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Sample records for colony forming ability

  1. Post-UV colony-forming ability of normal fibroblast strains and of the xeroderma pigmentosum group G strain

    International Nuclear Information System (INIS)

    Barrett, S.F.; Tarone, R.E.; Moshell, A.N.; Ganges, M.B.; Robbins, J.H.

    1981-01-01

    In xeroderma pigmentosum, an inherited disorder of defective DNA repair, post-uv colony-forming ability of fibroblasts from patients in complementation groups A through F correlates with the patients' neurological status. The first xeroderma pigmentosum patient assigned to the recently discovered group G had the neurological abnormalities of XP. Researchers have determined the post-uv colony-forming ability of cultured fibroblasts from this patient and from 5 more control donors. Log-phase fibroblasts were irradiated with 254 nm uv light from a germicidal lamp, trypsinized, and replated at known densities. After 2 to 4 weeks' incubation the cells were fixed, stained and scored for colony formation. The strains' post-uv colony-forming ability curves were obtained by plotting the log of the percent remaining post-uv colony-forming ability as a function of the uv dose. The post-uv colony-forming ability of 2 of the 5 new normal strains was in the previously defined control donor zone, but that of the other 3 extended down to the level of the most resistant xeroderma pigmentosum strain. The post-uv colony-forming ability curve of the group G fibroblasts was not significantly different from the curves of the group D fibroblast strains from patients with clinical histories similar to that of the group G patient

  2. Binucleate cell formation correlates to loss of colony-forming ability in X-irradiated cultured mammalian cells

    International Nuclear Information System (INIS)

    Sasaki, H.; Yoshinaga, H.; Kura, S.

    1986-01-01

    The relationship between binucleate cell formation and the loss of colony-forming ability was examined in several cultured mammalian cell lines irradiated with X rays. The maximum fraction of binucleate cells after X irradiation increased dose-dependently within the range in which reproductive cell death might predominate over interphase cell death. When the logarithm of percentage survival was plotted against the percentage binucleate cells, a similar correlation was found for all cell lines tested, with the exception of mouse leukemia L5178Y cells, the most radiosensitive cells used. These observations suggest that the fraction of binucleate cells in the cell population can serve as a measure of cellular radiation damage

  3. Loss of the ability to generate large burst-forming unit-like megakaryocytic colonies from thawed cord blood in semisolid cultures after short term suspension culture.

    Science.gov (United States)

    Eskola, M; Bäckman, S; Möttönen, S; Kekomäki, R

    2015-04-01

    Total colony-forming cells from thawed cord blood units (CBUs) include megakaryocytic colony-forming units (CFU-Mks), which survive the freezing process. The aim of this study was to evaluate whether different megakaryocytic progenitors from unseparated CBUs survive the freezing process and a short-term liquid culture. Thawed samples of CBUs were cultured in liquid medium. During the cultures, serial samples were drawn to assess the growth of different megakaryocytic progenitors in a semisolid collagen medium with identical cytokines as in the liquid medium. Megakaryocytic cells were detected using immunohistochemistry and flow cytometry. In suspension culture, the megakaryocytic progenitors almost completely lost the ability to generate large (burst-forming unit-like, BFU-like) megakaryocytic colonies in semisolid cultures (large colonies, median count per chamber d0: 7.25 vs. d7: 1.5; P culture in suspension resulted in the decline of small colonies as well (d7: 16.0 vs. d14: 5.75; P = 0.0088). Total CFU-Mk count declined from 23.3 (range 12.5-34.0) at d0 to 7.25 (range 1.0-13.5) at d14 (P culture after a short suspension culture. Small CFU-Mks were observed throughout the cultures. It may be that the BFU-Mk colonies matured and acquired CFU-Mk behaviour. © 2014 International Society of Blood Transfusion.

  4. Effect of poly-A:U, dextran sulfate and yeast RNA on the bone marrow colony-forming ability in irradiated mice

    International Nuclear Information System (INIS)

    Chernyavskij, V.I.; Lysenko, A.I.; Kulakova, G.S.

    1977-01-01

    It has been shown, that poly-A:U, dextran sulfate and yeast RNA increased a number of endogenic colonies (COE) in the mouse spleen sublethally irradiated, as a result of, apparently, their mitogenic effect on proliferous COE. The preparations did not affect the number of exogenic colonies when introducting them together with transfer of syngenic cells of bone marrow, taken from the intact donors. Dextran sulfate increased 2.7 times the number of the endogenic colonies in the spleens of nonuniformly irradiated mice mainly due to the COE migration from protected bone marrow areas. The complex of poly-A:U and yest RNA in such experiment type were ineffective. One of the most important factors in the mechanism of the dextran sulfate adjuvant activity possibly is its ability to increase migration potencies of the stem blood-forming cells

  5. Photoreactivation of ultraviolet light-induced damage in cultured fish cells as revealed by increased colony forming ability and decreased content of pyrimidine dimers

    International Nuclear Information System (INIS)

    Shima, A.; Ikenaga, M.; Egami, N.

    1981-01-01

    Cultured cells derived from a goldfish were irradiated with 254 nm ultraviolet light. Cell survival and splitting of pyrimidine dimers after photoreactivation treatment with white fluorescent lamps were examined by colony forming ability and by a direct dimer assay, respectively. When UV-irradiated (5 J/m 2 ) cells were illuminated by photoreactivating light, cell survival was enhanced up to a factor of 9(40 min) followed by a decline after prolonged exposures. Exposure of UV-irradiated (15 J/m 2 ) cells to radiation from white fluorescent lamps reduced the amounts of thymine-containing dimers in a photoreactivating fluence dependent manner, up to about 60% reduction at 120 min exposure. Keeping UV-irradiated cells in the dark for up to 120 min did not affect either cell survival or the amount of pyrimidine dimers in DNA, indicating that there were not detectable levels of a dark-repair system in the cells under our conditions. Correlation between photoreactivation of colony forming ability and photoreactivation of the pyrimidine dimers was demonstrated, at least at relatively low fluences of photoreactivating light. (author)

  6. Photoreactivation of ultraviolet light-induced damage in cultured fish cells as revealed by increased colony forming ability and decreased content of pyrimidine dimers

    Energy Technology Data Exchange (ETDEWEB)

    Shima, A. (Shiga University of Medical Science, Otsu (Japan)); Ikenaga, M. (Osaka Univ. (Japan). Faculty of Medicine); Nikaido, O.; Takebe, H. (Kyoto Univ. (Japan)); Egami, N. (Tokyo Univ. (Japan). Faculty of Science)

    1981-03-01

    Cultured cells derived from a goldfish were irradiated with 254 nm ultraviolet light. Cell survival and splitting of pyrimidine dimers after photoreactivation treatment with white fluorescent lamps were examined by colony forming ability and by a direct dimer assay, respectively. When UV-irradiated (5 J/m/sup 2/) cells were illuminated by photoreactivating light, cell survival was enhanced up to a factor of 9(40 min) followed by a decline after prolonged exposures. Exposure of UV-irradiated (15 J/m/sup 2/) cells to radiation from white fluorescent lamps reduced the amounts of thymine-containing dimers in a photoreactivating fluence dependent manner, up to about 60% reduction at 120 min exposure. Keeping UV-irradiated cells in the dark for up to 120 min did not affect either cell survival or the amount of pyrimidine dimers in DNA, indicating that there were not detectable levels of a dark-repair system in the cells under our conditions. Correlation between photoreactivation of colony forming ability and photoreactivation of the pyrimidine dimers was demonstrated, at least at relatively low fluences of photoreactivating light.

