Biodiversity of soil bacteria exposed to sub-lethal concentrations of phosphonium-based ionic liquids: Effects of toxicity and biodegradation

DEFF Research Database (Denmark)

Sydow, Mateusz; Owsianiak, Mikołaj; Framski, Grzegorz

2018-01-01

on the structure of microbial community present in an urban park soil in 100-day microcosm experiments. The biodiversity decreased in all samples (Shannon's index decreased from 1.75 down to 0.74 and OTU's number decreased from 1399 down to 965) with the largest decrease observed in the microcosms spiked with ILs...... ILs or their metabolites. Thus, the introduction of phosphonium-based ILs into soils at sub-lethal concentrations may result not only in a decrease in biodiversity due to toxic effects, but also in enrichment with ILs-degrading bacteria....

Sub-lethal effects of energy development on a migratory mammal—The enigma of North American pronghorn

Directory of Open Access Journals (Sweden)

Jon P. Beckmann

2016-04-01

(Pinedale Anticline Project Area [PAPA] and Jonah fields and other behavioral or ecological observations of sub-lethal effects, we failed to reject the null hypothesis that development is unrelated to parity in pronghorn biological responses. Studies intent on producing knowledge to assess whether energy development is inimical or not to ungulates will increasingly require appropriate time scales and understanding whether populations are below an expected food ceiling. Further, as with pronghorn in our study region, knowing if individuals are at the limits of their biological range (e.g. altitude where stressful winter conditions may mask impacts of development is important.

Sub-Lethal Dose of Shiga toxin 2 from Enterohemorrhagic Escherichia coli Affects Balance and Cerebellar Cythoarquitecture.

Directory of Open Access Journals (Sweden)

Luciana eD’Alessio

2016-02-01

Full Text Available Shiga toxin producing Escherichia coli may damage the central nervous system before or concomitantly to manifested hemolytic uremic syndrome symptoms. The cerebellum is frequently damaged during this syndrome, however the deleterious effects of Shiga toxin 2 has never been integrally reported by ultrastructural, physiological and behavioral means. The aim of this study was to determine the cerebellar compromise after intravenous administration of a sub-lethal dose of Shiga toxin 2 by measuring the cerebellar blood brain barrier permeability, behavioral task of cerebellar functionality (inclined plane test, and ultrastructural analysis (transmission electron microscope. Intravenous administration of vehicle (control group, sub-lethal dose of 0.5 ηg and 1 ηg of Stx2 per mouse were tested for behavioral and ultrastructural studies. A set of three independent experiments were performed for each study (n=6. Blood–Brain Barrier resulted damaged and consequently its permeability was significantly increased. Lower scores obtained in the inclined plane task denoted poor cerebellar functionality in comparison to their controls. The most significant lower score was obtained after 5 days of 1ηg of toxin administration. Transmission electron microscope micrographs from the Stx2-treated groups showed neurons with a progressive neurodegenerative condition in a dose dependent manner. As sub-lethal intravenous Shiga toxin 2 altered the blood brain barrier permeability in the cerebellum the toxin penetrated the cerebellar parenchyma and produced cell damaged with significant functional implications in the test balance.

Sub-lethal effects of neonicitinoids on the alfalfa leafcutter bee, Megachile rotundata

Science.gov (United States)

Neonicotinoids are commonly used pesticides in U.S. agriculture. For many beneficial insect species, lethal effects of neonicotinoids are well-documented; however, much less is known about sublethal exposure. The alfalfa leaf cutter bee Megachile rotundata is a managed pollinator that constructs com...

1H NMR metabolomics of earthworm exposure to sub-lethal concentrations of phenanthrene in soil

International Nuclear Information System (INIS)

Brown, Sarah A.E.; McKelvie, Jennifer R.; Simpson, Andre J.; Simpson, Myrna J.

2010-01-01

1 H NMR metabolomics was used to monitor earthworm responses to sub-lethal (50-1500 mg/kg) phenanthrene exposure in soil. Total phenanthrene was analyzed via soxhlet extraction, bioavailable phenanthrene was estimated by hydroxypropyl-β-cyclodextrin (HPCD) and 1-butanol extractions and sorption to soil was assessed by batch equilibration. Bioavailable phenanthrene (HPCD-extracted) comprised ∼65-97% of total phenanthrene added to the soil. Principal component analysis (PCA) showed differences in responses between exposed earthworms and controls after 48 h exposure. The metabolites that varied with exposure included amino acids (isoleucine, alanine and glutamine) and maltose. PLS models indicated that earthworm response is positively correlated to both total phenanthrene concentration and bioavailable (HPCD-extracted) phenanthrene in a freshly spiked, unaged soil. These results show that metabolomics is a powerful, direct technique that may be used to monitor contaminant bioavailability and toxicity of sub-lethal concentrations of contaminants in the environment. These initial findings warrant further metabolomic studies with aged contaminated soils. - 1 H NMR metabolomics is used to directly monitor metabolic responses of Eisenia fetida after 48 h of exposure to sub-lethal concentrations of phenanthrene in soil.

Acute and sub-lethal exposure to copper oxide nanoparticles causes oxidative stress and teratogenicity in zebrafish embryos.

Science.gov (United States)

Ganesan, Santhanamari; Anaimalai Thirumurthi, Naveenkumar; Raghunath, Azhwar; Vijayakumar, Savitha; Perumal, Ekambaram

2016-04-01

Nano-copper oxides are a versatile inorganic material. As a result of their versatility, the immense applications and usage end up in the environment causing a concern for the lifespan of various beings. The ambiguities surround globally on the toxic effects of copper oxide nanoparticles (CuO-NPs). Hence, the present study endeavored to study the sub-lethal acute exposure effects on the developing zebrafish embryos. The 48 hpf LC50 value was about 64 ppm. Therefore, we have chosen the sub-lethal dose of 40 and 60 ppm for the study. Accumulation of CuO-NPs was evidenced from the SEM-EDS and AAS analyzes. The alterations in the AChE and Na(+)/K(+)-ATPase activities disrupted the development process. An increment in the levels of oxidants with a concomitant decrease in the antioxidant enzymes confirmed the induction of oxidative stress. Oxidative stress triggered apoptosis in the exposed embryos. Developmental anomalies were observed with CuO-NPs exposure in addition to oxidative stress in the developing embryos. Decreased heart rate and hatching delay hindered the normal developmental processes. Our work has offered valuable data on the connection between oxidative stress and teratogenicity leading to lethality caused by CuO-NPs. A further molecular mechanism unraveling the uncharted connection between oxidative stress and teratogenicity will aid in the safe use of CuO-NPs. Copyright © 2015 John Wiley & Sons, Ltd.

Chloride and sulphate toxicity to Hydropsyche exocellata (Trichoptera, Hydropsychidae): Exploring intraspecific variation and sub-lethal endpoints

Energy Technology Data Exchange (ETDEWEB)

Sala, Miquel [Centre Tecnològic Forestal de Catalunya - CTFC, Solsona, Catalunya (Spain); Faria, Melissa [CESAM, Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Sarasúa, Ignacio [Technische Universität München, Munich, Bayern (Germany); Barata, Carlos [Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Barcelona (Spain); Bonada, Núria [Grup de Recerca Freshwater Ecology and Management (FEM), Departament d' Ecologia, Facultat de Biologia, Universitat de Barcelona (UB), Diagonal 643, 08028 Barcelona, Catalonia (Spain); Grup de Recerca Freshwater Ecology and Management (FEM), Departament d' Ecologia, Facultat de Biologia, Institut de Recerca de la Biodiversitat (IRBio), Universitat de Barcelona - UB, Diagonal 643, 08028 Barcelona, Catalonia (Spain); Brucet, Sandra [Aquatic Ecology Group, BETA Tecnio Centre, University of Vic - Central University of Catalonia, Vic, Catalonia (Spain); Catalan Institution for Research and Advanced Studies, ICREA, Barcelona 08010 (Spain); Llenas, Laia; Ponsá, Sergio [Aquatic Ecology Group, BETA Tecnio Centre, University of Vic - Central University of Catalonia, Vic, Catalonia (Spain); Prat, Narcís [Grup de Recerca Freshwater Ecology and Management (FEM), Departament d' Ecologia, Facultat de Biologia, Universitat de Barcelona (UB), Diagonal 643, 08028 Barcelona, Catalonia (Spain); Soares, Amadeu M.V.M. [CESAM, Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro (Portugal); and others

2016-10-01

The rivers and streams of the world are becoming saltier due to human activities. In spite of the potential damage that salt pollution can cause on freshwater ecosystems, this is an issue that is currently poorly managed. Here we explored intraspecific differences in the sensitivity of freshwater fauna to two major ions (Cl{sup −} and SO{sub 4}{sup 2−}) using the net-spinning caddisfly Hydropsyche exocellata Dufour 1841 (Trichoptera, Hydropsychidae) as a model organism. We exposed H. exocellata to saline solutions (reaching a conductivity of 2.5 mS cm{sup −1}) with Cl{sup −}:SO{sub 4}{sup 2−} ratios similar to those occurring in effluents coming from the meat, mining and paper industries, which release dissolved salts to rivers and streams in Spain. We used two different populations, coming from low and high conductivity streams. To assess toxicity, we measured sub-lethal endpoints: locomotion, symmetry of the food-capturing nets and oxidative stress biomarkers. According to biomarkers and net building, the population historically exposed to lower conductivities (B10) showed higher levels of stress than the population historically exposed to higher conductivities (L102). However, the differences between populations were not strong. For example, net symmetry was lower in the B10 than in the L102 only 48 h after treatment was applied, and biomarkers showed a variety of responses, with no discernable pattern. Also, treatment effects were rather weak, i.e. only some endpoints, and in most cases only in the B10 population, showed a significant response to treatment. The lack of consistent differences between populations and treatments could be related to the high salt tolerance of H. exocellata, since both populations were collected from streams with relatively high conductivities. The sub-lethal effects tested in this study can offer an interesting and promising tool to monitor freshwater salinization by combining physiological and behavioural bioindicators

Derangement of cellular plasma membranes due to non-lethal radiation doses

International Nuclear Information System (INIS)

Koeteles, G.J.; Kubasova, T.; Somosy, Z.; Horvath, L.

1983-01-01

Earlier observations in the laboratory on fibroblasts and various blood cells of animal and human origins pointed to alteration of concanavalin A binding sites of plasma membranes as well as to concomitant morphological changes and scanning electron microscopic appearance of cell surfaces following sub-lethal doses of X-, fission neutron and beta irradiations. The effects appeared early and existed temporarily; their intensities and the restitution of membrane function depended on radiation doses, types and conditions of cells. In the present paper further aspects of structural and functional derangements of plasma membranes are introduced which were provoked by X- and tritium beta irradiation in the dose range up to 2.5 Gy and in the concentration range from 3.7 kBq/mL, respectively. The state of membrane structure was followed by bindings of various ligands of different receptor requirements, concanavalin A, cationized ferritin and polio virus. In the case of X-irradiation the binding conditions suggest the shift of overall negative surface charges to less negative ones. It was also found that radiation-induced phenomena appear on the cell surface unevenly. Long- and short-term treatments of cells with 3 H-thymidine and 3 H-water also perturb the plasma membrane; beta irradiation affects it directly. Membrane structure and function are suggested to offer good biological models to study correlation of energy deposition and biological effects, both restricted to domains of nanometre range. The data give evidence for radiation-induced membrane alterations in the sub-lethal or non-lethal ranges which might have consequences in the development of stochastic and non-stochastic effects. (author)

1H NMR-Based Metabolomic Analysis of Sub-Lethal Perfluorooctane Sulfonate Exposure to the Earthworm, Eisenia fetida, in Soil

Directory of Open Access Journals (Sweden)

Myrna J. Simpson

2013-08-01

Full Text Available 1H NMR-based metabolomics was used to measure the response of Eisenia fetida earthworms after exposure to sub-lethal concentrations of perfluorooctane sulfonate (PFOS in soil. Earthworms were exposed to a range of PFOS concentrations (five, 10, 25, 50, 100 or 150 mg/kg for two, seven and fourteen days. Earthworm tissues were extracted and analyzed by 1H NMR. Multivariate statistical analysis of the metabolic response of E. fetida to PFOS exposure identified time-dependent responses that were comprised of two separate modes of action: a non-polar narcosis type mechanism after two days of exposure and increased fatty acid oxidation after seven and fourteen days of exposure. Univariate statistical analysis revealed that 2-hexyl-5-ethyl-3-furansulfonate (HEFS, betaine, leucine, arginine, glutamate, maltose and ATP are potential indicators of PFOS exposure, as the concentrations of these metabolites fluctuated significantly. Overall, NMR-based metabolomic analysis suggests elevated fatty acid oxidation, disruption in energy metabolism and biological membrane structure and a possible interruption of ATP synthesis. These conclusions obtained from analysis of the metabolic profile in response to sub-lethal PFOS exposure indicates that NMR-based metabolomics is an excellent discovery tool when the mode of action (MOA of contaminants is not clearly defined.

Critical analysis of the maximum non inhibitory concentration (MNIC) method in quantifying sub-lethal injury in Saccharomyces cerevisiae cells exposed to either thermal or pulsed electric field treatments.

Science.gov (United States)

Kethireddy, V; Oey, I; Jowett, Tim; Bremer, P

2016-09-16

Sub-lethal injury within a microbial population, due to processing treatments or environmental stress, is often assessed as the difference in the number of cells recovered on non-selective media compared to numbers recovered on a "selective media" containing a predetermined maximum non-inhibitory concentration (MNIC) of a selective agent. However, as knowledge of cell metabolic response to injury, population diversity and dynamics increased, the rationale behind the conventional approach of quantifying sub-lethal injury must be scrutinized further. This study reassessed the methodology used to quantify sub-lethal injury for Saccharomyces cerevisiae cells (≈ 4.75 Log CFU/mL) exposed to either a mild thermal (45°C for 0, 10 and 20min) or a mild pulsed electric field treatment (field strengths of 8.0-9.0kV/cm and energy levels of 8, 14 and 21kJ/kg). Treated cells were plated onto either Yeast Malt agar (YM) or YM containing NaCl, as a selective agent at 5-15% in 1% increments. The impact of sub-lethal stress due to initial processing, the stress due to selective agents in the plating media, and the subsequent variation of inhibition following the treatments was assessed based on the CFU count (cell numbers). ANOVA and a generalised least squares model indicated significant effects of media, treatments, and their interaction effects (P<0.05) on cell numbers. It was shown that the concentration of the selective agent used dictated the extent of sub-lethal injury recorded owing to the interaction effects of the selective component (NaCl) in the recovery media. Our findings highlight a potential common misunderstanding on how culture conditions impact on sub-lethal injury. Interestingly for S. cerevisiae cells the number of cells recovered at different NaCl concentrations in the media appears to provide valuable information about the mode of injury, the comparative efficacy of different processing regimes and the inherent degree of resistance within a population. This

{sup 1}H NMR metabolomics of earthworm exposure to sub-lethal concentrations of phenanthrene in soil

Energy Technology Data Exchange (ETDEWEB)

Brown, Sarah A.E.; McKelvie, Jennifer R.; Simpson, Andre J. [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail Toronto, Ontario, M1C 1A4 (Canada); Simpson, Myrna J., E-mail: myrna.simpson@utoronto.c [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail Toronto, Ontario, M1C 1A4 (Canada)

2010-06-15

{sup 1}H NMR metabolomics was used to monitor earthworm responses to sub-lethal (50-1500 mg/kg) phenanthrene exposure in soil. Total phenanthrene was analyzed via soxhlet extraction, bioavailable phenanthrene was estimated by hydroxypropyl-beta-cyclodextrin (HPCD) and 1-butanol extractions and sorption to soil was assessed by batch equilibration. Bioavailable phenanthrene (HPCD-extracted) comprised approx65-97% of total phenanthrene added to the soil. Principal component analysis (PCA) showed differences in responses between exposed earthworms and controls after 48 h exposure. The metabolites that varied with exposure included amino acids (isoleucine, alanine and glutamine) and maltose. PLS models indicated that earthworm response is positively correlated to both total phenanthrene concentration and bioavailable (HPCD-extracted) phenanthrene in a freshly spiked, unaged soil. These results show that metabolomics is a powerful, direct technique that may be used to monitor contaminant bioavailability and toxicity of sub-lethal concentrations of contaminants in the environment. These initial findings warrant further metabolomic studies with aged contaminated soils. - {sup 1}H NMR metabolomics is used to directly monitor metabolic responses of Eisenia fetida after 48 h of exposure to sub-lethal concentrations of phenanthrene in soil.

The effect of sub-lethal damage repair and exchange on the final slope of cell survival curves

International Nuclear Information System (INIS)

Carlone, M.C.; Wilkins, D.E.; Raaphorst, G.P.

2003-01-01

Full text: The Lea-Catcheside dose rate protraction factor, G, is the most widely used model to describe the effects of dose rate on cell survival. In the linear quadratic formalism, this factor modifies the beta component of cell killing; G is greatest for acute irradiations while vanishing at low dose rates. We have found a simple compartmental model that can derive the Lea-Catcheside function. This compartmental model clearly shows that the G function can only be derived using a little known assumption: the diminution of sub-lethal damage due to exchange of repairable lesions is negligible compared to that due to repair. This assumption was explicitly stated by Lea, but it does not appear to have been restated or verified since very early work on cell survival. The implication of this assumption is that sub-lethal damage can be modeled without considering exchange, which is evidenced by the fact that the G function does not contain parameters relating to exchange. By using a new model that fully accounts for repair and exchange of sublethal lesions, a cell survival expression that has a modified G function, but that retains the linear quadratic formalism, can be obtained. At low doses, this new model predicts linear-quadratic behavior, but the behavior gradually changes to mono-exponential at high doses, which is consistent with experimental observations. Modeling cell survival of well-known survival curves using the modified linear quadratic model shows statistically significant improvement in the fits to the cell survival data as compared to best fits obtained with the linear quadratic model. It is shown that these improvements in fits are due to a superior representation of the high dose region of the survival curve

Relative biological effectiveness measurements using murine lethality and survival of intestinal and hematopoietic stem cells after Fermilab neutrons compared to JANUS reactor neutrons and 60Co gamma rays

International Nuclear Information System (INIS)

Hanson, W.R.; Crouse, D.A.; Fry, R.J.M.; Ainsworth, E.J.

1984-01-01

The relative biological effectiveness (RBE) of the 25-MeV (average energy) neutron beam at the Fermi National Accelerator Laboratory was measured using murine bone marrow (LD/sub 50/30/) and gut (LD/sub 50/6/) lethality and killing of hematopoietic colony forming units (CFU-S) or intestinal clonogenic cells (ICC). The LD/sub 50/30/ and LD/sub 50/6/ for mice exposed to the Fermilab neutron beam were 6.6 and 8.7 Gy, respectively, intermediate between those of JANUS neutrons and 60 Co γ rays. The D 0 values for CFU-S and ICC were 47 cGy and 1.05 Gy, respectively, also intermediate between the lowest values found for JANUS neutrons and the highest values found after 60 Co γ rays. The split-dose survival ratios for CFU-S at intervals of 1-6 hr between doses were essentially 1.0 for both neutron sources. The 3-hr split-dose survival ratios for ICC were 1.0 for JANUS neutrons, 1.85 for Fermilab neutrons, and 6.5 for 60 Co γ rays. The RBE estimates for LD/sub 50/30/ were 1.5 and 2.3 for Fermilab and JANUS neutrons, respectively. Based on LD/sub 50/6/, the RBEs were 1.9 (Fermilab) and 3.0 (JANUS). The RBEs for CFU-S D 0 were 1.4 (Fermilab) and 1.9 (JANUS) and for jejunal microcolony D 0 1.4 (Fermilab) and 2.8 (JANUS)

Sub-lethal effects of the neurotoxic pyrethroid insecticide Fastac 50EC on the general motor and locomotor activities of the non-targeted beneficial carabid beetle Platynus assimilis (Coleoptera: Carabidae).

Science.gov (United States)

Tooming, Ene; Merivee, Enno; Must, Anne; Sibul, Ivar; Williams, Ingrid

2014-06-01

Sub-lethal effects of pesticides on behavioural endpoints are poorly studied in carabids (Coleoptera: Carabidae) though changes in behaviour caused by chemical stress may affect populations of these non-targeted beneficial insects. General motor activity and locomotion are inherent in many behavioural patterns, and changes in these activities that result from xenobiotic influence mirror an integrated response of the insect to pesticides. Influence of pyrethroid insecticides over a wide range of sub-lethal doses on the motor activities of carabids still remains unclear. Video tracking of Platynus assimilis showed that brief exposure to alpha-cypermethrin at sub-lethal concentrations ranged from 0.01 to 100 mg L(-1) caused initial short-term (24 h) locomotor hypo-activity. In addition, significant short- and long-term concentration and time-dependent changes occurred in general motor activity patterns and rates. Conspicuous changes in motor activity of Platynus assimilis beetles treated at alpha-cypermethrin concentrations up to 75,000-fold lower than maximum field recommended concentration (MFRC) suggest that many, basic fitness-related behaviours might be severely injured as well. These changes may negatively affect carabid populations in agro-ecosystems. Long-term hypo-activity could directly contribute to decreased trap captures of carabids frequently observed after insecticide application in the field. © 2013 Society of Chemical Industry.

The radiobiology of laser-driven particle beams: focus on sub-lethal responses of normal human cells

International Nuclear Information System (INIS)

Manti, L.; Perozziello, F.M.; Romagnani, L.; Borghesi, M.; Doria, D.; Candiano, G.; Cirrone, G.A.P.; Leanza, R.; Romano, F.; Scuderi, V.; Tramontana, A.; Chaudhary, P.; Gwynne, D.; Prise, K. M.

2017-01-01

Accelerated proton beams have become increasingly common for treating cancer. The need for cost and size reduction of particle accelerating machines has led to the pioneering investigation of optical ion acceleration techniques based on laser-plasma interactions as a possible alternative. Laser-matter interaction can produce extremely pulsed particle bursts of ultra-high dose rates (≥ 10 9 Gy/s), largely exceeding those currently used in conventional proton therapy. Since biological effects of ionizing radiation are strongly affected by the spatio-temporal distribution of DNA-damaging events, the unprecedented physical features of such beams may modify cellular and tissue radiosensitivity to unexplored extents. Hence, clinical applications of laser-generated particles need thorough assessment of their radiobiological effectiveness. To date, the majority of studies have either used rodent cell lines or have focussed on cancer cell killing being local tumour control the main objective of radiotherapy. Conversely, very little data exist on sub-lethal cellular effects, of relevance to normal tissue integrity and secondary cancers, such as premature cellular senescence. Here, we discuss ultra-high dose rate radiobiology and present preliminary data obtained in normal human cells following irradiation by laser-accelerated protons at the LULI PICO2000 facility at Laser Lab Europe, France.

Lethal and Sublethal Effects of Fenpropathrin on the Biological Performance of Scolothrips longicornis (Thysanoptera: Thripidae)

DEFF Research Database (Denmark)

Pakyari, Hajar; Enkegaard, Annie

2013-01-01

Determination of negative nontarget effects of pesticides on beneficial organisms by measuring only lethal effects is likely to underestimate effects of sublethal doses. In this study, the sublethal effects of fenpropathrin on the predatory thrips Scolothrips longicornis Priesner (Thysanoptera: T...

Dose-response tests and semi-field evaluation of lethal and sub-lethal effects of slow release pyriproxyfen granules (Sumilarv®0.5G) for the control of the malaria vectors Anopheles gambiae sensu lato.

Science.gov (United States)

Mbare, Oscar; Lindsay, Steven W; Fillinger, Ulrike

2013-03-14

Recently research has shown that larviciding can be an effective tool for integrated malaria vector control. Nevertheless, the uptake of this intervention has been hampered by the need to re-apply larvicides frequently. There is a need to explore persistent, environmentally friendly larvicides for malaria vector control to reduce intervention efforts and costs by reducing the frequency of application. In this study, the efficacy of a 0.5% pyriproxyfen granule (Surmilarv®0.5G, Sumitomo Chemicals) was assessed for the control of Anopheles gambiae sensu stricto and Anopheles arabiensis, the major malaria vectors in sub-Saharan Africa. Dose-response and standardized field tests were implemented following standard procedures of the World Health Organization's Pesticide Evaluation Scheme to determine: (i) the susceptibility of vectors to this formulation; (ii) the residual activity and appropriate retreatment schedule for field application; and, (iii) sub-lethal impacts on the number and viability of eggs laid by adults after exposure to Sumilarv®0.5G during larval development. Anopheles gambiae s.s. and An. arabiensis were highly susceptible to Sumilarv®0.5G. Estimated emergence inhibition (EI) values were very low and similar for both species. The minimum dosage that completely inhibited adult emergence was between 0.01-0.03 parts per million (ppm) active ingredient (ai). Compared to the untreated control, an application of 0.018 ppm ai prevented 85% (95% confidence interval (CI) 82%-88%) of adult emergence over six weeks under standardized field conditions. A fivefold increase in dosage of 0.09 ppm ai prevented 97% (95% CI 94%-98%) emergence. Significant sub-lethal effects were observed in the standardized field tests. Female An. gambiae s.s. that were exposed to 0.018 ppm ai as larvae laid 47% less eggs, and females exposed to 0.09 ppm ai laid 74% less eggs than females that were unexposed to the treatment. Furthermore, 77% of eggs laid by females exposed to 0

Dose–response tests and semi-field evaluation of lethal and sub-lethal effects of slow release pyriproxyfen granules (Sumilarv®0.5G) for the control of the malaria vectors Anopheles gambiae sensu lato

Science.gov (United States)

2013-01-01

Background Recently research has shown that larviciding can be an effective tool for integrated malaria vector control. Nevertheless, the uptake of this intervention has been hampered by the need to re-apply larvicides frequently. There is a need to explore persistent, environmentally friendly larvicides for malaria vector control to reduce intervention efforts and costs by reducing the frequency of application. In this study, the efficacy of a 0.5% pyriproxyfen granule (Surmilarv®0.5G, Sumitomo Chemicals) was assessed for the control of Anopheles gambiae sensu stricto and Anopheles arabiensis, the major malaria vectors in sub-Saharan Africa. Methods Dose–response and standardized field tests were implemented following standard procedures of the World Health Organization’s Pesticide Evaluation Scheme to determine: (i) the susceptibility of vectors to this formulation; (ii) the residual activity and appropriate retreatment schedule for field application; and, (iii) sub-lethal impacts on the number and viability of eggs laid by adults after exposure to Sumilarv®0.5G during larval development. Results Anopheles gambiae s.s. and An. arabiensis were highly susceptible to Sumilarv®0.5G. Estimated emergence inhibition (EI) values were very low and similar for both species. The minimum dosage that completely inhibited adult emergence was between 0.01-0.03 parts per million (ppm) active ingredient (ai). Compared to the untreated control, an application of 0.018 ppm ai prevented 85% (95% confidence interval (CI) 82%-88%) of adult emergence over six weeks under standardized field conditions. A fivefold increase in dosage of 0.09 ppm ai prevented 97% (95% CI 94%-98%) emergence. Significant sub-lethal effects were observed in the standardized field tests. Female An. gambiae s.s. that were exposed to 0.018 ppm ai as larvae laid 47% less eggs, and females exposed to 0.09 ppm ai laid 74% less eggs than females that were unexposed to the treatment. Furthermore, 77

Chloride and sulphate toxicity to Hydropsyche exocellata (Trichoptera, Hydropsychidae): Exploring intraspecific variation and sub-lethal endpoints

International Nuclear Information System (INIS)

Sala, Miquel; Faria, Melissa; Sarasúa, Ignacio; Barata, Carlos; Bonada, Núria; Brucet, Sandra; Llenas, Laia; Ponsá, Sergio; Prat, Narcís; Soares, Amadeu M.V.M.

2016-01-01

The rivers and streams of the world are becoming saltier due to human activities. In spite of the potential damage that salt pollution can cause on freshwater ecosystems, this is an issue that is currently poorly managed. Here we explored intraspecific differences in the sensitivity of freshwater fauna to two major ions (Cl"− and SO_4"2"−) using the net-spinning caddisfly Hydropsyche exocellata Dufour 1841 (Trichoptera, Hydropsychidae) as a model organism. We exposed H. exocellata to saline solutions (reaching a conductivity of 2.5 mS cm"−"1) with Cl"−:SO_4"2"− ratios similar to those occurring in effluents coming from the meat, mining and paper industries, which release dissolved salts to rivers and streams in Spain. We used two different populations, coming from low and high conductivity streams. To assess toxicity, we measured sub-lethal endpoints: locomotion, symmetry of the food-capturing nets and oxidative stress biomarkers. According to biomarkers and net building, the population historically exposed to lower conductivities (B10) showed higher levels of stress than the population historically exposed to higher conductivities (L102). However, the differences between populations were not strong. For example, net symmetry was lower in the B10 than in the L102 only 48 h after treatment was applied, and biomarkers showed a variety of responses, with no discernable pattern. Also, treatment effects were rather weak, i.e. only some endpoints, and in most cases only in the B10 population, showed a significant response to treatment. The lack of consistent differences between populations and treatments could be related to the high salt tolerance of H. exocellata, since both populations were collected from streams with relatively high conductivities. The sub-lethal effects tested in this study can offer an interesting and promising tool to monitor freshwater salinization by combining physiological and behavioural bioindicators. - Highlights: • We assessed Cl

Lethal and sub-lethal chronic effects of the herbicide diuron on seagrass

Energy Technology Data Exchange (ETDEWEB)

Negri, Andrew P., E-mail: a.negri@aims.gov.au [Australian Institute of Marine Science, Townsville, Queensland 4810 (Australia); Flores, Florita [Australian Institute of Marine Science, Townsville, Queensland 4810 (Australia); Mercurio, Phil [Australian Institute of Marine Science, Townsville, Queensland 4810 (Australia); University of Queensland and National Research Centre for Environmental Toxicology, Coopers Plains, Queensland 4108 (Australia); Mueller, Jochen F. [University of Queensland and National Research Centre for Environmental Toxicology, Coopers Plains, Queensland 4108 (Australia); Collier, Catherine J. [Centre for Tropical Water & Aquatic Ecosystem Research (TropWATER), James Cook University, Cairns, Queensland 4870 (Australia)

2015-08-15

Highlights: • We performed chronic exposures of two seagrass species to the herbicide diuron. • Diuron affected photosystem II (PSII) at 0.3 μg l{sup −1} and growth at 7.2 μg l{sup −1}. • Biomarkers indicated that carbon-assimilation from photosynthesis dropped following 0.6 μg l{sup −1} diuron exposure. • Energetic reserves in the seagrass were halved at 1.7 μg l{sup −1} after 11 weeks. • Chronic exposure to diuron is likely to enhance the impacts of low light stress during flood plumes - Abstract: Photosystem II herbicides from agricultural sources have been detected throughout nearshore tropical habitats including seagrass meadows. While PSII herbicides have been shown to inhibit growth in microalgae at low concentrations, the potential impacts of chronic low concentration exposures to seagrass health and growth have not been investigated. Here we exposed two tropical seagrass species Halodule uninervis and Zostera muelleri to elevated diuron concentrations (from 0.3 to 7.2 μg l{sup −1}) over a 79-day period followed by a 2-week recovery period in uncontaminated seawater. PAM fluorometry demonstrated rapid effect of diuron on photosystem II (PSII) in both seagrass species at 0.3 μg l{sup −1}. This effect included significant inhibition of photosynthetic efficiency (ΔF/F{sub m}′) and inactivation of PSII (F{sub v}/F{sub m}) over the 11 week exposure period. Significant mortality and reductions in growth was only observed at the highest exposure concentration of 7.2 μg l{sup −1} diuron. However, biochemical indicators demonstrated that the health of seagrass after this prolonged exposure was significantly compromised at lower concentrations. For example, the drop in C:N ratios (0.6 μg l{sup −1}) and reduced δ{sup 13}C (1.7 μg l{sup −1}) in seagrass leaves indicated reduced C-assimilation from photosynthesis. Critically, the energetic reserves of the plants (as measured by starch content in the root-rhizome complex) were

Sub-lethal irradiation of human colorectal tumor cells imparts enhanced and sustained susceptibility to multiple death receptor signaling pathways.

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Victoria Ifeadi

Full Text Available BACKGROUND: Death receptors (DR of the TNF family function as anti-tumor immune effector molecules. Tumor cells, however, often exhibit DR-signaling resistance. Previous studies indicate that radiation can modify gene expression within tumor cells and increase tumor cell sensitivity to immune attack. The aim of this study is to investigate the synergistic effect of sub-lethal doses of ionizing radiation in sensitizing colorectal carcinoma cells to death receptor-mediated apoptosis. METHODOLOGY/PRINCIPAL FINDINGS: The ability of radiation to modulate the expression of multiple death receptors (Fas/CD95, TRAILR1/DR4, TRAILR2/DR5, TNF-R1 and LTβR was examined in colorectal tumor cells. The functional significance of sub-lethal doses of radiation in enhancing tumor cell susceptibility to DR-induced apoptosis was determined by in vitro functional sensitivity assays. The longevity of these changes and the underlying molecular mechanism of irradiation in sensitizing diverse colorectal carcinoma cells to death receptor-mediated apoptosis were also examined. We found that radiation increased surface expression of Fas, DR4 and DR5 but not LTβR or TNF-R1 in these cells. Increased expression of DRs was observed 2 days post-irradiation and remained elevated 7-days post irradiation. Sub-lethal tumor cell irradiation alone exhibited minimal cell death, but effectively sensitized three of three colorectal carcinoma cells to both TRAIL and Fas-induced apoptosis, but not LTβR-induced death. Furthermore, radiation-enhanced Fas and TRAIL-induced cell death lasted as long as 5-days post-irradiation. Specific analysis of intracellular sensitizers to apoptosis indicated that while radiation did reduce Bcl-X(L and c-FLIP protein expression, this reduction did not correlate with the radiation-enhanced sensitivity to Fas and/or TRAIL mediated apoptosis among the three cell types. CONCLUSIONS/SIGNIFICANCE: Irradiation of tumor cells can overcome Fas and TRAIL

The involvement of IL-17A in the murine response to sub-lethal inhalational infection with Francisella tularensis.

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Gal Markel

2010-06-01

Full Text Available Francisella tularensis is an intercellular bacterium often causing fatal disease when inhaled. Previous reports have underlined the role of cell-mediated immunity and IFNgamma in the host response to Francisella tularensis infection.Here we provide evidence for the involvement of IL-17A in host defense to inhalational tularemia, using a mouse model of intranasal infection with the Live Vaccine Strain (LVS. We demonstrate the kinetics of IL-17A production in lavage fluids of infected lungs and identify the IL-17A-producing lymphocytes as pulmonary gammadelta and Th17 cells. The peak of IL-17A production appears early during sub-lethal infection, it precedes the peak of immune activation and the nadir of the disease, and then subsides subsequently. Exogenous airway administration of IL-17A or of IL-23 had a limited yet consistent effect of delaying the onset of death from a lethal dose of LVS, implying that IL-17A may be involved in restraining the infection. The protective role for IL-17A was directly demonstrated by in vivo neutralization of IL-17A. Administration of anti IL-17A antibodies concomitantly to a sub-lethal airway infection with 0.1xLD(50 resulted in a fatal disease.In summary, these data characterize the involvement and underline the protective key role of the IL-17A axis in the lungs from inhalational tularemia.

One-pot synthesis of strongly fluorescent DNA-CuInS{sub 2} quantum dots for label-free and ultrasensitive detection of anthrax lethal factor DNA

Energy Technology Data Exchange (ETDEWEB)

Liu, Ziping; Su, Xingguang, E-mail: suxg@jlu.edu.cn

2016-10-26

Herein, high quality DNA-CuInS{sub 2} QDs are facilely synthesized through a one-pot hydrothermal method with fluorescence quantum yield as high as 23.4%, and the strongly fluorescent DNA-CuInS{sub 2} QDs have been utilized as a novel fluorescent biosensor for label-free and ultrasensitive detection of anthrax lethal factor DNA. L-Cysteine (L-Cys) and a specific-sequence DNA are used as co-ligands to stabilize the CuInS{sub 2} QDs. The specific-sequence DNA consists of two domains: phosphorothiolates domain (sulfur-containing variants of the usual phosphodiester backbone) controls the nanocrystal passivation and serves as a ligand, and the functional domain (non-phosphorothioates) controls the biorecognition. The as-prepared DNA-CuInS{sub 2} QDs have high stability, good water-solubility and low toxicity. Under the optimized conditions, a linear correlation was established between the fluorescence intensity ratio I/I{sub 0} (I{sub 0} is the original fluorescence intensity of DNA-CuInS{sub 2} QDs, and I is the fluorescence intensity of DNA-CuInS{sub 2} QDs/GO with the addition of various concentrations of anthrax lethal factor DNA) and the concentration of anthrax lethal factor DNA in the range of 0.029–0.733 nmol L{sup −1} with a detection limit of 0.013 nmol L{sup −1}. The proposed method has been successfully applied to the determination of anthrax lethal factor DNA sequence in human serum samples with satisfactory results. Because of low toxicity and fine biocompatibility, DNA-CuInS{sub 2} QDs also hold potential applications in bioimaging. - Highlights: • Strongly fluorescent DNA-QDs were successfully prepared by a one-pot hydrothermal method with quantum yield up to 23.4%. • A biosensor for label-free detection of anthrax lethal factor DNA was established based on the as-prepared DNA-QDs. • The DNA sensor took advantage of the feature that ssDNA binds to GO with significantly higher affinity than dsDNA. • Good sensitivity and selectivity were

Maize lethal necrosis (MLN), an emerging threat to maize-based food security in sub-Saharan Africa

Science.gov (United States)

In sub-Saharan Africa, maize is a staple food and key determinant of food security for smallholder farming communities. Pest and disease outbreaks are key constraints to maize productivity. In September 2011, a serious disease outbreak, later diagnosed as maize lethal necrosis (MLN), was reported on...

The Effect of A Single Sub-Lethal Dose of Whole Body Irradiation on the Small Intestine of Rats

International Nuclear Information System (INIS)

Al-Ramli, M. A.; Kubba, M. A.; Al-Bassam, L. S.; Belhaj, K.; Al-shawish, N. M.

2007-01-01

The effect of whole body radiation with a single sub-lethal dose at 4 Gy on rat small intestine was studied histologically and quantitatively. Irradiated animals were euthanized at 24 hours, 3, 7, 14, 21 and 28 days post- irradiation. Crypts of Leiberkuhn and peyer's patches were especially targeted by irradiation. The crypts showed severe cellular fragmentation in the germinal cellular compartments twenty Four hours after irradiation resulting in partial denudation of villi especially at their Tips. At three days, these cells resumed their proliferative activity with the appearance of unusually large numbers of mitotic figures. Cellular regeneration in the crypts and on the villous surface showed improvement with advancing time till day 28 when the villi had complete epithelial covering and the proliferative activity of the germinal cryptic cells returned to normal. The quantitative study included the measurement of about fifty villi at each time after irradiation. A significant decrease in villous length was noticed at twenty four hours post-irradiation compared to the control values. The length of villi plateaued at about this level till day twenty one when it slightly increased to reach a sub normal mean length on day 28. We concluded that whole body irradiation with a single dose at 4 Gy was enough to induce cryptic cellular necrosis with sloughing of epithelial villous columnar covering. This cellular damage was, however, sub- total since quick regenerative cellular activity was noticed three days post-irradiation. The decrease in the villous length paralleled the cryptic cellular damage whereas full recovery was not achieved despite obvious cellular regeneration.

Experimental evaluation of the relationship between lethal or non-lethal virulence and transmission success in malaria parasite infections

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Nithiuthai S

2004-09-01

Full Text Available Abstract Background Evolutionary theory suggests that the selection pressure on parasites to maximize their transmission determines their optimal host exploitation strategies and thus their virulence. Establishing the adaptive basis to parasite life history traits has important consequences for predicting parasite responses to public health interventions. In this study we examine the extent to which malaria parasites conform to the predicted adaptive trade-off between transmission and virulence, as defined by mortality. The majority of natural infections, however, result in sub-lethal virulent effects (e.g. anaemia and are often composed of many strains. Both sub-lethal effects and pathogen population structure have been theoretically shown to have important consequences for virulence evolution. Thus, we additionally examine the relationship between anaemia and transmission in single and mixed clone infections. Results Whereas there was a trade-off between transmission success and virulence as defined by host mortality, contradictory clone-specific patterns occurred when defining virulence by anaemia. A negative relationship between anaemia and transmission success was found for one of the parasite clones, whereas there was no relationship for the other. Notably the two parasite clones also differed in a transmission phenotype (gametocyte sex ratio that has previously been shown to respond adaptively to a changing blood environment. In addition, as predicted by evolutionary theory, mixed infections resulted in increased anaemia. The increased anaemia was, however, not correlated with any discernable parasite trait (e.g. parasite density or with increased transmission. Conclusions We found some evidence supporting the hypothesis that there is an adaptive basis correlating virulence (as defined by host mortality and transmission success in malaria parasites. This confirms the validity of applying evolutionary virulence theory to biomedical

Dominant lethal effect of gamma radiation of 60Co in Biomphalaria glabrata (SAY, 1818)

International Nuclear Information System (INIS)

Tallarico, Lenita de Freitas

2003-01-01

Germ cell mutations are used in ecotoxicological studies as biomarkers of population effects and indicators of ecological changes. Biomphalaria glabrata, a freshwater mollusk, is a good experimental model for biomonitoring studies due to its biological characteristics and the ecological importance of this invertebrate group. The dominant lethal test was established in B. glabrata for the detection of germ cell mutations. Results with chemical mutagens showed that this system is efficient, specific and sensitive in the evaluation of germ cell mutations induced by reference mutagens. In this work, the dominant lethal effects of gamma radiation of 60 Co were studied. A preliminary experiment was done to establish the dose range and to estimate the chronology of spermatogenesis in B. glabrata. This estimate is possible because of the uniformity in response to ionizing radiation between germ cells at homologous stages of spermatogenesis in widely different species. In general, pre-meiotic germ cells are less sensitive to the induction of lethal dominant mutations than post-meiotic cells. This effect can be attributed to: young gametogenic cells - mitotically active - have greater repair ability from sub-lethal DNA damage and there is a selective elimination of the damaged cells. In our system: induction of lethal dominant mutations causes an increase in the frequency of malformations and, cytotoxic effect is displayed as a reduction in the crossing rates. Total duration of spermatogenesis was estimated in approximately 36 days, with the following distribution of stages: 1 to 13 days - spermatogonia, 14 to 20 days - spermatocytes, 21 to 36 days - spermatids and spermatozoa. Based on this chronology, irradiated wild-type snails with 2,5; 10 and 20Gy and crossed with non-irradiated albino snails after 7, 17, 23, 30 and 36 days. The frequencies of malformations in the heterozygous wild-type offspring of the nonirradiated albino snails were used as indicator of germ cell

Epithelial Plasticity in Castration-Resistant Prostate Cancer: Biology of the Lethal Phenotype

Science.gov (United States)

2011-07-01

647, cytokeratin (AbD Serotec #MCA 1907HT) labeled with Alexa 555, and Vimentin (BD Biosciences, San Jose , CA #550513) labeled with Alexa 488. Nuclear...importance of the transitional phenotypic state to lethal cancer biology. In: Proceedings of the Genitourinary Cancers Symposium; 5–7 March 2010; San ...resulting gene list was used to determine the significantly differentially expressed genes between AT3-M and AT3-T using the "Filtering on Volcano

Sub-lethal toxicity of chlorpyrifos on Common carp, Cyprinus carpio (Linnaeus, 1758: Biochemical response

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Mahdi Banaee

2014-01-01

Full Text Available Chlorpyrifos, an organophosphate pesticide, is widely used to control pests in agriculture farms and orchards of fruit trees. In this study, the fish were exposed to sub-lethal concentrations of chlorpyrifos which were determined based on numerical value of 96 h LC50. Blood was sampled after 10, 20 and 30 days and biochemical parameters including glucose, total protein, albumin, globulin, triglyceride and cholesterol levels, and aspartate aminotransferase (AST, alanine aminotransferase (ALT, lactate dehydrogenase (LDH, creatine kinase (CK, alkaline phosphatase (ALP and acetylcholinsetrase (AChE activities were measured. Behavioral changes in the fish were also recorded during the experiment. Unbalanced swimming, swimming in the surface water and hyperglycemia, increased blood triglyceride, and increased levels of AST, LDH and CK activities as well as decreased levels of AChE activity were important changes that were observed in the specimens exposed to chlorpyrifos during experimental periods. The most important alterations in the blood biochemical parameters were measured in the specimens exposed to 40 µg/L chlorpyrifos on the 20th and 30th day of the trial. In conclusion, results of the present study indicated that exposure to sub-lethal concentrations of chlorpyrifos as low as 40 µg/L may cause biochemical and behavioral changes in Cyprinus carpio.

Sub-lethal cadmium exposure increases phytochelatin concentrations in the aquatic snail Lymnaea stagnalis

Energy Technology Data Exchange (ETDEWEB)

SF, Gonçalves [Department of Biology & CESAM, Centre for Environmental and Marine Studies, University of Aveiro, 3810-193 Aveiro (Portugal); SK, Davies [Department of Surgery and Cancer, Imperial College London, Sir Alexander Fleming Building, London SW7 2AZ (United Kingdom); Bennett, M. [Department of Life Sciences, Imperial College London, Sir Alexander Fleming Building, London SW7 2AZ (United Kingdom); Raab, A.; Feldmann, J. [TESLA, Department of Chemistry, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, Scotland (United Kingdom); Kille, P. [Cardiff School of Biosciences, Cardiff University, Park Place, Cardiff CF10 3US (United Kingdom); Loureiro, S. [Department of Biology & CESAM, Centre for Environmental and Marine Studies, University of Aveiro, 3810-193 Aveiro (Portugal); DJ, Spurgeon [Centre for Ecology and Hydrology, Maclean Building, Benson Lane, Wallingford OX10 8BB (United Kingdom); JG, Bundy, E-mail: j.bundy@imperial.ac.uk [Department of Surgery and Cancer, Imperial College London, Sir Alexander Fleming Building, London SW7 2AZ (United Kingdom)

2016-10-15

Phytochelatins are metal-binding metabolites found in almost all plant species and some animal groups, including nematodes and annelids, where they can play an important role in detoxifying metals such as cadmium. Species from several other taxa contain a phytochelatin synthase (PCS) gene orthologue, including molluscs, indicating they may have the potential to synthesize phytochelatins. However, the presence of a gene alone does not demonstrate that it plays a functional role in metal detoxification. In the present study, we show that the aquatic snail Lymnaea stagnalis produced both penta- and heptapeptide phytochelatins (i.e. phytochelatin-2 and phytochelatin-3), and their levels increased in response to sub-lethal levels of cadmium. - Highlights: • Little is known about the role of phytochelatins in metal detoxification in animals. • We detected phytochelatins (PC{sub 2} and PC{sub 3}) in a mollusc species, Lymnaea stagnalis. • Phytochelatins increased in Lymnaea stagnalis when exposed to cadmium. • Future research on phytochelatin responses in molluscs would be valuable.

Exploring biological effects of MoS{sub 2} nanosheets on native structures of α-helical peptides

Energy Technology Data Exchange (ETDEWEB)

Gu, Zonglin; Li, Weifeng, E-mail: wfli@suda.edu.cn, E-mail: ruhong@us.ibm.com [School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123 (China); Hong, Linbi [Computational Biological Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Zhou, Ruhong, E-mail: wfli@suda.edu.cn, E-mail: ruhong@us.ibm.com [School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123 (China); Computational Biological Center, IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Department of Chemistry, Columbia University, New York, New York 10027 (United States)

2016-05-07

Recent reports of mono- and few-layer molybdenum disulfide (MoS{sub 2}), a representative transition metal dichacogenide (TMD), as antibacterial and anticancer agents have shed light on their potential in biomedical applications. To better facilitate these promising applications, one needs to understand the biological effects of these TMDs as well, such as their potential adverse effects on protein structure and function. Here, we sought to understand the interaction of MoS{sub 2} nanosheets with peptides using molecular dynamics simulations and a simple model polyalanine with various lengths (PA{sub n}, n = 10, 20, 30, and 40; mainly α − helices). Our results demonstrated that MoS{sub 2} monolayer has an exceptional capability to bind all peptides in a fast and strong manner. The strong attraction from the MoS{sub 2} nanosheet is more than enough to compensate the energy needed to unfold the peptide, regardless of the length, which induces drastic disruptions to the intra-peptide hydrogen bonds and subsequent secondary structures of α − helices. This universal phenomenon may point to the potential nanotoxicity of MoS{sub 2} when used in biological systems. Moreover, these results aligned well with previous findings on the potential cytotoxicity of TMD nanomaterials.

Effects of Sub-lethal Concentrations of Silver Nanoparticles on a Simulated Intestinal Prokaryotic–Eukaryotic Interface

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Elisa Garuglieri

2018-01-01

Full Text Available Nanotechnology applications are expected to bring a range of benefits to the food sector, aiming to provide better quality and conservation. In this research, the physiological response of both an Escherichia coli mono-species biofilm and Caco-2 intestinal cells to sub-lethal concentrations of silver nanoparticles (AgNPs has been investigated. In order to simulate the anaerobic and aerobic compartments required for bacteria and intestinal cells growth, a simplified semi-batch model based on a transwell permeable support was developed. Interaction between the two compartments was obtained by exposing Caco-2 intestinal cells to the metabolites secreted by E. coli biofilm after its exposure to AgNPs. To the best of the authors’ knowledge, this study is the first to investigate the effect of AgNPs on Caco-2 cells that takes into consideration previous AgNP-intestinal biofilm interactions, and at concentrations mimicking real human exposure. Our data show that 1 μg/mL AgNPs in anaerobic conditions (i promote biofilm formation up to 2.3 ± 0.3 fold in the first 72 h of treatment; (ii increase reactive oxygen species (ROS production to 84 ± 21% and change the physiological status of microbial cells after 96 h of treatment; (iii seriously affect a 72-h old established biofilm, increasing the level of oxidative stress to 86 ± 21%. Moreover, the results indicate that oxygen renders the biofilm more adequate to counteract AgNP effects. Comet assays on Caco-2 cells demonstrated a protective role of biofilm against the genotoxic effect of 1 μg/mL AgNPs on intestinal epithelial cells.

In Vitro Evaluation of Sub-Lethal Concentrations of Plant-Derived Antifungal Compounds on FUSARIA Growth and Mycotoxin Production

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Caterina Morcia

2017-07-01

Full Text Available Phytopathogenic fungi can lead to significant cereal yield losses, also producing mycotoxins dangerous for human and animal health. The fungal control based on the use of synthetic fungicides can be complemented by "green" methods for crop protection, based on the use of natural products. In this frame, the antifungal activities of bergamot and lemon essential oils and of five natural compounds recurrent in essential oils (citronellal, citral, cinnamaldehyde, cuminaldehyde and limonene have been evaluated against three species of mycotoxigenic fungi (Fusarium sporotrichioides, F. graminearum and F. langsethiae responsible for Fusarium Head Blight in small-grain cereals. The natural products concentrations effective for reducing or inhibiting the in vitro fungal growth were determined for each fungal species and the following scale of potency was found: cinnamaldehyde > cuminaldehyde > citral > citronellal > bergamot oil > limonene > lemon oil. Moreover, the in vitro mycotoxin productions of the three Fusaria strains exposed to sub-lethal concentrations of the seven products was evaluated. The three fungal species showed variability in response to the treatments, both in terms of inhibition of mycelial growth and in terms of modulation of mycotoxin production that can be enhanced by sub-lethal concentrations of some natural products. This last finding must be taken into account in the frame of an open field application of some plant-derived fungicides.

Effects of radiation on the R/sub 1/ and R/sub 2/ progenies of Pennisetum typhoides S. and H

Energy Technology Data Exchange (ETDEWEB)

Das, L D.V. [Tamil Nadu Agricultural Univ., Coimbatore (India)

1978-05-01

Dry seeds of cumbu strains HB3 and MS7625 were irradiated with different doses of X- and gamma rays. The survival, growth reduction and pollen sterility of R/sub 1/ plants were estimated. The seeds from each R/sub 1/ plant were sown in the field and all clearly deviating plants were scored as morphological mutants. Gamma rays were found to be more effective than X-rays with respect to R/sub 1/ lethality, growth reduction, pollen sterility, and R/sub 2/ mutant frequency. In addition, the survival frequency of the R/sub 1/ plants was reduced to zero per cent when the exposure was increased to 30 and 40 kR of gamma rays. The response of the two strains clearly deviated in X-rays and gamma rays. HB3 showed a lower percentage of lethality, lesser growth reduction and lower pollen sterility. While the relation between R/sub 1/ pollen sterility and the R/sub 2/ mutant frequency was established, it was found that HB3 segregates greater number of mutants than MS7625. The possibility for this might be due to the hybrid parentage of HB3.

Effects of sub-lethal high-pressure homogenization treatment on the outermost cellular structures and the volatile-molecule profiles of two strains of probiotic lactobacilli.

Science.gov (United States)

Tabanelli, Giulia; Vernocchi, Pamela; Patrignani, Francesca; Del Chierico, Federica; Putignani, Lorenza; Vinderola, Gabriel; Reinheimer, Jorge A; Gardini, Fausto; Lanciotti, Rosalba

2015-01-01

Applying sub-lethal levels of high-pressure homogenization (HPH) to lactic acid bacteria has been proposed as a method of enhancing some of their functional properties. Because the principal targets of HPH are the cell-surface structures, the aim of this study was to examine the effect of sub-lethal HPH treatment on the outermost cellular structures and the proteomic profiles of two known probiotic bacterial strains. Moreover, the effect of HPH treatment on the metabolism of probiotic cells within a dairy product during its refrigerated storage was investigated using SPME-GC-MS. Transmission electron microscopy was used to examine the microstructural changes in the outermost cellular structures due to HPH treatment. These alterations may be involved in the changes in some of the technological and functional properties of the strains that were observed after pressure treatment. Moreover, the proteomic profiles of the probiotic strains treated with HPH and incubated at 37°C for various periods showed different peptide patterns compared with those of the untreated cells. In addition, there were differences in the peaks that were observed in the low-mass spectral region (2000-3000 Da) of the spectral profiles of the control and treated samples. Due to pressure treatment, the volatile-molecule profiles of buttermilk inoculated with treated or control cells and stored at 4°C for 30 days exhibited overall changes in the aroma profile and in the production of molecules that improved its sensory profile, although the two different species imparted specific fingerprints to the product. The results of this study will contribute to understanding the changes that occur in the outermost cellular structures and the metabolism of LAB in response to HPH treatment. The findings of this investigation may contribute to elucidating the relationships between these changes and the alterations of the technological and functional properties of LAB induced by pressure treatment.

Late radiation effects in animals surviving lethal irradiation

Energy Technology Data Exchange (ETDEWEB)

Dimitrov, L A

1974-01-01

Animals (rats, mice, dogs) survived lethal irradiation by means of prophylactic-therapeutic treatments or previously irradiated, were studied for late radiation effects: life span, cachexia and fat growing of hypophysical type, tissue or organ hypoplasia manifested by disturbed hemopoiesis, suppressed function of adrenal gland, etc., suppressed immune reactivity of the irradiated organism, atypical biochemical changes in DNA and protein metabolism, epilation, chronic dermatitis, ulcerations, reduced reproductivity or full sterility, damage of kidneys leading to nephrosclerosis, dishormonal states, cataracts, diffuse sclerotic processes, various kinds of malignant and non-malignant tumors. In these cases hemopoiesis compensated for a definite time peripheral blood composition, but during the late period it showed features of incompleteness: shorter life survival of erythrocytes and thrombocytes manifested by a decreased binding of labelled methionine in these blood elements, anemia and relative thrombocytopenia sometimes with an increased number of polychromatic erythrocytes in peripheral blood and a decreased number of reticulocytes at the same time; lymphopenia and relative leucopenia with an increased number of hypersegmented neutrophils. Decreased reproductivity and atypical biochemical changes available in the first generation of the irradiated animals showed the probable role of mutagenic factors in the emergency of some late radiation effects. A significant part of late radiation sequences were due to neuro-endocrine disintegrations. Some of the described late radiation effects were also observed in biological controls as features of ageing. After application of radioprotectors (AET, cysteamine, serotonin) a more marked protective effect is demonstrated in the early reactions (time survival till 30th day, DNA and protein metabolism, immune reactions) of the lethally irradiated animals.

Late radiation effects in animals surviving lethal irradiation

International Nuclear Information System (INIS)

Dimitrov, L.A.

1974-01-01

Animals (rats, mice, dogs) survived lethal irradiation by means of prophylactic-therapeutic treatments or previously irradiated, were studied for late radiation effects: life span, cachexia and fat growing of hypophysical type, tissue or organ hypoplasia manifested by disturbed hemopoiesis, suppressed function of adrenal gland, etc., suppressed immune reactivity of the irradiated organism, atypical biochemical changes in DNA and protein metabolism, epilation, chronic dermatitis, ulcerations, reduced reproductivity or full sterility, damage of kidneys leading to nephrosclerosis, dishormonal states, cataracts, diffuse sclerotic processes, various kinds of malignant and non-malignant tumors. In these cases hemopoiesis compensated for a definite time peripheral blood composition, but during the late period it showed features of incompleteness: shorter life survival of erythrocytes and thrombocytes manifested by a decreased binding of labelled methionine in these blood elements, anemia and relative thrombocytopenia sometimes with an increased number of polychromatic erythrocytes in peripheral blood and a decreased number of reticulocytes at the same time; lymphopenia and relative leucopenia with an increased number of hypersegmented neutrophils. Decreased reproductivity and atypical biochemical changes available in the first generation of the irradiated animals showed the probable role of mutagenic factors in the emergence of some late radiation effects. A significant part of late radiation sequences were due to neuro-endocrine desintegrations which lead to a disturbed supply of the vessels and afterwards to their sclerosis. Some of the described late radiation effects were also observed in biological controls as festures of ageing while in irradiated animals they were manifested in an earlier period. After application of optimal amounts radioprotectors (AET, cysteamine, serotonin) a more marked protective effect is demonstrated in the early reactions (time survival

Exposure to Sub-lethal 2,4-Dichlorophenoxyacetic Acid Arrests Cell Division and Alters Cell Surface Properties in Escherichia coli

Science.gov (United States)

Bhat, Supriya V.; Kamencic, Belma; Körnig, André; Shahina, Zinnat; Dahms, Tanya E. S.

2018-01-01

Escherichia coli is a robust, easily adaptable and culturable bacterium in vitro, and a model bacterium for studying the impact of xenobiotics in the environment. We have used correlative atomic force – laser scanning confocal microscopy (AFM-LSCM) to characterize the mechanisms of cellular response to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). One of the most extensively used herbicides world-wide, 2,4-D is known to cause hazardous effects in diverse non-target organisms. Sub-lethal concentrations of 2,4-D caused DNA damage in E. coli WM1074 during short exposure periods which increased significantly over time. In response to 2,4-D, FtsZ and FtsA relocalized within seconds, coinciding with the complete inhibition of cell septation and cell elongation. Exposure to 2,4-D also resulted in increased activation of the SOS response. Changes to cell division were accompanied by concomitant changes to surface roughness, elasticity and adhesion in a time-dependent manner. This is the first study describing the mechanistic details of 2,4-D at sub-lethal levels in bacteria. Our study suggests that 2,4-D arrests E. coli cell division within seconds after exposure by disrupting the divisome complex, facilitated by dissipation of membrane potential. Over longer exposures, 2,4-D causes filamentation as a result of an SOS response to oxidative stress induced DNA damage. PMID:29472899

Reproductive-phase and interphase lethal cell damage after irradiation and treatment with cytostatics

International Nuclear Information System (INIS)

Hagemann, G.

1979-01-01

After X-ray irradiation of manual cells, two lethal fractions occur due to reproductive and interphase death under low and high radiation doses. The damage kinetics on which this fact is based is compared with hypothetical tumour frequencies and leucemia induction caused in experiments. The reproductive-lethal damage can be manifested by means of colony size spectrometry, with the median colony size class differences (MCD) serving as measure for the damage found. The simultaneous effects of the cytostatics BLEOMYCIN or ICRF 159 and X-rays on reproductive lethal and interphase-lethal damage are measured by means of MCD and survival fraction, and the additive and intensifying effect' is judged with the help of suitably defined terms. This shows that the clinically used ICRF 159 has an additive effect on interphase-lethal and a sub-additive effect on reproductive-lethal cell damage. Thus, favourable results may be expected for the electivity factor in fractionated irradiation and with regard to delayed damage in healthy tissue. (orig.) 891 MG/orig. 892 RDG [de

A novel challenge test incorporating irradiation (60Co) of compost sub-samples to validate thermal lethality towards pathogenic bacteria.

Science.gov (United States)

Moore, John E; Watabe, Miyuki; Stewart, Andrew; Cherie Millar, B; Rao, Juluri R

2009-01-01

Maturing compost heaps normally attaining temperatures ranging from 55 to 65 degrees C is generally regarded to conform to recommended biological risks and sanitation standards for composts stipulated by either EU or US-EPA. Composted products derived from animal sources are further required by EU biohazard safety regulatory legislation that such composts either attain 70 degrees C for over 3h during maturation or via treatment at 70 degrees C for 1h before being considered for dispensation on land. The setting of the upper limit of thermal lethality at 70 degrees C/1h for achieving biosecurity of the animal waste composted products (e.g. pelleted fertilizer formulations) is not properly substantiated by specific validation tests, comprising a 'wipe-out' step (usually via autoclaving) followed by inoculation of a prescribed bacterium, exposure to 70 degrees C/1h and the lethality determined. Pelleted formulations of composts are not amenable for wet methods (autoclaving) for wipe-out sterilization step as this is detrimental to the pellet and compromises sample integrity. This study describes a laboratory method involving the employment of ((60)Co) irradiation 'wipe-out' step to: (a) compost sub-samples drawn from compost formulation heaps and (b) pelleted products derived from composted animal products while determining the thermal lethality of a given time/temperature (70 degrees C/1h) treatment process and by challenging the irradiated sample (not just with one bacterium but), out with 10 potential food-poisoning organisms from the bacterial genera (Campylobacter, Escherichia, Listeria, Salmonella, Yersinia) frequently detected in pig and poultry farm wastes. This challenge test on compost sub-samples can be a useful intervention ploy for 'inspection and validation' technique for composters during the compost maturity process, whose attainment of temperatures of 55-65 degrees C is presumed sufficient for attainment of sanitation. Stringent measures are further

Chloride and sulphate toxicity to Hydropsyche exocellata (Trichoptera, Hydropsychidae): Exploring intraspecific variation and sub-lethal endpoints.

Science.gov (United States)

Sala, Miquel; Faria, Melissa; Sarasúa, Ignacio; Barata, Carlos; Bonada, Núria; Brucet, Sandra; Llenas, Laia; Ponsá, Sergio; Prat, Narcís; Soares, Amadeu M V M; Cañedo-Arguelles, Miguel

2016-10-01

The rivers and streams of the world are becoming saltier due to human activities. In spite of the potential damage that salt pollution can cause on freshwater ecosystems, this is an issue that is currently poorly managed. Here we explored intraspecific differences in the sensitivity of freshwater fauna to two major ions (Cl(-) and SO4(2-)) using the net-spinning caddisfly Hydropsyche exocellata Dufour 1841 (Trichoptera, Hydropsychidae) as a model organism. We exposed H. exocellata to saline solutions (reaching a conductivity of 2.5mScm(-1)) with Cl(-):SO4(2-) ratios similar to those occurring in effluents coming from the meat, mining and paper industries, which release dissolved salts to rivers and streams in Spain. We used two different populations, coming from low and high conductivity streams. To assess toxicity, we measured sub-lethal endpoints: locomotion, symmetry of the food-capturing nets and oxidative stress biomarkers. According to biomarkers and net building, the population historically exposed to lower conductivities (B10) showed higher levels of stress than the population historically exposed to higher conductivities (L102). However, the differences between populations were not strong. For example, net symmetry was lower in the B10 than in the L102 only 48h after treatment was applied, and biomarkers showed a variety of responses, with no discernable pattern. Also, treatment effects were rather weak, i.e. only some endpoints, and in most cases only in the B10 population, showed a significant response to treatment. The lack of consistent differences between populations and treatments could be related to the high salt tolerance of H. exocellata, since both populations were collected from streams with relatively high conductivities. The sub-lethal effects tested in this study can offer an interesting and promising tool to monitor freshwater salinization by combining physiological and behavioural bioindicators. Copyright © 2016 Elsevier B.V. All rights

Lethal and mutagenic effects of fast neutrons of different energy on Streptomyces griseus spores

International Nuclear Information System (INIS)

Podgorskaya, M.E.; Tulina, G.G.; Serdechnaya, A.I.; Matselyukh, B.P.

1986-01-01

A study was made of lethal and mutagenic effects of fast neutrons of different energy on spores of prototrophic and auxotrophic strains of Streptomyces griseus. Relative biological effectiveness of fast neutrons is higher than that of γ-rays and depends on beam energy. Neutrons of 22-50 MeV induce Streptomyces griseus mutations more frequently (by one order of magnitude) than neutrons of 1.4-1.6 MeV do. The obtained mutants can be used in studying Streptomyces griseus genetics

The oxidative potential and biological effects induced by PM{sub 10} obtained in Mexico City and at a receptor site during the MILAGRO Campaign

Energy Technology Data Exchange (ETDEWEB)

Quintana, Raul [Instituto Nacional de Cancerologia, Mexico City (Mexico); Serrano, Jesus [Facultad de Ciencias, Universidad Nacional Autonoma de Mexico, Mexico City (Mexico); Gomez, Virginia [Instituto de Quimica, Universidad Nacional Autonoma de Mexico, Mexico City (Mexico); Foy, Benjamin de [Earth and Atmospheric Sciences, Saint Louis University, St. Louis, MO (United States); Miranda, Javier [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Mexico City (Mexico); Garcia-Cuellar, Claudia [Instituto Nacional de Cancerologia, Mexico City (Mexico); Vega, Elizabeth [Instituto Mexicano del Petroleo, Mexico City (Mexico); Vazquez-Lopez, Ines [Instituto Nacional de Cancerologia, Mexico City (Mexico); Molina, Luisa T. [Molina Center for Energy and the Environment, CA (United States); Massachusetts Institute of Technology, Cambridge, MA (United States); Manzano-Leon, Natalia [Instituto Nacional de Cancerologia, Mexico City (Mexico); Rosas, Irma [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Mexico City (Mexico); Osornio-Vargas, Alvaro R., E-mail: osornio@ualberta.ca [Instituto Nacional de Cancerologia, Mexico City (Mexico); Department of Paediatrics, University of Alberta, 1048 RTF, 8308 114 St, Edmonton, AB T6G 2V2 (Canada)

2011-12-15

As part of a field campaign that studied the impact of Mexico City pollution plume at the local, sub-regional and regional levels, we studied transport-related changes in PM{sub 10} composition, oxidative potential and in vitro toxicological patterns (hemolysis, DNA degradation). We collected PM{sub 10} in Mexico City (T{sub 0}) and at a suburban-receptor site (T{sub 1}), pooled according to two observed ventilation patterns (T{sub 0} {yields} T{sub 1} influence and non-influence). T{sub 0} samples contained more Cu, Zn, and carbon whereas; T{sub 1} samples contained more of Al, Si, P, S, and K (p < 0.05). Only SO{sub 4}{sup -2} increased in T{sub 1} during the influence periods. Oxidative potential correlated with Cu/Zn content (r = 0.74; p < 0.05) but not with biological effects. T{sub 1} PM{sub 10} induced greater hemolysis and T{sub 0} PM{sub 10} induced greater DNA degradation. Influence/non-influence did not affect oxidative potential nor biological effects. Results indicate that ventilation patterns had little effect on intrinsic PM{sub 10} composition and toxicological potential, which suggests a significant involvement of local sources. - Highlights: > Transport-related changes in PM{sub 10} composition, oxidative potential and in vitro toxicity were studied. > Cu, Zn, and carbon levels were predominant in urban PM{sub 10}; receptor site PM{sub 10} was rich in soil elements. > SO{sub 4}{sup -2} was the only component increased in PM{sub 10} from the receptor during the influence periods. > PM{sub 10} oxidative potential correlates with Cu/Zn content but not with studied biological effects. > Ventilation patterns had little effect on PM{sub 10} composition and toxicity. - Mexico City ventilation patterns had little effect on the intrinsic PM{sub 10} composition and toxicological potential, which suggests a significant involvement of local sources as opposed to downwind transport.

