, abdominal pain, meal-related distress, indigestion, diarrhea, constipation and dumping on the postoperative living status and QOL were also appraised by MRA. RESULTS The postoperative QOL were significantly deteriorated in patients who underwent TG compared to those after DG. However, the extent of gastrectomy was not an influential factor on patients’ QOL when adjusted by the MRA. Among various clinical factors, the symptom severity, ability for working, and necessity for additional meals were the most influential factors to the postoperative QOL. As for the individual symptoms, meal

  12. Rhizosphere Environment and Labile Phosphorus Release from Organic Waste-Amended Soils.

    NASA Astrophysics Data System (ADS)

    Dao, Thanh H.

    2015-04-01

    Crop residues and biofertilizers are primary sources of nutrients for organic crop production. However, soils treated with large amounts of nutrient-enriched manure have elevated phosphorus (P) levels in regions of intensive animal agriculture. Surpluses occurred in these amended soils, resulting in large pools of exchangeable inorganic P (Pi) and enzyme-labile organic P (Po) that averaging 30.9 and 68.2 mg kg-1, respectively. Organic acids produced during crop residue decomposition can promote the complexation of counter-ions and decouple and release unbound Pi from metal and alkali metal phosphates. Animal manure and cover crop residues also contain large amounts of soluble organic matter, and likely generate similar ligands. However, a high degree of heterogeneity in P spatial distribution in such amended fields, arising from variances in substrate physical forms ranging from slurries to dried solids, composition, and diverse application methods and equipment. Distinct clusters of Pi and Po were observed, where accumulation of the latter forms was associated with high soil microbial biomass C and reduced phosphomonoesterases' activity. Accurate estimates of plant requirements and lability of soil P pools, and real-time plant and soil P sensing systems are critical considerations to optimally manage manure-derived nutrients in crop production systems. An in situ X-ray fluorescence-based approach to sensing canopy and soil XRFS-P was developed to improve the yield-soil P relationship for optimal nutrient recommendations in addition to allowing in-the-field verification of foliar P status.

  13. Effects of lability of metal complex on free ion measurement using DMT.

    PubMed

    Weng, Liping; Van Riemsdijk, Willem H; Temminghoff, Erwin J M

    2010-04-01

    Very low concentrations of free metal ion in natural samples can be measured using the Donnan membrane technique (DMT) based on ion transport kinetics. In this paper, the possible effects of slow dissociation of metal complexes on the interpretation of kinetic DMT are investigated both theoretically and experimentally. The expressions of the lability parameter, Lgrangian , were derived for DMT. Analysis of new experimental studies using synthetic solution containing NTA as the ligand and Cu(2+) ions shows that when the ionic strength is low (labile species measured using other dynamic sensors (DGT, GIME) in several freshwaters, it is concluded that in most waters ion transport in DMT is controlled by diffusion in the membrane. Only in very soft waters (<0.7 mM Ca+Mg), the dissociation rate of natural metal complex may influence ion transport in DMT. In this case, neglecting this effect may lead to an underestimation of the free metal ion concentration measured.

  14. Acid-Labile Amphiphilic PEO-b-PPO-b-PEO Copolymers: Degradable Poloxamer Analogs.

    PubMed

    Worm, Matthias; Kang, Biao; Dingels, Carsten; Wurm, Frederik R; Frey, Holger

    2016-05-01

    Poly ((ethylene oxide)-b-(propylene oxide)-b-(ethylene oxide)) triblock copolymers commonly known as poloxamers or Pluronics constitute an important class of nonionic, biocompatible surfactants. Here, a method is reported to incorporate two acid-labile acetal moieties in the backbone of poloxamers to generate acid-cleavable nonionic surfactants. Poly(propylene oxide) is functionalized by means of an acetate-protected vinyl ether to introduce acetal units. Three cleavable PEO-PPO-PEO triblock copolymers (Mn,total = 6600, 8000, 9150 g·mol(-1) ; Mn,PEO = 2200, 3600, 4750 g·mol(-1) ) have been synthesized using anionic ring-opening polymerization. The amphiphilic copolymers exhibit narrow molecular weight distributions (Ð = 1.06-1.08). Surface tension measurements reveal surface-active behavior in aqueous solution comparable to established noncleavable poloxamers. Complete hydrolysis of the labile junctions after acidic treatment is verified by size exclusion chromatography. The block copolymers have been employed as surfactants in a miniemulsion polymerization to generate polystyrene (PS) nanoparticles with mean diameters of ≈200 nm and narrow size distribution, as determined by dynamic light scattering and scanning electron microscopy. Acid-triggered precipitation facilitates removal of surfactant fragments from the nanoparticles, which simplifies purification and enables nanoparticle precipitation "on demand."

  15. Constraints on Transport and Emplacement Mechanisms of Labile Fractions in Lunar Cold Traps

    NASA Technical Reports Server (NTRS)

    Rickman, D.; Gertsch, L.

    2014-01-01

    Sustaining the scientific exploration of the Solar System will require a significant proportion of the necessary fuels and propellants, as well as other bulk commodities, to be produced from local raw materials [1]. The viability of mineral production depends on the ability to locate and characterize mineable deposits of the necessary feedstocks. This requires, among other things, a workable understanding of the mechanisms by which such deposits form, which is the subject of Economic Geology. Multiple deposition scenarios are possible for labile materials on the Moon. This paper suggests labile fractions moved diffusely through space; deposits may grow richer with depth until low porosity rock; lateral transport is likely to have occurred with the regolith, at least for short distances; crystalline ice may not exist; the constituent phases could be extremely complex. At present we can constrain the sources only mildly; once on the Moon, the transport mechanisms inherently mix and therefore obscure the origins. However, the importance of expanding our understanding of ore-forming processes on the Moon behooves us to make the attempt. Thus begins a time of new inquiry for Economic Geology.

  16. Localization of alkali-labile sites in donkey (Equus asinus) and stallion (Equus caballus) spermatozoa.

    PubMed

    Cortés-Gutiérrez, Elva I; Dávila-Rodríguez, Martha I; López-Fernández, Carmen; Fernández, José Luis; Crespo, Francisco; Gosálvez, Jaime

    2014-01-15

    The presence of constitutive alkali-labile sites (ALS) has been investigated using a protocol of DNA breakage detection-fluorescence in situ hybridization and comet assay in spermatozoa of donkey (Equus asinus) and stallion (Equus caballus). These results were compared with those obtained using a similar experimental approach using somatic cells. The relative abundance of ALS was of the order of four times more in spermatozoa than in somatic cells. Alkali-labile sites showed a tendency to cluster localized at the equatorial-distal regions of the sperm. The amount of hybridized signal in the ALS in the sperm of donkey (Equus asinus) was 1.3 times greater than in stallion (Equus caballus), and the length of the comet tail obtained in donkey sperm was 1.6 times longer than that observed in stallion (P < 0.05); however, these differences were not appreciated in somatic cells. In conclusion, ALS localization in sperm is not a randomized event and a different pattern of ALS distribution occurs for each species. These results suggest that ALS represents a species-specific issue related to chromatin organization in sperm and somatic cells in mammalian species, and they might diverge even with very short phylogenetic distances.

  17. Constrained lability in floral evolution: counting convergent origins of hummingbird pollination in Penstemon and Keckiella.

    PubMed

    Wilson, Paul; Wolfe, Andrea D; Armbruster, W Scott; Thomson, James D

    2007-01-01

    In the clade of Penstemon and segregate genera, pollination syndromes are well defined among the 284 species. Most display combinations of floral characters associated with pollination by Hymenoptera, the ancestral mode of pollination for this clade. Forty-one species present characters associated with hummingbird pollination, although some of these ornithophiles are also visited by insects. The ornithophiles are scattered throughout the traditional taxonomy and across phylogenies estimated from nuclear (internal transcribed spacer (ITS)) and chloroplast DNA (trnCD/TL) sequence data. Here, the number of separate origins of ornithophily is estimated, using bootstrap phylogenies and constrained parsimony searches. Analyses suggest 21 separate origins, with overwhelming support for 10 of these. Because species sampling was incomplete, this is probably an underestimate. Penstemons therefore show great evolutionary lability with respect to acquiring hummingbird pollination; this syndrome acts as an attractor to which species with large sympetalous nectar-rich flowers have frequently been drawn. By contrast, penstemons have not undergone evolutionary shifts backwards or to other pollination syndromes. Thus, they are an example of both striking evolutionary lability and constrained evolution.

  18. Novel diffusive gradients in thin films technique to assess labile sulfate in soil.

    PubMed

    Hanousek, Ondrej; Mason, Sean; Santner, Jakob; Chowdhury, Md Mobaroqul Ahsan; Berger, Torsten W; Prohaska, Thomas

    2016-09-01

    A novel diffusive gradients in thin films (DGT) technique for sampling labile soil sulfate was developed, based on a strong basic anion exchange resin (Amberlite IRA-400) for sulfate immobilization on the binding gel. For reducing the sulfate background on the resin gels, photopolymerization was applied instead of ammonium persulfate-induced polymerization. Agarose cross-linked polyacrylamide (APA) hydrogels were used as diffusive layer. The sulfate diffusion coefficient in APA gel was determined as 9.83 × 10(-6) ± 0.35 × 10(-6) cm(2) s(-1) at 25 °C. The accumulated sulfate was eluted in 1 mol L(-1) HNO3 with a recovery of 90.9 ± 1.6 %. The developed method was tested against two standard extraction methods for soil sulfate measurement. The obtained low correlation coefficients indicate that DGT and conventional soil test methods assess differential soil sulfate pools, rendering DGT a potentially important tool for measuring labile soil sulfate.

  19. [Effects of stand structure regulation on soil labile organic carbon in Pinus elliottii plantation].

    PubMed

    Tan, Gui-Xia; Liu, Yuan-Qiu; Li, Lian-Lian; Liu, Wu; Zan, Yu-Ting; Huo, Bing-Nan; He, Mu-Jiao

    2014-05-01

    Taking 21-year-old Pinus elliottii pure plantation as the control, effects of enrichment planting with broadleaf trees (Liquidambar fornosana) after thinning the conifer trees (P. elliottii) on soil labile organic carbon of different plantations, including 3-year-old, 6-year-old, 9-year-old P. elliottii and 21-year-old P. elliottii-L. fornosana mixed plantations, were investigated. The results showed that the contents of soil dissolved organic carbon (DOC), readily oxidizable organic carbon (ROC), and microbial biomass carbon (MBC) significantly increased in the 6-year-old and 9-year-old plantations compared with those in the 21-year-old P. elliottii pure plantation. Soil labile organic carbon contents in the 21-year-old P. elliottii-L. fornosana mixed plantation increased significantly than those in 3-year-old, 6-year-old, 9-year-old stands, and the DOC, ROC and MBC contents increased by 113.1%, 53.3% and 54.6%, respectively, compared with those in the 21-year-old P. elliottii pure plantation. The results suggested that replanting with broadleaf trees are an effective measure to improve the soil ecological function in pure P. elliottii plantation.

  20. [Effects of land use change on soil labile organic carbon in Central Jiangxi of China].

    PubMed

    Du, Man-Yi; Fan, Shao-Hui; Liu, Guang-Lu; Qi, Liang-Hua; Guo, Bao-Hu; Tang, Xiao-Lu; Xiao, Fu-Ming

    2013-10-01

    Selecting the 15-year abandoned land (AL) and three forest lands [Phyllostachys edulis plantation (PE), Schima superba secondary forest (SS), and Cunninghamia Lanceolata plantation (CL)] in Anfu County of Jiangxi Province as test objects, this paper studied the effects of land use change on the soil organic carbon (SOC) pool and soil labile organic carbon (SLOC) contents. The soil organic carbon (SOC), microbial biomass carbon (MBC), hot- water extractable carbon (HWC), and readily oxidizable carbon (ROC) contents in the test lands were all in the order of PE>CL>SS>AL. As compared with those in AL, the SOC content, soil carbon stock, and soil labile organic carbon (SLOC) contents in the three forest lands all decreased with increasing soil depth, and had an obvious accumulation in surface soil. The proportions of different kinds of SLOC to soil total organic carbon differed markedly, among which, ROC had the highest proportion, while MBC had the smallest one. There existed significant relationships between SOC, MBC, HWC, and ROC. The MBC, HWC, and ROC contained higher content of active carbon, and were more sensitive to the land use change, being able to be used as the indicators for evaluating the soil quality and fertility in central Jiangxi Province.

  1. Structure and function of cholera toxin and the related Escherichia coli heat-labile enterotoxin.

    PubMed Central

    Spangler, B D

    1992-01-01

    Cholera and the related Escherichia coli-associated diarrheal disease are important problems confronting Third World nations and any area where water supplies can become contaminated. The disease is extremely debilitating and may be fatal in the absence of treatment. Symptoms are caused by the action of cholera toxin, secreted by the bacterium Vibrio cholerae, or by a closely related heat-labile enterotoxin, produced by Escherichia coli, that causes a milder, more common traveler's diarrhea. Both toxins bind receptors in intestinal epithelial cells and insert an enzymatic subunit that modifies a G protein associated with the adenylate cyclase complex. The consequent stimulated production of cyclic AMP, or other factors such as increased synthesis of prostaglandins by intoxicated cells, initiates a metabolic cascade that results in the excessive secretion of fluid and electrolytes characteristic of the disease. The toxins have a very high degree of structural and functional homology and may be evolutionarily related. Several effective new vaccine formulations have been developed and tested, and a growing family of endogenous cofactors is being discovered in eukaryotic cells. The recent elucidation of the three-dimensional structure of the heat-labile enterotoxin has provided an opportunity to examine and compare the correlations between structure and function of the two toxins. This information may improve our understanding of the disease process itself, as well as illuminate the role of the toxin in studies of signal transduction and G-protein function. Images PMID:1480112

  2. Protective effects of dimethyl sulfoxide on labile protein interactions during electrospray ionization.

    PubMed

    Landreh, Michael; Alvelius, Gunvor; Johansson, Jan; Jörnvall, Hans

    2014-05-06

    Electrospray ionization mass spectrometry is a valuable tool to probe noncovalent interactions. However, the integrity of the interactions in the gas-phase is heavily influenced by the ionization process. Investigating oligomerization and ligand binding of transthyretin (TTR) and the chaperone domain from prosurfactant protein C, we found that dimethyl sulfoxide (DMSO) can improve the stability of the noncovalent interactions during the electrospray process, both regarding ligand binding and the protein quaternary structure. Low amounts of DMSO can reduce in-source dissociation of native protein oligomers and their interactions with hydrophobic ligands, even under destabilizing conditions. We interpret the effects of DMSO as being derived from its enrichment in the electrospray droplets during evaporation. Protection of labile interactions can arise from the decrease in ion charges to reduce the contributions from Coulomb repulsions, as well as from the cooling effect of adduct dissociation. The protective effects of DMSO on labile protein interactions are an important property given its widespread use in protein analysis by electrospray ionization mass spectrometry (ESI-MS).

  3. Towards powerful experimental and statistical approaches to study intraindividual variability in labile traits

    PubMed Central

    Fanson, Benjamin G.; Beckmann, Christa; Biro, Peter A.

    2016-01-01

    There is a long-standing interest in behavioural ecology, exploring the causes and correlates of consistent individual differences in mean behavioural traits (‘personality’) and the response to the environment (‘plasticity’). Recently, it has been observed that individuals also consistently differ in their residual intraindividual variability (rIIV). This variation will probably have broad biological and methodological implications to the study of trait variation in labile traits, such as behaviour and physiology, though we currently need studies to quantify variation in rIIV, using more standardized and powerful methodology. Focusing on activity rates in guppies (Poecilia reticulata), we provide a model example, from sampling design to data analysis, in how to quantify rIIV in labile traits. Building on the doubly hierarchical generalized linear model recently used to quantify individual differences in rIIV, we extend the model to evaluate the covariance between individual mean values and their rIIV. After accounting for time-related change in behaviour, our guppies substantially differed in rIIV, and it was the active individuals that tended to be more consistent (lower rIIV). We provide annotated data analysis code to implement these complex models, and discuss how to further generalize the model to evaluate covariances with other aspects of phenotypic variation. PMID:27853550

  4. Heat-Labile Enterotoxin IIa, a Platform To Deliver Heterologous Proteins into Neurons

    PubMed Central

    Chen, Chen; Przedpelski, Amanda; Tepp, William H.; Pellett, Sabine; Johnson, Eric A.

    2015-01-01

    ABSTRACT Cholera toxin (CT) and the related heat-labile enterotoxins (LT) of Escherichia coli have been implicated as adjuvants in human therapies, but reactivity upon intranasal delivery dampened efforts to develop other clinical applications. However, each CT family member variant has unique biological properties that may warrant development as therapeutic platforms. In the current study, a nontoxic variant of the heat-labile enterotoxin IIa (LTIIa) was engineered to deliver heterologous, functional proteins into the cytosol of neurons. As proof of principle, the LTIIa variant delivered two cargos into neurons. LTIIa delivered β-lactamase efficiently into cells containing complex gangliosides, such as GD1b, as host receptors. LTIIa delivery of β-lactamase was sensitive to brefeldin A, an inhibitor that collapses the Golgi compartment into the endoplasmic reticulum, but not sensitive to treatment with botulinum neurotoxin D (BoNT/D), an inhibitor of synaptic vesicle cycling. LTIIa delivered a single-chain, anti-BoNT/A camelid antibody that inhibited SNAP25 cleavage during post-BoNT/A exposure of neurons. Delivery of functional, heterologous protein cargos into neurons demonstrates the potential of LTII variants as platforms to deliver therapies to inactivate toxins and microbial infections and to reverse the pathology of human neurodegenerative diseases. PMID:26265718

  5. Analysis of remineralisation, lability, temperature sensitivity and structural composition of organic matter from the upper ocean

    NASA Astrophysics Data System (ADS)

    Bendtsen, Jørgen; Hilligsøe, Karen Marie; Hansen, Jørgen L. S.; Richardson, Katherine

    2015-01-01

    Organic carbon (OC) synthesised by plankton is exported out of the surface layer as particulate (POC) and dissolved (DOC) organic carbon. This 'biological pump' constitutes a major pathway in the global marine carbon cycle, each year exporting about 10 Pg C into the ocean interior, where it is subsequently remineralised via biological decomposition. Remineralised inorganic nutrients and carbon are, ultimately, again brought to the surface by advection and turbulent mixing which closes the OC-cycle in the upper ocean. Thus, remineralisation rates of OC are a critical component of the biological pump. These rates are regulated by the lability of the material and the environmental conditions in the ambient water. Temperature is particularly important in regulating the rate of microbial respiration and, thus, remineralisation rates. A significant temperature dependence of the microbial metabolic activity in the ocean interior is expected, as this is a feature observed elsewhere in the biosphere. Such temperature dependence of microbial remineralisation of POC and DOC will alter the amount of material available for transport by the biological pump to the deep ocean. Very few studies on the lability of OC and temperature sensitivity of microbial degradation processes in the mesopelagic zone (∼100-1000 m) have, to date, been carried out. Here, we present a comprehensive new experimental data set from all major ocean basins and quantify remineralisation rates of OC and their temperature sensitivity in long-term incubations of water from the upper 350 m. Microbial respiration was measured by non-invasive oxygen optodes and oxygen consumption was used as a constraint for determining the remineralisation rates and temperature sensitivity by two complementary methods. First, we analysed the oxygen consumption from a multi-component OC-model where the concentration, remineralisation rates and temperature sensitivity of two bio-available (labile) pools of organic carbon were

  6. Metal contents of phytoplankton and labile particulate material in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Twining, Benjamin S.; Rauschenberg, Sara; Morton, Peter L.; Vogt, Stefan

    2015-09-01

    Phytoplankton contribute significantly to global C cycling and serve as the base of ocean food webs. Phytoplankton require trace metals for growth and also mediate the vertical distributions of many metals in the ocean. We collected bulk particulate material and individual phytoplankton cells from the upper water column (<150 m) of the North Atlantic Ocean as part of the US GEOTRACES North Atlantic Zonal Transect cruise (GEOTRACES GA03). Particulate material was first leached to extract biogenic and potentially-bioavailable elements, and the remaining refractory material was digested in strong acids. The cruise track spanned several ocean biomes and geochemical regions. Particulate concentrations of metals associated primarily with lithogenic phases (Fe, Al, Ti) were elevated in surface waters nearest North America, Africa and Europe, and elements associated primarily with biogenic material (P, Cd, Zn, Ni) were also found at higher concentrations near the coasts. However metal/P ratios of labile particulate material were also elevated in the middle of the transect for Fe, Ni, Co, Cu, and V. P-normalized cellular metal quotas measured with synchrotron X-ray fluorescence (SXRF) were generally comparable to ratios in bulk labile particles but did not show mid-basin increases. Manganese and Fe ratios and cell quotas were higher in the western part of the section, nearest North America, and both elements were more enriched in bulk particles, relative to P, than in cells, suggesting the presence of labile oxyhydroxide particulate phases. Cellular Fe quotas thus did not increase in step with aeolian dust inputs, which are highest near Africa; these data suggest that the dust inputs have low bioavailability. Copper and Ni cell quotas were notably higher nearest the continental margins. Overall mean cellular metal quotas were similar to those measured in the Pacific and Southern Oceans except for Fe, which was approximately 3-fold higher in North Atlantic cells. Cellular Fe

  7. A Double Blind Trial of Divalproex Sodium for Affective Lability and Alcohol Use Following Traumatic Brain Injury

    DTIC Science & Technology

    2010-10-01

    ameliorate agitation and disinhibited behavior as well as depression and manic symptoms following TBI. (Azouvi et al., 1999; Bakchine et al., 1989; Perino et...courses as do Major Depressive Disorder, Bipolar Illness , or Anxiety Disorder, for example. Instead both symptoms and course appear more...lithium or carbamazepine to prevent recurrent manic or depressive episodes during long-term treatment of bipolar disorder (PDR, 2006). This line of

  8. A Double Blind Trial of Divalproex Sodium for Affective Lability and Alcohol Use Following Traumatic Brain Injury

    DTIC Science & Technology

    2013-10-01

    disinhibited behavior as well as depression and manic symptoms following TBI. (Azouvi et al., 1999; Bakchine et al., 1989; Perino et al., 2001) Valproate may... Depressive Disorder, Bipolar Illness , or Anxiety Disorder, for example. Instead both symptoms and course appear more characteristic of the sustained...prevent recurrent manic or depressive episodes during long-term treatment of bipolar disorder (PDR, 2006). This line of research opens an exciting

  9. Toward a definition of affective instability.

    PubMed

    Renaud, Suzane M; Zacchia, Camillo

    2012-01-01

    Affective instability is a psychophysiological symptom observed in some psychopathologies. It is a complex construct that encompasses (1) primary emotions, or affects, and secondary emotions, with each category having its own characteristics, amplitude, and duration, (2) rapid shifting from neutral or valenced affect to intense affect, and (3) dysfunctional modulation of emotions. Affective instability is often confused with mood lability, as in bipolar disorders, as well as with other terms. To clarify the concept, we searched databases for the term affective instability and read related articles on the topic. In this article we situate the term within the current affective nomenclature and human emotional experience, explore its psychophysiological features, and place it within the context of psychopathology. We explain why the term can potentially be confused with mood pathology and then define affective instability as an inherited temperamental trait modulated by developmental experience.

  10. Comparison of Y1 mouse adrenal cell and coagglutination assays for detection of Escherichia coli heat labile enterotoxin.

    PubMed Central

    Chapman, P A; Daly, C M

    1989-01-01

    A commercial coagglutination assay (COA; Phadebact LT-ETEC) was compared with a Y1 mouse adrenal cell assay for detecting the heat labile enterotoxin of Escherichia coli. Of four different media evaluated for use with the COA, only one (modified blood agar) gave a positive result with all strains known to produce heat labile enterotoxin. With modified blood agar, the COA detected 74 (85%) of 87 such strains. Eighty six strains negative by cell culture assay were also negative by COA, and one strain positive by COA could not be confirmed by cell culture. The Phadebact LT-ETEC kit provides a simple, sensitive, and economical method for detecting E coli heat labile enterotoxin. PMID:2668342

  11. The role of affect-driven impulsivity in gambling cognitions: A convenience-sample study with a Spanish version of the Gambling-Related Cognitions Scale.

    PubMed

    Del Prete, Francesco; Steward, Trevor; Navas, Juan F; Fernández-Aranda, Fernando; Jiménez-Murcia, Susana; Oei, Tian P S; Perales, José C

    2017-03-01

    Background and aims Abnormal cognitions are among the most salient domain-specific features of gambling disorder. The aims of this study were: (a) to examine and validate a Spanish version of the Gambling-Related Cognitions Scale (GRCS; Raylu & Oei, 2004) and (b) to examine associations between cognitive distortion levels, impulsivity, and gambling behavior. Methods This study first recruited a convenience sample of 500 adults who had gambled during the previous year. Participants were assessed using the Spanish version of GRCS (GRCS-S) questionnaire, the UPPS-P impulsivity questionnaire, measures of gambling behavior, and potentially relevant confounders. Robust confirmatory factor analysis methods on half the sample were used to select the best models from a hypothesis-driven set. The best solutions were validated on the other half, and the resulting factors were later correlated with impulsivity dimensions (in the whole n = 500 factor analysis sample) and clinically relevant gambling indices (in a separate convenience sample of 137 disordered and non-disordered gamblers; validity sample). Results This study supports the original five-factor model, suggests an alternative four-factor solution, and confirms the psychometric soundness of the GRCS-S. Importantly, cognitive distortions consistently correlated with affect- or motivation-driven aspects of impulsivity (urgency and sensation seeking), but not with cognitive impulsivity (lack of premeditation and lack of perseverance). Discussion and conclusions Our findings suggest that the GRCS-S is a valid and reliable instrument to identify gambling cognitions in Spanish samples. Our results expand upon previous research signaling specific associations between gambling-related distortions and affect-driven impulsivity in line with models of motivated reasoning.

  12. Examining the relationship between personality and affect-related attributes and adolescents' intentions to try smoking using the Substance Use Risk Profile Scale.

    PubMed

    Memetovic, Jasmina; Ratner, Pamela A; Gotay, Carolyn; Richardson, Christopher G

    2016-05-01

    Assessments of adolescents' smoking intentions indicate that many are susceptible to smoking initiation because they do not have resolute intentions to abstain from trying smoking in the future. Although researchers have developed personality and affect-related risk factor profiles to understand risk for the initiation of substance use and abuse (e.g., alcohol), few have examined the extent to which these risk factors are related to the tobacco use intentions of adolescents who have yet to try tobacco smoking. The objective of this study was to examine the relationships between personality and affect-related risk factors measured by the Substance Use Risk Profile Scale (SURPS) and smoking intentions in a sample of adolescents who have not experimented with tobacco smoking. Data is based on responses from 1352 participants in the British Columbia Adolescent Substance Use Survey (56% female, 76% in Grade 8) who had never tried smoking tobacco. Of these 1352 participants, 29% (n=338) were classified as not having resolute intentions to not try smoking. Generalized estimating equations were used to examine the relationship between each SURPS dimension (Anxiety Sensitivity, Hopelessness, Impulsivity and Sensation Seeking) and the intention to try cigarettes in the future. Hopelessness (AOR 1.06, 95% CI [1.03, 1.10], p<.001), Impulsivity (AOR 1.07 [1.03, 1.11], p<.001) and Sensation Seeking (AOR 1.05 95% CI [1.02, 1.09], p<.01) had independent statistically significant associations with having an intention to try smoking. These findings may be used to inform a prevention-oriented framework to reduce susceptibility to tobacco smoking.

  13. Labile trace elements in basaltic achondrites: Can they distinguish between meteorites from the Moon, Mars, and V-type asteroids?

    NASA Astrophysics Data System (ADS)

    Wolf, Stephen F.; Wang, Ming-Sheng; Lipschutz, Michael E.

    2009-06-01

    We report data for 14 mainly labile trace elements (Ag, Au, Bi, Cd, Cs, Ga, In, Rb, Sb, Se, Te, Tl, U, and Zn) in eight whole-rock lunar meteorites (Asuka [A-] 881757, Dar al Gani [DaG] 262, Elephant Moraine [EET] 87521, Queen Alexandra Range [QUE] 93069, QUE 94269, QUE 94281, Yamato [Y-] 793169, and Y-981031), and Martian meteorite (DaG 476) and incorporate these into a comparative study of basaltic meteorites from the Moon, Mars, and V-type asteroids. Multivariate cluster analysis of data for these elements in 14 lunar, 13 Martian, and 34 howardite, eucrite, and diogenite (HED) meteorites demonstrate that materials from these three parents are distinguishable using these markers of late, low-temperature episodes. This distinguishability is essentially as complete as that based on markers of high-temperature igneous processes. Concentrations of these elements in 14 lunar meteorites are essentially lognormally distributed and generally more homogeneous than in Martian and HED meteorites. Mean siderophile and labile element concentrations in the 14 lunar meteorites indicate the presence of a CI-equivalent micrometeorite admixture of 2.6% When only feldspathic samples are considered, our data show a slightly higher value of 3.4% consistent with an increasing micrometeorite content in regolith samples of higher maturity. Concentrations of labile elements in the 8 feldspathic samples hint at the presence of a fractionated highly labile element component, possibly volcanic in origin, at a level comparable to the micrometeorite component. Apparently, the process(es) that contributed to establishing lunar meteorite siderophile and labile trace element contents occurred in a system open to highly labile element transport.

  14. Langley Full-scale-tunnel Investigation of the Factors Affecting the Static Lateral-stability Characteristics of a Typical Fighter-type Airplane

    NASA Technical Reports Server (NTRS)

    Lange, Roy H

    1947-01-01

    The factors that affect the rate of change of rolling moment with yaw of a typical fighter-type airplane were investigated in the Langley full-scale tunnel on a typical fighter-type airplane.Eight representative flight conditions were investigated in detail. The separate effects of propeller operation, of the wing-fuselage combination, and of the vertical tail to the effective dihedral of the airplane in each condition were determined. The results of the tests showed that for the airplane with the propeller removed, the wing-fuselage combination had positive dihedral effect which increased considerably with increasing angle of attack for all conditions. Flap deflection decreased the dihedral effect of the wing-fuselage combination slightly as compared with that with the flaps retracted. Flap deflection resulted in negative dihedral effect due to the vertical tail. Propeller operation decreased the lateral stability parameter of the airplane for all the conditions investigated with larger decreases being measured for the flaps deflected conditions.

  15. Significance of Isotopically Labile Organic Hydrogen in Thermal Maturation of Organic Matter

    SciTech Connect

    Arndt Schimmelmann; Maria Mastalerz

    2010-03-30

    Isotopically labile organic hydrogen in fossil fuels occupies chemical positions that participate in isotopic exchange and in chemical reactions during thermal maturation from kerogen to bitumen, oil and gas. Carbon-bound organic hydrogen is isotopically far less exchangeable than hydrogen bound to nitrogen, oxygen, or sulfur. We explore why organic hydrogen isotope ratios express a relationship with organic nitrogen isotope ratios in kerogen at low to moderate maturity. We develop and apply new techniques to utilize organic D/H ratios in organic matter fractions and on a molecular level as tools for exploration for fossil fuels and for paleoenvironmental research. The scope of our samples includes naturally and artificially matured substrates, such as coal, shale, oil and gas.

  16. Bioavailability of labile and desorption-resistant phenanthrene sorbed to montmorillonite clay containing humic fractions

    SciTech Connect

    Lahlou, M.; Ortega-Calvo, J.J.

    1999-12-01

    The biodegradation of {sup 14}C-labeled phenanthrene in the presence of particles of montmorillonite and fulvic and humic acid-montmorillonite complexes was studied in a batch system. A mathematical model that takes into account the contribution to mineralization by the slowly desorbing compound was used to calculate the initial mineralization rates. Sorption of phenanthrene to the particles was determined in sorption isotherms, and desorption was measured during successive water extractions. Mineralization rates in equilibrated suspensions were higher than predicted from aqueous equilibrium concentrations, and in some cases, montmorillonite and fulvic acid-montmorillonite complexes stimulated the phenanthrene transformation rates. In contrast with the high bioavailability exhibited by phenanthrene sorbed as a labile form, biodegradation of the desorption-resistant phenanthrene occurred slowly and followed zero-order kinetics, which indicated a limitation caused by slow desorption. The results suggest that the mechanism of sorption may cause a differential bioavailability of the sorbed compound.

  17. Phenotypic lability and the evolution of predator-induced plasticity in tadpoles.

    PubMed

    Van Buskirk, J

    2002-02-01

    The hypothesis that predator-induced defenses in anuran larvae are maintained by divergent selection across multiple predation environments has not been fully supported by empirical results. One reason may be that traits that respond slowly to environmental variation experience a fitness cost not incorporated in the standard adaptive model, due to a time lag between detecting the state of the environment and expressing the phenotypic response. I measured the rate at which behavior and morphology of Rana temporaria tadpoles change when confronted with a switch in the predation environment at two points in development. Hatchling tadpoles that had been exposed during the egg stage to Aeshna dragonfly larvae were not phenotypically different from those exposed as eggs to predator-free conditions, and both responded similarly to post-hatching predator treatments. When 25-day-old tadpoles from treatments with and without dragonflies were subjected to a switch in the environment, their activity budgets reversed completely within 24-36 h, and their body and tail shape began changing significantly within 4 days. The behavioral response was conservative: Tadpoles switched from high-risk to predator-free treatments were slower to adjust their activity. The study confirmed that behavioral traits are relatively labile and exhibit strong plasticity, but it did not reveal such a pattern at the level of individual traits: Morphological traits that developed slowly did not show the least plasticity. Thus, I found that differences in lability of traits were useful for predicting the magnitude of plasticity only for fundamentally different kinds of characters.

  18. Molecular insights into the microbial formation of marine dissolved organic matter: recalcitrant or labile?

    NASA Astrophysics Data System (ADS)

    Koch, B. P.; Kattner, G.; Witt, M.; Passow, U.

    2014-02-01

    The degradation of marine dissolved organic matter (DOM) is an important control variable in the global carbon cycle and dependent on the DOM composition. For our understanding of the kinetics of organic matter cycling in the ocean, it is therefore crucial to achieve a mechanistic and molecular understanding of its transformation processes. A long-term microbial experiment was performed to follow the production of non-labile DOM by marine bacteria. Two different glucose concentrations and dissolved algal exudates were used as substrates. We monitored the bacterial abundance, concentrations of dissolved and particulate organic carbon (DOC, POC), nutrients, amino acids, and transparent exopolymer particles (TEP) for two years. Ultrahigh resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS) allowed the molecular characterization of extracted DOM after 70 days and after ∼2 years of incubation. Although glucose was quickly degraded, a DOC background was generated in glucose incubations. Only 20% of the organic carbon from algal exudate was degraded within the 2 years of incubation. TEP, which are released by micro-organisms, were produced during glucose degradation but decreased within less than three weeks back to half of the maximum concentration and were below detection in all treatments after 2 years. The molecular analysis demonstrated that DOM generated during glucose degradation differed appreciably from DOM produced during the degradation of the algal exudates. Our results led to several conclusions: (i) Higher substrate levels result in a higher level of non-labile DOC which is an important prerequisite for carbon sequestration in the ocean; (ii) TEP are generated by bacteria but are also degraded rapidly, thus limiting their potential contribution to carbon sequestration; (iii) The molecular signatures of DOM derived from algal exudates or glucose after 70 days of incubation differed strongly from refractory DOM. After 2 years

  19. Oxidative stress and labile plasmatic iron in anemic patients following blood therapy

    PubMed Central

    Fernandes, Marília Sabo; Rissi, Tatiana Tamborena; Zuravski, Luisa; Mezzomo, Juliana; Vargas, Carmen Regla; Folmer, Vanderlei; Soares, Félix Alexandre Antunes; Manfredini, Vanusa; Ahmed, Mushtaq; Puntel, Robson Luiz

    2014-01-01

    AIM: To determine the plasmatic iron content and evaluate the oxidative stress (OS) markers in subjects receiving blood therapy. METHODS: Thirty-nine individuals with unspecified anemia receiving blood transfusions and 15 healthy subjects were included in the study. Anemic subjects were divided into three subgrouP: (1) those that received up to five blood transfusions (n = 14); (2) those that received from five to ten transfusions (n = 11); and (3) those that received more than ten transfusions (n = 14). Blood samples were collected by venous arm puncture and stored in tubes containing heparin. The plasma and cells were separated by centrifugation and subsequently used for analyses. Statistical analyses were performed using Kruskal-Wallis analysis of variance followed by Dunn’s multiple comparison tests when appropriate. RESULTS: The eletrophoretic hemoglobin profiles of the subjects included in this study indicated that no patients presented with hemoglobinopathy. Labile plasmatic iron, ferritin, protein carbonyl, thiobarbituric acid-reactive substances (TBARS) and dichlorofluorescein diacetate oxidation were significantly higher (P < 0.05), whereas total thiol levels were significantly lower (P < 0.05) in transfused subjects compared to controls. Additionally, the activity of catalase, superoxide dismutase and glutathione peroxidase were significantly lower in the transfused subjects (P < 0.05). Antioxidant enzyme activities and total thiol levels were positively correlated (P < 0.05), and negatively correlated with the levels of protein carbonyl and TBARS (P < 0.05). In contrast, protein carbonyl and TBARS were positively correlated (P < 0.05). Altogether, these data confirm the involvement of OS in patients following therapy with repeated blood transfusions. CONCLUSION: Our data reveal that changes in OS markers are correlated with levels of labile plasmatic iron and ferritin and the number of transfusions. PMID:25254188

  20. Temporal Changes in Photochemically Labile DOM and Implications for Carbon Budgets in Peatland Aquatic Systems

    NASA Astrophysics Data System (ADS)

    Pickard, A.

