WorldWideScience

Sample records for artemia franciscana strains

  1. Assessment of endemic microalgae as potential food for Artemia franciscana culture

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    Juan M Pacheco-Vega

    2015-03-01

    Full Text Available In this study, five microalgal strains were isolated from Bahía de La Paz, Baja California Sur, Mexico and identified as Grammatophora sp., Navícula sp., Rhabdonema sp., Schizochytrium sp., and Nitzschia sp., and their evaluation as potential food for Artemia franciscana. The isolated strains were cultured outdoors and harvested after four days. Chaetoceros muelleri was cultured under laboratory conditions and used as control. The protein, lipid, and carbohydrate composition and the fatty acid profiles of the strains were determined by gas chromatography. To assess the effect of microalgal strains on A. franciscana, decapsulated cysts were cultured at outdoor conditions in 15 L containers. The experiment was conducted for twelve days. Samples from the five different feeding treatments were taken at the beginning and end of the experiment to assess number, size, and weight of Artemia larvae. Treatment with Rhabdonema sp. showed larvae with a lower percentage of polyunsaturated fatty acids (PUFAs while Grammatophora sp. showed those with the greatest PUFA proportion, even more than those fed Chaetoceros muelleri (control. Larvae consuming Schizochytrium sp. had no docosahexanoic (DHA nor eicosapentaenoic (EPA fatty acid content. Growth and survival of A. franciscana did not show significant differences among feed treatments, except when it was fed Nitzschia sp., showing lower survival and dry weight. Treatment based on Schizochytrium sp. and Rhabdonema sp. had a greater A. franciscana size but reduced dry weight; additional tests including two or more algal species for every treatment should be carried out to determine the best yield.

  2. Production dynamics of Brine Shrimp (Artemia franciscana) in the San Francisco Bay National Wildlife Refuge

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    US Fish and Wildlife Service, Department of the Interior — Abundance, stage structure and population dynamics of brine shrimp Artemia franciscana in pond M4 of the San Francisco Bay National Wildlife Refuge were documented...

  3. Marine Lactobacillus pentosus H16 protects Artemia franciscana from Vibrio alginolyticus pathogenic effects.

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    Garcés, M E; Sequeiros, C; Olivera, N L

    2015-02-10

    Vibrio alginolyticus is an opportunistic pathogen which may affect different aquatic organisms. The aim of this study was to assess the probiotic properties and the protective mode of action of Lactobacillus pentosus H16 against V. alginolyticus 03/8525, through in vitro and in vivo studies using Artemia franciscana (hereafter Artemia). This strain showed antimicrobial activity against V. alginolyticus 03/8525 and Aeromonas salmonicida subsp. salmonicida ATCC33658 possibly related to lactobacilli organic acid production. It was able to survive at high rainbow trout bile concentrations and showed high selective adhesion to rainbow trout mucus (1.2×10(5)±8.0×10(3) cells cm(-2)). H16 outcompeted V. alginolyticus 03/8525 and A. salmonicida subsp. salmonicida ATCC33658, greatly reducing their adherence to rainbow trout mucus (64.8 and 74.1%, respectively). Moreover, H16 produced a cell-bound biosurfactant which caused an important decrease in the surface tension. H16 also protected Artemia nauplii against mortality when it was administered previous to V. alginolyticus 03/8525 inoculation. Furthermore, H16 bioencapsulated in Artemia, suggesting that it is possible to use live carriers in its administration. We conclude that the ability of L. pentosus H16 to selectively adhere to mucosal surfaces and produce cell-bound biosurfactants, displacing pathogenic strains, in addition to its antimicrobial activity, confer H16 competitive advantages against pathogens as demonstrated in in vivo challenge experiments. Thus, L. pentosus H16, a marine bacterium from the intestinal tract of hake, is an interesting probiotic for Artemia culture and also has the potential to prevent vibriosis in other aquaculture activities such as larvae culture and fish farming. PMID:25667335

  4. Peningkatan Kuantitas dan Kualitas Kista Artemia franciscana setelah Pemberian Silase Ikan

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    ENDAH BUDI SULISTYOWATI

    2007-11-01

    Full Text Available Artemia is one of live feed needed in aquaculture as fishes and crustacean. Commercially, Artemia usually sold in dry cysts which can kept for years. The aim of this research were to know increasing quantity and quality A. franciscana cysts after exposing various concentration of fish silage as artificial food and to know optimal concentration of fish silage that can increase quantity and quality A. franciscana cysts. This research was done in Laboratory of Live Feed BBPBAP Jepara Central Java. This research was conducted by 5 treatments. Treatments were grouped based on amount of concentration given, i.e: control (coconut cake with concentrate 10 g/m3, fish silage concentrate 10, 20, 30, and 40 g/m3. Parameter investigated were number of cysts produced by individual female A. franciscana, diameter of A. franciscana cysts, hatching percentage, and hatching rate of A. franciscana cysts. Data were analyzed using ANOVA and continued using Tukeys test at significant level 5%. The result of this research showed that exposing fish silage can increase quantity and quality A. franciscana cysts. They were increase number of cysts production by individual females, decrease cysts diameter, increase hatching percentage and hatching rate. Optimal concentration of fish silage on increase quantity and quality of A. franciscana cysts was 20 g/m3.

  5. Potential utilization of Artemia franciscana eggs as food for Coleomegilla maculata

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    We tested the hypothesis that Artemia franciscana Kellogg (brine shrimp, Anostraca: Artemiidae) eggs are suitable factitious, i.e., alternative, food to support the life history of a predatory ladybird beetle, Coleomegilla maculata DeGeer (Coleoptera: Coccinellidae). Using progeny from a stock colo...

  6. [Composition of fat acids in three Mexican populations of Artemia franciscana from epicontinental waters].

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    Malpica Sánchez, Aída; Castro Barrera, Thalía; Sandoval Trujillo, Horacio; Castro Mejía, Jorge; De Lara Andrade, Ramón; Castro Mejía, Germán

    2004-03-01

    In this paper is presented the percentage of fatty acids composition of three Artemia franciscana Mexican populations of epicontinentals waters; two are from natural environments (Coahuila and San Luis Potosf) and one (Texcoco) is a culture fed with Spirulina. Determination of fatty acids composition in each population, was performed by extraction of total lipid by the soxhlet method and the fatty acids methyl esters were determined by gas chromatography. The results show that Artemia of Texcoco contains the six fatty acids recommended for the culture of fish and crustaceans (16:0; 16:1; 18:1; 18:2w6; 18:3w3 and 20:5w3); Artemia from San Luis Potosi showed the poorest content in these acids and Artemia from Coahuila, although it showed a wide profile, it lacks the linolenic acid. When comparing results among the three populations with ecological data that have been published, it can be pointed out that the environment is decisive for this crustacean; Artemia from Texcoco fed with Spirulina showed the largest variety of fatty acids; the other two populations are wild, and lives in different habitats, Artemia of Coahuila is found in waters that are rich in sulfates and Artemia of San Luis Potosf lives in evaporation saltern ponds, built with stone blocks and therefore with scarce phytoplankton growth. Both Artemia populations showed deficiencies in essential fatty acids, mainly the last one.

  7. Maladaptive Sex Ratio Adjustment in the Invasive Brine Shrimp Artemia franciscana.

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    Lievens, Eva J P; Henriques, Gil J B; Michalakis, Yannis; Lenormand, Thomas

    2016-06-01

    Sex allocation theory is often hailed as the most successful area of evolutionary theory due to its striking success as a predictor of empirical observations [1]. Most naturally occurring sex ratios can be explained by the principle of equal investment in the sexes [2-4] or by cases of "extraordinary" sex allocation [5]. Deviations from the expected sex ratio are often correlated with weak selection or low environmental predictability (e.g., [6, 7]); true cases of aberrant sex allocation are surprisingly rare [8]. Here, we present a case of long-lasting maladaptive sex allocation, which we discovered in invasive populations of the exclusively sexual brine shrimp Artemia franciscana. A. franciscana was introduced to Southern France roughly 500 generations ago [9]; since then, it has coexisted with the native asexual species Artemia parthenogenetica [10]. Although we expect A. franciscana to produce balanced offspring sex ratios, we regularly observed extremely male-biased sex ratios in invasive A. franciscana, which were significantly correlated to the proportion of asexuals in the overall population. We experimentally proved that both invasive- and native-range A. franciscana overproduced sons when exposed to excess females, without distinguishing between conspecific and asexual females. We conclude that A. franciscana adjust their offspring sex ratio in function of the adult sex ratio but are information limited in the presence of asexual females. Their facultative adjustment trait, which is presumably adaptive in their native range, has thus become maladaptive in the invasive range where asexuals occur. Despite this, it has persisted unchanged for hundreds of generations. PMID:27185556

  8. Oxygen bioavailability and haemoglobins in the brine shrimp Artemia franciscana

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    Wachter, B; Blust, R.; Decleir, W.

    1992-01-01

    Bioavailability of oxygen for the saline-water invertebrate Artemia franciscana was studied, since both oxygen concentration and oxygen diffusion rate change with salinity. Total haemoglobin concentration and the relative contribution of each of three haemoglobins was measured in specimens acclimated to different salinities and oxygen concentrations. Both haemoglobin concentration and contribution were influenced by salinity and the group observed (males, females with and females without eggs...

  9. May arsenic pollution contribute to limiting Artemia franciscana invasion in southern Spain?

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    Sánchez, Marta I; Petit, Cathleen; Martínez-Haro, Mónica; Taggart, Mark A; Green, Andy J

    2016-01-01

    Limited information exists regarding the complex interactions between biological invasions, pollution, and climate change. Most studies indicate that pollution tends to favor invasive species. Here, we provide evidence that arsenic (As) pollution may have a role in limiting the invasion of the exotic brine shrimp Artemia franciscana. We tested As toxicity in natural populations of Artemia parthenogenetica (a native taxon) and A. franciscana from localities in southern Spain with differing degrees of As contamination. Tests were conducted both under current mean temperature conditions (25 °C), and as per a future climate scenario (i.e., an increase in mean temperature of 4 °C). Acute toxicity was estimated on the basis of the median lethal concentration (at 24 h), and chronic toxicity was evaluated by measuring Artemia survival and growth under sublethal exposures (after 26 days). At 25 °C, native A. parthenogenetica from the highly polluted Odiel and Tinto estuary was much more resistant to acute As stress (LC50-24 h, 24.67 mg L(-1)) than A. franciscana (15.78 mg L(-1)) and A. parthenogenetica from unpolluted sites (12.04 mg L(-1))-suggesting that local adaptation to polluted conditions may occur. At 29 °C, resistance of A. parthenogenetica from Odiel decreased significantly, and there were no statistical differences in sensitivity between the three species/populations, suggesting that climate change may enhance the probability of invasion. Resistance increased with developmental stage from nauplii to adults, and was extremely high in cysts which still hatched at As concentrations of up to 6400 mg L(-1). Under sublethal chronic exposure A. franciscana performed better (survival and growth) than A. parthenogenetica, and both species experienced a faster growth when exposed to As, compared with unexposed (control) individuals, probably due to the hormesis. We discuss the ecological implications of our results. PMID:26925327

  10. Intracellular localization of group 3 LEA proteins in embryos of Artemia franciscana.

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    Boswell, Leaf C; Hand, Steven C

    2014-12-01

    Late embryogenesis abundant (LEA) proteins are accumulated by anhydrobiotic organisms in response to desiccation and improve survivorship during water stress. In this study we provide the first direct evidence for the subcellular localizations of AfrLEA2 and AfrLEA3m (and its subforms) in anhydrobiotic embryos of Artemia franciscana. Immunohistochemistry shows AfrLEA2 to reside in the cytoplasm and nucleus, and the four AfrLEA3m proteins to be localized to the mitochondrion. Cellular locations are supported by Western blots of mitochondrial, nuclear and cytoplasmic fractions. The presence of LEA proteins in multiple subcellular compartments of A. franciscana embryos suggests the need to protect biological structures in many areas of a cell in order for an organism to survive desiccation stress, and may explain in part why a multitude of different LEA proteins are expressed by a single organism. PMID:25311474

  11. Impacts of harvesting on brine shrimp (Artemia franciscana) in Great Salt Lake, Utah, USA.

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    Sura, Shayna A; Belovsky, Gary E

    2016-03-01

    Selective harvesting can cause evolutionary responses in populations via shifts in phenotypic characteristics, especially those affecting life history. Brine shrimp (Artemia franciscana) cysts in Great Salt Lake (GSL), Utah, USA are commercially harvested with techniques that select against floating cysts. This selective pressure could cause evolutionary changes over time. Our objectives are to (1) determine if there is a genetic basis to cyst buoyancy, (2) determine if cyst buoyancy and nauplii mortality have changed over time, and (3) to examine GSL environmental conditions over time to distinguish whether selective harvesting pressure or a trend in environmental conditions caused changes in cyst buoyancy and nauplii mortality. Mating crosses between floating and sinking parental phenotypes with two food concentrations (low and high) indicated there is a genetic basis to cyst buoyancy. Using cysts harvested from 1991-2011, we found cyst buoyancy decreased and nauplii mortality increased over time. Data on water temperature, salinity, and chlorophyll a concentration in GSL from 1994 to 2011 indicated that although water temperature has increased over time and chlorophyll a concentration has decreased over time, the selective harvesting pressure against floating cysts is a better predictor of changes in cyst buoyancy and nauplii mortality over time than trends in environmental conditions. Harvesting of GSL A. franciscana cysts is causing evolutionary changes, which has implications for the sustainable management and harvesting of these cysts. Monitoring phenotypic characteristics and life-history traits of the population should be implemented and appropriate responses taken to reduce the impacts of the selective harvesting. PMID:27209783

  12. A gene catalogue for post-diapause development of an anhydrobiotic arthropod Artemia franciscana

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    Yu Jun

    2009-01-01

    Full Text Available Abstract Background Diapause is a reversible state of developmental suspension and found among diverse taxa, from plants to animals, including marsupials and some other mammals. Although previous work has accumulated ample data, the molecular mechanism underlying diapause and reactivation from it remain elusive. Results Using Artemia franciscana, a model organism to study the development of post-diapause embryos in Arthropod, we sequenced random clones up to a total of 28,039 ESTs from four cDNA libraries made from dehydrated cysts and three time points after rehydration/reactivation, which were assembled into 8,018 unigene clusters. We identified 324 differentially-expressed genes (DEGs, P Conclusion We found that the first 5-hour period after rehydration is most important for embryonic reactivation of Artemia. As the total number of expressed genes increases significantly, the majority of DEGs were also identified in this period, including a group of water-deficient-induced genes. A group of genes with similar functions have been described in plant seeds; for instance, one of the novel LEA members shares ~70% amino-acid identity with an Arabidopsis EM (embryonic abundant protein, the closest animal relative to plant LEA families identified thus far. Our findings also suggested that not only nutrition, but also mRNAs are produced and stored during cyst formation to support rapid development after reactivation.

  13. Risk associated with toxic blooms of marine phytoplankton functional groups on Artemia franciscana

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    Ana D’ors

    2014-08-01

    Full Text Available Objective: To study mortality of copepod Artemia franciscana against the occurrence of harmful marine algae and possible toxicological changes exhibited by binary and tertiary combinations of these harmful algae toxins. Methods: Tweenty four hours acute toxicity assays were performed with selected concentrations of Alexandrium minutum, Prorocentrum lima and Nitzschia N1c1 living cells. Additionally, the results were analyzed using the median-effect/combination index (CI-isobologram equation to assess possible changes in the toxic effect induced by phytoplankton functional groups. Results: Biotoxin equivalent values obtained by immunodetection were (2.12±0.10, (8.60±1.30 and (4.32±1.67 pg/cell for saxitoxin, okadaic acid and domoic acid, respectively. The 24-h LC50 values estimated to saxitoxin and okadaic acid equivalents were 4.06 and 6.27 µg/L, significantly below the value obtained for Nitzschia N1c1, which was established at 467.33 µg/L. CI analysis applied on phytoplankton assemblages showed that both ternary mixture as the binary combinations exhibited antagonic action on toxic effects in Artemia nauplii, which were significantly lower than the toxic effect exhibited by each species studied. Conclusions: These results show that, although these harmful algae represent a serious risk to estuarine zooplankton community, the presence of phytoplankton functional groups within the same bloom can reduce the potential risk compared to the expected risk when each of the phytoplankton groups are evaluated individually.

  14. Group 1 LEA proteins contribute to the desiccation and freeze tolerance of Artemia franciscana embryos during diapause.

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    Toxopeus, Jantina; Warner, Alden H; MacRae, Thomas H

    2014-11-01

    Water loss either by desiccation or freezing causes multiple forms of cellular damage. The encysted embryos (cysts) of the crustacean Artemia franciscana have several molecular mechanisms to enable anhydrobiosis-life without water-during diapause. To better understand how cysts survive reduced hydration, group 1 late embryogenesis abundant (LEA) proteins, hydrophilic unstructured proteins that accumulate in the stress-tolerant cysts of A. franciscana, were knocked down using RNA interference (RNAi). Embryos lacking group 1 LEA proteins showed significantly lower survival than control embryos after desiccation and freezing, or freezing alone, demonstrating a role for group 1 LEA proteins in A. franciscana tolerance of low water conditions. In contrast, regardless of group 1 LEA protein presence, cysts responded similarly to hydrogen peroxide (H2O2) exposure, indicating little to no function for these proteins in diapause termination. This is the first in vivo study of group 1 LEA proteins in an animal and it contributes to the fundamental understanding of these proteins. Knowing how LEA proteins protect A. franciscana cysts from desiccation and freezing may have applied significance in aquaculture, where Artemia is an important feed source, and in the cryopreservation of cells for therapeutic applications. PMID:24846336

  15. Risk associated with toxic blooms of marine phytoplankton functional groups on Artemia franciscana

    Institute of Scientific and Technical Information of China (English)

    Ana Dors; Mara Carmen Bartolom; Sebastin Snchez-Fortn

    2014-01-01

    Objective:To study mortality of copepod Artemia franciscana against the occurrence of harmful marine algae and possible toxicological changes exhibited by binary and tertiary combinations of these harmful algae toxins. Methods:Tweenty four hours acute toxicity assays were performed with selected concentrations of Alexandrium minutum, Prorocentrum lima and Nitzschia N1c1 living cells. Additionally, the results were analyzed using the median-effect/combination index (CI)-isobologram equation to assess possible changes in the toxic effect induced by phytoplankton functional groups. Results:Biotoxin equivalent values obtained by immunodetection were (2.12±0.10), (8.60±1.30) and (4.32±1.67) pg/cell for saxitoxin, okadaic acid and domoic acid, respectively. The 24-h LC50 values estimated to saxitoxin and okadaic acid equivalents were 4.06 and 6.27 µg/L, significantly below the value obtained for Nitzschia N1c1, which was established at 467.33 µg/L. CI analysis applied on phytoplankton assemblages showed that both ternary mixture as the binary combinations exhibited antagonic action on toxic effects in Artemia nauplii, which were significantly lower than the toxic effect exhibited by each species studied. Conclusions:These results show that, although these harmful algae represent a serious risk to estuarine zooplankton community, the presence of phytoplankton functional groups within the same bloom can reduce the potential risk compared to the expected risk when each of the phytoplankton groups are evaluated individually.

  16. Does a Change from Whole to Powdered Food (Artemia franciscana eggs Increase Oviposition in the Ladybird Coleomegilla maculata?

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    Eric W. Riddick

    2015-09-01

    Full Text Available The limited availability of alternative foods to replace natural prey hinders cost-effective mass production of ladybird beetles for augmentative biological control. We compared the effects of powdered vs. whole Artemia franciscana (A. franciscana (brine shrimp eggs with or without a dietary supplement on development and reproduction of Coleomegilla maculata (C. maculata (Coleoptera: Coccinellidae. We tested the hypotheses that (1 powdered A. franciscana eggs are more suitable than whole eggs; and (2 palmitic acid, a common fatty acid in natural prey, i.e., aphids, is an effective dietary supplement. Development time, pre-imaginal survival, sex ratio, and body weight of adults did not differ significantly amongst individuals fed powdered vs. whole eggs, with or without 5% palmitic acid. Significantly more oviposition occurred when females were fed powdered eggs than whole eggs and powdered eggs with 5% palmitic acid than whole eggs with or without 5% palmitic acid. A weak functional relationship was found between pre-oviposition time and total oviposition by females fed powdered eggs with 5% palmitic acid; pre-oviposition time decreased as oviposition increased. Food treatments had no significant differential effect on progeny (egg hatch rate. In conclusion, a simple change in A. franciscana egg texture and particle size (i.e., blending whole eggs into a dust-like powder increases oviposition in C. maculata. Supplementing powdered eggs with 5% palmitic acid might accelerate oogenesis (egg maturation in some females.

  17. Effect of low doses of ionizing radiation, azoxystrobin and selected heavy metals on the model organism of species Artemia franciscana

    International Nuclear Information System (INIS)

    The aim of our study was to observe the effect of low doses of ionizing radiation, azoxystrobin, zinc and chrome on the lethality of Artemia franciscana. Significant increase of the lethality was observed after 72 and 96 hours of exposure to azoxystrobin and chrome as well as to azoxystrobin, chrome and irradiation. On the other hand, we observed significant decrease of the lethality in the groups exposed to pesticide and chrome or pesticide and zinc in combination with ionizing radiation with the dose of 50 Gy at time interval of 96 hours in comparison to non-irradiated groups. (authors)

  18. Metabolic restructuring during energy-limited states: insights from Artemia franciscana embryos and other animals.

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    Hand, Steven C; Menze, Michael A; Borcar, Apu; Patil, Yuvraj; Covi, Joseph A; Reynolds, Julie A; Toner, Mehmet

    2011-05-01

    Many life history stages of animals that experience environmental insults enter developmental arrested states that are characterized by reduced cellular proliferation, with or without a concurrent reduction in overall metabolism. In the case of the most profound metabolic arrest reported in invertebrates, i.e., anaerobic quiescence in Artemia franciscana embryos, acidification of the intracellular milieu is a major factor governing catabolic and anabolic downregulation. Release of ions from intracellular compartments is the source for approximately 50% of the proton equivalents needed for the 1.5 unit acidification that is observed. Recovery from the metabolic arrest requires re-sequestration of the protons with a vacuolar-type ATPase (V-ATPase). The remarkable facet of this mechanism is the ability of embryonic cells to survive the dissipation of intracellular ion gradients. Across many diapause-like states, the metabolic reduction and subsequent matching of energy demand is accomplished by shifting energy metabolism from oxidative phosphorylation to aerobic glycolysis. Molecular pathways that are activated to induce these resilient hypometabolic states include stimulation of the AMP-activated protein kinase (AMPK) and insulin signaling via suite of daf (dauer formation) genes for diapause-like states in nematodes and insects. Contributing factors for other metabolically depressed states involve hypoxia-inducible factor-1 and downregulation of the pyruvate dehydrogenase complex. Metabolic similarities between natural states of stasis and some cancer phenotypes are noteworthy. Reduction of flux through oxidative phosphorylation helps prevent cell death in certain cancer types, similar to the way it increases viability of dauer stages in Caenorhabditis elegans. Mechanisms that underlie natural stasis are being used to pre-condition mammalian cells prior to cell biostabilization and storage.

  19. Nano-sized polystyrene affects feeding, behavior and physiology of brine shrimp Artemia franciscana larvae.

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    Bergami, Elisa; Bocci, Elena; Vannuccini, Maria Luisa; Monopoli, Marco; Salvati, Anna; Dawson, Kenneth A; Corsi, Ilaria

    2016-01-01

    Nano-sized polymers as polystyrene (PS) constitute one of the main challenges for marine ecosystems, since they can distribute along the whole water column affecting planktonic species and consequently disrupting the energy flow of marine ecosystems. Nowadays very little knowledge is available on the impact of nano-sized plastics on marine organisms. Therefore, the present study aims to evaluate the effects of 40nm anionic carboxylated (PS-COOH) and 50nm cationic amino (PS-NH2) polystyrene nanoparticles (PS NPs) on brine shrimp Artemia franciscana larvae. No signs of mortality were observed at 48h of exposure for both PS NPs at naplius stage but several sub-lethal effects were evident. PS-COOH (5-100μg/ml) resulted massively sequestered inside the gut lumen of larvae (48h) probably limiting food intake. Some of them were lately excreted as fecal pellets but not a full release was observed. Likewise, PS-NH2 (5-100µg/ml) accumulated in larvae (48h) but also adsorbed at the surface of sensorial antennules and appendages probably hampering larvae motility. In addition, larvae exposed to PS-NH2 undergo multiple molting events during 48h of exposure compared to controls. The activation of a defense mechanism based on a physiological process able to release toxic cationic NPs (PS-NH2) from the body can be hypothesized. The general observed accumulation of PS NPs within the gut during the 48h of exposure indicates a continuous bioavailability of nano-sized PS for planktonic species as well as a potential transfer along the trophic web. Therefore, nano-sized PS might be able to impair food uptake (feeding), behavior (motility) and physiology (multiple molting) of brine shrimp larvae with consequences not only at organism and population level but on the overall ecosystem based on the key role of zooplankton on marine food webs. PMID:26422775

  20. Liposomes with diverse compositions are protected during desiccation by LEA proteins from Artemia franciscana and trehalose.

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    Moore, Daniel S; Hansen, Richard; Hand, Steven C

    2016-01-01

    Intracellular accumulation of Late Embryogenesis Abundant (LEA) proteins and the disaccharide trehalose is associated with cellular desiccation tolerance in a number of animal species. Two LEA proteins from anhydrobiotic embryos of the brine shrimp Artemia franciscana were tested for the ability to protect liposomes of various compositions against desiccation-induced damage in the presence and absence of trehalose. Damage was assessed by carboxyfluorescein leakage after drying and rehydration. Further, using a cytoplasmic-localized (AfrLEA2) and a mitochondrial-targeted (AfrLEA3m) LEA protein allowed us to evaluate whether each may preferentially stabilize membranes of a particular lipid composition based on the protein's subcellular location. Both LEA proteins were able to offset damage during drying of liposomes that mimicked the lipid compositions of the inner mitochondrial membrane (with cardiolipin), outer mitochondrial membrane, and the inner leaflet of the plasma membrane. Thus liposome stabilization by AfrLEA3m or AfrLEA2 was not dependent on lipid composition, provided physiological amounts of bilayer and non-bilayer-forming lipids were present (liposomes with a non-biological composition of 100% phosphatidylcholine were not protected by either protein). Additive protection by LEA proteins plus trehalose was dependent on the lipid composition of the target membrane. Minimal additional damage occurred to liposomes stored at room temperature in the dried state for one week compared to liposomes rehydrated after 24h. Consistent with the ability to stabilize lipid bilayers, molecular modeling of the secondary structures for AfrLEA2 and AfrLEA3m revealed bands of charged amino acids similar to other amphipathic proteins that interact directly with membranes. PMID:26518519

  1. Recreating the seawater mixture composition of HOCs in toxicity tests with Artemia franciscana by passive dosing

    International Nuclear Information System (INIS)

    The toxicity testing of hydrophobic organic compounds (HOCs) in aquatic media is generally challenging, and this is even more problematic for mixtures. The hydrophobic properties of these compounds make them difficult to dissolve, and subsequently to maintain constant exposure concentrations. Evaporative and sorptive losses are highly compound-specific, which can alter not only total concentrations, but also the proportions between the compounds in the mixture. Therefore, the general aim of this study was to explore the potential of passive dosing for testing the toxicity of a PAH mixture that recreates the mixture composition found in seawater from a coastal area of Spain, the Bay of Algeciras. First, solvent spiking and passive dosing were compared for their suitability to determine the acute toxicity to Artemia franciscana nauplii of several PAHs at their respective solubility limits. Second, passive dosing was applied to recreate the seawater mixture composition of PAHs measured in a Spanish monitoring program, to test the toxicity of this mixture at different levels. HPLC analysis was used to confirm the reproducibility of the dissolved exposure concentrations for the individual PAHs and mixtures. This study shows that passive dosing has some important benefits in comparison with solvent spiking for testing HOCs in aquatic media. These include maintaining constant exposure concentrations, leading to higher reproducibility and a relative increase in toxicity. Passive dosing is also able to faithfully reproduce real mixtures of HOCs such as PAHs, in toxicity tests, reproducing both the levels and proportions of the different compounds. This provides a useful approach for studying the toxicity of environmental mixtures of HOCs, both with a view to investigating their toxicity but also for determining safety factors before such mixtures result in detrimental effects.

  2. Bird migratory flyways influence the phylogeography of the invasive brine shrimp Artemia franciscana in its native American range

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    Joaquín Muñoz

    2013-11-01

    Full Text Available Since Darwin’s time, waterbirds have been considered an important vector for the dispersal of continental aquatic invertebrates. Bird movements have facilitated the worldwide invasion of the American brine shrimp Artemia franciscana, transporting cysts (diapausing eggs, and favouring rapid range expansions from introduction sites. Here we address the impact of bird migratory flyways on the population genetic structure and phylogeography of A. franciscana in its native range in the Americas. We examined sequence variation for two mitochondrial gene fragments (COI and 16S for a subset of the data in a large set of population samples representing the entire native range of A. franciscana. Furthermore, we performed Mantel tests and redundancy analyses (RDA to test the role of flyways, geography and human introductions on the phylogeography and population genetic structure at a continental scale. A. franciscana mitochondrial DNA was very diverse, with two main clades, largely corresponding to Pacific and Atlantic populations, mirroring American bird flyways. There was a high degree of regional endemism, with populations subdivided into at least 12 divergent, geographically restricted and largely allopatric mitochondrial lineages, and high levels of population structure (ΦST of 0.92, indicating low ongoing gene flow. We found evidence of human-mediated introductions in nine out of 39 populations analysed. Once these populations were removed, Mantel tests revealed a strong association between genetic variation and geographic distance (i.e., isolation-by-distance pattern. RDA showed that shared bird flyways explained around 20% of the variance in genetic distance between populations and this was highly significant, once geographic distance was controlled for. The variance explained increased to 30% when the factor human introduction was included in the model. Our findings suggest that bird-mediated transport of brine shrimp propagules does not result

  3. Quiescence in Artemia franciscana embryos: reversible arrest of metabolism and gene expression at low oxygen levels.

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    Hand, S C

    1998-04-01

    Depression of the production and consumption of cellular energy appears to be a prerequisite for the survival of prolonged bouts of anoxia. A correlation exists between the degree of metabolic depression under anoxia and the duration of anoxia tolerance. In the case of brine shrimp (Artemia franciscana) embryos, oxygen deprivation induces a reversible quiescent state that can be tolerated for several years with substantial survivorship. A global arrest of cytoplasmic translation accompanies the transition into anoxia, and rates of protein synthesis in mitochondria from these embryos appears to be markedly reduced in response to anoxia. Previous evidence suggests that the acute acidification of intracellular pH (pHi) by over 1.0 unit during the transition into anoxia contributes to the depression of biosynthesis, but message limitation does not appear to play a role in the down-regulation in either cellular compartment. The ontogenetic increase in mRNA levels for a mitochondrial-encoded subunit of cytochrome c oxidase (COX I) and for nuclear-encoded actin is blocked by anoxia and aerobic acidosis (artificial quiescence imposed by intracellular acidification under aerobic conditions). Further, the levels of COX I and actin mRNA do not decline appreciably during 6 h bouts of quiescence, even though protein synthesis is acutely arrested across this same period. Thus, the constancy of mRNA levels during quiescence indicates that reduced protein synthesis is not caused by message limitation but, instead, is probably controlled at the translational level. This apparent stabilization of mRNA under anoxia is mirrored in an extension of protein half-life. The ubiquitin-dependent pathway for protein degradation is depressed under anoxia and aerobic acidosis, as judged by the acute drop in levels of ubiquitin-conjugated proteins. Mitochondrial protein synthesis is responsive to both acidification of pHi and removal of oxygen per se. Matrix pH declines in parallel with pHi, and

  4. Parasitismo por cestodos en Artemia spp. y su implicación en la invasión biológica de Artemia franciscana en la región Mediterránea

    OpenAIRE

    Redón Calvillo, Stella

    2015-01-01

    La presente Tesis Doctoral trata del fenómeno del parasitismo en el crustáceo Artemia y la implicación de los cestodos en el proceso de invasión biológica de la especie americana Artemia franciscana Kellogg, 1906 en la región Mediterránea. El crustáceo Artemia (Branchiopoda, Anostraca) es el invertebrado más conspicuo de los ecosistemas acuáticos hipersalinos de todo el mundo y un valioso recurso trófico para las poblaciones de aves acuáticas que residen en dichos ecosistemas. El uso generali...

  5. Depression of nuclear transcription and extension of mRNA half-life under anoxia in Artemia franciscana embryos.

    Science.gov (United States)

    van Breukelen, F; Maier, R; Hand, S C

    2000-04-01

    Transcriptional activity, as assessed by nuclear run-on assays, was constant during 10 h of normoxic development for embryos of the brine shrimp Artemia franciscana. Exposure of embryos to only 4 h of anoxia resulted in a 79.3+/-1 % decrease in levels of in-vivo-initiated transcripts, and transcription was depressed by 88. 2+/-0.7 % compared with normoxic controls after 24 h of anoxia (means +/- s.e.m., N=3). Initiation of transcription was fully restored after 1 h of normoxic recovery. Artificially lowering the intracellular pH of aerobic embryos to the value reflective of anoxia (pH 6.7) showed that acidification alone explained over half the transcriptional arrest. Initiation of transcription was not rescued by application of 80 % carbon monoxide under anoxia, which suggests that heme-based oxygen sensing is not involved in this global arrest. When these transcriptional data are combined with the finding that mRNA levels are unchanged for at least 6 h of anoxia, it is clear that the half-life of mRNA is extended at least 8.5-fold compared with that in aerobic embryos. In contrast to the activation of compensatory mechanisms to cope with anoxia that occurs in mammalian cells, A. franciscana embryos enter a metabolically depressed state in which gene expression and mRNA turnover are cellular costs apparently not compatible with survival and in which extended tolerance supercedes the requirement for continued metabolic function. PMID:10708633

  6. The effects of dietary administration with chemical treated Saccharomyces cerevisiae strain YG3-1 on the growth of aquatic invertebrates in Artemia

    Directory of Open Access Journals (Sweden)

    Behnam Shekarchi

    2016-02-01

    Full Text Available Objective: To investigate the biological effects of β-glucans in cell wall of new identified strain Saccharomyces cerevisiae strain YG3-1 on the growth of aquatic invertebrates, in Artemia as model organism. Methods: All yeasts used in the present study were isolated from Rainbow trout intestine and then cultured in yeast extract-peptone-glycerol medium. Activation of β-glucan in yeasts was performed by chemical treatment with 2-mercaptoethanol (2ME (3.5% v/v. Then nauplii and larvae individuals of Artemia urmiana and Artemia franciscana (two different species of Artemia as test organisms were fed with 2ME-treated yeasts during the culture. At the end of experiment, after feeding individual length (total length and growth rate in adult individuals of Artemia was measured. Results: Following this administration, growth in both species of Artemia was improved (P < 0.05. So, the results showed that Artemia urmiana adults individuals that fed with 2MEtreated yeasts had the highest growth and total length. These results were confirmed with growth measurement in adult individuals of Artemia. Conclusions: This study suggested that 2ME-treated Saccharomyces cerevisiae strain YG3-1 yeasts can be used for enhancing the growth of other aquatic invertebrates like shrimps as probiotic supplement and growth promoter.

  7. Group 3 late embryogenesis abundant proteins from embryos of Artemia franciscana: structural properties and protective abilities during desiccation.

    Science.gov (United States)

    Boswell, Leaf C; Menze, Michael A; Hand, Steven C

    2014-01-01

    Group 3 late embryogenesis abundant (LEA) proteins are highly hydrophilic, and their expression is associated with desiccation tolerance in both plants and animals. Here we show that two LEA proteins from embryos of Artemia franciscana, AfrLEA2 and AfrLEA3m, are intrinsically disordered in solution but upon desiccation gain secondary structure, as measured by circular dichroism. Trifluoroethanol and sodium dodecyl sulfate are both shown to induce α-helical structure in AfrLEA2 and AfrLEA3m. Bioinformatic predictions of secondary-structure content for both proteins correspond most closely to conformations measured in the dry state. Because some LEA proteins afford protection to desiccation-sensitive proteins during drying and subsequent rehydration, we tested for this capacity in AfrLEA2 and AfrLEA3m. The protective capacities vary, depending on the target enzyme. For the cytoplasmic enzyme lactate dehydrogenase, neither AfrLEA2 nor AfrLEA3m, with or without trehalose present, was able to afford protection better than that provided by bovine serum albumin (BSA) under the same conditions. However, for another cytoplasmic enzyme, phosphofructokinase, both AfrLEA2 and AfrLEA3m in the presence of trehalose were able to afford protection far greater than that provided by BSA with trehalose. Finally, for the mitochondrial enzyme citrate synthase, 400-μg/mL AfrLEA3m without trehalose provided significantly more protection than the same concentration of either AfrLEA2 or BSA. PMID:25244376

  8. Profiles of nuclear and mitochondrial encoded mRNAs in developing and quiescent embryos of Artemia franciscana.

    Science.gov (United States)

    Hardewig, I; Anchordoguy, T J; Crawford, D L; Hand, S C

    1996-05-24

    Embryos of the brine shrimp Artemia franciscana are able to withstand long bouts of environmental anoxia by entering a quiescent state during which metabolism is greatly depressed. Recent evidence supports a global arrest of protein synthesis during quiescence. In this study we measured the amounts of mRNA for a mitochondrial-encoded subunit of cytochrome c oxidase (COX I) and for nuclear-encoded actin during aerobic development, anaerobiosis, and aerobic acidosis (artificial quiescence imposed by intracellular acidification under aerobic conditions). The levels of both COX I and actin transcripts increased significantly during aerobic development. COX I mRNA levels were tightly correlated with previous measures of COX catalytic activity, which suggests that COX synthesis could be regulated by message concentration during aerobic development. The ontogenetic increase for these mRNAs was blocked by anoxia and aerobic acidosis. Importantly, the levels of COX I and actin mRNA did not decline appreciably during the 6 h bouts of quiescence, even though protein synthesis is acutely arrested by these same treatments. Thus, the constancy of mRNA levels during quiescence indicate that reduced protein synthesis is not caused by message limitation, but rather, is likely controlled at the translational level. One advantage of this regulatory mechanism is the conservation of mRNA molecules during quiescence, which would potentially favor a quick resumption of translation as soon as oxygen is returned to the embryos. Finally, because anoxia and aerobic acidosis are both characterized by acidic intracellular pH, the reduction in pH may serve, directly or indirectly, as one signal regulating levels of mRNA in this embryo during quiescence. PMID:8817476

  9. The effects of dietary administration with chemical treated Saccharomyces cerevisiae strain YG3-1 on the growth of aquatic invertebrates in Artemia

    Institute of Scientific and Technical Information of China (English)

    Behnam Shekarchi; Ali Nekuiefard; Ramin Manaffar

    2016-01-01

    Objective: To investigate the biological effects of β-glucans in cell wall of new identified strain Saccharomyces cerevisiae strain YG3-1 on the growth of aquatic invertebrates, in Artemia as model organism. Methods: All yeasts used in the present study were isolated from Rainbow trout intestine and then cultured in yeast extract-peptone-glycerol medium. Activation of β-glucan in yeasts was performed by chemical treatment with 2-mercaptoethanol (2ME) (3.5% v/v). Then nauplii and larvae individuals of Artemia urmiana and Artemia franciscana (two different species of Artemia as test organisms) were fed with 2ME-treated yeasts during the culture. At the end of experiment, after feeding individual length (total length and growth rate) in adult individuals of Artemia was measured. Results: Following this administration, growth in both species of Artemia was improved (P Conclusions: This study suggested that 2ME-treated Saccharomyces cerevisiae strain YG3-1 yeasts can be used for enhancing the growth of other aquatic invertebrates like shrimps as probiotic supplement and growth promoter.

  10. A case study to optimise and validate the brine shrimp Artemia franciscana immobilisation assay with silver nanoparticles: The role of harmonisation.

    Science.gov (United States)

    Kos, Monika; Kahru, Anne; Drobne, Damjana; Singh, Shashi; Kalčíková, Gabriela; Kühnel, Dana; Rohit, Rekulapelly; Gotvajn, Andreja Žgajnar; Jemec, Anita

    2016-06-01

    Brine shrimp Artemia sp. has been recognised as an important ecotoxicity and nanotoxicity test model organism for salt-rich aquatic environments, but currently there is still no harmonised testing protocol which would ensure the comparable results for hazard identification. In this paper we aimed to design the harmonised protocol for nanomaterial toxicity testing using Artemia franciscana and present a case study to validate the protocol with silver nanoparticles (AgNPs). We (i) revised the existing nanotoxicity test protocols with Artemia sp. (ii) optimised certain methodological steps based on the experiments with AgNPs and potassium dichromate (K2Cr2O7) as a soluble reference chemical and (iii) tested the optimised protocol in an international inter-laboratory exercise conducted within the EU FP7 NanoValid project. The intra- and inter-laboratory reproducibility of the proposed protocol with a soluble reference chemical K2Cr2O7 was good, which confirms the suitability of this assay for conventional chemicals. However, the variability of AgNPs toxicity results was very high showing again that nanomaterials are inherently challenging for toxicity studies, especially those which toxic effect is linked to shed metal ions. Among the identified sources for this variability were: the hatching conditions, the type of test plate incubation and the illumination regime. The latter induced variations assumingly due to the changes in bioavailable silver species concentrations. Up to our knowledge this is the first inter-laboratory comparison of the Artemia sp. toxicity study involving nanomaterials. Although the inter-laboratory exercise revealed poor repeatability of AgNPs toxicity results, this study provides valuable information regarding the importance of harmonisation of all steps in the test procedure. Also, the presented AgNPs toxicity case study may serve as a platform for further validation steps with other types of NMs. PMID:26895539

  11. Determinación de la toxicidad aguda (cl50) del extracto de polvillo de carbón frente a larvas de artemia franciscana

    OpenAIRE

    Pacheco Gómez, Jesús David

    2011-01-01

    El carbón es una de las fuentes de energía más utilizada, su uso es globalizado y está muy ligado con el desarrollo industrial, sin embargo, es considerado como el contaminante de fuente de energía fósil más importante del mundo y su explotación está relacionada con la aparición de efectos tóxicos en diferentes organismos. El presente estudio tuvo por objetivo determinar la concentración letal media (CL50) del extracto metanólico de polvillo de carbón frente a larvas de Artemia franciscana; l...

  12. Field culture of American strain of Artemia in India

    Digital Repository Service at National Institute of Oceanography (India)

    Royan, J.P.; Sumitra-Vijayaraghavan; Krishnakumari, L.

    Pilot scale culture of Artemia was carried out in a 0.22 ha condenser unit of salt pans. Pond was fertilized with inorganic salts. The nauplii of San Francisco Bay, USA strain were inoculated. Within a period of 5 months a production of 20.6 kg dry...

  13. Non-lethal heat shock protects gnotobiotic Artemia franciscana larvae against virulent Vibrios

    OpenAIRE

    Yik Sung, Y.; Van Damme, E.J.M.; Sorgeloos, P.; Bossier, P

    2007-01-01

    Brine shrimp Artemia were exposed under gnotobiotic conditions to a non-lethal heat shock (NLHS) from 28 to 32, 37 and 40°C. Different recovery periods (2, 6, 12 and 24 h) and different heat-exposure times (15, 30, 45 and 60 min) were tested. After these NLHS, Artemia was subsequently challenged with Vibrio. Challenge tests were performed in stressed and unstressed nauplii at concentrations of 107 cells ml-1 of pathogenic bacteria, Vibrio campbellii and Vibrio proteolyticus. A NLHS with an op...

  14. Bacillus sp. LT3 improves the survival of gnotobiotic brine shrimp (Artemia franciscana) larvae challenged with Vibrio campbellii by enhancing the innate immune response and by decreasing the activity of shrimp-associated vibrios.

    Science.gov (United States)

    Niu, Yufeng; Defoirdt, Tom; Baruah, Kartik; Van de Wiele, Tom; Dong, Shuanglin; Bossier, Peter

    2014-10-10

    Bacteria belonging to the genus Bacillus are amongst the most intensively studied group of bacteria for use as probiotics in aquaculture. However, the exact mechanism of action of these bacteria is often not well described, and the microbiota that are naturally present in cultures of test organisms often compromise the interpretation of the results. The present study aimed to evaluate the putative probiotic effect of Bacillus sp. LT3 in a model system with gnotobiotic brine shrimp Artemia franciscana larvae. The strain significantly increased the survival of brine shrimp larvae challenged with Vibrio campbellii when administered 6h before the challenge. Under these conditions, LT3 was able to colonize the brine shrimp gastrointestinal tract and to decrease the in vivo pathogen activity as indicated by the bioluminescence of the V. campbellii associated with brine shrimp larvae. In order to investigate the effect of the Bacillus strain on the innate immune system of the brine shrimp larvae, prophenoloxidase and transglutaminase mRNA levels were monitored, while heat shock protein 70 mRNA levels were measured as an indicator of physiological stress. Interestingly, 12h after challenge, the prophenoloxidase mRNA level in the larvae pre-treated with LT3 and challenged with V. campbellii was approximately 8-fold higher than in the other treatments. Further, a decreased mRNA level of transglutaminase gene and heat shock protein 70 gene suggested that pretreatment with LT3 results in less stress and tissue damage in the brine shrimp larvae upon V. campbellii challenge. These results indicated that Bacillus sp. LT3 could improve the survival of brine shrimp larvae when challenged with pathogenic V. campbellii, both by decreasing the in vivo activity of the pathogen and by priming the innate immune response through activating the prophenoloxidase system.

  15. Trophic transfer of lead through a model marine four-level food chain: Tetraselmis suecica, Artemia franciscana, Litopenaeus vannamei, and Haemulon scudderi.

    Science.gov (United States)

    Soto-Jiménez, M F; Arellano-Fiore, C; Rocha-Velarde, R; Jara-Marini, M E; Ruelas-Inzunza, J; Páez-Osuna, F

    2011-08-01

    The objective of this investigation was to assess the transfer of lead (Pb) along an experimental, four-level food chain: Tetraselmis suecica (phytoplankton) → Artemia franciscana (crustacean, brine shrimp) → Litopenaeus vannamei (crustacean, white shrimp) → Haemulon scudderi (fish, grunt). T. suecica was exposed to a sublethal dose of Pb in solution and then used as the base of a marine food chain. Significant differences in Pb concentrations were found between exposed organisms of the different trophic levels and the control. Particularly, Pb concentrations in fish of the simulated trophic chain were two-to three times higher in the exposed specimens than in the control. Levels of Pb in phytoplankton showed a substantial increase with respect to the solution (level I), with bioconcentration factors averaging from 930 to 3630. In contrast, a strong decrease in Pb concentration from phytoplankton to zooplankton (level II) and from zooplankton to shrimp tissues (level III) was evidenced by bioaccumulation factors metal transfer observed in these two predators, Pb concentration in the grunt fish (level IV) was higher than in the shrimp (level III) (bioaccumulation factor >1.0). Some of the added Pb is transferred from the phytoplankton along the food chain, thus producing a net accumulation of Pb mainly in fish and, to a lesser extent, in shrimp tissues. Because Pb is one of the most pervasive contaminants in coastal ecosystems, its transference by way of diet and potential net accumulation in higher predators is of ecologic importance for marine life. In addition, because shrimp and adult Haemulon scudderi are commercially important resources, this issue is of particular relevance to the safety of marine products. PMID:21082317

  16. The gnotobiotic brine shrimp (Artemia franciscana) model system reveals that the phenolic compound pyrogallol protects against infection through its prooxidant activity.

    Science.gov (United States)

    Baruah, Kartik; Duy Phong, Ho Phuong Pham; Norouzitallab, Parisa; Defoirdt, Tom; Bossier, Peter

    2015-12-01

    The phenolic compound pyrogallol is the functional unit of many polyphenols and currently there has been a growing interest in using this compound in human and animal health owing to its health-promoting effects. The biological actions of pyrogallol moiety (and polyphenols) in inducing health benefitting effects have been studied; however, the mechanisms of action remain unclear yet. Here, we aimed at unravelling the underlying mechanism of action behind the protective effects of pyrogallol against bacterial infection by using the gnotobiotically-cultured brine shrimp Artemia franciscana and pathogenic bacteria Vibrio harveyi as host-pathogen model system. The gnotobiotic test system represents an exceptional system for carrying out such studies because it eliminates any possible interference of microbial communities (naturally present in the experimental system) in mechanistic studies and furthermore facilitates the interpretation of the results in terms of a cause effect relationship. We provided clear evidences suggesting that pyrogallol pretreament, at an optimum concentration, induced protective effects in the brine shrimp against V. harveyi infection. By pretreating brine shrimp with pyrogallol in the presence or absence of an antioxidant enzyme mixture (catalase and superoxide dismutase), we showed that the Vibrio-protective effect of the compound was caused by its prooxidant action (e.g. generation of hydrogen peroxide, H2O2). We showed further that generation of prooxidant is linked to the induction of heat shock protein Hsp70, which is involved in eliciting the prophenoloxidase and transglutaminase immune responses. The ability of pyrogallol to induce protective immunity makes it a potential natural protective agent that might be a potential preventive modality for different host-pathogen systems. PMID:26459033

  17. Co-feeding of microalgae and bacteria may result in increased N assimilation in Artemia as compared to mono-diets, as demonstrated by a 15N isotope uptake laboratory study

    OpenAIRE

    Toi, H.T.; Boeckx, P.; Sorgeloos, P.; Bossier, P.; Van Stappen, G.

    2014-01-01

    This study investigated the effect of the co-feeding of bacteria and microalgae on nitrogen (N) assimilation in an Artemia franciscana gnotobiotic laboratory culture test. Two strains of bacteria were used, HT3 and HT6, isolated from previous Artemia laboratory cultures. These were fed in combination with microalga Dunaliella tertiolecta strains, either the high quality DT 19/6B or the low quality DT 19/27 strain. Each combination of algae and bacteria was offered in different proportions, i....

  18. Reactive oxygen species generated by a heat shock protein (Hsp) inducing product contributes to Hsp70 production and Hsp70-mediated protective immunity in Artemia franciscana against pathogenic vibrios.

    Science.gov (United States)

    Baruah, Kartik; Norouzitallab, Parisa; Linayati, Linayati; Sorgeloos, Patrick; Bossier, Peter

    2014-10-01

    The cytoprotective role of heat shock protein (Hsp70) described in a variety of animal disease models, including vibriosis in farmed aquatic animals, suggests that new protective strategies relying upon the use of compounds that selectively turn on Hsp genes could be developed. The product Tex-OE® (hereafter referred to as Hspi), an extract from the skin of the prickly pear fruit, Opuntia ficus indica, was previously shown to trigger Hsp70 synthesis in a non-stressful situation in a variety of animals, including in a gnotobiotically (germ-free) cultured brine shrimp Artemia franciscana model system. This model system offers great potential for carrying out high-throughput, live-animal screens of compounds that have health benefit effects. By using this model system, we aimed to disclose the underlying cause behind the induction of Hsp70 by Hspi in the shrimp host, and to determine whether the product affects the shrimp in inducing resistance towards pathogenic vibrios. We provide unequivocal evidences indicating that during the pretreatment period with Hspi, there is an initial release of reactive oxygen species (hydrogen peroxide and/or superoxide anion), generated by the added product, in the rearing water and associated with the host. The reactive molecules generated are the triggering factors responsible for causing Hsp70 induction within Artemia. We have also shown that Hspi acts prophylactically at an optimum dose regimen to confer protection against pathogenic vibrios. This salutary effect was associated with upregulation of two important immune genes, prophenoloxidase and transglutaminase of the innate immune system. These findings suggest that inducers of stress protein (e.g. Hsp70) are potentially important modulator of immune responses and might be exploited to confer protection to cultured shrimp against Vibrio infection. PMID:24950414

  19. UTILIZAÇÃO DA CIANOBACTÉRIA Spirulina maxima E DA LEVEDURA Saccharomyces cerevisiae COMO DIETAS COMPLEMENTARES NO CULTIVO DE Artemia franciscana

    OpenAIRE

    Ivanildo Surini de Souza; Pedro Hercílio Cavalcante de Oliveira

    2015-01-01

    Diferentes combinações da cianobactéria S. maxima e da levedura S. cerevisiae foram utilizadas no cultivo de A. franciscana, com o objetivo de avaliar dietas de baixo custo e fácil manuseio, e que mantivessem as larvas desse microcrustáceo em laboratório, de modo a propiciar estudos de sua ecologia, biologia e uso na aquicultura. Para isso, 12 cones de Imhoff contendo 1 L de água do mar filtrada foram estocados com 100 náuplios e submetidos à aeração contínua, monitoramento do pH, temperatura...

  20. UTILIZAÇÃO DA CIANOBACTÉRIA Spirulina maxima E DA LEVEDURA Saccharomyces cerevisiae COMO DIETAS COMPLEMENTARES NO CULTIVO DE Artemia franciscana

    Directory of Open Access Journals (Sweden)

    Ivanildo Surini de Souza

    2015-07-01

    Full Text Available Diferentes combinações da cianobactéria S. maxima e da levedura S. cerevisiae foram utilizadas no cultivo de A. franciscana, com o objetivo de avaliar dietas de baixo custo e fácil manuseio, e que mantivessem as larvas desse microcrustáceo em laboratório, de modo a propiciar estudos de sua ecologia, biologia e uso na aquicultura. Para isso, 12 cones de Imhoff contendo 1 L de água do mar filtrada foram estocados com 100 náuplios e submetidos à aeração contínua, monitoramento do pH, temperatura, salinidade, oxigênio dissolvido e luminosidade, além de renovação diária de 50 % do volume de água. Durante dez dias, os náuplios foram alimentados duas vezes ao dia com 25 mg de diferentes combinações de S. maxima e S. cerevisiae, nas seguintes proporções: 100/0; 75/25; 50/50; 25/75 e 0/100. Foram avaliadas a taxa de sobrevivência, proporção sexual, proporção juvenis/adultos e performance reprodutiva. Os resultados indicaram um melhor desempenho zootécnico de A. franciscana nos tratamentos que associaram S. maxima à S. cerevisiae (75/25, 50/50 e 25/75, e desta maneira, demonstram que a referida mistura dietética, em tais proporções, é viável para manter as larvas em cultivo laboratorial.

  1. Physical, biochemical and functional characterization of haemoglobin from three strains of Artemia.

    Science.gov (United States)

    Sugumar, Vasudevan; Munuswamy, Natesan

    2007-02-01

    The brine shrimp, Artemia, an inhabitant of coastal and inland salterns, encounter fluctuations in the salinity which in turn influences the oxygen availability of their habitat. Hence, experiments were performed to analyze variations in haemoglobin structure and patterns of three strains of Artemia from South India and also to reflect the effect of varying oxygen levels in their habitat. Haemoglobins were purified on a DEAE-Sephadex column and haemoglobin types were analyzed by comparing their relative mobility on a non-denaturing medium. Furthermore, their molecular masses were determined by gel filtration in Sepharose column and by dodecylsulfate polyacrylamide gel electrophoresis. Results clearly reveal the presence of three distinct extracellular haemoglobins Hb I, Hb II and Hb III in Tuticorin strain while the other strains displayed only trails or the complete absence of Hb III and Hb II. Estimated molecular masses of these haemoglobins are 235,000-250,000 Da. Denaturation of the reduced and alkylated haemoglobins revealed apparently one polypeptide chain with a molecular mass of 124,000 Da. Upon denaturing gel electrophoresis of native haemoglobin Hb II, it was found that the 124,000 Da, polypeptide was cleaved specifically into two unequally-sized fragments of 50,400 and 79,800 Da. With regard to oxygen affinity, Hb III has a very high affinity for oxygen, an almost negligible Bohr effect and a good physiological adaptation to temperature changes. By combining the three haemoglobins in different proportions Artemia strains must be able to withstand diverging environmental conditions. In particular, the absence of Hb III in Puthalam and its occurrence as a faint band in Thamaraikulam could be correlated to the oxygen levels of their habitats. PMID:17185017

  2. Comparación biométrica del lóbulo frontal en poblaciones americanas de Artemia (Anostraca, Artemiidae Biometric comparision of the frontal knob in american populations of Artemia (Anostraca, Artemiidae

    Directory of Open Access Journals (Sweden)

    PATRICIO R DE LOS RIOS

    2000-03-01

    Full Text Available Se compararon el diámetro del lóbulo frontal y su relación con la longitud corporal, en poblaciones de Artemia franciscana (Chile y Estados Unidos, A. persimilis (Argentina y Artemia sp. (Chile, cultivadas en laboratorio bajo condiciones controladas. Se encontraron diferencias significativas en ambos parámetros entre las poblaciones de A. franciscana y Artemia sp., de Salina El Convento (Chile y entre A. persimilis y Artemia sp. de Torres del Paine (Chile. Se discuten en el presente trabajo los factores geográficos, ecológicos y genéticos que determinaron la especiación de Artemia en Chile y Argentina, y como ésta se manifiesta en distintos patrones morfométricosThe frontal knob diameter and its relationship with the total body lenght among populations of Artemia franciscana (Chile and U.S.A, A. persimilis (Argentina, and Artemia sp. (Chile, were asessed. All populations were cultured under laboratory conditions. Significant differences in both parameters between A. franciscana and Artemia sp. from Salina el Convento (Chile, and between A. persimilis and Artemia sp. from Amarga Lagoon (Chile were recorded.Geographical, ecological and genetic aspects which affected the speciation of Artemia populations in Chile and Argentina, and their expression in morphometric characters are discussed

  3. Characterization of polymorphic microsatellite markers in the brine shrimp Artemia (Branchiopoda, Anostraca)

    DEFF Research Database (Denmark)

    Muñoz, Joaquin; Green, Andy J.; Figuerola, Jordi;

    2009-01-01

    The brine shrimp Artemia is a complex genus containing sexual species and parthenogenetic lineages. Artemia franciscana is native to America and its cysts (diapausing eggs) are used worldwide as a food source in aquaculture. As a consequence, this anostracan has become an invasive species in many...

  4. Genetic characterization of Artemia tibetiana (Crustacea: Anostraca)

    OpenAIRE

    Abatzopoulos, T.J.; Kappas, I.; Bossier, P.; Sorgeloos, P.; Beardmore, J. A.

    2002-01-01

    The brine shrimp Artemia consists of a number of bisexual species and a large number of parthenogenetic forms, which collectively, inhabit a wide range of hypersaline habitats. A recently described species (A. tibetiana) from a carbonate lake (Lagkor Co) in Tibet at an altitude of 4490 m has been tested with New World (A. franciscana USA, and A. franciscana feral population Vietnam) and Old World species (A. salina, A. urmiana, A. sinica) for cross fertility. These tests show complete inferti...

  5. Aquatic pollution may favor the success of the invasive species A. franciscana

    Energy Technology Data Exchange (ETDEWEB)

    Varó, I., E-mail: inma@iats.csic.es [Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Ribera de Cabanes, Castellón 12595 Spain (Spain); Redón, S. [Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Ribera de Cabanes, Castellón 12595 Spain (Spain); Garcia-Roger, E.M. [Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, Burjassot (Spain); Amat, F.; Guinot, D. [Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Ribera de Cabanes, Castellón 12595 Spain (Spain); Serrano, R. [Research Institute for Pesticides and Water (IUPA), Avda. Sos Baynat, s/n. University Jaume I, Castellón 12071 (Spain); Navarro, J.C. [Instituto de Acuicultura Torre de la Sal (IATS-CSIC), Ribera de Cabanes, Castellón 12595 Spain (Spain)

    2015-04-15

    Highlights: • Artemia species display an elevated tolerance to high ranges of chlorpyrifos. • A. franciscana survived better and its fecundity was less affected by chlorpyrifos. • The higher fecundity of A. franciscana is a selective advantage in colonization processes. • Higher survival and biological fitness in A. franciscana indicate out-competitive advantages. - Abstract: The genus Artemia consists of several bisexual and parthenogenetic sibling species. One of them, A. franciscana, originally restricted to the New World, becomes invasive when introduced into ecosystems out of its natural range of distribution. Invasiveness is anthropically favored by the use of cryptobiotic eggs in the aquaculture and pet trade. The mechanisms of out-competition of the autochthonous Artemia by the invader are still poorly understood. Ecological fitness may play a pivotal role, but other underlying biotic and abiotic factors may contribute. Since the presence of toxicants in hypersaline aquatic ecosystems has been documented, our aim here is to study the potential role of an organophosphate pesticide, chlorpyrifos, in a congeneric mechanism of competition between the bisexual A. franciscana (AF), and one of the Old World parthenogenetic siblings, A. parthenogenetica (PD). For this purpose we carried out life table experiments with both species, under different concentrations of the toxicant (0.1, 1 and 5 μg/l), and analyzed the cholinesterase inhibition at different developmental stages. The results evidence that both, AF and PD, showed an elevated tolerance to high ranges of chlorpyrifos, but AF survived better and its fecundity was less affected by the exposure to the pesticide than that of PD. The higher fecundity of AF is a selective advantage in colonization processes leading to its establishment as NIS. Besides, under the potential selective pressure of abiotic factors, such as the presence of toxicants, its higher resistance in terms of survival and biological

  6. 镰刀菌Fusarium solani菌株对卤虫Artemia salina的毒性%Toxicity of Fusarium solani Strains on Brine Shrimp (Artemia salina)

    Institute of Scientific and Technical Information of China (English)

    Shagufia Hameed; Viqar Sultana; Jehan Ara; Syed Ehteshamul-Haque; Mohammad Athar4

    2009-01-01

    寻找能杀伤肿瘤细胞而对正常细胞无毒的抗癌药物极具挑战性.具有细胞毒性的植物或者真菌可能含有抗肿瘤的化合物.卤虫无节幼体的致死性可作为筛选抗肿瘤化合物的试验.本研究运用从不同农作物种子分离的8株镰刀菌(Fusarium solani)培养滤液来测试卤虫的细胞毒性效果.结果表明,5株菌株(TS、S-29、B-17、C-10和W-5)对卤虫显示高毒性;3株菌株(SR、T-9和L-25)显示低毒性,且毒性随着培养滤液的稀释而减弱.5株菌株(TS、B-17、SR、T-9和L-25)按照1:10稀释能导致30%以上的死亡率.NaOH中和后的滤液毒性略微降低,表明培养滤液的pH值可能影响毒性.这些菌株冻干的滤液相对于未冻干的滤液毒性较低.只在3株温和毒性的菌株中得到正己烷可溶萃取物;氯仿可溶萃取物的鼍极微而不能作进一步处理.各菌株的毒性效果各小相同.从镰刀菌(F.solani)分离的化合物可开发为毒性化合物.%Discovery of anticancer drugs that must kill or disable tumor cells in the presence of normal cells without undue toxicity is an extraordinary challenge. Cytotoxicity of plant or fungal materials is considered as the presence of antitumor compounds. Brine shrimp lethality for larvae (nauplii) is used as prescreening test for the antitumor compounds. In this study, culture filtrates of eight strains of Fusarium solani isolated from seeds of various crops were tested for the toxic effect on brine shrimp. Five of the strains (TS, S-29, B-17, C-10, W-5) showed highest toxic effect and three of the strains (SR, T-9, L-25) showed low toxic activity on brine shrimp. Toxic activity reduced when culture filtrates were diluted. However, F. solani strains TS, B-17, SR, T-9 and L-25 caused more than 30% mortality at 1:10 dilution. Toxic activity was slightly reduced when the filtrates were neutralized with sodium hydroxide indicating possible role of pH of culture filtrate on toxicity. Lyophilized

  7. Phylogeography and local endemism of the native Mediterranean brine shrimp Artemia salina (Branchiopoda: Anostraca)

    DEFF Research Database (Denmark)

    Muñoz, Joaquin; Gómez, Africa; Green, Andy J.;

    2008-01-01

    There has been a recent appreciation of the ecological impacts of zooplanktonic species invasions. The North American brine shrimp Artemia franciscana is one such alien invader in hyper-saline water ecosystems at a global scale. It has been shown to outcompete native Artemia species, leading...... to their local extinction. We used partial sequences of the mitochondrial Cytochrome c Oxidase Subunit 1 (COI or cox1) gene to investigate the genetic diversity and phylogeography of A. salina, an extreme halophilic sexual brine shrimp, over its known distribution range (Mediterranean Basin and South Africa...