Behavioral responses of the estuarine calanoid copepod Eurytemora affinis to sub-lethal concentrations of waterborne pollutants

International Nuclear Information System (INIS)

Michalec, François-Gaël; Holzner, Markus; Menu, Dominique; Hwang, Jiang-Shiou; Souissi, Sami

2013-01-01

Highlights: •We studied the effects of sub-lethal exposure to pollutants on Eurytemora affinis swimming behavior. •Nonylphenol, cadmium and polycyclic aromatic hydrocarbons caused hyperactivity. •Effects were observable within 30 min of exposure and persisted during a depuration period. •The response resembles an escape reaction allowing copepods to evade stressful conditions. -- Abstract: Estuarine waters contain a variety of chemicals which affect to various extents the behavior of aquatic organisms. Little is known, however, on the behavioral response of copepods. The present study shows the results of laboratory experiments investigating the immediate effects of sub-lethal concentrations of three commonly found contaminants on the three-dimensional swimming behavior of the estuarine calanoid copepod Eurytemora affinis. Nonylphenol at 2 μg L −1 , cadmium at 45 ng L −1 and a mixture of low to medium molecular weight polycyclic aromatic hydrocarbons at 40 ng L −1 all affected the swimming behavior of E. affinis adults, increasing both swimming speed and activity. In most cases, effects were observable within 30 min of exposure and persisted or faded during a period of depuration in uncontaminated water of similar duration. In ovigerous females exposed to Cd and PAHs, effects appeared to be more pronounced during the depuration period, suggesting that carrying ovisacs may impair recovery. We quantified differences in the distribution of swimming speed values by considering the relative frequencies of periods of break, slow and fast swimming and we observed a trend toward faster movements in the presence of pollutants. The degree of trajectory complexity, estimated through their fractal dimension, was unaffected by pollutants. Since both narcotic and non-narcotic pollutants induced hyperactivity, our results suggest that changes in behavior after a short-term exposure may be independent of the general mode of action of the chemicals. The increase in

Behavioral responses of the estuarine calanoid copepod Eurytemora affinis to sub-lethal concentrations of waterborne pollutants

Energy Technology Data Exchange (ETDEWEB)

Michalec, François-Gaël [Université Lille Nord de France, F-59000 Lille (France); USTL, LOG, Station Marine de Wimereux, F-62930 Wimereux (France); CNRS, UMR 8187, F-62930 Wimereux (France); National Taiwan Ocean University, Institute of Marine Biology, Keelung, Taiwan, ROC (China); Holzner, Markus [Institute of Environmental Engineering, ETH Zürich (Switzerland); Menu, Dominique [Université Lille Nord de France, F-59000 Lille (France); USTL, LOG, Station Marine de Wimereux, F-62930 Wimereux (France); CNRS, UMR 8187, F-62930 Wimereux (France); Hwang, Jiang-Shiou [National Taiwan Ocean University, Institute of Marine Biology, Keelung, Taiwan, ROC (China); Souissi, Sami, E-mail: sami.souissi@univ-lille1.fr [Université Lille Nord de France, F-59000 Lille (France); USTL, LOG, Station Marine de Wimereux, F-62930 Wimereux (France); CNRS, UMR 8187, F-62930 Wimereux (France)

2013-08-15

Highlights: •We studied the effects of sub-lethal exposure to pollutants on Eurytemora affinis swimming behavior. •Nonylphenol, cadmium and polycyclic aromatic hydrocarbons caused hyperactivity. •Effects were observable within 30 min of exposure and persisted during a depuration period. •The response resembles an escape reaction allowing copepods to evade stressful conditions. -- Abstract: Estuarine waters contain a variety of chemicals which affect to various extents the behavior of aquatic organisms. Little is known, however, on the behavioral response of copepods. The present study shows the results of laboratory experiments investigating the immediate effects of sub-lethal concentrations of three commonly found contaminants on the three-dimensional swimming behavior of the estuarine calanoid copepod Eurytemora affinis. Nonylphenol at 2 μg L{sup −1}, cadmium at 45 ng L{sup −1} and a mixture of low to medium molecular weight polycyclic aromatic hydrocarbons at 40 ng L{sup −1} all affected the swimming behavior of E. affinis adults, increasing both swimming speed and activity. In most cases, effects were observable within 30 min of exposure and persisted or faded during a period of depuration in uncontaminated water of similar duration. In ovigerous females exposed to Cd and PAHs, effects appeared to be more pronounced during the depuration period, suggesting that carrying ovisacs may impair recovery. We quantified differences in the distribution of swimming speed values by considering the relative frequencies of periods of break, slow and fast swimming and we observed a trend toward faster movements in the presence of pollutants. The degree of trajectory complexity, estimated through their fractal dimension, was unaffected by pollutants. Since both narcotic and non-narcotic pollutants induced hyperactivity, our results suggest that changes in behavior after a short-term exposure may be independent of the general mode of action of the chemicals. The

Metabolic responses of Eisenia fetida after sub-lethal exposure to organic contaminants with different toxic modes of action

Energy Technology Data Exchange (ETDEWEB)

McKelvie, Jennifer R.; Wolfe, David M.; Celejewski, Magda A. [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail Toronto, ON M1C 1A4 (Canada); Alaee, Mehran [Environment Canada, 867 Lakeshore Rd., P.O. Box 5050, Burlington, ON L7R 4A6 (Canada); Simpson, Andre J. [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail Toronto, ON M1C 1A4 (Canada); Simpson, Myrna J., E-mail: myrna.simpson@utoronto.ca [Department of Physical and Environmental Sciences, University of Toronto, 1265 Military Trail Toronto, ON M1C 1A4 (Canada)

2011-12-15

Nuclear magnetic resonance (NMR) - based metabolomics has the potential to identify toxic responses of contaminants within a mixture in contaminated soil. This study evaluated the metabolic response of Eisenia fetida after exposure to an array of organic compounds to determine whether contaminant-specific responses could be identified. The compounds investigated in contact tests included: two pesticides (carbaryl and chlorpyrifos), three pharmaceuticals (carbamazephine, estrone and caffeine), two persistent organohalogens (Aroclor 1254 and PBDE 209) and two industrial compounds (nonylphenol and dimethyl phthalate). Control and contaminant-exposed metabolic profiles were distinguished using principal component analysis and potential contaminant-specific biomarkers of exposure were found for several contaminants. These results suggest that NMR-based metabolomics offers considerable promise for differentiating between the different toxic modes of action (MOA) associated with sub-lethal toxicity to earthworms. - Highlights: > NMR-based earthworm metabolomic analysis of the toxic mode of action of various environmental contaminants. > Organic chemicals with different toxic modes of action resulted in varied metabolomic responses for E. fetida. > NMR-based metabolomics differentiates between the different modes of action associated with sub-lethal toxicity. - {sup 1}H NMR metabolomics was used to identify potential biomarkers of organic contaminant exposure in Eisenia fetida earthworms.

Biodiversity of soil bacteria exposed to sub-lethal concentrations of phosphonium-based ionic liquids: Effects of toxicity and biodegradation.

Science.gov (United States)

Sydow, Mateusz; Owsianiak, Mikołaj; Framski, Grzegorz; Woźniak-Karczewska, Marta; Piotrowska-Cyplik, Agnieszka; Ławniczak, Łukasz; Szulc, Alicja; Zgoła-Grześkowiak, Agnieszka; Heipieper, Hermann J; Chrzanowski, Łukasz

2018-01-01

Little is known about the effect of ionic liquids (ILs) on the structure of soil microbial communities and resulting biodiversity. Therefore, we studied the influence of six trihexyl(tetradecyl)phosphonium ILs (with either bromide or various organic anions) at sublethal concentrations on the structure of microbial community present in an urban park soil in 100-day microcosm experiments. The biodiversity decreased in all samples (Shannon's index decreased from 1.75 down to 0.74 and OTU's number decreased from 1399 down to 965) with the largest decrease observed in the microcosms spiked with ILs where biodegradation extent was higher than 80%. (i.e. [P 66614 ][Br] and [P 66614 ][2,4,4]). Despite this general decrease in biodiversity, which can be explained by ecotoxic effect of the ILs, the microbial community in the microcosms was enriched with Gram-negative hydrocarbon-degrading genera e.g. Sphingomonas. It is hypothesized that, in addition to toxicity, the observed decrease in biodiversity and change in the microbial community structure may be explained by the primary biodegradation of the ILs or their metabolites by the mentioned genera, which outcompeted other microorganisms unable to degrade ILs or their metabolites. Thus, the introduction of phosphonium-based ILs into soils at sub-lethal concentrations may result not only in a decrease in biodiversity due to toxic effects, but also in enrichment with ILs-degrading bacteria. Copyright © 2017 Elsevier Inc. All rights reserved.

RBE of Cf-252 neutrons as determined by its lethal, mutagenic, and cytogenetic effects on human cells

International Nuclear Information System (INIS)

Ban, Sadayuki

1989-01-01

To assess the biological effects of neutrons, a man-made spontaneously fissioning isotope, Cf-252, is useful as an experimental model to obtain basic biological data on mixed radiation of gamma-rays and neutrons. The paper describes the lethal effect of Cf-252 radiation on human skin fibroblasts, its lethal and mutagenic effect on HeLa MR cells, and the micronuclei inducing effect on human peripheral lymphocytes. Dose-survival responses of three fibroblast cell strains exposed to Cf-252 radiation are measured. Individual difference is larger than the experimental fluctuation. D 10 values of each strain are obtained from the linear model and linear-quadratic model. Though the dose rate of X-ray is higher than that of Cf-252 radiations, the mean value of RBE(n+γ) is simply obtained as 1.86+0.31 (RBE:relative biological effectiveness). RBE(n) of Cf-252 neutrons to high-dose-rate X-rays is 2.29. After X-ray irradiation, the survival curve of HeLa MR cells gives an extrapolation number of 3.6. It is 1.3 after Cf-252 irradiation. At 50% survival, RBE(n+γ) and RBE(n) are 2.05 and 2.6, respectively. At 10% survival they are 2.05 and 2.6. The mutation frequencies after X-ray irradiation showed a significant non-linear increase with dose. Those after Cf-252 irradiation increase linearly with dose. (N.K.)

Acute, Sub-lethal Cyanide Poisoning in Mice is Ameliorated by Nitrite Alone: Complications Arising from Concomitant Administration of Nitrite and Thiosulfate as an Antidotal Combination

Science.gov (United States)

Cambal, Leah K.; Swanson, Megan R.; Yuan, Quan; Weitz, Andrew C.; Li, Hui-Hua; Pitt, Bruce R.; Pearce, Linda L.; Peterson, Jim

2011-01-01

Sodium nitrite alone is shown to ameliorate sub-lethal cyanide toxicity in mice when given from ~1 hour before until 20 minutes after the toxic dose as demonstrated by the recovery of righting ability. An optimum dose (12 mg/kg) was determined to significantly relieve cyanide toxicity (5.0 mg/kg) when administered to mice intraperitoneally. Nitrite so administered was shown to rapidly produce NO in the bloodsteam as judged by the dose dependent appearance of EPR signals attributable to nitrosylhemoglobin and methemoglobin. It is argued that antagonism of cyanide inhibition of cytochrome c oxidase by NO is the crucial antidotal activity rather than the methemoglobin-forming action of nitrite. Concomitant addition of sodium thiosulfate to nitrite-treated blood resulted in the detection of sulfidomethemoblobin by EPR spectroscopy. Sulfide is a product of thiosulfate hydrolysis and, like cyanide, is known to be a potent inhibitor of cytochrome c oxidase; the effects of the two inhibitors being essentially additive under standard assay conditions, rather than dominated by either one. The findings afford a plausible explanation for an observed detrimental effect in mice associated with the use of the standard nitrite-thiosulfate combination therapy at sub-lethal levels of cyanide intoxication. PMID:21534623

Lethal and sub-lethal evaluation of Indigo Carmine dye and byproducts after TiO2 photocatalysis in the immune system of Eisenia andrei earthworms.

Science.gov (United States)

Genázio Pereira, Patrícia Christina; Reimão, Roberta Valoura; Pavesi, Thelma; Saggioro, Enrico Mendes; Moreira, Josino Costa; Veríssimo Correia, Fábio

2017-09-01

The Indigo carmine (IC) dye has been widely used in textile industries, even though it has been considered toxic for rats, pigs and humans. Owing to its toxicity, wastes containing this compound should be treated to minimize or eliminate their toxic effects on the biota. As an alternative to wastewater treatment, advanced oxidative processes (AOPs) have been highlighted due to their high capacity to destruct organic molecules. In this context, this study aimed to evaluate Indigo Carmine toxicity to soil organisms using the earthworm Eisenia andrei as a model-organism and also verify the efficiency of AOP in reducing its toxicity to these organisms. To this end, lethal (mortality) and sub-lethal (loss or gain of biomass, reproduction, behavior, morphological changes and immune system cells) effects caused by this substance and its degradation products in these annelids were evaluated. Morphological changes were observed even in organisms exposed to low concentrations, while mortality was the major effect observed in individuals exposed to high levels of indigo carmine dye. The organisms exposed to the IC during the contact test showed mortality after 72h of exposure (LC 50 = 75.79mgcm - 2 ), while those exposed to photoproducts showed mortality after 48h (LC 50 = 243min). In the chronic study, the organisms displayed a mortality rate of 14%, while those exposed to the photoproduct reached up to 32.7%. A negative influence of the dye on the reproduction rate was observed, while by-products affected juvenile survival. A loss of viability and alterations in the cellular proportion was verified during the chronic test. However, the compounds did not alter the behavior of the annelids in the leak test (RL ranged from 20% to 30%). Although photocatalysis has been presented as an alternative technology for the treatment of waste containing the indigo carmine dye, this process produced byproducts even more toxic than the original compounds to E. andrei. Copyright © 2017

Linking sub-individual and supra-individual effects in Daphnia magna exposed to sub-lethal concentration of chlorpyrifos.

Science.gov (United States)

Ferrario, Claudia; Parolini, Marco; De Felice, Beatrice; Villa, Sara; Finizio, Antonio

2018-04-01

The main objective of the present study was to investigate possible links between sub-individual and supra-individual levels (i.e. population level) biomarkers in D. magna exposed to sublethal concentrations of the insecticide chlorpyrifos (CPF). To achieve the aim, 8-day old individuals were exposed for 96 h to two environmentally relevant concentrations of CPF (50 and 250 ng/L). Sub-individual level effects were investigated by measuring the activity of antioxidant (SOD, CAT, and GPx) and detoxifying (GST) enzymes, as well as by measuring the acetylcholinesterase (AChE) inhibition. In addition, the effects at supra-individual level were assessed by using a video-tracking system and analyzing changes in swimming capabilities (i.e. percentage of activity time, distance moved, and velocity). Our data have shown that daphnids exposed to both CPF concentrations were in a condition of stress which was highlighted by changes in both sub- and supra-individual biomarkers. Moreover, our results highlighted that the lowest tested CPF concentration did not modulate the antioxidant and detoxifying enzymes, whereas, an inhibition of AChE and a decrease of some parameters related to swimming behaviour (distance moved and velocity) were noted. On the contrary, significant changes in all the sub-individual biomarkers were measured at the highest tested concentration. In addition, organisms recovered the movement capability (distance moved) and also activate a mechanism of avoidance (increased swimming velocity). On the other hand, a reduction in the percent of active time was measured and this was attributed to the energy spent by organisms to activate antioxidant and detoxifying enzymes and the mechanism of avoidance. Based on these results, our study suggests the existence of a link between sub- and supra-individual levels, as the activation or non-activation in the antioxidant and detoxifying enzymes activities can led to different modifications of the swimming behaviour

Effects of sub-lethal levels of dichlorodiphenyltrichloroethane and dichlorodiphenyldichloroethylene on in vitro steroid biosynthesis by ovarian follicles or steroid metabolism by embryos of rainbow trout (Oncorhynchus mykiss)

Energy Technology Data Exchange (ETDEWEB)

Petkam, Rakpong [Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ont., N1G 2W1 (Canada); Renaud, Rick [Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ont., N1G 2W1 (Canada); Lin, Lucy [Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ont., N1G 2W1 (Canada); Boermans, Herman [Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ont., N1G 2W1 (Canada); Leatherland, John [Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ont., N1G 2W1 (Canada)]. E-mail: jleather@ovc.uoguelph.ca

2005-07-01

This study examined the possibility that DDT and DDE, at sub-lethal exposure levels, exert direct effects on the biotransformation of gonadal steroids by rainbow trout (Oncorhynchus mykiss) ovarian follicles and embryos. Ovarian follicles were co-incubated with DDT or DDE at 0.01 or 1 mg l{sup -1} to examine effects of the pesticides on basal or cAMP-activated steroidogenesis. Ovarian preparations were incubated with radiolabelled [{sup 3}H]pregnenolone ([{sup 3}H]P{sub 5}), and the tritiated metabolites of [{sup 3}H]P{sub 5} metabolism were separated using high-performance liquid chromatography (HPLC). Testosterone (T) and 17{beta}-estradiol (E{sub 2}) production were also measured using radioimmunoassay (RIA). Embryos were either exposed to the pesticides in ovo, or co-incubated in vitro with the pesticides. The effect of the pesticides on embryo steroid biotransformation was examined using a range of radioactively labelled substrates, including [{sup 3}H]P{sub 5}, [{sup 3}H]progesterone ([{sup 3}H]P{sub 4}), [{sup 3}H]T and [{sup 3}H]E{sub 2}. At the concentrations used, the pesticides had no significant effect on the relative amounts of unconjugated radiolabelled steroids formed by the biotransformation of [{sup 3}H]P{sub 5} under conditions of basal or cAMP-stimulated ovarian steroidogenesis. However, DDT and DDE appeared to reduce the basal accumulation of androgen as a product of P{sub 5} biotransformation by ovarian follicles. Basal or cAMP-stimulated total estrogen production was not affected. In addition, DDT at 1 mg l{sup -1} and DDE at 0.01 mg l{sup -1} significantly increased and decreased cAMP-stimulated T accumulation, respectively. Also DDT at 0.01 mg l{sup -1} and DDE at 1 mg l{sup -1} significantly increased and decreased basal E{sub 2} accumulation, respectively. The steroid metabolites synthesized from the different substrates by embryos were essentially similar in both controls and pesticide-exposed groups, and the survival of embryos to hatch

Metabolic responses of Eisenia fetida after sub-lethal exposure to organic contaminants with different toxic modes of action

International Nuclear Information System (INIS)

McKelvie, Jennifer R.; Wolfe, David M.; Celejewski, Magda A.; Alaee, Mehran; Simpson, Andre J.; Simpson, Myrna J.

2011-01-01

Nuclear magnetic resonance (NMR) - based metabolomics has the potential to identify toxic responses of contaminants within a mixture in contaminated soil. This study evaluated the metabolic response of Eisenia fetida after exposure to an array of organic compounds to determine whether contaminant-specific responses could be identified. The compounds investigated in contact tests included: two pesticides (carbaryl and chlorpyrifos), three pharmaceuticals (carbamazephine, estrone and caffeine), two persistent organohalogens (Aroclor 1254 and PBDE 209) and two industrial compounds (nonylphenol and dimethyl phthalate). Control and contaminant-exposed metabolic profiles were distinguished using principal component analysis and potential contaminant-specific biomarkers of exposure were found for several contaminants. These results suggest that NMR-based metabolomics offers considerable promise for differentiating between the different toxic modes of action (MOA) associated with sub-lethal toxicity to earthworms. - Highlights: → NMR-based earthworm metabolomic analysis of the toxic mode of action of various environmental contaminants. → Organic chemicals with different toxic modes of action resulted in varied metabolomic responses for E. fetida. → NMR-based metabolomics differentiates between the different modes of action associated with sub-lethal toxicity. - 1 H NMR metabolomics was used to identify potential biomarkers of organic contaminant exposure in Eisenia fetida earthworms.

Making sense of nickel accumulation and sub-lethal toxic effects in saline waters: Fate and effects of nickel in the green crab, Carcinus maenas.

Science.gov (United States)

Blewett, Tamzin A; Glover, Chris N; Fehsenfeld, Sandra; Lawrence, Michael J; Niyogi, Som; Goss, Greg G; Wood, Chris M

2015-07-01

In freshwater, invertebrates nickel (Ni) is considered an ionoregulatory toxicant, but its mechanism of toxicity in marine settings, and how this varies with salinity, is poorly understood. This study investigated Ni accumulation and physiological mechanisms of sub-lethal Ni toxicity in the euryhaline green crab Carcinus maenas. Male crabs were exposed to 8.2μg/L (the US EPA chronic criterion concentration for salt waters) of waterborne Ni (radiolabelled with (63)Ni) at three different salinities, 20%, 60% and 100% SW for 24h. Whole body Ni accumulation in 20% SW was 3-5 fold greater than in 60% or 100% SW, and >80% of accumulated Ni was in the carapace at all salinities. Ni also accumulated in posterior gill 8, which showed a higher accumulation in 20% SW than in other salinities, a pattern also seen at higher exposure concentrations of Ni (500 and 3000μg/L). Gill perfusion experiments revealed that Ni was taken up by both anterior and posterior gills, but in 20% SW the posterior gill 8, which performs ionoregulatory functions, accumulated more Ni than the anterior gill 5, which primarily has a respiratory function. The sub-lethal consequences of Ni exposure were investigated by placing crabs in Ni concentrations of 8.2, 500, and 3000μg/L at 20, 60 or 100% SW for 24h. In 20% SW, haemolymph Ca levels were significantly decreased by exposure to Ni concentrations of 8.2μg/L or higher, whereas Na concentrations were depressed only at 3000μg/L. Na(+)/K(+)-ATPase activity was inhibited at both 500 and 3000μg/L in gill 8, but only in 20% SW. Haemolymph K, Mg, and osmolality were unaffected throughout, though all varied with salinity in the expected fashion. These data suggest that Ni impacts ionoregulatory function in the green crab, in a gill- and salinity-dependent manner. Copyright © 2015 Elsevier B.V. All rights reserved.

Lethal and sublethal effects of methoxyphenozide on the development, survival and reproduction of the fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

Energy Technology Data Exchange (ETDEWEB)

Zarate, N.; Diaz, O. [Universidad Autonoma de San Luis Potosi (Mexico). Facultad de Agronomia; Martinez, A.M.; Figueroa, J.I.; Pineda, S., E-mail: spineda_us@yahoo.co [Universidad Michoacana de San Nicolas de Hidalgo, Tarimbaro, Michoacan (Mexico). Inst. de Investigaciones Agropecuarias y Forestales; Schneider, M.I. [National Council of Scientific and Technical Research (CEPAVE/CCT/CONICET), La Plata (Argentina). Centro de Estudios Parasitologicos y de Vectores. Centro Cientifico Tecnologico; Smagghe, G. [Ghent University, Ghent (Belgium). Faculty of Bioscience Engineering. Lab of Agrozoology; Vinuela, E.; Budia, F. [Escuela Tecnica Superior de Ingenieros Agronomos, Madrid (Spain). Escuela Tecnica Superior de Ingenieros Agronomos. Proteccion de Cultivos

2011-01-15

The lethal and sublethal effects of the ecdysone agonist methoxyphenozide on the fall armyworm, Spodoptera frugiperda (J. E. Smith), were investigated by feeding a methoxyphenozide-treated diet to fifth instars until pupation in doses corresponding to the LC{sub 10} and LC{sub 25} for the compound. Larval mortality reached 8% and 26% in the low and high concentration groups, respectively, on the seventh day of the experiment. A progressive larval mortality of 12% for the LC{sub 10} and 60% for the LC{sub 25} was observed before pupation. Treated larvae exhibited lower pupal weights, higher pupal mortality, presence of deformed pupae, and more deformed adults than untreated larvae. The incorporation of methoxyfenozide into the diet had a significant effect on the timing of larval development. The development period for males and females was about seven days longer than the controls for both concentrations tested. In contrast, the compound affected neither pupae nor adult longevity. Finally, S. frugiperda adults that resulted from fifth instars treated with methoxyfenozide were not affected in their mean cumulative number of eggs laid per female (fecundity), nor percentages of eggs hatched (fertility), or the sex ratio. Our results suggest that the combination of lethal and sublethal effects of methoxyfenozide may have important implications for the population dynamics of the fall armyworm. (author)

RpoS plays a central role in the SOS induction by sub-lethal aminoglycoside concentrations in Vibrio cholerae.

Science.gov (United States)

Baharoglu, Zeynep; Krin, Evelyne; Mazel, Didier

2013-01-01

Bacteria encounter sub-inhibitory concentrations of antibiotics in various niches, where these low doses play a key role for antibiotic resistance selection. However, the physiological effects of these sub-lethal concentrations and their observed connection to the cellular mechanisms generating genetic diversification are still poorly understood. It is known that, unlike for the model bacterium Escherichia coli, sub-minimal inhibitory concentrations (sub-MIC) of aminoglycosides (AGs) induce the SOS response in Vibrio cholerae. SOS is induced upon DNA damage, and since AGs do not directly target DNA, we addressed two issues in this study: how sub-MIC AGs induce SOS in V. cholerae and why they do not do so in E. coli. We found that when bacteria are grown with tobramycin at a concentration 100-fold below the MIC, intracellular reactive oxygen species strongly increase in V. cholerae but not in E. coli. Using flow cytometry and gfp fusions with the SOS regulated promoter of intIA, we followed AG-dependent SOS induction. Testing the different mutation repair pathways, we found that over-expression of the base excision repair (BER) pathway protein MutY relieved this SOS induction in V. cholerae, suggesting a role for oxidized guanine in AG-mediated indirect DNA damage. As a corollary, we established that a BER pathway deficient E. coli strain induces SOS in response to sub-MIC AGs. We finally demonstrate that the RpoS general stress regulator prevents oxidative stress-mediated DNA damage formation in E. coli. We further show that AG-mediated SOS induction is conserved among the distantly related Gram negative pathogens Klebsiella pneumoniae and Photorhabdus luminescens, suggesting that E. coli is more of an exception than a paradigm for the physiological response to antibiotics sub-MIC.

Proteomic analysis of differentiating neuroblastoma cells treated with sub-lethal neurite inhibitory concentrations of diazinon: Identification of novel biomarkers of effect

International Nuclear Information System (INIS)

Harris, W.; Sachana, M.; Flaskos, J.; Hargreaves, A.J.

2009-01-01

In previous work we showed that sub-lethal levels of diazinon inhibited neurite outgrowth in differentiating N2a neuroblastoma cells. Western blotting analysis targeted at proteins involved in axon growth and stress responses, revealed that such exposure led to a reduction in the levels of neurofilament heavy chain, microtubule associated protein 1 B (MAP 1B) and HSP-70. The aim of this study was to apply the approach of 2 dimensional polyacrylamide gel electrophoresis and mass spectrometry to identify novel biomarkers of effect. A number of proteins were found to be up-regulated compared to the control on silver-stained gels. These were classified in to 3 main groups of proteins: cytosolic factors, chaperones and the actin-binding protein cofilin, all of which are involved in cell differentiation, survival or metabolism. The changes observed for cofilin were further confirmed by quantitative Western blotting analysis with anti-actin and anti-cofilin antibodies. Indirect immunofluorescence staining with the same antibodies indicated that the microfilament network was disrupted in diazinon-treated cells. Our data suggest that microfilament organisation is disrupted by diazinon exposure, which may be related to increased cofilin expression.

{sup 1}H NMR-based metabolomics of time-dependent responses of Eisenia fetida to sub-lethal phenanthrene exposure

Energy Technology Data Exchange (ETDEWEB)

Lankadurai, Brian P.; Wolfe, David M.; Simpson, Andre J. [Department of Chemistry, University of Toronto, 1265 Military Trail, Toronto, Ontario M1C 1A4 Canada (Canada); Simpson, Myrna J., E-mail: myrna.simpson@utoronto.ca [Department of Chemistry, University of Toronto, 1265 Military Trail, Toronto, Ontario M1C 1A4 Canada (Canada)

2011-10-15

{sup 1}H NMR-based metabolomics was used to examine the response of the earthworm Eisenia fetida after exposure to sub-lethal concentrations of phenanthrene over time. Earthworms were exposed to 0.025 mg/cm{sup 2} of phenanthrene (1/64th of the LC{sub 50}) via contact tests over four days. Earthworm tissues were extracted using a mixture of chloroform, methanol and water, resulting in polar and non-polar fractions that were analyzed by {sup 1}H NMR after one, two, three and four days. NMR-based metabolomic analyses revealed heightened E. fetida responses with longer phenanthrene exposure times. Amino acids alanine and glutamate, the sugar maltose, the lipids cholesterol and phosphatidylcholine emerged as potential indicators of phenanthrene exposure. The conversion of succinate to fumarate in the Krebs cycle was also interrupted by phenanthrene. Therefore, this study shows that NMR-based metabolomics is a powerful tool for elucidating time-dependent relationships in addition to the mode of toxicity of phenanthrene in earthworm exposure studies. - Highlights: > NMR-based earthworm metabolomic analysis of the mode of action of phenanthrene is presented. > The earthworm species E. fetida were exposed to sub-lethal phenanthrene concentrations. > Both polar and non-polar metabolites of E. fetida tissue extracts were analyzed by {sup 1}H NMR. > Longer phenanthrene exposure times resulted in heightened earthworm responses. > An interruption of the Krebs cycle was also observed due to phenanthrene exposure. - {sup 1}H NMR metabolomics is used to determine the relationship between phenanthrene exposure and the metabolic response of the earthworm E. fetida over time and also to elucidate the phenanthrene mode of toxicity.

Stress response of the black coral Leiopathes glaberrima when exposed to sub-lethal amounts of crude oil and dispersant

Directory of Open Access Journals (Sweden)

Dannise V. Ruiz-Ramos

2017-12-01

Full Text Available The 2010 Deep Water Horizon oil well failure released billions of gallons of crude oil into the deep Gulf of Mexico, and, combined with chemical dispersants, this oil caused significant coral mortality. However, the mechanisms by which oil and dispersed oil impact deep marine fauna are not well understood. Here, we investigate the effects of oil and dispersed oil on a black coral common in the deep Gulf of Mexico, 'Leiopathes glaberrima. 'This coral occurs in several color morphs that show ecological and genetic differences. We hypothesized that dispersed oil would be more detrimental to coral health than oil alone and that this difference would be detectable in the gene expression response of the colonies even at sub-lethal concentrations. In two experiments, four and six colonies of red and white color morphs were exposed to oil, dispersant, and dispersed oil for a minimum of 96 hours. Visual assessment indicated that indeed dispersant and dispersed oil treatments were more damaging than oil alone, for target concentrations of 25 mg L–1. Decline in health was observed for all treatments, independently of color morphotype, but the decline was faster in the white colonies exposed to dispersant. The responses to the treatments were also investigated by monitoring gene expression after 24 hours of sub-lethal chemical exposure. Coral gene expression differed by chemical stressor. Interestingly, the polycyclic aromatic hydrocarbon biomarker gene, cytochrome P450, was only up-regulated in dispersed oil but not oil alone, suggesting that the dispersant increased the availability of such hydrocarbons in the tissue. The gene expression response was apparent at 24 hours when visual impacts were not (yet detectable. The use of chemical dispersants in oil-spill remediation may cause health declines in deep-water corals and deserves further study.

Investigation of toxic effects of imidazolium ionic liquids, [bmim][BF{sub 4}] and [omim][BF{sub 4}], on marine mussel Mytilus galloprovincialis with or without the presence of conventional solvents, such as acetone

Energy Technology Data Exchange (ETDEWEB)

Tsarpali, Vasiliki; Belavgeni, Alexia; Dailianis, Stefanos, E-mail: sdailianis@upatras.gr

2015-07-15

Highlights: • The toxic effects of [bmim][BF{sub 4}] and [omim][BF{sub 4}] on mussels were investigated. • Both ILs could induce lethal and nonlethal effects on Mytilus galloprovincialis. • Different extent of IL-mediated adverse effects was observed in mussel hemocytes. • The alkyl chain length and lipophilicity of ILs are crucial for their toxicity. • Acetone influences the oxidative and genotoxic effects of [omim][BF{sub 4}]. - Abstract: This study investigated the cytotoxic, oxidative and genotoxic effects of two commonly used imidazolium ionic liquids (ILs), [bmim][BF{sub 4}] (1-butyl-3-methylimidazolium) and [omim][BF{sub 4}] (1-methyl-3-octylimidazolium tetrafluoroborate), on the marine mussel Mytilus galloprovincialis, as well as whether acetone could mediate their toxic profile. In this context, mussels were firstly exposed to different concentrations of [bmim][BF{sub 4}] or [omim][BF{sub 4}], with or without the presence of acetone (at a final concentration of 0.06% v/v), for a period of 96 h, in order to determine the concentration that causes 50% mussel mortality (LC{sub 50} values) in each case. Thereafter, mussels were exposed to sub- and non-lethal concentrations of ILs for investigating their ability to cause lysosomal membrane impairment (with the use of neutral red retention assay/NRRT), superoxide anion and lipid peroxidation byproduct (malondialdehyde/MDA) formation, as well as DNA damage and formation of nuclear abnormalities in hemocytes. The results showed that [omim][BF{sub 4}] was more toxic than [bmim][BF{sub 4}] in all cases, while the presence of acetone resulted in a slight attenuation of its toxicity. The different toxic behavior of ILs was further revealed by the significantly lower levels of NRRT values observed in [omim][BF{sub 4}]-treated mussels, compared to those occurring in [bmim][BF{sub 4}] in all cases. Similarly, [bmim][BF{sub 4}]-mediated oxidative and genotoxic effects were observed only in the highest

Induction of high tolerance to artemisinin by sub-lethal administration: A new in vitro model of P. falciparum.

Directory of Open Access Journals (Sweden)

Serena De Lucia

Full Text Available Artemisinin resistance is a major threat to malaria control efforts. Resistance is characterized by an increase in the Plasmodium falciparum parasite clearance half-life following treatment with artemisinin-based combination therapies (ACTs and an increase in the percentage of surviving parasites. The remarkably short blood half-life of artemisinin derivatives may contribute to drug-resistance, possibly through factors including sub-lethal plasma concentrations and inadequate exposure. Here we selected for a new strain of artemisinin resistant parasites, termed the artemisinin resistant strain 1 (ARS1, by treating P. falciparum Palo Alto (PA cultures with sub-lethal concentrations of dihydroartemisinin (DHA. The resistance phenotype was maintained for over 1 year through monthly maintenance treatments with low doses of 2.5 nM DHA. There was a moderate increase in the DHA IC50 in ARS1 when compared with parental strain PA after 72 h of drug exposure (from 0.68 nM to 2 nM DHA. In addition, ARS1 survived treatment physiologically relevant DHA concentrations (700 nM observed in patients. Furthermore, we confirmed a lack of cross-resistance against a panel of antimalarials commonly used as partner drugs in ACTs. Finally, ARS1 did not contain Pfk13 propeller domain mutations associated with ART resistance in the Greater Mekong Region. With a stable growth rate, ARS1 represents a valuable tool for the development of new antimalarial compounds and studies to further elucidate the mechanisms of ART resistance.

Biological effects induced by K photo-ionisation in and near constituent atoms of DNA

International Nuclear Information System (INIS)

Touati, A.; Herve du Penhoot, M.A.; Fayard, B.; Champion, C.; Abel, F.; Gobert, F.; Lamoureux, M.; Politis, M.F.; Martins, L.; Ricoul, M.; Sabatier, L.; Sage, E.; Chetioui, A.

2002-01-01

In order to assess the lethal efficiency and other biological effects of inner shell ionisations of constituent atoms of DNA ('K' events), experiments were developed at the LURE synchrotron facility using ultrasoft X rays as a probe of K events. The lethal efficiency of ultrasoft X rays above the carbon K threshold was especially investigated using V79 cells and compared with their efficiency to induce double strand breaks in dry plasmid-DNA. A correlation between the K event efficiencies for these processes is shown. Beams of 340 eV were found to be twice as efficient at killing cells than were beams at 250 eV. In addition, a rough two-fold increase of the relative biological effectiveness for dicentric+ring induction has also been observed between 250 and 340 eV radiations. (author)

Effective lethal mutagenesis of influenza virus by three nucleoside analogs.

Science.gov (United States)

Pauly, Matthew D; Lauring, Adam S

2015-04-01

Lethal mutagenesis is a broad-spectrum antiviral strategy that exploits the high mutation rate and low mutational tolerance of many RNA viruses. This approach uses mutagenic drugs to increase viral mutation rates and burden viral populations with mutations that reduce the number of infectious progeny. We investigated the effectiveness of lethal mutagenesis as a strategy against influenza virus using three nucleoside analogs, ribavirin, 5-azacytidine, and 5-fluorouracil. All three drugs were active against a panel of seasonal H3N2 and laboratory-adapted H1N1 strains. We found that each drug increased the frequency of mutations in influenza virus populations and decreased the virus' specific infectivity, indicating a mutagenic mode of action. We were able to drive viral populations to extinction by passaging influenza virus in the presence of each drug, indicating that complete lethal mutagenesis of influenza virus populations can be achieved when a sufficient mutational burden is applied. Population-wide resistance to these mutagenic agents did not arise after serial passage of influenza virus populations in sublethal concentrations of drug. Sequencing of these drug-passaged viral populations revealed genome-wide accumulation of mutations at low frequency. The replicative capacity of drug-passaged populations was reduced at higher multiplicities of infection, suggesting the presence of defective interfering particles and a possible barrier to the evolution of resistance. Together, our data suggest that lethal mutagenesis may be a particularly effective therapeutic approach with a high genetic barrier to resistance for influenza virus. Influenza virus is an RNA virus that causes significant morbidity and mortality during annual epidemics. Novel therapies for RNA viruses are needed due to the ease with which these viruses evolve resistance to existing therapeutics. Lethal mutagenesis is a broad-spectrum strategy that exploits the high mutation rate and the low

Relative biological efficiency of 592 MeV protons. Analysis of the biological effect of secondary radiation

International Nuclear Information System (INIS)

Legeay, G.; Baarli, J.

1968-01-01

The relative biological efficiency (RBE) of high energy protons is of importance because of their effects in the field of radioprotection around large accelerators and during space-flights. The nature of the interactions between 592 MeV protons and biological tissues makes it necessary to take into consideration the contribution of secondary radiation to the biological effect. Since it is not possible to obtain from a synchrotron a beam having a sufficiently large cross-section to irradiate large animals, one has to resort to certain devices concerning the mode of exposure when small laboratory animals are used. By irradiating rats individually and in groups, and by using the lethal test as a function of time, the authors show that the value of the RBE is different for animals of the same species having the same biological parameters. Thus there appears an increase in the biological effect due to secondary radiation produced in nuclear cascades which develop in a large volume, for example that of a human being. (author) [fr

The Effects of Anthrax Lethal Toxin on Host Barrier Function

Directory of Open Access Journals (Sweden)

David M. Frucht

2011-06-01

Full Text Available The pathological actions of anthrax toxin require the activities of its edema factor (EF and lethal factor (LF enzyme components, which gain intracellular access via its receptor-binding component, protective antigen (PA. LF is a metalloproteinase with specificity for selected mitogen-activated protein kinase kinases (MKKs, but its activity is not directly lethal to many types of primary and transformed cells in vitro. Nevertheless, in vivo treatment of several animal species with the combination of LF and PA (termed lethal toxin or LT leads to morbidity and mortality, suggesting that LT-dependent toxicity is mediated by cellular interactions between host cells. Decades of research have revealed that a central hallmark of this toxicity is the disruption of key cellular barriers required to maintain homeostasis. This review will focus on the current understanding of the effects of LT on barrier function, highlighting recent progress in establishing the molecular mechanisms underlying these effects.

Effect of ionizing radiation on chemical and biological properties of Salmonella minnesota R595 lipopolysaccharide

Energy Technology Data Exchange (ETDEWEB)

El Sabbagh, M; Galanos, C; Luederitz, O [Max-Planck-Institut fuer Immunbiologie, Freiburg (Germany, F.R.); Bertok, L [Orszagos Frederic Joliot-Curie Sugarbiologiai es Sugaregeszseguegyi Kutato Intezet, Budapest (Hungary); Fuest, Gy [Orszagos Haema--tologiai es Vertranszfuzios Intezet, Budapest (Hungary)

1982-01-01

The effects of /sup 60/Co irradiation performed with various doses on the biological and chemical properties of the endotoxin of the Salmonella minnesota R595 were compared with those of unirradiated ones. The biological activity was measured using the lethal toxicity test, the local Schwartzman reaction and by activating the complementary system. Increasing the irradiation dose from 50 to 200 kGy the preparation became less active in the biological tests but the protective activity against the lethal action of the endotoxin remained uneffected. The irradiation resulted in a dose-dependent decrease of the amounts of 2-keto-3-deoxy-octonate, glucosamine, fatty acids, but did not affect all the degradation products identified. Therefore, no correlation between the chemical composition and the absence of endotoxin activity was found.

1H NMR-based metabolomics of time-dependent responses of Eisenia fetida to sub-lethal phenanthrene exposure

International Nuclear Information System (INIS)

Lankadurai, Brian P.; Wolfe, David M.; Simpson, Andre J.; Simpson, Myrna J.

2011-01-01

1 H NMR-based metabolomics was used to examine the response of the earthworm Eisenia fetida after exposure to sub-lethal concentrations of phenanthrene over time. Earthworms were exposed to 0.025 mg/cm 2 of phenanthrene (1/64th of the LC 50 ) via contact tests over four days. Earthworm tissues were extracted using a mixture of chloroform, methanol and water, resulting in polar and non-polar fractions that were analyzed by 1 H NMR after one, two, three and four days. NMR-based metabolomic analyses revealed heightened E. fetida responses with longer phenanthrene exposure times. Amino acids alanine and glutamate, the sugar maltose, the lipids cholesterol and phosphatidylcholine emerged as potential indicators of phenanthrene exposure. The conversion of succinate to fumarate in the Krebs cycle was also interrupted by phenanthrene. Therefore, this study shows that NMR-based metabolomics is a powerful tool for elucidating time-dependent relationships in addition to the mode of toxicity of phenanthrene in earthworm exposure studies. - Highlights: → NMR-based earthworm metabolomic analysis of the mode of action of phenanthrene is presented. → The earthworm species E. fetida were exposed to sub-lethal phenanthrene concentrations. → Both polar and non-polar metabolites of E. fetida tissue extracts were analyzed by 1 H NMR. → Longer phenanthrene exposure times resulted in heightened earthworm responses. → An interruption of the Krebs cycle was also observed due to phenanthrene exposure. - 1 H NMR metabolomics is used to determine the relationship between phenanthrene exposure and the metabolic response of the earthworm E. fetida over time and also to elucidate the phenanthrene mode of toxicity.

Indirect effects of non-lethal predation on bivalve activity and sediment reworking

NARCIS (Netherlands)

Maire, O.; Merchant, J.N.; Bulling, M.; Teal, L.R.; Gremare, A.; Duchene, J.C.; Solan, M.

2010-01-01

Deposit-feeders are the dominant bioturbators of aquatic sediments, where they profoundly impact biogeochemical processes, but they are also vulnerable to both lethal and non-lethal predation by a large variety of predators. In this study, we performed a series of experiments to test the effects of

Effect of lethality on the extinction and on the error threshold of quasispecies.

Science.gov (United States)

Tejero, Hector; Marín, Arturo; Montero, Francisco

2010-02-21

In this paper the effect of lethality on error threshold and extinction has been studied in a population of error-prone self-replicating molecules. For given lethality and a simple fitness landscape, three dynamic regimes can be obtained: quasispecies, error catastrophe, and extinction. Using a simple model in which molecules are classified as master, lethal and non-lethal mutants, it is possible to obtain the mutation rates of the transitions between the three regimes analytically. The numerical resolution of the extended model, in which molecules are classified depending on their Hamming distance to the master sequence, confirms the results obtained in the simple model and shows how an error catastrophe regime changes when lethality is taken in account. (c) 2009 Elsevier Ltd. All rights reserved.

Immunotherapy with mutated onchocystatin fails to enhance the efficacy of a sub-lethal oxytetracycline regimen against Onchocerca ochengi.

Science.gov (United States)

Bah, Germanus S; Tanya, Vincent N; Makepeace, Benjamin L

2015-08-15

Human onchocerciasis (river blindness), caused by the filarial nematode Onchocerca volvulus, has been successfully controlled by a single drug, ivermectin, for over 25 years. Ivermectin prevents the disease symptoms of severe itching and visual impairment by killing the microfilarial stage, but does not eliminate the adult parasites, necessitating repeated annual treatments. Mass drug administration with ivermectin does not always break transmission in forest zones and is contraindicated in individuals heavily co-infected with Loa loa, while reports of reduced drug efficacy in Ghana and Cameroon may signal the development of resistance. An alternative treatment for onchocerciasis involves targeting the essential Wolbachia symbiont with tetracycline or its derivatives, which are adulticidal. However, implementation of antibiotic therapy has not occurred on a wide scale due to the prolonged treatment regimen required (several weeks). In the bovine Onchocerca ochengi system, it has been shown previously that prolonged oxytetracycline therapy increases eosinophil counts in intradermal nodules, which kill the adult worms by degranulating on their surface. Here, in an "immunochemotherapeutic" approach, we sought to enhance the efficacy of a short, sub-lethal antibiotic regimen against O. ochengi by prior immunotherapy targeting onchocystatin, an immunomodulatory protein located in the adult female worm cuticle. A key asparagine residue in onchocystatin was mutated to ablate immunomodulatory activity, which has been demonstrated previously to markedly improve the protective efficacy of this vaccine candidate when used as an immunoprophylactic. The immunochemotherapeutic regimen was compared with sub-lethal oxytetracycline therapy alone; onchocystatin immunotherapy alone; a gold-standard prolonged, intermittent oxytetracycline regimen; and no treatment (negative control) in naturally infected Cameroonian cattle. Readouts were collected over one year and comprised adult

Highly Resolved Sub-Terahertz Vibrational Spectroscopy of Biological Macromolecules and Bacteria Cells

Science.gov (United States)

2016-07-01

HIGHLY RESOLVED SUB-TERAHERTZ VIBRATIONAL SPECTROSCOPY OF BIOLOGICAL MACROMOLECULES AND BACTERIA CELLS ECBC...SUBTITLE Highly Resolved Sub-Terahertz Vibrational Spectroscopy of Biological Macromolecules and Bacteria Cells 5a. CONTRACT NUMBER W911SR-14-P...22 4.3 Bacteria THz Study

Toxicological aspects of photocatalytic degradation of selected xenobiotics with nano-sized Mn-doped TiO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Ozmen, Murat, E-mail: murat.ozmen@inonu.edu.tr [Inonu University, Faculty of Science, Department of Biology, Malatya (Turkey); Güngördü, Abbas [Inonu University, Faculty of Science, Department of Biology, Malatya (Turkey); Erdemoglu, Sema [Inonu University, Faculty of Science, Department of Chemistry, Malatya (Turkey); Ozmen, Nesrin [Inonu University, Faculty of Education, Department of Science Teaching Program, Malatya (Turkey); Asilturk, Meltem [Akdeniz University, Department of Materials Science and Engineering, Antalya (Turkey)

2015-08-15

Highlights: • Undoped and Mn-doped TiO{sub 2} nanoparticles were synthesized and characterized. • The photocatalytic efficiency of the photocatalysts was evaluated for BPA and ATZ. • Toxicity of photocatalysts and photocatalytic by-products were determined. • Mn-doped TiO{sub 2} nanoparticles did not cause significant lethality on X. laevis. • Degradation of BPA caused a significant reduction of lethal effects. - Abstract: The toxic effects of two selected xenobiotics, bisphenol A (BPA) and atrazine (ATZ), were evaluated after photocatalytic degradation using nano-sized, Mn-doped TiO{sub 2}. Undoped and Mn-doped TiO{sub 2} nanoparticles were synthesized. The samples were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), UV–vis-diffuse reflectance spectra (DRS), X-ray fluorescence spectroscopy (XRF), and BET surface area. The photocatalytic efficiency of the undoped and Mn-doped TiO{sub 2} was evaluated for BPA and ATZ. The toxicity of the synthesized photocatalysts and photocatalytic by-products of BPA and ATZ was determined using frog embryos and tadpoles, zebrafish embryos, and bioluminescent bacteria. Possible toxic effects were also evaluated using selected enzyme biomarkers. The results showed that Mn-doped TiO{sub 2} nanoparticles did not cause significant lethality in Xenopus laevis embryos and tadpoles, but nonfiltered samples caused lethality in zebrafish. Furthermore, Mn-doping of TiO{sub 2} increased the photocatalytic degradation capability of nanoparticles, and it successfully degraded BPA and AZT, but degradation of AZT caused an increase of the lethal effects on both tadpoles and fish embryos. Degradation of BPA caused a significant reduction of lethal effects, especially after 2–4 h of degradation. However, biochemical assays showed that both Mn-doped TiO{sub 2} and the degradation by-products caused a significant change of selected biomarkers on X. laevis tadpoles; thus, the ecological risks of Mn

Theories of Lethal Mutagenesis: From Error Catastrophe to Lethal Defection.

Science.gov (United States)

Tejero, Héctor; Montero, Francisco; Nuño, Juan Carlos

2016-01-01

RNA viruses get extinct in a process called lethal mutagenesis when subjected to an increase in their mutation rate, for instance, by the action of mutagenic drugs. Several approaches have been proposed to understand this phenomenon. The extinction of RNA viruses by increased mutational pressure was inspired by the concept of the error threshold. The now classic quasispecies model predicts the existence of a limit to the mutation rate beyond which the genetic information of the wild type could not be efficiently transmitted to the next generation. This limit was called the error threshold, and for mutation rates larger than this threshold, the quasispecies was said to enter into error catastrophe. This transition has been assumed to foster the extinction of the whole population. Alternative explanations of lethal mutagenesis have been proposed recently. In the first place, a distinction is made between the error threshold and the extinction threshold, the mutation rate beyond which a population gets extinct. Extinction is explained from the effect the mutation rate has, throughout the mutational load, on the reproductive ability of the whole population. Secondly, lethal defection takes also into account the effect of interactions within mutant spectra, which have been shown to be determinant for the understanding the extinction of RNA virus due to an augmented mutational pressure. Nonetheless, some relevant issues concerning lethal mutagenesis are not completely understood yet, as so survival of the flattest, i.e. the development of resistance to lethal mutagenesis by evolving towards mutationally more robust regions of sequence space, or sublethal mutagenesis, i.e., the increase of the mutation rate below the extinction threshold which may boost the adaptability of RNA virus, increasing their ability to develop resistance to drugs (including mutagens). A better design of antiviral therapies will still require an improvement of our knowledge about lethal

Determination of gamma radiation lethal dose (LD{sub 50}) and resveratrol cytotoxicity level in tumor cells line

Energy Technology Data Exchange (ETDEWEB)

Magalhaes, Vanessa D.; Rogero, Sizue O.; Rogero, Jose R. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Cruz, Aurea S. [Instituto Adolfo Lutz (IAL-SP) Secao de Culturas Celulares, SP (Brazil)

2011-07-01

Cancer is a disease with high incidence and it is considered a worldwide public health problem. Resveratrol is a polyphenol occurring naturally in a wide variety of plants according to response of ultraviolet radiation (UV) exposition or according to mechanical stress resulting of pathogens or chemical and physical agents. This polyphenol possesses a pharmacological activity of carcinogenesis inhibition in multiple levels. It also protects cells by scavenging the free radicals which are considered toxic products. These free radicals are formed of natural process of cell aging and also by incidence of ionizing radiation in the organism. Thus, resveratrol is considered as a cell radioprotector. On the other hand, in some elevated concentrations resveratrol may be considered as a radiosensitizing. The aim of this work was the determination of radiation lethal dose (LD{sub 50}) and also verifies the cytotoxicity level of resveratrol in tumor cells line: muco epidermoid pulmonary carcinoma cells (NCI-H292) and rhabdomyosarcoma cells (RD). The cytotoxicity test was performed by neutral red uptake assay. The results of resveratrol IC{sub 50%} in NCI-H292 cells was 192{mu}M and in RD cells was 128{mu}M; and RD cells gamma radiation LD{sub 50} was 435Gy. (author)

Conflict Without Casualties: Non-Lethal Weapons in Irregular Warfare

Science.gov (United States)

2007-09-01

the body,” and the Geneva Protocol of 1925, bans the use of chemical and biological weapons .11 On 8 April 1975, President Ford issued Executive...E Funding – PE 63851M) (accessed 15 December 2006). The American Journal of Bioethics . “Medical Ethics and Non-Lethal Weapons .” Bioethics.net...CASUALTIES: NON-LETHAL WEAPONS IN IRREGULAR WARFARE by Richard L. Scott September 2007 Thesis Advisor: Robert McNab Second Reader

Variability in mutational fitness effects prevents full lethal transitions in large quasispecies populations

Science.gov (United States)

Sardanyés, Josep; Simó, Carles; Martínez, Regina; Solé, Ricard V.; Elena, Santiago F.

2014-04-01

The distribution of mutational fitness effects (DMFE) is crucial to the evolutionary fate of quasispecies. In this article we analyze the effect of the DMFE on the dynamics of a large quasispecies by means of a phenotypic version of the classic Eigen's model that incorporates beneficial, neutral, deleterious, and lethal mutations. By parameterizing the model with available experimental data on the DMFE of Vesicular stomatitis virus (VSV) and Tobacco etch virus (TEV), we found that increasing mutation does not totally push the entire viral quasispecies towards deleterious or lethal regions of the phenotypic sequence space. The probability of finding regions in the parameter space of the general model that results in a quasispecies only composed by lethal phenotypes is extremely small at equilibrium and in transient times. The implications of our findings can be extended to other scenarios, such as lethal mutagenesis or genomically unstable cancer, where increased mutagenesis has been suggested as a potential therapy.

Toxic and hormetic-like effects of three components of citrus essential oils on adult Mediterranean fruit flies (Ceratitis capitata.

Directory of Open Access Journals (Sweden)

Stella A Papanastasiou

Full Text Available Plant essential oils (EOs and a wide range of their individual components are involved in a variety of biological interactions with insect pests including stimulatory, deterrent, toxic and even hormetic effects. Both the beneficial and toxic properties of citrus EOs on the Mediterranean fruit fly (medfly have been experimentally evidenced over the last years. However, no information is available regarding the toxic or beneficial effects of the major components of citrus EOs via contact with the adults of the Mediterranean fruit fly. In the present study, we explored the toxicity of limonene, linalool and α-pinene (3 of the main compounds of citrus EOs against adult medflies and identified the effects of sub-lethal doses of limonene on fitness traits in a relaxed [full diet (yeast and sugar] and in a stressful (sugar only feeding environment. Our results demonstrate that all three compounds inferred high toxicity to adult medflies regardless of the diet, with males being more sensitive than females. Sub-lethal doses of limonene (LD20 enhanced the lifespan of adult medflies when they were deprived of protein. Fecundity was positively affected when females were exposed to limonene sub-lethal doses. Therefore, limonene, a major constituent of citrus EOs, induces high mortality at increased doses and positive effects on life history traits of medfly adults through contact at low sub-lethal doses. A hormetic-like effect of limonene to adult medflies and its possible underlying mechanisms are discussed.

Toxicity of selenium (Na sub 2 SeO sub 3 ) and mercury (HgCl sub 2 ) on the planarian Dugesia gonocephala

Energy Technology Data Exchange (ETDEWEB)

Congiu, A.M.; Casu, S.; Ugazio, G. (Istituto di Genetica (Italy))

1989-10-01

The toxicity of selenium (Na{sub 2}SeO{sub 3}) and mercury (HgCl{sub 2}) was determined by using a freshwater planarian which is particularly sensitive to pollution, and belongs to a fissiparous breed of Dugesia gonocephala. The mortality and fissiparity frequency of the subjects were studied. They were exposed to intense treatments (48 hours) or for medium to long periods of time (21 days) to either the single compounds or a combination of both, and were fed or fasting. The lethal effect of sodium selenite is correlated to the food intake, whereas the toxicity of mercurous chloride is probably the result of a fixative effect which does not depend on feeding. The 21-day treatment with the first compound has a non-negligible lethal effect which is probably due to an accumulation phenomenon. At doses where an antioxidant effect prevails, fissiparity is stimulated. On the other hand, the second compound reduces reproduction frequency to half the base values. Compared to the Paracentrotus lividus, the Dugesia gonocephala offers various advantages concerning toxicological experiments; besides being easier to handle in the laboratory, it is available all year round and is not subject to seasonal cycles. It is also more susceptible to the toxic effect of mercury, which is a common and highly toxic pollutant, than the sea urchin.

Influence of regional hydrogeological systems at a local scale: Analyzing the coupled effects of hydrochemistry and biological activity in a Fe and CO{sub 2} rich spring

Energy Technology Data Exchange (ETDEWEB)

Menció, A., E-mail: anna.mencio@udg.edu [Grup de Geologia Aplicada i Ambiental (GAiA), Department of Environmental Sciences, University of Girona, Faculty of Sciences, Campus de Montilivi, 17071 Girona (Spain); Guasch, H., E-mail: helena.guasch@udg.edu [Grup de Recerca en Ecosistemes Continentals (GRECO), Institute of Aquatic Ecology, University of Girona, Faculty of Sciences, Campus de Montilivi, 17071 Girona (Spain); Soler, D.; Canelles, A.; Zamorano, M.; Brusi, D. [Grup de Geologia Aplicada i Ambiental (GAiA), Department of Environmental Sciences, University of Girona, Faculty of Sciences, Campus de Montilivi, 17071 Girona (Spain)

2016-11-01

A multidisciplinary approach was used in this study to determine the origin of a Fe and CO{sub 2} rich spring, an extreme freshwater system and to evaluate the coupled effects of hydrochemistry and biological activity at a local scale. An electrical resistivity tomography survey was conducted to delineate the geological context in which water emerges from a Plio-Quaternary supracrustal fault zone, and a bulk resistivity decrease was detected when CO{sub 2} rich groundwater occurred. Nine water samples, together with eight biofilm samples, and three sediment samples were taken along the spring canal for their analysis. Major ions, nutrients, and metals were analysed in water samples. Sediment analyses determined the main solid phases precipitated (mainly as CaCO{sub 3} and Fe(OH){sub 3}(a)). Biofilm analyses permitted to obtain biovolume per cell measures, total biovolume values, diatom density, chlorophyll a concentrations, and the Margalef Index values. Inverse modeling and batch reaction models were used to determine the physicochemical processes affecting the spring water, obtaining the total amount of CaCO{sub 3}/L formed; the Fe and Mn compounds, which mainly precipitated as Fe(OH){sub 3}(a) and Mn(OH){sub 2}; as well as the total CO{sub 2} released to the atmosphere. Analyzing these results together with the patterns of variation of hydrochemical and biological parameters, different interactions were observed: a) the effects of Fe inhibition in travertine formation, even though when the highest CO{sub 2} release was occurring; b) the fate and effects of chemicals limiting and/or inhibiting algal growth (mainly Fe, As and phosphate); c) the lack of coincidence between algal growth and tufa limestone precipitation; d) the relationship between some divalent metals (Mn and Co) and biotic activity. - Highlights: • Electrical resistivity tomography detected CO{sub 2} rich groundwater. • High Fe concentrations inhibits both algal growth and CaCO{sub 3

Integrated microfluidic technology for sub-lethal and behavioral marine ecotoxicity biotests

Science.gov (United States)

Huang, Yushi; Reyes Aldasoro, Constantino Carlos; Persoone, Guido; Wlodkowic, Donald

2015-06-01

Changes in behavioral traits exhibited by small aquatic invertebrates are increasingly postulated as ethically acceptable and more sensitive endpoints for detection of water-born ecotoxicity than conventional mortality assays. Despite importance of such behavioral biotests, their implementation is profoundly limited by the lack of appropriate biocompatible automation, integrated optoelectronic sensors, and the associated electronics and analysis algorithms. This work outlines development of a proof-of-concept miniaturized Lab-on-a-Chip (LOC) platform for rapid water toxicity tests based on changes in swimming patterns exhibited by Artemia franciscana (Artoxkit M™) nauplii. In contrast to conventionally performed end-point analysis based on counting numbers of dead/immobile specimens we performed a time-resolved video data analysis to dynamically assess impact of a reference toxicant on swimming pattern of A. franciscana. Our system design combined: (i) innovative microfluidic device keeping free swimming Artemia sp. nauplii under continuous microperfusion as a mean of toxin delivery; (ii) mechatronic interface for user-friendly fluidic actuation of the chip; and (iii) miniaturized video acquisition for movement analysis of test specimens. The system was capable of performing fully programmable time-lapse and video-microscopy of multiple samples for rapid ecotoxicity analysis. It enabled development of a user-friendly and inexpensive test protocol to dynamically detect sub-lethal behavioral end-points such as changes in speed of movement or distance traveled by each animal.

The role of pH in lethal effect of glucose load malignant cells

International Nuclear Information System (INIS)

Shmakova, N.L.; Yarmonenko, S.P.; Laser, K.; Fomenkova, T.E.; Kozubek, S.; Korogodin, V.I.

1985-01-01

The lethal effect of variuos pH values on Erlich ascites tumour (EAT) calls has been investigated. Different pH values were obtained by means of both glucose load and phosphate buffers. The effect has been investigated by observing cell death in vitro, determining cancerogenity of EAT cells and determining their radiosensitivity. The results of all methods enabled us to conclude that the same values of pH lead to the same effect on EAT cells independently of the way by which the given pH value was reached. The lethal effect markedly increased when the value of pH was lower than 5.6. It is concluded that the basis of the mechanism of glucose load lethal effect is their ''self-acidisation''. The measurement of pH in tumours is proposed as a basic test for determining the suitability of the use of hyperglycemia in clinics and for comparison of the efficiency of various modes of treatment

Evaluating the stress response as a bioindicator of sub-lethal effects of crude oil exposure in wild house sparrows (Passer domesticus.

Directory of Open Access Journals (Sweden)

Christine R Lattin

Full Text Available Petroleum can disrupt endocrine function in humans and wildlife, and interacts in particularly complex ways with the hypothalamus-pituitary-adrenal (HPA axis, responsible for the release of the stress hormones corticosterone and cortisol (hereafter CORT. Ingested petroleum can act in an additive fashion with other stressors to cause increased mortality, but it is not clear exactly why--does petroleum disrupt feedback mechanisms, stress hormone production, or both? This laboratory study aimed to quantify the effects of ingested Gulf of Mexico crude oil on the physiological stress response of house sparrows (Passer domesticus. We examined baseline and stress-induced CORT, negative feedback, and adrenal sensitivity in house sparrows given a 1% oil or control diet (n = 12 in each group. We found that four weeks on a 1% oil diet did not alter baseline CORT titers or efficacy of negative feedback, but significantly reduced sparrows' ability to secrete CORT in response to a standardized stressor and adrenocorticotropin hormone injection, suggesting that oil damages the steroid-synthesizing cells of the adrenal. In another group of animals on the same 1% oil (n = 9 or control diets (n = 8, we examined concentrations of eight different blood chemistry parameters, and CORT in feathers grown before and during the feeding experiments as other potential biomarkers of oil exposure. None of the blood chemistry parameters differed between birds on the oil and control diets after two or four weeks of feeding, nor did feather CORT differ between the two groups. Overall, this study suggests that the response of CORT to stressors, but not baseline HPA function, may be a particularly sensitive bioindicator of sub-lethal chronic effects of crude oil exposure.

Evaluating the stress response as a bioindicator of sub-lethal effects of crude oil exposure in wild house sparrows (Passer domesticus).

Science.gov (United States)

Lattin, Christine R; Ngai, Heather M; Romero, L Michael

2014-01-01

Petroleum can disrupt endocrine function in humans and wildlife, and interacts in particularly complex ways with the hypothalamus-pituitary-adrenal (HPA) axis, responsible for the release of the stress hormones corticosterone and cortisol (hereafter CORT). Ingested petroleum can act in an additive fashion with other stressors to cause increased mortality, but it is not clear exactly why--does petroleum disrupt feedback mechanisms, stress hormone production, or both? This laboratory study aimed to quantify the effects of ingested Gulf of Mexico crude oil on the physiological stress response of house sparrows (Passer domesticus). We examined baseline and stress-induced CORT, negative feedback, and adrenal sensitivity in house sparrows given a 1% oil or control diet (n = 12 in each group). We found that four weeks on a 1% oil diet did not alter baseline CORT titers or efficacy of negative feedback, but significantly reduced sparrows' ability to secrete CORT in response to a standardized stressor and adrenocorticotropin hormone injection, suggesting that oil damages the steroid-synthesizing cells of the adrenal. In another group of animals on the same 1% oil (n = 9) or control diets (n = 8), we examined concentrations of eight different blood chemistry parameters, and CORT in feathers grown before and during the feeding experiments as other potential biomarkers of oil exposure. None of the blood chemistry parameters differed between birds on the oil and control diets after two or four weeks of feeding, nor did feather CORT differ between the two groups. Overall, this study suggests that the response of CORT to stressors, but not baseline HPA function, may be a particularly sensitive bioindicator of sub-lethal chronic effects of crude oil exposure.

Developing a Comprehensive Risk Assessment Framework for Geological Storage CO<sub>2sub>

Energy Technology Data Exchange (ETDEWEB)

Duncan, Ian [Univ. of Texas, Austin, TX (United States)

2014-08-31

The operational risks for CCS projects include: risks of capturing, compressing, transporting and injecting CO₂; risks of well blowouts; risk that CO<sub>2sub> will leak into shallow aquifers and contaminate potable water; and risk that sequestered CO<sub>2sub> will leak into the atmosphere. This report examines these risks by using information on the risks associated with analogue activities such as CO<sub>2sub> based enhanced oil recovery (CO<sub>2sub>-EOR), natural gas storage and acid gas disposal. We have developed a new analysis of pipeline risk based on Bayesian statistical analysis. Bayesian theory probabilities may describe states of partial knowledge, even perhaps those related to non-repeatable events. The Bayesian approach enables both utilizing existing data and at the same time having the capability to adsorb new information thus to lower uncertainty in our understanding of complex systems. Incident rates for both natural gas and CO<sub>2sub> pipelines have been widely used in papers and reports on risk of CO<sub>2sub> pipelines as proxies for the individual risk created by such pipelines. Published risk studies of CO<sub>2sub> pipelines suggest that the individual risk associated with CO2 pipelines is between 10^-3 and 10^-4, which reflects risk levels approaching those of mountain climbing, which many would find unacceptably high. This report concludes, based on a careful analysis of natural gas pipeline failures, suggests that the individual risk of CO<sub>2sub> pipelines is likely in the range of 10-6 to 10-7, a risk range considered in the acceptable to negligible range in most countries. If, as is commonly thought, pipelines represent the highest risk component of CCS outside of the capture plant, then this conclusion suggests that most (if not all) previous quantitative- risk assessments of components of CCS may be orders of magnitude to high. The potential lethality of unexpected CO<sub>2sub> releases

Austerity and the embodiment of neoliberalism as ill-health: Towards a theory of biological sub-citizenship.