  7. Effect of X-Rays on Growth Rate of Rose Shoot Cultures and the Ability of Isolated Protoplasts to Form Cell Colonies

    International Nuclear Information System (INIS)

    Moustafa, R. A. K.

    2004-01-01

    The popularity of rose as a garden plant, allied with its use in the production of cut flowers and also as a source of aromatic rose oils, make it one of the most important ornamental crops. Roses, however, have suffered from a narrow genetic base to which only few species have contributed significantly. In vitro culture of plants might facilitate the improvement of rose via the exploitation of somaclonal variation to generate new genetic variability and selection within the variation for desirable traits. The application of mutagens for in vitro cultures, in addition to the induced mutations, may lead to increase the somaclonal variation, thus providing additional variation for selection. On the other hand, plant protoplasts offer exciting possibilities to establish in vitro selection programs based on single cells. Induced variation in isolated protoplasts using mutagen agents may be one mean to select useful mutants. Thus the present experiments were conducted to determine the effect of X-rays on shoot cultures and the isolated protoplasts of rose (Rosa sp.). The materials consisted of the three rose varieties Rosa wichuriana, Paricer charm and Heckenzauber.The applied doses were 0, 10, 20, 30, 40, 50 and 60 Gy. Obtained results indicated that the genotypes differed in their sensitivity to X-rays. Rosa wichuriana seemed to be the most sensitive variety to radiation, where a dose of 20 Gy caused approximately 50% reduction in growth rate of shoot cultures, while the same dose decreased the growth rate of Paricer charm only by 25% and did not affect the growth of Heckenzauber. Results also revealed that the ability of irradiated protoplasts to form cell colonies increased when a dose of 10 Gy was performed. Doses higher than that level caused gradual decreasing in the forming of cell colonies, but however, the protoplasts could form colonies even when a dose of 60 Gy was applied. (Author)

  8. Effect of barbiturates on radiosensitivity of cells: a comparative study of electrophoretic mobility, colony forming ability and thymidine uptake on human amnion cells

    International Nuclear Information System (INIS)

    Lalwani, N.D.; Chaubal, K.A.

    1980-01-01

    Suspensions of human amnion cells were 60 Co γ-irradiated in the presence of phenobarbital or thiobarbital (50 μg/ml). The barbiturates protected the cells against the dose-dependent reduction in electrophoretic mobility (EPM) observed 4 hours after irradiation of untreated cells, although there was an initial decrease in the EPM of treated cells followed by recovery. Treated irradiated cells exhibited greater colony-forming ability than the untreated cells. Pentobarbital and phenobarbital had similar effects, but thiobarbital was not so effective. 3 H-TdR uptake increased within 4 hours of irradiation for the treated cells. The reproductive capacity of the cells was retained at doses as high as 500 rad. The results are discussed with reference to the effects of anaesthetics on cell membranes. (U.K.)

  9. Enhanced radiosensitivity of cultured fibroblasts from ataxia telangiectasia heterozygotes manifested by defective colony-forming ability and reduced DNA repair replication after hypoxic γ-irradiation

    International Nuclear Information System (INIS)

    Paterson, M.C.; Anderson, A.K.; Smith, B.P.; Smith, P.J.

    1979-01-01

    We have measured the sensitivity to γ-ray inactivation of diploid skin fibroblasts cultured from 10 persons in four families with ataxia telangiectasia (AT). Persons heterozygous for AT, including parents of afflicted patients, are not as yet detectable by any specific clinical or laboratory marker but are believed to constitute a substantial portion of the middle-aged cancer population. In one AT family, fibroblast strains from both parents exhibited a colony-forming ability after hypoxic irradiation which was intermediate between that displayed by five control strains from normal children and that from the affected child. In the remaining three families, cultures from only one parent were available; one parental strain displayed an intermediate survival capacity as above, whereas the other two responded normally. The homozygous recessive strains from the five afflicted children in the four families were all equally hypersensitive to hypoxic γ-ray inactivation. The three presumed AT heterozygous strains that displayed intermediate rayiosensitivity also carried out γ-rad-induced DNA repair replication to an extent intermediate between those in normals and AT homozygotes. These findings suggest that a numerically significant, cancer-prone subpopulation of humans carrying one normal and one abnormal AT gene may also be moderately sensitive to lethal effects of hypoxic γ-rays due to a defect in the enzymatic repair of DNA

  10. Observations of radiation-induced chromosome fragment loss in live mammalian cells in culture, and its effect on colony-forming ability

    International Nuclear Information System (INIS)

    Grote, S.J.; Joshi, G.P.; Revell, S.H.; Shaw, C.A.

    1981-01-01

    A preceding paper (Grote, Joshi, Revell and Shaw 1981) describe a method for the direct scrutiny of live cultured mammalian cells with a microscope, and reported that all diploid Syrian hamster cells (BHK 21 C13) of a sample given 1.4 Gy of 220 kV X-rays in G1 reached post-radiation mitosis without discernible abnormality, but then diverged in observed behaviour: descendant cells from some first mitoses continued to proliferate normally while cells from other first mitoses behaved abnormally and produced either slow-growth or stop-growth colonies. This paper completes the study of the same irradiated cell sample, and shows that these post-mitotic differences in clonogenic ability were related to acentric chromosome fragment losses at post-radiation mitosis, which were detected in live daughter-cell pairs as micronuclei. The proportion of live daughter-cell pairs scored as deficient was at least 80 per cent of the proportion of comparable fixed-and-stained mitoses with detected acentric fragments. (author)

  11. Colony form variation of Bacillus pumilus E601 after cultured and neutron irradiation

    International Nuclear Information System (INIS)

    Chen Xiaoming; Wei Baoli; Zhang Jianguo

    2008-01-01

    The distribution of two colony forms of Bacillus pumilus E601 and the effect of neutron irradiation on the colony form were reported. The translucent and opaque colonies were cultured several generations to observe the proportion of two form colonies. The spores of opaque colony were irradiated at 80, 800 and 2000 Gy of fast neutron from CFBR-II pulse pile, and the survivors of opaque colony were irradiated again at the same doses. The results showed that: (1) Bacillus pumilus E601 observed two types of colony form: translucent and opaque colony; (2) the translucent colony could produce both translucent and opaque colonies in equal, while the opaque colony couldn't produce translucent colony generally; (3) neutron irradiation could affect the colony form distribution. The ratio of survival translucent colony was increased with the increase of the first neutron irradiation doses, and the second neutron irradiation also increased the ratio of translucent colony. It was concluded that the instability of translucent colony was the main reason to produce two colony forms of Bacillus pumilus E601. The strain of translucent colony had a stronger ability to resist neutron irradiation than the opaque colony. (authors)

  12. Relationship of colony-stimulating activity to apparent kill of human colony-forming cells by irradiation and hydroxyurea

    International Nuclear Information System (INIS)

    Broxmeyer, H.E.; Galbraith, P.R.; Baker, F.L.