  8. Artemia (Crustacea, Anostraca in Chile: a review of basic and applied biology Artemia Crustacea, Anostraca en Chile: revisión de la biología básica y aplicada

    Directory of Open Access Journals (Sweden)

    Patricio De los Rios-Escalante

    2012-09-01

    Full Text Available The brine shrimp Artemia in Chile has been studied since the 1980s, initially on populations inhabiting shallow coastal and inland mountain ponds, and saltworks in northern and central Chile. Based on morphometric and molecular evidence, these populations were identified as A. franciscana. In the 1990s, A. persimilis was recorded from southern Patagonia, a species previously considered endemic to Argentina. Recently, two new populations of A.franciscana have been recorded, from one saline coastal pond in northern Chile and from a saltwork in central Chile. The scope for further research to increase both understanding of the strain characterization and basic population ecology descriptions of the Chilean brine shrimps and improve their conservation status is discussed. It is suggested that future studies should investigate first the management of local brine shrimp population for local aquaculture or conservation resources, other direction would be the effects of ultraviolet radiation (UVR exposition that is notoriously high in brine shrimp habitats. This last factor is very important because the UVR is an important mutagen on the genetic structure of the populations. In this scenario, it is suggest a carefully management for introduced brine shrimp populations for local aquaculture for avoid alterations in native populations that due their genetic isolation would need conservation procedures for avoid local extinctions.El camarón de salmuera o Artemia ha sido estudiado en Chile desde la década de 1980, las primeras descripciones de poblaciones fueron para lagunas someras en zonas costeras y de montana, y en salinas artificiales en la zona central y norte de Chile. Sobre la base de evidencias morfométricas y moleculares estas poblaciones fueron descritas como A. franciscana. En la década de 1990, se describió la presencia de A. persimilis en la zona sur de la Patagonia, lo cual fue una ampliación del rango de distribución significativa

  9. Use of the genus Artemia in ecotoxicity testing

    Energy Technology Data Exchange (ETDEWEB)

    Nunes, Bruno S. [Instituto de Ciencias Biomedicas de Abel Salazar, Departamento de Estudos de Populacoes, Laboratorio de Ecotoxicologia, Universidade do Porto, Largo Prof. Abel Salazar 2, 4099-003 Porto (Portugal) and Centro Interdisciplinar de Investigacao Marinha e Ambiental, Rua dos Bragas 289, 4150-123 Porto (Portugal)]. E-mail: bruno@ufp.pt; Carvalho, Felix D. [REQUIMTE, Departamento de Toxicologia da Faculdade de Farmacia da Universidade do Porto, Rua Anibal Cunha, 164, 4050-047 Porto (Portugal); Guilhermino, Lucia M. [Instituto de Ciencias Biomedicas de Abel Salazar, Departamento de Estudos de Populacoes, Laboratorio de Ecotoxicologia, Universidade do Porto, Largo Prof. Abel Salazar 2, 4099-003 Porto (Portugal); Centro Interdisciplinar de Investigacao Marinha e Ambiental, Rua dos Bragas 289, 4150-123 Porto (Portugal); Van Stappen, Gilbert [Laboratory of Aquaculture and Artemia Reference Centre, Ghent University, Rozier 44, B-9000 Ghent (Belgium)

    2006-11-15

    Information related to varied uses of several species of the genus Artemia (commonly known as brine shrimp), is dispersed among literature from several scientific areas, such as Ecology, Physiology, Ecotoxicology, Aquaculture and Genetics. The present paper reviews information related to Artemia that may be considered relevant for ecotoxicity testing. Integration of different areas of scientific knowledge concerning biology, life cycle and environmental needs of Artemia is of crucial importance when considering the interpretation of results drawn from tests involving this genus. Furthermore, this paper provides suggestions to overcome problems related to toxicity assessment with the use of Artemia as test organism in bioassays, under the scope of estuarine, marine and hypersaline environments. Aspects related to variability in results, adoptable toxicity end-points, culture conditions, characteristics of species and strains, influence of geographical origins over physiological features and responses to exposure to chemical agents are considered. - The physiology, reproductive processes and general use of Artemia in modern ecotoxicological testing are reviewed.

  10. The influence of different rotifer and Artemia enrichment diets on growth, survival and pigmentation in turbot (Scophthalmus maximus L.) larvae

    DEFF Research Database (Denmark)

    Støttrup, Josianne; Attramadal, Y.

    1992-01-01

    , approximately seven days after hatching, the larvae were fed newly-hatched Artemia salina nauplii (AT-1; Brazil strain). From day 10, enriched Great Salt Lake Artemia nauplii were introduced. Each set of seven tansk was further subdivided and the larvae fed Artemia nauplii enriched with one of four enrichment...

  11. HACIA UNA PEDAGOGÍA FRANCISCANA

    Directory of Open Access Journals (Sweden)

    Benjamín Soto Forero

    2008-12-01

    Full Text Available El artículo busca presentar como mediante toda una manera de actuar, de ver y de pensar, se va construyendo una propuesta pedagógica franciscana; inspirada en el Evangelio y en la manera como Francisco de Asís vivió el mismo, buscando siempre la importancia de la persona humana, la fraternidad universal, el respeto por lo diferente, viviendo la cotidianidad de una manera alegre y festiva, donde la propuesta pedagógica franciscana se va dando en el caminar con el otro desde la fraternidad y el servicio.

  12. Embryogenesis, hatching and larval development of Artemia during orbital spaceflight

    Science.gov (United States)

    Spooner, B. S.; Debell, L.; Armbrust, L.; Guikema, J. A.; Metcalf, J.; Paulsen, A.

    1994-08-01

    Developmental biology studies, using gastrula-arrested cysts of the brine shrimp Artemia franciscana, were conducted during two flights of the space shuttle Atlantis (missions STS-37 and STS-43) in 1991. Dehydrated cysts were activated, on orbit, by addition of salt water to the cysts, and then development was terminated by the addition of fixative. Development took place in 5 ml syringes, connected by tubing to activation syringes, containing salt water, and termination syringes, containing fixative. Comparison of space results with simultaneous ground control experiments showed that equivalent percentages of naupliar larvae hatched in the syringes (40%). Thus, reactivation of development, completion of embryogenesis, emergence and hatching took place, during spaceflight, without recognizable alteration in numbers of larvae produced. Post-hatching larval development was studied in experiments where development was terminated, by intrduction of fixative, 2 days, 4 days, and 8 days after reinitiation of development. During spaceflight, successive larval instars or stages, interrupted by molts, occurred, generating brine shrimp at appropriate larval instars. Naupliar larvae possessed the single naupliar eye, and development of the lateral pair of adult eyes also took place in space. Transmission electron microscopy revealed extensive differentiation, including skeletal muscle and gut endoderm, as well as the eye tissues. These studies demonstrate the potential value of Artemia for developmental biology studies during spaceflight, and show that extensive degress of development can take place in this microgravity environment.

  13. Isolation of TDA-producing Phaeobacter strains from sea bass larval rearing units and their probiotic effect against pathogenic Vibrio spp. in Artemia cultures.

    Science.gov (United States)

    Grotkjær, Torben; Bentzon-Tilia, Mikkel; D'Alvise, Paul; Dourala, Nancy; Nielsen, Kristian Fog; Gram, Lone

    2016-05-01

    Fish-pathogenic Vibrio can cause large-scale crashes in marine larval rearing units and, since the use of antibiotics can result in bacterial antibiotic resistance, new strategies for disease prevention are needed. Roseobacter-clade bacteria from turbot larval rearing facilities can antagonize Vibrio anguillarum and reduce mortality in V. anguillarum-infected cod and turbot larvae. In this study, it was demonstrated that antagonistic Roseobacter-clade bacteria could be isolated from sea bass larval rearing units. In addition, it was shown that they not only antagonized V. anguillarum but also V. harveyi, which is the major bacterial pathogen in crustaceans and Mediterranean sea bass larvae cultures. Concomitantly, they significantly improved survival of V. harveyi-infected brine shrimp. 16S rRNA gene sequence homology identified the antagonists as Phaeobacter sp., and in silico DNA-DNA hybridization indicated that they could belong to a new species. The genomes contained genes involved in synthesis of the antibacterial compound tropodithietic acid (TDA), and its production was confirmed by UHPLC-TOFMS. The new Phaeobacter colonized live feed (Artemia) cultures and reduced Vibrio counts significantly, since they reached only 10(4)CFUmL(-1), as opposed to 10(8)CFUmL(-1) in non-Phaeobacter treated controls. Survival of V. anguillarum-challenged Artemia nauplii was enhanced by the presence of wild type Phaeobacter compared to challenged control cultures (89±1.0% vs 8±3.2%). In conclusion, TDA-producing Phaeobacter isolated from Mediterranean marine larviculture are promising probiotic bacteria against pathogenic Vibrio in crustacean live-feed cultures for marine fish larvae. PMID:26922490

  14. Nano-sized polystyrene affects feeding, behavior and physiology of brine shrimp Artemia franciscana larvae

    NARCIS (Netherlands)

    Bergami, Elisa; Bocci, Elena; Vannuccini, Maria Luisa; Monopoli, Marco; Salvati, Anna; Dawson, Kenneth A; Corsi, Ilaria

    2016-01-01

    Nano-sized polymers as polystyrene (PS) constitute one of the main challenges for marine ecosystems, since they can distribute along the whole water column affecting planktonic species and consequently disrupting the energy flow of marine ecosystems. Nowadays very little knowledge is available on th

  15. Coadaptation: lessons from the brine shrimp Artemia, "the aquatic Drosophila" (Crustacea; Anostraca Coadaptación: lecciones desde el camarón de salmuera Artemia, "la Drosophila acuática" (Crustacea; Anostraca

    Directory of Open Access Journals (Sweden)

    GONZALO GAJARDO

    2001-03-01

    Full Text Available During the fifties Brncic and the Dobzhansky's school, using the fruit fly Drosophila as a test organism, introduced the term integration of the genotype, or genetic coadaptation, which has had great impact on thinking in today's evolutionary biology. In this work we use the brine shrimp Artemia - in many respects a sort of aquatic Drosophila- as a model organism to evaluate the relationship between population structure, potential for divergence and the degree of morphological and/or genetic change. These aspects, tightly linked with the organization of the genotype, are important to understanding how recombination and adaptive release of genetic and phenotypic variation affect the speciation process in Artemia. Analysis of genetic (allozyme, diploid and chromocentre numbers, morphological (Mahalanobis distances and reproductive data (cross-fertility tests available for populations of the bisexual, endemic species of the Americas, Artemia franciscana and A. persimilis, indicate that: (i A. franciscana and A. persimilis are morphologically distinct in correspondence with observed genetic differences (D Nei > 1; 2n = 42 and 44; 12.5 and 1.5 mean chromocentre numbers, respectively; (ii populations from Chile and other South American localities (mainly A. franciscana display high levels of genetic variability and a trend to develop large genetic distances between populations; (iii the plasticity of Artemia gene pool is associated, at least in part, with ecological heterogeneity. Hence an adaptive divergence mode is thought to best define the speciation process in Artemia; (iv the succesful production of laboratory hybrids in the allopatric Artemia populations studied in the Americas, a feature seen in other anostracods, could be explained by the fact that formerly allopatric populations have not achieved later sympatry, as required by the allopatric speciation paradigmEn los años cincuenta Brncic y la escuela de Dobzhansky introdujeron el t

  16. Motion control of a population of Artemias

    Directory of Open Access Journals (Sweden)

    L. Fortuna

    2010-06-01

    Full Text Available In this work, the collective behavior of Artemia Salina is studied both experimentally and theoretically. Several experiments have been designed to investigate the Artemia motion under different environment conditions. From the results of such experiments, a strategy to control the direction of motion of an Artemia population, by exploiting their sensitivity to light, has been derived and then implemented.

  17. Origin and genetic diversity of diploid parthenogenetic Artemia in Eurasia.

    Directory of Open Access Journals (Sweden)

    Marta Maccari

    Full Text Available There is wide interest in understanding how genetic diversity is generated and maintained in parthenogenetic lineages, as it will help clarify the debate of the evolution and maintenance of sexual reproduction. There are three mechanisms that can be responsible for the generation of genetic diversity of parthenogenetic lineages: contagious parthenogenesis, repeated hybridization and microorganism infections (e.g. Wolbachia. Brine shrimps of the genus Artemia (Crustacea, Branchiopoda, Anostraca are a good model system to investigate evolutionary transitions between reproductive systems as they include sexual species and lineages of obligate parthenogenetic populations of different ploidy level, which often co-occur. Diploid parthenogenetic lineages produce occasional fully functional rare males, interspecific hybridization is known to occur, but the mechanisms of origin of asexual lineages are not completely understood. Here we sequenced and analysed fragments of one mitochondrial and two nuclear genes from an extensive set of populations of diploid parthenogenetic Artemia and sexual species from Central and East Asia to investigate the evolutionary origin of diploid parthenogenetic Artemia, and geographic origin of the parental taxa. Our results indicate that there are at least two, possibly three independent and recent maternal origins of parthenogenetic lineages, related to A. urmiana and Artemia sp. from Kazakhstan, but that the nuclear genes are very closely related in all the sexual species and parthenogegetic lineages except for A. sinica, who presumable took no part on the origin of diploid parthenogenetic strains. Our data cannot rule out either hybridization between any of the very closely related Asiatic sexual species or rare events of contagious parthenogenesis via rare males as the contributing mechanisms to the generation of genetic diversity in diploid parthenogenetic Artemia lineages.

  18. Real-time PCR detection and quantification of fish probiotic Phaeobacter strain 27-4 and fish pathogenic Vibrio in microalgae, rotifer, Artemia and first feeding turbot (Psetta maxima) larvae

    DEFF Research Database (Denmark)

    Prol, M.J.; Bruhn, Jesper Bartholin; Pintado, J.;

    2009-01-01

    and in presence of microalgae (Isochrysis galbana), rotifers (Brachionus plicatilis), Artemia nauplii or turbot (Psetta maxima) larvae by real-time PCR based on primers directed at genetic loci coding for antagonistic and virulence-related functions respectively. The optimized protocol was used to study...

  19. Multiple {gamma}-glutamylation: A novel type of post-translational modification in a diapausing Artemia cyst protein

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Mai [Bioscience Course, Graduate School of Science and Technology, Niigata University, 2-8050 Ikarashi, Nishi-Ku, Niigata 950-2181 (Japan); Ikeda, Yuka [Institute of High Polymer Research, Faculty of Textile Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda 386-8567 (Japan); Kanzawa, Hideaki [Department of Biology, Faculty of Science, Niigata University, 2-8050 Ikarashi, Nishi-Ku, Niigata 950-2181 (Japan); Sakamoto, Mika [Bioscience Course, Graduate School of Science and Technology, Niigata University, 2-8050 Ikarashi, Nishi-Ku, Niigata 950-2181 (Japan); Goto, Mina [Department of Biology, Faculty of Science, Niigata University, 2-8050 Ikarashi, Nishi-Ku, Niigata 950-2181 (Japan); Tsunasawa, Susumu [Analytical and Measuring Instruments Division, Shimadzu Corporation, Nishinokyo Kuwabaracho 1, Nakagyo-Ku, Kyoto 604-8511 (Japan); Uchiumi, Toshio, E-mail: uchiumi@bio.sc.niigata-u.ac.jp [Bioscience Course, Graduate School of Science and Technology, Niigata University, 2-8050 Ikarashi, Nishi-Ku, Niigata 950-2181 (Japan); Department of Biology, Faculty of Science, Niigata University, 2-8050 Ikarashi, Nishi-Ku, Niigata 950-2181 (Japan); Odani, Shoji [Bioscience Course, Graduate School of Science and Technology, Niigata University, 2-8050 Ikarashi, Nishi-Ku, Niigata 950-2181 (Japan); Department of Biology, Faculty of Science, Niigata University, 2-8050 Ikarashi, Nishi-Ku, Niigata 950-2181 (Japan)

    2010-03-26

    A highly hydrophilic, glutamate-rich protein was identified in the aqueous phenol extract from the cytosolic fraction of brine shrimp (Artemia franciscana) diapausing cysts and termed Artemia phenol soluble protein (PSP). Mass spectrometric analysis revealed the presence of many protein peaks around m/z 11,000, separated by 129 atomic mass units; this value corresponds to that of glutamate, which is strongly suggestive of heterogeneous polyglutamylation. Polyglutamylation has long been known as the functionally important post-translational modification of tubulins, which carry poly(L-glutamic acid) chains of heterogeneous length branching off from the main chain at the {gamma}-carboxy groups of a few specific glutamate residues. In Artemia PSP, however, Edman degradation of enzymatic peptides revealed that at least 13, and presumably 16, glutamate residues were modified by the attachment of a single L-glutamate, representing a hitherto undescribed type of post-translational modification: namely, multiple {gamma}-glutamylation or the addition of a large number of glutamate residues along the polypeptide chain. Although biological significance of PSP and its modification is yet to be established, suppression of in vitro thermal aggregation of lactate dehydrogenase by glutamylated PSP was observed.

  20. Habitat diversity and adaptation to environmental stress in encysted embryos of the crustacean Artemia

    Indian Academy of Sciences (India)

    Joshua A Tanguay; Reno C Reyes; James S Clegg

    2004-12-01

    Encysted embryos (cysts) of the brine shrimp, Artemia, provide excellent opportunities for the study of biochemical and biophysical adaptation to extremes of environmental stress in animals. Among other virtues, this organism is found in a wide variety of hypersaline habitats, ranging from deserts, to tropics, to mountains. One adaptation implicated in the ecological success of Artemia is p26, a small heat shock protein that previous evidence indicates plays the role of a molecular chaperone in these embryos. We add to that evidence here. We summarize recently published work on thermal tolerance and stress protein levels in embryos from the San Francisco Bay (SFB) of California inoculated into experimental ponds in southern Vietnam where water temperatures are much higher. New results on the relative contents of three stress proteins (hsp70, artemin and p26) will be presented along with data on cysts of A. tibetiana collected from the high plateau of Tibet about 4.5 km above sea level. Unpublished results on the stress protein artemin are discussed briefly in the context of this paper, and its potential role as an RNA chaperone. Interestingly, we show that the substantial tolerance of A. franciscana embryos to ultraviolet (UV) light does not seem to result from intracellular biochemistry but, rather, from their surrounding thick shell, a biophysical adaptation of considerable importance since these embryos receive heavy doses of UV in nature.

  1. Biomass production of Artemia in air-water-lift raceway system

    Digital Repository Service at National Institute of Oceanography (India)

    Royan, J.P.; Vijayaraghavan, S.; Krishnakumari, L.

    to 6.3 kg/m 3 in the GSL strain; 3.78 and 4.35 kg/m in the Indian and Sri Lankan strains respectively. The advantages of biomass produc tion of Artcmia through AWL are discussed. Key-words: Artcmia, Biomass, AWL Raceway System Artemia biomass... system is fairly simple. Advantages ofculturing Artemia in raceways are many; different stages of Arternia such as nauplii, pre-adults and adults produced can be used for hatcheries and pet fishery market either in live fonn/frozen or freeze-dried fonn...

  2. Study of model systems to test the potential function of Artemia group 1 late embryogenesis abundant (LEA) proteins.

    Science.gov (United States)

    Warner, Alden H; Guo, Zhi-hao; Moshi, Sandra; Hudson, John W; Kozarova, Anna

    2016-01-01

    Embryos of the brine shrimp, Artemia franciscana, are genetically programmed to develop either ovoviparously or oviparously depending on environmental conditions. Shortly upon their release from the female, oviparous embryos enter diapause during which time they undergo major metabolic rate depression while simultaneously synthesize proteins that permit them to tolerate a wide range of stressful environmental events including prolonged periods of desiccation, freezing, and anoxia. Among the known stress-related proteins that accumulate in embryos entering diapause are the late embryogenesis abundant (LEA) proteins. This large group of intrinsically disordered proteins has been proposed to act as molecular shields or chaperones of macromolecules which are otherwise intolerant to harsh conditions associated with diapause. In this research, we used two model systems to study the potential function of the group 1 LEA proteins from Artemia. Expression of the Artemia group 1 gene (AfrLEA-1) in Escherichia coli inhibited growth in proportion to the number of 20-mer amino acid motifs expressed. As well, clones of E. coli, transformed with the AfrLEA-1 gene, expressed multiple bands of LEA proteins, either intrinsically or upon induction with isopropyl-β-thiogalactoside (IPTG), in a vector-specific manner. Expression of AfrLEA-1 in E. coli did not overcome the inhibitory effects of high concentrations of NaCl and KCl but modulated growth inhibition resulting from high concentrations of sorbitol in the growth medium. In contrast, expression of the AfrLEA-1 gene in Saccharomyces cerevisiae did not alter the growth kinetics or permit yeast to tolerate high concentrations of NaCl, KCl, or sorbitol. However, expression of AfrLEA-1 in yeast improved its tolerance to drying (desiccation) and freezing. Under our experimental conditions, both E. coli and S. cerevisiae appear to be potentially suitable hosts to study the function of Artemia group 1 LEA proteins under environmentally

  3. Artemia cyst production in Russia

    Science.gov (United States)

    Litvinenko, Liudmila I.; Litvinenko, Aleksandr I.; Boiko, Elena G.; Kutsanov, Kirill

    2015-11-01

    In Western Siberia (Russia) there are about 100 Artemia lakes with total area over 1 600 km2. Geographically these lakes are located between 51°-56°N and 61°-82°E. In general these lakes are shallow (depth less than 1.5 m), small or medium size (0.1 to 10 km2); they are chloride; their total salinity is from 40 to 250 g/L. The harvesting of cysts per year is only in 20-40 lakes. In Russia 550 tons of dry Artemia cysts (14%-18% of the world production) were harvested annually. This includes about 350 tons in the Altai region and 200 tons in other regions. During our regular 20-year study period the cyst harvest was: 95 tons in Kurgan; 65 tons in Omsk, 20 tons in Novosibirsk, 20 tons in Tyumen. Ways of increasing cyst harvest in Russia are considered in this article. During the last 30 years the harvest of cysts in Russia has increased from 7-20 to 500-600 tons. A significant influence of dryness of the year was found on productivity in selected lakes, but taken for all the lakes together, the relationship was not significant. The optimal salinity for productivity of cysts in the lakes was determined. Analysis of productivity of the lakes and the harvesting results showed that the stocks of cysts are underutilized by approximately 1.7 times.

  4. The effects of feeding with synbiotic (Pediococcus acidilactici and fructooligosaccharide) enriched adult Artemia on skin mucus immune responses, stress resistance, intestinal microbiota and performance of angelfish (Pterophyllum scalare).

    Science.gov (United States)

    Azimirad, Mahmood; Meshkini, Saeed; Ahmadifard, Nasrollah; Hoseinifar, Seyed Hossein

    2016-07-01

    The aim of this study was to evaluate the effects of feeding on synbiotic (Pediococcus acidilactici and fructooligosaccharide) enriched adult Artemia franciscana on skin mucus immune responses, stress resistance, intestinal microbiota and growth performance of angelfish (Pterophyllum scalare). Three hundred and sixty fish with initial weight 3.2 ± 0.13 g were randomly divided into twelve aquaria (50 L) assigned to four groups in triplicates. Fish were fed for 7 weeks with dietary treatments, including treatment 1: feeding adult Artemia without enrichment (control group), treatment 2: feeding adult Artemia enriched with lyophilised probiotic P. acidilactici (700 mg L(-1)), 3: feeding adult Artemia enriched with prebiotic fructooligosaccharide (FOS) (100 mg L(-1)), group 4: feeding adult Artemia enriched with synbiotic (P. acidilactici (700 mg L(-1)) + FOS (100 mg L(-1))). Skin mucus immune responses (lysozyme activity, total Immunoglobulin and protease), stress resistance against environmental stress (acute decrease of temperature and increase salinity), intestinal microbiota as well as growth indices were measured at the end of feeding trial. Artemia enriched with synbiotic significantly improved growth performance compared to other treatments (P < 0.05). The highest weight gain and specific growth rate (SGR) was observed in synbiotic fed fish (P < 0.05). Compared to the other treatments, the population of lactic acid bacteria was significantly higher in the intestinal microbiota of fish fed synbiotic supplemented diet (P < 0.05). In the environmental stress challenge test, the maximum resistance to abrupt decrease of temperature (17 °C) or elevation of salinity (12 g per liter) was observed in the synbiotic treatment. Also, the total immunoglobulin and lysozyme activity level of skin mucus was significantly elevated in fish fed Artemia enriched with synbiotic (P < 0.05). These results revealed that feeding angelfish with synbiotic

  5. Comparison of the Artemia salina and Artemia fransiscana bioassays for toxicity of Indian medicinal plants

    Directory of Open Access Journals (Sweden)

    Thangapandi Veni

    2014-06-01

    Full Text Available Objective: To evaluate leaves extract of Azima tetracantha and Gmelina asiatica for lethality to brine shrimp larvae (Artemia salina and Artemia fransiscana. Methods: The plant materials were extracted based on polarity gradients of petroleum ether, benzene, chloroform, acetone, ethanol and methanol. The extracts were investigated for their cytotoxic potential. Results: In the brine shrimp lethality assay of all extracts, exception of acetone, ethanol and petroleum ether extracts Gmelina asiatica displayed 100% mortality at 1 000 μg/mL by Artemia salina and Artemia fransiscana. Chloroform extract was the most potent and presented the highest percentage of mortality with the lowest LC50 values by both assay too. Conclusions: The results of the present study suggest the presence of photochemical possessing cytotoxic agents.

  6. Comparison of the Artemia salina and Artemia fransiscana bioassays for toxicity of Indian medicinal plants

    Institute of Scientific and Technical Information of China (English)

    Thangapandi Veni; Thambusamy Pushpanathan

    2014-01-01

    Objective:To evaluate leaves extract of Azima tetracantha and Gmelina asiatica for lethality to brine shrimp larvae (Artemia salina and Artemia fransiscana). Methods: The plant materials were extracted based on polarity gradients of petroleum ether, benzene, chloroform, acetone, ethanol and methanol. The extracts were investigated for their cytotoxic potential. Results: In the brine shrimp lethality assay of all extracts, exception of acetone, ethanol and petroleum ether extracts Gmelina asiatica displayed 100%mortality at 1 000 μg/mL by Artemia salina and Artemia fransiscana. Chloroform extract was the most potent and presented the highest percentage of mortality with the lowest LC50 values by both assay too. Conclusions:The results of the present study suggest the presence of photochemical possessing cytotoxic agents.

  7. Nonhatching Decapsulated Artemia Cysts As a Replacement to Artemia Nauplii in Juvenile and Adult Zebrafish Culture.

    Science.gov (United States)

    Tye, Marc; Rider, Dana; Duffy, Elizabeth A; Seubert, Adam; Lothert, Brogen; Schimmenti, Lisa A

    2015-12-01

    Feeding Artemia nauplii as the main nutrition source for zebrafish is a common practice for many research facilities. Culturing live feed can be time-consuming and requires additional equipment to be purchased, maintained, and cleaned. Nonhatching decapsulated Artemia cysts (decaps) are a commercially available product that can be fed directly to fish. Several other ornamental fish species have been successfully cultured using decaps. Replacing Artemia nauplii with decaps could reduce the overall time and costs associated with the operation of a zebrafish facility. The objective of this study was to determine if decaps could be a suitable replacement to Artemia nauplii in juvenile and adult zebrafish culture. Wild-type zebrafish were fed one of three dietary treatments: decaps only, nauplii only, or a standard consisting of nauplii plus a commercially prepared pellet food. Survival, growth (length and weight), and embryo production were analyzed between the treatments. Fish receiving the decap diet demonstrated a significantly higher growth and embryo production when compared to the fish receiving the nauplii-only diet. When comparing the decap fish to the standard fish, no significant difference was found in mean survival, mean weight at 90 days postfertilization, or mean embryo production. It was determined that nonhatching decapsulated Artemia cysts can be used as a suitable replacement to Artemia nauplii in juvenile and adult zebrafish culture.

  8. Nonhatching Decapsulated Artemia Cysts As a Replacement to Artemia Nauplii in Juvenile and Adult Zebrafish Culture.

    Science.gov (United States)

    Tye, Marc; Rider, Dana; Duffy, Elizabeth A; Seubert, Adam; Lothert, Brogen; Schimmenti, Lisa A

    2015-12-01

    Feeding Artemia nauplii as the main nutrition source for zebrafish is a common practice for many research facilities. Culturing live feed can be time-consuming and requires additional equipment to be purchased, maintained, and cleaned. Nonhatching decapsulated Artemia cysts (decaps) are a commercially available product that can be fed directly to fish. Several other ornamental fish species have been successfully cultured using decaps. Replacing Artemia nauplii with decaps could reduce the overall time and costs associated with the operation of a zebrafish facility. The objective of this study was to determine if decaps could be a suitable replacement to Artemia nauplii in juvenile and adult zebrafish culture. Wild-type zebrafish were fed one of three dietary treatments: decaps only, nauplii only, or a standard consisting of nauplii plus a commercially prepared pellet food. Survival, growth (length and weight), and embryo production were analyzed between the treatments. Fish receiving the decap diet demonstrated a significantly higher growth and embryo production when compared to the fish receiving the nauplii-only diet. When comparing the decap fish to the standard fish, no significant difference was found in mean survival, mean weight at 90 days postfertilization, or mean embryo production. It was determined that nonhatching decapsulated Artemia cysts can be used as a suitable replacement to Artemia nauplii in juvenile and adult zebrafish culture. PMID:25495227

  9. Franciscana strandings on the north coast of Santa Catarina State and insights into birth period

    Directory of Open Access Journals (Sweden)

    Renan Lopes Paitach

    2013-11-01

    Full Text Available Franciscana, Pontoporia blainvillei, is the most threatened small cetacean in the South Atlantic. Accidental captures in fishing nets is the main problem for this species throughout its distribution. Dead franciscanas found along the coast are an important source of information. This work aimed to analyze the records of dead franciscanas found on the northern coast of Santa Catarina, including Babitonga Bay. Between January 2001 and November 2012, 54 franciscana carcasses were recorded, with the highest number (8 individuals in 2011. Fifty-two percent (n=28 of the carcasses were recorded between August and October. Taking into account that this information was not obtained from a systematic effort, it was not possible to consider this as an estimation of mortality. The largest animal was a female, with a total length of 142 cm. Ten recovered animals (18.5% were smaller than 80 cm, and were considered fetuses or calves. These records indicate that the main birthing period for franciscanas in Santa Catarina is between October and January. The findings presented here contribute to our knowledge of franciscana ecology in the state of Santa Catarina.

  10. Historia franciscana y etnografía chiriguana

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    Isabelle Combès

    2015-06-01

    Full Text Available La literatura producida por los franciscanos sobre sus misiones entre los chiriguanos fue fuertemente criticada por ser una apología de la orden y por su pobreza etnográfica. En ella sobresale el impresionante número de historias de las misiones y el reducido número de textos etnográficos, y el desfase entre ambas. Las misiones no existen en las descripciones etnográficas, y los indios desaparecen en las historias de las misiones. La transición de la conversión no está registrada. Impermeables a las creencias nativas, los misioneros no las pensaron como tales; por eso mismo fueron incapaces de arrancarlas y las describieron sin reparos. En un sentido que seguramente no previeron sus autores, la etnografía franciscana de los chiriguanos existe y sigue siendo de inmenso valor para los antropólogos actuales.

  11. Entrophospora schenckii and Pacispora franciscana, arbuscular mycorrhizal fungi (Glomeromycota new for Europe and Poland, respectively

    Directory of Open Access Journals (Sweden)

    Janusz Błaszkowski

    2014-08-01

    Full Text Available Morphological properties of spores of Pacispora franciscana, as well as spores and mycorrhizae of Entrophospora schenckii, arbuscular fungi of the phylum Glomeromycota found for the first time in Poland and Europe, respectively, are described and illustrated. Additionally, the known distribution of the two fungi is presented.

  12. Larvicidal activity of some marine macrophytes against Artemia salina

    Digital Repository Service at National Institute of Oceanography (India)

    PrabhaDevi; Wahidullah, S.; DeSouza, L.; Kamat, S.Y.

    and Microdictyon pseudohapteron, seagrasses (Halophila ovalis and Syringodium isoetifolium and lichens (Umbilicaria arpina) were tested for larvicidal activity using Artemia salina nauplii. The LC50 values for the PE-fraction of M. pseudohapteron and A. muscoides...

  13. Strong environmental tolerance of Artemia under very high pressure

    International Nuclear Information System (INIS)

    It was shown by the present authors group that a tardigrade in its tun-state can survive after exposed to 7.5 GPa for 13 hours. We have extended this experiment to other tiny animals searching for lives under extreme conditions of high hydrostatic pressure. Artemia, a kind of planktons, in its dried egg-state have strong environmental tolerance. Dozens of Artemia eggs were sealed in a small Teflon capsule together with a liquid pressure medium, and exposed to the high hydrostatic pressure of 7.5 GPa. After the pressure was released, they were soaked in seawater to observe hatching rate. It was proved that 80-90% of the Artemia eggs were alive and hatched into Nauplii after exposed to the maximum pressure of 7.5 GPa for up to 48 hours. Comparing with Tardigrades, Artemia are four-times stronger against high pressure.

  14. Specific anion effects in Artemia salina.

    Science.gov (United States)

    Lo Nostro, Pierandrea; Ninham, Barry W; Carretti, Emiliano; Dei, Luigi; Baglioni, Piero

    2015-09-01

    The specific anion effect on the vitality of Artemia salina was investigated by measuring the Lethal Time LT50 of the crustaceans in the presence of different sodium salts solutions at room temperature and at the same ionic strength as natural seawater. Fluoride, thiocyanate and perchlorate are the most toxic agents, while chloride, bromide and sulfate are well tolerated. The rates of oxygen consumption of brine shrimps were recorded in mixed NaCl+NaF or NaCl+NaSCN solutions as a function of time. The results are discussed in terms of the Hofmeister series, and suggest that, besides the biochemical processes that involve F(-), SCN(-) and ClO4(-), the different physico-chemical properties of the strong kosmotropic and chaotropic anions may contribute in determining their strong toxicity for A. salina. PMID:25978674

  15. Morphological analysis of the flippers in the Franciscana dolphin, Pontoporia blainvillei, applying X-ray technique.

    Science.gov (United States)

    Del Castillo, Daniela Laura; Panebianco, María Victoria; Negri, María Fernanda; Cappozzo, Humberto Luis

    2014-07-01

    Pectoral flippers of cetaceans function to provide stability and maneuverability during locomotion. Directional asymmetry (DA) is a common feature among odontocete cetaceans, as well as sexual dimorphism (SD). For the first time DA, allometry, physical maturity, and SD of the flipper skeleton--by X-ray technique--of Pontoporia blainvillei were analyzed. The number of carpals, metacarpals, phalanges, and morphometric characters from the humerus, radius, ulna, and digit two were studied in franciscana dolphins from Buenos Aires, Argentina. The number of visible epiphyses and their degree of fusion at the proximal and distal ends of the humerus, radius, and ulna were also analyzed. The flipper skeleton was symmetrical, showing a negative allometric trend, with similar growth patterns in both sexes with the exception of the width of the radius (P ≤ 0.01). SD was found on the number of phalanges of digit two (P ≤ 0.01), ulna and digit two lengths. Females showed a higher relative ulna length and shorter relative digit two length, and the opposite occurred in males (P ≤ 0.01). Epiphyseal fusion pattern proved to be a tool to determine dolphin's age; franciscana dolphins with a mature flipper were, at least, four years old. This study indicates that the flippers of franciscana dolphins are symmetrical; both sexes show a negative allometric trend; SD is observed in radius, ulna, and digit two; and flipper skeleton allows determine the age class of the dolphins. PMID:24700648

  16. Fine scale distribution constrains cadmium accumulation rates in two geographical groups of Franciscana dolphin from Argentina

    International Nuclear Information System (INIS)

    Highlights: • Fine scale distribution of two Argentine stocks constrains the Cd accumulation rates. • Cadmium levels and accumulation patterns were different between geographic groups. • Marine diet has a major influence than the impact degree of origin environment. • Engraulis anchoita is the main Cd vector species in Argentine shelf for Franciscana. • Information is valuable for the conservation of Franciscana, a vulnerable species. -- Abstract: Franciscana dolphin is an endemic cetacean in the southwestern Atlantic Ocean and is classified as Vulnerable A3d by the International Union for Conservation of Nature. Cadmium accumulation was assessed in two geographic groups from Argentina; one inhabits the La Plata River estuary, a high anthropogenic impacted environment, and the other is distributed in marine coastal, with negligible pollution. Despite the environment, marine dolphins showed an increase of renal Cd concentrations since trophic independence; while in estuarine dolphins was from 6 years. This is associated with dietary Argentine anchovy which was absent in the diet of estuarine dolphins, being a trophic vector of cadmium in shelf waters of Argentina. Cluster analysis also showed high levels of cd in association with the presence of anchovy in the stomach. The difference in the fine scale distribution of species influences dietary exposure to Cd and, along with other data, indicates two stocks in Argentina

  17. Variant subunit specificity in the quaternary structure of Artemia hemoglobin.

    Science.gov (United States)

    Vandenberg, Cassandra J; Matthews, Charles M; Trotman, Clive N A

    2002-08-01

    The brine shrimp Artemia has three extracellular hemoglobins (Hbs) that are developmentally expressed and exhibit distinct oxygen-binding characteristics (Heip, Moens, and Kondo 1978; Heip et al. 1978 ). These Hbs are composed of two polymers, each of which comprises nine covalently linked globin domains. Although the cDNA sequences of two nine-domain globins from Artemia have been published, there is evidence for the existence of further expressed globin genes (Manning, Trotman, and Tate 1990 ). In the present study extensive analysis at the cDNA and genomic levels was performed in order to determine the globin gene copy number in Artemia. Sequence and Southern analysis suggest that four Hb polymers (T1, T2, C1, and C2) are expressed in Artemia. In addition, there is also at least one globin pseudogene. Protein sequencing of the native Hbs revealed that there are limitations on which two polymers can associate. The composition of the Hbs has been determined to be: Hb I, C1C2; Hb II, C1T2; and Hb III, T1T2. These pairings allow the levels of the three Artemia Hbs to be regulated independently by polymer expression alone, therefore explaining the previously inconsistent developmental and hypoxia-induced expression patterns. PMID:12140240

  18. Feeding adult of Artemia salina (Crustacea-Branchiopoda on the dinoflagellate Gyrodinium corsicum (Gymnodiniales and the Chryptophyta Rhodomonas baltica

    Directory of Open Access Journals (Sweden)

    Rauquírio André Albuquerque Marinho da Costa

    2005-07-01

    Full Text Available Experiments were carried out on feeding performance and survival rates of adult Artemia salina exposed to no axenic strains of the dinoflagellate Gyrodinium corsicum and of the Chryptophyta Rhodomonas baltica. Filtration rates on R. baltica and G. corsicum varied from 3.35 to 7.14 ml.artemia-1.h-1 and from 2.97 to 15.86 ml.artemia-1.h-1, respectively. The ingestion rates observed for A. salina did not indicate any digestive dysfunction or physiological impairment for organisms fed on G. corsicum and their functional response were similar to those observed for other organisms like copepod fed on different food concentrations. Mortality rates oscillated from 2.5% to 100% when A. salina was fed on R. baltica or G. corsicum, respectively. Highest mortality rates observed for organisms fed on G. corsicum indicated that this dinoflagellate presented a hazard effect on A. salina that was not possible to confirm if it was related to toxin production or to nutritive inadequacy of this dinoflagellate as food for organisms of this species.Experimentos foram desenvolvidos para estudar as taxas de alimentação e de sobrevivência de Artemia salina alimentada com cepas não tóxicas do dinoflagelado Gyrodinium corsicum e da Chryptophyta Rhodomonas baltica. As taxas de filtração sobre R. baltica e G. corsicum variaram entre 3,35 e 7,14 ml.artemia-1.h-1 e 2,97 e 15,86 ml.artemia-1.h-, respectivamente. As taxas de ingestão observadas para A. salina não indicaram disfunção digestiva ou prejuízo fisiológico nos organismos alimentados com G. corsicum, sendo a resposta funcional destes organismos similar a observada em copépodos alimentados com diferentes concentrações de alimento. As taxas de mortalidade de A. salina oscilaram entre 2,5 e 100% quando alimentada com R. baltica e G. corsicum, respectivamente. As maiores taxas de mortalidade observadas para os organismos alimentados com G. corsicum indicam que este dinoflagelado apresenta algum efeito

  19. EFECTO DEL ENRIQUECIMIENTO DE Artemia FRANCISCANA CON DIFERENTES PROPORCIONES DE ω-3 DHA/EPA SOBRE EL CRECIMIENTO DE JUVENILES DE PEZ BLANCO Menidia estor.

    OpenAIRE

    Hernández Téllez, Ana Rosa

    2012-01-01

    La inclusión de los ácidos grasos ω-3 DHA y EPA en el alimento, es un factor importante para lograr mejor supervivencia y crecimiento en la mayoría de los peces cultivados. Dentro del desarrollo tecnológico para el cultivo del pez blanco de Pátzcuaro Menidia estor, se desconoce el requerimiento de ácidos grasos ω-3 DHA/EPA, y el efecto que éstos tienen en el crecimiento y supervivencia de juveniles en cautiverio. En esta especie como en otras, el alimento vivo (nauplio de Artem...

  20. Effects of Artemia enriched with unsaturated fatty acids and vitamin C on growth, survival and resistance Salmo trutta caspius larvae

    OpenAIRE

    Javaheri baboli, Mehran

    2006-01-01

    This experiment was conducted to investigate the effect of using n-3 HUFA and Vitamin C enriched Artemia urmiana Nauplii Five difference treament were tested: for Caspian salmon (Salmo trutta caspius) larvae compare with artificial food in five treatment: (1) Artificial food, (2) Newly hatched Artemia (3) n-3 HUFA enriched Artemia (4) n-3 HUFA + 10% Ascorbyl Palmitate enriched Artemia (5) n-3 HUFA+20% Ascorbyl palmitate enriched Artemia during 15 days then all treatment were fe...

  1. Beak deviations in the skull of Franciscana dolphins Pontoporia blainvillei from Argentina.

    Science.gov (United States)

    Denuncio, Pablo; Panebianco, M Victoria; Del Castillo, Daniela; Rodríguez, Diego; Cappozzo, H Luis; Bastida, Ricardo

    2016-06-15

    The Franciscana dolphin Pontoporia blainvillei is characterized by a long rostrum, a feature that is shared with the families formerly classified as river dolphins (Pontoporiidae, Platanistidae, Iniidae, Lipotidae). Although there are occasional reports on the existence of beak deformations, very little published information exists describing this process. The object of the present study was to describe and quantify the beak anomalies of Franciscana dolphins from the coastal waters of Argentina. Of 239 skulls analyzed 12% showed beak deviations (BD), affecting the premaxillary-maxillary and dentary bones to different extents. The occurrence of BD in the dentary bone represented 58%, whereas premaxillary-maxillary BDs were observed in 14% of the studied specimens, while the complete rostrum (dentary, premaxillary and maxillary) was affected in 28% of the skulls. Dorsoventral axis BD was more frequent than lateral BD (48 and 38%, respectively), and double BD was only observed in the dentary bone. Most of the BD observed in this study could be classified as mild/moderate, and we assume that it did not affect the feeding activities of individuals; however, 2 specimens (dolphin in different ways. A more detailed and thorough study of these cranial anomalies is necessary.

  2. Plastic ingestion in Franciscana dolphins, Pontoporia blainvillei (Gervais and d'Orbigny, 1844), from Argentina.

    Science.gov (United States)

    Denuncio, Pablo; Bastida, Ricardo; Dassis, Mariela; Giardino, Gisela; Gerpe, Marcela; Rodríguez, Diego

    2011-08-01

    Plastic debris (PD) ingestion was examined in 106 Franciscana dolphins (Pontoporia blainvillei) incidentally captured in artisanal fisheries of the northern coast of Argentina. Twenty-eight percent of the dolphins presented PD in their stomach, but no ulcerations or obstructions were recorded in the digestive tracts. PD ingestion was more frequent in estuarine (34.6%) than in marine (19.2%) environments, but the type of debris was similar. Packaging debris (cellophane, bags, and bands) was found in 64.3% of the dolphins, with a lesser proportion (35.7%) ingesting fishery gear fragments (monofilament lines, ropes, and nets) or of unknown sources (25.0%). PD ingestion correlated with ontogenetic changes in feeding regimes, reaching maximum values in recently weaned dolphins. Because a simultaneous increase in gillnet entanglement and the bioaccumulation of heavy metals take place at this stage, the first months after trophic independence should be considered as a key phase for the conservation of Franciscana dolphin stocks in northern Argentina. PMID:21616509

  3. Environmental predictors of habitat suitability and biogeographical range of Franciscana dolphins (Pontoporia blainvillei

    Directory of Open Access Journals (Sweden)

    Jonatan J. Gomez

    2015-01-01

    Full Text Available The aim of this study was to use species distribution models to estimate the effects of environmental variables on the habitat suitability of river dolphins Pontoporia blainvillei (franciscanas along their overall biogeographical distribution. Based on the literature, we selected six environmental variables to be included in the models; four climatic factors (surface sea temperature, salinity, turbidity and productivity and two biotic factors (prey availability and fishing effort. We determined that the biographic range is under the following limits: temperature less than 19°C, a salinity of 36 psu and a minimal probability of the occurrence of fish C. guatucupa of 0.297. In the discussion, we postulate hypotheses on the behavioural and physiological mechanisms that cause these associations between environmental predictors and Franciscanas distribution. There was a good fit between the distribution predicted by the species distribution model and the one proposed by the experts of the International Union for Conservation of Nature; however, our analysis failed to highlight the fundamental role of bycatch as the main threat to this dolphin species.

  4. The brine shrimp Artemia: adapted to critical life conditions

    Directory of Open Access Journals (Sweden)

    Gonzalo M Gajardo

    2012-06-01

    Full Text Available The brine shrimp Artemia is a micro-crustacean, well adapted to the harsh conditions that severely hypersaline environments impose on survival and reproduction. Adaptation to these conditions has taken place at different functional levels or domains, from the individual (molecular-cellular-physiological to the population level. Such conditions are experienced by very few equivalent macro-planktonic organisms; thus, Artemia can be considered a model animal extremophile offering a unique suite of adaptations that are the focus of this review. The most obvious is a highly efficient osmoregulation system to withstand up to 10 times the salt concentration of ordinary seawater. Under extremely critical environmental conditions, for example when seasonal lakes dry out, Artemia takes refuge by producing a highly resistant encysted gastrula embryo (cyst capable of severe dehydration enabling an escape from population extinction. Cysts can be viewed as gene banks that store a genetic memory of historical population conditions. Their occurrence is due to the evolved ability of females to perceive forthcoming unstable environmental conditions expressed by their ability to switch reproductive mode, producing either cysts (oviparity when environmental conditions become deleterious or free-swimming nauplii (ovoviviparity that are able to maintain the population under suitable conditions.At the population level the trend is for conspecific populations to be fragmented into locally adapted populations, whereas species are restricted to salty lakes in particular regions (regional endemism. The Artemia model depicts adaptation as a complex response to critical life conditions, integrating and refining past and present experiences at all levels of organization. Although we consider an invertebrate restricted to a unique environment, the processes to be discussed are of general biological interest. Finally, we highlight the benefits of understanding the stress

  5. Probing the phenomenon of trained immunity in invertebrates during a transgenerational study, using brine shrimp Artemia as a model system.

    Science.gov (United States)

    Norouzitallab, Parisa; Baruah, Kartik; Biswas, Priyanka; Vanrompay, Daisy; Bossier, Peter

    2016-01-01

    The invertebrate's innate immune system was reported to show some form of adaptive features, termed trained immunity. However, the memory characteristics of innate immune system and the mechanisms behind such phenomena remain unclear. Using the invertebrate model Artemia, we verified the possibility or impossibility of trained immunity, examining the presence or absence of enduring memory against homologous and heterologous antigens (Vibrio spp.) during a transgenerational study. We also determined the mechanisms behind such phenomenon. Our results showed the occurrence of memory and partial discrimination in Artemia's immune system, as manifested by increased resistance, for three successive generations, of the progenies of Vibrio-exposed ancestors towards a homologous bacterial strain, rather than to a heterologous strain. This increased resistance phenotype was associated with elevated levels of hsp70 and hmgb1 signaling molecules and alteration in the expression of key innate immunity-related genes. Our results also showed stochastic pattern in the acetylation and methylation levels of H4 and H3K4me3 histones, respectively, in the progenies whose ancestors were challenged. Overall results suggest that innate immune responses in invertebrates have the capacity to be trained, and epigenetic reprogramming of (selected) innate immune effectors is likely to have central place in the mechanisms leading to trained immunity. PMID:26876951

  6. Comparison live adult Artemia and squid meat on the growth of Penaeid shrimp Metapenaeus dobsoni (Miers)

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, S.R.S.; Achuthankutty, C.T.; Royan, J.P.

    An experiment lasting 14 weeks was conducted to compare the efficiency of live adult Artemia with fresh squid meat on growth of penaeid shrimp Metapenaeus dobsoni. The shrimps were found actively feeding on live Artemia and grew 84% more than those...

  7. Radiation Damage to Artemia Cysts:Effects of Water Vapor.

    Science.gov (United States)

    Snipes, W C; Gordy, W

    1963-10-25

    Water vapor altered the form and greatly increased the rate of decay of the electron-spin resonance pattern of long-lived free radicals obtained upon gamma irradiation of Artemia salina cysts ( brine shrimp eggs). These results, combined with data on radiation survival, indicate that the water vapor protects the cysts from radiation damage, or heals the damage. They also indicate that water protects the cysts from the effect of oxygen by neutralizing the radiation-induced free radicals before they can interact with oxygen to produce irreversible damage. PMID:17748168

  8. Isolation by environmental distance in mobile marine species: molecular ecology of franciscana dolphins at their southern range.

    Science.gov (United States)

    Mendez, Martin; Rosenbaum, Howard C; Subramaniam, Ajit; Yackulic, Charles; Bordino, Pablo

    2010-06-01

    The assessment of population structure is a valuable tool for studying the ecology of endangered species and drafting conservation strategies. As we enhance our understanding about the structuring of natural populations, it becomes important that we also understand the processes behind these patterns. However, there are few rigorous assessments of the influence of environmental factors on genetic patterns in mobile marine species. Given their dispersal capabilities and localized habitat preferences, coastal cetaceans are adequate study species for evaluating environmental effects on marine population structure. The franciscana dolphin, a rare coastal cetacean endemic to the Western South Atlantic, was studied to examine these issues. We analysed genetic data from the mitochondrial DNA and 12 microsatellite markers for 275 franciscana samples utilizing frequency-based, maximum-likelihood and Bayesian algorithms to assess population structure and migration patterns. This information was combined with 10 years of remote sensing environmental data (chlorophyll concentration, water turbidity and surface temperature). Our analyses show the occurrence of genetically isolated populations within Argentina, in areas that are environmentally distinct. Combined evidence of genetic and environmental structure suggests that isolation by distance and a process here termed isolation by environmental distance can explain the observed correlations. Our approach elucidated important ecological and conservation aspects of franciscana dolphins, and has the potential to increase our understanding of ecological processes influencing genetic patterns in other marine species. PMID:20465582

  9. Vibrio hispanicus sp. nov., isolated from Artemia sp. and sea water in Spain.

    Science.gov (United States)

    Gomez-Gil, B; Thompson, F L; Thompson, C C; Garcia-Gasca, A; Roque, A; Swings, J

    2004-01-01

    Three Gram-negative, small, motile, rod-shaped bacteria were isolated from Artemia sp. and sea water in Barcelona, Spain, during 1990 and 1991. They were fermentative, oxidase-positive, sensitive to vibriostatic agent O/129, arginine dihydrolase-positive, lysine and ornithine decarboxylase-negative and grew in the absence of NaCl. They differed from phenotypically related species by their ability to grow at 4 degrees C and utilize L-rhamnose. Cloning of the 16S rRNA gene of the type strain produced two different 16S rRNA gene sequences, which differed by 15 bases (0.99%); comparison of these sequences with those deposited in GenBank showed close relationships with Vibrio proteolyticus (97.6% similarity), Vibrio diazotrophicus (97.9%), Vibrio campbellii (96.8%) and Vibrio alginolyticus (96.8%), among others. DNA-DNA hybridization levels with the closest phylogenetically related Vibrio species were Vibrio, for which the name Vibrio hispanicus sp. nov. is proposed, with the type strain LMG 13240T (=CAIM 525T=VIB 213T).

  10. Cadmium and zinc reversibly arrest development of Artemia larvae

    Energy Technology Data Exchange (ETDEWEB)

    Bagshaw, J.C.; Rafiee, P.; Matthews, C.O.; MacRae, T.H.

    1986-08-01

    Despite the widespread distribution of heavy metals such as cadmium and zinc in the environment and their well-known cytotoxicity and embryotoxicity in mammals, comparatively little is known about their effect on aquatic organisms, particularly invertebrates. Post-gastrula and early larval development of the brine shrimp, Artemia, present some useful advantages for studies of developmental aspects of environmental toxicology. Dormant encysted gastrulae, erroneously called brine shrimp eggs, can be obtained commercially and raised in the laboratory under completely defined conditions. Following a period of post-gastrula development within the cyst, pre-nauplius larvae emerge through a crack in the cyst shell. A few hours later, free-swimming nauplius larvae hatch. Cadmium is acutely toxic to both adults and nauplius larvae of Artemia, but the reported LC50s are as high as 10 mM, depending on larval age. In this paper the authors show that pre-nauplius larvae prior to hatching are much more sensitive to cadmium than are hatched nauplius larvae. At 0.1 ..mu..m, cadmium retards development and hatching of larvae; higher concentrations block hatching almost completely and thus are lethal. However, the larvae arrested at the emergence stage survive for 24 hours or more before succumbing to the effects of cadmium, and during this period the potentially lethal effect is reversible if the larvae are placed in cadmium-free medium. The effects of zinc parallel those of cadmium, although zinc is somewhat less toxic than cadmium at equal concentrations.

  11. Prey consumed by Guiana dolphin Sotalia guianensis (Cetacea, Delphinidae and franciscana dolphin Pontoporia blainvillei (Cetacea, Pontoporiidae in an estuarine environment in southern Brazil

    Directory of Open Access Journals (Sweden)

    Marta J. Cremer

    2012-06-01

    Full Text Available The present study provides information about the diet of sympatric populations of small cetaceans in the Babitonga Bay estuary. This is the first study on the diet of these species in direct sympatry. The stomach contents of seven Guiana dolphins Sotalia guianensis and eight franciscanas Pontoporia blainvillei were analyzed. The prey of both cetaceans was mostly teleost fishes, followed by cephalopods. We identified 13 teleost fishes as part of the diet of the franciscanas, and 20 as part of the diet of Guiana dolphins. Lolliguncula brevis was the only cephalopod recorded, and was the most important prey for both cetaceans. Stellifer rastrifer and Gobionellus oceanicus were also important for franciscana, so as Mugil curema and Micropogonias furnieri were important for Guiana dolphins. Stellifer rastrifer and Cetengraulis edentulus were the fishes with the highest frequency of occurrence for franciscana (50%, while Achirus lineatus, C. edentulus, S. brasiliensis, Cynoscion leiarchus, M. furnieri, M. curema, Diapterus rhombeus, Eugerres brasilianus and G. oceanicus showed 28.6% of frequency of occurrence for Guiana dolphins. Franciscanas captured greater cephalopods than the Guiana dolphins in both total length (z= -3.38; n= 40; p< 0.05 and biomass (z = -2.46; n = 40; p<0.05. All of the prey species identified occur inside the estuary, which represents a safe habitat against predators and food availability, reinforcing the importance of the Babitonga Bay for these cetacean populations.

  12. Diffusive properties of water in Artemia cysts as determined from quasi-elastic neutron scattering spectra. [Artemia shrimp

    Energy Technology Data Exchange (ETDEWEB)

    Trantham, E.C.; Rorschach, H.E.; Clegg, J.S.; Hazlewood, C.F.; Nicklow, R.M.; Wakabayashi, N.

    1984-05-01

    Results have been obtained on the quasi-elastic spectra of neutrons scattered from pure water, 20% agarose gel (hydration four grams H/sub 2/O per gram of dry solid) and cysts of the brine shrimp Artemia for hydrations between 0.10 and 1.2 grams H/sub 2/O per gram of dry solids. The spectra were interpreted using a two-component model that included contributions from the covalently bonded protons and the hydration water, and a mobile water fraction. The mobile fraction was described by a jump-diffusion correlation function for the translation motion and a simple diffusive orientational correlation function. The results for the line widths ..gamma..(Q/sup 2/) for pure water were in good agreement with previous measurements. The agarose results were consistent with NMR measurements that show a slightly reduced translational diffusion for the mobile water fraction. The Artemia results show that the translational diffusion coefficient of the mobile water fraction was greatly reduced from that of pure water. The line width was determined mainly by the rotational motion, which was also substantially reduced from the pure water value as determined from dielectric relaxation studies. The translational and rotational diffusion parameters were consistent with the NMR measurements of diffusion and relaxation. Values for the hydration fraction and the mean square thermal displacement as determined from the Q-dependence of line areas were also obtained.

  13. THE BRINE SHRIMP (ARTEMIA SALINA) LETHALITY OF Brassica oleracea var. capitata

    OpenAIRE

    O. T. TÜZÜN, E. GÜRKAN, S. DOĞANCA, F. HIRLAK,

    2015-01-01

    This work covers up the bio-activities of the five fractions obtained from the ethanolic extract of Brassica oleracea var. capitata (Cruciferae).Key Words: Brassica oleracea var. capitata, Brine shrimp (Artemia salina)

  14. Toxic Assessment of Triclosan and Triclocarban on Artemia salina.

    Science.gov (United States)

    Xu, Xiaolu; Lu, Yin; Zhang, Deyong; Wang, Yinyin; Zhou, Xianshan; Xu, Huiying; Mei, Yu

    2015-12-01

    In this study, we investigated the possible acute toxic and genotoxic effects of triclosan (TCS) and triclocarban (TCC) on Artemia salina. Genotoxicity was evaluated using single-cell gel electrophoresis and apoptotic frequency assays (Annexin V-FITC/PI assay). Acute toxicity test results showed that TCC (LC50-24 h = 17.8 µg/L) was more toxic than TCS (LC50-24 h = 171.1 µg/L). Significant increases in both genotoxic biomarkers were observed at 24 h after initial exposure, indicating that these two chemicals are potentially dangerous for this aquatic biological model. Although further studies are required, a comparison of data both in vitro and in vivo allowed us to suggest possible mechanisms of action for TCS and TCC in this sentinel organism. PMID:26310128

  15. Potentials of converting microalgae into brine shrimp Artemia

    OpenAIRE

    Sorgeloos, P

    1985-01-01

    High densities of brine shrimp Artemia can be cultured in flow-through systems using the effluent of microalgae cultures as a combined source of culture medium and food. It has been proven at the "St. Croix Artificial Upwelling Mariculture Project" that in comparison with the fast growing clam Tapes japonica, brine shrimp assure a much more efficient conversion of plant into animal biomass. It appears from the given examples that microalgae conversion into brine shrimp Artemia offers efficien...

  16. Evaluation of mono- and mixed diets as food for intensive Artemia culture

    OpenAIRE

    Lavens, P.; De Meulemeester, A.; Sorgeloos, P.

    1987-01-01

    In order to alleviate the problems encountered when using live algae or rice bran as Artemia food in intensive culturing, different alternative types of brine shrimp diets have been evaluated. Using a high-density flow-through recirculation culture system, a Single Cell Protein yeast and mixed diets, consisting of this yeast and micronized waste products from agricultural corps, were selected as suitable Artemia feeds.Production yields after 2 weeks culturing varied from 2 to 5 kg live weight...

  17. Population Genetics of Franciscana Dolphins (Pontoporia blainvillei): Introducing a New Population from the Southern Edge of Their Distribution

    Science.gov (United States)

    Gariboldi, María Constanza; Túnez, Juan Ignacio; Dejean, Cristina Beatriz; Failla, Mauricio; Vitullo, Alfredo Daniel; Negri, María Fernanda; Cappozzo, Humberto Luis

    2015-01-01

    Due to anthropogenic factors, the franciscana dolphin, Pontoporia blainvillei, is the most threatened small cetacean on the Atlantic coast of South America. Four Franciscana Management Areas have been proposed: Espiritu Santo to Rio de Janeiro (FMA I), São Paulo to Santa Catarina (FMA II), Rio Grande do Sul to Uruguay (FMA III), and Argentina (FMA IV). Further genetic studies distinguished additional populations within these FMAs. We analyzed the population structure, phylogeography, and demographic history in the southernmost portion of the species range. From the analysis of mitochondrial DNA control region sequences, 5 novel haplotypes were found, totalizing 60 haplotypes for the entire distribution range. The haplotype network did not show an apparent phylogeographical signal for the southern FMAs. Two populations were identified: Monte Hermoso (MH) and Necochea (NC)+Claromecó (CL)+Río Negro (RN). The low levels of genetic variability, the relative constant size over time, and the low levels of gene flow may indicate that MH has been colonized by a few maternal lineages and became isolated from geographically close populations. The apparent increase in NC+CL+RN size would be consistent with the higher genetic variability found, since genetic diversity is generally higher in older and expanding populations. Additionally, RN may have experienced a recent split from CL and NC; current high levels of gene flow may be occurring between the latter ones. FMA IV would comprise four franciscana dolphin populations: Samborombón West+Samborombón South, Cabo San Antonio+Buenos Aires East, NC+CL+Buenos Aires Southwest+RN and MH. Results achieved in this study need to be taken into account in order to ensure the long-term survival of the species. PMID:26221960

  18. Nutritional Content of Artemia sp. Fed with Chaetoceros calcitrans and Skeletonema costatum

    Directory of Open Access Journals (Sweden)

    VIVI ENDAR HERAWATI

    2014-12-01

    Full Text Available Artemia sp. is a natural food with high protein content, especially amino acid. Nowadays, Indonesia still relies on import for its supply. Hence, the utilization of local Artemia sp. as an alternative to the imported product is recommended as it contains more protein and less expensive. The advantages of local Artemia sp. is its better crystal quality as it is still fresh. It also provides better income for salt farmers because waste water from salt farm can be used to culture Artemia sp.. This research is aimed at determining the quality of locally-produced Artemia sp., by evaluation of its essential amino acid and fatty acid profiles after treatments. Our results indicated that Artemia sp. cysts with good quality were produced after 8 hours and Artemia sp. reaches a hatching rate of 1,320,000 cysts (95% after 27 hours. We also found an indication that the best feed concentration was a mix of 60% Chaetoceros calcitrans with 40% Skeletonema costatum. Fatty acid profile analyses showed that the highest SAFA (12.86% and PUFA (29.91% were gained after feeding with Chaetoceros calcitrans, whereas the highest HUFA (4.93% was gained after feeding with Skeletonemacostatum. Essential amino acid profile analyses revealed the highest content of amino acid (18912.62 ppm was after feeding with a combination of Chaetoceros calcitrans and Skeletonema costatum. Finally, the proper water quality during research was at 25-30 oC of temperature, 30-31 ppt of salinity, pH 7.8-8.9, and DO was at 3.0-4.4 mg/L.

  19. Purification and characterization of a carboxymethyl cellulase from Artemia salina.

    Science.gov (United States)

    Zin, Hyun Woo; Park, Kwang-Hyun; Choi, Tae Jin

    2014-01-01

    Brine shrimp (Artemia salina) belong to a group of crustaceans that feed on microalgae and require a cellulase enzyme that can be used in ethanol production from marine algae. Protein with potential cellulase activity was purified and the activity analyzed under different conditions. After initial identification of cellulase activity by CMC cellulase, surface sterilization and PCR using 16s rRNA primers was conducted to confirm that the cellulase activity was not produced from contaminating bacteria. The enzyme was purified by ammonium sulfate fractionation, gel filtration, and ion exchange chromatography. After the final purification, a 70-fold increase in specific enzyme activity was observed. SDS-PAGE results revealed that the cellulase enzyme had a molecular mass of 96 kDa. Temperature, pH, and salinity values were found to be optimal at 55 °C, pH 8.0, and 600 mM NaCl, respectively. Specifically, the enzyme showed a fivefold increase in enzyme activity in seawater compared to 600 mM NaCl in phosphate buffer. Further analysis of the purified enzyme by molecular spectrometry showed no match to known cellulases, indicating this enzyme could be a novel halophilic cellulase that can be used for the production of bioethanol from marine macroalgae. PMID:24291747

  20. TÓXICIDAD DE LA APITOXINA EN UN MODELO DE Artemia salina

    Directory of Open Access Journals (Sweden)

    Juan Manuel Pérez Agudelo

    2015-06-01

    Full Text Available Objetivo:Determinar la toxicidad del extracto acuoso de Apitoxina mediante bioprospección en el modelo de Artemia salina. Materiales y métodos: Previo montaje de Biorreactor, un grupo fue expuesto al extracto acuoso de Apitoxina (n=20 y el grupo control fue expuesto a agua destilada (n=20 la toxicidad se definió por la muerte de la Artemia salina a las 24 horas de administración del extracto. Se realizó análisis estadístico no paramétrico mediante la prueba de Chi cuadrado de homogeneidad (Pearson para determinar la diferencia en mortalidad de los grupos.Resultados:El Grupo Control no presentó mortalidad, en tanto el Grupo Apitoxina presentó una mortalidad del 95%. Se demostró una asociación estadísticamente significativa con un p<0,05(IC: 95% entre la mortalidad de la Artemia salina y la administración de apitoxina.Conclusión:El extracto acuoso de apitoxina presenta toxicidad a una concentración de 0.35 en el modelo de Artemia salina. Palabras Clave: Apitoxina, Artemia salina, Toxicidad

  1. Stress tolerance during diapause and quiescence of the brine shrimp, Artemia.

    Science.gov (United States)

    MacRae, Thomas H

    2016-01-01

    Oviparously developing embryos of the brine shrimp, Artemia, arrest at gastrulation and are released from females as cysts before entering diapause, a state of dormancy and stress tolerance. Diapause is terminated by an external signal, and growth resumes if conditions are permissible. However, if circumstances are unfavorable, cysts enter quiescence, a dormant stage that continues as long as adverse conditions persist. Artemia embryos in diapause and quiescence are remarkably resistant to environmental and physiological stressors, withstanding desiccation, cold, heat, oxidation, ultraviolet radiation, and years of anoxia at ambient temperature when fully hydrated. Cysts have adapted to stress in several ways; they are surrounded by a rigid cell wall impermeable to most chemical compounds and which functions as a shield against ultraviolet radiation. Artemia cysts contain large amounts of trehalose, a non-reducing sugar thought to preserve membranes and proteins during desiccation by replacing water molecules and/or contributing to vitrification. Late embryogenesis abundant proteins similar to those in seeds and other anhydrobiotic organisms are found in cysts, and they safeguard cell organelles and proteins during desiccation. Artemia cysts contain abundant amounts of p26, a small heat shock protein, and artemin, a ferritin homologue, both ATP-independent molecular chaperones important in stress tolerance. The evidence provided in this review supports the conclusion that it is the interplay of these protective elements that make Artemia one of the most stress tolerant of all metazoan organisms. PMID:26334984

  2. Artemia parthenogenetica (Branchiopoda: Anostraca) from the Large Aral Sea: Abundance, distribution, population structure and cyst production

    Science.gov (United States)

    Arashkevich, Elena G.; Sapozhnikov, P. V.; Soloviov, K. A.; Kudyshkin, T. V.; Zavialov, P. O.

    2009-03-01

    The brine shrimp Artemia parthenogenetica appeared in the Large Aral Sea (Central Asia) in 1998 when mineralization reached 63 ppt. Data on Artemia abundance and biomass, along with temperature and salinity measurements were collected in the western basin during 2002-2006, primarily in the autumn. During the study period, population density grew progressively, both in terms of number, from 250 to 1260 individuals per m 3, and in terms of biomass, from 0.3 to 1.3 g per m 3. In 2005, the population density and spatial distribution in the different parts of the sea (western and eastern basins and strait) was assessed. The horizontal distribution of the Artemia population was uniform in the deep central part of the western basin, although the distribution was quite patchy in the shallow coastal zone. Depth habitat of Artemia was restricted to the upper 20-25 m of depth, as the oxygen depletion and formation of anoxic layer prevented distribution of Artemia to the deeper waters. In autumn, all females reproduced oviparously, with an average clutch size of 30-35 eggs per female. The number of eggs in a clutch was positively correlated with female body length ( r2 = 0.36-0.44).