    2015-12-01

    Aquatic systems in peatland catchments are subject to high loading of dissolved organic matter (DOM) from surrounding terrestrial environments. However the significance of photochemical transformation of DOM in peatland carbon budgets remains poorly constrained. In this study UV irradiation experiments were conducted on water samples collected over one year from two contrasting systems in Scotland: a stream draining a peatland with high levels of DOM and a reservoir draining a peat catchment with low levels of DOM. Further samples were collected from the high DOM system during two storm events. After experimental exposure, optical and chemical analyses were employed to determine photochemical lability of the DOM pool. At both sites irradiation-induced decreases in dissolved organic carbon (DOC) as a percentage of the total carbon pool were greatest in winter, suggesting that DOM was depleted in photo-reactive molecules in summer. Seasonal variability in DOC was high at the stream site and was positively correlated with CO₂ and CO photoproduction (r2 = 0.81 and 0.83, respectively; p<0.05). Lignin phenol analyses indicate considerable contribution of peat to the DOM pool at the stream site, particularly during summer. Whilst DOC concentrations did not vary greatly during storm events, UV-Vis absorbance indicators did, signifying changing DOM source material from activation of different hydrological pathways. The most photo-reactive DOM occurred 5-10 hours after peak discharge, suggesting that storms replenish photochemically labile DOM in headwater streams. Conservative estimates using data from this study suggest that up to 7% of the DOM pool of peatland streams can be lost (primarily as CO₂ and CO) upon exposure to 8 hours of environmentally representative UV irradiation. Further investigation in field campaigns under natural UV exposure are underway to assess the importance of photodegradation of DOM as a loss pathway of carbon based gases from aquatic systems.

  1. In vivo lability of glucose-6-phosphate dehydrogenase in GdA- and Gdmediterranean deficiency

    PubMed Central

    Piomelli, Sergio; Corash, Laurence M.; Davenport, Deatra D.; Miraglia, Janet; Amorosi, Edward L.

    1968-01-01

    A decreased level of glucose-6-phosphate dehydrogenase might result from decreased rate of synthesis, synthesis of an enzyme of lower catalytic efficiency, increased lability, or a combined mechanism. To test the hypothesis of increased lability, the rate of decline of the enzyme in vivo was measured in three groups of individuals, controls, Gd(—),A-males, and Gd(—), Mediterranean males, by the slope of decline of activity in fractions containing erythrocytes of progressively increasing mean age. These fractions were obtained by ultracentrifugation on a discontinuous density gradient of erythrocyte suspensions free of contaminating platelets and leukocytes. The rate of in vivo decline of pyruvate kinase (another age-dependent enzyme) was also measured and found very similar in the three groups. The in vivo decline of glucose-6-phosphate dehydrogenase was found to follow an exponential rate, with a half-life of 62 days for controls and 13 days for Gd(—),A- erythrocytes. The activity in normal reticulocytes was estimated at 9.7 U and in Gd(—),A- reticulocytes at 8.8 U. These estimates were confirmed by direct measurements in reticulocytes isolated from patients with extreme reticulocytosis. In Gd(—),Mediterranean erythrocytes activity could be demonstrated only in reticulocytes, which were estimated to average 1.4 U. The rate of decline is so extreme that no activity could be detected in mature erythrocytes. These data suggest that the glucose-6-phosphate dehydrogenase deficiency of both the GdA- and the GdMediterranean variant results from different degrees of in vivo instability of the abnormal enzyme. PMID:5641629

  2. Collagenase-labile polyurethane urea synthesis and processing into hollow fiber membranes.

    PubMed

    Fu, Hui-Li; Hong, Yi; Little, Steven R; Wagner, William R

    2014-08-11

    As a means to stimulate wound healing, a hollow fiber membrane system might be placed within a wound bed to provide local and externally regulated controlled delivery of regenerative factors. After sufficient healing, it would be desirable to triggerably degrade these fibers as opposed to pulling them out. Accordingly, a series of enzymatically degradable thermoplastic elastomers was developed as potential hollow fiber base material. Polyurethane ureas (PUUs) were synthesized based on 1, 4-diisocyanatobutane, polycaprolactone (PCL) diol and polyethylene glycol (PEG) at different molar fractions as soft segments, and collagenase-sensitive peptide GGGLGPAGGK-NH2 as a chain extender (defined as PUU-CLxEGy-peptide, where x and y are the respective molar percents). In these polymers, PEG in the polymer backbone decreased tensile strengths and initial moduli of solvent-cast films in the wet state, while increasing water absorption. Collagenase degradation was observed at 75% relative PEG content in the soft segment. Control PUUs with putrescine or nonsense peptide chain extenders did not degrade acutely in collagenase. Conduits electrospun from PUU-CL25EG75-peptide and PUU-CL50EG50-peptide exhibited appropriate mechanical strength and sustained release of a model protein from the tube lumen for 7 days. Collapse of PUU-CL25EG75-peptide tubes occurred after collagenase degradation for 3 days. In conclusion, through molecular design, synthesis and characterization, a collagenase-labile PUU-CL25EG75-peptide polymer was identified that exhibited the desired traits of triggerable lability, processability, and the capacity to act as a membrane to facilitate controlled protein release.

  3. How landscape scale changes affect ecological processes in conservation areas: external factors influence land use by zebra (Equus burchelli) in the Okavango Delta

    PubMed Central

    Bartlam-Brooks, Hattie L A; Bonyongo, Mpaphi C; Harris, Stephen

    2013-01-01

    Most large-bodied wildlife populations in sub-Saharan Africa only survive in conservation areas, but are continuing to decline because external changes influence ecological processes within reserves, leading to a lack of functionality. However, failure to understand how landscape scale changes influence ecological processes limits our ability to manage protected areas. We used GPS movement data to calculate dry season home ranges for 14 zebra mares in the Okavango Delta and investigated the effects of a range of landscape characteristics (number of habitat patches, mean patch shape, mean index of juxtaposition, and interspersion) on home range size. Resource utilization functions (RUF) were calculated to investigate how specific landscape characteristics affected space use. Space use by all zebra was clustered. In the wetter (Central) parts of the Delta home range size was negatively correlated with the density of habitat patches, more complex patch shapes, low juxtaposition of habitats and an increased availability of floodplain and grassland habitats. In the drier (Peripheral) parts of the Delta, higher use by zebra was also associated with a greater availability of floodplain and grassland habitats, but a lower density of patches and simpler patch shapes. The most important landscape characteristic was not consistent between zebra within the same area of the Delta, suggesting that no single foraging strategy is substantially superior to others, and so animals using different foraging strategies may all thrive. The distribution and complexity of habitat patches are crucial in determining space use by zebra. The extent and duration of seasonal flooding is the principal process affecting habitat patch characteristics in the Okavango Delta, particularly the availability of floodplains, which are the habitat at greatest risk from climate change and anthropogenic disturbance to the Okavango's catchment basin. Understanding how the factors that determine habitat

  4. How landscape scale changes affect ecological processes in conservation areas: external factors influence land use by zebra (Equus burchelli) in the Okavango Delta.

    PubMed

    Bartlam-Brooks, Hattie L A; Bonyongo, Mpaphi C; Harris, Stephen

    2013-09-01

    Most large-bodied wildlife populations in sub-Saharan Africa only survive in conservation areas, but are continuing to decline because external changes influence ecological processes within reserves, leading to a lack of functionality. However, failure to understand how landscape scale changes influence ecological processes limits our ability to manage protected areas. We used GPS movement data to calculate dry season home ranges for 14 zebra mares in the Okavango Delta and investigated the effects of a range of landscape characteristics (number of habitat patches, mean patch shape, mean index of juxtaposition, and interspersion) on home range size. Resource utilization functions (RUF) were calculated to investigate how specific landscape characteristics affected space use. Space use by all zebra was clustered. In the wetter (Central) parts of the Delta home range size was negatively correlated with the density of habitat patches, more complex patch shapes, low juxtaposition of habitats and an increased availability of floodplain and grassland habitats. In the drier (Peripheral) parts of the Delta, higher use by zebra was also associated with a greater availability of floodplain and grassland habitats, but a lower density of patches and simpler patch shapes. The most important landscape characteristic was not consistent between zebra within the same area of the Delta, suggesting that no single foraging strategy is substantially superior to others, and so animals using different foraging strategies may all thrive. The distribution and complexity of habitat patches are crucial in determining space use by zebra. The extent and duration of seasonal flooding is the principal process affecting habitat patch characteristics in the Okavango Delta, particularly the availability of floodplains, which are the habitat at greatest risk from climate change and anthropogenic disturbance to the Okavango's catchment basin. Understanding how the factors that determine habitat

  5. Factors affecting the willingness of nursing students to receive annual seasonal influenza vaccination: A large-scale cross-sectional study.

    PubMed

    Cheung, Kin; Ho, Sin Man Simone; Lam, Winsome

    2017-03-13

    Nursing students are at high risk of exposure to vaccine-preventable diseases such as seasonal influenza. However, due to the limited number of studies conducted in this area, the prevalence and factors affecting annual seasonal influenza vaccination (ASIV) uptake remain unclear. This was a large-scale cross-sectional survey study conducted among 902 nursing students in different years of study. The questionnaire was developed based on the Health Belief Model (HBM), and logistic regression was used to determine the predictors of ASIV uptake. The results of our study reveal that only 15.2% of nursing students declared having the vaccine in the previous year, and that ASIV uptake was self-reported. ASIV uptake was associated with perceived susceptibility (odds ratio=2.76), perceived seriousness (odds ratio=2.06) and perceived barriers (odds ratio=0.50). The odds of receiving ASIV were 17.96times higher for those participants having had ASIV at least once than those who had not received ASIV in the previous five years. In addition, the odds of receiving ASIV were 4.01times higher for master's than undergraduate students. Our study concludes that the ASIV uptake among nursing students is low. In order to increase vaccination uptake in subsequent years, future studies should promote vaccination based on HBM, focusing on nursing students in undergraduate studies by emphasizing not only vaccination knowledge, but also their social responsibility to protect patients. Influenza vaccination can be viewed as an ethical professional responsibility and a patient safety issue, as well as being an infection control strategy.

  6. Estimating rates and patterns of morphological evolution from phylogenies: lessons in limb lability from Australian Lerista lizards.

    PubMed

    Wiens, John J

    2009-01-01

    Squamates (lizards and snakes) offer an exciting model system for research on the evolution of body form. A new phylogenetic study in BMC Evolutionary Biology of Australian lizards shows remarkable evolutionary lability in digit numbers among closely related species, but also highlights important challenges in this area.

  7. On the Labile Memory Buffer in the Attentional Blink: Masking the T2 Representation by Onset Transients Mediates the AB

    ERIC Educational Resources Information Center

    Jannati, Ali; Spalek, Thomas M.; Di Lollo, Vincent

    2011-01-01

    Report of a second target (T2) is impaired when presented within 500 ms of the first (T1). This attentional blink (AB) is known to cause a delay in T2 processing during which T2 must be stored in a labile memory buffer. We explored the buffer's characteristics using different types of masks after T2. These characteristics were inferred by…

  8. Size-optimized galactose-capped gold nanoparticles for the colorimetric detection of heat-labile enterotoxin at nanomolar concentrations.

    PubMed

    Poonthiyil, Vivek; Golovko, Vladimir B; Fairbanks, Antony J

    2015-05-14

    The development of a galactose-capped gold nanoparticle-based colorimetric sensor for the detection of the lectin heat-labile enterotoxin is reported. Heat-labile enterotoxin is one of the pathogenic agents responsible for the intestinal disease called 'traveller's diarrhoea'. By means of specific interaction between galactose moieties attached to the surface of gold nanoparticles and receptors on the B-subunit of heat-labile enterotoxin (LTB), the gold nanoparticles reported here act as an efficient colorimetric sensor, which can detect the toxin at nanomolar concentrations. The effect of gold nanoparticle size on the detection sensitivity was investigated in detail. Amongst the various sizes of gold nanoparticles studied (2, 7, 12, and 20 nm), the 12 nm sized gold nanoparticles were found to be the most efficient, with a minimum heat-labile enterotoxin detection concentration of 100 nM. The red to purple colour change of the gold nanoparticle solution occurred within two minutes, indicating rapid toxin sensing.

  9. An anaerobic incubation study of metal lability in drinking water treatment residue with implications for practical reuse.

    PubMed

    Wang, Changhui; Yuan, Nannan; Pei, Yuansheng

    2014-06-15

    Drinking water treatment residue (WTR) is an inevitable by-product generated during the treatment of drinking water with coagulating agents. The beneficial reuse of WTR as an amendment for environmental remediation has attracted growing interest. In this work, we investigated the lability of Al, As, Ba, Be, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Pb, Sr, V and Zn in Fe/Al hydroxide-comprised WTR based on a 180-day anaerobic incubation test using fractionation, in vitro digestion and a toxicity characteristic leaching procedure. The results indicated that most metals in the WTR were stable during anaerobic incubation and that the WTR before and after incubation could be considered non-hazardous in terms of leachable metal contents according to US EPA Method 1311. However, the lability of certain metals in the WTR after incubation increased substantially, especially Mn, which may be due to the reduction effect. Therefore, although there is no evidence presented to restrict the use of WTR in the field, the lability of metals (especially Mn) in WTR requires further assessment prior to field application. In addition, fractionation (e.g., BCR) is recommended for use to determine the potential lability of metals under various conditions.

  10. Analysis and modeling of heat-labile enterotoxins of Escherichia coli suggests a novel space with insights into receptor preference.

    PubMed

    Krishna Raja, M; Ghosh, Asit Ranjan; Vino, S; Sajitha Lulu, S

    2015-01-01

    Features of heat-labile enterotoxins of Escherichia coli which make them fit to use as novel receptors for antidiarrheals are not completely explored. Data-set of 14 different serovars of enterotoxigenic Escherichia coli producing heat-labile toxins were taken from NCBI Genbank database and used in the study. Sequence analysis showed mutations in different subunits and also at their interface residues. As these toxins lack crystallography structures, homology modeling using Modeller 9.11 led to the structural approximation for the E. coli producing heat-labile toxins. Interaction of modeled toxin subunits with proanthocyanidin, an antidiarrheal showed several strong hydrogen bonding interactions at the cost of minimized energy. The hits were subsequently characterized by molecular dynamics simulation studies to monitor their binding stabilities. This study looks into novel space where the ligand can choose the receptor preference not as a whole but as an individual subunit. Mutation at interface residues and interaction among subunits along with the binding of ligand to individual subunits would help to design a non-toxic labile toxin and also to improve the therapeutics.

  11. Forms and lability of phosphorus in algae and aquatic macrophytes characterized by solution 31P NMR coupled with enzymatic hydrolysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increased information on forms and lability of phosphorus (P) in aquatic macrophytes and algae is crucial for better understanding of P biogeochemical cycling in eutrophic lakes. In this work, solution 31P nuclear magnetic resonance (NMR) spectroscopy coupled with enzymatic hydrolysis (EH) was used ...

  12. Tillage and rotational effects on exchangeable and enzyme-labile phosphorus forms in conventional and organic cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The transformations of crop residues and bio-fertilizers used as primary sources of nutrients for organic grain and forage production are influenced by soil management practices. The effects of management of the near-surface zone on labile phosphorus (P) forms were studied in soil under three organ...

  13. Further characterization of some heterophile agglutinins reacting with alkali-labile carbohydrate chains of human erythrocyte glycoproteins.

    PubMed

    Dahr, W; Uhlenbruck, G; Bird, G W

    1975-01-01

    The nature of the receptor sites for several agglutinins is characterized by hemagglutination inhibition assays. The inhibitory activity of human erythrocytes glycoproteins, from which sialic acid, sialic acid and galactose or alkali-labile oligosaccharides have been removed, is compared to the inhibitory effect of compounds with known structure. It is shown that the lectin from Arachis hypogea and anti-T bind to alkali-labile galactosyl-residues. Agglutinins from Bauhinia purpurea and variegata (non- or N-specific), Maclura aurantiaca, Iberis amara, sempervirens, umbellata hybrida and umbellata nana (M- or nonspecific), Moluccella laevis (A- plus N-specific), Helix pomatia, Helix aspersa, Helix lucorum and Caucasotachea atrolabiata interact with alkali-labile N-acetylgalactosamine. The results obtained with the anti-A agglutinins from various snails suggest that human erythrocyte glycoproteins contain, besides the alkali-labile tetrasaccharide, a peptide-linked sialyl-N-acetyl-galactosaminyl-residue. The investigations do not allow a precise definition of the receptor sites for the lectins having M- or N-specificity.

  14. Rapid latex particle agglutination test for Escherichia coli strains of porcine origin producing heat-labile enterotoxin.

    PubMed Central

    Finkelstein, R A; Yang, Z S; Moseley, S L; Moon, H W

    1983-01-01

    A latex particle agglutination test previously shown to be suitable for the rapid identification of Escherichia coli strains of human origin producing heat-labile enterotoxin (R. A. Finkelstein and Z. Yang, J. Clin. Microbiol. 18:23-28) is equally applicable to strains of porcine origin. PMID:6361056

  15. Thermal Analysis of Labile Trace Elements in CM and CV Carbonaceous Chondrites Using Inductively Coupled Plasma-Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Lauretta, D. S.; Klaue, B.; Blum, J. D.; Buseck, P. R.

    2001-01-01

    We developed a technique to measure the thermal release profiles of a suite of labile elements (Zn, As, Se, Cd, In, Sn, Sb, Te, Pt, Hg, Au, Tl, Pb, Bi). Conclusions are reached about the behavior of each element during parent-body alteration. Additional information is contained in the original extended abstract.

  16. Emotional Lability in Children and Adolescents with Attention Deficit/Hyperactivity Disorder (ADHD): Clinical Correlates and Familial Prevalence

    ERIC Educational Resources Information Center

    Sobanski, Esther; Banaschewski, Tobias; Asherson, Philip; Buitelaar, Jan; Chen, Wai; Franke, Barbara; Holtmann, Martin; Krumm, Bertram; Sergeant, Joseph; Sonuga-Barke, Edmund; Stringaris, Argyris; Taylor, Eric; Anney, Richard; Ebstein, Richard P.; Gill, Michael; Miranda, Ana; Mulas, Fernando; Oades, Robert D.; Roeyers, Herbert; Rothenberger, Aribert; Steinhausen, Hans-Christoph; Faraone, Stephen V.

    2010-01-01

    Background: The goal of this study was to investigate the occurrence, severity and clinical correlates of emotional lability (EL) in children with attention deficit/hyperactivity disorder (ADHD), and to examine factors contributing to EL and familiality of EL in youth with ADHD. Methods: One thousand, one hundred and eighty-six children with ADHD…

  17. A Longitudinal Study of Emotion Regulation, Emotion Lability-Negativity, and Internalizing Symptomatology in Maltreated and Nonmaltreated Children

    ERIC Educational Resources Information Center

    Kim-Spoon, Jungmeen; Cicchetti, Dante; Rogosch, Fred A.

    2013-01-01

    The longitudinal contributions of emotion regulation and emotion lability-negativity to internalizing symptomatology were examined in a low-income sample (171 maltreated and 151 nonmaltreated children, from age 7 to 10 years). Latent difference score models indicated that for both maltreated and nonmaltreated children, emotion regulation was a…

  18. Effects of neuroprotector cortexin on the dynamics of neuroendocrine system parameters in patients with organic emotionally labile (asthenic) disorders.

    PubMed

    Levchuk, L A; Ivanova, S A; Semke, V Ya

    2013-05-01

    Addition of neuroprotector Cortexin to standard drug therapy of patients with organic emotionally labile (asthenic) disorders had a great influence on the neuroendocrine system and neurosteroid content: normalization of blood concentration of cortisol, dehydroepiandrosterone sulphate, and thyroid hormones was observed. Clinical improvement was associated with the recovery of organism homeostatic systems.

  19. Oral immunization of mice with attenuated Salmonella enteritidis containing a recombinant plasmid which codes for production of the B subunit of heat-labile Escherichia coli enterotoxin.

    PubMed Central

    Clements, J D; Lyon, F L; Lowe, K L; Farrand, A L; el-Morshidy, S

    1986-01-01

    We used Salmonella enteritidis serotype dublin strain SL1438, a nonreverting, aromatic-dependent, histidine-requiring mutant, as a recipient for a recombinant plasmid coding for production of the nontoxic B subunit of the heat-labile Escherichia coli enterotoxin. The S. enteritidis derivative EL23 produced heat-labile enterotoxin subunit B that was indistinguishable from heat-labile enterotoxin subunit B produced by strains of E. coli or Salmonella typhi harboring the same plasmid. Mice immunized orally with strain EL23 developed progressively increasing mucosal and serum antibody responses to both heat-labile enterotoxin subunit B and to the lipopolysaccharide of the vaccine strain. The mucosal antibody response was shown to be immunoglobulin A specific and to be capable of neutralizing the biological activities of both E. coli heat-labile enterotoxin and cholera enterotoxin in vitro. Images PMID:3527989

  20. 14C as a tracer of labile organic matter in Antarctic benthic food webs

    NASA Astrophysics Data System (ADS)

    Purinton, Brett L.; DeMaster, David J.; Thomas, Carrie J.; Smith, Craig R.

    2008-11-01

    14C measurements were made on surface plankton, particle-trap material, surface sediment, benthic invertebrate gut contents, and body tissue samples to assess the effectiveness of this radioisotope as a tracer of labile organic carbon in Antarctic benthic food webs. Samples were collected on five cruises to the West Antarctic Peninsula (WAP) shelf between November 1999 and March 2001 as part of the Food for Benthos on the ANtarctic Continental-Shelf (FOODBANCS) Project. The 14C contents of the body tissues from a variety of deposit feeders (-126±13 per mil) were substantially enriched relative to the surface sediment (-234±13 per mil) and statistically similar to the organic matter collected in plankton tows (-135±10 per mil), indicating that recently produced marine plankton are the primary source of nutrition for these deposit feeders on the West Antarctic shelf. Selective ingestion was the primary feeding strategy used by echiuran worms and certain holothurians (i.e. Peniagone vignoni) for incorporating labile organic carbon into their tissues as demonstrated by the large differences (105±13 per mil) between surface sediment and gut content 14C activities. In contrast, digestive and/or assimilatory selection was the predominant strategy used by an irregular urchin ( Amphipneustes lorioli) and several other holothurians ( Protelpidia murrayi, Bathyplotes fuscivinculum and the head-down conveyor belt feeder, Molpadia musculus), as demonstrated by large differences (42±7 per mil) between the 14C activities of their foregut or whole-gut organic contents and their body tissues. Despite large fluctuations in carbon export from the euphotic zone, benthic feeding strategies remained essentially constant over the 15-month sampling period. No seasonal variation was evident in either the 14C abundance of the deposit-feeder body tissues, or in the 14C abundance of their gut contents. The mean 14C abundance in the body tissues of the two sub-surface deposit feeders ( A

  1. The effect of controlled floods on decadal-scale changes in channel morphology and fine sediment storage in a debris-fan affected river canyon

    NASA Astrophysics Data System (ADS)

    Mueller, E. R.; Grams, P. E.; Schmidt, J. C.

    2013-12-01

    In 2011, a large magnitude flow release from Flaming Gorge Reservoir resulted in the third highest recorded discharge of the Green River downstream from Flaming Gorge Dam subsequent to its closure in 1963. Following this event, we made measurements of channel geometry, tracer gravel displacement, and sandbar sedimentology at four long-term monitoring reaches within the Canyon of Lodore in Dinosaur National Monument, Colorado. Here we integrate these data with nearly two decades of channel monitoring at these sites, encompassing five controlled floods, and providing a coarse resolution, but coherent, picture of channel response and changes in fine sediment storage in a canyon-bound river. We discuss these results in the context of long-term monitoring of controlled flood response along the Colorado River in Marble and Grand Canyons, Arizona. In Canyon of Lodore, moderate, short-duration controlled floods have had little effect on channel morphology or fine sediment storage. Alternatively, higher magnitude floods approaching the pre-dam mean annual flood, such as in 1999 and 2011, tended to be long duration and scoured fine sediment from the channel bed, in some places up to 5 m, while building eddy sandbars to within a meter of flood stage. This resulted in a net export of sediment from the monitored reaches. Between floods, eddy sand bars erode and the pools fill with fine sediment. We have observed only minor erosion or reworking of gravel bars and channel margin deposits stabilized by vegetation encroachment. The Green River in Canyon of Lodore is a scaled-down version of the Colorado River in debris fan-affected Marble and Grand Canyons. Both rivers now exist in varying degrees of sediment deficit due to upstream reservoirs. Coarse sediment from debris fans and hillslopes limits vertical incision and channel migration, focusing the post-dam geomorphic response to sediment imbalance on fine sediment located in eddy sandbars, pools, and channel margin deposits. In

  2. Fluxes of phytopigments and labile organic matter to the deep ocean in the NE Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Fabiano, M.; Pusceddu, A.; Dell'Anno, A.; Armeni, M.; Vanucci, S.; Lampitt, R. S.; Wolff, G. A.; Danovaro, R.

    Downward fluxes of labile organic matter (phytopigments, proteins and carbohydrates) were measured between September 1996 and August 1998 at three depths 1000 m, 3000 m and 4700 m (c. 100 mab) over the Porcupine Abyssal Plain (PAP, NE Atlantic), to provide detailed information on the biochemical characteristics of organic inputs to the deep sea. Temporal changes in the carbohydrate and protein fluxes were compared to carbohydrate and protein contents of the surficial sediment on the seabed beneath the traps at 4850 m depth. Fluxes of carbohydrate, protein and phytopigments (chlorophylls-a and -b, and phaeophytins-a and -b) displayed strong seasonal variations, but limited interannual variability between the two years of measurement. Fluxes of labile organic matter were characterised by strong pulses which occurred in spring and early summer, suggesting that the deep PAP area experiences relatively predictable patterns of vertical fluxes. No major quantitative differences in organic matter fluxes were observed between traps at different depths, but highest carbohydrate fluxes (time-weighted mean 2.4 mg m -2 d -1) were observed at 4700 m, whereas highest protein fluxes were observed at 1000 m (time-weighted mean 2.1 mg m -2 d -1). Carbohydrate, protein and phytopigment fluxes were correlated significantly, suggesting that settling material was associated with primary organic matter (i.e., phytodetritus) inputs from the photic layer. The contributions of chlorophyll-a and -b, and of phaeophytin-a and -b did not change significantly with increasing depth. Nor did the ratio of total phaeopigments to total chlorophylls did change greatly with depth (0.3-0.4 at both 3000 m and 4700 m depth) suggesting that degradation rates in the sinking particles were low. Protein and carbohydrate concentrations in the sediments at 4850 m depth (collected during 6 cruises between 1996 and 1998) and vertical fluxes at 3000 m depth followed inverse temporal patterns; peak concentrations

  3. Membrane Transport Behavior and the Lability of Chloride on Polyphosphazenes Bearing Bulky Substituents

    SciTech Connect

    Frederick F. Stewart; John R. Klaehn; Christopher J. Orme

    2007-08-01

    Polyphosphazenes are an intriguing class of inorganic polymers where much of their functionality is derived from pendant groups attached to phosphorus. The backbone of the polymer consists of alternating phosphorus and nitrogen atoms where the bonding is conventionally drawn as alternating double and single bonds. Orbital nodes are located at each phosphorus atom resulting in electron delocalization between phosphorus atoms, but not through them. Thus, the polymer backbone has a high degree of flexibility where halogens or other leaving groups can be effectively displaced with nucleophiles. In this paper, the first known example of a polyphosphazene with large quantities of non-labile chloride substituents induced by neighboring group steric effects will be discussed. This example is the result of the substitution of poly[bis-chlorophosphazene] with the sodium salt of 3,5-di-tert-butylphenol where only 60% of the chlorines were displaced. This contrasts with the 100% substitution observed with other phenols (phenol, 4-tert-butylphenol, 3-methylphenol, etc.).

  4. Labile iron pool and ferritin content in developing rat brain gamma-irradiated in utero.

    PubMed

    Robello, Elizabeth; Galatro, Andrea; Puntarulo, Susana

    2009-05-01

    This study was aimed to assess the content of total Fe, Ferritin (Ft) and labile Fe pool (LIP) in developing rat brain exposed in utero to 1 Gy of gamma-irradiation. A significant increase (2.3-fold) in the total Fe content of the fetal rat brain irradiated in utero was observed from 1 to 4h post-irradiation, as compared to the content in non-irradiated brain. Ft was analyzed by immunoblotting. The Ft protein was composed by 20 kDa subunits. According to the analysis of the band density in the Western blot, the Ft content decreased by 77+/-15% 2h after gamma-irradiation, as compared to the values in non-irradiated samples. The effect of gamma-irradiation on the LIP was studied by both electron paramagnetic resonance (EPR) and by a fluorescence technique employing calcein (CA). A reduction on the LIP was detected at 2h post-irradiation, independently of the methodology employed for the assay. Since NO content increased in the same time frame of LIP decreasing, a protective role for NO is suggested in fetal rat brain exposed to gamma-irradiation. The data presented in this work are the first experimental evidence suggesting that, as part of the network of the cellular response to limit irradiation-dependent injury, a complex interaction between Fe and NO could be triggered.

  5. Stabilized liquid membrane device (SLMD) for the passive, integrative sampling of labile metals in water

    USGS Publications Warehouse

    Brumbaugh, W.G.; Petty, J.D.; Huckins, J.N.; Manahan, S.E.

    2002-01-01

    A stabilized liquid membrane device (SLMD) is described for potential use as an in situ, passive, integrative sampler for cadmium (Cd), cobalt (Co), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) in natural waters. The SLMD (patent pending) consists of a 2.5-cm-wide by 15-cm-long strip of low-density polyethylene (LDPE) layflat tubing containing 1 mL of an equal mixture (v/v) of oleic acid (cis-9-octadecenoic acid) and EMO-8Q (7-[4-ethyl-1-methyloctyl]-8-quinolinol). The reagent mixture continuously diffuses to the exterior surface of the LDPE membrane, and provides for sequestration of several divalent metals for up to several weeks. Depending on sampler configuration, concentration factors of several thousand can be realized for these metal ions after just a few days. In addition to in situ deployment, the SLMD may be useful for laboratory determination of labile metal species in grab samples. Methods for minimizing the effects of water flow on the sampling rate are currently under investigation.

  6. Isolation and evolution of labile sulfur allotropes via kinetic encapsulation in interactive porous networks

    PubMed Central

    Kitagawa, Hakuba; Ohtsu, Hiroyoshi; Cruz-Cabeza, Aurora J.; Kawano, Masaki

    2016-01-01

    The isolation and characterization of small sulfur allotropes have long remained unachievable because of their extreme lability. This study reports the first direct observation of disulfur (S2) with X-ray crystallography. Sulfur gas was kinetically trapped and frozen into the pores of two Cu-based porous coordination networks containing interactive iodide sites. Stabilization of S2 was achieved either through physisorption or chemisorption on iodide anions. One of the networks displayed shape selectivity for linear molecules only, therefore S2 was trapped and remained stable within the material at room temperature and higher. In the second network, however, the S2 molecules reacted further to produce bent-S3 species as the temperature was increased. Following the thermal evolution of the S2 species in this network using X-ray diffraction and Raman spectroscopy unveiled the generation of a new reaction intermediate never observed before, the cyclo-tri­sulfur dication (cyclo-S3 2+). It is envisaged that kinetic guest trapping in interactive crystalline porous networks will be a promising method to investigate transient chemical species. PMID:27437110

  7. Labile Zn ions on octacalcium phosphate-derived Zn-containing hydroxyapatite surfaces

    NASA Astrophysics Data System (ADS)

    Honda, Yoshitomo; Anada, Takahisa; Morimoto, Shinji; Suzuki, Osamu

    2013-05-01

    We previously synthesized and characterized zinc-containing octacalcium phosphate (OCP) and its hydrolyzed Ca-deficient hydroxyapatite (HA). In the present report, we attempted to define the state of Zn in the OCP-derived Zn-calcium phosphates (CaPs) in relation to the presence of specific amino acids. Zn-containing OCPs were prepared in solutions that included Zn ions up to a concentration of 3.5 mM, and their hydrolyzates [hydrolyzed (hy)-Zn-CaP] were obtained in hot water. The materials were characterized by x-ray diffraction and scanning electron microscopy. The concentration of Ca and Zn ions at room temperature was determined by analyzing the supernatant after incubating the materials in α-minimal essential medium (α-MEM) and HEPES buffer including cysteine, histidine, lysine, aspartic acid, and glutamic acid. Zn ions were more dissolved in α-MEM than HEPES buffer in the absence of amino acids. The inclusion of the amino acids enhanced Zn dissolution by several hundred fold, even in HEPES buffer. Among the amino acids, both cysteine and histidine enhanced the release of Zn. The effect was particularly remarkable with cysteine even in the presence of the other amino acids tested. These results indicate that Zn ions are present as a surface labile pool, which tends to be preferentially desorbed by cysteine, a ubiquitous molecule present in serum.

  8. Labile male morphology and intraspecific male polymorphism in the Philotrypesis fig wasps.

    PubMed

    Jousselin, Emmanuelle; van Noort, Simon; Greeff, Jaco M

    2004-12-01

    We investigate the evolution of male morphology in the fig wasps belonging to the genus Philotrypesis (Chalcidoidea, Sycorectinae). We first reconstruct the phylogenetic relationships of Philotrypesis associated with African figs using nuclear and mitochondrial DNA. We then determine male morphotypes in the species included in our phylogeny and show that intraspecific polymorphism is common. Most species present two types of males and some species have up to three types. These morphotypes are believed to represent alternative mating tactics: some males show morphological adaptations to fighting, others are winged dispersers and others are small sneakers. Mapping out these variations onto our phylogeny reveals that the combination of morphs changes randomly along the branches of the tree. Both parsimony and likelihood approaches indicate that there has been at least one transition from dimorphism to trimorphism, several gains and losses of the small morph and two independent acquisitions of the winged morph. Using maximum likelihood analyses of character evolution, we estimate transition rates for each morph and show that the evolution of each type of morph are not correlated and that forward and backward transition rates are not significantly different. Our results altogether suggest that male morphology is evolutionary labile, it responds quickly to selection imposed by the mating environment. This study, also suggests that seemingly complex phenotypes, such as winged males, can evolve several times and can even be recreated after having been lost.

  9. Uncaria tomentosa (Willd. ex. Roem. & Schult.) DC. and Eucalyptus globulus Labill. interactions when administered with diazepam.

    PubMed

    Quílez, A M; Saenz, M T; García, M D

    2012-03-01

    The safety of natural drugs is defined by their side effects and toxicity as well as any interactions that may occur if taken together with other drugs. In particular, it is essential to identify synergies, antagonisms and other types of interference with other drugs so that the correct choice can be made from the range of phytomedicines available. The aim of this work was to investigate changes in the pharmacological effect of diazepam (2 mg/kg) on the CNS when administered together with a medicinal plant: Eucalyptus globulus Labill. (eucalyptus 6 mg/kg and 3.25 mg/kg) or Uncaria tomentosa (Willd. ex Roem. & Schult). DC. (cat's claw, 7.14 mg/kg and 3.54 mg/kg). Various different psychopharmacological effects were evaluated through assessing exploratory behavior, muscle relaxation and spontaneous motor activity. Both phytodrugs interacted with the benzodiazepine. Eucalyptus had an inhibitory effect at both doses and could be useful at the highest dose in cases where the desired effect of the depressant is moderate anxiolytic activity without marked muscle relaxation. Cat's claw, at both doses, enhanced the action of diazepam on spontaneous motor activity and, at the lowest dose, exploratory ability. These herbal drugs could be useful for their antiinflammatory activity in musculoskeletal pathologies treated with benzodiazepines.

  10. Labile cochlear tuning in the mustached bat. I. Concomitant shifts in biosonar emission frequency.

    PubMed

    Huffman, R F; Henson, O W

    1993-01-01

    The cochlea of the mustached bat (Pteronotus parnellii) has sharp tuning characteristics and pronounced resonance within a narrow band near the second harmonic, constant frequency (CF2) component of the animal's biosonar signals. That fine frequency discrimination occurs within this narrow band is evident from Doppler-shift compensation, whereby bats in flight lower the frequency of emitted CF2s to maintain returning echoes within this band. This study examined various factors capable of producing shifts in both the cochlear resonance frequency (CRF) and CF2s emitted by stationary bats and bats actively Doppler-shift compensating on a pendulum. Each of three experimental factors shifted the CRF in a reversible manner. Changes in body temperature produced an average CRF shift of 39 +/- 18 Hz/degrees C. The CRF increased with flight by 150 +/- 100 Hz and returned to baseline values within 10 min after flight. Contralateral sound exposure produced smaller (100 +/- 20 Hz), rapid shifts in the CRF, suggesting that a mechanism different from the temperature- and flight-related shifts was involved. Changes in the CRF induced by temperature and flight were accompanied by shifts in the emitted CF2 of stationary and moving bats. Coupled with a companion study of associated shifts in neural tuning, the concomitant changes in CRF and CF2 provide evidence of cochlear tuning lability in the mustached bat.

  11. Soft antimicrobial agents: synthesis and activity of labile environmentally friendly long chain quaternary ammonium compounds.

    PubMed

    Thorsteinsson, Thorsteinn; Másson, Már; Kristinsson, Karl G; Hjálmarsdóttir, Martha A; Hilmarsson, Hilmar; Loftsson, Thorsteinn

    2003-09-11

    A series of soft quaternary ammonium antimicrobial agents, which are analogues to currently used quaternary ammonium preservatives such as cetyl pyridinium chloride and benzalkonium chloride, were synthesized. These soft analogues consist of long alkyl chain connected to a polar headgroup via chemically labile spacer group. They are characterized by facile nonenzymatic and enzymatic degradation to form their original nontoxic building blocks. However, their chemical stability has to be adequate in order for them to have antimicrobial effects. Stability studies and antibacterial and antiviral activity measurements revealed relationship between activity, lipophilicity, and stability. Their minimum inhibitory concentration (MIC) was as low as 1 microg/mL, and their viral reduction was in some cases greater than 6.7 log. The structure-activity studies demonstrate that the bioactive compounds (i.e., MIC for Gram-positive bacteria of <10 microg/mL) have an alkyl chain length between 12 and 18 carbon atoms, with a polar headgroup preferably of a small quaternary ammonium group, and their acquired inactivation half-life must be greater than 3 h at 60 degrees C.