    1976-01-01

    Suspensions of human bone marrow cells were subjected to 137 Cs irradiation in vitro and then cultured in semisolid agar medium. Cultures of irradiated cells were stimulated with colony-stimulating activity (CSA) of different potencies, and it was found that the amount of stimulation applied to cultures influenced the apparent kill of colony-forming cells (CFC). It was also found that the effects of irradiation on colony formation were not confined to CFC kill since medium conditioned by cells during irradiation exhibited stimulatory and inhibitory properties after treatment by 600 and 1000 rads, respectively. Studies in which irradiated cells were pretreated with hydroxyurea indicated that CFC in the DNA synthetic phase of the cell cycle were particularly sensitive to low doses of irradiation. The proliferative capacity of CFC surviving 1000 rads was undiminished as judged by their ability to form large colonies. Estimates of CFC kill by hydroxyurea were also affected by the level of CSA

  13. Forms of Memory in Post-colonial Australia

    Directory of Open Access Journals (Sweden)

    Lyn McCredden

    2009-06-01

    Full Text Available there are many forms of memory in post-colonial Australia, and many kinds of haunting. This paper investigates the poetry of contemporary Indigenous poets Sam Wagan Watson and Tony Birch, and reads the script of the Federal Government’s February 2008 Apology to the Stolen Generations, asking how and why the nation should be haunted – historically and imaginatively - into the future.

  14. Triplex-forming ability of modified oligonucleotides

    DEFF Research Database (Denmark)

    Højland, Torben; Babu, Bolle Ravindra; Bryld, Torsten

    2007-01-01

    We present our studies on the ability of several different nucleotide analogs as triplex-forming oligonucleotides. The modifications tested include 4'-C-hydroxymethyl, LNA, 2'-amino-LNA and N2'-functionalized 2'-amino-LNA. Triplexes containing monomers of N2'-glycyl-functionalized 2'-amino-LNA ar...

  15. Effects of clothianidin on Bombus impatiens (Hymenoptera: Apidae) colony health and foraging ability.

    Science.gov (United States)

    Franklin, Michelle T; Winston, Mark L; Morandin, Lora A

    2004-04-01

    We conducted laboratory experiments to investigate the lethal and sublethal effects of clothianidin on bumble bee, Bombus impatiens Cresson, colony health and foraging ability. Bumble bee colonies were exposed to 6 ppb clothianidin, representing the highest residue levels found in field studies on pollen, and a higher dose of 36 ppb clothianidin in pollen. Clothianidin did not effect pollen consumption, newly emerged worker weights, amount of brood or the number of workers, males, and queens at either dose. The foraging ability of worker bees tested on an artificial array of complex flowers also did not differ among treatments. These results suggest that clothianidin residues found in seed-treated canola and possibly other crops will not adversely affect the health of bumble bee colonies or the foraging ability of workers.

  16. Glass forming ability of calcium aluminosilicate melts

    DEFF Research Database (Denmark)

    Moesgaard, Mette; Yue, Yuanzheng

    2011-01-01

    The glass forming ability (GFA) of two series of calcium aluminosilicate melts is studied by measuring their viscous behavior and crystallization tendency. The first series consists of five compositions on the joining line between the eutectic point of anorthite-wollastonite-tridymite and that of......The glass forming ability (GFA) of two series of calcium aluminosilicate melts is studied by measuring their viscous behavior and crystallization tendency. The first series consists of five compositions on the joining line between the eutectic point of anorthite......-wollastonite-tridymite and that of anorthite-wollastonite-gehlenite. The series includes the eutectic compositions as end members. The second series consists of five compositions on a line parallel to the joining line on the alumina rich side. In the present work, GFA is described in terms of glass stability, i.e., the ability of a glass...... to resist crystallization during reheating. In addition, the fragility index (m) is derived by fitting the viscosity data with the Avramov-Milchev equation. The results show that m is inversely proportional to the glass stability for the two series of melts, implying that m is an indirect measure of GFA...

  17. Functional Differences Between Placental Micro- and Macrovascular Endothelial Colony-Forming Cells

    Science.gov (United States)

    Solomon, Ioana; O’Reilly, Megan; Ionescu, Lavinia; Alphonse, Rajesh S.; Rajabali, Saima; Zhong, Shumei; Vadivel, Arul; Shelley, W. Chris; Yoder, Mervin C.

    2016-01-01

    Alterations in the development of the placental vasculature can lead to pregnancy complications, such as preeclampsia. Currently, the cause of preeclampsia is unknown, and there are no specific prevention or treatment strategies. Further insight into the placental vasculature may aid in identifying causal factors. Endothelial colony-forming cells (ECFCs) are a subset of endothelial progenitor cells capable of self-renewal and de novo vessel formation in vitro. We hypothesized that ECFCs exist in the micro- and macrovasculature of the normal, term human placenta. Human placentas were collected from term pregnancies delivered by cesarean section (n = 16). Placental micro- and macrovasculature was collected from the maternal and fetal side of the placenta, respectively, and ECFCs were isolated and characterized. ECFCs were CD31+, CD105+, CD144+, CD146+, CD14−, and CD45−, took up 1,1′-dioctadecyl-3,3,3′,3′-tetramethyl-indocarbocyanine perchlorate-labeled acetylated low-density lipoprotein, and bound Ulex europaeus agglutinin 1. In vitro, macrovascular ECFCs had a greater potential to generate high-proliferative colonies and formed more complex capillary-like networks on Matrigel compared with microvascular ECFCs. In contrast, in vivo assessment demonstrated that microvascular ECFCs had a greater potential to form vessels. Macrovascular ECFCs were of fetal origin, whereas microvascular ECFCs were of maternal origin. ECFCs exist in the micro- and macrovasculature of the normal, term human placenta. Although macrovascular ECFCs demonstrated greater vessel and colony-forming potency in vitro, this did not translate in vivo, where microvascular ECFCs exhibited a greater vessel-forming ability. These important findings contribute to the current understanding of normal placental vascular development and may aid in identifying factors involved in preeclampsia and other pregnancy complications. Significance This research confirms that resident endothelial colony-forming

  18. Increased numbers of spleen colony forming units in B cell deficient CBA/N mice

    International Nuclear Information System (INIS)

    Wiktor-Jedrzejczak, W.; Krupienicz, A.; Scher, I.

    1986-01-01

    The formation of exogenous and endogenous spleen colonies was studied in immune-defective mice expressing the CBA/N X-linked xid gene. Bone marrow and spleen cells of immune deficient mice formed increased numbers of eight-day exogenous spleen colonies when transferred to either normal or B cell deficient lethally irradiated recipients. Moreover, defective mice showed increased formation of five-day endogenous spleen colonies (derived from transient endogenous colony forming units; T-CFU) and of ten-day endogenous spleen colonies (derived from CFU-S). Among the possible mechanisms responsible for the observed effects, the most probable appears the one in which decreased numbers of B cell precursors stimulate stem cell pools through a feedback mechanism. (orig.) [de

  19. Responses of the Murine Myeloid Colony-Forming Cell to Ansamycin Antibiotics

    Science.gov (United States)

    Horoszewicz, Julius S.; Carter, William A.

    1974-01-01

    The in vitro susceptibility of murine myeloid colony-forming cells to the antiproliferative activities of three ansamycin antibiotics was determined. These cells were found to be 10- to 40-fold more susceptible than the corresponding human ones. PMID:4151701

  20. Competitive interactions between corals and turf algae depend on coral colony form.

    Science.gov (United States)

    Swierts, Thomas; Vermeij, Mark Ja

    2016-01-01

    Turf algae are becoming more abundant on coral reefs worldwide, but their effects on other benthic organisms remain poorly described. To describe the general characteristics of competitive interactions between corals and turf algae, we determined the occurrence and outcomes of coral-turf algal interactions among different coral growth forms (branching, upright, massive, encrusting, plating, and solitary) on a shallow reef in Vietnam. In total, the amount of turf algal interaction, i.e., the proportion of the coral boundary directly bordering turf algae, was quantified for 1,276 coral colonies belonging to 27 genera and the putative outcome of each interaction was noted. The amount of turf algal interaction and the outcome of these interactions differed predictably among the six growth forms. Encrusting corals interacted most often with turf algae, but also competed most successfully against turf algae. The opposite was observed for branching corals, which rarely interacted with turf algae and rarely won these competitive interactions. Including all other growth forms, a positive relationship was found between the amount of competitive interactions with neighboring turf algae and the percentage of such interaction won by the coral. This growth form dependent ability to outcompete turf algae was not only observed among coral species, but also among different growth forms in morphologically plastic coral genera (Acropora, Favia, Favites, Montastrea, Montipora, Porites) illustrating the general nature of this relationship.