Science.gov (United States)

Sparke, Matthew

2017-08-01

This article charts the diverse pathways through which austerity and other policy shifts associated with neoliberalism have come to be embodied globally in ill-health. It combines a review of research on these processes of embodiment with the development of a theory of the resulting forms of biological sub-citizenship. This theory builds on other studies that have already sought to complement and complicate the concept of biological citizenship with attention to the globally uneven experience and embodiment of bioinequalities. Focused on the unevenly embodied sequelae of austerity, the proceeding theorization of biological sub-citizenship is developed in three stages of review and conceptualization: 1) Biological sub-citizenship through exclusion and conditionalization; 2) Biological sub-citizenship through extraction and exploitation; and 3) Biological sub-citizenship through financialized experimentation. In conclusion the paper argues that the analysis of biological sub-citizenship needs to remain open-ended and relational in order to contribute to socially-searching work on the social determinants of health. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of short- and long-term exposures to copper on lethal and reproductive endpoints of the harpacticoid copepod Tigriopus fulvus.

Science.gov (United States)

Biandolino, Francesca; Parlapiano, Isabella; Faraponova, Olga; Prato, Ermelinda

2018-01-01

The long-term exposure provides a realistic measurement of the effects of toxicants on aquatic organisms. The harpacticoid copepod Tigriopus fulvus has a wide geographical distribution and is considered as an ideal model organism for ecotoxicological studies for its good sensitivity to different toxicants. In this study, acute, sub-chronic and chronic toxicity tests based on lethal and reproductive responses of Tigriopus fulvus to copper were performed. The number of moults during larval development was chosen as an endpoint for sub-chronic test. Sex ratio, inhibitory effect on larval development, hatching time, fecundity, brood number, nauplii/brood, total newborn production, etc, were calculated in the chronic test (28d). Lethal effect of copper to nauplii showed the LC50-48h of 310 ± 72µgCu/L (mean ± sd). It was observed a significant inhibition of larval development at sublethal copper concentrations, after 4 and 7 d. After 4d, the EC50 value obtained for the endpoint in "moult naupliar reduction" was of 55.8 ± 2.5µgCu/L (mean ± sd). The EC50 for the inhibition of naupliar development into copepodite stage, was of 21.7 ± 4.4µgCu/L (mean ± sd), after 7 days. Among the different traits tested, copper did not affect sex ratio and growth, while fecundity and total nauplii production were the most sensitive endpoints. The reproductive endpoints offer the advantage of being detectable at very low pollutant concentrations. Copyright © 2017 Elsevier Inc. All rights reserved.

Annotating novel genes by integrating synthetic lethals and genomic information

Directory of Open Access Journals (Sweden)

Faty Mahamadou

2008-01-01

Full Text Available Abstract Background Large scale screening for synthetic lethality serves as a common tool in yeast genetics to systematically search for genes that play a role in specific biological processes. Often the amounts of data resulting from a single large scale screen far exceed the capacities of experimental characterization of every identified target. Thus, there is need for computational tools that select promising candidate genes in order to reduce the number of follow-up experiments to a manageable size. Results We analyze synthetic lethality data for arp1 and jnm1, two spindle migration genes, in order to identify novel members in this process. To this end, we use an unsupervised statistical method that integrates additional information from biological data sources, such as gene expression, phenotypic profiling, RNA degradation and sequence similarity. Different from existing methods that require large amounts of synthetic lethal data, our method merely relies on synthetic lethality information from two single screens. Using a Multivariate Gaussian Mixture Model, we determine the best subset of features that assign the target genes to two groups. The approach identifies a small group of genes as candidates involved in spindle migration. Experimental testing confirms the majority of our candidates and we present she1 (YBL031W as a novel gene involved in spindle migration. We applied the statistical methodology also to TOR2 signaling as another example. Conclusion We demonstrate the general use of Multivariate Gaussian Mixture Modeling for selecting candidate genes for experimental characterization from synthetic lethality data sets. For the given example, integration of different data sources contributes to the identification of genetic interaction partners of arp1 and jnm1 that play a role in the same biological process.

Biological effects data: Fluoride and sulfur dioxide

Energy Technology Data Exchange (ETDEWEB)

McMechan, K.J. (ed.); Holton, R.L.; Ulbricht, R.J.; Morgan , J.B.

1975-04-01

The Alumax Pacific Aluminum Corporation has proposed construction of an aluminum reduction facility near Youngs Bay at Warrenton, Oregon. This report comprises one part of the final report to Alumax on a research project entitled, Physical, Chemical and Biological Studies of Youngs Bay.'' It presents data pertaining to the potential biological effects of fluoride and sulfur dioxide, two potentially hazardous plant-stack emissions, on selected aquatic species of the area. Companion volumes provide a description of the physical characteristics the geochemistry, and the aquatic animals present in Youngs Bay and adjacent ecosystems. An introductory volume provides general information and maps of the area, and summarizes the conclusions of all four studies. The data from the two phases of the experimental program are included in this report: lethal studies on the effects of selected levels of fluoride and sulfur dioxide on the survival rate of eleven Youngs Bay faunal species from four phyla, and sublethal studies on the effects of fluoride and sulfur dioxide on the rate of primary production of phytoplankton. 44 refs., 18 figs., 38 tabs.

A comparison of the survival (LD/sub 50/30/) of a number of inbred mouse strains after X and 60Co gamma irradiation

International Nuclear Information System (INIS)

Vacha, J.; Znojil, V.; Hola, J.; Sikulova, J.

1984-01-01

The value of LD/sub 50/30/ for X and 60 Co gamma radiation was ascertained for several inbred mouse strains and the significance of interstrain differences in these parameters determined. The rank order of strains according to LD/sub 50/30/ differs as between the two types of radiation with the exception of the strains BALB/c and B10.LP/Ph, which are the least resistant to radiation-induced lethality with both types of radiation. The strain C57BL/10ScSnPh is highly resistant to X irradiation. The relative biological effectiveness of 60 Co gamma radiation as compared with X-radiation from the point of view of lethality fluctuates between 0.748 and 0.952 in individual strains, with a mean value of 0.866 +- 0.033. The RBE values do not correlate with the radiosensitivity of the strain, but they do correlate with the relative contribution to erythropoiesis of the spleen. (author)

Comparison of the survival (LD/sub 50/30/) of a number of inbred mouse strains after X and /sup 60/Co gamma irradiation

Energy Technology Data Exchange (ETDEWEB)

Vacha, J.; Znojil, V.; Hola, J.; Sikulova, J. (Ceskoslovenska Akademie Ved, Brno. Biofysikalni Ustav)

1984-01-01

The value of LD/sub 50/30/ for X and /sup 60/Co gamma radiation was ascertained for several inbred mouse strains and the significance of interstrain differences in these parameters determined. The rank order of strains according to LD/sub 50/30/ differs as between the two types of radiation with the exception of the strains BALB/c and B10.LP/Ph, which are the least resistant to radiation-induced lethality with both types of radiation. The strain C57BL/10ScSnPh is highly resistant to X irradiation. The relative biological effectiveness of /sup 60/Co gamma radiation as compared with X-radiation from the point of view of lethality fluctuates between 0.748 and 0.952 in individual strains, with a mean value of 0.866 +- 0.033. The RBE values do not correlate with the radiosensitivity of the strain, but they do correlate with the relative contribution to erythropoiesis of the spleen.

Helium Ion Microscopy (HIM) for the imaging of biological samples at sub-nanometer resolution

Science.gov (United States)

Joens, Matthew S.; Huynh, Chuong; Kasuboski, James M.; Ferranti, David; Sigal, Yury J.; Zeitvogel, Fabian; Obst, Martin; Burkhardt, Claus J.; Curran, Kevin P.; Chalasani, Sreekanth H.; Stern, Lewis A.; Goetze, Bernhard; Fitzpatrick, James A. J.

2013-12-01

Scanning Electron Microscopy (SEM) has long been the standard in imaging the sub-micrometer surface ultrastructure of both hard and soft materials. In the case of biological samples, it has provided great insights into their physical architecture. However, three of the fundamental challenges in the SEM imaging of soft materials are that of limited imaging resolution at high magnification, charging caused by the insulating properties of most biological samples and the loss of subtle surface features by heavy metal coating. These challenges have recently been overcome with the development of the Helium Ion Microscope (HIM), which boasts advances in charge reduction, minimized sample damage, high surface contrast without the need for metal coating, increased depth of field, and 5 angstrom imaging resolution. We demonstrate the advantages of HIM for imaging biological surfaces as well as compare and contrast the effects of sample preparation techniques and their consequences on sub-nanometer ultrastructure.

Lethal effects of solar radiation in proficient and deficient bacteria in repair systems

International Nuclear Information System (INIS)

Sousa Neto, A. de.

1980-01-01

A study of the lethal action of solar radiation on strains of E.coli K12, proficient or deficient in repair systems, as well as the wild type strain gene products are involved in repair of damage induced by solar radiation. The inactivation of the various bacterial strains (normalized to a dose equivalent to radiation at a wavelength 254 nm) suggests that the more energetic wavelengths of the solar spectrum (290-320 nm) could be responsible for the primary damage that occurs in the DNA. The reduction in the shoulder of the survival curve in wild type strains in indicative of induction of sub-lethal damage in this region of the curve. Analysing solar inactivation curves of the bacterial strains (normalised by spore dosimetry) together with those of the same strains irradiated with UV at 254 nm, it was evident that 254 nm is not the ideal wavelength for comparison. This analysis also indicated that in addition to damage to DNA, other factors are involved in the solar radiation inactivation of wild type strains. (author)

The evolution of lethal intergroup violence

OpenAIRE

Kelly, Raymond C.

2005-01-01

Recent findings and analyses in evolutionary biology, archaeology, and ethnology provide a favorable conjuncture for examining the evolution of lethal intergroup violence among hominids during the 2.9-million-year Paleolithic time span. Here, I seek to identify and investigate the main turning points in this evolutionary trajectory and to delineate the periodization that follows from this inquiry.

The evolution of lethal intergroup violence.

Science.gov (United States)

Kelly, Raymond C

2005-10-25

Recent findings and analyses in evolutionary biology, archaeology, and ethnology provide a favorable conjuncture for examining the evolution of lethal intergroup violence among hominids during the 2.9-million-year Paleolithic time span. Here, I seek to identify and investigate the main turning points in this evolutionary trajectory and to delineate the periodization that follows from this inquiry.

Factors affecting biological reduction of CO{sub 2} into CH{sub 4} using a hydrogenotrophic methanogen in a fixed bed reactor

Energy Technology Data Exchange (ETDEWEB)

Kim, Jae Hyung; Pak, Daewon [Seoul National University of Science and Technology, Seoul (Korea, Republic of); Chang, Won Seok [Korea District Heating Corp, Seongnam (Korea, Republic of)

2015-10-15

Biological conversion of CO{sub 2} was examined in a fixed bed reactor inoculated with anaerobic mixed culture to investigate influencing factors, the type of packing material and the composition of the feeding gas mixture. During the operation of the fixed bed reactor by feeding the gas mixture (80% H{sub 2} and 20% CO{sub 2} based on volume basis), the volumetric CO{sub 2} conversion rate was higher in the fixed bed reactor packed with sponge due to its large surface area and high mass transfer from gas to liquid phase compared with PS ball. Carbon dioxide loaded into the fixed bed reactor was not completely converted because some of H{sub 2} was used for biomass growth. When a mole ratio of H{sub 2} to CO{sub 2} in the feeding gas mixture increased from 4 to 5, CO{sub 2} was completely converted into CH{sub 4}. The packing material with large surface area is effective in treating gaseous substrate such as CO{sub 2} and H{sub 2}. H{sub 2}, electron donor, should be providing more than required according to stoichiometry because some of it is used for biomass growth.

Comparison of the lethal effects of chemical warfare nerve agents across multiple ages.

Science.gov (United States)

Wright, Linnzi K M; Lee, Robyn B; Vincelli, Nicole M; Whalley, Christopher E; Lumley, Lucille A

2016-01-22

Children may be inherently more vulnerable than adults to the lethal effects associated with chemical warfare nerve agent (CWNA) exposure because of their closer proximity to the ground, smaller body mass, higher respiratory rate, increased skin permeability and immature metabolic systems. Unfortunately, there have only been a handful of studies on the effects of CWNA in pediatric animal models, and more research is needed to confirm this hypothesis. Using a stagewise, adaptive dose design, we estimated the 24h median lethal dose for subcutaneous exposure to seven CWNA in both male and female Sprague-Dawley rats at six different developmental times. Perinatal (postnatal day [PND] 7, 14 and 21) and adult (PND 70) rats were more susceptible than pubertal (PND 28 and 42) rats to the lethal effects associated with exposure to tabun, sarin, soman and cyclosarin. Age-related differences in susceptibility were not observed in rats exposed to VM, Russian VX or VX. Published by Elsevier Ireland Ltd.

Interpretation of proton relative biological effectiveness using lesion induction, lesion repair, and cellular dose distribution

International Nuclear Information System (INIS)

Paganetti, H.

2005-01-01

Phenomenological biophysical models have been successfully used to estimate the relative biological effectiveness (RBE) of ions. The predictive power of these models is limited because they require measured dose-response data that are not necessarily available for all clinically relevant end points. Furthermore, input parameters often lack mechanistic interpretation. In order to link RBE to more fundamental biological parameters we combine the concepts of two well-established biophysical models, i.e., the phenomenological 'track structure' model and the more mechanistic 'lethal lesion/potentially lethal lesion' (LPL) model. We parametrize a relation between RBE, dose homogeneity in the cell nucleus and induction rates for different lesion types. The macroscopic dose-response relationship is described in the LPL model and the microscopic, subcellular, relationship is determined by the local dose deposition pattern. The formalism provides a framework for a mechanistic interpretation of RBE values

Sublethal Effects of Insecticide Exposure on Megacopta cribraria (Fabricius) Nymphs: Key Biological Traits and Acetylcholinesterase Activity.

Science.gov (United States)

Miao, Jin; Reisig, Dominic D; Li, Guoping; Wu, Yuqing

2016-01-01

Megacopta cribraria F. (Hemiptera: Plataspidae), the kudzu bug, is an invasive insect pest of U.S. soybean. At present, insecticide application is the primary and most effective control option for M. cribraria In this study, the potential effects of sublethal and low-lethal concentrations (LC10 and LC40) of three common insecticides on key biological traits and acetylcholinesterase (AChE) activity of the treated nymphal stage of insect were assessed. The results show that the sublethal concentration of imidacloprid significantly reduced adult emergence rate of M. cribraria A low-lethal concentration of imidacloprid significantly increased nymphal development time, but significantly decreased adult emergence rate and adult longevity. Both sublethal and low-lethal concentrations of acephate caused an increase in nymphal development time and a reduction in adult emergence rate and adult longevity. Fecundity of females was significantly reduced only by exposure to low-lethal concentrations of acephate. Sublethal and low-lethal concentrations of bifenthrin increased nymphal development time, but significantly decreased adult emergence rate. In addition, we found that the AChE activity of M. cribraria was significantly increased only by LC40 imidacloprid, but strongly inhibited by acephate. © The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America.

Operational and biological effects zones from base stations of cellular telephony

Energy Technology Data Exchange (ETDEWEB)

Geronikolou, St. A., E-mail: sgeronik@bioacademy.gr [Biomedical Research Foundation Academy of Athens, Athens (Greece); Zimeras, S., E-mail: zimste@aegean.gr [University of the Aegean, Karlovassi, Samos (Greece); Tsitomeneas, S. Th., E-mail: stsit@teipir.gr [Piraeus University of Applied Sciences, Aigaleo (Greece)

2016-03-25

The possible environmental impacts of cellular base stations are operational and biological. The operational effects comprise Εlectro-Μagnetic Interference (EMI), lightning alterations and aesthetic degradation. Both thermal and non-thermal biological effects depend on the absorption of UHF radiofrequencies used. We measured, calculated and estimated the impact zones. The results are: (a) The lightning lethal zone equal to the antenna height, (b) the EMI impact in a zone up to 40m and (c) the ICNIRP’s limits exceed to a zone of 8∼20m into the antenna’s radiation pattern (for 2G GSM and 3G UMTS station). Finally we conclude the adverse effects must not expected in a zone of more than 150m from the radiated antenna, whereas, there is possibility of stochastic effects in intermediate distances (20/40-150m).

Lethal effects of selected novel pesticides on immature stages of Trichogramma pretiosum (Hymenoptera: Trichogrammatidae).

Science.gov (United States)

Khan, Muhammad Ashraf; Ruberson, John R

2017-12-01

Trichogramma pretiosum Riley is an important egg parasitoid and biological control agent of caterpillar pests. We studied the acute toxicity of 20 pesticides (14 insecticides/miticides, three fungicides and three herbicides) exposed to recommended field rates. Egg, larval, and pupal stages of the parasitoid in their hosts were dipped in formulated solutions of the pesticides and evaluated 10 days later for percentage of host eggs with holes, number of parasitoids emerged per egg with holes, and stage-specific mortality of immature as well as adult wasps within the host eggs. Seven insecticides (buprofezin, chlorantraniliprole, spirotetramat, flonicamid, flubendiamide) and miticides (spiromesifen, cyflumetofen), one herbicide (nicosulfuron), and three fungicides (myclobutanil, pyraclostrobin, trifloxystrobin + tebuconazole) caused no significant mortality to immature stages or pre-emergent adult parasitoids relative to controls. By contrast, seven insecticides/miticides (abamectin, acetamiprid, dinotefuran, fipronil, novaluron, spinetoram, tolfenpyrad) adversely affected immature and pre-emergent adult T. pretiosum, with tolfenpyrad being particularly lethal. Two herbicides had moderate (glufosinate ammonium) to severe (s-metolachlor) acute lethal effects on the immature parasitoids. This study corroborates earlier findings with adult T. pretiosum. Over half of the pesticides - and all the fungicides - tested in the current study would appear to be compatible with the use of T. pretiosum in integrated pest management programs, with respect to acute parasitoid mortality. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Toxicity assessment of sodium fluoride in Drosophila melanogaster after chronic sub-lethal exposure.

Science.gov (United States)

Dutta, Moumita; Rajak, Prem; Khatun, Salma; Roy, Sumedha

2017-01-01

Sodium fluoride (NaF), one of the most frequently used fluoride compound is composed of Na + and F - . Apart from its use in water fluoridation, NaF also acts as a major component for different dental products like toothpastes, gels and mouth rinses etc. The present study was carried out to explore the toxic impact of chronic NaF exposure on a non-target organism, Drosophila melanogaster. The larvae exposed to different concentrations of NaF through food showed a significant increase in HSP70 expression both qualitatively and quantitatively. The altered tail length and tail intensity in Comet assay validate the increased DNA damage in treated larvae. The activity of AChE, oxidative stress marker enzymes, phase I and phase II detoxifying enzymes were found to be significantly inhibited in the treated larvae when compared to control though there was no evidence of dose dependent change in each case. The alterations in the mentioned parameters can be due to increased body Fluoride ion (F - ) concentration since the analysis with ion electrode analyzer revealed that F - concentration increased significantly with NaF treatment. Hence, the results suggest that D. melanogaster manifest prominent toxic response when subjected to chronic exposure to sub-lethal NaF concentrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Understanding the fate and biological effects of Ag- and TiO{sub 2}-nanoparticles in the environment: The quest for advanced analytics and interdisciplinary concepts

Energy Technology Data Exchange (ETDEWEB)

Schaumann, Gabriele E., E-mail: schaumann@uni-landau.de [Universität Koblenz-Landau, Institute for Environmental Sciences, Group of Environmental and Soil Chemistry, Fortstr. 7, D-76829 Landau (Germany); Philippe, Allan, E-mail: philippe@uni-landau.de [Universität Koblenz-Landau, Institute for Environmental Sciences, Group of Environmental and Soil Chemistry, Fortstr. 7, D-76829 Landau (Germany); Bundschuh, Mirco, E-mail: mirco.bundschuh@slu.se [Universität Koblenz-Landau, Institute for Environmental Sciences, Group of Ecotoxicology and Environment, Fortstr. 7, D-76829 Landau (Germany); Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment, Lennart Hjelms väg 9, SE-75007 Uppsala (Sweden); Metreveli, George, E-mail: metreveli@uni-landau.de [Universität Koblenz-Landau, Institute for Environmental Sciences, Group of Environmental and Soil Chemistry, Fortstr. 7, D-76829 Landau (Germany); Klitzke, Sondra, E-mail: sondra.klitzke@tu-berlin.de [Albert-Ludwigs-Universität Freiburg, Institute of Forest Sciences, Chair of Soil Ecology, 79085 Freiburg i.Br. (Germany); Berlin University of Technology, Institute of Ecology, Department of Soil Science, Ernst-Reuter-Platz 1, D-10587 Berlin (Germany); Rakcheev, Denis, E-mail: rakcheev@uni-landau.de [Universität Koblenz-Landau, Institute for Environmental Sciences, Group of Environmental and Soil Chemistry, Fortstr. 7, D-76829 Landau (Germany); Grün, Alexandra, E-mail: alexg@uni-koblenz.de [Universität Koblenz-Landau, Institute for Integrated Natural Sciences, Dept. of Biology, Universitätsstr. 1, D-56070 Koblenz (Germany); and others

2015-12-01

Engineered inorganic nanoparticles (EINP) from consumers' products and industrial applications, especially silver and titanium dioxide nanoparticles (NP), are emitted into the aquatic and terrestrial environments in increasing amounts. However, the current knowledge on their environmental fate and biological effects is diverse and renders reliable predictions complicated. This review critically evaluates existing knowledge on colloidal aging mechanisms, biological functioning and transport of Ag NP and TiO{sub 2} NP in water and soil and it discusses challenges for concepts, experimental approaches and analytical methods in order to obtain a comprehensive understanding of the processes linking NP fate and effects. Ag NP undergo dissolution and oxidation with Ag{sub 2}S as a thermodynamically determined endpoint. Nonetheless, Ag NP also undergo colloidal transformations in the nanoparticulate state and may act as carriers for other substances. Ag NP and TiO{sub 2} NP can have adverse biological effects on organisms. Whereas Ag NP reveal higher colloidal stability and mobility, the efficiency of NOM as a stabilizing agent is greater towards TiO{sub 2} NP than towards Ag NP, and multivalent cations can dominate the colloidal behavior over NOM. Many of the past analytical obstacles have been overcome just recently. Single particle ICP-MS based methods in combination with field flow fractionation techniques and hydrodynamic chromatography have the potential to fill the gaps currently hampering a comprehensive understanding of fate and effects also at a low field relevant concentrations. These analytical developments will allow for mechanistically orientated research and transfer to a larger set of EINP. This includes separating processes driven by NP specific properties and bulk chemical properties, categorization of effect-triggering pathways directing the EINP effects towards specific recipients, and identification of dominant environmental parameters triggering

Publication Growth in Biological Sub-Fields: Patterns, Predictability and Sustainability

Directory of Open Access Journals (Sweden)

Marco Pautasso

2012-11-01

Full Text Available Biologists are producing ever-increasing quantities of papers. The question arises of whether current rates of increase in scientific outputs are sustainable in the long term. I studied this issue using publication data from the Web of Science (1991–2010 for 18 biological sub-fields. In the majority of cases, an exponential regression explains more variation than a linear one in the number of papers published each year as a function of publication year. Exponential growth in publication numbers is clearly not sustainable. About 75% of the variation in publication growth among biological sub-fields over the two studied decades can be predicted by publication data from the first six years. Currently trendy fields such as structural biology, neuroscience and biomaterials cannot be expected to carry on growing at the current pace, because in a few decades they would produce more papers than the whole of biology combined. Synthetic and systems biology are problematic from the point of view of knowledge dissemination, because in these fields more than 80% of existing papers have been published over the last five years. The evidence presented here casts a shadow on how sustainable the recent increase in scientific publications can be in the long term.

Lethal and mutagenic effects of ion beams and γ-rays in Aspergillus oryzae.

Science.gov (United States)

Toyoshima, Yoshiyuki; Takahashi, Akemi; Tanaka, Hisaki; Watanabe, Jun; Mogi, Yoshinobu; Yamazaki, Tatsuo; Hamada, Ryoko; Iwashita, Kazuhiro; Satoh, Katsuya; Narumi, Issay

2012-12-01

Aspergillus oryzae is a fungus that is used widely in traditional Japanese fermentation industries. In this study, the lethal and mutagenic effects of different linear energy transfer (LET) radiation in freeze-dried conidia of A. oryzae were investigated. The lethal effect, which was evaluated by a 90% lethal dose, was dependent on the LET value of the ionizing radiation. The most lethal ionizing radiation among that tested was (12)C(5+) ion beams with an LET of 121keV/μm. The (12)C(5+) ion beams had a 3.6-times higher lethal effect than low-LET (0.2keV/μm) γ-rays. The mutagenic effect was evaluated by the frequency of selenate resistant mutants. (12)C(6+) ion beams with an LET of 86keV/μm were the most effective in inducing selenate resistance. The mutant frequency following exposure to (12)C(6+) ion beams increased with an increase in dose and reached 3.47×10(-3) at 700Gy. In the dose range from 0 to 700Gy, (12)C(5+) ion beams were the second most effective in inducing selenate resistance, the mutant frequency of which reached a maximum peak (1.67×10(-3)) at 400Gy. To elucidate the characteristics of mutation induced by ionizing radiation, mutations in the sulphate permease gene (sB) and ATP sulfurylase gene (sC) loci, the loss of function of which results in a selenate resistant phenotype, were compared between (12)C(5+) ion beams and γ-rays. We detected all types of transversions and transitions. For frameshifts, the frequency of a +1 frameshift was the highest in all cases. Although the incidence of deletions >2bp was generally low, deletions >20bp were characteristic for (12)C(5+) ion beams. γ-rays had a tendency to generate mutants carrying a multitude of mutations in the same locus. Both forms of radiation also induced genome-wide large-scale mutations including chromosome rearrangements and large deletions. These results provide new basic insights into the mutation breeding of A. oryzae using ionizing radiation. Crown Copyright © 2012. Published

Biological basis of combination therapy with radiation and bleomycin

Energy Technology Data Exchange (ETDEWEB)

Fukuda, H; Matsuzawa, T; Yokoyama, K; Okuyama, S; Yamaura, H [Tohoku Univ., Sendai (Japan). Research Inst. for Tuberculosis, Leprosy and Cancer

1976-01-01

The biological basis for combination therapy with radiation and bleomycin (BLM) was studied on C/sub 2/W cells growing in vitro. When BLM was added to the medium before or after irradiation, a potentiating effect was observed. The potentiation remained for 4-6 hours after irradiation. To make clear the mechanism, both type of repair from radiation damage (Elkind type and PLD) by BLM were examined. BLM didn't inhibit the Elkind type recovery but it did inhibit the repair of potentially lethal damage (PLD repair). Plateau phase C/sub 2/W cells were irradiated, incubated at 37/sup 0/C for a various number of hours, then trypsinized for colony formation. PLD repair was inhibited when BLM was added immediately after irradiation. Based on such experimental results, we treated lung cancer with combination of radiation and BLM. BLM was injected intravenously within 30 minutes after irradiation. Although it seems too early to discuss the result of the combination therapy, it is very promising.

Lethal Effect on Bacterium of Decay of Incorporated Radioactive Atoms (3H, 14C, 32P)

International Nuclear Information System (INIS)

Apelgot, Sonia

1968-01-01

The biological effect of decay of 3 H, 14 C and 32 P incorporated into a bacterium depends on the nature of the organic molecule labelled, on the position of the isotope within it and on the isotope itself. In sum, results obtained to date show that: The decay of 3 H atoms incorporated into certain macromolecules of a bacterium causes sterilization through ionization by the ß - particle emitted; transmutation is of negligible importance. This self-irradiation is comparable in effect with X-rays and is affected in a similar manner by the same factors: temperature, presence of a radioprotector, radiosensitivity of the strain. Decay of 14 C or 32 P atoms incorporated into bacterial DNA is lethal because of the transmutation effect; ionizations produced by emitted ß - particles may be disregarded. Survival curves for 32 P transmutations depend on the experimental conditions. Some of the results obtained with 32 P are similar to those obtained with X-rays, e.g. effects of temperature, radical capture and oxygen, while others are similar to those of u.v. light, e.g., effect of growth conditions. Comparative tests made with 32 P indicate that the recoil energy of transmutation is not the phenomenon responsible for the lethal effect observed. Comparison of the results obtained after X-irradiation or decay of 3 H or 32 P incorporated into the DNA of bacteria of the same strain of E. coli shows that the efficiency of a 32 P transmutation is about four times greater than that of an ionization produced at random within the same DNA. (author) [fr

Cytoplasmic superoxide dismutase and catalase activity and resistance to radiation lethality in murine tumor cells

International Nuclear Information System (INIS)

Davy, C.A.; Tesfay, Z.; Jones, J.; Rosenberg, R.C.; McCarthy, C.; Rosenberg, S.O.

1986-01-01

Reduced species of molecular oxygen are produced by the interaction of ionizing radiation with aqueous solutions containing molecular oxygen. The enzymes catalase and superoxide dismutase (SOD) are thought to function in vivo as scavengers of metabolically produced peroxide and superoxide respectively. SOD has been shown to protect against the lethal effects of ionizing radiation in vitro and in vivo. The authors have investigated the relationship between the cytosolic SOD catalase content and the sensitivity to radiation lethality of a number of murine cell lines (402AX, EL-4, MB-2T3, MB-4, MEL, P-815, SAI, SP-2, and SV-3T3). K/sub i/(CN - ) for murine Cu-Zn-SOD was determined to be 6.8 x 10 -6 M. No cytosolic Mn-SOD activity was found in any of the cell lines studied. No correlation was found between the cytosolic Cu-Zn-SOD or cytosolic catalase activity and the resistance to radiation lethality or the murine cell lines studied

Effects of melatonin in rats in the initial third stage of pregnancy exposed to sub-lethal doses of herbicides.

Science.gov (United States)

Almeida, Lécio Leone de; Teixeira, Álvaro Aguiar Coelho; Soares, Anísio Francisco; Cunha, Franklin Magliano da; Silva, Valdemiro Amaro da; Vieira Filho, Leucio Duarte; Wanderley-Teixeira, Valéria

2017-04-01

Exposure to the herbicides Paraquat (PQ) and Roundup ® may cause cell lesions due to an increase in oxidative stress levels in different biological systems, even in the reproductive system. Evaluate the possible changes in reproductive parameters and hepatic, as well as its prevention by simultaneous application of melatonin. Thirty-five female rats at the age of 3 months were divided into seven groups: three groups exposed to sub-lethal doses of the herbicides PQ (50mg/kg) and Roundup ® (500mg/kg) (n=5, G2, G3 and G4); three groups exposed to herbicides and simultaneous treatment with 10mg/kg of Melatonin (n=5, G5, G6 and G7) and control group (n=5, G1) from the first to the seventh day of pregnancy. On the seventh day of pregnancy, the rats were anesthetized and euthanized, followed by laparotomy to remove their reproductive tissues and liver. Body and ovary weights were taken and the number of implantation sites, corpora lutea, preimplantation losses, implantation rates were counted and histopathology of the implantation sites, morphometry of the surface and glandular epithelia of endometrium and hepatic oxidative stress were undertaken. The present study shows the decrease in body and ovary weight, decrease in the number of implantation sites, implantation rate, in the total number of corpora lutea and increase of preimplantation percentages were observed when compared to the G1: Fig. 1 and Table 1, (p>0.001 ANOVA/Tukey). The histopathological analysis of the implantation sites showed a disorder of the cytotrophoblast and cell degeneration within the blastocyst cavity in Fig. 4. Morphometry revealed a reduction in surface and glandular epithelia and in the diameter of the endometrial glands (Table 2; p>0.05 ANOVA/Tukey), whereas in liver, serum levels of thiobarbituric acid reactive substances (TBARS) were found to be significantly elevated (Fig. 2; p>0.001; p>0.05 ANOVA/Tukey), and serum level of reduced glutathione (GSH) was significantly lower (Fig. 3; p>0

The effect of fluoride surface modification of ceramic TiO{sub 2} on the surface properties and biological response of osteoblastic cells in vitro

Energy Technology Data Exchange (ETDEWEB)

Tiainen, H; Knychala, J; Lyngstadaas, S P; Haugen, H J [Department of Biomaterials, Institute for Clinical Dentistry, University of Oslo, PO Box 1109 Blindern, NO-0317 Oslo (Norway); Monjo, M [Department of Fundamental Biology and Health Sciences, Research Institute on Health Sciences (IUNICS), University of the Balearic Islands, Cra. de Valldemossa, km 7.5, 07122 Palma de Mallorca (Spain); Nilsen, O [Department of Chemistry, University of Oslo, PO Box 1033 Blindern, NO-0315 Oslo (Norway); Ellingsen, J E, E-mail: h.j.haugen@odont.uio.no [Oral Research Laboratory, Institute for Clinical Dentistry, University of Oslo, PO Box 1109 Blindern, NO-0317 Oslo (Norway)

2011-08-15

This study investigates the effect of fluoride surface modification on the surface properties of polycrystalline ceramic TiO{sub 2} and the biological response of murine osteoblast cells to fluoride-modified TiO{sub 2} in vitro. Fluoride concentrations up to 9 at.% were detected and the fluoride was found to bind to the surface in a ligand exchange reaction between surface hydroxyl groups and the fluoride anions from the HF. No significant changes in the surface topography were detected. In vitro experiments were performed in order to evaluate the biological response of the MC3T3-E1 cells to the fluoride-modified ceramic TiO{sub 2} surfaces. No difference in the lactate dehydrogenase (LDH) activity was seen in comparison to unmodified samples, apart from the highest fluoride concentration ({approx}9 at.%) which was found to be more toxic to the cells. Real-time PCR analysis showed no conclusive evidence for the fluoride-induced promotion of osteoblast differentiation as no significant increase in the collagen-1, osteocalcin, or BMP-2 mRNA levels was detected on the fluoride-modified ceramic TiO{sub 2} surfaces apart from one group, which showed an elevated osteocalcin level and higher number of cells. Since the observed grain boundary corrosion is also anticipated to reduce the mechanical properties of ceramic TiO{sub 2}, this surface modification method may not be an ideal method for improving the osteogenic response of ceramic TiO{sub 2} scaffolds.

The Effects of Posture, Body Armor and Other Equipment on Rifleman Lethality

National Research Council Canada - National Science Library

Kramlich, Gary R., II

2005-01-01

...? This study quantifies the effects of Soldier equipment on lethality through multi-factor logistic regression using data from range experiments with the 1st Brigade, 1st Infantry Division (Mechanized...

Effects of salinity on short-term waterborne zinc uptake, accumulation and sub-lethal toxicity in the green shore crab (Carcinus maenas)

Energy Technology Data Exchange (ETDEWEB)

Niyogi, Som, E-mail: som.niyogi@usask.ca [Department of Biology, University of Saskatchewan, Saskatoon, SK (Canada); Toxicology Centre, University of Saskatchewan, Saskatoon, SK (Canada); Bamfield Marine Sciences Centre, Bamfield, BC (Canada); Blewett, Tamzin A. [Bamfield Marine Sciences Centre, Bamfield, BC (Canada); Department of Biological Sciences, University of Alberta, Edmonton, AB (Canada); Department of Biology, McMaster University, Hamilton, ON (Canada); Gallagher, Trevor [Toxicology Centre, University of Saskatchewan, Saskatoon, SK (Canada); Fehsenfeld, Sandra [Bamfield Marine Sciences Centre, Bamfield, BC (Canada); Department of Biological Sciences, University of Manitoba, Winnipeg, MB (Canada); Department of Zoology, University of British Columbia, Vancouver, BC (Canada); Wood, Chris M. [Bamfield Marine Sciences Centre, Bamfield, BC (Canada); Department of Biology, McMaster University, Hamilton, ON (Canada); Department of Zoology, University of British Columbia, Vancouver, BC (Canada)

2016-09-15

Highlights: • Zinc accumulation in the euryhaline green crab is partially salinity dependent. • Zinc accumulates mainly in the gills of green crab during acute waterborne exposure. • Branchial zinc and calcium transport in the green crab occurs via a common pathway. • Acute waterborne Zn exposure disrupts calcium and zinc homeostasis in the green crab. - Abstract: Waterborne zinc (Zn) is known to cause toxicity to freshwater animals primarily by disrupting calcium (Ca) homeostasis during acute exposure, but its effects in marine and estuarine animals are not well characterized. The present study investigated the effects of salinity on short-term Zn accumulation and sub-lethal toxicity in the euryhaline green shore crab, Carcinus maenas. The kinetic and pharmacological properties of short-term branchial Zn uptake were also examined. Green crabs (n = 10) were exposed to control (no added Zn) and 50 μM (3.25 mg L{sup −1}) of waterborne Zn (∼25% of 96 h LC{sub 50} in 100 seawater) for 96 h at 3 different salinity regimes (100%, 60% and 20% seawater). Exposure to waterborne Zn increased tissue-specific Zn accumulation across different salinities. However, the maximum accumulation occurred in 20% seawater and no difference was recorded between 60% and 100% seawater. Gills appeared to be the primary site of Zn accumulation, since the accumulation was significantly higher in the gills relative to the hepatopancreas, haemolymph and muscle. Waterborne Zn exposure induced a slight increase in haemolymph osmolality and chloride levels irrespective of salinity. In contrast, Zn exposure elicited marked increases in both haemolymph and gill Ca levels, and these changes were more pronounced in 20% seawater relative to that in 60% or 100% seawater. An in vitro gill perfusion technique was used to examine the characteristics of short-term (1–4 h) branchial Zn uptake over an exposure concentration range of 3–12 μM (200–800 μg L{sup −1}). The rate of short

Effects of lethal and non-lethal malaria on the mononuclear phagocyte system

Directory of Open Access Journals (Sweden)

Carlos Eduardo Tosta

1983-03-01

Full Text Available The effects ofone non-lethal species ofmalarialparasite, Plasmodium yoelii, and one lethal species, P. berghei, on the mononuclear phagocyte system (MPS of BALB/c mice were studied. P. yoelii caused a greater and more sustained expansion and activation of the MPS, and the two major populations of spleen phagocytic cells-red pulp and marginal zone macrophages - exhibited a greater increase in numbers in this infection. During the course of P. berghei mataria, the spleen was progressively occupied by haematopoietic tissue and, at the terminal stage of infection, an extensive depletion of lymphocytes and macrophages was apparent. The possibility was suggested that the outcome of mataria may be inftuenced by the particular way the parasite interacts with the MPS.Estudou-se o efeito da infecção causada por espécie letal (Plasmodium berghei e não- letal (P. yoelii de plasmódio sobre o sistema de fagócitos mononucleares de camundongo BALB/c. O P. yoelii causou maior e mais prolongada expansão e ativação do sistema de macrófagos. As duas mais importantes populações de fagócitos esplênicos - macrófagos de polpa vermelha e da zona marginal - exibiam maior aumento do número de células nesta infecção. Durante a evolução da malária por P. berghei, o baço foi progressivamente ocupado por tecido hematopoiético e, na fase terminal da infecção, observou-se significativa depleção dos linfócitos e macrófagos esplênicos. Os dados apresentados indicam que a evolução da malária depende do tipo de interação entre o plasmódio e o sistema de fagócitos mononucleares.

Protective Effect of Phillyrin on Lethal LPS-Induced Neutrophil Inflammation in Zebrafish

Directory of Open Access Journals (Sweden)

Liling Yang

2017-10-01

Full Text Available Background/Aims: Forsythia suspensa Vahl. (Oleaceae fruits are widely used in traditional Chinese medicine to treat pneumonia, typhoid, dysentery, ulcers and oedema. Antibacterial and anti-inflammatory activities have been reported for phillyrin (PHN, the main ingredient in Forsythia suspensa Vahl fruits, in vitro. However, the underlying mechanisms in vivo remain poorly defined. In this study, we discovered that PHN exerted potent anti-inflammatory effects in lethal LPS-induced neutrophil inflammation by suppressing the MyD88-dependent signalling pathway in zebrafish. Methods: LPS-yolk microinjection was used to induce a lethal LPS-infected zebrafish model. The effect of PHN on the survival of zebrafish challenged with lethal LPS was evaluated using survival analysis. The effect of PHN on neutrophil inflammation grading in vivo was assessed by tracking neutrophils with a transgenic line. The effects of PHN on neutrophil production and migration were analysed by SB+ cell counts during consecutive hours after modelling. Additionally, key cytokines and members of the MyD88 signalling pathway that are involved in inflammatory response were detected using quantitative RT-PCR. To assess gene expression changes during consecutive hours after modelling, the IL-1β, IL-6, TNF-α, MyD88, TRIF, ERK1/2, JNK, IκBa and NF-κB expression levels were measured. Results: PHN could protect zebrafish against a lethal LPS challenge in a dose-dependent manner, as indicated by decreased neutrophil infltration, reduced tissue necrosis and increased survival rates. Up-regulated IL-1β, IL-6 and TNF-α expression also showed the same tendencies of depression by PHN. Critically, PHN significantly inhibited the LPS-induced activation of MyD88, IκBa, and NF-κB but did not affect the expression of ERK1/2 MAPKs or JNK MAPKs in LPS-stimulated zebrafish. Additionally, PHN regulated the MyD88/IκBα/NF-κB signalling pathway by controlling IκBα, IL-1β, IL-6, and TNF

Lethal and sub-lethal chronic effects of the herbicide diuron on seagrass.

Science.gov (United States)

Negri, Andrew P; Flores, Florita; Mercurio, Phil; Mueller, Jochen F; Collier, Catherine J

2015-08-01

Photosystem II herbicides from agricultural sources have been detected throughout nearshore tropical habitats including seagrass meadows. While PSII herbicides have been shown to inhibit growth in microalgae at low concentrations, the potential impacts of chronic low concentration exposures to seagrass health and growth have not been investigated. Here we exposed two tropical seagrass species Halodule uninervis and Zostera muelleri to elevated diuron concentrations (from 0.3 to 7.2μgl(-1)) over a 79-day period followed by a 2-week recovery period in uncontaminated seawater. PAM fluorometry demonstrated rapid effect of diuron on photosystem II (PSII) in both seagrass species at 0.3μgl(-1). This effect included significant inhibition of photosynthetic efficiency (ΔF/Fm') and inactivation of PSII (Fv/Fm) over the 11 week exposure period. Significant mortality and reductions in growth was only observed at the highest exposure concentration of 7.2μgl(-1) diuron. However, biochemical indicators demonstrated that the health of seagrass after this prolonged exposure was significantly compromised at lower concentrations. For example, the drop in C:N ratios (0.6μgl(-1)) and reduced δ(13)C (1.7μgl(-1)) in seagrass leaves indicated reduced C-assimilation from photosynthesis. Critically, the energetic reserves of the plants (as measured by starch content in the root-rhizome complex) were approximately halved following diuron exposure at and above 1.7μgl(-1). During the 2-week recovery period, the photosynthetic capacity of the seagrass improved with only plants from the highest diuron treatment still exhibiting chronic damage to PSII. This study shows that, although seagrass may survive prolonged herbicide exposures, concentrations ≥0.6μgl(-1) diuron equivalents cause measureable impacts on energetic status that may leave the plants vulnerable to other simultaneous stressors. For example, tropical seagrasses have been heavily impacted by reduced light from coastal

Lethality Index 2008-2014: Less shootings, same lethality, more opacity

Directory of Open Access Journals (Sweden)

Carlos Silva Forné

2017-11-01

Full Text Available This article evaluates the use of lethal force by Mexican federal security forces during shootings with presumed members of organized crime from 2008-2014. The authors use official data and press reports on deaths and wounded in shootings to construct indicators such as the number of dead civilians over the number of dead officials from the federal security forces and the number of dead civilians over the number of wounded civilians. In a context where certain factors that contribute to an excessive use of force become more common, the results of the study show a growing use of lethal force. This raises questions over the possible excessive use of lethal force as a normal or systematic practice. The study also shows a growing context of opacity in the information available to evaluate the use of lethal force and the general lack of a legal framework to regulate the use of lethal force in Mexico.

Differential replication of Foot-and-mouth disease viruses in mice determine lethality.

Science.gov (United States)

Cacciabue, Marco; García-Núñez, María Soledad; Delgado, Fernando; Currá, Anabella; Marrero, Rubén; Molinari, Paula; Rieder, Elizabeth; Carrillo, Elisa; Gismondi, María Inés

2017-09-01

Adult C57BL/6J mice have been used to study Foot-and-mouth disease virus (FMDV) biology. In this work, two variants of an FMDV A/Arg/01 strain exhibiting differential pathogenicity in adult mice were identified and characterized: a non-lethal virus (A01NL) caused mild signs of disease, whereas a lethal virus (A01L) caused death within 24-48h independently of the dose used. Both viruses caused a systemic infection with pathological changes in the exocrine pancreas. Virus A01L reached higher viral loads in plasma and organs of inoculated mice as well as increased replication in an ovine kidney cell line. Complete consensus sequences revealed 6 non-synonymous changes between A01L and A10NL genomes that might be linked to replication differences, as suggested by in silico prediction studies. Our results highlight the biological significance of discrete genomic variations and reinforce the usefulness of this animal model to study viral determinants of lethality. Copyright © 2017 Elsevier Inc. All rights reserved.

Lethal and mutagenic effects of ion beams and γ-rays in Aspergillus oryzae

International Nuclear Information System (INIS)

Toyoshima, Yoshiyuki; Takahashi, Akemi; Tanaka, Hisaki; Watanabe, Jun; Mogi, Yoshinobu; Yamazaki, Tatsuo; Hamada, Ryoko; Iwashita, Kazuhiro; Satoh, Katsuya; Narumi, Issay

2012-01-01

Highlights: ► We investigated the effects of different LET radiation in A. oryzae. ► Both γ-rays and ion beams induced base substitutions, frameshifts, deletions. ► Both γ-rays and ion beams induced genome-wide large-scale mutations in A. oryzae. ► Some differences in the types and frequencies of mutations were found. ► Our results provide new basic insights into the mutation breeding of A. oryzae. - Abstract: Aspergillus oryzae is a fungus that is used widely in traditional Japanese fermentation industries. In this study, the lethal and mutagenic effects of different linear energy transfer (LET) radiation in freeze-dried conidia of A. oryzae were investigated. The lethal effect, which was evaluated by a 90% lethal dose, was dependent on the LET value of the ionizing radiation. The most lethal ionizing radiation among that tested was 12 C 5+ ion beams with an LET of 121 keV/μm. The 12 C 5+ ion beams had a 3.6-times higher lethal effect than low-LET (0.2 keV/μm) γ-rays. The mutagenic effect was evaluated by the frequency of selenate resistant mutants. 12 C 6+ ion beams with an LET of 86 keV/μm were the most effective in inducing selenate resistance. The mutant frequency following exposure to 12 C 6+ ion beams increased with an increase in dose and reached 3.47 × 10 −3 at 700 Gy. In the dose range from 0 to 700 Gy, 12 C 5+ ion beams were the second most effective in inducing selenate resistance, the mutant frequency of which reached a maximum peak (1.67 × 10 −3 ) at 400 Gy. To elucidate the characteristics of mutation induced by ionizing radiation, mutations in the sulphate permease gene (sB) and ATP sulfurylase gene (sC) loci, the loss of function of which results in a selenate resistant phenotype, were compared between 12 C 5+ ion beams and γ-rays. We detected all types of transversions and transitions. For frameshifts, the frequency of a +1 frameshift was the highest in all cases. Although the incidence of deletions >2 bp was generally low

Monitoring the effects of a lepidopteran insecticide, Flubendiamide, on the biology of a non-target dipteran insect, Drosophila melanogaster.

Science.gov (United States)

Sarkar, Saurabh; Roy, Sumedha

2017-10-13

Various organisms are adversely affected when subjected to chronic fluoride exposure. This highly electronegative ion present in several insecticide formulations is found to be lethal to target pests. In the present study, Drosophila melanogaster is treated with sub-lethal concentrations of a diamide insecticide formulation, Flubendiamide. Chronic exposure to the diamide (0.5-100 μg/mL) was found to be responsible for increase in fluoride ion concentration in larval as well as adult body fluid. Interestingly, 100 μg/mL Flubendiamide exposure resulted in 107 and 298% increase in fluoride ion concentration whereas only 23 and 52% of Flubendiamide concentration increase in larval and adult body fluid, respectively. Further, in this study, selected life cycle parameters like larval duration, pupal duration and emergence time showed minimal changes, whereas percentage of emergence and fecundity revealed significant treatment-associated variation. It can be noted that nearly 79% reduction in fecundity was observed with 100 μg/mL Flubendiamide exposure. The variations in these parameters indicate probable involvement of fluoride ion in detectable alterations in the biology of the non-target model insect, D. melanogaster. Furthermore, the outcomes of life cycle study suggest change in resource allocation pattern in the treated flies. The altered resource allocation might have been sufficient to resist changes in selective life cycle parameters, but it could not defend the changes in fecundity. The significant alterations indicate a definite trade-off pattern, where the treated individuals happen to compromise. Thus, survival is apparently taking an upper hand in comparison to reproductive ability in response to Flubendiamide exposure. Graphical abstract The figure demonstrates increase in Fluoride and Flubendiamide concentrations in Drosophila melanogaster after chronic sub-lethal exposure to Flubendiamide. Treatment-induced alterations in larval and pupal duration

Forecasting of the lethality in cases of nonuniform accidental irradiation (experimental studies at external gamma irradiation of rats)

International Nuclear Information System (INIS)

Ingilizova, K.

1983-01-01

A model is suggested that enables the prediction of death probability for the body (L) within the whole lethality dose range (DL 0 -DL 100 ), on the basis of predetermined physical characteristics: in cases of uneven external wholebody irradiation. Some biological effects of 4 variants of uneven irradiation have been studied, i.e. ventro-dorsal (V-D), dorso-ventral (D-V), cranio-caudal (Cr-Ca) and caudo-cranial (Ca-Cr). The following basic conclusions have been drawn: 1. The study of the biological effects of uneven irradiation, when estimated by the lethality factor, points out the lower efficiency of the former, if compared to even irradiation. 2. The even irradiation lethality in the conducted experiments, according to the ALE data and the postradiation mortality dynamics, is determined basically by the damage of the bloodforming tissue and the animals die of bone marrow syndrome. 3. The uneven irradiation, estimated by the total weight factor, is of lower efficiency than the even one. 4. The radiation-induced hypoplasia of the studied organs is exponential in character. 5. An original model for predicting radiation mortality in cases of uneven irradiation has been constructed. The model gives the possibility of relating the alterations in the index of biological efficiency reduction to the wholebody irradiation factor, as well as to the two systems with highest radiosensitivity: red bone marrow and the small intestine. The model helps determining the numerical value of death probability, depending on the average body irradiation doses and the integral unevenness factors for RBM. (author)

Reactivation of Immunological Response in Lethally X-Irradiated Mice Treated with Isogeneic Bone Marrow

Energy Technology Data Exchange (ETDEWEB)

Stankovic, V.; Slijepcevic, M.; Hrsak, I. [Institute Ruder Boskovic, Zagreb, Yugoslavia (Croatia)

1968-08-15

Male and female C57BL/H and CBA/H mice aged 10-12 weeks were used as recipients and donors, respectively. All recipient mice were given a lethal whole-body X-irradiation dose (850 R for C57BL and 950 R for CBA mice) followed by iv injection of 10 x 106 isogeneic eosin-negative bone-marrow cells suspended in 0.5 ml of Hank's solution. The number of eosin-positive cells was less than 10%. The state of immunological responsiveness of irradiated recipients was measured at different time intervals up to 86 days after irradiation. The immune response to bacterial antigen was measured with the titre of agglutinating antibodies in serum six days after iv antigenic stimulation with a suspension of 2 x 10{sup 7} killed Salmonella typhimurium cells. The immune response to tissue antigens was evaluated by: (a) the effectiveness of the spleen cells from isologous radiation chimeric parental mice in preventing bone marrow from F{sub 1} (C57BL x CBA) hybrid donor from therapeutically affecting lethally irradiated F j recipient mice; (b) the effectiveness of the spleen cells in inducing splenom egaly in recipient F{sub 1} hybrid mice (Simonsen test). It was found that the responsiveness to bacterial antigens reappears much earlier and increases much faster than the immunological responsiveness to tissue antigens. (author)

Biological effects of space flight on SP{sub 1} traits of fenugreek

Energy Technology Data Exchange (ETDEWEB)

Rong, Xu; Jing, Yu; Jiang, Xu; Feng, Zhou; Jun, Chen [The Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Beijing Union Medical College, Beijing (China); Yougang, Liu [Tianjin Univ. of Traditional Chinese Medicine, Tianjin (China); Suqin, Sun [Department of Chemistry, Tsinghua Univ., Beijing (China)

2009-04-15

Fenugreek (Trigonella Foenum-graecum L.) seeds introduced from United Arab Emirates (UAE) were carried to the space by the recoverable satellite 'Shi Jian 8'. After space loading, the seeds were planted to be observed and investigated compared to the control group. The results showed that the germination rate declined after space loading compared to the control group. SP{sub 1} plants grew inhibited first, and then vigorously later at the seedling stage. The branch number, pods and plant weight of SP{sub 1} plants' increased. More important, single pod was changed to dual pod. At the same time, the Fourier transform infrared spectroscopy (FT-IR) was used to analyze and appraise the fenugreek SP{sub 1} seeds. The results indicated that the major components and the structures remained intact, in another word, space mutation had no obvious effect on the quality of SP{sub 1} seeds. Based on the results, some variations mutated by space flight could appear at the present generation. These variations were important to gain high yield. (authors)

Hormone-dependence of sarin lethality in rats: Sex differences and stage of the estrous cycle

Energy Technology Data Exchange (ETDEWEB)

Smith, Carl D., E-mail: carl.d.smith179.mil@mail.mil; Wright, Linnzi K.M.; Garcia, Gregory E.; Lee, Robyn B.; Lumley, Lucille A.

2015-09-15

Chemical warfare nerve agents (CWNAs) are highly toxic compounds that cause a cascade of symptoms and death, if exposed casualties are left untreated. Numerous rodent models have investigated the toxicity and mechanisms of toxicity of CWNAs, but most are limited to male subjects. Given the profound physiological effects of circulating gonadal hormones in female rodents, it is possible that the daily cyclical fluctuations of these hormones affect females' sensitivity to the lethal effects of CWNAs, and previous reports that included female subjects did not control for the stage of the hormonal cycle. The aim of the current study was to determine the 24-hour median lethal dose (LD{sub 50}) of the CWNA sarin in male, ovariectomized (OVEX) female, and female rats during different stages of the estrous cycle (diestrus, proestrus, and estrus). Additionally, baseline activity levels of plasma acetylcholinesterase, butyrylcholinesterase, and carboxylesterase were measured to determine differences among the groups. Results indicated that females in proestrus had a significantly higher LD{sub 50} of sarin compared to OVEX and estrous females. Although some sex differences were observed in the activity levels of plasma esterases, they were not consistent and likely not large enough to significantly affect the LD{sub 50}s. These results suggest that hormonal cyclicity can influence the outcome of CWNA-related studies using female rodents, and that this variability can be minimized by controlling for the stage of the cycle. Additional research is necessary to determine the precise mechanism of the observed differences because it is unlikely to be solely explained by plasma esterase activity. - Highlights: • The LD{sub 50} of sarin was determined in female rats throughout the stages of the estrous cycle. • Females in proestrus had a significantly higher LD{sub 50} compared to estrous or ovariectomized females. • No sex differences were observed between male and female

Indirect effects are involved in the production of potentially lethal damage in X irradiated escherichia coli

International Nuclear Information System (INIS)

Billen, D.

1985-01-01

When living cells are exposed to low LET radiation, 60 to 70% of the resulting lethality is said to be due to indirect effects. Using the OH radical scavengers: glycerol n-butanol, t-butanol, and NO/sub 2//sup -/. The authors observed that a radiosensitive E. coli K-12 mutant (W 3110 thy/sup -/ polAl/sup -/) lacking DNA polymerase 1 displays a markedly enhanced radioresistance when exposed to X rays in the presence of these chemicals. The extent of protection afforded by these chemicals correlated with their OH radical scavenging ability over the limited range of concentrations of the chemicals studied. (Only non-toxic concentrations of the chemicals were used). The presence of 2M glycerol during irradiation of the PolAl/sup -/ cells results in a survival level higher than that seen for the unprotected parent strain (W 3110 thy polA/sup +/)

Lethal and sub-lethal chronic effects of the herbicide diuron on seagrass

International Nuclear Information System (INIS)

Negri, Andrew P.; Flores, Florita; Mercurio, Phil; Mueller, Jochen F.; Collier, Catherine J.

2015-01-01

Highlights: • We performed chronic exposures of two seagrass species to the herbicide diuron. • Diuron affected photosystem II (PSII) at 0.3 μg l −1 and growth at 7.2 μg l −1 . • Biomarkers indicated that carbon-assimilation from photosynthesis dropped following 0.6 μg l −1 diuron exposure. • Energetic reserves in the seagrass were halved at 1.7 μg l −1 after 11 weeks. • Chronic exposure to diuron is likely to enhance the impacts of low light stress during flood plumes - Abstract: Photosystem II herbicides from agricultural sources have been detected throughout nearshore tropical habitats including seagrass meadows. While PSII herbicides have been shown to inhibit growth in microalgae at low concentrations, the potential impacts of chronic low concentration exposures to seagrass health and growth have not been investigated. Here we exposed two tropical seagrass species Halodule uninervis and Zostera muelleri to elevated diuron concentrations (from 0.3 to 7.2 μg l −1 ) over a 79-day period followed by a 2-week recovery period in uncontaminated seawater. PAM fluorometry demonstrated rapid effect of diuron on photosystem II (PSII) in both seagrass species at 0.3 μg l −1 . This effect included significant inhibition of photosynthetic efficiency (ΔF/F m ′) and inactivation of PSII (F v /F m ) over the 11 week exposure period. Significant mortality and reductions in growth was only observed at the highest exposure concentration of 7.2 μg l −1 diuron. However, biochemical indicators demonstrated that the health of seagrass after this prolonged exposure was significantly compromised at lower concentrations. For example, the drop in C:N ratios (0.6 μg l −1 ) and reduced δ 13 C (1.7 μg l −1 ) in seagrass leaves indicated reduced C-assimilation from photosynthesis. Critically, the energetic reserves of the plants (as measured by starch content in the root-rhizome complex) were approximately halved following diuron exposure at and above

Chemical and radiation induced late dominant lethal effects in mice

International Nuclear Information System (INIS)

Favor, J.; Crenshaw, J.W. Jr.; Soares, E.R.

1978-01-01

Although theoretically expected, experimental data to date have not shown dominant lethal expression to occur throughout the developmental period. Specifically, late post-implantation effects have not been demonstrated. The authors routinely use an experimental technique in which parental females mated to mutagenically treated males are allowed to give birth and wean their litter, and their uterine horns are then inspected for uterine scars indicative of live and dead embryos. In a number of experiments in which males were mutagenically treated with either chemicals or X-irradiation, a discrepancy was observed between the number of live embryos as determined by the scar technique and the number of live observed at birth, suggesting the possibility of embryonic losses at a late stage in development. Initial analyses showed that mutagenic treatment increased the percentage of these late losses. These differences were statistically significant in 2 of 3 analyses. Factors affecting statistical significance and an understanding of dominant lethal mutations are discussed. (Auth.)

Lethal critical body residues as measures of Cd, Pb, and Zn bioavailability and toxicity in the earthworm Eisenia fetida

Energy Technology Data Exchange (ETDEWEB)

Conder, J.M.; Lanno, R.P. [Oklahoma State Univ., Dept. of Zoology, Stillwater, OK (United States)

2003-07-01

Background. Earthworm heavy metal concentrations (critical body residues, CBRs) may be the most relevant measures of heavy metal bioavailability in soils and may be linkable to toxic effects in order to better assess soil ecotoxicity. However, as earthworms possess physiological mechanisms to secrete and/or sequester absorbed metals as toxicologically inactive forms, total earthworm metal concentrations may not relate well with toxicity. Objective. The objectives of this research were to: i) develop LD{sub 50}s (total earthworm metal concentration associated with 50% mortality) for Cd, Pb, and Zn; ii) evaluate the LD{sub 50} for Zn in a lethal Zn-smelter soil; iii) evaluate the lethal mixture toxicity of Cd, Pb, and Zn using earthworm metal concentrations and the toxic unit (TU) approach; and iv) evaluate total and fractionated earthworm concentrations as indicators of sublethal exposure. Methods. Earthworms (Eisenia fetida (Savigny)) were exposed to artificial soils spiked with Cd, Pb, Zn, and a Cd-Pb-Zn equitoxic mixture to estimate lethal CBRs and mixture toxicity. To evaluate the CBR developed for Zn, earthworms were also exposed to Zn-contaminated field soils receiving three different remediation treatments. Earthworm metal concentrations were measured using a procedure devised to isolate toxicologically active metal burdens via separation into cytosolic and pellet fractions. (orig.)

Lethal and sublethal effects of pesticides in the management of Polyphagotarsonemus latus (Banks) (Acari: Tarsonemidae) on Capsicum annuum L.

Science.gov (United States)

Breda, Mariana O; Oliveira, José V; Esteves Filho, Alberto B; Barbosa, Douglas Rs; Santos, Andrezo A

2017-10-01

The evaluation of lethal and sublethal effects is of great importance for a complete assessment of the total impact of chemical compounds upon pest populations and the development of management strategies. In this study, we evaluated the lethal and sublethal effects of different synthetic and botanical products on the broad mite Polyphagotarsonemus latus (Banks), a major pest of Capsicum annuum L. and other crops. Abamectin had the highest lethal effect on P. latus, followed by spiromesifen, azadirachtin, neem oil and nitrogen fertiliser + citric acid. The sublethal effects of the products were indicated by the influence on mite population growth, affecting the numbers of females, males, larvae, pupae and eggs. Furthermore, a negative instantaneous rate of increase in P. latus and repellent effects were observed. The lethal and sublethal effects of abamectin, spiromesifen, azadirachtin and neem oil significantly affect P. latus population growth, as well as causing repellence to this mite on C. annuum, and they should be considered in the integrated pest management of this mite. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Molecular basis of the mutagenic and lethal effects of ultraviolet irradiation

International Nuclear Information System (INIS)

Grossman, L.

1982-01-01

Using bacteria as a model, the molecular basis of the mutagenic and lethal effects of uv radiation is being studied. Attention is focused on the mechanism of action of uv-1 specific endonucleases in the repair of damaged DNA. The isolation and identification of similar enzymes in human cells are being conducted concurrently

Molecular mechanism of pancreatic tumor metastasis inhibition by Gd@C<sub>82sub>(OH)>22sub> and its implication for de novo design of nanomedicine

Energy Technology Data Exchange (ETDEWEB)

Kang, S. -g.; Zhou, G.; Yang, P.; Liu, Y.; Sun, B.; Huynh, T.; Meng, H.; Zhao, L.; Xing, G.; Chen, C.; Zhao, Y.; Zhou, R.

2012-09-18

Pancreatic adenocarcinoma is the most lethal of the solid tumors and the fourth-leading cause of cancer-related death in North America. Matrix metalloproteinases (MMPs) have long been targeted as a potential anticancer therapy because of their seminal role in angiogenesis and extracellular matrix (ECM) degradation of tumor survival and invasion. However, the inhibition specificity to MMPs and the molecular-level understanding of the inhibition mechanism remain largely unresolved. Here, we found that endohedral metallofullerenol Gd@C<sub>82sub>(OH)>22sub> can successfully inhibit the neoplastic activity with experiments at animal, tissue, and cellular levels. Gd@C<sub>82sub>(OH)>22sub> effectively blocks tumor growth in human pancreatic cancer xenografts in a nude mouse model. Enzyme activity assays also show Gd@C<sub>82sub>(OH)>22sub> not only suppresses the expression of MMPs but also significantly reduces their activities. We then applied large-scale molecular-dynamics simulations to illustrate the molecular mechanism by studying the Gd@C<sub>82sub>(OH)>22sub>–MMP-9 interactions in atomic detail. Our data demonstrated that Gd@C<sub>82sub>(OH)>22sub> inhibits MMP-9 mainly via an exocite interaction, whereas the well-known zinc catalytic site only plays a minimal role. Steered by nonspecific electrostatic, hydrophobic, and specific hydrogen-bonding interactions, Gd@C<sub>82sub>(OH)>22sub> exhibits specific binding modes near the ligand-specificity loop S1', thereby inhibiting MMP-9 activity. Both the suppression of MMP expression and specific binding mode make Gd@C<sub>82sub>(OH)>22sub> a potentially more effective nanomedicine for pancreatic cancer than traditional medicines, which usually target the proteolytic sites directly but fail in selective inhibition. Finally, our findings provide insights for de novo design of nanomedicines for fatal diseases such as pancreatic cancer.

Cytotoxicity and Hsp 70 induction in Hep G2 cells in response to zearalenone and cytoprotection by sub-lethal heat shock

International Nuclear Information System (INIS)

Hassen, Wafa; Golli, Emna El; Baudrimont, Isabelle; Mobio, A. Theophile; Ladjimi, M. Moncef; Creppy, E. Edmond; Bacha, Hassen

2005-01-01

Zearalenone (ZEN) is a mycotoxin with several adverse effects in laboratory and domestic animals. The mechanism of ZEN toxicity that involves mainly binding to oestrogen receptors and inhibition of macromolecules synthesis is not fully understood. Using human hepatocytes Hep G2 cells as a model, the aim of this work was (i) to investigate the ability of ZEN to induce heat shock proteins Hsp 70 and (ii) to find out the mechanisms of ZEN cytotoxicity by examining cell proliferation and protein synthesis. Our study demonstrated that ZEN induces Hsp 70 expression in a time and dose-dependant manner; this induction occurs at non-cytotoxic concentrations, it could be therefore considered as a biomarker of toxicity. A cytoprotective effect of Hsp 70 was elicited when Hep G2 cells were exposed to Sub-Lethal heat shock prior to ZEN treatment and evidenced by a reduced ZEN cytolethality. This cytoprotection suggests that Hsp 70 may constitute an important cellular defence mechanism. Finally, our data show that ZEN is cytotoxic in Hep G2 cells by inhibiting cell proliferation and total protein synthesis and pointed out oxidative damage as possible pathway involved in ZEN toxicity; however, other investigations are needed to further confirm Zen induced oxidative stress

Factors influencing circadian rhythms in acetaminophen lethality.

Science.gov (United States)

Schnell, R C; Bozigian, H P; Davies, M H; Merrick, B A; Park, K S; McMillan, D A

1984-01-01

Experiments were conducted to examine the effects of changes in lighting schedules and food consumption on circadian rhythms in acetaminophen lethality and hepatic glutathione levels in male mice. Under a normal lighting schedule (light: 06.00-18.00 h), male mice exhibited a circadian rhythm in acetaminophen lethality (peak: 18.00 h; nadir: 06.00, 10.00 h) and an inverse rhythm in hepatic glutathione concentrations (peak: 06.00, 10.00 h; nadir: 18.00 h). Under a reversed lighting schedule (light: 18.00-06.00 h) the glutathione rhythm was reversed and the rhythm in acetaminophen lethality was altered showing greater sensitivity to the drug. Under continuous light, there was a shift in the acetaminophen lethality and the hepatic glutathione rhythms. Under continuous dark, both rhythms were abolished. Under a normal lighting regimen, hepatic glutathione levels were closely correlated with food consumption; i.e., both were increased during the dark phase and decreased during the light phase. Fasting the mice for 12 h abolished the rhythms in acetaminophen lethality and hepatic glutathione levels; moreover, the lethality was increased and the hepatic glutathione levels were decreased. These experiments show that both lighting schedules and feeding can alter the circadian rhythms in acetaminophen lethality and hepatic glutathione levels in male mice.