  3. Global biodiversity and geographical distribution of diapausing aquatic invertebrates: the case of the cosmopolitan brine shrimp, Artemia (Branchiopoda, Anostraca)

    DEFF Research Database (Denmark)

    Muñoz, Joaquin; Pacios, Fernando

    2010-01-01

    The genus Artemia comprises passively dispersed anostracan species with a distribution all around the world, except in Antarctica. We used both published and personal data to assess and update existing knowledge on the diversity and distribution of Artemia, in particular compiling also genetic an...

  4. Purification and characterization of phenoloxidase from brine shrimp Artemia sinica

    Institute of Scientific and Technical Information of China (English)

    Tingjun Fan; Zhao Jing; Xianyuan Fan; Miaomiao Yu; Guojian Jiang

    2011-01-01

    Phenoloxidase from Artemia sinica (AsPO) was purified by Superdex 200 gel-filtration and Q Sepharose fast flow ionexchange chromatography,and its properties were characterized biochemically and enzymatically by using L-dihydroxyphenylalanine (L-DOPA) as the specific substrate.Results showed that AsPO was isolated as a monomeric protein of 125.5 kDa in molecular mass.The optimal pH value and temperature are 7.0 and 50℃,respectively,for its PO activity.The AsPO had an apparent Km value of 4.2 mM on L-DOPA,and 10.9 mM on catechol,respectively.Oxidase inhibitor on PO activity showed that the AsPO was extremely sensitive to ascorbic acid,sodium sulfite,and citric acid; and was very sensitive to cysteine,benzoic acid,and l-phenyl-2-thiourea.Combined with its specific enzyme activity on L-DOPA and catechol,it can be concluded that AsPO is most probably a typical catechol-type O-diphenoloxidase.Its PO activity was also sensitive to metal ions and chelators,and 20 mM DETC-inhibited PO activity was obviously recovered by 15 mM Cu2+,indicating that AsPO is most probably a copper-containing metalloenzyme.All these data about specific substrate,sensitivity to oxidase inhibitor metal ions and chelators indicate that the AsPO has the properties of a catechol-type copper-containing Odiphenoloxidase that functions as a vital humoral factor in host defense via melaninization as in other Crustaceans.

  5. TÓXICIDAD DE LA APITOXINA EN UN MODELO DE Artemia salina

    OpenAIRE

    Juan Manuel Pérez Agudelo; Juan Felipe Salazar Espinosa; Jorge Hernán Hernández Guevara

    2015-01-01

    Objetivo:Determinar la toxicidad del extracto acuoso de Apitoxina mediante bioprospección en el modelo de Artemia salina. Materiales y métodos: Previo montaje de Biorreactor, un grupo fue expuesto al extracto acuoso de Apitoxina (n=20) y el grupo control fue expuesto a agua destilada (n=20) la toxicidad se definió por la muerte de la Artemia salina a las 24 horas de administración del extracto. Se realizó análisis estadístico no paramétrico mediante la prueba de Chi cuadrado de homogeneidad (...

  6. Intracellular water in Artemia cysts (brine shrimp): Investigations by deuterium and oxygen-17 nuclear magnetic resonance

    OpenAIRE

    Kasturi, S. R.; Seitz, P. K.; Chang, D. C.; Hazlewood, C. F.

    1990-01-01

    The dormant cysts of Artemia undergo cycles of hydration-dehydration without losing viability. Therefore, Artemia cysts serve as an excellent intact cellular system for studying the dynamics of water-protein interactions as a function of hydration. Deuterium spin-lattice (T1) and spin-spin (T2) relaxation times of water in cysts hydrated with D2O have been measured for hydrations between 1.5 and 0.1 g of D2O per gram of dry solids. When the relaxation rates (I/T1, I/T2) of 2H and 17O are plot...

  7. Bacteria contribute to Artemia nutrition in algae-limited conditions: A laboratory study

    OpenAIRE

    Toi, H.T.; P. Boeckx; Sorgeloos, P.; Bossier, P; Van Stappen, G.

    2013-01-01

    We investigated the effect of the stimulation of bacterial growth on Artemia performance in combination with a standard and with a low algal feeding regime. In both regimes, organic carbon (supplied as sucrose or soluble potato starch) and 15N labeled inorganic nitrogen (supplied as NaNO3) were used to stimulate bacterial growth in the Artemia cultures at C/N ratio 10 and 50. After a culture period of 15 days, significantly improved biomass production was obtained in all treatments with the l...

  8. The role of metallothioneins, selenium and transfer to offspring in mercury detoxification in Franciscana dolphins (Pontoporia blainvillei).

    Science.gov (United States)

    Romero, M B; Polizzi, P; Chiodi, L; Das, K; Gerpe, M

    2016-08-15

    The concentrations of mercury (Hg), selenium (Se) and metallothioneins (MT) were evaluated in fetuses, calves, juveniles and adults of the endangered coastal Franciscana dolphin (Pontoporia blainvillei) from Argentina. Mercury concentrations varied among analyzed tissues (liver, kidney, muscle and brain), with liver showing the higher concentrations in all specimens. An age-dependent accumulation was found in liver, kidney and brain. No significant relationship between Hg and MT concentrations was found for all tissues analyzed. Hepatic Hg molar concentrations were positively correlated with those of Se, indicating a great affinity between these two elements. Furthermore, dark granules of HgSe were observed in Kupffer cells in the liver by electron microscopy, suggesting the role of this macrophage in the detoxification of Hg. A transfer of Hg through placenta was proved. The presence of Hg in brain in all age classes did not show concentrations associated with neurotoxicity. PMID:27210558

  9. Survival of the probiotic bacteria Lactobacillus rhamnosus in seawater and its bioencapsulation in the brine shrimp Artemia

    Directory of Open Access Journals (Sweden)

    Claudia Ofelio

    2014-06-01

    The results obtained in the first test showed that the L. rhamnosus was able to survive in seawater during the whole experiment (30h, maintaining densities of 10e7 CFU/ml during the first 6h although decreasing progressively afterwards (10e3 CFU/ml at 30h. This allows adequate levels at sufficient time for Artemia to incorporate the probiotic. In fact, bioencapsulation test demonstrated that Artemia metanauplii were able to bioencapsulate the probiotic, reaching the highest concentration in Artemia after 30 min of bioencapsulation (10e4 CFU/Artemia. A slight further decrease (10e3 CFU/Artemia was observed after 24h. Interestingly, L. rhamnosus reduced in 1Log total Vibrionaceae bacteria in Artemia during the 3 first hours. Therefore, 3 hours was the time established for the bioencapsulation protocol and further studies are in progress to determine the ability of Artemia metanauplii to maintain bioencapsulated L. rhamnosus once transferred to rearing tanks. Also, the capability of the probiotic to inhibit potential pathogenic or opportunistic bacteria will be assessed.

  10. Phylogenetic Analysis of Brine Shrimp (Artemia) in China Using DNA Barcoding

    Institute of Scientific and Technical Information of China (English)

    Weiwei Wang; Jun Yu; Qibin Luo; Haiyan Guo; Peter Bossier; Gilbert Van Stappen; Patrick Sorgeloos; Naihong Xin; Qishi Sun; Songnian Hu

    2008-01-01

    DNA barcoding is a powerful approach for characterizing species of organisms,especially those with almost identical morphological features, thereby helping to to establish phylogenetic relationships and reveal evolutionary histories. In this study, we chose a 648-bp segment of the mitochondrial gene, cytochrome c oxidase subunit 1 (COI), as a standard barcode region to establish phylogenetic relationships among brine shrimp (Artemia) species from major habitats around the world and further focused on the biodiversity of Artemia species in China, especially in the Tibetan Plateau. Samples from five major salt lakes of the Tibetan Plateau located at altitudes over 4,000 m showed clear differences from other Artemia populations in China. We also observed two consistent amino acid changes, 153A/V and 183L/F, in the COI gene between the high and low altitude species in China.Moreover, indels in the COI sequence were identified in cyst and adult samples unique to the Co Qen population from the Tibetan Plateau, demonstrating the need for additional investigations of the mitochondrial genome among Tibetan Artemia populations.

  11. Assessment of cyst production potential of a natural population of brine shrimp Artemia

    Digital Repository Service at National Institute of Oceanography (India)

    Royan, J.P.; Sumitra-Vijayaraghavan; Krishnakumari, L.

    Studies on a natural population of Artemia in the salterns of Jamnagar indicated that the population is parthenogenetic. These shrimps reach a maximum size of 9 mm. Number of cysts per brood varies from 10-32. Adults form about 68% of the total...

  12. Effect of artificial regulations of Artemia n-3 HUFA content on growth and survival of black seabream ( Sparus macrocephalus) larvae

    Science.gov (United States)

    Liu, Jing-Ke

    1998-06-01

    The requirement for dietary n-3 HUFA (highly unsaturated fatty acid) for growth and survival of black seabream ( Sparus macrocephalus) larvae was tested using Artemia with various levels of n-3 HUFA. Four treatments with Artemia differing in their n-3 HUFA were prepared by feeding them various oil emulsions. The results indicated that dietary n-3 HUFA significantly influences fish n-3 HUFA levels and are necessary for good growth and survival of black seabream larvae. The proper value of n-3 HUFA level and DHA, EPA level in Artemia should be 4.273% and 0.873% (wet weight) for good growth and survival in black seabream larvae respectively.

  13. The genus Artemia Leach, 1819 (Crustacea: Branchiopoda: I. True and false taxonomical descriptions El género Artemia Leach, 1819 (Crustacea: Branchiopoda: I. Descripciones taxonómicas verdaderas y falsas

    Directory of Open Access Journals (Sweden)

    Alireza Asem

    2010-01-01

    Full Text Available The brine shrimp Artemia is important for aquaculture since it is bighly nutritious. It is also used widely in biological studies because it is easy to culture. The aim of the present study is to review the literature on the taxonomical nomenclature of Artemia. The present study indicates the existence of seven species: three living in the Americas, one in Europe, and three in Asia.El camarón de salmuera Artemia es importante para la acuicultura por su alta calidad nutricional y es muy utilizado para estudios biológicos por ser de fácil cultivo. El objetivo del presente estudio es revisar la literatura sobre la nomenclatura taxonómica de Artemia. Se determina la existencia de siete especies; tres de ellas viven en América, una en Europa y tres en Asia.

  14. Reducing Vibrio load in Artemia nauplii using antimicrobial photodynamic therapy: a promising strategy to reduce antibiotic application in shrimp larviculture

    Digital Repository Service at National Institute of Oceanography (India)

    Aparna, A.; Arshad, E.; Jasmin, C.; Pai, S.S.; BrightSingh, I.S.; Mohandas, A.; Anas, A.

    be attributed to the destruction of outer membrane protein of V. harveyi by reactive oxygen intermediates produced during the photosensitization. Further, mesocosm experiments with V. harveyi and Artemia nauplii demonstrated that in 30 min, the aPDT could kill...

  15. Primary Screening of the Bioactivity of Brackishwater Cyanobacteria: Toxicity of Crude Extracts to Artemia salina Larvae and Paracentrotus lividus Embryos

    Directory of Open Access Journals (Sweden)

    Viviana R. Lopes

    2010-03-01

    Full Text Available Cyanobacteria are a diverse group of Gram-negative bacteria that produce an array of secondary compounds with selective bioactivity against vertebrates, invertebrates, plants, microalgae, fungi, bacteria, viruses and cell lines. The aim of this study was to assess the toxic effects of aqueous, methanolic and hexane crude extracts of benthic and picoplanktonic cyanobacteria isolated from estuarine environments, towards the nauplii of the brine shrimp Artemia salina and embryos of the sea urchin Paracentrotus lividus. The A. salina lethality test was used as a frontline screen and then complemented by the more specific sea urchin embryo-larval assay. Eighteen cyanobacterial isolates, belonging to the genera Cyanobium, Leptolyngbya, Microcoleus, Phormidium, Nodularia, Nostoc and Synechocystis, were tested. Aqueous extracts of cyanobacteria strains showed potent toxicity against A. salina, whereas in P. lividus, methanolic and aqueous extracts showed embryo toxicity, with clear effects on development during early stages. The results suggest that the brackishwater cyanobacteria are producers of bioactive compounds with toxicological effects that may interfere with the dynamics of invertebrate populations.

  16. USE OF BRINE SHRIMP (ARTEMIA IN THE FEEDING OF STURGEON JUVENILES (ACIPENSERIDAE (REVIEW

    Directory of Open Access Journals (Sweden)

    M. Simon

    2016-06-01

    Full Text Available Purpose. To review scientific sources on the technological and biological characteristics of the use of brine shrimp (Artemia in the feeding of sturgeon juvenilse (Acipenseridae. To highlight the common biotechnological bases of the enrichment of brine shrimp with biologically active substances necessary for the full development of sturgeon juveniles. Findings. The review of scientific papers showed that the technology is the use of brine shrimp in the feeding of sturgeon speices not only had not lost its relevance in aquaculture, but also continued to evolve in response to new challenges. The review contains a description of the peculiarities of the biological structure of brine shrimp eggs and methods of their quality assessment in the field. It describes the nutritional characteristics of Artemia. It is shown that brine shrimp is the best food organism for the use in the feeding of sturgeon fingerlings. The calculation scheme for Artemia decapsulation and incubation is provided. The main technological stages of of the preparation of shrimps before their use in feeding – activation, hydration, decapsulation, incubation, dehydration were described. The effect of brine shrimp nauplia enriched with biologically active substances enriched brine shrimp on sturgeon juveniles was highlighted. Practical value. Fish farm owners search for cost-effective, easy to use, and available food that is preferred by sturgeon juveniles (Acipenseridae. Brine shrimp nauplii obtained from cysts can be readil used to feed fish just after one-day incubation. Instar I (the nauplii that just hatched and contain large yolk reserves in their body and instar II nauplii (the nauplii after first moult and with functional digestive tracts are more widely used in aquaculture, because they are easy for operation, rich in nutrients, and small, which makes them suitable for feeding fish larvae as live feed or after drying. The generalized information will be important for

  17. Evolutionary Origin and Phylogeography of the Diploid Obligate Parthenogen Artemia parthenogenetica (Branchiopoda: Anostraca)

    DEFF Research Database (Denmark)

    Muñoz, Joaquin; Gómez, Africa; Green, Andy J.;

    2010-01-01

    Background: Understanding the evolutionary origin and the phylogeographic patterns of asexual taxa can shed light on the origin and maintenance of sexual reproduction. We assessed the geographic origin, genetic diversity, and phylogeographic history of obligate parthenogen diploid Artemia...... and recent evolutionary origin of diploid A. parthenogenetica, and strongly suggested that the geographic origin of parthenogenesis in Artemia was in Central Asia. Our results indicate that the maternal sexual ancestors of diploid A. parthenogenetica were an undescribed species from Kazakhstan and A. urmiana....... Conclusions/Significance: We found evidence for multiple origin of parthenogenesis in Central Asia. Our results indicated that, shortly after its origin, diploid A. parthenogenetica populations underwent a rapid range expansion from Central Asia towards the Mediterranean region, and probably to the rest...

  18. Participation of metanauplii and juvenile individuals of Artemia parthenogenetica (Branchiopoda) in the circulation of avian cestodes.

    Science.gov (United States)

    Redón, Stella; Amat, Francisco; Hontoria, Francisco; Vasileva, Gergana P; Nikolov, Pavel N; Georgiev, Boyko B

    2011-04-01

    Adult crustaceans of the genus Artemia (brine shrimps) are intermediate hosts in the life cycle of cestode species parasitic in aquatic birds as their definitive hosts. However, there are no data on the role of larval and juvenile brine shrimps in the transmission of avian helminth parasites. In order to examine the possible role of early developmental stages (nauplii, metanauplii and juveniles) of Artemia for the circulation of avian cestodes, the natural cestode infection in the population of Artemia parthenogenetica from La Mata Lagoon, Mediterranean coast of Spain, was studied. Metacestodes (cysticercoids) of four cestode species were recorded in adult brine shrimps: Flamingolepis liguloides and Flamingolepis flamingo (hymenolepidids parasitic in flamingos), Confluaria podicipina (a hymenolepidid species parasitic in grebes) and Eurycestus avoceti (a dilepidid species parasitic in avocets, stilts, plovers and, to a lesser extent, in flamingos). No cysticercoids were found in nauplii. Two species, F. liguloides and F. flamingo, were found in metanauplii and juvenile brine shrimps. Only 36.3% of the cysticercoids of F. liguloides occurred in adult brine shrimps; the remaining 63.7% were parasitic in metanauplii (39.6%) and juveniles (24.1%). Similarly, the metacestodes of F. flamingo were also distributed among various age groups: in adults (44.4% of cysticercoids), juveniles (27.8%) and metanauplii (27.8%). These results indicate that the early developmental stages of Artemia have an important role for the circulation of certain parasite species. No cysticercoids of C. podicipina and E. avoceti were recorded in larval and juvenile brine shrimps. The selective infestation of larval brine shrimps with flamingo parasites is probably associated with the feeding behaviour of definitive hosts, which are filtering predators; in contrast, grebes and waders pick brine shrimps individually one by one. The possible underlying mechanism for selective infestation of

  19. Morphological changes about Artemia Salina by the effect of gamma radiation

    International Nuclear Information System (INIS)

    Direction Council of Europe require restriction of laboratory vertebrae in biological experiments. Once by possibilities is using biological test II. generation among which belongs to and test for Artemia salina. Still this time published test however value only lethality in dependence on dose, exposition and time survival. This work document possibility watch of expressive morphological changes, which consist in retardation development brine shrimps stage in dependence on dose gamma radiation 60Co. (authors)

  20. Vaccination of European sea bass fry through bioencapsulation of Artemia nauplii

    OpenAIRE

    Chair, M.; Gapasin, R.S.J.; Dehasque, M.; Sorgeloos, P.

    1994-01-01

    European sea bass (Dicentrarchus labrax) fry vaccinated orally by bioencapsulation in Artemia nauplii or by bath method exhibited better performance than control fish in terms of growth, food conversion and resistance to stress. The comparable survival between vaccinated and non-vaccinated animals suggests that vaccination methods are stressful. The present study shows that oral vaccination can be used to enhance growth in fish fry.

  1. Biological screening of selected Pacific Northwest forest plants using the brine shrimp (Artemia salina) toxicity bioassay.

    Science.gov (United States)

    Karchesy, Yvette M; Kelsey, Rick G; Constantine, George; Karchesy, Joseph J

    2016-01-01

    The brine shrimp (Artemia salina) bioassay was used to screen 211 methanol extracts from 128 species of Pacific Northwest plants in search of general cytotoxic activity. Strong toxicity (LC50  1000 µg/ml). Our subsequent studies of conifer heartwoods with strong activity confirm the assay's value for identifying new investigational leads for materials with insecticidal and fungicidal activity. PMID:27186474

  2. Da praça ao pergaminho: Os Sermones In circulum anni de Sovramonte de Varese, Omin, na Lombardia Franciscana

    Directory of Open Access Journals (Sweden)

    Eleonora Lombardo

    2015-04-01

    Full Text Available Este artigo apresenta uma pequena e quase ignorada coleção de sermões oriundos da Itália setentrional. Eles foram escritos por um frade franciscano chamado Sovramonte de Varese (Supermons de Varisio, por volta da metade do século XIII. Tais sermões são úteis para entender as dinâmicas entre a apresentação oral do sermão e a sua escrita. Após uma detalhada reconstrução da biografia de Sovramonte, o artigo apresenta a coleção priorizando dois temas: a usura e a heresia. Ambos permitem-nos recuperar a ação do frade no contexto urbano supostamente de Milão. Tentar-se-à introduzir a questão das relações desta coleção com obras contemporâneas, como os sermões de Felipe o Chanceler e Santo Antônio de Pádua, para esclarecer as passagens que aparecem subentendidas em todo o trabalho de Sovramonte: a leitura, a pregação e a escrita. Palavras-chave - Supermons de Varisio, sermões medievais, pregação, ordem franciscana, usura, heresia.

  3. Neuroanatomical clues to peripheral locomotor control in small crustaceans (Artemia salina).

    Science.gov (United States)

    Kane, E S

    1975-08-01

    Brine shrimp (Artemia salina) were prepared for light and electron microscopy at several stages. Immersion-fixed, rapid Golgi impregnations demonstrated two distinct neuronal types in thoracic appendages of mature, freely swimming Artemia. Isolated motor neurons had large cell somas and thick, radiating dendrites at the body wall-limb junction. A long, elaborate axon extended into the limb. Groups of a second type of neuron with smaller somas and very thin, radiating processes occurred in the distal limb near presumably tactile bristles. Thick axons from motor neurons were traced to terminals associated with limb muscle. Both muscle and axon were best seen with Nomarski optics. Motor axons possessed elongate, irregularly shaped boutons en passant and morphologically variable boutons terminaux; the latter included huge endings with knobbed projectiles arising from thick collaterals, or smaller, round boutons from thin collaterals. In addition, a thick unidentified axon coursed longitudinally within the central body wall, sending short collaterals peripherally. The elaborate peripheral neurons described in this Golgi study may be anatomical correlates for the extraordinary coordination of mature brine shrimp. Because Artemia movements resemble those of leech and decapods, which have been studied extensively electrophysiologically, the possibility of similarly elaborate peripheral structures supplementing central control of locomotion in those invertebrates should be considered.

  4. Laboratory generation of new parthenogenetic lineages supports contagious parthenogenesis in Artemia

    Directory of Open Access Journals (Sweden)

    Marta Maccari

    2014-06-01

    Full Text Available Contagious parthenogenesis—a process involving rare functional males produced by a parthenogenetic lineage which mate with coexisting sexual females resulting in fertile parthenogenetic offspring—is one of the most striking mechanisms responsible for the generation of new parthenogenetic lineages. Populations of the parthenogenetic diploid brine shrimp Artemia produce fully functional males in low proportions. The evolutionary role of these so-called Artemia rare males is, however, unknown. Here we investigate whether new parthenogenetic clones could be obtained in the laboratory by mating these rare males with sexual females. We assessed the survival and sex ratio of the hybrid ovoviviparous offspring from previous crosses between rare males and females from all Asiatic sexual species, carried out cross-mating experiments between F1 hybrid individuals to assess their fertility, and estimated the viability and the reproductive mode of the resulting F2 offspring. Molecular analysis confirmed the parentage of hybrid parthenogenetic F2. Our study documents the first laboratory synthesis of new parthenogenetic lineages in Artemia and supports a model for the contagious spread of parthenogenesis. Our results suggest recessive inheritance but further experiments are required to confirm the likelihood of the contagious parthenogenesis model.

  5. Assessment of toxic potential of Cerrado fruit seeds using Artemia salina bioassay

    Directory of Open Access Journals (Sweden)

    Raíza Cavalcante Fonseca

    2013-06-01

    Full Text Available Artemia salina bioassay was used to assess toxicity of seeds and kernels of Brazilian fruits from cerrado (central high plains region and other inner regions of the country. Water extracts of the kernels were filtered and added to Artemia cultures containing ten individuals per mL. Dose - response curves were constructed, and LD50 values were calculated. Pure potassium cyanide standard was used to draw a calibration curve for comparison to detect the presence of cyanide in the samples tested. Extracts of the seeds of araticum, mangaba, cagaita, jatobá, and tucumã were found toxic to Artemia salina, and some of the dose - response curves were very similar in shape to those obtained with pure potassium cyanide standards, while the samples of baru, cajá-manga, siriguela, trauma, and veludo showed no toxicity at all. The Guignard test, specific for cyanide detection, showed negative results in all toxic samples, suggesting the presence of other toxic compounds rather than cyanide. The comparison of araticum dose - response curve with those of other annonaceous fruits suggests the presence acetogenins as the main toxic compounds in the seeds. These results could be useful to prevent poisoning by industrial derivatives of the fruits studied.

  6. 用卤虫(Artemia salina L.)评价杀虫活性%Evaluate Insecticidal Activity Using Artemia salina L.

    Institute of Scientific and Technical Information of China (English)

    王再强; 周红; 韩俊; 何月秋; 录丽平

    2011-01-01

    [Aims]Artemia salina L.is general used for preliminary assessment of pharmacological activity.However,it is necessary to evaluate the suitability of A.salina L.before it is used as a model material for screening insecticidal activity.Here, 14 insecticides with 10 different action mechanisms were selected to evaluate insecticidal activity against A.salina L.used as a model material.[Results]13 Insecticides significantly killed A.salina L., Moulting hormone agonist and compound stimulating GABA release were the most active.[Conclusions]A.salina L.is a suitable organism to evaluate insecticidal activity and the method is simple having good sensitivity to many insecticides with different action mechanisms.%[目的]以卤虫(Artemia salina L.)为模式生物对化合物的药理活性进行初步评价.对10种不同作用机制的14种杀虫剂进行了生物筛选试验.[结果]14种供试杀虫剂中有13种对卤虫有显著的毒杀效果,作用于以γ-氨基丁酸为神经递质传导系统的化合物及蜕皮激素类似物效果最为显著.[结论]用卤虫筛选杀虫剂活性的方法简便,对多种作用机制的杀虫剂灵敏.

  7. Evolutionary origin and phylogeography of the diploid obligate parthenogen Artemia parthenogenetica (Branchiopoda: Anostraca.

    Directory of Open Access Journals (Sweden)

    Joaquín Muñoz

    Full Text Available BACKGROUND: Understanding the evolutionary origin and the phylogeographic patterns of asexual taxa can shed light on the origin and maintenance of sexual reproduction. We assessed the geographic origin, genetic diversity, and phylogeographic history of obligate parthenogen diploid Artemia parthenogenetica populations, a widespread halophilic crustacean. METHODOLOGY/PRINCIPAL FINDINGS: We analysed a partial sequence of the Cytochrome c Oxidase Subunit I mitochondrial gene from an extensive set of localities (including Eurasia, Africa, and Australia, and examined their phylogeographic patterns and the phylogenetic relationships of diploid A. parthenogenetica and its closest sexual relatives. Populations displayed an extremely low level of mitochondrial genetic diversity, with one widespread haplotype shared by over 79% of individuals analysed. Phylogenetic and phylogeographic analyses indicated a multiple and recent evolutionary origin of diploid A. parthenogenetica, and strongly suggested that the geographic origin of parthenogenesis in Artemia was in Central Asia. Our results indicate that the maternal sexual ancestors of diploid A. parthenogenetica were an undescribed species from Kazakhstan and A. urmiana. CONCLUSIONS/SIGNIFICANCE: We found evidence for multiple origin of parthenogenesis in Central Asia. Our results indicated that, shortly after its origin, diploid A. parthenogenetica populations underwent a rapid range expansion from Central Asia towards the Mediterranean region, and probably to the rest of its current geographic distribution. This contrasts with the restricted geographic distribution, strong genetic structure, and regional endemism of sexual Artemia lineages and other passively dispersed sexual continental aquatic invertebrates. We hypothesize that diploid parthenogens might have reached their current distribution in historical times, with a range expansion possibly facilitated by an increased availability of suitable

  8. Toxicity of Five Phenolic Compounds to Brine Shrimp Artemia sinica(Crustacea:Artemiidae)

    Institute of Scientific and Technical Information of China (English)

    Ali Shaukat; LIU Guangxing; LI Zhengyan; XU Donghui; HUANG Yousong; CHEN Hongju

    2014-01-01

    The acute toxicity of five phenolic compounds each to 15 d old Artemia sinica was determined in this study. The brine shrimp A. sinica was hatched from the encysted dry eggs (Bohai Bay Brand) produced by Dongying Ocean Artemia Co., Ltd., China at 27℃± 1℃in pre-filtered (through pores of 0.45 µm in diameter) and autoclaved seawater (salinity 31, pH 7.5-8.0) in a cilindroconical glass beaker (2000 mL in volume) under continuous illumination (provided by a side set 20 W fluorescent lamp) with slight aeration. Ten Artemia individuals from the same batch of the hatched were cultured in 10 mL toxicant solution prepared with seawater (salinity 31, pH 7.5-8.0) at room temperature (about 20℃) to determine 24 h, 48 h and 72 h medium lethal concentration (LC50) of 5 phenolic compounds each. It was found that the toxicity of n-heptylphenol was the highest followed by nonylphenol, t-butylphenol, 2,4-dichlorophenol and bisphenol A in order. The LC50 values of the 5 compounds were calculated with regression analysis. The real concentration (in µg L-1) of 5 phenolic compounds each in toxicant solutions was measured with GC/MS analysis. Significant loss of phenolic compounds caused by either adsorption or desorption was not found. The significant difference of LC50 values was found among the five compounds 3 exposure times each. The range between the highest no-observed-effect concentration (NOEC) and 100%death causing concentration of five phenolic compounds each was determined. The toxicity in term of 24 h LC50 value of n-HP was 9.10 times higher than that of BPA, 1.71 times higher than t-BP, 1.53 times higher than 2,4-DCP and 1.36 times higher than NP, respectively.

  9. Monitoramento dos extratos brutos de espécies de Polygala (Polygalaceae utilizando Artemia salina

    Directory of Open Access Journals (Sweden)

    A.B.P. Montanher

    2003-01-01

    Full Text Available Extratos de duas espécies de Polygala foram submetidos a um biomonitoramento utilizando o teste de toxicidade frente a Artemia salina, com a finalidade de detectar atividade citotóxica. Os resultados obtidos para o extrato bruto, frações hexânica e diclorometano de Polygala sabulosa Aw. Benn. mostraram-se promissores. No entanto, bioensaios mais específicos devem ser encorajados nos extratos vegetais que apresentam atividade diante deste bioensaio, a fim de confirmar estas conclusões.

  10. The brine shrimp ( Artemia parthenogenetica) as encapsulation organism for prophylactic chemotherapy of fish and prawn

    Science.gov (United States)

    Cao, Ji-Xiang; Bian, Bo-Zhong; Li, Ming-Ren

    1996-06-01

    Brine shrimp ( Artemia parthenogenetica) which had ingested three water-insoluble antibacterial drugs i.e. sulfadiazine(SD), oxytetracycline (OTC) and erythromycin estolate (ERY-Es) were fed to Tilapia and Mysis III of Penaeus orientalis K. The drug contents in the predators were then determined. After administration of drugs to Tilapia and Mysis III, through the bio-encapsulation of the brine shrimp, efficacious therapeutical concentration of OTC and ERY-Es (but not SD) in the predators could be reached and maintained for more than 8 hours.

  11. Quaternary structure of Artemia haemoglobin II: analysis of T and C polymer alignment and interpolymer interface

    Directory of Open Access Journals (Sweden)

    Rawle Vincent L

    2007-04-01

    Full Text Available Abstract Background The brine shrimp Artemia expresses four different types of haemoglobin subunits namely C1, C2, T1 and T2. Two of these four subunits dimerize in different combinations to produce the three isoforms of the heterodimeric Artemia haemoglobin: HbI (C1 and C2, HbII (C1 and T2 and HbIII (T1 and T2. Previous biochemical, biophysical and computational analyses demonstrate that the T and C polymers are rings of nine concatenated globin domains, which are covalently joined by interdomain linkers. Two such rings stacked coaxially give the functional molecule. This research aimed to construct a quaternary structural model of Artemia HbII that shows the interpolymer interface and domain-domain alignment, using the MS3D (mass spectrometry for three dimensional analysis approach. This involved introducing chemical crosslinks between the two polymers, cleaving with trypsin and analyzing the resulting products by mass spectrometry. This was followed by computational analysis of the mass spectrometry data using the program SearchXlinks to identify putatively crosslinked peptides. Results Six putative EGS (ethylene glycol bis [succinimidylsuccinate] crosslinked tryptic peptides were identified. All of them support a model in which the EF helices of all domains are in contact along the interpolymer surface, and Domain 1 of the T-polymer aligns with Domain 1 of the C-polymer. Any two adjacent interpolymer domain pairs contact through the early Helix H and early Helix A. The orientation of domains is different from the subunit proposed model proposed previously by this group. Crosslinking with GMBS (N- [γ-maleimidobutyryloxy]succinimide ester was also performed, and the results show good agreement with this model. Conclusion The interpolymer EF-contact allows the hydrophobic E and F helices to be buried in the interface and therefore allow the complex to solubilize readily to facilitate efficient oxygen transport. Furthermore the EF-contact is a

  12. Live preys in shrimp culture: nutritional and sanitary considerations on the use of Artemia in New Caledonia

    OpenAIRE

    Pham, Dominique; Wabete, Nelly; Maillez, Jean-rene; Broutoi, Francis; Chim, Liet

    2009-01-01

    In aquaculture, Artemia nauplii are commonly used as live prey; and represent 40 % of the total aquaculture feed demands in the early stages. However, the production of Brine shrimp is very unstable from one year to another and in the late 90’s, only 20 % of the world aquaculture need was covered. An insufficient offer leads to higher prices of the Artemia cysts and consequently, the price of shrimp juveniles from hatchery. In New Caledonia, marine aquaculture is mainly based on the blue s...

  13. Evaluation of the toxicity of the methanolic extract of Caesalpinia Pyramidalis, subjected to gamma radiation, compared to saline artemias; Avaliacao da toxicidade do extrato metanolico de Caesalpinia Pyramidalis, submetido a radiacao gama, frente a artemias salinas

    Energy Technology Data Exchange (ETDEWEB)

    Pessoa, Juanna G.; Santos, Mariana L.O.; Costa, Michelle C.A.; Siqueira, Williams N.; Silva, Luanna R.S.; Cabral, Daniela L.V.; Amancio, Francisco F.; Melo, Ana M.M.A., E-mail: marianasantos_ufpe@hotmail.com [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil)

    2013-07-01

    The present study aimed to investigate the possible effect of irradiation of 60 Co in methanol extract of Caesalpinia pyramidalis (catingueira) with function of reducing the toxicity of the extract at concentrations of 1000, 500, 250 and 125 ppm irradiating them with doses of 5 kGy 7 kGy and 10 kGy, using lethality tests with saline Artemias.

  14. Cloning and Expression Analysis of p26 Gene in Artemia sinica

    Institute of Scientific and Technical Information of China (English)

    Lijuan JIANG; Lin HOU; Xiangyang ZOU; Ruifeng ZHANG; Jiaqing WANG; Wenjing SUN; Xintao ZHAO; Jialu AN

    2007-01-01

    The protein p26 is a small heat shock protein that functions as a molecular chaperone to protect embryos by preventing irreversible protein damage during embryonic development. A 542 bp fragment of the p26 gene was cloned and sequenced. The fragment encoded 174 amino acid residues and the amino acid sequence contained the α-crystallin domain. Phylogenetic analysis showed that eight Artemia populations were divided into four major groups. Artemia sinica (YC) belonged to the East Asia bisexual group. Expression of the p26 gene at different developmental stages of A. sinica was quantified using real-time quantitative polymerase chain reaction followed by cloning and sequencing. The relationship between the quantity of p26 gene expression and embryonic development was analyzed. The results indicated that massive amounts of p26 were expressed during the development of A. sinica. At the developmental stage of 0 h, A. sinica expressed the highest level of p26. As development proceeded, expression levels of the p26 gene reduced significantly. There was a small quantity of p26 gene expression at the developmental stages of 16 h and 24 h. We concluded that p26 might be involved in protecting the embryo from physiological stress during embryonic development.

  15. Intentional introduction of Artemia sinica (Anostraca) in the high-altitude Tibetan lake Dangxiong Co: the new population and consequences for the environment and for humans

    Science.gov (United States)

    Jia, Qinxian; Anufriieva, Elena; Liu, Xifang; Kong, Fanjing; Shadrin, Nickolai

    2015-11-01

    The imbalance between supply and demand of Artemia cysts in China and around the world is increasing now. Salt lakes in Tibet may contribute to the solution of the problem. In Northern Tibet there are 26 saline lakes whose salinity and temperature may support Artemia survival at an altitude of 4 000-5 100 m. We found Artemia in 15 of these lakes. The saline lakes with Artemia populations mainly belong to the shallow basin lakes, and the majority of these lakes are small in area. The total area of lakes without Artemia is more than 1 000 km2. Lake Dangxiong Co (Co means lake in Tibet) was chosen for the intentional introduction of Artemia sinica. In 2004, 850 g of A. sinica cysts, originating from Qinghai, were introduced in the lake. Surveys in 2006-2014 showed that the average abundance of Artemia adults in the lake gradually increased from 20 ind./m3 in 2006 to 1950 ind./m3 in 2013. We assume that two subpopulations of A. sinica, separated by depth, may exist in the lake. The new Artemia population caused an increase in the number of species of phytoplankton and heterotrophic protozoa with a decrease of their total abundance. Water transparency also increased. Dominance in phytoplankton passed from cyanobacteria to diatoms. Changes occurred not only in the lake ecosystem; the number of water birds using the lakes also dramatically increased. Preliminary calculations showed that is it possible to harvest at least about 150 t cysts per year from the lake as well as 3.2 thousand tons of frozen or 350 t of dried biomass of adult Artemia.

  16. Nutrient enrichment of Artemia with free methionine%蛋氨酸对卤虫营养强化

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    Methionine is indispensable of an essential amino acid for fish growing development , Artemia nauplii is commonly used as the start feed on fish larvae stage. But Artemia in vivo amino acid imbalance, especially methionine deficiency can not meet the nutritional needs of nutrition. Methionine is of great importance to nutrient enrichment of Artemia. Methionine is a common nutritional fortifier . This paper mainly introduces the purpose, methods and results of nutrient enrichment, and discuss the impact of enrichment of Artemia with free methionine.%  蛋氨酸是鱼类生长发育不可缺少的必需氨基酸,仔稚鱼时期常常用卤虫作为仔稚鱼的开口饵料,但卤虫的体内的氨基酸不平衡,尤其是蛋氨酸缺乏难以满足仔稚鱼的营养需求,因此蛋氨酸对卤虫的营养强化有很重要的意义。蛋氨酸是常用的营养强化剂,文章综述了蛋氨酸强化的目的、方法和结果,并讨论了影响蛋氨酸营养强化的因素。

  17. Post-prandial protease activity in the digestive tract of African catfish, Clarias gariepinus, larvae fed decapsulated cysts of Artemia

    NARCIS (Netherlands)

    García Ortega, A.; Verreth, J.; Segner, H.

    2000-01-01

    The alkaline proteolytic activity in the gut of African catfish larvae was studied during short time ranges from 30 min to 4 h after ingestion of decapsulated Artemia cysts. The variation in total protease and trypsin activities during the day was monitored during starvation, after one single meal i

  18. Sudden weaning of angel fish pterophyllum scalare (Lichtenstein) (Pisces; Cichlidae) larvae from brine shrimp (Artemia sp) nauplii to formulated larval feed

    OpenAIRE

    Herath, Sandamali Sakunthala; Atapaththu, Kerthi Sri Senarathna

    2013-01-01

    This study investigated the effects of sudden weaning of angel fish larvae (Pteraphylum scalari) from Artemia nauplii to commercial larval feed. Four days post hatch (DPH) larvae were reared in four different weaning protocols (TR1-TR4) with triplicates in a complete randomize design. Larvae in TR1 and TR4 were exclusively fed Artemia nauplii and dry feed respectively. In TR2 and TR3, larvae were initially fed Artemia nauplii and suddenly wean to formulated feed on 14 DPH and 7 DPH respective...

  19. Cytotoxicity of antimalarial plant extracts from Kenyan biodiversity to the brine shrimp, Artemia salina L. (Artemiidae

    Directory of Open Access Journals (Sweden)

    Joseph Mwanzia Nguta

    2012-07-01

    Full Text Available Artemia salina (Artemiidae, the brine shrimp larva, is an invertebrate used in the alternative test to determine toxicity of chemicals and natural products. In this study the medium lethal concentration fifty (LC50 values of 45 antimalarial plant extracts and positive controls, cyclophosphamide and etoposide were determined using Artemia salina (Artemiidae. Out of the 45 organic extracts screened for activity against Artemia salina larvae, 23 (51% of the crude extracts demonstrated activity at or below 100 μg/mL, and were categorized as having strong cytotoxic activity, 18 (40% of the crude extracts had LC50 values between 100 μg/mL and 500 μg/mL, and were categorized as having moderate cytotoxicity, 2 (4.5% of the crude extracts had LC50 values between 500 μg/mL and 1000 μg/mL, and were considered to have weak cytotoxic activity, while 2 (4.5% of the crude extracts had LC50 values greater than 1000 μg/mL and were considered to be non toxic. Approximately 20% (9 of the aqueous extracts demonstrated activity at or below 100 g/mL and were considered to have strong cytotoxic activity, 40% (18 of the screened aqueous crude extracts had LC50 values between 100 μg/mL and 500 μg/mL and were considered to be moderately cytotoxic, 16% (7 of the crude extracts had LC50 values between 500 μg/mL and 1000 μg/mL and were considered to have weak cytotoxic activity while 24% (11 of the aqueous extracts had LC50 values greater than 1000μg/mL and were categorized as non toxic The positive controls, cyclophosphamide and etoposide exhibited strong cytotoxicity with LC50 values of 95 μg/mL and 6 μg/mL respectively in a 24 hour lethality study, validating their use as anticancer agents. In the current study, 95.5% of all the screened organic extracts and 76% of the investigated aqueous extracts demonstrated LC50 values <1000 g/mL, indicating that these plants could not make safe anti-malarial treatments. This calls for dose adjustment amongst the

  20. Genetic variation in parthenogenetic Artemia from the Shandong Peninsula, P.R.C.

    Science.gov (United States)

    King, Charles E.; Zhao, Yuqi; Liu, Xin; Li, Mingren

    1988-06-01

    Results are presented of a survey of isozyme frequencies in parthenogenetic Artimia from six salterns in the Shandong Peninsula, P.R.C. Three of the eleven enzymes we scored using polyacryamide gel electrophoresis proved to be useful for analysis of electromorph frequency variation. These enzymes are tetrazolium oxidase (TO), lactate dehydrogenase (LDH), and malate dehydrogenase (MDH). Each of these systems showed extensive isozyme variation both within and between salterns. In addition, we have examined the possibility that electromorph frequencies may vary as the result of natural selection for adaptation to specific salinity, or salinity-associated environmental conditions. An indication of clinal variation was found in two series of ponds differing in salinity, however more extensive data are needed before it is possible to conclude that these patterns are the result of natural selection. Finally, the use of isozyme analyses such as ours, for unraveling taxonomic problems in Artemia is discussed.

  1. First secondary metabolites from Herissantia crispa L (Brizicky and the toxicity activity against Artemia salina Leach

    Directory of Open Access Journals (Sweden)

    Danielly Albuquerque da Costa

    2009-01-01

    Full Text Available The phytochemical investigation of Herissantia crispa led to the isolation of seven compounds, identified as: sitosterol 3-O-β-D-glucopyranoside, stigmasterol 3-O-β-D-glucopyranoside, 3,5,7,4'-tetrahydroxyflavone (kaempferol, 3,5,7,3',4'-pentahydroxyflavone (quercetin, unpublished in the genus Herissantia, besides β-sitosterol, kaempferol 3-O-β-D-(6''-E-p-coumaroil (tiliroside glucopyranoside and kaempferol 3,7-di-O-α-L-ramnopyranoside (lespedin, described for the first time in the species. The structural determination of the compounds was made by means of spectroscopy methods such as Infrared Spectroscopy, ¹H and 13C Nuclear Magnetic Resonance, with the aid of two dimensional techniques, and by comparison with literature data. The toxicity activity of the MeOH extract and lespedin on Artemia salina Leach. was also carried out.

  2. IDENTIFIKASI DAN UJI AKTIVITAS ANTIKANKER EKSTRAK SPONS Ianthella basta TERHADAP LARVA Artemia salina L.

    Directory of Open Access Journals (Sweden)

    Ni Wayan Sri Sukmarianti

    2013-05-01

    Full Text Available The main purpose of this research is to determine the toxicity of extracts sponge Ianthella basta against Artemia salina larvae and to identify the chemical compounds contained in those toxic isolates. The preliminary test of the anticancer activity has conducted by Brine Shrimp Letalithy (BST test. The results showed that the chloroform extract was the most toxic with LC50 value of 22,39 ppm. Futher, the cloroform extract was separated and purified by coloumn chromatography using eluent of solvent mixture of chloroform : ethyl acetate : n-hexane by 7 : 2 : 1 and 4 fractions were obtained. The most toxic fraction was the fraction C with LC50 value of 35,36 ppm. Based on the GC-MS results, the toxic isolate is allegedly containing chemicals compound of hexadecanoic methyl ester and hexadecanoic acid.

  3. First secondary metabolites from Herissantia crispa L (Brizicky) and the toxicity activity against Artemia salina Leach

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Danielly Albuquerque da; Matias, Wemerson Neves; Lima, Igara Oliveira; Xavier, Aline Lira; Costa, Vivian Bruna Machado; Diniz, Margareth de Fatima Formiga Melo; Agra, Maria de Fatima; Batista, Leonia Maria; Souza, Maria de Fatima Vanderlei de [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Lab. de Tecnologia Farmaceutica Prof. Delby Fernandes de Medeiros; Silva, Davi Antas e [Universidade Federal Rural de Pernambuco, Serra Talhada, PE (Brazil). Dept. de Quimica

    2009-07-01

    The phytochemical investigation of Herissantia crispa led to the isolation of seven compounds, identified as: sitosterol 3-O-{beta}-D-glucopyranoside, stigmasterol 3-O-{beta}-D-glucopyranoside, 3,5,7,4'-tetrahydroxyflavone (kaempferol), 3,5,7,3',4'-pentahydroxyflavone (quercetin), unpublished in the genus Herissantia, besides {beta}-sitosterol, kaempferol 3-O-{beta}-D-(6''-E-p-coumaroil) (tiliroside) glucopyranoside and kaempferol 3,7-di-O-{alpha}-L-ramnopyranoside (lespedin), described for the first time in the species. The structural determination of the compounds was made by means of spectroscopy methods such as Infrared Spectroscopy, {sup 1}H and {sup 13}C Nuclear Magnetic Resonance, with the aid of two dimensional techniques, and by comparison with literature data. The toxicity activity of the MeOH extract and lespedin on Artemia salina Leach. was also carried out. (author)

  4. Involvement of cyclin K posttranscriptional regulation in the formation of Artemia diapause cysts.

    Directory of Open Access Journals (Sweden)

    Yang Zhao

    Full Text Available BACKGROUND: Artemia eggs tend to develop ovoviviparously to yield nauplius larvae in good rearing conditions; while under adverse situations, they tend to develop oviparously and encysted diapause embryos are formed instead. However, the intrinsic mechanisms regulating this process are not well understood. PRINCIPAL FINDING: This study has characterized the function of cyclin K, a regulatory subunit of the positive transcription elongation factor b (P-TEFb in the two different developmental pathways of Artemia. In the diapause-destined embryo, Western blots showed that the cyclin K protein was down-regulated as the embryo entered dormancy and reverted to relatively high levels of expression once development resumed, consistent with the fluctuations in phosphorylation of position 2 serines (Ser2 in the C-terminal domain (CTD of the largest subunit (Rpb1 of RNA polymerase II (RNAP II. Interestingly, the cyclin K transcript levels remained constant during this process. In vitro translation data indicated that the template activity of cyclin K mRNA stored in the postdiapause cyst was repressed. In addition, in vivo knockdown of cyclin K in developing embryos by RNA interference eliminated phosphorylation of the CTD Ser2 of RNAP II and induced apoptosis by inhibiting the extracellular signal-regulated kinase (ERK survival signaling pathway. CONCLUSIONS/SIGNIFICANCE: Taken together, these findings reveal a role for cyclin K in regulating RNAP II activity during diapause embryo development, which involves the post-transcriptional regulation of cyclin K. In addition, a further role was identified for cyclin K in regulating the control of cell survival during embryogenesis through ERK signaling pathways.

  5. Intracellular water in Artemia cysts (brine shrimp): Investigations by deuterium and oxygen-17 nuclear magnetic resonance.

    Science.gov (United States)

    Kasturi, S R; Seitz, P K; Chang, D C; Hazlewood, C F

    1990-08-01

    The dormant cysts of Artemia undergo cycles of hydration-dehydration without losing viability. Therefore, Artemia cysts serve as an excellent intact cellular system for studying the dynamics of water-protein interactions as a function of hydration. Deuterium spin-lattice (T(1)) and spin-spin (T(2)) relaxation times of water in cysts hydrated with D(2)O have been measured for hydrations between 1.5 and 0.1 g of D(2)O per gram of dry solids. When the relaxation rates (I/T(1), I/T(2)) of (2)H and (17)O are plotted as a function of the reciprocal of hydration (1/H), an abrupt change in slope is observed near 0.6 g of D(2)O (or H(2) (17)O)/gram of dry solids, the hydration at which conventional metabolism is activated in this system. The results have been discussed in terms of the two-site and multisite exchange models for the water-protein interaction as well as protein dynamics models. The (2)H and (17)O relaxation rates as a function of hydration show striking similarities to those observed for anisotropic motion of water molecules in protein crystals.It is suggested here that although the simple two-site exchange model or n-site exchange model could be used to explain our data at high hydration levels, such models are not adequate at low hydration levels (<0.6 g H(2)O/g) where several complex interactions between water and proteins play a predominant role in the relaxation of water nuclei. We further suggest that the abrupt change in the slope of I/T(1) as a function of hydration in the vicinity of 0.6 g H(2)O/g is due to a change in water-protein interactions resulting from a variation in the dynamics of protein motion. PMID:19431762

  6. Uji Sitotoksik Fraksi Etilasetat Daun Bangun-Bangun (Plectranthus amboinicus (Lour.) terhadap Larva Artemia salina Leach dengan Metode Brine Shrimp Lethality Test (BSLT)

    OpenAIRE

    Pardede, E. Roslina

    2016-01-01

    Background: Bangun-Bangun leaves (Plectranthus amboinicus (Lour.) Spreng is one of the plants that have the potential to be developed as a cancer chemopreventive agent. The Purpose: The aim of the study were to find out the cytotoxic effect of ethylacetate fraction bangun-bangun leaves (FEDBB) on Artemia salina Leach larvae. Methods: This experimental study using 800 Artemia salina Leach larvae were divided into one control group negative 1 and 5 positive control group concentration10 μ...

  7. Prospecção fitoquímica de Sonchus oleraceus e sua toxicidade sobre o microcrustáceo Artemia salina Phytochemical prospecting of Sonchus oleraceus and its toxicity to Artemia salina

    Directory of Open Access Journals (Sweden)

    J.M. Lima

    2009-03-01

    Full Text Available A espécie vegetal Sonchus oleraceus é uma planta daninha presente em diversas culturas no Brasil e de utilização na medicina popular. Neste trabalho, realizou-se a prospecção fitoquímica dessa espécie com extratos em etanol, água e diclorometano, bem como testes de toxicidade sobre o microcrustáceo Artemia salina. O extrato aquoso apresentou em sua composição açúcares redutores, compostos fenólicos, taninos, flavonóides e cumarinas. No extrato etanólico, observaram-se os mesmos compostos qualificados no extrato aquoso, com exceção de cumarinas. Em diclorometano, verificou se a presença de saponinas, derivados triterpênicos e esteróides. No teste de toxicidade sobre Artemia salina, os dados convergiram para frações de extrato aquoso de 5.117,2 ppm, indicando ser um extrato de baixa toxicidade.Sonchus oleraceus is a common weed in Brazil, also used as a medicinal plant. Phytochemical prospecting of this species was carried out in this work using extracts obtained in ethanol, water and dichloromethane. A toxicity study of the aqueous extract was also conducted, using the micro crustaceous Artemia salina. The aqueous extract presented sugar reducers, phenolic compounds, tannins, flavonoids and coumarins in its composition. The compounds found in the aqueous extract were also detected in the ethanol extract, except for the coumarins. Saponin, triterpenes and steroids were identified in the dichloromethane extract. The toxicity test on Artemia salina pointed to aqueous extract fractions of 5,117.2 ppm, indicative of low toxicity.

  8. Design, operation, and potential of a culture system for the continuous production of Artemia nauplii

    OpenAIRE

    Lavens, P.; Sorgeloos, P

    1987-01-01

    A flow-through system is described for the controlled production of Artemia nauplii. High densities of adult brine shrimp are induced to ovoviviparity through diet manipulation, optimal culture water exchange, and high constant oxygen levels. The nauplii produced are separated from the culture tank effluents in a special recuperation filter system. The culture water is recirculated over a rotating biodisc, a cross-flow sieve, and a plate separator.The potential of this nauplii production syst...

  9. 卤虫属分类研究进展%Progress on Researches of Taxonomy on Genus Artemia

    Institute of Scientific and Technical Information of China (English)

    张伟峰; 郝浩永; 陈莉

    2008-01-01

    卤虫(Anemia)属于节肢动物门(Phylum Arthropoda),甲壳纲(Class Crustacea),鳃足亚纲(SubclassBranchiopoda),无甲目(Order Anostraca),卤虫科(Family Artemidae).世界卤虫根据生殖方式可分为两性生殖卤虫和孤雌生殖卤虫两大类.利用生殖隔离实验将世界两性卤虫分为8个种:Anemiafranciscana Kellogg、Artemia persimilis Piccinelli et Prosdoeimi、Anemia rnonica Verrill、Anemia salina Linnaeus、Artemia urmianaGünther、Anemia tunisiana Bowen et Sterling、Anemia sinica Cai和Anemia tibetiana Abatzopouios,Zhang et Sorge-loos.其中,我国发现有A.sinica和A.tibetiana两种两性卤虫.孤雌生殖卤虫统称为Artemia parthenogenetica,并在其后加上产地的地名以示区别.

  10. Comparison of bioassays using the anostracan crustaceans Artemia salina and Thamnocephalus platyurus for plant extract toxicity screening Comparação de bioensaios com os crustáceos Artemia salina e Thamnocephalus platyurus para abordagem de extratos de plantas com toxicidade

    OpenAIRE

    Pablo Mayorga; Karen R. Pérez; Sully M. Cruz; Armando Cáceres

    2010-01-01

    Three lethality bioassays, using the salt-water crustacean Artemia salina Leach, Artemiidae, (conventional 96 microwell plate test and the Artoxkit M microbiotest) and the freshwater crustacean Thamnocephalus platyurus Packard, Thamnocephalidae, (Thamnotoxkit F microbiotest), were compared using extracts of ten Guatemalan plant species. It was previously observed that five of them have anti-Artemia activity. These were: Solanum americanum Mill., Solanaceae, Gliricidia sepium (Jacq.) Kunth ex ...

  11. Experimental taphonomy of Artemia reveals the role of endogenous microbes in mediating decay and fossilization.

    Science.gov (United States)

    Butler, Aodhán D; Cunningham, John A; Budd, Graham E; Donoghue, Philip C J

    2015-06-01

    Exceptionally preserved fossils provide major insights into the evolutionary history of life. Microbial activity is thought to play a pivotal role in both the decay of organisms and the preservation of soft tissue in the fossil record, though this has been the subject of very little experimental investigation. To remedy this, we undertook an experimental study of the decay of the brine shrimp Artemia, examining the roles of autolysis, microbial activity, oxygen diffusion and reducing conditions. Our findings indicate that endogenous gut bacteria are the main factor controlling decay. Following gut wall rupture, but prior to cuticle failure, gut-derived microbes spread into the body cavity, consuming tissues and forming biofilms capable of mediating authigenic mineralization, that pseudomorph tissues and structures such as limbs and the haemocoel. These observations explain patterns observed in exceptionally preserved fossil arthropods. For example, guts are preserved relatively frequently, while preservation of other internal anatomy is rare. They also suggest that gut-derived microbes play a key role in the preservation of internal anatomy and that differential preservation between exceptional deposits might be because of factors that control autolysis and microbial activity. The findings also suggest that the evolution of a through gut and its bacterial microflora increased the potential for exceptional fossil preservation in bilaterians, providing one explanation for the extreme rarity of internal preservation in those animals that lack a through gut. PMID:25972468

  12. Interference from ordinarily used solvents in the outcomes of Artemia salina lethality test

    Directory of Open Access Journals (Sweden)

    Sahgal Geethaa

    2013-01-01

    Full Text Available Methanol, ethanol, Tween 20 and dimethyl sulfoxide (DMSO are widely used as dissolving agents in Artemia salina lethality test (aka brine shrimp lethality test [BSLT] to screen the pharmaceutical properties of natural products. Nevertheless, there is lack of toxicity level of these solvents against brine shrimp. High concentration of these organic solvent might be toxic for this zoology invertebrate and interfere in the experimental outcomes. To avoid this, permissible concentration of the solvents used in BSLT was identified. BSLT was performed to evaluate the toxicity effect of Tween 20, methanol, ethanol and DMSO at 24 h post-treatment time point against A. salina. The suggested maximum working concentration (v/v for DMSO, methanol, ethanol was found to be 1.25% and that for Tween 20 was 0.16%. LC 50 for the solvents were 8.5% (DMSO, 6.4% (methanol, 3.4% (ethanol and 2.5% (Tween 20. The findings have shown a toxicity level among the solvents in descending order as Tween 20 > ethanol > methanol > DMSO. DMSO is a safer solvent to be used in BSLT compared with other tested solvents, whereas Tween 20 has been shown to be the most stringent solvent among the tested solvents. The findings are resourcefully useful to avoid interference of solvents in the assessment of natural products using BSLT.

  13. A Novel Porous Carrier Found in Nature for Nanocomposite Materials Preparation: A Case Study of Artemia Egg Shell-Supported TiO2 for Formaldehyde Removal

    Directory of Open Access Journals (Sweden)

    Sufeng Wang

    2015-01-01

    Full Text Available Artemia egg shells have an asymptotic sized pore structure (pore diameter: 500 nm–2500 nm, which could be used as a porous carrier for the preparation of nanocomposite materials. The objective of the present study was to prepare shell-supported TiO2 using a naturally porous carrier, Artemia egg shell, and to exhibit a case study of shell-supported TiO2 for formaldehyde removal. Characterization of shell-TiO2 using SEM-EDS, TEM, and XRD proved that Artemia shell with asymptotic reduction pores (pore diameter: 500 nm–2500 nm can be used as the carrier for nanocomposite materials. Artemia egg shell-supported TiO2 in polycrystalline-like nanostructures can be used for the high efficiency removal (adsorption and degradation of formaldehyde under visible light. Our results suggest that iron, one of the shell’s components, should broaden the absorption of visible light and enhance the photocatalytic efficiency of nanotitanium dioxide under visible light. Due to their interesting absorption and formaldehyde removal qualities, Artemia egg shell, as a novel naturally porous carrier for nanocomposite materials preparation, especially in the preparation of nanocatalysts, is worthy of further study.

  14. Avaliação da bioatividade dos extratos de cúrcuma (Curcuma longa L., Zingiberaceae em Artemia salina e Biomphalaria glabrata Bioactivity evaluation of the turmeric (Curcuma longa L., Zingiberaceae extracts in Artemia salina and Biomphalaria glabrata

    Directory of Open Access Journals (Sweden)

    Carlos R. M. da Silva Filho

    2009-12-01

    Full Text Available A cúrcuma é o rizoma limpo, em boas condições, seco e moído da Curcuma longa L., uma planta herbácea da família Zingiberaceae. Visando novas alternativas para o controle da esquistossomose, os extratos de Curcuma longa L. foram testados para a avaliação da atividade moluscicida contra caramujos adultos da espécie Biomphalaria glabrata, e toxicidade (ensaio de letalidade com Artemia salina. A oleoresina e o óleo essencial de cúrcuma foram ativos contra Artemia salina (CL50 = 80,43 e CL50 = 319,82 μg/mL, respectivamente e também ativos contra os indivíduos adultos de Biomphalaria glabrata (CL50 = 58,3 e CL50 = 46,73 μg/mL, respectivamente. A partir dos resultados obtidos pôde ser concluído que ambos os extratos podem constituir uma alternativa no controle da população desses caramujos e na redução da esquistossomose.The turmeric is the clean rhizome at good conditions, dried and powdered of Curcuma longa L., an herbaceous plant of Zingiberaceae family. Aiming new alternatives for Schistosomiasis control, the Curcuma longa L. extracts were tested for molluscicidal activity evaluation against adult snails of Biomphalaria glabrata specie, and the toxicity (Brine Shrimp Lethality-BSL-bioassay. The oleoresin and the essential oil of turmeric were active against Artemia salina (CL50 = 80.43 and CL50 = 319.82 μg.mL-1, respectively and also active against the adult snails of Biomphalaria glabrata (CL50 = 58.3 and CL50 = 46.73 μg.mL-1, respectively. From the obtained results it was concluded that both extracts can constitute an alternative to population control of these snails and in the reduction of Schistosomiasis.

  15. Identification of the glycerol kinase gene and its role in diapause embryo restart and early embryo development of Artemia sinica.

    Science.gov (United States)

    Cheng, Cheng; Yao, Feng; Chu, Bing; Li, Xuejie; Liu, Yan; Wu, Yang; Mei, Yanli; Wang, Peisheng; Hou, Lin; Zou, Xiangyang

    2014-03-01

    Glycerol kinase (GK) catalyzes the rate-limiting step in glycerol utilization by transferring a phosphate from ATP to glycerol, yielding glycerol 3-phosphate, which is an important intermediate for both energy metabolism and glycerolipid production. Artemia sinica has an unusual diapause process under stress conditions of high salinity, low temperature and lack of food. In the process, diapause embryos of A. sinica (brine shrimp) accumulate high concentrations of glycerol as a cryoprotectant to prevent low temperature damage to embryos. Upon embryo restart, glycerol is converted into glucose and other carbohydrates. Therefore, GK plays an important role in the diapause embryo restart process. However, the role of GK in diapause termination of embryo development in A. sinica remains unknown. In the present study, a 2096 bp full-length cDNA of gk from A. sinica (As-gk) was obtained, encoding putative 551 amino acids, 60.6 kDa protein. As a crucial enzyme in glycerol uptake and metabolism, GK has been conserved structurally and functionally during evolution. The expression pattern of As-gk was investigated by quantitative real-time PCR and Western blotting. Expression locations of As-gk were analyzed using in situ hybridization. As-gk was widely distributed in the early embryo and several main parts of Artemia after differentiation. The expression of As-GK was also induced by stresses such as cold exposure and high salinity. This initial research into the expression pattern and stress response of GK in Artemia provides a sound basis for further understanding of the function and regulation of genes in early embryonic development in A. sinica and the stress response. PMID:24365596

  16. High prevalence of cestodes in Artemia spp. throughout the annual cycle: relationship with abundance of avian final hosts

    Science.gov (United States)

    Sánchez, Marta I.; Nikolov, Pavel N.; GEorgieva, Darina D.; Georgiev, Boyko B.; Vasileva, Gergana P.; Pankov, Plamen; Paracuellos, Mariano; Lafferty, Kevin D.; Green, Andy J.

    2013-01-01

    Brine shrimp, Artemia spp., act as intermediate hosts for a range of cestode species that use waterbirds as their final hosts. These parasites can have marked influences on shrimp behavior and fecundity, generating the potential for cascading effects in hypersaline food webs. We present the first comprehensive study of the temporal dynamics of cestode parasites in natural populations of brine shrimp throughout the annual cycle. Over a 12-month period, clonal Artemia parthenogenetica were sampled in the Odiel marshes in Huelva, and the sexual Artemia salina was sampled in the Salinas de Cerrillos in Almería. Throughout the year, 4–45 % of A. parthenogenetica were infected with cestodes (mean species richness = 0.26), compared to 27–72 % of A. salina (mean species richness = 0.64). Ten cestode species were recorded. Male and female A. salina showed similar levels of parasitism. The most prevalent and abundant cestodes were those infecting the most abundant final hosts, especially the Greater Flamingo Phoenicopterus ruber. In particular, the flamingo parasite Flamingolepis liguloides had a prevalence of up to 43 % in A. parthenogenetica and 63.5 % in A. salina in a given month. Although there was strong seasonal variation in prevalence, abundance, and intensity of cestode infections, seasonal changes in bird counts were weak predictors of the dynamics of cestode infections. However, infection levels of Confluaria podicipina in A. parthenogenetica were positively correlated with the number of their black-necked grebe Podiceps nigricollis hosts. Similarly, infection levels of Anomotaenia tringae and Anomotaenia microphallos in A. salina were correlated with the number of shorebird hosts present the month before. Correlated seasonal transmission structured the cestode community, leading to more multiple infections than expected by chance.

  17. Proteomic analysis of acute responses to copper sulfate stress in larvae of the brine shrimp,Artemia sinica

    Institute of Scientific and Technical Information of China (English)

    周茜; 吴长功; 董波; 李富花; 刘凤岐; 相建海

    2010-01-01

    Proteomics was used to reveal the differential protein expression profiles of acute responses to copper sulfate exposure in larvae of Artemia sinica.Fourteen differentially displayed protein spots were detected and seven of them were identified.Three spots were up-expressed and identified:actin, heat shock protein 70,and chaperone subunit 1;three down-regulated proteins were identified:arginine kinase,elongation factor-2,and glycine-rich protein;and a newly expressed protein was identified as peroxiredoxin....

  18. A cost-effectiveness analysis of live feeds in juvenile turbot Scophthalmus maximus (Linnaeus, 1758) farming: copepods versus Artemia

    DEFF Research Database (Denmark)

    Gedefaw Abate, Tenaw; Nielsen, Rasmus; Nielsen, Max;

    2016-01-01

    items (copepods and Artemia) in juvenile turbot farming. Unit cost of production and profit are compared between the two feeding regimes using a unique data set from an existing turbot fry production facility in Denmark. The result reveals that copepods are not only biochemically superior...... but they are also economically a cost-effective alternative. Thus, a commercial use of copepods will significantly reduce the production costs for turbot. Furthermore, the unexploited economic potential can be utilized for the successful farming of other high-valued marine finfish species such as tuna, flounders...