  1. Isolation and characterization of human umbilical cord-derived endothelial colony-forming cells

    Science.gov (United States)

    Zhang, Hao; Tao, Yanling; Ren, Saisai; Liu, Haihui; Zhou, Hui; Hu, Jiangwei; Tang, Yongyong; Zhang, Bin; Chen, Hu

    2017-01-01

    Endothelial colony-forming cells (ECFCs) are a population of endothelial progenitor cells (EPCs) that display robust proliferative potential and vessel-forming capability. Previous studies have demonstrated that a limited number of ECFCs may be obtained from adult bone marrow, peripheral blood and umbilical cord (UC) blood. The present study describes an effective method for isolating ECFCs from human UC. The ECFCs derived from human UC displayed the full properties of EPCs. Analysis of the growth kinetics, cell cycle and colony-forming ability of the isolated human UC-ECFCs indicated that the cells demonstrated properties of stem cells, including relative stability and rapid proliferation in vitro. Gene expression of Fms related tyrosine kinase 1, kinase insert domain receptor, vascular endothelial cadherin, cluster of differentiation (CD)31, CD34, epidermal growth factor homology domains-2, von Willebrand factor and endothelial nitric oxide synthase was assessed by reverse transcription-polymerase chain reaction. The cells were positive for CD34, CD31, CD73, CD105 and vascular endothelial growth factor receptor-2, and negative for CD45, CD90 and human leukocyte antigen-antigen D related protein according to flow cytometry. 1,1′-dioctadecyl-3,3,3′,3′-tetra-methyl-indocarbocyanine perchlorate-labeled acetylated low-density lipoprotein and fluorescein isothiocyanate-Ulex europaeus-l were used to verify the identity of the UC-ECFCs. Matrigel was used to investigate tube formation capability. The results demonstrated that the reported technique is a valuable method for isolating human UC-ECFCs, which have potential for use in vascular regeneration. PMID:29067104

  2. Glass Forming Ability in Systems with Competing Orderings

    Science.gov (United States)

    Russo, John; Romano, Flavio; Tanaka, Hajime

    2018-04-01

    Some liquids, if cooled rapidly enough to avoid crystallization, can be frozen into a nonergodic glassy state. The tendency for a material to form a glass when quenched is called "glass-forming ability," and it is of key significance both fundamentally and for materials science applications. Here, we consider liquids with competing orderings, where an increase in the glass-forming ability is signaled by a depression of the melting temperature towards its minimum at triple or eutectic points. With simulations of two model systems where glass-forming ability can be tuned by an external parameter, we are able to interpolate between crystal-forming and glass-forming behavior. We find that the enhancement of the glass-forming ability is caused by an increase in the structural difference between liquid and crystal: stronger competition in orderings towards the melting point minimum makes a liquid structure more disordered (more complex). This increase in the liquid-crystal structure difference can be described by a single adimensional parameter, i.e., the interface energy cost scaled by the thermal energy, which we call the "thermodynamic interface penalty." Our finding may provide a general physical principle for not only controlling the glass-forming ability but also the emergence of glassy behavior of various systems with competing orderings, including orderings of structural, magnetic, electronic, charge, and dipolar origin.

  3. First report on the colony-forming freshwater ciliate Ophrydium versatile in an African river

    CSIR Research Space (South Africa)

    Oberholster, Paul J

    2010-04-01

    Full Text Available Ophrydium versatile (Müller 1786) Ehrenberg 1830 – a symbiotic ciliate that forms gelatinous colonies – is widely distributed in temperate lakes in Europe and America, but has not previously been recorded from rivers. In this paper we report...

  4. Heterogeneity within the spleen colony-forming cell population in rat bone marrow

    International Nuclear Information System (INIS)

    Martens, A.C.; van Bekkum, D.W.; Hagenbeek, A.

    1986-01-01

    The pluripotent hemopoietic stem cell (HSC) of the rat can be enumerated in a spleen colony assay (SCA) in rats as well as mice. After injection of rat bone marrow into lethally irradiated mice, macroscopically visible spleen colonies (CFU-S) are found from day 6 through 14, but the number varies on consecutive days. In normal bone marrow a constant ratio of day-8 to day-12 colony numbers is observed. However, this ratio is changed after in vivo treatment of rats with cyclophosphamide, as well as after in vitro treatment of rat bone marrow with cyclophosphamide derivatives. This indicates that the CFU-S that form colonies on day 8 react differently to this treatment than the CFU-S that form colonies on day 12, and suggests heterogeneity among the CFU-S population. Posttreatment regrowth of day-8 and day-12 CFU-S is characterized by differences in population-doubling times (Td = 0.85 days vs 1.65 days). Another argument in support of the postulate of heterogeneity within the rat CFU-S population is derived from the fact that (in contrast to normal rat spleen) the spleen of leukemic rats contains high numbers of CFU-S that show a ratio of day-8 to day-12 CFU-S of 4.5, which is different than that observed for a CFU-S population in normal bone marrow (a ratio of 2.4). It is concluded that, in rat hemopoiesis, two populations of spleen colony-forming cells can be distinguished using the rat-to-mouse SCA. This indicates that mouse and rat hemopoiesis are comparable in this respect and that heterogeneity in the stem cell compartment is a general phenomenon

  5. Effect of Fluoride Mouthrinse and Toothpaste on Number of Streptococcal Colony Forming Units of Dental Plaque

    Directory of Open Access Journals (Sweden)

    SE Jabbarifar

    2005-11-01

    Full Text Available Background: Frequent topical fluoride therapy through toothpaste, mouthrinse, professional gels and solutions causes decrease in incidence, pause and repair of dental caries in the enamel. These mechanisms are done through penetration of fluoride ions (F- and their replacement with hydroxyl ions (OH- of hydroxyappatite of enamel, interfere with microbial metabolism of dental plaque and bacteriostatic effect on some cariogenic bacterial strains such as streptococci. The aim of this study was to examine the effect of fluoride mouthrinse and toothpaste on the number of streptococcal colony forming units of dental plaque. Methods: 62 children with 6-7 years old were put in two groups. Samples of dental plaque from each group were collected both before and after use of the fluoride mouthrinse and or toothpaste. The samples were cultured on blood agar to find the number of streptococcal colony forming units (CFU. The mean colony forming unit was compared inter and intra groups before and after application of Fluoride products. Results: The streptococcal CFU of dental plaque before and after use of the mouthrinse and toothpaste respectively was (1240±1367, 1253±1341.5 and (551±716, 898±1151. Statistically, the streptococcal CFU in each group before and after use of the toothpaste and mouthrinse was significantly different. Conclusion: The findings of this study indicated that the fluoride toothpaste and mouthrinse reduce number of streptococcal colony forming units of dental plaque. Also this reduction was not depended on level of (F- Ions, sort of vehicle of fluoride and frequent application of the fluoride mouthrinse and toothpaste. Keywords: fluoride mouthrinse, fluoride toothpaste, colony forming unit (CFU, streptococcus

  6. Analysis of multidrug resistant group B streptococci with reduced penicillin susceptibility forming small, less hemolytic colonies.