Lethal and mutagenic effects of ion beams and γ-rays in Aspergillus oryzae

Energy Technology Data Exchange (ETDEWEB)

Toyoshima, Yoshiyuki, E-mail: toyoshima@yamasa.com [Soy Sauce Laboratory, Yamasa Corporation, 2-10-1 Araoicho, Choshi, Chiba 288-0056 (Japan); Takahashi, Akemi; Tanaka, Hisaki; Watanabe, Jun; Mogi, Yoshinobu; Yamazaki, Tatsuo [Soy Sauce Laboratory, Yamasa Corporation, 2-10-1 Araoicho, Choshi, Chiba 288-0056 (Japan); Hamada, Ryoko; Iwashita, Kazuhiro [Fundamental Research Division, National Research Institute of Brewing, 3-7-1 Kagamiyama, Higashihiroshima, Hiroshima 739-0046 (Japan); Satoh, Katsuya; Narumi, Issay [Ion Beam Mutagenesis Research Group, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

2012-12-15

Highlights: ► We investigated the effects of different LET radiation in A. oryzae. ► Both γ-rays and ion beams induced base substitutions, frameshifts, deletions. ► Both γ-rays and ion beams induced genome-wide large-scale mutations in A. oryzae. ► Some differences in the types and frequencies of mutations were found. ► Our results provide new basic insights into the mutation breeding of A. oryzae. - Abstract: Aspergillus oryzae is a fungus that is used widely in traditional Japanese fermentation industries. In this study, the lethal and mutagenic effects of different linear energy transfer (LET) radiation in freeze-dried conidia of A. oryzae were investigated. The lethal effect, which was evaluated by a 90% lethal dose, was dependent on the LET value of the ionizing radiation. The most lethal ionizing radiation among that tested was {sup 12}C{sup 5+} ion beams with an LET of 121 keV/μm. The {sup 12}C{sup 5+} ion beams had a 3.6-times higher lethal effect than low-LET (0.2 keV/μm) γ-rays. The mutagenic effect was evaluated by the frequency of selenate resistant mutants. {sup 12}C{sup 6+} ion beams with an LET of 86 keV/μm were the most effective in inducing selenate resistance. The mutant frequency following exposure to {sup 12}C{sup 6+} ion beams increased with an increase in dose and reached 3.47 × 10{sup −3} at 700 Gy. In the dose range from 0 to 700 Gy, {sup 12}C{sup 5+} ion beams were the second most effective in inducing selenate resistance, the mutant frequency of which reached a maximum peak (1.67 × 10{sup −3}) at 400 Gy. To elucidate the characteristics of mutation induced by ionizing radiation, mutations in the sulphate permease gene (sB) and ATP sulfurylase gene (sC) loci, the loss of function of which results in a selenate resistant phenotype, were compared between {sup 12}C{sup 5+} ion beams and γ-rays. We detected all types of transversions and transitions. For frameshifts, the frequency of a +1 frameshift was the highest in all

A pharmacological screen for compounds that rescue the developmental lethality of a Drosophila ATM mutant.

Science.gov (United States)

Rimkus, Stacey A; Wassarman, David A

2018-01-01

Ataxia-telangiectasia (A-T) is a neurodegenerative disease caused by mutation of the A-T mutated (ATM) gene. ATM encodes a protein kinase that is activated by DNA damage and phosphorylates many proteins, including those involved in DNA repair, cell cycle control, and apoptosis. Characteristic biological and molecular functions of ATM observed in mammals are conserved in Drosophila melanogaster. As an example, conditional loss-of-function ATM alleles in flies cause progressive neurodegeneration through activation of the innate immune response. However, unlike in mammals, null alleles of ATM in flies cause lethality during development. With the goals of understanding biological and molecular roles of ATM in a whole animal and identifying candidate therapeutics for A-T, we performed a screen of 2400 compounds, including FDA-approved drugs, natural products, and bioactive compounds, for modifiers of the developmental lethality caused by a temperature-sensitive ATM allele (ATM8) that has reduced kinase activity at non-permissive temperatures. Ten compounds reproducibly suppressed the developmental lethality of ATM8 flies, including Ronnel, which is an organophosphate. Ronnel and other suppressor compounds are known to cause mitochondrial dysfunction or to inhibit the enzyme acetylcholinesterase, which controls the levels of the neurotransmitter acetylcholine, suggesting that detrimental consequences of reduced ATM kinase activity can be rescued by inhibiting the function of mitochondria or increasing acetylcholine levels. We carried out further studies of Ronnel because, unlike the other compounds that suppressed the developmental lethality of homozygous ATM8 flies, Ronnel was toxic to the development of heterozygous ATM8 flies. Ronnel did not affect the innate immune response of ATM8 flies, and it further increased the already high levels of DNA damage in brains of ATM8 flies, but its effects were not harmful to the lifespan of rescued ATM8 flies. These results provide

A screen for F1 hybrid male rescue reveals no major-effect hybrid lethality loci in the Drosophila melanogaster autosomal genome.

Science.gov (United States)

Cuykendall, Tawny N; Satyaki, P; Ji, Shuqing; Clay, Derek M; Edelman, Nathaniel B; Kimchy, Alexandra; Li, Ling-Hei; Nuzzo, Erin A; Parekh, Neil; Park, Suna; Barbash, Daniel A

2014-10-27

Hybrid sons between Drosophila melanogaster females and D. simulans males die as 3rd instar larvae. Two genes, D. melanogaster Hybrid male rescue (Hmr) on the X chromosome, and D. simulans Lethal hybrid rescue (Lhr) on chromosome II, interact to cause this lethality. Loss-of-function mutations in either gene suppress lethality, but several pieces of evidence suggest that additional factors are required for hybrid lethality. Here we screen the D. melanogaster autosomal genome by using the Bloomington Stock Center Deficiency kit to search for additional regions that can rescue hybrid male lethality. Our screen is designed to identify putative hybrid incompatibility (HI) genes similar to Hmr and Lhr which, when removed, are dominant suppressors of lethality. After screening 89% of the autosomal genome, we found no regions that rescue males to the adult stage. We did, however, identify several regions that rescue up to 13% of males to the pharate adult stage. This weak rescue suggests the presence of multiple minor-effect HI loci, but we were unable to map these loci to high resolution, presumably because weak rescue can be masked by genetic background effects. We attempted to test one candidate, the dosage compensation gene male specific lethal-3 (msl-3), by using RNA interference with short hairpin microRNA constructs targeted specifically against D. simulans msl-3 but failed to achieve knockdown, in part due to off-target effects. We conclude that the D. melanogaster autosomal genome likely does not contain additional major-effect HI loci. We also show that Hmr is insufficient to fully account for the lethality associated with the D. melanogaster X chromosome, suggesting that additional X-linked genes contribute to hybrid lethality. Copyright © 2014 Cuykendall et al.

a-Si{sub x}C{sub 1−x}:H thin films with subnanometer surface roughness for biological applications

Energy Technology Data Exchange (ETDEWEB)

Herrera-Celis, José, E-mail: jlhc@inaoep.mx; Reyes-Betanzo, Claudia, E-mail: creyes@inaoep.mx; Itzmoyotl-Toxqui, Adrián, E-mail: aitzmo@inaoep.mx [Instituto Nacional de Astrofísica, Óptica y Electrónica, Luis Enrique Erro #1, Santa María Tonantzintla, San Andrés Cholula 72840, Puebla (Mexico); Orduña-Díaz, Abdu, E-mail: abdueve@hotmail.com; Pérez-Coyotl, Ana, E-mail: anapcoyotl@hotmail.com [Centro de Investigación en Biotecnología Aplicada del IPN, Ex-Hacienda San Juan Molino Carretera Estatal Tecuexcomac-Tepetitla Km 1.5, Tepetitla 90700, Tlaxcala (Mexico)

2015-09-15

The characterization of a-Si{sub x}C{sub 1−x}:H thin films by plasma-enhanced chemical vapor deposition with high hydrogen dilution for biological applications is addressed. A root mean square roughness less than 1 nm was measured via atomic force microscopy for an area of 25 μm{sup 2}. Structural analysis was done using Fourier transform infrared spectroscopy in the middle infrared region. It was found that under the deposition conditions, the formation of Si–C bonds is promoted. Electrical dark conductivity measurements were performed to evaluate the effect of high hydrogen dilution and to find the relation between carrier transport properties and the structural arrangement. Conductivities of the order of 10{sup −7} to 10{sup −9} S/cm at room temperature for methane–silane gas flow ratio from 0.35 to 0.85 were achieved, respectively. UV-visible spectra were used to obtain the optical band gap and the Tauc parameter. Optical band gap as wide as 3.55 eV was achieved in the regime of high carbon incorporation. Accordingly, deposition under low power density and high hydrogen dilution reduces the roughness, improves the structure of the network, and stabilizes the film properties as a greater percentage of carbon is incorporated. The biofunctionalization of a-Si{sub x}C{sub 1−x}:H surfaces with NH{sub 2}-terminated self-assembled monolayers was obtained through silanization with 3-aminopropyltrimethoxysilane. This knowledge opens a window for the inclusion of these a-Si{sub x}C{sub 1−x}:H thin films in devices such as biosensors.

Functional diversity of non-lethal effects, chemical camouflage, and variation in fish avoidance in colonizing beetles.

Science.gov (United States)

Resetarits, William J; Pintar, Matthew R

2016-12-01

Predators play an extremely important role in natural communities. In freshwater systems, fish can dominate sorting both at the colonization and post-colonization stage. Specifically, for many colonizing species, fish can have non-lethal, direct effects that exceed the lethal direct effects of predation. Functionally diverse fish species with a range of predatory capabilities have previously been observed to elicit functionally equivalent responses on oviposition in tree frogs. We tested this hypothesis of functional equivalence of non-lethal effects for four predatory fish species, using naturally colonizing populations of aquatic beetles. Among taxa other than mosquitoes, and with the exception of the chemically camouflaged pirate perch, Aphredoderus sayanus, we provide the first evidence of variation in colonization or oviposition responses to different fish species. Focusing on total abundance, Fundulus chrysotus, a gape-limited, surface-feeding fish, elicited unique responses among colonizing Hydrophilidae, with the exception of the smallest and most abundant taxa, Paracymus, while Dytiscidae responded similarly to all avoided fish. Neither family responded to A. sayanus. Analysis of species richness and multivariate characterization of the beetle assemblages for the four fish species and controls revealed additional variation among the three avoided species and confirmed that chemical camouflage in A. sayanus results in assemblages essentially identical to fishless controls. The origin of this variation in beetle responses to different fish is unknown, but may involve variation in cue sensitivity, different behavioral algorithms, or differential responses to species-specific fish cues. The identity of fish species occupying aquatic habitats is crucial to understanding community structure, as varying strengths of lethal and non-lethal effects, as well as their interaction, create complex landscapes of predator effects and challenge the notion of functional

Synthesis and properties of ZnFe{sub 2}O{sub 4} replica with biological hierarchical structure

Energy Technology Data Exchange (ETDEWEB)

Liu, Hongyan; Guo, Yiping, E-mail: ypguo@sjtu.edu.cn; Zhang, Yangyang; Wu, Fen; Liu, Yun; Zhang, Di, E-mail: zhangdi@sjtu.edu.cn

2013-09-20

Highlights: • ZFO replica with hierarchical structure was synthesized from butterfly wings. • Biotemplate has a significant impact on the properties of ZFO material. • Our method opens up new avenues for the synthesis of spinel ferrites. -- Abstract: ZnFe{sub 2}O{sub 4} replica with biological hierarchical structure was synthesized from Papilio paris by a sol–gel method followed by calcination. The crystallographic structure and morphology of the obtained samples were characterized by X-ray diffraction, field-emission scanning electron microscope, and transmittance electron microscope. The results showed that the hierarchical structures were retained in the ZFO replica of spinel structure. The magnetic behavior of such novel products was measured by a vibrating sample magnetometer. A superparamagnetism-like behavior was observed due to nanostructuration size effects. In addition, the ZFO replica with “quasi-honeycomb-like structure” showed a much higher specific capacitance of 279.4 F g{sup −1} at 10 mV s{sup −1} in comparison with ZFO powder of 137.3 F g{sup −1}, attributing to the significantly increased surface area. These results demonstrated that ZFO replica is a promising candidate for novel magnetic devices and supercapacitors.

Sub-terahertz resonance spectroscopy of biological macromolecules and cells

Science.gov (United States)

Globus, Tatiana; Moyer, Aaron; Gelmont, Boris; Khromova, Tatyana; Sizov, Igor; Ferrance, Jerome

2013-05-01

Recently we introduced a Sub-THz spectroscopic system for characterizing vibrational resonance features from biological materials. This new, continuous-wave, frequency-domain spectroscopic sensor operates at room temperature between 315 and 480 GHz with spectral resolution of at least 1 GHz and utilizes the source and detector components from Virginia Diode, Inc. In this work we present experimental results and interpretation of spectroscopic signatures from bacterial cells and their biological macromolecule structural components. Transmission and absorption spectra of the bacterial protein thioredoxin, DNA and lyophilized cells of Escherichia coli (E. coli), as well as spores of Bacillus subtillis and B. atrophaeus have been characterized. Experimental results for biomolecules are compared with absorption spectra calculated using molecular dynamics simulation, and confirm the underlying physics for resonance spectroscopy based on interactions between THz radiation and vibrational modes or groups of modes of atomic motions. Such interactions result in multiple intense and narrow specific resonances in transmission/absorption spectra from nano-gram samples with spectral line widths as small as 3 GHz. The results of this study indicate diverse relaxation dynamic mechanisms relevant to sub-THz vibrational spectroscopy, including long-lasting processes. We demonstrate that high sensitivity in resolved specific absorption fingerprints provides conditions for reliable detection, identification and discrimination capability, to the level of strains of the same bacteria, and for monitoring interactions between biomaterials and reagents in near real-time. Additionally, it creates the basis for the development of new types of advanced biological sensors through integrating the developed system with a microfluidic platform for biomaterial samples.

Induction of dominant lethal mutations by gamma irradiation of Gallus domesticus spermatozoa

Energy Technology Data Exchange (ETDEWEB)

Baumgartner, J; Grom, A; Csuka, J; Kindlova, L [Poultry Research Institute, Ivanka pri Dunaji (Czechoslovakia)

1977-01-01

Mixed semen of Gallus domesticus cocks was gamma irradiated in vitro with exposures of 500, 1000, 2000, and 3000 R at the exposure rate of 5.86 Rs/sup -1/. After the irradiation the semen was applied to experimental and control layer hens, the embryonic mortality in F/sub 1/ was observed, the total number of incubated eggs was 3344. Irradiation with 500 R had a favourable influence on embryonic vitality, the exposures 1000, 2000, and 3000 R resulted in increased embryonic mortality, for 2100 R a 50% mortality of offspring was found. Induced dominant lethality was manifest during embryonic and oviduct development. The frequency of induced dominant lethality for exposures used was 19.2, 9.9, 48.3, and 69.1%, the values of mutation rate were 0.087, 0.104, 0.659, and 1.174. The mutation rate had a linear course, the value of the lethal hit per gamete for 1 R was 1.04x10/sup -4/.

Biological responses of two marine organisms of ecological relevance to on-going ocean acidification and global warming.

Science.gov (United States)

Gomiero, A; Bellerby, R G J; Manca Zeichen, M; Babbini, L; Viarengo, A

2018-05-01

Recently, there has been a growing concern that climate change may rapidly and extensively alter global ecosystems with unknown consequences for terrestrial and aquatic life. While considerable emphasis has been placed on terrestrial ecology consequences, aquatic environments have received relatively little attention. Limited knowledge is available on the biological effects of increments of seawater temperature and pH decrements on key ecological species, i.e., primary producers and/or organisms representative of the basis of the trophic web. In the present study, we addressed the biological effects of global warming and ocean acidification on two model organisms, the microbenthic marine ciliate Euplotes crassus and the green alga Dunaliella tertiocleta using a suite of high level ecological endpoint tests and sub-lethal stress measures. Organisms were exposed to combinations of pH and temperature (TR1: 7.9 [pH], 25.5 °C and TR2: 7.8 [pH], 27,0 °C) simulating two possible environmental scenarios predicted to occur in the habitats of the selected species before the end of this century. The outcomes of the present study showed that the tested scenarios did not induce a significant increment of mortality on protozoa. Under the most severe exposure conditions, sub-lethal stress indices show that pH homeostatic mechanisms have energetic costs that divert energy from essential cellular processes and functions. The marine protozoan exhibited significant impairment of the lysosomal compartment and early signs of oxidative stress under these conditions. Similarly, significant impairment of photosynthetic efficiency and an increment in lipid peroxidation were observed in the autotroph model organism held under the most extreme exposure condition tested. Copyright © 2018 Elsevier Ltd. All rights reserved.

Impact of Amorphous Silica Nanoparticles on a Living Organism: Morphological, Behavioural and Molecular Biology Implications.

Directory of Open Access Journals (Sweden)

Alfredo eAmbrosone

2014-09-01

Full Text Available It is generally accepted that silica (SiO2 is not toxic. But the increasing use of silica nanoparticles (SiO2NPs in many different industrial fields has prompted the careful investigation of its toxicity in biological systems. In this report, we describe the effects elicited by SiO2NPs on animal and cell physiology. Stable and monodisperse amorphous silica nanoparticles 25nm in diameter, were administered to living Hydra vulgaris (Cnidaria. The dose-related effects were defined by morphological and behavioural assays. The results revealed an all-or-nothing lethal toxicity with a rather high threshold (35nM NPs and a LT50 of 38h. At sub lethal doses the morpho-physiological effects included: animal morphology alterations, paralysis of the gastric region, disorganization and depletion of tentacle specialized cells, increase of apoptotic and collapsed cells and reduction of the epithelial cell proliferation rate. Transcriptome analysis (RNAseq revealed 45 differentially expressed genes, mostly involved in stress response and cuticle renovation. Our results show that Hydra reacts to SiO2NPs, is able to rebalance the animal homeostasis up to a relatively high doses of SiO2NPs and that the physiological modifications are transduced to gene expression modulation.

Lethal and sublethal effects of glyphosate (roundup active) to embryos of colombian anurans

International Nuclear Information System (INIS)

Triana Velasquez, Teofila Maria; Montes Rojas, Claudia; Bernal Bautista, Manuel Hernando

2013-01-01

Glyphosate is an herbicide widely used in agriculture, which may affect non-target species. the aim of this study was to determine the lethal (median lethal concentration - LC 5 0) and sublethal effects (changes on body size and development) of glyphosate (roundup active) to embryos of four anuran species, exposed during 96 hours under laboratory and microcosm tests. under laboratory conditions, engystomops pustulosus was the most tolerant species (LC 5 0 = 3033,18 ?g a.e./L) and rhinella marina was the most sensitive (lc50 = 1421,46 ?g a.e./L), which also showed a delayed development and significantly reduced body size. The other species had an intermediate LC50 (Rhinella humboldti = 2899.54 ?g a.e./L; hypsiboas crepitans = 2151,88 ?g a.e./L). In all cases, the laboratory LC 5 0 was lower than the concentration used in field (5392.92 ?g a.e./L), indicating a high toxic effect. In the microcosm tests, embryos of e. pustulosus were the most tolerant (LC 5 0 = 19,41 kg a.e./ha), while R. humboldti were the most sensitive (LC 5 0 = 10,61 kg a.e./ha). In this case, all four study species had a higher LC 5 0 than the concentration sprayed in field (3,69 kg a.e./ ha), so a lower lethal effect, and there were no significant differences in body size and development. This result shows that the glyphosate, as the commercial presentation roundup active, produce a moderate mortality on anuran embryos.

A bacterial cocaine esterase protects against cocaine-induced epileptogenic activity and lethality.

Science.gov (United States)

Jutkiewicz, Emily M; Baladi, Michelle G; Cooper, Ziva D; Narasimhan, Diwahar; Sunahara, Roger K; Woods, James H

2009-09-01

Cocaine toxicity results in cardiovascular complications, seizures, and death and accounts for approximately 20% of drug-related emergency department visits every year. Presently, there are no treatments to eliminate the toxic effects of cocaine. The present study hypothesizes that a bacterial cocaine esterase with high catalytic efficiency would provide rapid and robust protection from cocaine-induced convulsions, epileptogenic activity, and lethality. Cocaine-induced paroxysmal activity and convulsions were evaluated in rats surgically implanted with radiotelemetry devices (N=6 per treatment group). Cocaine esterase was administered 1 minute after a lethal dose of cocaine or after cocaine-induced convulsions to determine the ability of the enzyme to prevent or reverse, respectively, the effects of cocaine. The cocaine esterase prevented all cocaine-induced electroencephalographic changes and lethality. This effect was specific for cocaine because the esterase did not prevent convulsions and death induced by a cocaine analog, (-)-2beta-carbomethoxy-3beta-phenyltropane. The esterase prevented lethality even after cocaine-induced convulsions occurred. In contrast, the short-acting benzodiazepine, midazolam, prevented cocaine-induced convulsions but not the lethal effects of cocaine. The data showed that cocaine esterase successfully degraded circulating cocaine to prevent lethality and that cocaine-induced convulsions alone are not responsible for the lethal effects of cocaine in this model. Therefore, further investigation into the use of cocaine esterase for treating cocaine overdose and its toxic effects is warranted.

Countermeasures for Space Radiation Induced Malignancies and Acute Biological Effects

Science.gov (United States)

Kennedy, Ann

The hypothesis being evaluated in this research program is that control of radiation induced oxidative stress will reduce the risk of radiation induced adverse biological effects occurring as a result of exposure to the types of radiation encountered during space travel. As part of this grant work, we have evaluated the protective effects of several antioxidants and dietary supplements and observed that a mixture of antioxidants (AOX), containing L-selenomethionine, N-acetyl cysteine (NAC), ascorbic acid, vitamin E succinate, and alpha-lipoic acid, is highly effective at reducing space radiation induced oxidative stress in both in vivo and in vitro systems, space radiation induced cytotoxicity and malignant transformation in vitro [1-7]. In studies designed to determine whether the AOX formulation could affect radiation induced mortality [8], it was observed that the AOX dietary supplement increased the 30-day survival of ICR male mice following exposure to a potentially lethal dose (8 Gy) of X-rays when given prior to or after animal irradiation. Pretreatment of animals with antioxidants resulted in significantly higher total white blood cell and neutrophil counts in peripheral blood at 4 and 24 hours following exposure to doses of 1 Gy and 8 Gy. Antioxidant treatment also resulted in increased bone marrow cell counts following irradiation, and prevented peripheral lymphopenia following 1 Gy irradiation. Supplementation with antioxidants in irradiated animals resulted in several gene expression changes: the antioxidant treatment was associated with increased Bcl-2, and decreased Bax, caspase-9 and TGF-β1 mRNA expression in the bone marrow following irradiation. These results suggest that modulation of apoptosis may be mechanistically involved in hematopoietic system radioprotection by antioxidants. Maintenance of the antioxidant diet was associated with improved recovery of the bone marrow following sub-lethal or potentially lethal irradiation. Taken together

Heterochromatin position effects on circularized sex chromosomes cause filicidal embryonic lethality in Drosophila melanogaster.

Science.gov (United States)

Ferree, Patrick M; Gomez, Karina; Rominger, Peter; Howard, Dagnie; Kornfeld, Hannah; Barbash, Daniel A

2014-04-01

Some circularized X-Y chromosomes in Drosophila melanogaster are mitotically unstable and induce early embryonic lethality, but the genetic basis is unknown. Our experiments suggest that a large region of X-linked satellite DNA causes anaphase bridges and lethality when placed into a new heterochromatic environment within certain circularized X-Y chromosomes. These results reveal that repetitive sequences can be incompatible with one another in cis. The lethal phenotype also bears a remarkable resemblance to a case of interspecific hybrid lethality.

Non-Lethal Weaponry: A Framework for Future Integration

Science.gov (United States)

1998-04-01

community, but was widely popularized by John Naisbitt in his 1982 work, Megatrends . In short, it asserts that much may be learned about a dynamic, but...Notes 1 John Naisbitt, Megatrends : Ten New Directions Transforming Our Lives (New York, NY: Warner Books, Inc., 1982), 3-5. 2 Robert J. Bunker...lethals by opponents of biological and chemical weapons. The use of chemical agents…is seen as a Trojan Horse to circumvent the Chemical Weapons

Inhibitory action of chlorophyllin of autosome recessive lethals induced by irradiation

International Nuclear Information System (INIS)

Salceda, V.M.; Pimentel, P.A.E.; Cruces, M.P.

2006-01-01

The chlorophyllin is a sodium salt of the chlorophyll that has a strong protective action of the damage induced by different agents so much physical as chemical. In Drosophila there is reported this effect in somatic cells. In contrast, in germinal cells using tests with the sexual chromosomes has not been found such inhibitory action. For this reason, in this occasion we will refer to the effect of the lethality induced in autosome chromosomes, in particular to the chromosome II of this species. For such effect groups of males of the line Canton-S its were pre-treated for 24h with or without 69 mm of CCS and later on treaties with or without 40 Gy of gamma irradiation. The males were then subjected to the technical Cy L / Pm for the detection of recessive lethals. In the third generation the respective counts of the descendant of each one of them to determine the corresponding categories for each extracted chromosome were made. To be mendelian crosses it is expected for a normal chromosome a proportion 2:1 of individuals with genotype Cy L / +: +/+. The absence of individuals +/+ it is indicative of a lethal gene, until 10% of these individuals of each male's total descendant, it is considered that is carrying of a semi lethal gene. The sum of lethal and semi lethals constitutes the category detrimental. The obtained results indicated that the pre-treatment with CCS reduces in a significant way the frequency of induced lethals by 40 Gy of gamma rays. The fact that an effect inhibitor has not been observed in the test of recessive lethal bound to the sex obtained previously, it contrasts with the effect observed in the chromosome II, results of this study and with the one observed in the chromosome III in somatic cells. The above-mentioned shows a differential action of the CCS between sexual chromosomes and autosomal before the effect of the gamma radiation. At the moment we don't have an explanation to these evidences. To evaluate the action of the chlorophyllin

Genotoxic endpoints in the earthworms sub-lethal assay to evaluate natural soils contaminated by metals and radionuclides

International Nuclear Information System (INIS)

Lourenco, Joana I.; Pereira, Ruth O.; Silva, Ana C.; Morgado, Jose M.; Carvalho, Fernando P.; Oliveira, Joao M.; Malta, Margarida P.; Paiva, Artur A.; Mendo, Sonia A.; Goncalves, Fernando J.

2011-01-01

Eisenia andrei was exposed, for 56 days, to a contaminated soil from an abandoned uranium mine and to the natural reference soil LUFA 2.2. The organisms were sampled after 0, 1, 2, 7, 14 and 56 days of exposure, to assess metals bioaccumulation, coelomocytes DNA integrity and cytotoxicity. Radionuclides bioaccumulation and growth were also determined at 0 h, 14 and 56 days of exposure. Results have shown the bioaccumulation of metals and radionuclides, as well as, growth reduction, DNA damages and cytotoxicity in earthworms exposed to contaminated soil. The usefulness of the comet assay and flow cytometry, to evaluate the toxicity of contaminants such as metals and radionuclides in earthworms are herein reported. We also demonstrated that DNA strand breakage and immune cells frequency are important endpoints to be employed in the earthworm reproduction assay, for the evaluation of soil geno and cytotoxicity, as part of the risk assessment of contaminated areas. This is the first study that integrates DNA damage and cytotoxicity evaluation, growth and bioaccumulation of metals and radionuclides in a sub lethal assay, for earthworms exposed to soil contaminated with metals and radionuclides.

Genotoxic endpoints in the earthworms sub-lethal assay to evaluate natural soils contaminated by metals and radionuclides

Energy Technology Data Exchange (ETDEWEB)

Lourenco, Joana I., E-mail: joanalourenco@ua.pt [CESAM and Departamento de Biologia, Universidade de Aveiro, Campus Universitario de Santiago, 3810-193 Aveiro (Portugal); Pereira, Ruth O., E-mail: ruthp@ua.pt [CESAM and Departamento de Biologia, Universidade de Aveiro, Campus Universitario de Santiago, 3810-193 Aveiro (Portugal); Silva, Ana C., E-mail: ana.cmj@ua.pt [CESAM and Departamento de Biologia, Universidade de Aveiro, Campus Universitario de Santiago, 3810-193 Aveiro (Portugal); Morgado, Jose M., E-mail: jmtmorgado@gmail.com [Centro de Histocompatibilidade do Centro, Praceta Prof. Mota Pinto, Edificio S. Jeronimo, 4o piso, Apartado 9041, 3001-301 Coimbra (Portugal); Carvalho, Fernando P., E-mail: fernando.carvalho@itn.pt [Instituto Tecnologico Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal); Oliveira, Joao M., E-mail: joaomota@itn.pt [Instituto Tecnologico Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal); Malta, Margarida P., E-mail: margm@itn.pt [Instituto Tecnologico Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal); Paiva, Artur A., E-mail: apaiva@histocentro.min-saude.pt [Centro de Histocompatibilidade do Centro, Praceta Prof. Mota Pinto, Edificio S. Jeronimo, 4o piso, Apartado 9041, 3001-301 Coimbra (Portugal); Mendo, Sonia A., E-mail: smendo@ua.pt [CESAM and Departamento de Biologia, Universidade de Aveiro, Campus Universitario de Santiago, 3810-193 Aveiro (Portugal); Goncalves, Fernando J., E-mail: fjmg@ua.pt [CESAM and Departamento de Biologia, Universidade de Aveiro, Campus Universitario de Santiago, 3810-193 Aveiro (Portugal)

2011-02-15

Eisenia andrei was exposed, for 56 days, to a contaminated soil from an abandoned uranium mine and to the natural reference soil LUFA 2.2. The organisms were sampled after 0, 1, 2, 7, 14 and 56 days of exposure, to assess metals bioaccumulation, coelomocytes DNA integrity and cytotoxicity. Radionuclides bioaccumulation and growth were also determined at 0 h, 14 and 56 days of exposure. Results have shown the bioaccumulation of metals and radionuclides, as well as, growth reduction, DNA damages and cytotoxicity in earthworms exposed to contaminated soil. The usefulness of the comet assay and flow cytometry, to evaluate the toxicity of contaminants such as metals and radionuclides in earthworms are herein reported. We also demonstrated that DNA strand breakage and immune cells frequency are important endpoints to be employed in the earthworm reproduction assay, for the evaluation of soil geno and cytotoxicity, as part of the risk assessment of contaminated areas. This is the first study that integrates DNA damage and cytotoxicity evaluation, growth and bioaccumulation of metals and radionuclides in a sub lethal assay, for earthworms exposed to soil contaminated with metals and radionuclides.

RBE-LET relationships for different types of lethal radiation damage in mammalian cells: comparison with DNA dsb and an interpretation of differences in radiosensitivity

NARCIS (Netherlands)

Barendsen, G. W.

1994-01-01

Relative biological effectiveness (RBE), as a function of linear energy transfer (LET), is evaluated for different types of damage contributing to mammalian cell reproductive death. Survival curves are analysed assuming a linear-quadratic dose dependence of lethal lesions. The linear term represents

Radiation biology using synchrotron radiation. In relation to radiation chemistry as an initial process

International Nuclear Information System (INIS)

Kobayashi, Katsumi

1995-01-01

Radiation biology using synchrotron radiation have been investigated, focusing on the mechanism of the formation of molecular damage. This paper introduces recent outcome of these studies. First, the process from imparted energy to the formation of molecular damage is outlined. The previous studies can be largely categorized as dealing with (1) biological effects of inner-shell ionization on elements composing the living body and (2) X-ray energy dependence of biological effects. Bromine and phosphorus are used as elements for the study of inner-cell ionization. In the study on lethal effects of monochromatic soft X-rays on the BrdUMP-incorporated yeast cells, Auger enhancement was found to occur. The first report on the effects of K-shell absorption of cellular phosphorus atoms has revealed that biological effects on cellular lethality and genetic changes was enhanced by 40%. Plasmid DNA and oligonucleotide have been used to study biological effects of vacuum ultraviolet rays to monochromatic soft X-ray, which makes it possible to study strand breaks. Because experimental production of energy required for the formation of double strand breaks has become possible, synchrotron radiation plays a very important role in radiation biological studies. Finally, future issues are presented. (N.K.)

Lethality of patients with rheumatoid arthritis depending on adalimumab administration: imitation modeling

Directory of Open Access Journals (Sweden)

D V Goryachev

2009-01-01

Full Text Available Lethality of pts with rheumatoid arthritis (RA exceeds mortality values in general population. Possibility of disease modifying anti-rheumatic drugs (DMARD influence on RA pts lethality has been widely discussed lately in scientific works. Objective. To determine possible lethality diminishment in Russian population of RA pts with one of biological drugs TNFα antagonist adalimumab. Material and methods. Model construction is based on the fact of lethality dependence on pt functional state assessed by HAQ. Model simulating progression of functional disability in pts with RA visiting medical institutions of Russia was made (RAISER study. 3 model variants for imitation of consecutive change of DMARDs including adalimumab were done. First consecution assessed DMARD change in the next chain: adalimumab-methotrexate-sulfasalazine-leflunomide-azathioprine-cyclosporine-palliative therapy. Second consecution: adalimumab administration after failure of first 3 DMARDs. Third consecution considered only change of synthetic DMARDs without adalimumab inclusion. Model imitated participation of 3000 pts in every consecution. Prognosis horizon was 12 years. Age of pts and initial HAQ distribution were get from results of epidemiological RAISER study. Calculation was done on the base of elevation of standardized lethality level (SLL in population of RA pts in average from 135% to 300%. SLL values from 80 to 320% were used depending on functional disability degree with converting to Russian values of age-specific lethality coefficient for 1999. Results. Lethality in treatment consecutions including adalimumab was significantly lower. To the end of 12th year in group not using adalimumab, using it at once and using it after 376 DMARDs respectively 65,1%, 71,6% and 71,1% of pts were still alive. Conclusion. Significant decrease of lethality with adalimumab inclusion in consecution of DMARD change during treatment of RA pts was demonstrated with imitation modeling

Effect of coagulation on treatment of municipal wastewater reverse osmosis concentrate by UVC/H{sub 2}O{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Umar, Muhammad; Roddick, Felicity, E-mail: felicity.roddick@rmit.edu.au; Fan, Linhua

2014-02-15

Highlights: • Alum coagulation is an effective pre-treatment for UVC/H{sub 2}O{sub 2} treatment of high salinity ROC. • Comparable DOC in samples but different coagulation success due to different nature of organics. • Comparable mineralization obtained for two different ROCs with UVC/H{sub 2}O{sub 2} only treatment. • UVC/H{sub 2}O{sub 2} treatment led to increased biodegradability with and without coagulation. • Significant reduction in energy consumption obtained after pre- and biological post-treatment. -- Abstract: Disposal of reverse osmosis concentrate (ROC) is a growing concern due to potential health and ecological risks. Alum coagulation was investigated as pre-treatment for the UVC/H{sub 2}O{sub 2} treatment of two high salinity ROC samples (ROC A and B) of comparable organic and inorganic content. Coagulation removed a greater fraction of the organic content for ROC B (29%) than ROC A (16%) which correlated well with the reductions of colour and A{sub 254}. Although the total reductions after 60 min UVC/H{sub 2}O{sub 2} treatment with and without coagulation were comparable, large differences in the trends of reduction were observed which were attributed to the different nature of the organic content (humic-like) of the samples as indicated by the LC-OCD analyses and different initial (5% and 16%) biodegradability. Coagulation and UVC/H{sub 2}O{sub 2} treatment preferentially removed humic-like compounds which resulted in low reaction rates after UVC/H{sub 2}O{sub 2} treatment of the coagulated samples. The improvement in biodegradability was greater (2–3-fold) during UVC/H{sub 2}O{sub 2} treatment of the pre-treated samples than without pre-treatment. The target DOC residual (≤15 mg/L) was obtained after 30 and 20 min irradiation of pre-treated ROC A and ROC B with downstream biological treatment, corresponding to reductions of 55% and 62%, respectively.

Comparative influence of dose rate and radiation nature, on lethality after big mammals irradiation

International Nuclear Information System (INIS)

Destombe, C.; Le Fleche, Ph.; Grasseau, A.; Reynal, A.

1997-01-01

For the same dose and the 30 days lethality as biological criterion, the dose rate influence is more important than the radiation nature on the results of an big mammals total body irradiation. (authors)

The effects of radiation dose-rate and quality on the induction of dominant lethals in mouse spermatids

International Nuclear Information System (INIS)

Searle, A.G.; Beechey, G.V.

1981-01-01

Hybrid male mice were given 3 Gy (300 rad) doses of X- or γ-irradiation at dose-rates of either 0.6 or 0.002 Gy/min for each radiation. Germ-cells treated as spermatids were tested for dominant lethality. Effects on spermatogonia were evaluated by studying testis-weight, sperm-count and sperm abnormalities. The rate of induction of dominant lethal mutations was 2.1 times as high after acute X-irradiation as after protracted γ-irradiation. Most of this difference resulted from the change in radiation quality, since the relative effectiveness of X- versus γ-irradiation was 1.9 at low and 1.6 at high dose rates. For each radiation, however, fewer dominant lethals were induced at low dose-rates than at high (low/high ratios of 0.8 and 0.9 respectively) although differences did not reach a significant level. There were no statistically significant effects of dose rate on testis-weight of sperm-count in the X-ray series, but there were significantly less severe effects on both with protraction of the γ-irradiation. Evidence for effects of radiation quality on these characters was conflicting. Frequencies of abnormal spermatozoa were markedly increased 7 weeks after irradiation but there were no consistent effects of radiation intensity or quality. (orig.)

Lethal and behavioral effects of pesticides on the insect predator Macrolophus pygmaeus.

Science.gov (United States)

Martinou, A F; Seraphides, N; Stavrinides, M C

2014-02-01

Macrolophus pygmaeus (Hemiptera: Miridae) is a common generalist predator in Mediterranean agro-ecosystems. We evaluated the lethal effects of six insecticides and a fungicide on M. pygmaeus nymphs exposed to the pesticides through three routes of exposure: direct, residual and oral. Chlorantraniliprole and emamectin-benzoate caused less than 25% mortality to M. pygmaeus and were classified as harmless according to the International Organization for Biological Control rating scheme. In contrast, thiacloprid and metaflumizone caused 100% and 80% mortality, respectively, and were classified as harmful. Indoxacarb and spinosad resulted in close to 30% mortality to the predator, and were classified as slightly harmful, while the fungicide copper hydroxide caused 58% mortality and was rated as moderately harmful. Chlorantraniliprole and thiacloprid were selected for further sublethal testing by exposing M. pygmaeus to two routes of pesticide intake: pesticide residues and feeding on sprayed food. Thiacloprid led to an increase in resting and preening time of the predator, and a decrease in plant feeding. Chlorantraniliprole resulted in a decrease in plant feeding, but no other behaviors were affected. In addition, thiacloprid significantly reduced the predation rate of M. pygmaeus, whereas chlorantraniliprole had no significant effect on predation rate. The results of the study suggest that thiacloprid is not compatible with M. pygmaeus, while further research needs to be carried out for metaflumizone and copper hydroxide. All other products seem to be relatively compatible with M. pygmaeus, though studies on their sublethal effects will shed more light into their safety. Copyright © 2013 Elsevier Ltd. All rights reserved.

Toxicity of selenite in the unicellular green alga Chlamydomonas reinhardtii: Comparison between effects at the population and sub-cellular level

International Nuclear Information System (INIS)

Morlon, Helene; Fortin, Claude; Floriani, Magali; Adam, Christelle; Garnier-Laplace, Jacqueline; Boudou, Alain

2005-01-01

The toxicity of selenium in aquatic ecosystems is mainly linked to its uptake and biotransformation by micro-organisms, and its subsequent transfer upwards into the food chain. Thus, organisms at low trophic level, such as algae, play a crucial role. The aim of our study was to investigate the biological effects of selenite on Chlamydomonas reinhardtii, both at the sub-cellular level (effect on ultrastructure) and at the population level (effect on growth). The cells were grown under batch culture conditions in well-defined media and exposed to waterborne selenite at concentrations up to 500 μM; i.e. up to lethal conditions. Based on the relationship between Se concentration and cell density achieved after a 96 h exposure period, an EC 50 of 80 μM with a 95% confidence interval ranging between 64 and 98 μM was derived. No adaptation mechanisms were observed: the same toxicity was quantified for algae pre-contaminated with Se. The inhibition of growth was linked to impairments observed at the sub-cellular level. The intensity of the ultrastructural damages caused by selenite exposure depended on the level and duration of exposure. Observations by TEM suggested chloroplasts as the first target of selenite cytotoxicity, with effects on the stroma, thylakoids and pyrenoids. At higher concentrations, we could observe an increase in the number and volume of starch grains. For cells collected at 96 h, electron-dense granules were observed. Energy-dispersive X-ray microanalysis revealed that these granules contained selenium and were also rich in calcium and phosphorus. This study confirms that the direct toxicity of selenite on the phytoplankton biomass is not likely to take place at concentrations found in the environment. At higher concentrations, the link between effects at the sub-cellular and population levels, the over-accumulation of starch, and the formation of dense granules containing selenium are reported for the first time in the literature for a

The relative biological effectiveness of fractionated doses of fast neutrons (42 MeV sub d yields Be ) for normal tissues. Pt. 3; Effects on lung function

Energy Technology Data Exchange (ETDEWEB)

Rezvani, M.; Hopewell, J.W.; Robbins, M.E.C.; Hamlet, R. (Churchill Hospital, Oxford (UK)); Barnes, D.W.H.; Sansom, J.M.; Adams, P.J.V. (Medical Research Council, Harwell (UK). Radiobiological Research Unit)

1990-11-01

The effect of single and fractionated doses of fast neutrons (42 MeV{sub d{yields}Bc}) on the early and late radiation responses of the pig lung have been assessed by the measurement of changes in lung function using a {sup 133}Xe washout technique. The results obtained for irradiation schedules with fast neutrons have been compared with those after photon irradiation. There was no statistically significant difference between the values for the relative biological effectiveness (RBE) for the early and late radiation response of the lung. The RBE of the neutron beam increased with decreasing size of dose/fraction with an upper limit value of 4.39 {plus minus} 0.94 for infinitely small X-ray doses per fraction. (author).

The lethal effect of longwave ultraviolet light and PUVA. An analysis based upon human mesenchymal cells in vitro

International Nuclear Information System (INIS)

Jongh, G. de; Bergers, M.; Boezeman, J.B.M.; Verhagen, A.R.; Mier, P.D.

1984-01-01

The lethal effect of UVA and PUVA radiation was studied in cultures of fresh and mature monocytes. UVA radiation alone was shown to possess a lethal effect at doses which are attained in the dermis in vivo. The synergistic action of 8-methoxypsoralen and UVA radiation predominated in PUVA radiation, but again a residual effect of UVA alone was demonstrated mathematically. Mature cells were less sensitive than fresh monocytes. The results indicate that a monolayer culture of non-dividing, mesenchymal cells offers considerable advantages over in vivo systems as a model for the study of phototoxicity. (author)

Suicide Lethality: A Concept Analysis.

Science.gov (United States)

DeBastiani, Summer; De Santis, Joseph P

2018-02-01

Suicide is a significant health problem internationally. Those who complete suicide may have different behaviors and risk factors than those who attempt a non-fatal suicide. The purpose of this article is to analyze the concept of suicide lethality and propose a clear definition of the concept through the identification of antecedents, attributes, and consequences. A literature search for articles published in the English language between 1970 and 2016 was conducted using MEDLINE, the Cochrane Library, Pubmed, Psychlit, Ovid, PsycINFO, and Proquest. The bibliographies of all included studies were also reviewed to identify additional relevant citations. A concept analysis was conducted on the literature findings using six stages of Walker and Avant's method. The concept analysis differentiated between suicide, lethality, suicidal behavior, and suicide lethality. Presence of a suicide plan or a written suicide note was not found to be associated with the majority of completed suicides included in the definition of suicide lethality. There are a few scales that measure the lethality of a suicide attempt, but none that attempt to measure the concept of suicide lethality as described in this analysis. Clarifying the concept of suicide lethality encourages awareness of the possibility of different suicidal behaviors associated with different suicide outcomes and will inform the development of future nursing interventions. A clearer definition of the concept of suicide lethality will guide clinical practice, research, and policy development aimed at suicide prevention.

Hematologic syndrome in man modeled from mammalian lethality

International Nuclear Information System (INIS)

Jones, T.D.

1981-01-01

Data on acute radiation lethality due to failure of the hematologic system in rats, mice, dogs, swine, monkeys and man are analyzed. Based on the available data, the mortality incidences for 1-100% levels can be computed directly if one has only an estimate of the dose lethal to 50% of the population (LD 50 ) for the mammalian strain and radiation environment of interest. The sole restriction is that the dose profile to the marrow be moderately uniform. If an LD 50 for any exposure situation has been measured, then one can readily scale to any desired situation through implicit-biological and empirical-physical relationships. The LD 50 for man, exposed to an isotropic cloud of photons, and knowledge of the bone-marrow dose profiles readily permit evaluation of the model for other levels of human mortality from different irradiating particles, partial body irradiation and spatially dependent and/or mixed radiation environments. (author)

Lethal effect of glucose load on malignant cells

International Nuclear Information System (INIS)

Shmakova, N.L.; Yarmonenko, S.P.; Kozubek, S.

1987-01-01

Ehrlich ascites tumor (EAT) cells were treated with glucose load under anoxic conditions (for 15 or 60 min) and/or with γ radiation (20 Gy). The efficiency of the treatment was judged from the tumorigenic activity of EAT cell inocula. The markedly increased efficiency of the combined treatment of EAT cells using glucose load in anoxia and γ radiation is due to the additive action of both agents. The glucose load in anoxia leads to extensive desintegration of tumor cells. Further, the lethal effect of various pH values on EAT cells was investigated. Different pH values were obtained by means of both glucose load and phosphate buffers. The effect was investigated by determining the tumorigenic activity of EAT cells tested in vivo in mice and by determining the radiosensitivity of treated EAT cells. The results allowed us to conclude that the same values of pH lead to the same effect on EAT cells independently of the way by which the given pH value was reached. (author). 5 figs., 2 tabs., 12 refs

Estimation of the contribution of ionization and excitation to the lethal effect of ionizing radiation

International Nuclear Information System (INIS)

Petin, V.G.; Komarov, V.P.

1982-01-01

A simple theoretical model is proposed for estimating the differential contribution of ionization and excitation to the lethal effect of ionizing radiation. Numerical results were obtained on the basis of published experimental data on the ability of bacterial cells Escherichia coli to undergo photoreactivation of radiation-induced damage. It was shown that inactivation by excitation may be highly significant for UV-hypersensitive cells capable of photoreactivation; inactivation by excitation increased with the energy of ionizing radiation and the volume of irradiated suspensions. The data are in qualitative agreement with the assumption of a possible contribution of the UV-component of Cerenkov radiation to the formation of excitations responsible for the lethal effect and the phenomenon of photoreactivation after ionizing radiation. Some predictions from the model are discussed. (orig.)

Genetic interaction motif finding by expectation maximization – a novel statistical model for inferring gene modules from synthetic lethality

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Ye Ping

2005-12-01

Full Text Available Abstract Background Synthetic lethality experiments identify pairs of genes with complementary function. More direct functional associations (for example greater probability of membership in a single protein complex may be inferred between genes that share synthetic lethal interaction partners than genes that are directly synthetic lethal. Probabilistic algorithms that identify gene modules based on motif discovery are highly appropriate for the analysis of synthetic lethal genetic interaction data and have great potential in integrative analysis of heterogeneous datasets. Results We have developed Genetic Interaction Motif Finding (GIMF, an algorithm for unsupervised motif discovery from synthetic lethal interaction data. Interaction motifs are characterized by position weight matrices and optimized through expectation maximization. Given a seed gene, GIMF performs a nonlinear transform on the input genetic interaction data and automatically assigns genes to the motif or non-motif category. We demonstrate the capacity to extract known and novel pathways for Saccharomyces cerevisiae (budding yeast. Annotations suggested for several uncharacterized genes are supported by recent experimental evidence. GIMF is efficient in computation, requires no training and automatically down-weights promiscuous genes with high degrees. Conclusion GIMF effectively identifies pathways from synthetic lethality data with several unique features. It is mostly suitable for building gene modules around seed genes. Optimal choice of one single model parameter allows construction of gene networks with different levels of confidence. The impact of hub genes the generic probabilistic framework of GIMF may be used to group other types of biological entities such as proteins based on stochastic motifs. Analysis of the strongest motifs discovered by the algorithm indicates that synthetic lethal interactions are depleted between genes within a motif, suggesting that synthetic

A Recombinant Adenovirus Expressing Ovine Interferon Tau Prevents Influenza Virus-Induced Lethality in Mice.

Science.gov (United States)

Martín, V; Pascual, E; Avia, M; Rangel, G; de Molina, A; Alejo, A; Sevilla, N

2016-01-06

Ovine interferon tau (IFN-τ) is a unique type I interferon with low toxicity and a broad host range in vivo. We report the generation of a nonreplicative recombinant adenovirus expressing biologically active IFN-τ. Using the B6.A2G-Mx1 mouse model, we showed that single-dose intranasal administration of recombinant Ad5-IFN-τ can effectively prevent lethality and disease induced by highly virulent hv-PR8 influenza virus by activating the interferon response and preventing viral replication. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Dominant lethal and ovarian effects of plutonium-239 in female mice

International Nuclear Information System (INIS)

Searle, A.G.; Beechey, C.V.; Green, D.; Howells, G.R.

1982-01-01

(C3H x 101)F 1 female mice were injected intravenously with 239 Pu in trisodium citrate, then mated in pairs to strain CBA males, to test for dominant lethality. In the first experiment 10μCi kg -1 and in the second 20μCi kg -1 body mass was injected. Matings were after 6 days in the first experiment (estimated ovarian absorbed dose of 0.1 Gy) and after 3,6 or 12 weeks in the second (estimated ovarian doses of 1.11, 2.45 and 5.91 Gy respectively). No evidence of dominant lethal induction was found in the first experiment, but in the second there was a significant increase over controls in pre-implantation loss in all three series. Post-implantation lethality increased significantly (by 12%) only after 12 weeks' exposure. With the 6- and 12-week exposures (especially the latter) luteal counts fell, fewer females becoming pregnant than in controls. This is attributed to oocyte killing by the α-particles. Histological and autoradiographic investigations showed a marked reduction in ovarian size and follicular numbers with fission-tracks clustered mainly over the medullary stroma. The preimplantation loss may stem from lowered fertilization of oocytes because of their damage, so that the best measure of dominant lethality is that based on post-implantation death. (author)

Effect of As/sub 2/O/sub 3/ on gluconeogenesis

Energy Technology Data Exchange (ETDEWEB)

Szinicz, L.; Forth, W.

1988-06-01

The effect of As/sub 2/O/sub 3/ and As/sub 2/O/sub 5/ on gluconeogenesis from various substrates in the liver and kidney of rats was investigated. A concentration-dependent inhibition by As/sub 2/O/sub 3/ was found. The highest degree of inhibition was observed in incubations with pyruvate. The inhibition of glucose formation was accompanied to a lesser extent by a diminution in O/sub 2/ consumption and ATP content. The effect was also dependent on the substrate used. Oleate, 0,5 mmol/l, increased gluconeogenesis from pyruvate. The effect was not abolished by As/sub 2/O/sub 3/. A decrease in the content of acetyl-CoA, 3-hydroxybutyrate, and reduced glutathione was found in suspensions of isolated rat kidney tubules or hepatocytes incubated with As/sub 2/O/sub 3/. About 10 times higher concentrations of As/sub 2/O/sub 5/ were necessary to induce a similar extent of inhibition of gluconeogenesis, decrease in O/sub 2/ consumption, and in ATP content as compared with As/sub 2/O/sub 3/. Gluconeogenesis from pyruvate exhibited highest sensitivity to As/sub 2/O/sub 5/. Starved rats were shown to be much more sensitive to As/sub 2/O/sub 3/ than animals with free access to food.

Inhibition of light modulation of chloroplast enzyme activity by sulfite. One of the lethal effects of SO/sub 2/

Energy Technology Data Exchange (ETDEWEB)

Anderson, L E; Duggan, J X

1977-01-01

The capacity of a particulate pea (Pisum sativum L.) leaf chloroplast system for light-modulation of enzyme activity is diminished by brief exposure to sodium sulfite and, when intact seedlings are exposed to atmospheric SO/sub 2/, the same system is inactivated. The destructive effect of this pollutant on green plants may therefore be due to disruption of the mechanism for control of carbon dioxide fixation.

Effects of salinity on short-term waterborne zinc uptake, accumulation and sub-lethal toxicity in the green shore crab (Carcinus maenas)

International Nuclear Information System (INIS)

Niyogi, Som; Blewett, Tamzin A.; Gallagher, Trevor; Fehsenfeld, Sandra; Wood, Chris M.

2016-01-01

Highlights: • Zinc accumulation in the euryhaline green crab is partially salinity dependent. • Zinc accumulates mainly in the gills of green crab during acute waterborne exposure. • Branchial zinc and calcium transport in the green crab occurs via a common pathway. • Acute waterborne Zn exposure disrupts calcium and zinc homeostasis in the green crab. - Abstract: Waterborne zinc (Zn) is known to cause toxicity to freshwater animals primarily by disrupting calcium (Ca) homeostasis during acute exposure, but its effects in marine and estuarine animals are not well characterized. The present study investigated the effects of salinity on short-term Zn accumulation and sub-lethal toxicity in the euryhaline green shore crab, Carcinus maenas. The kinetic and pharmacological properties of short-term branchial Zn uptake were also examined. Green crabs (n = 10) were exposed to control (no added Zn) and 50 μM (3.25 mg L"−"1) of waterborne Zn (∼25% of 96 h LC_5_0 in 100 seawater) for 96 h at 3 different salinity regimes (100%, 60% and 20% seawater). Exposure to waterborne Zn increased tissue-specific Zn accumulation across different salinities. However, the maximum accumulation occurred in 20% seawater and no difference was recorded between 60% and 100% seawater. Gills appeared to be the primary site of Zn accumulation, since the accumulation was significantly higher in the gills relative to the hepatopancreas, haemolymph and muscle. Waterborne Zn exposure induced a slight increase in haemolymph osmolality and chloride levels irrespective of salinity. In contrast, Zn exposure elicited marked increases in both haemolymph and gill Ca levels, and these changes were more pronounced in 20% seawater relative to that in 60% or 100% seawater. An in vitro gill perfusion technique was used to examine the characteristics of short-term (1–4 h) branchial Zn uptake over an exposure concentration range of 3–12 μM (200–800 μg L"−"1). The rate of short-term branchial Zn

Gene expression profiling of prostate tissue identifies chromatin regulation as a potential link between obesity and lethal prostate cancer.

Science.gov (United States)

Ebot, Ericka M; Gerke, Travis; Labbé, David P; Sinnott, Jennifer A; Zadra, Giorgia; Rider, Jennifer R; Tyekucheva, Svitlana; Wilson, Kathryn M; Kelly, Rachel S; Shui, Irene M; Loda, Massimo; Kantoff, Philip W; Finn, Stephen; Vander Heiden, Matthew G; Brown, Myles; Giovannucci, Edward L; Mucci, Lorelei A

2017-11-01

Obese men are at higher risk of advanced prostate cancer and cancer-specific mortality; however, the biology underlying this association remains unclear. This study examined gene expression profiles of prostate tissue to identify biological processes differentially expressed by obesity status and lethal prostate cancer. Gene expression profiling was performed on tumor (n = 402) and adjacent normal (n = 200) prostate tissue from participants in 2 prospective cohorts who had been diagnosed with prostate cancer from 1982 to 2005. Body mass index (BMI) was calculated from the questionnaire immediately preceding cancer diagnosis. Men were followed for metastases or prostate cancer-specific death (lethal disease) through 2011. Gene Ontology biological processes differentially expressed by BMI were identified using gene set enrichment analysis. Pathway scores were computed by averaging the signal intensities of member genes. Odds ratios (ORs) for lethal prostate cancer were estimated with logistic regression. Among 402 men, 48% were healthy weight, 31% were overweight, and 21% were very overweight/obese. Fifteen gene sets were enriched in tumor tissue, but not normal tissue, of very overweight/obese men versus healthy-weight men; 5 of these were related to chromatin modification and remodeling (false-discovery rate 7, 41% vs 17%; P = 2 × 10 -4 ) and an increased risk of lethal disease that was independent of grade and stage (OR, 5.26; 95% confidence interval, 2.37-12.25). This study improves our understanding of the biology of aggressive prostate cancer and identifies a potential mechanistic link between obesity and prostate cancer death that warrants further study. Cancer 2017;123:4130-4138. © 2017 American Cancer Society. © 2017 American Cancer Society.

Induction of lethal and genetic damage by vacuum-ultraviolet (163 nm) irradiation of aqueous suspensions of yeast cells

International Nuclear Information System (INIS)

Ito, T.; Kobayashi, K.

1976-01-01

Yeast cells suspended in distilled water were irradiated with monochromatic 163 nm photons by immersing a specially designed discharge tube into the suspension. This was thought to be a useful means of investigating in vivo effects of radiation-induced water radicals on well cells in the complete absence of ionic species, since 163 nm photons can dissociate water only via excitation. These experiments showed that the water radicals (excluding e/sub aq/ - ) exerted both lethal and genetic (gene-conversion) effects quite potently, and the characteristic protection against these effects was observable when 2-mercaptoethanol or, in particular, p-aminobenzoic acid, a specific scavenger for OH radicals, was added to the medium prior to irradiation. Nearly complete protection from both lethal and genetic effects was observed in some cases with p-aminobenzoic acid. These results establish unequivocally that the OH radical, and not the hydrogen atom (H radical), possesses the damaging potency in the cell. Comparisons with γ-ray experiments revealed several differences between 163 nm photons and γ rays in the protective actions of radical scavengers, which may be attributable to reactive species other than OH radicals produced by the γ rays

Effects of copper on invertebrate–sediment interactions

International Nuclear Information System (INIS)

Hunting, E.R.; Mulder, C.; Kraak, M.H.S.; Breure, A.M.; Admiraal, W.

2013-01-01

Toxicants potentially decouple links between biodiversity and ecosystem processes. This study aimed to evaluate how toxicants affect invertebrate bioturbation and decomposition. Effects of copper on functionally distinct macrofaunal species (Asellus aquaticus and Tubifex spp.), decomposition (release of dissolved organic carbon, DOC) and Average Metabolic Response (AMR) and Community Metabolic Diversity (CMD) of bacteria were determined in 5-day microcosm experiments. Bioturbation was assessed as sediment redox potential (Eh) profiles. Concentration–response curves of the functional parameters DOC, and the faunal mediated AMR and CMD in the presence of Tubifex spp. depended on Tubifex spp. survival, i.e. similar EC 50 values for both endpoints. In contrast, functional parameters in the presence of A. aquaticus were more sensitive than survival. Sediment Eh-profiles showed that reduced decomposition was caused by reduced sediment reworking by A. aquaticus at sub-lethal copper concentrations. These observations hint at a decoupling of invertebrate community structure and ecosystem functioning upon stress. -- Highlights: •We compared invertebrate survival and functional responses to copper amendment. •Differential functional responses depending on invertebrate species. •Reduced functional responses with A. aquaticus at sub-lethal copper concentrations. •Sub-lethal copper concentrations reduced the bioturbating activities of A. aquaticus. •Stress decouples invertebrate community structure and ecosystem functioning. -- Sub-lethal copper concentrations reduced the bioturbating activities of A. aquaticus and invertebrate effects on decomposition, bacterial activity and community metabolic diversity

[Lethal effect after transmutation of 33P incorporated into bacteriophage S 13 and mechanisms of DNA double helix rupture].

Science.gov (United States)

Apelgot, S

1980-04-01

The experiments show the lethal effect of the beta decay of 33P incorporated in DNA of bacteriophage S 13. The lethal efficiency is high, 0.72 at 0 degrees C and 0.55 at--197 degrees C. The presence of a radical scavenger like AET has no influence. It was found previously that for such phages with single-stranded DNA, the lethal efficiency of 32P decay is unity, and that the lethal event is a DNA single-strand break, owing to the high energy of the nucleogenic 32S atom. As the recoil energy of the 33S atom is too low to account for such a break, it is suggested that the reorganization of the phosphate molecule into sulphate is able to bring about a DNA single-strand break with an efficiency as high as 0.7, at 0 degrees C. A model for the DNA double-strand-break produced by a transmutation processes is suggested.

Differential replication of foot-and-mouth disease viruses in mice determine lethality

Science.gov (United States)

Adult C57BL/6J mice have been used to study foot-and-mouth disease virus (FMDV) biology. In this work, two variants of an FMDV A/Arg/01 strain exhibiting differential pathogenicity in adult mice were identified and characterized: a non-lethal virus (A01NL) caused mild signs of disease, whereas a let...

Mammalian cell biology

International Nuclear Information System (INIS)

Elkind, M.M.

1979-01-01

This section contains summaries of research on mechanisms of lethality and radioinduced changes in mammalian cell properties, new cell systems for the study of the biology of mutation and neoplastic transformation, and comparative properties of ionizing radiations

Biological radiation effects of Radon in Drosophila

International Nuclear Information System (INIS)

Pimentel P, A.E.

1995-01-01

In order to contribute to the knowledge on the effects of radon and its decay products, the aim of this investigation is to study the biological effects of radon using Drosophila melanogaster throught the somatic mutation and recombination test (SMART) and the analysis of some adaptative factors exposing larvaes to controlled radon atmosphers, considering that this insect could be used as biological monitor. Using the somatic mutation test a mutagenic effect was observed proportional to radon concentration, into an interval of 1 ± 0.3 to 111 ± 7.4 KBq/m 3 equivalent to doses under 0.0106 Gy. The correlation analysis gives a linear (r=0.80) relationship with a positive slope of 0.2217. The same happens when gamma rays are used in the interval of 1 to 20 Gy, given a linear dose-dependent effect (r=0.878) is obtained; nevetheless the slop is smaller (m=0.003) than for radon. Analysing the results of adaptative factors of the nine exposed generations, it was found that probably radon exposition induced dominant lethals during gametogenesis or/and a selection of the more component gamets of the treated individuals in larval state. It was reflected in the significant decrease on fecundity of the generation exposed. Nevertheless the laying eggs had an increase in egg-to-adult viability and the develop velocity was higher than in control for 3 KBq/m 3 , this suggest that radon concentrations used were able to induce repair mechanisms. These data agree with the Hormesis hypothesis that says: low doses have positive effects on health. It was not possible to obtain a dose-effect relationship except with the develop velocity where it was found a dose-effect inverse proportion. In conclusion, Drosophila melanogaster could be a good system to obtain in vivo damaged induction concentration dependent of radon and its decay products, as well as to study the effects in an exposed population by the analysis of adaptative factors. (Author)

Exchange-bias-like effect in Pr{sub 0.75}Tb{sub 0.25}Al{sub 2} and Pr{sub 0.7}Tb{sub 0.3}Al{sub 2} samples

Energy Technology Data Exchange (ETDEWEB)

Tedesco, J.C.G., E-mail: tedesco.jcg@gmail.com [Instituto de Física “Gleb Wataghin”, Universidade Estadual de Campinas—UNICAMP, 13083-859 Campinas, SP (Brazil); Pires, M.J.M. [Instituto de Ciência e Tecnologia—ICT, Universidade Federal dos Vales do Jequitinhonha e Mucuri—UFVJM, 39100-000 Diamantina, MG (Brazil); Carvalho, A. Magnus G. [Divisão de Metrologia de Materiais (DIMAT), INMETRO, 25250-020 Duque de Caxias, RJ (Brazil); Sousa, V.S.R. de [Instituto de Física “Armando Dias Tavares”, Universidade do Estado do Rio de Janeiro—UERJ, 20550-013 Rio de Janeiro, RJ (Brazil); Cardoso, L.P.; Coelho, A.A. [Instituto de Física “Gleb Wataghin”, Universidade Estadual de Campinas—UNICAMP, 13083-859 Campinas, SP (Brazil)

2013-08-15

The magnetic behavior of pseudobinary Pr{sub 0.7}Tb{sub 0.3}Al{sub 2} and Pr{sub 0.75}Tb{sub 0.25}Al{sub 2} compounds was studied, and a predominant ferrimagnetic ordering was observed. Noteworthy characteristics such as negative magnetization, compensation points and exchange-bias-like (EB-like) effect were found. This EB-like effect was observed at temperatures below the compensation points. The effect is somewhat different from the one already studied in similar systems combining light and heavy rare earths. The results indicate that the EB-like effect characteristics are related to the conduction electron magnetic polarization and an induced unidirectional anisotropy present in these compounds. - Highlights: ► Ferrimagnetic behavior is observed in Pr{sub 0.7}Tb{sub 0.3}Al{sub 2} and Pr{sub 0.75}Tb{sub 0.25}Al{sub 2} materials. ► Magnetic data indicate a strong unidirectional anisotropy in studied materials. ► Studied materials present the exchange-bias-like effect. ► Exchange-bias-like effect explained in analogy with the known mechanism of thin films.

Nanogranular SiO{sub 2} proton gated silicon layer transistor mimicking biological synapses

Energy Technology Data Exchange (ETDEWEB)

Liu, M. J.; Huang, G. S., E-mail: gshuang@fudan.edu.cn, E-mail: pfeng@nju.edu.cn; Guo, Q. L.; Tian, Z. A.; Li, G. J.; Mei, Y. F. [Department of Materials Science, Fudan University, Shanghai 200433 (China); Feng, P., E-mail: gshuang@fudan.edu.cn, E-mail: pfeng@nju.edu.cn; Shao, F.; Wan, Q. [School of Electronic Science and Engineering and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China)

2016-06-20

Silicon on insulator (SOI)-based transistors gated by nanogranular SiO{sub 2} proton conducting electrolytes were fabricated to mimic synapse behaviors. This SOI-based device has both top proton gate and bottom buried oxide gate. Electrical transfer properties of top proton gate show hysteresis curves different from those of bottom gate, and therefore, excitatory post-synaptic current and paired pulse facilitation (PPF) behavior of biological synapses are mimicked. Moreover, we noticed that PPF index can be effectively tuned by the spike interval applied on the top proton gate. Synaptic behaviors and functions, like short-term memory, and its properties are also experimentally demonstrated in our device. Such SOI-based electronic synapses are promising for building neuromorphic systems.

Differential antagonism of tetramethylenedisulfotetramine-induced seizures by agents acting at NMDA and GABA{sub A} receptors

Energy Technology Data Exchange (ETDEWEB)

Shakarjian, Michael P., E-mail: michael_shakarjian@nymc.edu [Department of Environmental Health Science, School of Health Sciences and Practice, Institute of Public Health, New York Medical College, Valhalla, NY, 10595 (United States); Department of Medicine, Division of Pulmonary and Critical Care Medicine, UMDNJ–Robert Wood Johnson Medical School, Piscataway, NJ 08854 (United States); Velíšková, Jana [Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY 10595 (United States); Department of Obstetrics and Gynecology, New York Medical College, Valhalla, NY 10595 (United States); Department of Neurology, New York Medical College, Valhalla, NY 10595 (United States); Stanton, Patric K., E-mail: patric_stanton@nymc.edu [Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY 10595 (United States); Department of Neurology, New York Medical College, Valhalla, NY 10595 (United States); Velíšek, Libor [Department of Cell Biology and Anatomy, New York Medical College, Valhalla, NY 10595 (United States); Department of Neurology, New York Medical College, Valhalla, NY 10595 (United States); Department of Pediatrics, New York Medical College, Valhalla, NY 10595 (United States)

2012-11-15

Tetramethylenedisulfotetramine (TMDT) is a highly lethal neuroactive rodenticide responsible for many accidental and intentional poisonings in mainland China. Ease of synthesis, water solubility, potency, and difficulty to treat make TMDT a potential weapon for terrorist activity. We characterized TMDT-induced convulsions and mortality in male C57BL/6 mice. TMDT (ip) produced a continuum of twitches, clonic, and tonic–clonic seizures decreasing in onset latency and increasing in severity with increasing dose; 0.4 mg/kg was 100% lethal. The NMDA antagonist, ketamine (35 mg/kg) injected ip immediately after the first TMDT-induced seizure, did not change number of tonic–clonic seizures or lethality, but increased the number of clonic seizures. Doubling the ketamine dose decreased tonic–clonic seizures and eliminated lethality through a 60 min observation period. Treating mice with another NMDA antagonist, MK-801, 0.5 or 1 mg/kg ip, showed similar effects as low and high doses of ketamine, respectively, and prevented lethality, converting status epilepticus EEG activity to isolated interictal discharges. Treatment with these agents 15 min prior to TMDT administration did not increase their effectiveness. Post-treatment with the GABA{sub A} receptor allosteric enhancer diazepam (5 mg/kg) greatly reduced seizure manifestations and prevented lethality 60 min post-TMDT, but ictal events were evident in EEG recordings and, hours post-treatment, mice experienced status epilepticus and died. Thus, TMDT is a highly potent and lethal convulsant for which single-dose benzodiazepine treatment is inadequate in managing electrographic seizures or lethality. Repeated benzodiazepine dosing or combined application of benzodiazepines and NMDA receptor antagonists is more likely to be effective in treating TMDT poisoning. -- Highlights: ► TMDT produces convulsions and lethality at low doses in mice. ► Diazepam pre- or post-treatments inhibit TMDT-induced convulsions and death

Mutagenesis-mediated virus extinction: virus-dependent effect of viral load on sensitivity to lethal defection.