  12. An intermetallic Au24Ag20 superatom nanocluster stabilized by labile ligands.

    PubMed

    Wang, Yu; Su, Haifeng; Xu, Chaofa; Li, Gang; Gell, Lars; Lin, Shuichao; Tang, Zichao; Häkkinen, Hannu; Zheng, Nanfeng

    2015-04-08

    An intermetallic nanocluster containing 44 metal atoms, Au24Ag20(2-SPy)4(PhC≡C)20Cl2, was successfully synthesized and structurally characterized by single-crystal analysis and density funtional theory computations. The 44 metal atoms in the cluster are arranged as a concentric three-shell Au12@Ag20@Au12 Keplerate structure having a high symmetry. For the first time, the co-presence of three different types of anionic ligands (i.e., phenylalkynyl, 2-pyridylthiolate, and chloride) was revealed on the surface of metal nanoclusters. Similar to thiolates, alkynyls bind linearly to surface Au atoms using their σ-bonds, leading to the formation of two types of surface staple units (PhC≡C-Au-L, L = PhC≡C(-) or 2-pyridylthiolate) on the cluster. The co-presence of three different surface ligands allows the site-specific surface and functional modification of the cluster. The lability of PhC≡C(-) ligands on the cluster was demonstrated, making it possible to keep the metal core intact while removing partial surface capping. Moreover, it was found that ligand exchange on the cluster occurs easily to offer various derivatives with the same metal core but different surface functionality and thus different solubility.

  13. Effects of physical constraints on the lability of POM during summer in the Ross Sea

    NASA Astrophysics Data System (ADS)

    Misic, Cristina; Covazzi Harriague, Anabella; Mangoni, Olga; Aulicino, Giuseppe; Castagno, Pasquale; Cotroneo, Yuri

    2017-02-01

    The 0-200 m surface layer of the Ross Sea was studied during summer 2014 to investigate the lability of the particulate organic matter (POM) in response to physical parameters. With the use of satellite information, we selected three zones, characterised by different physical setting: a northern offshore area, crossing the summer-polynya area of the Ross Sea (hereafter called ROME 1), a more coastal area next to the Terra Nova Bay polynya (ROME 2); a southern offshore area, towards the Ross Ice Shelf (ROME 3). Ice-maps showed that the seasonal ice retreat had already occurred in early December for most of the stations. Statistical analysis of the quantitative and qualitative characteristics of the POM pointed to significant differences between the stations, especially in the upper mixed layer (UML). A comparison with previous studies showed that the localised pulses of POM accumulation in the UML were similar to those recorded at the highly productive marginal ice zones, providing notable trophic support to the ecosystem. The UML, although rather thin and easily subjected to alterations, confirmed its pivotal role in the ecosystem dynamics. A POM quality favourable to consumers was highlighted at several stations in ROME 1 and ROME 3. Reduced trophic support was, instead, found in ROME 2. Limited POM consumption where deep-water formation takes place would increase the POM role in the transfer of C to the depths.

  14. Facile synthesis of acid-labile polymers with pendent ortho esters.

    PubMed

    Cheng, Jing; Ji, Ran; Gao, Shi-Juan; Du, Fu-Sheng; Li, Zi-Chen

    2012-01-09

    This work presents a facile approach for preparation of acid-labile and biocompatible polymers with pendent cyclic ortho esters, which is based on the efficient and mild reactions between cyclic ketene acetal (CKA) and hydroxyl groups. Three CKAs, 2-ethylidene-1,3-dioxane (EDO), 2-ethylidene-1,3-dioxolane (EDL), and 2-ethylidene-4- methyl-1,3-dioxolane (EMD) were prepared from the corresponding cyclic vinyl acetals by catalytic isomerization of the double bond. The reaction of CKAs with different alcohols and diols was examined using trace of p-toluenesulfonic acid as a catalyst. For the monohydroxyl alcohols, cyclic ortho esters were formed by simple addition of the hydroxyl group toward CKAs with ethanol showing a much greater reactivity than iso-propanol. When 1,2- or 1,3-diols were used to react with the CKAs, we observed the isomerized cyclic ortho esters besides the simple addition products. Biocompatible polyols, that is, poly(2-hydroxyethyl acrylate) (PHEA) and poly(vinyl alcohol) (PVA) were then modified with CKAs, and the degree of substitution of the pendent ortho esters can be easily tuned by changing feed ratio. Both the small molecule ortho esters and the CKA-modified polymers demonstrate the pH-dependent hydrolysis profiles, which depend also on the chemical structure of the ortho esters as well as the polymer hydrophobicity.

  15. Protein kinase C-δ isoform mediates lysosome labilization in DNA damage-induced apoptosis

    PubMed Central

    PARENT, NICOLAS; SCHERER, MAX; LIEBISCH, GERHARD; SCHMITZ, GERD; BERTRAND, RICHARD

    2013-01-01

    A lysosomal pathway, characterized by the partial rupture or labilization of lysosomal membranes (LLM) and cathepsin release into the cytosol, is evoked during the early events of 20-S-camptothecin lactone (CPT)-induced apoptosis in human cancer cells, including human histiocytic lymphoma U-937 cells. These lysosomal events begin rapidly and simultaneously with mitochondrial permeabilization and caspase activation within 3 h after drug treatment. Recently, in a comparative proteomics analysis performed on highly-enriched lysosomal extracts, we identified proteins whose translocation to lysosomes correlated with LLM induction after CPT treatment, including protein kinase C-δ (PKC-δ). In this study, we show that the PKC-δ translocation to lysosomes is required for LLM, as silencing its expression with RNA interference or suppressing its activity with the inhibitor, rottlerin, prevents CPT-induced LLM. PKC-δ translocation to lysosomes is associated with lysosomal acidic sphingomyelinase (ASM) phosphorylation and activation, which in turn leads to an increase in ceramide (CER) content in lysosomes. The accumulation of endogenous CER in lysosomes is a critical event for CPT-induced LLM as suppressing PKC-δ or ASM activity reduces both the CPT-mediated CER generation in lysosomes and CPT-induced LLM. These findings reveal a novel mechanism by which PKC-δ mediates ASM phosphorylation/activation and CER accumulation in lysosomes in CPT-induced LLM, rapidly activating the lysosomal pathway of apoptosis after CPT treatment. PMID:21174057

  16. Expression of Escherichia coli heat-labile enterotoxin B subunit (LTB) in Saccharomyces cerevisiae.

    PubMed

    Rezaee, Mohammad Ahangarz; Rezaee, Abbas; Moazzeni, Seyed Mohammad; Salmanian, Ali Hatef; Yasuda, Yoko; Tochikubo, Kunio; Pirayeh, Shahin Najar; Arzanlou, Mohsen

    2005-08-01

    Heat-labile enterotoxin B subunit (LTB) of enterotoxigenic Escherichia coli (ETEC) is both a strong mucosal adjuvant and immunogen. It is a subunit vaccine candidate to be used against ETEC-induced diarrhea. It has already been expressed in several bacterial and plant systems. In order to construct yeast expressing vector for the LTB protein, the eltB gene encoding LTB was amplified from a human origin enterotoxigenic E. coli DNA by PCR. The expression plasmid pLTB83 was constructed by inserting the eltB gene into the pYES2 shuttle vector immediately downstream of the GAL1 promoter. The recombinant vector was transformed into S. cerevisiae and was then induced by galactose. The LTB protein was detected in the total soluble protein of the yeast by SDS-PAGE analysis. Quantitative ELISA showed that the maximum amount of LTB protein expressed in the yeast was approximately 1.9% of the total soluble protein. Immunoblotting analysis showed the yeast-derived LTB protein was antigenically indistinguishable from bacterial LTB protein. Since the whole-recombinant yeast has been introduced as a new vaccine formulation the expression of LTB in S. cerevisiae can offer an inexpensive yet effective strategy to protect against ETEC, especially in developing countries where it is needed most.

  17. Development and bioorthogonal activation of palladium-labile prodrugs of gemcitabine.

    PubMed

    Weiss, Jason T; Dawson, John C; Fraser, Craig; Rybski, Witold; Torres-Sánchez, Carmen; Bradley, Mark; Patton, E Elizabeth; Carragher, Neil O; Unciti-Broceta, Asier

    2014-06-26

    Bioorthogonal chemistry has become one of the main driving forces in current chemical biology, inspiring the search for novel biocompatible chemospecific reactions for the past decade. Alongside the well-established labeling strategies that originated the bioorthogonal paradigm, we have recently proposed the use of heterogeneous palladium chemistry and bioorthogonal Pd(0)-labile prodrugs to develop spatially targeted therapies. Herein, we report the generation of biologically inert precursors of cytotoxic gemcitabine by introducing Pd(0)-cleavable groups in positions that are mechanistically relevant for gemcitabine's pharmacological activity. Cell viability studies in pancreatic cancer cells showed that carbamate functionalization of the 4-amino group of gemcitabine significantly reduced (>23-fold) the prodrugs' cytotoxicity. The N-propargyloxycarbonyl (N-Poc) promoiety displayed the highest sensitivity to heterogeneous palladium catalysis under biocompatible conditions, with a reaction half-life of less than 6 h. Zebrafish studies with allyl, propargyl, and benzyl carbamate-protected rhodamines confirmed N-Poc as the most suitable masking group for implementing in vivo bioorthogonal organometallic chemistry.

  18. Antimicrobial activity of globulol isolated from the fruits of Eucalyptus globulus Labill.

    PubMed

    Tan, Manliang; Zhou, Ligang; Huang, Yongfu; Wang, Ye; Hao, Xiaojiang; Wang, Jingguo

    2008-05-10

    An antimicrobial sesquiterpene was separated by bioassay-guided isolation from the petroleum ether fraction of the ethanol crude extract of Eucalyptus globulus Labill (Myrtaceae) fruits, and was identified as globulol by physicochemical properties and spectroscopic analysis. Mycelial growth method revealed that the median effective inhibitory concentration (IC50) values of globulol on Alternaria solani, Fusarium oxysporum f.sp. niverum, F. graminearum, Rhizoctonia solani and Venturia pirina were 47.1 microg mL(-1), 114.3 microg mL(-1), 53.4 microg mL(-1), 56.9 microg mL(-1), 32.1 microg mL(-1) and 21.8 microg mL(-1), respectively. MTT-colorimetric assay revealed that IC50 values of globulol on Xanthomonas vesicatoria and Bacillus subtilis were 158.0 microg mL(-1) and 737.2 microg mL(-1), respectively. The results indicated that globulol could be a main antimicrobial compound in the ethanol crude extract of E. globulus fruits.

  19. Diffusive gradients in thin films measurement of sulfur stable isotope variations in labile soil sulfate.

    PubMed

    Hanousek, Ondrej; Santner, Jakob; Mason, Sean; Berger, Torsten W; Wenzel, Walter W; Prohaska, Thomas

    2016-11-01

    A diffusive gradient in thin films (DGT) technique, based on a strongly basic anion exchange resin (Amberlite IRA-400), was successfully tested for (34)S/(32)S analysis in labile soil sulfate. Separation of matrix elements (Na, K, and Ca) that potentially cause non-spectral interferences in (34)S/(32)S analysis by MC ICP-MS (multi-collector inductively coupled plasma-mass spectrometry) during sampling of sulfate was demonstrated. No isotopic fractionation caused by diffusion or elution of sulfate was observed below a resin gel disc loading of ≤79 μg S. Above this threshold, fractionation towards (34)S was observed. The method was applied to 11 different topsoils and one mineral soil profile (0-100 cm depth) and compared with soil sulfate extraction by water. The S amount and isotopic ratio in DGT-S and water-extractable sulfate correlated significantly (r (2) = 0.89 and r (2) = 0.74 for the 11 topsoils, respectively). The systematically lower (34)S/(32)S isotope ratios of the DGT-S were ascribed to mineralization of organic S.

  20. Facile Generation of Tumor-pH-Labile Linkage-Bridged Block Copolymers for Chemotherapeutic Delivery.

    PubMed

    Sun, Chun-Yang; Liu, Yang; Du, Jin-Zhi; Cao, Zhi-Ting; Xu, Cong-Fei; Wang, Jun

    2016-01-18

    Successful bench-to-bedside translation of nanomedicine relies heavily on the development of nanocarriers with superior therapeutic efficacy and high biocompatibility. However, the optimal strategy for improving one aspect often conflicts with the other. Herein, we report a tactic of designing tumor-pH-labile linkage-bridged copolymers of clinically validated poly(D,L-lactide) and poly(ethylene glycol) (PEG-Dlink(m)-PDLLA) for safe and effective drug delivery. Upon arriving at the tumor site, PEG-Dlink(m)-PDLLA nanoparticles will lose the PEG layer and increase zeta potential by responding to tumor acidity, which significantly enhances cellular uptake and improves the in vivo tumor inhibition rate to 78.1% in comparison to 47.8% of the non-responsive control. Furthermore, PEG-Dlink(m)-PDLLA nanoparticles show comparable biocompatibility with the clinically used PEG-b-PDLLA micelle. The improved therapeutic efficacy and safety demonstrate great promise for our strategy in future translational studies.

  1. Effect of pH on Metal Lability in Drinking Water Treatment Residuals.

    PubMed

    Wang, Changhui; Yuan, Nannan; Pei, Yuansheng

    2014-01-01

    Drinking water treatment residuals (WTRs), by-products generated during treatment of drinking water, can be reused as environmental amendments to remediate contamination. However, this beneficial reuse may be hampered by the potential release of toxic contaminants (e.g., metals) in the WTRs. In present study, batch tests and then fractionation, in vitro digestion, and the toxicity characteristic leaching procedure were used to investigate the release and extractability of metals in the Fe/Al hydroxides comprised WTRs under differing pH. The results demonstrated that significant release from WTRs for Ba, Be, Ca, Cd, Co, Cr, Fe, Mg, Mn, Pb, Sr, and Zn occurred under low pH (acid condition); for As, Mo, and V under high pH (alkaline condition); and for Al, Cu, and Ni under both conditions. In comparison, most metals in the WTRs were more easily released under low pH, but the release was stable at a relatively low level between pH 6 and 9, especially under alkaline conditions. Further analysis indicated that the chemical extractability and bioaccessibility of many metals was found to increase in the WTRs after being leached, even though the leached WTRs could still be considered nonhazardous. These results demonstrated that pH had a substantial effect on the lability of metals in WTRs. Overall, caution should be used when considering pH conditions during WTRs reuse to avoid potential metal pollution.

  2. Inhibition of Escherichia coli heat-labile enterotoxin-induced diarrhea by Chaenomeles speciosa.

    PubMed

    Chen, Jaw-Chyun; Chang, Yuan-Shiun; Wu, Shih-Lu; Chao, De-Cheng; Chang, Chih-Shiang; Li, Chia-Cheng; Ho, Tin-Yun; Hsiang, Chien-Yun

    2007-09-05

    Enterotoxigenic Escherichia coli (ETEC) is responsible for millions of deaths in developing countries. Heat-labile enterotoxin (LT), the virulence factor of ETEC, induces diarrhea by initially binding to the G(M1) on the surface of intestinal epithelial cells and consequently leading to the massive loss of fluid and ions from cells. Fruit of Chaenomeles (FC), the dried fruit of Chaenomeles speciosa, has been used for diarrhea in China. However, the anti-diarrheal mechanism of FC is still unclear. In this study, we demonstrated that FC extract (FCE) inhibited the LT-induced diarrhea in mice by blocking the binding of the B subunit of LT (LTB) to G(M1). The ethyl acetate (EA) soluble fraction was the most active fraction of FC that significantly abolished the LTB and G(M1) interaction. Furthermore, the oleanolic acid, ursolic acid, and betulinic acid from EA fraction, blocked the toxin binding effects, resulting in the suppression of LT-induced diarrhea. Moreover, by docking techniques, these compounds fitted LTB well via hydrogen bonds and hydrophobic contacts with amino acid residues of LTB. In conclusion, our findings suggested that oleanolic acid, ursolic acid, and betulinic acid were the active constituents from FC and might be considered as lead therapeutic agents in the treatment of LT-induced diarrhea.

  3. Determination of labile copper, cobalt, and chromium in textile mill wastewater

    SciTech Connect

    Crain, J.S.; Essling, A.M.; Kiely, J.T.

    1997-01-01

    Copper, chromium, and cobalt species present in filtered wastewater effluent were separated by cation exchange and reverse phase chromatography. Three sample fractions were obtained: one containing metal cations (i.e., trivalent Cr, divalent Cu, and divalent Co), one containing organic species (including metallized dyes), and one containing other unretained species. The metal content of each fraction was determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The sum of the corrected data was compared to the metal content of a filtered effluent aliquot digested totally with fuming sulfuric acid. Other aliquots of the filtered effluent were spiked with the metals of interest and digested to confirm chemical yield and accuracy. Method detection limits were consistently below 20 {mu}g L{sup -1} for Cu, 30 {mu}g L{sup -1} for Co, and 10 {mu}g L{sup -1} for Cr. Spike recoveries for undifferentiated Cu and Cr were statistically indistinguishable from unity; although Co spike recoveries were slightly low ({approximately}95%), its chemical yield was 98%. Copper retention on the sodium sulfonate cation exchange resin was closely correlated with the [EDTA]/[Cu] ratio, suggesting that metals retained upon the cation exchange column were assignable to labile metal species; however, mass balances for all three elements, though reasonable ({approximately}90%), were significantly different from unity. Mechanical factors may have contributed to the material loss, but other data suggest that some metal species reacted irreversibly with the reverse phase column. 3 refs., 2 figs., 4 tabs.

  4. DGT-labile As, Cd, Cu and Ni monitoring in freshwater: toward a framework for interpretation of in situ deployment.

    PubMed

    Buzier, Rémy; Charriau, Adeline; Corona, David; Lenain, Jean-François; Fondanèche, Patrice; Joussein, Emmanuel; Poulier, Gaëlle; Lissalde, Sophie; Mazzella, Nicolas; Guibaud, Gilles

    2014-09-01

    The use of the Diffusive Gradient in Thin Film sampler (DGT) as a monitoring tool for regulatory programs is currently evaluated. In this context, the impact of commonly followed procedures on the accuracy of DGT-labile As, Cd, Cu, and Ni quantification was studied. Initial sampler contamination yields to define quantification limits instead of using blank subtraction, thus avoiding artifact concentrations. Not considering the alteration of element diffusion by the filter membrane leads to significant underestimation. However, diffusion coefficients determined on a non-fouled membrane were found to be suitable for the studied site, making it possible to use data from the literature. When diffusive boundary layer formation is neglected, no loss of accuracy is recorded provided the layer is thinner than 0.5 mm. Finally, exploration of potential biases allowed initiating a framework that might help limit inaccuracies in DGT-labile concentration estimation and interpretation, especially in a low contamination context.

  5. Dual, differential isotope labeling shows the preferential movement of labile plant constituents into mineral-bonded soil organic matter.

    PubMed

    Haddix, Michelle L; Paul, Eldor A; Cotrufo, M Francesca

    2016-06-01

    The formation and stabilization of soil organic matter (SOM) are major concerns in the context of global change for carbon sequestration and soil health. It is presently believed that lignin is not selectively preserved in soil and that chemically labile compounds bonding to minerals comprise a large fraction of the SOM. Labile plant inputs have been suggested to be the main precursor of the mineral-bonded SOM. Litter decomposition and SOM formation are expected to have temperature sensitivity varying with the lability of plant inputs. We tested this framework using dual (13) C and (15) N differentially labeled plant material to distinguish the metabolic and structural components within a single plant material. Big Bluestem (Andropogon gerardii) seedlings were grown in an enriched (13) C and (15) N environment and then prior to harvest, removed from the enriched environment and allowed to incorporate natural abundance (13) C-CO2 and (15) N fertilizer into the metabolic plant components. This enabled us to achieve a greater than one atom % difference in (13) C between the metabolic and structural components within the plant litter. This differentially labeled litter was incubated in soil at 15 and 35 °C, for 386 days with CO2 measured throughout the incubation. After 14, 28, 147, and 386 days of incubation, the soil was subsequently fractionated. There was no difference in temperature sensitivity of the metabolic and structural components with regard to how much was respired or in the amount of litter biomass stabilized. Only the metabolic litter component was found in the sand, silt, or clay fraction while the structural component was exclusively found in the light fraction. These results support the stabilization framework that labile plant components are the main precursor of mineral-associated organic matter.

  6. Molecular Imaging of Labile Iron(II) Pools in Living Cells with a Turn-On Fluorescent Probe

    PubMed Central

    Au-Yeung, Ho Yu; Chan, Jefferson; Chantarojsiri, Teera; Chang, Christopher J.

    2013-01-01

    Iron is an essential metal for living organisms, but misregulation of its homeostasis at the cellular level can trigger detrimental oxidative and/or nitrosative stress and damage events. Motivated to help study the physiological and pathological consequences of biological iron regulation, we now report a reaction-based strategy for monitoring labile Fe2+ pools in aqueous solution and in living cells. Iron Probe 1 (IP1) exploits a bioinspired, iron-mediated oxidative C–O bond cleavage reaction to achieve a selective turn-on response to Fe2+ over a range of cellular metal ions in their bioavailable forms. We show that this first-generation chemical tool for fluorescence Fe2+ detection can visualize changes in exchangeable iron stores in living cells upon iron supplementation or depletion, including labile iron pools at endogenous, basal levels. Moreover, IP1 can be used to identify reversible expansion of labile iron pools by stimulation with vitamin C or the iron regulatory hormone hepcidin, providing a starting point for further investigations of iron signaling and stress events in living systems as well as future probe development. PMID:24063668

  7. On-demand combinational delivery of curcumin and doxorubicin via a pH-labile micellar nanocarrier.

    PubMed

    Li, Haoyu; Li, Man; Chen, Chao; Fan, Aiping; Kong, Deling; Wang, Zheng; Zhao, Yanjun

    2015-11-10

    The combinational delivery of doxorubicin and curcumin in a physically loaded nanocarrier offers the benefits of enhanced therapeutic efficacy and reduced adverse effects, but this strategy often suffers from the slow drug release followed by delayed onset of pharmacological action. This work reported the hydrazone-linked polymer-curcumin conjugate micelles containing physically loaded doxorubicin to address this problem; the ester-linked conjugate micelles were produced as the control. The pH-labile spherical micelles were less than 100 nm with a loading at 9.3 ± 0.5% (w/w, Curcumin) and 2.5 ± 0.1(w/w, Doxorubicin). Both agents were released at a faster rate in the pH-labile micelles compared to the control. The confocal laser scanning microscopy revealed a time-dependent co-localization of both agents in HepG2 cells. The IC50 of pH-labile conjugate micelles without doxorubicin in HepG2 cells was 27.7 ± 5.3 (μM), whereas the co-loaded micelles was lowered to 10.8 ± 3.4 (μM) (Cur-equivalent dose). The combination index calculation demonstrated a synergistic action of both agents in the co-loading nanocarrier. The current work provided an efficient nanocarrier system to achieve rapid on-demand drug release without onset delay of therapeutic action, which might add value to the clinical translation of the combinational delivery systems.

  8. Visualization of Peroxynitrite-Induced Changes of Labile Zn2+ in the Endoplasmic Reticulum with Benzoresorufin-based Fluorescent Probes

    PubMed Central

    Lin, Wei; Buccella, Daniela; Lippard, Stephen J.

    2013-01-01

    Zn2+ plays essential roles in biology, and the homeostasis of Zn2+ is tightly regulated in all cells. Subcellular distribution and trafficking of labile Zn2+, and its interrelation with reactive nitrogen species, are poorly understood due to the scarcity of appropriate imaging tools. We report a new family of red-emitting fluorescent sensors for labile Zn2+, ZBR1-3, based on a benzoresorufin platform functionalized with dipicolylamine or picolylamine-derived metal binding groups. In combination, the pendant amines and fluorophore afford an [N3O] binding motif that resembles that of previously reported fluorescein-based sensors of the Zinpyr family, reproducing well their binding capabilities and yielding comparable Kd values in the subnanomolar and picomolar range. The ZBR sensors display up to 8.4-fold emission fluorescence enhancement upon Zn2+ binding in the cuvette, with similar responses obtained in live cells using standard wide-field fluorescence microscopy imaging. The new sensors localize spontaneously in the endoplasmic reticulum (ER) of various tested cell lines, allowing for organelle-specific monitoring of zinc levels in live cells. Study of ER zinc levels in neural stem cells (NSC) treated with a peroxynitrite generator, Sin-1, revealed an immediate decrease in labile Zn2+ thus providing evidence for a direct connection between ER stress and ER Zn2+ homeostasis. PMID:23902285

  9. Measurement of labile Cu in soil using stable isotope dilution and isotope ratio analysis by ICP-MS.

    PubMed

    Nolan, Annette L; Ma, Yibing; Lombi, Enzo; McLaughlin, Mike J

    2004-11-01

    Isotope dilution is a useful technique to measure the labile metal pool, which is the amount of metal in soil in rapid equilibrium (<7 days) with the soil solution. This is normally performed by equilibrating soil with a metal isotope, and sampling the labile metal pool by using an extraction (E value), or by growing plants (L value). For Cu, this procedure is problematic for E values, and impossible for L values, due to the short half-life of the 64Cu radioisotope (12.4 h), which makes access and handling very difficult. We therefore developed a technique using enriched 65Cu stable isotope and measurement of 63Cu/65Cu ratios by quadrupole inductively coupled plasma mass spectrometry (ICP-MS) to measure labile pools of Cu in soils using E value techniques. Mass spectral interferences in detection of 63Cu/65Cu ratios in soil extracts were found to be minimal. Isotope ratios determined by quadrupole ICP-MS compared well to those determined by high-resolution (magnetic sector) ICP-MS. E values determined using the stable isotope technique compared well to those determined using the radioisotope for both uncontaminated and Cu-contaminated soils.

  10. CD44 Binding to Hyaluronic Acid Is Redox Regulated by a Labile Disulfide Bond in the Hyaluronic Acid Binding Site

    PubMed Central

    Kellett-Clarke, Helena; Stegmann, Monika; Barclay, A. Neil; Metcalfe, Clive

    2015-01-01

    CD44 is the primary leukocyte cell surface receptor for hyaluronic acid (HA), a component of the extracellular matrix. Enzymatic post translational cleavage of labile disulfide bonds is a mechanism by which proteins are structurally regulated by imparting an allosteric change and altering activity. We have identified one such disulfide bond in CD44 formed by Cys77 and Cys97 that stabilises the HA binding groove. This bond is labile on the surface of leukocytes treated with chemical and enzymatic reducing agents. Analysis of CD44 crystal structures reveal the disulfide bond to be solvent accessible and in the–LH hook configuration characteristic of labile disulfide bonds. Kinetic trapping and binding experiments on CD44-Fc chimeric proteins show the bond is preferentially reduced over the other disulfide bonds in CD44 and reduction inhibits the CD44-HA interaction. Furthermore cells transfected with CD44 no longer adhere to HA coated surfaces after pre-treatment with reducing agents. The implications of CD44 redox regulation are discussed in the context of immune function, disease and therapeutic strategies. PMID:26379032

  11. The distance of visual targets affects the spatial magnitude and multifractal scaling of standing body sway in younger and older adults.

    PubMed

    Munafo, Justin; Curry, Christopher; Wade, Michael G; Stoffregen, Thomas A

    2016-09-01

    The spatial magnitude of standing body sway is greater during viewing of more distant targets and reduced when viewing nearby targets. Classical interpretations of this effect are based on the projective geometry of changes in visual stimulation that are brought about by body sway. Such explanations do not motivate predictions about the temporal dynamics of body sway. We asked whether the distance of visible targets would affect both the spatial magnitude and the multifractality of standing body sway. It has been suggested that the multifractality of movement may change with age. Separately, previous research has not addressed the effects of target distance on postural sway in older adults. For these reasons, we crossed our variation in target distance with variation in age. In an open-air setting, we measured standing body sway in younger and older adults while looking at visual targets that were placed at three distances. The distance of visual targets affected the spatial magnitude of body sway in younger adults, replicating past studies. Target distance also affected the spatial magnitude of sway in older adults, confirming that this relation persists despite other age-related changes. Target distance also affected the multifractality of body sway, but this effect was modulated by age. Finally, the width of the multifractal spectrum was greater for older adults than for younger adults, revealing that healthy aging can affect the multifractality of movement. These findings reveal similarities and differences between the spatial magnitude and the multifractality of human movement.

  12. Alkali-labile sites in sperm cells from Sus and Ovis species.

    PubMed

    Cortés-Gutiérrez, Elva I; Dávila-Rodríguez, Martha I; López-Fernández, Carmen; Fernández, José Luis; Gosálvez, Jaime

    2008-06-01

    Constitutive alkali-labile sites (ALSs) have been investigated using a protocol of DNA breakage detection-fluorescence in situ hybridization (DBD-FISH) in sperm cells from Sus domesticus (pig), Ovis gmelini musimon (mouflon) and Ovis aries (sheep). The results were compared with those obtained using leucocytes from the same species. Whole comparative genomic hybridization (W-CGH) showed that most of the constitutive ALSs in somatic and germ line cells in all species examined were constrained to particular repetitive satellite DNA sequences located in the pericentromeric constitutive heterochromatin of each chromosome. However, their relative abundance was different among cells of the same organism (leucocytes/sperm cells), and this trend was not maintained when the different species were compared. Thus, in mouflon, the density of ALSs in leucocytes when compared with that observed in sperm cells indicated abundance of the order of eight times less. In sheep, both leucocytes and sperm cells exhibited a large quantity of ALSs, being of the order of four times more abundant in sperm cells. In the pig genome, leucocytes showed a high abundance of ALSs (of the order of 12 times more that in sperm cells) but only involved the metacentric chromosomes of the karyotype. ALSs were not present in the acrocentric chromosomes. Contrary to mouflon and sheep, ALSs were relatively scarce in sperm cells from pig. These results suggest that ALSs are a transient structural feature in the cells of any organisms and point to a non-universal model of chromatin organization in sperm cells among mammals.

  13. A thermally responsive injectable hydrogel incorporating methacrylate-polylactide for hydrolytic lability

    PubMed Central

    Ma, Zuwei; Nelson, Devin M.; Hong, Yi; Wagner, William R.

    2011-01-01

    Injectable thermoresponsive hydrogels are of interest for a variety of biomedical applications, including regional tissue mechanical support as well as drug and cell delivery. Within this class of materials there is a need to provide options for gels with stronger mechanical properties as well as variable degradation profiles. To address this need, the hydrolytically labile monomer, methacrylate-polylactide (MAPLA), with an average 2.8 lactic acid units, was synthesized and copolymerized with N-isopropylacrylamide (NIPAAm) and 2-hydroxyethyl methacrylate (HEMA) to obtain bioabsorbable thermally responsive hydrogels. Poly(NIPAAm-co-HEMA-co-MAPLA) with three monomer feed ratios (84/10/6, 82/10/8 and 80/10/10) was synthesized and characterized with NMR, FTIR and GPC. The copolymers were soluble in saline at reduced temperature (<10°C), forming clear solutions that increased in viscosity with the MAPLA feed ratio. The copolymers underwent sol-gel transition at lower critical solution temperatures of 12.4, 14.0 and 16.2°C respectively and solidified immediately upon being placed in a 37°C water bath. The warmed hydrogels gradually excluded water to reach final water contents of ~45%. The hydrogels as formed were mechanically strong, with tensile strengths as high as 100 kPa and shear moduli of 60 kPa. All three hydrogels were completely degraded (solubilized) in PBS over a 6–8 month period at 37°C, with a higher MAPLA feed ratio resulting in a faster degradation period. Culture of primary vascular smooth muscle cells with degradation solutions demonstrated a lack of cytotoxicity. The synthesized hydrogels provide new options for biomaterial injection therapy where increased mechanical strength and relatively slow resorption rates would be attractive. PMID:20575552

  14. Temperature-dependent shift from labile to recalcitrant carbon sources of arctic heterotrophs.

    PubMed

    Biasi, Christina; Rusalimova, Olga; Meyer, Hildegard; Kaiser, Christina; Wanek, Wolfgang; Barsukov, Pavel; Junger, Högne; Richter, Andreas

    2005-01-01

    Soils of high latitudes store approximately one-third of the global soil carbon pool. Decomposition of soil organic matter (SOM) is expected to increase in response to global warming, which is most pronounced in northern latitudes. It is, however, unclear if microorganisms are able to utilize more stable, recalcitrant C pools, when labile soil carbon pools will be depleted due to increasing temperatures. Here we report on an incubation experiment with intact soil cores of a frost-boil tundra ecosystem at three different temperatures (2 degrees C, 12 degrees C and 24 degrees C). In order to assess which fractions of the SOM are available for decomposition at various temperatures, we analyzed the isotopic signature of respired CO2 and of different SOM fractions. The delta13C values of CO2 respired were negatively correlated with temperature, indicating the utilization of SOM fractions that were depleted in 13C at higher temperatures. Chemical fractionation of SOM showed that the water-soluble fraction (presumably the most easily available substrates for microbial respiration) was most enriched in 13C, while the acid-insoluble pool (recalcitrant substrates) was most depleted in 13C. Our results therefore suggest that, at higher temperatures, recalcitrant compounds are preferentially respired by arctic microbes. When the isotopic signatures of respired CO2 of soils which had been incubated at 24 degrees C were measured at 12 degrees C, the delta13C values shifted to values found in soils incubated at 12 degrees C, indicating the reversible use of more easily available substrates. Analysis of phospholipid fatty acid profiles showed significant differences in microbial community structure at various incubation temperatures indicating that microorganisms with preference for more recalcitrant compounds establish as temperatures increase. In summary our results demonstrate that a large portion of tundra SOM is potentially mineralizable.

  15. Rainfall and labile carbon availability control litter nitrogen dynamics in a tropical dry forest.

    PubMed

    Anaya, Carlos A; García-Oliva, Felipe; Jaramillo, Víctor J

    2007-01-01

    N cycling in tropical dry forests is driven by rainfall seasonality but the mechanisms involved are not well understood. We studied the seasonal variation in N dynamics and microbial biomass in the surface litter of a tropical dry forest ecosystem in Mexico over a 2-year period. Litter was collected at 4 different times of the year to determine changes in total, soluble, and microbial C and N concentrations. Additionally, litter from each sampling date was incubated under laboratory conditions to determine potential C mineralization rate, net N mineralization, net C and N microbial immobilization, and net nitrification. Litter C concentrations were highest in the early-dry season and lowest in the rainy season, while the seasonal changes in N concentrations varied between years. Litter P was higher in the rainy than in the early-dry season. Water-soluble organic C (WSOC) and water-soluble N concentrations were highest during the early- and late-dry seasons and represented up to 4.1 and 5.9% of the total C and N, respectively. NH (4) (+) and NO (3) (-) showed different seasonal and annual variations. They represented an average 23% of soluble N. Microbial C was generally higher in the dry than in the wet seasons, while microbial N was lowest in the late-dry and highest in the early-rainy seasons. Incubations showed that lowest potential C mineralization rates and C and N microbial immobilization occurred in rainy season litter, and were positively correlated to WSOC. Net nitrification was highest in rainy season litter. Our results showed that the seasonal pattern in N dynamics was influenced by rainfall seasonality and labile C availability, and not by microbial biomass. We propose a conceptual model to hypothesize how N dynamics in the litter layer of the Chamela tropical dry forest respond to the seasonal variation in rainfall.

  16. Labile sleep promotes awareness of abstract knowledge in a serial reaction time task.

    PubMed

    Kirov, Roumen; Kolev, Vasil; Verleger, Rolf; Yordanova, Juliana

    2015-01-01

    Sleep has been identified as a critical brain state enhancing the probability of gaining insight into covert task regularities. Both non-rapid eye movement (NREM) and rapid eye movement (REM) sleep have been implicated with offline re-activation and reorganization of memories supporting explicit knowledge generation. According to two-stage models of sleep function, offline processing of information during sleep is sequential requiring multiple cycles of NREM and REM sleep stages. However, the role of overnight dynamic sleep macrostructure for insightfulness has not been studied so far. In the present study, we test the hypothesis that the frequency of interactions between NREM and REM sleep stages might be critical for awareness after sleep. For that aim, the rate of sleep stage transitions was evaluated in 53 participants who learned implicitly a serial reaction time task (SRTT) in which a determined sequence was inserted. The amount of explicit knowledge about the sequence was established by verbal recall after a night of sleep following SRTT learning. Polysomnography was recorded in this night and in a control night before and was analyzed to compare the rate of sleep-stage transitions between participants who did or did not gain awareness of task regularity after sleep. Indeed, individual ability of explicit knowledge generation was strongly associated with increased rate of transitions between NREM and REM sleep stages and between light sleep stages and slow wave sleep. However, the rate of NREM-REM transitions specifically predicted the amount of explicit knowledge after sleep in a trait-dependent way. These results demonstrate that enhanced lability of sleep goes along with individual ability of knowledge awareness. Observations suggest that facilitated dynamic interactions between sleep stages, particularly between NREM and REM sleep stages play a role for offline processing which promotes rule extraction and awareness.