    Directory of Open Access Journals (Sweden)

    Hirotsugu Banno

    Full Text Available Group B streptococci (GBS; Streptococcus agalactiae are the leading cause of neonatal invasive diseases and are also important pathogens for elderly adults. Until now, nearly all GBS with reduced penicillin susceptibility (PRGBS have shown β-hemolytic activity and grow on sheep blood agar. However, we have previously reported three PRGBS clinical isolates harboring a CylK deletion that form small less hemolytic colonies. In this study, we examined the causes of small, less hemolytic colony formation in these clinical isolates. Isogenic strains were sequenced to identify the mutation related to a small colony size. We identified a 276_277insG nucleic acid insertion in the thiamin pyrophosphokinase (tpk gene, resulting in premature termination at amino acid 103 in TPK, as a candidate mutation responsible for small colony formation. The recombinant strain Δtpk, which harbored the 276_277insG insertion in the tpk gene, showed small colony formation. The recombinant strain ΔcylK, which harbored the G379T substitution in cylK, showed a reduction in hemolytic activity. The phenotypes of both recombinant strains were complemented by the expression of intact TPK or CylK, respectively. Moreover, the use of Rapid ID 32 API and VITEK MS to identify strains as GBS was evaluated clinical isolates and recombinant strains. VITEK MS, but not Rapid ID 32 API, was able to accurately identify the strains as GBS. In conclusion, we determined that mutations in tpk and cylK caused small colonies and reduced hemolytic activity, respectively, and characterized the clinical isolates in detail.

  7. Heterogeneity of the radiosensitivity and origins of tissue macrophage colony-forming cells

    Energy Technology Data Exchange (ETDEWEB)

    Oghiso, Yoichi; Yamada, Yutaka (National Inst. of Radiological Sciences, Chiba (Japan))

    1992-12-01

    Previous studies suggest that the radiosensitivity and origin of tissue macrophage precursors differ from those of hemopoietic macrophage colony-forming units (CFU-Ms) committed to macrophage-lineage cells. We assessed the origins of tissue macrophage colony-forming cells (M-CFCs) in mice by comparing their kinetics and radiosensitivities in the normal steady state and under the conditions of bone marrow depletion by [sup 89]Sr-administration and/or splenectomy. The results indicate that the radiosensitive peritoneal M-CFCs elicited by thioglycollate are derived from bone marrow macrophage precursors; where as alveolar M-CFCs, which are radioresistant, are self-sustained locally and independent of hemopoietic macrophage precursors. In contrast, highly radiosensitive liver M-CFCs are probably derived from CFU-Ms that appear to be propagated in the spleen in association with hemopoietic responses. (author).

  8. Lymphocyte colony forming units and its application to the study of radiosensitivity

    International Nuclear Information System (INIS)

    Ma Xiangrui; Wang Tao; Wang Hongyun

    1991-07-01

    Kinetics and radiosensitivity of human lymphocytes were studied by the techniques of monolayer agar culture and liquid culture in vitro. In the experiments of lymphocyte kinetics, PHA was designated as a motogen for T lymphocyte. LPS, MEBC and BSA were chosen as mitogens for B lymphocyte. The data from thses experiments showed that under the alone or combination stimulation of LPS, MRBC and BSA, B lymphocytes developed to form colonies in agar culture (0.3%) with the same manner. The stimulation of LPS to B lymphocytes was most significant. By the day 6 after seeding, the numbers of colonies in agar culture were maximal. Whereas the numbers decreased significantly by the day 8. The number of T lymphocyte colonies increased with culture time within 12 days. The peak of 3 H-TdR incorporation into T lymphocytes in liquid culture occured at 5th day after seeding. The data above-mentioned demonstrated that the kinetics of lymphocytes cultured in two kinds of environments were different. The studies of the radiosensitivity of T lymphocytes showed that the decreasing in the number of colonies and rate of 3 H-TdR incorporation varied in different dose ranges. In the range of 0∼1.0 Gy, r = -0.96, D 0 value was 1.71 Gy for TL-CFC in agar culture, r = -.96, D 0 value was 4.34 Gy for the proliferation T lymphocytes in liquid culture. In the range of 1.0∼6.0 Gy, r were -0.99 and -0.98, the D 0 were 5.88 and 7.36 Gy respectively. The declining tendency in colonies formed by BL-CFC was the same as that of TL-CFC, r = -0.97, for the range of 0∼1.0 Gy, r = -0.97, for the range of 1.0∼3.0, the D 0 values were 1.35 and 4.36 Gy respectively. The results from these experiments shown that the colony technique was a good method for the study in radiosensitivity

  9. The effect of queen pheromone status on Varroa mite removal from honey bee colonies with different grooming ability.

    Science.gov (United States)

    Bahreini, Rassol; Currie, Robert W

    2015-07-01

    The objective of this study was to assess the effects of honey bees (Apis mellifera L.) with different grooming ability and queen pheromone status on mortality rates of Varroa mites (Varroa destructor Anderson and Trueman), mite damage, and mortality rates of honey bees. Twenty-four small queenless colonies containing either stock selected for high rates of mite removal (n = 12) or unselected stock (n = 12) were maintained under constant darkness at 5 °C. Colonies were randomly assigned to be treated with one of three queen pheromone status treatments: (1) caged, mated queen, (2) a synthetic queen mandibular pheromone lure (QMP), or (3) queenless with no queen substitute. The results showed overall mite mortality rate was greater in stock selected for grooming than in unselected stock. There was a short term transitory increase in bee mortality rates in selected stock when compared to unselected stock. The presence of queen pheromone from either caged, mated queens or QMP enhanced mite removal from clusters of bees relative to queenless colonies over short periods of time and increased the variation in mite mortality over time relative to colonies without queen pheromone, but did not affect the proportion of damaged mites. The effects of source of bees on mite damage varied with time but damage to mites was not reliably related to mite mortality. In conclusion, this study showed differential mite removal of different stocks was possible under low temperature. Queen status should be considered when designing experiments using bioassays for grooming response.

  10. Quantitative assay for the number of leukemic spleen colony forming unit in radiation-induced murine myeloid leukemia

    Energy Technology Data Exchange (ETDEWEB)

    Nara, N [Tokyo Medical and Dental Univ. (Japan). School of Medicine; Bessho, M

    1981-11-01

    In mice with myelogenous leukemia, leukemic spleen colony forming units were assayed quantitatively. When 5 x 10/sup 3/ - 2 x 10/sup 4/ leukemic cells were transplanted to other mice of the same strain, a rectilinear relationship (p < 0.01) was found between the number of the cells transplanted and that of the colonies formed on the surface of the spleen. From these results, the authors considered that myelogenous leukemia in mice is an adequate model for acute myelogenous leukemia in human adults, and that the quantitative assay of the leukemic colony forming units can be used for sensitivity tests of antileukemic agents.

  11. Identification and enrichment of colony-forming cells from the adult murine pituitary

    International Nuclear Information System (INIS)

    Lepore, D.A.; Roeszler, K.; Wagner, J.; Ross, S.A.; Bauer, K.; Thomas, P.Q.