Directory of Open Access Journals (Sweden)

Héctor Moreno

Full Text Available BACKGROUND: Lethal mutagenesis is a transition towards virus extinction mediated by enhanced mutation rates during viral genome replication, and it is currently under investigation as a potential new antiviral strategy. Viral load and virus fitness are known to influence virus extinction. Here we examine the effect or the multiplicity of infection (MOI on progeny production of several RNA viruses under enhanced mutagenesis. RESULTS: The effect of the mutagenic base analogue 5-fluorouracil (FU on the replication of the arenavirus lymphocytic choriomeningitis virus (LCMV can result either in inhibition of progeny production and virus extinction in infections carried out at low multiplicity of infection (MOI, or in a moderate titer decrease without extinction at high MOI. The effect of the MOI is similar for LCMV and vesicular stomatitis virus (VSV, but minimal or absent for the picornaviruses foot-and-mouth disease virus (FMDV and encephalomyocarditis virus (EMCV. The increase in mutation frequency and Shannon entropy (mutant spectrum complexity as a result of virus passage in the presence of FU was more accentuated at low MOI for LCMV and VSV, and at high MOI for FMDV and EMCV. We present an extension of the lethal defection model that agrees with the experimental results. CONCLUSIONS: (i Low infecting load favoured the extinction of negative strand viruses, LCMV or VSV, with an increase of mutant spectrum complexity. (ii This behaviour is not observed in RNA positive strand viruses, FMDV or EMCV. (iii The accumulation of defector genomes may underlie the MOI-dependent behaviour. (iv LCMV coinfections are allowed but superinfection is strongly restricted in BHK-21 cells. (v The dissimilar effects of the MOI on the efficiency of mutagenic-based extinction of different RNA viruses can have implications for the design of antiviral protocols based on lethal mutagenesis, presently under development.

Quantification and Purification of Mangiferin from Chinese Mango (Mangifera indica L. Cultivars and Its Protective Effect on Human Umbilical Vein Endothelial Cells under H<sub>2sub>O>2sub>-induced Stress

Directory of Open Access Journals (Sweden)

Kunsong Chen

2012-09-01

Full Text Available Mangiferin is a natural xanthonoid with various biological activities. Quantification of mangiferin in fruit peel, pulp, and seed kernel was carried out in 11 Chinese mango (Mangifera indica L. cultivars. The highest mangiferin content was found in the peel of Lvpimang (LPM fruit (7.49 mg/g DW. Efficient purification of mangiferin from mango fruit peel was then established for the first time by combination of macroporous HPD100 resin chromatography with optimized high-speed counter-current chromatography (HSCCC. Purified mangiferin was identified by both HPLC and LC-MS, and it showed higher DPPH^• free-radical scavenging capacities and ferric reducing ability of plasma (FRAP than by l-ascorbic acid (Vc or Trolox. In addition, it showed significant protective effects on human umbilical vein endothelial cells (HUVEC under H<sub>2sub>O>2sub>-induced stress. Cells treated with mangiferin resulted in significant enhanced cell survival under of H<sub>2sub>O>2sub> stress. Therefore, mangiferin from mango fruit provides a promising perspective for the prevention of oxidative stress-associated diseases.

Biological effects of deuterium - depleted water

International Nuclear Information System (INIS)

Stefanescu, I.; Titescu, Gh.; Croitoru, Cornelia; Saros-Rogobete, Irina

2000-01-01

Deuterium-depleted water (DDW) is represented by water that has an isotopic content smaller than 145 ppm D/(D + H). DDW production technique consists in the separation of deuterium from water by a continuous distillation process under pressure of about 133.3 mbar. The water used as raw material has a isotopic content of 145 ppm D/(D + H) and can be demineralized water, distillated water or condensed-steam. DDW results as a distillate with an isotopic deuterium content of 15-80 ppm, depending on the level we want to achieve. Beginning with 1996 the Institute of Cryogenics and Isotopic Technologies, DDW producer, co-operated with Romanian specialized institutes for studying the biological effects of DDW. The role of naturally occurring D in living organisms was examined by using DDW instead of natural water. These investigations led to the following conclusions: - DDW caused a tendency towards the increase of the basal tone, accompanied by the intensification of the vasoconstrictor effects of phenylefrine, noradrenaline and angiotensin; the increase of the basal tone and vascular reactivity produced by the DDW persists after the removal of the vascular endothelium; - Animals treated with DDW showed an increase of the resistance both to sublethal and lethal gamma radiation doses, suggesting a radioprotective action by the stimulation of non-specific immune defense mechanisms; - DDW stimulates immuno-defense reactions represented by the opsonic, bactericidal and phagocyte capacity of the immune system together with an increase in the number of poly-morphonuclear neutrophils; - Investigations regarding artificial reproduction of fish with DDW fecundated solutions confirmed favorable influence in embryo growth stage and resistance and following growth stages; - It was studied germination, growth and quantitative character variability in plants; one can remark the favorable influence of DDW on biological processes in plants in various ontogenetic stages. (authors)

Biological effects of radiation

International Nuclear Information System (INIS)

2013-01-01

This fourth chapter presents: cell structure and metabolism; radiation interaction with biological tissues; steps of the production of biological effect of radiation; radiosensitivity of tissues; classification of biological effects; reversibility, transmissivity and influence factors; pre-natal biological effects; biological effects in therapy and syndrome of acute irradiation

Antimicrobial activity of eumelanin-based hybrids: The role of TiO{sub 2} in modulating the structure and biological performance

Energy Technology Data Exchange (ETDEWEB)

Vitiello, Giuseppe [Department of Chemical, Materials and Production Engineering, University of Naples “Federico II”, p.le V. Tecchio 80, 80125 Naples (Italy); CSGI, Consorzio Interuniversitario per lo Sviluppo dei Sistemi a Grande Interfase, Via della Lastruccia 3, 50019 Florence (Italy); Pezzella, Alessandro [Department of Chemical Sciences, University of Naples “Federico II” via Cintia 4, 80126 Naples (Italy); Institute for Polymers, Composites and Biomaterials (IPCB), CNR, Via Campi Flegrei 34, 80078 Pozzuoli (Italy); Zanfardino, Anna [Department of Biology, University of Naples “Federico II” via Cintia 4, 80126 Naples (Italy); Silvestri, Brigida [Department of Chemical, Materials and Production Engineering, University of Naples “Federico II”, p.le V. Tecchio 80, 80125 Naples (Italy); Giudicianni, Paola [Istituto di Ricerche sulla Combustione, Centro Nazionale delle Ricerche IRC-CNR, via Claudio, 80125 Napoli (Italy); Costantini, Aniello [Department of Chemical, Materials and Production Engineering, University of Naples “Federico II”, p.le V. Tecchio 80, 80125 Naples (Italy); Varcamonti, Mario [Department of Biology, University of Naples “Federico II” via Cintia 4, 80126 Naples (Italy); Branda, Francesco [Department of Chemical, Materials and Production Engineering, University of Naples “Federico II”, p.le V. Tecchio 80, 80125 Naples (Italy); Luciani, Giuseppina, E-mail: giuseppina.luciani@unina.it [Department of Chemical, Materials and Production Engineering, University of Naples “Federico II”, p.le V. Tecchio 80, 80125 Naples (Italy)

2017-06-01

Eco-friendly hybrid Eumelanin-TiO{sub 2} nanostructures, recently obtained through in situ methodology based on hydrothermal route, have shown a striking antimicrobial activity, after exposure to oxidative environment, even under visible light induction condition. Nevertheless, the role of each component in defining the efficacy of these biological properties is far from being clearly defined. Furthermore, the effect of oxidative step on hybrids structure has not yet addressed. This study aims at elucidating the role of the ratio between eumelanin precursor, 5,6-dihydroxyindole-2-carboxylic acid (DHICA), and TiO{sub 2}, for its polymerization in defining morphology and structural organization of TiO{sub 2}-melanin nanostructures. Furthermore, tests on a Gram-negative Escherichia coli DH5α strain under UV irradiation and even visible light allowed to assess the contribution of each component, as well as of the TiO{sub 2}–DHICA charge transfer complex to overall biological performance. Finally, results of biocide characterization were combined with spectroscopic evidences to prove that oxidative treatment induces a marked structural modification in melanin thus enhancing overall antimicrobial efficacy. - Highlights: • Eco-friendly hybrid Eumelanin-TiO{sub 2} nanostructures shows striking antimicrobial activity under visible light. • TiO{sub 2} catalyzes 5,6-dihydroxyindole-2-carboxylic acid (DHICA) polymerization to eumelanin. • Eumelanin precursor/catalyst ratio modulates physico-chemical and structural properties of hybrid nanostructures. • Oxidative treatment increases the reticulation grade of the polymeric chains within the nanoparticles. • Additional oxidative process of the eumelanin pigment strongly improves the antimicrobial activity of hybrids.

Effect of salinity on the upper lethal temperature tolerance of early-juvenile red drum.

Science.gov (United States)

McDonald, Dusty; Bumguardner, Britt; Cason, Paul

2015-10-01

Previous work investigating the temperature tolerance of juvenile red drum ranging 18-50mm TL found evidence for positive size dependence (smaller fish less tolerant to higher temperatures) suggesting smaller size classes (temperatures. Here, we explored the upper lethal temperature tolerance (ULT) in smaller-sized red drum which ranged from 10 to 20mm TL across multiple salinities to further understand the thermal limitations of this propagated game fish. In order to investigate the combined effect of temperature and salinity on ULT, temperature trials were conducted under three levels of salinity which commonly occur along the coast of Texas (25, 35, and 45ppt). The rate of temperature increase (+0.25°C/h) was designed to mimic a natural temperature increase of a summer day in Texas. We determined that the lethal temperature at 50% (LT50) did not differ between the three salinities examined statistically; median lethal temperature for individuals exposed to 25ppt ranged from 36.4 to 37.7°C, 35ppt ranged from 36.4 to 37.7°C, and 45ppt ranged from 36.1 to 37.4°C. Further, LT50 data obtained here for early-juvenile red drum did not differ from data of a similar experiment examining 25mm TL sized fish. Published by Elsevier Ltd.

Influence of temperature and pressure on the lethality of ultrasound

International Nuclear Information System (INIS)

Raso, J.; Pagan, R.; Condon, S.; Sala, F.J.

1998-01-01

A specially designed resistometer was constructed, and the lethal effect on Yersinia enterocolitica of ultrasonic waves (UW) at different static pressures (manosonication [MS]) and of combined heat-UW under pressure treatments (manothermosonication [MTS]) was investigated. During MS treatments at 30 degrees C and 200 kPa, the increase in the amplitude of UW of 20 kHz from 21 to 150 micrometers exponentially decreased decimal reduction time values (D(MS)) from 4 to 0.37 min. When pressure was increased from 0 to 600 kPa at a constant amplitude (150 micrometers) and temperature (30 degrees C), D(MS) values decreased from 1.52 to 0.20 min. The magnitude of this decrease in D(MS) declined progressively as pressure was increased. The influence of pressure on D(MS) values was greater with increased amplitude of UW. Pressure alone of as much as 600 kPa did not influence the heat resistance of Y. enterocolitica (D60 = 0.094; zeta = 5.65). At temperatures of as much as 58 degrees C, the lethality of UW under pressure was greater than that of heat treatment alone at the same temperature. At higher temperatures, this difference disappeared. Heat and UW under pressure seemed to act independently. The lethality of MTS treatments appeared to result from the added effects of UW under pressure and the lethal effect of heat. The individual contributions of heat and of UW under pressure to the total lethal effect of MTS depended on temperature. The inactivating effect of UW was not due to titanium particles eroded from the sonication horn. The addition to the MS media of cysteamine did not increase the resistance of Y. enterocolitica to MS treatment. MS treatment caused cell disruption

A multivariate model of stakeholder preference for lethal cat management.

Science.gov (United States)

Wald, Dara M; Jacobson, Susan K

2014-01-01

Identifying stakeholder beliefs and attitudes is critical for resolving management conflicts. Debate over outdoor cat management is often described as a conflict between two groups, environmental advocates and animal welfare advocates, but little is known about the variables predicting differences among these critical stakeholder groups. We administered a mail survey to randomly selected stakeholders representing both of these groups (n=1,596) in Florida, where contention over the management of outdoor cats has been widespread. We used a structural equation model to evaluate stakeholder intention to support non-lethal management. The cognitive hierarchy model predicted that values influenced beliefs, which predicted general and specific attitudes, which in turn, influenced behavioral intentions. We posited that specific attitudes would mediate the effect of general attitudes, beliefs, and values on management support. Model fit statistics suggested that the final model fit the data well (CFI=0.94, RMSEA=0.062). The final model explained 74% of the variance in management support, and positive attitudes toward lethal management (humaneness) had the largest direct effect on management support. Specific attitudes toward lethal management and general attitudes toward outdoor cats mediated the relationship between positive (pstakeholder intention to support non-lethal cat management. Our findings suggest that stakeholders can simultaneously perceive both positive and negative beliefs about outdoor cats, which influence attitudes toward and support for non-lethal management.

The relative biological effectiveness (RBE) of high-energy electrons, x-rays and Co-60 gamma-rays

International Nuclear Information System (INIS)

Kiyono, Kunihiro

1974-01-01

Linac (Mitsubishi-Shimizu 15 MeV medical linear accelerator) electron beams with actual generated energies of 8, 10, 12 and 15 MeV were compared with X-ray beams having energies of 8 and 10 MV. The RBE values were calculated from 50 percent hatch-ability (LD 50 ) in silk-worm embryos, 30-days lethality (LDsub(50/30)) in ddY mice, and mean lethal dose (Do) in cultured mouse YL cells or human FL cells. To estimate the RBE in clinical experiments, LRD (leukocyte reduction dose) value was calculated for each patient irradiated on the chest or lumbar vertebrae. It was concluded that there is little difference in practical significance between 8 to 10 MV X-rays and 8 to 15 MeV electrons, and that the biological effects of Linac radiations are about 90 to 100 percent of the effect of 60 Co gamma rays. The RBE values gradually decreased, contrary to the elevation of energy between 8 and 15 MeV for electrons and between 8 and 10 MV for X-rays. These values were compared with those of earlier reviews of work in this field, and were briefly discussed. (Evans, J.)

How Close is too Close? The Effect of a Non-Lethal Electric Shark Deterrent on White Shark Behaviour.

Science.gov (United States)

Kempster, Ryan M; Egeberg, Channing A; Hart, Nathan S; Ryan, Laura; Chapuis, Lucille; Kerr, Caroline C; Schmidt, Carl; Huveneers, Charlie; Gennari, Enrico; Yopak, Kara E; Meeuwig, Jessica J; Collin, Shaun P

2016-01-01

Sharks play a vital role in the health of marine ecosystems, but the potential threat that sharks pose to humans is a reminder of our vulnerability when entering the ocean. Personal shark deterrents are being marketed as the solution to mitigate the threat that sharks pose. However, the effectiveness claims of many personal deterrents are based on our knowledge of shark sensory biology rather than robust testing of the devices themselves, as most have not been subjected to independent scientific studies. Therefore, there is a clear need for thorough testing of commercially available shark deterrents to provide the public with recommendations of their effectiveness. Using a modified stereo-camera system, we quantified behavioural interactions between white sharks (Carcharodon carcharias) and a baited target in the presence of a commercially available, personal electric shark deterrent (Shark Shield Freedom7™). The stereo-camera system enabled an accurate assessment of the behavioural responses of C. carcharias when encountering a non-lethal electric field many times stronger than what they would naturally experience. Upon their first observed encounter, all C. carcharias were repelled at a mean (± std. error) proximity of 131 (± 10.3) cm, which corresponded to a mean voltage gradient of 9.7 (± 0.9) V/m. With each subsequent encounter, their proximity decreased by an average of 11.6 cm, which corresponded to an increase in tolerance to the electric field by an average of 2.6 (± 0.5) V/m per encounter. Despite the increase in tolerance, sharks continued to be deterred from interacting for the duration of each trial when in the presence of an active Shark Shield™. Furthermore, the findings provide no support to the theory that electric deterrents attract sharks. The results of this study provide quantitative evidence of the effectiveness of a non-lethal electric shark deterrent, its influence on the behaviour of C. carcharias, and an accurate method for testing

How Close is too Close? The Effect of a Non-Lethal Electric Shark Deterrent on White Shark Behaviour.

Directory of Open Access Journals (Sweden)

Ryan M Kempster

Full Text Available Sharks play a vital role in the health of marine ecosystems, but the potential threat that sharks pose to humans is a reminder of our vulnerability when entering the ocean. Personal shark deterrents are being marketed as the solution to mitigate the threat that sharks pose. However, the effectiveness claims of many personal deterrents are based on our knowledge of shark sensory biology rather than robust testing of the devices themselves, as most have not been subjected to independent scientific studies. Therefore, there is a clear need for thorough testing of commercially available shark deterrents to provide the public with recommendations of their effectiveness. Using a modified stereo-camera system, we quantified behavioural interactions between white sharks (Carcharodon carcharias and a baited target in the presence of a commercially available, personal electric shark deterrent (Shark Shield Freedom7™. The stereo-camera system enabled an accurate assessment of the behavioural responses of C. carcharias when encountering a non-lethal electric field many times stronger than what they would naturally experience. Upon their first observed encounter, all C. carcharias were repelled at a mean (± std. error proximity of 131 (± 10.3 cm, which corresponded to a mean voltage gradient of 9.7 (± 0.9 V/m. With each subsequent encounter, their proximity decreased by an average of 11.6 cm, which corresponded to an increase in tolerance to the electric field by an average of 2.6 (± 0.5 V/m per encounter. Despite the increase in tolerance, sharks continued to be deterred from interacting for the duration of each trial when in the presence of an active Shark Shield™. Furthermore, the findings provide no support to the theory that electric deterrents attract sharks. The results of this study provide quantitative evidence of the effectiveness of a non-lethal electric shark deterrent, its influence on the behaviour of C. carcharias, and an accurate

Effects of sub-lethal levels of dichlorodiphenyltrichloroethane and dichlorodiphenyldichloroethylene on in vitro steroid biosynthesis by ovarian follicles or steroid metabolism by embryos of rainbow trout (Oncorhynchus mykiss)

International Nuclear Information System (INIS)

Petkam, Rakpong; Renaud, Rick; Lin, Lucy; Boermans, Herman; Leatherland, John

2005-01-01

This study examined the possibility that DDT and DDE, at sub-lethal exposure levels, exert direct effects on the biotransformation of gonadal steroids by rainbow trout (Oncorhynchus mykiss) ovarian follicles and embryos. Ovarian follicles were co-incubated with DDT or DDE at 0.01 or 1 mg l -1 to examine effects of the pesticides on basal or cAMP-activated steroidogenesis. Ovarian preparations were incubated with radiolabelled [ 3 H]pregnenolone ([ 3 H]P 5 ), and the tritiated metabolites of [ 3 H]P 5 metabolism were separated using high-performance liquid chromatography (HPLC). Testosterone (T) and 17β-estradiol (E 2 ) production were also measured using radioimmunoassay (RIA). Embryos were either exposed to the pesticides in ovo, or co-incubated in vitro with the pesticides. The effect of the pesticides on embryo steroid biotransformation was examined using a range of radioactively labelled substrates, including [ 3 H]P 5 , [ 3 H]progesterone ([ 3 H]P 4 ), [ 3 H]T and [ 3 H]E 2 . At the concentrations used, the pesticides had no significant effect on the relative amounts of unconjugated radiolabelled steroids formed by the biotransformation of [ 3 H]P 5 under conditions of basal or cAMP-stimulated ovarian steroidogenesis. However, DDT and DDE appeared to reduce the basal accumulation of androgen as a product of P 5 biotransformation by ovarian follicles. Basal or cAMP-stimulated total estrogen production was not affected. In addition, DDT at 1 mg l -1 and DDE at 0.01 mg l -1 significantly increased and decreased cAMP-stimulated T accumulation, respectively. Also DDT at 0.01 mg l -1 and DDE at 1 mg l -1 significantly increased and decreased basal E 2 accumulation, respectively. The steroid metabolites synthesized from the different substrates by embryos were essentially similar in both controls and pesticide-exposed groups, and the survival of embryos to hatch was not significantly affected by pesticide exposure, in ovo, with an approximately 90% hatchability in

The Pattern of Distribution of Peroxidase and H{sub 2}O{sub 2} in Hypocotyls of Pumpkin irradiated with Gamma Ray

Energy Technology Data Exchange (ETDEWEB)

Wi, Seung Gon; Chung, Byung Yeoup; Kim, Jae Sung; Kim, Jin Hong; Lee, Ju Woon; Baek, Myung Hwa; Chae, Hyo Seok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2005-07-01

Gamma radiation, one of ionizing radiations, has been reported to affect the morphological, anatomical, biochemical and physiological changes of plants at different dose levels. These effects at high level include inhibition in plant growth. Peroxidases (PODs) are mainly participations the process of lignification on the cell wall and protect the cell organelles in cytosol against the oxidative stresses by ROS (reactive oxygen species). Hydrogen peroxide (ROS) is normal metabolite in aerobic cells and the physiological steady concentrations (between 10{sup -7} and 10{sup -9}) are not particularly cytotoxic. When these concentrations are increased by ionizing radiation, they lead to cell lethality. Thus radiation-induced H{sub 2}O{sub 2} may appear as an important agent causing cell damage. In this study, a polyclonal antibody against peroxidase and cerium chloride as a trapping agent for H{sub 2}O{sub 2} were used to obtain for better information on the occurrence and distribution of POD and H{sub 2}O{sub 2} in the cytoplasm and walls of vascular bundle in hypocotyls of pumpkin.

[Underlying Mechanisms of Methamphetamine-Induced Self-Injurious Behavior and Lethal Effects in Mice].

Science.gov (United States)

Mori, Tomohisa; Sawaguchi, Toshiko

2018-01-01

Relatively high doses of psychostimulants induce neurotoxicity on the dopaminergic system and self-injurious behavior (SIB) in rodents. However the underlying neuronal mechanisms of SIB remains unclear. Dopamine receptor antagonists, N-methyl-D-aspartic acid (NMDA) receptor antagonists, Nitric Oxide Synthase (NOS) inhibitors and free radical scavengers significantly attenuate methamphetamine-induced SIB. These findings indicate that activation of dopamine as well as NMDA receptors followed by radical formation and oxidative stress, especially when mediated by NOS activation, is associated with methamphetamine-induced SIB. On the other hand, an increase in the incidence of polydrug abuse is a major problem worldwide. Coadministered methamphetamine and morphine induced lethality in more than 80% in mice, accompanied by an increase in the number of poly (ADP-ribose) polymerase (PARP)-immunoreactive cells in the heart, kidney and liver. The lethal effect and the increase in the incidence of rupture or PARP-immunoreactive cells induced by the coadministration of methamphetamine and morphine were significantly attenuated by pretreatment with a phospholipase A2 inhibitor or a radical scavenger, or by cooling of body from 30 to 90 min after drug administration. These results suggest that free radicals play an important role in the increased lethality induced by the coadministration of methamphetamine and morphine. Therefore, free radical scavengers and cooling are beneficial for preventing death that is induced by the coadministration of methamphetamine and morphine. These findings may help us better understand for masochistic behavior, which is a clinical phenomenon on SIB, as well as polydrug-abuse-induced acute toxicity.

Effects of radiation on aquatic organisms

International Nuclear Information System (INIS)

Kaur, Harbhajan; Lata, Poonam; Sharma, Ankush

2012-01-01

With the onset of nuclear age, nuclear fuel cycle products, nuclear medicine techniques, disposal of radio active wastes on land or in water, fall out of testing nuclear weapons has contributed large amount of radio nuclides to the water bodies. Radio nuclides can imbalance aquatic ecosystem resulting in danger to natural life. The biological effects of radiation on aquatic life are mortality, pathophysiological, reproductive, developmental and genetic changes. A broad review of the results obtained about the aquatic organisms related to different phyla indicates that the lower or less developed or more primitive organisms are more resistant than the higher or more advanced, developed and complex organisms to ionizing radiation. The algae, protozoa are more resistant than the insects, crustaceans, molluscs and fishes. The changes in sensitivity between different stages of development have also been noted. A review of the results of exposing salmonoid gametes, eggs, fingerlings and adults to X-rays supports the concepts that radio sensitivity decreases with age. This paper presents a selective review on effects of radiation and radio nuclides on the aquatic life. It include uses and sources of radiation, effective quantity of radiation, lethal and sub lethal effect, effects on survival, growth, reproduction, behaviour, metabolism, carcinogenicity and mutagenicity. (author)

An Immature Myeloid/Myeloid-Suppressor Cell Response Associated with Necrotizing Inflammation Mediates Lethal Pulmonary Tularemia.

Directory of Open Access Journals (Sweden)

Sivakumar Periasamy

2016-03-01

Full Text Available Inhalation of Francisella tularensis (Ft causes acute and fatal pneumonia. The lung cytokine milieu favors exponential Ft replication, but the mechanisms underlying acute pathogenesis and death remain unknown. Evaluation of the sequential and systemic host immune response in pulmonary tularemia reveals that in contrast to overwhelming bacterial burden or cytokine production, an overt innate cellular response to Ft drives tissue pathology and host mortality. Lethal infection with Ft elicits medullary and extra-medullary myelopoiesis supporting recruitment of large numbers of immature myeloid cells and MDSC to the lungs. These cells fail to mature and die, leading to subsequent necrotic lung damage, loss of pulmonary function, and host death that is partially dependent upon immature Ly6G+ cells. Acceleration of this process may account for the rapid lethality seen with Ft SchuS4. In contrast, during sub-lethal infection with Ft LVS the pulmonary cellular response is characterized by a predominance of mature neutrophils and monocytes required for protection, suggesting a required threshold for lethal bacterial infection. Further, eliciting a mature phagocyte response provides transient, but dramatic, innate protection against Ft SchuS4. This study reveals that the nature of the myeloid cell response may be the primary determinant of host mortality versus survival following Francisella infection.

An Immature Myeloid/Myeloid-Suppressor Cell Response Associated with Necrotizing Inflammation Mediates Lethal Pulmonary Tularemia

Science.gov (United States)

Periasamy, Sivakumar; Avram, Dorina; McCabe, Amanda; MacNamara, Katherine C.; Sellati, Timothy J.; Harton, Jonathan A.

2016-01-01

Inhalation of Francisella tularensis (Ft) causes acute and fatal pneumonia. The lung cytokine milieu favors exponential Ft replication, but the mechanisms underlying acute pathogenesis and death remain unknown. Evaluation of the sequential and systemic host immune response in pulmonary tularemia reveals that in contrast to overwhelming bacterial burden or cytokine production, an overt innate cellular response to Ft drives tissue pathology and host mortality. Lethal infection with Ft elicits medullary and extra-medullary myelopoiesis supporting recruitment of large numbers of immature myeloid cells and MDSC to the lungs. These cells fail to mature and die, leading to subsequent necrotic lung damage, loss of pulmonary function, and host death that is partially dependent upon immature Ly6G+ cells. Acceleration of this process may account for the rapid lethality seen with Ft SchuS4. In contrast, during sub-lethal infection with Ft LVS the pulmonary cellular response is characterized by a predominance of mature neutrophils and monocytes required for protection, suggesting a required threshold for lethal bacterial infection. Further, eliciting a mature phagocyte response provides transient, but dramatic, innate protection against Ft SchuS4. This study reveals that the nature of the myeloid cell response may be the primary determinant of host mortality versus survival following Francisella infection. PMID:27015566

Lethal doses of ionizing radiation versus endogenous level of superoxide dismutase

Energy Technology Data Exchange (ETDEWEB)

Lipecka, K; Domanski, T; Dniaszewska, K; Grabowska, B; Pietrowicz, D; Lindner, P; Cisowska, B; Gorski, H [Military Medical Academy, Lodz (Poland). Inst. of Occupational Medicine

1982-06-22

The stability of superoxide dismutase (SOD) as well as its activity distribution in a human population were investigated. The SOD activity level of the erythrocytes proved to be an index for the endogenous SOD activity in the whole body. In a rat population, having similar SOD frequency distribution as a human population, the mortality due to acute irradiation depended on the SOD level; after a single acute dose approximating the lethal dose (LD/sub 50/30/) the survival depended distinctly on the endogenous SOD activity level.

Evaluating the lethal and pre-lethal effects of a range of fungi against adult Anopheles stephensi mosquitoes

Directory of Open Access Journals (Sweden)

Blanford Simon

2012-11-01

Full Text Available Abstract Background Insecticide resistance is seriously undermining efforts to eliminate malaria. In response, research on alternatives to the use of chemical insecticides against adult mosquito vectors has been increasing. Fungal entomopathogens formulated as biopesticides have received much attention and have shown considerable potential. This research has necessarily focused on relatively few fungal isolates in order to ‘prove concept’. Further, most attention has been paid to examining fungal virulence (lethality and not the other properties of fungal infection that might also contribute to reducing transmission potential. Here, a range of fungal isolates were screened to examine variation in virulence and how this relates to additional pre-lethal reductions in feeding propensity. Methods The Asian malaria vector, Anopheles stephensi was exposed to 17 different isolates of entomopathogenic fungi belonging to species of Beauveria bassiana, Metarhizium anisopliae, Metarhizium acridum and Isaria farinosus. Each isolate was applied to a test substrate at a standard dose rate of 1×109 spores ml-1 and the mosquitoes exposed for six hours. Subsequently the insects were removed to mesh cages where survival was monitored over the next 14 days. During this incubation period the mosquitoes’ propensity to feed was assayed for each isolate by offering a feeding stimulant at the side of the cage and recording the number probing. Results and conclusions Fungal isolates showed a range of virulence to A. stephensi with some causing >80% mortality within 7 days, while others caused little increase in mortality relative to controls over the study period. Similarly, some isolates had a large impact on feeding propensity, causing >50% pre-lethal reductions in feeding rate, whereas other isolates had very little impact. There was clear correlation between fungal virulence and feeding reduction with virulence explaining nearly 70% of the variation in

Magnetovolume effects of quasi-one-dimensional itinerant electron magnets (La{sub 1-x}Y{sub x})Mn{sub 4}Al{sub 8}

Energy Technology Data Exchange (ETDEWEB)

Muro, Y. [Graduate School of Material Science, University of Hyogo, Kamigori, Ako-gun, Hyogo 678-1297 (Japan)]. E-mail: rk04j052@stkt.u-hyogo.ac.jp; Motoyama, G. [Graduate School of Material Science, University of Hyogo, Kamigori, Ako-gun, Hyogo 678-1297 (Japan); Nakamura, H. [Graduate School of Material Science, University of Hyogo, Kamigori, Ako-gun, Hyogo 678-1297 (Japan); Kohara, T. [Graduate School of Material Science, University of Hyogo, Kamigori, Ako-gun, Hyogo 678-1297 (Japan)

2006-05-01

Magnetovolume effects of 3d heavy-electron compounds with linear spin chains, (La{sub 1-x}Y{sub x})Mn{sub 4}Al{sub 8} with x=<0.15 and =1, have been investigated to get information on the ground state of LaMn{sub 4}Al{sub 8} and the nature of spin fluctuations in this system. The negative thermal expansion observed for LaMn{sub 4}Al{sub 8} is suppressed by the substitution of a small amount of Y for La. Together with the field-cooled effect in the susceptibility, the magnetovolume effect suggests the development of short-range magnetic correlation in LaMn{sub 4}Al{sub 8} at low temperatures.

Influence of CeO{sub 2} NPs on biological phosphorus removal and bacterial community shifts in a sequencing batch biofilm reactor with the differential effects of molecular oxygen

Energy Technology Data Exchange (ETDEWEB)

Xu, Yi; Wang, Chao [Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098 (China); College of Environment, Hohai University, Nanjing 210098 (China); Hou, Jun, E-mail: hhuhjyhj@126.com [Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098 (China); College of Environment, Hohai University, Nanjing 210098 (China); Wang, Peifang, E-mail: pfwang2005@hhu.edu.cn [Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098 (China); College of Environment, Hohai University, Nanjing 210098 (China); You, Guoxiang; Miao, Lingzhan; Lv, Bowen; Yang, Yangyang [Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098 (China); College of Environment, Hohai University, Nanjing 210098 (China)

2016-11-15

The effects of CeO{sub 2} nanoparticles (CeO{sub 2} NPs) on a sequencing batch biofilm reactor (SBBR) with established biological phosphorus (P) removal were investigated from the processes of anaerobic P release and aerobic P uptake. At low concentration (0.1 mg/L), no significant impact was observed on total phosphorus (TP) removal after operating for 8 h. However, at a concentration of 20 mg/L, TP removal efficiency decreased from 83.68% to 55.88% and 16.76% when the CeO{sub 2} NPs were added at the beginning of the anaerobic and aerobic periods, respectively. Further studies illustrated that the inhibition of the specific P release rate was caused by the reversible states of Ce{sup 3+} and Ce{sup 4+}, which inhibited the activity of exopolyphosphatase (PPX) and transformation of poly-β-hydoxyalkanoates (PHA) and glycogen, as well as the uptake of volatile fatty acids (VFAs). The decrease in the specific P uptake rate was mainly attributed to the significantly suppressed energy generation and decreased abundance of Burkholderia caused by excess reactive oxygen species. The removal of chemical oxygen demand (COD) was not influenced by CeO{sub 2} NPs under aerobic conditions, due to the increased abundance of Acetobacter and Acidocella after exposure. The inhibitory effects of CeO{sub 2} NPs with molecular oxygen were reduced after anaerobic exposure due to the enhanced particle size and the presence of Ce{sup 3+}. - Highlights: • CeO{sub 2} NPs (20 mg/L) had a notable toxicity effect on P removal in SBBR system. • The deteriorated SPRR was caused by the inhibited key enzyme activity (PPX). • The decreased SPUR was caused by the bacterial community shifts. • Ce ions converting and excess ROS generation are related toxicity mechanisms.

Biological Effects of Potato Plants Transformation with Glucose Oxidase Gene and their Resistance to Hyperthermia

Directory of Open Access Journals (Sweden)

O.I. Grabelnych

2017-02-01

Full Text Available It is known that regulation of plant tolerance to adverse environmental factors is connected with short term increase of the concentration of endogenous reactive oxygen species (ROS, which are signalling molecules for the induction of protective mechanisms. Introduction and expression of heterologous gox gene, which encodes glucose oxidase enzyme in plant genome, induce constantly higher content of hydrogen peroxide in plant tissues. It is not known how the introduction of native or modified gox gene affects the plant resistance to high-temperature stress, one of the most commonly used model for the study of stress response and thermal tolerance. In this study, we investigated biological effects of transformation and evaluated the resistance to temperature stress of potato plants with altered levels of glucose oxidase expression. Transformation of potato plants by gox gene led to the more early coming out from tuber dormancy of transformed plants and slower growth rate. Transformants containing the glucose oxidase gene were more sensitive to lethal thermal shock (50 °C, 90 min than the transformant with the empty vector (pBI or untransformed plants (CK. Pre-heating of plants at 37 °C significantly weakened the damaging effect of lethal thermal shock. This attenuation was more significant in the non-transformed plants.

Enhanced sensitivity to the lethal and mutagenic effects of photosensitizing action of chlorpromazine in ethylenediaminetetraacetate-treated Escherichia coli

International Nuclear Information System (INIS)

Yonei, S.; Todo, T.

1982-01-01

Ethylenediaminetetraacetate (EDTA) treatment of Escherichia coli H/r30 (Arg - ) enhanced cell sensitivity to the lethal and mutagenic effects of the photosensitizing action of chlorpromazine (CPZ). The most obvious effect of EDTA on the fluence-survival curve was an elimination of the shoulder. In the absence of EDTA, CPZ plus near-UV radiation did not induce the reversion from arginine-auxotroph to autotroph of E. coli H/r30. However, when EDTA (5 mM)-treated cells were subjected to CPZ plus near-UV radiation, the induced reversion frequency increased with time of irradiation. It is concluded that the enhanced penetration of CPZ into E. coli cells by EDTA facilitates the drug binding to DNA within the cells upon near-UV irradiation and that this is the cause for the enhanced photosensitized lethal and mutagenic effects of CPZ. (author)

High LET radiation and mechanism of DNA damage repair

International Nuclear Information System (INIS)

Furusawa, Yoshiya

2004-01-01

Clarifying the mechanism of repair from radiation damage gives most important information on radiation effects on cells. Approximately 10% of biological experiments groups in Heavy Ion Medical Accelerator in Chiba (HIMAC) cooperative research group has performed the subject. They gave a lot of new findings on the mechanism, and solved some open questions. The reason to show the peak of relative biological effectiveness RBE at around 100-200 keV/μm causes miss-repair of DNA damage. Sub-lethal damage generated by high linear energy transfer (LET) radiation can be repaired fully. Potentially lethal damages by high-LET radiation also repaired, but the efficiency decreased with the LET, and so on. (author)

Anomalous Pd substitution effects in the thermoelectric oxide NaCo sub 2 sub - sub x Pd sub x O sub 4

CERN Document Server

Kitawaki, R

2002-01-01

We prepared a set of polycrystalline samples of the thermoelectric oxide NaCo sub 2 sub - sub x Pd sub x O sub 4 (x = 0, 0.05, 0.1, and 0.2), and investigated the Pd substitution effects on transport phenomena. The effects are so drastic that just 5-10% Pd ions reduce the resistivity and the Seebeck coefficient to one third of the values for x = 0, and increase the magnitude of the Hall coefficient by three times. A semi-quantitative analysis has revealed that the x = 0.2 sample has much smaller effective mass and carrier concentration than the x = 0.05 sample. This is difficult to explain within a rigid-band picture, and is qualitatively consistent with a strong-correlation picture applied to the Ce-based heavy-fermion systems.

Chemical and biological effects of β-decay and inner shell ionization in biomolecules

International Nuclear Information System (INIS)

Stoecklin, G.

1979-01-01

Tritium and iodine-125, and the Auger effect either caused by the EC-decay of 125 I or by the inner shell vacancy created selectively by mono-energetic X-ray are reviewed in this paper. The specifically labelled precursors to bound 3 H large biomolecules were prepared by conventional syntheses, and then incorporated into the DNA of proliferating cells. The effects like DNA strand breaks or mutational changes are likely to be affected by the localization of the carbonium ions in biological molecules. In contrast to lethality, it was demonstrated that 3 H transmutation effect contributed to DNA strand breaks and played a key role in producing genetic effects. The decay of 3 H in uracil-5- 3 H in the DNA of E. coli was about 7 times as mutagenic as that in uracil-6- 3 H, and 500-fold greater in bacteriophage S13. Drastic chemical consequences are associated with the Auger effect occurring as a possible relaxation process whenever inner shell ionization is initiated. When the vacancy is filled by an electron from an outer shell, the bond energy difference between inner shell electron and outer shell electron is released either in the form of an X-ray fluorescence photon or it can be transmitted to another outer electron which is then ejected. The radioactive decay in specifically labelled biomolecules or the inner shell ionization in heavy constituent atoms caused by resonant X-ray are relevant to a) selective microsurgery in biological macromolecules for the correlation of biological and chemical functions, b) radiotoxicity estimation, and c) radiation therapy. (Yamashita, S.)

Assessing sub-Saharan Erythrina for efficacy: traditional uses, biological activities and phytochemistry.

OpenAIRE

Kone , Witabouna Mamidou; Solange , Kakou-Ngazoa E; Dosso , Mireille

2011-01-01

International audience; The genus Erythrina comprises more than 100 species, widely distributed in tropical and subtropical areas. In Africa, 31 wild species and 14 cultivated species have been described. In sub-Saharan Africa, Erythrina species are used to treat frequent parasitic and microbial diseases, inflammation, cancer, wounds. The rationale of these traditional uses in African traditional medicine was established by screening several species for biological activities. Promising activi...

MASM, a Matrine Derivative, Offers Radioprotection by Modulating Lethal Total-Body Irradiation-Induced Multiple Signaling Pathways in Wistar Rats

Directory of Open Access Journals (Sweden)

Jianzhong Li

2016-05-01

Full Text Available Matrine is an alkaloid extracted from Sophora flavescens Ait and has many biological activities, such as anti-inflammatory, antitumor, anti-fibrosis, and immunosuppressive properties. In our previous studies, the matrine derivative MASM was synthesized and exhibited potent inhibitory activity against liver fibrosis. In this study, we mainly investigated its protection against lethal total-body irradiation (TBI in rats. Administration of MASM reduced the radiation sickness characteristics and increased the 30-day survival of rats before or after lethal TBI. Ultrastructural observation illustrated that pretreatment of rats with MASM significantly attenuated the TBI-induced morphological changes in the different organs of irradiated rats. Gene expression profiles revealed that pretreatment with MASM had a dramatic effect on gene expression changes caused by TBI. Pretreatment with MASM prevented differential expression of 53% (765 genes of 1445 differentially expressed genes induced by TBI. Pathway enrichment analysis indicated that these genes were mainly involved in a total of 21 pathways, such as metabolic pathways, pathways in cancer, and mitogen-activated protein kinase (MAPK pathways. Our data indicated that pretreatment of rats with MASM modulated these pathways induced by TBI, suggesting that the pretreatment with MASM might provide the protective effects on lethal TBI mainly or partially through the modulation of these pathways, such as multiple MAPK pathways. Therefore, MASM has the potential to be used as an effective therapeutic or radioprotective agent to minimize irradiation damages and in combination with radiotherapy to improve the efficacy of cancer therapy.

Transesterification of palm oil on K{sub y}Mg{sub 1} {sub -} {sub x}Zn{sub 1} {sub +} {sub x}O{sub 3} catalyst: Effect of Mg-Zn interaction

Energy Technology Data Exchange (ETDEWEB)

Olutoye, M.A.; Hameed, B.H. [School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang (Malaysia)

2010-06-15

The Mg-Zn interaction effect of K{sub y}Mg{sub 1} {sub -} {sub x}Zn{sub 1} {sub +} {sub x}O{sub 3} heterogeneous type catalyst and its performance on transesterification of palm oil have been studied using the response surface methodology and the factorial design of experiments. The catalyst was synthesized using the co-precipitation method and the activity was assessed by transesterification of palm oil into fatty acid methyl esters. The ratio of the Mg/Zn metal interaction, temperature and time of calcination were found to have positive influence on the conversion of palm oil to fatty acid methyl ester (FAME) with the effect of metal to metal ratio and temperature of calcination being more significant. The catalytic activity was found to decrease at higher calcination temperature and the catalyst type K{sub 2}Mg{sub 0.34}Zn{sub 1.66}O{sub 3} with Mg/Zn ratio of 4.81 gave FAME content of 73% at a catalyst loading of 1.404 wt.% of oil with molar ratio of methanol to oil being 6:1 at temperature of 150 C in 6 h. A regression model was obtained to predict conversions to methyl esters as a function of metal interaction ratio, temperature of calcination and time. The observed activity of the synthesized catalyst was due to its synergetic structure and composition. (author)

Sub-chronic exposure to paraoxon neither induces nor exacerbates diabetes mellitus in Wistar rat.

Science.gov (United States)

Nurulain, Syed M; Petroianu, Georg; Shafiullah, Mohamed; Kalász, Huba; Oz, Murat; Saeed, Tariq; Adem, Abdu; Adeghate, Ernest

2013-10-01

There is an increasing belief that organophosphorus compounds (OPCs) impair glucose homeostasis and cause hyperglycemia and diabetes mellitus. The present study was undertaken to investigate the putative diabetogenic effect of sub-lethal and sub-chronic exposure to paraoxon (POX), an extremely hazardous OPC used in pesticides. The effect of paraoxon on streptozotocin-induced diabetic rats was also examined. Each rat was injected with 100 nmol of POX 5 days per week for 6 weeks. Blood glucose levels and red blood cell acetylcholinesterase activity were measured weekly. Biochemical analysis and morphological studies were performed at the end of the experiment. The results revealed that POX neither induces nor exacerbates diabetes mellitus in experimental rats. Liver and kidney/body weight ratios revealed statistically insignificant differences when compared with controls. Biochemical analysis of urine samples showed a small but not significant increase in protein level in all groups. Urine bilirubin was significantly higher in the diabetes + POX group when compared with the control group. The number of blood cells in urine was significantly higher in the POX-treated group compared with the control group. Hyperglycemia was noted in the diabetes and diabetes + POX groups, but neither in the saline control nor in POX-treated normal rats. Electron microscopy of POX-treated pancreas did not show any morphological changes in beta cells. These results suggest that POX does not cause diabetes mellitus at sub-lethal sub-chronic exposure. Copyright © 2012 John Wiley & Sons, Ltd.

Biological effect of ultrasoft x-ray, 1

International Nuclear Information System (INIS)

Narita, Noboru

1985-01-01

Biological effect on Escherichia coli by ultrasoft X-ray have been studied by comparing with that by uv light (2537 A) and by soft X-ray (40 kVp, 5 mA). Ultrasoft X-ray is aluminium characteristic X-ray (about 1.5 keV) produced by low energy electron collision on aluminium foil target and is obtained from Lea-type transmission target discharge tube. Escherichia coli used here are AB1157, AB1886 (uvrA6), JC1569 (recA), AB2470 (recB) and AB2480 (uvr rec) for inactivation experiment and WP2, WP2uvrA, WP2pKM101 and WP2uvrApKM101 for mutation induction experiment. These strains are all irradiated in buffer. Results obtained are summerized as follows : (i) inactivation by ultrasoft X-ray is located between ones by uv light and by soft X-ray, or ultrasoft X-ray gives a lethal damage that uvrA6 gene seems to contribute, and (ii) ultrasoft X-ray does not show the remarkable mutation induction like that induced by low dose irradiation of uv light or soft X-ray. (author)

Lethal and Sublethal Effects of Insecticides Used on Citrus, on the Ectoparasitoid Tamarixia radiata.

Science.gov (United States)

Beloti, Vitor Hugo; Alves, Gustavo Rodrigues; Araújo, Diogo Feliciano Dias; Picoli, Mateus Manara; Moral, Rafael de Andrade; Demétrio, Clarice Garcia Borges; Yamamoto, Pedro Takao

2015-01-01

Huanglongbing (HLB) is a disease associated with the bacteria "Candidatus Liberibacter spp." and has been devastating citrus orchards around the world. Its management involves control of the insect vector, the Asian citrus psyllid Diaphorina citri Kuwayama. However, the indiscriminate use of chemicals has caused pest outbreaks and eliminated the natural enemies of the vector, such as the parasitoid Tamarixia radiata (Waterston), the main agent for biological control of D. citri. This study assessed the lethal and sublethal effects of insecticides recommended for integrated production of citrus on the parasitoid T. radiata. When adult parasitoids were exposed to residues of 25 insecticides, 20% of them, i.e., gamma-cyhalothrin, etofenprox, azadirachtin, tebufenozide and pyriproxyfen, were considered as harmless (Class 1), 12% as slightly harmful (Class 2), 12% as moderately harmful (Class 3) and 56% as harmful (Class 4), according to the classification proposed by the IOBC/WPRS. Afterward, 14 insecticides (5 harmless and 9 harmful) were sprayed on the parasitoid pupae. Of the 14 insecticides tested, only the organophosphates dimethoate and chlorpyrifos affected the parasitoid emergence. The effects of insecticides on the parasitism capacity of adults exposed to residues of azadirachtin, etofenprox, gamma-cyhalothrin, pyriproxyfen and tebufenozide (harmless) were also evaluated. Tebufenozide and gamma-cyhalothrin affected the parasitism of the F0 generation, but did not affect the emergence of the F1 and F2 generations. Therefore, for an effective IPM program, selective insecticides or harmful pesticides to adult parasitoids could be used in the field, provided that the adults do not occur naturally and the chemical applications do not coincide with parasitoid releases.

Lethal and Sublethal Effects of Insecticides Used on Citrus, on the Ectoparasitoid Tamarixia radiata.

Directory of Open Access Journals (Sweden)

Vitor Hugo Beloti

Full Text Available Huanglongbing (HLB is a disease associated with the bacteria "Candidatus Liberibacter spp." and has been devastating citrus orchards around the world. Its management involves control of the insect vector, the Asian citrus psyllid Diaphorina citri Kuwayama. However, the indiscriminate use of chemicals has caused pest outbreaks and eliminated the natural enemies of the vector, such as the parasitoid Tamarixia radiata (Waterston, the main agent for biological control of D. citri. This study assessed the lethal and sublethal effects of insecticides recommended for integrated production of citrus on the parasitoid T. radiata. When adult parasitoids were exposed to residues of 25 insecticides, 20% of them, i.e., gamma-cyhalothrin, etofenprox, azadirachtin, tebufenozide and pyriproxyfen, were considered as harmless (Class 1, 12% as slightly harmful (Class 2, 12% as moderately harmful (Class 3 and 56% as harmful (Class 4, according to the classification proposed by the IOBC/WPRS. Afterward, 14 insecticides (5 harmless and 9 harmful were sprayed on the parasitoid pupae. Of the 14 insecticides tested, only the organophosphates dimethoate and chlorpyrifos affected the parasitoid emergence. The effects of insecticides on the parasitism capacity of adults exposed to residues of azadirachtin, etofenprox, gamma-cyhalothrin, pyriproxyfen and tebufenozide (harmless were also evaluated. Tebufenozide and gamma-cyhalothrin affected the parasitism of the F0 generation, but did not affect the emergence of the F1 and F2 generations. Therefore, for an effective IPM program, selective insecticides or harmful pesticides to adult parasitoids could be used in the field, provided that the adults do not occur naturally and the chemical applications do not coincide with parasitoid releases.

Bacillus anthracis lethal toxin disrupts TCR signaling in CD1d-restricted NKT cells leading to functional anergy.

Directory of Open Access Journals (Sweden)

Sunil K Joshi

2009-09-01

Full Text Available Exogenous CD1d-binding glycolipid (alpha-Galactosylceramide, alpha-GC stimulates TCR signaling and activation of type-1 natural killer-like T (NKT cells. Activated NKT cells play a central role in the regulation of adaptive and protective immune responses against pathogens and tumors. In the present study, we tested the effect of Bacillus anthracis lethal toxin (LT on NKT cells both in vivo and in vitro. LT is a binary toxin known to suppress host immune responses during anthrax disease and intoxicates cells by protective antigen (PA-mediated intracellular delivery of lethal factor (LF, a potent metalloprotease. We observed that NKT cells expressed anthrax toxin receptors (CMG-2 and TEM-8 and bound more PA than other immune cell types. A sub-lethal dose of LT administered in vivo in C57BL/6 mice decreased expression of the activation receptor NKG2D by NKT cells but not by NK cells. The in vivo administration of LT led to decreased TCR-induced cytokine secretion but did not affect TCR expression. Further analysis revealed LT-dependent inhibition of TCR-stimulated MAP kinase signaling in NKT cells attributable to LT cleavage of the MAP kinase kinase MEK-2. We propose that Bacillus anthracis-derived LT causes a novel form of functional anergy in NKT cells and therefore has potential for contributing to immune evasion by the pathogen.

Effects of hole doping on the electronic transport properties of PrBa sub 1 sub . sub 8 Sr sub 0 sub . sub 2 Cu sub 3 O sub y and PrSr sub 2 Cu sub 2 sub . sub 7 Mo sub 0 sub . sub 3 O sub y

CERN Document Server

Yang, C F; Zhang, H

2002-01-01

We investigate the effect of Ca doping on the electronic transport properties and superconductivity of Pr sub 1 sub - sub x Ca sub x Ba sub 1 sub . sub 8 Sr sub 0 sub . sub 2 Cu sub 3 O sub y and Pr sub 1 sub - sub x Ca sub x Sr sub 2 Cu sub 2 sub . sub 7 Mo sub 0 sub . sub 3 O sub y systems. It is found that when PrBa sub 2 Cu sub 3 O sub y (Pr123) is in a highly localized state, the Ca doping mainly decreases the 4f-2p hybridized states and thus releases the holes into the CuO sub 2 planes. Whereas when Pr123 is in a less localized state, the Ca doping not only introduces holes into the CuO sub 2 planes, but also induces dramatic charge transfer. Our results suggest that only when the hole concentration in both the CuO chain and the CuO sub 2 planes reaches a proper value, can the superconductivity be restored in the Pr123 system.

Effects of high dose rate gamma radiation on survival and reproduction of Biomphalaria glabrata

Energy Technology Data Exchange (ETDEWEB)

Cantinha, Rebeca S.; Nakano, Eliana [Instituto Butantan, Sao Paulo, SP (Brazil). Lab. de Parasitologia], e-mail: rebecanuclear@gmail.com, e-mail: eliananakano@butantan.gov.br; Borrely, Sueli I. [Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Sao Paulo, SP (Brazil). Centro de Tecnologia das Radiacoes], e-mail: sborrely@ipen.br; Amaral, Ademir; Melo, Ana M.M.A. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Estudos em Radioprotecao e Radioecologia (GERAR)], e-mail: amaral@ufpe.br; Silva, Luanna R.S. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Biofisica e Radiobiologia. Lab. de Radiobiologia], e-mail: amdemelo@hotmail.com, e-mail: luannaribeiro_lua@hotmail.com

2009-07-01

Ionizing radiations are known as mutagenic agents, causing lethality and infertility. This characteristic has motivated its application on animal biological control. In this context, the freshwater snail Biomphalaria glabrata can be considered an excellent experimental model to study effects of ionizing radiations on lethality and reproduction. This work was designed to evaluate effects of {sup 60}Co gamma radiation at high dose rate (10.04 kGy/h) on B. glabrata. For this purpose, adult snails were selected and exposed to doses ranging from 20 to 100 Gy, with 10 Gy intervals; one group was kept as control. There was not effect of dose rate in the lethality of gamma radiation; the value of 64,3 Gy of LD{sub 50} obtained in our study was similar to that obtained by other authors with low dose rates. Nevertheless, our data suggest that there was a dose rate effect in the reproduction. On all dose levels, radiation improved the production of embryos for all exposed individuals. However, viability indexes were below 6% and, even 65 days after irradiation, fertility was not recovered. These results are not in agreement with other studies using low dose rates. Lethality was obtained in all groups irradiated, and the highest doses presented percentiles of dead animals above 50%. The results demonstrated that doses of 20 and 30 Gy were ideal for population control of B. glabrata. Further studies are needed; nevertheless, this research evidenced great potential of high dose rate gamma radiation on B. glabrata reproductive control. (author)

Greenhouse effect of NO{sub x}

Energy Technology Data Exchange (ETDEWEB)

Lammel, G; Grassl, H [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany)

1995-07-01

Through various processes the nitrogen oxides (NO{sub x}) interact with trace gases in the troposphere and stratosphere which do absorb in the spectral range relevant to the greenhouse effect (infrared wavelengths). The net effect is an enhancement of the greenhouse effect. The catalytic role of NO{sub x} in the production of tropospheric ozone provides the most prominent contribution. The global waming potential is estimated as GWP (NO{sub x}) = 30-33 and 7-10 for the respective time horizons of 20 and 100 years, and is thereby comparable to that of methane. NO{sub x} emissions in rural areas of anthropogenically influenced regions, or those in the vicinity of the tropopause caused by air traffic, cause the greenhouse effectivity to be substantially more intense. We estimate an additional 5-23% for Germany`s contribution to the anthropogenic greenhouse effect as a result of the indirect greenhouse effects stemming from NO{sub x}. Furthermore, a small and still inaccurately defined amount of the deposited NO{sub x} which has primarily been converted into nitrates is again released from the soil into the atmosphere in the form of the long-lived greenhouse gas nitrous oxide (N{sub i}O). Thus, anthropogenically induced NO{sub x} emissions contribute to enhanced greenhouse effect and to stratospheric ozone depletion in the time scale of more than a century. (orig.)

Deletion of Indian hedgehog gene causes dominant semi-lethal Creeper trait in chicken

Science.gov (United States)

Jin, Sihua; Zhu, Feng; Wang, Yanyun; Yi, Guoqiang; Li, Junying; Lian, Ling; Zheng, Jiangxia; Xu, Guiyun; Jiao, Rengang; Gong, Yu; Hou, Zhuocheng; Yang, Ning

2016-01-01

The Creeper trait, a classical monogenic phenotype of chicken, is controlled by a dominant semi-lethal gene. This trait has been widely cited in the genetics and molecular biology textbooks for illustrating autosomal dominant semi-lethal inheritance over decades. However, the genetic basis of the Creeper trait remains unknown. Here we have utilized ultra-deep sequencing and extensive analysis for targeting causative mutation controlling the Creeper trait. Our results indicated that the deletion of Indian hedgehog (IHH) gene was only found in the whole-genome sequencing data of lethal embryos and Creeper chickens. Large scale segregation analysis demonstrated that the deletion of IHH was fully linked with early embryonic death and the Creeper trait. Expression analysis showed a much lower expression of IHH in Creeper than wild-type chickens. We therefore suggest the deletion of IHH to be the causative mutation for the Creeper trait in chicken. Our findings unravel the genetic basis of the longstanding Creeper phenotype mystery in chicken as the same gene also underlies bone dysplasia in human and mouse, and thus highlight the significance of IHH in animal development and human haploinsufficiency disorders. PMID:27439785

G/sub 2/ arrest in mouse zygotes after X-irradiation: reversion by caffeine and influence of chromosome abnormalities

Energy Technology Data Exchange (ETDEWEB)

Grinfeld, S.; Jacquet, P.

1988-08-01

The effect of caffeine was studied on mouse zygotes blocked in the G/sub 2/ phase of the first cell cycle after X-irradiation. Caffeine (2 mM) effectively reversed the G/sub 2/ arrest when zygotes were incubated in its presence at the time when first mitosis normally takes place. This effect of caffeine was inhibited by cycloheximide (5 ..mu..g ml/sup -1/). In embryos escaping the G/sub 2/ arrest the frequencies of chromosome aberrations varied as a function of the time of irradiation, showing a clear relationship with the varying rates of lethality occurring from the morula stage. Blocked zygotes suffered major chromosome damage: however, this did not appear to be the only cause of the G/sub 2/ arrest. Triploid zygotes were preferentially blocked, suggesting that nuclei contain the target for this X-ray effect.

Revertant mutation releases confined lethal mutation, opening Pandora's box: a novel genetic pathogenesis.

Directory of Open Access Journals (Sweden)

Yasushi Ogawa

2014-05-01

Full Text Available When two mutations, one dominant pathogenic and the other "confining" nonsense, coexist in the same allele, theoretically, reversion of the latter may elicit a disease, like the opening of Pandora's box. However, cases of this hypothetical pathogenic mechanism have never been reported. We describe a lethal form of keratitis-ichthyosis-deafness (KID syndrome caused by the reversion of the GJB2 nonsense mutation p.Tyr136X that would otherwise have confined the effect of another dominant lethal mutation, p.Gly45Glu, in the same allele. The patient's mother had the identical misssense mutation which was confined by the nonsense mutation. The biological relationship between the parents and the child was confirmed by genotyping of 15 short tandem repeat loci. Haplotype analysis using 40 SNPs spanning the >39 kbp region surrounding the GJB2 gene and an extended SNP microarray analysis spanning 83,483 SNPs throughout chromosome 13 in the family showed that an allelic recombination event involving the maternal allele carrying the mutations generated the pathogenic allele unique to the patient, although the possibility of coincidental accumulation of spontaneous point mutations cannot be completely excluded. Previous reports and our mutation screening support that p.Gly45Glu is in complete linkage disequilibrium with p.Tyr136X in the Japanese population. Estimated from statisitics in the literature, there may be approximately 11,000 p.Gly45Glu carriers in the Japanese population who have this second-site confining mutation, which acts as natural genetic protection from the lethal disease. The reversion-triggered onset of the disesase shown in this study is a previously unreported genetic pathogenesis based on Mendelian inheritance.

Comparative studies on the biology and filarial susceptibility of selected blood-feeding and autogenous Aedes togoi sub-colonies

Directory of Open Access Journals (Sweden)

Anuluck Junkum

2003-06-01

Full Text Available Blood-feeding and autogenous sub-colonies were selected from a laboratory, stock colony of Aedes togoi, which was originally collected from Koh Nom Sao, Chanthaburi province, Southeast Thailand. Comparative biology and filarial susceptibility between the two sub-colonies (blood-feeding: F11, F13; autogeny: F38, F40 were investigated to evaluate their viability and vectorial capacity. The results of comparison on biology revealed intraspecific differences, i.e., the average egg deposition/gravid female (F11/F38; F13/F40, embryonation rate (F13/F40, hatchability rate (F11/F38; F13/F40, egg width (F11/F38, wing length of females (F13/F40, and wing length and width of males (F11/F38 in the blood-feeding sub-colony were significantly greater than that in the autogenous sub-colony; and egg length (F11/F38 and width (F13/F40, and mean longevity of adult females (F11/F38 and males (F13/F40 in the blood-feeding sub-colony were significantly less than that in the autogenous sub-colony. The results of comparison on filarial susceptibility demonstrated that both sub-colonies yielded similar susceptibilities to Brugia malayi [blood-feeding/autogeny = 56.7% (F11/53.3%(F38, 60%(F13/83.3%(F40] and Dirofilaria immitis [blood-feeding/autogeny = 85.7%(F11/75%(F38, 45%(F13/29.4%(F40], suggesting autogenous Ae. togoi sub-colony was an efficient laboratory vector in study of filariasis.

Theoretical investigations on magnetocaloric effect in Er{sub 1−y}Tb{sub y}Al{sub 2} series

Energy Technology Data Exchange (ETDEWEB)

Ribeiro, P.O., E-mail: paula.ribeiro@gmail.com [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Alho, B.P.; Alvarenga, T.S.T.; Nóbrega, E.P.; Sousa, V.S.R. de [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Carvalho, A. Magnus G. [Laboratório Nacional de Luz Síncrotron, CNPEM, 13083-970 Campinas, SP (Brazil); Caldas, A. [Sociedade Unificada de Ensino Superior e Cultura, SUESC, 20211-351 Rio de Janeiro, RJ (Brazil); Oliveira, N.A. de; Ranke, P.J. von [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil)

2015-04-01

We report on the magnetic and magnetocaloric effect calculations in rare earth Er{sub 1−y}Tb{sub y}Al{sub 2} compounds (y=0.00, 0.25, 0.5, 0.75 and 1.00). Our model Hamiltonian has contributions of the crystalline electrical field anisotropy in both Er and Tb magnetic sublattices, disorder in exchange interactions among Er–Er, Tb–Tb and Er–Tb magnetic ions and the Zeeman effect. The magnetization, the isothermal entropy change (ΔS{sub T}) and the adiabatic temperature change (ΔT{sub ad}) dependence on temperature were simulated and, compared with the experimental data available. - Highlights: • Modeling Er{sub (1−y)}Tb{sub y}Al{sub 2} intermetallic compounds. • Magnetic entropy changes in Er{sub (1−y)}Tb{sub y}Al{sub 2}. • Adiabatic temperature changes in Er{sub 0.75}Tb{sub 0.25}Al{sub 2} and Er{sub 0.65}Tb{sub 0.35}Al{sub 2} compounds.

76 FR 44535 - Testing of Bisphenol A

Science.gov (United States)

2011-07-26

... variation in reported values for these sub-lethal effects, but many fall in the range of 1 [micro]g/L to 1... in brown trout at a very low concentration in water (1.75 [micro]g/L). Other effects such as the... ecological assessment of Bisphenol A: evidence from comparative biology. Reproductive Toxicology. Vol. 24:225...

Lethal Epistaxis.

Science.gov (United States)

Byard, Roger W

2016-09-01

Epistaxis or nosebleed refers to bleeding from the nostrils, nasal cavity, or nasopharynx. Occasional cases may present with torrential lethal hemorrhage. Three cases are reported to demonstrate particular features: Case 1: A 51-year-old woman with lethal epistaxis with no obvious bleeding source; Case 2: A 77-year-old man with treated nasopharyngeal carcinoma who died from epistaxis arising from a markedly neovascularized tumor bed; Case 3: A 2-year-old boy with hemophilia B who died from epistaxis with airway obstruction in addition to gastrointestinal bleeding. Epistaxis may be associated with trauma, tumors, vascular malformations, bleeding diatheses, infections, pregnancy, endometriosis, and a variety of different drugs. Careful dissection of the nasal cavity is required to locate the site of hemorrhage and to identify any predisposing conditions. This may be guided by postmortem computerized tomographic angiography (PCTA). Despite careful dissection, however, a source of bleeding may never be identified. © 2016 American Academy of Forensic Sciences.

Dominant-lethal mutations and heritable translocations in mice

Energy Technology Data Exchange (ETDEWEB)

Generoso, W.M.

1983-01-01

Chromosome aberrations are a major component of radiation or chemically induced genetic damage in mammalian germ cells. The types of aberration produced are dependent upon the mutagen used and the germ-cell stage treated. For example, in male meiotic and postmeiotic germ cells certain alkylating chemicals induce both dominant-lethal mutations and heritable translocations while others induce primarily dominant-lethal mutations. Production of these two endpoints appears to be determined by the stability of alkylation products with the chromosomes. If the reaction products are intact in the male chromosomes at the time of sperm entry, they may be repaired in fertilized eggs. If repair is not effected and the alkylation products persist to the time of pronuclear chromosome replication, they lead to chromatid-type aberrations and eventually to dominant-lethality. The production of heritable translocations, on the other hand, requires a transformation of unstable alkylation products into suitable intermediate lesions. The process by which these lesions are converted into chromosome exchange within the male genome takes place after sperm enters the egg but prior to the time of pronuclear chromosome replication (i.e., chromosome-type). Thus, dominant-lethal mutations result from both chromatid- and chromosome-type aberrations while heritable translocations result primarily from the latter type. DNA target sites associated with the production of these two endpoints are discussed.

Dominant-lethal mutations and heritable translocations in mice

International Nuclear Information System (INIS)

Generoso, W.M.