  17. Labile sleep promotes awareness of abstract knowledge in a serial reaction time task

    PubMed Central

    Kirov, Roumen; Kolev, Vasil; Verleger, Rolf; Yordanova, Juliana

    2015-01-01

    Sleep has been identified as a critical brain state enhancing the probability of gaining insight into covert task regularities. Both non-rapid eye movement (NREM) and rapid eye movement (REM) sleep have been implicated with offline re-activation and reorganization of memories supporting explicit knowledge generation. According to two-stage models of sleep function, offline processing of information during sleep is sequential requiring multiple cycles of NREM and REM sleep stages. However, the role of overnight dynamic sleep macrostructure for insightfulness has not been studied so far. In the present study, we test the hypothesis that the frequency of interactions between NREM and REM sleep stages might be critical for awareness after sleep. For that aim, the rate of sleep stage transitions was evaluated in 53 participants who learned implicitly a serial reaction time task (SRTT) in which a determined sequence was inserted. The amount of explicit knowledge about the sequence was established by verbal recall after a night of sleep following SRTT learning. Polysomnography was recorded in this night and in a control night before and was analyzed to compare the rate of sleep-stage transitions between participants who did or did not gain awareness of task regularity after sleep. Indeed, individual ability of explicit knowledge generation was strongly associated with increased rate of transitions between NREM and REM sleep stages and between light sleep stages and slow wave sleep. However, the rate of NREM–REM transitions specifically predicted the amount of explicit knowledge after sleep in a trait-dependent way. These results demonstrate that enhanced lability of sleep goes along with individual ability of knowledge awareness. Observations suggest that facilitated dynamic interactions between sleep stages, particularly between NREM and REM sleep stages play a role for offline processing which promotes rule extraction and awareness. PMID:26441730

  18. An Evaluation of Functional Variables Affecting Severe Problem Behaviors in Adults with Mental Retardation by Using the Questions about Behavioral Function Scale (QABF).

    ERIC Educational Resources Information Center

    Applegate, Heather; Matson, Johnny L.; Cherry, Katie E.

    1999-01-01

    A study used the Questions about Behavior Function Scale to examine the functions of five severe problem behaviors (self-injurious behavior, aggression, stereotypies, pica, and rumination) in 417 institutionalized persons with mental retardation. The most common function for all behaviors except aggression was nonsocial. Aggression was maintained…

  19. Mitochondrial superoxide mediates labile iron level: evidence from Mn-SOD-transgenic mice and heterozygous knockout mice and isolated rat liver mitochondria.

    PubMed

    Ibrahim, Wissam H; Habib, Hosam M; Kamal, Hina; St Clair, Daret K; Chow, Ching K

    2013-12-01

    Superoxide is the main reactive oxygen species (ROS) generated by aerobic cells primarily in mitochondria. It is also capable of producing other ROS and reactive nitrogen species (RNS). Moreover, superoxide has the potential to release iron from its protein complexes. Unbound or loosely bound cellular iron, known as labile iron, can catalyze the formation of the highly reactive hydroxyl radical. ROS/RNS can cause mitochondrial dysfunction and damage. Manganese superoxide dismutase (Mn-SOD) is the chief ROS-scavenging enzyme and thereby the primary antioxidant involved in protecting mitochondria from oxidative damage. To investigate whether mitochondrial superoxide mediates labile iron in vivo, the levels of labile iron were determined in the tissues of mice overexpressing Mn-SOD and heterozygous Mn-SOD-knockout mice. Furthermore, the effect of increased mitochondrial superoxide generation on labile iron levels was determined in isolated rat liver mitochondria exposed to various electron transport inhibitors. The results clearly showed that increased expression of Mn-SOD significantly lowered the levels of labile iron in heart, liver, kidney, and skeletal muscle, whereas decreased expression of Mn-SOD significantly increased the levels of labile iron in the same organs. In addition, the data showed that peroxidative damage to membrane lipids closely correlated with the levels of labile iron in various tissues and that altering the status of Mn-SOD did not alter the status of other antioxidant systems. Results also showed that increased ROS production in isolated liver mitochondria significantly increased the levels of mitochondrial labile iron. These findings constitute the first evidence suggesting that mitochondrial superoxide is capable of releasing iron from its protein complexes in vivo and that it could also release iron from protein complexes contained within the organelle.

  20. A Novel Method for Efficient Preparation of Mucosal Adjuvant Escherichia coli Heat-Labile Enterotoxin Mutant (LTm) by Artificially Assisted Self-Assembly In Vitro.

    PubMed

    Liu, Di; Zhang, Na; Zheng, Wenyun; Guo, Hua; Wang, Xiaoli; Wang, Tianwen; Wang, Ping; Ma, Xingyuan

    2016-04-01

    As well-known powerful mucosal adjuvant proteins, Escherichia coli heat-labile enterotoxin (LT) and its non-toxic or low-toxic mutants (LTm) are capable of promoting strong mucosal immune responses to co-administered antigens in various types of vaccines. However, due to the complex composition and special structure, the yield of LTm directly from the recombinant genetic engineering strains is quite low. Here, we put forward a novel method to prepare LTm protein which designed, expressed, and purified three kinds of component subunits respectively and assembled them into a hexamer structure in vitro by two combination modes. In addition, by simulated in vivo environment of polymer protein assembly, the factors of the protein solution system which include environment temperature, pH, ionic strength of the solution, and ratio between each subunit were taken into consideration. Finally, we confirmed the optimal conditions of two assembly strategies and prepared the hexamer holotoxin in vitro. These results are not only an important significance in promoting large-scale preparation of the mucosal adjuvant LTm but also an enlightening to produce other multi-subunit proteins.

  1. Dissolved and labile concentrations of Cd, Cu, Pb, and Zn in the South Fork Coeur d'Alene River, Idaho: Comparisons among chemical equilibrium models and implications for biotic ligand models

    USGS Publications Warehouse

    Balistrieri, L.S.; Blank, R.G.

    2008-01-01

    In order to evaluate thermodynamic speciation calculations inherent in biotic ligand models, the speciation of dissolved Cd, Cu, Pb, and Zn in aquatic systems influenced by historical mining activities is examined using equilibrium computer models and the diffusive gradients in thin films (DGT) technique. Several metal/organic-matter complexation models, including WHAM VI, NICA-Donnan, and Stockholm Humic model (SHM), are used in combination with inorganic speciation models to calculate the thermodynamic speciation of dissolved metals and concentrations of metal associated with biotic ligands (e.g., fish gills). Maximum dynamic metal concentrations, determined from total dissolved metal concentrations and thermodynamic speciation calculations, are compared with labile metal concentrations measured by DGT to assess which metal/organic-matter complexation model best describes metal speciation and, thereby, biotic ligand speciation, in the studied systems. Results indicate that the choice of model that defines metal/organic-matter interactions does not affect calculated concentrations of Cd and Zn associated with biotic ligands for geochemical conditions in the study area, whereas concentrations of Cu and Pb associated with biotic ligands depend on whether the speciation calculations use WHAM VI, NICA-Donnan, or SHM. Agreement between labile metal concentrations and dynamic metal concentrations occurs when WHAM VI is used to calculate Cu speciation and SHM is used to calculate Pb speciation. Additional work in systems that contain wide ranges in concentrations of multiple metals should incorporate analytical speciation methods, such as DGT, to constrain the speciation component of biotic ligand models. ?? 2008 Elsevier Ltd.

  2. [Impact of Land Utilization Pattern on Distributing Characters of Labile Organic Carbon in Soil Aggregates in Jinyun Mountain].

    PubMed

    Li, Rui; Jiang, Chang-sheng; Hao, Qing-ju

    2015-09-01

    Four land utilization patterns were selected for this study in Jinyun mountain, including subtropical evergreen broad-leaved forest (abbreviation: forest), sloping farmland, orchard and abandoned land. Soil samples were taken every 10 cm in the depth of 60 cm soil and proportions of large macroaggregates (> 2 mm), small macroaggregates (0. 25-2 mm), microaggregates (0. 053 - 0. 25 mm) and silt + clay (<0. 053 mm) were obtained by wet sieving method to measure the content of organic carbon and labile organic carbon in each aggregate fraction and analyze impacts of land uses on organic carbon and labile organic carbon of soil aggregates. LOC content of four soil aggregates were significantly reduced with the increase of soil depth; in layers of 0-60 cm soil depth, our results showed that LOC contents of forest and abandoned land were higher than orchard and sloping farmland. Reserves of labile organic carbon were estimated by the same soil quality, it revealed that forest (3. 68 Mg.hm-2) > abandoned land (1. 73 Mg.hm-2) > orchard (1. 43 Mg.hm-2) >sloping farmland (0.54 Mg.hm-2) in large macroaggregates, abandoned land (7.77, 5. 01 Mg.hm-2) > forest (4. 96, 2.71 Mg.hm-2) > orchard (3. 33, 21. 10 Mg.hm-2) > sloping farmland (1. 68, 1. 35 Mg.hm-2) in small macroaggregates and microaggregates, and abandoned land(4. 32 Mg.hm-2) > orchard(4. 00 Mg.hm-2) > forest(3. 22 Mg.hm-2) > sloping farmland (2.37 Mg.hm-2) in silt + clay, forest and abandoned land were higher than orchard and sloping farmland in other three soil aggregates except silt + clay. It was observed that the level of organic carbon and labile organic carbon were decreased when bringing forest under cultivation to orchard or farmland, and augments on organic carbon and labile organic carbon were found after exchanging farmland to abandoned land. The most reverses of forest and abandoned land emerged in small macroaggregates, orchard and sloping farmland were in microaggregates. That was, during the

  3. Bipolar Mass Spectrometry of Labile Coordination Complexes, Redox Active Inorganic Compounds, and Proteins Using a Glass Nebulizer for Sonic-Spray Ionization

    NASA Astrophysics Data System (ADS)

    Antonakis, Manolis M.; Tsirigotaki, Alexandra; Kanaki, Katerina; Milios, Constantinos J.; Pergantis, Spiros A.

    2013-08-01

    In this study, we report on the development of a novel nebulizer configuration for sonic-spray ionization (SSI) mass spectrometry (MS), more specifically for a version of SSI that is referred to as Venturi easy ambient sonic-spray ionization (V-EASI) MS. The developed nebulizer configuration is based on a commercially available pneumatic glass nebulizer that has been used extensively for aerosol formation in atomic spectrometry. In the present study, the nebulizer was modified in order to achieve efficient V-EASI-MS operation. Upon evaluating this system, it has been demonstrated that V-EASI-MS offers some distinct advantages for the analysis of coordination compounds and redox active inorganic compounds over the predominantly used electrospray ionization (ESI) technique. Such advantages, for this type of compounds, are demonstrated here for the first time. More specifically, a series of labile heptanuclear heterometallic [CuII 6LnIII] clusters held together with artificial amino acid ligands, in addition to easily oxidized inorganic oxyanions of selenium and arsenic, were analyzed. The observed advantages pertain to V-EASI appearing to be a "milder" ionization source than ESI, not requiring electrical potentials for gas phase ion formation, thus eliminating the possibility of unwanted redox transformations, allowing for the "simultaneous" detection of negative and positive ions (bipolar analysis) without the need to change source ionization conditions, and also not requiring the use of syringes and delivery pumps. Because of such features, especially because of the absence of ionization potentials, EASI can be operated with minimal requirements for source parameter optimization. We observed that source temperature and accelerating voltage do not seem to affect labile compounds to the extent they do in ESI-MS. In addition, bipolar analysis of proteins was demonstrated here by acquiring both positive and negative ion mass spectra from the same protein solutions

  4. Evaluation of free/labile concentrations of trace metals in Athabasca oil sands region streams (Alberta, Canada) using diffusive gradient in thin films and a thermodynamic equilibrium model.

    PubMed

    Zhu, Y; Guéguen, C

    2016-12-01

    The Athabasca's oil sands exploitation is controversial due to its potential risks to water quality but little is known about the temporal changes in the most bioavailable fraction of metal, the free/labile species. In this study, diffusive gradient in thin films (DGT) and the Windermere Humic Aqueous Model (WHAM VII) equilibrium model were used to examine the temporal changes in free/labile metal (Cu, Ni, Zn, Pb) species in three tributaries of the north-flowing Athabasca River in the Athabasca oil sands region (AOSR). The influence of dissolved organic matter (DOM) composition (i.e. fulvic: humic ratio) on modeled Cu and Ni speciation showed a negligible effect on the labile concentration. The best agreements (92 ± 8%) between DGT-labile and WHAM calculated labile concentrations were found assuming the formation of iron oxyhydroxides (FeO(OH)). The agreement was only 70 ± 7% in the presence of inorganic colloidal aluminum oxyhydroxides (AlO(OH)) and in the absence of any inorganic colloids. Together these results suggest that a change in DOM composition had limited impacts on modeled free metal ion concentrations. Although the concentration of the main metal ligand (i.e. DOM), varied from 9 to 40 ppm, no significant temporal differences in the abundance of WHAM-modeled labile species were found, suggesting mobility and bioavailability of Cu, Ni, Pb and Zn were comparable over the 2003-2012 period.

  5. Long term assessment of factors affecting nitrifying bacteria communities and N-removal in a full-scale biological process treating high strength hazardous wastewater.

    PubMed

    Kim, Young Mo; Park, Hongkeun; Cho, Kyung Hwa; Park, Jong Moon

    2013-04-01

    Over a 3 year period, interactions between nitrifying bacterial communities and the operational parameters of a full-scale wastewater treatment plant were analyzed to assess their impact on nitrification performance. Throughout the study period, nitrification fluctuated while Nitrosomonas europaea and Nitrosomonas nitrosa, the two major ammonia oxidizing bacteria (AOB) communities, showed resistance to changes in operational and environmental conditions. Nitrobacter populations mostly exceeded those of Nitrospira within nitrite oxidizing bacteria (NOB). Meanwhile, principal component analysis (PCA) results revealed that a close association between Nitrobacter and nitrite concentration as well as a direct correlation between the quantity of AOB and influent SCN- concentration. The serial shifts of data points over time showed that the nitrification of a full-scale treatment plant has been gradually suppressed by the influence of influent COD and phenol concentrations.

  6. Affective processing requires awareness.

    PubMed

    Lähteenmäki, Mikko; Hyönä, Jukka; Koivisto, Mika; Nummenmaa, Lauri

    2015-04-01

    Studies using backward masked emotional stimuli suggest that affective processing may occur outside visual awareness and imply primacy of affective over semantic processing, yet these experiments have not strictly controlled for the participants' awareness of the stimuli. Here we directly compared the primacy of affective versus semantic categorization of biologically relevant stimuli in 5 experiments (n = 178) using explicit (semantic and affective discrimination; Experiments 1-3) and implicit (semantic and affective priming; Experiments 4-5) measures. The same stimuli were used in semantic and affective tasks. Visual awareness was manipulated by varying exposure duration of the masked stimuli, and subjective level of stimulus awareness was measured after each trial using a 4-point perceptual awareness scale. When participants reported no awareness of the stimuli, semantic and affective categorization were at chance level and priming scores did not differ from zero. When participants were even partially aware of the stimuli, (a) both semantic and affective categorization could be performed above chance level with equal accuracy, (b) semantic categorization was faster than affective categorization, and (c) both semantic and affective priming were observed. Affective categorization speed was linearly dependent on semantic categorization speed, suggesting dependence of affective processing on semantic recognition. Manipulations of affective and semantic categorization tasks revealed a hierarchy of categorization operations beginning with basic-level semantic categorization and ending with superordinate level affective categorization. We conclude that both implicit and explicit affective and semantic categorization is dependent on visual awareness, and that affective recognition follows semantic categorization.

  7. Visibility conditions and diel period affect small-scale spatio-temporal behaviour of pike Esox lucius in the absence of prey and conspecifics.

    PubMed

    Nilsson, P A; Baktoft, H; Boel, M; Meier, K; Jacobsen, L; Rokkjaer, E M; Clausen, T; Skov, C

    2012-05-01

    Pike Esox lucius in the absence of prey and conspecifics were shown to have the highest habitat-change activity during dusk and to decrease preference for complex habitats in turbid water. As the behaviours indicate routine responses in the absence of behavioural interactions, E. lucius spatio-temporal distributions should be directly affected and thereby more easily assessed and avoided by prey, with potential consequences for encounter rates.

  8. Mineralogy and trace element relative solubility patterns of shallow marine sediments affected by submarine tailings disposal and artisanal gold mining, Buyat-Ratototok district, North Sulawesi, Indonesia

    NASA Astrophysics Data System (ADS)

    Blackwood, George M.; Edinger, Evan N.

    2007-04-01

    Shallow marine sediments of the Buyat-Ratototok district of North Sulawesi, Indonesia, are affected by submarine disposal of industrial gold mine tailings and small-scale gold mining using mercury amalgamation. Industrial mine tailings contained 590 660 ppm arsenic, 490 580 ppm antimony, and 0.8 5.8 ppm mercury. Electron microprobe survey found both colloidal iron arsenic-phases without sulphur and arsenian pyrite in tailings and sites to which tailings had dispersed, but only arsenopyrite in sediments affected by artisanal mining. Antimony in tailings was present as antimony oxides, colloidal iron antimony phases, colloidal iron antimony phases, and stibnite in sediments affected by both types of mining. A sequential extraction found that 2% of arsenic held in tailings and tailings-contaminated sediments was exchangeable, 20 30% was labile, including weakly adsorbed, carbonate- and arsenate bound, 20 30% was metastable, probably incorporated into iron or manganese oxyhydroxides, or strongly adsorbed to silicate minerals, and 40 48% was relatively insoluble, probably incorporated into sulphides or silicates. Arsenic in sediments affected by artisanal gold mining was 75 95% relatively insoluble. Antimony in all sediments was >90% relatively insoluble. Relative solubility patterns of most other metals did not differ between industrial tailings-affected, artisanal-mining affected areas, and fluvial sediments. Results suggest that submarine tailings disposal is not suitable for refractory Carlin-like gold deposits because ore processing converts arsenic to forms unstable in anoxic marine sediments.

  9. Molybdenum(VI) speciation in sulfidic waters: Stability and lability of thiomolybdates

    SciTech Connect

    Erickson, B.E.; Helz, G.R.

    2000-04-01

    of fixed, but acid-labile sulfide in oxic waters.

  10. The surprising lability of bis(2,2':6',2''-terpyridine)chromium(III) complexes.

    PubMed

    Constable, Edwin C; Housecroft, Catherine E; Neuburger, Markus; Schönle, Jonas; Zampese, Jennifer A

    2014-05-21

    The complex [Cr(tpy)(O3SCF3)3] (tpy = 2,2':6',2''-terpyridine) is readily made from [Cr(tpy)Cl3] and is a convenient precursor to [Cr(tpy)2][PF6]3 and to [Cr(tpy)(4'-(4-tolyl)tpy)][PF6]3 and [Cr(tpy)(5,5''-Me2tpy)][PF6]3 (4'-(4-tolyl)tpy = 4'-(4-tolyl)-2,2':6',2''-terpyridine; 5,5''-Me2tpy = 5,5''-dimethyl-2,2':6',2''-terpyridine); these are the first examples of heteroleptic bis(tpy) chromium(III) complexes. The single crystal structures of 2{[Cr(tpy)2][PF6]3}·5MeCN, [Cr(tpy)(4'-(4-tolyl)tpy)][PF6]3·3MeCN and [Cr(tpy)(5,5''-Me2tpy)][PF6]3·3MeCN have been determined. Each cation contains the expected octahedral {Cr(tpy)2}(3+) unit; in all three structures, the need to accommodate three anions per cation and the solvent molecules prevents the formation of a grid-like array of cations that is typical of many lattices containing {M(tpy)2}(2+) motifs. Three reversible electrochemical processes are observed for [Cr(tpy)(4'-(4-tolyl)tpy)][PF6]3 and [Cr(tpy)(5,5''-Me2tpy)][PF6]3, consistent with those documented for [Cr(tpy)2](3+). At pH 6.36, aqueous solutions of [Cr(tpy)2][PF6]3 are stable for at least two months. However, contrary to the expectations of the d(3) Cr(3+) ion being a kinetically inert metal centre, the tpy ligands in [Cr(tpy)2](3+) are labile in the presence of base; absorption and (1)H NMR spectroscopies have been used to monitor the effects of adding NaOH to aqueous and CD3OD solutions, respectively, of the homo- and heteroleptic complexes. Ligand dissociation is also observed when [Bu4N]F is added to CD3OD solutions of the complexes, but in aqueous solution, [Cr(tpy)2][PF6]3 is stable in the presence of fluoride ion.

  11. Labile carbon regulates protease activity and nitrogen acquisition in boreal forest topsoil.

    NASA Astrophysics Data System (ADS)

    Lindén, A.; Heinonsalo, J.; Oinonen, M.; Sonninen, E.; Hilasvuori, E.; Pumpanen, J.

    2012-04-01

    In boreal zone, soil organic matter (SOM) contains a substantial amount of recalcitrant material and forms a large nitrogen pool. However, this pool is to a great extent inaccessible to plants, due to its low decomposability. Although, the nitrogen supply is the most limiting factor of net ecosystem production (NEP) in boreal forests, it has been speculated that as a result of the accelerated decomposition of SOM induced by climate warming, part of this nitrogen pool could be released. It has also been shown that a substantial proportion of gross primary production (GPP) is allocated below ground and acts as an energy source for decomposing rhizomicrobial organisms, and that changes in the GPP rate could therefore increase the belowground turn over rate of otherwise recalcitrant nitrogen-rich SOM. We were studying the effects of increasing labile carbon input on the symbiotic microbial N acquisition and protease activities in a controlled microcosm experiment. We compared the natural abundance of isotope ratios of 13C and 14C in soil CO2efflux, protease enzyme activity, natural abundance of 15N in the needles, and microbial biomass in microcosms containing bare soil and tree seedlings. In addition, we had treatments were additional energy was given to the bare soil and seedling microcosms in the form of glucose. The age of the CO2 originating from the decomposition process of SOM was older in all treatments where easily decomposable carbon (energy) was available for soil microorganisms. The increased natural abundance of 15N in the needles of the seedlings treated with glucose, suggests a shift in nitrogen acquisition to different SOM pool, which was reflected strongly to the total N content of the SOM and evolving 13C signature in soil CO2 efflux. The protease activity was highest in treatments with artificial glucose addition. Our results suggest that the increased input of easily available carbon from aboveground enables the decomposition of recalcitrant

  12. Detection of Labile Low-Molecular-Mass Transition Metal Complexes in Mitochondria

    PubMed Central

    McCormick, Sean P.; Moore, Michael J.; Lindahl, Paul A.

    2015-01-01

    Liquid chromatography was used with an on-line inductively coupled plasma mass spectrometer to detect low-molecular-mass (LMM) transition metal complexes in mitochondria isolated from fermenting yeast cells, human Jurkat cells, and mouse brain and liver. These complexes constituted 20 – 40% of total mitochondrial Mn, Fe, Zn, and Cu ions. The major LMM Mn complex in yeast mitochondria had a mass of ca. 1100 Da and a concentration of ~ 2 μM. Mammalian mitochondria contained a second Mn species with a mass of ca. 2000 Da at a comparable concentration. The major Fe complex in mitochondria isolated from exponentially growing yeast cells had a mass of ca. 580 Da; the concentration of Fe580 in mitochondria was ca. 100 μM. When mitochondria were isolated from fermenting cells in post-exponential phase, the mass of the dominant LMM Fe complex was ca. 1100 Da. Upon incubation, the intensity of Fe1100 declined and Fe580 increased, suggesting that the two are interrelated. Mammalian mitochondria contained Fe580 and 2 other Fe species (Fe2000 and Fe1100) at concentrations of ca. 50 μM each. The dominant LMM Zn species in mitochondria had a mass of ca. 1200 Da and a concentration of ca. 110 μM. Mammalian mitochondria contained a second major LMM Zn species at 1500 Da. The dominant LMM Cu species in yeast mitochondria had a mass of ca. 5000 Da and a concentration in yeast mitochondria of ca. 16 μM; Cu5000 was not observed in mammalian mitochondria. The dominant Co species in mitochondria, Co1200, had a concentration of 20 nM and was probably a cobalamin. Mammalian but not yeast mitochondria contained a LMM Mo species, Mo730, at ca. 1 μM concentration. Increasing Mn, Fe, Cu, and Zn concentrations 10 fold in the medium increased the concentration of the same element in the corresponding isolated mitochondria. Treatment with metal chelators confirmed that these LMM species were labile. The dominant S species at 1100 Da was not free GSH or GSSG. PMID:26018429

  13. Refined structure of Escherichia coli heat-labile enterotoxin, a close relative of cholera toxin.

    PubMed

    Sixma, T K; Kalk, K H; van Zanten, B A; Dauter, Z; Kingma, J; Witholt, B; Hol, W G

    1993-04-05

    Heat-labile enterotoxin (LT) from Escherichia coli is a bacterial protein toxin with an AB5 multimer structure, in which the B pentamer has a membrane binding function and the A subunit is needed for enzymatic activity. The LT crystal structure has been solved using a combination of multiple isomorphous replacement, fivefold averaging and molecular dynamics refinement. Phase combination using all these sources of phase information was of crucial importance for the chain tracing. The structure has now been refined to 1.95 A resolution, resulting in a model containing 6035 protein atoms and 293 solvent molecules with a crystallographic R-factor of 18.2% and good stereochemistry. The B subunits are arranged as a highly stable pentamer with a donut shape. Each subunit takes part in approximately 30 inter-subunit hydrogen bonds and six salt bridges with its two neighbors, whilst burying a large surface area. The A subunit has higher temperature factors and less well-defined secondary structure than the B subunits. It interacts with the B pentamer mainly via the C-terminal A2 fragment, which runs through the highly charged central pore of the B subunits. The pore contains at least 66 water molecules, which fill the space left by the A2 fragment. A detailed analysis of the contacts between A and B subunits showed that most specific contacts occur at the entrance of the central pore of the B pentamer, while the contacts within the pore are mainly hydrophobic and water mediated, with the exception of two salt bridges. Only a few contacts exist between the A1 fragment and the B pentamer, showing that the A2 fragment functions as a "linker" of the A and B parts of the protein. Interacting with the A subunit by the B subunits does not cause large deviations from a common B subunit structure, and the 5-fold symmetry is well maintained. A potential NAD(+)-binding site is located in an elongated crevice at the interface of two small sheets in the A1 fragment. At the back of this

  14. Modeling watershed-scale (137)Cs transport in a forested catchment affected by the Fukushima Dai-ichi Nuclear Power Plant accident.

    PubMed

    Wei, Lezhang; Kinouchi, Tsuyoshi; Yoshimura, Kazuya; Velleux, Mark L

    2017-02-02

    The Fukushima nuclear accident in 2011 resulted in (137)Cs contamination of large areas in northeast Japan. A watershed-scale (137)Cs transport model was developed and applied to a forested catchment in Fukushima area. This model considers (137)Cs wash-off from vegetation, movement through soils, and transport of dissolved and particulate (137)Cs adsorbed to clay, silt and sand. Comparisons between measurements and simulations demonstrated that the model well reproduced (137)Cs concentrations in the stream fed from the catchment. Simulations estimated that 0.57 TBq of (137)Cs was exported from the catchment between June, 2011 and December, 2014. Transport largely occurred with eroded sediment particles at a ratio of 17:70:13 of clay, silt, and sand. The overall (137)Cs reduction ratio by rainfall-runoff wash-off was about 1.6%. Appreciable (137)Cs remained in the catchment at the end of 2014. The largest rate of (137)Cs reduction by wash-off was simulated to occur in subwatersheds of the upper catchment. However, despite relatively low initial deposition, middle portions of the watershed exported proportionately more (137)Cs by rainfall-runoff processes. Simulations indicated that much of the transported (137)Cs originates from erosion over hillsides and river banks. These results suggested that areas where (137)Cs accumulates with redeposited sediments can be targeted for decontamination and also provided insight into (137)Cs transport at the watershed scale to assess risk management and decontamination planning efforts.

  15. Physiologic variability at the verge of systemic inflammation: multi-scale entropy of heart rate variability is affected by very low doses of endotoxin

    PubMed Central

    Herlitz, Georg N.; Sanders, Renee L.; Cheung, Nora H.; Coyle, Susette M.; Griffel, Benjamin; Macor, Marie A.; Lowry, Stephen F.; Calvano, Steve E.; Gale, Stephen C.

    2014-01-01

    Introduction Human injury or infection induces systemic inflammation with characteristic neuro-endocrine responses. Fluctuations in autonomic function during inflammation are reflected by beat-to-beat variation in heart rate, termed heart rate variability (HRV). In the present study, we determine threshold doses of endotoxin needed to induce observable changes in markers of systemic inflammation, we investigate whether metrics of HRV exhibit a differing threshold dose from other inflammatory markers, and we investigate the size of data sets required for meaningful use of multi-scale entropy (MSE) analysis of HRV. Methods Healthy human volunteers (n=25) were randomized to receive placebo (normal saline) or endotoxin/lipopolysaccharide (LPS): 0.1, 0.25, 0.5, 1.0, or 2.0 ng/kg administered intravenously. Vital signs were recorded every 30 minutes for 6 hours and then at 9, 12, and 24 hours after LPS. Blood samples were drawn at specific time points for cytokine measurements. HRV analysis was performed using EKG epochs of 5 minutes. MSE for HRV was calculated for all dose groups to scale factor 40. Results The lowest significant threshold dose was noted in core temperature at 0.25ng/kg. Endogenous TNF-α and IL-6 were significantly responsive at the next dosage level (0.5ng/kg) along with elevations in circulating leukocytes and heart rate. Responses were exaggerated at higher doses (1 and 2 ng/kg). Time domain and frequency domain HRV metrics similarly suggested a threshold dose, differing from placebo at 1.0 and 2.0 ng/kg, below which no clear pattern in response was evident. By applying repeated-measures ANOVA across scale factors, a significant decrease in MSE was seen at 1.0 and 2.0 ng/kg by 2 hours post exposure to LPS. While not statistically significant below 1.0 ng/kg, MSE unexpectedly decreased across all groups in an orderly dose-response pattern not seen in the other outcomes. Conclusions By usingrANOVA across scale factors, MSE can detect autonomic change

  16. Development and validation of the positive affect and well-being scale for the neurology quality of life (Neuro-QOL) measurement system

    PubMed Central

    Salsman, John M.; Victorson, David; Choi, Seung W.; Peterman, Amy H.; Heinemann, Allen W.; Nowinski, Cindy; Cella, David

    2013-01-01

    Purpose To develop and validate an item-response theory-based patient-reported outcomes assessment tool of positive affect and well-being (PAW). This is part of a larger NINDS-funded study to develop a health-related quality of life measurement system across major neurological disorders, called Neuro-QOL. Methods Informed by a literature review and qualitative input from clinicians and patients, item pools were created to assess PAW concepts. Items were administered to a general population sample (N = 513) and a group of individuals with a variety of neurologic conditions (N = 581) for calibration and validation purposes, respectively. Results A 23-item calibrated bank and a 9-item short form of PAW was developed, reflecting components of positive affect, life satisfaction, or an overall sense of purpose and meaning. The Neuro-QOL PAW measure demonstrated sufficient unidimensionality and displayed good internal consistency, test–retest reliability, model fit, convergent and discriminant validity, and responsiveness. Conclusion The Neuro-QOL PAW measure was designed to aid clinicians and researchers to better evaluate and understand the potential role of positive health processes for individuals with chronic neurological conditions. Further psychometric testing within and between neurological conditions, as well as testing in non-neurologic chronic diseases, will help evaluate the generalizability of this new tool. PMID:23526093

  17. Effects of composition of labile organic matter on biogenic production of methane in the coastal sediments of the Arabian Sea.

    PubMed

    Gonsalves, Maria-Judith; Fernandes, Christabelle E G; Fernandes, Sheryl Oliveira; Kirchman, David L; Bharathi, P A Loka

    2011-11-01

    Coastal regions are potential zones for production of methane which could be governed by ecological/environmental differences or even sediment properties of a niche. In order to test the hypothesis that methanogenesis in most marine sediments could be driven more by proteins than by carbohydrates and lipid content of labile organic matter (LOM), incubation experiments were carried out with sediments from different environmental niches to measure methane production. The methane production rates were examined in relationship to the sediment biochemistry, i.e., carbohydrates, proteins, and lipids. The gas production measured by head space method ranged from 216 ng g( -1) day( -1) in the mangrove sediments to 3.1 μg g( -1) day( -1) in the shallow Arabian Sea. LOM ranged from 1.56 to 2.85 mg g( -1) in the shallow Arabian Sea, from 3.35 to 5.43 mg g( -1) in the mangrove estuary, and from 0.66 to 0.70 mg g( -1) in the sandy sediments with proteins contributing maximum to the LOM pool. Proteins influenced methane production in the clayey sediments of shallow depths of the Arabian Sea (r = 0.933, p < 0.001) and mangrove estuary (r = 0.981, p < 0.001) but in the sandy beach sediments, carbohydrates (r = 0.924, p < 0.001) governed the net methane production. The gas production was more pronounced in shallow and surface sediments and it decreased with depth apparently governed by the decrease in lability index. Thus, the lability index and protein content are important factors that determine methane production rates in these coastal ecosystems.

  18. Induction of heat-labile sites in DNA of mammalian cells by the antitumor alkylating drug CC-1065

    SciTech Connect

    Zsido, T.J.; Woynarowski, J.M.; Baker, R.M.; Gawron, L.S.; Beerman, T.A. )

    1991-04-16

    CC-1065 is a very potent antitumor antibiotic capable of covalent and noncovalent binding to the minor groove of naked DNA. Upon thermal treatment, covalent adducts formed between CC-1065 and DNA generate strand break. The authors have shown that this molecular damage can be detected following CC-1065 treatment of mammalian whole cells. Using alkaline sucrose gradient analysis, They observe thermally induced breakage of ({sup 14}C)thymidine-prelabeled DNA from drug-treated African green monkey kidney BSC-1 cells. Very little damage to cellular DNA by CC-1065 can be detected without first heating the drug-treated samples. CC-1065 can also generate heat-labile sites within DNA during cell lysis and heating, subsequent to the exposure of cells to drug, suggesting that a pool of free and noncovalently bound drug is available for posttreatment adduct formation. This effect was controlled for by mixing ({sup 3}H)thymidine-labeled untreated cells with the ({sup 14}C)thymidine-labeled drug-treated samples. The lowest drug dose at which heat-labile sites were detected was 3 nM CC-1065 (3 single-stranded breaks/10{sup 6} base pairs). This concentration reduced survival of BSC-1 cells to 0.1% in cytotoxicity assays. The generation of CC-1065-induced lesions in cellular DNA is time dependent (the frequency of lesions caused by a 60 nM treatment reaching a plateau at 2 h) and is not readily reversible. The results of this study demonstrate that CC-1065 does generate heat-labile sites with the cellular DNA of intact cells and suggest that a mechanism of cytotoxic action of CC-1065 involves formation of covalent adducts to DNA.

  19. Differences in dissolved organic matter lability between alpine glaciers and alpine rock glaciers of the American West

    NASA Astrophysics Data System (ADS)

    Hall, E.; Fegel, T. S., II; Baron, J.; Boot, C. M.

    2015-12-01

    While alpine glaciers in montane regions represent the largest flux of dissolved organic matter (DOM) from global ice melt no research has examined the bioavailability of DOM melted out of glacial ice in the western continental United States. Furthermore, rock glaciers are an order of magnitude more abundant than ice glaciers in U.S., yet are not included in budgets for perennial ice carbon stores. Our research aims to understand differences in the bioavailability of carbon from ice glaciers and rock glaciers along the Central Rocky Mountains of Colorado. Identical microbial communities were fed standardized amounts of DOM from four different ice glacier-rock glaciers pairs. Using laboratory incubations, paired with mass spectrometry based metabolomics and 16S gene sequencing; we were able to examine functional definitions of DOM lability in glacial ice. We hypothesized that even though DOM quantities are similar in the outputs of both glacial types in our study area, ice glacial DOM would be more bioavailable than DOM from rock glaciers due to higher proportions of byproducts from microbial metabolism than rock glacier DOM, which has higher amounts of "recalcitrant" plant material. Our results show that DOM from ice glaciers is more labile than DOM from geologically and geographically similar paired rock glaciers. Ice glacier DOM represents an important pool of labile carbon to headwater ecosystems of the Rocky Mountains. Metabolomic analysis shows numerous compounds from varying metabolite pathways, including byproducts of nitrification before and after incubation, meaning that, similar to large maritime glaciers in Alaska and Europe, subglacial environments in the mountain ranges of the United States are hotspots for biological activity and processing of organic carbon.

  20. Land-use impacts on profile distribution of labile and recalcitrant carbon in the Ili River Valley, northwest China.

    PubMed

    Liu, Xiang; Li, Lanhai; Qi, Zhiming; Han, Jiangang; Zhu, Yongli

    2017-05-15

    There is a growing evidence that the decomposition of recalcitrant carbon (C) can be stimulated by environmental changes, such as fresh C supply and increased temperature. However, the effect of land-use on profile distribution of recalcitrant C content is still poorly understood. In this study, soil samples were collected to a depth of 100cm from pastures and four major croplands including maize field, wheat field, paddy and apple orchard in the Ili River Valley, northwest China, to investigate the effects of land-use on profile distribution of labile organic C (LOC), semi-labile organic C (SLOC), recalcitrant organic C (ROC) and their relative proportions in total organic C (TOC), and evaluate whether such effects can be different between topsoil (0-20cm) and subsoil (20-100cm). The results showed that soil ROC accounting for 49.4-66.3% of TOC for different land-uses, implying that ROC is the major form of soil organic C (SOC). Soil TOC contents of croplands were 20.4-85.2% lower than those of pastures along the soil profile, indicating that SOC pool may be decreased by agricultural land-uses. The lower contents of LOC, SLOC and ROC in croplands than in pastures suggested that the decreases in TOC content in croplands are not only due to the decreases in labile C pool but also the reductions in recalcitrant C pool. The differences in SOC fractions among land-uses were similar in topsoil and subsoil, while the proportions of each SOC fraction in TOC did not differ significantly between the two soil layers in most cases, indicating that each SOC fraction in subsoil can be also influenced by land-use types. Therefore, it is suggested that the ROC in subsoil, which plays a crucial role in C sequestration, should be taken into account when estimating the effect of land-use on SOC kinetic.

  1. Determination of alkali-labile phosphoprotein phosphorus from fish plasma using the Tb(3+)-tiron complex as a fluorescence probe.