    2005-01-01

    Stem and progenitor cells have been identified in many adult tissues including bone marrow, the central nervous system, and skin. While there is direct evidence to indicate the activity of a progenitor cell population in the pituitary gland, this putative subpopulation has not yet been identified. Herein we describe the isolation and characterization of a novel clonogenic cell type in the adult murine pituitary, which we have termed Pituitary Colony-Forming Cells (PCFCs). PCFCs constitute 0.2% of pituitary cells, and generate heterogeneous colonies from single cells. PCFCs exhibit variable proliferative potential, and may exceed 11 population doublings in 14 days. Enrichment of PCFCs to 61.5-fold with 100% recovery can be obtained through the active uptake of the fluorescent dipeptide, β-Ala-Lys-Nε-AMCA. PCFCs are mostly contained within the large, agranular subpopulation of AMCA + cells, and constitute 28% of this fraction, corresponding to 140.5-fold enrichment. Interestingly, the AMCA + population contains rare cells that are GH + or PRL + . GH + cells were also identified in PCFC single cell colonies, suggesting that PCFCs have the potential to differentiate into GH + cells. Together, these data show that the pituitary contains a rare clonogenic population which may correspond to the somatotrope/lactotrope progenitors suggested by previous experiments

  12. Glass-Forming Ability of Soda Lime Borate Liquids

    DEFF Research Database (Denmark)

    Zheng, Qiuju; Mauro, J.C.; Smedskjær, Morten Mattrup

    2012-01-01

    We investigate the composition dependence of glass-forming ability (GFA) of a series of iron-containing soda lime borate liquids by substituting Na2O for B2O3. We have characterized GFA by measuring the glass stability against crystallization using a differential scanning calorimeter (DSC......). The results show that the GFA decreases when substituting Na2O for B2O3. Moreover, we find that there is no direct link between the kinetic fragility and GFA for the soda lime borate series studied herein. We have also discovered and clarified a striking thermal history dependence of the glass stability...

  13. Colony shape as a genetic trait in the pattern-forming Bacillus mycoides

    Directory of Open Access Journals (Sweden)

    Pisaneschi Giuseppe

    2002-11-01

    Full Text Available Abstract Background Bacillus mycoides Flügge, a Gram-positive, non-motile soil bacterium assigned to Bacillus cereus group, grows on agar as chains of cells linked end to end, forming radial filaments curving clock- or counter-clockwise (SIN or DX morphotypes. The molecular mechanism causing asymmetric curving is not known: our working hypothesis considers regulation of filamentous growth as the prerequisite for these morphotypes. Results SIN and DX strains isolated from the environment were classified as B. mycoides by biochemical and molecular biology tests. Growth on agar of different hardness and nutrient concentration did not abolish colony patterns, nor was conversion between SIN and DX morphotypes ever noticed. A number of morphotype mutants, all originating from one SIN strain, were obtained. Some lost turn direction becoming fluffy, others became round and compact. All mutants lost wild type tight aggregation in liquid culture. Growth on agar was followed by microscopy, exploring the process of colony formation and details of cell divisions. A region of the dcw (division cell wall cluster, including ftsQ, ftsA, ftsZ and murC, was sequenced in DX and SIN strains as a basis for studying cell division. This confirmed the relatedness of DX and SIN strains to the B. cereus group. Conclusions DX and SIN asymmetric morphotypes stem from a close but not identical genomic context. Asymmetry is established early during growth on agar. Wild type bacilli construct mostly uninterrupted filaments with cells dividing at the free ends: they "walk" longer distances compared to mutants, where enhanced frequency of cell separation produces new growing edges resulting in round compact colonies.

  14. EFFICIENCY OF FORMING NUCLEUS COLONIES IN ORDER TO DECREASE POPULATION OF Varroa destructor (ANDRESON AND TRUEMAN, 2000 IN BEEHIVES

    Directory of Open Access Journals (Sweden)

    Zlatko Puškadija

    2003-12-01

    Full Text Available Forming of nucleus colonies is efficient method in growth control of Varroa destructor population. Its goal is to decrease parasite’s pressure on bee colony. The advantage of this bio-technical measurement lays in its implement during vegetation season which delays use of the chemical resources for Varroa destructor control population in beehives for the post major honey harvest period. Nucleus colonies were formed from approx. half of sealed brood (35.5 ± 5.8 dm² and average of 5915 ± 912 bees. Results showed that there were 37.2 ± 5.6% mites removed from parental colonies. Minimum was 30.8%, and maximum was 45.5%. Due to such relatively small efficiency, this method cannot be recommended as unique, but it can be effective if it is applied in the post spring's honey harvest period as a part of growth reduction strategy of Varroa destructor population in beehive.

  15. A new improved artificial bee colony algorithm for ship hull form optimization

    Science.gov (United States)

    Huang, Fuxin; Wang, Lijue; Yang, Chi

    2016-04-01

    The artificial bee colony (ABC) algorithm is a relatively new swarm intelligence-based optimization algorithm. Its simplicity of implementation, relatively few parameter settings and promising optimization capability make it widely used in different fields. However, it has problems of slow convergence due to its solution search equation. Here, a new solution search equation based on a combination of the elite solution pool and the block perturbation scheme is proposed to improve the performance of the algorithm. In addition, two different solution search equations are used by employed bees and onlooker bees to balance the exploration and exploitation of the algorithm. The developed algorithm is validated by a set of well-known numerical benchmark functions. It is then applied to optimize two ship hull forms with minimum resistance. The tested results show that the proposed new improved ABC algorithm can outperform the ABC algorithm in most of the tested problems.

  16. On the star-forming ability of Molecular Clouds

    Science.gov (United States)

    Anathpindika, S.; Burkert, A.; Kuiper, R.

    2018-02-01

    The star-forming ability of a molecular cloud depends on the fraction of gas it can cycle into the dense-phase. Consequently, one of the crucial questions in reconciling star formation in clouds is to understand the factors that control this process. While it is widely accepted that the variation in ambient conditions can alter significantly the ability of a cloud to spawn stars, the observed variation in the star-formation rate in nearby clouds that experience similar ambient conditions, presents an interesting question. In this work, we attempted to reconcile this variation within the paradigm of colliding flows. To this end we develop self-gravitating, hydrodynamic realizations of identical flows, but allowed to collide off-centre. Typical observational diagnostics such as the gas-velocity dispersion, the fraction of dense-gas, the column density distribution (N-PDF), the distribution of gas mass as a function of K-band extinction and the strength of compressional/solenoidal modes in the post-collision cloud were deduced for different choices of the impact parameter of collision. We find that a strongly sheared cloud is terribly inefficient in cycling gas into the dense phase and that such a cloud can possibly reconcile the sluggish nature of star formation reported for some clouds. Within the paradigm of cloud formation via colliding flows this is possible in case of flows colliding with a relatively large impact parameter. We conclude that compressional modes - though probably essential - are insufficient to ensure a relatively higher star-formation efficiency in a cloud.

  17. Diffusive boundary layers, photosynthesis, and respiration of the colony-forming plankton algae, Phaeocystis sp

    DEFF Research Database (Denmark)

    Ploug, Helle; Stolte, W.; Epping, E.H.G.

    1999-01-01

    H increased up to 0.4 units when measured in light at saturating intensities (>90 mu mol photons m(-2) s(-1)). The respiration in the dark was low, resulting in a 6% lowering in oxygen concentration and 0.04 units lowering in pH inside colonies, compared to the bulk water phase. Such colonies were net...... heterotrophic communities at light intensities up to 10 mu mol photons m(-2) s(-1). A week later, colonies were net heterotrophic at light intensities up to 80 mu mol photons m(-2) s(-1). The effective diffusion coefficient for oxygen in the gelatinous colonies was not significantly different from that in sea......Diffusive boundary layers, photosynthesis, and respiration in Phaeocystis colonies were studied by the use of microelectrodes for oxygen and pH during a bloom in the Barents Sea, 1993, and in the Marsdiep, Dutch North Sea, 1994. The oxygen microenvironment of a Phaeocystis colony with a mean...