  19. Naked eye instant reversible sensing of Cu(2+) and its in situ imaging in live brine shrimp Artemia.

    Science.gov (United States)

    Nair, Ratish R; Raju, M; Patel, Neha P; Raval, Ishan H; Suresh, E; Haldar, Soumya; Chatterjee, Pabitra B

    2015-08-21

    A Cu(2+)-specific colorimetric reversible fluorescent receptor was designed and synthesized which showed a naked eye observable colour change from colourless to pink on addition of an aqueous buffer (pH 7.4) solution of 30 ppb Cu(2+). Short response time (≤5 s) and low detection limit (nearly 3 ppb) make suitable as a reliable "dip-in" open eye sensor for Cu(2+). Bio-imaging application in live brine shrimp Artemia enabled to detect Cu(2+) at as low as 10 ppb exposure. PMID:26145434

  20. Assessment of Cytotoxic Activity of Three Plants of Pigweed, Bermuda grass and Burdock via Artemia Salina Test

    OpenAIRE

    parisa sadighara; tahere aliesfahani; mahdie jafari; atousa ziaei; tahere farkhondeh

    2010-01-01

    Introduction: Pigweed is a weed which grows in the pastures of Iran. Local people use the plant leaves to cook traditional food. Bermuda grass with its rapid growth and distribution is regarded a real threat to prairies and it can lead to tremors syndrome in cattle and sheep. Burdock which also grows in many parts of Iran is used as a medicinal herb. In this study, the cytotoxicity potential of the three plants was assessed via Artemia Salina test. Methods: Pigweed, Bermuda grass and burdock ...

  1. Assessment of toxicity of Moringa oleifera flower extract to Biomphalaria glabrata, Schistosoma mansoni and Artemia salina.

    Science.gov (United States)

    Rocha-Filho, Cláudio A A; Albuquerque, Lidiane P; Silva, Luanna R S; Silva, Patrícia C B; Coelho, Luana C B B; Navarro, Daniela M A F; Albuquerque, Monica C P A; Melo, Ana Maria M A; Napoleão, Thiago H; Pontual, Emmanuel V; Paiva, Patrícia M G

    2015-08-01

    This study reports the effect of an aqueous extract from Moringa oleifera Lam. flowers on Biomphalaria glabrata embryos and adults and on Schistosoma mansoni adult worms. The extract contains tannins, saponins, flavones, flavonols, xanthones, and trypsin inhibitor activity. The toxicity of the extract on Artemia salina larvae was also investigated to determine the safety of its use for schistosomiasis control. After incubation for 24h, the flower extract significantly (p<0.05) delayed the development of B. glabrata embryos and promoted mortality of adult snails (LC50: 2.37±0.5mgmL(-1)). Furthermore, treatment with the extract disrupted the development of embryos generated by snails, with most of them remaining in the blastula stage while control embryos were already in the gastrula stage. Flower extract killed A. salina larvae with a LC50 value (0.2±0.015mgmL(-1)) lower than that determined for snails. A small reduction (17%) in molluscicidal activity was detected when flower extract (2.37mgmL(-1)) was exposed to tropical environmental conditions (UVI index ranging from 1 to 14, temperature from 25 to 30°C, and 65% relative humidity). Toxicity to A. salina was also reduced (LC50 value of 0.28±0.01mgmL(-1)). In conclusion, M. oleifera flower extract had deleterious effects on B. glabrata adults and embryos. However, unrestricted use to control schistosomiasis should be avoided due to the toxicity of this extract on A. salina. PMID:25867917

  2. Assessment of toxicity of Moringa oleifera flower extract to Biomphalaria glabrata, Schistosoma mansoni and Artemia salina.

    Science.gov (United States)

    Rocha-Filho, Cláudio A A; Albuquerque, Lidiane P; Silva, Luanna R S; Silva, Patrícia C B; Coelho, Luana C B B; Navarro, Daniela M A F; Albuquerque, Monica C P A; Melo, Ana Maria M A; Napoleão, Thiago H; Pontual, Emmanuel V; Paiva, Patrícia M G

    2015-08-01

    This study reports the effect of an aqueous extract from Moringa oleifera Lam. flowers on Biomphalaria glabrata embryos and adults and on Schistosoma mansoni adult worms. The extract contains tannins, saponins, flavones, flavonols, xanthones, and trypsin inhibitor activity. The toxicity of the extract on Artemia salina larvae was also investigated to determine the safety of its use for schistosomiasis control. After incubation for 24h, the flower extract significantly (p<0.05) delayed the development of B. glabrata embryos and promoted mortality of adult snails (LC50: 2.37±0.5mgmL(-1)). Furthermore, treatment with the extract disrupted the development of embryos generated by snails, with most of them remaining in the blastula stage while control embryos were already in the gastrula stage. Flower extract killed A. salina larvae with a LC50 value (0.2±0.015mgmL(-1)) lower than that determined for snails. A small reduction (17%) in molluscicidal activity was detected when flower extract (2.37mgmL(-1)) was exposed to tropical environmental conditions (UVI index ranging from 1 to 14, temperature from 25 to 30°C, and 65% relative humidity). Toxicity to A. salina was also reduced (LC50 value of 0.28±0.01mgmL(-1)). In conclusion, M. oleifera flower extract had deleterious effects on B. glabrata adults and embryos. However, unrestricted use to control schistosomiasis should be avoided due to the toxicity of this extract on A. salina.

  3. Distribution, abundance and density estimates of franciscanas, Pontoporia blainvillei (Cetacea: Pontoporiidae, in Babitonga bay, southern Brazil Distribuição e estimativas de abundância e densidade de franciscanas, Pontoporia blainvillei (Cetacea: Pontoporiidae, na baía da Babitonga, sul do Brasil

    Directory of Open Access Journals (Sweden)

    Marta J. Cremer

    2008-09-01

    Full Text Available Pontoporia blainvillei (Gervais & d'Orbigny, 1844 is threatened throughout its distribution. The species can be found year-round in the Babitonga bay estuary (26º 02'-26º 28'S and 48º28'-48º50'W, in the north coast of the state of Santa Catarina, Brazil. Boat surveys were conducted in order to evaluate its abundance and density between 2000 and 2003. Sampling was random and stratified, with 46 transects in five sub-areas, comprising a total area of 160 km². Data collection was conducted following the linear transect method with distance sampling. A total of 1174.7 km was scanned and 38 groups were observed. Franciscanas were not uniformly distributed in Babitonga bay. Group size ranged from one to 13 animals (mean ± SD = 5.02 ± 3.62. Model 1 (Half-Normal showed the best fit to the data. The estimated population size was 50 animals and the density was 0.32 individuals km-2. Density estimates evaluated in the sub-areas where franciscanas occurred resulted in a density of 0.46 individuals km-2. Monitoring this population is of considerable importance due to the constant threats that this species faces in this bay.Pontoporia blainvillei (Gervais & d'Orbigny, 1844 ocorre ao longo de todo o ano no estuário da baía da Babitonga, no litoral norte de Santa Catarina, sul do Brasil. Foram realizadas amostragens com o objetivo de obter informações sobre sua abundância e densidade populacional nesta área entre os anos de 2000 e 2003. A amostragem foi aleatória e estratificada, com 46 transecções estabelecidas em cinco grandes sub-áreas, compreendendo 160 km². A coleta de dados foi conduzida utilizando o método de transecções lineares com amostragem de distância. Foram percorridos 1174,7 km e 38 grupos foram registrados. As franciscanas não apresentaram uma distribuição uniforme na baía da Babitonga. O tamanho de grupo variou de um a 13 animais (5,02 ± 3,62. O Modelo 1 (Meio-Normal promoveu o melhor ajustamento dos parâmetros. A

  4. A note on the biogeographical origin of the brine shrimp Artemia urmiana Günther, 1899 from Urmia Lake, Iran.

    Science.gov (United States)

    Eimanifar, Amin; Asem, Alireza; Djamali, Morteza; Wink, Michael

    2016-01-01

    The brine shrimp Artemia urmiana, an abundant inhabitant of the hypersaline Urmia Lake in northwestern Iran, has recently been described from Lake Koyashskoe, also a shallow hypersaline lake that is located on the Black Sea coast of the Crimean Peninsula (Ukraine). This discovery has questioned the endemicity of A. urmiana in Urmia Lake and has also brought into question the biogeographical origin of this species. In the present study, we combined recent genetic divergence data (mtDNA-COI) with palaeoecological evidence to address the biogeographical origin of A. urmiana. Calibration of the molecular clock of the COI region was set by assigning the age of the micro-crustacean Daphnia pulex minimally at 145 Mya. The divergence age of A. urmiana in Urmia Lake dates back to 383,000 years, whereas Ukrainian Artemia reflects a very young populations that diverged about 196,000 years ago. Palaeoecological evidence suggests that the age of the major habitat of A. urmiana i.e. Urmia Lake goes back to the Tertiary Period while the Ukranian habitats of the species are very young, by virtue of geological features of the Holocene age. We conclude that the biogeographical origin of A. urmiana is outside of Europe and the current state of knowledge strongly suggests that Urmia Lake has been the major source of its expansion into its modern habitats in Europe. PMID:27394547

  5. Assessment of Cytotoxic Activity of Three Plants of Pigweed, Bermuda grass and Burdock via Artemia Salina Test

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    parisa sadighara

    2010-01-01

    Full Text Available Introduction: Pigweed is a weed which grows in the pastures of Iran. Local people use the plant leaves to cook traditional food. Bermuda grass with its rapid growth and distribution is regarded a real threat to prairies and it can lead to tremors syndrome in cattle and sheep. Burdock which also grows in many parts of Iran is used as a medicinal herb. In this study, the cytotoxicity potential of the three plants was assessed via Artemia Salina test. Methods: Pigweed, Bermuda grass and burdock were collected from Ghaemshahr in the North of Iran. The leaves were dried and the essence of the three plants was extracted. The larvaes were hatched from cysts of Artemia salina at 26˚C in filtered seawater. The plant extracts with different concentration (10,100 and 1000ppm were added to the solution larvaes. Results: The LC50 values (the concentration which needed to die half the larvaes were measured for pigweed, Bermuda grass and burdock at 1640, 990, and 840 ppm, respectively. Conclusion: The results indicate that compared to the two other species, there is more priority for burdock to be studied in further studies for identification and assessment of toxicity

  6. Preparation of Chitosan from Brine Shrimp (Artemia urmiana Cyst Shells and Effects of Different Chemical Processing Sequences on the Physicochemical and Functional Properties of the Product

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    Farnood Shokouhi Sabet Jalali

    2008-06-01

    Full Text Available Chitosan (CS was prepared from Artemia urmiana cyst shells using the same chemical process as described for the other crustacean species, with minor adjustments in the treatment conditions. The influence of modifications of the CS production process on the physiochemical and functional properties of the CS obtained was examined. The study results indicate that Artemia urmiana cyst shells are a rich source of chitin as 29.3-34.5% of the shell’s dry weight consisted of this material. Compared to crab CS (selected as an example of CS from a different crustacean source Artemia CS exhibited a medium molecular weight (4.5-5.7 ×105 Da, lower degree of deacetylation (67-74% and lower viscosity (29-91 centiposes. The physicochemical characteristics (e.g., ash, nitrogen and molecular weight and functional properties (e.g., water binding capacity and antibacterial activity of the prepared Artemia CSs were enhanced, compared to control and commercial samples, by varying the processing step sequence.

  7. Preparation of chitosan from brine shrimp (Artemia urmiana) cyst shells and effects of different chemical processing sequences on the physicochemical and functional properties of the product.

    Science.gov (United States)

    Tajik, Hossein; Moradi, Mehran; Rohani, Seyed Mehdi Razavi; Erfani, Amir Mehdi; Jalali, Farnood Shokouhi Sabet

    2008-06-06

    Chitosan (CS) was prepared from Artemia urmiana cyst shells using the same chemical process as described for the other crustacean species, with minor adjustments in the treatment conditions. The influence of modifications of the CS production process on the physiochemical and functional properties of the CS obtained was examined. The study results indicate that Artemia urmiana cyst shells are a rich source of chitin as 29.3-34.5% of the shell's dry weight consisted of this material. Compared to crab CS (selected as an example of CS from a different crustacean source) Artemia CS exhibited a medium molecular weight (4.5-5.7 x10(5) Da), lower degree of deacetylation (67-74%) and lower viscosity (29-91 centiposes). The physicochemical characteristics (e.g., ash, nitrogen and molecular weight) and functional properties (e.g., water binding capacity and antibacterial activity) of the prepared Artemia CSs were enhanced, compared to control and commercial samples, by varying the processing step sequence.

  8. Habitat use and diet selection of northward migrating waders in the Sivash (Ukraine): the use of brine shrimp Artemia salina in a variably saline lagoon complex.

    NARCIS (Netherlands)

    Verkuil, Y.; Have, van der T.M.; Winden, van der J.; Chernichko, I.I.

    2003-01-01

    Wader species migrating through the Sivash (Ukraine) use hypersaline and brackish lagoons. We studied the use of the two habitat types, and focused on the profitability of Brine Shrimp Artemia salina, prey species in hypersaline lagoons for Dunlins Calidris alpina, Curlew Sandpipers Calidris ferrugi

  9. Habitat use and diet selection of northward migrating waders in the Sivash (Ukraine) : The use of Brine Shrimp Artemia salina in a variably saline lagoon complex

    NARCIS (Netherlands)

    Verkuil, Y; Van der Have, TM; Van der Winden, J; Chernichko, [No Value

    2003-01-01

    Wader species migrating through the Sivash (Ukraine) use hypersaline and brackish lagoons. We studied the use of the two habitat types, and focused on the profitability of Brine Shrimp Artemia salina, prey species in hypersaline lagoons for Dunlins Calidris alpina, Curlew Sandpipers Calidris ferrugi

  10. Culture of Artemia on rice bran: the conversion of a waste-product into highly nutritive animal protein

    OpenAIRE

    Sorgeloos, P.; Baeza-Mesa, M.; Bossuyt, E.; Bruggeman, E.; Dobbeleir, J.; Versichele, D.; Laviña, E.; Bernardino, A.

    1980-01-01

    The age-old problem of finding a cheap and suitable food for Artemia is finally solved with rice bran, in fact a waste-product which is available at a very low price in many countries all over the world.

  11. Oxygen-binding characteristics of three extracellular haemoglobins of Artemia salina.

    Science.gov (United States)

    D'Hondt, J; Moens, L; Heip, J; D'Hondt, A; Kondo, M

    1978-06-01

    The oxygen-binding characteristics of the three extracellular haemoglobins of brine shrimp (Artemia salina) were studied in vitro by using highly purified preparations. Haemoglobin I is induced last in the development of brine shrimps when functional gills are formed. It has the lowest oxygen affinity (p(50) 5.34mmHg), an intermediate Bohr effect (ø -0.09 at 20 degrees C) above pH8 and a temperature-sensitivity (DeltaH -44.8 to -45.6kJ/mol at pH8-9) comparable with those observed with other invertebrate haemoglobins [Weber & Heidemann (1977) Comp. Biochem. Physiol. A57, 151-155]. Haemoglobin II, which is the first to be induced, soon after hatching of nauplius larvae, persists generally throughout the whole adult life. It has an intermediate oxygen affinity (p(50) 3.7mmHg), the highest Bohr effect (ø -0.21 at 20 degrees C) above pH8 and a similar temperature-sensitivity (DeltaH -46.0 to -54.8kJ/mol at pH8-9) as haemoglobin I. However, haemoglobin III, which is induced second several hours after the induction of haemoglobin II but disappearing from the haemolymph in the middle of adult life, has the highest oxygen affinity (p(50) 1.8mmHg), the lowest Bohr effect (ø -0.03 at 20 degrees C) above pH8.5 and a high resistance against temperature variation between 10 and 25 degrees C at pH8.5-9 (DeltaH -22.6 to -23.0kJ/mol). At pH7.5-8, haemoglobin III exhibits a similar temperature-sensitivity under 30 degrees C as do other haemoglobins. All three haemoglobins have a rather low co-operativity, with Hill coefficients (h 1.6-1.9 at pH8.5), which are dependent on both pH and temperature. The highest co-operativity was observed at 20 degrees C and pH9 for haemoglobins I and II, whereas it was at 27 degrees C and pH8.5 for haemoglobin III. Thus the oxygen-binding behaviour of haemoglobin III in vitro is significantly different from those of haemoglobins I and II and indicates possibly its specific physiological role in vivo in the adaptive process in the natural

  12. Efeito alelopático e toxicidade frente à Artemia salina Leach dos extatos do fruto de Euterpe edulis Martius Allelopathic effects and toxicity against Artemia salina Leach of extracts of the fruit of Euterpe edulis Martius

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    Cristina Peitz de Lima

    2011-06-01

    Full Text Available Alelopatia é um processo envolvendo metabólitos secundários produzidos por plantas que infl uenciam o crescimento e desenvolvimento de sistemas agrícolas. Devido à toxicidade dos herbicidas sintéticos para o meio ambiente e para a saúde humana tem-se aumentado o interesse na exploração da alelopatia como uma alternativa para o controle de plantas daninhas. O presente trabalho avaliou efeito dos extratos dos frutos de Euterpe edulis Martius sobre o desenvolvimento de cipselas e plântulas de Lactuca sativa Linné, foram determinados o índice de velocidade de germinação, o crescimento da radícula e do hipocótilo. Para a avaliação da toxicidade dos extratos foi realizado o ensaio de toxicidade frente ao microcrustáceo Artemia salina Leach determinando-se a CL50 e percentual de mortalidade. A fração remanescente demonstrou efeito alelopático, pois todas as concentrações alteraram os valores do índice de velocidade de germinação e as concentrações de 0,2 e 0,4 mg inibiram tanto o crescimento da radícula quanto o crescimento do hipocótilo. No ensaio de toxicidade todos os extratos apresentaram CL50 superior a 1000 ppm e 0% de mortalidade das artemias, indicando a não toxicidade dos extratos.Allelopathy is a process involving secondary metabolites produced by plants that influence growth and development of agricultural systems. Because of the toxicity of synthetic herbicides to the environment and human health, there has been increased interest in exploiting allelopathy as an alternative for weed control. This study evaluated the eff ect of extracts of Euterpe edulis Martius fruits on the development of cypselae and seedlings of Lactuca sativa Linné; the germination speed index, radicle and hypocotyl growth were determined. To evaluate the toxicity of the extracts the toxicity test against Artemia salina Leach was used, where the LC50 and mortality rate were determined. Th e remaining fraction showed allelopathic effect

  13. Zebrafish fed on recombinant Artemia expressing epinecidin-1 exhibit increased survival and altered expression of immunomodulatory genes upon Vibrio vulnificus infection.

    Science.gov (United States)

    Jheng, Yu-Hsuan; Lee, Lin-Han; Ting, Chen-Hung; Pan, Chieh-Yu; Hui, Cho-Fat; Chen, Jyh-Yih

    2015-01-01

    Artemia has been used extensively in aquaculture as fodder for larval fish, shrimp, and shellfish. Epinecidin-1, an antimicrobial peptide, was isolated from grouper (Epinephelus coioides) in 2005. Epinecidin-1 has been previously reported to possess antimicrobial activity against several Gram-positive and Gram-negative bacterial species, including Staphylococcus coagulase, Pseudomonas aeruginosa, Streptococcus pyogenes, and Vibrio vulnificus. In this study, we used electroporation to introduce plasmid DNA encoding a green fluorescent protein (EGFP)-epinecidin-1 fusion protein under the control of the cytomegalovirus (CMV) promoter into decapsulated Artemia cysts. Optimization of various properties (including cyst weight (0.2 g), plasmid concentration (50 μg/100 μl), and pulse voltage (150 V), length (10 ms), and number (2)) resulted in a hatching rate of 41.15%, a transfection efficiency of 49.81%, and a fluorescence intensity (A.U.) of 47.46. The expression of EGFP-epinecidin-1 was first detected by quantitative RT-PCR at 120 h post-electroporation, and protein was identified by Western blot at the same time. Furthermore, the EGFP-epinecidin-1 protein inhibited V. vulnificus (204) growth, as demonstrated by zone of inhibition studies. Zebrafish fed on transgenic Artemia expressing CMV-gfp-epi combined with commercial fodder were more resistant to infection by V. vulnificus (204): survival rate was enhanced by over 70% at 7, 14, and 21 days post-infection, and bacterial numbers in the liver and intestine were reduced. In addition, feeding of transgenic Artemia to zebrafish affected the immunomodulatory response to V. vulnificus (204) infection; expression of immune-responsive genes, including hepcidin and defbl2, was altered, as shown by qPCR. These findings suggest that feeding transgenic Artemia expressing CMV-gfp-epi to larval fish has antimicrobial effects, without the drawbacks of introducing drug residues or inducing bacterial drug resistance.

  14. The potential role of As-sumo-1 in the embryonic diapause process and early embryo development of Artemia sinica.

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    Bing Chu

    Full Text Available During embryonic development of Artemia sinica, environmental stresses induce the embryo diapause phenomenon, required to resist apoptosis and regulate cell cycle activity. The small ubiquitin-related modifier-1 (SUMO, a reversible post-translational protein modifier, plays an important role in embryo development. SUMO regulates multiple cellular processes, including development and other biological processes. The molecular mechanism of diapause, diapause termination and the role of As-sumo-1 in this processes and in early embryo development of Artemia sinica still remains unknown. In this study, the complete cDNA sequences of the sumo-1 homolog, sumo ligase homolog, caspase-1 homolog and cyclin B homolog from Artemia sinica were cloned. The mRNA expression patterns of As-sumo-1, sumo ligase, caspase-1, cyclin B and the location of As-sumo-1 were investigated. SUMO-1, p53, Mdm2, Caspase-1, Cyclin B and Cyclin E proteins were analyzed during different developmental stages of the embryo of A. sinica. Small interfering RNA (siRNA was used to verify the function of sumo-1 in A. sinica. The full-length cDNA of As-sumo-1 was 476 bp, encoding a 92 amino acid protein. The As-caspases-1 cDNA was 966 bp, encoding a 245 amino-acid protein. The As-sumo ligase cDNA was 1556 bp encoding, a 343 amino acid protein, and the cyclin B cDNA was 739 bp, encoding a 133 amino acid protein. The expressions of As-sumo-1, As-caspase-1 and As-cyclin B were highest at the 10 h stage of embryonic development, and As-sumo ligase showed its highest expression at 0 h. The expression of As-SUMO-1 showed no tissue or organ specificity. Western blotting showed high expression of As-SUMO-1, p53, Mdm2, Caspase-1, Cyclin B and Cyclin E at the 10 h stage. The siRNA caused abnormal development of the embryo, with increased malformation and mortality. As-SUMO-1 is a crucial regulation and modification protein resumption of embryonic diapause and early embryo development of A. sinica.

  15. Observações preliminares sobre a toxicidade do ϒBHC e do cloreto de mercúrio à Artemia salina Preliminary observations on the toxicity of ϒBHC and mercuric cloride on Artemia salina

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    Salvador Airton Gaeta

    1983-01-01

    Full Text Available São apresentados os resultados de bioensaios com larvas de Artemia salinacolocadas em misturas de γBHC e HgCl2, a fim de se compararem os efeitos das mesmas com aqueles obtidos quando essas duas substancias atuam isoladamente. A CL50 para o yBHC foi quase que o dobro do valor para o HgCl2. O efeito da primeira dose foi observado para aproximadamente 16% da população (CL16, enquanto que, para o γBHC, o foi em 2,3% da população (CL2,3. Assim, as doses subseqüentes foram mais efetivas para o HgCl2 que para o γBHC. A dose efetiva 50% (ED50 ê mais ou menos igual para o γBHC e para o γBHC + HgCl2, mas em doses altas o YBHC seria mais efetivo, enquanto que em doses baixas a mistura e que o seria.Results of bio-assays using Artemia salina larvae in γBHC-HgCl2 mixture are presented. The results obtained are compared with those obtained using the two chemicals separately. The LC50 for γBHC was almost double that for HgCl2. The effect due to the primary dose of HgCl2 was observed for approximately 16% of the population (LC2.3 while for γBHC the population percentage was 2.3 (LC2.3. As a consequence, subsequent doses were more effective for HgCl2 than for γBHC. The effective dose 50% (ED50 is about the same for γBHC and for γBHC + HgCl2 mixture, though in higher doses BHC would be more effective, while in smaller doses the mixture would predominate.

  16. Optimizing the co-feeding strategy of Persian sturgeon (Acipenser persicus larvae using Artemia nauplii and formulated diet

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    Naser Agh

    2013-07-01

    Full Text Available High mortality and labor costs are associated with first-feeding sturgeon culture, particularly during the period of dietary transition from live to formulated feed. Therefore we investigated the effects of various feeding treatments on the survival and growth of the Persian sturgeon (Acipenser persicus larvae during a 20-day culture period. Three replicate groups (250 fish/replicate of first-feeding larvae were fed according to four main feeding regimes: (1 live food (live nauplii of brine shrimp Artemia urmiana; (2 indirect transition (5 days live food followed by gradual transition to formulated diet; (3 direct transition (using different combinations of live and formulated diet from the start feeding onwards; (4 formulated feed (FD from the start feeding. Results indicated that growth and survival were higher in the indirect transition feeding regime than in other regimes. Based on our study, co-feeding of A. persicus should start five days after prior feeding with live food.

  17. Proteomic analysis of acute responses to copper sulfate stress in larvae of the brine shrimp, Artemia sinica

    Science.gov (United States)

    Zhou, Qian; Wu, Changgong; Dong, Bo; Li, Fuhua; Liu, Fengqi; Xiang, Jianhai

    2010-03-01

    Proteomics was used to reveal the differential protein expression profiles of acute responses to copper sulfate exposure in larvae of Artemia sinica. Fourteen differentially displayed protein spots were detected and seven of them were identified. Three spots were up-expressed and identified: actin, heat shock protein 70, and chaperone subunit 1; three down-regulated proteins were identified: arginine kinase, elongation factor-2, and glycine-rich protein; and a newly expressed protein was identified as peroxiredoxin. The study indicates the involvement of all the differentially expressed proteins in the early responses of protein expression, and in the survival of A. sinica in the presence of copper and other heavy metals; the findings improve understanding of the organism’s adaptive responses and resistance.

  18. Analysis of toxicity of Anacardium occidentale L. extract submitted to ionizing radiation on embryos of Biomphalaria glabrata and Artemia salina

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Hianna A.M.F.; Sa, Jose L.F.; Lima, Claudia S.A.; Amancio, Francisco F.; Melo, Ana M.M.A., E-mail: hiannaamfs@gmail.com, E-mail: luismuma6@gmail.com, E-mail: claudia.salima@gmail.com, E-mail: amancioff@bol.com.br, E-mail: amdemelo@hotmail.com [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Biofisica e Radiobiologia; Ribeiro, Luanna R.S.; Santos, Gustavo H.F.; Silva, Edvane B., E-mail: luannaribeiro_lua@hotmail.com, E-mail: santosghf@hotmail.com, E-mail: edvborges@yahoo.com.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear. Grupo de Estudos em Radioprotecao e Radioecologia

    2013-07-01

    The use of gamma radiation as a sterilization method for herbs, herbal medicines and foods, shows positive results regarding the retention of such products, economy and safety of the method. However, it is known that this method of processing plant material can cause chemical changes in these products related to the type of material, its components and the dose received. Evaluated, in the present study, the action of gamma radiation as a modifier of toxicity extract of Anacardium occidentale Linn. To evaluate the toxicity of the extract irradiated at doses of 5.0, 7.5 and 10.0 kGy and concentrations of 250, 500 and 1000 mg/L was used bioassays with Artemia salina and Biomphalaria glabrata. For the test to A. salina, 520 specimens were used divided into groups of 10 larvae. For the bioassay with B. glabrata, 3900 specimens were used divided into groups of, approximately, 100 embryos. Larvae of A. salina and embryos were subjected to extracts irradiated and unirradiated for 24 hours. The bioassay with A. salina, showed a decrease, compared to extract unirradiated and irradiated at doses of 5.0 and 7.5 kGy, of extract irradiated with 10 kGy, where the mortality did not differ from the control group. In tests with embryos was observed an increase in the toxicity of the extract at a dose of 7.5 kGy and a decrease in the dose of 10.0 kGy. The radiation promoted changes in the toxicity of leaves extracts of Anacardium occidentale Linn. on embryos of Biomphalaria glabrata and Artemia salina. (author)

  19. Síntese de 1,3,5-triazinas substituídas e avaliação da toxicidade frente a Artemia Salina leach Synthesis of substituted 1,3,5-triazines and toxicity evaluation against Artemia Salina leach

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    Márcia Ferreira Cavalcante

    2000-02-01

    Full Text Available The synthesis of ten symmetrically and unsymmetrically substituted 1,3,5-triazines by Phase Transfer Catalysis (PTC method is described. Their toxicities were determined against Artemia salina Leach. The LD50 values have also been obtained for these compounds.

  20. Physiological characteristics and stress resistance of great sturgeon (Huso huso) juveniles fed with vitamins C, E, and HUFA-enriched Artemia urmiana nauplii.

    Science.gov (United States)

    Jalali, Mohammad Ali; Hosseini, Seyed Abbas; Imanpour, Mohammad Reza

    2010-09-01

    This study was carried out to examine the effect of Artemia urmiana nauplii enriched with HUFA, and vitamins C and E on stress tolerance, hematocrit, and biochemical parameters of great sturgeon, Huso huso juveniles. Cod liver oil (EPA 18% and DHA 12%), ascorbyl-6-palmitate and alpha-tocopherol acetate were used as lipid, and vitamin C and E sources, respectively. Beluga juveniles at the stage of first feeding (69.7 +/- 5.9 mg body weight) were randomly divided into five treatments and three tanks were assigned to each diet. All fish groups were fed non-enriched Artemia for the initial 5 days and then fed enriched Artemia for 7 days. Juveniles were fed with Artemia enriched with HUFA + 20% vitamin C (C group); HUFA + 20% vitamin E-enriched Artemia nauplii (E group); HUFA + 20% vitamin C + 20% vitamin E (C and E group); HUFA without vitamins (HUFA) and non-enriched Artemia (control). After the period of enrichment, Juveniles were fed with Daphnia sp. from the 13th to the 40th day. At day 40, the fish were transferred directly from fresh water (0.5 ppt) to brackish water (6 ppt for 4 days and 12 ppt for 2 days) and warm water (from 27 to 33 degrees C) to evaluate juvenile resistance to salinity and thermal shocks. Moreover, all treatments were separately exposed to freshwater in tanks with the same capacity as used for osmotic and thermal tests (as fresh water control). The addition of vitamins C, E, and C + E to HUFA significantly increased fish resistance to 12 ppt salinity and temperature stress tests, whereas survival was not significantly different among challenges at 6 ppt. There was no significant difference in the hematocrit index under stress conditions. Enrichment had significant influence on plasma Na(+) level in the C group on the 4th day at 6 ppt. Na(+) and Ca(2+) concentrations in C, E, and C and E groups on the 1st day at 12 ppt, and Ca(2+) level in E group on the 2nd day at 12 ppt were lower than the other groups. The glucose level in the C and C and

  1. Comparison of bioassays using the anostracan crustaceans Artemia salina and Thamnocephalus platyurus for plant extract toxicity screening Comparação de bioensaios com os crustáceos Artemia salina e Thamnocephalus platyurus para abordagem de extratos de plantas com toxicidade

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    Pablo Mayorga

    2010-12-01

    Full Text Available Three lethality bioassays, using the salt-water crustacean Artemia salina Leach, Artemiidae, (conventional 96 microwell plate test and the Artoxkit M microbiotest and the freshwater crustacean Thamnocephalus platyurus Packard, Thamnocephalidae, (Thamnotoxkit F microbiotest, were compared using extracts of ten Guatemalan plant species. It was previously observed that five of them have anti-Artemia activity. These were: Solanum americanum Mill., Solanaceae, Gliricidia sepium (Jacq. Kunth ex Walp., Fabaceae, Neurolaena lobata (L. Cass., Asteraceae, Petiveria alliacea L., Phytolaccaceae, and Ocimum campechianum Mill., Lamiaceae. The five others: Curatella americana L., Dilleniaceae, Prunus barbata Koehne, Rosaceae, Quercus crispifolia Trel., Fagaceae, Rhizophora mangle L., Rhizophoraceae, and Smilax domingensis Willd., Smilacaceae, do not. All plants without anti-Artemia activity had no lethal effects in both assays with A. salina. For the plants with anti-Artemia activity the Artoxkit M was not sensitive to G. sepium and the conventional Artemia test was not sensitive to S. americanum, G. sepium and N. lobata. All the plant extracts, except for that of C. americana, had lethal effects on T. platyurus and the lethal median concentration (LC50 levels for this organism were in all cases substantially lower than those of the salt-water test species. This study revealed that T. platyurus is a promising test species worth further in depth investigation for toxicity screening of plant extracts with potential medicinal properties.Três bioensaios de letalidade com o crustáceo de água salgada Artemia salina Leach, Artemiidae, (teste convencional em microplaca de 96 poós Artoxkit microbiotest M e o crustáceo de água doce Thamnocephalus platyurus Packard, Thamnocephalidae (Thamnotoxkit microbiotest F, foram comparados utilizando extratos de dez espécies de plantas da Guatemala. Foi previamente observado que cinco delas possuem atividade anti-Artemia

  2. Evaluation of growth and survival rate of Artemia parthenogenetica feed with micro algae (Isochrysis galbana and Chlorella vulgaris and bakery yeast (Saccharomyces cerevisiae

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    Mehdi Dehghan

    2011-10-01

    Full Text Available This study was done to evaluate growth and survival rate of Maharloo lake artemia (ArtemiaParthenogenetica (Bowen & Sterling, 1978 which feed with two species of microalgae (IsochrysisGalbana and Chlorella vulgaris and bakery yeast (Saccharomyces cerevisiae with different nutritiousingredients for 15 days. We evaluated them in 3rd, 7th, 11th and 15thdays of cultivation period for 4 times. This experiment was done in completely randomized design with 4 treatments (3 treatments and 1 control and each treatment has 3 replicates. Artemia parthenogenetica nauplii were feed with three different types of food that includes Isochrysis galbana microalgae (T1, Chlorella vulgaris (T2 and Saccharomyces cerevisiae yeast (T4. Control had feed with blend of these three matters. After 15 days the highest survival rate was observed in control (84.00 and the lowest one was related to the T4 (59.58 which feed with Saccharomyces cerevisiae yeast (p<0.05. The highest growth rate was observed in T4, T3, followed by T1 and T2 respectively. Achievement results showed significantdifferences between control and other treatments (p<0.05. This study proved that treatments whichfeed with blend of two micro algae's species and bakery yeast have higher survival ability than theother treatments.

  3. Sudden weaning of angel fish pterophyllum scalare (Lichtenstein) (Pisces; Cichlidae) larvae from brine shrimp (Artemia sp) nauplii to formulated larval feed.

    Science.gov (United States)

    Herath, Sandamali Sakunthala; Atapaththu, Kerthi Sri Senarathna

    2013-12-01

    This study investigated the effects of sudden weaning of angel fish larvae (Pteraphylum scalari) from Artemia nauplii to commercial larval feed. Four days post hatch (DPH) larvae were reared in four different weaning protocols (TR1-TR4) with triplicates in a complete randomize design. Larvae in TR1 and TR4 were exclusively fed Artemia nauplii and dry feed respectively. In TR2 and TR3, larvae were initially fed Artemia nauplii and suddenly wean to formulated feed on 14 DPH and 7 DPH respectively. The experiment was lasted for 28 days. At the end of the experiment, final mean weight (FW), total length (FL), height (FH), Daily Weight Gain (DWG), Specific Growth Rate (SGR), survival and stress index were compared. Significantly highest (P < 0.05) FW, DWG and SGR were observed in TR1 and TR2 while former values of TR3 were not significantly different from TR1. Highest FL observed in TR1 and TR2 while FL of TR2 was statistically similar to that of TR3. The poorest growth was observed in larvae solely fed formulated feed. Survival and the stress index were independent from weaning methods. Although sudden weaning is possible on 7 DPH, larvae showed comparatively higher growth when switch off to formulate feed on 14 DPH. PMID:23626927

  4. Anticipation of Artemia sp. supply in the larviculture of the barber goby Elacatinus figaro (Gobiidae: Teleostei influenced growth, metamorphosis and alkaline protease activity

    Directory of Open Access Journals (Sweden)

    Maria Fernanda da Silva-Souza

    2015-09-01

    Full Text Available The barber goby Elacatinus figaro is considered endangered due to overexploitation by the ornamental industry. Farming marine ornamental fishes, especially the threatened ones, can be one of the measures to minimize the pressure on the natural stocks. Among the priority issues for their production is the determination of the most appropriate feeding management. The feeding protocol commonly used in the larviculture of barber goby, when the start of Artemia sp. offer occurred at the 18th DAH (days after hatching (treatment T18, was modified, by anticipating brine shrimp supply in 6 days (treatment T12. Alkaline proteases activity, growth and metamorphosis of larvae were evaluated in both protocols. Juveniles at T12 showed higher weight (0.04 ± 0.001 g and lower activity of total alkaline proteases (1.3 ± 0.2 mU mg-1 protein compared to T18 (0.02 ± 0.001 g; 2.8 ± 0.4 mU mg-1 protein, respectively. With anticipation of brine shrimp, the commencing and end of larval transformation was observed earlier (at 24 and 34 DAH, respectively in comparison to those with the supply of Artemia sp. at 18 DAH (27 and 41 DAH, respectively. Thus, the Artemia sp. anticipation was beneficial during the larviculture of the barber goby, considering that larvae reached metamorphosis earlier.

  5. Copper(II) complexes with 2-pyridineformamide-derived thiosemicarbazones: Spectral studies and toxicity against Artemia salina

    Science.gov (United States)

    Ferraz, Karina O.; Wardell, Solange M. S. V.; Wardell, James L.; Louro, Sonia R. W.; Beraldo, Heloisa

    2009-07-01

    The copper(II) complexes [Cu(H2Am4DH)Cl 2] ( 1), [Cu(H2Am4Me)Cl 2] ( 2), [Cu(H2Am4Et)Cl 2] ( 3) and [Cu(2Am4Ph)Cl] ( 4) with 2-pyridineformamide thiosemicarbazone (H2Am4DH) and its N(4)-methyl (H2Am4Me), N(4)-ethyl (H2Am4Et) and N(4)-phenyl (H2Am4Ph) derivatives were studied by means of infrared and EPR spectral techniques. The crystal structure of 4 was determined. The studied compounds proved to be toxic to Artemia salina, suggesting that they could present cytotoxic activity against solid tumors. Among the free thiosemicarbazones H2Am4Ph presented higher toxicity than all other compounds, which showed comparable effects. In the case of complexes 2 and 3 toxicity is probably attributable to the complex as an entity or to a synergistic effect involving the thiosemicarbazone and copper. H2Am4Ph and complexes 2 and 3 revealed to be the most promising compounds as potential antineoplasic agents.

  6. Reporting a new siderophore based Ca(2+) selective chemosensor that works as a staining agent in the live organism Artemia.

    Science.gov (United States)

    Raju, M; Nair, Ratish R; Raval, Ishan H; Haldar, Soumya; Chatterjee, Pabitra B

    2015-11-21

    A Ca(2+)-specific chemosensor involving acyclic non-ether and non-carboxylato-type metal chelating ligands is rare. The tetradentate OONO artificial receptor, HL, possessing a sulfur-containing intermediate siderophore aeruginic acid, tethered to a rhodamine 6G based signalling unit in a single molecule has been synthesized. The fluoroionophore required excitation in the visible wavelength (510 nm) and showed highly selective and sensitive detection of Ca(2+) ions in 100% water solution in HEPES buffer at physiological pH (7.4). The probe HL, with LOD as low as 70 nM, behaves reversibly and showed nearly 17-fold enhanced selectivity for Ca(2+) over other cell abundant alkali and alkaline metal ions such as Na(+), K(+), Li(+), and Mg(2+) without any intervention. Job's plot, (1)H NMR titration and ESI-MS data provided corroborative evidence in support of 1 : 1 association between HL and Ca(2+). From a wide range of transition and heavy metal ions series, HL also binds Cu(2+). However, the use of l-cysteine removes the interference from Cu(2+) and results in highly selective detection specificity of HL for Ca(2+). As a reversible "off-on-off" fluorescent chemosensor, it is possible to detect Ca(2+) at as low as 5 μM in the midgut region of the gastrointestinal tract of the live animal Artemia, a brine shrimp. PMID:26460620

  7. Extratos de Moringa oleifera e Vernonia sp. sobre Candida albicans e Microsporum canis isolados de cães e gatos e análise da toxicidade em Artemia sp. Moringa oleifera and Vernonia sp. extracts against Candida albicans and Microsporum canis isolates from dogs and cats and analysis of toxicity to Artemia sp.

    Directory of Open Access Journals (Sweden)

    Marcos Fábio Gadelha Rocha

    2011-10-01

    screening for compounds with antifungal properties. Based on this, the present study investigated the antifungal potential of extracts of Baccharis ligustrina, B. schultzii, Croton jacobinensis, Licania rigida, Moringa oleifera, Vernonia sp. and V. brasiliana and of essential oils of Lippia alba (Chemotypes 1, 2, 3 and 4 and Ocimum gratissimum. Initially, a qualitative evaluation of the antifungal activity of each vegetal sample against strains of Candida albicans and Microsporum canis, through the agar diffusion method, was performed. Extracts of M. oleifera (MLF-C and Vernonia sp. (TVS-H presented activity against C. albicans and M. canis with inhibition halos =10mm. Then, minimum inhibitory concentrations (MICs for MLF-C and TVS-H against 12 strains of C. albicans and M. canis were determined through the methodology established by the Clinical and Laboratory Standards Institute (CLSI, and acute toxicity tests against Artemia sp. were performed for both extracts. MICs (80% for MLF-C and TVS-H varied from 0.156 to 2.5mg mL-1 against C. albicans and from 0.039 to 1.25mg mL-1 and 0.039 to 0.625mg mL-1 against M. canis, respectively. MICs (100% for MLF-C and TVS-H varied from 0.625 to 2.5mg mL-1 for C. albicans and from 0.039 to 2.5mg mL-1 and 0.078 to 1.25mg mL-1 against M. canis, respectively. Lethal doses (DL50 of MLF-C and TVS-H were 201.09 and 204.17mg mL-1, respectively, being, therefore, demonstrated the low toxicity of these extracts. M. oleifera and Vernonia sp. extracts presented in vitro antifungal activity against C. albicans and M. canis, creating perspectives for the development of studies on the characterizations of their bioactive components.

  8. Evaluation of Toxic, Cytotoxic, Mutagenic, and Antimutagenic Activities of Natural and Technical Cashew Nut Shell Liquids Using the Allium cepa and Artemia salina Bioassays

    OpenAIRE

    Aracelli de Sousa Leite; Alisson Ferreira Dantas; George Laylson da Silva Oliveira; Gomes Júnior, Antonio L.; Sidney Gonçalo de Lima; Antônia Maria das Graças Lopes Citó; de Freitas, Rivelilson M.; Melo-Cavalcante, Ana Amélia de C.; José Arimateia Dantas Lopes

    2015-01-01

    The cashew nut releases a substance that is known as cashew nut shell liquid (CNSL). There are both natural (iCNSL) and technical (tCNSL) cashew nut shell liquids. This study used an Artemia salina bioassay to evaluate the toxic effects of iCNSL and tCNSL cashew nut shell liquids. It also evaluated the toxicity, cytotoxicity, and mutagenicity of CNSL and its effects on the damage induced by copper sulfate (CuSO4·5H2O) on the meristems’ root of Allium cepa. Effects of the damage induced by CuS...

  9. Contributions towards a specific DHA enrichment in the live food Brachionus plicatilis and Artemia sp.

    OpenAIRE

    Dhert, Ph.; Sorgeloos, P.; Devresse, B.

    1993-01-01

    This paper reports on enrichment techniques oriented towards a specific DHA accumulation in the live prey Brachionus plicatilis and Artemia sp. The product used in these experiments (DHA7) is an experimental emulsion with a DHA/EPA ratio 6.7:1. Rotifers enriched with this pure DHA7 emulsion contained up to 69 mg/g DW DHA and a DHA/EPA ratio of 1.6. The DHA/EPA ration could be increased to a much higher level by different enrichment techniques. Dilution of the DHA7 emulsion with coconut oil pr...

  10. Evaluation of toxic effects with transition metal ions, EDTA, SBTI and acrylic polymers on Aedes aegypti (L., 1762 (Culicidae and Artemia salina (Artemidae

    Directory of Open Access Journals (Sweden)

    Eduardo José de Arruda

    2011-06-01

    Full Text Available This work aimed to evaluate the toxicity of some insecticides compounds on Aedes aegypti and Artemia salina larvae. Bioassays were carried out to evaluate the toxic effect after of 24 and 72 h using the compounds or associations. The LC10, LC50 and LC90 values were obtained and utilized for toxicity comparations. For Ae. aegypti, LC50 were 32.65 mg L-1 in 24 h for Na2[EDTA-Cu(II] and total mortality in 72 h for SAP-Na2[EDTA-Cu(II].

  11. Optimización del enriquecimiento de nauplios de Artemia mediante el uso de emulsiones lipídicas formuladas a partir de aceites sintéticos ricos en DHA

    OpenAIRE

    Viciano Delibano, Elena

    2015-01-01

    Los nauplios de Artemia se utilizan como presa viva en criaderos de organimos marinos de todo el mundo debido a su disponibilidad y digestibilidad, pero su valor nutricional no se ajusta a las demandas o necesidades de las larvas de peces, moluscos o crustáceos marinos, ya que carecen de los ácidos grasos esenciales (EFA, Essential Fatty Acids) para estos organismos. Por tanto, es indispensable llevar a cabo un enriquecimiento de los nauplios de Artemia. El enriquecimiento consiste en incubac...

  12. Mestizaje y globalización en la arquitectura en Filipinas. Obando y Los Baños, dos casos de iglesias franciscanas de la segunda mitad del siglo XVIII

    Directory of Open Access Journals (Sweden)

    Luengo Gutiérrez, Pedro

    2014-06-01

    Full Text Available The Franciscan presence around Manila had a high architectonic relevance during the second half of the eighteenth century. Recently two new drawings of that time have been found in AFIO. They are plans of the Church of Virgen de Salambao (1765 and that of Los Baños (1782. The Franciscan constitutions had a special attention to architecture, therefore specific solutions were proposed, affecting later works.La presencia de los franciscanos en los alrededores de Manila tuvo una gran relevancia arquitectónica durante la segunda mitad del siglo XVIII. Recientemente se han localizado en el AFIO dos nuevos dibujos de esta fecha. Se trata de los croquis de la ermita de la Virgen de Salambao (1765 y de la iglesia de Los Baños (1782. Las constituciones franciscanas tenían especial cuidado con la arquitectura, lo que obligó a plantear soluciones concretas que afectarían más tarde a otras obras.

  13. Substituição de Artemia sp. pelo rotífero Brachionus plicatilis na larvicultura do camarão-d'água-doce (Macrobrachium rosenbergii De Man, 1879 Replacement of the Artemia sp. for the rotifer Brachionus plicatilis in the hatchering of the freshwater prawn (Macrobrachium rosenbergii De Man, 1879

    Directory of Open Access Journals (Sweden)

    Luciana Almada Thomaz

    2004-12-01

    Full Text Available Conduziu-se o presente trabalho com o objetivo de avaliar o efeito da substituição dos náuplios de Artemia sp. pelo rotífero enriquecido e congelado (Brachionus plicatilis, O.F. Müller, 1786 sobre a sobrevivência e peso seco das larvas. O experimento foi conduzido em blocos casualizados, sendo testados quatro regimes alimentares na larvicultura do camarão M. rosenbergii, com quatro repetições por tratamento. Nos regimes alimentares, realizaram-se substituições progressivas de náuplios de Artemia sp. (nas pelo rotífero Brachionus plicatilis (rots e testaram-se os seguintes tratamentos: 100% B. plicatilis (30 rots/mL (T1; 100% Artemia sp. (5 nas/mL (T2, 60% Artemia sp. (3 nas/mL + 40% B. plicatilis (12 rots/mL (T3 e 40% Artemia sp. (2 nas/mL + 60% B. plicatilis (18 rots/mL (T4, adicionando-se a estes tratamentos ração úmida. Os resultados da sobrevivência final em pós-larvas foram analisados pelo teste do X² e demonstraram não haver diferenças significativas do tratamento T2 (68,36% sobre os tratamentos T3 (68,76% e T4 (64,60%. O tratamento T1 (100% B. plicatilis apresentou mortalidade total no 14º dia do experimento. O peso seco médio das pós-larvas foi analisado estatisticamente pela ANOVA, não apresentando diferenças significativas entre os valores de 3,29 mg (T2, 3,08 mg (T3 e 3,38 mg (T4. A taxa de mortalidade baseada no número de larvas encontradas mortas diariamente, em relação ao número de larvas estocadas inicialmente, foi maior para todos os tratamentos nos primeiros 15 dias do experimento. Portanto, os resultados demonstraram que a substituição total de rotíferos enriquecidos e congelados acarretou a mortalidade total das larvas, mas a substituição parcial de 40% e 60% dos náuplios de Artemia sp. pelo B. plicatilis foi viável, não apresentando prejuízos significativos em termos de sobrevivência e peso seco das pós-larvas.This work was carried out to identify the replacement of the nauplii Artemia

  14. Masculinización del cíclido nativo Tenhuayaca, Petenia splendida (Günther, 1862, usando nauplios de Artemia como vehículo del esteroide 17-α metiltestosterona Mazculinization of the native cichlid Tenhuayaca, Petenia splendida (Günther, 1862, using Artemia nauplii as vehicle of the steroid 17-α methyltestosterone

    Directory of Open Access Journals (Sweden)

    Juan Manuel Vidal-López

    2009-12-01

    Full Text Available El uso de esteroides para producir poblaciones monosexo en cíclidos, ha sido ampliamente utilizado con el objetivo de evitar el proceso de reproducción y sobrepoblación de los estanques de cultivo, por medio de su aplicación a través del alimento balanceado. Sin embargo, cíclidos como la tenhuayaca, la cual tiene un alto potencial acuícola en el sureste de México y Centroamérica, durante su fase larvaria no aceptan el alimento balanceado, por lo que el uso de Artemia como vehículo para la administración de esteroides sintéticos ha sido propuesto recientemente. En el presente estudio se evaluó la masculinización de crías de Petenia splendida mediante la utilización de nauplios de Artemia como vehículo del esteroide 17-α metiltestosterona (MT, para lo cual se utilizaron larvas de primera alimentación a las cuales se les suministraron nauplios de Artemia como vehículo de la MT durante 5, 10, 20, 28, 45 y 60 días de alimentación, respectivamente y un tratamiento sin MT. Se determinó que los mayores porcentajes de masculinización y supervivencia, (96% de machos, 85% respectivamente se presentaron cuando se alimentaron las larvas con nauplios por 60 días. En el tratamiento control solamente se obtuvo un 56% de machos con una supervivencia de 83%, por lo cual concluimos que el uso de presas vivas como vehículo de la MT es adecuado para la producción de crías de P. splendida.At world-wide level the use of steroids to obtain all-male population in cichlids, has been widely used with the objective to avoid the reproduction process and to canalize the energy of the food in weight gain. In this sense, the application of steroids has been commonly through the artificial diets. Nevertheless, for some cichlid such as tenhuayaca or bay snook Petenia splendida, which is considered an appropriate species for aquaculture in the Southeastern of Mexico and Central America, the use of artificial diets during the larval period is not

  15. The effects of probiotic bacillus for promotion of growth and feeding parameters in beluga (Huso huso larvae via feeding by bioencapsulated Artemia

    Directory of Open Access Journals (Sweden)

    Hojatollah Jafaryan

    2010-12-01

    Full Text Available In this study five species of probiotic bacillus as bacterial blend under the commercial title ofProtexin aquatic were used for bioencapsulation of Artemia urmiana (Gunther, 1899. This experimentwas conducted in a completely random design. A. urmiana naupli I was used as a vector to carryprobiotic bacillus to digestive tract of Huso huso (Linnaeus, 1758 larvae. Nauplii with threeconcentrations of bacteria, 1×105, 2×105 and 3×105 bacteria per milliliter in suspension of broth for 10hours were bioencapsulated and beluga larvae were fed by them. Beluga larvae were fed 50 percent oftheir body weight for 6 times a day. The control treatment was fed by unbioencapsulated artemia nauplii.The results indicated that the probiotic bacillus could influence on growth and feeding parameters inbeluga larvae. The final body weight and specific growth rate (SGR for weight in experimentaltreatments had significant difference in comparison to control treatment (P0.05. In experimentaltreatments the Food efficiency was increased significantly in comparison with control. The probioticbacillus had significant positive effects on conversion efficiency ratio (CER, Daily growth coefficient(DGC and average weight gain (AWG in comparison to control treatment (P-1 significantly increased (P<0.05.

  16. Potencial toxicológico frente Artemia Salina em plantas condimentares comercializadas no município de Campina Grande-PB

    Directory of Open Access Journals (Sweden)

    Emmanuel Moreira Pereira

    2015-03-01

    Full Text Available O conhecimento do potencial toxicológico das plantas é um fator primordial para estipular o limite consumível. Objetivou-se nesse trabalho avaliar o potencial toxicológico de plantas condimentares frente Artemia salina, expostas às concentrações dos extratos das plantas erva-doce (Pimpinella anisum L., pimenta malagueta (Capsicum frutescens, endro (Anethum graveolens L. e alecrim (Rosmarinus officinalis L.. O trabalho foi desenvolvido no Laboratório de Engenharia de Alimentos - LEA pertencente ao Centro de Tecnologia e Recursos Naturais da Universidade Federal de Campina Grande-PB. A erva doce apresentou uma baixa toxicidade, atingindo uma DL50 de 428ppm do extrato. Já a pimenta malagueta exibiu um comportamento similar, atingindo o seu potencial toxicológico máximo na terceira diluição com DL50 716,1ppm. Para o endro, observou-se uma baixa taxa de mortalidade, consequentemente foi considerada não toxica, apresentando a DL50, com 2.624,5ppm. O alecrim apresentou baixos percentuais de mortalidade em náuplios de Artemia, sendo a DL50 com 3.720,6ppm, sendo considerado não toxico. No entanto necessita-se de estudos mais aprofundados para caracterizar a composição química das plantas estudadas e um teste in vivo para as que apresentaram baixa toxicidade.

  17. Composição química, atividade antibacteriana in vitro e toxicidade em Artemia salina do óleo essencial das inflorescências de Ocimum gratissimum L., Lamiaceae Chemical composition, antibacterial activity in vitro and brine-shrimp toxicity of the essential oil from inflorescences of Ocimum gratissimum L., Lamiaceae.

    Directory of Open Access Journals (Sweden)

    Lenise L. Silva

    2010-11-01

    Full Text Available O óleo essencial das inflorescências de Ocimum gratissimum L., Lamiaceae foi obtido por hidrodestilação e analisado por CG/EM. Os constituintes majoritários identificados foram eugenol (81,94% e γ-muuroleno (12,58%. O óleo essencial das inflorescências demonstrou atividade antibacteriana frente a todas as cepas bacterianas testadas pelo método de microdiluição em caldo. Merece destaque a atividade verificada frente às cepas resistentes de Enterococcus faecalis, Staphylococcus aureus e Escherichia coli. Os valores obtidos de concentração inibitória mínima (CIM e a concentração bactericida mínima (CBM variaram, respectivamente, entre 0,5-2 mg/mL e 1-4 mg/mL. Valores de CL50 de 233,8 (200,7-272,0 µg/mL para o óleo essencial e 186,1 (144,1-228,5 µg/mL para o eugenol, utilizado como controle positivo, foram observados frente à Artemia salina L.The essential oil obtained by hydrodistillation of the inflorescences of Ocimum gratissimum L. was analyzed by GC/MS. The main constituents were eugenol (81.94% and γ-muurolene (12.58%. Antibacterial activity was shown against all assayed strains by the broth microdilution method. It's worth noting the activity against resistant strains of Enterococcus faecalis, Staphylococcus aureus and Escherichia coli. Minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC values ranged between 0.5-2 mg/mL and 1-4 mg/mL, respectively. Preliminary toxicity assayed by the brine-shrimp (Artemia salina L. test showed LC50 values of 233.8 (200.7 - 272.0 µg/mL and 186.1 (144.1 - 228.5 µg/mL, respectively for the essential oil and eugenol (positive control.

  18. COMPARISON OF COLD TOLERANCE AMONG DIFFERENT ARTEMIA STRAINS%不同品系卤虫耐寒力的比较

    Institute of Scientific and Technical Information of China (English)

    贾沁贤; 陈立靖; 左中原

    1999-01-01

    采用正交设计实验方法建立了卤虫耐寒力的测试条件,并依据无节幼虫、幼虫和成虫的死亡率比较了来源于中国、美国和墨西哥等地的16个地理品系的耐寒力.主要结果为:1.幼虫的培养温度和盐度条件对其耐寒力有显著影响,在成虫仅盐度有较为显著影响,而孵化盐度和温度对无节幼虫耐寒力的影响不显著;2.在三种虫态中,无节幼虫的耐寒力最强,其次为成虫,幼虫期卤虫对低温最敏感;3.各品系间耐寒力差异较大,这16个品系中三种虫态的变化趋向也不尽一致,比较而言,美国旧金山湾品系、墨西哥Texcoco和Sonora Yavaros两个品系以及中国山东沿海的埕口和羊口等品系耐寒力相对较强,而中国内陆的小柴旦湖、宁夏盐池、山西盐池、新疆巴里坤等4个品系的耐寒力较弱.讨论了卤虫耐寒力的生态学意义和中国沿海品系耐寒力不一致的原因.

  19. Outcome of EPIZONE Extension ON VER/VNN: Pathogenicity study of 10 betanodavirus strains with an in vivo challenge in European sea bass (Dicentrarchus labrax)

    DEFF Research Database (Denmark)

    Vendramin, Niccolò; Toffan, A.; Cappellozza, E.;

    2012-01-01

    , is considered the most serious viral threat affecting marine farmed species in the Mediterranean region, thus representing one of the bottlenecks for further development of aquaculture industry. Epidemiological investigations carried out in different geographical areas demonstrated that Betanodavirus can...... be detected in wild fish as well as other aquatic organisms (artemia, rotifers, molluscs and crustaceans) in addition to farmed fish. The RGNNV genotype is the most widespread in the Mediterranean region, nevertheless some strains, characterized by containing genetic material belonging to both the RGNNV...

  20. The Cytotoxicity Study of Carboxymethyl Starch (CMS) of Sago Starch (Metro xylon sago) by Brine Shrimp Lethality Test (Artemia salina nauplii)

    International Nuclear Information System (INIS)

    CMS can be produced by substitution of the hydroxyl groups with sodium monochloroacetate in the presence of strong alkali. Carboxy methylation can be performed in water as a solvent or in a water-miscible organic solvent containing a small amount of water such as ethanol, isopropanol, methanol or toluene. The use of organic solvent will preserve the final product in the granular form and the side product can be washed out easily but some of them may be having potential toxicity and carcinogenic effect. In this study, CMS was investigated the level of toxicity by using brine shrimp lethality (BSLT). Brine shrimp test method was used to screen CMS for their biological activity. The screening results showed that the LC50, of CMS is more than 100 mg/ ml dose concentration. In conclusion, CMS is not cytotoxicity to Artemia salina nauplii and BSLT method is simple, inexpensive and convenient assay for the detection of cytotoxic compound. (author)

  1. The efficiency of a new hydrodynamic cavitation pilot system on Artemia salina cysts and natural population of copepods and bacteria under controlled mesocosm conditions.

    Science.gov (United States)

    Cvetković, Martina; Grego, Mateja; Turk, Valentina

    2016-04-15

    A study of the efficiency of hydrodynamic cavitation and separation was carried out to evaluate an innovative, environmentally safe and acceptable system for ballast water treatment for reducing the risk of introducing non-native species worldwide. Mesocosm experiments were performed to assess the morphological changes and viability of zooplankton (copepods), Artemia salina cysts, and the growth potential of marine bacteria after the hydrodynamic cavitation treatment with a different number of cycles. Our preliminary results confirmed the significant efficiency of the treatment since more than 98% of the copepods and A. salina cysts were damaged, in comparison with the initial population. The efficiency increased with the number of the hydrodynamic cavitation cycles, or in combination with a separation technique for cysts. There was also a significant decrease in bacterial abundance and growth rate, compared to the initial number and growth potential. PMID:26902683

  2. Effects of administration of probiotic strains on GALT of larval gilthead seabream: Immunohistochemical and ultrastructural studies.

    Science.gov (United States)

    Picchietti, Simona; Mazzini, Massimo; Taddei, Anna Rita; Renna, Raffaella; Fausto, Anna Maria; Mulero, Victoriano; Carnevali, Oliana; Cresci, Alberto; Abelli, Luigi

    2007-01-01

    Two bacterial strains Lactobacillus fructivorans (AS17B), isolated from adult seabream (Sparus aurata L.) gut, and Lactobacillus plantarum (906), isolated from human faeces, were administered contemporaneously during seabream development using Brachionus plicatilis and/or Artemia salina and dry feed as vectors. Experimental group A received the probiotic strains already via rotifers from day 5 post-hatch (ph), whereas treatment of group B began with Artemia feeding from day 27 ph. Fish were sampled at day 28 ph (group A and control) and day 99 ph (groups A, B and control) for electron microscopy, histology and immunohistochemistry with the polyclonal antiserum ORa against homologous serum Ig and the mAb G7 specific for seabream acidophilic granulocytes. In all groups, timing and pattern of differentiation of the digestive tract did not differ. Furthermore, neither tissue damage nor manifest inflammation was provoked by probiotic administration. At day 28 ph, the developing GALT already housed mucosal leucocytes, including Ig(+) cells but no acidophilic granulocytes. No differences were seen between experimental groups. At day 99 ph, the density of Ig(+) cells (+51%) and acidophilic granulocytes (+284%) was significantly higher (p<0.05) in group A than in controls. Also group B had a higher density of Ig(+) cells (+17%) and acidophilic granulocytes (+130%) compared with controls, although less pronounced. Light and electron microscopy observations detailed the occurrence of heterogeneous populations of lymphocytes and granulocytes in the developing intestinal mucosa, and highlighted the net expansion of G7(+) acidophilic granulocytes (A +536%, B +292% vs. control) due to probiotic administration. Evidence is provided that early feeding with probiotic-supplemented diet increased the number of Ig(+) cells and acidophilic granulocytes in seabream gut and that the effects were more pronounced when administration started during gut metamorphosis. These results point to a

  3. High surface adsorption properties of carbon-based nanomaterials are responsible for mortality, swimming inhibition, and biochemical responses in Artemia salina larvae

    Energy Technology Data Exchange (ETDEWEB)

    Mesarič, Tina, E-mail: tina.mesaric84@gmail.com [Department of Biology, Biotechnical Faculty, University of Ljubljana (Slovenia); Gambardella, Chiara, E-mail: chiara.gambardella@ge.ismar.cnr.it [Institute of Marine Sciences, National Research Council, Genova (Italy); Milivojević, Tamara, E-mail: milivojevictamara@gmail.com [Department of Biology, Biotechnical Faculty, University of Ljubljana (Slovenia); Faimali, Marco, E-mail: marco.faimali@ismar.cnr.it [Institute of Marine Sciences, National Research Council, Genova (Italy); Drobne, Damjana, E-mail: damjana.drobne@bf.uni-lj.si [Department of Biology, Biotechnical Faculty, University of Ljubljana (Slovenia); Centre of Excellence in Nanoscience and Nanotechnology (CO Nanocentre), Ljubljana (Slovenia); Centre of Excellence in Advanced Materials and Technologies for the Future (CO NAMASTE), Ljubljana (Slovenia); Falugi, Carla, E-mail: carlafalugi@hotmail.it [Department of Earth, Environment and Life Sciences, University of Genova, Genova (Italy); Makovec, Darko, E-mail: darko.makovec@ijs.si [Jožef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia); Jemec, Anita, E-mail: anita.jemec@bf.uni-lj.si [Department of Biology, Biotechnical Faculty, University of Ljubljana (Slovenia); Sepčić, Kristina, E-mail: kristina.sepcic@bf.uni-lj.si [Department of Biology, Biotechnical Faculty, University of Ljubljana (Slovenia)

    2015-06-15

    Highlights: • Carbon-based nanomaterials adsorb onto the body surface of A. salina larvae. • Surface adsorption results in concentration–dependent inhibition of larval swimming. • Carbon-based nanomaterials induce no significant mortality of A. salina larvae. - Abstract: We investigated the effects of three different carbon-based nanomaterials on brine shrimp (Artemia salina) larvae. The larvae were exposed to different concentrations of carbon black, graphene oxide, and multiwall carbon nanotubes for 48 h, and observed using phase contrast and scanning electron microscopy. Acute (mortality) and behavioural (swimming speed alteration) responses and cholinesterase, glutathione-S-transferase and catalase enzyme activities were evaluated. These nanomaterials were ingested and concentrated in the gut, and attached onto the body surface of the A. salina larvae. This attachment was responsible for concentration–dependent inhibition of larval swimming, and partly for alterations in the enzyme activities, that differed according to the type of tested nanomaterials. No lethal effects were observed up to 0.5 mg/mL carbon black and 0.1 mg/mL multiwall carbon nanotubes, while graphene oxide showed a threshold whereby it had no effects at 0.6 mg/mL, and more than 90% mortality at 0.7 mg/mL. Risk quotients calculated on the basis of predicted environmental concentrations indicate that carbon black and multiwall carbon nanotubes currently do not pose a serious risk to the marine environment, however if uncontrolled release of nanomaterials continues, this scenario can rapidly change.

  4. Evaluation of toxic, cytotoxic, mutagenic, and antimutagenic activities of natural and technical cashew nut shell liquids using the Allium cepa and Artemia salina bioassays.