    PubMed

    Lv, Xue-Fei; Zhao, Yi-Bing; Zhou, Qun-Fang; Jiang, Gui-Bin; Song, Mao-Yong

    2007-01-01

    A sensitive method based on the fluorescence quenching effect of the Tb(3+)-Tiron complex is proposed for the determination of alkali-labile phosphoprotein phosphorus (ALP) released from fish plasma. The detection limit was 5.4 ng/ml (S/N = 2), and the relative standard deviation of the quenching effect (6 replicates) was 4.6%. The results obtained by the proposed method were in good agreement with those obtained by the colorimetric assay. The advantages of the present method are its relatively simple detection procedure, the lack of toxic organic solvents, and high sensitivity.

  2. How much do tides affect the circulation of the Mediterranean Sea? From local processes in the Strait of Gibraltar to basin-scale effects

    NASA Astrophysics Data System (ADS)

    Naranjo, C.; Garcia-Lafuente, J.; Sannino, G.; Sanchez-Garrido, J. C.

    2014-09-01

    The effects of tidal forcing on the exchange flow through the Strait of Gibraltar and the circulation in the near-field region are revisited with a regional numerical model. Also a basin-scale model run is conducted in a first attempt to assess the impact of these local processes on the Western Mediterranean thermohaline circulation. In the Strait of Gibraltar, tides are found to (1) increase the exchange flow volume transport, (2) modify the hydrological properties of Atlantic inflowing waters through the enhancement of mixing, and (3) facilitate the drainage of Mediterranean deep water. In the far-field, the model reveals that these local processes can favor deep convection in the Gulf of Lion. Some thoughts are provided offering possible explanations.

  3. Small-scale patterns in snowmelt timing affect gene flow and the distribution of genetic diversity in the alpine dwarf shrub Salix herbacea

    PubMed Central

    Cortés, A J; Waeber, S; Lexer, C; Sedlacek, J; Wheeler, J A; van Kleunen, M; Bossdorf, O; Hoch, G; Rixen, C; Wipf, S; Karrenberg, S

    2014-01-01

    Current threats to biodiversity, such as climate change, are thought to alter the within-species genetic diversity among microhabitats in highly heterogeneous alpine environments. Assessing the spatial organization and dynamics of genetic diversity within species can help to predict the responses of organisms to environmental change. In this study, we evaluated whether small-scale heterogeneity in snowmelt timing restricts gene flow between microhabitats in the common long-lived dwarf shrub Salix herbacea L. We surveyed 273 genets across 12 early- and late-snowmelt sites (that is, ridges and snowbeds) in the Swiss Alps for phenological variation over 2 years and for genetic variation using seven SSR markers. Phenological differentiation triggered by differences in snowmelt timing did not correlate with genetic differentiation between microhabitats. On the contrary, extensive gene flow appeared to occur between microhabitats and slightly less extensively among adjacent mountains. However, ridges exhibited significantly lower levels of genetic diversity than snowbeds, and patterns of effective population size (Ne) and migration (Nem) between microhabitats were strongly asymmetric, with ridges acting as sources and snowbeds as sinks. As no recent genetic bottlenecks were detected in the studied sites, this asymmetry is likely to reflect current meta-population dynamics of the species dominated by gene flow via seeds rather than ancient re-colonization after the last glacial period. Overall, our results suggest that seed dispersal prevents snowmelt-driven genetic isolation, and snowbeds act as sinks of genetic diversity. We discuss the consequences of such small-scale variation in gene flow and diversity levels for population responses to climate change. PMID:24619183

  4. Impact assessment and recommendation of alternative conjunctive water use strategies for salt affected agricultural lands through a field scale decision support system - a case study.

    PubMed

    Kaur, Ravinder; Paul, Madhumita; Malik, Rashmi

    2007-06-01

    Conjunctive use of saline/non-saline irrigation waters is generally aimed at minimizing yield losses and enhancing flexibility of cropping, without much alteration in farming operations. Recommendation of location-specific suitable conjunctive water use plans requires assessment of their long-term impacts on soil salinization/sodification and crop yield reductions. This is conventionally achieved through long-term field experiments. However such impact evaluations are site specific, expensive and time consuming. Appropriate decision support systems (DSS) can be time-efficient and cost-effective means for such long-term impact evaluations. This study demonstrates the application of one such (indigenously developed) DSS for recommending best conjunctive water use plans for a, rice-wheat growing, salt affected farmer's field in Gurgaon district of Haryana (India). Before application, the DSS was extensively validated on several farmers and controlled experimental fields in Gurgaon and Karnal districts of Haryana (India). Validation of DSS showed its potential to give realistic estimates of root zone soil salinity (with R = 0.76-0.94; AMRE = 0.03-0.06; RMSPD = 0.51-0.90); sodicity (with R = 0.99; AMRE = 0.02; RMSPD = 0.84) and relative crop yield reductions (AMRE = 0.24), under existing (local) resource management practices. Long term (10 years) root zone salt build ups and associated rice/wheat crop yield reductions, in a salt affected farmer's field, under varied conjunctive water use scenarios were evaluated with the validated DSS. It was observed that long-term applications of canal (CW) and tube well (TW) waters in a cycle and in 1:1 mixed mode, during Kharif season, predicted higher average root zone salt reductions (2-9%) and lower rice crop yield reductions (4-5%) than the existing practice of 3-CW, 3-TW, 3-CW. Besides this, long-term application of 75% CW mixed with 25% TW, during Rabi season, predicted about 17% lower average root-zone salt reductions than

  5. Large-Scale Glycomics of Livestock: Discovery of Highly Sensitive Serum Biomarkers Indicating an Environmental Stress Affecting Immune Responses and Productivity of Holstein Dairy Cows.

    PubMed

    Rehan, Ibrahim F; Ueda, Koichiro; Mitani, Tomohiro; Amano, Maho; Hinou, Hiroshi; Ohashi, Tetsu; Kondo, Seiji; Nishimura, Shin-Ichiro

    2015-12-09

    Because various stresses strongly influence the food productivity of livestock, biomarkers to indicate unmeasurable environmental stress in domestic animals are of increasing importance. Thermal comfort is one of the basic principles of dairy cow welfare that enhances productivity. To discover sensitive biomarkers that monitor such environmental stresses in dairy cows, we herein performed, for the first time, large-scale glycomics on 336 lactating Holstein cow serum samples over 9 months between February and October. Glycoblotting combined with MALDI-TOF/MS and DMB/HPLC allowed for comprehensive glycomics of whole serum glycoproteins. The results obtained revealed seasonal alterations in serum N-glycan levels and their structural characteristics, such as an increase in high-mannose type N-glycans in spring, the occurrence of di/triantennary complex type N-glycans terminating with two or three Neu5Gc residues in summer and autumn, and N-glycans in winter dominantly displaying Neu5Ac. A multivariate analysis revealed a correlation between the serum expression levels of these season-specific glycoforms and productivity.

  6. The Stable and Radio- Carbon Isotopic Content of Labile and Refractory Carbon in Atmospheric Particulate Matter

    NASA Astrophysics Data System (ADS)

    McNichol, A. P.; Rosenheim, B. E.; Gerlach, D. S.; Hayes, J. M.

    2006-12-01

    Studies of the isotopic content of atmospheric particulate matter are hampered by difficulties in chemically defining the pools of carbon and analytically isolating the different pools. We are conducting studies on reference materials and atmospheric aerosol samples to develop a method to measure stable and radio- carbon isotopes on the labile and refractory carbon. We are using a flow-through combustion system that allows us to combust, collect and measure the isotopic content of the gases produced at all stages of heating/oxidizing. We compare our results to those measured using a chemothermal oxidation method (CTO) (Gustafsson et al., 2001). In this method, refractory carbon is defined as the material remaining after pre- combusting a sample at 375°C in the presence of oxygen for 24 hours. The reference materials are diesel soot, apple leaves and a hybrid of the two (DiesApple), all from NIST. These provide carbon with two well-defined fractions -- the soot provides refractory carbon that is radiocarbon dead and the apple leaves provide organic carbon that is radiocarbon modern. Radiocarbon results from DiesApple indicate that the "refractory" carbon defined by the CTO method is actually a mixture of old and modern carbon that contains over 25% modern carbon. This suggests that charred material formed from the apples leaves during the pre-combustion step is contributing to the fraction we identify as refractory carbon. We are studying this by analyzing the individual materials and the mixture using our flow-through system. First results with this system indicate that the refractory fraction trapped from the DiesApple contains much less modern carbon than the CTO method, less than 7%. We will present detailed concentration and isotopic results of the generation of carbon dioxide during programmed combustion of each of the reference materials. We studied the radiocarbon content of both the total carbon (TC) and refractory carbon in the fine particulate matter (PM

  7. Lability of antiretroviral drug resistance mutations--correlates with immunological and virological responses.

    PubMed

    Al Mazari, Ali; Zomaya, Albert Y; Charleston, Michael; Salem, Hanan; Maher, AnnaMarie; Garsia, Roger J

    2007-07-01

    significant increase in mean CD4 cell count occurred thereafter (+242 cells/mm(3), P=0.0077). Similarly, in patients without EoR at the PR site there was no significant change in mean CD4 count during the first 36 months (-19 cells/mm(3), P=0.6647) and there was a significant increase in the last 52 months (+145 cells/mm(3), P=0.0348). The only significant decrease in mean value of VL levels occurred in patients without EoR associated with NRTIs thereafter (-1.33 log(10) copies/ml, P=0.0477), while no significant changes in mean value of VL levels in patients with/without EoR associated with any ARV drugs at any other time points (-0.65 to +0.15 log(10) copies/ml, P=0.1855 to 0.7958). Low CD4 cell counts (<250 cells/mm(3)) and high VL levels (>4.50 log(10) copies/ml) in the early stage of HIV infection, a significant decrease in CD4 cell counts during the first 36 months (-50 or more cells/mm(3)), and high frequencies of mutations during the first 36 months of antiretroviral regimen (>3 mutations) emerged as potential predictive factors of EoR associated with NRTI/PRI agents thereafter. Stable VL in the first 36 months correlated with lack of lability of resistance mutations thereafter.

  8. Size, speciation and lability of NOM-metal complexes in hyperalkaline cave dripwater

    NASA Astrophysics Data System (ADS)

    Hartland, Adam; Fairchild, Ian J.; Lead, Jamie R.; Zhang, Hao; Baalousha, Mohammed

    2011-12-01

    Transport of trace metals by natural organic matter (NOM) is potentially an important vector for trace metal incorporation in secondary cave precipitates [speleothems], yet little is known about the size distribution, speciation and metal binding properties of NOM in cave dripwaters. A hyperalkaline cave environment (ca. pH 11) was selected to provide information on colloid-metal interactions in cave waters, and to address the lack of high-pH data in natural systems in general. Colloidal (1 nm-1 μm) NOM in hyperalkaline cave dripwater from Poole's Cavern, UK, was characterised by flow field-flow fractionation (FlFFF) coupled to UV and fluorescence detectors and transmission electron microscopy (TEM) coupled to X-ray energy-dispersive spectroscopy (X-EDS); trace-metal lability was examined by diffusive gradients in thin films (DGT). Colloidal aggregates and small particulates (>1 μm) imaged by TEM were morphologically heterogeneous with qualitative elemental compositions (X-EDS spectra; n = 41) consistent with NOM aggregates containing aluminosilicates, and iron and titanium oxides. Globular organic colloids, with diameters between ca. 1 and 10 nm were the most numerous colloidal class and exhibited high UV-absorbance (254 nm) and fluorescence intensity (320:400 nm excitation: emission) in optical regions characteristic of humic-like compounds. Metal binding with humic substances was modelled using the WHAM 6.1 (model VI) and visual MINTEQ 3.0 (NICA-Donnan) speciation codes. At pH 11, both models predicted dominant humic binding of Cu (ca. 100%) and minimal binding of Ni and Co (ca. <1-7%). A DGT depletion experiment (7 days duration) with the hyperalkaline dripwater showed that the available proportion of each metal was much lower than its total concentration. Metal availability for DGT in the initial stages (24 h) was consistent with weaker binding of alkaline earth metals by humic substances (Ba > Sr > V > Cu > Ni > Co), compared to the transition metals

  9. Second international round robin for the quantification of serum non-transferrin-bound iron and labile plasma iron in patients with iron-overload disorders.

    PubMed

    de Swart, Louise; Hendriks, Jan C M; van der Vorm, Lisa N; Cabantchik, Z Ioav; Evans, Patricia J; Hod, Eldad A; Brittenham, Gary M; Furman, Yael; Wojczyk, Boguslaw; Janssen, Mirian C H; Porter, John B; Mattijssen, Vera E J M; Biemond, Bart J; MacKenzie, Marius A; Origa, Raffaella; Galanello, Renzo; Hider, Robert C; Swinkels, Dorine W

    2016-01-01

    Non-transferrin-bound iron and its labile (redox active) plasma iron component are thought to be potentially toxic forms of iron originally identified in the serum of patients with iron overload. We compared ten worldwide leading assays (6 for non-transferrin-bound iron and 4 for labile plasma iron) as part of an international inter-laboratory study. Serum samples from 60 patients with four different iron-overload disorders in various treatment phases were coded and sent in duplicate for analysis to five different laboratories worldwide. Some laboratories provided multiple assays. Overall, highest assay levels were observed for patients with untreated hereditary hemochromatosis and β-thalassemia intermedia, patients with transfusion-dependent myelodysplastic syndromes and patients with transfusion-dependent and chelated β-thalassemia major. Absolute levels differed considerably between assays and were lower for labile plasma iron than for non-transferrin-bound iron. Four assays also reported negative values. Assays were reproducible with high between-sample and low within-sample variation. Assays correlated and correlations were highest within the group of non-transferrin-bound iron assays and within that of labile plasma iron assays. Increased transferrin saturation, but not ferritin, was a good indicator of the presence of forms of circulating non-transferrin-bound iron. The possibility of using non-transferrin-bound iron and labile plasma iron measures as clinical indicators of overt iron overload and/or of treatment efficacy would largely depend on the rigorous validation and standardization of assays.

  10. Unifying soil respiration pulses, inhibition, and temperature hysteresis through dynamics of labile soil carbon and O2

    NASA Astrophysics Data System (ADS)

    Oikawa, P. Y.; Grantz, D. A.; Chatterjee, A.; Eberwein, J. E.; Allsman, L. A.; Jenerette, G. D.

    2014-04-01

    Event-driven and diel dynamics of soil respiration (Rs) strongly influence terrestrial carbon (C) emissions and are difficult to predict. Wetting events may cause a large pulse or strong inhibition of Rs. Complex diel dynamics include hysteresis in the relationship between Rs and soil temperature. The mechanistic basis for these dynamics is not well understood, resulting in large discrepancies between predicted and observed Rs. We present a unifying approach for interpreting these phenomena in a hot arid agricultural environment. We performed a whole ecosystem wetting experiment with continuous measurement of Rs to study pulse responses to wetting in a heterotrophic system. We also investigated Rs during cultivation of Sorghum bicolor to evaluate the role of photosynthetic C in the regulation of diel variation in Rs. Finally, we adapted a Rs model with sensitivity to soil O2 and water content by incorporating two soil C pools differing in lability. We observed a large wetting-induced pulse of Rs from the fallow field and were able to accurately simulate the pulse via release of labile soil C. During the exponential phase of plant growth, Rs was inhibited in response to wetting, which was accurately simulated through depletion of soil O2. Without plants, hysteresis was not observed; however, with growing plants, an increasingly significant counterclockwise hysteresis developed. Hysteresis was simulated via a dynamic photosynthetic C pool and was not likely controlled by physical processes. These results help characterize the complex regulation of Rs and improve understanding of these phenomena under warmer and more variable conditions.

  11. Direct visualization by cryo-EM of the mycobacterial capsular layer: a labile structure containing ESX-1-secreted proteins.

    PubMed

    Sani, Musa; Houben, Edith N G; Geurtsen, Jeroen; Pierson, Jason; de Punder, Karin; van Zon, Maaike; Wever, Brigitte; Piersma, Sander R; Jiménez, Connie R; Daffé, Mamadou; Appelmelk, Ben J; Bitter, Wilbert; van der Wel, Nicole; Peters, Peter J

    2010-03-05

    The cell envelope of mycobacteria, a group of Gram positive bacteria, is composed of a plasma membrane and a Gram-negative-like outer membrane containing mycolic acids. In addition, the surface of the mycobacteria is coated with an ill-characterized layer of extractable, non-covalently linked glycans, lipids and proteins, collectively known as the capsule, whose occurrence is a matter of debate. By using plunge freezing cryo-electron microscopy technique, we were able to show that pathogenic mycobacteria produce a thick capsule, only present when the cells were grown under unperturbed conditions and easily removed by mild detergents. This detergent-labile capsule layer contains arabinomannan, alpha-glucan and oligomannosyl-capped glycolipids. Further immunogenic and proteomic analyses revealed that Mycobacterium marinum capsule contains high amounts of proteins that are secreted via the ESX-1 pathway. Finally, cell infection experiments demonstrated the importance of the capsule for binding to cells and dampening of pro-inflammatory cytokine response. Together, these results show a direct visualization of the mycobacterial capsular layer as a labile structure that contains ESX-1-secreted proteins.

  12. Forms and Lability of Phosphorus in Algae and Aquatic Macrophytes Characterized by Solution 31P NMR Coupled with Enzymatic Hydrolysis

    NASA Astrophysics Data System (ADS)

    Feng, Weiying; Zhu, Yuanrong; Wu, Fengchang; He, Zhongqi; Zhang, Chen; Giesy, John P.

    2016-11-01

    Solution Phosphorus-31 nuclear magnetic resonance (31P NMR) spectroscopy coupled with enzymatic hydrolysis (EH) with commercially available phosphatases was used to characterize phosphorus (P) compounds in extracts of the dominant aquatic macrophytes and algae in a eutrophic lake. Total extractable organic P (Po) concentrations ranged from 504 to 1643 mg kg‑1 and 2318 to 8395 mg kg‑1 for aquatic macrophytes and algae, respectively. Using 31P NMR spectroscopy, 11 Po species were detected in the mono- and diester region. Additionally, orthophosphate, pyrophosphate and phosphonates were also detected. Using EH, phytate-like P was identified as the prevalent class of enzyme-labile Po, followed by labile monoester- and diester-P. Comparison of the NMR and EH data indicated that the distribution pattern of major P forms in the samples determined by the two methods was similar (r = 0.712, p < 0.05). Additional 31P NMR spectroscopic analysis of extracts following EH showed significant decreases in the monoester and pyrophosphate regions, with a corresponding increase in the orthophosphate signal, as compared to unhydrolyzed extracts. Based on these quantity and hydrolysis data, we proposed that recycling of Po in vegetative biomass residues is an important mechanism for long-term self-regulation of available P for algal blooming in eutrophic lakes.

  13. Labile pyrogenic dissolved organic carbon in major Siberian Arctic rivers: Implications for wildfire-stream metabolic linkages

    NASA Astrophysics Data System (ADS)

    Myers-Pigg, Allison N.; Louchouarn, Patrick; Amon, Rainer M. W.; Prokushkin, Anatoly; Pierce, Kayce; Rubtsov, Alexey

    2015-01-01

    burning produces a spectrum of thermally altered materials that releases pyrogenic carbon (PyC) to terrestrial, atmospheric, and aquatic systems. Most studies focus on the refractory end of the PyC spectrum, derived from middle- to high-temperature combustion. Low-temperature PyC is produced during wildfires and has been found to be particularly labile and water soluble. Here we find that in each of the major Siberian watersheds, low-temperature fire-derived biomarkers are present in detectable concentrations during all flow regimes of the 2004-2006 sampling period, confirming that PyC is an intrinsic component of the dissolved organic carbon (DOC) pool mobilized by hydrologic events. Gymnosperm combustion, from the southern portions of these watersheds, is the primary source of this Py-DOC input. Using first-order degradation rates and transit times of water through these rivers, about half of the total estimated flux of this material may be remineralized during transport from fire source to river mouth (20-40 days), demonstrating the input of a labile source of PyC to these watersheds.

  14. [Effects of land use and abandonment on soil labile organic carbon in the Karst region of southwest China].

    PubMed

    Liao, Hong-Kai; Li, Juan; Long, Jian; Zhang, Wen-Juan; Liu, Ling-Fei

    2014-01-01

    Effects of land use and land abandonment on labile organic carbon (LOC) in whole soils and different aggregate sizes were studied by sampling analysis of the soils in some typical land uses of the Karst region, southwest China. Results showed that the content and degree of dispersion of labile organic carbon decreased with soil depth, and the content of LOC was highly significant (P < 0.01) in 0-10 cm than in 10-20 cm and 20-30 cm. In the 0-10 cm soil layer, the content of LOC distribution in different aggregates was higher in the < 0.25 mm size, while no obvious changes of LOC among aggregates were found in the 10-20 cm and 20-30 cm depths. In different land use patterns, the LOC was the highest in paddy whether in whole soils or aggregates, followed by shrub, and the lowest in abandoned 3 years grassland. Within-between principal component analysis showed that the accumulation characters between land use and LOC were in the order of paddy > shrub > abandoned 15 years grassland = dry land > abandoned 3 years grassland, the content of LOC increased by 20.3% as compared to dryland, and had reached 80% of the content of shrub in abandoned 15 years grassland at the 0-10 cm depth, indicating that at the early stage of land abandonment, the natural recovery of carbon is relatively slow, while with the abandonment time increase, the carbon sink effect gradually appear.

  15. Forms and Lability of Phosphorus in Algae and Aquatic Macrophytes Characterized by Solution 31P NMR Coupled with Enzymatic Hydrolysis

    PubMed Central

    Feng, Weiying; Zhu, Yuanrong; Wu, Fengchang; He, Zhongqi; Zhang, Chen; Giesy, John P.

    2016-01-01

    Solution Phosphorus-31 nuclear magnetic resonance (31P NMR) spectroscopy coupled with enzymatic hydrolysis (EH) with commercially available phosphatases was used to characterize phosphorus (P) compounds in extracts of the dominant aquatic macrophytes and algae in a eutrophic lake. Total extractable organic P (Po) concentrations ranged from 504 to 1643 mg kg−1 and 2318 to 8395 mg kg−1 for aquatic macrophytes and algae, respectively. Using 31P NMR spectroscopy, 11 Po species were detected in the mono- and diester region. Additionally, orthophosphate, pyrophosphate and phosphonates were also detected. Using EH, phytate-like P was identified as the prevalent class of enzyme-labile Po, followed by labile monoester- and diester-P. Comparison of the NMR and EH data indicated that the distribution pattern of major P forms in the samples determined by the two methods was similar (r = 0.712, p < 0.05). Additional 31P NMR spectroscopic analysis of extracts following EH showed significant decreases in the monoester and pyrophosphate regions, with a corresponding increase in the orthophosphate signal, as compared to unhydrolyzed extracts. Based on these quantity and hydrolysis data, we proposed that recycling of Po in vegetative biomass residues is an important mechanism for long-term self-regulation of available P for algal blooming in eutrophic lakes. PMID:27849040

  16. Argon direct analysis in real time mass spectrometry in conjunction with makeup solvents: a method for analysis of labile compounds.

    PubMed

    Yang, Hongmei; Wan, Debin; Song, Fengrui; Liu, Zhiqiang; Liu, Shuying

    2013-02-05

    Helium direct analysis in real time (He-DART) mass spectrometry (MS) analysis of labile compounds usually tends to be challenging because of the occurrence of prominent fragmentation, which obscures the assigning of an ion to an independent species or merely a fragment in a mixture. In the present work, argon DART (Ar-DART) MS in conjunction with makeup solvents has been demonstrated to analyze a variety of labile compounds including nucleosides, alkaloids, glucose, and other small molecules. The results presented here confirm that Ar-DART can generate significantly less energetic ions than conventional He-DART and is able to produce the intact molecular ions with little or no fragmentation in both positive and negative ion modes. Adding a makeup solvent (absolute ethyl alcohol, methanol, fluorobenzene, or acetone) to the argon gas stream at the exit of the DART ion source can result in 1-2 orders of magnitude increase in detection signals. The sensitivity attainable by Ar-DART was found to be comparable to that by He-DART. The investigation of influence of solvents improves our understanding of the fundamental desorption and ionization processes in DART. The practical application of this rapid and high throughput method is demonstrated by the successful analysis of a natural product (Crude Kusnezoff Monkshood) extract, demonstrating the great potential in mixture research.

  17. Rapid and nondestructive measurement of labile Mn, Cu, Zn, Pb and As in DGT by using field portable-XRF.

    PubMed

    Chen, Zheng; Williams, Paul N; Zhang, Hao

    2013-09-01

    The technique of diffusive gradients in thin films (DGT) is often employed to quantify labile metals in situ; however, it is a challenge to perform the measurements in-field. This study evaluated the capability of field-portable X-ray fluorescence (FP-XRF) to swiftly generate elemental speciation information with DGT. Biologically available metal ions in environmental samples passively preconcentrate in the thin films of DGT devices, providing an ideal and uniform matrix for XRF nondestructive detection. Strong correlation coefficients (r > 0.992 for Mn, Cu, Zn, Pb and As) were obtained for all elements during calibration. The limits of quantitation (LOQ) for the investigated elements of FP-XRF on DGT devices are 2.74 for Mn, 4.89 for Cu, 2.89 for Zn, 2.55 for Pb, and 0.48 for As (unit: μg cm(-2)). When Pb and As co-existed in the solution trials, As did not interfere with Pb detection when using Chelex-DGT. However, there was a significant enhancement of the Pb reading attributed to As when ferrihydrite binding gels were tested, consistent with Fe-oxyhydroxide surfaces absorbing large quantities of As. This study demonstrates the value of the FP-XRF technique to rapidly and nondestructively detect the metals accumulated in DGT devices, providing a new and simple diagnostic tool for on-site environmental monitoring of labile metals/metalloids.

  18. Effect of fractions of Ethiopian And Norwegian colostrum on rotavirus and Escherichia coli heat-labile enterotoxin.

    PubMed Central

    Otnaess, A B; Orstavik, I

    1981-01-01

    Samples of colostrum from both Ethiopian and Norwegian women contained antirotavirus activities of immunoglobulin and non-immunoglobulin nature. No significant differences in rotavirus immunoglobulin A or in rotavirus-inhibiting activity were found between samples from the two countries. The non-immunoglobulin inhibitory activity was trypsin sensitive and heat stable (100 degrees C for 10 min). Escherichia coli heat-labile enterotoxin antibodies were measured in the colostrum samples by enzyme-linked immunosorbent assay. No E. coli enterotoxin-specific immunoglobulin A was detected, possibly due to the high background caused by the nonspecific adsorption of immunoglobulin A to the enzyme-linked immunosorbent assay plates in the absence of toxin. A total of 5 of 15 Ethiopian colostrum samples and 0 of 11 Norwegian colostrum samples neutralized the effect of E. coli heat-labile enterotoxin on YI adrenal cells. Both the Ethiopian and the Norwegian colostrum samples contained a non-immunoglobulin enterotoxin-inhibitory activity when the toxin was measured by enzyme-linked immunosorbent assay. This inhibitory activity was not trypsin sensitive, and extraction by chloroform-methanol indicated that the inhibitor was of a lipid nature. PMID:6268544

  19. Field method for rapid quantification of labile organic carbon in hyper-arid desert soils validated by two thermal methods

    NASA Astrophysics Data System (ADS)

    Fletcher, Lauren E.; Valdivia-Silva, Julio E.; Perez-Montaño, Saul; Condori-Apaza, Renee M.; Conley, Catharine A.; Navarro-Gonzalez, Rafael; McKay, Christopher P.

    2014-03-01

    The objective of this work was to develop a field method for the determination of labile organic carbon in hyper-arid desert soils. Industry standard methods rely on expensive analytical equipment that are not possible to take into the field, while scientific challenges require fast turn-around of large numbers of samples in order to characterize the soils throughout this region. Here we present a method utilizing acid-hydrolysis extraction of the labile fraction of organic carbon followed by potassium permanganate oxidation, which provides a quick and inexpensive approach to investigate samples in the field. Strict reagent standardization and calibration steps within this method allowed the determination of very low levels of organic carbon in hyper-arid soils, in particular, with results similar to those determined by the alternative methods of Calcination and Pyrolysis-Gas Chromatography-Mass Spectrometry. Field testing of this protocol increased the understanding of the role of organic materials in hyper-arid environments and allowed real-time, strategic decision making for planning for more detailed laboratory-based analysis.

  20. Sensitivity analysis of some critical factors affecting simulated intrusion volumes during a low pressure transient event in a full-scale water distribution system.

    PubMed

    Ebacher, G; Besner, M C; Clément, B; Prévost, M

    2012-09-01

    Intrusion events caused by transient low pressures may result in the contamination of a water distribution system (DS). This work aims at estimating the range of potential intrusion volumes that could result from a real downsurge event caused by a momentary pump shutdown. A model calibrated with transient low pressure recordings was used to simulate total intrusion volumes through leakage orifices and submerged air vacuum valves (AVVs). Four critical factors influencing intrusion volumes were varied: the external head of (untreated) water on leakage orifices, the external head of (untreated) water on submerged air vacuum valves, the leakage rate, and the diameter of AVVs' outlet orifice (represented by a multiplicative factor). Leakage orifices' head and AVVs' orifice head levels were assessed through fieldwork. Two sets of runs were generated as part of two statistically designed experiments. A first set of 81 runs was based on a complete factorial design in which each factor was varied over 3 levels. A second set of 40 runs was based on a latin hypercube design, better suited for experimental runs on a computer model. The simulations were conducted using commercially available transient analysis software. Responses, measured by total intrusion volumes, ranged from 10 to 366 L. A second degree polynomial was used to analyze the total intrusion volumes. Sensitivity analyses of both designs revealed that the relationship between the total intrusion volume and the four contributing factors is not monotonic, with the AVVs' orifice head being the most influential factor. When intrusion through both pathways occurs concurrently, interactions between the intrusion flows through leakage orifices and submerged AVVs influence intrusion volumes. When only intrusion through leakage orifices is considered, the total intrusion volume is more largely influenced by the leakage rate than by the leakage orifices' head. The latter mainly impacts the extent of the area affected by

  1. Generation of a Genome Scale Lentiviral Vector Library for EF1α Promoter-Driven Expression of Human ORFs and Identification of Human Genes Affecting Viral Titer

    PubMed Central

    Škalamera, Dubravka; Dahmer, Mareike; Purdon, Amy S.; Wilson, Benjamin M.; Ranall, Max V.; Blumenthal, Antje; Gabrielli, Brian; Gonda, Thomas J.

    2012-01-01

    The bottleneck in elucidating gene function through high-throughput gain-of-function genome screening is the limited availability of comprehensive libraries for gene overexpression. Lentiviral vectors are the most versatile and widely used vehicles for gene expression in mammalian cells. Lentiviral supernatant libraries for genome screening are commonly generated in the HEK293T cell line, yet very little is known about the effect of introduced sequences on the produced viral titer, which we have shown to be gene dependent. We have generated an arrayed lentiviral vector library for the expression of 17,030 human proteins by using the GATEWAY® cloning system to transfer ORFs from the Mammalian Gene Collection into an EF1alpha promoter-dependent lentiviral expression vector. This promoter was chosen instead of the more potent and widely used CMV promoter, because it is less prone to silencing and provides more stable long term expression. The arrayed lentiviral clones were used to generate viral supernatant by packaging in the HEK293T cell line. The efficiency of transfection and virus production was estimated by measuring the fluorescence of IRES driven GFP, co-expressed with the ORFs. More than 90% of cloned ORFs produced sufficient virus for downstream screening applications. We identified genes which consistently produced very high or very low viral titer. Supernatants from select clones that were either high or low virus producers were tested on a range of cell lines. Some of the low virus producers, including two previously uncharacterized proteins were cytotoxic to HEK293T cells. The library we have constructed presents a powerful resource for high-throughput gain-of-function screening of the human genome and drug-target discovery. Identification of human genes that affect lentivirus production may lead to improved technology for gene expression using lentiviral vectors. PMID:23251614

  2. A Double Blind Trial of Divalproex Sodium for Affective Liability and Alcohol Use Following Traumatic Brain Injury

    DTIC Science & Technology

    2016-01-01

    Award Number: W81XWH-08-2-0652 TITLE: A Double Blind Trial of Divalproex Sodium for Affective Liability and Alcohol Use Following Traumatic Brain...of Divalproex Sodium for Affective Liability and Alcohol Use Following Traumatic Brain Injury 5b. GRANT NUMBER PT075168 5c. PROGRAM ELEMENT...expressed as affective lability, will decrease significantly in TBI subjects treated with divalproex sodium , a mood stabilizing medication, as

  3. Assessment of toxic metals in groundwater and saliva in an arsenic affected area of West Bengal, India: A pilot scale study.

    PubMed

    Bhowmick, Subhamoy; Kundu, Amit Kumar; Adhikari, Jishnu; Chatterjee, Debankur; Iglesias, Monica; Nriagu, Jerome; Guha Mazumder, Debendra Nath; Shomar, Basem; Chatterjee, Debashis

    2015-10-01

    affected communities.

  4. Emotion Socialization in the Context of Risk and Psychopathology: Maternal Emotion Coaching Predicts Better Treatment Outcomes for Emotionally Labile Children with Oppositional Defiant Disorder

    PubMed Central

    Dunsmore, Julie C.; Booker, Jordan A.; Ollendick, Thomas H.; Greene, Ross W.

    2015-01-01

    We examined whether maternal emotion coaching at pre-treatment predicted children's treatment response following a 12-week program addressing children's Oppositional Defiant Disorder (ODD) symptoms. Eighty-nine mother-child dyads participated. At pre-treatment, mothers and children engaged in an emotion talk task. Mothers also reported their beliefs about emotions at pre-treatment and their child's disruptive behavior symptoms, emotion regulation, and emotion lability/negativity at pre-, mid-, and post-treatment. Clinicians reported children's symptom severity at pre- and post-treatment. Children's emotion lability/negativity moderated effects of maternal emotion coaching on children's post-treatment ODD symptoms, with stronger benefits of emotion coaching for children high in emotion lability/negativity. Results suggest that emotion coaching may promote treatment response for children with ODD who are especially at risk due to their emotionality. PMID:26848211

  5. Distribution of dissolved labile and particulate iron and copper in Terra Nova Bay polynya (Ross Sea, Antarctica) surface waters in relation to nutrients and phytoplankton growth

    NASA Astrophysics Data System (ADS)

    Rivaro, Paola; Ianni, Carmela; Massolo, Serena; Abelmoschi, M. Luisa; De Vittor, Cinzia; Frache, Roberto

    2011-05-01

    The distribution of the dissolved labile and of the particulate Fe and Cu together with dissolved oxygen, nutrients, chlorophyll a and total particulate matter was investigated in the surface waters of Terra Nova Bay polynya in mid-January 2003. The measurements were conducted within the framework of the Italian Climatic Long-term Interactions of the Mass balance in Antarctica (CLIMA) Project activities. The labile dissolved fraction was operationally defined by employing the chelating resin Chelex-100, which retains free and loosely bound trace metal species. The dissolved labile Fe ranges from below the detection limit (0.15 nM) to 3.71 nM, while the dissolved labile Cu from below the detection limit (0.10 nM) to 0.90 nM. The lowest concentrations for both metals were observed at 20 m depth (the shallowest depth for which metals were measured). The concentration of the particulate Fe was about 5 times higher than the dissolved Fe concentration, ranging from 0.56 to 24.83 nM with an average of 6.45 nM. The concentration of the particulate Cu ranged from 0.01 to 0.71 nM with an average of 0.17 nM. The values are in agreement with the previous data collected in the same area. We evaluated the role of the Fe and Cu as biolimiting metals. The N:dissolved labile Fe ratios (18,900-130,666) would or would not allow a complete nitrate removal, on the basis of the N:Fe requirement ratios that we calculated considering the N:P and the C:P ratios estimated for diatoms. This finding partially agrees with the Si:N ratio that we found (2.29). Moreover we considered a possible influence of the dissolved labile Cu on the Fe uptake process.

  6. Development of a vaccine of cross-linked heat-stable and heat-labile enterotoxins that protects against Escherichia coli producing either enterotoxin.

    PubMed Central

    Klipstein, F A; Engert, R F; Clements, J D

    1982-01-01

    A vaccine of cross-linked heat-stable (ST) and heat-labile (LT) toxins that protects against heterologous serotypes of strains of Escherichia coli which produce either the LT or ST enterotoxin was developed by conjugating ST to LT by the carbodiimide reaction. Three interrelated factors were found to affect the composition and properties of the final conjugate: (i) the amount of carbodiimide added to the toxins, (ii) the initial ratio of ST to LT, and (iii) the duration of the conjugation reaction. Optimal conjugation conditions were identified as a carbodiimide-to-toxin ratio of 10:1 by weight, an initial molar ratio of ST to LT of 100:1, and a conjugation reaction time of 96 h. This approach yielded a conjugate that contained 96% by moles and 36% by weight pure ST, determined with radioiodinated pure ST, and 34% by weight semi-pure ST, determined by the Lowry protein method. The retained antigenicities of the conjugated toxins, as determined by enzyme-linked immunosorbent assays, was greater than or equal to 82%, and their toxicities, as determined by the Y1 adrenal cell assay for LT and by the suckling mouse assay for ST, were reduced to less than or equal to 0.15%. Immunization of rats with this cross-linked ST-LT vaccine provided strong protection against challenge with either the LT or the ST toxin or with viable heterologous strains which produce these toxins, either singly or together. These observations indicate that conjugation of ST to LT results in a unique new immunogen in that ST acquires immunogenicity as a function of the reaction, LT retains most of its antigenicity, and the toxic properties of each individual toxin are greatly reduced. PMID:6749682

  7. [Effects of the different land use on soil labile organic matter and carbon management index in Junyun Mountain].