  18. Matrix production and organization by endothelial colony forming cells in mechanically strained engineered tissue constructs.

    Directory of Open Access Journals (Sweden)

    Nicky de Jonge

    Full Text Available AIMS: Tissue engineering is an innovative method to restore cardiovascular tissue function by implanting either an in vitro cultured tissue or a degradable, mechanically functional scaffold that gradually transforms into a living neo-tissue by recruiting tissue forming cells at the site of implantation. Circulating endothelial colony forming cells (ECFCs are capable of differentiating into endothelial cells as well as a mesenchymal ECM-producing phenotype, undergoing Endothelial-to-Mesenchymal-transition (EndoMT. We investigated the potential of ECFCs to produce and organize ECM under the influence of static and cyclic mechanical strain, as well as stimulation with transforming growth factor β1 (TGFβ1. METHODS AND RESULTS: A fibrin-based 3D tissue model was used to simulate neo-tissue formation. Extracellular matrix organization was monitored using confocal laser-scanning microscopy. ECFCs produced collagen and also elastin, but did not form an organized matrix, except when cultured with TGFβ1 under static strain. Here, collagen was aligned more parallel to the strain direction, similar to Human Vena Saphena Cell-seeded controls. Priming ECFC with TGFβ1 before exposing them to strain led to more homogenous matrix production. CONCLUSIONS: Biochemical and mechanical cues can induce extracellular matrix formation by ECFCs in tissue models that mimic early tissue formation. Our findings suggest that priming with bioactives may be required to optimize neo-tissue development with ECFCs and has important consequences for the timing of stimuli applied to scaffold designs for both in vitro and in situ cardiovascular tissue engineering. The results obtained with ECFCs differ from those obtained with other cell sources, such as vena saphena-derived myofibroblasts, underlining the need for experimental models like ours to test novel cell sources for cardiovascular tissue engineering.

  19. Exercise increases the frequency of circulating hematopoietic progenitor cells, but reduces hematopoietic colony-forming capacity.

    Science.gov (United States)

    Kroepfl, Julia Maria; Pekovits, Karin; Stelzer, Ingeborg; Fuchs, Robert; Zelzer, Sieglinde; Hofmann, Peter; Sedlmayr, Peter; Dohr, Gottfried; Wallner-Liebmann, Sandra; Domej, Wolfgang; Mueller, Wolfram

    2012-11-01

    Circulating hematopoietic progenitor cells (CPCs) may be triggered by physical exercise and/or normobaric hypoxia from the bone marrow. The aim of the study was to investigate the influence of physical exercise and normobaric hypoxia on CPC number and functionality in the peripheral blood as well as the involvement of oxidative stress parameters as possibly active agents. Ten healthy male subjects (25.3±4.4 years) underwent a standardized cycle incremental exercise test protocol (40 W+20 W/min) under either normoxic (FiO2 ∼0.21) or hypoxic conditions (FiO2exercise. The number of CPCs in the peripheral blood was analyzed by flow cytometry (CD34/CD45-positive cells). The functionality of cells present was addressed by secondary colony-forming unit-granulocyte macrophage (CFU-GM) assays. To determine a possible correlation between the mobilization of CPCs and reactive oxygen species, parameters for oxidative stress such as malondialdehyde (MDA) and myeloperoxidase (MPO) were obtained. Data showed a significant increase of CPC release under normoxic as well as hypoxic conditions after 10 min of recovery (Pexercise (Pexercise, possibly due to the influence of increased oxidative stress levels.

  20. Tritiated thymidine and deoxycytidine suicide of mouse hemopoietic colony forming cells (CFC)

    International Nuclear Information System (INIS)

    Uyeki, E.M.; Wierzba, K.; Bisel, T.U.

    1981-01-01

    Significant enhancement of tritiated dCyd suicide occurred when unlabelled dThd was added to cultures of mouse monocytic colony-forming cells. Incorporation experiments supported the suicide experiments in that incorporation of tritiated dCyd into DNA was significantly increased. One hundred micromolar dCyd significantly reduced the radiotoxicity of 0.3 μCi of tritiated dThd; incorporation experiments indicated a dose-related reduction in the incorporation of tritiated dThd into DNA with the addition of 1-100 μM unlabelled dCyd. The addition of 1 μM aminopterin reversed the effect of 100 μM deoxycytidine; viz., incorporation of dThd into DNA was 90% of controls. Aminopterin had a similar effect on deoxyuridine reversal of tritiated dThd incorporation into DNA. Aminopterin had no effect on the reduction of tritiated dThd incorporation into DNA due to the addition of 100 μM unlabelled thymidine. Unlabelled ribonucleosides, Urd and Cyd, did not significantly affect the suicide pattern of tritiated dThd or dCyd when they were added to CFC cultures. Unlabelled deoxyribonucleosides, dThd or dCyd, did not significantly affect the suicide pattern of either tritiated Cyd or Urd when they were added to cultures containing tritiated ribonucleosides. Unlabelled Urd or Cyd was effective in reversing the suicide due to tritiated Urd or Cyd. (author)

  1. The genetics of colony form and function in Caribbean Acropora corals.

    Science.gov (United States)

    Hemond, Elizabeth M; Kaluziak, Stefan T; Vollmer, Steven V

    2014-12-17

    Colonial reef-building corals have evolved a broad spectrum of colony morphologies based on coordinated asexual reproduction of polyps on a secreted calcium carbonate skeleton. Though cnidarians have been shown to possess and use similar developmental genes to bilaterians during larval development and polyp formation, little is known about genetic regulation of colony morphology in hard corals. We used RNA-seq to evaluate transcriptomic differences between functionally distinct regions of the coral (apical branch tips and branch bases) in two species of Caribbean Acropora, the staghorn coral, A. cervicornis, and the elkhorn coral, A. palmata. Transcriptome-wide gene profiles differed significantly between different parts of the coral colony as well as between species. Genes showing differential expression between branch tips and bases were involved in developmental signaling pathways, such as Wnt, Notch, and BMP, as well as pH regulation, ion transport, extracellular matrix production and other processes. Differences both within colonies and between species identify a relatively small number of genes that may contribute to the distinct "staghorn" versus "elkhorn" morphologies of these two sister species. The large number of differentially expressed genes supports a strong division of labor between coral branch tips and branch bases. Genes involved in growth of mature Acropora colonies include the classical signaling pathways associated with development of cnidarian larvae and polyps as well as morphological determination in higher metazoans.