1983-01-01

Chromosome aberrations are a major component of radiation or chemically induced genetic damage in mammalian germ cells. The types of aberration produced are dependent upon the mutagen used and the germ-cell stage treated. For example, in male meiotic and postmeiotic germ cells certain alkylating chemicals induce both dominant-lethal mutations and heritable translocations while others induce primarily dominant-lethal mutations. Production of these two endpoints appears to be determined by the stability of alkylation products with the chromosomes. If the reaction products are intact in the male chromosomes at the time of sperm entry, they may be repaired in fertilized eggs. If repair is not effected and the alkylation products persist to the time of pronuclear chromosome replication, they lead to chromatid-type aberrations and eventually to dominant-lethality. The production of heritable translocations, on the other hand, requires a transformation of unstable alkylation products into suitable intermediate lesions. The process by which these lesions are converted into chromosome exchange within the male genome takes place after sperm enters the egg but prior to the time of pronuclear chromosome replication (i.e., chromosome-type). Thus, dominant-lethal mutations result from both chromatid- and chromosome-type aberrations while heritable translocations result primarily from the latter type. DNA target sites associated with the production of these two endpoints are discussed

Effect of Fe substitution on magnetocaloric effect in La{sub 0.7}Sr{sub 0.3}Mn{sub 1-x}Fe{sub x}O{sub 3} (0.05{<=}x{<=}0.20)

Energy Technology Data Exchange (ETDEWEB)

Barik, S K; Krishnamoorthi, C [Department of Physics and NUS Nanoscience and Nanotechnology Initiative, 2 Science Drive 3, National University of Singapore, Singapore 117542, Singapore. (Singapore); Mahendiran, R [Department of Physics and NUS Nanoscience and Nanotechnology Initiative, 2 Science Drive 3, National University of Singapore, Singapore 117542, Singapore. (Singapore)

2011-04-15

We have studied the effect of Fe substitution on magnetic and magnetocaloric properties in La{sub 0.7}Sr{sub 0.3}Mn{sub 1-x}Fe{sub x}O{sub 3} (x=0.05, 0.07, 0.10, 0.15, and 0.20) over a wide temperature range (T=10-400 K). It is shown that substitution by Fe gradually decreases the ferromagnetic Curie temperature (T{sub C}) and saturation magnetization up to x=0.15 but a dramatic change occurs for x=0.2. The x=0.2 sample can be considered as a phase separated compound in which both short-range ordered ferromagnetic and antiferromagnetic phases coexist. The magnetic entropy change (-{Delta}S{sub m}) was estimated from isothermal magnetization curves and it decreases with increase of Fe content from 4.4 J kg{sup -1} K{sup -1} at 343 K (x=0.05) to 1.3 J kg{sup -1} K{sup -1} at 105 K (x=0.2), under {Delta}H=5 T. The La{sub 0.7}Sr{sub 0.3}Mn{sub 0.93}Fe{sub 0.07}O{sub 3} sample shows negligible hysteresis loss, operating temperature range over 60 K around room temperature with refrigerant capacity of 225 J kg{sup -1}, and magnetic entropy of 4 J kg{sup -1} K{sup -1} which will be an interesting compound for application in room temperature refrigeration. - Research highlights: > We report magnetocaloric effect in La{sub 0.7}Sr{sub 0.3}Mn{sub 1-x}Fe{sub x}O{sub 3} (x=0-0.2). > Magnetic entropy change ({Delta}S{sub m}) decreases with increasing x. > A large {Delta}S{sub m} and refrigeration capacity are found around 300 K in x=0.07.

Comparative study of different sexis mutability: recessive sex-linked and dominant lethals in Drosophila melanogaster

International Nuclear Information System (INIS)

Vatti, K.V.; Dzhaparidze, L.A.; Mamon, L.A.

1980-01-01

The frequency of recessive sex-linked lethal mutations (RSLLM) and those realizing in embryogenesis of dominant lethals, which form in oo- and spermatogenesis of Drosophila and fly productivity under the effect of X-rays and N-nitroso-N methylourea (NMU), is studied. In the case of effect of both mutagens RSLLM form in spermatocytes with higher frequency as compared with oocytes. Dominant lethal mutations (DLM) during irradiation are also often registered in spermatocytes. NMU induces DLM in mitotic male cells with a very high frequency but is not effective during the effect on oocytes. When both mutagens affect males and X-rays affect females, the decrease of productivity is mainly conditioned by DLM. As NMU does not induce DLM in females realizing in embryogenesis but reduces productivity, a later lethal realization connected with their different nature is supposed. Differences in mole and female mutability found in the course of X-ray and NMU effect are discussed in connection with peculiarities of their mitotic cells and the nature of effect of mutagens applied [ru

The seeding effect of floating zone growth on Nd sub 1 sub . sub 8 sub 5 Ce sub 0 sub . sub 1 sub 5 CuO sub 4 and Bi sub 2 Sr sub 2 CaCu sub 2 O sub 8 sub - subdelta single crystals

CERN Document Server

Lin, C T; Liang, B

2002-01-01

Single crystals with the [100] orientation were selected and used as seeds to investigate the effect of travelling solvent floating zone growth on superconducting oxides of Nd sub 1 sub . sub 8 sub 5 Ce sub 0 sub . sub 1 sub 5 CuO sub 4 and Bi sub 2 Sr sub 2 CaCu sub 2 O sub 8 sub - subdelta. The number of nuclei was remarkably reduced and random nuclei could be eased when the seeding was applied during the growth of Nd sub 1 sub . sub 8 sub 5 Ce sub 0 sub . sub 1 sub 5 CuO sub 4 single crystals, compared to the crystals grown without seed. The crystal could preferentially grow on the seed although some additional nuclei occurred at the solid-liquid interface during the initial growth process. In consequence, the crystal ingot obtained is a large single grain having dimensions of 5 mm in diameter and 40 mm in length. The orientation of the seeded growth crystal was found to be 5deg off the [100] seed identified by an x-ray Laue pattern. For the growth of Bi sub 2 Sr sub 2 CaCu sub 2 O sub 8 sub - subdelta, it...

Nernst effect of Ni-doped NdBa{sub 2}Cu{sub 3}O{sub 7-{delta}} and transport properties in UPt{sub 2}Si{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Johannsen, Niko

2008-05-15

In this thesis, the Nernst effect in high-temperature superconductors is investigated. Large Nernst voltages were found to survive up to temperatures that reach far out of the superconducting phase. This was extensively studied thereafter in wide doping range of the high-T{sub c}'s. We were able to significantly expand these studies by tuning T{sup *} and T{sup {nu}} independently. This was done by inducing Ni ions into the CuO planes of NdBa{sub 2}{l_brace}Cu{sub 1-y}Ni{sub y}{r_brace}{sub 3}O{sub 7-{delta}} which allowed to study the Nernst effect in a wide parameter range. This is done on one hand in dependence of the oxygen content which varies the charge carrier concentration. On the other hand, the Ni concentration is varied from 0% to 12%, thereby enhancing T{sup *} and simultaneously suppressing T{sub c} with increasing concentrations. The temperatures to which the anomalous Nernst signal is detectable is the onset temperature T{sup {nu}}. The goal of this work was to find out whether T{sup {nu}} follows T{sub c} or T{sup *}. The onset temperatures of the anomalous Nernst signals are determined as the slightest detectable deviation from the quasiparticle background above T{sub c}. In the second part of this work, the Nernst effect and other transport properties of UPt{sub 2}Si{sub 2}, including electrical ones such as the resistivity and the Hall effect and thermal ones, as the thermal conductivity, the thermopower and the Righi-Leduc effect were investigated. (orig.)

A lethal ovitrap-based mass trapping scheme for dengue control in Australia: I. Public acceptability and performance of lethal ovitraps.

Science.gov (United States)

Ritchie, S A; Rapley, L P; Williams, C; Johnson, P H; Larkman, M; Silcock, R M; Long, S A; Russell, R C

2009-12-01

We report on the first field evaluation of the public acceptability and performance of two types of lethal ovitrap (LO) in three separate trials in Cairns, Australia. Health workers were able to set standard lethal ovitraps (SLOs) in 75 and 71% of premise yards in the wet and dry season, respectively, and biodegradable lethal ovitraps (BLOs) in 93% of yards. Public acceptance, measured as retention of traps by residents, was high for both trap types, with porous (grass, soil and mulch) versus solid (tiles, concrete, wood and stone) substrates. The SLOs and the BLOs were readily acceptable to ovipositing Aedes aegypti L. (Diptera: Culicidae); the mean number of eggs/trap was 6 and 15, for the dry season and wet season SLO trial, respectively, and 15 for the BLO wet season trial. Indeed, 84-94% of premise yards had egg positive SLOs or BLOs. A high percentage of both wet and dry season SLOs (29 and 70%, respectively) and BLOs (62%) that were dry after 4 weeks were egg positive, indicating the traps had functioned. Lethal strips from SLOs and BLOs that had been exposed for 4 weeks killed 83 and 74%, respectively, of gravid Ae. aegypti in laboratory assays. These results indicate that mass trapping schemes using SLOs and BLOs are not rejected by the public and effectively target gravid Ae. aegypti. The impact of the interventions on mosquito populations is described in a companion paper.

QTL mapping of inbreeding-related cold sensitivity and conditional lethality in Drosophila melanogaster

DEFF Research Database (Denmark)

Vermeulen, Corneel J.; Bijlsma, R.; Loeschcke, Volker

2008-01-01

of inbreeding-related and conditionally expressed lethality in Drosophila melanogaster. The lethal effect was triggered by exposure to a cold shock. We used a North Carolina crossing Design 3 to establish the mapping population, as well as to estimate the average dominance ratio and heritability. We found two......Inbreeding depression is a central theme within genetics, and is of specific interest for researchers within evolutionary and conservation genetics and animal and plant breeding. Inbreeding effects are thought to be caused by the joint expression of conditional and unconditional deleterious alleles....... Whenever the expression of deleterious alleles is conditional, this can result in extreme environmental sensitivity in certain inbred lineages. Analysis of conditional lethal effects can reveal some of the loci that are sensitive to inbreeding. We performed a QTL (quantitative trait locus) mapping study...

Switchable photovoltaic effect in Au/Bi{sub 0.9}La{sub 0.1}FeO{sub 3}/La{sub 0.7}Sr{sub 0.3}MnO{sub 3} heterostructures

Energy Technology Data Exchange (ETDEWEB)

Gao, Rongli, E-mail: gaorongli2008@163.com [School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing, 401331 (China); Chongqing Key Laboratory of Nano/Micro Composite Materials and Devices, Chongqing, 401331 (China); Fu, Chunlin; Cai, Wei; Chen, Gang; Deng, Xiaoling; Cao, Xianlong [School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing, 401331 (China); Chongqing Key Laboratory of Nano/Micro Composite Materials and Devices, Chongqing, 401331 (China)

2016-09-15

Bi{sub 0.9}La{sub 0.1}FeO{sub 3} (BLFO) films were fabricated on La{sub 0.7}Sr{sub 0.3}MnO{sub 3} (LSMO)/SrTiO{sub 3}(STO)(001) substrates by pulsed laser deposition. The ferroelectric photovoltaic characteristics of Au/BLFO/LSMO heterostructures were studied under green light illumination. The open circuit voltage and short circuit current were observed to be positive and negative values under weak light illumination in the as-grown self-poled downward BLFO thin films, while they changed the signs when the light intensity is strong. On the contrary, this photovoltaic properties can be switched when the BLFO films were in poled up state. The photovoltaic effect was also strongly dependent on the polarization direction, incident light intensity and the distribution of oxygen vacancies. As a result, the sign of open circuit voltage and short circuit current could be independent of the direction of polarization. We believe that the switchable diode and photovoltaic effects can be explained well using the concepts of Schottky barrier modulation by polarization flipping and of oxygen vacancies and the distribution of oxygen vacancies at Au/BLFO or BLFO/LSMO interface. Our work provides deep insights into the nature of diode and photovoltaic effects in ferroelectric films, implying an effective approach to improve photovoltaic effect by tuning oxygen vacancies in ferroelectric materials. - Highlights: • Pure phase Bi{sub 0.9}La{sub 0.1}FeO{sub 3} thin films were grown using pulsed laser deposition. • The as grown films were self poled and the polarization direction is downward. • The switchable photovoltaic effect depend on ferroelectric polarization directions. • Photovoltaic effect can be switched by changing the intensity of incident radiation. • Depolarization field and oxygen vacancies together induce the photovoltaic effect.

Lethal congenital contracture syndrome (LCCS) and other lethal arthrogryposes in Finland--an epidemiological study.

Science.gov (United States)

Pakkasjärvi, Niklas; Ritvanen, Annukka; Herva, Riitta; Peltonen, Leena; Kestilä, Marjo; Ignatius, Jaakko

2006-09-01

Arthrogryposis multiplex congenita is a heterogeneous group of disorders characterized by multiple contractures with an estimated frequency of 1 in 3,000 births. With improving diagnostic methods, increasing numbers of fetuses with arthrogryposis are found. The pathogenetic mechanisms are relatively well known but the epidemiology and genetics of the prenatally lethal forms of arthrogryposis are less well known. In this study we collected all cases of a multiple contractures diagnosed in Finland during 1987-2002 including live born infants, stillbirths, and terminated pregnancies. Ninety-two cases of 214 suffered intrauterine demise (68 selective pregnancy terminations and 24 stillbirths) and 58 died in infancy. In 141 out of these cases the diagnosis could be included within lethal arthrogryposes, with a prevalence of 1 in 6,985 (1.43/10,000) births. Of these, 59 had spinal cord pathology at autopsy and thus were of neurogenic origin. Thirty-nine cases had lethal congenital contracture syndrome (LCCS) clinically characterized by total immobility of the fetus at all ultrasound examinations (12 weeks or later), multiple joint contractures in both upper and lower limbs, hydrops, and fetal death before the 32nd week of pregnancy. LCCS is noted as a unique Finnish disorder with a prevalence of 1 in 25,250 (0.40/10,000) births and is a major cause of lethal arthrogryposis in Finland.

Theoretical investigations on the magnetocaloric and barocaloric effects in Tb{sub y}Gd{sub (1−y)}Al{sub 2} series

Energy Technology Data Exchange (ETDEWEB)

Ribeiro, P.O.; Alho, B.P.; Alvarenga, T.S.T.; Nóbrega, E.P. [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Carvalho, A.Magnus G. [Instituto de Ciência e Tecnologia, Universidade Federal de São Paulo – UNIFESP, 12231-280 São José dos Campos, SP (Brazil); Instituto Nacional de Metrologia, Qualidade e Tecnologia – INMETRO, 25250-020 Duque de Caxias, RJ (Brazil); Sousa, V.S.R. de; Caldas, A.; Oliveira, N.A. de [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil); Ranke, P.J. von, E-mail: von.ranke@uol.com.br [Instituto de Física, Universidade do Estado do Rio de Janeiro – UERJ, Rua São Francisco Xavier, 524, 20550-013 RJ (Brazil)

2013-06-25

Highlights: ► Anisotropic magnetocaloric effect in in Tb{sub 0.4}Gd{sub 0.6}Al{sub 2}. ► Prediction of barocaloric effect in Tb{sub 0.4}Gd{sub 0.6}Al{sub 2}. ►An optimal hybrid magnetocaloric material using Tb{sub y}Gd{sub (1-y)}Al{sub 2} compounds. -- Abstract: We report the calculations on the magnetocaloric and barocaloric effects in ferromagnetic series Tb{sub y}Gd{sub (1−y)}Al{sub 2}. Our model includes the crystalline electrical field interaction, exchange interactions among Tb–Tb, Gd–Gd and Tb–Gd magnetic ions and the Zeeman effect for an anisotropic system. The lattice and electronic entropies were included in adiabatic processes. The magnetocaloric effect calculated for magnetic field changes along the easy magnetic direction 〈1 1 1〉 is in good agreement with the experimental data. Calculation along the hard magnetization direction 〈0 0 1〉 predicts anomalous magnetocaloric effect, which was ascribed to the spin reorientation processes. From the available experimental data of Curie temperature dependence on pressure, the exchange model parameters were scaled and the barocaloric effect was calculated.

Toxicity of nanoparticulate and bulk ZnO, Al{sub 2}O{sub 3} and TiO{sub 2} to the nematode Caenorhabditis elegans

Energy Technology Data Exchange (ETDEWEB)

Wang Huanhua; Wick, Robert L. [Department of Plant, Soil and Insect Sciences, University of Massachusetts, Stockbridge Hall, Amherst, MA 01003 (United States); Xing Baoshan [Department of Plant, Soil and Insect Sciences, University of Massachusetts, Stockbridge Hall, Amherst, MA 01003 (United States)], E-mail: bx@pssci.umass.edu

2009-04-15

Limited information is available on the environmental behavior and associated potential risk of manufactured oxide nanoparticles (NPs). In this research, toxicity of nanoparticulate and bulk ZnO, Al{sub 2}O{sub 3} and TiO{sub 2} were examined to the nematode Caenorhabditis elegans with Escherichia coli as a food source. Parallel experiments with dissolved metal ions from NPs were also conducted. The 24-h median lethal concentration (LC{sub 50}) and sublethal endpoints were assessed. Both NPs and their bulk counterparts were toxic, inhibiting growth and especially the reproductive capability of the nematode. The 24-h LC{sub 50} for ZnO NPs (2.3 mg L{sup -1}) and bulk ZnO was not significantly different, but significantly different between Al{sub 2}O{sub 3} NPs (82 mg L{sup -1}) and bulk Al{sub 2}O{sub 3} (153 mg L{sup -1}), and between TiO{sub 2} NPs (80 mg L{sup -1}) and bulk TiO{sub 2} (136 mg L{sup -1}). Oxide solubility influenced the toxicity of ZnO and Al{sub 2}O{sub 3} NPs, but nanoparticle-dependent toxicity was indeed observed for the investigated NPs. - ZnO, Al{sub 2}O{sub 3} and TiO{sub 2} nanoparticles are more toxic than their bulk counterparts to the nematode, Caenorhabditis elegans.

Micronutrient special issue: Coenzyme Q{sub 10} requirements for DNA damage prevention

Energy Technology Data Exchange (ETDEWEB)

Schmelzer, Constance, E-mail: schmelzer@fbn-dummerstorf.de [Leibniz Institute for Farm Animal Biology (FBN), Nutritional Physiology, Wilhelm-Stahl-Allee 2, 18196 Dummerstorf (Germany); Doering, Frank [University of Kiel, Institute of Human Nutrition and Food Science, Molecular Prevention, Heinrich-Hecht-Platz 10, 24118 Kiel (Germany)

2012-05-01

Coenzyme Q{sub 10} (CoQ{sub 10}) is an essential component for electron transport in the mitochondrial respiratory chain and serves as cofactor in several biological processes. The reduced form of CoQ{sub 10} (ubiquinol, Q{sub 10}H{sub 2}) is an effective antioxidant in biological membranes. During the last years, particular interest has been grown on molecular effects of CoQ{sub 10} supplementation on mechanisms related to DNA damage prevention. This review describes recent advances in our understanding about the impact of CoQ{sub 10} on genomic stability in cells, animals and humans. With regard to several in vitro and in vivo studies, CoQ{sub 10} provides protective effects on several markers of oxidative DNA damage and genomic stability. In comparison to the number of studies reporting preventive effects of CoQ{sub 10} on oxidative stress biomarkers, CoQ{sub 10} intervention studies in humans with a direct focus on markers of DNA damage are limited. Thus, more well-designed studies in healthy and disease populations with long-term follow up results are needed to substantiate the reported beneficial effects of CoQ{sub 10} on prevention of DNA damage.

Combined application of sub-toxic level of silver nanoparticles with low powers of 2450 MHz microwave radiation lead to kill Escherichia coli in a short time

Directory of Open Access Journals (Sweden)

Bardia Varastehmoradi

2013-09-01

Full Text Available   Objective(s: Electromagnetic radiations which have lethal effects on the living cells are currently also considered as a disinfective physical agent.   Materials and Methods: In this investigation, silver nanoparticles were applied to enhance the lethal action of low powers (100 and 180 W of 2450 MHZ electromagnetic radiation especially against Escherichia coli ATCC 8739. Silver nanoparticles were biologically prepared and used for next experiments. Sterile normal saline solution was prepared and supplemented by silver nanoparticles to reach the sub-inhibitory concentration (6.25 μg/mL. Such diluted silver colloid as well as free-silver nanoparticles solution was inoculated along with test microorganisms, particularly E. coli. These suspensions were separately treated by 2450 MHz electromagnetic radiation for different time intervals in a microwave oven operated at low powers (100 W and 180 W. The viable counts of bacteria before and after each radiation time were determined by colony-forming unit (CFU method. Results: Results showed that the addition of silver nanoparticles significantly decreased the required radiation time to kill vegetative forms of microorganisms. However, these nanoparticles had no combined effect with low power electromagnetic radiation when used against Bacillus subtilis spores. Conclusion: The cumulative effect of silver nanoparticles and low powers electromagnetic radiation may be useful in medical centers to reduce contamination in polluted derange and liquid wastes materials and some devices.

Effect of sulfhydryls on potentiation of radiation-induced cell lethality by substituted anthraquinones

International Nuclear Information System (INIS)

Kimler, B.F.

1984-01-01

The effects of various substituted anthraquinones (SAQ's) and Adriamycin (ADR) were investigated in cultured Chinese hamster V79 cells. These drugs cause a potentiation of radiation-induced cell lethality, albeit by different mechanisms. One possibility is that these components operate through the production of free radicals which then produce DNA strand breaks and crosslinks. If so, then one should be able to change the degree of cell kill by modifying sulfhydryl (SH) levels such that free radical processes are altered. Diamide, buthionine-S, R-sulfoximine, and N-ethylmaleimide (NEM) were used to reduce intracellular SH levels. Cysteamine and dithiotheitol were used to increase SH levels. In general, altered SH levels did not affect SAQ-induced cytotoxicity at low drug concentrations. When drug-tested cells were also irradiated, survival levels were generally those predicted from assuming purely additive interactions. On the other hand, survival after treatment with high concentrations of ADR and one other SAQ were decreased by concomitant treatment with NEM. Since altered SH levels do not produce changes in the potentiation of radiation-induced cell lethality by SAQs, it is concluded that free radicals are not involved in this potentiation. A free radical-mediated process may be involved in the cytotoxicity induced by ADR and other SAQs; however, it is not a simple process

Effect of vacancies on the structure and properties of Ga{sub 2}(Se{sub 0.33}Te{sub 0.67}){sub 3}

Energy Technology Data Exchange (ETDEWEB)

Abdul-Jabbar, N. M. [Department of Nuclear Engineering, University of California, Berkeley, California 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Materials Department, University of California, Santa Barbara, California 93106 (United States); Forrest, T. R. [European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex (France); Department of Physics, University of California, Berkeley, California 94720 (United States); Gronsky, R. [Department of Materials Science and Engineering, University of California, Berkeley, California 94720 (United States); Bourret-Courchesne, E. D. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Wirth, B. D. [Department of Nuclear Engineering, University of California, Berkeley, California 94720 (United States); Department of Nuclear Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States)

2015-08-28

Ga{sub 2}(Se{sub 0.33}Te{sub 0.67}){sub 3} belongs to a family of materials with large intrinsic vacancy concentrations that are being actively studied due to their potential for diverse applications that include thermoelectrics and phase-change memory. In this article, the Ga{sub 2}(Se{sub 0.33}Te{sub 0.67}){sub 3} structure is investigated via synchrotron x-ray diffraction, electron microscopy, and x-ray absorption experiments. Diffraction and microscopy measurements showed that the extent of vacancy ordering in Ga{sub 2}(Se{sub 0.33}Te{sub 0.67}){sub 3} is highly dependent on thermal annealing. It is posited that stoichiometric vacancies play a role in local atomic distortions in Ga{sub 2}(Se{sub 0.33}Te{sub 0.67}){sub 3} (based on the fine structure signals in the collected x-ray absorption spectra). The effect of vacancy ordering on Ga{sub 2}(Se{sub 0.33}Te{sub 0.67}){sub 3} material properties is also examined through band gap and Hall effect measurements, which reveal that the Ga{sub 2}(Se{sub 0.33}Te{sub 0.67}){sub 3} band gap redshifts by ≈0.05 eV as the vacancies order and accompanied by gains in charge carrier mobility. The results serve as an encouraging example of altering material properties via intrinsic structural rearrangement as opposed to extrinsic means, such as doping.

WE-H-BRA-07: Mechanistic Modelling of the Relative Biological Effectiveness of Heavy Charged Particles

Energy Technology Data Exchange (ETDEWEB)

McMahon, S [Massachusetts General Hospital, Boston, MA (United States); Queen’s University, Belfast, Belfast (United Kingdom); McNamara, A; Schuemann, J; Paganetti, H [Massachusetts General Hospital, Boston, MA (United States); Prise, K [Queen’s University, Belfast, Belfast (United Kingdom)

2016-06-15

Purpose Uncertainty in the Relative Biological Effectiveness (RBE) of heavy charged particles compared to photons remains one of the major uncertainties in particle therapy. As RBEs depend strongly on clinical variables such as tissue type, dose, and radiation quality, more accurate individualised models are needed to fully optimise treatments. MethodsWe have developed a model of DNA damage and repair following X-ray irradiation in a number of settings, incorporating mechanistic descriptions of DNA repair pathways, geometric effects on DNA repair, cell cycle effects and cell death. Our model has previously been shown to accurately predict a range of biological endpoints including chromosome aberrations, mutations, and cell death. This model was combined with nanodosimetric models of individual ion tracks to calculate the additional probability of lethal damage forming within a single track. These lethal damage probabilities can be used to predict survival and RBE for cells irradiated with ions of different Linear Energy Transfer (LET). ResultsBy combining the X-ray response model with nanodosimetry information, predictions of RBE can be made without cell-line specific fitting. The model’s RBE predictions were found to agree well with empirical proton RBE models (Mean absolute difference between models of 1.9% and 1.8% for cells with α/β ratios of 9 and 1.4, respectively, for LETs between 0 and 15 keV/µm). The model also accurately recovers the impact of high-LET carbon ion exposures, showing both the reduced efficacy of ions at extremely high LET, as well as the impact of defects in non-homologous end joining on RBE values in Chinese Hamster Ovary cells.ConclusionOur model is predicts RBE without the inclusion of empirical LET fitting parameters for a range of experimental conditions. This approach has the potential to deliver improved personalisation of particle therapy, with future developments allowing for the calculation of individualised RBEs. SJM is

Lethal and sublethal effects of imidacloprid on Osmia lignaria and clothianidin on Megachile rotundata (Hymenoptera: Megachilidae).

Science.gov (United States)

Abbott, V A; Nadeau, J L; Higo, H A; Winston, M L

2008-06-01

We examined lethal and sublethal effects of imidacloprid on Osmia lignaria (Cresson) and clothianidin on Megachile rotundata (F.) (Hymenoptera: Megachilidae). We also made progress toward developing reliable methodology for testing pesticides on wild bees for use in pesticide registration by using field and laboratory experiments. Bee larvae were exposed to control, low (3 or 6 ppb), intermediate (30 ppb), or high (300 ppb) doses of either imidacloprid or clothianidin in pollen. Field experiments on both bee species involved injecting the pollen provisions with the corresponding pesticide. Only O. lignaria was used for the laboratory experiments, which entailed both injecting the bee's own pollen provisions and replacing the pollen provision with a preblended pollen mixture containing imidacloprid. Larval development, emergence, weight, and mortality were monitored and analyzed. There were no lethal effects found for either imidacloprid or clothianidin on O. lignaria and M. rotundata. Minor sublethal effects were detected on larval development for O. lignaria, with greater developmental time at the intermediate (30 ppb) and high doses (300 ppb) of imidacloprid. No similar sublethal effects were found with clothianidin on M. rotundata. We were successful in creating methodology for pesticide testing on O. lignaria and M. rotundata; however, these methods can be improved upon to create a more robust test. We also identified several parameters and developmental stages for observing sublethal effects. The detection of sublethal effects demonstrates the importance of testing new pesticides on wild pollinators before registration.

Calcium-Sensing Receptor Tumor Expression and Lethal Prostate Cancer Progression.

Science.gov (United States)

Ahearn, Thomas U; Tchrakian, Nairi; Wilson, Kathryn M; Lis, Rosina; Nuttall, Elizabeth; Sesso, Howard D; Loda, Massimo; Giovannucci, Edward; Mucci, Lorelei A; Finn, Stephen; Shui, Irene M

2016-06-01

Prostate cancer metastases preferentially target bone, and the calcium-sensing receptor (CaSR) may play a role in promoting this metastatic progression. We evaluated the association of prostate tumor CaSR expression with lethal prostate cancer. A validated CaSR immunohistochemistry assay was performed on tumor tissue microarrays. Vitamin D receptor (VDR) expression and phosphatase and tensin homolog tumor status were previously assessed in a subset of cases by immunohistochemistry. Cox proportional hazards models adjusting for age and body mass index at diagnosis, Gleason grade, and pathological tumor node metastasis stage were used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association of CaSR expression with lethal prostate cancer. The investigation was conducted in the Health Professionals Follow-up Study and Physicians' Health Study. We studied 1241 incident prostate cancer cases diagnosed between 1983 and 2009. Participants were followed up or cancer-specific mortality or development of metastatic disease. On average, men were followed up 13.6 years, during which there were 83 lethal events. High CaSR expression was associated with lethal prostate cancer independent of clinical and pathological variables (HR 2.0; 95% CI 1.2-3.3). Additionally, there was evidence of effect modification by VDR expression; CaSR was associated with lethal progression among men with low tumor VDR expression (HR 3.2; 95% CI 1.4-7.3) but not in cases with high tumor VDR expression (HR 0.8; 95% CI 0.2-3.0). Tumor CaSR expression is associated with an increased risk of lethal prostate cancer, particularly in tumors with low VDR expression. These results support further investigating the mechanism linking CaSR with metastases.

Biological Effects of Ionizing Radiation

Science.gov (United States)

Ingram, M.; Mason, W. B.; Whipple, G. H.; Howland, J. W.

1952-04-07

This report presents a review of present knowledge and concepts of the biological effects of ionizing radiations. Among the topics discussed are the physical and chemical effects of ionizing radiation on biological systems, morphological and physiological changes observed in biological systems subjected to ionizing radiations, physiological changes in the intact animal, latent changes following exposure of biological systems to ionizing radiations, factors influencing the biological response to ionizing radiation, relative effects of various ionizing radiations, and biological dosimetry.

Emission control of odour and N{sub 2}O from a mechanical biological pretreatment; Geruchsstoffe und N{sub 2}O im Abgas einer mechanisch-biologischen Abfallbehandlungsanlage

Energy Technology Data Exchange (ETDEWEB)

Cuhls, C.; Clemens, J. [Gesellschaft fuer Wissenstransfer, Bonn (Germany); Stockinger, J.; Doedens, H. [Hannover Univ. (Germany). Inst. fuer Siedlungswasserwirtschaft und Abfalltechnik

2002-04-01

Within the mechanical biological pretreatment (MBP) the aerobic treatment of waste is the major source of gaseous emissions. So far, the exhaust air has been treated by biofilters. But biofilters may act as a source of nitric and nitrous oxide (NO and N{sub 2}O) formed by excess ammonia (NH{sub 3}) and cannot oxidize methane (CH{sub 4}). As a consequence, biofilters may not be suitable to match the demands of the 30. Immission Ordinance (BImSchV). Thermal oxidation is able to keep total carbon below the new thresholds. NH{sub 3} is transformed to NO and NO{sub 2} uring the thermal oxidation. Depending on the oxidation temperature N{sub 2}O may be formed. When exhaust air was treated by scrubbing with mineral acid, N{sub 2}O, NO{sub x} and odour emissions were reduced. Four different teams measured odour concentrations in the treated air. There were differences of factor 10 between the results even when the teams analysed the same sample with the same olfactometer. These results suggest to improve the methodology of odour measurements at least for this application. (orig.)

Hidden order and disorder effects in URu{sub 2}Si{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Bernal, O.O. [California State University, Los Angeles, CA (United States)]. E-mail: obernal@calstatela.edu; Moroz, M.E. [California State University, Los Angeles, CA (United States); Ishida, K. [Graduate School of Science, Kyoto University, Kyoto (Japan); Murakawa, H. [Graduate School of Science, Kyoto University, Kyoto (Japan); Reyes, A.P. [National High Magnetic Field Lab, Tallahassee, FL (United States); Kuhns, P.L. [National High Magnetic Field Lab, Tallahassee, FL (United States); MacLaughlin, D.E. [University of California, Riverside, CA (United States); Mydosh, J.A. [Max Planck Institute for Chemical Physics of Solids, Dresden (Germany); Gortenmulder, T.J. [Kamerlingh Onnes Lab, Leiden University (Netherlands)

2006-05-01

NMR experiments at ambient pressure in URu{sub 2}Si{sub 2} demonstrate a linewidth enhancement effect below the hidden order transition temperature T{sub 0}. We present single-crystal {sup 29}Si NMR parameters for various temperatures and for an applied magnetic field perpendicular to the crystal c-axis. By comparing oriented-powder and single-crystal data, we observe that the size of the linewidth enhancement below T{sub 0} correlates with the size of the high-T broadening. We measure a {sup 29}Si up-field line shift below T{sub 0} which indicates the presence of an internal-field average for the entire crystal. This shift also correlates with the high-temperature width. The {sup 101}Ru NQR frequency as a function of temperature was also measured. No strong effect on the NQR frequency is observed at T{sub 0}. Both NMR and NQR measurements suggest a connection between linewidth/disorder effects and the transition to hidden order.

In brown adipocytes, adrenergically induced β{sub 1}-/β{sub 3}-(G{sub s})-, α{sub 2}-(G{sub i})- and α{sub 1}-(G{sub q})-signalling to Erk1/2 activation is not mediated via EGF receptor transactivation

Energy Technology Data Exchange (ETDEWEB)

Wang, Yanling; Fälting, Johanna M.; Mattsson, Charlotte L.; Holmström, Therése E.; Nedergaard, Jan, E-mail: jan@metabol.su.se

2013-10-15

Brown adipose tissue is unusual in that the neurotransmitter norepinephrine influences cell destiny in ways generally associated with effects of classical growth factors: regulation of cell proliferation, of apoptosis, and progression of differentiation. The norepinephrine effects are mediated through G-protein-coupled receptors; further mediation of such stimulation to e.g. Erk1/2 activation is in cell biology in general accepted to occur through transactivation of the EGF receptor (by external or internal pathways). We have examined here the significance of such transactivation in brown adipocytes. Stimulation of mature brown adipocytes with cirazoline (α{sub 1}-adrenoceptor coupled via G{sub q}), clonidine (α{sub 2} via G{sub i}) or CL316243 (β{sub 3} via G{sub s}) or via β{sub 1}-receptors significantly activated Erk1/2. Pretreatment with the EGF receptor kinase inhibitor AG1478 had, remarkably, no significant effect on Erk1/2 activation induced by any of these adrenergic agonists (although it fully abolished EGF-induced Erk1/2 activation), demonstrating absence of EGF receptor-mediated transactivation. Results with brown preadipocytes (cells in more proliferative states) were not qualitatively different. Joint stimulation of all adrenoceptors with norepinephrine did not result in synergism on Erk1/2 activation. AG1478 action on EGF-stimulated Erk1/2 phosphorylation showed a sharp concentration–response relationship (IC{sub 50} 0.3 µM); a minor apparent effect of AG1478 on norepinephrine-stimulated Erk1/2 phosphorylation showed nonspecific kinetics, implying caution in interpretation of partial effects of AG1478 as reported in other systems. Transactivation of the EGF receptor is clearly not a universal prerequisite for coupling of G-protein coupled receptors to Erk1/2 signalling cascades. - Highlights: • In brown adipocytes, norepinephrine regulates proliferation, apoptosis, differentiation. • EGF receptor transactivation is supposed to mediate GPCR

Protective properties of plasma of burnt and irradiated rats against lethal effect of endotoxins in vivo

Energy Technology Data Exchange (ETDEWEB)

Budagov, R S; Chureyeva, L N

1984-10-01

The purpose of this work was to estimate protective properties of plasma in disease with increased endotoxemia. Burns and acute radiation sickness were used as models of suppression of physiological mechanisms of detoxication. Experiments were performed on male Wistar rats and mice, which received 3rd degree burns over 15% of the body surface, whole body gamma irradiation at 7.5 Gr or both. At 3 hours, 3, 7 and 12 days after the exposure the animals were decapitated and blood collected. The irradiated mice received 0.2 ml endotoxin intraperitoneally, 1.0 ml freshly prepared rat plasma, then the lethality of the mice in 24 hours was observed. It was found that the plasma of intact rats was capable of decreasing the lethal effects of S. typhimurium and E. coli endotoxins in vivo in mice. Deep skin burns, acute radiation sickness and the combined effects of radiation and thermal injury did not change this phenomenon. The plasma of the experimental rats retained the protective properties at various periods of time after the thermal, radiation and combined exposures. The functioning of the humoral detoxication mechanism is radioresistant, indirectly indicating the nonimmunoglobulin nature of endotoxin inactivators. 19 references.

Nanoporous SiO{sub 2}/TiO{sub 2} coating with enhanced interfacial compatibility for orthopedic applications

Energy Technology Data Exchange (ETDEWEB)

Zhao, Xiaobing, E-mail: zhaoxiaobing00@163.com [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Key Laboratory of Inorganic Coating Materials, Chinese Academy of Sciences, Shanghai 200050 (China); Jiangsu Key Laboratory of Materials Surface Science and Technology, Changzhou University, Changzhou 213164 (China); Cao, Hengchun; You, Jing; Cheng, Xingbao [School of Materials Science and Engineering, Changzhou University, Changzhou 213164 (China); Xie, Youtao [Key Laboratory of Inorganic Coating Materials, Chinese Academy of Sciences, Shanghai 200050 (China); Cao, Huiliang [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Liu, Xuanyong, E-mail: xyliu@mail.sic.ac.cn [State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)

2015-11-15

Graphical abstract: - Highlights: • The SiO{sub 2}/TiO{sub 2} coatings were fabricated on the cp-Ti substrates by plasma spraying. • Nanoporous topography was formed on SiO{sub 2}/TiO{sub 2} coating by HF-hydrothermal etching. • The hydrothermal conditions had important effects on the nanoporous topographies. • Nanoporous SiO{sub 2}/TiO{sub 2} coating exhibited enhanced cytocompatibility. - Abstract: Topographic modification in nanoscale is one of the most often used strategies to enhance the interfacial biocompatibility of implant materials. The aim of this work is to produce SiO{sub 2}/TiO{sub 2} coatings with nanoporous structures and favorable biological properties by atmospheric plasma spraying technology and subsequently hydrothermal etching method in hydrogen fluoride solution. The effects of hydrothermal time and temperature on the microstructures and osteoblast behavior of the SiO{sub 2}/TiO{sub 2} coatings were investigated. Results demonstrated that the as-sprayed SiO{sub 2}/TiO{sub 2} coating was mainly composed of rutile and quartz phases. After etching, nanoporous topographies were formed on the surface of the coatings and the hydrothermal parameters had important influences on the size and shape of the pores. The interconnected network pores on the coating surface could only produce at the appropriate hydrothermal conditions (the hydrothermal time and temperature were 60 min and 100 °C, respectively). Compared to TiO{sub 2} and SiO{sub 2}/TiO{sub 2} coatings, nanoporous SiO{sub 2}/TiO{sub 2} coatings could enhance osteoblast adhesion and promote cell proliferation. The results suggested the potential application of the porous coatings for enhancing the biological performance of the currently used dental and orthopedic implant materials.

Female Rats are Less Susceptible during Puberty to Lethal Effects of Percutaneous Exposure to VX

Science.gov (United States)

2015-12-17

lethal dose determination for percutaneous exposure to soman and VX in guinea pigs and the effectiveness of decontamination with M291 SDK or SANDIA...di-isopropylamino) ethyl] methyl phosphonthioate) through pig , human and guinea pig skin in vitro, Toxicol. In Vitro 20 (2006) 1532–1536. [6] R... production and transepidermal water loss [TEWL]) change with age [3,14,15]. As reviewed in Ref. [28], the barrier function of the stratum corneum is

Effects of lethal dose of γ-irradiation on intestinal enzymes of the pigeons Columba livia intermedia Strickland

International Nuclear Information System (INIS)

Gadhia, P.K.

1979-01-01

Effect of γ-irradiation with lethal dose (1000 rads) on alkaline phosphatase and glucose-6-phosphatase have been studied in two different regions (duodenum and ileum) of small intestine of pigeons. The enzymes were studied at different intervals like 2, 4, 6 and 8 days after irradiation. The sp. activities of enzyme increased significantly both in duodenum and ileum. However, significant increase in alkaline phosphatase and glucose-6-phosphatase were observed at the 2nd and the 4th days post-irradiation respectively. The increase in enzyme activities may present de novo synthesis of these enzymes after lethal dose of irradiation. The histologic picture revealed that after the 4th day of irradiation, the number of goblet cells increased and after the 6th day crypt-villus system was destroyed completely as compared to sham-irradiated pigeons. (author)

Effects of lethal dose of. gamma. -irradiation on intestinal enzymes of the pigeons Columba livia intermedia Strickland

Energy Technology Data Exchange (ETDEWEB)

Gadhia, P.K. (South Gujarat Univ., Surat (India). Dept. of Biosciences); Shah, V.C. (Gujarat Univ. School of Sciences, Ahmedabad (India))

1979-09-01

Effect of ..gamma..-irradiation with lethal dose (1000 rads) on alkaline phosphatase and glucose-6-phosphatase have been studied in two different regions (duodenum and ileum) of small intestine of pigeons. The enzymes were studied at different intervals like 2, 4, 6 and 8 days after irradiation. The sp. activities of enzyme increased significantly both in duodenum and ileum. However, significant increase in alkaline phosphatase and glucose-6-phosphatase were observed at the 2nd and the 4th days post-irradiation respectively. The increase in enzyme activities may present de novo synthesis of these enzymes after lethal dose of irradiation. The histologic picture revealed that after the 4th day of irradiation, the number of goblet cells increased and after the 6th day crypt-villus system was destroyed completely as compared to sham-irradiated pigeons.

Quantitative aspects of repair of potentially lethal damage in mammalian cells

International Nuclear Information System (INIS)

Iliakis, G.; Pohlit, W.

1979-01-01

Stationary cultures of Ehrlich ascites tumour cells were irradiated with X-rays and then immediately or after a time interval tsub(rep) plated to measure the survival. The increase in survival observed after delayed plating was interpreted as repair of potentially lethal damage. A cybernetic model was used to analyse these data. Three states of damage were assumed for the cells. In state A the cells could grow to macrocolonies, in state B the cells suffered potentially lethal damage and could grow to macrocolonies only if they were allowed to repair the damage and in state C the cells were lethally damaged. A method of deriving the values of the parameters of the model from the experimental data was given. The dependence of the reaction rate constant of the repair potentially lethal damage on the dose D was used to derive a possible mechanism for the production of the shoulder in the dose effect curve. Finally this model was compared with other models of radiation action in living cells. (author)

Swimming speed alteration of Artemia sp. and Brachionus plicatilis as a sub-lethal behavioural end-point for ecotoxicological surveys.

Science.gov (United States)

Garaventa, Francesca; Gambardella, Chiara; Di Fino, Alessio; Pittore, Massimiliano; Faimali, Marco

2010-03-01

In this study, we investigated the possibility to improve a new behavioural bioassay (Swimming Speed Alteration test-SSA test) using larvae of marine cyst-forming organisms: e.g. the brine shrimp Artemia sp. and the rotifer Brachionus plicatilis. Swimming speed was investigated as a behavioural end-point for application in ecotoxicology studies. A first experiment to analyse the linear swimming speed of the two organisms was performed to verify the applicability of the video-camera tracking system, here referred to as Swimming Behavioural Recorder (SBR). A second experiment was performed, exposing organisms to different toxic compounds (zinc pyrithione, Macrotrol MT-200, and Eserine). Swimming speed alteration was analyzed together with mortality. The results of the first experiment indicate that SBR is a suitable tool to detect linear swimming speed of the two organisms, since the values have been obtained in accordance with other studies using the same organisms (3.05 mm s(-1) for Artemia sp. and 0.62 mm s(-1) for B. plicatilis). Toxicity test results clearly indicate that swimming speed of Artemia sp. and B. plicatilis is a valid behavioural end-point to detect stress at sub-lethal toxic substance concentrations. Indeed, alterations in swimming speed have been detected at toxic compound concentrations as low as less then 0.1-5% of their LC(50) values. In conclusion, the SSA test with B. plicatilis and Artemia sp. can be a good behavioural integrated output for application in marine ecotoxicology and environmental monitoring programs.

Phase evolution and its effect on magnetic properties of Nd sub 6 sub 0 Al sub 1 sub 0 Fe sub 2 sub 0 Co sub 1 sub 0 bulk metallic glass

CERN Document Server

Lei Xia; Pan, M X; Zhao, D Q; Wang, W H; Dong, Y D

2003-01-01

The thermal stability of nanocrystalline clusters, the phase evolution, and their effects on magnetic properties were studied for as-cast Nd sub 6 sub 0 Al sub 1 sub 0 Fe sub 2 sub 0 Co sub 1 sub 0 alloy using differential scanning calorimetry curves, x-ray diffraction patterns, scanning electron microscopy, and high-resolution transition electron microscopy. Thermomagnetic curves and hysteresis loops of the bulk metallic glass were measured during the annealing process. The high thermostability of the hard magnetic properties of the samples observed is attributed to the stability of the nanocrystalline clusters upon annealing, while the slight enhancement in the magnetization is due to the precipitation of some Nd-rich metastable phases. The mechanism of thermostability of the nanocrystalline clusters and the formation of the metastable phases are discussed.

Effect of pelletization pressure on structural properties and critical current hysteresis of ceramic superconducting Bi sub 1 sub . sub 7 Pb sub 0 sub . sub 3 Sr sub 2 Ca sub 2 Cu sub 3 O sub y

CERN Document Server

Tepe, M; Abukay, D

2003-01-01

The effect of pelletization pressures on structural properties and critical current hysteresis of Bi sub 1 sub . sub 7 Pb sub 0 sub . sub 3 Sr sub 2 Ca sub 2 Cu sub 3 O sub y samples was investigated. The samples used in this study were prepared by classical solid-state reaction at the pressures from 100 up to 500 MPa. The obtained samples were characterized by resistance vs. temperature, (R-T), critical current density vs. applied magnetic field, (J sub c -H), material density vs. pressure, (rho-P), XRD, SEM, and EDAX. The results of this study showed that the quality of electrical and structural properties of Bi-2223 bulk superconductors strongly depends on the pelletization pressure. Pressing of bulk samples at 400 MPa produces textured grain alignment and associates microstructural modifications in order to enhance flux pinning and thus increases current carrying capacities. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

Pancreatic cancer stromal biology and therapy

Science.gov (United States)

Xie, Dacheng; Xie, Keping

2015-01-01

Pancreatic cancer is one of the most lethal malignancies. Significant progresses have been made in understanding of pancreatic cancer pathogenesis, including appreciation of precursor lesions or premalignant pancreatic intraepithelial neoplasia (PanINs), description of sequential transformation from normal pancreatic tissue to invasive pancreatic cancer and identification of major genetic and epigenetic events and the biological impact of those events on malignant behavior. However, the currently used therapeutic strategies targeting tumor epithelial cells, which are potent in cell culture and animal models, have not been successful in the clinic. Presumably, therapeutic resistance of pancreatic cancer is at least in part due to its drastic desmoplasis, which is a defining hallmark for and circumstantially contributes to pancreatic cancer development and progression. Improved understanding of the dynamic interaction between cancer cells and the stroma is important to better understanding pancreatic cancer biology and to designing effective intervention strategies. This review focuses on the origination, evolution and disruption of stromal molecular and cellular components in pancreatic cancer, and their biological effects on pancreatic cancer pathogenesis. PMID:26114155

[Gunshot wounds caused by non-lethal ammunition on the porcine model post-mortem].

Science.gov (United States)

Jabrocký, Peter; Pivko, Juraj; Vondráková, Mária; Tažký, Boris

2013-10-01

In this article we focus on the effects of so called non-lethal ammunition. We studied possible mechanism of firearm injury formation as a consequence of using firearm on the body, to present a more comprehensive material in wound ballistics. We pointed out possible actions of a projectile causes on human, respectively other animal organisms, as well as to a manner in which an injury is caused by rifles or shotguns using non-lethal ammunition with rubber projectiles. In the experiment, we have focused on macroscopic analysis of the tissue penetrated by a rubber projectile fired from a long firearm and pump-action shotgun while focusing on the anatomical-morphological analysis of entry wounds to determine the effectiveness respectively, the wounding potential of the projectile. The results of the experiment based on the macroscopic analysis of entry wounds, cavities and exit wounds, show that when a rubber projectile penetrates the body it causes loss of the tissue (i.e. the minus effect) and mechanical disruption of the tissue similar to lethal projectile. Based on the measures and ballistic computations we concluded that in specific cases, like for example in a close range hit, a penetration of vital organs can cause serious or even lethal injuries.

The potential of TiO<sub>2sub> nanoparticles as carriers for cadmium uptake in Lumbriculus variegatus and Daphnia magna

DEFF Research Database (Denmark)

Hartmann, Nanna Isabella Bloch; Legros, Samuel; Von der Kammer, Frank

2012-01-01

variegatus, was investigated both in the absence and presence of titanium dioxide (TiO2) nanoparticles (P25 Evonic Degussa, d: 30nm). The uptake of cadmium in sub-lethal concentrations was also studied in the absence and presence of 2mg/L TiO2 nanoparticles. Formation of larger nanoparticles aggregates...

Exchange bias training effect in phase separated polycrystalline Sm{sub 0.1}Ca{sub 0.7}Sr{sub 0.2}MnO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Markovich, V., E-mail: markoviv@bgu.ac.il [Department of Physics, Ben-Gurion University of the Negev, 84105, Beer-Sheva (Israel); Fita, I.; Wisniewski, A.; Puzniak, R. [Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, 02-668, Warsaw (Poland); Martin, C. [Laboratoire CRISMAT, UMR 6508, ISMRA, 14050, Caen Cedex (France); Jung, G. [Department of Physics, Ben-Gurion University of the Negev, 84105, Beer-Sheva (Israel); Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, 02-668, Warsaw (Poland); Gorodetsky, G. [Department of Physics, Ben-Gurion University of the Negev, 84105, Beer-Sheva (Israel)

2016-12-01

Magnetic properties of antiferromagnetic (AFM) electron doped manganite Sm{sub 0.1}Ca{sub 0.7}Sr{sub 0.2}MnO{sub 3} have been investigated, focusing mainly on the exchange bias (EB) effect and associated training effect. The studied compound exhibits the ground state with heterogeneous spin configuration, consisting of the C-type antiferromagnetic phase with the Néel temperature T{sub N-C} ≈ 120 K, the G-AFM phase with the Néel temperature T{sub N-G} ≈ 60 K, and ferromagnetic-like phase with a very weak spontaneous magnetic moment. Measurements of hysteresis loops have shown that the exchange bias field monotonously decreases with increasing temperature and vanishes above 40 K, while the coercivity disappears only above 70 K. The temperature variation of the exchange bias field has been successfully described by an exponential decay form. The stability of EB has been evaluated in the studies of the training effect, which has been discussed in the frame of the spin relaxation model, elucidating the important role of the AFM domain rearrangement at the interface. The complex phase separation and possible contributions from different interfaces between coexisting magnetic phases to the EB effect have also been discussed. - Highlights: • Sm{sub 0.1}Ca{sub 0.7}Sr{sub 0.2}MnO{sub 3} exhibits exchange bias (EB) effect at low temperatures T < 40 K. • The EB effect is associated with the phase separation and the presence of FM clusters as well as the G- and C-type AFM phases. • The training effect (TE) has been discussed in the frame of the spin relaxation model. • The TE is relatively small, indicating that AFM moment configuration is almost frozen during the magnetization reversal.

Deterioration in brain and heart functions following a single sub-lethal (0.8 LCt50) inhalation exposure of rats to sarin vapor:

International Nuclear Information System (INIS)

Allon, N.; Chapman, S.; Egoz, I.; Rabinovitz, I.; Kapon, J.; Weissman, B.A.; Yacov, G.; Bloch-Shilderman, E.; Grauer, E.

2011-01-01

The main injuries among victims of the terrorist act in the Tokyo subway resulted from sub-lethal inhalation and whole body exposure to sarin vapor. In order to study the long term effects of such exposure and to simulate these conditions, freely moving rats were exposed to sarin vapor (27.2 ± 1.7 μg/l) for 10 min. About 50% of the rats showed no overt symptoms and the rest had mild to moderate clinical symptoms that subsided within 4 h following exposure. A reduction of weight was noted during the first 3 days with full recovery on the 4th day. Rat's heart was challenged with epinephrine 1 and 6 months post exposure. A significant reduction in the threshold for epinephrine-induced arrhythmia (EPIA) was noted in rats exposed to sarin. A time dependent increase in the kD and Bmax values of muscarinic auto receptors (M2) was recorded in the rat's cortex and striatum. No changes were recorded in the rats' brain trans locator protein (TSPO) levels, concomitant with no observed changes in the animals' performance in A Morris water maze test. A significant increase in open field activity was noted 6 months following exposure to sarin vapor as well as a significant decrease in prostaglandin E 2 (PGE 2 ) production in the brain. It is speculated that down regulation of the M2 auto receptor function, caused hyper reactivity of the cholinergic system which leads to the changes described above. The continuous reduction in M2 auto-receptor system through an unknown mechanism may be the cause for long lasting decline in sarin-exposed casualties' health.

Potentially lethal damage and its repair

International Nuclear Information System (INIS)

Utsumi, Hiroshi

1989-01-01

Two forms termed fast-and slow-potentially lethal lethal damage (PLD) are introduced and discussed. The effect on the survival of x-irradiated Chinese hamster cells (V79) of two different post-treatments is examined in plateau- and in log-phases of growth. The postirradiation treatments used : a) incubation in hypertonic solution, and b) incubation in conditioned medium obtained from plateau-phase. Similar reduction in survival was caused by postirradiation treatment with hypertonic phosphate buffered saline, and similar increased in survival was effected by treatment in conditioned medium in plateau- and in log-phases cells. However, repair of PLD sensitive to hypertonic treatment was faster (half time, 5-10 min)(f-PLD repair) and independent from the repair of PLD (half time, 1-2 hour)(s-PLD repair) observed in conditioned medium. The results indicate the induction of two forms of PLD by radiation. Induction of both PLD was found to decrease with increasing LET of the radiation used. Identification of the molecular processes underlying repair and fixation of PLD is a task of particular interest, since it may allow replacement of a phenomenological definition with a molecular definition. Evidence is reviewed indicating the DNA double strand breaks (directly or indirectly induced) may be the DNA lesions underlying PLD. (author)

Synthesis of Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} via combustion route: Effects of Al{sub 2}O{sub 3} nanoparticles on superconducting properties

Energy Technology Data Exchange (ETDEWEB)

Mohd Suan, Mohd Shahadan, E-mail: mohdshahadan@utem.edu.my [Department of Engineering Materials, Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, 76100 Durian Tunggal, Melaka (Malaysia); Johan, Mohd Rafie [Nanomaterial Engineering Research Group, Advanced Materials Research Laboratory, Department of Mechanical Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2017-02-01

Combustion reaction was used to synthesis Al{sub 2}O{sub 3} nanoparticles embedded Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} simultaneously. The effects of Al{sub 2}O{sub 3} nanoparticles with nominal molar mass (x{sub mol}) of 0.02, 0.04, 0.06, 0.08 and 0.10 towards the critical current density J{sub C} of Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} were verified by magnetic measurement. Resulted XRD patterns revealed that the calcined samples consist of pure Al{sub 2}O{sub 3} and Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} phases which had been confirmed by EDX results. The SEM images showed that Al{sub 2}O{sub 3} nanoparticles (~10 nm) were distributed in polycrystalline YBa{sub 2}Cu{sub 3}O{sub 7-δ} grains and grain boundaries. The presence of higher concentration of Al{sub 2}O{sub 3} nanoparticles has developed Al{sup 3+} rich spots which diffused within the YBa{sub 2}Cu{sub 3}O{sub 7-δ} superconducting matrix to form Y{sub 1-x}Al{sub x}Ba{sub 2}Cu{sub 3}O{sub 7-δ} and was confirmed by EDX analysis. The samples were electrically superconducting at temperature above 85 K as measured by using standard four-probe technique. The magnetic field (H) dependent magnetization (M), M-H hysteresis loops measured at 77 K for x{sub mol}≤0.06 samples are significantly improved attributed to the increase of trapped fluxes in the samples. Remarkable increase of magnetic J{sub C} (H) in Al{sub 2}O{sub 3} nanoparticles added samples compared to the as prepared polycrystalline YBa{sub 2}Cu{sub 3}O{sub 7-δ} sample indicating strong pinning effect. It is suggested that well-distributed Al{sub 2}O{sub 3} nanoparticles in the polycrystalline YBa{sub 2}Cu{sub 3}O{sub 7-δ} matrix achieved via auto-combustion reaction has efficiently pin the magnetic vortex. The magnetic J{sub C} was optimized to ~6 kAcm{sup -2} in x{sub mol}=0.06 sample. On the other hand, insignificant magnetic J{sub C} improvement in x{sub mol}≥0.08 samples is probably resulted from the

Lethal and sublethal effects of azadirachtin and cypermethrin on Habrobracon hebetor (Hymenoptera: Braconidae).

Science.gov (United States)

Abedi, Zahra; Saber, Moosa; Gharekhani, Gholamhossein; Mehrvar, Ali; Kamita, Shizuo George

2014-04-01

Habrobracon hebetor Say is an ectoparasitoid of larval stage of various lepidopteran pests. Lethal and sublethal effects of azadirachtin and cypermethrin were evaluated on adult and preimaginal stages of H. hebetor under laboratory conditions. Contact exposure bioassays with adults indicated that the lethal concentration (LC50) of two commercial azadirachtin-containing formulations, NeemGuard and BioNeem, were 43.5 and 10.2 microg a.i./ml, respectively. The LC50 of cypermethrin was 5.4 microg a.i./ml. When larval stage of H. hebetor was exposed to these insecticides with a field recommended concentration of NeemGuard, BioNeem, or cypermethrin by a dip protocol, the emergence rate was reduced by 39.0, 36.6, and 97.6%, respectively. To assay the sublethal effects of these insecticides, adult wasps were exposed to an LC30 concentration of the insecticides, and then demographic parameters of the surviving wasps were determined. Fecundity, fertility, and parameters including the intrinsic rate of increase (r(m)) were affected negatively. The r(m) values following exposure to NeemGuard, BioNeem, cypermethrin, or mock treatment were 0.143, 0.149, 0.160, and 0.179, respectively, female offspring per female per day, respectively. The current study showed that cypermethrin had more acute toxicity on larval and adult stages of H. hebetor compared with azadirachin. The commercial formulations of azadirachtin and cypermethrin negatively affected most of the life table parameters of the parasitoid. Semifield and field studies are needed for obtaining more applicable results on combining H. hebetor and the tested insecticides for an integrated pest management-based strategy for crop protection.

Biological H{sub 2} from syngas and from H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

Weaver, P.; Maness, P.C.; Markov, S.; Martin, S. [National Renewable Energy Lab., Golden, CO (United States)

1996-10-01

The two stand-alone objectives of the research are to economically produce neat H{sub 2} in the near term from biomass (thermally gasified to syngas) and in the mid term from H{sub 2}O using cyanobacteria or algae with an oxygen-tolerant bacterial hydrogenase. Photosynthetic bacteria have four different terminal enzymes that mediate their H{sub 2} metabolisms-nitrogenase, uptake hydrogenase, fermentative hydrogenase, and carbon monoxide-linked hydrogenase. Each has been microbiologically and biochemically examined for their potential to specifically generate H{sub 2} in large-scale processes. Based on measurements of maximal activities, stabilities, energy requirements, equilibria, and partial pressures of the H{sub 2} producing reactions, the CO-linked hydrogenase is easily the most suited for practical applications. The enzyme mediates H{sub 2} production from CO at rates up to 1.5 mmol/min/g cell dry weight at near ambient temperature and pressure. Hydrogen can be produced and evolved at linear rates up to at least 2 atmospheres of partial pressure (100% CO). The rate-limiting step with high cell density suspensions is the mass transfer of CO into the aqueous phase. Bioreactor designs have been examined which enhance the mass transfer. Hollow-fiber bioreactors with bacterial cells immobilized on the fiber surfaces evolve H{sub 2} at ambient pressure at rates of about 0.3-0.7 mmol/min/g cdw. One such reactor has been producing H{sub 2} from CO continuously for 9 months with only occasional changes of liquid medium. A trickle-filter reactor with bacteria immobilized on beads removed from a bulk water phase and a pumped-bubble coil reactor with bacteria in suspension are also being examined.

Ingestion of marine plastic debris by green turtle(Chelonia mydas) in davao gulf, Mindanao, Philippines

NARCIS (Netherlands)

Abreo, Neil A.S.; Macusi, Edison D.; Blatchley, Darrell D.

2016-01-01

Marine plastic debris is a global problem that is threatening marine biodiversity. Different marine organisms have been exposed to the lethal and sub-lethal effects of this problem. Sub-lethal effects include reduced fitness due to reduced feeding, reduced reproductive output, limb amputation,

Chemoradiotherapy and molecular biology

International Nuclear Information System (INIS)

Hasegawa, Masatoshi; Mitsuhashi, Norio; Niibe, Hideo

2000-01-01

The current status of chemoradiotherapy was reviewed from the standpoint of molecular biology. Chemoradiotherapy was conducted to achieve systemic tumor control, to intensify the response to irradiation, and to reduce adverse reactions. The mechanisms of the efficacy of chemoradiotherapy were: modification of dose-response relationships, inhibition of tumor cell recovery from sublethal damage or potential lethal damage, effects on cell dynamics and the cell cycle, improvement of blood flow or reoxygenation, recruitment, improvement of drug uptake, increased cell damage. Cell death (necrosis and apoptosis) and cancer-related genes were described, as the essential points, because they are involved in the response to chemoradiotherapy. Cisplatin (platinum compound), 5-fluorouracil, etoposide, and taxoid (paclitaxel, docetaxel) were the principal anticancer agents used for chemoradiotherapy, and they enhanced the effects of irradiation. However, even when good responses or synergism between anticancer drug and radiotherapy was observed in in vitro studies, there was little therapeutic advantage clinically. Data from in vitro and in vivo studies should be collected and systemized, and ''molecular biology in chemotherapy'' that can be applied clinically may become established. (K.H.)

Magnetorefractive effect in the La{sub 1−x}K{sub x}MnO{sub 3} thin films grown by MOCVD

Energy Technology Data Exchange (ETDEWEB)

Sukhorukov, Yu.P., E-mail: suhorukov@imp.uran.ru [Institute of Metal Physics, Ural Division of RAS, 620990 Ekaterinburg (Russian Federation); Telegin, A.V. [Institute of Metal Physics, Ural Division of RAS, 620990 Ekaterinburg (Russian Federation); Bessonov, V.D. [Institute of Metal Physics, Ural Division of RAS, 620990 Ekaterinburg (Russian Federation); University of Bialystok, 15-424 Bialystok (Poland); Gan’shina, E.A.; Kaul’, A.R.; Korsakov, I.E.; Perov, N.S.; Fetisov, L.Yu. [Faculty of Physics, Moscow State University, Moscow 119991 (Russian Federation); Yurasov, A.N. [Moscow State Technical University of Radioengineering, Electronics and Automation, 119454 Moscow (Russian Federation)

2014-10-01

Thin epitaxial La{sub 1−x}K{sub x}MnO{sub 3} films were grown using two-stage procedure. Influence of substitution of La{sup 3+} ions with K{sup +} ions on the optical and electrical properties of La{sub 1−x}K{sub x}MnO{sub 3} films (x=0.05, 0.10, 0.15 i 0.18) has been studied in detail. A noticeable magnetorefractive effect in the films under study was detected in the infrared range. Magnetorefractive effect as well as transverse magneto-optical Kerr effect and magnetoresistance have the maximum in optimally doped sample with x=0.18 corresponding to the highest Curie temperature. The experimental data for compositions close to optimally doped films are in good agreement with the data calculated in the framework of a theory developed for manganites. The resonance-like contribution to magnetoreflection spectra of manganite films has been observed in the vicinity of the phonon bands. It is shown that magnetic and charge inhomogeneities strongly influence on the magneto-optical effects in films. Thin films of La{sub 1−x}K{sub x}MnO{sub 3} with the large values of Kerr and magnetorefractive effect are promising magneto-optical material in the infrared range. - Highlights: • Giant magnetorefractive effect was obtained in La{sub 1−x}K{sub x}MnO{sub 3} films in the infrared. • Inhomogeneity as well as doping level strongly influences the value of magnetorefractive effect. • Resonance-like bands have been observed in the magnetoreflection spectra of the films. • The obtained experimental data can be explained in the framework of the MRE theory.

Cardiac-specific catalase overexpression rescues anthrax lethal toxin-induced cardiac contractile dysfunction: role of oxidative stress and autophagy.

Science.gov (United States)

Kandadi, Machender R; Yu, Xuejun; Frankel, Arthur E; Ren, Jun

2012-11-07

Lethal and edema toxins secreted by Bacillus anthracis during anthrax infection were found to incite serious cardiovascular complications. However, the underlying mechanisms in anthrax lethal toxin-induced cardiac anomalies remain unknown. This study was designed to evaluate the impact of antioxidant enzyme catalase in anthrax lethal toxin-induced cardiomyocyte contractile dysfunction. Wild type (WT) and cardiac-specific catalase overexpression mice were challenged with lethal toxin (2 μg/g, intraperotineally (i.p.)). Cardiomyocyte contractile and intracellular Ca(2+) properties were assessed 18 h later using an IonOptix edge-detection system. Proteasome function was assessed using chymotrypsin-like and caspase-like activities. GFP-LC3 puncta and Western blot analysis were used to evaluate autophagy and protein ubiquitination. Lethal toxin exposure suppressed cardiomyocyte contractile function (suppressed peak shortening, maximal velocity of shortening/re-lengthening, prolonged duration of shortening/re-lengthening, and impaired intracellular Ca(2+) handling), the effects of which were alleviated by catalase. In addition, lethal toxin triggered autophagy, mitochondrial and ubiquitin-proteasome defects, the effects of which were mitigated by catalase. Pretreatment of cardiomyocytes from catalase mice with the autophagy inducer rapamycin significantly attenuated or ablated catalase-offered protection against lethal toxin-induced cardiomyocyte dysfunction. On the other hand, the autophagy inhibitor 3-MA ablated or significantly attenuated lethal toxin-induced cardiomyocyte contractile anomalies. Our results suggest that catalase is protective against anthrax lethal toxin-induced cardiomyocyte contractile and intracellular Ca(2+) anomalies, possibly through regulation of autophagy and mitochondrial function.

Room-temperature multiferroic and magnetocapacitance effects in M-type hexaferrite BaFe{sub 10.2}Sc{sub 1.8}O{sub 19}

Energy Technology Data Exchange (ETDEWEB)

Tang, Rujun, E-mail: tangrj@suda.edu.cn, E-mail: yanghao@nuaa.edu.cn; Zhou, Hao; You, Wenlong [Jiangsu Key Laboratory of Thin Films, College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006 (China); Yang, Hao, E-mail: tangrj@suda.edu.cn, E-mail: yanghao@nuaa.edu.cn [College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 211106 (China)

2016-08-22

The room-temperature multiferroic and magnetocapacitance (MC) effects of polycrystalline M-type hexaferrite BaFe{sub 10.2}Sc{sub 1.8}O{sub 19} have been investigated. The results show that the magnetic moments of insulating BaFe{sub 10.2}Sc{sub 1.8}O{sub 19} can be manipulated by the electric field at room temperature, indicating the existence of magnetoelectric coupling. Moreover, large MC effects are also observed around the room temperature. A frequency dependence analysis shows that the Maxwell-Wagner type magnetoresistance effect is the dominant mechanism for MC effects at low frequencies. Both the magnetoelectric-type and non-magnetoelectric-type spin-phonon couplings contribute to the MC effects at high frequencies with the former being the dominant mechanism. The above results show that the hexaferrite BaFe{sub 10.2}Sc{sub 1.8}O{sub 19} is a room-temperature multiferroic material that can be potentially used in magnetoelectric devices.