    Science.gov (United States)

    Leite, Aracelli de Sousa; Dantas, Alisson Ferreira; Oliveira, George Laylson da Silva; Gomes Júnior, Antonio L; de Lima, Sidney Gonçalo; Citó, Antônia Maria das Graças Lopes; de Freitas, Rivelilson M; Melo-Cavalcante, Ana Amélia de C; Dantas Lopes, José Arimateia

    2015-01-01

    The cashew nut releases a substance that is known as cashew nut shell liquid (CNSL). There are both natural (iCNSL) and technical (tCNSL) cashew nut shell liquids. This study used an Artemia salina bioassay to evaluate the toxic effects of iCNSL and tCNSL cashew nut shell liquids. It also evaluated the toxicity, cytotoxicity, and mutagenicity of CNSL and its effects on the damage induced by copper sulfate (CuSO4·5H2O) on the meristems' root of Allium cepa. Effects of the damage induced by CuSO4·5H2O were evaluated before (pre-), during (co-), and after (post-) treatments. The iCNSL contained 94.5% anacardic acid, and the tCNSL contained 91.3% cardanol. The liquids were toxic to A. salina. Toxicity, cytotoxicity, and mutagenicity were observed with iCNSL compared with the negative control. Similarly, iCNSL failed to inhibit the toxicity and cytotoxicity of CuSO4·5H2O. The tCNSL was not toxic, cytotoxic, or mutagenic in any of the concentrations. However, the lowest iCNSL concentrations and all of the tCNSL concentrations had preventive, antimutagenic, and reparative effects on micronuclei and on chromosomal aberrations in the A. cepa. Therefore, protective, modulating, and reparative effects may be observed in the A. cepa, depending on the concentration and type of CNSL used. PMID:25861638

  5. High surface adsorption properties of carbon-based nanomaterials are responsible for mortality, swimming inhibition, and biochemical responses in Artemia salina larvae

    International Nuclear Information System (INIS)

    Highlights: • Carbon-based nanomaterials adsorb onto the body surface of A. salina larvae. • Surface adsorption results in concentration–dependent inhibition of larval swimming. • Carbon-based nanomaterials induce no significant mortality of A. salina larvae. - Abstract: We investigated the effects of three different carbon-based nanomaterials on brine shrimp (Artemia salina) larvae. The larvae were exposed to different concentrations of carbon black, graphene oxide, and multiwall carbon nanotubes for 48 h, and observed using phase contrast and scanning electron microscopy. Acute (mortality) and behavioural (swimming speed alteration) responses and cholinesterase, glutathione-S-transferase and catalase enzyme activities were evaluated. These nanomaterials were ingested and concentrated in the gut, and attached onto the body surface of the A. salina larvae. This attachment was responsible for concentration–dependent inhibition of larval swimming, and partly for alterations in the enzyme activities, that differed according to the type of tested nanomaterials. No lethal effects were observed up to 0.5 mg/mL carbon black and 0.1 mg/mL multiwall carbon nanotubes, while graphene oxide showed a threshold whereby it had no effects at 0.6 mg/mL, and more than 90% mortality at 0.7 mg/mL. Risk quotients calculated on the basis of predicted environmental concentrations indicate that carbon black and multiwall carbon nanotubes currently do not pose a serious risk to the marine environment, however if uncontrolled release of nanomaterials continues, this scenario can rapidly change

  6. Evaluation of Toxic, Cytotoxic, Mutagenic, and Antimutagenic Activities of Natural and Technical Cashew Nut Shell Liquids Using the Allium cepa and Artemia salina Bioassays

    Directory of Open Access Journals (Sweden)

    Aracelli de Sousa Leite

    2015-01-01

    Full Text Available The cashew nut releases a substance that is known as cashew nut shell liquid (CNSL. There are both natural (iCNSL and technical (tCNSL cashew nut shell liquids. This study used an Artemia salina bioassay to evaluate the toxic effects of iCNSL and tCNSL cashew nut shell liquids. It also evaluated the toxicity, cytotoxicity, and mutagenicity of CNSL and its effects on the damage induced by copper sulfate (CuSO4·5H2O on the meristems’ root of Allium cepa. Effects of the damage induced by CuSO4·5H2O were evaluated before (pre-, during (co-, and after (post- treatments. The iCNSL contained 94.5% anacardic acid, and the tCNSL contained 91.3% cardanol. The liquids were toxic to A. salina. Toxicity, cytotoxicity, and mutagenicity were observed with iCNSL compared with the negative control. Similarly, iCNSL failed to inhibit the toxicity and cytotoxicity of CuSO4·5H2O. The tCNSL was not toxic, cytotoxic, or mutagenic in any of the concentrations. However, the lowest iCNSL concentrations and all of the tCNSL concentrations had preventive, antimutagenic, and reparative effects on micronuclei and on chromosomal aberrations in the A. cepa. Therefore, protective, modulating, and reparative effects may be observed in the A. cepa, depending on the concentration and type of CNSL used.

  7. Geobacteraceae strains and methods

    Energy Technology Data Exchange (ETDEWEB)

    Lovley, Derek R.; Nevin, Kelly P.; Yi, Hana

    2015-07-07

    Embodiments of the present invention provide a method of producing genetically modified strains of electricigenic microbes that are specifically adapted for the production of electrical current in microbial fuel cells, as well as strains produced by such methods and fuel cells using such strains. In preferred embodiments, the present invention provides genetically modified strains of Geobacter sulfurreducens and methods of using such strains.

  8. Muscle strain (image)

    Science.gov (United States)

    A muscle strain is the stretching or tearing of muscle fibers. A muscle strain can be caused by sports, exercise, a ... something that is too heavy. Symptoms of a muscle strain include pain, tightness, swelling, tenderness, and the ...

  9. Muscle strain treatment

    Science.gov (United States)

    Treatment - muscle strain ... Question: How do you treat a muscle strain ? Answer: Rest the strained muscle and apply ice for the first few days after the injury. Anti-inflammatory medicines or acetaminophen ( ...

  10. Sustitución de Artemia por nematodos en la alimentación de postlarvas (PL 6 a PL 10 del camarón marino (Penaeus vannamei boone 1936

    Directory of Open Access Journals (Sweden)

    Gerardo Emigdio Palacios Martínez

    2016-03-01

    Full Text Available Con el fin de determinar la viabilidad de una cepa nativa de nemátodo en la alimentación de estados postlarvales avanzados (PL 6 – PL 10 de Penaeus vannamei, se realizó un experimento con tres regímenes alimenticios. En el primero se alimentaron postlarvas con un peso húmedo determinado de nauplios de Artemia, en el segundo se alimentó con la misma ración pero con nemátodos y en el tercero se alimentó con nemátodos con el doble de la ración. Al final de la prueba se comparó la calidad de las postlarvas analizando talla, sobrevivencia, desarrollo branquial, prueba de estrés y dispersión de talla, obteniéndose como resultado que las postlarvas alimentadas con Artemia tuvieron las mejores tallas (6,4 ± 0,8 mm y sobrevivencias promedio (89%, en comparación con el segundo (6,2 ± 0,8 mm y 75% y el tercer tratamiento (5,9 ± 0,7 mm y 69%. En las pruebas de desarrollo branquial y prueba de estrés no se observo ninguna diferencia significativa entre tratamientos. La dispersión de tallas en ninguno de los tratamientos superó el máximo límite fijado por CLIFFORD (1992 del 15%. Se concluye que la cepa nativa de nemátodo puede sustituir a la Artemia sp. en la alimentación de postlarvas (PL 6 a PL 10 del camarón P. vannamei.

  11. 拟穴青蟹大眼幼体对卤虫的摄食率和摄食选择%Feeding rates and foraging preference of Scylla paramamosain megalopae on Artemia sp

    Institute of Scientific and Technical Information of China (English)

    陈学雷; 陈思; 李少菁; 林琼武; 王桂忠

    2011-01-01

    研究了拟穴青蟹(Scylla paramamosain)大眼幼体在不同饵料密度和组合条件下对卤虫(Ar-temia sp.)无节幼体及成体的摄食率、摄食节律等,发现:光照-视觉因素对拟穴青蟹大眼幼体捕食卤虫无节幼体的数量无显著影响,但对捕食卤虫成体的影响显著(p)时,饵料密度与拟穴青蟹大眼幼体摄食率呈正相关;饵料密度较高时饵料密度变化对拟穴青蟹大眼幼体摄食率的影响不显著(p>0.05).禁食后投饵,在高饵料密度(如卤虫无节幼体密度≥10 incL/cm)下拟穴青蟹大眼幼体的摄食率在短时间(如4 h)较高,随供饵时间的延续摄食率开始下降,较长时间(24 h)摄食率显著较低.以干重计,拟穴青蟹大眼幼体对卤虫成体的摄食率全面高于对卤虫无节幼体;但混合投喂卤虫无节幼体和成体时拟穴青蟹大眼幼体摄食的卤虫成体数量较少,表明在卤虫无节幼体和成体同时存在的情况下拟穴青蟹大眼幼体倾向于放弃卤虫成体捕食无节幼体.拟穴青蟹大眼幼体的摄食行为受到被捕食风险和饵料斑块分布的显著影响.育苗生产中对拟穴青蟹大眼幼体投喂卤虫无节幼体的密度无需高于10 ind/cm.%Scylla paramamosain is distributed widely in Chinese and Southeast Asian coastal waters as an important commercial crustacean. Scylla paramamosain megalopae mainly feed on Artemia sp. nauplii and adults in aquaculture systems. This paper employs an experimental ecological method and energy measure to study the feeding rates,foraging preferences and foraging rhythms of Scylla paramamosain megalopae on Artemia sp. nauplii and adults under different food density and food combinations, and aims to improve the food efficiency for Scylla paramamosain megalopae in aquaculture systems. There are four findings to the study. ( 1 ) Visible-optical factors do not affect the foraging of Scylla paramamosain megalopae on Artemia sp. nauplii but do influence foraging on

  12. Bioatividade de três espécies vegetais nativas da Floresta Atlântica brasileira frente ao microcrustáceo Artemia salina

    Directory of Open Access Journals (Sweden)

    W.M Pompilho

    2014-09-01

    Full Text Available Este trabalho teve por objetivo a investigação fitoquímica e propriedades antioxidantes de extratos das folhas de Trigynaea oblongifolia Schltdl (Annonaceae, Ottonia frutescens Trel (Piperaceae, e Bathysa australis (St Hill Hooz (Rubiaceae, bem como avaliar, in vitro, a letalidade frente ao microcrustáceo Artemia salina Leach. Os extratos foram preparados por maceração em metanol 10% (p/v por sete dias, à temperatura ambiente. A atividade antioxidante dos extratos foi determinada pela metodologia que utiliza o radical estável DPPH. A toxicidade dos extratos foi avaliada frente ao microcrustáceo A. salina. Os extratos de O. frutescens e B. australis apresentaram as seguintes classes de metabólitos secundários: Alcalóides, Antraquinonas, Cumarinas, Polifenóis (Taninos, Saponinas. Nos extratos de T. oblongifolia, além dos metabólitos citados anteriormente, foi detectada a presença de Flavonóides. A atividade antioxidante, observada em 30 minutos na concentração de 24 µg/mL de extrato, foi de: O. frutescens - 38,3%, T. oblongifolia - 32,3%, e B. australis - 32,1%. A Concentração Letal, CL50, dos extratos em A. salina foi de: O. frutescens - 149,75 ± 1,02 µg/mL, T. oblongifolia - 148,8 ± 1,74 µg/mL, e B. australis - 684 ± 9,04 µg/mL. Neste contexto, destacamos as espécies, nativas da Floresta Atlântica, O. frutescens e T. oblongifolia de grande potencial na bioprospecção de moléculas biologicamente ativas.

  13. Bioensayo General de Letalidad en Artemia Salina, a Las Fracciones del Extracto Etanólico De Psidium Guajava. L y Psidium Guineense. Sw

    Directory of Open Access Journals (Sweden)

    Lizbeth Sánchez

    2005-10-01

    Full Text Available El estudio se centró en la evaluación y verificación de la letalidad de las fracciones acetato de etilo, obtenida de los extractos etanólicos de los frutos en estado de madurez, verde y pintón, utilizando la cáscara y pulpa de las especies guayaba (Psidium guajava L y Choba (Psidium guineense Sw. La valoración se llevó a cabo mediante el bioensayo en Artemia salina, a través del cual, se evidencia el siguiente proceso: determinar la concentración letal 50 (CL50 utilizando el medio artificial a Ph 7-8, burbujear con el fin de saturar de oxígeno la solución, controlar la eclosión de los huevos a 25 °C despuésde 48 horas, preparar la solución madre y las de trabajo a concentraciones de 1500, 1000, 500,100, 10 g/ml, control positivo estricnina a 80, 70, 60, 50 g/ml, blanco solvente etanol a 80 g/ml. El ensayo biológico se realizó siguiendo las metodologías propuestas por Gualdrón, R (1994; Cyted (1995;Martínez, C (1999 y McLaughlin, J (1997. Comprobada la letalidad de las fracciones acetato del extracto etanólico de Psidium guajava. L y Psidium guineense. Sw mostró CL50 de 181.4 y 221.30g/ml respectivamente, los resultados se evaluaron según Gautret (2000.

  14. Cloning and expression of retinoblastoma-binding protein 4 gene in embryo diapause termination and in response to salinity stress from brine shrimp Artemia sinica.

    Science.gov (United States)

    Wang, Xiaolu; Yao, Feng; Liang, Xiaoyu; Zhu, Xiaolin; Zheng, Ren; Jia, Baolin; Hou, Lin; Zou, Xiangyang

    2016-10-15

    Retinoblastoma binding protein 4 (RBBP4) is a nuclear protein with four WD-repeat sequences and thus belongs to a highly conserved subfamily of proteins with such domains. This retinoblastoma-binding protein plays an important role in nucleosome assembly and histone modification, which influences gene transcription and regulates cell cycle and proliferation. Artemia sinica (brine shrimp) undergoes an unusual diapause process under stress conditions of high salinity and low temperature. However, the role of RBBP4 in diapause termination of embryo development in A. sinica remains unknown. Here, the full-length cDNA of the As-rbbp4 gene was obtained from A. sinica and found to contain 1411 nucleotides, including a 1281 bp open reading frame (ORF), 63 bp 5'-untranslated region (UTR) and a 67-bp 3'-UTR, which encodes a 427 amino acid (48 kDa) protein. Bioinformatic analysis indicated As-RBBP4 to be mainly located in the nucleus, with a theoretical isoelectric point of 4.79. Protein sequence domain analysis showed that As-RBBP4 is a conserved protein, especially in the WD40 domain. No specificity in expression of this gene was observed in tissues or organs by in situ hybridization. Real-time quantitative PCR and Western blot analyses of As-RBBP4 gene and protein expression, respectively, showed notably high levels at 10 h and a subsequent downward trend. Obvious trends in upregulation of As-RBBP4 were observed under conditions of low temperature and high salinity stress. As-E2F1 and As-CyclinE also presented similar trends as that of As-RBBP4 in Western blots. Analysis of the RBBP4 expression in early embryonic development of A. sinica indicated that this protein plays an important role in diapause termination and cell cycle regulation. PMID:27267406

  15. Program Calibrates Strain Gauges

    Science.gov (United States)

    Okazaki, Gary D.

    1991-01-01

    Program dramatically reduces personnel and time requirements for acceptance tests of hardware. Data-acquisition system reads output from Wheatstone full-bridge strain-gauge circuit and calculates strain by use of shunt calibration technique. Program nearly instantaneously tabulates and plots strain data against load-cell outputs. Modified to acquire strain data for other specimens wherever full-bridge strain-gauge circuits used. Written in HP BASIC.

  16. Comparative study of the assay of Artemia salina L. and the estimate of the medium lethal dose (LD50 value) in mice, to determine oral acute toxicity of plant extracts.

    Science.gov (United States)

    Logarto Parra, A; Silva Yhebra, R; Guerra Sardiñas, I; Iglesias Buela, L

    2001-09-01

    Artemia salina L. (Artemiidae), the brine shrimp larva, is an invertebrate used in the alternative test to determine toxicity of chemical and natural products. In this study the Medium Lethal Concentrations (LC50 value) of 20 plant extracts, Aloe vera (L.) Burm. F. (Aloeaceae), Artemisia absinthium L. (Asteraceae); Citrus aurantium L. (Rutaceae); Cymbopogon citratus (DC. Ex Nees) Stapf (Poaceae); Datura stramonium L. (Solanaceae); Justicia pectoralis Jacq. (Acanthaceae); Musa x paradisiaca L. (Musaceae); Ocimum basilicum L.; O. gratissimum L.; O. tenuiflorum L. (Lamiaceae); Pimenta dioica (L.) Merr. (Myrtaceae); Piper auritum Kunth (Piperaceae); Plantago major L. (Plantaginaceae); Plectranthus amboinicus (Lour.) Spreng. (Lamiaceae); Ruta graveolens L. (Rutaceae); Senna alata (L.) Roxb. (Fabaceae); Stachytarpheta jamaicensis (L.) Vahl (Verbenaceae); and Thuja occidentalis L. (Cupressaceae), were determined using Artemia salina L. (Artemiidae), with the objective of relating the results to the LD50 values reported in mice (tested at three concentrations: 10, 100, and 1000 microg/mL, for each extract). We found good correlation between the in vivo and the in vitro tests (r = 0.85 p < 0.05), and this method is a useful tool for predicting oral acute toxicity in plant extracts.

  17. Comparative study of the assay of Artemia salina L. and the estimate of the medium lethal dose (LD50 value) in mice, to determine oral acute toxicity of plant extracts.

    Science.gov (United States)

    Logarto Parra, A; Silva Yhebra, R; Guerra Sardiñas, I; Iglesias Buela, L

    2001-09-01

    Artemia salina L. (Artemiidae), the brine shrimp larva, is an invertebrate used in the alternative test to determine toxicity of chemical and natural products. In this study the Medium Lethal Concentrations (LC50 value) of 20 plant extracts, Aloe vera (L.) Burm. F. (Aloeaceae), Artemisia absinthium L. (Asteraceae); Citrus aurantium L. (Rutaceae); Cymbopogon citratus (DC. Ex Nees) Stapf (Poaceae); Datura stramonium L. (Solanaceae); Justicia pectoralis Jacq. (Acanthaceae); Musa x paradisiaca L. (Musaceae); Ocimum basilicum L.; O. gratissimum L.; O. tenuiflorum L. (Lamiaceae); Pimenta dioica (L.) Merr. (Myrtaceae); Piper auritum Kunth (Piperaceae); Plantago major L. (Plantaginaceae); Plectranthus amboinicus (Lour.) Spreng. (Lamiaceae); Ruta graveolens L. (Rutaceae); Senna alata (L.) Roxb. (Fabaceae); Stachytarpheta jamaicensis (L.) Vahl (Verbenaceae); and Thuja occidentalis L. (Cupressaceae), were determined using Artemia salina L. (Artemiidae), with the objective of relating the results to the LD50 values reported in mice (tested at three concentrations: 10, 100, and 1000 microg/mL, for each extract). We found good correlation between the in vivo and the in vitro tests (r = 0.85 p < 0.05), and this method is a useful tool for predicting oral acute toxicity in plant extracts. PMID:11695884

  18. Strains and Sprains

    Science.gov (United States)

    ... ON THIS TOPIC Sports Medicine Center Preventing Children's Sports Injuries Computer-Related Repetitive Stress Injuries Knee Injuries Broken ... Knee Injuries Sports and Exercise Safety Dealing With Sports Injuries Groin Strain Ankle Sprains Strains and Sprains Stretching ...

  19. Strained Silicon Photonics

    OpenAIRE

    Wehrspohn, Ralf B; Jörg Schilling; Christian Bohley; Clemens Schriever

    2012-01-01

    A review of recent progress in the field of strained silicon photonics is presented. The application of strain to waveguide and photonic crystal structures can be used to alter the linear and nonlinear optical properties of these devices. Here, methods for the fabrication of strained devices are summarized and recent examples of linear and nonlinear optical devices are discussed. Furthermore, the relation between strain and the enhancement of the second order nonlinear susceptibility is inves...

  20. 高原盐湖盐藻和卤虫资源的开发和利用%Development and Utilization of Salt Algae (Dunaliella salina) and Brine Shrimp (Artemia spp.) in the Plateau Salt Lake of China

    Institute of Scientific and Technical Information of China (English)

    印象初; 印红; 周可新; 张道川; 施鉴屏

    2001-01-01

    叙述了我国高原盐湖的名称、地理位置、面积、水深、海拔和盐湖类型等基本情况;盐湖中盐藻和卤虫的种类、生物学和生态学特性。并对它们的经济价值和开发利用作了初步的讨论。%In the paper, the name, geographical position, area, depth ofwater, altitude, brine type of salt lake from Plateau; ecology, biology and economy of salt algae (Dunaliella salina) and brine shrimp (Artemia spp.) are described. The development and utilization of the sources of salt lake are preliminarily discussed.

  1. Diffraction tomography of strain

    OpenAIRE

    Lionheart, W R B; Withers, P. J.

    2015-01-01

    We consider whether it is possible to recover the three dimensional strain field tomographically from neutron and x-ray diffraction data for polycrystalline materials. We show that the distribution of strain transverse to a ray cannot be deduced from one diffraction pattern accumulated along that path, but that a certain moment of that data corresponds to the transverse ray transform of the strain tensor and so may be recovered by inverting that transform given sufficient data. We show that t...

  2. Strained Silicon Photonics

    Directory of Open Access Journals (Sweden)

    Ralf B. Wehrspohn

    2012-05-01

    Full Text Available A review of recent progress in the field of strained silicon photonics is presented. The application of strain to waveguide and photonic crystal structures can be used to alter the linear and nonlinear optical properties of these devices. Here, methods for the fabrication of strained devices are summarized and recent examples of linear and nonlinear optical devices are discussed. Furthermore, the relation between strain and the enhancement of the second order nonlinear susceptibility is investigated, which may enable the construction of optically active photonic devices made of silicon.

  3. Strain-engineered MOSFETs

    CERN Document Server

    Maiti, CK

    2012-01-01

    Currently strain engineering is the main technique used to enhance the performance of advanced silicon-based metal-oxide-semiconductor field-effect transistors (MOSFETs). Written from an engineering application standpoint, Strain-Engineered MOSFETs introduces promising strain techniques to fabricate strain-engineered MOSFETs and to methods to assess the applications of these techniques. The book provides the background and physical insight needed to understand new and future developments in the modeling and design of n- and p-MOSFETs at nanoscale. This book focuses on recent developments in st

  4. Highly Strained Organophosphorus Compounds

    NARCIS (Netherlands)

    Slootweg, J.C.

    2005-01-01

    In our research on small, strained organophosphorus ring systems we became interested in the synthesis and applications of species that are even more strained than the parent phosphirane, by introducing an exocyclic double bond (methylenephosphirane), and by cyclopropyl spirofusion to the edge (e.g

  5. Isolation of TDA-producing Phaeobacter strains from sea bass larval rearing units and their probiotic effect against pathogenic Vibrio spp. in Artemia cultures

    DEFF Research Database (Denmark)

    Grotkjær, Torben; Bentzon-Tilia, Mikkel; D'Alvise, Paul;

    2016-01-01

    Fish-pathogenic Vibrio can cause large-scale crashes in marine larval rearing units and, since the use of antibiotics can result in bacterial antibiotic resistance, new strategies for disease prevention are needed. Roseobacter-clade bacteria from turbot larval rearing facilities can antagonize...... Vibrio anguillarum and reduce mortality in V. anguillarum-infected cod and turbot larvae. In this study, it was demonstrated that antagonistic Roseobacter-clade bacteria could be isolated from sea bass larval rearing units. In addition, it was shown that they not only antagonized V. anguillarum but also...

  6. Biological activity of neosergeolide and isobrucein B (and two semi-synthetic derivatives isolated from the Amazonian medicinal plant Picrolemma sprucei (Simaroubaceae

    Directory of Open Access Journals (Sweden)

    Ellen CC Silva

    2009-02-01

    Full Text Available In the present study, in vitro techniques were used to investigate a range of biological activities of known natural quassinoids isobrucein B (1 and neosergeolide (2, known semi-synthetic derivative 1,12-diacetylisobrucein B (3, and a new semi-synthetic derivative, 12-acetylneosergeolide (4. These compounds were evaluated for general toxicity toward the brine shrimp species Artemia franciscana, cytotoxicity toward human tumour cells, larvicidal activity toward the dengue fever mosquito vector Aedes aegypti, haemolytic activity in mouse erythrocytes and antimalarial activity against the human malaria parasite Plasmodium falciparum. Compounds 1 and 2 exhibited the greatest cytotoxicity against all the tumor cells tested (IC50 = 5-27 µg/L and against multidrug-resistant P. falciparum K1 strain (IC50 = 1.0-4.0 g/L and 3 was only cytotoxic toward the leukaemia HL-60 strain (IC50 = 11.8 µg/L. Quassinoids 1 and 2 (LC50 = 3.2-4.4 mg/L displayed greater lethality than derivative 4 (LC50 = 75.0 mg/L toward A. aegypti larvae, while derivative 3 was inactive. These results suggest a novel application for these natural quassinoids as larvicides. The toxicity toward A. franciscana could be correlated with the activity in several biological models, a finding that is in agreement with the literature. Importantly, none of the studied compounds exhibited in vitro haemolytic activity, suggesting specificity of the observed cytotoxic effects. This study reveals the biological potential of quassinoids 1 and 2 and to a lesser extent their semi-synthetic derivatives for their in vitro antimalarial and cytotoxic activities.

  7. Sprains and Strains

    Science.gov (United States)

    ... people at risk for strains. Gymnastics, tennis, rowing, golf, and other sports that require extensive gripping can ... Trials and You was designed to help people learn more about clinical trials, why they matter, and ...

  8. The strained state cosmology

    CERN Document Server

    Tartaglia, Angelo

    2015-01-01

    Starting from some relevant facts concerning the behaviour of the universe over large scale and time span, the analogy between the geometric approach of General Relativ- ity and the classical description of an elastic strained material continuum is discussed. Extending the elastic deformation approach to four dimensions it is shown that the accelerated expansion of the universe is recovered. The strain field of space-time repro- duces properties similar to the ones ascribed to the dark energy currently called in to explain the accelerated expansion. The strain field in the primordial universe behaves as radiation, but asymptotically it reproduces the cosmological constant. Subjecting the theory to a number of cosmological tests confirms the soundness of the approach and gives an optimal value for the one parameter of the model, i.e. the bulk modulus of the space-time continuum. Finally various aspects of the Strained State Cosmology (SSC) are discussed and contrasted with some non-linear massive gravity theor...

  9. An Ultrasonic Strain Gauge

    OpenAIRE

    Kersemans, Mathias; Allaer, Klaas; Degrieck, Joris; Van Den Abeele, Koen; Pyl, Lincy; Zastavnik, Filip; Sol, Hugo; Van Paegem, Wim

    2014-01-01

    A method is introduced for the measurements of strain exploiting the interaction between ultrasound waves and characteristics of the insonified specimen. First, the response of obliquely incident harmonic waves to a deterministic surface roughness is utilized. Analysis of backscattered amplitudes in Bragg diffraction geometry then yields a measure for the in-plane strain field by mapping any shift in angular dependency. Secondly, the analysis of the reflection characteristics of normal incide...

  10. The effects of mixture commercial live bakers’ yeast and probiotic bacillus on growth and feeding performance and survival rate of silver carp (Hypophthalmichthys molitrix larvae via bioencapsulated Artemia urmiana nauplii

    Directory of Open Access Journals (Sweden)

    Hossein Adineh

    2011-07-01

    Full Text Available Hypophthalmichthys molitrix (Valenciennes, 1844 larvae is an important species forfreshwater aquaculture. This study evaluated the effects of feeding a blend of probiotic bacilli bacteria(B. polymixa, B. licheniformis, B. circulans and baker´s yeast (Saccharomyces cerevisiae on growth and feeding parameters and survival rate of Silver carp larvae. Artemia urmiana (Gǘnther, 1899 nauplii is an important live food that was used as a vector to carry probiotic bacillus to digestive tract of silver carp larvae. The fish larvae were fed at a level of 10 percent body weight at 4 times a day for 30 days. Fish larvae in experimental treatments were fed A. urmiana nauplii that were enriched by blend of 50 percent of Bacillus spp. with concentrations of 1×105, 2×105, 3×105 and 4×105 CFU mL-1 and 50 percent of baker´s yeast with concentrations of 1×105, 2×105, 3×105 and 4×105 cellsmL-1 (T1, T2, T3, T4, respectively and were compared to fish larvae fed control diets of unbioencapsulated A. urmiananauplii. The experiment indicated that feeding and growth parameters in fish fed experimental treatments were significantly higher than fish fed control diets (P<0.05 but survival rate did not significantly differ. Overall, the best group was fed the highest level of yeast and probiotic.

  11. Muscle strain injuries.

    Science.gov (United States)

    Garrett, W E

    1996-01-01

    One of the most common injuries seen in the office of the practicing physician is the muscle strain. Until recently, little data were available on the basic science and clinical application of this basic science for the treatment and prevention of muscle strains. Studies in the last 10 years represent action taken on the direction of investigation into muscle strain injuries from the laboratory and clinical fronts. Findings from the laboratory indicate that certain muscles are susceptible to strain injury (muscles that cross multiple joints or have complex architecture). These muscles have a strain threshold for both passive and active injury. Strain injury is not the result of muscle contraction alone, rather, strains are the result of excessive stretch or stretch while the muscle is being activated. When the muscle tears, the damage is localized very near the muscle-tendon junction. After injury, the muscle is weaker and at risk for further injury. The force output of the muscle returns over the following days as the muscle undertakes a predictable progression toward tissue healing. Current imaging studies have been used clinically to document the site of injury to the muscle-tendon junction. The commonly injured muscles have been described and include the hamstring, the rectus femoris, gastrocnemius, and adductor longus muscles. Injuries inconsistent with involvement of a single muscle-tendon junction proved to be at tendinous origins rather than within the muscle belly. Important information has also been provided regarding injuries with poor prognosis, which are potentially repairable surgically, including injuries to the rectus femoris muscle, the hamstring origin, and the abdominal wall. Data important to the management of common muscle injuries have been published. The risks of reinjury have been documented. The early efficacy and potential for long-term risks of nonsteroidal antiinflammatory agents have been shown. New data can also be applied to the field

  12. Longitudinal misalignment based strain sensor

    OpenAIRE

    Andrews, Jeffrey Pratt

    1989-01-01

    A practical fiber optic strain sensor has been developed to measure strains in the range of 0.0 to 2.0 percent strain with a resolution ranging between 10 and 100 microstrain depending on sensor design choices. This intensity based sensor measures strain by monitoring strain induced longitudinal misalignment in a novel fiber interconnection. This interconnection is created by aligning fibers within a segment of hollow core fiber. Related splice loss mechanisms are investigated ...

  13. Monitoring Change in Great Salt Lake

    Science.gov (United States)

    Naftz, David; Angeroth, Cory; Freeman, Michael; Rowland, Ryan; Carling, Gregory

    2013-08-01

    Great Salt Lake is the largest hypersaline lake in the Western Hemisphere and the fourth largest terminal lake in the world (Figure 1). The open water and adjacent wetlands of the Great Salt Lake ecosystem support millions of migratory waterfowl and shorebirds from throughout the Western Hemisphere [Aldrich and Paul, 2002]. In addition, the area is of important economic value: Brine shrimp (Artemia franciscana) residing in Great Salt Lake support an aquaculture shrimp cyst industry with annual revenues as high as $60 million.

  14. Gut reaction by heartless shrimps: experimental evidence for the role of the gut in generating circulation before cardiac ontogeny

    OpenAIRE

    Spicer, John I

    2006-01-01

    Before the appearance of a functional heart in many invertebrate species, the assumption was that general body movements provide circulatory function. Consequently, I investigated the frequency of gut movements in the brine shrimp, Artemia franciscana, immediately post-hatch to the point when a functional heart appeared. Prior to cardiac ontogeny, movements of internal musculature and gut provided pre-cardiac circulatory currents with the rate of gut movements increasing when swimming limbs w...

  15. Asymptomatic bacteriuria Escherichia coli strains

    DEFF Research Database (Denmark)

    Hancock, Viktoria; Nielsen, E.M.; Klemm, Per

    2006-01-01

    to uropathogenic E. coli (UPEC) that cause symptomatic UTI, very little is known about the mechanisms by which these strains colonize the urinary tract. Here, we have investigated the growth characteristics in human urine as well as adhesin repertoire of nine ABU strains; the ability of ABU strains to compete...... against the UPEC strain CFT073 was also studied. The different ABU strains displayed a wide variety of the measured characteristics. Half of the ABU strains displayed functional type 1 fimbriae while only one expressed functional P fimbriae. A good correlation between the growth rate of a particular...

  16. Strains in General Relativity

    CERN Document Server

    Bini, Donato; Geralico, Andrea

    2014-01-01

    The definition of relative accelerations and strains among a set of comoving particles is studied in connection with the geometric properties of the frame adapted to a "fiducial observer." We find that a relativistically complete and correct definition of strains must take into account the transport law of the chosen spatial triad along the observer's congruence. We use special congruences of (accelerated) test particles in some familiar spacetimes to elucidate such a point. The celebrated idea of Szekeres' compass of inertia, arising when studying geodesic deviation among a set of free-falling particles, is here generalized to the case of accelerated particles. In doing so we have naturally contributed to the theory of relativistic gravity gradiometer. Moreover, our analysis was made in an observer-dependent form, a fact that would be very useful when thinking about general relativistic tests on space stations orbiting compact objects like black holes and also in other interesting gravitational situations.

  17. Strains in general relativity

    International Nuclear Information System (INIS)

    The definition of relative accelerations and strains among a set of comoving particles is studied in connection with the geometric properties of the frame adapted to a 'fiducial observer'. We find that a relativistically complete and correct definition of strains must take into account the transport law of the chosen spatial triad along the observer's congruence. We use special congruences of (accelerated) test particles in some familiar spacetimes to elucidate such a point. The celebrated idea of Szekeres' compass of inertia, arising when studying geodesic deviation among a set of free-falling particles, is here generalized to the case of accelerated particles. In doing so we have naturally contributed to the theory of relativistic gravity gradiometer. Moreover, our analysis was made in an observer-dependent form, a fact that would be very useful when thinking about general relativistic tests on space stations orbiting compact objects like black holes and also in other interesting gravitational situations

  18. Avaliação de extratos de macroalgas bênticas do litoral catarinense utilizando o teste de letalidade para Artemia salina Evaluation of macroalgae from Santa Catarina’s coast with the brine shrimp assay

    Directory of Open Access Journals (Sweden)

    Cintia Lhullier

    2006-06-01

    Full Text Available Foram coletadas amostras de algas marinhas de 19 espécies (sendo 4 pertencentes ao filo Chlorophyta, 5 ao filo Phaeophyta e 10 ao filo Rhodophyta em dois locais do litoral catarinense. Os extratos etanólicos foram submetidos ao teste de letalidade para larvas de Artemia salina com objetivo de realizar uma triagem das espécies. Dos 26 extratos testados, 25 apresentaram toxicidade significativa em pelo menos uma das 3 concentrações testadas. O grupo de algas vermelhas (Rhodophyta foi o que obteve maior porcentagem de extratos com resultados estatisticamente significativos pelo método do qui-quadrado e também menores valores de CL50, com destaque para Acanthophora spicifera, Hypnea musciformis e Pterocladiella capillacea. Observaram-se diferenças entre as espécies de um mesmo gênero (Codium decorticatum e Codium isthmocladium e também a influência de fatores ambientais (Hypnea musciformis na toxicidade dos extratos.Samples of 19 macroalgae species (4 Chlorophyta, 5 Phaeophyta and 10 Rhodophyta have been collected from two points of Santa Catarina's coast. The ethanolic extracts were avaluated with the brine shrimp assay in order to perform a screening for potential toxicity. A total of 25 extracts presented significant results in one or more of the tested concentrations. The phylum Rhodophyta presented more statistically significant results with the chi-square test, as well as lower values of LC50. The extracts of Acanthophora spicifera (from Canasvieiras and Ilha do Francês, Hypnea musciformis and Pterocladiella capillacea (both from Ilha do Francês presented LC50 below 50 mg/mL. Differences between the species of same genus (Codium decorticatum and Codium isthmocladium and the influence of environmental factors (Hypnea musciformis were observed.

  19. The Potential Roles of the G1LEA and G3LEA Proteins in Early Embryo Development and in Response to Low Temperature and High Salinity in Artemia sinica.

    Science.gov (United States)

    Zhao, Wei; Yao, Feng; Zhang, Mengchen; Jing, Ting; Zhang, Shuang; Hou, Lin; Zou, Xiangyang

    2016-01-01

    Late embryogenesis abundant proteins (LEA) are stress resistance-related proteins that play crucial roles in protecting against desiccation, cold and high salinity in a variety of animals and plants. However, the expression pattern, distribution and functions of LEA proteins in the post-diapause period of Artemia sinica, and under high salinity and low temperature stresses, remain unknown. In this study, the complete cDNA sequences of the group 1 LEA (As-g1lea) and group 3 LEA (As-g3lea) genes from A. sinica were cloned. The expression patterns and location of As-G1LEA and As-G1LEA were investigated. The protein abundances of As-G1LEA, As-G3LEA and Trehalase were analyzed during different developmental stages of the embryo and under low temperature and high salinity stresses in A. sinica. The full-length cDNA of As-g1lea was 960 bp, encoding a 182 amino acid protein, and As-g3lea was 2089 bp, encoding a 364 amino acid protein. As-g1lea and As-g3lea showed their highest expressions at 0 h of embryonic development and both showed higher relative expression in embryonic, rather than adult, development stages. The abundances of As-G1LEA, As-G3LEA and trehalose were upregulated under low temperature and downregulated under high salinity stress. These two genes did not show any tissue or organ specific expression. Our results suggested that these LEA proteins might play a pivotal role in stress tolerance in A. sinica. PMID:27603306

  20. MEMS Resonant Strain Sensor Integration

    OpenAIRE

    Myers, David Richard

    2010-01-01

    Despite commercial availability since the 1950's, silicon strain sensors have not experienced the same success as other microdevices, such as accelerometers, pressure sensors, and inkjet heads. Strain sensors measure mechanical deformation and could be used in many structural components, improving safety, controls, and manufacturing tolerances. This thesis examines major strain sensing techniques and highlights both advantages and disadvantages of each. MEMS resonant strain gauges are iden...

  1. Development of reversible strain gage

    International Nuclear Information System (INIS)

    A high-temperature strain gage which can be peeled after taking required apparent strain measurements in a furnace and can be attached reverse-side-up at the point of interest on a test structure was developed. Using the ''reversible'' strain gage with selected room-temperature curing type polyester adhesive, one can expect to measure thermal strain accurately, especially for on large structures, at the first test in temperature up to 250 deg C. The repeatability of apparent strains for about 100 reversible gages was within 50 microstrains of difference at 250 deg C (within 30 microstrains of difference for 80 % of the test gages). (author)

  2. [Echinococcus and strain concepts].

    Science.gov (United States)

    Utük, Armağan Erdem; Simsek, Sami

    2008-01-01

    Hydatid disease (echinococcosis) is one of the most important parasitic zoonoses and remains a public health and economic problem all over the world. Echinococcus granulosus includes a number of genetic variants and, up to date, analyses of mitochondrial DNA sequences have identified ten distinct genetic types (genotypes G1-10). This categorization follows closely the pattern of strain variation emerging based on biological characteristics. The extensive variation in E. granulosus may influence life-cycle patterns, host specificity, development rate, antigenicity, transmission dynamics, sensitivity to chemotherapeutic agents, and pathology. In this review, the recent genetic characterizations of Echinococcus genus have been summarized. PMID:18351549

  3. Reconstruction of axisymmetric strain distributions via neutron strain tomography

    International Nuclear Information System (INIS)

    Predicting the behaviour of structural components under a particular set of loading conditions requires knowledge of the residual elastic strain distribution throughout the bulk of these components. Characterising the 3D strain state at any particular point involves the measurement of six independent components which make up the second order strain tensor. Mapping the complete strain distribution throughout large volumes thus presents significant practical challenges. One possible solution to this problem is to reconstruct the 3D variation of strain components using tomographic techniques. The basic principle underpinning this idea is that the multi-component strain tensor can be reconstructed from a redundant set of lower order projection data. Here we demonstrate this fundamental concept for two samples: a shrink fit ‘ring-and-plug’ sample, and a spray-quenched circular cylinder, both possessing axially symmetric internal strain distribution. We present and contrast different approaches to the strain tomography problem. The methods described here can also be readily applied to high-energy X-ray diffraction measurements and represent an important step toward developing the tomographic reconstruction framework for strain tensor distributions of arbitrary complexity. The major benefit of neutron strain tomography is that the incident beam flux is utilised more fully, greatly reducing the data collection times. Using micro-channel plate (MCP) neutron detectors, a spatial resolution of the order of 0.1 mm can be achieved .

  4. Echocardiographic assessment of myocardial strain.

    Science.gov (United States)

    Gorcsan, John; Tanaka, Hidekazu

    2011-09-27

    Echocardiographic strain imaging, also known as deformation imaging, has been developed as a means to objectively quantify regional myocardial function. First introduced as post-processing of tissue Doppler imaging velocity converted to strain and strain rate, strain imaging has more recently also been derived from digital speckle tracking analysis. Strain imaging has been used to gain greater understanding into the pathophysiology of cardiac ischemia and infarction, primary diseases of the myocardium, and the effects of valvular disease on myocardial function, and to advance our understanding of diastolic function. Strain imaging has also been used to quantify abnormalities in the timing of mechanical activation for heart failure patients undergoing cardiac resynchronization pacing therapy. Further advances, such as 3-dimensional speckle tracking strain imaging, have emerged to provide even greater insight. Strain imaging has become established as a robust research tool and has great potential to play many roles in routine clinical practice to advance the care of the cardiovascular patient. This perspective reviews the physiology of myocardial strain, the technical features of strain imaging using tissue Doppler imaging and speckle tracking, their strengths and weaknesses, and the state-of-the-art present and potential future clinical applications.

  5. Estudo fitoquímico e bioensaio toxicológico frente a larvas de Artemia salina Leach. de três espécies medicinais do gênero Phyllanthus (Phyllanthaceae

    Directory of Open Access Journals (Sweden)

    J. E. NASCIMENTO

    2009-02-01

    Full Text Available

    Avaliou-se o perfil fitoquímico e a toxicidade de três espécies do gênero Phyllanthus (P. niruri, P. amarus e P. tenellus, coletadas em diferentes localidades do estado de Pernambuco, nordeste do Brasil. Os extratos brutos das três espécies foram submetidos a testes convencionais por cromatografia em camada delgada analítica para verificação das classes de metabólitos presentes, e testados frente a larvas de Artemia salina para obtenção das concentrações letais médias (CL50. Os testes fitoquímicos demonstraram a presença de flavonóides, saponinas, terpenos, naftoquinonas, alcalóides, antraquinonas, lignanas e taninos. As três espécies de Phyllanthus apresentaram variações na composição fitoquímica e na toxicidade frente a A. salina. Dependendo do local de coleta, os valores de CL50 variaram de 404,43 ± 49,64 µg/mL a 770,84 ± 51,78 µg/mL para P. niruri, 837,65 ± 61,45 µg/mL a 1075,89 ± 70,72 µg/mL para P. amarus e 534,60 ± 46,83 µg/mL a 1003,62 ± 65,15 µg/mL para P. tenellus. Palavras-chave: Phyllanthus niruri; Phyllanthus amarus,/i>; Phyllanthus tenellus; análise fitoquímica preliminar; bioensaio toxicológico; CL50

  6. Análise fitoquímica, potencial antioxidante e toxicidade do extrato bruto etanólico e das frações da espécie Senecio westermaniiDusén frente à Artemia salina

    Directory of Open Access Journals (Sweden)

    F.J.Z. MERINO

    2015-01-01

    Full Text Available RESUMO A espécie Senecio westermanii Dusén pertencente à família Asteraceae é planta endêmica e nativa do Brasil encontrada na região da Floresta Atlântica, nos estados do Paraná e São Paulo. O objetivo deste trabalho foi avaliar a composição fitoquímica do extrato bruto etanólico e frações das partes aéreas (folha e caule de S. westermanii utilizando-se a análise fitoquímica qualitativa e cromatografia líquida de alta eficiência com detector de arranjo de diodos (CLAE-DAD, avaliar in vitro a toxicidade preliminar utilizando Artemia salina e o potencial antioxidante. O estudo fitoquímico qualitativo revelou a presença de alcaloides, flavonoides, iridoides, esteroides/triterpenos, heterosídeos saponínicos e aminogrupos. Através da análise realizada por CLAE-DAD obteve-se o fingerprint característico de cada amostra. No ensaio frente à A. salina houve ausência de toxicidade das amostras, o resultado da DL50 para todas as amostras foi superior a 1000 μg/mL. Todas as amostras apresentaram atividade antioxidante pela redução do complexo fosfomolibdênio, com destaque para a fração clorofórmio que apresentou atividade antioxidante de 92,51% em relação ao padrão rutina. Com relação ao ensaio de redução do radical DPPH•, a fração acetato de etila apresentou IC50 de 26,98 μg/mL. Pelo ensaio do ácido tiobarbitúrico (TBARS a fração hexano apresentou o melhor índice antioxidante em relação ao padrão rutina. Os resultados obtidos demonstram evidências de que a espécie é fonte potencial de antioxidantes naturais, estimulando assim novos estudos que viabilizam sua utilização no tratamento de patologias associadas aos radicais livres. Além disso, a espécie não apresentou atividade tóxica preliminar, assegurando sua aplicabilidade.

  7. Evaluation of Strain Hardening Parameters

    Institute of Scientific and Technical Information of China (English)

    DING Zong-hai; Pavel Huml; YANG Wei

    2004-01-01

    The plane-strain compression test for three kinds of materials was carried out in a temperature range between room temperature and 400 ℃. The σ - ε curves and strain-hardening rate at different temperatures were simulated and a reasonable fit to the experimental data was obtained. A modified model created by data inference and computer simulation was developed to describe the strain hardening at a large deformation, and the predicted strain hardening are in a good agreement with that observed in a large range of stress. The influences of different parameters on strain hardening behaviour under large deformation were analysed. The temperature increase within the test temperatures for stainless steel 18/8 Ti results in dropping of flow stress and strain-hardening rate. For favourable γ-fibre texture to obtain high r, the cold rolling was applied at large reduction. In the experimental procedure, the X-ray diffraction test was carried out to compare the strain hardening and microstructure under large deformation for a bcc steel (low carbon steel SS-1142). The results indicate that the high strain-hardening rate possibly occurs when the primary slip plane {110} is parallel to the rolling plane and the strain-hardening rate decreases when lots of {110} plane rotate out from the orientation {110}∥RP.

  8. Hydrogen production from microbial strains

    Science.gov (United States)

    Harwood, Caroline S; Rey, Federico E

    2012-09-18

    The present invention is directed to a method of screening microbe strains capable of generating hydrogen. This method involves inoculating one or more microbes in a sample containing cell culture medium to form an inoculated culture medium. The inoculated culture medium is then incubated under hydrogen producing conditions. Once incubating causes the inoculated culture medium to produce hydrogen, microbes in the culture medium are identified as candidate microbe strains capable of generating hydrogen. Methods of producing hydrogen using one or more of the microbial strains identified as well as the hydrogen producing strains themselves are also disclosed.

  9. Tissue Velocity, Strain und Strain Rate bei Hunden mit Mitralklappenendokardiose

    OpenAIRE

    Javornik, Ana

    2007-01-01

    In der vorliegenden Arbeit „Tissue Velocity, Strain und Strain Rate bei Hunden mit Mitralklappenendokardiose“ wurden erstmals die Geschwindigkeits- und Verformungsparameter zur Evaluierung von Hunden mit Mitralklappenendokardiose angewendet. Diese erweisen sich als neue und viel versprechende Möglichkeiten zur Quantifizierung der regionalen Myokardfunktion. Die myokardialen Funktionsparameter finden in der Humanmedizin weit verbreitete Anwendung und auch in der Tiermedizin erlangen sie zunehm...

  10. Will the swine strain crowd out the seasonal influenza strain?

    CERN Document Server

    Schinazi, Rinaldo B

    2010-01-01

    We use spatial and non spatial models to argue that competition alone may explain why two influenza strains do not usually coexist. The more virulent strain is likely to crowd out the less virulent one. This can be seen as a consequence of the Exclusion Principle of Ecology. We exhibit, however, a spatial model for which coexistence is possible.

  11. Strain correction in interleaved strain-encoded (SENC) cardiac MR

    Science.gov (United States)

    Motaal, Abdallah G.; Osman, Nael F.

    2010-03-01

    The strain encoding (SENC) technique directly encodes regional strain of the heart into the acquired MR images and produces two images with two different tunings so that longitudinal strain, on the short-axis view, or circumferential strain on the long-axis view, are measured. Interleaving acquisition is used to shorten the acquisition time of the two tuned images by 50%, but it suffers from errors in the strain calculations due to inter-tunings motion of the heart. In this work, we propose a method to correct for the inter-tunings motion by estimating the motion-induced shift in the spatial frequency of the encoding pattern, which depends on the strain rate. Numerical data was generated to test the proposed method and real images of human subjects were used for validation. The proposed method corrected the measured strain values so they became nearly identical to the original ones. The results show an improvement in strain calculations so as to relax the imaging constraints on spatial and temporal resolutions and improve image quality.

  12. Detoxification and color removal of Congo red by a novel Dietzia sp. (DTS26) - a microcosm approach.

    Science.gov (United States)

    Satheesh Babu, S; Mohandass, C; Vijayaraj, A S; Dhale, Mohan A

    2015-04-01

    The present study deals with the decolorization and detoxification of Congo red (CR) by a novel marine bacterium Dietzia sp. (DTS26) isolated from Divar Island, Goa, India. The maximum decolorization of 94.5% (100 mg L(-1)) was observed under static condition within 30 h at pH 8 and temperature 32±2°C. Bacterially treated samples could enhance the light intensity by 38% and the primary production levels 5 times higher than the untreated. The strain was also able to reduce COD by 86.4% within 30 h at 100 mg L(-1) of CR dye. The degraded metabolites of CR dye were analyzed by FTIR, HPLC, GC-MS and the end product closely matches with 4-amino-3-naphthol-1-sulfonate which is comparatively less toxic than CR. Bioassay experiments conducted in treated samples for Artemia franciscana showed better survival rates (after 72 h) at higher concentration of CR (500 mg L(-1)). This work suggests the potential application of DTS26 in bioremediation of dye wastes and its safe disposal into coastal environment.

  13. Functional Role of Native and Invasive Filter-Feeders, and the Effect of Parasites: Learning from Hypersaline Ecosystems

    Science.gov (United States)

    Green, Andy J.

    2016-01-01

    Filter-feeding organisms are often keystone species with a major influence on the dynamics of aquatic ecosystems. Studies of filtering rates in such taxa are therefore vital in order to understand ecosystem functioning and the impact of natural and anthropogenic stressors such as parasites, climate warming and invasive species. Brine shrimps Artemia spp. are the dominant grazers in hypersaline systems and are a good example of such keystone taxa. Hypersaline ecosystems are relatively simplified environments compared with much more complex freshwater and marine ecosystems, making them suitable model systems to address these questions. The aim of this study was to compare feeding rates at different salinities and temperatures between clonal A. parthenogenetica (native to Eurasia and Africa) and the invasive American brine shrimp A. franciscana, which is excluding native Artemia from many localities. We considered how differences observed in laboratory experiments upscale at the ecosystem level across both spatial and temporal scales (as indicated by chlorophyll-a concentration and turbidity). In laboratory experiments, feeding rates increased at higher temperatures and salinities in both Artemia species and sexes, whilst A. franciscana consistently fed at higher rates. A field study of temporal dynamics revealed significantly higher concentrations of chlorophyll-a in sites occupied by A. parthenogenetica, supporting our experimental findings. Artemia parthenogenetica density and biomass were negatively correlated with chlorophyll-a concentration at the spatial scale. We also tested the effect of cestode parasites, which are highly prevalent in native Artemia but much rarer in the invasive species. The cestodes Flamingolepis liguloides and Anomotaenia tringae decreased feeding rates in native Artemia, whilst Confluaria podicipina had no significant effect. Total parasite prevalence was positively correlated with turbidity. Overall, parasites are likely to reduce

  14. Functional Role of Native and Invasive Filter-Feeders, and the Effect of Parasites: Learning from Hypersaline Ecosystems.

    Science.gov (United States)

    Sánchez, Marta I; Paredes, Irene; Lebouvier, Marion; Green, Andy J

    2016-01-01

    Filter-feeding organisms are often keystone species with a major influence on the dynamics of aquatic ecosystems. Studies of filtering rates in such taxa are therefore vital in order to understand ecosystem functioning and the impact of natural and anthropogenic stressors such as parasites, climate warming and invasive species. Brine shrimps Artemia spp. are the dominant grazers in hypersaline systems and are a good example of such keystone taxa. Hypersaline ecosystems are relatively simplified environments compared with much more complex freshwater and marine ecosystems, making them suitable model systems to address these questions. The aim of this study was to compare feeding rates at different salinities and temperatures between clonal A. parthenogenetica (native to Eurasia and Africa) and the invasive American brine shrimp A. franciscana, which is excluding native Artemia from many localities. We considered how differences observed in laboratory experiments upscale at the ecosystem level across both spatial and temporal scales (as indicated by chlorophyll-a concentration and turbidity). In laboratory experiments, feeding rates increased at higher temperatures and salinities in both Artemia species and sexes, whilst A. franciscana consistently fed at higher rates. A field study of temporal dynamics revealed significantly higher concentrations of chlorophyll-a in sites occupied by A. parthenogenetica, supporting our experimental findings. Artemia parthenogenetica density and biomass were negatively correlated with chlorophyll-a concentration at the spatial scale. We also tested the effect of cestode parasites, which are highly prevalent in native Artemia but much rarer in the invasive species. The cestodes Flamingolepis liguloides and Anomotaenia tringae decreased feeding rates in native Artemia, whilst Confluaria podicipina had no significant effect. Total parasite prevalence was positively correlated with turbidity. Overall, parasites are likely to reduce

  15. Biomechanical strain of goldsmiths.

    Science.gov (United States)

    Cândido, Paula Emanuela Fernandes; Teixeira, Juliana Vieira Schmidt; Moro, Antônio Renato Pereira; Gontijo, Leila Amaral

    2012-01-01

    The work of the goldsmiths consists in the manufacture of jewelry. The piece, be it an earring, bracelet or necklace, is hand-assembled. This task requires precision, skill, kindness and patience. In this work, we make use of tools such as cuticle clippers and rounded tip, beads or precious stones and also pieces of metal. This type of activity requires a biomechanical stress of hands and wrists. In order to quantify the biomechanical stress, we performed a case study to measure the movements performed by an assembly of pieces of jewelry. As method for research, filming was done during assembly of parts to a paste, using a Nikon digital camera, for 1 (one) hour. The film was edited by Kinovea software, and the task was divided into cycles, each cycle corresponds to a complete object. In one cycle, there are four two movements of supination and pronation movements of the forearm. The cycle lasts approximately sixteen seconds, totaling 1800 cycles in eight hours. Despite the effort required of the wrists, the activity shows no complaints from the employees, but this fact does not mischaracterizes the ability of employees to acquire repetitive strain injuries and work-related musculoskeletal disorders. PMID:22317096

  16. What Are Sprains and Strains?

    Science.gov (United States)

    ... and Strains Find a Clinical Trial Journal Articles Sprains and Strains PDF Version Size: 119 KB Audio Version Time: 07: ... Twist a knee. Where Do Sprains Usually Occur? Sprains happen most often in the ankle. Sometimes when people fall and land on their ...

  17. Adductor muscle strains in sport.

    Science.gov (United States)

    Nicholas, Stephen J; Tyler, Timothy F

    2002-01-01

    An in-season adductor muscle strain may be debilitating for the athlete. Furthermore, an adductor strain that is treated improperly could become chronic and career threatening. Any one of the six muscles of the adductor group could be involved. The degree of injury can range from a minor strain (Grade I), where minimal playing time is lost, to a severe strain (Grade III) in which there is complete loss of muscle function. Ice hockey and soccer players seem particularly susceptible to adductor muscle strains. In professional ice hockey players throughout the world, approximately 10% of all injuries are groin strains. These injuries, which have been linked to hip muscle weakness, previous injuries to that area, preseason practice sessions and level of experience, may be preventable if such risk factors can be addressed before each season. Hip-strengthening exercises were shown to be an effective method of reducing the incidence of adductor strains in one closely followed National Hockey League ice hockey team. Despite the identification of risk factors and strengthening intervention for ice hockey players, adductor strains continue to occur throughout sport. Clinicians feel an active training programme, along with completely restoring the strength of the adductor muscle group, is the key to successful rehabilitation. Surgical intervention is available if nonoperative treatment fails for 6 months or longer. Adductor release and tenotomy was reported to have limited success in athletes. PMID:11929360

  18. Strain measurements at railway wheels

    International Nuclear Information System (INIS)

    The development of the radial strain component in railway wheels was investigated by neutron diffraction. In the as manufactured state four railway wheels were investigated. In all four wheels no significant strains were found. After 18,400 km usage first strain gradients close to the outer surface of the wheels were detected. In axial middle ranges the changes in strain are weak. After an usage of 61,000 km the gradients becomes strong at the axial outer position between about +700 με close below the tread and -500 με in a depth of 12.5 mm below the tread. At axial middle positions also strain gradients are formed. The end of live state (510,000 km) differs only slightly from the state measured after a usage of 61,000 km

  19. Pin clad strains in Phenix

    International Nuclear Information System (INIS)

    The Phenix reactor has operated for 4 years in a satisfactory manner. The first 2 sub-assembly loadings contained pins clad in solution treated 316. The principal pin strains are: diametral strain (swelling and irradiation creep), ovality and spiral bending of the pin (interaction of wire and pin cluster and wrapper). A pin cluster irradiated to a dose of 80 dpa F reached a pin diameter strain of 5%. This strain is principally due to swelling (low fission gas pressure). The principal parameters governing the swelling are instantaneous dose, time and temperature for a given type of pin cladding. Other types of steel are or will be irradiated in Phenix. In particular, cold-worked titanium stabilised 316 steel should contribute towards a reduction in the pin clad strains and increase the target burn-up in this reactor. (author)

  20. Chitin stimulates production of the antibiotic andrimid in a Vibrio corallilyticus strain

    DEFF Research Database (Denmark)

    Wietz, Matthias; Månsson, Maria; Gram, Lone

    2011-01-01

    per cell was twofold higher. In cultures with Artemia as live chitin model system, S2052 reached up to 108 cells ml-1, produced andrimid and showed attachment to the exoskeleton and chitinous exuviae. The metabolic focus on andrimid production with chitin indicates that the antibiotic could serve...

  1. Genetic diversity of Rhodopirellula strains.

    Science.gov (United States)

    Frank, Carsten S; Klockow, Christine; Richter, Michael; Glöckner, Frank Oliver; Harder, Jens

    2013-10-01

    Rhodopirellula baltica SH1(T) is a marine planctomycete with 7,325 genes in its genome. Ten strains of the genus Rhodopirellula were studied in whole genome microarray experiments to assess the extent of their genetic relatedness to R. baltica SH1(T). DNA of strains which were previously affiliated with the species R. baltica (OTU A) hybridized with 3,645-5,728 genes of the type strain on the microarray. Strains SH398 and 6C (OTU B), representing a closely related species with an average nucleotide identity of 88 %, showed less hybridization signals: 1,816 and 3,302 genes gave a hybridization signal, respectively. Comparative genomics of eight permanent draft genomes revealed the presence of over 4,000 proteins common in R. baltica SH1(T) and strains of OTU A or B. The genus Rhodopirellula is characterized by large genomes, with over 7,000 genes per genome and a core genome of around 3000 genes. Individual Rhodopirellula strains have a large portion of strain-specific genes. PMID:23975513

  2. Magnetostriction strain measurement: heterodyne laser interferometry versus strain gauge technique

    OpenAIRE

    Gorji Ghalamestani, Setareh; Vandevelde, Lieven; J.J. Dirckx, Joris; Melkebeek, Jan

    2013-01-01

    Deformation of the ferromagnetic material, known as magnetostriction, causes vibrations and noise of electrical machines and transformer cores. A setup by using heterodyne laser interferometers has been built to measure the magnetostriction strains as a function of the applied magnetic field. The measurement results on a sample of nonoriented electrical steel are presented in this work. These results are compared with those obtained by using a strain gauge setup. The laser measurements are l...

  3. Low TCR nanocomposite strain gages

    Science.gov (United States)

    Gregory, Otto J. (Inventor); Chen, Ximing (Inventor)

    2012-01-01

    A high temperature thin film strain gage sensor capable of functioning at temperatures above 1400.degree. C. The sensor contains a substrate, a nanocomposite film comprised of an indium tin oxide alloy, zinc oxide doped with alumina or other oxide semiconductor and a refractory metal selected from the group consisting of Pt, Pd, Rh, Ni, W, Ir, NiCrAlY and NiCoCrAlY deposited onto the substrate to form an active strain element. The strain element being responsive to an applied force.

  4. Síntese, toxicidade frente a Artemia salina Leach e avaliação da atividade antimicrobiana de 1,2,4-oxadiazóis-3,5-difenilclorados - DOI: 10.4025/actascitechnol.v27i2.1452

    Directory of Open Access Journals (Sweden)

    Silvio Luiz Machado

    2005-03-01

    Full Text Available Os oxadiazóis 3,5-bis-(fenil-1,2,4-oxadiazol (3a e 3-(4-clorofenil-5-fenil-1,2,4-oxadiazol (3b, já descritos na literatura, e, os 1,2,4-oxadiazóis-3,5-fenilclorados inéditos 3c-e, foram sintetizados pela reação de bezamidoximas com um cloreto de ácido apropriado, seguido da ciclização do intermediário O-acilíco resultante. Os compostos obtidos foram caracterizados com base nas análises dos dados espectroscópicos de IV, EM e RMN (uni- e bidimensionais. Os compostos 3a-e foram submetidos a bioensaios para avaliação de atividade antimicrobiana e, de toxicidade frente ao microcrustáceo Artemia salina Leach

  5. Hypervirulent strains of Clostridium difficile

    OpenAIRE

    Cookson, Barry

    2007-01-01

    North America has seen increasing numbers of hospitalised patients and others in nursing homes and the community, with more severe Clostridium difficile associated diarrhoea. This is also described in Northern Europe and surveillance systems are being developed or improved to monitor the situation. One strain (ribotype O27) is described in detail and, like other emerging strains, is demonstrating increasing antimicrobial resistance, notably to quinolone antibiotics. However, its association w...

  6. Canning Tests on Mushroom Strain

    OpenAIRE

    Gormley, T. R. (Thomas Ronan); MacCanna, C.

    1980-01-01

    Canning tests were carried out on 5 mushroom strains from 2 flushes of 4 separate crops. Particular attention was given to the ratio of whole closed canned mushrooms to that of whole closed canned mushrooms plus canned stems and pieces - i.e. total yield. Factors considered in the tests included grading prior to processing, blanching and retort losses, shrinkage in size and mushroom whiteness. Cream and off-white strains had the highest level of open and misshapen mushrooms prior to processin...

  7. Covalent functionalization of strained graphene

    OpenAIRE

    Boukhvalov, Danil W.; Son, Young-Woo

    2012-01-01

    Enhancement of the chemical activity of graphene is evidenced by first-principles modelling of chemisorption of the hydrogen, fluorine, oxygen and hydroxyl groups on strained graphene. For the case of negative strain or compression, chemisorption of the single hydrogen, fluorine or hydroxyl group is energetically more favourable than those of their pairs on different sublattices. This behaviour stabilizes the magnetism caused by the chemisorption being against its destruction by the pair form...

  8. Roll bonding of strained aluminium

    DEFF Research Database (Denmark)

    Staun, Jakob M.

    2003-01-01

    This report investigates roll bonding of pre-strained (å ~ 4) aluminium sheets to produce high strain material from high purity aluminium (99.996%) and commercial pure aluminium (99.6%). The degree of bonding is investigated by optical microscopy and ultrasonic scanning. Under the right circumsta......This report investigates roll bonding of pre-strained (å ~ 4) aluminium sheets to produce high strain material from high purity aluminium (99.996%) and commercial pure aluminium (99.6%). The degree of bonding is investigated by optical microscopy and ultrasonic scanning. Under the right...... circumstances both materials show good bonding, but the high purity material is excluded because of recrystallisation and the resulting loss of mechanical properties. The effect of cross stacking and roll bonding pre-strained sheets of the commercial purity material is investigated and some dependence...... of the cross rolled volume fraction is found. To further asses this effect, and the anisotropy, it is necessary to acquire knowledge about both texture and microstructure, e.g. by TEM. Roll bonding of pre-strained aluminium is found to be a possible alternative to ARB in the quest for ultra-fine grained...

  9. Green synthesis of Silver nanoparticles through Calotropis gigantea leaf extracts and evaluation of antibacterial activity against Vibrio alginolyticus

    Directory of Open Access Journals (Sweden)

    Vaseeharan Baskaralingam

    2012-01-01

    Full Text Available Green synthesized silver nanoparticles by Calotropis gigantea leaf extract were used to study the inhibitory activity against pathogenic Vibrio alginolyticus, isolated from wild Artemia franciscana cysts. Silver nanoparticle synthesis was observed using UV-visible spectroscopy and the morphological characteristics were analyzed by atomic force microscope (AFM. In the present study, increasing concentrations of silver nanoparticles synthesized on LB agar plates effectively reduced the number of colonies of V. alginolyticus. A decrease in colonies (CFUs was observed at 5 mg/mL of silver nanoparticle concentration and the complete inhibition of V. alginolyticus was observed at 20 mg/mL of silver nanoparticle concentration on LB agar plates. In vivo controlling efficiency of silver nanoparticles was tested in an A. franciscana hatching system. Effective control of V. alginolyticus in brine shrimp A. franciscana hatching units was achieved by experimental infection and treatment with silver nanoparticles. Experimental infection studies showed that V. alginolyticus infected Artemia nauplii treated with silver nanoparticles (10 mg/mL had greater survival (>40% than silver nanoparticles not treated with nauplii. Based on the findings of this study, it is recommended that low concentrations of green synthesized silver nanoparticles should be further investigated for other potential experimental models to control potential medical pathogens.

  10. Genome Sequence of Pseudomonas chlororaphis Strain 189

    Science.gov (United States)

    Town, Jennifer; Audy, Patrice; Boyetchko, Susan M.