    PubMed

    Xu, Peng; Jiang, Chang-Sheng; Hao, Qing-Ju; Zhu, Tao

    2013-10-01

    The impacts of different land use on soil organic matter (SOM), soil labile organic matter (SLOM) and their efficiency ratios (ER), and soil carbon management index (CMI) were studied in this study. Subtropical evergreen broad-leaved forest (abbreviation: forest) , sloping farmland, orchard and abandoned land were selected and soils at the depths of 0-10, 10-20, 20-30, 30-40, 40-50 and 50-60 cm were sampled in the spring of 2011 to determine the contents of soil organic matter and labile organic matter. The results showed that the contents of soil organic matter and soil labile organic matter both decreased with the increase of soil depth under all four land use types; however, forest and orchard enriched SOM and SLOM contents in the 0-10 cm and 0-20 cm soil layers, respectively, while the contents of SOM and SLOM decreased evenly in sloping farmland and abandoned land. In the whole soil layer (0-60 cm) , the order of SOM and SLOM contents was abandoned land > forest > orchard > sloping farmland, indicating that at the conversion from forest into orchard or sloping farmland, SOM was reduced by 21.56% (P >0.05) and 55.90% (P <0.05), respectively, and at the conversion from sloping farmland into abandoned land, the low SLOM, middle SLOM and high SLOM increased by 144.2% (P<0.05) , 153.3% (P <0.05) and 242.7% (P <0.05), respectively. There was no significant difference in low ER, middle ER and high ER among the four land uses as suggested by ANOVA which showed that SRs were not sensible to the change of land use. All three CMis were in the order of abandoned land > forest > orchard > sloping farmland, revealing that forest reclamation resulted in the reduction of soil organic carbon storage and the decline of soil quality, and the abandonment of sloping farmland would increase soil carbon sink and improve soil quality. Three kinds of SLOM were all positively correlated with soil total nitrogen, available phosphorus and available potassium, while negatively correlated

  8. Stability and Lability in Science Interest from Middle Schools to the Age of Science Choices (14+).

    ERIC Educational Resources Information Center

    Bottomley, Jennifer; Ormerod, M. B.

    1981-01-01

    Investigated factors affecting science interests of 592 students by administering three questionnaires to them at ages 12+, 13+, and 14+. Conclusions drawn from numerous findings suggest that early science activities have positive and negative long-term effects and dealing with animals seems detrimental to some females' future interest in biology.…

  9. Molecular glass positive i-line photoresist materials containing 2,1,4-DNQ and acid labile group

    NASA Astrophysics Data System (ADS)

    Wang, Liyuan; Yu, Jinxing; Xu, Na

    2010-04-01

    Recent years increasing attention has been given to molecular glass resist materials. In this paper, maleopimaric acid, cycloaddition reaction product of rosin with maleic anhydride, was reacted with hydroxylamine and then further esterified with 2-diazo-1-naphthoquinone-4-sulfonyl chloride to give N-hydroxy maleopimarimide sulfonate. The carboxylic acid group of the compound was then protected by the reaction of this compound with vinyl ethyl ether or dihydropyran. Thus obtained compounds were amorphous. When irradiated with i-line light, the 2,1,4-DNQ group undergo photolysis not only to give off nitrogen gas but also generate sulfonic acid which can result in the decomposition of the acid labile group. So, a novel chemically amplified positive i-line molecular glass photoresists can be formed by the compound and other acidolytic molecular glass compounds. The lithographic performance of the resist materials is evaluated.

  10. Comparison of two experimental speciation methods with a theoretical approach to monitor free and labile Cd fractions in soil solutions.

    PubMed

    Parat, C; Cornu, J-Y; Schneider, A; Authier, L; Sapin-Didier, V; Denaix, L; Potin-Gautier, M

    2009-08-26

    This work focused on the suitability of two techniques to monitor cadmium speciation in soil solutions collected during a 7-day incubation of a contaminated soil. Anodic stripping voltammetry (ASV) and ion exchange were performed on soil solutions collected daily and results were compared with calculations obtained with the speciation software Visual MINTEQ. The electrochemically labile Cd fraction was greater than the exchange-estimated free Cd fraction during the first 6 days, after which it decreased sharply during the last 2 days to reach values close to the exchange-estimated free Cd fraction. Further investigations showed that the increase in pH was mainly responsible for the reduction. However, calculations performed with Visual MINTEQ software clearly demonstrated that a change in the nature of organic matter and/or its complexing capacity also needed to be taken into consideration.

  11. Scales, scales and more scales.

    PubMed

    Weitzenhoffer, Andre M

    2002-01-01

    This article examines the nature, uses, and limitations of the large variety of existing, so-called, hypnosis scales; that is, instruments that have been proposed for the assessment of hypnotic behavior. Although the major aim of most of the scales ostensively seems to be to assess several aspects of hypnotic states, they are found generally to say little about these and much more about responses to suggestions. The greatest application of these scales is to be found in research, but they also have a limited place in clinical work.

  12. Affective Induction and Creative Thinking

    ERIC Educational Resources Information Center

    Fernández-Abascal, Enrique G.; Díaz, María D. Martín

    2013-01-01

    Three studies explored the relation between affect and production of creative divergent thinking, assessed with the Torrance Tests of Creative Thinking (Figural TTCT). In the first study, general, positive, and negative affect, assessed with the Positive and Negative Affect Scale (PANAS) were compared with creative production. In the second study,…

  13. Quantitative chemical exchange saturation transfer (qCEST) MRI - RF spillover effect-corrected omega plot for simultaneous determination of labile proton fraction ratio and exchange rate

    PubMed Central

    Sun, Phillip Zhe; Wang, Yu; Dai, ZhuoZhi; Xiao, Gang; Wu, Renhua

    2014-01-01

    Chemical exchange saturation transfer (CEST) MRI is sensitive to dilute proteins and peptides as well as microenvironmental properties. However, the complexity of the CEST MRI effect, which varies with the labile proton content, exchange rate and experimental conditions, underscores the need for development of quantitative CEST (qCEST) analysis. Towards this goal, it has been shown that the omega plot is capable of quantifying paramagnetic CEST (PARACEST) MRI. However, the use of omega plot is somewhat limited for diamagnetic CEST (DIACEST) MRI because it is more susceptible to direct RF saturation (spillover) effects owing to their relatively small chemical shift. Recently, it has been found that for dilute DIACEST agents that undergo slow to intermediate chemical exchange, the RF spillover effect varies little with the labile proton ratio and exchange rate. Therefore, we postulated that the omega plot analysis can be improved if RF spillover effect could be estimated and taken into account. Specifically, simulation showed that both labile proton ratio and exchange rate derived using the spillover effect-corrected omega plot are in good agreement with simulated values. In addition, the modified omega plot was confirmed experimentally, and we showed that the derived labile proton ratio increases linearly with creatine concentration (P< 0.01), with little difference in their exchange rate (P=0.32). In summary, our study extended the conventional omega plot for quantitative analysis of DIACEST MRI. PMID:24706610

  14. Quantitative chemical exchange saturation transfer (qCEST) MRI--RF spillover effect-corrected omega plot for simultaneous determination of labile proton fraction ratio and exchange rate.

    PubMed

    Sun, Phillip Zhe; Wang, Yu; Dai, ZhuoZhi; Xiao, Gang; Wu, Renhua

    2014-01-01

    Chemical exchange saturation transfer (CEST) MRI is sensitive to dilute proteins and peptides as well as microenvironmental properties. However, the complexity of the CEST MRI effect, which varies with the labile proton content, exchange rate and experimental conditions, underscores the need for developing quantitative CEST (qCEST) analysis. Towards this goal, it has been shown that omega plot is capable of quantifying paramagnetic CEST MRI. However, the use of the omega plot is somewhat limited for diamagnetic CEST (DIACEST) MRI because it is more susceptible to direct radio frequency (RF) saturation (spillover) owing to the relatively small chemical shift. Recently, it has been found that, for dilute DIACEST agents that undergo slow to intermediate chemical exchange, the spillover effect varies little with the labile proton ratio and exchange rate. Therefore, we postulated that the omega plot analysis can be improved if RF spillover effect could be estimated and taken into account. Specifically, simulation showed that both labile proton ratio and exchange rate derived using the spillover effect-corrected omega plot were in good agreement with simulated values. In addition, the modified omega plot was confirmed experimentally, and we showed that the derived labile proton ratio increased linearly with creatine concentration (p < 0.01), with little difference in their exchange rate (p = 0.32). In summary, our study extends the conventional omega plot for quantitative analysis of DIACEST MRI.

  15. EFFECTS OF CLIMATE CHANGE ON LABILE AND STRUCTURAL CARBON IN DOUGLAS-FIR NEEDLES AS ESTIMATED BY DELTA 13C AND C AREA MEASUREMENTS

    EPA Science Inventory

    Isotopic measurements may provide new insights into levels in leaves of labile and structural carbon (C) under climate change. In a 4-year climate change experiment using Pseudotsuga menziesii (Douglas-fir) seedlings and a 2x2 factorial design in enclosed chambers (n=3), atmosph...

  16. Evaluation of heat-labile enterotoxins type IIa and type IIb in the pathogenicity of enterotoxigenic Escherichia coli for neonatal pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Type II heat-labile enterotoxins (LT-II) have been reported in Escherichia coli isolates from humans, animals, food and water samples. The roles of the antigenically distinguishable LT-IIa and LT-IIb subtypes in pathogenesis and virulence of enterotoxigenic E. coli (ETEC) have not been previously re...

  17. Simultaneous experimental determination of labile proton fraction ratio and exchange rate with irradiation radio frequency power-dependent quantitative CEST MRI analysis.

    PubMed

    Sun, Phillip Zhe; Wang, Yu; Xiao, Gang; Wu, Renhua

    2013-01-01

    Chemical exchange saturation transfer (CEST) imaging is sensitive to dilute proteins/peptides and microenvironmental properties, and has been increasingly evaluated for molecular imaging and in vivo applications. However, the experimentally measured CEST effect depends on the CEST agent concentration, exchange rate and relaxation time. In addition, there may be non-negligible direct radio-frequency (RF) saturation effects, particularly severe for diamagnetic CEST (DIACEST) agents owing to their relatively small chemical shift difference from that of the bulk water resonance. As such, the commonly used asymmetry analysis only provides CEST-weighted information. Recently, it has been shown with numerical simulation that both labile proton concentration and exchange rate can be determined by evaluating the RF power dependence of DIACEST effect. To validate the simulation results, we prepared and imaged two CEST phantoms: a pH phantom of serially titrated pH at a fixed creatine concentration and a concentration phantom of serially varied creatine concentration titrated to the same pH, and solved the labile proton fraction ratio and exchange rate per-pixel. For the concentration phantom, we showed that the labile proton fraction ratio is proportional to the CEST agent concentration with negligible change in the exchange rate. Additionally, we found the exchange rate of the pH phantom is dominantly base-catalyzed with little difference in the labile proton fraction ratio. In summary, our study demonstrated quantitative DIACEST MRI, which remains promising to augment the conventional CEST-weighted MRI analysis.

  18. Labile pools of Pb in vegetable-growing soils investigated by an isotope dilution method and its influence on soil pH.

    PubMed

    Xie, Hong; Huang, Zhi-Yong; Cao, Ying-Lan; Cai, Chao; Zeng, Xiang-Cheng; Li, Jian

    2012-08-01

    Pollution of Pb in the surface of agricultural soils is of increasing concern due to its serious impact on the plant growth and the human health through the food chain. However, the mobility, activity and bioavailability of Pb rely mainly on its various chemical species in soils. In the present study, E and L values, the labile pools of isotopically exchangeable Pb, were estimated using the method of isotope dilution in three vegetable-growing soils. The experiments involved adding a stable enriched isotope ((206)Pb > 96%) to a soil suspension and to soils in which plants are subsequently grown, the labile pools of Pb were then estimated by measuring the isotopic composition of Pb in soil solutions and in the plant tissues, respectively. In addition, the correlation of E values and soil pH was investigated at the ranges of pH 4.5-7.0. The amount of labile Pb in soils was also estimated using different single chemical extractants and a modified BCR approach. The results showed that after spiking the enriched isotopes of (206)Pb (>96%) for 24 hours an equilibration of isotopic exchanges in soil suspensions was achieved, and the isotope ratios of (208)Pb/(206)Pb measured at that time was used for calculating the E(24 h) values. The labile pools of Pb by %E(24 h) values, ranging from 53.2% to 61.7% with an average 57%, were found to be significantly higher (p < 0.05) than the values estimated with L values, single chemical extractants and the Σ(BCR) values obtained with the BCR approach, respectively. A strong negative correlation (R(2) = 0.984) between E(24 h) values and soil pH was found in the tested soil sample. The results indicate that the %E(24 h) value can more rapidly and easily predict the labile pools of Pb in soils compared with L values, but it might be readily overestimated because of the artificial soil acidity derived from the spiked isotopic tracer and the excess of spiked enriched isotopes. The results also suggest that the amounts of Pb extracted

  19. Anti-plasmodial activity of aroylhydrazone and thiosemicarbazone iron chelators: effect on erythrocyte membrane integrity, parasite development and the intracellular labile iron pool.

    PubMed

    Walcourt, Asikiya; Kurantsin-Mills, Joseph; Kwagyan, John; Adenuga, Babafemi B; Kalinowski, Danuta S; Lovejoy, David B; Lane, Darius J R; Richardson, Des R

    2013-12-01

    Iron chelators inhibit the growth of the malaria parasite, Plasmodium falciparum, in culture and in animal and human studies. We previously reported the anti-plasmodial activity of the chelators, 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311), 2-hydroxy-1-naphthylaldehyde 4-methyl-3-thiosemicarbazone (N4mT), and 2-hydroxy-1-naphthylaldehyde 4-phenyl-3-thiosemicarbazone (N4pT). In fact, these ligands showed greater growth inhibition of chloroquine-sensitive (3D7) and chloroquine-resistant (7G8) strains of P. falciparum in culture compared to desferrioxamine (DFO). The present study examined the effects of 311, N4mT and N4pT on erythrocyte membrane integrity and asexual parasite development. While the characteristic biconcave disk shape of the erythrocytes was unaffected, the chelators caused very slight hemolysis at IC50 values that inhibited parasite growth. The chelators 311, N4mT and N4pT affected all stages of the intra-erythrocytic development cycle (IDC) of P. falciparum in culture. However, while these ligands primarily affected the ring-stage, DFO inhibited primarily trophozoite and schizont-stages. Ring, trophozoite and schizont-stages of the IDC were inhibited by significantly lower concentrations of 311, N4mT, and N4pT (IC50=4.45±1.70, 10.30±4.40, and 3.64±2.00μM, respectively) than DFO (IC50=23.43±3.40μM). Complexation of 311, N4mT and N4pT with iron reduced their anti-plasmodial activity. Estimation of the intracellular labile iron pool (LIP) in erythrocytes showed that the chelation efficacy of 311, N4mT and N4pT corresponded to their anti-plasmodial activities, suggesting that the LIP may be a potential source of non-heme iron for parasite metabolism within the erythrocyte. This study has implications for malaria chemotherapy that specifically disrupts parasite iron utilization.

  20. Assessment of affect integration: validation of the affect consciousness construct.

    PubMed

    Solbakken, Ole André; Hansen, Roger Sandvik; Havik, Odd E; Monsen, Jon T

    2011-05-01

    Affect integration, or the capacity to utilize the motivational and signal properties of affect for personal adjustment, is assumed to be an important aspect of psychological health and functioning. Affect integration has been operationalized through the affect consciousness (AC) construct as degrees of awareness, tolerance, nonverbal expression, and conceptual expression of nine discrete affects. A semistructured Affect Consciousness Interview (ACI) and separate Affect Consciousness Scales (ACSs) have been developed to specifically assess these aspects of affect integration. This study explored the construct validity of AC in a Norwegian clinical sample including estimates of reliability and assessment of structure by factor analyses. External validity issues were addressed by examining the relationships between scores on the ACSs and self-rated symptom- and interpersonal problem measures as well as independent, observer-based ratings of personality disorder criteria and the Global Assessment of Functioning (GAF) scale from the Diagnostic and Statistical Manual of Mental Disorders (4th ed. [DSM-IV]; American Psychiatric Association, 1994).

  1. The early faint sun paradox: Organic shielding of ultraviolet-labile greenhouse gases

    SciTech Connect

    Sagan, C.; Chyba, C.

    1997-05-23

    Atmospheric mixing ratios of {approximately}10{sup -5 {+-}1} for ammonia on the early Earth would have been sufficient, through the resulting greenhouse warming, to counteract the temperature effects of the faint early sun. One argument against such model atmospheres has been the short time scale for ammonia photodissociation by solar ultraviolet light. Here it is shown that ultraviolet absorption by steady-state amounts of high-altitude organic solids produced from methane photolysis may have shielded ammonia sufficiently that ammonia resupply rates were able to maintain surface temperatures above freezing. 78 refs., 2 figs., 1 tab.

  2. The early faint sun paradox: organic shielding of ultraviolet-labile greenhouse gases

    NASA Technical Reports Server (NTRS)

    Sagan, C.; Chyba, C.

    1997-01-01

    Atmospheric mixing ratios of approximately 10(-5 +/- 1) for ammonia on the early Earth would have been sufficient, through the resulting greenhouse warming, to counteract the temperature effects of the faint early sun. One argument against such model atmospheres has been the short time scale for ammonia photodissociation by solar ultraviolet light. Here it is shown that ultraviolet absorption by steady-state amounts of high-altitude organic solids produced from methane photolysis may have shielded ammonia sufficiently that ammonia resupply rates were able to maintain surface temperatures above freezing.

  3. Implementation factors affecting the large-scale deployment of digital health and well-being technologies: A qualitative study of the initial phases of the 'Living-It-Up' programme.

    PubMed

    Agbakoba, Ruth; McGee-Lennon, Marilyn; Bouamrane, Matt-Mouley; Watson, Nicholas; Mair, Frances S

    2016-12-01

    Little is known about the factors which facilitate or impede the large-scale deployment of health and well-being consumer technologies. The Living-It-Up project is a large-scale digital intervention led by NHS 24, aiming to transform health and well-being services delivery throughout Scotland. We conducted a qualitative study of the factors affecting the implementation and deployment of the Living-It-Up services. We collected a range of data during the initial phase of deployment, including semi-structured interviews (N = 6); participant observation sessions (N = 5) and meetings with key stakeholders (N = 3). We used the Normalisation Process Theory as an explanatory framework to interpret the social processes at play during the initial phases of deployment.Initial findings illustrate that it is clear - and perhaps not surprising - that the size and diversity of the Living-It-Up consortium made implementation processes more complex within a 'multi-stakeholder' environment. To overcome these barriers, there is a need to clearly define roles, tasks and responsibilities among the consortium partners. Furthermore, varying levels of expectations and requirements, as well as diverse cultures and ways of working, must be effectively managed. Factors which facilitated implementation included extensive stakeholder engagement, such as co-design activities, which can contribute to an increased 'buy-in' from users in the long term. An important lesson from the Living-It-Up initiative is that attempting to co-design innovative digital services, but at the same time, recruiting large numbers of users is likely to generate conflicting implementation priorities which hinder - or at least substantially slow down - the effective rollout of services at scale.The deployment of Living-It-Up services is ongoing, but our results to date suggest that - in order to be successful - the roll-out of digital health and well-being technologies at scale requires a delicate and pragmatic trade

  4. Implementation factors affecting the large-scale deployment of digital health and well-being technologies: A qualitative study of the initial phases of the ‘Living-It-Up’ programme

    PubMed Central

    Agbakoba, Ruth; McGee-Lennon, Marilyn; Bouamrane, Matt-Mouley; Watson, Nicholas; Mair, Frances S

    2015-01-01

    Little is known about the factors which facilitate or impede the large-scale deployment of health and well-being consumer technologies. The Living-It-Up project is a large-scale digital intervention led by NHS 24, aiming to transform health and well-being services delivery throughout Scotland. We conducted a qualitative study of the factors affecting the implementation and deployment of the Living-It-Up services. We collected a range of data during the initial phase of deployment, including semi-structured interviews (N = 6); participant observation sessions (N = 5) and meetings with key stakeholders (N = 3). We used the Normalisation Process Theory as an explanatory framework to interpret the social processes at play during the initial phases of deployment. Initial findings illustrate that it is clear − and perhaps not surprising − that the size and diversity of the Living-It-Up consortium made implementation processes more complex within a ‘multi-stakeholder’ environment. To overcome these barriers, there is a need to clearly define roles, tasks and responsibilities among the consortium partners. Furthermore, varying levels of expectations and requirements, as well as diverse cultures and ways of working, must be effectively managed. Factors which facilitated implementation included extensive stakeholder engagement, such as co-design activities, which can contribute to an increased ‘buy-in’ from users in the long term. An important lesson from the Living-It-Up initiative is that attempting to co-design innovative digital services, but at the same time, recruiting large numbers of users is likely to generate conflicting implementation priorities which hinder − or at least substantially slow down − the effective rollout of services at scale. The deployment of Living-It-Up services is ongoing, but our results to date suggest that − in order to be successful − the roll-out of digital health and well-being technologies at scale requires a delicate

  5. Exploring the Relationship Between Wetland Methane Emissions and Net Ecosystem Productivity Using Experimental Shading and Labile Carbon Additions.

    NASA Astrophysics Data System (ADS)

    Owens, S.; von Fischer, J. C.

    2007-12-01

    Methane (CH4) emissions from wetlands are positively correlated with net ecosystem productivity (NEP); however the relative importance of proposed controlling mechanisms remains poorly understood. The carbon supply hypothesis suggests that recent photosynthesis contributes labile carbon substrate to methanogenic habitats, resulting in higher CH4 emissions with increases in NEP. Plant gas transport is also hypothesized to be important for conducting gases between the soil and the atmosphere. High CH4 production rates often occur in saturated wetland soils where gas diffusion is extremely slow. The aerenchymous tissues of vascular wetland plants can serve as the primary pathway for CH4 emissions from the soil to the atmosphere, while also allowing CH4 to bypass more aerobic soil regions where CH4 oxidation could occur. Using a hypothesis-driven experimental approach, we established shading treatments in a Juncus- dominated wetland in the northern Colorado Front Range, and measured CH4 and CO2 fluxes with a static chamber technique. In the summer of 2007, the shading manipulations (45% and 65% shade) significantly reduced net ecosystem exchange (NEE; an approximation of NEP) and mean CH4 fluxes compared to control plots (p=0.02 and p=0.01, respectively). To test the carbon supply hypothesis, we injected a solution containing acetate (a primary methanogenic carbon source) to a depth of 20cm below the soil surface. Acetate additions stimulated CH4 emission rates across all plots by an average of 29.3% (p=0.01). However the strength of the CH4 emission response was not significantly related to plot treatment or NEE, indicating that reduced carbon supply could not explain the response to shading. We hypothesize that reduced plant gas transport was more important than labile carbon supply for driving the lower CH4 emission rates in shaded plots. The dry weight of above-ground biomass was lower in shaded plots (p=0.04), suggesting a possible link between plant gas transport

  6. Characterization of labile organic carbon in coastal wetland soils of the Mississippi River deltaic plain: relationships to carbon functionalities.

    PubMed

    Dodla, Syam K; Wang, Jim J; Delaune, Ronald D

    2012-10-01

    Adequate characterization of labile organic carbon (LOC) is essential to the understanding of C cycling in soil. There has been very little evaluation about the nature of LOC characterizations in coastal wetlands, where soils are constantly influenced by different redox fluctuations and salt water intrusions. In this study, we characterized and compared LOC fractions in coastal wetland soils of the Mississippi River deltaic plain using four different methods including 1) aerobically mineralizable C (AMC), 2) cold water extractable C (CWEC), 3) hot water extractable C (HWEC), and 4) salt extractable C (SEC), as well as acid hydrolysable C (AHC) which includes both labile and slowly degradable organic C. Molecular organic C functional groups of these wetland soils were characterized by (13)C solid-state nuclear magnetic resonance (NMR). The LOC and AHC increased with soil organic C (SOC) regardless of wetland soil type. The LOC estimates by four different methods were positively and significantly linearly related to each other (R(2)=0.62-0.84) and with AHC (R(2)=0.47-0.71). The various LOC fractions accounted for ≤4.3% of SOC whereas AHC fraction represented 16-49% of SOC. AMC was influenced positively by O/N-alkyl and carboxyl C but negatively by alkyl C, whereas CWEC and SEC fractions were influenced only positively by carboxyl C but negatively by alkyl C in SOC. On the other hand, HWEC fraction was found to be only influenced positively by carbonyl C, and AHC positively by O/N-alkyl and alkyl C but negatively by aromatic C groups in SOC. Overall these relations suggested different contributions of various molecular organic C moieties to LOC in these wetlands from those often found for upland soils. The presence of more than 50% non-acid hydrolysable C suggested the dominance of relatively stable SOC pool that would be sequestered in these Mississippi River deltaic plain coastal wetland soils. The results have important implications to the understanding of the

  7. Is litter decomposition 'primed' by primary producer-release of labile carbon in terrestrial and aquatic experimental systems?

    NASA Astrophysics Data System (ADS)

    Soares, A. Margarida P. M.; Kritzberg, Emma S.; Rousk, Johannes

    2015-04-01

    It is possible that recalcitrant organic matter (ROM) can be 'activated' by inputs of labile organic matter (LOM) through the priming effect (PE). Investigating the PE is of major importance to fully understand the microbial use of ROM and its role on carbon (C) and nutrient cycling in both aquatic and terrestrial ecosystems. In aquatic ecosystems it is thought that the PE is triggered by periphytic algae release of LOM. Analogously, in terrestrial systems it is hypothesized that the LOM released in plant rhizospheres, or from the green crusts on the surface of agricultural soils, stimulate the activity and growth of ROM decomposers. Most previous studies on PE have utilised pulse additions of single substrates at high concentrations. However, to achieve an assessment of the true importance of the PE, it is important to simulate a realistic delivery of LOM. We investigated, in a series of 2-week laboratory experiments, how primary producer (PP)-release of LOM influence litter degradation in terrestrial and aquatic experimental systems. We used soil (terrestrial) and pond water (aquatic) microbial communities to which litter was added under light and dark conditions. In addition, glucose was added at PP delivery rates in dark treatments to test if the putative PE in light systems could be reproduced. We observed an initial peak of bacterial growth rate followed by an overall decrease over time with no treatment differences. In light treatments, periphytic algae growth and increased fungal production was stimulated when bacterial growth declined. In contrast, both fungal growth and algal production were negligible in dark treatments. This reveals a direct positive influence of photosynthesis on fungal growth. To investigate if PP LOM supplements, and the associated fungal growth, translate into a modulated litter decomposition, we are using stable isotopes to track the use of litter and algal-derived carbon by determining the δ13C in produced CO2. Fungi and bacteria

  8. [Attention deficit hyperactivity disorder in adults. Benchmarking diagnosis using the Wender-Reimherr adult rating scale].

    PubMed

    Rösler, M; Retz, W; Retz-Junginger, P; Stieglitz, R D; Kessler, H; Reimherr, F; Wender, P H

    2008-03-01

    We report on a study comparing different systems for the diagnosis of attention deficit hyperactivity disorder (ADHD) in adulthood. Recruited for evaluation were 168 patients referred to our ADHD outpatient unit. We used the Diagnostic and Statistical Manual of Mental Disorders 4th edn. (DSM-IV), International Classification of Diseases 10th edn. (ICD-10), and Utah criteria for diagnostic assessment and the Wender Utah rating scale, ADHD Self Report (ADHD-SR), and Wender Reimherr Adult Attention Deficit Disorder Rating Scale as psychopathological assessment tools. We present basic psychometric data of the Wender-Reimherr Interview (WRI). Internal consistency was determined as 0.82 (alpha). The inter-rater reliability was 1.0 (kappa coefficient) regarding ADHD diagnoses, and the ICC was 0.98 referring to the WRI total scores. The convergent validity with the ADHD-SR was 0.65 (Spearman coefficient). In 126 of 168 patients an ADHD diagnosis was made according to at least one of the three systems. The DSM-IV diagnostic set led to 119 ADHD diagnoses. As compared with the two other systems, this is about the minimum level for an ADHD diagnosis. All of the 87 ADHD diagnoses according to ICD-10 were covered by DSM-IV. The ICD-10 had no independent psychopathological items and therefore offered no additional points for the diagnostic procedure than the DSM-IV. The situation regarding Utah criteria is different. These criteria contain seven psychopathological domains: inattention, hyperactivity, disorganisation, impulsivity, affective lability, overreactivity, and hot temper. They can be assessed by use of the WRI. Ninety-three of 168 patients were diagnosed as having ADHD according to the Utah concept, which is much lower than with the DSM-IV. The particular definition of the disorder by the Utah criteria resulted in seven patients having only a Utah diagnosis but no DSM-IV diagnosis. Thus we are in a position to say that the Utah criteria have a relatively high level for

  9. Preparation of biocompatible heat-labile enterotoxin subunit B-bovine serum albumin nanoparticles for improving tumor-targeted drug delivery via heat-labile enterotoxin subunit B mediation.

    PubMed

    Zhao, Liang; Su, Rongjian; Cui, Wenyu; Shi, Yijie; Liu, Liwei; Su, Chang

    2014-01-01

    Heat-labile enterotoxin subunit B (LTB) is a non-catalytic protein from a pentameric subunit of Escherichia coli. Based on its function of binding specifically to ganglioside GM1 on the surface of cells, a novel nanoparticle (NP) composed of a mixture of bovine serum albumin (BSA) and LTB was designed for targeted delivery of 5-fluorouracil to tumor cells. BSA-LTB NPs were characterized by determination of their particle size, polydispersity, morphology, drug encapsulation efficiency, and drug release behavior in vitro. The internalization of fluorescein isothiocyanate-labeled BSA-LTB NPs into cells was observed using fluorescent imaging. Results showed that BSA-LTB NPs presented a narrow size distribution with an average hydrodynamic diameter of approximately 254±19 nm and a mean zeta potential of approximately -19.95±0.94 mV. In addition, approximately 80.1% of drug was encapsulated in NPs and released in the biphasic pattern. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that BSA-LTB NPs exhibited higher cytotoxic activity than non-targeted NPs (BSA NPs) in SMMC-7721 cells. Fluorescent imaging results proved that, compared with BSA NPs, BSA-LTB NPs could greatly enhance cellular uptake. Hence, the results indicate that BSA-LTB NPs could be a potential nanocarrier to improve targeted delivery of 5-fluorouracil to tumor cells via mediation of LTB.

  10. Hypoxia causes preservation of labile organic matter and changes seafloor microbial community composition (Black Sea).

    PubMed

    Jessen, Gerdhard L; Lichtschlag, Anna; Ramette, Alban; Pantoja, Silvio; Rossel, Pamela E; Schubert, Carsten J; Struck, Ulrich; Boetius, Antje

    2017-02-01

    Bottom-water oxygen supply is a key factor governing the biogeochemistry and community composition of marine sediments. Whether it also determines carbon burial rates remains controversial. We investigated the effect of varying oxygen concentrations (170 to 0 μM O2) on microbial remineralization of organic matter in seafloor sediments and on community diversity of the northwestern Crimean shelf break. This study shows that 50% more organic matter is preserved in surface sediments exposed to hypoxia compared to oxic bottom waters. Hypoxic conditions inhibit bioturbation and decreased remineralization rates even within short periods of a few days. These conditions led to the accumulation of threefold more phytodetritus pigments within 40 years compared to the oxic zone. Bacterial community structure also differed between oxic, hypoxic, and anoxic zones. Functional groups relevant in the degradation of particulate organic matter, such as Flavobacteriia, Gammaproteobacteria, and Deltaproteobacteria, changed with decreasing oxygenation, and the microbial community of the hypoxic zone took longer to degrade similar amounts of deposited reactive matter. We conclude that hypoxic bottom-water conditions-even on short time scales-substantially increase the preservation potential of organic matter because of the negative effects on benthic fauna and particle mixing and by favoring anaerobic processes, including sulfurization of matter.

  11. Initial cloning and sequencing of hydHG, an operon homologous to ntrBC and regulating the labile hydrogenase activity in Escherichia coli K-12.

    PubMed Central

    Stoker, K; Reijnders, W N; Oltmann, L F; Stouthamer, A H

    1989-01-01

    To isolate genes from Escherichia coli which regulate the labile hydrogenase activity, a plasmid library was used to transform hydL mutants lacking the labile hydrogenase. A single type of gene, designated hydG, was isolated. This gene also partially restored the hydrogenase activity in hydF mutants (which are defective in all hydrogenase isoenzymes), although the low hydrogenase 1 and 2 levels were not induced. Therefore, hydG apparently regulates, specifically, the labile hydrogenase activity. Restoration of this latter activity in hydF mutants was accompanied by a proportional increase of the H2 uptake activity, suggesting a functional relationship. H2:fumarate oxidoreductase activity was not restored in complemented hydL mutants. These latter strains may therefore lack, in addition to the labile hydrogenase, a second component (provisionally designated component R), possibly an electron carrier coupling H2 oxidation to the anerobic respiratory chain. Sequence analysis showed an open reading frame of 1,314 base pairs for hydG. It was preceded by a ribosome-binding site but apparently lacked a promoter. Minicell experiments revealed a single polypeptide of approximately 50 kilodaltons. Comparison of the predicted amino acid sequence with a protein sequence data base revealed strong homology to NtrC from Klebsiella pneumoniae, a DNA-binding transcriptional activator. The 411 base pairs upstream from pHG40 contained a second open reading frame overlapping hydG by four bases. The deduced amino acid sequence showed considerable homology with the C-terminal part of NtrB. This sequence was therefore assumed to be part of a second gene, encoding the NtrB-like component, and was designated hydH. The labile hydrogenase activity in E. coli is apparently regulated by a multicomponent system analogous to the NtrB-NtrC system. This conclusion is in agreement with the results of Birkmann et al. (A. Birkmann, R. G. Sawers, and A. Böck, Mol. Gen. Genet. 210:535-542, 1987), who

  12. Characterization of a labile naloxone binding site (lambda site) in rat brain.

    PubMed

    Grevel, J; Yu, V; Sadée, W

    1985-05-01

    A high-affinity binding site selective for naloxone and other 4,5-epoxymorphinans (lambda site) has been previously described in rat brain. Following homogenization of freshly dissected brain, the lambda sites convert from a high-affinity to a low-affinity state. When measured with [3H]naloxone, the decay is very rapid at 20 degrees C (t 1/2 less than 2 min), whereas it is progressively slowed at lower temperatures. Proteinase inhibitors, antoxidants, and sulfhydryl group-protecting agents failed to prevent this conversion. Kinetic measurements of mu and lambda binding at varying temperatures demonstrated that the decrease in lambda binding does not coincide with the concurrent increase in mu binding and that the loss of high-affinity lambda binding at 20 degrees C can be partially restored when the temperature is lowered to 0 degrees C. The low-affinity state of the lambda site is rather stable in the Tris buffer homogenates and is susceptible to digestion by a protease. The (-)-isomer of WIN 44,441, a benzomorphan drug, binds to lambda sites with moderate affinity (dissociation constant, KD = 63 nM), whereas the (+)-isomer does not (KD greater than 10,000 nM), thus establishing stereoselectivity of the binding process. Neither the high-affinity nor the low-affinity state of lambda binding is significantly affected by the presence of 100 mM sodium chloride or 50 microM Gpp(NH)p, (a GTP analog), which is in contrast to the dramatic effect of these agents on the established opioid receptor system. Naltrexone, naloxone, nalorphine, and morphine (in this order of decreasing potency) bind to the lambda site in vivo in intact rat brain over dosage ranges that are commonly employed in pharmacological studies.

  13. Localisation and quantification of alkali-labile sites in human spermatozoa by DNA breakage detection-fluorescence in situ hybridisation.

    PubMed

    Cortés-Gutiérrez, E I; Dávila-Rodríguez, M I; Cerda-Flores, R M; Fernández, J L; López-Fernández, C; Aragón Tovar, A R; Gosálvez, J

    2015-03-01

    The localisation and quantification of constitutive alkali-labile sites (ALSs) were investigated using a protocol of DNA breakage detection plus fluorescence in situ hybridisation (DBD-FISH) and alkaline single-cell gel electrophoresis (SCGE or comet assay), in spermatozoa of infertile and fertile men. Semen samples from 10 normozoospermic patients undergoing infertility treatment and 10 fertile men were included in this study. ALSs were localised and quantified by DBD-FISH. The region most sensitive to alkali treatment in human spermatozoa was located in the basal region of the head. ALSs were more frequent in spermatozoa of infertile men than in those of fertile men. These results were confirmed by SCGE comet assays. In conclusion, the most intense localisation of hybridisation signals in human spermatozoa, representing the highest density of constitutive ALSs, was not randomly distributed and was predominantly located in the base of the head. Moreover, infertile men presented with an increase in ALS frequency. Further studies are necessary to determine the association between ALS, sperm chromatin organisation and infertility.

  14. PEG-detachable and acid-labile cross-linked micelles based on orthoester linked graft copolymer for paclitaxel release

    NASA Astrophysics Data System (ADS)

    Yuan, Zhefan; Huang, Jingyi; Liu, Jing; Cheng, Sixue; Zhuo, Renxi; Li, Feng

    2011-08-01

    Polyethylene glycol detachable graft copolymer, mPEG-g-p(NAS-co-BMA), was synthesized by grafting 2-(ω-methoxy)PEGyl-1,3-dioxan-5-ylamine onto poly(N-(acryloyloxy)succinimide-co-butyl methacrylate). Pseudo in situ cross-linking of the mPEG-g-p(NAS-co-BMA) was performed in dimethylformamide phosphate buffer (v/v = 1/1) by an acid-labile diamine cross-linker bearing two symmetrical cyclic orthoesters. The cross-linked (CL) micelles with different contents of mPEG segments represented different morphologies. The CL micelles containing approximately one mPEG segment exhibited 'echini' morphology whereas the CL micelle with approximately three mPEG segments formed nanowires. The hydrolysis rate of the CL micelles is highly pH-dependent and much more rapid at mild acid than physiological conditions. Hydrolyzates of the CL micelles formed vesicles because new amphiphilic copolymers were formed. Paclitaxel (PTX) was successfully loaded into the CL micelles and a controlled and pH-dependent release behavior was observed. No obvious cytotoxicity was found for the CL micelles at concentration as high as 800 mg l - 1.