Effects of current stressing on the p-Bi{sub 2}Te{sub 3}/Sn interfacial reactions

Energy Technology Data Exchange (ETDEWEB)

Chan, Hsing-Ting; Lin, Chih-Fan [Department of Chemical Engineering, National Chung Hsing University, Taichung 402, Taiwan (China); Yen, Yee-Wen [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan (China); Chen, Chih-Ming, E-mail: chencm@nchu.edu.tw [Department of Chemical Engineering, National Chung Hsing University, Taichung 402, Taiwan (China)

2016-05-25

The Sn/p-Bi{sub 2}Te{sub 3}/Sn sandwich-type sample was current stressed with a density of 150 A/cm{sup 2} to investigate the effects of current stressing on the p-Bi{sub 2}Te{sub 3}/Sn interfacial reactions. Asymmetrical heating phenomenon was observed at the anodic Sn/p-Bi{sub 2}Te{sub 3} (50 °C) and cathodic p-Bi{sub 2}Te{sub 3}/Sn (120 °C) interfaces due to the Peltier effect. Besides the Peltier effect, the electromigration effect also influenced the growth of the SnTe phase and therefore polarity growth behavior was observed at the two interfaces. The growth of the SnTe phase at the cathodic p-Bi{sub 2}Te{sub 3}/Sn interface was accelerated because Peltier and electromigration effects drove more Sn atoms (dominant diffusion species) for the phase growth. By measuring the electromigration-induced atomic flux of Sn, the product of diffusivity and effective charge number (D × z*) was calculated to be 6.3 × 10{sup −9} cm{sup 2} s{sup −1} at 120 °C. - Highlights: • Sn/p-Bi{sub 2}Te{sub 3}/Sn sandwich-type sample is current stressed with a density of 150 A/cm{sup 2}. • Passage of an electric current induces Peltier and electromigration effects. • Peltier effect causes asymmetrical heating at the anode and cathode interfaces. • Both effects accelerate the SnTe growth at the cathode interface. • Sn is the dominant diffusion species identified by a marker experiment.

Effects of β-arabinofuranosyladenine on the growth and repair of potentially lethal damage in Ehrlich ascites tumor cells

International Nuclear Information System (INIS)

Iliakis, G.

1980-01-01

β-D-Arabinofuranosyladenine (β-araA) inhibit the growth of Ehrlich ascites tumor cells by selective inhibition of DNA polymerases. RNA and protein synthesis are not significantly affected. Addition of β-araA to the cells after irradiation resulted in a concentration-dependent decrease in survival, presumably due to the inhibition of the repair of potentially lethal damage. Since β-araA selectively inhibits DNA polymerases it is suggested that repair of potentially lethal damage involves steps at the DNA level which require some polymerization. These repair steps take place in the DNA with a velocity comparable to that of the repair of potentially lethal damage. The inhibition of the repair of potentially lethal damage by β-araA was modified by the addition of deoxyadenosine; this supports the finding that β-araA acts competitively against dATP at the molecular level. The inhibition of the repair of potentially lethal damage by β-araA, which is partly reversible, resulted in a concentration-dependent modification of the survival curve. At low concentrations of β-araA a dose-modifying decrease in survival was observed. At higher concentrations (more than 12 μM) the decrease in survival resulted in a decrease of the shoulder width of the survival curve. Eventually an exponential curve was obtained. We suggest therefore that the shoulder of the survival curve results from some repair or potentially lethal damage. Preliminary information has been obtained on the time course of this repair

Transverse peltier effect in Pb-Bi{sub 2}Te{sub 3} multilayer structures

Energy Technology Data Exchange (ETDEWEB)

Reitmaier, Christina; Walther, Franziska; Kyarad, Amir; Lengfellner, Hans [University of Regensburg (Germany)

2009-07-01

Metal-semiconductor multilayer structures show, according to model calculations, large anisotropy in their electrical and thermal transport properties. Multilayer stacks consisting of alternating layers of Pb and n-type Bi{sub 2}Te{sub 3} and prepared by a heating procedure displayed large thermoelectric anisotropy up to {delta}S{approx}200 {mu} V/K, depending on the thickness ratio p=d{sub BiTe}/d{sub Pb}, where d{sub BiTe} and d{sub Pb} are the thicknesses of Bi{sub 2}Te{sub 3} and Pb layers, respectively. From multilayer stacks, tilted samples with layers inclined with respect to the sample surface where obtained by cutting stacks obliquely to the stack axis. Non-zero off-diagonal elements in the Seebeck-tensor describing the thermopower of tilted samples allow for the occurance of a transverse Peltier effect. Experimental results demonstrate cooling by the transverse Peltier effect and are compared to model calculations.

Structural Biology Insight for the Design of Sub-type Selective Aurora Kinase Inhibitors.

Science.gov (United States)

Sarvagalla, Sailu; Coumar, Mohane Selvaraj

2015-01-01

Aurora kinase A, B and C, are key regulators of mitosis and are over expressed in many of the human cancers, making them an ideal drug target for cancer chemotherapy. Currently, over a dozen of Aurora kinase inhibitors are in various phases of clinical development. The majority of the inhibitors (VX-680/MK-0457, PHA-739358, CYC116, SNS-314, AMG 900, AT-9283, SCH- 1473759, ABT-348, PF-03814735, R-763/AS-703569, KW-2449 and TAK-901) are pan-selective (isoform non-selective) and few are Aurora A (MLN8054, MLN8237, VX-689/MK5108 and ENMD 2076) and Aurora B (AZD1152 and GSK1070916) sub-type selective. Despite the intensive research efforts in the past decade, no Aurora kinase inhibitor has reached the market. Recent evidence suggests that the sub-type selective Aurora kinase A inhibitor could possess advantages over pan-selective Aurora inhibitors, by avoiding Aurora B mediated neutropenia. However, sub-type selective Aurora kinase A inhibitor design is very challenging due to the similarity in the active site among the isoforms. Structural biology and computational aspects pertaining to the design of Aurora kinase inhibitors were analyzed and found that a possible means to develop sub-type selective inhibitor is by targeting Aurora A specific residues (Leu215, Thr217 and Arg220) or Aurora B specific residues (Arg159, Glu161 and Lys164), near the solvent exposed region of the protein. Particularly, a useful strategy for the design of sub-type selective Aurora A inhibitor could be by targeting Thr217 residue as in the case of MLN8054. Further preclinical and clinical studies with the sub-type selective Aurora inhibitors could help bring them to the market for the treatment of cancer.

Toxicity bioassay and effects of sub-lethal exposure of malathion on ...

African Journals Online (AJOL)

Ksu-network

2012-04-26

Apr 26, 2012 ... glutamate pyruvic transaminase. Non-target animals including fish are greatly affected by the indiscriminate use of these pesticides. Fish appear to posses the same biochemical pathways to deal with the toxic effects of endogenous and exogenous agents as mammalian species does (Lackner, 1998).

Mining of lethal recessive genetic variation in Danish cattle

DEFF Research Database (Denmark)

Das, Ashutosh

2015-01-01

in fertility. The primary objective of this PhD projekt was to identify recessive lethal gentic variants in the main Danish dairy cattle breed. Holstein-Friesian utilzing next generation sequencing (NGS) data. This study shows a potential for the use of the NGS-based reverse genetic approach in identifying...... lethal or semi-lethal recessive gentic variation...

Lethal and sublethal effects of azadirachtin on the bumblebee Bombus terrestris (Hymenoptera: Apidae).

Science.gov (United States)

Barbosa, Wagner Faria; De Meyer, Laurens; Guedes, Raul Narciso C; Smagghe, Guy

2015-01-01

Azadirachtin is a biorational insecticide commonly reported as selective to a range of beneficial insects. Nonetheless, only few studies have been carried out with pollinators, usually emphasizing the honeybee Apis mellifera and neglecting other important pollinator species such as the bumblebee Bombus terrestris. Here, lethal and sublethal effects of azadirachtin were studied on B. terrestris via oral exposure in the laboratory to bring out the potential risks of the compound to this important pollinator. The compound was tested at different concentrations above and below the maximum concentration that is used in the field (32 mg L(-1)). As most important results, azadirachtin repelled bumblebee workers in a concentration-dependent manner. The median repellence concentration (RC50) was estimated as 504 mg L(-1). Microcolonies chronically exposed to azadirachtin via treated sugar water during 11 weeks in the laboratory exhibited a high mortality ranging from 32 to 100 % with a range of concentrations between 3.2 and 320 mg L(-1). Moreover, no reproduction was scored when concentrations were higher than 3.2 mg L(-1). At 3.2 mg L(-1), azadirachtin significantly inhibited the egg-laying and, consequently, the production of drones during 6 weeks. Ovarian length decreased with the increase of the azadirachtin concentration. When azadirachtin was tested under an experimental setup in the laboratory where bumblebees need to forage for food, the sublethal effects were stronger as the numbers of drones were reduced already with a concentration of 0.64 mg L(-1). Besides, a negative correlation was found between the body mass of male offspring and azadirachtin concentration. In conclusion, our results as performed in the laboratory demonstrated that azadirachtin can affect B. terrestris with a range of sublethal effects. Taking into account that sublethal effects are as important as lethal effects for the development and survival of the colonies of B. terrestris

Repair of potentially lethal radiation damage: comparison of neutron and x-ray RBE and implications for radiation therapy

International Nuclear Information System (INIS)

Hall, E.J.; Kraljevic, U.

1976-01-01

Experiments with Chinese hamster cells have shown that neutron irradiation does not result in repair of potentially lethal damage (PLD), i.e., that which can be influenced by changes in environmental conditions following irradiation. Since PLD is presumed to be repaired in tumors but not in normal tissues, this absence of differential sparing of tumor cells relative to normal tissues--a feature characteristic of irradiation with x rays--represents an advantage of neutrons in addition to their reduced oxygen effect. At a given dose, the difference in relative biological effectiveness (RBE) between tumors and normal tissues corresponds to a 5 percent increase in tumor dose with no concomitant increase in dose to normal tissues, which could be significant in cancer therapy

Synthesis, formulation of nucleo-equipment and biological studies of the {sup 99m} Tc-MAG{sub 3}; Sintesis, formulacion de nucleo-equipos y estudios biologicos de la {sup 99m} Tc-MAG{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Reyes H, L; Lezama C, J; Ferro F, G

1991-10-15

Technetium-99m-mercaptoacetyl glycylglycylglycine ({sup 99m}Tc-MAG{sub 3}) is introduced to replace o-iodohippurate (OIH) for renal function studies. In this paper we present the synthesis, labelling and biological evaluation of {sup 99m}Tc- MAG{sub 3} prepared in our laboratory. The precursor s-benzoyl-mercaptoacetyl glycyl glycylglycine (Bz-MAG{sub 3} ) was synthesized by condensation of glycylglycylglycine with chloroacetyl chloride to obtain chloroacetyl glycylglycylglycine and this product was condensate with sodium thiobenzoate. The Bz-MAG{sub 3} was characterized by IR and NMR. The labelling with {sup 99m}Tc was carried out at pH 9.0 using stannous chloride as a reducing agent with heating to boiling for 15 min. The benzoyl group is lost in this step, forming {sup 99m}Tc-MAG{sub 3} complex with radiochemical purity of 99%. The biodistribution properties were evaluated in mice and a rapid renal extraction was apparent at the 10 minutes value (51.65% of the injected dose). The radiotracer was administered to 5 patients showing a good biological behavior. Based on these results, the {sup 99m}Tc-MAG{sub 3} is expected to have widespread clinical utility in Mexico. (Author)

Impulsivity, aggression and brain structure in high and low lethality suicide attempters with borderline personality disorder.

Science.gov (United States)

Soloff, Paul; White, Richard; Diwadkar, Vaibhav A

2014-06-30

Impulsivity and aggressiveness are trait dispositions associated with the vulnerability to suicidal behavior across diagnoses. They are associated with structural and functional abnormalities in brain networks involved in regulation of mood, impulse and behavior. They are also core characteristics of borderline personality disorder (BPD), a disorder defined, in part, by recurrent suicidal behavior. We assessed the relationships between personality traits, brain structure and lethality of suicide attempts in 51 BPD attempters using multiple regression analyses on structural MRI data. BPD was diagnosed by the Diagnostic Interview for Borderline Patients-revised, impulsivity by the Barratt Impulsiveness Scale (BIS), aggression by the Brown-Goodwin Lifetime History of Aggression (LHA), and high lethality by a score of 4 or more on the Lethality Rating Scale (LRS). Sixteen High Lethality attempters were compared to 35 Low Lethality attempters, with no significant differences noted in gender, co-morbidity, childhood abuse, BIS or LHA scores. Degree of medical lethality (LRS) was negatively related to gray matter volumes across multiple fronto-temporal-limbic regions. Effects of impulsivity and aggression on gray matter volumes discriminated High from Low Lethality attempters and differed markedly within lethality groups. Lethality of suicide attempts in BPD may be related to the mediation of these personality traits by specific neural networks. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Low concentrations of metal mixture exposures have adverse effects on selected biomarkers of Xenopus laevis tadpoles

Energy Technology Data Exchange (ETDEWEB)

Yologlu, Ertan, E-mail: ertanyologlu82@gmail.com [Adiyaman University, Faculty of Education, Department of Science Education, 02040 Adiyaman (Turkey); Ozmen, Murat [Inonu University, Laboratory of Environmental Toxicology, Department of Biology, Faculty of Arts & Science, 44280 Malatya (Turkey)

2015-11-15

Highlights: • Selected metal mixtures were evaluated for toxicity of safety limit concentrations. • Xenopus laevis tadpoles were used as model test organism. • Combinations of LC{sub 50} and LC{sub 50}/2 caused 100% lethality for some metals. • Metals did not change metallothionein levels in low concentrations. • Selected enzyme activities showed induction after low concentration exposures. - Abstract: Polluted ecosystems may contain mixtures of metals, such that the combinations of metals, even in low concentrations, may cause adverse effects. In the present study, we focused on toxic effects of mixtures of selected metals, the LC{sub 50} values, and also their safety limit in aquatic systems imposed by the European legislation using a model organism. Xenopus laevis tadpoles were used as test organisms. They were exposed to metals or their combinations due to 96-h LC{sub 50} values. Glutathione S-transferase (GST), glutathione reductase (GR), acetylcholinesterase (AChE), carboxylesterase (CaE), glutathione peroxidase (GPx), and catalase (CAT) levels were evaluated. Metallothionein concentrations were also determined. The LC{sub 50}s for Cd, Pb, and Cu were calculated as 5.81 mg AI/L, 123.05 mg AI/L, and 0.85 mg AI/L, respectively. Low lethality ratios were observed with unary exposure of each metal in lower concentrations. Double or triple combinations of LC{sub 50} and LC{sub 50}/2 concentrations caused 100% lethality with Cd + Cu and Pb + Cd + Cu mixtures, while the Pb + Cu mixture also caused high lethal ratios. The selected enzyme activities were significantly affected by metals or mixtures, and dose-related effects were determined. The metallothionein levels generally increased as related to concentration in unary metals and mixtures. Acceptable limit values of unary metals and mixtures did not significantly change metallothionein levels. The results suggest that oxidative stress-related mechanisms are involved in the toxicity induced by selected

Cell lethality after selective irradiation of the DNA replication fork

International Nuclear Information System (INIS)

Hofer, K.G.; Warters, R.L.

1985-01-01

It has been suggested that nascent DNA located at the DNA replication fork may exhibit enhanced sensitivity to radiation damage. To evaluate this hypothesis, Chinese hamster ovary cells (CHO) were labeled with 125 I-iododeoxyuridine ( 125 IUdR) either in the presence or absence of aphidicolin. Aphidicolin (5 μg/ml) reduced cellular 125 IUdR incorporation to 3-5% of the control value. The residual 125 I incorporation appeared to be restricted to low molecular weight (sub-replicon sized) fragments of DNA which were more sensitive to micrococcal nuclease attack and less sensitive to high salt DNase I digestion than randomly labeled DNA. These findings suggest that DNA replicated in the presence of aphidicolin remains localized at the replication fork adjacent to the nuclear matrix. Based on these observations an attempt was made to compare the lethal consequences of 125 I decays at the replication fork to that of 125 I decays randomly distributed over the entire genome. Regardless of the distribution of decay events, all treatment groups exhibited identical dose-response curves (D 0 : 101 125 I decays/cell). Since differential irradiation of the replication complex did not result in enhanced cell lethality, it can be concluded that neither the nascent DNA nor the protein components (replicative enzymes, nuclear protein matrix) associated with the DNA replication site constitute key radiosensitive targets within the cellular genome. (orig.)

Modeling response of species to microcontaminants: comparative ecotoxicology by (sub)lethal body burdens as a function of species size and partition ratio of chemicals.

Science.gov (United States)

Hendriks, A J

1995-11-01

A model was designed and calibrated with accumulation data to calculate the internal concentrations of microcontaminants in organisms as a function of a few constants and variables. The main factors are the exposure time, the external exposure concentration, the partition ratio of the compound, and the size of the taxon concerned. The model was applied to calculate the lethal and sublethal body burdens of several priority compounds and some major taxa. Estimations were generally confirmed at the order of magnitude level by measured residues and applied doses if available. According to the estimations, most priority compounds chosen were critical for most taxa above internal concentrations of 0.1 mmol.kg-1 wet wt. Trichloromethane, 1,2,4-trichlorobenzene, and hexachlorobenzene were lethal above this level only, whereas other organic microcontaminants affected at least some taxa at lower body burdens. The log(Kow) of the organic compounds ranged from 2.0 to 7.0. Keeping in mind that bioconcentration and -magnification ratios for metals may be quite variable, the lowest critical residues estimated were just below the value of 0.1 mmol.kg-1 wet wt. Here, external concentrations encountered in natural habitats seem to be a promising tool for predictive comparative ecotoxicology. The critical body burdens for plants and invertebrates may have been overestimated due to uncertainty about the parameters. Among the different taxa, however, the fish families chosen (Salmonidae and Cyprinidae) seem to be most sensitive to most compounds. Internal response concentrations of the herbicide atrazine were the lowest in micro- and macrophytes, whereas parathion affected invertebrates at low levels. The database that provided the external response concentrations was also consulted to estimate so-called extrapolation or safety factors. On average, long-term no effect concentrations in water are estimated to be about 10-30 times below short-term median lethal levels. In general, short

Clostridium sordellii lethal toxin kills mice by inducing a major increase in lung vascular permeability.

Science.gov (United States)

Geny, Blandine; Khun, Huot; Fitting, Catherine; Zarantonelli, Leticia; Mazuet, Christelle; Cayet, Nadège; Szatanik, Marek; Prevost, Marie-Christine; Cavaillon, Jean-Marc; Huerre, Michel; Popoff, Michel R

2007-03-01

When intraperitoneally injected into Swiss mice, Clostridium sordellii lethal toxin reproduces the fatal toxic shock syndrome observed in humans and animals after natural infection. This animal model was used to study the mechanism of lethal toxin-induced death. Histopathological and biochemical analyses identified lung and heart as preferential organs targeted by lethal toxin. Massive extravasation of blood fluid in the thoracic cage, resulting from an increase in lung vascular permeability, generated profound modifications such as animal dehydration, increase in hematocrit, hypoxia, and finally, cardiorespiratory failure. Vascular permeability increase induced by lethal toxin resulted from modifications of lung endothelial cells as evidenced by electron microscopy. Immunohistochemical analysis demonstrated that VE-cadherin, a protein participating in intercellular adherens junctions, was redistributed from membrane to cytosol in lung endothelial cells. No major sign of lethal toxin-induced inflammation was observed that could participate in the toxic shock syndrome. The main effect of the lethal toxin is the glucosylation-dependent inactivation of small GTPases, in particular Rac, which is involved in actin polymerization occurring in vivo in lungs leading to E-cadherin junction destabilization. We conclude that the cells most susceptible to lethal toxin are lung vascular endothelial cells, the adherens junctions of which were altered after intoxication.

Potentiation of radiation lethality by Topotecan, a Topoisomerase I inhibitor

International Nuclear Information System (INIS)

Lamond, J.P.; Kinsella, T.J.; Boothman, D.A.

1995-01-01

Purpose/Objective: Topotecan is a water soluble Topoisomerase I (Topo I) inhibitor that has demonstrated antineoplastic activity in phase I/II trials of solid tumors (such as non-small cell lung, small cell lung, ovarian, esophageal and head and neck primaries) and leukemias. We sought to determine (1) if Topotecan potentiated the lethal effects of ionizing radiation, and (2) the characteristics of the synergistic effect. Materials and Methods: Human radioresistant melanoma (U1-Mel) and glioma (D54) cells were grown in Dulbecco's modified Eagle's medium (DME) with 10% fetal calf serum (FCS) until confluence-arrest. Cells were x-irradiated (0-700 cGy) and exposed to various Topotecan concentrations (2-100μM), either before (for 4 hours), during, or after (for 4 hours) irradiation. Appropriate controls were also performed. Survival was determined via colony forming assays. Survival curves were normalized to correct for drug cytotoxicities and variations in initial viable cells plated. In another set of experiments, U1-Mel cells were exposed to 10 μM Topotecan either before, during or after 400 cGy, as described above. A modification of the SDS and KCl assay was used to quantify Topo I-DNA complexes via glass fiber filter binding. All experiments were performed at least 7 times in duplicate. Results: Potentiation of radiation lethality was seen in the U1-Mel and D54 cell lines. The synergistic effects were (1) dependent on drug concentration, with lethality enhancement and minimal drug lethality alone in the 2-10 μM range (2) dependent on timing, with synergy present only when the drug was present at the time of, or shortly after irradiation, and (3) irreversible, with inhibition of potential lethal damage repair (PLDR). The dose enhancement ratios (DER) for 4 μM Topotecan in the U1-Mel cells was 1.7 - 2.4, depending on the survival endpoints that were used. The DER for 2 μM Topotecan in D54 cells was 3.0 - 4.0. The U1-Mel cells that were exposed to Topotecan

Strong lethality and teratogenicity of strobilurins on Xenopus tropicalis embryos: Basing on ten agricultural fungicides

International Nuclear Information System (INIS)

Li, Dan; Liu, Mengyun; Yang, Yongsheng; Shi, Huahong; Zhou, Junliang; He, Defu

2016-01-01

Agricultural chemical inputs have been considered as a risk factor for the global declines in amphibian populations, yet the application of agricultural fungicides has increased dramatically in recent years. Currently little is known about the potential toxicity of fungicides on the embryos of amphibians. We studied the effects of ten commonly used fungicides (four strobilurins, two SDHIs, two triazoles, fludioxonil and folpet) on Xenopus tropicalis embryos. Lethal and teratogenic effects were respectively examined after 48 h exposure. The median lethal concentrations (LC50s) and the median teratogenic concentrations (TC50s) were determined in line with actual exposure concentrations. These fungicides except two triazoles showed obvious lethal effects on embryos; however LC50s of four strobilurins were the lowest and in the range of 6.81–196.59 μg/L. Strobilurins, SDHIs and fludioxonil induced severe malformations in embryos. Among the ten fungicides, the lowest TC50s were observed for four strobilurins in the range of 0.61–84.13 μg/L. The teratogenicity shared similar dose–effect relationship and consistent phenotypes mainly including microcephaly, hypopigmentation, somite segmentation and narrow fins. The findings indicate that the developmental toxicity of currently-used fungicides involved with ecologic risks on amphibians. Especially strobilurins are highly toxic to amphibian embryos at μg/L level, which is close to environmentally relevant concentrations. - Highlights: • Effects of ten agricultural fungicides were tested on Xenopus tropicalis embryos. • Strobilurin fungicides showed strong lethal and teratogenic effects on embryos. • Lowest LC50 and TC50 were observed for strobilurins in ten fungicides. • μg/L level of toxic concentrations for strobilurins was environmentally relevant. • Teratogenicity shared similar dose–effect relationship and main phenotypes. - Strobilurins induced strong lethality and teratogenicity on Xenopus

Phleomycin-induced lethality and DNA degradation in Escherichia coli K12

Energy Technology Data Exchange (ETDEWEB)

Nakayama, H

1975-01-01

The cell lethality and DNA fragmentation caused by phleomycin (PM) were studied in E. coli K12 strains with special reference to the effects of repair or recombination deficiencies and metabolic inhibitors. Unlike excision-defective derivatives of E. coli B, uvrA, uvrB, and uvrC mutants of strain K12 showed no peculiarities compared with wild type in regard to cell survival. Likewise, mutant alleles at uvrD and polA loci had no effect. In contrast, rec mutants were more sensitive to PM-killing than were rec/sup +/ strains. PM-induced strand breakage in DNA was observed in all strains tested including the above-mentioned mutants. There was no significant distinction between the uvr mutants and the wild type strain, indicating that the uvr-endonuclease was not responsible for the strand breaks. Involvement of endonuclease I was also ruled out. At least some of the PM-induced strand breaks were repairable. PM-induced lethality and strand breakage were totally dependent on energy supply. Inhibition of protein synthesis resulted in a partial and parallel suppression of the two effects. Our results suggest that the lethality is due to DNA strand breakage and the repair of such damage is postulated to be controlled by rec genes.

Ultrasonic study of the charge mismatch effect in charge-ordered (Nd{sub 0.75}Na{sub 0.25}){sub x}(Nd{sub 0.5}Ca{sub 0.5}){sub 1-x}MnO{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Jiang Liang; Su Jinrui; Kong Hui; Liu Yi; Zheng Shiyuan; Zhu Changfei [Laboratory of Advanced Functional Materials and Devices, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China)

2006-09-20

The resistivity, magnetization and ultrasonic properties of charge-ordered polycrystalline (Nd{sub 0.75}Na{sub 0.25}){sub x}(Nd{sub 0.5}Ca{sub 0.5}){sub 1-x}MnO{sub 3} have been investigated from 50 to 300 K. A considerable velocity softening accompanied by an attenuation peak was observed around the charge-ordering transition temperature (T{sub CO}) upon cooling. The simultaneous occurrence of the charge ordering (CO) and the ultrasonic anomaly implies strong electron-phonon coupling, which originates from the cooperative Jahn-Teller effect. At very low temperature, another broad attenuation peak was observed, which is attributed to the phase separation (PS) and gives a direct evidence of spin-phonon coupling in the compound. With increasing x, T{sub CO} shifts to lower temperature, the magnetization of the system is strengthened and the PS is enhanced. The temperature dependence of the longitudinal modulus shows that the Jahn-Teller coupling energy E{sub JT} decreases with increasing Na content. The analysis suggests that the charge mismatch effect may be the main reason for the suppression of the CO and enhancement of the PS.

Non-isothermal synergetic catalytic effect of TiF{sub 3} and Nb{sub 2}O{sub 5} on dehydrogenation high-energy ball milled MgH{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Zhang, Tiebang, E-mail: tiebangzhang@nwpu.edu.cn; Hou, Xiaojiang; Hu, Rui; Kou, Hongchao; Li, Jinshan

2016-11-01

MgH{sub 2}-M (M = TiF{sub 3} or Nb{sub 2}O{sub 5} or both of them) composites prepared by high-energy ball milling are used in this work to illustrate the dehydrogenation behavior of MgH{sub 2} with the addition of catalysts. The phase compositions, microstructures, particle morphologies and distributions of MgH{sub 2} with catalysts have been evaluated. The non-isothermal synergetic catalytic-dehydrogenation effect of TiF{sub 3} and Nb{sub 2}O{sub 5} evaluated by differential scanning calorimetry gives the evidences that the addition of catalysts is an effective strategy to destabilize MgH{sub 2} and reduce hydrogen desorption temperatures and activation energies. Depending on additives, the desorption peak temperatures of catalyzed MgH{sub 2} reduce from 417 °C to 341 °C for TiF{sub 3} and from 417 °C to 336 °C for Nb{sub 2}O{sub 5}, respectively. The desorption peak temperature reaches as low as 310 °C for MgH{sub 2} catalyzed by TiF{sub 3} coupling with Nb{sub 2}O{sub 5}. The non-isothermal synergetic catalytic effect of TiF{sub 3} and Nb{sub 2}O{sub 5} is mainly attributed to electronic exchange reactions with hydrogen molecules, which improve the recombination of hydrogen atoms during dehydrogenation process of MgH{sub 2}. - Highlights: • Catalytic surface for MgH{sub 2} is achieved by high-energy ball milling. • Non-isothermal dehydrogenation behavior of MgH{sub 2} with TiF{sub 3} and/or Nb{sub 2}O{sub 5} is illustrated. • Dehydrogenation activation energies of synergetic catalyzed MgH{sub 2} are obtained. • Synergetic catalytic-dehydrogenation mechanism of TiF{sub 3} and Nb{sub 2}O{sub 5} is proposed.

Cardiac-specific catalase overexpression rescues anthrax lethal toxin-induced cardiac contractile dysfunction: role of oxidative stress and autophagy

Directory of Open Access Journals (Sweden)

Kandadi Machender R

2012-11-01

Full Text Available Abstract Background Lethal and edema toxins secreted by Bacillus anthracis during anthrax infection were found to incite serious cardiovascular complications. However, the underlying mechanisms in anthrax lethal toxin-induced cardiac anomalies remain unknown. This study was designed to evaluate the impact of antioxidant enzyme catalase in anthrax lethal toxin-induced cardiomyocyte contractile dysfunction. Methods Wild type (WT and cardiac-specific catalase overexpression mice were challenged with lethal toxin (2 μg/g, intraperotineally (i.p.. Cardiomyocyte contractile and intracellular Ca2+ properties were assessed 18 h later using an IonOptix edge-detection system. Proteasome function was assessed using chymotrypsin-like and caspase-like activities. GFP-LC3 puncta and Western blot analysis were used to evaluate autophagy and protein ubiquitination. Results Lethal toxin exposure suppressed cardiomyocyte contractile function (suppressed peak shortening, maximal velocity of shortening/re-lengthening, prolonged duration of shortening/re-lengthening, and impaired intracellular Ca2+ handling, the effects of which were alleviated by catalase. In addition, lethal toxin triggered autophagy, mitochondrial and ubiquitin-proteasome defects, the effects of which were mitigated by catalase. Pretreatment of cardiomyocytes from catalase mice with the autophagy inducer rapamycin significantly attenuated or ablated catalase-offered protection against lethal toxin-induced cardiomyocyte dysfunction. On the other hand, the autophagy inhibitor 3-MA ablated or significantly attenuated lethal toxin-induced cardiomyocyte contractile anomalies. Conclusions Our results suggest that catalase is protective against anthrax lethal toxin-induced cardiomyocyte contractile and intracellular Ca2+ anomalies, possibly through regulation of autophagy and mitochondrial function.

Assessing sub-Saharan Erythrina for efficacy: traditional uses, biological activities and phytochemistry.

Science.gov (United States)

Kone, Witabouna Mamidou; Solange, Kakou-Ngazoa E; Dosso, Mireille

2011-05-15

The genus Erythrina comprises more than 100 species, widely distributed in tropical and subtropical areas. In Africa, 31 wild species and 14 cultivated species have been described. In sub-Saharan Africa, Erythrina species are used to treat frequent parasitic and microbial diseases, inflammation, cancer, wounds. The rationale of these traditional uses in African traditional medicine was established by screening several species for biological activities. Promising activities were found against bacteria, parasites (Plasmodium), human and phytopathogenic fungi, some of which were multidrug resistant (MDR) micro organisms. Some species also exhibited antioxidant, anti-inflammatory activities and enzymes inhibitory properties. Most of the species chemically investigated were reported to contain flavanones, prenylated isoflavones, isoflavanones and pterocarpans. Some phytochemicals (vogelin B, vogelin C, isowightcone, abyssinin II, derrone) were the active principles as antibacterials, antifungals, antiplasmodials and inhibitors of enzyme borne diseases (PTP1B, HIV protease, DGAT). This review highlights the important role of Erythrina species as sources of lead compounds or new class of phytotherapeutic agents for fighting against major public health (MDR infections, cancer, diabetes, obesity) in sub-Saharan Africa.

Development of tools for integrated monitoring and assessment of hazardous substances and their biological effects in the Baltic Sea.

Science.gov (United States)

Lehtonen, Kari K; Sundelin, Brita; Lang, Thomas; Strand, Jakob

2014-02-01

The need to develop biological effects monitoring to facilitate a reliable assessment of hazardous substances has been emphasized in the Baltic Sea Action Plan of the Helsinki Commission. An integrated chemical-biological approach is vitally important for the understanding and proper assessment of anthropogenic pressures and their effects on the Baltic Sea. Such an approach is also necessary for prudent management aiming at safeguarding the sustainable use of ecosystem goods and Services. The BEAST project (Biological Effects of Anthropogenic Chemical Stress: Tools for the Assessment of Ecosystem Health) set out to address this topic within the BONUS Programme. BEAST generated a large amount of quality-assured data on several biological effects parameters (biomarkers) in various marine species in different sub-regions of the Baltic Sea. New indicators (biological response measurement methods) and management tools (integrated indices) with regard to the integrated monitoring approach were suggested.

A structural transformation and its effect on the physical properties of the V-substituted Bi sub 2 Sr sub 2 Ca sub 2 Cu sub 3 O sub 1 sub 0 sub + sub y system

CERN Document Server

Yakinci, M E

1997-01-01

Systematic substitution of V in the Bi sub 2 sub - subdelta V subdelta Sr sub 2 Ca sub 2 Cu sub 3 O sub 1 sub 0 sub + sub y system (delta=0, 0.2, 0.4, 0.6, 0.8 and 1) was carried out in order to determine the effect of V ions on the phase formation and on the physical properties of the BSCCO 2223 system. The most interesting observation was structural transformation of the system from tetragonal to orthorhombic after delta=0.6. A solid solubility limit for V was also found to exist. Resistivity and susceptibility studies have shown that high-T sub c superconductivity exists up to delta=0.6 and that the semiconducting-to-metallic transition or fully semiconducting behaviour occurs after this limit. A fractionally small but very-high-T sub c transition at around 210 K was also observed, but it was not reproducible. Among the V-substituted samples the best electrical properties were obtained for delta=0.2; T sub c and T sub o were found to be 112 K and 92 K, respectively, the calculated value of J sub c was foun...

Preparation, properties and anticancer effects of mixed As{sub 4}S{sub 4}/ZnS nanoparticles capped by Poloxamer 407

Energy Technology Data Exchange (ETDEWEB)

Bujňáková, Z., E-mail: bujnakova@saske.sk [Institute of Geotechnics, Slovak Academy of Sciences, Watsonova 45, 04001 Košice (Slovakia); Baláž, M. [Institute of Geotechnics, Slovak Academy of Sciences, Watsonova 45, 04001 Košice (Slovakia); Zdurienčíková, M.; Sedlák, J. [Cancer Research Institute, BMC Slovak Academy of Sciences, Dúbravská 9, 84505 Bratislava (Slovakia); Čaplovičová, M. [STU Centre for Nanodiagnostics, Slovak University of Technology, Vazovova 5, 81243 Bratislava (Slovakia); Čaplovič, Ľ. [Faculty of Materials Science and Technology, Slovak University of Technology, Paulínska 16, 91724 Trnava (Slovakia); Dutková, E.; Zorkovská, A.; Turianicová, E.; Baláž, P. [Institute of Geotechnics, Slovak Academy of Sciences, Watsonova 45, 04001 Košice (Slovakia); Shpotyuk, O. [Scientific Research Company “Carat”, Stryjska 202, 79031 Lviv (Ukraine); Institute of Physics, Jan Dlugosz University, Armii Krajowej 13/15., 42200 Czestochowa (Poland); and others

2017-02-01

Arsenic sulfide compounds have a long history of application in a traditional medicine. In recent years, realgar has been studied as a promising drug in cancer treatment. In this study, the arsenic sulfide (As{sub 4}S{sub 4}) nanoparticles combined with zinc sulfide (ZnS) ones in different molar ratio have been prepared by a simple mechanochemical route in a planetary mill. The successful synthesis and structural properties were confirmed and followed via X-ray diffraction and high-resolution transmission electron microscopy measurements. The morphology of the particles was studied via scanning electron microscopy and transmission electron microscopy methods and the presence of nanocrystallites was verified. For biological tests, the prepared As{sub 4}S{sub 4}/ZnS nanoparticles were further milled in a circulation mill in a water solution of Poloxamer 407 (0.5 wt%), in order to cover the particles with this biocompatible copolymer and to obtain stable nanosuspensions with unimodal distribution. The average size of the particles in the nanosuspensions (~ 120 nm) was determined by photon cross-correlation spectroscopy method. Stability of the nanosuspensions was determined via particle size distribution and zeta potential measurements, confirming no physico-chemical changes for several months. Interestingly, with the increasing amount of ZnS in the sample, the stability was improved. The anti-cancer effects were tested on two melanoma cell lines, A375 and Bowes, with promising results, confirming increased efficiency of the samples containing both As{sub 4}S{sub 4} and ZnS nanocrystals. - Highlights: • Mixed As{sub 4}S{sub 4}/ZnS nanoparticles were prepared by dry milling in the first stage • Stable nanosuspensions of As{sub 4}S{sub 4}/ZnS nanoparticles capped by Poloxamer 407 were prepared by wet milling in the second stage • ZnS in the samples is beneficial: higher values of S{sub A}, stability, solubility and anticancer activity were improved.

Effects of UV, sunlight and X-ray radiation on quiescent human cells in culture

International Nuclear Information System (INIS)

Kantor, G.J.

1986-01-01

Nondividing human diploid fibroblasts (HDF) in culture have been used to study the effect on cell lethality of ultraviolet light, natural sunlight and X-rays. A lethal effect is defined as cellular degeneration, loss from the culture and inability to exclude vital strains. Far- and mid-UV have a readily observable lethal effect (cell loss), with DNA and DNA damage as the critical target and critical damage respectively. In part, natural sunlight kills cells by a similar mechanism but has an additional lethal effect at longer exposure times. This additional effect is expressed by the retention of the dead cells in culture, in contrast to the UV-induced promotion of cell degeneration and loss. Relatively large doses of X-rays that destroy proliferative capacity, have no detectable lethal effect on the maintenance of non-dividing cells. The biological response of nondividing HDF to radiations from different parts of the electromagnetic spectrum is dissimilar. (author)

Frequencies of aneuploidy and dominant lethal mutations in young female mice induced by low dose γ-rays

International Nuclear Information System (INIS)

Yao Suyan; Zhang Chaoyang; Dai Lianlian; Gao Changwen

1991-01-01

Relationship between aneuploidy, dominant lethal mutations and doses in young feral mice induced by low dose γ-rays was examined. The results suggest that the frequencies of aneuploidy of embryos increased at 0.15 Gy, but increases at over 0.50 Gy after irradiation in groups. The frequencies of aneuploidy and dominant lethal mutations increased with increasing doses and fitted linear relationship. This dose-response relationship of trisomic was not significant. The frequency of dominant lethal mutations induced by 60 Co γ irradiation is 5.59%. The effect of dominant lethal mutation is higher than that of the aneuploidy

Biological reduction-deposition and luminescent properties of nanostructured CePO{sub 4}@NaCe(SO{sub 4}){sub 2}(H{sub 2}O) and CePO{sub 4}

Energy Technology Data Exchange (ETDEWEB)

Yu, Xiaoniu [School of Materials Science and Engineering, Southeast University, Nanjing 211189 (China); Research Institute of Green Construction Materials, Southeast University, Nanjing 211189 (China); Qian, Chunxiang, E-mail: cxqian@seu.edu.cn [School of Materials Science and Engineering, Southeast University, Nanjing 211189 (China); Research Institute of Green Construction Materials, Southeast University, Nanjing 211189 (China)

2016-03-01

Nano-sized CePO{sub 4}@NaCe(SO{sub 4}){sub 2}(H{sub 2}O) and CePO{sub 4} with hexagonal phase have been prepared by simply varying the reactant P/Ce molar ratio in bacterial liquid. The phase composition of two samples was checked via Fourier transform infrared spectroscopy (FTIR), energy dispersive analysis of X-rays (EDS) and X-ray diffraction (XRD) analyses, displaying the presence of CePO{sub 4}@NaCe(SO{sub 4}){sub 2}(H{sub 2}O) and CePO{sub 4} with average crystallite size are 32.34 and 15.61 nm, respectively. The scanning electron microscopy (SEM) images show that nano-clusters and sphere-like in shape with a narrow diameter distribution were observed in two samples. The transmission electron microscopy (TEM) photographs further indicate obtained CePO{sub 4}@NaCe(SO{sub 4}){sub 2}(H{sub 2}O) and CePO{sub 4} nanoparticles correspond to nanosheets and nanorods, respectively. The emission spectra of CePO{sub 4}@NaCe(SO{sub 4}){sub 2}(H{sub 2}O) and CePO{sub 4} display a broad band of 300–380 nm range with the strongest emission at 342 nm in the violet region. - Highlights: • A new method was found to synthesize CePO{sub 4}@NaCe(SO{sub 4}){sub 2}(H{sub 2}O) and CePO{sub 4} nanoparticles. • CePO{sub 4}@NaCe(SO{sub 4}){sub 2}(H{sub 2}O) nanoparticles have good luminescent properties. • Size and luminescent properties of two samples have been studied and compared.

Constraining the role of iron in environmental nitrogen transformations. Dual stable isotope systematics of abiotic NO<sub>2sub>- reduction by Fe(II) and its production of N<sub>2sub>O

Energy Technology Data Exchange (ETDEWEB)

Johnston, David [Harvard Univ., Cambridge, MA (United States); Wankel, Scott David [Woods Hole Oceanographic Inst., MA (United States); Buchwald, Carolyn [Woods Hole Oceanographic Inst., MA (United States); Hansel, Colleen [Woods Hole Oceanographic Inst., MA (United States)

2015-09-16

Redox reactions involving nitrogen and iron have been shown to have important implications for mobilization of priority contaminants. Thus, an understanding of the linkages between their biogeochemical cycling is critical for predicting subsurface mobilization of radionuclides such as uranium. Despite mounting evidence for biogeochemical interactions between iron and nitrogen, our understanding of their environmental importance remains limited. Here we present an investigation of abiotic nitrite (NO<sub>2sub>^-) reduction by Fe(II) or ‘chemodenitrification,’ and its relevance to the production of nitrous oxide (N<sub>2sub>O), specifically focusing on dual (N and O) isotope systematics under a variety of environmentally relevant conditions. We observe a range of kinetic isotope effects that are regulated by reaction rates, with faster rates at higher pH (~8), higher concentrations of Fe(II) and in the presence of mineral surfaces. A clear non-linear relationship between rate constant and kinetic isotope effects of NO<sub>2sub>^- reduction was evident (with larger isotope effects at slower rates) and is interpreted as reflecting the dynamics of Fe(II)-N reaction intermediates. N and O isotopic composition of product N<sub>2sub>O also suggests a complex network of parallel and/or competing pathways. Our findings suggest that NO<sub>2sub>^- reduction by Fe(II) may represent an important abiotic source of environmental N<sub>2sub>O, especially in iron-rich environments experiencing dynamic redox variations. This study provides a multi-compound, multi-isotope framework for evaluating the environmental occurrence of abiotic NO<sub>2sub>^- reduction and N<sub>2sub>O formation, helping future studies constrain the relative roles of abiotic and biological N<sub>2sub>O production pathways.

Synthetic lethality between gene defects affecting a single non-essential molecular pathway with reversible steps.

Directory of Open Access Journals (Sweden)

Andrei Zinovyev

2013-04-01

Full Text Available Systematic analysis of synthetic lethality (SL constitutes a critical tool for systems biology to decipher molecular pathways. The most accepted mechanistic explanation of SL is that the two genes function in parallel, mutually compensatory pathways, known as between-pathway SL. However, recent genome-wide analyses in yeast identified a significant number of within-pathway negative genetic interactions. The molecular mechanisms leading to within-pathway SL are not fully understood. Here, we propose a novel mechanism leading to within-pathway SL involving two genes functioning in a single non-essential pathway. This type of SL termed within-reversible-pathway SL involves reversible pathway steps, catalyzed by different enzymes in the forward and backward directions, and kinetic trapping of a potentially toxic intermediate. Experimental data with recombinational DNA repair genes validate the concept. Mathematical modeling recapitulates the possibility of kinetic trapping and revealed the potential contributions of synthetic, dosage-lethal interactions in such a genetic system as well as the possibility of within-pathway positive masking interactions. Analysis of yeast gene interaction and pathway data suggests broad applicability of this novel concept. These observations extend the canonical interpretation of synthetic-lethal or synthetic-sick interactions with direct implications to reconstruct molecular pathways and improve therapeutic approaches to diseases such as cancer.

Breakthrough of ultraviolet light from various brands of fluorescent lamps: Lethal effects on DNA repair-defective bacteria

International Nuclear Information System (INIS)

Hartman, P.E.; Biggley, W.H.

1996-01-01

In a comparative study of 17 pairs of 15 W fluorescent lamps intended for use in homes and purchased in local stores, we detect over 10-fold differences in UVB + UVC emissions between various lamps. This breakthrough of ultraviolet (UV) light is in part correlated with ability of lamps to kill DNA repair-defective recA - uvrB - Salmonella. Relative proficiency of lamps in eliciting photoreactivation of UV-induced DNA lesions also plays a prominent role in the relative rates of bacterial inactivation by emissions from different lamps. Lamps made in Chile, such as Phillips brand lamps and one type of General Electric lamp, produce far less UVB + UVC and fail to kill recA - uvrB - bacteria. In contrast, all tested lamps manufactured in the USA, Hungary, and Japan exhibit readily observed deleterious biological effects. When an E. coli recA - uvrB - phr - (photolyase-negative) triple mutant is used for assay, lethal radiations are detected from all lamps, and single-hit exponential inactivation rates rather closely correlate to amount of directly measured UVB + UVC output of each pair of lamps. Although all lamps tested may meet international and Unite States standards for radiation safely, optimal practices in lamp manufacture are clearly capable of decreasing human exposure to indoor UV light. 38 refs., 3 figs., 1 tab

Context-dependent interactive effects of non-lethal predation on larvae impact adult longevity and body composition.

Science.gov (United States)

Chandrasegaran, Karthikeyan; Kandregula, Samyuktha Rao; Quader, Suhel; Juliano, Steven A

2018-01-01

Predation impacts development, behavior and morphology of prey species thereby shaping their abundances, distribution and community structure. Non-lethal threat of predation, specifically, can have a strong influence on prey lifehistory characteristics. While investigations often focus on the impact of predation threat on prey in isolation, tests of its interactive effects with food availability and resource competition on prey survival and fitness can improve understanding of costs, benefits and trade-offs of anti-predator strategies. This study, involving Aedes aegypti mosquitoes as a model organism, investigates both simple and interactive effects of predation threat during the larval stage on survival, size at and time to maturity, stored teneral reserves of glycogen, protein and lipid in adults, and adult longevity. Our results show that development times of mosquito larvae were increased (by 14.84% in males and by 97.63% in females), and size of eclosing adults decreased (by 62.30% in males and by 58.33% in females) when exposed to lowered nutrition and elevated intraspecific competition, but that predation had no detectable effect on these simple traits. Teneral reserves of glycogen, protein and lipid and adult longevity were positively correlated with adult body size. Non-lethal predation threat had significant interactive effects with nutrition and larval competition on teneral reserves in males and adult longevity in males and females. The sexes responded differently to conditions encountered as larvae, with the larval environment affecting development and adult characteristics more acutely for females than for males. The outcome of this study shows how threat of predation on juveniles can have long-lasting effects on adults that are likely to impact mosquito population dynamics and that may impact disease transmission.

Mechanism of superconductivity in Yb sub 1 sub - sub x Ca sub x (Ba sub 0 sub . sub 8 Sr sub O sub . sub 2) sub 2 Cu sub 3 O sub 6 sub + subdelta

CERN Document Server

Anvekar, T S; Sarode, P R; Kamat-Dalal, V N; Narlikar, Anant V

2002-01-01

EXAFS, X-ray Rietveld refinement and infra-red absorption measurements have been made on Yb sub 1 sub - sub x Ca sub x (Ba sub 0 sub . sub 8 Sr sub 0 sub . sub 2) sub 2 Cu sub 3 O sub 6 sub + subdelta in order to understand the effect of Ca doping on the local structure of planar Cu ion. The study indicates that restoration of superconductivity is due to oxidation of copper ions in the CuO sub 2 planes. (author)

Lethality of Rendang packaged in multilayer retortable pouch with sterilization process

Science.gov (United States)

Praharasti, A. S.; Kusumaningrum, A.; Frediansyah, A.; Nurhikmat, A.; Khasanah, Y.; Suprapedi

2017-01-01

Retort Pouch had become a choice to preserve foods nowadays, besides the used of the can. Both had their own advantages, and Retort Pouch became more popular for the reason of cheaper and easier to recycle. General Method usually used to estimate the lethality of commercial heat sterilization process. Lethality value wa s used for evaluating the efficacy of the thermal process. This study aimed to find whether different layers of pouch materials affect the lethality value and to find differences lethality in two types of multilayer retort pouch, PET/Aluminum Foil/Nylon/RCPP and PET/Nylon/Modified Aluminum/CPP. The result showed that the different layer arrangement was resulted different Sterilization Value (SV). PET/Nylon/Modified Aluminum/CPP had better heat penetration, implied by the higher value of lethality. PET/Nylon/Modified Aluminum/CPP had the lethality value of 6,24 minutes, whereas the lethality value of PET/Aluminum Foil/Nylon/RCPP was 3,54 minutes.

Are Trp53 rescue of Brca1 embryonic lethality and Trp53/Brca1 breast cancer association related?

International Nuclear Information System (INIS)

McAllister, Kimberly A; Wiseman, Roger W

2002-01-01

Brca1 is involved in multiple biological pathways including DNA damage repair, transcriptional regulation, and cell-cycle progression. A complex pattern of interactions of Brca1 with Trp53 has also emerged. Xu and coworkers found that haploid loss of Trp53 significantly reduces the embryonic lethality observed in mice with a homozygous in-frame deletion of Brca1 exon 11. They report that widespread apoptosis correlates with the embryonic lethality resulting from this homozygous Δ11 Brca1 mutation. A mechanism responsible for Brca1-associated carcinogenesis is proposed. These experiments extend our knowledge of a complex Brca1/Trp53 relationship. However, the precise mechanisms through which Brca1 interacts with Trp53 to suppress mammary tumor formation have yet to be elucidated

Adverse effects induced by ecgonine methyl ester to the zebra mussel: A comparison with the benzoylecgonine

International Nuclear Information System (INIS)

Parolini, Marco; Binelli, Andrea

2013-01-01

Cocaine and its metabolites are the prevalent psychotropic substances in aquatic environment. However, to date the knowledge on their adverse effects to non-target organisms is inadequate. The aims of this study were to investigate sub-lethal effects induced by the ecgonine methyl ester (EME) to the freshwater bivalve Dreissena polymorpha and to compare its toxicity to that by benzoylecgonine (BE), the other main cocaine metabolite. EME sub-lethal effects were investigated by 14 days in-vivo exposures and a multi-biomarker approach. Slight variations in biomarker responses were found at 0.15 μg/L treatment. 0.5 μg/L EME treatment induced destabilization of lysosome membranes, an overall inactivation of defense enzymes, increases in lipid peroxidation, protein carbonylation and DNA fragmentation, but no variations in fixed genetic damage. The use of a biomarker response index (BRI) showed that at 0.5 μg/L both cocaine metabolites had the same toxicity to zebra mussels specimens. -- Highlights: •Sub-lethal effects induced by ecgonine methyl ester (EME) to D. polymorpha were investigated. •Realistic EME concentrations caused notable adverse effects in treated bivalves. •EME induced oxidative injuries to treated-mussel lipids, protein and DNA. •EME toxicity was comparable to the benzoylecgonine one. -- Environmentally relevant ecgonine methyl ester concentrations induced adverse effects to zebra mussels

Dark-red-emitting CdTe{sub 0.5}Se{sub 0.5}/Cd{sub 0.5}Zn{sub 0.5}S quantum dots: Effect of chemicals on properties

Energy Technology Data Exchange (ETDEWEB)

Yang, Ping, E-mail: mse_yangp@ujn.edu.cn; Zhang, Aiyu; Li, Xiaoyu; Liu, Ning; Zhang, Yulan; Zhang, Ruili

2013-08-15

CdTe{sub 0.5}Se{sub 0.5}/Cd{sub 0.5}Zn{sub 0.5}S core/shell quantum dots (QDs) with a tunable photoluminescence (PL) range from yellow to dark red (up to a PL peak wavelength of 683 nm) were fabricated using various reaction systems. The core/shell QDs created in the reaction solution of trioctylamine (TOA) and oleic acid (OA) at 300 °C exhibited narrow PL spectra and a related low PL efficiency (38%). In contrast, the core/shell QDs prepared in the solution of 1-octadecene (ODE) and hexadecylamine (HDA) at 200 °C revealed a high PL efficiency (70%) and broad PL spectra. This phenomenon is ascribed that the precursor of Cd, reaction temperature, solvents, and ligands affected the formation process of the shell. The slow growth rate of the shell in the solution of ODE and HDA made QDs with a high PL efficiency. Metal acetate salts without reaction with HDA led to the core/shell QDs with a broad size distribution. - Graphical abstract: CdTe{sub 0.5}Se{sub 0.5}/Cd{sub 0.5}Zn{sub 0.5}S quantum dots (QDs) with tunable photoluminescence, high PL efficiency, and high stability through organic synthesis, in which chemicals affected the properties of the QDs. Display Omitted - Highlights: • CdTe{sub 0.5}Se{sub 0.5}/Cd{sub 0.5}Zn{sub 0.5}S quantum dots created via organic synthesis. • Chemicals affected the properties of the quantum dots. • The quantum dots revealed high photoluminescence efficiency and stability. • The quantum dots with tunable photoluminescence in a range from yellow to dark red. • The QDs are utilizable for various applications such as biological labeling.

Alteration in DNA structure, molecular responses and Na+ -K+ -ATPase activities in the gill of Nile tilapia, Oreochromis niloticus (Linnaeus, 1758) in response to sub-lethal verapamil.

Science.gov (United States)

Ajima, Malachy N O; Pandey, Pramod K; Kumar, Kundan; Poojary, Nalini

2018-01-01

The ecotoxicological consequences of residues from pharmaceutical drugs on aquatic biota have necessitated the development of sensitive and reliable techniques to assess the impact of these xenobiotics on aquatic organisms. This study investigated the alteration in DNA structure, molecular responses and the activities of Na + -K + -ATPase and antioxidant enzymes in the gill of Nile tilapia, Oreochromis niloticus, exposed to long-term effects at the concentrations (0.14, 0.28 and 0.57mgL -1 ) of verapamil in static renewal system for 15, 30, 45 and 60 days. Evaluation of DNA structure, using single cell gel electrophoresis, revealed certain degree of DNA damages in the gill in a time and concentration-dependent relationship. Transcription of mRNA of superoxide dismutase (sod), catalase (cat) and heat shock protein (hsp70) genes in the gill of the fish showed the genes were up-regulated. Na + -K + -ATPase activity was inhibited in a concentration and time dependent manner. The indices of oxidative stress biomarkers (lipid peroxidation and carbonyl protein) as well as superoxide dismutase, glutathione peroxidase, glutathione-S-transferase were elevated in the treated fish in comparison to the control. Further, the level of reduced glutathione and catalase activity were inhibited at 0.28mgL -1 after day 30. Long-term exposure to sub-lethal concentration of verapamil can cause DNA damages, molecular effects and oxidative stress in O. niloticus. The biomarkers analysed can be used as early warning signals in environmental biomonitoring and assessment of drug contamination in aquatic ecosystem. Copyright © 2017 Elsevier Inc. All rights reserved.

Effect of two viscosity models on lethality estimation in sterilization of liquid canned foods.

Science.gov (United States)

Calderón-Alvarado, M P; Alvarado-Orozco, J M; Herrera-Hernández, E C; Martínez-González, G M; Miranda-López, R; Jiménez-Islas, H

2016-09-01

A numerical study on 2D natural convection in cylindrical cavities during the sterilization of liquid foods was performed. The mathematical model was established on momentum and energy balances and predicts both the heating dynamics of the slowest heating zone (SHZ) and the lethal rate achieved in homogeneous liquid canned foods. Two sophistication levels were proposed in viscosity modelling: 1) considering average viscosity and 2) using an Arrhenius-type model to include the effect of temperature on viscosity. The remaining thermodynamic properties were kept constant. The governing equations were spatially discretized via orthogonal collocation (OC) with mesh size of 25 × 25. Computational simulations were performed using proximate and thermodynamic data for carrot-orange soup, broccoli-cheddar soup, tomato puree, and cream-style corn. Flow patterns, isothermals, heating dynamics of the SHZ, and the sterilization rate achieved for the cases studied were compared for both viscosity models. The dynamics of coldest point and the lethal rate F0 in all food fluids studied were approximately equal in both cases, although the second sophistication level is closer to physical behavior. The model accuracy was compared favorably with reported sterilization time for cream-style corn packed at 303 × 406 can size, predicting 66 min versus an experimental time of 68 min at retort temperature of 121.1 ℃. © The Author(s) 2016.

Effect of a non lethal whole-body gamma irradiation on the spontaneous and evoked electroencephalographic activities of the adult rabbit

International Nuclear Information System (INIS)

Court, L.

1969-01-01

The whole of the experimental methods described (animal preparation, achievement of a precise physiological technique, dosimetry, biological information processing) allowed us to follow the changes for 15 days in the spontaneous and evoked electroencephalogram activities of rabbits submitted to a non-lethal 400 rads whole-body gamma-irradiation. Behavioural troubles, changes in the arousal state and the spontaneous electrical activity of the neo-cortex and hippocampus were noticed constantly together with an enhanced cortical excitability, and the appearance of elements of the paroxystic series sometimes in contrast with a general decrease in amplitude. After a visual stimulus the general morphology of evoked activities at the level of the primary visual areas and hippocampus was unchanged, but enhanced latencies and delays, less systematic modifications in amplitudes seemed to show out a direct effect of radiations on the nervous system and sensorial activities; these troubles seemed to occur independently from the basic electrical activity. As a whole, the changes observed were usually transitory and varied with each individual. Finally an assumption is made to explain the mechanism of arousal troubles and the general evolution of spontaneous electrical activity in the brain. (author) [fr

The population genetics of X-autosome synthetic lethals and steriles.

Science.gov (United States)

Lachance, Joseph; Johnson, Norman A; True, John R

2011-11-01

Epistatic interactions are widespread, and many of these interactions involve combinations of alleles at different loci that are deleterious when present in the same individual. The average genetic environment of sex-linked genes differs from that of autosomal genes, suggesting that the population genetics of interacting X-linked and autosomal alleles may be complex. Using both analytical theory and computer simulations, we analyzed the evolutionary trajectories and mutation-selection balance conditions for X-autosome synthetic lethals and steriles. Allele frequencies follow a set of fundamental trajectories, and incompatible alleles are able to segregate at much higher frequencies than single-locus expectations. Equilibria exist, and they can involve fixation of either autosomal or X-linked alleles. The exact equilibrium depends on whether synthetic alleles are dominant or recessive and whether fitness effects are seen in males, females, or both sexes. When single-locus fitness effects and synthetic incompatibilities are both present, population dynamics depend on the dominance of alleles and historical contingency (i.e., whether X-linked or autosomal mutations occur first). Recessive synthetic lethality can result in high-frequency X-linked alleles, and dominant synthetic lethality can result in high-frequency autosomal alleles. Many X-autosome incompatibilities in natural populations may be cryptic, appearing to be single-locus effects because one locus is fixed. We also discuss the implications of these findings with respect to standing genetic variation and the origins of Haldane's rule.

Effect of H{sub 2}O{sub 2} on the corrosion behavior of 304L stainless steel

Energy Technology Data Exchange (ETDEWEB)

Song, Taek Hoh; Kim, In Sub [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Noh, Sung Kee [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1995-08-01

In connection with the safe storage of high level nuclear waste, effect of H{sub 2}O{sub 2} on the corrosion behavior of 304L stainless steel was examined. Open circuit potentials and polarization curves were measured with and without H{sub 2}O{sub 2}. The experimental results show that H{sub 2}O{sub 2} increased corrosion potential and decreased pitting potential. The passive range, therefore, decreased as H{sub 2}O{sub 2} concentration increased, indicating that pitting resistance was decreased by the existence of H{sub 2}O{sub 2} in the electrolyte. These effects of H{sub 2}O{sub 2} on corrosion of 304L stainless steel are considered to be similar to those of {gamma}-irradiation. To compare the effects of H{sub 2}O{sub 2} with those of O{sub 2}, cathodic and anodic polarization curves were made in three types of electrolyte such as aerated, deaerated, and stirred electrolyte. The experimental results show that the effects of H{sub 2}O{sub 2} on the corrosion behavior were very similar to those of O{sub 2} such as increase of corrosion potential, decrease of pitting resistance, and increase of repassivation potential. In acid and alkaline media, the corrosion potential shifts by H{sub 2}O{sub 2} were restricted by the large current density of proton reduction and by the le Chatelier`s principle respectively. 13 figs., 1 tabs., 17 refs. (Author).

Interaction of radiation, Dihydroxyanthraquinone, and Adriamycin on the induction of acute lethality in mice

International Nuclear Information System (INIS)

Kimler, B.F.; Cox, G.G.; Reddy, E.K.

1984-01-01

The acute lethality induced by combinations of radiation, Dihydroxyanthraquinone (DHAQ), and Adriamycin (ADR) was investigated in mice. Whole-body irradiation produced acute lethality, with an LD-50/30 of approximately 6.5 Gy. ADR and DHAQ produced LD-50/30's of 14 and 4 mg/kg, respectively. When 10 mg/kg doses were fractionated into 5 x 2 mg/kg daily doses, both drugs were equally or more efficient at producing mortality, 90% by day 30. When 4 Gy radiation was combined with 5 mg/kg ADR or 5 mg/kg DHAQ, a response no greater than that produced by drug alone was obtained. However, when 5 mg/kg ADR was administered concomitantly with 5 mg/kg DHAQ, there was a less-than-additive induction of lethality, resulting in only 21% mortality by day 20. ADR and DHAQ (at doses of 5 mg/kg) were combined but with a 1 day interval between drugs, the protective effect was lost and animals died earlier than after either agent alone. At present, no definite explanation is available for this unusual protective effect of ADR against acute lethality induced by DHAQ

Toxicology Studies on Lewisite and Sulfur Mustard Agents: Modified Dominant Lethal Study of Sulfur Mustard in Rats Final Report

Energy Technology Data Exchange (ETDEWEB)

Sasser, L. B.; Cushing, J. A.; Kalkwarf, D. R.; Buschbom, R. L.

1989-05-01

Occupational health standards have not been established for sulfur mustard (HD) [bis{2-chloroethyl)-sulfide) ' a strong alkylating agent with known mutagenic properties. Little, however, is known about the mutagenic activity of HD in mammalian species and data regarding the dominant lethal effects of HD are ambiguous. The purpose of this study was to determine the dominant lethal effect in male and female rats orally exposed to HD. The study was conducted in two phases; a female dominant lethal phase and a male dominant lethal phase. Sprague-Dawley rats of each sex were administered 0.08, 0.20, or 0.50 mg/kg HD in sesame oil 5 days/week for 10 weeks. For the female phase, treated or untreated males were mated with treated females and their fetuses were evaluated at approximately 14 days after copulation. For the male dominant lethal phase, treated males cohabited with untreated femal (during 5 days of each week for 10 weeks) and females were sacrificed for fetal evaluation 14 days after the midweek of cohabitation during each of the 10 weeks. The appearance and behavior of the rats were unremarkable throughout the experiment and there were no treatment-related deaths. Growth rates were reduced in both female and male rats treated with 0.50 mg/kg HD. Indicators of reproductive performance did not demonstrate significant female dominant lethal effects, although significant male dominant lethal effects were observed at 2 and 3 week post-exposure. These effects included increases of early fetal resorptions and preimplantation losses and decreases of total live embryo implants. These effects were most consistently observed at a dose of 0.50 mg/kg, but frequently occurred at the lower doses. Although no treatment-related effects on male reproductive organ weights or sperm motility were found, a significant increase in the percentage of abnormal sperm was detected in males exposed to 0. 50 mg/kg HD. The timing of these effects is consistent with an effect during the

Myxoma virus M130R is a novel virulence factor required for lethal myxomatosis in rabbits.

Science.gov (United States)

Barrett, John W; Werden, Steven J; Wang, Fuan; McKillop, William M; Jimenez, June; Villeneuve, Danielle; McFadden, Grant; Dekaban, Gregory A

2009-09-01

Myxoma virus (MV) is a highly lethal, rabbit-specific poxvirus that induces a disease called myxomatosis in European rabbits. In an effort to understand the function of predicted immunomodulatory genes we have deleted various viral genes from MV and tested the ability of these knockout viruses to induce lethal myxomatosis. MV encodes a unique 15 kD cytoplasmic protein (M130R) that is expressed late (12h post infection) during infection. M130R is a non-essential gene for MV replication in rabbit, monkey or human cell lines. Construction of a targeted gene knockout virus (vMyx130KO) and infection of susceptible rabbits demonstrate that the M130R knockout virus is attenuated and that loss of M130R expression allows the rabbit host immune system to effectively respond to and control the lethal effects of MV. M130R expression is a bona fide poxviral virulence factor necessary for full and lethal development of myxomatosis.

Effect of H{sub 2}O{sub 2} on the corrosion behavior of 304L stainless steel

Energy Technology Data Exchange (ETDEWEB)

Song, Taek Ho

1994-02-15

In connection with the safe storage of high level nuclear waste, effect of H{sub 2}O{sub 2} on the corrosion behavior of 304L stainless steel was examined. Open circuit potentials and polarization curves were measured with and without H{sub 2}O{sub 2}. The experimental results show that H{sub 2}O{sub 2} increased corrosion potential and decreased pitting potential. The passive range, therefore, decreased as H{sub 2}O{sub 2} concentration increased, indicating that pitting resistance was decreased by the existence of H{sub 2}O{sub 2} in the electrolyte. These effects of H{sub 2}O{sub 2} on corrosion of 304L stainless steel are considered to be similar to those of γ-irradiation. To compare the effects of H{sub 2}O{sub 2} with those of O{sub 2}, cathodic and anodic polarization curves were made in three types of electrolyte such as aerated, deaerated, and stirred electrolyte. The experimental results show that the effects of H{sub 2}O{sub 2} on the corrosion behavior were very similar to those of O{sub 2} such as increase of corrosion potential, decrease of pitting resistance, and increase of repassivation potential. Further, H{sub 2}O{sub 2} played much greater role in controlling cathodic reaction rate in neutral water environment. In acid and alkaline media, potential shifts by H{sub 2}O{sub 2} were restricted by the large current density of proton reduction and by the le Chatelier's principle respectively.

[Bladder tumor lethality. Results in the autonomous community of Rioja between 1975-1991].

Science.gov (United States)

Fernández Fernández, A; Gil Fabra, J; Fernández Ruíz, M; Angulo Castellanos, M G; Blanco Martín, E; Otero Mauricio, G

1998-01-01

Between 1975-1991, a total of 557 cases of bladder carcinoma were identified in the Autonomous Community of La Rioja (CAR) which were followed up to December 1994. The overall lethality was 21.9%. 492 cases with 22.35% lethality were identified in males. In females, however, there was 65 cases with 18.46% lethality. The comparison of males and females lethality resulted in p = 0.525. Lethality between cases diagnosed within each 5-year period analyzed is: 1975-1981: 177 cases, lethality 23.72%. 1982-1986: 168 cases, lethality 30.95%. 1987-1991: 212 cases, lethality 13.20%. Between the first and the second 5-year periods, p = 0.132; between the first and third 5-year periods p = 0.007 and between the second and third 5-year periods p CAR for a 22.35% lethality. Lethality is higher in males that in females but the difference is not statistically significant. In the last 5-year period assessed, 1987-1991, a reduction of lethality from bladder neoplasms has been documented.