    2016-01-01

    Pseudomonas chlororaphis strain 189 is a potent inhibitor of the growth of the potato pathogen Phytophthora infestans. We determined the complete, finished sequence of the 6.8-Mbp genome of this strain, consisting of a single contiguous molecule. Strain 189 is closely related to previously sequenced strains of P. chlororaphis. PMID:27340063

  11. Strain Growth in Containment Vessels

    Institute of Scientific and Technical Information of China (English)

    DONG Q; LI Q M; ZHENG J Y

    2006-01-01

    Strain growth is a phenomenon observed in containment vessels subjected to internal blast loading.The elastic response of the vessel may become larger in a later stage compared to its response during the initial stage.The dynamic responses of infinitely long cylindrical containment vessels subjected to uniformly-distributed internal blast loading are studied using LS-DYNA.The development of bending modes and the interaction between the breathing mode and bending modes are observed.The methodology developed for dynamic elastic buckling analysis is employed to study the strain growth phenomenon in explosion containment vessels.It is shown that the dynamic instable vibration of a containment vessel is the basic mechanism of strain growth.

  12. Thermoelectric properties of strained silicon

    Energy Technology Data Exchange (ETDEWEB)

    Hinsche, Nicki F.; Zahn, Peter [Martin-Luther-Universitaet, Institut fuer Physik, Von-Seckendorff-Platz 1, 06120 Halle/S. (Germany); Mertig, Ingrid [Martin-Luther-Universitaet, Institut fuer Physik, Von-Seckendorff-Platz 1, 06120 Halle/S. (Germany); Max-Planck-Institut fuer Mikrostrukturphysik, Weinberg 2, D-06120 Halle (Germany)

    2011-07-01

    Starting from bulk silicon, we study the change in thermoelectric properties due to symmetry breaking in rolled-up and layered Si which might lead to nanostructured thermoelectrics. Valley splitting in strained Si caused by tetragonal distortion was studied recently with respect to the enhancement of electron mobility. Our results show that the tetragonal distortion has a strong influence on the electronic transport properties. The electronic structure is calculated self consistently within the framework of density functional theory. The transport properties are studied in the diffusive limit applying the Boltzmann theory in relaxation time approximation. In detail, the anisotropy of the electrical conductivity, the thermopower and the resulting powerfactor in the in-plane and off-plane directions are studied in dependence on strain, doping level and temperature. It is shown, that the powerfactor at a given temperature can be enhanced slightly by strain for p-doping, while no enhancement is obtained for n-doping.

  13. Spin transport in graphene superlattice under strain

    Science.gov (United States)

    Sattari, Farhad

    2016-09-01

    In this paper, the spin-dependent transport and the spin polarization properties for graphene superlattice with Rashba spin-orbit interaction (RSOI) in the presence of zigzag and armchair direction strain are studied. It is found that for the zigzag direction strain the angular range of the spin-inversion can be efficiently controlled by the strain strength. In addition, the efficiency of spin-inversion and spin-dependent conductivity decreases by increasing the strain strength. When the armchair direction strain is applied to a monolayer graphene superlattice the spin polarization can be observed and increases by increasing the strain strength, whereas for the zigzag direction strain it is zero.

  14. Myocardial Strain and Strain Rate Imaging: Comparison between Doppler Derived Strain Imaging and Speckle Tracking Echocardiography

    Directory of Open Access Journals (Sweden)

    Anita Sadeghpour

    2013-05-01

    Full Text Available Regional myocardial function has been traditionally assessed by visual estimation (1. Echocardiographic strain imaging which is known as deformation imaging, has been emerged as a quantitative technique to accurately estimate regional myocardial function and contractility. Currently, strain imaging has been regarded as a research tool in the most echocardiography laboratories. However, in recent years, strain imaging has gain momentum in daily clinical practice (2. The following two techniques have dominated the research arena of echocardiography: (1 Doppler based tissue velocity measurements, frequently referred to tissue Doppler or myocardial Doppler, and (2 speckle tracking on the basis of displacement measurements (3. Over the past two decades, Tissue Doppler Imaging (TDI and Doppler –derived strain (S and strain rate (SR imaging were introduced to quantify regional myocardial function. However, Doppler–derived strain variables faced criticisms, with regard to the angle dependency, noise interference, and substantial intraobserver and interobserver variability. The angle dependency is the major weakness of Doppler based methodology; however, it has the advantage of online measurements of velocities and time intervals with excellent temporal resolution, which is essential for the assessment of ischemia (4. Speckle-tracking echocardiography (STE or Non Doppler 2D strain echocardiography is a relatively new, largely angle-independent technique that analyzes motion by tracking natural acoustic reflections and interference patterns within an ultrasonic window. The image-processing algorithm tracks elements with approximately 20 to 40 pixels containing stable patterns and are described as ‘‘speckles’’ or ‘‘fingerprints’’. The speckles seen in grayscale B-mode (2D images are tracked consecutively frame to frame (5, 6. Assessment of 2D strain by STE is a semiautomatic method that requires definition of the myocardium

  15. Photoacoustic spectroscopy of Entamoeba histolytica strains

    Science.gov (United States)

    Acosta-Avalos, D.; Alvarado-Gil, J. J.; Silva, E. F.; Orozco, E.; de Menezes, L. F.; Vargas, H.

    2005-06-01

    Pathogenic and non-pathogenic strains of E. histolytica are studied using photoacoustic spectroscopy. It is shown that the pathogenic strain presents a spectrum similar to that of iron sulfur proteins. The non-pathogenic strain does not show any relevant absorption at the studied wavelength range. The differences observed between the optical absorption spectra of both strains opens the possibility of using photoacoustic spectroscopy as a reliable and simple technique to identify different types of E. histolytica strains.

  16. [Selected properties of Bacteroides fragilis enterotoxigenic strains].

    Science.gov (United States)

    Rokosz, A; Meisel-Mikołajczyk, F

    1995-01-01

    Seven B. fragilis strains were examined. One strain was reference, non-enterotoxigenic, representing serotype E2 according to Beerens et al. (1971). Six strains produced enterotoxin (ETBF). Four of them were isolated from human feces and two of them from swine feces. All strains were investigated morphologically, biochemically (ATB Expression, France) and by means of direct immunofluorescence (Bacteroides--IF test, Poland). Their resistance to chemotherapeutics was tested (ATB Expression, France). The MIC values of clindamycin and metronidazole were determined using E test strips (AB Biodisk, Sweden). Each strain formed capsules. The percentage of encapsulated cells was high (80-100%). Some strains produced thick capsules. Biochemical patterns were similar and typical for B. fragilis rods. One enterotoxigenic strain produced gelatinase and three ETBF strains fermented trehalose. All strains reacted in direct immunofluorescence exclusively with conjugate against serotype E of BFG. Thus, each strain showed antigenic pattern E. Drug susceptibility of all strains was similar. One enterotoxigenic strain was resistant to clindamycin. All strains were susceptible to metronidazole. These studies indicate that on the basis of morphological, biochemical and serological features (IF), enterotoxigenic B. fragilis strains cannot be distinguished from the nonenterotoxigenic one. Also, the correlation between toxigenicity and drug sensitivity of the examined strains is not observed.

  17. Laboratory review of reference strains of Corynebacterium diphtheriae indicates mistyped intermedius strains.

    OpenAIRE

    Coyle, M B; Nowowiejski, D J; Russell, J Q; Groman, N B

    1993-01-01

    All biotyped strains of Corynebacterium diphtheriae from the American Type Culture Collection (ATCC) were compared for morphology and biochemical reactions. Biotypes of all gravis strains and most mitis strains were confirmed, but intermedius strains were found to be misclassified. New lipid-dependent intermedius strains have been deposited with the ATCC.

  18. Trials with a Strain Gauge.

    Science.gov (United States)

    Auty, Geoff

    1996-01-01

    Describes an attempt to match the goals of the practical demonstration of the use of a strain gauge and the technical applications of science and responding to student questions in early trials, while keeping within the level of electronics in advanced physics. (Author/JRH)

  19. Job strain and alcohol intake

    DEFF Research Database (Denmark)

    Heikkilä, Katriina; Nyberg, Solja T; Fransson, Eleonor I;

    2012-01-01

    The relationship between work-related stress and alcohol intake is uncertain. In order to add to the thus far inconsistent evidence from relatively small studies, we conducted individual-participant meta-analyses of the association between work-related stress (operationalised as self-reported job...... strain) and alcohol intake....

  20. A NEW STRAIN OF TRANSMISSIBLE LEUCEMIA IN FOWLS (STRAIN H).

    Science.gov (United States)

    Ellermann, V

    1921-03-31

    1. A new strain of fowl leucosis has been transmitted through twelve generations of fowls. 2. An increase in virulence was observed during its passage. This was shown in a shortening of the interval between inoculation and death. The increase in virulence does not affect the number of successful inoculations, which remains approximately constant in from 20 to 40 per cent of the birds employed. 3. As with former strains, the disease manifests itself in various forms; i.e., myeloid and intravascular lymphoid types. A single lymphatic case was observed. 4. In several intravascular cases a diminution in the hemolytic power of the serum was established. This phenomenon was absent in a number of myeloid cases. 5. Active immunization cannot be produced by means of the subcutaneous injection of virulent material. 6. The finding of previous experiments that the virus is filterable has been confirmed. 7. The inoculation of human leucemic material into fowls gave negative results.

  1. Engineering piezoresistivity using biaxially strained silicon

    DEFF Research Database (Denmark)

    Pedersen, Jesper Goor; Richter, Jacob; Brandbyge, Mads;

    2008-01-01

    We calculate the shear piezocoefficient of p-type silicon with grown-in biaxial strain using a 66 k·p method. We find a significant increase in the value of the shear piezocoefficient for compressive grown-in biaxial strain, while tensile strain decreases the piezocoefficient. The dependence...... of the piezocoefficient on temperature and dopant density is altered qualitatively for strained silicon. In particular, we find that a vanishing temperature coefficient may result for silicon with grown-in biaxial tensile strain. These results suggest that strained silicon may be used to engineer the iezoresistivity...

  2. Plane strain test for metal sheet characterization

    OpenAIRE

    Flores, Paulo; Bonnet, Félix; Habraken, Anne

    2007-01-01

    This article shows the influence of a plane strain test specimen geometry on the measurable strain field and the influence of free edge effects over the stress computation. The experimental strain field distribution is measured over the whole deformable zone of a plane strain test specimen by an optical strain gauge. The chosen material is the DC06 IF steel of 0.8 mm thickness. The stress field is computed for several geometries at different strain levels by a Finite Element (FE) commer...

  3. Alimento vivo como alternativa en la dieta de larvas y juveniles de Pterophyllum scalare (Lichtenstein, 1823

    Directory of Open Access Journals (Sweden)

    J. Luna-Figueroa

    2010-01-01

    Full Text Available La nutrición en los estadios iniciales de los peces constituye uno de los principales problemas de cultivo, debido a que es la etapa en la que se presenta la mayor mortalidad. En el presente estudio se evaluó, como alternativa en la alimentación de larvas y juveniles de Pterophyllum scalare, el efecto de tres alimentos vivos (Moina wierzejski, Artemia franciscana y Panagrellus redivivus y un alimento comercial (Aquarian Tropical Flakes sobre la tasa específica de crecimiento (TEC y la sobrevivencia. La TEC de larvas resultó más alta con nauplios de A. franciscana (17.57 ± 0.39a% peso corporal ganado mg/ día, seguida de M. wierzejski (16.63 ± 0.41b, P. redivivus (14.25 ± 0.42c y del alimento comercial (13.20 ± 0.42d (P<0.05. En los juveniles, la TEC fue mayor con M. wierzejski (6.28 ± 0.21a% peso corporal ganado mg/día, seguida de A. franciscana (6.04 ± 0.23b, P. redivivus (4.86 ± 0.23c y del alimento comercial (4.39 ± 0.23d (P<0.05. La sobrevivencia de las larvas fue 80.00 ± 10.00a% con A. franciscana y M. wierzejski, mayor 25 y 40.62% con respecto a P. redivivus (60.00 ± 10.00b% y al alimento comercial (45.00 ± 10.00b% (P<0.05. En los juveniles, la sobrevivencia del 100% no difirió con ningún alimento. Finalmente, los nauplios de Artemia en la etapa larval y la Moina en juveniles estimularon favorablemente la TEC y la sobrevivencia de P. scalare.

  4. Monoclonal antibodies to Toxoplasma gondii strain 119 identify recently isolated Danish strains as one group

    DEFF Research Database (Denmark)

    Jensen, L.; Petersen, E.; Henriksen, S.A.;

    1998-01-01

    Four mAb raised against the Danish Toxoplasma gondii strain 119, were selected by screening hybridoma supernatants by indirect immunofluorescence against tachyzoites of the RH strain in order to obtain strain restricted markers. Strain restriction extended beyond discrimination of the 119 and RH...... strains, as demonstrated on a further six T. gondii reference strains [BK and GT1 (group A), NTE and 561 (group B), and NED and C56 (group C)]. The bradyzoite-specific mAb, 4.3, reacted to the GT1, NTE and 561 strains, but not to the BK, NED or C56 strains. The tachyzoite-specific mAb, 4.25, reacted....... gondii strain collection representative for a small geographic area (Denmark) was established within a short time span from a variety of animal species. Using the mAb as typing reagents to this Danish strain collection, all 36 animal and two human strains were identified as having the same reaction...

  5. Strain Monitoring of Flexible Structures

    Science.gov (United States)

    Litteken, Douglas A.

    2017-01-01

    , such as tensile testing, fatigue testing, and shear testing, but common measurement techniques cannot be used on fabric. Measuring strain in a material and during a test is a critical parameter for an engineer to monitor the structure during the test and correlate to an analytical model. The ability to measure strain in fabric structures is a challenge for NASA. Foil strain gauges, for example, are commonplace on metallic structures testing, but are extremely difficult to interface with a fabric substrate. New strain measuring techniques need to be developed for use with fabric structures. This paper investigates options for measuring strain in fabric structures for both ground testing and in-space structural health monitoring. It evaluates current commercially available options and outlines development work underway to build custom measurement solutions for NASA's fabric structures.

  6. EFFECTIVE STRESS AND STRAIN IN FINITE DEFORMATION

    Institute of Scientific and Technical Information of China (English)

    周喆; 秦伶俐; 黄文彬; 王红卫

    2004-01-01

    Whether the concept of effective stress and strain in elastic-plastic theory is still valid under the condition of finite deformation was mainly discussed. The uni-axial compression experiments in plane stress and plane strain states were chosen for study. In the two kinds of stress states, the stress- strain curve described by logarithm strain and rotated Kirchhoff stress matches the experiments data better than the curves defined by other stressstrain description.

  7. Temperature-Compensating Inactive Strain Gauge

    Science.gov (United States)

    Moore, Thomas C., Sr.

    1993-01-01

    Thermal contribution to output of active gauge canceled. High-temperature strain gauges include both active gauge wires sensing strains and inactive gauge wires providing compensation for thermal contributions to gauge readings. Inactive-gauge approach to temperature compensation applicable to commercially available resistance-type strain gauges operating at temperatures up to 700 degrees F and to developmental strain gauges operating at temperatures up to 2,000 degrees F.

  8. Piezoelectric field in strained GaAs.

    Energy Technology Data Exchange (ETDEWEB)

    Chow, Weng Wah; Wieczorek, Sebastian Maciej

    2005-11-01

    This report describes an investigation of the piezoelectric field in strained bulk GaAs. The bound charge distribution is calculated and suitable electrode configurations are proposed for (1) uniaxial and (2) biaxial strain. The screening of the piezoelectric field is studied for different impurity concentrations and sample lengths. Electric current due to the piezoelectric field is calculated for the cases of (1) fixed strain and (2) strain varying in time at a constant rate.

  9. Haemophilus ducreyi Cutaneous Ulcer Strains Are Nearly Identical to Class I Genital Ulcer Strains.

    Directory of Open Access Journals (Sweden)

    Dharanesh Gangaiah

    Full Text Available Although cutaneous ulcers (CU in the tropics is frequently attributed to Treponema pallidum subspecies pertenue, the causative agent of yaws, Haemophilus ducreyi has emerged as a major cause of CU in yaws-endemic regions of the South Pacific islands and Africa. H. ducreyi is generally susceptible to macrolides, but CU strains persist after mass drug administration of azithromycin for yaws or trachoma. H. ducreyi also causes genital ulcers (GU and was thought to be exclusively transmitted by microabrasions that occur during sex. In human volunteers, the GU strain 35000HP does not infect intact skin; wounds are required to initiate infection. These data led to several questions: Are CU strains a new variant of H. ducreyi or did they evolve from GU strains? Do CU strains contain additional genes that could allow them to infect intact skin? Are CU strains susceptible to azithromycin?To address these questions, we performed whole-genome sequencing and antibiotic susceptibility testing of 5 CU strains obtained from Samoa and Vanuatu and 9 archived class I and class II GU strains. Except for single nucleotide polymorphisms, the CU strains were genetically almost identical to the class I strain 35000HP and had no additional genetic content. Phylogenetic analysis showed that class I and class II strains formed two separate clusters and CU strains evolved from class I strains. Class I strains diverged from class II strains ~1.95 million years ago (mya and CU strains diverged from the class I strain 35000HP ~0.18 mya. CU and GU strains evolved under similar selection pressures. Like 35000HP, the CU strains were highly susceptible to antibiotics, including azithromycin.These data suggest that CU strains are derivatives of class I strains that were not recognized until recently. These findings require confirmation by analysis of CU strains from other regions.

  10. Spontaneous abortion and physical strain around implantation

    DEFF Research Database (Denmark)

    Hjøllund, Niels Henrik Ingvar; Jensen, T.K.; Bonde, J.P.;

    2000-01-01

    pregnancy the women recorded physical strain prospectively in a structured diary. Physical strain around the time of implantation was associated with later spontaneous abortion. The adjusted risk ratio for women who reported physical strain higher than average at day 6 to 9 after the estimated date...

  11. Lewis Strain Gauge Laboratory: Status and plans

    International Nuclear Information System (INIS)

    An in-house lab was established for developing, testing, and evaluating high-temperature strain gauges and to aid in in-house applications of high-temperature strain instrumentation. The lab is automated to provide computer control of oven temperatures, imposed strain, and data sampling

  12. On lower order strain gradient plasticity theories

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Hutchinson, J. W.

    2003-01-01

    By way of numerical examples, this paper explores the nature of solutions to a class of strain gradient plasticity theories that employ conventional stresses, equilibrium equations and boundary conditions. Strain gradients come into play in these modified conventional theories only to alter...... the tangent moduli governing increments of stress and strain. It is shown that the modification is far from benign from a mathematical standpoint, changing the qualitative character of solutions and leading to a new type of localization that is at odds with what is expected from a strain gradient theory....... The findings raise questions about the physical acceptability of this class of strain gradient theories....

  13. Transient temperature response of strain gages

    International Nuclear Information System (INIS)

    When an electrical resistance strain gage bonded to a material is subjected to a temperature change, the resistance of the strain gage changes even though the material is free of stress. This temperature-induced resistance change is generally expressed in strain units and is commonly called apparent strain or thermal output. The thermal expansion coefficients and the temperature coefficient of resistance are temperature-dependent quantities and not necessarily linearly related to temperature. For transient temperature conditions, the two temperatures are different. The magnitude and effect of this temperature difference on apparent strain is studied

  14. Strain Engineering of Transition Metal Dichalcogenides

    Science.gov (United States)

    Dadgar, Ali; Pasupathy, Abhay; Herman, Irving; Wang, Dennis; Kang, Kyungnam; Yang, Eui-Hyeok

    The application of strain to materials can cause changes to bandwidth, effective masses, degeneracies and even structural phases. In the case of the transition metal dichalcogenide (TMD) semiconductors, small strain (around 1 percent) is expected to change band gaps and mobilities, while larger strains are expected to cause phase changes from the triangular 2H phase to orthorhombic 1T' phases. We will describe experimental techniques to apply small and large (around 10 percent) strains to one or few layer samples of the TMD semiconductors, and describe the effect of the strain using optical (Raman, photoluminescence) and cryogenic transport techniques.

  15. Spontaneous abortion and physical strain around implantation

    DEFF Research Database (Denmark)

    Hjollund, N H; Jensen, Tina Kold; Bonde, Jens Peter;

    2000-01-01

    Existing studies of physical strain and spontaneous abortion are mainly retrospective or based only on pregnancies that have survived the first trimester. Furthermore, almost all studies have relied on averaged measures of physical strain, which tend to blur an effect if peak values during short...... pregnancy the women recorded physical strain prospectively in a structured diary. Physical strain around the time of implantation was associated with later spontaneous abortion. The adjusted risk ratio for women who reported physical strain higher than average at day 6 to 9 after the estimated date...

  16. Stress-strain properties of railway steel at strain rates of upto 105 per second

    International Nuclear Information System (INIS)

    This paper presents the stress-strain characteristics of railway steel at strain rates of up to 105/s at room temperature determined by a new technique. In determining the results, account has been taken of the strain-rate variation, the total strain and the strain rate history. The effect of friction, material inertia and temperature rise is also assessed and an empirical constitutive equation describing the strain-rate and strain sensitive flow stress for this type of steel is proposed. (orig.)

  17. Comparison between strain values of plates measured by ESPI technique and strain gauge method

    International Nuclear Information System (INIS)

    Comparison between strain values of plates measured by Electronic Speckle Pattern Interferometry(ESPI) method and strain gauge method is discussed. Unlike traditional method, such ax strain gauge and moire method, ESPI method requires no special surface preparations or attachments and can be measured in-plane displacement with non-contacting in real-time. In this study, specimens are loaded in parallel using tensile testing machine. In front of a specimen three strain gauges are bonded with 5 mm gap from edge of a specimen strain values are measured at each strain gauge position and compared. The results by ESPI method agree well with the result by strain gauge method.

  18. Computational strain gradient crystal plasticity

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Kysar, Jeffrey W.

    2014-01-01

    of plane crystal plasticity are studied: pure shear of a single crystal between rigid platens as well as plastic deformation around cylindrical voids in hexagonal close packed and face centered cubic crystals. Effective in-plane constitutive slip parameters for plane strain deformation of specifically...... oriented face centered cubic crystals are developed in terms of the crystallographic slip parameters. The effect on geometrically necessary dislocation structures introduced by plastic deformation is investigated as a function of the ratio of void radius to plasticity length scale....

  19. Strain gauges as intrusion detection sensors

    International Nuclear Information System (INIS)

    Strain gauges have been studied for use as intrusion detection sensors in several applications being investigated at Sandia National Laboratories. Strain gauges are attached to a metal structure to monitor the quiescent strain in the structure. The change in the quiescent strain, when an intruder adds weight to the structure provides the alarm mechanism. The basic theory of force sensors is covered to lay the foundation for this application. In this paper, how this basic theory is applied to security sensors is discussed, and how this class of sensors is applicable to security at Department of Energy facilities is covered. Several applications are described for strain gauges as security sensors. Test results are presented from a six-month test conducted at a Department of Energy facility using the strain gauge to monitor overhead lines crossing a security perimeter. Monitoring these overhead lines with strain gauges is valuable because the cost is much less than the cost to bury the lines

  20. Strain engineering of graphene: a review

    Science.gov (United States)

    Si, Chen; Sun, Zhimei; Liu, Feng

    2016-02-01

    Graphene has intrigued the science community by many unique properties not found in conventional materials. In particular, it is the strongest two-dimensional material ever measured, being able to sustain reversible tensile elastic strain larger than 20%, which yields an interesting possibility to tune the properties of graphene by strain and thus opens a new field called ``straintronics''. In this article, the current progress in the strain engineering of graphene is reviewed. We first summarize the strain effects on the electronic structure and Raman spectra of graphene. We then highlight the electron-phonon coupling greatly enhanced by the biaxial strain and the strong pseudomagnetic field induced by the non-uniform strain with specific distribution. Finally, the potential application of strain-engineering in the self-assembly of foreign atoms on the graphene surface is also discussed. Given the short history of graphene straintronics research, the current progress has been notable, and many further advances in this field are expected.

  1. Generalizing the Fermi velocity of strained graphene from uniform to nonuniform strain

    OpenAIRE

    Oliva-Leyva, M.; Naumis, Gerardo G.

    2014-01-01

    The relevance of the strain-induced Dirac point shift to obtain the appropriate anisotropic Fermi velocity of strained graphene is demonstrated. Then a critical revision of the available effective Dirac Hamiltonians is made by studying in detail the limiting case of a uniform strain. An effective Dirac Hamiltonian for nonuniform strain is thus reported, which takes into account all strain-induced effects: changes in the nearest-neighbor hopping parameters, the reciprocal lattice deformation a...

  2. A Method to Measure Reference Strain in FBG Strain Sensor Interrogation System Involving Actuators

    OpenAIRE

    Rajan, Ginu; Semenova, Yuliya; Wu, Qiang; Farrell, Gerald; Wang, Pengfei

    2007-01-01

    A method for reference strain measurement for FBG strain sensor in the testing stage while applying strain using actuators like piezo translators or micro screw is introduced. Unlike conventional methods of surface mounting, in our method the strain gauge is affixed directly to the optical fibre, which allows it to use with systems where the strain is applied directly using actuators while testing the FBG sensing system. Different bonding techniques were tested and a comparison with the resul...

  3. Sequence of mitochondrial DNA cytochrome oxidase II in Cryptopygus nanjiensis and Phylogeny of Apterygota

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The mitochondrial cytochrome oxidase II (Co II) from four different apterygotens Cryptopygus nanjiensis (Collembola), Neanura latior (Collembola), Gracilentulus maijiawensis (Protura) and Lepidocampa weberi (Diplura) were sequenced. Their A+T content, number of nucleotide substitutions, TV/TV ratio, and Tamura-Nei's distance were calculated. A series of phylogenetic trees were constructed by parsimony and distance methods using a crustacean Artemia franciscana as outgroup. Finally the evolutionary trend A+T content of CO II genetic divergence and phylogenetic relationship of apterygotan groups were discussed.

  4. Sequence of mitochondrial DNA cytochrome oxidase II in Cryptopygus nanjiensis and Phylogeny of Apterygota

    Institute of Scientific and Technical Information of China (English)

    邵红光; 张亚平; 柯欣; 岳巧云; 尹文英

    2000-01-01

    The mitochondrial cytochrome oxidase II (Co II) from four different apterygotens Cryptopygus nanjiensis (Collembola), Neanura latior (Collembola), Gracilentulus maijiawensis (Protura) and Lepidocampa weberi (Diplura) were sequenced. Their A+T content, number of nucleotide substitutions, TV/TV ratio, and Tamura-Nei’s distance were calculated. A series of phylogenetic trees were constructed by parsimony and distance methods using a crustacean Artemia franciscana as outgroup. Finally the evolutionary trend A+T content of CO II genetic divergence and phylogenetic relationship of apterygotan groups were discussed.

  5. Sequence of mitochondrial DNA cytochrome oxidase Ⅱ in Cryptopygus nanjiensis and Phylogeny of Apterygota

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The mitochondrial cytochrome oxidase Ⅱ (Co Ⅱ) from four different apterygotens Cryptopygus nanjiensis (Collembola), Neanura latior (Collembola), Gracilentulus maijiawensis (Protura) and Lepidocampa weberi (Diplura) were sequenced. Their A+T content, number of nucleotide substitutions, TV/TV ratio, and Tamura-Nei's distance were calculated. A series of phylogenetic trees were constructed by parsimony and distance methods using a crustacean Artemia franciscana as outgroup. Finally the evolutionary trend A+T content of CO Ⅱ genetic divergence and phylogenetic relationship of apterygotan groups were discussed.

  6. Alimento vivo como alternativa en la dieta de larvas y juveniles de Pterophyllum scalare (Lichtenstein, 1823)

    OpenAIRE

    J. Luna-Figueroa; Z. T. de J. Vargas; T. J. Figueroa

    2010-01-01

    La nutrición en los estadios iniciales de los peces constituye uno de los principales problemas de cultivo, debido a que es la etapa en la que se presenta la mayor mortalidad. En el presente estudio se evaluó, como alternativa en la alimentación de larvas y juveniles de Pterophyllum scalare, el efecto de tres alimentos vivos (Moina wierzejski, Artemia franciscana y Panagrellus redivivus) y un alimento comercial (Aquarian Tropical Flakes) sobre la tasa específica de crecimiento (TEC) y la sobr...

  7. Effect of repeated insertions of curved sequences in DNA plasmids: a light-scattering study

    Science.gov (United States)

    Beretta, Stefano; Chirico, Giuseppe; Baldini, Giancarlo; Kapp, U.; Badaracco, G.

    1993-06-01

    The effect of the insertion of different amounts (from 0 to 6) of the curved sequence AluI in pUC18m plasmid (2686 base pairs, bp) is studied by dynamic light scattering. This sequence is a highly repeated 113 base pairs long sequence from Artemia Franciscana shrimp. A 30% compaction of the plasmids containing 2 and 6 adjacent AluI sequences compared to pUC8 plasmid (2717 bp) is observed. Furthermore the behavior of the translational diffusion coefficient Dt versus the number of adjacent AluI insertion is not monotonic.

  8. Índice de desarrollo y supervivencia de larvas del camarón azul Litopenaeus stylirostris (Stimpson, 1871), alimentadas con diferentes concentraciones de Chaetoceros calcitrans (Paulsen)

    OpenAIRE

    Daniel E Godínez; Arnulfo H Díaz; María del C Gallo

    2005-01-01

    Se llevaron a cabo ensayos alimenticios con larvas del camarón azul (Litopenaeus stylirostris) utilizando cuatro diferentes concentraciones de la microalga Chaetoceroscalcitrans (30000, 60000, 90000 y 120000 cél/ml), con una concentración constante por tratamiento de 10000 cél/ml de Tetraselmis suecica y seis nauplios por ml de Artemia franciscana recién eclosionada. El período de prueba se inició a partir del sub estadio zoea 1 y concluyó hasta la aparición de misis 3. En cada ensayo fueron...

  9. A Brine Shrimp Bioassay for Measuring Toxicity and Remediation of Chemicals

    Science.gov (United States)

    Lieberman, Marya

    1999-12-01

    A bioassay using Artemia franciscana (brine shrimp) was adapted to measure the toxicity of household chemicals. One project is described in which students collect dose-response curves for seven commercial flea-killing products. Next, groups of students researched the insecticidal ingredients of the flea products. On the basis of the structures of the active ingredients, they chose remediation methods to make the flea product less toxic to brine shrimp; procedures included copper-catalyzed hydrolysis, adsorption onto activated charcoal, bleach treatment, and photodegradation. No special equipment or supplies are necessary for the bioassay other than the brine shrimp eggs, which can be obtained at any aquarium store.

  10. Global arrest of translation during invertebrate quiescence.

    OpenAIRE

    Hofmann, G E; Hand, S C

    1994-01-01

    Comparing the translational capacities of cell-free systems from aerobically developing embryos of the brine shrimp Artemia franciscana vs. quiescent embryos has revealed a global arrest of protein synthesis. Incorporation rates of [3H]leucine by lysates from 4-h anoxic embryos were 8% of those from aerobic (control) embryos, when assayed at the respective pH values measured for each treatment in vivo. Exposure of embryos to 4 h of aerobic acidosis (elevated CO2 in the presence of oxygen) sup...

  11. Application of capsule type strain gage and fiber optic grating strain sensor for measurement of strain under irradiation environment

    International Nuclear Information System (INIS)

    In Japan Atomic Energy Research Institute, in-pile strain measurement techniques have been developing by using JMTR. In order to evaluate the performance of capsule type strain gage and fiber optic grating sensor under irradiation environment, the heat-up tests in electric furnace before irradiation and in-pile tests were performed. As for capsule type strain gage, it is found that gage factor almost did not change and both its electric resistance and strain output decreased by irradiation effect. A correlation was found between the change ratio of the electric resistance of the capsule type strain gage and fast neutron fluence. As for fiber optic grating sensor, it is possible to measure strain under irradiation environment below 1x1023 n/m2 (E>1 MeV) by this sensor, because in-pile temperature characteristic was in agreement with out-of-pile test results. (author)

  12. Modeling competition between yeast strains

    Science.gov (United States)

    de Gee, Maarten; van Mourik, Hilda; de Visser, Arjan; Molenaar, Jaap

    2016-04-01

    We investigate toxin interference competition between S. cerevisiae colonies grown on a solid medium. In vivo experiments show that the outcome of this competition depends strongly on nutrient availability and cell densities. Here we present a new model for S. cerevisiae colonies, calculating the local height and composition of the colonies. The model simulates yeast colonies that show a good fit to experimental data. Simulations of colonies that start out with a homogeneous mixture of toxin producing and toxin sensitive cells can display remarkable pattern formation, depending on the initial ratio of the strains. Simulations in which the toxin producing and toxin sensitive species start at nearby positions clearly show that toxin production is advantageous.

  13. Determining Micromechanical Strain in Nitinol

    Energy Technology Data Exchange (ETDEWEB)

    Strasberg, Matthew; /SLAC

    2006-09-27

    Nitinol is a superelastic alloy made of equal parts nickel and titanium. Due to its unique shape memory properties, nitinol is used to make medical stents, lifesaving devices used to allow blood flow in occluded arteries. Micromechanical models and even nitinol-specific finite element analysis (FEA) software are insufficient for unerringly predicting fatigue and resultant failure. Due to the sensitive nature of its application, a better understanding of nitinol on a granular scale is being pursued through X-ray diffraction techniques at the Stanford Synchrotron Radiation Laboratory (SSRL) at the Stanford Linear Accelerator Center (SLAC). Through analysis of powder diffraction patterns of nitinol under increasing tensile loads, localized strain can be calculated. We compare these results with micromechanical predictions in order to advance nitinol-relevant FEA tools. From this we hope to gain a greater understanding of how nitinol fatigues under multi-axial loads.

  14. Job Strain in Shift and Daytime Workers.

    Science.gov (United States)

    Knutsson; Nilsson

    1997-07-01

    Cross-sectional questionnaire data were used to compare the levels of job strain in shift and daytime workers. Job strain was measured according to Karasek's Demands/Discretion model. Four occupational groups were included: drivers, industrial workers, policemen/watchmen, and cooks. The study subjects were a random sample of 508 daytime workers and 418 shift workers. Job demand did not differentiate between shift and daytime workers, comparing groups broken down by gender and by occupation. The daytime workers reported higher levels of job strain than the shift workers, and women experienced a higher level of job strain than did men. Multiple linear regression analysis showed that only occupational group and gender predicted job strain level. Shiftwork was not significantly associated with job strain in the regression model.

  15. The many shades of prion strain adaptation.

    Science.gov (United States)

    Baskakov, Ilia V

    2014-01-01

    In several recent studies transmissible prion disease was induced in animals by inoculation with recombinant prion protein amyloid fibrils produced in vitro. Serial transmission of amyloid fibrils gave rise to a new class of prion strains of synthetic origin. Gradual transformation of disease phenotypes and PrP(Sc) properties was observed during serial transmission of synthetic prions, a process that resembled the phenomenon of prion strain adaptation. The current article discusses the remarkable parallels between phenomena of prion strain adaptation that accompanies cross-species transmission and the evolution of synthetic prions occurring within the same host. Two alternative mechanisms underlying prion strain adaptation and synthetic strain evolution are discussed. The current article highlights the complexity of the prion transmission barrier and strain adaptation and proposes that the phenomenon of prion adaptation is more common than previously thought.

  16. Effect of strain rate and temperature at high strains on fatigue behavior of SAP alloys

    DEFF Research Database (Denmark)

    Blucher, J.T.; Knudsen, Per; Grant, N.J.

    1968-01-01

    Fatigue behavior of three SAP alloys of two nominal compositions (7 and 13% Al2O3) was studied in terms of strain rate and temperature at high strains; strain rate had no effect on life at 80 F, but had increasingly greater effect with increasing temperature above 500 F; life decreased with decre......Fatigue behavior of three SAP alloys of two nominal compositions (7 and 13% Al2O3) was studied in terms of strain rate and temperature at high strains; strain rate had no effect on life at 80 F, but had increasingly greater effect with increasing temperature above 500 F; life decreased...

  17. Investigation of Electronic Devices for Strain Measurement

    Directory of Open Access Journals (Sweden)

    Ričardas Masiulionis

    2011-08-01

    Full Text Available Importance of strain measuring for safety of buildings is shown. The strain monitoring should be one of the buildings security systems. Often used balanced and non-balanced Wheatstone bridge strain measurement methods are analyzed. The Wheatstone bridge method with feedback is improved. A new method based on small resistance changes by the digital balancing currents is presented. Computer and experimental models of measurement are investigated. The received results confirm theoretical assumptions.Article in Lithuanian

  18. Aggregation and distribution of strains in microparasites.

    OpenAIRE

    Lord, C. C.; Barnard, B.; Day, K; Hargrove, J. W.; McNamara, J J; Paul, R E; Trenholme, K; Woolhouse, M. E.

    1999-01-01

    Recent research has shown that many parasite populations are made up of a number of epidemiologically distinct strains or genotypes. The implications of strain structure or genetic diversity for parasite population dynamics are still uncertain, partly because there is no coherent framework for the interpretation of field data. Here, we present an analysis of four published data sets for vector-borne microparasite infections where strains or genotypes have been distinguished: serotypes of Afri...

  19. Nonlinear strain gradient elastic thin shallow shells

    OpenAIRE

    Lazopoulos, K.A.

    2011-01-01

    Abstract The governing equilibrium equations for strain gradient elastic thin shallow shells are derived, considering non-linear strains and linear constitutive strain gradient elastic relations. Adopting Kirchhoff's theory of thin shallow structures, the equilibrium equations, along with the boundary conditions, are formulated through a variational procedure. It turns out that new terms are introduced, indicating the importance of the cross-section area in bending of thin plates. ...

  20. Diversity among Streptomyces Strains Causing Potato Scab

    OpenAIRE

    Doering-Saad, Christiane; Kämpfer, Peter; Manulis, Shulamit; Kritzman, Giora; Schneider, Jörg; Zakrzewska-Czerwinska, Jolanta; Schrempf, Hildgund; Barash, Isaac

    1992-01-01

    Eighty Streptomyces isolates, including 35 potato scab-inducing strains and 12 reference strains of Streptomyces scabies, were physiologically characterized by a total of 329 miniaturized tests. Overall similarities of all strains were determined by numerical taxonomy, with the unweighted average linkage (UPGMA) algorithm and simple matching (Ssm) and Jaccard (Sj) coefficients used as measures for similarity. Three cluster groups (A to C) were defined at a similarity level of 80.1% (Ssm); the...

  1. Strain rate sensitivity of automotive sheet steels : influence of plastic strain, strain rate, temperature, microstructure, bake hardening and pre-strain

    OpenAIRE

    Larour, Patrick

    2010-01-01

    This experimental work shows the different parameters influencing the strain rate sensitivity behaviour of automotive sheet steel grades in crash conditions. Most investigations have been performed in the strain rate range [0,001-200/s] and temperature range [233-373K] with servohydraulic tensile testing machines. Additional Split-Hopkinson bar testing results up to 1000/s have also been included at room temperature. The focus has been laid on the “apparent” strain rate sensitivity, determine...

  2. Film germanium strain gauges for cryogenic temperatures

    International Nuclear Information System (INIS)

    Strain-measuring characteristics of strain gauges (SG) based on germanium films on gallium arsenide designed for operation in 4-100 K temperature interval and strain range ε∼(±0.3%) are presented. SG are characterized by weak temperature dependences of resistance and strain sensitivity in the temperature range measured. It is shown that in the low-temperature region SG based on heteroepitaxial germanium films on gallium arsenide are no worse than the best domestic and foreign semiconducting and metal SG and are perspective for cryogenic object diagnostics under magnetic field effect

  3. High strain rate damage of Carrara marble

    Science.gov (United States)

    Doan, Mai-Linh; Billi, Andrea

    2011-10-01

    Several cases of rock pulverization have been observed along major active faults in granite and other crystalline rocks. They have been interpreted as due to coseismic pervasive microfracturing. In contrast, little is known about pulverization in carbonates. With the aim of understanding carbonate pulverization, we investigate the high strain rate (c. 100 s-1) behavior of unconfined Carrara marble through a set of experiments with a Split Hopkinson Pressure Bar. Three final states were observed: (1) at low strain, the sample is kept intact, without apparent macrofractures; (2) failure is localized along a few fractures once stress is larger than 100 MPa, corresponding to a strain of 0.65%; (3) above 1.3% strain, the sample is pulverized. Contrary to granite, the transition to pulverization is controlled by strain rather than strain rate. Yet, at low strain rate, a sample from the same marble displayed only a few fractures. This suggests that the experiments were done above the strain rate transition to pulverization. Marble seems easier to pulverize than granite. This creates a paradox: finely pulverized rocks should be prevalent along any high strain zone near faults through carbonates, but this is not what is observed. A few alternatives are proposed to solve this paradox.

  4. Diversity among Streptomyces Strains Causing Potato Scab.

    Science.gov (United States)

    Doering-Saad, C; Kämpfer, P; Manulis, S; Kritzman, G; Schneider, J; Zakrzewska-Czerwinska, J; Schrempf, H; Barash, I

    1992-12-01

    Eighty Streptomyces isolates, including 35 potato scab-inducing strains and 12 reference strains of Streptomyces scabies, were physiologically characterized by a total of 329 miniaturized tests. Overall similarities of all strains were determined by numerical taxonomy, with the unweighted average linkage (UPGMA) algorithm and simple matching (S(sm)) and Jaccard (S(j)) coefficients used as measures for similarity. Three cluster groups (A to C) were defined at a similarity level of 80.1% (S(sm)); these groups contained 14 clusters and 24 unclustered strains defined at a similarity level of 86.5% (S(sm)). Cluster group A contained strains phenotypically related to S. griseus or S. exfoliatus, whereas cluster group B contained strains which were phenotypically related to S. violaceus or S. rochei. The majority of the pathogenic isolates and reference strains were assigned to S. violaceus (57%) and S. griseus (22%). A DNA probe derived from the rRNA operon of S. coelicolor IMET 40271 was used to detect restriction fragment length polymorphisms (RELPs) among 40 pathogenic and nonpathogenic Streptomyces isolates. Southern blots revealed a high degree of diversity among the pathogenic strains tested. No significant correlation between numerical classification and RFLP grouping of Streptomyces strains could be revealed. The results obtained suggest that RFLP data are of minor importance in classification of Streptomyces species and that genes for pathogenicity determinants are spread among different Streptomyces species by mobilizable elements. PMID:16348823

  5. Control of surface wettability via strain engineering

    Science.gov (United States)

    Xiong, Wei; Liu, Jefferson Zhe; Zhang, Zhi-Liang; Zhen, Quan-Shui

    2013-08-01

    Reversible control of surface wettability has wide applications in lab-on-chip systems, tunable optical lenses, and microfluidic tools. Using a graphene sheet as a sample material and molecular dynamic simulations, we demonstrate that strain engineering can serve as an effective way to control the surface wettability. The contact angles θ of water droplets on a graphene vary from 72.5° to 106° under biaxial strains ranging from -10% to 10% that are applied on the graphene layer. For an intrinsic hydrophilic surface (at zero strain), the variation of θ upon the applied strains is more sensitive, i.e., from 0° to 74.8°. Overall the cosines of the contact angles exhibit a linear relation with respect to the strains. In light of the inherent dependence of the contact angle on liquid-solid interfacial energy, we develop an analytic model to show the cos θ as a linear function of the adsorption energy E ads of a single water molecule over the substrate surface. This model agrees with our molecular dynamic results very well. Together with the linear dependence of E ads on biaxial strains, we can thus understand the effect of strains on the surface wettability. Thanks to the ease of reversibly applying mechanical strains in micro/nano-electromechanical systems, we believe that strain engineering can be a promising means to achieve the reversibly control of surface wettability.

  6. Conduction band structure and electron mobility in uniaxially strained Si via externally applied strain in nanomembranes

    Energy Technology Data Exchange (ETDEWEB)

    Chen Feng [Xi' an Jiaotong University, Xi' an, Shaanxi 710049 (China); Euaruksakul, Chanan; Himpsel, F J; Lagally, Max G [University of Wisconsin-Madison, Madison, WI 53706 (United States); Liu Zheng; Liu Feng, E-mail: lagally@engr.wisc.edu [University of Utah, Salt Lake City, UT 84112 (United States)

    2011-08-17

    Strain changes the band structure of semiconductors. We use x-ray absorption spectroscopy to study the change in the density of conduction band (CB) states when silicon is uniaxially strained along the [1 0 0] and [1 1 0] directions. High stress can be applied to silicon nanomembranes, because their thinness allows high levels of strain without fracture. Strain-induced changes in both the sixfold degenerate {Delta} valleys and the eightfold degenerate L valleys are determined quantitatively. The uniaxial deformation potentials of both {Delta} and L valleys are directly extracted using a strain tensor appropriate to the boundary conditions, i.e., confinement in the plane in the direction orthogonal to the straining direction, which correspond to those of strained CMOS in commercial applications. The experimentally determined deformation potentials match the theoretical predictions well. We predict electron mobility enhancement created by strain-induced CB modifications.

  7. A comparison of eastern North American seismic strain-rates to glacial rebound strain-rates

    Science.gov (United States)

    James, Thomas S.; Bent, Allison L.

    1994-01-01

    Glacial rebound strain-rates computed using a simple Laurentide glacial loading model are of the order of 10(exp -9) per year within the region of glaciation and extending several hundred kilometers beyond. The horizontal strain-rates receive approximately equal contributions from horizontal and vertical velocities, a consequence of the spherical geometry adopted for the Earth model. In the eastern United States and southeastern Canada the computed strain-rates are 1-3 orders of magnitude greater than an estimate of the average seismic strain-rate (Anderson, 1986) and approximately 1 order of magnitude greater than predicted erosional strain-rates. The predicted glacial rebound strain-rates are not, in general, oriented in such a way as to augment the observed state of deviatoric stress, possibly explaining why the seismic strain-rates are much smaller than the glacial rebound strain-rates. An exception to this may be seismically active regions in the St. Lawrence valley.

  8. Predicting creep rupture from early strain data

    International Nuclear Information System (INIS)

    To extend creep life modelling from classical rupture modelling, a robust and effective parametric strain model has been developed. The model can reproduce with good accuracy all parts of the creep curve, economically utilising the available rupture models. The resulting combined model can also be used to predict rupture from the available strain data, and to further improve the rupture models. The methodology can utilise unfailed specimen data for life assessment at lower stress levels than what is possible from rupture data alone. Master curves for creep strain and rupture have been produced for oxygen-free phosphorus-doped (OFP) copper with a maximum testing time of 51,000 h. Values of time to specific strain at given stress (40-165 MPa) and temperature (125-350 deg. C) were fitted to the models in the strain range of 0.1-38%. With typical inhomogeneous multi-batch creep data, the combined strain and rupture modelling involves the steps of investigation of the data quality, extraction of elastic and creep strain response, rupture modelling, data set balancing and creep strain modelling. Finally, the master curves for strain and rupture are tested and validated for overall fitting efficiency. With the Wilshire equation as the basis for the rupture model, the strain model applies classical parametric principles with an Arrhenius type of thermal activation and a power law type of stress dependence for the strain rate. The strain model also assumes that the processes of primary and secondary creep can be reasonably correlated. The rupture model represents a clear improvement over previous models in the range of the test data. The creep strain information from interrupted and running tests were assessed together with the rupture data investigating the possibility of rupture model improvement towards lower stress levels by inverse utilisation of the combined rupture based strain model. The developed creep strain model together with the improved rupture model is

  9. The Stress-Strain Condition Estimation of Detail in Crack Tip by Integral Strain Gauges

    Science.gov (United States)

    Syzrantsev, V.; Syzrantseva, K.

    2016-04-01

    The paper considers the task of stress-strain condition calculation of experimental sample in fatigue crack tip on weld boundary at its cyclic deforming. For this task decision authors use the information obtained by original means of cyclic strains measurement: Integral Strain Gauges. The results of carried experimental researches are compared with data of stress-strain condition estimation of detail in crack tip calculated by Finish Element Method.

  10. Calculation of the stress-strain stiffness matrix for given strains in an inelastic material

    Energy Technology Data Exchange (ETDEWEB)

    Friedrich, C.M.

    1978-01-01

    In the implicit method of non-linear analysis of stiffness matrices of finite elements, deflection fields and hence strains are assumed known at one stage of the calculations. A procedure is developed to calculate the stress-strain stiffness matrix from the strains without iteration of the stress components when the material is inelastic.

  11. Strain localization band width evolution by electronic speckle pattern interferometry strain rate measurement

    Energy Technology Data Exchange (ETDEWEB)

    Guelorget, Bruno [Institut Charles Delaunay-LASMIS, Universite de technologie de Troyes, FRE CNRS 2848, 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)], E-mail: bruno.guelorget@utt.fr; Francois, Manuel; Montay, Guillaume [Institut Charles Delaunay-LASMIS, Universite de technologie de Troyes, FRE CNRS 2848, 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)

    2009-04-15

    In this paper, electronic speckle pattern interferometry strain rate measurements are used to quantify the width of the strain localization band, which occurs when a sheet specimen is submitted to tension. It is shown that the width of this band decreases with increasing strain. Just before fracture, this measured width is about five times wider than the shear band and the initial sheet thickness.

  12. Job strain and time to pregnancy

    DEFF Research Database (Denmark)

    Hjollund, N H; Jensen, Tina Kold; Bonde, J P;

    1998-01-01

    The association between fertility and job strain defined as high job demands and low job control has not previously been studied. A follow-up study was conducted with prospective collection of information on job strain among women, achievement of pregnancy, and potential confounding variables....

  13. Deformation strain inhomogeneity in columnar grain nickel

    DEFF Research Database (Denmark)

    Wu, G.L.; Godfrey, A.; Juul Jensen, D.;

    2005-01-01

    A method is presented for determination of the local deformation strain of individual grains in the bulk of a columnar grain sample. The method, based on measurement of the change in grain area of each grain, is applied to 12% cold rolled nickel. Large variations are observed in the local strain...

  14. Nanocomposite Strain Gauges Having Small TCRs

    Science.gov (United States)

    Gregory, Otto; Chen, Ximing

    2009-01-01

    Ceramic strain gauges in which the strain-sensitive electrically conductive strips made from nanocomposites of noble metal and indium tin oxide (ITO) are being developed for use in gas turbine engines and other power-generation systems in which gas temperatures can exceed 1,500 F (about 816 C). In general, strain gauges exhibit spurious thermally induced components of response denoted apparent strain. When temperature varies, a strain-gauge material that has a nonzero temperature coefficient of resistance (TCR) exhibits an undesired change in electrical resistance that can be mistaken for the change in resistance caused by a change in strain. It would be desirable to formulate straingauge materials having TCRs as small as possible so as to minimize apparent strain. Most metals exhibit positive TCRs, while most semiconductors, including ITO, exhibit negative TCRs. The present development is based on the idea of using the negative TCR of ITO to counter the positive TCRs of noble metals and of obtaining the benefit of the ability of both ITO and noble metals to endure high temperatures. The noble metal used in this development thus far has been platinum. Combinatorial libraries of many ceramic strain gauges containing nanocomposites of various proportions of ITO and platinum were fabricated by reactive co-sputtering from ITO and platinum targets onto alumina- and zirconia-based substrates mounted at various positions between the targets.

  15. High-Temperature Resistance Strain Gauges

    Science.gov (United States)

    Lei, Jih-Fen

    1994-01-01

    Resistance strain gauges developed for use at high temperatures in demanding applications like testing aircraft engines and structures. Measures static strains at temperatures up to 800 degrees C. Small and highly reproducible. Readings corrected for temperature within small tolerances, provided temperatures measured simultaneously by thermocouples or other suitable devices. Connected in wheatstone bridge.

  16. A Natural Vaccine Candidate Strain Against Cholera

    Institute of Scientific and Technical Information of China (English)

    LIUYAN-QING; QIGUO-MING; 等

    1995-01-01

    El Tor Vibrio cholerae(EVC)strains may be classified into two kinds-epidemigenic(EEVC)strains and non-epidemigenic(NEEVC)strains-based on a phage-biotyping system.A large number of EEVC strains have been screened for toxigenic and putative colonization attributes.One such naturally occurring strain(designated IEM101)has been found which is devoid of genes encoding cholera toxin(CT),accessory cholera enterotoxin(ACE),zonula occludens toxin(ZOT),but possesses RS1 sequences and toixn-coregulated pilus A gene(tcpA)although tcpA is poorly expressed.It expresses type B pili but does not posses type C pili.It is an El Tor Ogawa strain and does not cause fluid accumulation in rabbit ileal loop tests.Active immunization of rabbits with strain IEM101 elicited good protection against challenge with virulent strains of V.cholerae Ol.Oral administration cased no side effects in 15 human volunteers.colonized the gut for four to ten days and elicited good immune responses.

  17. Surfactin production by strains of Bacillus mojavensis

    Science.gov (United States)

    Bacillus mojavensis, RRC101 is an endophytic bacterium patented for control of fungal diseases in maize and other plants. DNA fingerprint analysis of the rep-PCR fragments of 35 B. mojavensis and 4 B. subtilis strains using the Diversilab genotyping system revealed genotypic distinctive strains alon...

  18. Surface instabilities during straining of anisotropic materials

    DEFF Research Database (Denmark)

    Legarth, Brian Nyvang; Richelsen, Ann Bettina

    2006-01-01

    The development of instabilities in traction-free surfaces is investigated numerically using a unit cell model. Full finite strain analyses are conducted using isotropic as well as anisotropic yield criteria and both plane strain tension and compression are considered. In the load range of tension...

  19. Snowball: Strain aware gene assembly of Metagenomes

    NARCIS (Netherlands)

    Gregor, I.; Schoenhuth, A.; McHardy, A.C.

    2015-01-01

    Gene assembly is an important step in functional analysis of shotgun metagenomic data. Nonetheless, strain aware assembly remains a challenging task, as current assembly tools often fail to distinguish among strain variants or require closely related reference genomes of the studied species to be av

  20. Whole genome sequences of four Brucella strains.

    Science.gov (United States)

    Ding, Jiabo; Pan, Yuanlong; Jiang, Hai; Cheng, Junsheng; Liu, Taotao; Qin, Nan; Yang, Yi; Cui, Buyun; Chen, Chen; Liu, Cuihua; Mao, Kairong; Zhu, Baoli

    2011-07-01

    Brucella melitensis and Brucella suis are intracellular pathogens of livestock and humans. Here we report four genome sequences, those of the virulent strain B. melitensis M28-12 and vaccine strains B. melitensis M5 and M111 and B. suis S2, which show different virulences and pathogenicities, which will help to design a more effective brucellosis vaccine. PMID:21602346

  1. On fracture in finite strain gradient plasticity

    DEFF Research Database (Denmark)

    Martínez Pañeda, Emilio; Niordson, Christian Frithiof

    2016-01-01

    In this work a general framework for damage and fracture assessment including the effect of strain gradients is provided. Both mechanism-based and phenomenological strain gradient plasticity (SGP) theories are implemented numerically using finite deformation theory and crack tip fields are...... investigated. Differences and similarities between the two approaches within continuum SGP modeling are highlighted and discussed. Local strain hardening promoted by geometrically necessary dislocations (GNDs) in the vicinity of the crack leads to much higher stresses, relative to classical plasticity...... predictions. These differences increase significantly when large strains are taken into account, as a consequence of the contribution of strain gradients to the work hardening of the material. The magnitude of stress elevation at the crack tip and the distance ahead of the crack where GNDs significantly alter...

  2. Dark field electron holography for strain measurement

    Energy Technology Data Exchange (ETDEWEB)

    Beche, A., E-mail: armand.beche@fei.com [CEA-Grenoble, INAC/SP2M/LEMMA, F-38054 Grenoble (France); Rouviere, J.L. [CEA-Grenoble, INAC/SP2M/LEMMA, F-38054 Grenoble (France); Barnes, J.P.; Cooper, D. [CEA-LETI, Minatec Campus, F-38054 Grenoble (France)

    2011-02-15

    Dark field electron holography is a new TEM-based technique for measuring strain with nanometer scale resolution. Here we present the procedure to align a transmission electron microscope and obtain dark field holograms as well as the theoretical background necessary to reconstruct strain maps from holograms. A series of experimental parameters such as biprism voltage, sample thickness, exposure time, tilt angle and choice of diffracted beam are then investigated on a silicon-germanium layer epitaxially embedded in a silicon matrix in order to obtain optimal dark field holograms over a large field of view with good spatial resolution and strain sensitivity. -- Research Highlights: {yields} Step by step explanation of the dark field electron holography technique. {yields} Presentation of the theoretical equations to obtain quantitative strain map. {yields} Description of experimental parameters influencing dark field holography results. {yields} Quantitative strain measurement on a SiGe layer embedded in a silicon matrix.

  3. Review of graphene-based strain sensors

    Institute of Scientific and Technical Information of China (English)

    Zhao Jing; Zhang Guang-Yu; Shi Dong-Xia

    2013-01-01

    In this paper,we review various types of graphene-based strain sensors.Graphene is a monolayer of carbon atoms,which exhibits prominent electrical and mechanical properties and can be a good candidate in compact strain sensor applications.However,a perfect graphene is robust and has a low piezoresistive sensitivity.So scientists have been driven to increase the sensitivity using different kinds of methods since the first graphene-based strain sensor was reported.We give a comprehensive review of graphene-based strain sensors with different structures and mechanisms.It is obvious that graphene offers some advantages and has potential for the strain sensor application in the near future.

  4. Irreducible decomposition of strain gradient tensor in isotropic strain gradient elasticity

    CERN Document Server

    Lazar, Markus

    2016-01-01

    In isotropic strain gradient elasticity, we decompose the strain gradient tensor into its irreducible pieces under the n-dimensional orthogonal group O(n). Using the Young tableau method for traceless tensors, four irreducible pieces (n>2), which are canonical, are obtained. In three dimensions, the strain gradient tensor can be decomposed into four irreducible pieces with 7+5+3+3 independent components whereas in two dimensions, the strain gradient tensor can be decomposed into three irreducible pieces with 2+2+2 independent components. The knowledge of these irreducible pieces is extremely useful when setting up constitutive relations and strain energy.

  5. Strain relaxation in nano-patterned strained-Si/SiGe heterostructure on insulator

    International Nuclear Information System (INIS)

    In order to evaluate the strain stability, arrays of strained Si/SiGe nano-stripes and nano-pillars were fabricated by Electron-Beam Lithography (EBL) and Reactive-Ion Etching (RIE). The strain relaxation in the patterned strained Si on SiGe-on-insulator (SGOI) was investigated by high-resolution UV micro-Raman spectroscopy. The Raman measurements before and after patterning indicate that most of the strain in the top strained Si is maintained until scaling down to 300 nm, and relaxation of <15% is observed in pillars with a dimension of 150 nm x 150 nm. In the nano-patterned heterostructure strained Si/SiGe, the observed relaxation is small, which is mainly attributed to the fully relaxed and dislocation-free SiGe virtual substrate fabricated by modified Ge condensation.

  6. Thermoresistance in radioresistant strains of 'Drosophila nebulosa'

    International Nuclear Information System (INIS)

    The detection of thermoresistance in radioresistant strains of 'D. nebulosa' is described, as well as some conclusions on the genetic nature of these differences are presented. The strains used in this experiment were MF 204, from 'Morro de Ferro', in Pocos de Caldas (MG) (one of the biggest radioactive anomalies in the world) whose radioresistance is due to its additive genetic components (Kratz, 1973 and 1975); 85(87) R, an induced radioresistant strain; and MF K a control 'pooled' strain obtained near 'Morro do Ferro'. Survival tests, 72 hours after temperature shocks, performed in the interval of 360C to 390C showed a decreasing gradient of thermoresistance with the following regression coefficients: MF 204 b=-5,4; 85(87)R b=-7,2 and MF K b=-7,9. Bifactorial analysis (strains and sexes) performed at 380C and 390C confirmed differences among strains (P<01 and P<0,5, respectively) suggesting a poligenic control of the thermoresistance. Consitent and verified relations among strains, being simultaneously resistant to different kinds of mutagenic factors, are considered evidence of the existence of general mechanisms in mutagenic control. Therefore, the results, together with results of Tsukamoto, Ogaki and Kikkawa 1957, Ogaki 1962 and Nakashima-Tanaka 1966, Parsons 1969, add to the hypotheses of the existence of general mechanisms in mutagenic control

  7. Strain mapping analysis of textile composites

    Science.gov (United States)

    Ivanov, Dmitry; Ivanov, Sergey; Lomov, Stepan; Verpoest, Ignaas

    2009-03-01

    The focus of the work is meso-scale analysis (scale level of the fabric unit cell) of textile composite deformation and failure. The surface strain measurement is used for: (1) experimental investigation, which includes study of strain distribution at various stages of deformation, plasticity detection, damage initiation; (2) numerical validation of the correspondent finite element (FE) models. Two examples are considered: carbon-epoxy triaxial-braided and glass polypropylene-woven composite. The surface strain measurement (by digital image correlation technique) accompanies the tensile tests, aiming at: (1) elastic anisotropic constants characterisation, (2) study of non-linear material behaviour (for the thermoplastic composite), (3) control of homogeneity of the macro-strain distribution, and (4) analysis of damage initiation in brittle composites. Validation of meso-FE models by strain measurements encounters difficulties arising from (1) resolution of the strain measurements, (2) irregularities of the initial structure such as random layer nesting, ply interaction, and deviation of yarns from their theoretical position, which affects the measured strain fields. The paper discusses these difficulties and demonstrates a qualitative agreement with the FE analysis of idealised composite configurations.

  8. Piezoelectric strain sensor/actuator rosettes

    International Nuclear Information System (INIS)

    In-plane anisotropy in the linear piezoelectric constitutive law for [011]c cut and poled PMN–0.29PT is demonstrated to enable its use as a sensor/actuator rosette. The equations for a 0°/45°/90° rosette are developed using the conditions of coupling between the in-plane strain of the crystal and a substrate, and zero out-of-plane stress on the crystal (plane stress conditions in the crystals). The crystals are bonded to a substrate aluminum plate that is instrumented with strain gages next to the crystals. The plate is subjected to bending about different axes and the resulting electric displacement change of the crystals is monitored. The strain components calculated using the change of electric displacement are compared with the strain components measured using strain gages. This sensor/actuator rosette approach is demonstrated to enable both sensing principal strain components and actuating principal strains in an electronically controllable direction. (fast track communication)

  9. PHYLOGENETIC STUDY OF SOME STRAINS OF DUNALIELLA

    Directory of Open Access Journals (Sweden)

    Duc Tran

    2013-01-01

    Full Text Available Dunaliella strains were isolated from a key site for salt production in Vietnam (Vinh Hao, Binh Thuan province. The strains were identified based on Internal Transcribed Spacer (ITS markers. The phylogenetic tree revealed these strains belong to the clades of Dunaliella salina and Dunaliella viridis. Results of this study confirm the ubiquitous nature of Dunaliella and suggest that strains of Dunaliella salina might be acquired locally worldwide for the production of beta-carotene. The identification of these species infers the presence of other Dunaliella species (Dunaliella tertiolecta, Dunaliella primolecta, Dunaliella parva, but further investigation would be required to confirm their presence in Vietnam. We anticipate the physiological and biochemical characteristics of these local species will be compared with imported strains in a future effort. This will facilitate selection of strains with the best potential for exploitation in the food, aquaculture and biofuel industries. The Dunaliella strains isolated and identified in this study are maintained at the Laboratory of Algal Biotechnology, International University and will be made available for research and educational institutions.

  10. Heterogeneity of inelastic strain during creep of Carrara marble: Microscale strain measurement technique

    Science.gov (United States)

    Quintanilla-Terminel, Alejandra; Evans, Brian

    2016-08-01

    We combined the split cylinder technique with microfabrication technology to observe strain heterogeneities that were produced during high-pressure transient creep of Carrara marble. Samples were patterned with a custom-designed grid of markers spaced 10 µm apart and containing an embedded coordinate system. The microscale strain measurement (MSSM) technique described here allowed us to analyze the local strain distribution with unprecedented detail over large regions. The description of the strain field is a function of the area over which strain is being computed. The scale at which the strain field can be considered homogeneous can provide insight into the deformation processes taking place. At 400-500°C, when twinning production is prolific, we observe highly strained bands that span several grains. One possible cause for the multigrain bands is the need to relieve strain incompatibilities that result when twins impinge on neighboring grains. At 600-700°C, the strain fields are still quite heterogeneous, and local strain varies substantially within grains and near grain boundaries, but the multigrain slip bands are not present. Deformation is concentrated in much smaller areas within grains and along some grain boundaries. The disappearance of the multigrain slip bands occurs when the deformation conditions allow additional slip systems to be activated. At 600°C, when the total strain is varied from 0.11 to 0.36, the spatial scale of the heterogeneity does not vary, but there are increases in the standard deviation of the distribution of local strains normalized by the total strain; thus, we conclude that the microstructure does not achieve a steady state in this strain interval.

  11. On lower order strain gradient plasticity theories

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Hutchinson, J. W.

    2002-01-01

    By way of numerical examples, this paper explores the nature of solutions to a class of strain gradient plasticity theories that employ conventional stresses, equilibrium equations and boundary conditions. Strain gradients come into play in these modified conventional theories only to alter...... the tangential moduli governing increments of stress and strain. It is shown that the modification is far from benign from a mathematical standpoint, changing the qualitative character of solutions and leading to a new type of localization that appears to be unphysical....

  12. Revisiting the gauge fields of strained graphene

    OpenAIRE

    Iorio, Alfredo; Pais, Pablo(Centro de Estudios Científicos (CECS), Casilla, 1469 , Valdivia, Chile)

    2015-01-01

    We show that, when graphene is only subject to strain, the spin connection gauge field that arises plays no measurable role, but when intrinsic curvature is present and strain is small, spin connection dictates most the physics. We do so by showing that the Weyl field associated with strain is a pure gauge field and no constraint on the $(2+1)$-dimensional spacetime appears. On the other hand, for constant intrinsic curvature that also gives a pure-gauge Weyl field, we find a classical manife...

  13. STRAIN ANALYSIS OF LATERAL EXTRUSION PROCESS

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The strain distribution of equal-cross section lateral extrusion(ECSLE) has been simulated by finite element method. Considering the effect of friction and the width of sample, the simulation results are very close to the reality. The simulated results showed that, around the corner of die, the strain is distributed by sharp layers, and the gradient of the layers is very large, which means that the deformation is just plane shear deformation; the larger the width of sample or the smaller the friction, the more uniform the strain distribution is.

  14. Construction of Killer Wine Yeast Strain

    OpenAIRE

    Seki, Tetsuji; Choi, Eon-Ho; Ryu, Dewey

    1985-01-01

    A double-stranded RNA plasmid which confers the superkiller phenotype was transferred into a wine yeast (Montrachet strain 522) and its leucine-requiring derivative (strain 694) by cytoduction, using the protoplast fusion technique. The killer wine yeast constructed completely suppressed the growth of killer-sensitive strains of Saccharomyces cerevisiae in yeast extract-peptone-glucose medium at pH 4.5, whereas the killer effect was somewhat decreased at pH 3.5. The wine yeast harboring the k...