  15. Comparison of two GM1-erythrocyte assays to detect heat-labile Escherichia coli enterotoxin in stool specimens.

    PubMed Central

    Germani, Y; Guesdon, J L; Phalente, L; Begaud, E; Moreau, J P

    1988-01-01

    Two erythrocyte immunoassay techniques to detect the presence of Escherichia coli heat-labile enterotoxin (LTh) in stool supernatants and cell-free culture supernatants were compared. In the competitive assay, GM1 ganglioside was coated onto V-shaped-well microdilution plates and enterotoxin was coupled to sheep erythrocytes. As little as 0.8 ng of LTh per ml was detected by this method, which was based on the competition between the LTh of the test sample and the sensitized erythrocytes. The second assay made use of chimera antibody prepared by coupling polyclonal anti-LTh antibody to a monoclonal antibody specific for sheep erythrocytes. In this case, LTh, which was specifically bound to a GM1 ganglioside-coated plate, was detected by successively adding the chimera antibody and sheep erythrocytes. The limit of detection of the chimera antibody erythrocyte immunoassay was 0.2 ng/ml. Stool samples were collected from 167 infants hospitalized for diarrhea in the hospital of Noumea, New Caledonia. False-negative reactions due to proteases present in the stool samples were avoided by the addition of phenylmethylsulfonyl fluoride. Images PMID:3290242

  16. A kinetic study of stimulus-induced vesicle recycling in electromotor nerve terminals using labile and stable vesicle markers.

    PubMed

    Agoston, D V; Dowe, G H; Fiedler, W; Giompres, P E; Roed, I S; Walker, J H; Whittaker, V P; Yamaguchi, T

    1986-11-01

    The kinetics of recovery, by recycling electromotor synaptic vesicles, of the biophysical parameters of the reserve population has been studied in perfused blocks of electric organ of Torpedo marmorata prestimulated in vivo, followed by density gradient separation of the extracted vesicles in a zonal rotor using labile (acetylcholine and ATP) and stable (proteoglycan) vesicle markers. Stimulation in vivo at 0.15 Hz for 3.3 h depleted tissue acetylcholine much less than stimulation at 1 Hz for 1 h but nevertheless generated a much larger pool of recycled vesicles that recovered more slowly. At the lower rate of stimulation, recovery of the biophysical characteristics of the reserve population by the recycled vesicles, identified by their content of newly synthesized transmitter, was essentially complete by 8 h. The stable proteoglycan marker was immunochemically assayed and was bimodally distributed in the vesicle-containing portion of the density gradient even in experiments with unstimulated or recovered tissue. The second peak corresponded with that of newly synthesized transmitter and was thus identified as containing the recycled vesicles. Its normalized acetylcholine/proteoglycan ratio was lower than that of the first peak, which is consistent with earlier findings that recycled vesicles, before recovery, are only partially loaded with transmitter. However, as expected, the proportion of total vesicular proteoglycan and acetylcholine associated with the recycled vesicle fraction was very much lower in preparations derived from unstimulated or recovered tissue than in those from recently stimulated tissue.

  17. Synthesis and self-assembly of spin-labile and redox-active manganese(III) complexes.

    PubMed

    Gandolfi, Claudio; Cotting, Tatiana; Martinho, Paulo N; Sereda, Olha; Neels, Antonia; Morgan, Grace G; Albrecht, Martin

    2011-03-07

    New amphiphilic and spin-labile Mn(III) complexes based on dianionic N(4)O(2)-hexadentate sal(2)trien or sal(2)bapen ligands, which contain OC(6)H(13), OC(12)H(25), or OC(18)H(37) alkoxy substituents at different positions of the salicylidene unit were prepared (H(2)sal(2)trien = N,N'''-bis(salicylidene)-1,4,7,10-tetraazadecane, H(2)sal(2)bapen = N,N'''-bis(salicylidene)-1,5,8,12-tetraazadodecane). According to electrochemical measurements, these complexes undergo two (quasi)reversible redox processes. Temperature-dependent magnetic measurements revealed a high-spin configuration for all sal(2)trien complexes (S = 2) and gradual spin crossover for sal(2)bapen complexes from high to low spin (S = 1). The chain length strongly influences the spin crossover, as C(18)-functionalization stabilizes the low spin state at much higher temperatures than shorter alkyl chains. Moreover, long alkyl chains allow for spontaneous self-assembly of the molecules, which was investigated in single crystals and in Langmuir-films at the air-water interface. Long alkyl chains (C(12) or C(18)) as well as a mutual syn-orientation of these molecular recognition sites were required for the Langmuir monolayers to be stable.

  18. Contact-facilitated drug delivery with Sn2 lipase labile prodrugs optimize targeted lipid nanoparticle drug delivery

    PubMed Central

    Pan, Dipanjan; Pham, Christine TN; Weilbaecher, Katherine N; Tomasson, Michael H; Wickline, Samuel A; Lanza, Gregory M

    2016-01-01

    Sn2 lipase labile phospholipid prodrugs in conjunction with contact-facilitated drug delivery offer an important advancement in Nanomedicine. Many drugs incorporated into nanosystems, targeted or not, are substantially lost during circulation to the target. However, favorably altering the pharmacokinetics and volume of distribution of systemic drug delivery can offer greater efficacy with lower toxicity, leading to new prolonged-release nanoexcipients. However, the concept of achieving Paul Erhlich's inspired vision of a ‘magic bullet’ to treat disease has been largely unrealized due to unstable nanomedicines, nanosystems achieving low drug delivery to target cells, poor intracellular bioavailability of endocytosed nanoparticle payloads, and the substantial biological barriers of extravascular particle penetration into pathological sites. As shown here, Sn2 phospholipid prodrugs in conjunction with contact-facilitated drug delivery prevent premature drug diffusional loss during circulation and increase target cell bioavailability. The Sn2 phospholipid prodrug approach applies equally well for vascular constrained lipid-encapsulated particles and micelles the size of proteins that penetrate through naturally fenestrated endothelium in the bone marrow or thin-walled venules of an inflamed microcirculation. At one time Nanomedicine was considered a ‘Grail Quest’ by its loyal opposition and even many in the field adsorbing the pains of a long-learning curve about human biology and particles. However, Nanomedicine with innovations like Sn2 phospholipid prodrugs has finally made ‘made the turn’ toward meaningful translational success. PMID:26296541

  19. Immunochromatographic detection of the heat-labile enterotoxin of enterotoxigenic Escherichia coli with cross-detection of cholera toxin.

    PubMed

    Arimitsu, Hideyuki; Sasaki, Keiko; Tsuji, Takao

    2017-01-01

    Here, we report the development of an immunochromatographic test strip that can detect heat-labile enterotoxin (LT) produced by enterotoxigenic Escherichia coli. Five types of monoclonal antibody (mAb)-producing hybridomas were isolated: three mAbs were A subunit specific and two were B subunit specific. Four mAbs also cross-reacted with both LT proteins derived from swine and human E. coli strains, but only one mAb 57B9 additionally cross-reacted with cholera toxin. Thus, mAb 57B9 was used to form a gold colloid-conjugated antibody for the immunochromatographic test by combination with polyclonal anti-LT rabbit IgG. This test strip detected not only LT in the culture supernatant of LT gene-positive strains, but also cholera toxin in the culture supernatant of Vibrio cholerae. These results indicate that this test strip is suitable for the diagnosis of both enterotoxigenic E. coli and V. cholerae infection.

  20. Effects of grazing intensity on soil labile organic carbon fractions in a desert steppe area in Inner Mongolia.

    PubMed

    Cao, Jixin; Wang, Xiaoping; Sun, Xiangyang; Zhang, Lin; Tian, Yun

    2013-01-01

    Grazing can cause changes in soil carbon (C) level. This study aimed to elucidate the response of soil labile organic carbon (SLOC) under four different grazing intensities: non grazing (NG), 0 sheep·ha(-1); light grazing (LG), 0.91 sheep·ha(-1); moderate grazing (MG), 1.82 sheep·ha(-1), and heavy grazing (HG), 2.73 sheep·ha(-1). Results showed that there was no significant difference in total soil organic carbon (TOC) and soil inorganic carbon (SIC) content from three soil depths (0-15 cm, 15-30 cm, and 30-45 cm) under different grazing intensities. However, the SLOC including particulate organic carbon (POC), light fraction organic carbon (LFOC), and readily oxidizable carbon (ROC) content at a depth of 0-15 cm decreased with the increasing grazing intensity among LG, MG and HG. The SLOC content at depths of 15-30 cm under the NG and LG were significantly higher than that under the MG and the HG. The TOC and SLOC content decreased with increasing depths of soil horizons, but SIC content increased. The variation trend of the density of different soil carbon fractions and the ratio of individual SLOC fractions to TOC were similar to that of the soil carbon content of corresponding fractions. These results indicated that MG and HG treatments caused C loss at 0-30 cm; and SLOC was more sensitive than TOC in response to different grazing intensities.

  1. Anatomical Network Analysis Shows Decoupling of Modular Lability and Complexity in the Evolution of the Primate Skull

    PubMed Central

    Esteve-Altava, Borja; Boughner, Julia C.; Diogo, Rui; Villmoare, Brian A.; Rasskin-Gutman, Diego

    2015-01-01

    Modularity and complexity go hand in hand in the evolution of the skull of primates. Because analyses of these two parameters often use different approaches, we do not know yet how modularity evolves within, or as a consequence of, an also-evolving complex organization. Here we use a novel network theory-based approach (Anatomical Network Analysis) to assess how the organization of skull bones constrains the co-evolution of modularity and complexity among primates. We used the pattern of bone contacts modeled as networks to identify connectivity modules and quantify morphological complexity. We analyzed whether modularity and complexity evolved coordinately in the skull of primates. Specifically, we tested Herbert Simon’s general theory of near-decomposability, which states that modularity promotes the evolution of complexity. We found that the skulls of extant primates divide into one conserved cranial module and up to three labile facial modules, whose composition varies among primates. Despite changes in modularity, statistical analyses reject a positive feedback between modularity and complexity. Our results suggest a decoupling of complexity and modularity that translates to varying levels of constraint on the morphological evolvability of the primate skull. This study has methodological and conceptual implications for grasping the constraints that underlie the developmental and functional integration of the skull of humans and other primates. PMID:25992690

  2. Anatomical network analysis shows decoupling of modular lability and complexity in the evolution of the primate skull.

    PubMed

    Esteve-Altava, Borja; Boughner, Julia C; Diogo, Rui; Villmoare, Brian A; Rasskin-Gutman, Diego

    2015-01-01

    Modularity and complexity go hand in hand in the evolution of the skull of primates. Because analyses of these two parameters often use different approaches, we do not know yet how modularity evolves within, or as a consequence of, an also-evolving complex organization. Here we use a novel network theory-based approach (Anatomical Network Analysis) to assess how the organization of skull bones constrains the co-evolution of modularity and complexity among primates. We used the pattern of bone contacts modeled as networks to identify connectivity modules and quantify morphological complexity. We analyzed whether modularity and complexity evolved coordinately in the skull of primates. Specifically, we tested Herbert Simon's general theory of near-decomposability, which states that modularity promotes the evolution of complexity. We found that the skulls of extant primates divide into one conserved cranial module and up to three labile facial modules, whose composition varies among primates. Despite changes in modularity, statistical analyses reject a positive feedback between modularity and complexity. Our results suggest a decoupling of complexity and modularity that translates to varying levels of constraint on the morphological evolvability of the primate skull. This study has methodological and conceptual implications for grasping the constraints that underlie the developmental and functional integration of the skull of humans and other primates.

  3. Low Molecular Weight PEI-Based Vectors via Acid-Labile Ortho Ester Linkage for Improved Gene Delivery.

    PubMed

    Zhang, Lei; Yu, Min; Wang, Jun; Tang, Rupei; Yan, Guoqing; Yao, Weijing; Wang, Xin

    2016-08-01

    A series of novel pH-sensitive gene delivery vectors (POEI 1, 2, and 3) are synthesized through Michael addition from low molecular weight PEI (LMW PEI) via acid-labile ortho ester linkage with terminal acrylates (OEAc) by various feed molar ratios. The obtained POEI 1 and POEI 2 can efficiently condense plasmid DNA into nanoparticles with size range of 200-300 nm and zeta-potentials of about +15 mV while protecting DNA from enzymatic digestion compared with POEI 3. Significantly, ortho ester groups of POEI main-chains can make an instantaneous degradation-response to acidic endosomal pH (≈5.0), resulting in accelerated disruption of polyplexes and intracellular DNA release. MTT assay reveals that all POEIs exhibit much lower cytotoxicity in different cells than branched PEI (25 KDa). As expected, POEI 1 and POEI 2 perform improved gene transfection in vitro, suggesting that such polycations might be promising gene vectors based on overcoming toxicity-efficiency contradiction.

  4. Chemical Composition, Antibacterial, Antibiofilm and Synergistic Properties of Essential Oils from Eucalyptus globulus Labill. and Seven Mediterranean Aromatic Plants.

    PubMed

    Vieira, Maria; Bessa, Lucinda J; Martins, M Rosário; Arantes, Sílvia; Teixeira, António P S; Mendes, Ângelo; Martins da Costa, Paulo; Belo, Anabela D F

    2017-03-09

    Essential oils (EOs) from Eucalyptus globulus Labill. ssp. globulus and from Mediterranean autochthonous aromatic plants - Thymus mastichina L., Mentha pulegium L., Rosmarinus officinalis L., Calamintha nepeta (L.) Savi ssp. nepeta, Cistus ladanifer L., Foeniculum vulgare L., Dittrichia viscosa (L.) Greuter ssp. viscosa - were extracted by hydrodistillation and characterized by GC-FID and NMR spectroscopy. EOs were evaluated for antimicrobial properties against several bacterial strains, using diverse methods, namely, the agar disc-diffusion method, the microdilution method, the crystal violet assay and the Live/Dead staining for assessment of biofilm formation. Potential synergy was assessed by a checkerboard method. EOs of R. officinalis and C. ladanifer showed a predominance in monoterpene hydrocarbons (>60%); EOs of C. nepeta, M. pulegium, T. mastichina, E. globulus and F. vulgare were rich in oxygenated monoterpenes (62-96%) whereas EO of D. viscosa was mainly composed of oxygenated sesquiterpenes (54%). All EOs showed antimicrobial activity; M. pulegium and E. globulus generally had the strongest antimicrobial activity. EO of C. nepeta was the most promising in hampering the biofilm formation. The combinations D. viscosa/C. nepeta and E. globulus/T. mastichina were synergistic against Staphylococcus aureus. These results support the notion that EOs from the aromatic plants herein reported should be further explored as potential pharmaceuticals and/or food preservatives. This article is protected by copyright. All rights reserved.

  5. Influence of the aqueous film coating process on the properties and stability of tablets containing a moisture-labile drug.

    PubMed

    Ruotsalainen, Mirja; Heinämäki, Jyrki; Taipale, Krista; Yliruusi, Jouko

    2003-01-01

    The effects of an aqueous film coating process on the morphology and storage stability of hydroxypropyl methylcellulose-coated tablets containing a moisture-labile model drug (acetylsalicylic acid, ASA) were evaluated using an instrumented side-vented tablet pan coater. Coating parameters studied were inlet air absolute humidity 5 g/m3 and 12 g/m3, spraying air pressure 100 kPa and 500 kPa, pan air temperature 35 degrees C and 55 degrees C, and coating solution flow rate 2.2 g/min and 7.8 g/min. The surface roughness of the coatings was measured with a laser profilometer and the chemical hydrolysis of the model drug ASA with an UV-spectrophotometer. The film-coated tablets were stored at 25 degrees C/60% RH and 40 degrees C/75% RH for three months. The high absolute humidity of the inlet air increased the residual water content and surface roughness of the coated tablets. Using a lower coating solution flow rate, higher spraying air pressure and pan temperature the coatings were smooth and homogeneous. In both ambient and accelerated storage conditions, the roughness of the coatings and the hydrolysis of ASA increased, but this was independent of the film coating process. Uniform and smooth hydroxypropyl methylcellulose coatings can be achieved by improved control of process parameters related to the application of the coating solution and water evaporation of the tablet surface.

  6. Metal Fluxes from Porewaters and Labile Sediment Phases for Predicting Metal Exposure and Bioaccumulation in Benthic Invertebrates.

    PubMed

    Amato, Elvio D; Simpson, Stuart L; Belzunce-Segarra, Maria J; Jarolimek, Chad V; Jolley, Dianne F

    2015-12-15

    The use of diffusive gradients in thin films (DGT) for predicting metal bioavailability was investigated by exposing the bivalve Tellina deltoidalis to an identical series of metal-contaminated sediments deployed simultaneously in the field and laboratory. To understand the differences in metal exposure occurring between laboratory- and field-based bioassays, we investigated changes in metal fluxes to DGT probes in sediments and in metal concentrations and partitioning to porewaters and overlying waters. DGT-metal fluxes (Cu, Pb, and Zn) were lower in the overlying waters of most field bioassays compared to the laboratory, causing differences in Pb and Zn bioaccumulation between bivalves exposed to laboratory and field conditions. Overall, DGT-metal fluxes provided predictions of metal bioaccumulation similar to those obtained using dilute-acid extractable metal measurements. This study demonstrates that, irrespective of the physicochemical properties of the sediment and type of exposure (laboratory or field), sediments pose a significant risk of bioaccumulation by T. deltoidalis when the Cu, Pb, and Zn DGT flux exceeds 3.5, 1.3, and 156 μg/h/m(2), respectively. The results presented here support the use of the DGT technique for sediment quality assessment and the hypothesis that DGT-metal fluxes may potentially be useful surrogates for the lability of metals for all exposure routes.

  7. The suppressive activities of six sources of medicinal ferns known as gusuibu on heat-labile enterotoxin-induced diarrhea.

    PubMed

    Chang, Hung-Chi; Chen, Jaw-Chyun; Yang, Jiun-Long; Tsay, Hsin-Sheng; Hsiang, Chien-Yun; Ho, Tin-Yun

    2014-02-18

    Diarrheal disease is one of the most important worldwide health problems. Enterotoxigenic Escherichia coli (ETEC) is the most frequently isolated enteropathogen in diarrheal diseases. In developing countries, a very large number of people, especially children, suffer from diarrhea. To combat this problem, World Health Organization has constituted the Diarrhea Diseases Control Program which guides studies on traditional medicinal practices and preventive measures. Gusuibu, a traditional folk medicine, has been claimed to heal certain types of diarrhea. However, so far no scientific study has been carried out on the anti-diarrheal mechanism of Gusiubu. The present study was performed to examine the suppressive activities of ethanol extracts of six sources of folk medicinal ferns used as Gusuibu on heat-labile enterotoxin (LT)-induced diarrhea. Inhibitory effects of six sources were evaluated on the ETEC LT subunit B (LTB) and monosialotetrahexosylganglioside (GMI) interaction by GM1-enzyme linked immunosorbent assay and patent mouse gut assay. Our results indicated that Drynaria fortunei had no anti-diarrheal effect, while, among the remaining five folk medicinal ferns, four belonging to family Davalliaceae had significant abilities on both the blocking of LTB and GM1 interaction and the inhibition of LT-induced diarrhea. In conclusion, these findings suggested the potential application of Gusuibu as an anti-diarrheal remedy.

  8. Interaction with Cfd1 increases the kinetic lability of FeS on the Nbp35 scaffold.

    PubMed

    Pallesen, Leif J; Solodovnikova, Natalia; Sharma, Anil K; Walden, William E

    2013-08-09

    P-loop NTPases of the ApbC/Nbp35 family are involved in FeS protein maturation in nearly all organisms and are proposed to function as scaffolds for initial FeS cluster assembly. In yeast and animals, Cfd1 and Nbp35 are homologous P-loop NTPases that form a heterotetrameric complex essential for FeS protein maturation through the cytosolic FeS cluster assembly (CIA) pathway. Cfd1 is conserved in animals, fungi, and several archaeal species, but in many organisms, only Nbp35 is present, raising the question of the unique roles played by Cfd1 and Nbp35. To begin to investigate this issue, we examined Cfd1 and Nbp35 function in budding yeast. About half of each protein was detected in a heterocomplex in logarithmically growing yeast. Nbp35 readily bound (55)Fe when fed to cells, whereas (55)Fe binding by free Cfd1 could not be detected. Rapid (55)Fe binding to and release from Nbp35 was impaired by Cfd1 deficiency. A Cfd1 mutation that caused a defect in heterocomplex stability supported iron binding to Nbp35 but impaired iron release. Our results suggest a model in which Cfd1-Nbp35 interaction increases the lability of assembled FeS on the Nbp35 scaffold for transfer to target apo-FeS proteins.

  9. Effect of inorganic and organic copper fertilizers on copper nutrition in Spinacia oleracea and on labile copper in soil.

    PubMed

    Obrador, Ana; Gonzalez, Demetrio; Alvarez, Jose M

    2013-05-22

    To ensure an optimal concentration of Cu in food crops, the effectiveness of eight liquid Cu fertilizers was studied in a spinach ( Spinacia oleracea L.) crop grown on Cu-deficient soil under greenhouse conditions. Plant dry matter yields, Cu concentrations in spinach plants (total and morpholino acid (MES)- and ethylenediaminedisuccinic acid (EDDS)-extractable), and Cu uptakes were studied. The behavior of Cu in soil was evaluated by both single and sequential extraction procedures. The highest quantities of Cu in labile forms in the soil, total uptakes, and Cu concentrations in the plants were associated with the application of the two sources that contained Cu chelated by EDTA and/or DTPA. The fertilizers containing these Cu chelates represent a promising approach to achieve high levels of agronomic biofortification. The stronger correlations obtained between low-molecular-weight organic acid-extractable Cu in soil and the Cu concentrations and Cu uptakes by the plants show the suitability of this soil extraction method for predicting Cu available to spinach plants.

  10. Comparative Adjuvant Effects of Type II Heat-Labile Enterotoxins in Combination with Two Different Candidate Ricin Toxin Vaccine Antigens.

    PubMed

    Vance, David J; Greene, Christopher J; Rong, Yinghui; Mandell, Lorrie M; Connell, Terry D; Mantis, Nicholas J

    2015-12-01

    Type II heat-labile enterotoxins (HLTs) constitute a promising set of adjuvants that have been shown to enhance humoral and cellular immune responses when coadministered with an array of different proteins, including several pathogen-associated antigens. However, the adjuvant activities of the four best-studied HLTs, LT-IIa, LT-IIb, LT-IIb(T13I), and LT-IIc, have never been compared side by side. We therefore conducted immunization studies in which LT-IIa, LT-IIb, LT-IIb(T13I), and LT-IIc were coadministered by the intradermal route to mice with two clinically relevant protein subunit vaccine antigens derived from the enzymatic A subunit (RTA) of ricin toxin, RiVax and RVEc. The HLTs were tested with low and high doses of antigen and were assessed for their abilities to stimulate antigen-specific serum IgG titers, ricin toxin-neutralizing activity (TNA), and protective immunity. We found that all four HLTs tested were effective adjuvants when coadministered with RiVax or RVEc. LT-IIa was of particular interest because as little as 0.03 μg when coadministered with RiVax or RVEc proved effective at augmenting ricin toxin-specific serum antibody titers with nominal evidence of local inflammation. Collectively, these results justify the need for further studies into the mechanism(s) underlying LT-IIa adjuvant activity, with the long-term goal of evaluating LT-IIa's activity in humans.

  11. Blue carbon for how long? Lability of buried salt marsh carbon released via erosion.

    NASA Astrophysics Data System (ADS)

    Cox, D.; Currin, C.; Mctigue, N.

    2015-12-01

    With our climate rapidly changing due to increasing greenhouse gas emissions, the ability of coastal wetlands to sequester carbon (C) on century to millennial time scales has bolstered new interest in these habitats. This stored sedimentary organic carbon termed "blue C" can be eroded to surface horizons from the impacts of sea level rise, storm events, or other physical modifications of the coastline, potentially returning CO2 to the atmosphere upon microbially mediated remineralization. The rates and extent of these remineralization processes are largely unknown. A field exercise revealed a horizontal gradient in the organic matter content of marsh sediments perpendicular to creek banks, as proximity to tidal creeks resulted in a decline in sediment C content, with some variation due to creekbank morphology. We also conducted lab experiments to test the effect of temperature, as in some systems it has been found that a 1°C increase in temperature increases organic matter decomposition rates by 20%. In this study, fluxes of dissolved inorganic carbon (DIC), pH, and pCO2 were measured to determine carbon remineralization rates of marsh sediment collected 30 cm below the surface. A 20°C and 30°C temperature treatment was instituted to examine Q10 and activation energy of the decomposition processes that could potentially act as a climate change positive feedback upon erosion of blue carbon. Laboratory results show that the century-old blue carbon overall is refractory to tidal creek microbes, as only a maximum of 0.28% of sediment organic C was respired in two-week incubations. However, the remineralization rate exhibited a Q10 of 2.45, indicating that the organic carbon, despite being refractory, is temperature sensitive and will degrade exponentially if exposed to higher temperatures. These rates were then modeled at current and projected temperature profiles and applied to actual erosion rates in the study site to assess the release of carbon dioxide via

  12. Lysosomal pH-inducible supramolecular dissociation of polyrotaxanes possessing acid-labile N-triphenylmethyl end groups and their therapeutic potential for Niemann-Pick type C disease

    PubMed Central

    Tamura, Atsushi; Nishida, Kei; Yui, Nobuhiko

    2016-01-01

    Abstract Niemann-Pick type C (NPC) disease is characterized by the accumulation of cholesterol in lysosomes. We have previously reported that biocleavable polyrotaxanes (PRXs) composed of β-cyclodextrins (β-CDs) threaded onto a linear polymer capped with bulky stopper molecules via intracellularly cleavable linkers show remarkable cholesterol reducing effects in NPC disease patient-derived fibroblasts owing to the stimuli-responsive intracellular dissociation of PRXs and subsequent β-CD release from the PRXs. Herein, we describe a series of novel acid-labile 2-(2-hydroxyethoxy)ethyl group-modified PRXs (HEE-PRXs) bearing terminal N-triphenylmethyl (N-Trt) groups as a cleavable component for the treatment of NPC disease. The N-Trt end groups of the HEE-PRXs underwent acidic pH-induced cleavage and led to the dissociation of their supramolecular structure. A kinetic study revealed that the number of HEE groups on the PRX did not affect the cleavage kinetics of the N-Trt end groups of the HEE-PRXs. The effect of the number of HEE groups of the HEE-PRXs, which was modified to impart water solubility to the PRXs, on cellular internalization efficiency, lysosomal localization efficiency, and cholesterol reduction ability in NPC disease-derived fibroblasts (NPC1 fibroblasts) was also investigated. The cellular uptake and lysosomal localization efficiency were almost equivalent for HEE-PRXs with different numbers of HEE groups. However, the cholesterol reducing ability of the HEE-PRXs in NPC1 fibroblasts was affected by the number of HEE groups, and HEE-PRXs with a high number of HEE groups were unable to reduce lysosomal cholesterol accumulation. This deficiency is most likely due to the cholesterol-solubilizing ability of HEE-modified β-CDs released from the HEE-PRXs. We conclude that the N-Trt group acts as a cleavable component to induce the lysosomal dissociation of HEE-PRXs, and acid-labile HEE-PRXs with an optimal number of HEE groups (4.1 to 5.4 HEE groups per

  13. The labile respiratory activity of ribcage muscles of the rat during sleep.

    PubMed

    Megirian, D; Pollard, M J; Sherrey, J H

    1987-08-01

    1. Sleep-waking states of chronically implanted rats were identified polygraphically while recording the integrated electromyogram (e.m.g.) of extrinsic (scalenus medius and levator costae) and intrinsic (external and internal interosseous intercostal and parasternal) muscles of the thoracic cage. Rats breathed air, air enriched in CO2 (5%) or air deficient in O2 (10% O2 in N2) and were free to adopt any desired posture. 2. In non-rapid eye movement (non-r.e.m.) sleep, the scalenus medius and intercostal muscles of the cephalic spaces were always inspiratory; intercostal muscles of the mid-thoracic spaces were commonly expiratory while the more caudal ones were only occasionally expiratory. Expiratory activity, when present in quiet wakefulness, extended for a variable period of time into non-r.e.m. sleep and always disappeared in r.e.m. sleep regardless of the ribcage muscle under study. 3. Inspiratory activity, when present in non-r.e.m. sleep, was unaffected, partially attenuated or abolished at entry into r.e.m. sleep. The peak integrated e.m.g. activity of ribcage muscles was measured as a function of posture, gas mixture breathed and ribcage site: (a) the greater the degree of curled-up posture, the greater the respiratory activity of scalenus medius, an effect augmented by CO2 but depressed by hypoxia, and (b) the more caudally placed ribcage muscles exhibited respiratory activity which was essentially unaffected by posture and gas mixture inspired. 4. The presence or absence of tonic activity in ribcage respiratory muscles during non-r.e.m. sleep was unrelated to posture. When tonic activity was present, it always disappeared in r.e.m. sleep. When expiratory activity was present in non-r.e.m. sleep, it too always disappeared in r.e.m. sleep. Inspiratory activity present in non-r.e.m. sleep was variably affected at entry into r.e.m. sleep; it was unchanged, partially attenuated or abolished. 5. It is concluded that thoracic cage muscles exhibit marked

  14. Complexation efficiency of differently fixed 8-hydroxyquinoline and salicylic acid ligand groups for labile aluminium species determination in soils--comparison of two methods.

    PubMed

    Matús, Peter; Kubová, Jana

    2006-07-28

    Two methods utilizing the complexation of labile Al species by 8-hydroxyquinoline (HQN) and salicylic acid (SA) ligand groups were developed for aluminium operationally defined fractionation in acid soils. First, the solid phase extraction (SPE) procedure by a short-term ion-exchange batch reaction with chelating resins Iontosorb Oxin and Iontosorb Salicyl containing both ligand groups was used previously. Second, the 8-hydroxyquinoline, salicylic acid and ammonium salicylate agents with different concentrations by a single extraction protocol were applied in this paper. The flame atomic absorption spectrometry (FAAS) and optical emission spectrometry with inductively coupled plasma were used for aluminium quantification. The comparison of results from both methods show the possibility to supersede the first laborious method for the second simpler one in Al environmental risk assessment. The use of 1% 8-hydroxyquinoline in 2% acetic acid and 0.2% salicylic acid by a single extraction protocol without a need of sample filtration can supersede the SPE procedure in the Al pollution soil monitoring. Finally, the new scheme usable in a laboratory and moreover, directly in a field was proposed for Al fractionation in solid and liquid environmental samples. The labile Al species in soils and sediments are separated after their single leaching by 8-hydroxyquinoline or salicylic acid without a need of sample filtration. The labile Al species in soil solutions and natural waters are separated after their ultrafiltration followed by the SPE procedure with Iontosorb Oxin or Iontosorb Salicyl.

  15. Anaerobic BTEX degradation in oil sands tailings ponds: Impact of labile organic carbon and sulfate-reducing bacteria.

    PubMed

    Stasik, Sebastian; Wick, Lukas Y; Wendt-Potthoff, Katrin

    2015-11-01

    The extraction of bitumen from oil sands in Alberta (Canada) produces volumes of tailings that are pumped into large anaerobic settling-basins. Beside bitumen, tailings comprise fractions of benzene, toluene, ethylbenzene and xylenes (BTEX) that derive from the application of industrial solvents. Due to their toxicity and volatility, BTEX pose a strong concern for gas- and water-phase environments in the vicinity of the ponds. The examination of two pond profiles showed that concentrations of indigenous BTEX decreased with depth, pointing at BTEX transformation in situ. With depth, the relative contribution of ethylbenzene and xylenes to total BTEX significantly decreased, while benzene increased relatively from 44% to 69%, indicating preferential hydrocarbon degradation. To predict BTEX turnover and residence time, we determined BTEX degradation rates in tailings of different depths in a 180-days microcosm study. In addition, we evaluated the impact of labile organic substrates (e.g. acetate) generally considered to stimulate hydrocarbon degradation and the contribution of sulfate-reducing bacteria (SRB) to BTEX turnover. In all depths, BTEX concentrations significantly decreased due to microbial activity, with degradation rates ranging between 4 and 9 μg kg(-1) d(-1). BTEX biodegradation decreased linearly in correlation with initial concentrations, suggesting a concentration-dependent BTEX transformation. SRB were not significantly involved in BTEX consumption, indicating the importance of methanogenic degradation. BTEX removal decreased to 70-90% in presence of organic substrates presumptively due to an accumulation of acetate that lowered BTEX turnover due to product inhibition. In those assays SRB slightly stimulated BTEX transformation by reducing inhibitory acetate levels.

  16. Expression of a bioactive fusion protein of Escherichia coli heat-labile toxin B subunit to a synapsin peptide.

    PubMed

    Julia Scerbo, M; Bibolini, Mario J; Barra, José L; Roth, German A; Monferran, Clara G

    2008-06-01

    The B subunit of Escherichia coli heat-labile toxin (LTB) may function as an efficient carrier molecule for the delivery of genetically coupled antigens across the mucosal barrier. We constructed vectors for the expression of LTB and LTBSC proteins. LTBSC is a fusion protein that comprises the amino acid sequence from the C-domain of rat synapsin fused to the C-terminal end of LTB. Both constructions have a coding sequence for a 6His-tag fused in-frame. LTBSC was expressed in E. coli as inclusion bodies. The inclusion bodies were isolated and purified by Ni2+-chelating affinity chromatography under denaturing condition. Purified LTBSC was diluted in several refolding buffers to gain a soluble and biologically active protein. Refolded LTBSC assembled as an active oligomer which binds to the GM1 receptor in an enzyme-linked immunosorbent assay (ELISA). Soluble LTB in the E. coli lysate was also purified by Ni2+-chelating affinity chromatography and the assembled pentamer was able to bind with high affinity to GM1 in vitro. LTBSC and LTB were fed to rats and the ability to induce antigen-specific tolerance was tested. LTBSC inhibited the specific delayed-type hypersensitivity (DTH) response and induced decreased antigen-specific in vivo and in vitro cell proliferation more efficiently than LTB. Thus, the novel hybrid molecule LTBSC when orally delivered was able to elicit a systemic immune response. These results suggest that LTBSC could be suitable for exploring further therapeutic treatment of autoimmune inflammatory diseases involving antigens from central nervous system.

  17. Development of pH-sensitive self-nanoemulsifying drug delivery systems for acid-labile lipophilic drugs.

    PubMed

    Zhao, Tianjing; Maniglio, Devid; Chen, Jie; Chen, Bin; Migliaresi, Claudio

    2016-03-01

    Oral administration is the most convenient way of all the drug delivery routes. Orally administered bioactive compounds must resist the harsh acidic fluids or enzyme digestion in stomach, to reach their absorbed destination in small intestine. This is the case for silibinin, a drug used to protect liver cells against toxins that has also been demonstrated in vitro to possess anti-cancer effects. However, as many other drugs, silibinin can degrade in the stomach due to the action of the gastric fluid. The use of pH-sensitive self-nanoemulsifying drug delivery systems (pH-SNEDDS) could overcome the drawback due to degradation of the drug in the stomach while enhancing its solubility and dissolution rate. In this paper we have investigated pH-sensitive self-nanoemulsifying formulations containing silibinin as model drug. Pseudo-ternary phase diagrams have been constructed in order to identify the self-emulsification regions under different pH. Solubility of silibinin in selected formulations has been assessed and stability of the pure drug and of the silibinin loaded pH-SNEDDS formulations in simulated gastric fluid had been compared. Droplet size of the optimized pH-SNEDDS has been correlated to pH, volume of dilution medium and silibinin loading amount. TEM (transmission electron microscopy) studies have shown that emulsion droplets had spherical shape and narrow size distribution. In vitro drug release studies of the optimal pH-SNEDDS indicated substantial increase of the drug release and release rate in comparison to pure silibinin and to the commercial silibinin tablet. The results indicated that pH-SNEDDS have potential to improve the biopharmaceutics properties of acid-labile lipophilic drugs.

  18. Variable effects of labile carbon on the carbon use of different microbial groups in black slate degradation

    NASA Astrophysics Data System (ADS)

    Seifert, Anne-Gret; Trumbore, Susan; Xu, Xiaomei; Zhang, Dachung; Kothe, Erika; Gleixner, Gerd

    2011-05-01

    Weathering of ancient organic matter contributes significantly to biogeochemical carbon cycles over geological times. The principle role of microorganisms in this process is well recognized. However, information is lacking on the contribution of individual groups of microorganisms and on the effect of labile carbon sources to the degradation process. Therefore, we investigated the contribution of fungi, Gram-positive and Gram-negative bacteria in the degradation process using a column experiment. Investigations were performed on low metamorphic black slates. All columns contained freshly crushed, sieved (0.63-2 mm), not autoclaved black slates. Two columns were inoculated with the lignite-degrading fungus Schizophyllum commune and received a culture medium containing 13C labeled glucose, two columns received only this culture medium and two control columns received only water. The total mass balance was calculated from all carbon added to the slate and the CO 2 and DOC losses. Phospholipid fatty acids (PLFA) were extracted to investigate microbial communities. We used both the compound specific 14C and 13C signal of the PLFA to quantify carbon uptake from black slates and the glucose of the culture medium, respectively. The total carbon loss in these columns exceeded the amount of added carbon by approximately 60%, indicating that black slate carbon has been used. PLFA associated with Gram-positive bacteria dominated the indigenous community and took up 22% of carbon from black slate carbon, whereas PLFA of Gram-negative bacteria used only 8% of carbon from the slates. PLFA of Gram-negative bacteria and fungi were both mostly activated by the glucose addition. The added Schizophyllum did not establish well in the columns and was overgrown by the indigenous microbial community. Our results suggest that especially Gram-positive bacteria are able to live on and degrade black slate material. They also benefit from easy degradable carbon from the nutrient broth. In

  19. A simple and inexpensive enteric-coated capsule for delivery of acid-labile macromolecules to the small intestine.

    PubMed

    Miller, Darren S; Parsons, Anne Michelle; Bresland, John; Herde, Paul; Pham, Duc Minh; Tan, Angel; Hsu, Hung-yao; Prestidge, Clive A; Kuchel, Tim; Begg, Rezaul; Aziz, Syed Mahfuzul; Butler, Ross N

    2015-07-01

    Understanding the ecology of the gastrointestinal tract and the impact of the contents on the host mucosa is emerging as an important area for defining both wellness and susceptibility to disease. Targeted delivery of drugs to treat specific small intestinal disorders such as small bowel bacterial overgrowth and targeting molecules to interrogate or to deliver vaccines to the remote regions of the small intestine has proven difficult. There is an unmet need for methodologies to release probes/drugs to remote regions of the gastrointestinal tract in furthering our understanding of gut health and pathogenesis. In order to address this concern, we need to know how the regional delivery of a surrogate labeled test compound is handled and in turn, if delivered locally as a liquid or powder, the dynamics of its subsequent handling and metabolism. In the studies we report on in this paper, we chose (13)C sodium acetate ((13)C-acetate), which is a stable isotope probe that once absorbed in the small intestine can be readily measured non-invasively by collection and analysis of (13)CO2 in the breath. This would provide information of gastric emptying rates and an indication of the site of release and absorptive capacity. In a series of in vitro and in vivo pig experiments, we assessed the enteric-protective properties of a commercially available polymer EUDRAGIT(®) L100-55 on gelatin capsules and also on DRcaps(®). Test results demonstrated that DRcaps(®) coated with EUDRAGIT(®) L100-55 possessed enhanced enteric-protective properties, particularly in vivo. These studies add to the body of knowledge regarding gastric emptying in pigs and also begin the process of gathering specifications for the design of a simple and cost-effective enteric-coated capsule for delivery of acid-labile macromolecules to the small intestine.