Structural, spectroscopic and cytotoxicity studies of TbF{sub 3}@CeF{sub 3} and TbF{sub 3}@CeF{sub 3}@SiO{sub 2} nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Grzyb, Tomasz; Runowski, Marcin [Adam Mickiewicz University, Department of Rare Earths, Faculty of Chemistry (Poland); Dabrowska, Krystyna [Polish Academy of Sciences, Bacteriophage Laboratory, Institute of Immunology and Experimental Therapy (Poland); Giersig, Michael; Lis, Stefan, E-mail: blis@amu.edu.pl [Adam Mickiewicz University, Department of Rare Earths, Faculty of Chemistry (Poland)

2013-10-15

Terbium fluoride nanocrystals, covered by a shell, composed of cerium fluoride were synthesized by a co-precipitation method. Their complex structure was formed spontaneously during the synthesis. The surface of these core/shell nanocrystals was additionally modified by silica. The properties of TbF{sub 3}@CeF{sub 3} and TbF{sub 3}@CeF{sub 3}@SiO{sub 2} nanocrystals, formed in this way, were investigated. Spectroscopic studies showed that the differences between these two groups of products resulted from the presence of the SiO{sub 2} shell. X-ray diffraction patterns confirmed the trigonal crystal structure of TbF{sub 3}@CeF{sub 3} nanocrystals. High resolution transmission electron microscopy in connection with energy-dispersive X-ray spectroscopy showed a complex structure of the formed nanocrystals. Crystallized as small discs, 'the products', with an average diameter around 10 nm, showed an increase in the concentration of Tb{sup 3+} ions from surface to the core of nanocrystals. In addition to photo-physical analyses, cytotoxicity studies were performed on HSkMEC (Human Skin Microvascular Endothelial Cells) and B16F0 mouse melanoma cancer cells. The cytotoxicity of the nanomaterials was neutral for the investigated cells with no toxic or antiproliferative effect in the cell cultures, either for normal or for cancer cells. This fact makes the obtained nanocrystals good candidates for biological applications and further modifications of the SiO{sub 2} shell.Graphical Abstract.

Cyclotron resonance and De Haas-Van Alphen effect in (BEDT-TTF) sub 8 Hg sub 4 Cl sub 1 sub 2 (C sub 6 H sub 5 Cl) sub 2 organic conductor

CERN Document Server

Voskobojnikov, I B; Samarin, N A; Cluchanko, N E; Lyubovskaya, R N; Moshchalkov, V V

2002-01-01

Within 0.33-1.44 K temperature range at B <= 50 T magnetic field values one measured the De Haas-Van Alphen effect for (BEDT-TTF) sub 8 Hg sub 4 Cl sub 1 sub 2 (C sub 6 H sub 5 Cl) sub 2 organic quasi-two-dimensional conductor. Analysis of quantum oscillations with regard to data on cyclotron resonance derived for 40-120 GHz frequency interval enabled to determine that a complex spectrum of quantum oscillations was formed by alpha approx 256 T and beta approx 670-610 T fundamental frequencies as well as, by combination and multiple frequencies. It is shown that nature of temperature rearrangement of oscillation spectrum may be interpreted in terms of model taking account of occurrence of magnetic phase transition at T sub c approx 0.9 K and proximity of a fundamental frequency with m* = 1.48m sub 0 efficient mass to the spin dumping condition

Magnetic effects on the dielectric and polarization properties in BiAlO{sub 3}/La{sub 0.67}Sr{sub 0.33}MnO{sub 3} heterostructure

Energy Technology Data Exchange (ETDEWEB)

Zhao, Yanan [Shaanxi Key Laboratory of Condensed Matter Structures and Properties, Northwestern Polytechnical University, Xi' an (China); College of Engineering Management, Shaanxi Radio and Television University, Xi' an (China); Luo, Bingcheng; Chen, Changle; Xing, Hui; Wang, Jianyuan; Jin, Kexin [Shaanxi Key Laboratory of Condensed Matter Structures and Properties, Northwestern Polytechnical University, Xi' an (China)

2017-09-15

BiAlO{sub 3}/La{sub 0.67}Sr{sub 0.33}MnO{sub 3} heterostructure was fabricated on LaAlO{sub 3} (111) substrate by pulsed laser deposition technology. A remarkable magneto-resistivity effect was detected at H = 1 T near the metal-insulator phase transition temperature (T{sub MI}) of La{sub 0.67}Sr{sub 0.33}MnO{sub 3}. The magneto-dielectric constant shows an anomaly near T{sub MI} of La{sub 0.67}Sr{sub 0.33}MnO{sub 3}, whereas the ferroelectric polarization increases under magnetic field and its variation shows the similar anomaly near T{sub MI} of La{sub 0.67}Sr{sub 0.33}MnO{sub 3}, which could be assigned to the important role of the phase transformation of La{sub 0.67}Sr{sub 0.33}MnO{sub 3}. The magnetic moment of the BiAlO{sub 3}/La{sub 0.67}Sr{sub 0.33}MnO{sub 3} heterostructure distinctly arises compared to the single La{sub 0.67}Sr{sub 0.33}MnO{sub 3} layer, probably on account of the spin-orbit coupling effect at the interface, and the relative magnetization variation also shows an anomaly near T{sub MI} of La{sub 0.67}Sr{sub 0.33}MnO{sub 3}. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Tritium biological effects and perspective of the biological study

International Nuclear Information System (INIS)

Komatsu, Kenshi

1998-01-01

Since tritium is an emitter of weak β-rays (5.7keV) and is able to bind to DNA, i.e., the most important genome component, the biological effects should be expected to be more profound than that of X-rays and γ-rays. When carcinogenesis, genetical effects and the detriments for fetus and embryo were used as a biological endpoint, most of tritium RBE (relative biological effectiveness) ranged from 1 to 2. The tritium risk in man could be calculated from these RBEs and γ-ray risk for human exposure, which are obtained mainly from the data on Atomic Bomb survivors. However, the exposure modality from environmental tritium should be a chronic irradiation with ultra low dose rate or a fractionated irradiation. We must estimate the tritium effect in man based on biological experiments alone, due to lack of such epidemiological data. Low dose rate experiment should be always accompanied by the statistical problem of data, since their biological effects are fairy low, and they should involve a possible repair system, such as adaptive response (or hormesis effect) and 'Kada effect' observed in bacteria. Here we discuss future works for the tritium assessment in man, such as (1) developing a high radiation sensitive assay system with rodent hybrid cells containing a single human chromosome and also (2) study on mammal DNA repair at molecular levels using a radiosensitive hereditary disease, Nijmegen Breakage Syndrome. (author)

Inactivation by oxidation and recruitment into stress granules of hOGG1 but not APE1 in human cells exposed to sub-lethal concentrations of cadmium

International Nuclear Information System (INIS)

Bravard, Anne; Campalans, Anna; Vacher, Monique; Gouget, Barbara; Levalois, Celine; Chevillard, Sylvie; Radicella, J. Pablo

2010-01-01

The induction of mutations in mammalian cells exposed to cadmium has been associated with the oxidative stress triggered by the metal. There is increasing evidence that the mutagenic potential of Cd is not restricted to the induction of DNA lesions. Cd has been shown to inactivate several DNA repair enzymes. Here we show that exposure of human cells to sub-lethal concentrations of Cd leads to a time- and concentration-dependent decrease in hOGG1 activity, the major DNA glycosylase activity responsible for the initiation of the base excision repair (BER) of 8-oxoguanine, an abundant and mutagenic form of oxidized guanine. Although there is a slight effect on the level of hOGG1 transcripts, we show that the inhibition of the 8-oxoguanine DNA glycosylase activity is mainly associated with an oxidation of the hOGG1 protein and its disappearance from the soluble fraction of total cell extracts. Confocal microscopy analyses show that in cells exposed to Cd hOGG1-GFP is recruited to discrete structures in the cytoplasm. These structures were identified as stress granules. Removal of Cd from the medium allows the recovery of the DNA glycosylase activity and the presence of hOGG1 in a soluble form. In contrast to hOGG1, we show here that exposure to Cd does not affect the activity of the second enzyme of the pathway, the major AP endonuclease APE1.

Dominant lethal mutations research in mice fed with irradiated black beams

International Nuclear Information System (INIS)

Andrade, Z.P.

1982-01-01

To evaluate the potential mutagenic effects of irradiated black beans (Phaseolus vulgaris) with conservation purpose, in germ cells of mice, dominant lethal assay were employed. Three groups of albino swiss male mice (S W-55) were fed with a normal ration, or unirradiated or irradiated (0,2; 0,5; 1; 5; 10; 15 e 20 KGy) test diets for eight weeks. After the feeding period the males were mated with groups of untreated females mice for four consecutive weeks. Numbers of pregnancy rates females were observed. The females were autopsied at mid-term pregnancy for evaluation of dominant lethal mutations. (author)

Skew scattering dominated anomalous Hall effect in Co<sub>x(MgO)>100-xsub> granular thin films

KAUST Repository

Zhang, Qiang; Wen, Yan; Zhao, Yuelei; Li, Peng; He, Xin; Zhang, Junli; He, Yao; Peng, Yong; Yu, Ronghai; Zhang, Xixiang

2017-01-01

We investigated the mechanism(s) of the anomalous Hall effect (AHE) in magnetic granular materials by fabricating 100-nm-thick thin films of Co<sub>x(MgO)>100-xsub> with a Co volume fraction of 34≤x≤100 using co

Effect of simultaneous cooling on microwave-assisted wet digestion of biological samples with diluted nitric acid and O{sub 2} pressure

Energy Technology Data Exchange (ETDEWEB)

Bizzi, Cezar A. [Departamento de Química, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul 97105-900 (Brazil); Nóbrega, Joaquim A. [Departamento de Química, Universidade Federal de São Carlos, São Carlos, São Paulo 13565-905 (Brazil); Barin, Juliano S. [Departamento de Tecnologia e Ciência dos Alimentos, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul 97105-900 (Brazil); Oliveira, Jussiane S.S.; Schmidt, Lucas; Mello, Paola A. [Departamento de Química, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul 97105-900 (Brazil); Flores, Erico M.M., E-mail: ericommf@gmail.br [Departamento de Química, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul 97105-900 (Brazil)

2014-07-21

Highlights: • Simultaneously cooling during microwave heating for improving digestion efficiency. • Maximum MW power delivered into cavity, improving the temperature in liquid phase. • Temperature gradient increases regeneration reaction of HNO{sub 3} in O{sub 2} rich atmosphere. • Digestion of several matrices using diluted HNO{sub 3} combined with O{sub 2} pressure. - Abstract: The present work evaluates the influence of vessel cooling simultaneously to microwave-assisted digestion performed in a closed system with diluted HNO{sub 3} under O{sub 2} pressure. The effect of outside air flow-rates (60–190 m{sup 3} h{sup −1}) used for cooling of digestion vessels was evaluated. An improvement in digestion efficiency caused by the reduction of HNO{sub 3} partial pressure was observed when using higher air flow-rate (190 m{sup 3} h{sup −1}), decreasing the residual carbon content for whole milk powder from 21.7 to 9.3% (lowest and highest air flow-rate, respectively). The use of high air flow-rate outside the digestion vessel resulted in a higher temperature gradient between liquid and gas phases inside the digestion vessel and improved the efficiency of sample digestion. Since a more pronounced temperature gradient was obtained, it contributed for increasing the condensation rate and thus allowed a reduction in the HNO{sub 3} partial pressure of the digestion vessel, which improved the regeneration of HNO{sub 3}. An air flow-rate of 190 m{sup 3} h{sup −1} was selected for digestion of animal fat, bovine liver, ground soybean, non fat milk powder, oregano leaves, potato starch and whole milk powder samples, and a standard reference material of apple leaves (NIST 1515), bovine liver (NIST 1577) and whole milk powder (NIST 8435) for further metals determination by inductively coupled plasma atomic emission spectroscopy (ICP-OES). Results were in agreement with certified values and no interferences caused by matrix effects during the determination step

"1H NMR-based metabolomics reveals sub-lethal toxicity of a mixture of diabetic and lipid-regulating pharmaceuticals on amphibian larvae

International Nuclear Information System (INIS)

Melvin, Steven D.; Habener, Leesa J.; Leusch, Frederic D.L.; Carroll, Anthony R.

2017-01-01

Highlights: • Pharmaceutical pollutants are a concern for eliciting adverse effects in wildlife. • Diabetes and lipid regulating drugs are widely used and poorly removed from sewage. • We explored the toxicity of a mixture of metformin, atorvastatin and bezafibrate on tadpoles. • Exposure caused increased growth and development but no effects on lipids or cholesterol. • "1H NMR-based metabolomics reveal increased lactic acid and BCAAs in exposed animals. - Abstract: Pharmaceuticals are widely used for the treatment of various physical and psychological ailments. Due to incomplete removal during sewage treatment many pharmaceuticals are frequently detected in aquatic waterways at trace concentrations. The diversity of pharmaceutical contaminants and potential for complex mixtures to occur makes it very difficult to predict the toxicity of these compounds on wildlife, and robust methods are therefore needed to explore sub-lethal effects. Metabolic syndrome is one of the most widespread health concerns currently facing the human population, and various drugs, including anti-diabetic medications and lipid- and cholesterol-lowering fibrates and statins, are widely prescribed as treatment. In this study, we exposed striped marsh frog (Limnodynastes peronii) tadpoles to a mixture of the drugs metformin, atorvastatin and bezafibrate at 0.5, 5, 50 and 500 μg/L to explore possible effects on growth and development, energy reserves (triglycerides and cholesterol), and profiles of small polar metabolites extracted from hepatic tissues. It was hypothesised that exposure would result in a general reduction in energy reserves, and that this would subsequently correspond with reduced growth and development. Responses differed from expected outcomes based on the known mechanisms of these compounds in humans, with no changes to hepatic triglycerides or cholesterol and a general increase in mass and condition with increasing exposure concentration. Deviation from the

Metformin is synthetically lethal with glucose withdrawal in cancer cells.

Science.gov (United States)

Menendez, Javier A; Oliveras-Ferraros, Cristina; Cufí, Sílvia; Corominas-Faja, Bruna; Joven, Jorge; Martin-Castillo, Begoña; Vazquez-Martin, Alejandro

2012-08-01

Glucose deprivation is a distinctive feature of the tumor microecosystem caused by the imbalance between poor supply and an extraordinarily high consumption rate. The metabolic reprogramming from mitochondrial respiration to aerobic glycolysis in cancer cells (the "Warburg effect") is linked to oncogenic transformation in a manner that frequently implies the inactivation of metabolic checkpoints such as the energy rheostat AMP-activated protein kinase (AMPK). Because the concept of synthetic lethality in oncology can be applied not only to genetic and epigenetic intrinsic differences between normal and cancer cells but also to extrinsic ones such as altered microenvironment, we recently hypothesized that stress-energy mimickers such as the AMPK agonist metformin should produce metabolic synthetic lethality in a glucose-starved cell culture milieu imitating the adverse tumor growth conditions in vivo. Under standard high-glucose conditions, metformin supplementation mostly caused cell cycle arrest without signs of apoptotic cell death. Under glucose withdrawal stress, metformin supplementation circumvented the ability of oncogenes (e.g., HER2) to protect breast cancer cells from glucose-deprivation apoptosis. Significantly, representative cell models of breast cancer heterogeneity underwent massive apoptosis (by >90% in some cases) when glucose-starved cell cultures were supplemented with metformin. Our current findings may uncover crucial issues regarding the cell-autonomous metformin's anti-cancer actions: (1) The offently claimed clinically irrelevant, non-physiological concentrations needed to observe the metformin's anti-cancer effects in vitro merely underlie the artifactual interference of erroneous glucose-rich experimental conditions that poorly reflect glucose-starved in vivo conditions; (2) the preferential killing of cancer stem cells (CSC) by metformin may simply expose the best-case scenario for its synthetically lethal activity because an increased

Application of TSH bioindicator for studying the biological efficiency of radiation

International Nuclear Information System (INIS)

Kim, Jin Kyu; Cebulska-Wasilewska, A.

1996-10-01

Dose response relationships for various endpoints (gene and lethal mutations, cell cycle alterations) in somatic cells of Tradescantia clone 4430 were established for X-rays and for mixed fast and thermal neutrons from Cf-252 source of KAERI and from U-120 cyclotron of INP. This was a pilot experiment to check if it is possible to establish the relative biological effectiveness values for Cf-252 irradiated TSH cells, with and without boron ion pretreatment, in conditions of mutual KAERI-INP experiment. When T-4430 was pretreated with boron ion, there was and enhancement in biological efficacy of neutron form Cf-252 source. 2 tabs., 7 figs., 7 refs. (Author)

BRINE SHRIMP LETHALITY TEST (BSLT DARI BERBAGAI FRAKSI EKSTRAK DAGING BUAH DAN KULIT BIJI MAHKOTA DEWA (Phaleria macrocarpa

Directory of Open Access Journals (Sweden)

Vivi Lisdawati

2012-10-01

Full Text Available Biological activity of a natural product involved in several certain characteristics will influence its pharmaceutical application. Secondary metabolites, considered as chemical compounds, are now thought to mediate plant defense mechanism by providing chemical barriers against animal and microbial predators. Brine Shrimp Lethality Test (BSLT method has been used as preliminary test for screening the activity of chemical compounds in n­ hexane, ethyl acetate, and methanol extracts from mesocarp and seeds of Phaleria macrocarpa, fam. Thymelaeaceae. BSLT method used shrimp larvas of Artemia salina L. to study the mortality effect that was caused by the sample extracts. All of crude extracts showed bioactivity with LC50 values from 0.16 to 11.83 µg/ml (baseline 1000 µg/ml. It means, at the concentration the crude extracts can cause 50% mortality of A. salina L. shrimp larvas, after 24 hours incubation. These results clearly indicate that crude extracts of P. macrocarpa showed high potential biological activity.

Humanitarian Algorithms : A Codified Key Safety Switch Protocol for Lethal Autonomy

OpenAIRE

Nyagudi, Nyagudi Musandu

2014-01-01

With the deployment of lethal autonomous weapons, there is the requirement that any such platform complies with the precepts of International Humanitarian Law. Humanitarian Algorithms[9: p. 9] ensure that lethal autonomous weapon systems perform military/security operations, within the confines of International Humanitarian Law. Unlike other existing techniques of regulating lethal autonomy this scheme advocates for an approach that enables Machine Learning. Lethal autonomous weapons must be ...

Lethal Surveillance: Drones and the Geo-History of Modern War

Science.gov (United States)

Kindervater, Katharine Hall

Interdisciplinary both in scope and method, my dissertation, Lethal Surveillance: Drones and the Geo-History of Modern War, examines the history of drone technology from the start of the 20th century to the present in order to understand the significance of the increasing centrality of drones to current American military engagements and security practices more generally. Much of the scholarship on drones and many other contemporary military technologies tends to view the technology as radically new, missing both the historical development of these objects as well as the perspectives and rationalities that are embedded in their use. For this research, I focused on three main periods of drone research and development: the early years of World War I and II in the UK, the Cold War, and the 1990s. In studying this history of the drone, I found that two key trends emerge as significant: the increasing importance of information to warfare under the rubric of intelligence, reconnaissance and surveillance; and a shift toward more dynamic, speedier, and individualized targeting practices. I argue that the widespread use of drones today thus represents the culmination of attempts in war to effectively link these two trends, creating a practice I call lethal surveillance -- with the armed Predator effectively closing the loop between identifying and killing targets. The concept of lethal surveillance, which in my dissertation I place squarely within the histories of modern scientific thinking and Western liberal governance, allows us to see how techniques of Western state power and knowledge production are merging with practices of killing and control in new ways, causing significant changes to both the operations of the state and to practices of war. Framing the drone through the lens of lethal surveillance, therefore, allows us to see the longer histories the drone is embedded in as well as other security practices it is connected to.

Effects of TiO{sub 2} nanoparticles on the NO{sub 2}{sup -} levels in cell culture media analysed by Griess colorimetric methods

Energy Technology Data Exchange (ETDEWEB)

Popescu, Traian, E-mail: tr.popescu@gmail.com [National Institute of Materials Physics (Romania); Lupu, Andreea R. [University of Bucharest, Faculty of Biology (Romania); Diamandescu, Lucian; Tarabasanu-Mihaila, Doina; Teodorescu, Valentin S. [National Institute of Materials Physics (Romania); Raditoiu, Valentin; Purcar, Violeta [National Research and Development Institute for Chemistry and Petrochemistry (ICECHIM) (Romania); Vlaicu, Aurel M. [National Institute of Materials Physics (Romania)

2013-02-15

The Griess assay has been used to determine the possible changes in the measured NO{sub 2}{sup -} concentrations induced by TiO{sub 2} nanoparticles in three types of nitrite-containing samples: aqueous NaNO{sub 2} solutions with known concentrations, and two types of cell culture media-Roswell Park Memorial Institute medium (RPMI-1640) and Dulbecco's Modified Eagle Medium (DMEM-F12) used either as delivered or enriched in NO{sub 2}{sup -} by NaNO{sub 2} addition. We have used three types of titania with average particle sizes between 10 and 30 nm: Degussa P25 and two other samples (undoped and Fe{sup 3+}-doped anatase TiO{sub 2}) synthesised by a hydrothermal route in our laboratory. The structural, morphological, optical and physicochemical characteristics of the used materials have been studied by X-ray diffraction, transmission electron microscopy (EDX), Moessbauer spectroscopy, Brunauer-Emmett-Teller nitrogen adsorption, UV-Vis reflectance spectroscopy, dynamic light scattering and diffuse reflectance infrared Fourier transform spectroscopy. The opacity and sedimentation behaviour of the studied TiO{sub 2} suspensions have been investigated by photometric attenuance measurements at 540 nm. To account for the photocatalytic properties of titania in a biologically relevant context, multiple Griess tests have been performed under controlled exposure to laboratory natural daylight illumination. The results show significant variations of light attenuance (associated with NO{sub 2}{sup -} concentrations in the Griess test) depending on the opacity, sedimentation behaviour, NO{sub 2}{sup -} adsorption and photocatalytic properties of the tested TiO{sub 2} nanomaterials. These findings identify material characteristics recommended to be considered when analysing the results of Griess tests performed in biological studies involving TiO{sub 2} nanoparticles.

Sensitivity of Vibrio cholerae cells to lethal and mutagenic effect of UV-irradiation mediated by plasmids

International Nuclear Information System (INIS)

Tiganova, I.G.; Evdokimova, N.M.; Aleshkin, G.I.

1988-01-01

The effect of UV-irradiation on Vibrio cholerae cells and its changes mediated by the plasmid R245 have been studied. Vibrio cholerae strains 569B and RV31 have been shown to be considerably more sensitive to lethal effect of UV-irradiation as compared with Escherichia coli and Salmonella typhimurium cells. Highly toxigenic strain 569B and practically atoxigenic strain RV31 have the same UV-sensitivity. Lethla effect of UV-irradiation on Vibrio cholerae cells is incresed when the irradiated cells are plated on enriched media. UV-induction of mutations was not registered in plasmidless strains of Vibrio cholerae. Plasmid R245 increase UV-resistance of vibrio cells and makes them UV-mutable

Cells, targets, and molecules in radiation biology

International Nuclear Information System (INIS)

Elkind, M.M.

1979-01-01

Cellular damage and repair are discussed with regard to inactivation models, dose-effect curves and cancer research, repair relative to damage accumulation, potentially lethal damage, repair of potentially lethal vs. sublethal damage, cell killing and DNA damage due to nonionizing radiation, and anisotonicity vs. lethality due to nonionizing radiation. Other topics discussed are DNA damage and repair in cells exposed to ionizing radiation, kinetics of repair of single-strand DNA breaks, effects of actinomycin D on x-ray survival curve of hamster cells, misrepair and lethality, and perspective and prospects

In vitro evaluation of relative biological effectiveness of 3MeV protons using γH2AX immuno-fluorescence

International Nuclear Information System (INIS)

Chaurasia, Rajesh K.; Desai, Utkarsha; Sirsath, K.B.; Bhat, N.N.; Sapra, B.K.; Gaur, Neeraj

2018-01-01

Use of charged particles for treating complicated tumors is gaining momentum. Their defined dose profile, near zero dose to normal tissue beyond tumour, skin sparing, more lethal effect than mutations, ability to focus beam with complex geometries are some of the advantages. Lack of scientific information on radiobiological efficacy, complexity and cost/maintenance of such facilities are hindering their use at present. Though a huge amount of time and resources are invested cancer treatment still primarily depends on chemotherapy and radiotherapy (γ-ray). Through this study we aim to demonstrate relative biological effectiveness of 3MeV proton beam with estimated LET of 13 keV/μm on cancerous mammalian cell line using highly reliable DNA double strand break γH2AX marker as a damage quantification tool

Non-Lethal Weapons Program

Science.gov (United States)

Sheets Frequently Asked Questions Non-Lethal Weapons FAQs Active Denial System FAQs Human Electro -Muscular Incapacitation FAQs Related Links Business Opportunities Contact JNLWD Congressional Engagement , Wednesday, Sept 20, 2017. The Active Denial System, blunt-impact munitions, dazzling lasers, LRAD 100X

Correlation between γ-ray-induced DNA double-strand breakage and cell killing after biologically relevant doses: analysis by pulsed-field gel electrophoresis

International Nuclear Information System (INIS)

Murray, D.

1994-01-01

We examined the degree of correlation between γ-ray-induced lethality and DNA double-strand breaks (dsbs) after biologically relevant doses of radiation. Radiation lethality was modified by treating 14 C-labelled Chinese hamster ovary cells with either of two aminothiols (WR-1065 or WR-255591) and the associated effect on dsb induction was determined by pulsed-field gel electrophoresis (PFGE). The use of phosphorimaging to analyse the distribution of 14 C-activity in the gel greatly improved the low-dose resolution of the PFGE assay. Both WR-1065 and WR-255591 protected against dsb induction and lethality to a similar extent after low doses of radiation. although this correlation broke down when supralethal doses were used to induce dsbs. Thus, the level of dsbs induced in these cells as measured by PFGE after survival-curve doses of γ-radiation is consistently predictive of the degree of lethality obtained, implying a cause-effect relationship between these two parameters and confirming previous results obtained using the neutral filter elution assay for dsbs. (author)

Effect of iron content on the structure and mechanical properties of Al{sub 25}Ti{sub 25}Ni{sub 25}Cu{sub 25} and (AlTi){sub 60-x}Ni{sub 20}Cu{sub 20}Fe{sub x} (x=15, 20) high-entropy alloys

Energy Technology Data Exchange (ETDEWEB)

Fazakas, É., E-mail: eva.fazakas@bayzoltan.hu [WPI-Advaced Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-Ku, Sendai 980-8577 (Japan); Wigner Research Center for Physics, Hungarian Academy of Sciences, H-1525, P.O.B. 49 (Hungary); Bay Zoltán Nonprofit Ltd., For Applied Research H-1116 Budapest, Fehérvári út 130 (Hungary); Zadorozhnyy, V. [National University of Science and Technology «MISIS», Leninsky prosp., 4, Moscow 119049 (Russian Federation); Louzguine-Luzgin, D.V. [WPI-Advaced Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-Ku, Sendai 980-8577 (Japan)

2015-12-15

Highlights: • Three new refractory alloys namely: Al{sub 25}Ti{sub 25}Ni{sub 25}Cu{sub 25}, Al{sub 22.5}Ti{sub 22.5}Ni{sub 20}Cu{sub 20}Fe{sub 15} and Al{sub 20}Ti{sub 20}Ni{sub 20}Cu{sub 20}Fe{sub 20}, were produced by induction-melting and casting. • This kind of alloys exhibits high resistance to annealing softening. • Most the alloys in the annealed state possess even higher Vickers microhardness than the as-cast alloys. • The Al{sub 22.5}Ti{sub 22.5}Ni{sub 20}Cu{sub 20}Fe{sub 15} and Al{sub 20}Ti{sub 20}Ni{sub 20}Cu{sub 20}Fe{sub 20} alloys annealed at 973 K show the highest compressive stress and ductility values. - Abstract: In this work, we investigated the microstructure and mechanical properties of Al{sub 25}Ti{sub 25}Ni{sub 25}C{sub u25} Al{sub 22.5}Ti{sub 22.5}Ni{sub 20}Cu{sub 20}Fe{sub 15} and Al{sub 20}Ti{sub 20}Ni{sub 20}Cu{sub 20}Fe{sub 20} high entropy alloys, produced by arc melting and casting in an inert atmosphere. The structure of these alloys was studied by X-ray diffractometry and scanning electron microscopy. The as-cast alloys were heat treated at 773, 973 and 1173 K for 1800 s to investigate the effects of aging on the plasticity, hardness and elastic properties. Compared to the conventional high-entropy alloys the Al{sub 25}Ti{sub 25}Ni{sub 25}Cu{sub 25}, Al{sub 22.5}Ti{sub 22.5}Ni{sub 20}Cu{sub 20}Fe{sub 15} and Al{sub 20}Ti{sub 20}Ni{sub 20}Cu{sub 20}Fe{sub 20} alloys are relatively hard and ductile. Being heat treated at 973 K the Al{sub 22.5}Ti{sub 22.5}Ni{sub 20}Cu{sub 20}Fe{sub 15} alloy shows considerably high strength and relatively homogeneous deformation under compression. The plasticity, hardness and elastic properties of the studied alloys depend on the fraction and intrinsic properties of the constituent phases. Significant hardening effect by the annealing is found.

Recovery from UV-induced potentially lethal damage in systemic lupus erythematosus skin fibroblasts

Energy Technology Data Exchange (ETDEWEB)

Zamansky, G B

1986-08-01

The repair of ultraviolet light-induced potentially lethal damage was investigated in density-inhibited skin fibroblast cell strains derived from patients with systemic lupus erythematosus. The effect of exposure to polychromatic ultraviolet light composed of environmentally relevant wavelengths or to the more commonly studied, short wavelength (254 nm) ultraviolet light was studied. Systemic lupus erythematosus cells, which are hypersensitive to ultraviolet light under growth promoting conditions, were able to repair potentially lethal damage as well as normal cells.

Recovery from UV-induced potentially lethal damage in systemic lupus erythematosus skin fibroblasts

International Nuclear Information System (INIS)

Zamansky, G.B.

1986-01-01

The repair of ultraviolet light-induced potentially lethal damage was investigated in density-inhibited skin fibroblast cell strains derived from patients with systemic lupus erythematosus. The effect of exposure to polychromatic ultraviolet light composed of environmentally relevant wavelengths or to the more commonly studied, short wavelength (254 nm) ultraviolet light was studied. Systemic lupus erythematosus cells, which are hypersensitive to ultraviolet light under growth promoting conditions, were able to repair potentially lethal damage as well as normal cells. (author)

Biological Effects of Ionizing Radiation

International Nuclear Information System (INIS)

Durand, J.L.

2000-01-01

The aim of this work is to verify the existence of the adaptive response phenomenon induced by low doses of ionizing radiation in living cells.A wild-type yeast Saccharomyces cerevisiae (Baker's yeast) was chosen as the biological target.As a parameter to quantify the sensibility of the target to radiation, the Lethal Dose 50 (LD50 ) was observed. In our experimental condition a value of (60 ± 1) Gy was measured for LD50 with Dose Rate of (0.44 ± 0.03) Gy/min. The method employed to show up the adaptive response phenomenon consisted in exposing the sample to low ''conditioning'' doses, which would initiate these mechanisms. Later the samples with and without conditioning were exposed to higher ''challenging'' doses (such as LD50), and the surviving fractions were compared. In order to maximize the differences, the doses and the time between irradiations were varied. The best results were obtained with both a conditioning dose of (0.44 ± 0.03) Gy and a waiting time of 2 hs until the application of the challenging dose. Following this procedures the 80% of the conditioned samples has survived, after receiving the application of the LD50. The adaptive response phenomenon was also verified for a wide range of challenging doses

Electric Field Effects on the Hidden Order of Microstructured URu<sub>2sub>Si>2sub>

Energy Technology Data Exchange (ETDEWEB)

Stritzinger, Laurel Elaine Winter [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mcdonald, Ross David [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Harrison, Neil [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Moll, P.J.W. [Max Planck Society, Dresden (Germany); Shekhter, A. [Florida State Univ., Tallahassee, FL (United States). National High Magnetic Field Lab. (MagLab); Ramshaw, B.J. [Cornell Univ., Ithaca, NY (United States); Bauer, Eric Dietzgen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-03-23

Despite being studied for over 30 years there is still continual interest in they heavy-fermion URu<sub>2sub>Si>2sub> due largely in part to the still disagreed upon origin of the so-called hidden-order (HO) state that arises below THO = 17.5 K. While both the application of pressure and high magnetic fields have been shown to suppress the HO state, one mechanism that has yet to be explored is the application of an electric field, most likely due to the difficulty of measuring such an effect in a metal. To overcome this challenge we have used focused ion beam (FIB) lithography to obtain the necessary sample geometry to create an electric field across a small section of the sample by applying a voltage. Our results suggest that at low temperatures the application of an electric field is able to suppress the hidden order state.

Biological effects of particle radiation

International Nuclear Information System (INIS)

Sakamoto, Kiyohiko

1988-01-01

Conventional radiations such as photons, gamma rays or electrons show several physical or biological disadvantages to bring tumors to cure, therefore, more and more attentions is being paid to new modalitie such as fast neutrons, protons, negative pions and heavy ions, which are expected to overcome some of the defects of the conventional radiations. Except for fast neutrons, these particle radiations show excellet physical dose localization in tissue, moreover, in terms of biological effects, they demonstrate several features compared to conventional radiations, namely low oxygen enhancement ratio, high value of relative biological effectiveness, smaller cellular recovery, larger therapeutic gain factor and less cell cycle dependency in radiation sensitivity. In present paper the biological effects of particle radiations are shown comparing to the effects of conventional radiations. (author)

Comparison of the biological effects of {sup 18}F at different intracellular levels

Energy Technology Data Exchange (ETDEWEB)

Kashino, Genro, E-mail: kashino@oita-u.ac.jp [Advanced Molecular Imaging Center, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Hasama-machi, Yufu City, Oita 879-5593 (Japan); Hayashi, Kazutaka; Douhara, Kazumasa [Advanced Molecular Imaging Center, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Hasama-machi, Yufu City, Oita 879-5593 (Japan); Kobashigawa, Shinko; Mori, Hiromu [Department of Radiology, Faculty of Medicine, Oita University, 1-1 Idaigaoka, Hasama-machi, Yufu City, Oita 879-5593 (Japan)

2014-11-07

Highlights: • We estimated the inductions of DNA DSB in cell treated with {sup 18}F-FDG. • We found that inductions of DNA DSB are dependent on accumulation of {sup 18}F in cell. • Accumulation of {sup 18}F in cell may be indispensable for risk estimation of PET. - Abstract: We herein examined the biological effects of cells treated with {sup 18}F labeled drugs for positron emission tomography (PET). The relationship between the intracellular distribution of {sup 18}F and levels of damaged DNA has yet to be clarified in detail. We used culture cells (Chinese Hamster Ovary cells) treated with two types of {sup 18}F labeled drugs, fluorodeoxyglucose (FDG) and fluorine ion (HF). FDG efficiently accumulated in cells, whereas HF did not. To examine the induction of DNA double strand breaks (DSB), we measured the number of foci for 53BP1 that formed at the site of DNA DSB. The results revealed that although radioactivity levels were the same, the induction of 53BP1 foci was stronger in cells treated with {sup 18}F-FDG than in those treated with {sup 18}F-HF. The clonogenic survival of cells was significantly lower with {sup 18}F-FDG than with {sup 18}F-HF. We concluded that the efficient accumulation of {sup 18}F in cells led to stronger biological effects due to more severe cellular lethality via the induction of DNA DSB.

Relative biological effectiveness (RBE) of alpha radiation in cultured porcine aortic endothelial cells.

Science.gov (United States)

Thomas, Patricia; Tracy, Bliss; Ping, Tilly; Baweja, Anar; Wickstrom, Mark; Sidhu, Narinder; Hiebert, Linda

2007-03-01

Northern peoples can receive elevated radiation doses (1- 10 mSv/y) from transfer of polonium-210 (210Po) through the lichen-caribou-human food chain. Ingested 210Po is primarily blood-borne and thus many of its short range alpha particles irradiate the endothelial cells lining the blood vessels. The relative biological effectiveness (RBE) of alpha particles vs. x-rays was examined in porcine aortic endothelial cells as a surrogate for understanding what might happen to human endothelial cells in northern populations consuming traditional foods. Cultured porcine aortic endothelial cells were exposed to x-ray and 210Po alpha particle radiation. Alpha irradiation was applied to the cell cultures internally via the culture medium and externally, using thin-bottomed culture dishes. The results given here are based on the external irradiation method, which was found to be more reliable. Dose-response curves were compared for four lethal endpoints (cell viability, live cell fraction, release of lactate dehydrogenase [LDH] and clonogenic survival) to determine the relative biological effectiveness (RBE) of alpha radiation. The alpha RBE for porcine cells varied from 1.6-21, depending on the endpoint: 21.2+/-4.5 for cell viability, 12.9+/-2.7 for decrease in live cell number, 5.3+/-0.4 for LDH release to the medium but only 1.6 +/-0.1 for clonogenic survival. The low RBE of 1.6 was due to x-ray hypersensitivity of endothelial cells at low doses.

Comparative study on the ability of IgG and F(ab')2 antivenoms to neutralize lethal and myotoxic effects induced by Micrurus nigrocinctus (coral snake) venom

OpenAIRE

León Montero, Guillermo; Stiles, Bradley G.; Alape Girón, Alberto; Rojas Céspedes, Gustavo; Gutiérrez, José María

1999-01-01

A comparative study was performed on the ability of IgG and F(ab')2 antivenoms to neutralize lethal and myotoxic activities of Micrurus nigrocinctus venom. Both antivenoms were adjusted to a similar neutralizing potency in experiments where venom and antivenoms were preincubated prior to injection. No significant differences were observed between IgG and F(ab')2 antivenoms concerning neutralization of lethal effect in rescue experiments, i.e., when antivenom was administered intravenously aft...

Lethal effects of solar radiation in proficient and deficient bacteria in repair systems; Efeitos letais da luz solar em bacterias proficientes e deficientes em reparos: acoes e interacoes

Energy Technology Data Exchange (ETDEWEB)

Sousa Neto, A de

1981-12-31

A study of the lethal action of solar radiation on strains of E.coli K12, proficient or deficient in repair systems, as well as the wild type strain gene products are involved in repair of damage induced by solar radiation. The inactivation of the various bacterial strains (normalized to a dose equivalent to radiation at a wavelength 254 nm) suggests that the more energetic wavelengths of the solar spectrum (290-320 nm) could be responsible for the primary damage that occurs in the DNA. The reduction in the shoulder of the survival curve in wild type strains in indicative of induction of sub-lethal damage in this region of the curve. Analysing solar inactivation curves of the bacterial strains (normalised by spore dosimetry) together with those of the same strains irradiated with UV at 254 nm, it was evident that 254 nm is not the ideal wavelength for comparison. This analysis also indicated that in addition to damage to DNA, other factors are involved in the solar radiation inactivation of wild type strains. (author).

Effect of microstructure on the high temperature mechanical properties of (CeO{sub 2}){sub 0.8}(GdO{sub 1.5}){sub 0.2} electrolytes

Energy Technology Data Exchange (ETDEWEB)

Sammes, N.M.; Zhang, Y. [Univ. of Waikato, Hamilton (New Zealand)

1996-12-31

CeO{sub 2}-based oxides have recently been shown to have great potential as electrolytes in medium temperature solid oxide fuel cell applications, primarily due to their high ionic conductivity. Steele et al., for example, have examined a cell of the type: O{sub 2}, La{sub 0.6}Sr{sub 0.4}Fe{sub 0.8}Co{sub 0.2}O{sub 3}{vert_bar}Ce{sub 0.9}Gd{sub 0.1}O{sub 1.95}{vert_bar}Ni-ZrO{sub 2}, H{sub 2}/H{sub 2}O at 715{degrees}C. Gd{sub 2}O{sub 3} doped CeO{sub 2} has been reported as having one of the highest oxygen ion conductivities of the ceria-based materials. An ionic conductivity of 8.3 x 10{sup -2} s/cm has been reported for (CeO{sub 2}){sub 0.8}(GdO{sub 1.5}){sub 0.2} at 800{degrees}C, which is approximately four times that of Y{sub 2}O{sub 3}-doped ZrO{sub 2}, at the same temperature. Although the electrical properties of the material have been examined in detail, very little work has considered the microstructural/property relationships, particularly in relation to the mechanical properties. It is well know that CeO{sub 2}-based materials are difficult to density and attempts have been performed to examine this. Preliminary studies have also been undertaken to examine the effect of sintering on the mechanical properties of the material. In this paper we examine the effect of microstructure on the high temperature mechanical properties of (CeO{sub 2}){sub 0.8}(GdO{sub 1.5}){sub 0.2}.

Electroshock weapons can be lethal!

Science.gov (United States)

Lundquist, Marjorie

2008-03-01

Electroshock weapons (EWs)-stun guns, tasers, riot shields-are electroconductive devices designed to safely incapacitate healthy men neuromuscularly, so they are called nonlethal or less-lethal. EW firms seeking large nonmilitary markets targeted law enforcement and corrections personnel, who began using EWs in prisons/jails and on public patrol in 1980 in the USA. This shifted the EW-shocked population from healthy soldiers to a heterogeneous mix of both sexes, ages 6-92, in a wide variety of health conditions! An EW operates by disrupting normal physiological processes, producing transient effects in healthy people. But if a person's health is sufficiently compromised, the margin of safety can be lost, resulting in death or permanent health problems. 325 people have died after EW shock since 1980. Did the EW cause these deaths? Evidence indicates that EWs do play a causal role in most such deaths. EWs can be lethal for people in diabetic shock^1 (hypoglycemia), which may be why Robert Dziekanski-a Polish immigrant to Canada-died so quickly after he was tasered at Vancouver Airport: not having eaten for over 10 hours, he likely was severely hypoglycemic. The EW death rate in North America is 30 times higher than need be, because EW users have not been properly trained to use EWs on a heterogeneous population safely! ^1J. Clinical Engineering 30(3):111(2005).

Giant magnetorefractive effect in La{sub 0.7}Ca{sub 0.3}MnO{sub 3} films

Energy Technology Data Exchange (ETDEWEB)

Granovskii, A. B., E-mail: granov@magn.ru [Moscow State University (Russian Federation); Sukhorukov, Yu. P., E-mail: suhorukov@imp.uran.ru; Telegin, A. V.; Bessonov, V. D. [Russian Academy of Sciences, Institute of Metal Physics, Ural Branch (Russian Federation); Gan' shina, E. A.; Kaul' , A. R.; Korsakov, I. E.; Gorbenko, O. Yu. [Moscow State University (Russian Federation); Gonzalez, J. [Universidad del Pais Vasco, Departamento Fisica de Materiales, Facultad de Quimica (Spain)

2011-01-15

Complex experimental investigations of the structural, optical, and magneto-optical properties (magnetotransmission, magnetoreflection, and transversal Kerr effect, as well as the magnetoresistance, of La{sub 0.7}Ca{sub 0.3}MnO{sub 3} epitaxial films indicate that magnetoreflection and magnetotransmission in manganite films can reach giant values and depend strongly on the magnetic and charge homogeneity of the films, their thickness, and spectral range under investigation. It has been shown that the optical enhancement of the magnetorefractive effect occurs in thin films as compared to manganite crystals. In the region of the minimum of the reflectance near the first phonon band, the resonance-like magnetorefractive effect has been observed, which is accompanied by change of the sign of the magnetoreflection. A model based on the theory of the magnetorefractive effect has been proposed to qualitatively explain this behavior.

The biological effectiveness of antiproton irradiation

DEFF Research Database (Denmark)

Holzscheiter, Michael H.; Bassler, Niels; Agazaryan, Nzhde

2006-01-01

ever measurements of the biological effectiveness of antiprotons. Materials and methods: V79 cells were suspended in a semi-solid matrix and irradiated with 46.7 MeV antiprotons, 48 MeV protons, or 60Co c-rays. Clonogenic survival was determined as a function of depth along the particle beams. Dose...... and particle fluence response relationships were constructed from data in the plateau and Bragg peak regions of the beams and used to assess the biological effectiveness. Results: Due to uncertainties in antiproton dosimetry we defined a new term, called the biologically effective dose ratio (BEDR), which...... has a higher relative biological effectiveness (RBE). Conclusion: We have produced the first measurements of the biological consequences of antiproton irradiation. These data substantiate theoretical predictions of the biological effects of antiproton annihilation within the Bragg peak, and suggest...

Effect of Er-doping on the structural and optical properties of Cd{sub 2}V{sub 2}O{sub 7}

Energy Technology Data Exchange (ETDEWEB)

Lozada-Morales, R.; Cid-Garcia, A.; Palomino-Merino, R. [Benemerita Universidad Autonoma de Puebla, Postgrado en Fisica Aplicada, Facultad de Ciencias Fisico-Matematicas, Av. 14, San Claudio, Col. San Manuel, Puebla (Mexico); Lopez-Calzada, G.; Jimenez-Sandoval, S. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro, Apartado Postal 1-798, Queretaro, Qro. 76001 (Mexico); Zayas, Ma.E. [Departamento de Investigacion en Fisica de la Universidad de Sonora, Edificio 3I, Blvd. Edificio 5 E, Luis Encinas s/n, Col. Centro, 83000 Hermosillo, Sonora (Mexico); Zelaya-Angel, O. [Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados, P.O. Box 14-740, Mexico D. F. 07360 (Mexico); Carmona-Rodriguez, J. [Instituto Tecnologico Superior de Poza Rica, Calle Luis Donaldo Colosio S/N, Col. Arroyo del Maiz, C.P. 93230, Poza Rica, Veracruz (Mexico); Rubio-Rosas, E. [Centro de Vinculacion Universitaria, Av. 14, San Claudio, Col. San Manuel, Puebla (Mexico); Portillo-Moreno, O. [Facultad de Ciencias Quimicas, Av. 14, San Claudio, Col. San Manuel, Puebla (Mexico)

2012-11-15

The melt-quenching method was used to prepare two groups of samples using CdO and V{sub 2}O{sub 5} as starting materials. Taking into account that a crystalline-amorphous phase transition would be expected for the CdO-V{sub 2}O{sub 5} system, a first batch was prepared varying the proportions of CdO and V{sub 2}O{sub 5} in the intervals 60-95 and 40-5 wt%, respectively. With the aim of investigating the effect of erbium in the phase transition and crystalline quality of the first group of samples, a second batch was fabricated with the same proportions of CdO and V{sub 2}O{sub 5}, with the addition of 5 wt% of Er(NO{sub 3})5H{sub 2}O as source of Er{sup 3+} ions. It was found that crystalline or amorphous samples could be obtained depending on the relative concentrations of CdO and V{sub 2}O{sub 5}, and that the borderline between amorphous and crystalline samples was affected by the incorporation of Er. From X-ray diffraction, it was possible to identify the formation of the ternary compound Cd{sub 2}V{sub 2}O{sub 7} in the crystalline cases. The Raman and infrared bands in these samples were in agreement with the lattice modes of Cd{sub 2}V{sub 2}O{sub 7}. Additionally, an improvement in the crystalline quality of Cd{sub 2}V{sub 2}O{sub 7} was obtained for the Er-doped samples. The effect of the local environment around the Er{sup 3+} ions on the room temperature photoluminescence was also investigated for the amorphous and crystalline samples. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Magnetoelastic effects in La{sub 0.7}Sr{sub 0.3−x}Ca{sub x}MnO{sub 3} nanocrystalline perovskites

Energy Technology Data Exchange (ETDEWEB)

Tabatabai Yazdi, Sh., E-mail: sh_tabatabai3@yahoo.com [Department of Physics, Faculty of Sciences, Ferdowsi University of Mashhad, Mashhad 91755-1436 (Iran, Islamic Republic of); Iranmanesh, P. [Department of Physics, Vali-e-Asr University of Rafsanjan, 77139-36417 Rafsanjan (Iran, Islamic Republic of)

2014-09-01

La{sub 0.7}Sr{sub 0.3−x}Ca{sub x}MnO{sub 3} (x=0, 0.1, 0.2 and 0.3) nanoparticles, prepared by sol–gel method, were studied by means of X-ray diffraction, transmission electron microscopy, thermal expansion and magnetostriction measurements. It was revealed that samples of low Ca concentration (x≤0.1) crystallize in rhombohedral perovskite structure with R-3c space group, and by increasing x, smaller Ca radius causes the lattice to convert to orthorhombic structure (space group of Pbnm). The results exhibit an anomalous behavior in the thermal expansion behavior of all samples, as well as temperature dependence of their volume magnetostriction being related to the presence of a conductive magnetic two-phase state at temperatures higher than T{sub C}. Moreover, the magnitude of this magnetovolume effect increases with x due to smaller Ca size, which softens the crystal lattice. The results show that Ca substitution results in weakening the double-exchange interaction and consequently reducing T{sub C}, as well as decreasing the magnetic anisotropy. Furthermore, our nanocrystalline samples have a relatively lower T{sub C}, compared with the reported values for similar compounds with larger particle size. Among them, the sample with x=0.2 possess T{sub C} value of about room temperature; to say by partial substitution of Ca for Sr we succeeded in adjusting the transition temperature of this series of manganites which was a main motivation for this research. - Highlights: • Magnetoelastic properties of La{sub 0.7}Sr{sub 0.3−x}Ca{sub x}MnO{sub 3} nanocrystalline samples are investigated. • Substitution of Sr by Ca causes structure to convert from rhombohedral to orthorhombic perovskite. • Considerable magnetovolume anomalies are revealed due to presence of conductive MTPS above T{sub C}. • Ca softens the crystal lattice and intensifies the magnetovolume effects. • Ca reduces T{sub C} and magnetic anisotropy of compounds by weakening DE interactions.

Josephson effect in Al/Bi{sub 2}Se{sub 3}/Al coplanar hybrid devices

Energy Technology Data Exchange (ETDEWEB)

Galletti, L., E-mail: luca.galletti@unina.it [Dipartimento di Scienze Fisiche, Università degli Studi di Napoli Federico II, I-80126 Napoli (Italy); CNR-SPIN Napoli, Complesso Universitario di Monte Sant’Angelo, 80126 Napoli (Italy); Charpentier, S. [Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg (Sweden); Lucignano, P.; Massarotti, D. [Dipartimento di Scienze Fisiche, Università degli Studi di Napoli Federico II, I-80126 Napoli (Italy); CNR-SPIN Napoli, Complesso Universitario di Monte Sant’Angelo, 80126 Napoli (Italy); Arpaia, R. [Dipartimento di Scienze Fisiche, Università degli Studi di Napoli Federico II, I-80126 Napoli (Italy); Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg (Sweden); Tafuri, F. [CNR-SPIN Napoli, Complesso Universitario di Monte Sant’Angelo, 80126 Napoli (Italy); Dipartimento di Ingegneria Industriale e dell’Informazione, Seconda Università di Napoli, I-81031 Aversa (CE) (Italy); Bauch, T. [Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg (Sweden); Suzuki, Y. [University of Tsukuba, Institute of Materials Science, Tsukuba 305, Ibaraki (Japan); Tagliacozzo, A. [Dipartimento di Scienze Fisiche, Università degli Studi di Napoli Federico II, I-80126 Napoli (Italy); Kadowaki, K. [University of Tsukuba, Institute of Materials Science, Tsukuba 305, Ibaraki (Japan); Lombardi, F. [Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296 Göteborg (Sweden)

2014-08-15

Highlights: • Superconducting proximity effect induced in Al/Bi{sub 2}Se{sub 3}/Al coplanar hybrid devices. • Comparative study of Al/Bi{sub 2}Se{sub 3} interfaces with various buffer layers. • Towards a Josephson super-current through the edge states of topological insulators. - Abstract: The edge states of Topological Insulators (TI) are protected against backscattering, thanks to the topological properties arising from their band structure. Coupling a TI to a superconductor (S) can induce unconventional effects, including the creation of Majorana bound states (MBS). The fabrication of coplanar hybrid devices is a fundamental step to pave the way to the understanding of proximity effects in topologically non-trivial systems, and to a large variety of experiments aimed at the possible detection of MBS. We discuss the feasibility and some relevant properties of Al–Bi{sub 2}Se{sub 3}–Al coplanar proximity devices. Special attention is devoted to the design of the junction, aimed at enhancing the coupling between the electrodes and the TI.

Comparative effects of herbicides on photosynthesis and growth of tropical estuarine microalgae

Energy Technology Data Exchange (ETDEWEB)

Magnusson, Marie [AIMS at JCU, Australian Institute of Marine Science, School of Marine and Tropical Biology, James Cook University, Townsville, QLD 4811 (Australia); School of Marine and Tropical Biology, James Cook University, Douglas Campus, Townsville 4811 (Australia); Heimann, Kirsten [School of Marine and Tropical Biology, James Cook University, Douglas Campus, Townsville 4811 (Australia)], E-mail: Kirsten.Heimann@jcu.edu.au; Negri, Andrew P. [Australian Institute of Marine Science, PMB 3 Townsville MC, QLD 4810 (Australia)

2008-09-15

Pulse amplitude modulation (PAM) fluorometry is ideally suited to measure the sub-lethal impacts of photosystem II (PSII)-inhibiting herbicides on microalgae, but key relationships between effective quantum yield [Y(II)] and the traditional endpoints growth rate ({mu}) and biomass increase are unknown. The effects of three PSII-inhibiting herbicides; diuron, hexazinone and atrazine, were examined on two tropical benthic microalgae; Navicula sp. (Heterokontophyta) and Nephroselmis pyriformis (Chlorophyta). The relationships between Y(II), {mu} and biomass increase were consistent (r{sup 2} {>=} 0.90) and linear (1:1), validating the utility of PAM fluorometry as a rapid and reliable technique to measure sub-lethal toxicity thresholds of PSII-inhibiting herbicides in these microalgae. The order of toxicity (EC{sub 50} range) was: diuron (16-33 nM) > hexazinone (25-110 nM) > atrazine (130-620 nm) for both algal species. Growth rate and photosynthesis were affected at diuron concentrations that have been detected in coastal areas of the Great Barrier Reef.

Autonomous Control, Climate and Environmental Changes Effects ...

African Journals Online (AJOL)

Autonomous Control, Climate and Environmental Changes Effects on Trypanosomiasis in Sub-Saharan Africa: A Review. ... African trypanosomiasis is a parasitic disease that causes serious economic losses in livestock due to anemia, loss of condition and emaciation. The disease when neglected is lethal and untreated ...

Non-Lethal Weapons: Opportunities for R&D

Science.gov (United States)

2004-12-01

during the Vietnam War. US; emulsifying agents are used in food processing, drilling fluids, cosmetics , pharmaceuticals, heavy- duty cleaners, textile...conducted in a professional manner, with no threat to public safety or the environment. 11 References [1] Fenton , G., (2001). NLW Technology Taxonomy...W.A., Mason, R.L., Collins, K.R., (2000). Non-Lethal Applicants of Slippery Substances. NDIA Non-Lethal Defense IV. [24] Fenton , G., (2000). Overview

The role of carbonic anhydrase in C<sub>4sub> photosynthesis

Energy Technology Data Exchange (ETDEWEB)

Studer, Anthony [Life Sciences Research Foundation, Baltimore, MD (United States)

2015-10-01

Current pressures on the global food supply have accelerated the urgency for a second green revolution using novel and sustainable approaches to increase crop yield and efficiency. This proposal outlines experiments to address fundamental questions regarding the biology of C<sub>4sub> photosynthesis, the method of carbon fixation utilized by the most productive food, feed and bioenergy crops. Carbonic anhydrase (CA) has been implicated in multiple cellular functions including nitrogen metabolism, water use efficiency, and photosynthesis. CA catalyzes the first dedicated step in C<sub>4sub> photosynthesis, the hydration of CO<sub>2sub> into bicarbonate, and is potentially rate limiting in C<sub>4sub> grasses. Using insertional mutagenesis, we have generated CA mutants in maize, and propose the characterization of these mutants using phenotypic, physiological, and transcriptomic profiling to assay the plant’s response to altered CA activity. In addition, florescent protein tagging experiments will be employed to study the subcellular localization of CA paralogs, providing critical data for modeling carbon fixation in C<sub>4sub> plants. Finally, I propose parallel experiments in Setaria viridis to explore its relevance as model C<sub>4sub> grass. Using a multifaceted approach, this proposal addresses important questions in basic biology, as well as the need for translation research in response to looming global food challenges.

Models for pulmonary lethality and morbidity after irradiation from internal and external sources

International Nuclear Information System (INIS)

Scott, B.R.; Filipy, R.E.; Hahn, E.F.

1989-05-01

This report provides a hazard-function model for estimating the risk of death from radiation pneumonitis and/or pulmonary fibrosis following a light-water nuclear power accident. A similar model is also provided for estimating the prevalence of respiratory functional morbidity among those that survive death from acute effects. Hazard-function models for lethality and for morbidity were constructed using the cumulative hazard estimator H, which is related to the risk estimator R through the equation R = 1-exp(-H). The estimator H can be calculated using information provided in the report. The method of calculation depends on the exposure scenario. In general, the total normalized dose X for lethality or for morbidity is calculated. For lethality, X = 1 corresponds to a median lethal dose (LD 50 ); for morbidity, X = 1 corresponds to a median effective dose (ED 50 ). H is related to X by the equation H = 1n(2)X/sup V/, where V depends on the type of radiation (or radiations) involved. Contributions to X can arise from each of two main modes of exposure: (1) brief exposure of the lung, at a relatively high dose rate, to mainly external gammas, followed by (2) chronic internal alpha, and/or beta, and/or gamma irradiation of the lung. Equations are provided for calculating the contributions to X from both modes of exposure. 73 refs., 16 figs., 2 tabs

Effects of Ni{sub 3}Sn{sub 4} and (Cu,Ni){sub 6}Sn{sub 5} intermetallic layers on cross-interaction between Pd and Ni in solder joints

Energy Technology Data Exchange (ETDEWEB)

Baek, Yong-Ho [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Division of Advanced Circuit Interconnect, Samsung Electro-Mechanics Co., Ltd., Suwon 443-743 (Korea, Republic of); Chung, Bo-Mook [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Department of Research and Development, KPM TECH, Ansan 425-090 (Korea, Republic of); Choi, Young-Sik [Division of Advanced Circuit Interconnect, Samsung Electro-Mechanics Co., Ltd., Suwon 443-743 (Korea, Republic of); Choi, Jaeho [Department of Advanced Metal and Materials Engineering, Gangneung-Wonju National University, Gangneung 210-702 (Korea, Republic of); Huh, Joo-Youl, E-mail: jyhuh@korea.ac.kr [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

2013-12-05

Highlights: •Ni{sub 3}Sn{sub 4} acts as a source of Ni atoms, leading to a strong cross-interaction with Pd. •(Cu,Ni){sub 6}Sn{sub 5} is an effective Ni diffusion barrier, inhibiting Pd resettlement. •Dissolution kinetics of (Pd,Ni)Sn{sub 4} was interpreted based on the Sn–Ni–Pd isotherm. •Cu addition to solder alleviates the (Pd,Ni)Sn{sub 4}-related risk of reliability deterioration. -- Abstract: We examined the effects of layers of intermetallic compound (IMC) Ni{sub 3}Sn{sub 4} and (Cu,Ni){sub 6}Sn{sub 5} formed at the solder/Ni interface, on the cross-interactions between Pd and Ni during solid-state aging and reflow soldering. Two types of diffusion couples, Pd/Sn/Ni and Pd/Sn–Cu/Ni, were aged at 150 °C to study the solid-state interactions. In contrast to the Pd/Sn/Ni couples in which a Ni{sub 3}Sn{sub 4} layer formed at the Ni interface, the Pd/Sn–Cu/Ni couple where a (Cu,Ni){sub 6}Sn{sub 5} layer formed at the Ni interface exhibited no significant interaction between Pd and Ni. The (Cu,Ni){sub 6}Sn{sub 5} layer acted as an effective barrier against Ni diffusion and thus inhibited the resettlement of (Pd,Ni)Sn{sub 4} onto the Ni interface. For the interaction during reflow, Sn–3.5Ag and Sn–3.0Ag–0.5Cu solder balls were isothermally reflowed on an electroless Ni(P)/electroless Pd/immersion Au (ENEPIG) surface finish at 250 °C, and the dissolution kinetics of the (Pd,Ni)Sn{sub 4} particles converted from the 0.2-μm-thick Pd-finish layer were examined. The spalled (Pd,Ni)Sn{sub 4} particles very quickly dissolved into the molten solder when the IMC layer formed on the Ni substrate was (Cu,Ni){sub 6}Sn{sub 5} rather than Ni{sub 3}Sn{sub 4}. The dependence of the dissolution kinetics of the spalled (Pd,Ni)Sn{sub 4} particles on the IMC layers was rationalized on the basis of a Sn–Ni–Pd isotherm at 250 °C. The present study suggests that the formation of a dense (Cu,Ni){sub 6}Sn{sub 5} layer at the solder/Ni interface can effectively

Effects of dopants on the amorphous-to-fcc transition in Ge{sub 2}Sb{sub 2}Te{sub 5} thin films

Energy Technology Data Exchange (ETDEWEB)

Privitera, S. [R and D Department, Micro, Power, Analog (MPA) Group, STMicroelectronics, MP8, Stradale Primosole 50, 95121 Catania (Italy)]. E-mail: stefania.privitera@st.com; Rimini, E. [Istituto di Microelettronica e Microsistemi (IMM), Consiglio Nazionale delle Ricerche (CNR), Stradale Primosole 50, 95121 Catania (Italy); Bongiorno, C. [Istituto di Microelettronica e Microsistemi (IMM), Consiglio Nazionale delle Ricerche (CNR), Stradale Primosole 50, 95121 Catania (Italy); Pirovano, A. [FTM, Advanced R and D, NVMTD, STMicroelectronics, Via Olivetti 2, 20041, Agrate Brianza (Italy); Bez, R. [FTM, Advanced R and D, NVMTD, STMicroelectronics, Via Olivetti 2, 20041, Agrate Brianza (Italy)

2007-04-15

The amorphous-to-crystal transition has been studied through in situ resistance measurements in Ge{sub 2}Sb{sub 2}Te{sub 5} thin films doped by ion implantation with nitrogen, oxygen or fluorine at different concentrations. Enhancement of the thermal stability has been observed in O and N amorphous doped Ge{sub 2}Sb{sub 2}Te{sub 5}. Larger effects have been found in the case of nitrogen doping. On the contrary, doping with Fluorine produced a decrease in the crystallization temperature. The electrical properties have been related to the structural phase change through in situ transmission electron microscopy analysis. The comparison between undoped and doped Ge{sub 2}Sb{sub 2}Te{sub 5} shows that the introduction of oxygen or nitrogen modifies in a different way the kinetics of the amorphous-to-fcc transition and gives new insight on the effects of doping with light elements in GeSbTe alloys.

Hypoxial death inferred from thermally induced injuries at upper lethal temperatures, in the banded killifish, Fundulus diaphanus (LeSueur)

Energy Technology Data Exchange (ETDEWEB)

Rombough, P J; Garside, E T

1977-10-01

Banded killifish, Fundulus diaphanus (LeSueur), acclimated to 25/sup 0/C were subjected to upper lethal temperatures using a 10,000 min bioassay procedure. The incipient upper lethal temperature (LT/sub 50/) was about 34.5/sup 0/C. Histologic examination of heat-treated fish revealed no obvious injury to the heart, spleen, trunk musculature, eye, naris, integument, or digestive tract. Thermal stress induced progressive injury to the gills characterized by subepithelial edema, congestion of lamellar capillaries, and delamination of the respiratory epithelium from the pillar cell system. Areas of necrosis were observed in the lobus inferior of the hypothalamus and in the medulla oblongata. The pseudobranch epithelium was necrotic. Fatty change occurred in the liver. Acinar cells of the pancreas appeared autolytic and adjacent blood vessels damaged. Degenerative tubular changes and contracted glomerular tufts were noted in the kidney. The ovary was extremely temperature sensitive and displayed severe injury to oocytes and follicular cells after relatively short exposure to temperatures near the LT/sub 50/. It is proposed that primary thermally induced injury is to the gills. This results in abnormal gas exchange and osmoregulation and leads to pathologic changes in other tissues. Hypoxia of the central nervous system appears to be the ultimate cause of death.

Lethal synergy involving bicyclomycin: an approach for reviving old antibiotics.

Science.gov (United States)

Malik, Muhammad; Li, Liping; Zhao, Xilin; Kerns, Robert J; Berger, James M; Drlica, Karl

2014-12-01

One way to address the growing problem of antimicrobial resistance is to revive old compounds that may have intrinsic lethal activity that is obscured by protective factors. Bicyclomycin is an old inhibitor of the Rho transcription terminator that by itself shows little rapid lethal activity. However, bicyclomycin participates in bacteriostatic synergy, which raises the possibility that conditions for lethal synergy may exist, perhaps through a suppression of protective factors. Bicyclomycin was combined with bacteriostatic inhibitors of gene expression, and bactericidal activity was measured with several cultured Gram-negative pathogens. When used alone, bicyclomycin failed to rapidly kill growing cultures of Escherichia coli; however, the additional presence of bacteriostatic concentrations of tetracycline, chloramphenicol or rifampicin led to rapid killing. Four other pathogen species, Acinetobacter baumannii, Klebsiella pneumoniae, Salmonella enterica serotype Typhimurium and Shigella dysenteriae, also exhibited enhanced killing when bicyclomycin was combined with tetracycline or rifampicin. This lethal synergy was achieved at low concentrations (slightly above the MIC) for all agents tested in combinations. Follow-up work with E. coli indicated that lethal synergy arose from a blockage of transcription elongation. Moreover, lethal synergy was reduced when bicyclomycin was added 60 min before tetracycline, suggesting that bicyclomycin induces a protective factor. The action of bicyclomycin illustrates the potential present in a largely abandoned antibacterial agent; it exhibits lethal synergy when coadministered with known, bacteriostatic inhibitors of gene expression. The identification of protective factors, which are currently uncharacterized, may reveal new ways to promote the lethal action of some old antibiotics. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved

Crystallization of Zr<sub>2sub>Pd_xCu>1-xsub> and Zr<sub>2sub>Ni_xCu>1-xsub> Metallic Glass

Energy Technology Data Exchange (ETDEWEB)

Xu, Min [Iowa State Univ., Ames, IA (United States)

2008-01-01

One interesting aspect of rretallic glasses is the numerous instances of the deviation of the phase selection from the amorphous state to thermodynamically stable phases during the crystallization process. Their devitrification pathways allow us to study the relationship between the original amorphous structure and their crystalline counter parts. Among the various factors of phase selections, size and electronic effects have been most extensively studied. Elucidating the phase selection process of a glassy alloy will be helpful to fill in the puzzle of the changes from disordered to ordered structures. In this thesis, Two model Zr<sub>2sub>Pd_xCu>1-xsub> and Zr<sub>2sub>Ni_xCu>1-xsub> (x = 0, 0.25, 0.5, 0.75 and 1) glassy systems were investigated since: (1) All of the samples can be made into a homogenous metallic glass; (2) The atomic radii differ from Pd to Cu is by 11%, while Ni has nearly the identical atomic size compare to Cu. Moreover, Pd and Ni differ by only one valence electron from Cu. Thus, these systems are ideal to test the idea of the effects of electronic structure and size factors; (3) The small number of components in these pseudo binary systems readily lend themselves to theoretical modeling. Using high temperature X-ray diffraction (HTXRD) and thermal analysis, topological, size, electronic, bond and chemical distribution factors on crystallization selections in Zr<sub>2sub>Pd_xCu>1-xsub> and Zr<sub>2sub>Ni_xCu>1-xsub> metallic glass have been explored. All Zr<sub>2sub>Pd_xCu>1-xsub> compositions share the same Cu11b phase with different pathways of meta-stable, icosahedral quasicrystalline phase (i-phase), and C16 phase formations. The quasicrystal phase formation is topologically related to the increasing icosahedral short range order (SRO) with Pd content in Zr<sub>2sub>Pd_xCu>1-xsub> system. Meta-stable C16 phase is competitive with