  15. Semiconductor strain metrology principles and applications

    CERN Document Server

    Wong, Terence KS

    2012-01-01

    This book surveys the major and newly developed techniques for semiconductor strain metrology. Semiconductor strain metrology has emerged in recent years as a topic of great interest to researchers involved in thin film and nanoscale device characterization. This e-book employs a tutorial approach to explain the principles and applications of each technique specifically tailored for graduate students and postdoctoral researchers. Selected topics include optical, electron beam, ion beam and synchrotron x-ray techniques. Unlike earlier references, this e-book specifically discusses strain metrol

  16. Stability of germanene under tensile strain

    KAUST Repository

    Kaloni, Thaneshwor P.

    2013-09-01

    The stability of germanene under biaxial tensile strain and the accompanying modifications of the electronic properties are studied by density functional theory. The phonon spectrum shows that up to 16% strain the germanene lattice is stable, where the Dirac cone shifts towards higher energy and hole-doped Dirac states are achieved. The latter is due to weakening of the Ge-Ge bonds and reduction of the s-p hybridization. Our calculated Grüneisen parameter shows a similar dependence on the strain as reported for silicene (which is different from that of graphene). © 2013 Elsevier B.V. All rights reserved.

  17. Pseudomagnetic fields and triaxial strain in graphene

    DEFF Research Database (Denmark)

    Settnes, Mikkel; Power, Stephen; Jauho, Antti-Pekka

    2016-01-01

    -binding calculations of single pseudomagnetic dots in extended graphene sheets confirm these predictions, and are also used to study the effect of rotating the strain direction with respect to the underlying graphene lattice, and varying the size of the pseudomagnetic dot.......Pseudomagnetic fields, which can result from nonuniform strain distributions, have received much attention in graphene systems due to the possibility of mimicking real magnetic fields with magnitudes of greater than 100 T. We examine systems with such strains confined to finite regions...

  18. Strain gage balances and buffet gages

    Science.gov (United States)

    Ferris, A. T.

    1983-01-01

    One-piece strain gage force balances were developed for use in the National Transonic Facility (NTF). This was accomplished by studying the effects of the cryogenic environment on materials, strain gages, cements, solders, and moisture proofing agents, and selecting those that minimized strain gage output changes due to temperature. In addition, because of the higher loads that may be imposed by the NTF, these balances are designed to carry a larger load for a given diameter than conventional balances. Full cryogenic calibrations were accomplished, and wind tunnel results that were obtained from the Langley 0-3-Meter Transonic Cryogenic Tunnel were used to verify laboratory test results.

  19. Ductile Damage Evolution and Strain Path Dependency

    Science.gov (United States)

    Tasan, C. C.; Hoefnagels, J. M. P.; Peerlings, R. H. J.; Geers, M. G. D.; ten Horn, C. H. L. J.; Vegter, H.

    2007-04-01

    Forming limit diagrams are commonly used in sheet metal industry to define the safe forming regions. These diagrams are built to define the necking strains of sheet metals. However, with the rise in the popularity of advance high strength steels, ductile fracture through damage evolution has also emerged as an important parameter in the determination of limit strains. In this work, damage evolution in two different steels used in the automotive industry is examined to observe the relationship between damage evolution and the strain path that is followed during the forming operation.

  20. Self-diffusion in compressively strained Ge

    International Nuclear Information System (INIS)

    Under a compressive biaxial strain of ∼ 0.71%, Ge self-diffusion has been measured using an isotopically controlled Ge single-crystal layer grown on a relaxed Si0.2Ge0.8 virtual substrate. The self-diffusivity is enhanced by the compressive strain and its behavior is fully consistent with a theoretical prediction of a generalized activation volume model of a simple vacancy mediated diffusion, reported by Aziz et al.[Phys. Rev. B 73, 054101 (2006)]. The activation volume of (-0.65±0.21) times the Ge atomic volume quantitatively describes the observed enhancement due to the compressive biaxial strain very well.

  1. A new radial strain and strain rate estimation method using autocorrelation for carotid artery

    Science.gov (United States)

    Ye, Jihui; Kim, Hoonmin; Park, Jongho; Yeo, Sunmi; Shim, Hwan; Lim, Hyungjoon; Yoo, Yangmo

    2014-03-01

    Atherosclerosis is a leading cause of cardiovascular disease. The early diagnosis of atherosclerosis is of clinical interest since it can prevent any adverse effects of atherosclerotic vascular diseases. In this paper, a new carotid artery radial strain estimation method based on autocorrelation is presented. In the proposed method, the strain is first estimated by the autocorrelation of two complex signals from the consecutive frames. Then, the angular phase from autocorrelation is converted to strain and strain rate and they are analyzed over time. In addition, a 2D strain image over region of interest in a carotid artery can be displayed. To evaluate the feasibility of the proposed radial strain estimation method, radiofrequency (RF) data of 408 frames in the carotid artery of a volunteer were acquired by a commercial ultrasound system equipped with a research package (V10, Samsung Medison, Korea) by using a L5-13IS linear array transducer. From in vivo carotid artery data, the mean strain estimate was -0.1372 while its minimum and maximum values were -2.961 and 0.909, respectively. Moreover, the overall strain estimates are highly correlated with the reconstructed M-mode trace. Similar results were obtained from the estimation of the strain rate change over time. These results indicate that the proposed carotid artery radial strain estimation method is useful for assessing the arterial wall's stiffness noninvasively without increasing the computational complexity.

  2. Dynamic Force Measurement with Strain Gauges

    Science.gov (United States)

    Lee, Bruce E.

    1974-01-01

    Discusses the use of four strain gauges, a Wheatstone bridge, and an oscilloscope to measure forces dynamically. Included is an example of determining the centripetal force of a pendulum in a general physics laboratory. (CC)

  3. Design parameters for borehole strain instrumentation

    Science.gov (United States)

    Gladwin, Michael T.; Hart, Rhodes

    1985-01-01

    The response of a borehole strain meter to hydrostatic and shear deformations in an isotropic medium is calculated to facilitate optimum instrument design and produce instrument response factors for parameters typically encountered in installed instruments. Results for an empty borehole are first compared with results for an instrument in intimate contact with the surrounding rock. The effects of the grout used to install the instrument are then examined. Where possible, analytic forms for the response factors are given. Results for typical installations are then presented in graphical form for optimizing instrument design in an environment of known elastic parameters. Alternatively, the results may be applied in the measurement of unknown strain signals, to correct for instrument response or to provide in-situ estimates of the elastic properties of the environment by examination of observed strain response to known strain signals.

  4. Five challenges in modelling interacting strain dynamics

    Directory of Open Access Journals (Sweden)

    Paul S. Wikramaratna

    2015-03-01

    Full Text Available Population epidemiological models where hosts can be infected sequentially by different strains have the potential to help us understand many important diseases. Researchers have in recent years started to develop and use such models, but the extra layer of complexity from multiple strains brings with it many technical challenges. It is therefore hard to build models which have realistic assumptions yet are tractable. Here we outline some of the main challenges in this area. First we begin with the fundamental question of how to translate from complex small-scale dynamics within a host to useful population models. Next we consider the nature of so-called “strain space”. We describe two key types of host heterogeneities, and explain how models could help generate a better understanding of their effects. Finally, for diseases with many strains, we consider the challenge of modelling how immunity accumulates over multiple exposures.

  5. Screening of Trichoderma strains tolerant to benzimidazole

    Institute of Scientific and Technical Information of China (English)

    LIU Kai-qi; XIANG Mei-mei; LIU Ren; ZENG Yong-san; ZHOU Hong-zi; YU Jin-feng; JIANG Xin-yin; ZHANG Yue-li

    2004-01-01

    @@ The screening of isolates and the assay of biocontrol mechanisms of Trichoderma were studied systematically in laboratory and greenhouse in vivo. The proteins tolerant to benzimidazole in Trichoderma strains were purified, and their physical and chemical properties were detected. Compared their biological activities in vitro and vivo in greenhouse, nine biocontrol strains (including Ty- 10-2, LTR-2, Tj-5-1, Tj-5-4, Ty- 11-1, Tj-11-3, Ty- 11-3, Tj-3-3-2, Tj-3-3-4) were screened. These biocontrol strains had faster rates of growth and higher inhibition to gray mould (Bortrytis cinerea),and the inhibition was stable. The effects of controlling gray mould in greenhouse with the screened Trichoderma strains were 70 % and 50 % in vivo.

  6. High Strain Rate Characterisation of Composite Materials

    DEFF Research Database (Denmark)

    Eriksen, Rasmus Normann Wilken

    The high strain rate characterisation of FRP materials present the experimenter with a new set of challenges in obtaining valid experimental data. These challenges were addressed in this work with basis in classic wave theory. The stress equilibrium process for linear elastic materials, as fibre......-reinforced polymers, were considered, and it was first shown that the loading history controls equilibrium process. Then the High-speed servo-hydraulic test machine was analysed in terms its ability to create a state of constant strain rate in the specimen. The invertible inertial forces in the load train prevented...... for testing fibre-reinforced polymers due to their elastic behaviour and low strain to failure. This is problematic as the High-speed servo-hydraulic test machine closes the gap between quasi-static tests rates and lower strain rates, which are achievable with the Split Hopkinson Pressure Bar. The Split...

  7. [Improvement of Trichoderma strains for biocontrol].

    Science.gov (United States)

    Benítez, T; Rey, M; Delgado-Jarana, J; Rincón, A M; Limón, M C

    2000-03-01

    The use of the fungal genus Trichoderma to control fungal plant diseases is a promising alternative to the use of chemical compounds. The aim of this work has been to obtain Trichoderma strains with improved capacity as biological control agents. To do so, the hydrolytic capacity on fungal cell walls of strains of the fungus Trichoderma harzianum has been increased. On one hand, transformation experiments with genes which coded for chitinases and glucanases have been carried out in T. harzianumstra ins. On the other hand, the medium composition has also been modified in order to eliminate proteolytic degradation of some of the overproduced enzymes. Finally, hybrid chitinolytic enzymes with substrate-binding domains have been produced as an alternative to obtain improved biocontrol strains. The transformant strains, when compared with the wild type, showed improved antifungal capacity against the phytopathogenic fungus Rhizoctonia solani, in in vitro experiments. PMID:15762779

  8. Strain Rate Induced Amorphization in Metallic Nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Y.; Cagin, T.; Goddard, W.A. III [Materials and Process Simulation Center, California Institute of Technology, Pasadena, California 91125 (United States); Ikeda, H.; Samwer, K.; Johnson, W.L. [Keck Laboratory of Engineering Materials, California Institute of Technology, Pasadena, California 91125 (United States)

    1999-04-01

    Using molecular dynamics simulations with a many-body force field, we studied the deformation of single crystal Ni and NiCu random alloy nanowires subjected to uniform strain rates but kept at 300thinspthinspK. For all strain rates, the Ni nanowire is elastic up to 7.5{percent} strain with a yield stress of 5.5thinspthinspGPa, far above that of bulk Ni. At high strain rates, we find that for both systems the crystalline phase transforms continuously to an amorphous phase, exhibiting a dramatic change in atomic short-range order and a near vanishing of the tetragonal shear elastic constant perpendicular to the tensile direction. This amorphization which occurs directly from the homogeneous, elastically deformed system with no chemical or structural inhomogeneities exhibits a new mode of amorphization. {copyright} {ital 1999} {ital The American Physical Society}

  9. 3D Morphing Using Strain Field Interpolation

    Institute of Scientific and Technical Information of China (English)

    Han-Bing Yan; Shi-Min Hu; Ralph R Martin

    2007-01-01

    In this paper, we present a new technique based on strain fields to carry out 3D shape morphing for applicationsin computer graphics and related areas.Strain is an important geometric quantity used in mechanics to describe the deformation of objects.We apply it in a novel way to analyze and control deformation in morphing.Using position vector fields, the strain field relating source and target shapes can be obtained.By interpolating this strain field between zero and a final desired value we can obtain the position field for intermediate shapes.This method ensures that the 3D morphing process is smooth.Locally, volumes suffer minimal distortion, and no shape jittering or wobbling happens: other methods do not necessarily have these desirable properties.We also show how to control the method so that changes of shape (in particular, size changes) vary linearly with time.

  10. Five challenges in modelling interacting strain dynamics

    DEFF Research Database (Denmark)

    Wikramaratna, Paul S; Kurcharski, Adam; Gupta, Sunetra;

    2015-01-01

    Population epidemiological models where hosts can be infected sequentially by different strains have the potential to help us understand many important diseases. Researchers have in recent years started to develop and use such models, but the extra layer of complexity from multiple strains brings...... with it many technical challenges. It is therefore hard to build models which have realistic assumptions yet are tractable. Here we outline some of the main challenges in this area. First we begin with the fundamental question of how to translate from complex small-scale dynamics within a host to...... useful population models. Next we consider the nature of so-called “strain space”. We describe two key types of host heterogeneities, and explain how models could help generate a better understanding of their effects. Finally, for diseases with many strains, we consider the challenge of modelling how...

  11. Strain Gauges Mounted To Retain Calibration

    Science.gov (United States)

    Butler, Barry L.

    1993-01-01

    Silicon-based semiconductor strain gauges mounted in such way they retain original calibration for several years instead of few months. Improvement effected by bonding gauges to ceramic substrates with glasses instead of epoxies as adhesives.

  12. Broken Bones, Sprains, and Strains (For Parents)

    Science.gov (United States)

    ... 5 Things to Know About Zika & Pregnancy Broken Bones, Sprains, and Strains KidsHealth > For Parents > Broken Bones, ... home. What to Do: For a Suspected Broken Bone: Do not move a child whose injury involves ...

  13. Strain imaging by Bragg edge neutron transmission

    CERN Document Server

    Santisteban, J R; Fitzpatrick, M E; Steuwer, A; Withers, P J; Daymond, M R; Johnson, M W; Rhodes, N; Schooneveld, E M

    2002-01-01

    The Bragg edges appearing in the transmitted time-of-flight spectra of polycrystalline materials have been recorded using a two-dimensional array of detectors. Subsequent analysis has enabled maps of the elastic strain to be produced.

  14. Review of strain buckling: analysis methods

    International Nuclear Information System (INIS)

    This report represents an attempt to review the mechanical analysis methods reported in the literature to account for the specific behaviour that we call buckling under strain. In this report, this expression covers all buckling mechanisms in which the strains imposed play a role, whether they act alone (as in simple buckling under controlled strain), or whether they act with other loadings (primary loading, such as pressure, for example). Attention is focused on the practical problems relevant to LMFBR reactors. The components concerned are distinguished by their high slenderness ratios and by rather high thermal levels, both constant and variable with time. Conventional static buckling analysis methods are not always appropriate for the consideration of buckling under strain. New methods must therefore be developed in certain cases. It is also hoped that this review will facilitate the coding of these analytical methods to aid the constructor in his design task and to identify the areas which merit further investigation

  15. Energy Harvesting Wireless Strain Networks Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Prime Research LC (PPLC) and Virginia Tech (VT) propose to develop an energy harvesting wireless strain node technology that utilizes single-crystal piezoelectric...

  16. Superinfection Behaviors on Scale-Free Networks with Competing Strains

    Science.gov (United States)

    Wu, Qingchu; Small, Michael; Liu, Huaxiang

    2013-02-01

    This paper considers the epidemiology of two strains ( I, J) of a disease spreading through a population represented by a scale-free network. The epidemiological model is SIS and the two strains have different reproductive numbers. Superinfection means that strain I can infect individuals already infected with strain J, replacing the strain J infection. Individuals infected with strain I cannot be infected with strain J. The model is set up as a system of ordering differential equations and stability of the disease free, marginal strain I and strain J, and coexistence equilibria are assessed using linear stability analysis, supported by simulations. The main conclusion is that superinfection, as modeled in this paper, can allow strain I to coexist with strain J even when it has a lower basic reproductive number. Most strikingly, it can allow strain I to persist even when its reproductive number is less than 1.

  17. Information about the Current Strain of Clostridium difficile

    Science.gov (United States)

    ... treatment of this epidemic strain different? How does fluoroquinolone resistance affect management of this strain? What should ... guidelines on internet) Top of page How does fluoroquinolone resistance affect management of this strain? Increased fluoroquinolone ...

  18. Conductive lithographic film fabricated resistive strain gauges

    OpenAIRE

    Hay, GI; Evans, PSA; Harrison, DJ; Southee, DJ; Simpson, G; Harrey, PM

    2003-01-01

    This paper reports progress in sensor fabrication by the conductive lithographic film (CLF) printing process. Work describing strain sensitive structures manufactured using a modified printing process and conductive inks are addressed. The performance of a 'single ink' strain sensitive structure when printed on six alternative polymer substrates (GlossArt, PolyArt, Teslin, Mylar C, Mylar and Kapton) is analysed. Though not intending to compete with conventional gauges in high tolerance measur...

  19. Characterization of lithographically printed resistive strain gauges

    OpenAIRE

    Hay, G.I.; Evans, P.S.A.; Harrison, D J; Southee, D; Simpson, G; Harrey, P.M.

    2005-01-01

    This paper reports progress in sensor fabrication by the conductive lithographic film (CLF) printing process. Work describing strain-sensitive structures manufactured using a modified printing process and conductive inks is addressed. The performance of a "single-ink" strain-sensitive structure when printed on six alternative substrates (GlossArt, PolyArt, Teslin, Mylar C, Melinex, and Kapton) is analyzed. Though not intending to compete with conventional gauges in high-tolerance measurement,...

  20. Hydraulic Calibrator for Strain-Gauge Balances

    Science.gov (United States)

    Skelly, Kenneth; Ballard, John

    1987-01-01

    Instrument for calibrating strain-gauge balances uses hydraulic actuators and load cells. Eliminates effects of nonparallelism, nonperpendicularity, and changes of cable directions upon vector sums of applied forces. Errors due to cable stretching, pulley friction, and weight inaccuracy also eliminated. New instrument rugged and transportable. Set up quickly. Developed to apply known loads to wind-tunnel models with encapsulated strain-gauge balances, also adapted for use in calibrating dynamometers, load sensors on machinery and laboratory instruments.

  1. Strain gauge for high temperature tests

    International Nuclear Information System (INIS)

    A strain gauge is described that is intended to measure longitudinal and lateral strains during tubular specimen loading by an axial force and internal pressure at test temperatures up to 1000 K. The use of the gauge for creep study of steel type Kh18N10T at 870 K under complex stress state is given as an example. Experimental data confirm the suitability of the gauge for the purpose mentioned and sufficient accuracy of parameters determined. 3 refs., 3 figs

  2. Elastic constants from microscopic strain fluctuations

    OpenAIRE

    Sengupta, Surajit; Nielaba, Peter; Rao, Madan; Binder, K.

    1999-01-01

    Fluctuations of the instantaneous local Lagrangian strain $\\epsilon_{ij}(\\bf{r},t)$, measured with respect to a static ``reference'' lattice, are used to obtain accurate estimates of the elastic constants of model solids from atomistic computer simulations. The measured strains are systematically coarse- grained by averaging them within subsystems (of size $L_b$) of a system (of total size $L$) in the canonical ensemble. Using a simple finite size scaling theory we predict the behaviour of th...

  3. Cranial bone morphometric study among mouse strains

    OpenAIRE

    Yamamura Ken-ichi; Kawakami Minoru

    2008-01-01

    Abstract Background Little is known about the molecular mechanism which regulates how the whole cranium is shaped. Mouse models currently available for genetic research include several hundreds of unique inbred strains and genetically engineered mutants. By cross comparing their genomic structures, we can elucidate the cause of any differences in the phenotype between two strains. The craniometry of subspecies, or closely related species, of mice provide a good systemic model to study the rel...

  4. A tunable strain sensor using nanogranular metals

    OpenAIRE

    Friedemann Völklein; Alexander Kaya; Jens Müller; Pintu Das; Heiko Reith; Fabrizio Porrati; Roland Sachser; Markus Baranowski; Christina Grimm; Schwalb, Christian H.; Michael Huth

    2010-01-01

    This paper introduces a new methodology for the fabrication of strain-sensor elements for MEMS and NEMS applications based on the tunneling effect in nano-granular metals. The strain-sensor elements are prepared by the maskless lithography technique of focused electron-beam-induced deposition (FEBID) employing the precursor trimethylmethylcyclopentadienyl platinum [MeCpPt(Me)3]. We use a cantilever-based deflection technique to determine the sensitivity (gauge factor) of the sensor element. W...

  5. FRP rupture strains in FRP wrapped columns

    OpenAIRE

    Li, Shiqing

    2012-01-01

    Applying lateral confinement to concrete columns using fibre-reinforced polymer (FRP) composites is a very promising technique. FRP rupture is the typical failure mode of FRP wrapped columns under axial compression. numerous experiments have shown that the FRP rupture strain in an FRP wrapped circular column is significantly lower than the FRP ultimate rupture strain determined from flat coupon test of FRP. Despite a large number of studies on the application of FRP confined columns, the mech...

  6. Digital Eye Strain Reduction Techniques: A Review

    OpenAIRE

    Preethi J Seegehalli

    2016-01-01

    Digital eye strain or computer vision syndrome (CVS) is caused when we spend considerable amount of time in staring at digital screens of desktop computer, laptop, e-readers, tablets and mobile phones. This paper discusses the different the causes for visual fatigue and digital eye strain reduction techniques like usage of optical glass, flicker free screen, color filtering, fuzzy logic based brightness adaption technique, bias lighting screens, optimizing monitor’s color temperature and Auto...

  7. Elastically Relaxed Free-standing Strained-Si Nanomembranes

    OpenAIRE

    Roberts, Michelle M.; Klein, Levente J.; Savage, Don E.; Slinker, Keith A.; Friesen, Mark; Celler, George; Eriksson, Mark A.; Lagally, Max G.

    2006-01-01

    Strain plays a critical role in the properties of materials. In silicon and silicon-germanium, strain provides a mechanism for control of both carrier mobility and band offsets. In materials integra-tion, strain is typically tuned through the use of dislocations and elemental composition. We demonstrate a versatile method to control strain, by fabricating membranes in which the final strain state is controlled by elastic strain sharing, i.e., without the formation of defects. We grow Si/SiGe ...

  8. Whole Genome Analysis of a Wine Yeast Strain

    OpenAIRE

    Hauser, Nicole C.; Kurt Fellenberg; Rosario Gil; Sonja Bastuck; Hoheisel, Jörg D; Pérez-Ortín, José E.

    2001-01-01

    Saccharomyces cerevisiae strains frequently exhibit rather specific phenotypic features needed for adaptation to a special environment. Wine yeast strains are able to ferment musts, for example, while other industrial or laboratory strains fail to do so. The genetic differences that characterize wine yeast strains are poorly understood, however. As a first search of genetic differences between wine and laboratory strains, we performed DNA-array analyses on the typical wine yeast strain T73 an...

  9. Strain rate patterns from dense GPS networks

    Directory of Open Access Journals (Sweden)

    M. Hackl

    2009-07-01

    Full Text Available The knowledge of the crustal strain rate tensor provides a description of geodynamic processes such as fault strain accumulation, which is an important parameter for seismic hazard assessment, as well as anthropogenic deformation. In the past two decades, the number of observations and the accuracy of satellite based geodetic measurements like GPS greatly increased, providing measured values of displacements and velocities of points. Here we present a method to obtain the full continuous strain rate tensor from dense GPS networks. The tensorial analysis provides different aspects of deformation, such as the maximum shear strain rate, including its direction, and the dilatation strain rate. These parameters are suitable to characterize the mechanism of the current deformation. Using the velocity fields provided by SCEC and UNAVCO, we were able to localize major active faults in Southern California and to characterize them in terms of faulting mechanism. We also show that the large seismic events that occurred recently in the study region highly contaminate the measured velocity field that appears to be strongly affected by transient postseismic deformation. Finally, we applied this method to coseismic displacement data of two earthquakes in Iceland, showing that the strain fields derived by these data provide important information on the location and the focal mechanism of the ruptures.

  10. Instrument for measuring fuel cladding strain

    International Nuclear Information System (INIS)

    Development work to provide instrumentation for the continuous measurement of strain of material specimens such as nuclear fuel cladding has shown that a microwave sensor and associated instrumentation hold promise. The cylindrical sensor body enclosing the specimen results in a coaxial resonator absorbing microwave energy at frequencies dependent upon the diameter of the specimen. Diametral changes of a microinch can be resolved with use of the instrumentation. Very reasonable values of elastic strain were measured at 750F and 10000F for an internally pressurized 20 percent C.W. 316 stainless steel specimen simulating nuclear fuel cladding. The instrument also indicated the creep strain of the same specimen pressurized at 6500 psi and at a temperature of 10000F for a period of 700 hours. Although the indicated strain appears greater than actual, the sensor/specimen unit experienced considerable oxidation even though an inert gas purge persisted throughout the test duration. By monitoring at least two modes of resonance, the measured strain was shown to be nearly independent of sensor temperature. To prevent oxidation, a second test was performed in which the specimen/sensor units were contained in an evacuated enclosure. The strain of the two prepressurized specimens as indicated by the microwave instrumentation agreed very closely with pre- and post-test measurements obtained with use of a laser interferometer

  11. 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.

  12. The mechanical consequences of load bearing in the equine third metacarpal across speed and gait: the nonuniform distributions of normal strain, shear strain, and strain energy density

    OpenAIRE

    Rubin, Clinton T.; Seeherman, Howard; Qin, Yi-Xian; Gross, Ted S.

    2013-01-01

    Distributions of normal strain, shear strain, and strain energy density (SED) were determined across the midshaft of the third metacarpal (MCIII, or cannon bone) of 3 adult thoroughbred horses as a function of speed and gait. A complete characterization of the mechanical demands of the bone made through the stride and from mild through the extremes of locomotion was possible by using three 3-element rosette strain gauges bonded at the diaphyseal midshaft of the MCIII and evaluating the strain...

  13. Strain rate measurement by Electronic Speckle Pattern Interferometry: A new look at the strain localization onset

    Energy Technology Data Exchange (ETDEWEB)

    Guelorget, Bruno [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)]. E-mail: bruno.guelorget@utt.fr; Francois, Manuel [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France); Vial-Edwards, Cristian [Departemento de Ingenieria Mecanica y Metalurgica, Pontificia Universidad Catolica de Chile, Vicuna Mackenna 4860, 6904411 Santiago (Chile); Montay, Guillaume [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France); Daniel, Laurent [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France); Lu, Jian [Universite de Technologie de Troyes (UTT), Laboratoire des Systemes Mecaniques et d' ingenierie Simultanee (LASMIS, CNRS FRE 2719), 12 rue Marie Curie, B.P. 2060, 10010 Troyes Cedex (France)

    2006-01-15

    In-plane Electronic Speckle Pattern Interferometry has been successfully used during tensile testing of semi-hard copper sheets in order to measure the strain rate. On one hand, heterogeneity in strain rate field has been found before the maximum of the tensile force ({epsilon} {sup t} {approx_equal} 19.4 and 25.4%, respectively). Thus, a localization phenomenon occurs before the classic Considere's criterion (dF = 0) for the diffuse neck initiation. On the other hand, strain rate measurement before fracture shows the moment where one of the two slip band systems becomes predominant, then strain concentrates in a small area, the shear band. Uncertainty evaluation has been carried out, which shows a very good accuracy of the total strain and the strain rate measurements.

  14. Strain fields adjacent to bone-implant interfaces: strain field analysis using digital image correlation techniques

    OpenAIRE

    Ribeiro, J. E.; Monteiro, J.; Lopes, H.; Vaz, M.A.P.; Guedes, R.M.

    2008-01-01

    When using conventional surface strain measurement techniques (e.g. strain gauges, dial gauges), the measurement of deformations within cancellous bone is frequently hampered by the material’s highly porous structure and poor mechanical properties. Although detailed strain maps derived from actual experimental data have the potential to resolve many questions concerning the mechanics of cancellous bone, the traditional method of producing maps through measurements with optical techniques has ...

  15. Inexpensive Implementation of Many Strain Gauges

    Science.gov (United States)

    Berkun, Andrew C.

    2010-01-01

    It has been proposed to develop arrays of strain gauges as arrays of ordinary metal film resistors and associated electronic readout circuitry on printed circuit boards or other suitable substrates. This proposal is a by-product of a development of instrumentation utilizing metal film resistors on printed-circuit boards to measure temperatures at multiple locations. In the course of that development, it was observed that in addition to being sensitive to temperature, the metal film resistors were also sensitive to strains in the printed-circuit boards to which they were attached. Because of the low cost of ordinary metal film resistors (typically strain gauges, possibly concentrated in small areas. For example, such an array could be designed for use as a computer keyboard with no moving parts, as a device for sensing the shape of an object resting on a surface, or as a device for measuring strains at many points on a mirror, a fuel tank, an airplane wing, or other large object. Ordinarily, the effect of strain on resistance would be regarded as a nuisance in a temperature-measuring application, and the effect of temperature on resistance would be regarded as a nuisance in a strain-measuring application. The strain-induced changes in resistance of the metal film resistors in question are less than those of films in traditional strain gauges. The main novel aspect of present proposal lies in the use of circuitry affording sufficient sensitivity to measure strain plus means for compensating for the effect of temperature. For an array of metal film resistors used as proposed, the readout circuits would include a high-accuracy analog-to-digital converter fed by a low noise current source, amplifier chain, and an analog multiplexer chain. Corrections would be provided by use of high-accuracy calibration resistors and a temperature sensor. By use of such readout circuitry, it would be possible to read the resistances of as many as 100 fixed resistors in a time interval

  16. True stress-strain curve acquisition for irradiated stainless steel including the range exceeding necking strain

    Science.gov (United States)

    Kamaya, Masayuki; Kitsunai, Yuji; Koshiishi, Masato

    2015-10-01

    True stress-strain curves were obtained for irradiated 316L stainless steel by a tensile test and by a curve estimation procedure. In the tensile test, the digital image correlation technique together with iterative finite element analysis was applied in order to identify curves for strain larger than the necking strain. The true stress-strain curves were successfully obtained for the strain of more than 0.4 whereas the necking strain was about 0.2 in the minimum case. The obtained true stress-strain curves were approximated well with the Swift-type equation including the post-necking strain even if the exponential constant n was fixed to 0.5. Then, the true stress-strain curves were estimated by a curve estimation procedure, which was referred to as the K-fit method. Material properties required for the K-fit method were the yield and ultimate strengths or only the yield strength. Some modifications were made for the K-fit method in order to improve estimation accuracy for irradiated stainless steels.

  17. Within-strain variation in behavior differs consistently between common inbred strains of mice.

    Science.gov (United States)

    Loos, Maarten; Koopmans, Bastijn; Aarts, Emmeke; Maroteaux, Gregoire; van der Sluis, Sophie; Verhage, Matthijs; Smit, August B

    2015-08-01

    Genetic and environmental factors interact throughout life and give rise to individual differences, i.e., individuality. The diversifying effect of environmental factors is counteracted by genetic mechanisms to yield persistence of specific features (robustness). Here, we compared robustness between cohorts of isogenic mice of eight different commonly used strains by analyzing to what extent environmental variation contributed to individuality in each of the eight genotypes, using a previously published dataset. Behavior was assessed in the home-cage, providing control over environmental factors, to reveal within-strain variability in numerous spontaneous behaviors. Indeed, despite standardization and in line with previous studies, substantial variability among mice of the same inbred strain was observed. Strikingly, across a multidimensional set of 115 behavioral parameters, several strains consistently ranked high in within-strain variability (DBA/2J, 129S1/Sv A/J and NOD/LtJ), whereas other strains ranked low (C57BL/6J and BALB/c). Strain rankings of within-strain variability in behavior were confirmed in an independent, previously published behavioral dataset using conventional behavioral tests administered to different mice from the same breeding colonies. Together, these show that genetically inbred mouse strains consistently differ in phenotypic robustness against environmental variation, suggesting that genetic factors contribute to variation in robustness. PMID:26123533

  18. Variation in the strain anisotropy of Zircaloy with temperature and strain

    International Nuclear Information System (INIS)

    Strain anisotropy was investigated at temperatures in the range 293 to 1117K in circular tensile specimens prepared from rolled Zircaloy-2 plate so that their tensile axes were parallel to and transverse to the rolling direction. The strain anisotropy factor for both types of specimen increased markedly in the high alpha phase region above 923K reaching a maximum at circa 1070K. Above this temperature in the alpha-plus-beta phase region the strain anisotropy decreased rapidly as the proportion of beta phase increased and was almost non-existent at 1173K. The strain anisotropy was markedly strain dependent, particularly in the high alpha phase region. The study was extended to Zircaloy-4 pressurized water reactor (PWR) 17 x 17 type fuel rod tubing specimens which were strained under biaxial conditions using cooling conditions which promoted uniform diametral strain over most of their lengths (circa 250 mm). In these circumstances the strain anisotropy is manifest by a reduction in length. Measurement of this change along with that in diameter and wall thickness produced data from which the strain anisotropy factor was calculated. The results, although influenced by additional factors discussed in the paper, were similar to those observed in the uniaxial Zircaloy-2 tensile tests. (author)

  19. A numerical method for determining the strain rate intensity factor under plane strain conditions

    Science.gov (United States)

    Alexandrov, S.; Kuo, C.-Y.; Jeng, Y.-R.

    2016-07-01

    Using the classical model of rigid perfectly plastic solids, the strain rate intensity factor has been previously introduced as the coefficient of the leading singular term in a series expansion of the equivalent strain rate in the vicinity of maximum friction surfaces. Since then, many strain rate intensity factors have been determined by means of analytical and semi-analytical solutions. However, no attempt has been made to develop a numerical method for calculating the strain rate intensity factor. This paper presents such a method for planar flow. The method is based on the theory of characteristics. First, the strain rate intensity factor is derived in characteristic coordinates. Then, a standard numerical slip-line technique is supplemented with a procedure to calculate the strain rate intensity factor. The distribution of the strain rate intensity factor along the friction surface in compression of a layer between two parallel plates is determined. A high accuracy of this numerical solution for the strain rate intensity factor is confirmed by comparison with an analytic solution. It is shown that the distribution of the strain rate intensity factor is in general discontinuous.

  20. The influence of strain rate and hydrogen on the plane-strain ductility of Zircaloy cladding

    Energy Technology Data Exchange (ETDEWEB)

    Link, T.M.; Motta, A.T.; Koss, D.A. [Pennsylvania State Univ., University Park, PA (United States)

    1998-03-01

    The authors studied the ductility of unirradiated Zircaloy-4 cladding under loading conditions prototypical of those found in reactivity-initiated accidents (RIA), i.e.: near plane-strain deformation in the hoop direction (transverse to the cladding axis) at room temperature and 300 C and high strain rates. To conduct these studies, they developed a specimen configuration in which near plane-strain deformation is achieved in the gage section, and a testing methodology that allows one to determine both the limit strain at the onset of localized necking and the fracture strain. The experiments indicate that there is little effect of strain rate (10{sup {minus}3} to 10{sup 2} s{sup {minus}1}) on the ductility of unhydrided Zircaloy tubing deformed under near plane-strain conditions at either room temperature or 300 C. Preliminary experiments on cladding containing 190 ppm hydrogen show only a small loss of fracture strain but no clear effect on limit strain. The experiments also indicate that there is a significant loss of Zircaloy ductility when surface flaws are present in the form of thickness imperfections.

  1. Elastocaloric cooling processes: The influence of material strain and strain rate on efficiency and temperature span

    Science.gov (United States)

    Schmidt, Marvin; Schütze, Andreas; Seelecke, Stefan

    2016-06-01

    This paper discusses the influence of material strain and strain rate on efficiency and temperature span of elastocaloric cooling processes. The elastocaloric material, a newly developed quaternary Ni-Ti-Cu-V alloy, is characterized at different maximum strains and strain rates. The experiments are performed with a specially designed test setup, which enables the measurement of mechanical and thermal process parameters. The material efficiency is compared to the efficiency of the Carnot process at equivalent thermal operation conditions. This method allows for a direct comparison of the investigated material with other caloric materials.

  2. Elastocaloric cooling processes: The influence of material strain and strain rate on efficiency and temperature span

    Directory of Open Access Journals (Sweden)

    Marvin Schmidt

    2016-06-01

    Full Text Available This paper discusses the influence of material strain and strain rate on efficiency and temperature span of elastocaloric cooling processes. The elastocaloric material, a newly developed quaternary Ni-Ti-Cu-V alloy, is characterized at different maximum strains and strain rates. The experiments are performed with a specially designed test setup, which enables the measurement of mechanical and thermal process parameters. The material efficiency is compared to the efficiency of the Carnot process at equivalent thermal operation conditions. This method allows for a direct comparison of the investigated material with other caloric materials.

  3. 葡萄糖和盐度对卤虫生长、养殖系统生物絮团形成及其微生物多样性的影响%EFFECTS OF GLUCOSE AND SALINITY ON ARTEMIA GROWTH, BIOFLOC FORMATION, AND MICROBIAL DIVERSITY IN CULTURE

    Institute of Scientific and Technical Information of China (English)

    王娇; 马灌楠; 邓元告; 隋丽英

    2015-01-01

    在零换水卤虫养殖系统中,研究葡萄糖和盐度对卤虫Artemia franciscana生长、卤水中生物絮团形成、水质及其微生物多样性的影响.实验设四组,每组三个平行,分别在盐度为50、100和150的养殖水体中添加葡萄糖(添加量随着卤虫的生长逐渐增加从每天12mg/L到37mg/L),对照组盐度为50且不添加葡萄糖.单位养殖水体为1L,卤虫起始密度约为1200ind/L,投喂浓缩杜氏藻Dunaliella viridis,养殖周期为20天.结果显示,添加葡萄糖可以显著提高生物絮团体积,降低水中的铵盐、亚硝酸盐、硝酸盐和总氮水平,提高卤虫总生物量(P<0.05).但随着盐度升高,卤虫生物量显著降低(P<0.05),亚硝酸盐和总氮水平显著升高(P<0.05),絮团体积有所升高.另外,葡萄糖添加和盐度对卤虫粗蛋白和脂肪酸含量无显著影响(P>0.05).PCR-DGGE分析表明,γ-变形菌纲(γ-proteobacterium)为生物絮团中优势菌群且以海洋细菌为主.与对照组相比,添加葡萄糖和升高盐度显著降低菌群丰富度指数(P<0.05),环境承载力下降.本研究结果为高盐环境条件下生物絮团的形成机理及其在卤虫人工养殖中的应用提供了参考.

  4. Mycobacterium tuberculosis strains exhibit differential and strain-specific molecular signatures in pulmonary epithelial cells.

    Science.gov (United States)

    Mvubu, Nontobeko Eunice; Pillay, Balakrishna; Gamieldien, Junaid; Bishai, William; Pillay, Manormoney

    2016-12-01

    Although pulmonary epithelial cells are integral to innate and adaptive immune responses during Mycobacterium tuberculosis infection, global transcriptomic changes in these cells remain largely unknown. Changes in gene expression induced in pulmonary epithelial cells infected with M. tuberculosis F15/LAM4/KZN, F11, F28, Beijing and Unique genotypes were investigated by RNA sequencing (RNA-Seq). The Illumina HiSeq 2000 platform generated 50 bp reads that were mapped to the human genome (Hg19) using Tophat (2.0.10). Differential gene expression induced by the different strains in infected relative to the uninfected cells was quantified and compared using Cufflinks (2.1.0) and MeV (4.0.9), respectively. Gene expression varied among the strains with the total number of genes as follows: F15/LAM4/KZN (1187), Beijing (1252), F11 (1639), F28 (870), Unique (886) and H37Rv (1179). A subset of 292 genes was commonly induced by all strains, where 52 genes were down-regulated while 240 genes were up-regulated. Differentially expressed genes were compared among the strains and the number of induced strain-specific gene signatures were as follows: F15/LAM4/KZN (138), Beijing (52), F11 (255), F28 (55), Unique (186) and H37Rv (125). Strain-specific molecular gene signatures associated with functional pathways were observed only for the Unique and H37Rv strains while certain biological functions may be associated with other strain signatures. This study demonstrated that strains of M. tuberculosis induce differential gene expression and strain-specific molecular signatures in pulmonary epithelial cells. Specific signatures induced by clinical strains of M. tuberculosis can be further explored for novel host-associated biomarkers and adjunctive immunotherapies. PMID:27497873

  5. Mycobacterium tuberculosis strains exhibit differential and strain-specific molecular signatures in pulmonary epithelial cells.

    Science.gov (United States)

    Mvubu, Nontobeko Eunice; Pillay, Balakrishna; Gamieldien, Junaid; Bishai, William; Pillay, Manormoney

    2016-12-01

    Although pulmonary epithelial cells are integral to innate and adaptive immune responses during Mycobacterium tuberculosis infection, global transcriptomic changes in these cells remain largely unknown. Changes in gene expression induced in pulmonary epithelial cells infected with M. tuberculosis F15/LAM4/KZN, F11, F28, Beijing and Unique genotypes were investigated by RNA sequencing (RNA-Seq). The Illumina HiSeq 2000 platform generated 50 bp reads that were mapped to the human genome (Hg19) using Tophat (2.0.10). Differential gene expression induced by the different strains in infected relative to the uninfected cells was quantified and compared using Cufflinks (2.1.0) and MeV (4.0.9), respectively. Gene expression varied among the strains with the total number of genes as follows: F15/LAM4/KZN (1187), Beijing (1252), F11 (1639), F28 (870), Unique (886) and H37Rv (1179). A subset of 292 genes was commonly induced by all strains, where 52 genes were down-regulated while 240 genes were up-regulated. Differentially expressed genes were compared among the strains and the number of induced strain-specific gene signatures were as follows: F15/LAM4/KZN (138), Beijing (52), F11 (255), F28 (55), Unique (186) and H37Rv (125). Strain-specific molecular gene signatures associated with functional pathways were observed only for the Unique and H37Rv strains while certain biological functions may be associated with other strain signatures. This study demonstrated that strains of M. tuberculosis induce differential gene expression and strain-specific molecular signatures in pulmonary epithelial cells. Specific signatures induced by clinical strains of M. tuberculosis can be further explored for novel host-associated biomarkers and adjunctive immunotherapies.

  6. Anisotropic nature of radially strained metal tubes

    Science.gov (United States)

    Strickland, Julie N.

    Metal pipes are sometimes swaged by a metal cone to enlarge them, which increases the strain in the material. The amount of strain is important because it affects the burst and collapse strength. Burst strength is the amount of internal pressure that a pipe can withstand before failure, while collapse strength is the amount of external pressure that a pipe can withstand before failure. If the burst or collapse strengths are exceeded, the pipe may fracture, causing critical failure. Such an event could cost the owners and their customers millions of dollars in clean up, repair, and lost time, in addition to the potential environmental damage. Therefore, a reliable way of estimating the burst and collapse strength of strained pipe is desired and valuable. The sponsor currently rates strained pipes using the properties of raw steel, because those properties are easily measured (for example, yield strength). In the past, the engineers assumed that the metal would be work-hardened when swaged, so that yield strength would increase. However, swaging introduces anisotropic strain, which may decrease the yield strength. This study measured the yield strength of strained material in the transverse and axial direction and compared them to raw material, to determine the amount of anisotropy. This information will be used to more accurately determine burst and collapse ratings for strained pipes. More accurate ratings mean safer products, which will minimize risk for the sponsor's customers. Since the strained metal has a higher yield strength than the raw material, using the raw yield strength to calculate burst and collapse ratings is a conservative method. The metal has even higher yield strength after strain aging, which indicates that the stresses are relieved. Even with the 12% anisotropy in the strained and 9% anisotropy in the strain aged specimens, the raw yield strengths are lower and therefore more conservative. I recommend that the sponsor continue using the raw

  7. Fast flexible electronics with strained silicon nanomembranes.

    Science.gov (United States)

    Zhou, Han; Seo, Jung-Hun; Paskiewicz, Deborah M; Zhu, Ye; Celler, George K; Voyles, Paul M; Zhou, Weidong; Lagally, Max G; Ma, Zhenqiang

    2013-01-01

    Fast flexible electronics operating at radio frequencies (>1 GHz) are more attractive than traditional flexible electronics because of their versatile capabilities, dramatic power savings when operating at reduced speed and broader spectrum of applications. Transferrable single-crystalline Si nanomembranes (SiNMs) are preferred to other materials for flexible electronics owing to their unique advantages. Further improvement of Si-based device speed implies significant technical and economic advantages. While the mobility of bulk Si can be enhanced using strain techniques, implementing these techniques into transferrable single-crystalline SiNMs has been challenging and not demonstrated. The past approach presents severe challenges to achieve effective doping and desired material topology. Here we demonstrate the combination of strained- NM-compatible doping techniques with self-sustained-strain sharing by applying a strain-sharing scheme between Si and SiGe multiple epitaxial layers, to create strained print-transferrable SiNMs. We demonstrate a new speed record of Si-based flexible electronics without using aggressively scaled critical device dimensions.

  8. Assessment of myocardial strain and strain rate by tissue doppler echocar-diography

    Directory of Open Access Journals (Sweden)

    Ekimova N.A.

    2013-03-01

    Full Text Available The objective of the article is to review the current data on the method of quantitative evaluation of cardiac mechanics — assessment of myocardial strain and strain rate according to the results of the tissue Doppler echocardiography and prospects of its clinical application.

  9. Development of the invar36 thin film strain gauge sensor for strain measurement

    International Nuclear Information System (INIS)

    This paper presents development of invar36 thin film strain gauges of various thicknesses ranging from 100 to 1400 Å for strain measurement. The strain gauges are deposited on microslides using the dc magnetron sputtering technique. Resistivity, temperature coefficient of resistance (TCR) and gauge factors of all gauges are measured and compared with each other. TCR is estimated by systematic annealing of gauges in vacuum and found as low as 190 ppm °C−1. A four-point bending setup is designed and fabricated to measure the gauge factors of all gauges. The gauge factor of relatively thinner strain gauge is found as high as 4.5 and for strain gauges with thickness greater than 500 Å gauge factor is found less than 2.5. The variations of gauge resistance with applied strain are studied in terms of linearity, hysteresis and repeatability. The developed strain gauges are connected in a full-bridge configuration and the output response to the applied strain is studied at different excitation voltages. (paper)

  10. Measurement of high temperature strain by the laser-speckle strain gauge

    Science.gov (United States)

    Yamaguchi, I.

    1984-01-01

    By using the laser-speckle strain gauge, the strain of metal at the temperature lower than 250 C is measured. The principle of the gauge is to measure the expansion or contraction of the fine structures of surface by detecting the resultant speckle displacement in an optoelectronic way, whereby the effect of rigid-body motion is automatically cancelled out with the aid of a differential detection system. A transportable apparatus was built and a comparison experiment performed with a resistance strain gauge at room temperature. It has a strain sensitivity of .00002, a gauge length smaller than 1 mm, and no upper limit in a range of strain measurement. In the measurement of high-temperature strain it is free from the need for a dummy gauge and insensitive to an electric drift effect. As examples of strain measurement at high-temperature, thermal expansion and contraction of a top of a soldering iron are measured. The interval of the measurement can be made at shortest 1.6 sec. and the change in the strain is clearly followed until the ultimate stationary temperature is reached.

  11. Validation of perceptual strain index to evaluate the thermal strain in experimental hot conditions

    Directory of Open Access Journals (Sweden)

    Habibollah Dehghan

    2015-01-01

    Conclusions: The research findings showed when there is no access to other forms of methods to evaluate the heat stress, it can be used the PeSI in evaluating the strain because of its favorable correlation with the thermal strain.

  12. Characterization of Integrated Optical Strain Sensors Based on Silicon Waveguides

    NARCIS (Netherlands)

    Westerveld, W.J.; Leinders, S.M.; Muilwijk, P.M.; Pozo, J.

    2013-01-01

    Microscale strain gauges are widely used in micro electro-mechanical systems (MEMS) to measure strains such as those induced by force, acceleration, pressure or sound. We propose all-optical strain sensors based on micro-ring resonators to be integrated with MEMS. We characterized the strain-induced

  13. ON STRAIN RATE SENSITIVITY OF BETA-TITANIUM ALLOYS

    OpenAIRE

    Kobayashi, A.; Takeda, N.; Ogihara, S.; Li, Y.

    1991-01-01

    Ti-15V-3Cr-3A1-3Sn beta-titanium alloys are subjected to 103/s tensile strain rate by the one bar method to investigate strain rate sensitivity. It is found that the ultimate strength, the total elongation and the absorbed energy, all increase with the increase in strain rate. Dynamical stress-strain curves are also obtained.

  14. Complete Genome Sequences of 17 Rapidly Growing Nontuberculous Mycobacterial Strains

    Science.gov (United States)

    Spilker, Theodore; LiPuma, John J.

    2016-01-01

    We report the complete genome sequences of 17 rapidly growing nontuberculous mycobacterial (NTM) strains, including 16 Mycobacterium abscessus complex strains and one M. immunogenum strain. These sequences add value to studies of the genetic diversity of rapidly growing NTM strains recovered from human specimens. PMID:27660787

  15. Complete Genome Sequences of 17 Rapidly Growing Nontuberculous Mycobacterial Strains.

    Science.gov (United States)

    Caverly, Lindsay J; Spilker, Theodore; LiPuma, John J

    2016-01-01

    We report the complete genome sequences of 17 rapidly growing nontuberculous mycobacterial (NTM) strains, including 16 Mycobacterium abscessus complex strains and one M. immunogenum strain. These sequences add value to studies of the genetic diversity of rapidly growing NTM strains recovered from human specimens. PMID:27660787

  16. ANISOTROPIC STRAIN-HARDENING IN POLYCRYSTALLINE COPPER AND ALUMINUM

    NARCIS (Netherlands)

    HESS, F

    1993-01-01

    A new viscoplastic model for the plastic stress-strain behaviour of f.c.c. metals is presented. In this model the strain hardening results from increasing dislocation densities. The observed stagnation of strain hardening after strain reversals is explained by a lowering of the increase in dislocati

  17. A new strain gage method for measuring the contractile strain ratio of Zircaloy tubing

    International Nuclear Information System (INIS)

    An improved strain gage method for determining the contractile strain ratio (CSR) of Zircaloy tubing was developed. The new method consists of a number of load-unload cyclings at approximately 0.2% plastic strain interval. With this method the CSR of Zircaloy-4 tubing could be determined accurately because it was possible to separate the plastic strains from the elastic strain involvement. The CSR values determined by use of the new method were in good agreement with those calculated from conventional post-test manual measurements. The CSR of the tubing was found to decrease with the amount of deformation during testing because of uneven plastic flow in the gage section. A new technique of inscribing gage marks by use of a YAG laser is discussed. (orig.)

  18. Strain hardening and ductility of iron: axisymmetric vs. plane strain elongation. Technical progress report

    Energy Technology Data Exchange (ETDEWEB)

    Langford, G.

    1979-05-01

    The strain hardening of iron at high strains in plane strain elongation (strip drawing) is shown to fall increasngly below that of drawn iron wires at true strains above 2. This makes it unnecessary to invoke shear band formation simultaneously as a strengthening mechanism and as a ductility reducing mechanism in the drawn strip. Rather, shear bands may be a weakening mechanism in all contexts. A set of specimens of interstitial-free iron deformed in three of the four main classifications of deformation symmetry (wire, strip, and chips, representing axisymmetric elongation, plane strain elongation, and pure shear) has been prepared in the form of mechanical test specimens and thin foils for high resolution selected area diffraction. A simple technique for rapid discovery of the <110> axis of foils of strongly textured bcc wire has been worked out.

  19. The asymptomatic bacteriuria Escherichia coli strain 83972 outcompetes uropathogenic E. coli strains in human urine

    DEFF Research Database (Denmark)

    Hancock, Viktoria; Ulett, G.C.; Schembri, M.A.;

    2006-01-01

    Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU). In contrast to uropathogenic E. coli (UPEC), which causes symptomatic urinary tract infections (UTI), very little is known about the mechanisms by which these strains colonize the human urinary tract...... to conventional therapy. Colonization with strain 83972 appears to prevent infection with UPEC strains in such patients despite the fact that this strain is unable to express the primary adhesins involved in UTI, viz. P and type 1 fimbriae. Here we investigated the growth characteristics of E. coli 83972 in human...... urine and show that it can outcompete a representative spectrum of UPEC strains for growth in urine. The unique ability of ABU E. coli 83972 to outcompete UPEC in urine was also demonstrated in a murine model of human UTI, confirming the selective advantage over UPEC in vivo. Comparison of global gene...

  20. Developments of borehole strain observation outside China

    Institute of Scientific and Technical Information of China (English)

    邱泽华; 石耀霖

    2004-01-01

    Borehole strain observation is playing an increasingly important role in the study on the crustal movements. It hasbeen used by many countries such as China, USA, Japan, Peru, Australia, South Africa, Iceland and Italy, in research fields of plate tectonics, earthquake, volcanic eruption, dam safety, oil field subsidence, mining collapse andso on. Borehole strainmeter has been improved rapidly and tends to get more and more components included inone probe. Based on observations by this kind of instruments, studies on seismic strain step, slow earthquake,earthquake precursor and volcanic eruption forecasting have made remarkable achievements. In the coming years,borehole strain observation is going to become one major geodetic means, together with GPS and InSAR.

  1. Influence of nuclear radiation on strain gauges

    Energy Technology Data Exchange (ETDEWEB)

    Andreae, G.; Niessen, G.

    The examination of safety of nuclear reactor components requires strain measurements on parts of constructions while operating and this means when influenced by nuclear radiation. As strain gauges are the most applied devices for strain measurement and very suitable in respect to their handling, the influence of nuclear radiation has been investigated for the first time more than 30 years ago in order to obtain information on the reliability of measuring results in such difficult environmental conditions. Since that time only some papers have been published dealing with the progress in this field of measuring technics. A generally valid statement however could not be obtained yet. The effect of 10 MeV electron irradiation on the specific resistivity has been studied.

  2. Influence of nuclear radiation on strain gauges

    International Nuclear Information System (INIS)

    The examination of safety of nuclear reactor components requires strain measurements on parts of constructions while operating and this means when influenced by nuclear radiation. As strain gauges are the most applied devices for strain measurement and very suitable in respect to their handling, the influence of nuclear radiation has been investigated for the first time more than 30 years ago in order to obtain information on the reliability of measuring results in such difficult environmental conditions. Since that time only some papers have been published dealing with the progress in this field of measuring technics. A generally valid statement however could not be obtained yet. The effect of 10 MeV electron irradiation on the specific resistivity has been studied. (orig./HP)

  3. Nuclear transplantation in different strains of zebrafish

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Single later blastula nuclei from AB strain of zebrafish (Danio rerio) were transplanted into enucleated unfertilized eggs of Long fin strain. Of 1119 cloning embryos, 14 reconstructed embryos developed into fry. DNA fingerprinting systems of the cloned fish were similar to those of the nuclear donor fish, but were distinctly different from those of the nuclear recipient fish. It confirmed that the genetic material originated from nuclear donor cell other than from nuclear recipient egg. The research suggested that the basic technique for nuclear transplantation performed with different strains of zebrafish has made a breakthrough. It should be helpful for the study of some important developmental problems such as gene function, the regulation of gene expression during animal development, the developmental potential of a nucleus and the interactions between the donor nucleus and the recipient cytoplasm, etc.

  4. Survival and activity of individual bioaugmentation strains

    DEFF Research Database (Denmark)

    Dueholm, Morten Simonsen; G. Marquesa, Irina; Karst, Søren Michael;

    2015-01-01

    Successful application of bioaugmentation for enhanced degradation of environmental pollutants is often limited by the lack of methods to monitor the survival and activity of individual bioaugmentation strains. However, recent advancements in sequencing technologies and molecular techniques now...... allow us to address these limitations. Here a complementing set of general applicable molecular methods are presented that provides detailed information on the performance of individual bioaugmentation strains under in situ conditions. The approach involves genome sequencing to establish highly specific...... qPCR and RT-qPCR tools for cell enumerations and expression of involved genes, stable isotope probing to follow growth on the target compounds and GFP-tagging to visualize the bioaugmentation strains directly in samples, all in combination with removal studies of the target compounds. The concept...

  5. Development of Industrial Yeast Platform Strains

    DEFF Research Database (Denmark)

    Bergdahl, Basti; Dato, Laura; Förster, Jochen

    2014-01-01

    frequently encounter high substrate concentrations, low pH, high temperatures and various inhibitory compounds originating either from the raw material used or from cellular metabolism. The aim of this research project is to develop robust platform strains of Saccharomyces cerevisiae based on industrial...... main tasks that are interconnected to reach the final goal (Fig. 1).It is highly multidisciplinary and involves several research fields. In this communication, we will present selected results from ongoing activities, such as the whole genomes equencing, intracellular metabolite profiling and tolerance...... screening of the 36 industrial and laboratory yeast strains. In addition, progress in the development of molecular biology methods for generating the new strains will be presented....

  6. High sensitivity knitted fabric strain sensors

    Science.gov (United States)

    Xie, Juan; Long, Hairu; Miao, Menghe

    2016-10-01

    Wearable sensors are increasingly used in smart garments for detecting and transferring vital signals and body posture, movement and respiration. Existing fabric strain sensors made from metallized yarns have low sensitivity, poor comfort and low durability to washing. Here we report a knitted fabric strain sensor made from a cotton/stainless steel (SS) fibre blended yarn which shows much higher sensitivity than sensors knitted from metallized yarns. The fabric feels softer than pure cotton textiles owing to the ultrafine stainless steel fibres and does not lose its electrical property after washing. The reason for the high sensitivity of the cotton/SS knitted fabric sensor was explored by comparing its sensing mechanism with the knitted fabric sensor made from metallized yarns. The results show that the cotton/SS yarn-to-yarn contact resistance is highly sensitive to strain applied to hooked yarn loops.

  7. Realization of a Strained Atomic Wire Superlattice.

    Science.gov (United States)

    Song, Inkyung; Goh, Jung Suk; Lee, Sung-Hoon; Jung, Sung Won; Shin, Jin Sung; Yamane, Hiroyuki; Kosugi, Nobuhiro; Yeom, Han Woong

    2015-11-24

    A superlattice of strained Au-Si atomic wires is successfully fabricated on a Si surface. Au atoms are known to incorporate into the stepped Si(111) surface to form a Au-Si atomic wire array with both one-dimensional (1D) metallic and antiferromagnetic atomic chains. At a reduced density of Au, we find a regular array of Au-Si wires in alternation with pristine Si nanoterraces. Pristine Si nanoterraces impose a strain on the neighboring Au-Si wires, which modifies both the band structure of metallic chains and the magnetic property of spin chains. This is an ultimate 1D version of a strained-layer superlattice of semiconductors, defining a direction toward the fine engineering of self-assembled atomic-scale wires. PMID:26446292

  8. Comparison of barley stripe mosaic virus strains.

    Science.gov (United States)

    Hafez, Elsayed E; Abdel Aleem, Engy E; Fattouh, Faiza A

    2008-01-01

    BSMV (barley stripe mosaic virus) particles were obtained in a pure state from infected host plant tissues of Hordeum vulgare. The three genomic parities (alpha, beta and gamma) were amplified by PCR using specific primers for each particle; each was cloned. Partial sequence of the alpha, beta and gamma segments was determined for the Egyptian isolate of barley stripe mosaic virus (BSMV AE1). Alignment of nucleotide sequences with that of other known strains of the virus, BSMV type strains (CV17, ND18 and China), and the generation of phylogenetic trees was performed. A low level of homology was detected comparing 467 bp of the a and 643 bp of the segments to that of the other strains, and thus BSMV alpha and beta segments were in separate clusters. However, 1154 bp of the gamma segments of BSMV AE1 showed a high level of homology especially to strain BSMV ND18, as they both formed a distinct cluster. Northern blotting of pure BSMV AE1 virus and H. vulgare-infected tissue were compared using an alpha ND18 specific probe. Western blotting using antibodies specific for the coat protein (CP) and the triple gene block 1 (TGB1) protein, which are both encoded by the beta ND18 segment, still indicated a high level of similarity between proteins produced by BSMV ND18 and AE1. We suggest that the BSMV AE1 isolate is a distinct strain of BSMV which reflects the genetic evolutionary divergence among BSMV strains and members of the Hordeivirus group. PMID:18533473

  9. Gate leakage mechanisms in strained Si devices

    Science.gov (United States)

    Yan, L.; Olsen, S. H.; Kanoun, M.; Agaiby, R.; O'Neill, A. G.

    2006-11-01

    This work investigates gate leakage mechanisms in advanced strained Si /SiGe metal-oxide-semiconductor field-effect transistor (MOSFET) devices. The impact of virtual substrate Ge content, epitaxial material quality, epitaxial layer structure, and device processing on gate oxide leakage characteristics are analyzed in detail. In state of the art MOSFETs, gate oxides are only a few nanometers thick. In order to minimize power consumption, leakage currents through the gate must be controlled. However, modifications to the energy band structure, Ge diffusion due to high temperature processing, and Si /SiGe material quality may all affect gate oxide leakage in strained Si devices. We show that at high oxide electric fields where gate leakage is dominated by Fowler-Nordheim tunneling, tensile strained Si MOSFETs exhibit lower leakage levels compared with bulk Si devices. This is a direct result of strain-induced splitting of the conduction band states. However, for device operating regimes at lower oxide electric fields Poole-Frenkel emissions contribute to strained Si gate leakage and increase with increasing virtual substrate Ge content. The emissions are shown to predominantly originate from surface roughness generating bulk oxide traps, opposed to Ge diffusion, and can be improved by introducing a high temperature anneal. Gate oxide interface trap density exhibits a dissimilar behavior and is highly sensitive to Ge atoms at the oxidizing surface, degrading with increasing thermal budget. Consequently advanced strained Si /SiGe devices are inadvertently subject to a potential tradeoff between power consumption (gate leakage current) and device reliability (gate oxide interface quality).

  10. Variability among Rhizobium Strains Originating from Nodules of Vicia faba.

    Science.gov (United States)

    van Berkum, P; Beyene, D; Vera, F T; Keyser, H H

    1995-07-01

    Rhizobium strains from nodules of Vicia faba were diverse in plasmid content and serology. Results of multilocus gel electrophoresis and restriction fragment length polymorphism indicated several deep chromosomal lineages among the strains. Linkage disequilibrium among the chromosomal types was detected and may have reflected variation of Rhizobium strains in the different geographical locations from which the strains originated. An investigation of pea strains with antibodies prepared against fava bean strains and restriction fragment length polymorphism analyses, targeting DNA regions coding for rRNA and nodulation, indicated that Rhizobium strains from V. faba nodules were distinguishable from those from Pisum sativum, V. villosa, and Trifolium spp. PMID:16535075

  11. Tensile Properties of TWIP Steel at High Strain Rate

    Institute of Scientific and Technical Information of China (English)

    XIONG Rong-gang; FU Ren-yu; SU Yu; LI Qian; WEI Xi-cheng; LI Lin

    2009-01-01

    Tensile tests of TWIP steels of two compositions are performed in the strain rate range of 10-5 -103 s-1.Results indicate that steel 1# does not exhibit TWIP effect but deformation-induced martensitic transformation appears only.There exists TWIP effect in steel 3#.Tensile properties at room temperature are sensitive to strain rate in the studied strain rate ranges.Analysis on the relationship between strain-hardening exponent and strain rates shows that strain-induced martensitic transformation and formation of twins during deformation have significant influence on their strain-hardening behavior.

  12. Digital Eye Strain Reduction Techniques: A Review

    Directory of Open Access Journals (Sweden)

    PREETHI J SEEGEHALLI

    2016-03-01

    Full Text Available Digital eye strain or computer vision syndrome (CVS is caused when we spend considerable amount of time in staring at digital screens of desktop computer, laptop, e-readers, tablets and mobile phones. This paper discusses the different the causes for visual fatigue and digital eye strain reduction techniques like usage of optical glass, flicker free screen, color filtering, fuzzy logic based brightness adaption technique, bias lighting screens, optimizing monitor’s color temperature and Auto brightness control of digital screen. The paper also discusses the good practices to reduce visual fatigue.

  13. Genome sequence of Haemophilus parasuis strain 29755

    OpenAIRE

    Mullins, Michael A.; Register, Karen B.; Bayles, Darrell O; Dyer, David W.; Joanna S Kuehn; Phillips, Gregory J.

    2011-01-01

    Haemophilus parasuis is a member of the family Pasteurellaceae and is the etiologic agent of Glässer’s disease in pigs, a systemic syndrome associated with only a subset of isolates. The genetic basis for virulence and systemic spread of particular H. parasuis isolates is currently unknown. Strain 29755 is an invasive isolate that has long been used in the study of Glässer’s disease. Accordingly, the genome sequence of strain 29755 is of considerable importance to investigators endeavoring to...

  14. Cells as strain-cued automata

    Science.gov (United States)

    Cox, Brian N.; Snead, Malcolm L.