  20. A simple and inexpensive enteric-coated capsule for delivery of acid-labile macromolecules to the small intestine*

    PubMed Central

    Miller, Darren S.; Parsons, Anne Michelle; Bresland, John; Herde, Paul; Pham, Duc Minh; Tan, Angel; Hsu, Hung-yao; Prestidge, Clive A.; Kuchel, Tim; Begg, Rezaul; Aziz, Syed Mahfuzul; Butler, Ross N.

    2015-01-01

    Understanding the ecology of the gastrointestinal tract and the impact of the contents on the host mucosa is emerging as an important area for defining both wellness and susceptibility to disease. Targeted delivery of drugs to treat specific small intestinal disorders such as small bowel bacterial overgrowth and targeting molecules to interrogate or to deliver vaccines to the remote regions of the small intestine has proven difficult. There is an unmet need for methodologies to release probes/drugs to remote regions of the gastrointestinal tract in furthering our understanding of gut health and pathogenesis. In order to address this concern, we need to know how the regional delivery of a surrogate labeled test compound is handled and in turn, if delivered locally as a liquid or powder, the dynamics of its subsequent handling and metabolism. In the studies we report on in this paper, we chose 13C sodium acetate (13C-acetate), which is a stable isotope probe that once absorbed in the small intestine can be readily measured non-invasively by collection and analysis of 13CO2 in the breath. This would provide information of gastric emptying rates and an indication of the site of release and absorptive capacity. In a series of in vitro and in vivo pig experiments, we assessed the enteric-protective properties of a commercially available polymer EUDRAGIT®L100-55 on gelatin capsules and also on DRcaps®. Test results demonstrated that DRcaps®coated with EUDRAGIT®L100-55 possessed enhanced enteric-protective properties, particularly in vivo. These studies add to the body of knowledge regarding gastric emptying in pigs and also begin the process of gathering specifications for the design of a simple and cost-effective enteric-coated capsule for delivery of acid-labile macromolecules to the small intestine. PMID:26160716

  1. Influence of Route of Administration on Immediate and Extended Protection in Rats Immunized with Escherichia coli Heat-Labile Enterotoxin

    PubMed Central

    Klipstein, Frederick A.; Engert, Richard F.

    1980-01-01

    The effect of route of administration, dosage, and number of boosts employed during immunization with the polymyxin-release form of Escherichia coli heat-labile (LT) enterotoxin on the degree and duration of protection afforded was evaluated in rats which were challenged by the ligated loop technique. Increasing the boosting dosage by fivefold from 50 to 250 μg resulted in a marked increase in protection against challenge with toxin in rats immunized either just by the parenteral route (i.p./i.p.) or by a parenteral prime, followed by peroral boosts (i.p./p.o.) in rats pretreated with cimetidine to ablate gastric secretions; such was not the case, however, even with a 50-fold increase in dosage in rats immunized just by the peroral route (p.o./p.o.). Four weekly peroral boosts were required to achieve the strongest degree of protection. Increasing the boosting dosage also increased the degree of protection against challenge with viable LT+/ST− and LT+/ST+ strains (ST indicates heat-stable enterotoxin) in rats immunized by the i.p./p.o., but not by the i.p./i.p., route; no protection was evident against an LT−/ST+ strain. Protection was lost within 3 weeks after immunization in rats immunized by the i.p./i.p. route. In contrast, protection was extended over the 3-month observation period in those immunized by the i.p./p.o. route; the degree of protection was enhanced in rats which received an additional boost at 2 months. These observations establish the fact that immunization with LT is similar to that with cholera toxin in that arousal of the local immune intestinal response by means of peroral immunization provides maximal extended protection. PMID:6987180

  2. Arousal of mucosal secretory immunoglobulin A antitoxin in rats immunized with Escherichia coli heat-labile enterotoxin.

    PubMed Central

    Klipstein, F A; Engert, R F; Clements, J D

    1982-01-01

    Specific serum and mucosal antitoxin levels were determined by enzyme-linked immunosorbent assays in rats immunized with Escherichia coli heat-labile enterotoxin (LT). Immunization by means of a parenteral prime followed by peroral boosts was the only approach that aroused titers of both serum immunoglobulin G (IgG) antitoxin and mucosal secretory IgA antitoxin that were increased fourfold or more over control values. Primary parenteral immunization was effective when given either intraperitoneally or subcutaneously with either Freund complete adjuvant or alum as the adjuvant. The magnitude of the nucosal secretory IgA antitoxin response and the degree of protection against challenge with either LT or viable LT-producing organisms were related to the number and dosage of peroral boosts. LT antigenicity, as determined by enzyme-linked immunosorbent assay, was progressively reduced by toxoiding it with increasing amounts of glutaraldehyde or a carbodiimide; when LT antigenicity was reduced by greater than 50%, the effectiveness of the toxoid in stimulating mucosal antitoxin and providing protection was compromised. Strong protection extended for more than 6 weeks only in rats immunized with a sufficient peroral dosage of LT to arouse mucosal secretory IgA antitoxin titers at least fourfold greater than those of controls. These observations indicate that the ability of LT to stimulate a mucosal secretory IgA antitoxin response is dependent on the antigenicity, route, and dosage of this immunogen; they suggest that the duration of protection in animals immunized by the peroral route is related to the extent of arousal of mucosal secretory IgA antitoxin. PMID:7129629

  3. AZD-3043: A Novel, Metabolically-Labile Sedative/Hypnotic Agent with Rapid and Predictable Emergence from Hypnosis

    PubMed Central

    Egan, Talmage D.; Obara, Shinju; Jenkins, Thomas E.; Jaw-Tsai, Sarah S.; Amagasu, Shanti; Cook, Daniel R.; Steffensen, Scott C.; Beattie, David T.

    2013-01-01

    Background Propofol can be associated with delayed awakening after prolonged infusion. The aim of this study was to characterize the preclinical pharmacology of AZD-3043, a positive allosteric modulator of the γ-aminobutyric acidA (GABAA) receptor containing a metabolically-labile ester moiety. We postulated that its metabolic pathway would result in a short acting clinical profile. Methods The effects of AZD-3043, propofol and propanidid were studied on GABAA receptor-mediated chloride currents in embryonic rat cortical neurons. Radioligand binding studies were also performed. The in vitro stability of AZD-3043 in whole blood and liver microsomes was evaluated. The duration of the loss of righting reflex and effects on the electroencephalograph evoked by bolus or infusion intravenous (IV) administration were assessed in rats. A mixed-effects kinetic-dynamic model using minipigs permitted exploration of the clinical pharmacology of AZD-3043. Results AZD-3043 potentiated GABAA receptor-mediated chloride currents and inhibited [35S]tert-butylbicyclophosphorothionate binding to GABAA receptors. AZD-3043 was rapidly hydrolyzed in liver microsomes from humans and animals. AZD-3043 produced hypnosis and electroencephalograph depression in rats. Compared to propofol, AZD-3043 was shorter acting in rats and pigs. Computer simulation using the porcine kinetic-dynamic model demonstrated that AZD-3043 has very short 50 and 80% decrement times independent of infusion duration. Conclusions AZD-3043 is a positive allosteric modulator of the GABAA receptor in vitro and a sedative/hypnotic agent in vivo. The esterase dependent metabolic pathway results in rapid clearance and short duration of action even for long infusions. AZD-3043 may have clinical potential as a sedative/hypnotic agent with rapid and predictable recovery. PMID:22531340

  4. Regulation of soil organic C mineralisation at the pore scale.

    PubMed

    Ruamps, Léo S; Nunan, Naoise; Pouteau, Valérie; Leloup, Julie; Raynaud, Xavier; Roy, Virginie; Chenu, Claire

    2013-10-01

    Little is known about the factors that regulate C mineralisation at the soil pore scale or how these factors vary throughout the pore network. This study sought to understand how the decomposition of organic carbon varies within the soil pore network and to determine the relative importance of local environmental properties relative to biological properties as controlling factors. This was achieved by sterilising samples of soil and reinoculating them with axenic bacterial suspensions using the matric potential to target different locations in the pore network. Carbon mineralisation curves were described with two-compartment first-order models to distinguish CO2 derived from the labile organic carbon released during sterilisation from CO2 derived from organic C unaffected by sterilisation. The data indicated that the size of the labile pool of organic C, possibly of microbial origin, varied as a function of location in the pore network but that the organic carbon unaffected by sterilisation did not. The mineralisation rate of the labile C varied with the bacterial type inoculated, but the mineralisation rate of the organic C unaffected by sterilisation was insensitive to bacterial type. Taken together, the results suggest that microbial metabolism is a less significant regulator of soil organic carbon decomposition than are microbial habitat properties.

  5. [Affective dependency].

    PubMed

    Scantamburlo, G; Pitchot, W; Ansseau, M

    2013-01-01

    Affective dependency is characterized by emotional distress (insecure attachment) and dependency to another person with a low self-esteem and reassurance need. The paper proposes a reflection on the definition of emotional dependency and the confusion caused by various denominations. Overprotective and authoritarian parenting, cultural and socio-environmental factors may contribute to the development of dependent personality. Psychological epigenetic factors, such as early socio-emotional trauma could on neuronal circuits in prefronto-limbic regions that are essential for emotional behaviour.We also focus on the interrelations between dependent personality, domestic violence and addictions. The objective for the clinician is to propose a restoration of self-esteem and therapeutic strategies focused on autonomy.

  6. Acid-labile sulfides in shallow marine bottom sediments: A review of the impact on ecosystems in the Azov Sea, the NE Black Sea shelf and NW Adriatic lagoons

    NASA Astrophysics Data System (ADS)

    Sorokin, Yu. I.; Zakuskina, O. Yu

    2012-02-01

    Acid-labile sulfides (LS) increase in bottom sediments at sites in the Azov Sea, at the NE Black Sea shelf and in the coastal lagoons of NW Adriatic Sea experiencing direct impacts of anthropogenic pollution. Fresh anthropogenic organic matter stimulates the bacterial sulfate reduction and here the rate of the LS production overcomes their loss during the oxidation and pyritization. This results in the expansion of reduced sediment layer up to the bottom surface. The LS concentration in the reduced sediments varies between 300 and 2000 mg S l -1 of wet silt depending on the size of pollution loading and on the rate of sedimentation. In the oxidized sediments away from the direct pollution impact, the LS concentration did not exceed 100-150 mg S l -1. Being a strong cytochrome toxin, the LS adversely affect the coastal ecosystems. The concentrations over 600 mg S l -1 result in quasi total benthic mortality whereas >300-400 mg S l -1 depletes the benthic faunal abundance and taxonomic diversity. Accumulation of the LS in sediments also induces nocturnal hypoxia and stimulates domination of toxic cyanobacteria in the pelagic phytocenoses.

  7. Treatment with a hybrid between the synapsin ABC domains and the B subunit of E. coli heat-labile toxin reduces frequency of proinflammatory cells and cytokines in the central nervous system of rats with EAE.

    PubMed

    Bibolini, M J; Scerbo, M J; Roth, G A; Monferran, C G

    2014-09-26

    Multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE), are crucially dependent on the invasion of activated autoreactive lymphocytes and blood macrophages into the central nervous system (CNS). Proinflammatory mononuclear cells and activated local microglia mediate inflammation, demyelination and axonal damage at the target organ. Previously, we observed that the administration of a hybrid between the synapsin ABC domains and the B subunit of Escherichia coli heat labile-enterotoxin (LTBABC) to rats with EAE ameliorated disease by modulating the peripheral Th1 response to myelin basic protein (MBP). In the present study, we investigated the effect of LTBABC administration on proinflammatory cell frequency in the CNS of rats with EAE. Treatment with the hybrid in the inductive phase of EAE attenuated disease severity and diminished histological inflammatory infiltrates and demyelination in the spinal cord of rats with acute EAE. Lower frequencies of infiltrating and local macrophages as well as CD4+ T cells that produce the proinflammatory cytokines interferon-gamma (IFN-γ) and interleukin (IL)-17 were found at the target organ. Concomitantly, low levels of INF-γ and IL-17 and increased levels of IL-10 were measured in cultures of CNS infiltrating cells and spinal cord tissue. An increased frequency of CD4+CD25+Foxp3 cells was observed at the disease peak and at the beginning of the recovery stage. These results provide further evidence for the immunomodulatory properties of the fusion protein LTBABC in autoimmune demyelinating disease affecting the central nervous system.

  8. Affective responses to dance.

    PubMed

    Christensen, Julia F; Pollick, Frank E; Lambrechts, Anna; Gomila, Antoni

    2016-07-01

    The objective of the present work was the characterization of mechanisms by which affective experiences are elicited in observers when watching dance movements. A total of 203 dance stimuli from a normed stimuli library were used in a series of independent experiments. The following measures were obtained: (i) subjective measures of 97 dance-naïve participants' affective responses (Likert scale ratings, interviews); and (ii) objective measures of the physical parameters of the stimuli (motion energy, luminance), and of the movements represented in the stimuli (roundedness, impressiveness). Results showed that (i) participants' ratings of felt and perceived affect differed, (ii) felt and perceived valence but not arousal ratings correlated with physical parameters of the stimuli (motion energy and luminance), (iii) roundedness in posture shape was related to the experience of more positive emotion than edgy shapes (1 of 3 assessed rounded shapes showed a clear effect on positiveness ratings while a second reached trend level significance), (iv) more impressive movements resulted in more positive affective responses, (v) dance triggered affective experiences through the imagery and autobiographical memories it elicited in some people, and (vi) the physical parameters of the video stimuli correlated only weakly and negatively with the aesthetics ratings of beauty, liking and interest. The novelty of the present approach was twofold; (i) the assessment of multiple affect-inducing mechanisms, and (ii) the use of one single normed stimulus set. The results from this approach lend support to both previous and present findings. Results are discussed with regards to current literature in the field of empirical aesthetics and affective neuroscience.

  9. Increasing Superoxide Production and the Labile Iron Pool in Tumor Cells may Sensitize Them to Extracellular Ascorbate.

    PubMed

    McCarty, Mark Frederick; Contreras, Francisco

    2014-01-01

    acid with oxygen. An increased pool of labile iron in cancer cells may contribute to the selective susceptibility of many cancers to i.v. ascorbate; antagonism of NF-kappaB activity with salicylate, and intravenous iron administration, could be employed to further elevate free iron in cancers.

  10. Mineralization of organic-matter labile fragments in the humus-accumulative horizon of soddy-podzolic soil

    NASA Astrophysics Data System (ADS)

    Trofimov, S. Ya.; Lazarev, A. S.; Fokin, A. D.

    2012-12-01

    The mineralization rate of the 14C-labeled organic matter (OM) in the humus-accumulative AE horizon of a soddy-podzolic soil was determined in a laboratory experiment. The labeling was performed in a field experiment when microamounts of 14C-labeled glucose, glycine, and uracil were added to tree waste in sacks embedded in the upper layer of the forest litter. Samples containing 14C were taken from the AE horizon (above which the sacks with the labeled material were placed) 7 and 20 months after the beginning of the experiment. The soil samples were wetted to a water content corresponding to ˜80% of the total water capacity and placed in hermetic vessels containing vials with a periodically renewed alkali solution. The incubation was performed at room temperature for 3.5 months; the alkali solutions in the vials were replaced and titrated 12 times during this period. Mineralization curves were plotted from the amounts of carbon dioxide absorbed by a 0.3 N NaOH solution, which were calculated for each time interval; its 14C content was determined by the scintillation method. The experimental treatments also included the determination of the OM mineralization rate in material from the AE horizon pretreated with a heavy liquid or a heavy liquid and a 0.1 N NaOH solution. The differences between the mineralization rates of the labeled organic matter applied to the soil in the form of glucose, glycine, and uracil under the field conditions after the interaction for 7 and 20 months were revealed. The changes in the mineralization rate after the successive extraction of the labile organic matter with a heavy liquid and a 0.1 N NaOH solution were studied. It was shown that the transformation of the labeled low-molecular-weight organic compounds in the soil over 20 months included their strong inclusion into the humus composition, which was confirmed by the similar values of the mineralization constants of the native and 14C-labeled OM. In addition, the treatments with the

  11. Ranking factors affecting emissions of GHG from incubated agricultural soils.

    PubMed

    García-Marco, S; Ravella, S R; Chadwick, D; Vallejo, A; Gregory, A S; Cárdenas, L M

    2014-07-01

    Agriculture significantly contributes to global greenhouse gas (GHG) emissions and there is a need to develop effective mitigation strategies. The efficacy of methods to reduce GHG fluxes from agricultural soils can be affected by a range of interacting management and environmental factors. Uniquely, we used the Taguchi experimental design methodology to rank the relative importance of six factors known to affect the emission of GHG from soil: nitrate (NO3(-)) addition, carbon quality (labile and non-labile C), soil temperature, water-filled pore space (WFPS) and extent of soil compaction. Grassland soil was incubated in jars where selected factors, considered at two or three amounts within the experimental range, were combined in an orthogonal array to determine the importance and interactions between factors with a L16 design, comprising 16 experimental units. Within this L16 design, 216 combinations of the full factorial experimental design were represented. Headspace nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) concentrations were measured and used to calculate fluxes. Results found for the relative influence of factors (WFPS and NO3(-) addition were the main factors affecting N2O fluxes, whilst glucose, NO3(-) and soil temperature were the main factors affecting CO2 and CH4 fluxes) were consistent with those already well documented. Interactions between factors were also studied and results showed that factors with little individual influence became more influential in combination. The proposed methodology offers new possibilities for GHG researchers to study interactions between influential factors and address the optimized sets of conditions to reduce GHG emissions in agro-ecosystems, while reducing the number of experimental units required compared with conventional experimental procedures that adjust one variable at a time.

  12. Ranking factors affecting emissions of GHG from incubated agricultural soils

    PubMed Central

    García-Marco, S; Ravella, S R; Chadwick, D; Vallejo, A; Gregory, A S; Cárdenas, L M

    2014-01-01

    Agriculture significantly contributes to global greenhouse gas (GHG) emissions and there is a need to develop effective mitigation strategies. The efficacy of methods to reduce GHG fluxes from agricultural soils can be affected by a range of interacting management and environmental factors. Uniquely, we used the Taguchi experimental design methodology to rank the relative importance of six factors known to affect the emission of GHG from soil: nitrate (NO3−) addition, carbon quality (labile and non-labile C), soil temperature, water-filled pore space (WFPS) and extent of soil compaction. Grassland soil was incubated in jars where selected factors, considered at two or three amounts within the experimental range, were combined in an orthogonal array to determine the importance and interactions between factors with a L16 design, comprising 16 experimental units. Within this L16 design, 216 combinations of the full factorial experimental design were represented. Headspace nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) concentrations were measured and used to calculate fluxes. Results found for the relative influence of factors (WFPS and NO3− addition were the main factors affecting N2O fluxes, whilst glucose, NO3− and soil temperature were the main factors affecting CO2 and CH4 fluxes) were consistent with those already well documented. Interactions between factors were also studied and results showed that factors with little individual influence became more influential in combination. The proposed methodology offers new possibilities for GHG researchers to study interactions between influential factors and address the optimized sets of conditions to reduce GHG emissions in agro-ecosystems, while reducing the number of experimental units required compared with conventional experimental procedures that adjust one variable at a time. PMID:25177207

  13. Onset of asphyxial state in nonrespiring interval between cord clamping and ventilation increases hemodynamic lability of birth transition in preterm lambs.

    PubMed

    Smolich, Joseph J; Kenna, Kelly R; Cheung, Michael M

    2015-03-15

    Experimentally, a typical ∼2-min cord clamp-to-ventilation interval in preterm lambs is accompanied by increased hemodynamic lability of the birth transition. However, whether this lability is related to development of asphyxia after cord clamping, or can be avoided with a shorter clamp-to-ventilation interval, is unknown. To address these questions, anesthetized preterm fetal lambs (gestation 127 ± 2 days) were instrumented with ductus arteriosus and left pulmonary artery flow probes to obtain right ventricular (RV) output, brachiocephalic trunk and aortic isthmus flow probes to measure left ventricular (LV) output, and aortic trunk catheters for pressure measurement and blood gas analysis. With hemodynamics recorded continuously, fetuses were delivered onto the ewe's abdomen and the cord clamped for 1.5 min before ventilation (n = 8), with aortic sampling at 15, 30, 45, and 60 s, or for 0.5 min, with sampling at 15 s (n = 4). With 1.5-min cord clamping, an asphyxial state (Po2 < 10 mmHg) was evident at ≥45 s, with bradycardia and marked falls in LV and RV outputs (by 60% and 50%, P < 0.001), followed after ventilation onset by tachycardia and LV and RV output surges (4- and 3-fold, P < 0.001). By contrast, heart rate and outputs remained stable after 0.5-min cord clamping, with no postventilation change in heart rate or RV output, and a lesser rise in LV output (22%, P < 0.005). In preterm lambs, rapid development of an asphyxial state within 45 s in the cord clamp-to-ventilation interval increased hemodynamic lability of the birth transition, which was reduced with a shorter (∼0.5 min) cord clamp-to-ventilation interval.

  14. Acid-labile pHPMA modification of four-arm oligoaminoamide pDNA polyplexes balances shielding and gene transfer activity in vitro and in vivo.

    PubMed

    Beckert, Linda; Kostka, Libor; Kessel, Eva; Krhac Levacic, Ana; Kostkova, Hana; Etrych, Tomas; Lächelt, Ulrich; Wagner, Ernst

    2016-08-01

    We report novel pH-reversibly surface-shielded polyplexes with enhanced gene transfer activity upon systemic administration. A four-arm-structured sequence-defined cationic oligomer KK[HK[(H-Sph-K)3HC]2]2 was designed and synthesized on solid-phase, containing additional lysine residues not only for improved pDNA polyplex stability, but also providing attachment points for subsequent polyplex functionalization with amine-reactive shielding polymers. Herein, the surface of polyplexes was shielded with hydrophilic polymers, monovalent PEG or monovalent and multivalent pHPMA, optionally attached to the polyplex via the acid-labile linker AzMMMan. Overall, surface modification with PEG or pHPMA resulted in a decrease in the zeta potential of polyplexes, consistent with the degree of surface shielding. At pH 6.0, only polyplexes modified via the acid-labile linkage showed an increase in zeta potential, consistent with a "deshielding" in acidic environment, expected as beneficial for endosomal escape. Shielding was more efficient for multivalent pHPMA (20kDa, 30kDa) as compared to monovalent pHPMA (10kDa, 20kDa, 30kDa) or PEG (5kDa). In vitro transfection studies revealed higher gene expression by the polyplexes with the acid-labile shield as compared to their irreversibly shielded counterparts. Intravenous administration of AzMMMan-pHPMA modified polyplexes in an in vivo tumor mouse model mediated enhanced gene expression in the subcutaneous tumor and reduced undesirable expression in the liver.

  15. Fate of metals in coastal sediments of a Mediterranean flood-dominated system: An approach based on total and labile fractions

    NASA Astrophysics Data System (ADS)

    Roussiez, Vincent; Ludwig, Wolfgang; Radakovitch, Olivier; Probst, Jean-Luc; Monaco, André; Charrière, Bruno; Buscail, Roselyne

    2011-05-01

    The dynamics of sediment-bound metals (Cs, Cu, Ni, Pb, Ti and Zn) were studied off the Têt River (western Gulf of Lion), a typical Mediterranean coastal river punctuated by short and violent flash-floods. Spatial and temporal sampling strategies were combined to elucidate the fate of these elements in response to both the riverine sediment input and the offshore transport of these sediments through hydrodynamics. Our results show the temporal entrapment of riverborne particles and associated metals, consecutively to a major flood event, in the nearshore sedimentary unit called prodelta. Here, deposition and resuspension mechanisms define a sedimentological cycle that could be followed completely in this study. In terms of speciation between reactive (labile) and residual fractions along the fluvio-deltaic continuum, our results show that Cu, Pb and Zn are the most labile (potentially mobile) metals in the river, in accordance with their contributions from anthropogenic sources. But in the marine surficial sediments, two main behaviours can be discriminated when compared to the riverine suspended particulate matter. While Pb and Zn depict rather a constant labile fraction, Cu is characterized by decreasing levels (up to 50% difference). In terms of environmental impact, these contrasting trends have direct repercussions for the contaminant dispersal in the coastal area. Whereas Pb and Zn conserve their enhanced levels because of their stronger affinity with fine sediments, Cu is marked by the entire loss of its anthropogenic component that is progressively transferred to the dissolved phase, likely mediated by organic ligands. We ascribe these behaviours to different post-depositional partition mechanisms with respect to oxidation of the particulate organic phase at the bottom sediment/water interface. Also, analysis of one sediment core from the prodelta indicates that these early diagenetic processes govern the chemical forms of land-derived contaminants

  16. The contents of labile sulfides in the bottom sediments of the central part of the Sea of Azov: Impact on benthic communities

    NASA Astrophysics Data System (ADS)

    Sorokin, Yu. I.; Burkatskii, O. N.

    2007-10-01

    At 17 stations in the central part of the Sea of Azov, the contents of labile (acid-soluble) sulfides were determined in the upper layer (0-3 cm) of the bottom sediments. At 14 of these stations, the contents of sulfides in the oozy silts were over 300 mg S/dm3 of wet sediment; at seven of the stations, the contents of sulfide were as high as 420-720 mg S/dm3 of wet ooze, or 0.1-0.2% of dry weight. At the other three stations, where neutral matter such as shells and sand prevailed in the samples, the contents of sulfides varied from 80 to 110 mg S/dm3. At these stations, a high density and species diversity of the benthic fauna was retained. At other stations with labile sulfide contents over 200-300 mg S/dm3, the benthos biomass decreased by one or two orders of magnitude. At most of them, it was below 3 g/m2 and the small gastropod Hydrobia tolerant to sulfides dominated. The data obtained show that, in the central part of the Sea of Azov, reduced sediments with high contents of labile sulfides migrate towards the bottom surface, which conforms to the high intensity of the hydrogen sulfide formation process caused by the bacterial sulfate reduction. The study considers the environmental effects of the sulfide contamination of the upper layer of the bottom sediments in the Sea of Azov as a key factor causing the recurrent hypoxy in the near-bottom layers of the water, the suffocation occurrence, and the progressive depletion of the benthic and pelagic fauna.

  17. Endosomal Escape and Transfection Efficiency of PEGylated Cationic Lipid–DNA Complexes Prepared with an Acid-Labile PEG-Lipid

    PubMed Central

    Chan, Chia-Ling; Majzoub, Ramsey N.; Shirazi, Rahau S.; Ewert, Kai K.; Chen, Yen-Ju; Liang, Keng S.

    2012-01-01

    Cationic liposome–DNA (CL–DNA) complexes are being pursued as nonviral gene delivery systems for use in applications that include clinic trials. However, to compete with viral vectors for systemic delivery in vivo, their efficiencies and pharmacokinetics need to be improved. The addition of poly (ethylene glycol)-lipids (PEGylation) prolongs circulation lifetimes of liposomes, but inhibits cellular uptake and endosomal escape of CL–DNA complexes. We show that this limits their transfection efficiency (TE) in a manner dependent on the amount of PEG-lipid, the lipid/DNA charge ratio, and the lipid membrane charge density. To improve endosomal escape of PEGylated CL–DNA complexes, we prepared an acid-labile PEG-lipid (HPEG2K-lipid, PEG MW 2000) which is designed to lose its PEG chains at the pH of late endosomes. The HPEG2K-lipid and a similar but acid-stable PEG-lipid were used to prepare PEGylated CL–DNA complexes. TLC and dynamic light scattering showed that HPEG2K-CL–DNA complexes are stable at pH 7.4 for more than 24 hours, but the PEG chains are cleaved at pH 5 within one hour, leading to complex aggregation. The acid-labile HPEG2K-CL–DNA complexes showed enhanced TE over complexes stabilized with the acid-stable PEG-lipid. Live-cell imaging showed that both types of complexes were internalized to quantitatively similar particle distributions within the first 2 hours of incubation with cells. Thus, we attribute the increased TE of the HPEG2K-CL–DNA complexes to efficient endosomal escape, enabled by the acid-labile HPEG2K-lipid which sheds its PEG chains in the low-pH environment of late endosomes, effectively switching on the electrostatic interactions that promote fusion of the membranes of complex and endosome. PMID:22469293

  18. Psychometric properties of the Wender-Reimherr Adult Attention Deficit Disorder Scale.

    PubMed

    Marchant, Barrie K; Reimherr, Fred W; Robison, Diane; Robison, Reid J; Wender, Paul H

    2013-09-01

    The Wender-Reimherr adult attention deficit disorder scale (WRAADDS; Wender, 1995) is a clinician-rated scale based on the Utah Criteria for attention-deficit/hyperactivity disorder (ADHD) in adults. It assesses ADHD symptom severity across 7 domains: attention difficulties, hyperactivity/restlessness, temper, affective lability, emotional over-reactivity, disorganization, and impulsivity. The normative sample consisted of 120 males and females ages 20-49 with no personal or family history of ADHD. Patients with ADHD met Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; DSM-IV-TR; American Psychiatric Association, 2000) criteria, included males and females ages 20-60, and came from 5 clinical trials. Measures of reliability (test-retest r = .96; interrater r = .75) and internal consistency (Cronbach's alpha = 0.78) were acceptable. The WRAADDS correlated with the Conners' Adult ADHD Rating Scale (CAARS; Conners, Erhardt, & Sparrow, 1999) total scores (r = .501, p < .001). WRAADDS hyperactivity + impulsivity correlated with the CAARS hyperactivity/impulsivity (r = .601, p < .001), and WRAADDS attention + disorganization correlated with the CAARS inattention (r = .430, p < .001). Discriminate validity (adults with vs. without ADHD) was significant for all domains (p < .001). Factor analysis yielded a 2-factor solution accounting for 58% of the variance, one containing the emotional dimensions and the second containing attention and disorganization. Hyperactivity/restlessness and impulsivity were split between both factors. Changes in response to treatment for the WRAADDS and CAARS were highly correlated (p < .001). These psychometric data support continued use of the WRAADDS in adults with ADHD.

  19. Seasonal Dynamics of Soil Labile Organic Carbon and Enzyme Activities in Relation to Vegetation Types in Hangzhou Bay Tidal Flat Wetland.

    PubMed

    Shao, Xuexin; Yang, Wenying; Wu, Ming

    2015-01-01

    Soil labile organic carbon and soil enzymes play important roles in the carbon cycle of coastal wetlands that have high organic carbon accumulation rates. Soils under three vegetations (Phragmites australis, Spartina alterniflora, and Scirpusm mariqueter) as well as bare mudflat in Hangzhou Bay wetland of China were collected seasonally. Seasonal dynamics and correlations of soil labile organic carbon fractions and soil enzyme activities were analyzed. The results showed that there were significant differences among vegetation types in the contents of soil organic carbon (SOC) and dissolved organic carbon (DOC), excepting for that of microbial biomass carbon (MBC). The P. australis soil was with the highest content of both SOC (7.86 g kg-1) and DOC (306 mg kg-1), while the S. mariqueter soil was with the lowest content of SOC (6.83 g kg-1), and the bare mudflat was with the lowest content of DOC (270 mg kg-1). Soil enzyme activities were significantly different among vegetation types except for urease. The P. australis had the highest annual average activity of alkaline phosphomonoesterase (21.4 mg kg-1 h-1), and the S. alterniflora had the highest annual average activities of β-glycosidase (4.10 mg kg-1 h-1) and invertase (9.81 mg g-1 24h-1); however, the bare mudflat had the lowest activities of alkaline phosphomonoesterase (16.2 mg kg-1 h-1), β-glycosidase (2.87 mg kg-1 h-1), and invertase (8.02 mg g-1 24h-1). Analysis also showed that the soil labile organic carbon fractions and soil enzyme activities had distinct seasonal dynamics. In addition, the soil MBC content was significantly correlated with the activities of urease and β-glucosidase. The DOC content was significantly correlated with the activities of urease, alkaline phosphomonoesterase, and invertase. The results indicated that vegetation type is an important factor influencing the spatial-temporal variation of soil enzyme activities and labile organic carbon in coastal wetlands.

  20. Seasonal Dynamics of Soil Labile Organic Carbon and Enzyme Activities in Relation to Vegetation Types in Hangzhou Bay Tidal Flat Wetland

    PubMed Central

    Shao, Xuexin; Yang, Wenying; Wu, Ming

    2015-01-01

    Soil labile organic carbon and soil enzymes play important roles in the carbon cycle of coastal wetlands that have high organic carbon accumulation rates. Soils under three vegetations (Phragmites australis, Spartina alterniflora, and Scirpusm mariqueter) as well as bare mudflat in Hangzhou Bay wetland of China were collected seasonally. Seasonal dynamics and correlations of soil labile organic carbon fractions and soil enzyme activities were analyzed. The results showed that there were significant differences among vegetation types in the contents of soil organic carbon (SOC) and dissolved organic carbon (DOC), excepting for that of microbial biomass carbon (MBC). The P. australis soil was with the highest content of both SOC (7.86 g kg-1) and DOC (306 mg kg-1), while the S. mariqueter soil was with the lowest content of SOC (6.83 g kg-1), and the bare mudflat was with the lowest content of DOC (270 mg kg-1). Soil enzyme activities were significantly different among vegetation types except for urease. The P. australis had the highest annual average activity of alkaline phosphomonoesterase (21.4 mg kg-1 h-1), and the S. alterniflora had the highest annual average activities of β-glycosidase (4.10 mg kg-1 h-1) and invertase (9.81mg g-1 24h-1); however, the bare mudflat had the lowest activities of alkaline phosphomonoesterase (16.2 mg kg-1 h-1), β-glycosidase (2.87 mg kg-1 h-1), and invertase (8.02 mg g-1 24h-1). Analysis also showed that the soil labile organic carbon fractions and soil enzyme activities had distinct seasonal dynamics. In addition, the soil MBC content was significantly correlated with the activities of urease and β-glucosidase. The DOC content was significantly correlated with the activities of urease, alkaline phosphomonoesterase, and invertase. The results indicated that vegetation type is an important factor influencing the spatial-temporal variation of soil enzyme activities and labile organic carbon in coastal wetlands. PMID:26560310

  1. Low Bacterial Diversity and High Labile Organic Matter Concentrations in the Sediments of the Medee Deep-Sea Hypersaline Anoxic Basin

    PubMed Central

    Akoumianaki, Ioanna; Nomaki, Hidetaka; Pachiadaki, Maria; Kormas, Konstantinos Ar.; Kitazato, Hiroshi; Tokuyama, Hidekazu

    2012-01-01

    Studies in the center and margin of the Medee Basin, a Mediterranean deep-sea hypersaline anoxic basin, and at a reference site during Penelope cruise (2007), revealed the existence of a 7 m-thick halocline, with high salinity (328 psu), and high sedimentary organic carbon and biopolymer concentrations. The 194 16S rRNA sequences retrieved were grouped into 118 unique phylotypes. Pseudomonas gessardii, dominated in the center, while 33 phylotypes were detected at the margin and 73 at the reference site. The study suggested conditions hostile to bacteria in the sediments of the Medee Basin and preservation of sedimentary labile organic matter. PMID:22504432

  2. The final deprotection step in oligonucleotide synthesis is reduced to a mild and rapid ammonia treatment by using labile base-protecting groups.

    PubMed Central

    Schulhof, J C; Molko, D; Teoule, R

    1987-01-01

    Phenoxyacetyl (pac) and methoxyacetyl (mac) for adenine and guanine, isobutyryl for cytosine, were successfully applied as amino protecting groups both in phosphotriester and phosphoramidite approaches. As shown by N.M.R. and H.P.L.C. analysis, they are completely deblocked in less than four hours in 29% ammonia at room temperature allowing the preparation of modified DNA containing alkali labile bases such as saturated pyrimidines. The stability of N6-phenoxyacetyl-deoxyadenosine versus depurination in acidic conditions used in the detritylation step was favorably compared with that of the classic N6-benzoyl protected adenine. Images PMID:3822812

  3. Isolation and characterization of the subunits of a heat-labile alpha-amylase inhibitor from Phaseolus vulgaris white kidney bean.

    PubMed

    Yamaguchi, H

    1993-02-01

    The heat-labile one of the two alpha-amylase inhibitors of the white kidney bean (Phaseolus vulgaris) was found to be composed o