    2016-02-01

    We argue in favor of representing living cells as automata and review demonstrations that autonomous cells can form patterns by responding to local variations in the strain fields that arise from their individual or collective motions. An autonomous cell's response to strain stimuli is assumed to be effected by internally-generated, internally-powered forces, which generally move the cell in directions other than those implied by external energy gradients. Evidence of cells acting as strain-cued automata have been inferred from patterns observed in nature and from experiments conducted in vitro. Simulations that mimic particular cases of pattern forming share the idealization that cells are assumed to pass information among themselves solely via mechanical boundary conditions, i.e., the tractions and displacements present at their membranes. This assumption opens three mechanisms for pattern formation in large cell populations: wavelike behavior, kinematic feedback in cell motility that can lead to sliding and rotational patterns, and directed migration during invasions. Wavelike behavior among ameloblast cells during amelogenesis (the formation of dental enamel) has been inferred from enamel microstructure, while strain waves in populations of epithelial cells have been observed in vitro. One hypothesized kinematic feedback mechanism, "enhanced shear motility", accounts successfully for the spontaneous formation of layered patterns during amelogenesis in the mouse incisor. Directed migration is exemplified by a theory of invader cells that sense and respond to the strains they themselves create in the host population as they invade it: analysis shows that the strain fields contain positional information that could aid the formation of cell network structures, stabilizing the slender geometry of branches and helping govern the frequency of branch bifurcation and branch coalescence (the formation of closed networks). In simulations of pattern formation in

  15. Development of inkjet printed strain sensors

    International Nuclear Information System (INIS)

    Strain sensors with different architectures, such as single sensors, sensor arrays and a sensor matrix have been developed by inkjet printing technology. Sensors with gauge factors up to 2.48, dimensions of 1.5 mm × 1.8 mm and interdigitated structures with a distance of 30 μm between the finger lines have been achieved based on PeDOT (poly(3,4-ethylenedioxythiophene) and conductive ink. Strain gauges based on silver ink have also been achieved with a gauge factor of 0.35. Performance tests including 1000 mechanical cycles have been successfully carried out for the development of smart prosthesis applications. (paper)

  16. Tensile strain mapping in flat germanium membranes

    Energy Technology Data Exchange (ETDEWEB)

    Rhead, S. D., E-mail: S.Rhead@warwick.ac.uk; Halpin, J. E.; Myronov, M.; Patchett, D. H.; Allred, P. S.; Wilson, N. R.; Leadley, D. R. [Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom); Shah, V. A. [Department of Physics, University of Warwick, Coventry, CV4 7AL (United Kingdom); Department of Engineering, University of Warwick, Coventry, CV4 7AL (United Kingdom); Kachkanov, V.; Dolbnya, I. P. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE (United Kingdom); Reparaz, J. S. [ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona) (Spain); Sotomayor Torres, C. M. [ICN2 - Institut Catala de Nanociencia i Nanotecnologia, Campus UAB, 08193 Bellaterra (Barcelona) (Spain)

    2014-04-28

    Scanning X-ray micro-diffraction has been used as a non-destructive probe of the local crystalline quality of a thin suspended germanium (Ge) membrane. A series of reciprocal space maps were obtained with ∼4 μm spatial resolution, from which detailed information on the strain distribution, thickness, and crystalline tilt of the membrane was obtained. We are able to detect a systematic strain variation across the membranes, but show that this is negligible in the context of using the membranes as platforms for further growth. In addition, we show evidence that the interface and surface quality is improved by suspending the Ge.

  17. Tensile strain mapping in flat germanium membranes

    International Nuclear Information System (INIS)

    Scanning X-ray micro-diffraction has been used as a non-destructive probe of the local crystalline quality of a thin suspended germanium (Ge) membrane. A series of reciprocal space maps were obtained with ∼4 μm spatial resolution, from which detailed information on the strain distribution, thickness, and crystalline tilt of the membrane was obtained. We are able to detect a systematic strain variation across the membranes, but show that this is negligible in the context of using the membranes as platforms for further growth. In addition, we show evidence that the interface and surface quality is improved by suspending the Ge

  18. Development of inkjet printed strain sensors

    Science.gov (United States)

    Correia, V.; Caparros, C.; Casellas, C.; Francesch, L.; Rocha, J. G.; Lanceros-Mendez, S.

    2013-10-01

    Strain sensors with different architectures, such as single sensors, sensor arrays and a sensor matrix have been developed by inkjet printing technology. Sensors with gauge factors up to 2.48, dimensions of 1.5 mm × 1.8 mm and interdigitated structures with a distance of 30 μm between the finger lines have been achieved based on PeDOT (poly(3,4-ethylenedioxythiophene) and conductive ink. Strain gauges based on silver ink have also been achieved with a gauge factor of 0.35. Performance tests including 1000 mechanical cycles have been successfully carried out for the development of smart prosthesis applications.

  19. Forty mouse strain survey of body composition

    OpenAIRE

    Danielle R Reed; Bachmanov, Alexander A.; Tordoff, Michael G.

    2007-01-01

    We measured body weight and composition of ~10 male and ~10 female mice from 40 inbred strains. Body composition was assessed in ~16-wk old mice that had been individually housed and fed a high-carbohydrate, low-fat diet (AIN-76A) for the previous 8 wk. Carcass lean and fat weights were assessed using a PIXIMus II DEXA and confirmed by fat extraction assay. There was a nearly continuous range of body weights, from a strain mean±SE of 11.4±0.2 g (MSM/MsJ) to 39.3±1.8 g (NON/LtJ). The percentag...

  20. 秦皇岛海域"褐潮"海水对卤虫、轮虫存活和摄食的影响研究%Effect of "Brown Tide" onsurvival and ingestion of Artemia salina and Brachionus plicatilis in Qinhuangdao

    Institute of Scientific and Technical Information of China (English)

    公晗; 孔凡洲; 王云峰; 颜天; 周名江

    2015-01-01

    为评价秦皇岛褐潮现场海水的毒性, 作者利用HPLC技术及CHEMTAX, 分析了2013年7月2日采自秦皇岛褐潮高峰期微型及微微型浮游植物的色素组成及群落结构;测定了卤虫(Artemia salina)、轮虫(Brachionus plicatilis)存活率和摄食量.研究表明,褐潮海水微型及微微型浮游植物中,海金藻(Pelagophyceae)占主要优势,其生物量占总生物量的72.6%.褐潮海水抑制卤虫存活,卤虫48 h存活率降至77%;对轮虫24 h存活没有显著效应.此外,褐潮海水抑制卤虫、轮虫的摄食,卤虫、轮虫8 h内摄食量分别由(5.5±0.4)ng/个降至(2.4±0.4)ng/个、由(1.5±0.2)ng/个下降至(0.9±0.1)ng/个.该结果与美国的3株褐潮藻的毒性进行了比较.CCMP 1507对卤虫存活有显著抑制作用,其他两株没有显著效应; 3株褐潮藻对轮虫24 h存活都没有显著影响.暴露于3株褐潮藻中,卤虫的摄食量均显著较低;其中CCMP 1507在混合饵料中还抑制卤虫、轮虫对其他藻的摄食.对CCMP 1507各组分分析发现,该藻的毒性主要来源于藻细胞.结合现场试验与室内试验结果分析表明, 秦皇岛褐潮对卤虫、轮虫有一定的毒性,其毒性与CCMP 1507的毒性相当.%To studythe toxicity of the "Brown tide" in Qinhuangdao, the pigment profile and phytoplankton groups of the nano-sized and pico-sized phytoplankton samples collected from the "Brown tide" blooming sea area in Qinhuangdao on July 2rd, 2013 were analyzed using HPLC and CHEMTAX, and the survival and ingestion of Ar-temia salina and Brachionus plicatiliswere tested. It was found that pelagophytes played a predominant role, con-stituting 72.6% of the total phytoplankton biomass. The survival of A. salina decreased to 77% during 48 h expo-sure, while that of rotifer was not affected during 24 h exposure. Additionally, the ingestion of A. Salinaand rotifer in 8 hours was inhibited, reduced from (5.5±0.4)ng/ind to (2.4±0.4) ng/ind, and from (1.5±0.2) ng

  1. Serological Strains of Tobacco Ringspot Virus Transmitted by Xiphinema americanum.

    Science.gov (United States)

    Rush, M C

    1970-07-01

    Five serological strains of tobacco ringspot virus isolated from naturally infected tobacco in North Carolina, and a strain isolated from watermelon in the Rio Grande Valley of Texas were transmitted from cucumber to cucumber by mass-screened and handpicked Xiphinerna americanum from North Carolina. The Eucharis mottle strain from Peru was not transmitted, indicating that a specific strain-vector relationship may exist between the geographically isolated strains from North and South America.

  2. Reliability of PEDOT-PSS Strain Gauge on foam structure

    OpenAIRE

    Chang, Cheng-Ling; Fix, Kayla; Wang, Wei-Chih

    2010-01-01

    Reliability is one important issue in using PEDOT: PSS as a strain gauge for large strain measurements. In our research, PEDOT: PSS strain gauge is fabricated on the polyurethane and porous substrate, which enhances the mechanical property when large strain and cyclic loads are applied to it. Our result shows that with the polyurethane as the substrate adhesion layer, the strain of PEDOT: PSS can go up to 17.7% and stabilize without reference resistance drifting.

  3. A Wireless Strain Sensor Network for Structural Health Monitoring

    OpenAIRE

    Chengyin Liu; Jun Teng; Ning Wu

    2015-01-01

    Structural strain under external environmental loads is one of the main monitoring parameters in structural health monitoring or dynamic tests. This paper presents a wireless strain sensor network (WSSN) design for monitoring structural dynamic strain field. A precision strain sensor board is developed and integrated with the IRIS mote hardware/software platform for multichannel strain gauge signal conditioning and wireless monitoring. Measurement results confirm the sensor’s functionality re...

  4. Two-Dimensional Laser-Speckle Surface-Strain Gauge

    Science.gov (United States)

    Barranger, John P.; Lant, Christian

    1992-01-01

    Extension of Yamaguchi's laser-speckle surface-strain-gauge method yields data on two-dimensional surface strains in times as short as fractions of second. Laser beams probe rough spot on surface of specimen before and after processing. Changes in speckle pattern of laser light reflected from spot indicative of changes in surface strains during processing. Used to monitor strains and changes in strains induced by hot-forming and subsequent cooling of steel.

  5. Design of Monolithic Integrator for Strain-to-Frequency Converter

    OpenAIRE

    Tuan Mohd. Khairi Tuan Mat; Chew Sue Ping; Akram Abdul Azid

    2012-01-01

    Strain-to-Frequency converter (SFC) is a one of the analog conditioner tools that converts any strain signal to the frequency signal. The basic concept of SFC is by detecting any changing of strains, then converting the strain to the voltage signal and converting the voltage signal to the frequency signal. This tool consists of 3 main  components which are strain gauge, differential integrator and comparator. This paper presents the designing and analysis of monolithic integrator that to be u...

  6. Variability among Rhizobium Strains Originating from Nodules of Vicia faba

    OpenAIRE

    van Berkum, P; Beyene, D; Vera, F. T.; Keyser, H. H.

    1995-01-01

    Rhizobium strains from nodules of Vicia faba were diverse in plasmid content and serology. Results of multilocus gel electrophoresis and restriction fragment length polymorphism indicated several deep chromosomal lineages among the strains. Linkage disequilibrium among the chromosomal types was detected and may have reflected variation of Rhizobium strains in the different geographical locations from which the strains originated. An investigation of pea strains with antibodies prepared agains...

  7. GENDER, CUMULATIVE STRAIN AND DEVIANT BEHAVIOR IN TURKEY

    OpenAIRE

    Özbay, Özden

    2013-01-01

     ABSTRACTThe purpose of this study is to explore whether General Strain Theory played a similar role for male and female deviant acts among the youths in Turkey. Data was derived from 974 students at a Turkish public university. The findings indicated that cumulative strain, anger, and criminal and non-criminal copings played similar roles for both males and females. The results questioned General Strain Theory’s gender difference thesis.Keywords: General strain theory, cumulative strain, gen...

  8. Entire deformational characteristics and strain localization of jointed rock specimen in plane strain compression

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Shear band (SB),axial, lateral and volumetric strains as well as Poisson's ratio of anisotropic jointed rock specimen (JRS) were modeled by Fast Lagrangian Analysis of Continua (FLAC). Failure criterion of rock was a composited Mohr-Coulomb criterion with tension cut-off. An inclined joint was treated as square elements of ideal plastic material beyond the peak strength. Several FISH functions were written to automatically find the addresses of elements in the joint and to calculate the entire deformational characteristics of plane strain JRS. The results show that for moderate joint inclination (JI), strain is only concentrated into the joint governing the behavior of JRS,leading to ideal plastic responses in axial and lateral directions. For higher JI, the post-peak stress-axial and lateral strain curves become steeper as JI increases owing to the increase of new SB's length. Lateral expansion and precursor to the unstable failure are the most apparent, resulting in the highest Poisson's ratio and even negative volumetric strain. For lower JI, the entire post-peak deformational characteristics are independent of JI. The lowest lateral expansion occurs, leading to the lowest Poisson's ratio and positive volumetric strain all along. The present prediction on anisotropic strength in plane strain compression qualitatively agrees with the results in triaxial tests of rocks.The JI calculated by Jaeger's formula overestimates that related to the minimum strength. Advantages of the present numerical model over the Jaeger's model are pointed out.

  9. Probiotic Potential of Lactobacillus Strains with Antimicrobial Activity against Some Human Pathogenic Strains

    Directory of Open Access Journals (Sweden)

    Parisa Shokryazdan

    2014-01-01

    Full Text Available The objective of this study was to isolate, identify, and characterize some lactic acid bacterial strains from human milk, infant feces, and fermented grapes and dates, as potential probiotics with antimicrobial activity against some human pathogenic strains. One hundred and forty bacterial strains were isolated and, after initial identification and a preliminary screening for acid and bile tolerance, nine of the best isolates were selected and further identified using 16 S rRNA gene sequences. The nine selected isolates were then characterized in vitro for their probiotic characteristics and their antimicrobial activities against some human pathogens. Results showed that all nine isolates belonged to the genus Lactobacillus. They were able to tolerate pH 3 for 3 h, 0.3% bile salts for 4 h, and 1.9 mg/mL pancreatic enzymes for 3 h. They exhibited good ability to attach to intestinal epithelial cells and were not resistant to the tested antibiotics. They also showed good antimicrobial activities against the tested pathogenic strains of humans, and most of them exhibited stronger antimicrobial activity than the reference strain L. casei Shirota. Thus, the nine Lactobacillus strains could be considered as potential antimicrobial probiotic strains against human pathogens and should be further studied for their human health benefits.

  10. On Boreholes and PBO Borehole Strain

    Science.gov (United States)

    Gladwin, M. T.; Mee, M. W.

    2003-12-01

    Borehole tensor strainmeters (GTSM) installed in Australia and California have established a baseline of data spanning more than twenty years. The current baseline of data allows characterisation of a moderate number of instruments in a range of very different environments in a way which defines reasonable performance expectations for the upcoming PBO deployments. A generic understanding of effects which result from the process of installation of the instrument in a stressed rock mass emerges. This indicates that, provided due allowance is made for experimentally determined borehole recovery effects, the contribution of borehole strain meters more than adequately fills the observational gap between high stability/long term geodetic measurements of strain and strain rates and high resolution/high frequency seismic observations of earth deformation processes. The various strain relief processes associated with the installation procedures and borehole recovery effects associated with pre-existing stress fields will be documented. Procedures for calibration of the total borehole inclusion and for progressive removal of effects due to rock anisotropy and visco-elastic creep of the grout and rock close to the borehole from far field tectonic effects will be defined and illustrated with examples. Observed deviations from these processes will be shown to be small and consistent with otherwise observed or implied fault motions. Full details of these borehole induced processes are, however, difficult to determine in the early years following installation, particularly if there is significant tectonic activity at the time. Once quantified for each site, the effects can be robustly removed from data streams.

  11. High strain rate behaviour of polypropylene microfoams

    Science.gov (United States)

    Gómez-del Río, T.; Garrido, M. A.; Rodríguez, J.; Arencón, D.; Martínez, A. B.

    2012-08-01

    Microcellular materials such as polypropylene foams are often used in protective applications and passive safety for packaging (electronic components, aeronautical structures, food, etc.) or personal safety (helmets, knee-pads, etc.). In such applications the foams which are used are often designed to absorb the maximum energy and are generally subjected to severe loadings involving high strain rates. The manufacture process to obtain polymeric microcellular foams is based on the polymer saturation with a supercritical gas, at high temperature and pressure. This method presents several advantages over the conventional injection moulding techniques which make it industrially feasible. However, the effect of processing conditions such as blowing agent, concentration and microfoaming time and/or temperature on the microstructure of the resulting microcellular polymer (density, cell size and geometry) is not yet set up. The compressive mechanical behaviour of several microcellular polypropylene foams has been investigated over a wide range of strain rates (0.001 to 3000 s-1) in order to show the effects of the processing parameters and strain rate on the mechanical properties. High strain rate tests were performed using a Split Hopkinson Pressure Bar apparatus (SHPB). Polypropylene and polyethylene-ethylene block copolymer foams of various densities were considered.

  12. Division Heads and Role Strain Perception.

    Science.gov (United States)

    Simpson, William M.

    1984-01-01

    Reports on a study of the extent to which ambiguous and conflicting circumstances contribute to role strain perceptions among community college division heads. Clarifies how working conditions and personal attributes affect job expectations. Finds experience, age, outlook, and job satisfaction to be strong influential factors. (DMM)

  13. A novel limiting strain energy strength theory

    Institute of Scientific and Technical Information of China (English)

    LIU Guang-lian

    2009-01-01

    With applied dislocation theory,the effects of shear and normal stresses on the slide and climb motions at the same section of a crystal were analyzed.And,based on the synergetic effect of both normal and shear strain specific energies,the concept of the total equivalent strain specific energy (TESSE) at an oblique section and a new strength theory named as limiting strain energy strength theory (LSEST) were proposed.As for isotropic materials,the plastic yielding or brittle fracture of under uniaxial stress state would occur when the maximum TESSE reached the strain specific energy,also the expressions on the equivalent stresses and a function of failure of the LSEST under different principal stress states were obtained.Relationship formulas among the tensile,compressive and shear yield strengths for plastic metals were derived.These theoretical predictions,according to the LSEST,were consistent very well with experiment results of tensile,compressive and torsion tests of three plastic metals and other experiment results from open literatures.This novel LSEST might also help for strength calculation of other materials.

  14. Thermal Strain Analysis of Optic Fiber Sensors

    Directory of Open Access Journals (Sweden)

    Chih-Ying Huang

    2013-01-01

    Full Text Available An optical fiber sensor surface bonded onto a host structure and subjected to a temperature change is analytically studied in this work. The analysis is developed in order to assess the thermal behavior of an optical fiber sensor designed for measuring the strain in the host structure. For a surface bonded optical fiber sensor, the measuring sensitivity is strongly dependent on the bonding characteristics which include the protective coating, adhesive layer and the bonding length. Thermal stresses can be generated due to a mismatch of thermal expansion coefficients between the optical fiber and host structure. The optical fiber thermal strain induced by the host structure is transferred via the adhesive layer and protective coating. In this investigation, an analytical expression of the thermal strain and stress in the optical fiber is presented. The theoretical predictions are validated using the finite element method. Numerical results show that the thermal strain and stress are linearly dependent on the difference in thermal expansion coefficients between the optical fiber and host structure and independent of the thermal expansion coefficients of the adhesive and coating.

  15. High strain rate behaviour of polypropylene microfoams

    Directory of Open Access Journals (Sweden)

    Martínez A.B.

    2012-08-01

    Full Text Available Microcellular materials such as polypropylene foams are often used in protective applications and passive safety for packaging (electronic components, aeronautical structures, food, etc. or personal safety (helmets, knee-pads, etc.. In such applications the foams which are used are often designed to absorb the maximum energy and are generally subjected to severe loadings involving high strain rates. The manufacture process to obtain polymeric microcellular foams is based on the polymer saturation with a supercritical gas, at high temperature and pressure. This method presents several advantages over the conventional injection moulding techniques which make it industrially feasible. However, the effect of processing conditions such as blowing agent, concentration and microfoaming time and/or temperature on the microstructure of the resulting microcellular polymer (density, cell size and geometry is not yet set up. The compressive mechanical behaviour of several microcellular polypropylene foams has been investigated over a wide range of strain rates (0.001 to 3000 s−1 in order to show the effects of the processing parameters and strain rate on the mechanical properties. High strain rate tests were performed using a Split Hopkinson Pressure Bar apparatus (SHPB. Polypropylene and polyethylene-ethylene block copolymer foams of various densities were considered.

  16. Strain intermittency in shape-memory alloys

    Science.gov (United States)

    Balandraud, Xavier; Barrera, Noemi; Biscari, Paolo; Grédiac, Michel; Zanzotto, Giovanni

    2015-05-01

    We study experimentally the intermittent progress of the mechanically induced martensitic transformation in a Cu-Al-Be single crystal through a full-field measurement technique: the grid method. We utilize an in-house, specially designed gravity-based device, wherein a system controlled by water pumps applies a perfectly monotonic uniaxial load through very small force increments. The sample exhibits hysteretic superelastic behavior during the forward and reverse cubic-monoclinic transformation, produced by the evolution of the strain field of the phase microstructures. The in-plane linear strain components are measured on the sample surface during the loading cycle, and we characterize the strain intermittency in a number of ways, showing the emergence of power-law behavior for the strain avalanching over almost six decades of magnitude. We also describe the nonstationarity and the asymmetry observed in the forward versus reverse transformation. The present experimental approach, which allows for the monitoring of the reversible martensitic transformation both locally and globally in the crystal, proves useful and enhances our capabilities in the analysis and possible control of transition-related phenomena in shape-memory alloys.

  17. Charge and Strain Control of Interface Magnetism

    Science.gov (United States)

    Fitzsimmons, M. R.; Dumesnil, K.; Jaouen, N.; Maroutian, T.; Agnus, G.; Tonnerre, J.-M.; Kirby, B.; Fohtung, E.; Holladay, B.; Fullerton, E. E.; Shpyrko, O.; Sinha, S. K.; Wang, Q.; Chen, A.; Jia, Q. X.

    2015-03-01

    We studied the influence of an electric field applied to an La0.67Sr0.33MnO3 (LSMO) layer in a LSMO/Pb(Zr0.2Ti0.8) O3 (PZT)/Nb-doped SrTiO3 (STO) heterostructure by measuring its magnetization depth profile using resonant x-ray magnetic reflectivity. The saturation magnetization of the ferromagnetically-ordered LSMO was not affected by the direction of the polarization of the PZT. However, the ferromagnetic thickness and magnetization of the LSMO film at remanence were reduced for hole-charge accumulation at the LSMO/PZT interface. To understand the independent roles of strain and hole-doping, we performed neutron scattering experiments of La0.8Sr0.2MnO3 films grown on Nb-doped STO in which bending strain (via 4-point bending jig) or electric field (via parallel plate capacitor) was applied to the films. We observed that bending strain affects the saturation magnetization of the LSMO film, whereas electric field affects the remanent magnetization of the film. These observations suggest strain may be a more effective means to control magnetism than charge. This work has benefited from use of CINT(LANL), NIST Center for Neutron Research and the Synchrotron SOLEIL and funding from LANL/LDRD program, DOE-BES (UCSD) and DOD (NMSU).

  18. Prediction of swelling rocks strain in tunneling

    Science.gov (United States)

    Parsapour, D.; Fahimifar, A.

    2016-05-01

    Swelling deformations leading to convergence of tunnels may result in significant difficulties during the construction, in particular for long term use of tunnels. By extracting an experimental based explicit analytical solution for formulating swelling strains as a function of time and stress, swelling strains are predicted from the beginning of excavation and during the service life of tunnel. Results obtained from the analytical model show a proper agreement with experimental results. This closed-form solution has been implemented within a numerical program using the finite element method for predicting time-dependent swelling strain around tunnels. Evaluating effects of swelling parameters on time-dependent strains and tunnel shape on swelling behavior around the tunnel according to this analytical solution is considered. The ground-support interaction and consequent swelling effect on the induced forces in tunnel lining is considered too. Effect of delay in lining installation on swelling pressure which acting on the lining and its structural integrity, is also evaluated. A MATLAB code of " SRAP" is prepared and applied to calculate all swelling analysis around tunnels based on analytical solution.

  19. Thermal strain analysis of optic fiber sensors.

    Science.gov (United States)

    Her, Shiuh-Chuan; Huang, Chih-Ying

    2013-01-31

    An optical fiber sensor surface bonded onto a host structure and subjected to a temperature change is analytically studied in this work. The analysis is developed in order to assess the thermal behavior of an optical fiber sensor designed for measuring the strain in the host structure. For a surface bonded optical fiber sensor, the measuring sensitivity is strongly dependent on the bonding characteristics which include the protective coating, adhesive layer and the bonding length. Thermal stresses can be generated due to a mismatch of thermal expansion coefficients between the optical fiber and host structure. The optical fiber thermal strain induced by the host structure is transferred via the adhesive layer and protective coating. In this investigation, an analytical expression of the thermal strain and stress in the optical fiber is presented. The theoretical predictions are validated using the finite element method. Numerical results show that the thermal strain and stress are linearly dependent on the difference in thermal expansion coefficients between the optical fiber and host structure and independent of the thermal expansion coefficients of the adhesive and coating.

  20. Influence of nuclear radiation on strain gauges

    International Nuclear Information System (INIS)

    The influence of nuclear radiation on strain gauges is a superposition of a primary effect (generation of lattice defects resulting in an increase of resistance), a secondary effect (caused by radiation induced diffusion, which - depending on the material and its prior thermodynamic state - leads to a decrease or increase of resistance) and an after-effect (change of resistance after irradiation or between irradiations). The consequences of these effects depend on different parameters with mudual dependencies. Conclusion: Single strain gauges (quarter bridges) should not be used under nuclear radiation; the multitouch of - usually unknown - influence parameters makes a general prediction of the behaviour under radiation practically impossible. Particularly, it is impossible to apply methods such as choice of special materials or pretreatment procedures in order to get strain gauges for high radiation rates. Strain gauges in half-bridge configuration give - under optimum conditions a small difference of two large interfering quantities, which can hardly be estimated. Thus a prognosis of the performance under radiation remains doubtful. With 26 figs., 1 tab

  1. Revisiting the gauge fields of strained graphene

    Science.gov (United States)

    Iorio, Alfredo; Pais, Pablo

    2015-12-01

    We show that when graphene is only subject to strain, the spin connection gauge field that arises plays no measurable role, but when intrinsic curvature is present and strain is small, spin connection dictates most of the physics. We do so by showing that the Weyl field associated with strain is a pure gauge field and no constraint on the (2 +1 )-dimensional spacetime appears. On the other hand, for constant intrinsic curvature that also gives a pure gauge Weyl field, we find a classical manifestation of a quantum Weyl anomaly, descending from a constrained spacetime. We are in the position to do this because we find the equations that the conformal factor in (2 +1 ) dimensions has to satisfy, which is a nontrivial generalization to (2 +1 ) dimensions of the classic Liouville equation of the differential geometry of surfaces. Finally, we comment on the peculiarities of the only gauge field that can describe strain, the well-known pseudogauge field A1˜u11-u22 and A2˜u12 , and conclude by offering some scenarios in fundamental physics that this peculiar field could help to realize.

  2. Aligned carbon nanotube sheet piezoresistive strain sensors

    Science.gov (United States)

    Li, Ang; Bogdanovich, Alexander E.; Bradford, Philip D.

    2015-09-01

    Carbon nanotubes (CNTs) have a unique set of properties that may be useful in the production of next generation structural health monitoring composites. This research introduces a novel CNT based material system for strain and damage sensing applications. An aligned sheet of interconnected CNTs was drawn from a chemical vapor deposition grown CNT array and then bonded to the surface of glass fiber/epoxy composite coupons. Various types of mechanical tests were conducted, accompanied by real-time electrical data acquisition, in order to evaluate the electro-mechanical behavior of the developed sensing material. Specimens were loaded in the longitudinal and transverse CNT sheet orientations to investigate the anisotropy of the piezoresistive effect. The CNT sheets exhibited good sensing stability, linearity, sensitivity and repeatability within a practical strain range; which are crucial sensor features for health monitoring. It was also demonstrated that the CNT orientation in the sheet had a dramatic effect on the sensitivity, thus validating the usefulness of this sensing material for directional strain/damage monitoring. Finally, pre-straining of the CNT sheet sensors was conducted to further enhance the linearity of electro-mechanical response and long-term stability of the sensors during cyclic loading.

  3. Storage features of Lactobacillus Brevis strain 9

    Directory of Open Access Journals (Sweden)

    Utemurat Sagyndykov

    2013-03-01

    Full Text Available Current article presents the results of the research conducted on storing lactic bacteria. On the basis of results of experiments on liophilization of the culture of lactic bacteria Lactobacillus brevis strain №9, it has been concluded that the optimum way of storing the given culture is the method of liophilic drying with the vacuum soldering.

  4. Photonic skin for pressure and strain sensing

    Science.gov (United States)

    Chen, Xianfeng; Zhang, C.; van Hoe, B.; Webb, D. J.; Kalli, K.; van Steenberge, G.; Peng, G.-D.

    2010-04-01

    In this paper, we report on the strain and pressure testing of highly flexible skins embedded with Bragg grating sensors recorded in either silica or polymer optical fibre. The photonic skins, with a size of 10cm x 10cm and thickness of 1mm, were fabricated by embedding the polymer fibre or silica fibre containing Bragg gratings in Sylgard 184 from Dow Corning. Pressure sensing was studied using a cylindrical metal post placed on an array of points across the skin. The polymer fibre grating exhibits approximately 10 times the pressure sensitivity of the silica fibre and responds to the post even when it is placed a few centimetres away from the sensing fibre. Although the intrinsic strain sensitivities of gratings in the two fibre types are very similar, when embedded in the skin the polymer grating displayed a strain sensitivity approximately 45 times greater than the silica device, which also suffered from considerable hysteresis. The polymer grating displayed a near linear response over wavelength shifts of 9nm for 1% strain. The difference in behaviour we attribute to the much greater Young's modulus of the silica fibre (70 GPa) compared to the polymer fibre (3 GPa).

  5. Global Strain in Severe Aortic Valve Stenosis

    DEFF Research Database (Denmark)

    Dahl, Jordi S; Videbæk, Lars; Poulsen, Mikael K;

    2012-01-01

    BACKGROUND: -Global longitudinal systolic strain (GLS) is often reduced in aortic stenosis despite normal ejection fraction. The importance of reduced preoperative GLS on long-term outcome after aortic valve replacement (AVR) is unknown. METHODS AND RESULTS: -A total of 125 patients with severe...

  6. Measuring physical strain during ambulation with accelerometry

    NARCIS (Netherlands)

    Bussmann, J B; Hartgerink, I; van der Woude, L H; Stam, H J

    2000-01-01

    PURPOSE: To study the feasibility of ambulatory accelerometry in the evaluation of physical strain in walking at different speeds and different levels of economy. METHODS: Twelve able-bodied subjects performed a walking test on a treadmill with increasing walking speed. After a 6-wk period, these me

  7. High strain-rate magnetoelasticity in Galfenol

    Science.gov (United States)

    Domann, J. P.; Loeffler, C. M.; Martin, B. E.; Carman, G. P.

    2015-09-01

    This paper presents the experimental measurements of a highly magnetoelastic material (Galfenol) under impact loading. A Split-Hopkinson Pressure Bar was used to generate compressive stress up to 275 MPa at strain rates of either 20/s or 33/s while measuring the stress-strain response and change in magnetic flux density due to magnetoelastic coupling. The average Young's modulus (44.85 GPa) was invariant to strain rate, with instantaneous stiffness ranging from 25 to 55 GPa. A lumped parameters model simulated the measured pickup coil voltages in response to an applied stress pulse. Fitting the model to the experimental data provided the average piezomagnetic coefficient and relative permeability as functions of field strength. The model suggests magnetoelastic coupling is primarily insensitive to strain rates as high as 33/s. Additionally, the lumped parameters model was used to investigate magnetoelastic transducers as potential pulsed power sources. Results show that Galfenol can generate large quantities of instantaneous power (80 MW/m3 ), comparable to explosively driven ferromagnetic pulse generators (500 MW/m3 ). However, this process is much more efficient and can be cyclically carried out in the linear elastic range of the material, in stark contrast with explosively driven pulsed power generators.

  8. Network of flexible capacitive strain gauges for the reconstruction of surface strain

    International Nuclear Information System (INIS)

    Monitoring of surface strain on mesosurfaces is a difficult task, often impeded by the lack of scalability of conventional sensing systems. A solution is to deploy large networks of flexible strain gauges, a type of large area electronics. The authors have recently proposed a soft elastomeric capacitor (SEC) as an economical skin-type solution for large-scale deployment onto mesosurfaces. The sensing principle is based on a measurable change in the sensor’s capacitance upon strain. In this paper, we study the performance of the sensor at reconstructing surface strain map and deflection shapes. A particular feature of the sensor is that it measures surface strain additively, because it is not utilized within a Wheatstone bridge configuration. An algorithm is proposed to decompose the additive in-plane strain measurements from the SEC into principal components. The algorithm consists of assuming a polynomial shape function, and deriving the strain based on Kirchhoff plate theory. A least-squares estimator (LSE) is used to minimize the error between the assumed model and the SEC signals after the enforcement of boundary conditions. Numerical simulations are conducted on a symmetric rectangular cantilever thin plate under symmetric and asymmetric static loads to demonstrate the accuracy and real-time applicability of the algorithm. The performance of the algorithm is further examined on an asymmetric cantilever laminated thin plate constituted with orthotropic materials mimicking a wind turbine blade, and subjected to a non-stationary wind load. Results from simulations show good performance of the algorithm at reconstructing the surface strain maps for both in-plane principal strain components, and that it can be applied in real time. However, its performance can be improved by strengthening assumptions on boundary conditions. The algorithm exhibits robustness in performance with respect to load and noise in signals, except when most of the sensors’ signals are

  9. Network of flexible capacitive strain gauges for the reconstruction of surface strain

    Science.gov (United States)

    Wu, Jingzhe; Song, Chunhui; Saleem, Hussam S.; Downey, Austin; Laflamme, Simon

    2015-05-01

    Monitoring of surface strain on mesosurfaces is a difficult task, often impeded by the lack of scalability of conventional sensing systems. A solution is to deploy large networks of flexible strain gauges, a type of large area electronics. The authors have recently proposed a soft elastomeric capacitor (SEC) as an economical skin-type solution for large-scale deployment onto mesosurfaces. The sensing principle is based on a measurable change in the sensor’s capacitance upon strain. In this paper, we study the performance of the sensor at reconstructing surface strain map and deflection shapes. A particular feature of the sensor is that it measures surface strain additively, because it is not utilized within a Wheatstone bridge configuration. An algorithm is proposed to decompose the additive in-plane strain measurements from the SEC into principal components. The algorithm consists of assuming a polynomial shape function, and deriving the strain based on Kirchhoff plate theory. A least-squares estimator (LSE) is used to minimize the error between the assumed model and the SEC signals after the enforcement of boundary conditions. Numerical simulations are conducted on a symmetric rectangular cantilever thin plate under symmetric and asymmetric static loads to demonstrate the accuracy and real-time applicability of the algorithm. The performance of the algorithm is further examined on an asymmetric cantilever laminated thin plate constituted with orthotropic materials mimicking a wind turbine blade, and subjected to a non-stationary wind load. Results from simulations show good performance of the algorithm at reconstructing the surface strain maps for both in-plane principal strain components, and that it can be applied in real time. However, its performance can be improved by strengthening assumptions on boundary conditions. The algorithm exhibits robustness in performance with respect to load and noise in signals, except when most of the sensors’ signals are

  10. Recent advances in echocardiography: strain and strain rate imaging [version 1; referees: 3 approved

    Directory of Open Access Journals (Sweden)

    Oana Mirea

    2016-04-01

    Full Text Available Deformation imaging by echocardiography is a well-established research tool which has been gaining interest from clinical cardiologists since the introduction of speckle tracking. Post-processing of echo images to analyze deformation has become readily available at the fingertips of the user. New parameters such as global longitudinal strain have been shown to provide added diagnostic value, and ongoing efforts of the imaging societies and industry aimed at harmonizing methods will improve the technique further. This review focuses on recent advances in the field of echocardiographic strain and strain rate imaging, and provides an overview on its current and potential future clinical applications.

  11. Strain rate effects for spallation of concrete

    Directory of Open Access Journals (Sweden)

    Häussler-Combe Ulrich

    2015-01-01

    Full Text Available Appropriate triaxial constitutive laws are the key for a realistic simulation of high speed dynamics of concrete. The strain rate effect is still an open issue within this context. In particular the question whether it is a material property – which can be covered by rate dependent stress strain relations – or mainly an effect of inertia is still under discussion. Experimental and theoretical investigations of spallation of concrete specimen in a Hopkinson Bar setup may bring some evidence into this question. For this purpose the paper describes the VERD model, a newly developed constitutive law for concrete based on a damage approach with included strain rate effects [1]. In contrast to other approaches the dynamic strength increase is not directly coupled to strain rate values but related to physical mechanisms like the retarded movement of water in capillary systems and delayed microcracking. The constitutive law is fully triaxial and implemented into explicit finite element codes for the investigation of a wide range of concrete structures exposed to impact and explosions. The current setup models spallation experiments with concrete specimen [2]. The results of such experiments are mainly related to the dynamic tensile strength and the crack energy of concrete which may be derived from, e.g., the velocity of spalled concrete fragments. The experimental results are compared to the VERD model and two further constitutive laws implemented in LS-Dyna. The results indicate that both viscosity and retarded damage are required for a realistic description of the material behaviour of concrete exposed to high strain effects [3].

  12. Development of quantitative PCR and metagenomics-based approaches for strain quantification of a defined mixed-strain starter culture.

    Science.gov (United States)

    Johansen, Pernille; Vindeløv, Jannik; Arneborg, Nils; Brockmann, Elke

    2014-05-01

    Although the strain composition of mixed cultures may hugely affect production of various fermented foods, such as e.g. cheese, tools for investigating it have so far been limited. In this study, two new approaches for quantification of seven Lactococcus lactis subsp. cremoris strains (S1-S7) in a defined mixed-strain starter culture were developed and verified. By mapping NGS reads from 47 sequenced L. lactis strains to de novo assembly contigs of the seven strains, two strain-specific sequence regions (SEQ1 and SEQ2) were identified for each strain for qPCR primer design (A1 and A2). The qPCR assays amplified their strain-specific sequence region target efficiently. Additionally, high reproducibility was obtained in a validation sample containing equal amounts of the seven strains, and assay-to-assay coefficients of variance (CVs) for six (i.e. S1, S2, S4-S7) of the seven strains correlated to the inter-plate CVs. Hence, at least for six strains, the qPCR assay design approach was successful. The metagenomics-based approach quantified the seven strains based on average coverage of SEQ1 and SEQ2 by mapping sequencing reads from the validation sample to the strain-specific sequence regions. Average coverages of the SEQ1 and SEQ2 in the metagenomics data showed CVs of ≤17.3% for six strains (i.e. S1-S4, S6, S7). Thus, the metagenomics-based quantification approach was considered successful for six strains, regardless of the strain-specific sequence region used. When comparing qPCR- and metagenomics-based quantifications of the validation sample, the identified strain-specific sequence regions were considered suitable and applicable for quantification at a strain level of defined mixed-strain starter cultures.

  13. Brucella abortus Strain 2308 Wisconsin Genome: Importance of the Definition of Reference Strains

    Science.gov (United States)

    Suárez-Esquivel, Marcela; Ruiz-Villalobos, Nazareth; Castillo-Zeledón, Amanda; Jiménez-Rojas, César; Roop II, R. Martin; Comerci, Diego J.; Barquero-Calvo, Elías; Chacón-Díaz, Carlos; Caswell, Clayton C.; Baker, Kate S.; Chaves-Olarte, Esteban; Thomson, Nicholas R.; Moreno, Edgardo; Letesson, Jean J.; De Bolle, Xavier; Guzmán-Verri, Caterina

    2016-01-01

    Brucellosis is a bacterial infectious disease affecting a wide range of mammals and a neglected zoonosis caused by species of the genetically homogenous genus Brucella. As in most studies on bacterial diseases, research in brucellosis is carried out by using reference strains as canonical models to understand the mechanisms underlying host pathogen interactions. We performed whole genome sequencing analysis of the reference strain B. abortus 2308 routinely used in our laboratory, including manual curated annotation accessible as an editable version through a link at https://en.wikipedia.org/wiki/Brucella#Genomics. Comparison of this genome with two publically available 2308 genomes showed significant differences, particularly indels related to insertional elements, suggesting variability related to the transposition of these elements within the same strain. Considering the outcome of high resolution genomic techniques in the bacteriology field, the conventional concept of strain definition needs to be revised. PMID:27746773

  14. International Clostridium difficile animal strain collection and large diversity of animal associated strains

    DEFF Research Database (Denmark)

    Janezic, Sandra; Zidaric, Valerija; Pardon, Bart;

    2014-01-01

    Background: Clostridium difficile is an important cause of intestinal infections in some animal species and animals might be a reservoir for community associated human infections. Here we describe a collection of animal associated C. difficile strains from 12 countries based on inclusion criteria......; 10 countries). Conclusions: This results show that although PCR ribotype 078 is often reported as the major animal C. difficile type, especially in pigs, the variability of strains in pigs and other animal hosts is substantial. Most common human PCR ribotypes (014/020 and 002) are also among most...... prevalent animal associated C. difficile strains worldwide. The widespread dissemination of toxigenic C. difficile and the considerable overlap in strain distribution between species furthers concerns about interspecies, including zoonotic, transmission of this critically important pathogen....

  15. Strain-dependent induction of cytokine profiles in the gut by orally administered Lactobacillus strains

    NARCIS (Netherlands)

    Maassen, C.B.M.; Holten-Neelen, C. van; Balk, F.; Bak-Glashouwer, M.-J.H. den; Leer, R.J.; Laman, J.D.; Boersma, W.J.A.; Claassen, E.

    2000-01-01

    Different Lactobacillus strains are frequently used in consumer food products. In addition, recombinant lactobacilli which contain novel expression vectors can now be used in immunotherapeutic applications such as oral vaccination strategies and in T cell tolerance induction approaches for autoimmun

  16. The principle of strain reconstruction tomography: Determination of quench strain distribution from diffraction measurements

    International Nuclear Information System (INIS)

    The evaluation of residual elastic strain within the bulk of engineering components or natural objects is a challenging task, since in general it requires mapping a six-component tensor quantity in three dimensions. A further challenge concerns the interpretation of finite resolution data in a way that is commensurate and non-contradictory with respect to continuum deformation models. A practical solution for this problem, if it is ever to be found, must include efficient measurement interpretation and data reduction techniques. We describe the principle of strain tomography by high-energy X-ray diffraction, i.e. reconstruction of the higher dimensional distribution of strain within an object from multiple scans in lower dimensions, and illustrate the application of this principle to a simple case of reconstruction of an axisymmetric residual strain state induced in a cylindrical sample by quenching. The underlying principle of the analysis method presented in this paper allows generalisation to more complex situations

  17. The principle of strain reconstruction tomography: Determination of quench strain distribution from diffraction measurements

    Energy Technology Data Exchange (ETDEWEB)

    Korsunsky, Alexander M. [Department of Engineering Science, University of Oxford, Parks Road, Oxford, Oxon OX1 3PJ (United Kingdom)]. E-mail: alexander.korsunsky@eng.ox.ac.uk; Vorster, Willem J.J. [Department of Engineering Science, University of Oxford, Parks Road, Oxford, Oxon OX1 3PJ (United Kingdom); Zhang, Shu Yan [Department of Engineering Science, University of Oxford, Parks Road, Oxford, Oxon OX1 3PJ (United Kingdom); Dini, Daniele [Department of Engineering Science, University of Oxford, Parks Road, Oxford, Oxon OX1 3PJ (United Kingdom); Latham, David [Department of Engineering Science, University of Oxford, Parks Road, Oxford, Oxon OX1 3PJ (United Kingdom); Golshan, Mina [Synchrotron Radiation Source, Daresbury Laboratory, Keckwick Lane, Warrington WA4 4AD (United Kingdom); Liu, Jian [Department of Chemistry, University of Durham, South Road, Durham DH1 3LE (United Kingdom); Kyriakoglou, Yannis [Rolls-Royce plc, P.O. Box 31, Derby DE24 8BJ (United Kingdom); Walsh, Michael J. [Rolls-Royce plc, P.O. Box 31, Derby DE24 8BJ (United Kingdom)

    2006-05-15

    The evaluation of residual elastic strain within the bulk of engineering components or natural objects is a challenging task, since in general it requires mapping a six-component tensor quantity in three dimensions. A further challenge concerns the interpretation of finite resolution data in a way that is commensurate and non-contradictory with respect to continuum deformation models. A practical solution for this problem, if it is ever to be found, must include efficient measurement interpretation and data reduction techniques. We describe the principle of strain tomography by high-energy X-ray diffraction, i.e. reconstruction of the higher dimensional distribution of strain within an object from multiple scans in lower dimensions, and illustrate the application of this principle to a simple case of reconstruction of an axisymmetric residual strain state induced in a cylindrical sample by quenching. The underlying principle of the analysis method presented in this paper allows generalisation to more complex situations.

  18. A wide extent of inter-strain diversity in virulent and vaccine strains of alphaherpesviruses.

    Directory of Open Access Journals (Sweden)

    Moriah L Szpara

    2011-10-01

    Full Text Available Alphaherpesviruses are widespread in the human population, and include herpes simplex virus 1 (HSV-1 and 2, and varicella zoster virus (VZV. These viral pathogens cause epithelial lesions, and then infect the nervous system to cause lifelong latency, reactivation, and spread. A related veterinary herpesvirus, pseudorabies (PRV, causes similar disease in livestock that result in significant economic losses. Vaccines developed for VZV and PRV serve as useful models for the development of an HSV-1 vaccine. We present full genome sequence comparisons of the PRV vaccine strain Bartha, and two virulent PRV isolates, Kaplan and Becker. These genome sequences were determined by high-throughput sequencing and assembly, and present new insights into the attenuation of a mammalian alphaherpesvirus vaccine strain. We find many previously unknown coding differences between PRV Bartha and the virulent strains, including changes to the fusion proteins gH and gB, and over forty other viral proteins. Inter-strain variation in PRV protein sequences is much closer to levels previously observed for HSV-1 than for the highly stable VZV proteome. Almost 20% of the PRV genome contains tandem short sequence repeats (SSRs, a class of nucleic acids motifs whose length-variation has been associated with changes in DNA binding site efficiency, transcriptional regulation, and protein interactions. We find SSRs throughout the herpesvirus family, and provide the first global characterization of SSRs in viruses, both within and between strains. We find SSR length variation between different isolates of PRV and HSV-1, which may provide a new mechanism for phenotypic variation between strains. Finally, we detected a small number of polymorphic bases within each plaque-purified PRV strain, and we characterize the effect of passage and plaque-purification on these polymorphisms. These data add to growing evidence that even plaque-purified stocks of stable DNA viruses exhibit

  19. Screening and Evaluation of Polyhydroxybutyrate-Producing Strains from Indigenous Isolate Cupriavidus taiwanensis Strains

    OpenAIRE

    Om-Murugan Janarthanan; Chi-Wei Lo; Chin-Kuei Huang; Ho-Shing Wu; Yi-Ming Sun; Wei-Chuan Chen; Yu-Hong Wei

    2011-01-01

    Polyhydroxyalkanoate (PHA) is a biodegradable material with many potential biomedical applications, including medical implants and drug delivery. This study developed a system for screening production strains in order to optimize PHA production in Cupriavidus taiwanensis 184, 185, 186, 187, 204, 208, 209 and Pseudomona oleovorans ATCC 29347. In this study, Sudan black B staining, Infrared (IR) and Gas Chromatography (GC) analysis indicated that the best strain for PHA synthesis is C. taiwanen...

  20. Influence of strained drain on performance of ballistic channel devices

    International Nuclear Information System (INIS)

    We have studied the performance of ballistic channel diodes with strained channel or drain, based on Monte Carlo simulation. A larger increase in drain current and mean velocity of electrons in the drain region is observed for strained drain diode compared to strained channel diode. This is due to reduction of intervalley scattering and electrons transported with smaller transverse effective mass in the strained drain. This also results in lower heat generation and parasitic resistances in strained drain. We conclude that the strained drain is an efficient way to improve electrical characteristics of devices with ballistic channel. (paper)

  1. Hole doped Dirac states in silicene by biaxial tensile strain

    KAUST Repository

    Kaloni, Thaneshwor P.

    2013-03-11

    The effects of biaxial tensile strain on the structure, electronic states, and mechanical properties of silicene are studied by ab-initio calculations. Our results show that up to 5% strain the Dirac cone remains essentially at the Fermi level, while higher strain induces hole doped Dirac states because of weakened Si–Si bonds. We demonstrate that the silicene lattice is stable up to 17% strain. It is noted that the buckling first decreases with the strain (up to 10%) and then increases again, which is accompanied by a band gap variation. We also calculate the Grüneisen parameter and demonstrate a strain dependence similar to that of graphene.

  2. Generalizing the Fermi velocity of strained graphene from uniform to nonuniform strain

    Energy Technology Data Exchange (ETDEWEB)

    Oliva-Leyva, M., E-mail: moliva@fisica.unam.mx [Departamento de Física-Química, Instituto de Física, Universidad Nacional Autónoma de México (UNAM), Apartado Postal 20-364, 01000 México, Distrito Federal (Mexico); Naumis, Gerardo G., E-mail: naumis@fisica.unam.mx [Departamento de Física-Química, Instituto de Física, Universidad Nacional Autónoma de México (UNAM), Apartado Postal 20-364, 01000 México, Distrito Federal (Mexico); School of Physics Astronomy and Computational Sciences, George Mason University, Fairfax, VA 22030 (United States)

    2015-10-23

    The relevance of the strain-induced Dirac point shift to obtain the appropriate anisotropic Fermi velocity of strained graphene is demonstrated. Then a critical revision of the available effective Dirac Hamiltonians is made by studying in detail the limiting case of a uniform strain. An effective Dirac Hamiltonian for nonuniform strain is thus reported, which takes into account all strain-induced effects: changes in the nearest-neighbor hopping parameters, the reciprocal lattice deformation and the true shift of the Dirac point. Pseudomagnetic fields are thus explained by means of position-dependent Dirac cones, whereas complex gauge fields appear as a consequence of a position-dependent Fermi velocity. Also, position-dependent Fermi velocity effects on the spinor wavefunction are considered for interesting cases of deformations such as flexural modes. - Highlights: • The relevance of the strain-induced Dirac point shift to obtain the anisotropic Fermi velocity is shown. • An appropriate expression of the position-dependent Fermi velocity is reported. • A position-dependent Fermi velocity induces an inhomogeneity in the carrier probability density.

  3. Creep strain and strain rate response of 2219 Al alloy at high stress levels

    Energy Technology Data Exchange (ETDEWEB)

    Taminger, K.M.B.; Wagner, J.A.; Barry Lisagor, W. [National Aeronautics and Space Administration, Hampton, VA (United States). Langley Research Center

    2000-07-01

    As a result of high localized plastic deformation experienced during proof testing in an international space station connecting module, a study was undertaken to determine the deformation response of a 2219-T851 roll forging. After prestraining 2219-T851 Al specimens to simulate strains observed during the proof testing, creep tests were conducted in the temperature range from ambient temperature to 107 C (225 F) at stress levels approaching the ultimate tensile strength of 2219-T851 Al. Strain-time histories and strain rate responses were examined. The strain rate response was extremely high initially, but decayed rapidly, spanning as much as five orders of magnitude during primary creep. Select specimens were subjected to incremental step loading and exhibited initial creep rates of similar magnitude for each load step. Although the creep rates decreased quickly at all loads, the creep rates dropped faster and reached lower strain rate levels for lower applied loads. The initial creep rate and creep rate decay associated with primary creep were similar for specimens with and without prestrain; however, prestraining (strain hardening) the specimens, as in the aforementioned proof test, resulted in significantly longer creep life. (orig.)

  4. Creep Strain and Strain Rate Response of 2219 Al Alloy at High Stress Levels

    Science.gov (United States)

    Taminger, Karen M. B.; Wagner, John A.; Lisagor, W. Barry

    1998-01-01

    As a result of high localized plastic deformation experienced during proof testing in an International Space Station connecting module, a study was undertaken to determine the deformation response of a 2219-T851 roll forging. After prestraining 2219-T851 Al specimens to simulate strains observed during the proof testing, creep tests were conducted in the temperature range from ambient temperature to 107 C (225 F) at stress levels approaching the ultimate tensile strength of 2219-T851 Al. Strain-time histories and strain rate responses were examined. The strain rate response was extremely high initially, but decayed rapidly, spanning as much as five orders of magnitude during primary creep. Select specimens were subjected to incremental step loading and exhibited initial creep rates of similar magnitude for each load step. Although the creep rates decreased quickly at all loads, the creep rates dropped faster and reached lower strain rate levels for lower applied loads. The initial creep rate and creep rate decay associated with primary creep were similar for specimens with and without prestrain; however, prestraining (strain hardening) the specimens, as in the aforementioned proof test, resulted in significantly longer creep life.

  5. Stress-strain characteristics of materials at high strain rates. Part II. Experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Ripperger, E. A. [Texas. Univ., Austin, TX (US). Structural Mechanics Research Lab.

    1958-08-29

    These two reports were issued separately, but are cataloged as a unit. A photoelectric method for measuring displacements during high-velocity impacts is described. The theory of the system is discussed in detail, and a prototype system which was built and tested is described. The performance of the prototype system is evaluated by comparing the results which it gives with results obtained by other methods of measurement. The system was found capable of a resolution of at least 0.01 inches. static and dynamic stress-strain characteristics of seven high polymers, polyethylene, teflon, nylon, tenite M, tenite H, polystyrene, and saran, plus three metals, lead, copper, and aluminum, are described and compared by means of stress-strain curves and photographs. Data are also presented which show qualitatively the effects produced on stress-strain characteristics by specimen configuration, temperature, and impact velocity. It is shown that there is a definite strain-rate effect for all these materials except polystyrene. The effect is one of an apparent stiffening of the material with increasing strain rate, which is similar to the effect produced by lowering the temperature. The stress-strain measurements are examined critically, inconsistencies are pointed out, and possible sources of error suggested. Values of yield stress, modulus of elasticity and energy absorption for all materials (except copper and aluminum), specimen configurations, temperatures, and impact velocities included in the investigation are tabulated.

  6. Strain mapping near a triple junction in strained Ni-based alloy using EBSD and biaxial nanogauges

    Energy Technology Data Exchange (ETDEWEB)

    Clair, A. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France); Foucault, M.; Calonne, O. [Areva ANP, Centre Technique Departement Corrosion-Chimie, 30 Bd de l' industrie, BP 181, 71205 Le Creusot (France); Lacroute, Y.; Markey, L.; Salazar, M.; Vignal, V. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France); Finot, E., E-mail: Eric.Finot@u-bourgogne.fr [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France)

    2011-05-15

    Research highlights: > Surface strains measured using nanogauge were compared to the texture obtained by EBSD. > Statistics of the principal strain discern the grains according to the Schmid factor. > Strain hotspots were localized near a triple junction of alloy 600 under tensile loading. > Asymetrical profile of the GB strains is a criterion for surface cracking initiation. - Abstract: A key element for analyzing the crack initiation in strained polycrystalline alloys is the local quantification of the surface strain distribution according to the grain texture. Using electron backscattered diffraction, the local microstructure was determined to both localize a triple junction and deduce the local Schmid factors. Kernel average misorientation (KAM) was also used to map the areas of defect concentration. The maximum principal strain and the in-plane shear strain were quantified using the biaxial nanogauge. Distortions of the array of nanodots used as spot markers were analyzed near the triple junction. The crystallographic orientation and the surface strain were then investigated both statistically for each grain and locally at the grain boundaries. The superimposition of microstructure and strain maps allows the high strain gradient (reaching 3-fold the applied strain) to be localized at preferential grain boundaries near the triple junction. The Schmid factors and the KAM were compared to the maximum principal strain and the in-plane shear strain respectively. The polycrystalline deformation was attributable first to the rotation of some grains, followed by the elongation of all grains along their preferential activated slip systems.

  7. EDITORIAL: Excelling under strain: band engineering in nanomaterials Excelling under strain: band engineering in nanomaterials

    Science.gov (United States)

    Demming, Anna

    2013-08-01

    A little stress or strain has been known to improve the performance of athletes, actors and of course nanomaterials alike. In fact strain in silicon is now a major engineering tool for improving the performance of devices, and is ubiquitously used in device design and fabrication. Strain engineering alters a material's band structure, a model of electron behaviour that describes how as atoms come together in a solid, their discrete electron orbitals overlap to ultimately give rise to bands of allowed energy levels. In a strained crystal lattice of silicon or silicon germanium the distance between atoms in the lattice is greater than usual and the bands of allowed energy levels change. This July marks 100 years since Bohr submitted his paper 'On the constitution of atoms and molecules' [1] where he describes the structure of the atom in terms of discrete allowed energy levels. The paper was a seminal contribution to the development of quantum mechanics and laid the initial theoretical precepts for band gap engineering in devices. In this issue Nrauda and a collaboration of researchers in Europe and Australia study the growth of defect-free SiGe islands on pre-patterned silicon [2]. They analyse the strain in the islands and determine at what point lattice dislocations set in with a view to informing implementation of strain engineering in devices. The effects of strain on band structure in silicon and germanium were already studied and reported in the 1950s [3, 4]. Since then the increasing focus on nanoscale materials and the hunger for control of electronic properties has prompted further study of strain effects. The increased surface area to volume ratio in nanostructures changes the strain behaviour with respect to bulk materials, and this can also be exploited for handling and fine tuning strain to manipulate material properties. It is perhaps no surprise that graphene, one of the most high-profile materials in current nanotechnology research, has attracted

  8. Techniques for increasing boron fiber fracture strain

    Science.gov (United States)

    Dicarlo, J. A.

    1977-01-01

    Improvement in the strain-to-failure of CVD boron fibers is shown possible by contracting the tungsten boride core region and its inherent flaws. The results of three methods are presented in which etching and thermal processing techniques were employed to achieve core flaw contraction by internal stresses available in the boron sheath. After commercially and treatment induced surface flaws were removed from 203 micrometers (8 mil) fibers, the core flaw was observed to be essentially the only source of fiber fracture. Thus, fiber strain-to-failure was found to improve by an amount equal to the treatment induced contraction on the core flaw. Commercial feasibility considerations suggest as the most cost effective technique that method in which as-produced fibers are given a rapid heat treatment above 700 C. Preliminary results concerning the contraction kinetics and fracture behavior observed are presented and discussed both for high vacuum and argon gas heat treatment environments.

  9. Chaotic desynchronization of multi-strain diseases

    CERN Document Server

    Schwartz, I B; Cummings, D A T; Billings, L; McCrary, M; Burke, D S; Schwartz, Ira B.; Shaw, Leah B.; Cummings, Derek A. T.; Billings, Lora; Crary, Marie Mc; Burke, Donald S.

    2005-01-01

    Multi-strain diseases are diseases that consist of several strains, or serotypes. The serotypes may interact by antibody-dependent enhancement (ADE), in which infection with a single serotype is asymptomatic, but infection with a second serotype leads to serious illness accompanied by greater infectivity. It has been observed from serotype data of dengue hemorrhagic fever that outbreaks of the four serotypes occur asynchronously. Both autonomous and seasonally driven outbreaks were studied in a model containing ADE. For sufficiently small ADE, the number of infectives of each serotype synchronizes, with outbreaks occurring in phase. When the ADE increases past a threshold, the system becomes chaotic, and infectives of each serotype desynchronize. However, certain groupings of the primary and second ary infectives remain synchronized even in the chaotic regime.

  10. Organic chemistry. Strain-release amination.

    Science.gov (United States)

    Gianatassio, Ryan; Lopchuk, Justin M; Wang, Jie; Pan, Chung-Mao; Malins, Lara R; Prieto, Liher; Brandt, Thomas A; Collins, Michael R; Gallego, Gary M; Sach, Neal W; Spangler, Jillian E; Zhu, Huichin; Zhu, Jinjiang; Baran, Phil S

    2016-01-15

    To optimize drug candidates, modern medicinal chemists are increasingly turning to an unconventional structural motif: small, strained ring systems. However, the difficulty of introducing substituents such as bicyclo[1.1.1]pentanes, azetidines, or cyclobutanes often outweighs the challenge of synthesizing the parent scaffold itself. Thus, there is an urgent need for general methods to rapidly and directly append such groups onto core scaffolds. Here we report a general strategy to harness the embedded potential energy of effectively spring-loaded C-C and C-N bonds with the most oft-encountered nucleophiles in pharmaceutical chemistry, amines. Strain-release amination can diversify a range of substrates with a multitude of desirable bioisosteres at both the early and late stages of a synthesis. The technique has also been applied to peptide labeling and bioconjugation.

  11. Strain monitoring of a composite wing

    Science.gov (United States)

    Strathman, Joseph; Watkins, Steve E.; Kaur, Amardeep; Macke, David C.

    2016-04-01

    An instrumented composite wing is described. The wing is designed to meet the load and ruggedness requirements for a fixed-wing unmanned aerial vehicle (UAV) in search-and-rescue applications. The UAV supports educational systems development and has a 2.1-m wingspan. The wing structure consists of a foam core covered by a carbon-fiber, laminate composite shell. To quantify the wing characteristics, a fiber-optic strain sensor was surface mounted to measure distributed strain. This sensor is based on Rayleigh scattering from local index variations and it is capable of high spatial resolution. The use of the Rayleigh-scattering fiber-optic sensors for distributed measurements is discussed.

  12. Dynamic strain aging in Haynes 282 superalloy

    Directory of Open Access Journals (Sweden)

    Hörnqvist Magnus

    2014-01-01

    Full Text Available Haynes 282 is a newly introduced Ni-based superallony, developed to provide a combination of high-temperature mechanical properties, thermal stability and processability. The present contribution investigates the effect of dynamic strain aging (DSA on the deformation behaviour of Haynes 282 during monotonic and cyclic loading. It is shown that DSA (presumably related to carbon diffusion based on rough estimates of the activation energy completely dominates the development of the stress during cycling at intermediate temperatures, leading to extensive cyclic hardening and serrated yielding. However, no clear effects on the fatigue life or the resulting dislocation structure could be observed. The tensile properties were not severely affected, in spite of the presence of extensive serrated yielding, although a reduction in ductility was observed in the DSA temperature regime. During monotonic loading at lower strain rates indications of an additional DSA mechanism due to substitutional elements were observed.

  13. Magnetic properties on strained manganite thin film

    Science.gov (United States)

    Prajapat, C. L.; Singh, M. R.; Gupta, S. K.; Bhattacharya, D.; Basu, S.; Ravikumar, G.

    2014-04-01

    Structural and magnetic studies on La2/3Sr1/3MnO3 (LSMO) epitaxial films grown on STO (100) and MgO (100) substrates by Pulsed Laser Deposition are presented. Due to larger interface strain, the grain size of LSMO on MgO is much smaller than that on STO substrate. However, anisotropy energy produced as a result of in plane tensile strain is much larger in case of the films deposited on MgO in such a way that the blocking (irreversibility) temperature and the coercive fields inferred from temperature and magnetic field dependent magnetization measurements are significantly higher. The importance of this result for the memory applications is highlighted.

  14. A Tunable Strain Sensor Using Nanogranular Metals

    Directory of Open Access Journals (Sweden)

    Friedemann Völklein

    2010-11-01

    Full Text Available This paper introduces a new methodology for the fabrication of strain-sensor elements for MEMS and NEMS applications based on the tunneling effect in nano-granular metals. The strain-sensor elements are prepared by the maskless lithography technique of focused electron-beam-induced deposition (FEBID employing the precursor trimethylmethylcyclopentadienyl platinum [MeCpPt(Me3]. We use a cantilever-based deflection technique to determine the sensitivity (gauge factor of the sensor element. We find that its sensitivity depends on the electrical conductivity and can be continuously tuned, either by the thickness of the deposit or by electron-beam irradiation leading to a distinct maximum in the sensitivity. This maximum finds a theoretical rationale in recent advances in the understanding of electronic charge transport in nano-granular metals.

  15. Development of the brine shrimp Artemia is accelerated during spaceflight

    Science.gov (United States)

    Spooner, B. S.; Metcalf, J.; DeBell, L.; Paulsen, A.; Noren, W.; Guikema, J. A.

    1994-01-01

    Developmentally arrested brine shrimp cysts have been reactivated during orbital spaceflight on two different Space Shuttle missions (STS-50 and STS-54), and their subsequent development has been compared with that of simultaneously reactivated ground controls. Flight and control brine shrimp do not significantly differ with respect to hatching rates or larval morphology at the scanning and transmission EM levels. A small percentage of the flight larvae had defective nauplier eye development, but the observation was not statistically significant. However, in three different experiments on two different flights, involving a total of 232 larvae that developed in space, a highly significant difference in degree of flight to control development was found. By as early as 2.25 days after reactivation of development, spaceflight brine shrimp were accelerated, by a full instar, over ground control brine shrimp. Although developing more rapidly, flight shrimp grew as long as control shrimp at each developmental instar or stage.

  16. Prospects of Artemia culture in the coastal zone

    Digital Repository Service at National Institute of Oceanography (India)

    Royan, J.P.

    stream_size 10 stream_content_type text/plain stream_name India_EEZ_1996_132.pdf.txt stream_source_info India_EEZ_1996_132.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

  17. Toxicity of heavy metals to brine shrimp Artemia

    Digital Repository Service at National Institute of Oceanography (India)

    Gajbhiye, S.N.; Hirota, R.

    stream_size 8 stream_content_type text/plain stream_name J_Indian_Fish_Assoc_20_43.pdf.txt stream_source_info J_Indian_Fish_Assoc_20_43.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

  18. Strain-specific chemotaxis of Azospirillum spp.

    OpenAIRE

    Reinhold, B; Hurek, T; Fendrik, I

    1985-01-01

    Chemotactic responses of three Azospirillum strains originating from different host plants were compared to examine the possible role of chemotaxis in the adaptation of these bacteria to their respective hosts. The chemotaxis to several sugars, amino acids, and organic acids was determined qualitatively by an agar plate assay and quantitatively by a channeled-chamber technique. High chemotactic ratios, up to 40, were obtained with the latter technique. The chemotactic response did not rely up...

  19. Plane strain problem in microstretch elastic solid

    Indian Academy of Sciences (India)

    Rajneesh Kumar; Ranjit Singh; T K Chadha

    2003-12-01

    The eigenvalue approach is developed for the two-dimensional plane strain problem in a microstretch elastic medium. Applying Laplace and Fourier transforms, an infinite space subjected to a concentrated force is studied. The integral transforms are inverted using a numerical technique to get displacement, force stress, couple stress and first moment, which are also shown graphically. The results of micropolar elasticity are deduced as a special case from the present formulation.

  20. Strain weakening enables continental plate tectonics

    OpenAIRE

    Gueydan, Frédéric; Précigout, Jacques; Montesi, Laurent G.J.

    2014-01-01

    International audience Much debate exists concerning the strength distribution of the continental lithosphere, how it controls lithosphere-scale strain localization and hence enables plate tectonics. No rheological model proposed to date is comprehensive enough to describe both the weakness of plate boundary and rigid-like behaviour of plate interiors. Here we show that the duality of strength of the lithosphere corresponds to different stages of microstructural evolution. Geological const...