  2. Reduced proliferation of endothelial colony-forming cells in unprovoked venous thromboembolic disease as a consequence of endothelial dysfunction

    Science.gov (United States)

    Hernandez-Lopez, Rubicel; Chavez-Gonzalez, Antonieta; Torres-Barrera, Patricia; Moreno-Lorenzana, Dafne; Lopez-DiazGuerrero, Norma; Santiago-German, David; Isordia-Salas, Irma; Smadja, David; C. Yoder, Mervin; Majluf-Cruz, Abraham

    2017-01-01

    Background Venous thromboembolic disease (VTD) is a public health problem. We recently reported that endothelial colony-forming cells (ECFCs) derived from endothelial cells (EC) (ECFC-ECs) from patients with VTD have a dysfunctional state. For this study, we proposed that a dysfunctional status of these cells generates a reduction of its proliferative ability, which is also associated with senescence and reactive oxygen species (ROS). Methods and results Human mononuclear cells (MNCs) were obtained from peripheral blood from 40 healthy human volunteers (controls) and 50 patients with VTD matched by age (20−50 years) and sex to obtain ECFCs. We assayed their proliferative ability with plasma of patients and controls and supernatants of cultures from ECFC-ECs, senescence-associated β-galactosidase (SA-β-gal), ROS, and expression of ephrin-B2/Eph-B4 receptor. Compared with cells from controls, cells from VTD patients showed an 8-fold increase of ECFCs that emerged 1 week earlier, reduced proliferation at long term (39%) and, in passages 4 and 10, a highly senescent rate (30±1.05% vs. 91.3±15.07%, respectively) with an increase of ROS and impaired expression of ephrin-B2/Eph-4 genes. Proliferation potential of cells from VTD patients was reduced in endothelial medium [1.4±0.22 doubling population (DP)], control plasma (1.18±0.31 DP), or plasma from VTD patients (1.65±0.27 DP). Conclusions As compared with controls, ECFC-ECs from individuals with VTD have higher oxidative stress, proliferation stress, cellular senescence, and low proliferative potential. These findings suggest that patients with a history of VTD are ECFC-ECs dysfunctional that could be associated to permanent risk for new thrombotic events. PMID:28910333

  3. Substitution of Soybean Meal and Cornmeal to Moisture, PH, Bacterial Colony Forming and Shelf Life of Rejected Duck Meatballs

    OpenAIRE

    Deni, Novia; Juliyarsi, Indri; Melia, S; Vermalida, W.A

    2013-01-01

    This study aimed to determine the effect of substitution of soybean meal with cornmeal to moisture, pH, bacterial colony forming and the shelf life of rejected duck meatballs. This research material using duck meat Coast (Indian Runner) salvage as much as 4000 grams were obtained from the Livestock Anduring Padang and soybean meal with Mungbean trademarks and cornmeal with cornstarch trademarks respectively of 600 grams were obtained at Raya Padang market. The research method used was experim...

  4. Effect of adrenalectomy on recipients of allogeneic lymphocytes on inactivation of endogenous colony-forming cells in mice

    International Nuclear Information System (INIS)

    Semenkov, V.F.

    1985-01-01

    This paper presents a study of the killer functions of lymph node cells directed against endogenous colony-forming cells in adrenalectomized recipients in a genetic system with one-way incompatibility: parental line - F 1 hybrid. Mice were irradiated with Co 60 gamma rays on the EGO-2 apparatus with dose rate from 200 to 250 R/min. The results were subjected to statistical analysis by Student's test. It can be tentatively suggested that the killer action of T lymphocytes on endogenous colonies was intensified in adrenal-ectomized recipients with endogenous hypocorticism, as a result of cooperation with the cortisol-sensitive subpopulation of T helper cells, of a change in the properties of the antigen-recognizing receptors, or an increase in the sensitivity of target cells to the killer action of T lymphocytes

  5. Career Adapt-Abilities Scale--Netherlands Form: Psychometric Properties and Relationships to Ability, Personality, and Regulatory Focus

    Science.gov (United States)

    van Vianen, Annelies E. M.; Klehe, Ute-Christine; Koen, Jessie; Dries, Nicky

    2012-01-01

    The Career Adapt-Abilities Scale (CAAS)--Netherlands Form consists of four scales, each with six items, which measure concern, control, curiosity, and confidence as psychosocial resources for managing occupational transitions, developmental tasks, and work traumas. Internal consistency estimates for the subscale and total scores ranged from…

  6. Settler colonial power and the American Indian sovereignty movement: forms of domination, strategies of transformation.

    Science.gov (United States)

    Steinman, Erich

    2012-01-01

    The article extends the multi-institutional model of power and change through an analysis of the American Indian Sovereignty Movement. Drawing upon cultural models of the state, and articulating institutionalist conceptions of political opportunities and resources, the analysis demonstrates that this framework can be applied to challenges addressing the state as well as nonstate fields. The rational-legal diminishment of tribal rights, bureaucratic paternalism, commonsense views of tribes as racial/ethnic minorities, and the binary construction of American and Indian as oppositional identities diminished the appeal of "contentious" political action. Instead, to establish tribes' status as sovereign nations, tribal leaders aggressively enacted infrastructural power, transposed favorable legal rulings across social fields to legitimize sovereignty discourses, and promoted a pragmatic coexistence with state and local governments. Identifying the United States as a settler colonial society, the study suggests that a decolonizing framework is more apt than racial/ethnicity approaches in conceptualizing the struggle of American Indians.

  7. A stimulator of proliferation of spleen colony-forming cells (CFU-S) in the bone marrow of irradiated rats

    Energy Technology Data Exchange (ETDEWEB)

    Ivanovic, Z.; Milenkovic, P.; Stojanovic, N.; Lukic, M.; Kataranovski, M.

    1993-07-01

    The presence and activity of a spleen colony - forming cell (CFU-S) proliferation stimulator was investigated in rat bone marrow after irradiation. The dose dependent increase in cytosine arabinoside induced cell dealth of normal mouse bone marrow. The results demonstrate the existence of a CFU-S proliferation stimulator in rat bone marrow similar to that originally found as a macrophage product in regenarating mouse bone marrow. The CFU-S proliferation stimulator activity was not associated with the presence of interleukin - 1,2, or 6 like activities in the material tested.

  8. 1. modification of the proliferative capacity of transplanted bone marrow colony forming units by changes in the host environment

    International Nuclear Information System (INIS)

    Beran, M.; Tribukait, B.

    1974-01-01

    Regulation of the proliferation of transplanted colony forming units (CFUs) was investigated in lethally irradiated mice, pretreated by methods known to accelerate hemopoietic recovery after sublethal irradiation. Prospective recipients were exposed to either hypoxia, vinblastine or priming irradiation and at different intervals thereafter lethally irradiated and transplanted with bone marrow. Repopulation of CFUs was determined by counting the number of splenic colonies in primary recipients or by retransplantation. Regeneration of grafted CFUs was greatly accelerated and their self-renewal capacity increased in mice grafted within 2 days after hypoxia. Also the number of splenic colonies formed by grafted syngeneic CFUs as well as by C57B1 parent CFUs growing in BC3F1 hosts was significantly increased. The effect was not dependent on the seeding efficiency of CFUs and apparently resulted from hypoxia induced changes in the hosts' physiological environment. Proliferative capacity of grafted CFUs increased remarkably in hosts receiving vinblastine 2 or 4 days prior to irradiation. Priming irradiation given 6 days before main irradiation accelerated, given 2 days before impaired regeneration of CFUs. The increased rate of regeneration was not related to the cellularity of hemopoietic organs at the time of transplantation. The growth of CFUs in diffusion chambers implanted into posthypoxic mice was only slightly improved which does indicate that the accelerated regeneration of CFUs in posthypoxic mice is mainly due to the changes in the hemopoietic microenvironment. A short conditioning of transplanted CFUs by host factor(s) was sufficient to improve regeneration. The results might suggest that the speed of hemopoietic regeneration depends on the number of CFUs being induced to proliferate shortly after irradiation, rather than on the absolute numbers of CFUs available to the organism. (author)

  9. Genetic control of the honey bee (Apis mellifera) dance language: segregating dance forms in a backcrossed colony.

    Science.gov (United States)

    Johnson, R N; Oldroyd, B P; Barron, A B; Crozier, R H

    2002-01-01

    We studied the genetic control of the dance dialects that exist in the different subspecies of honey bees (Apis mellifera) by observing the variation in dance form observed in a backcross between two lines that showed widely different dance dialects. To do this we generated the reciprocal of the cross performed by Rinderer and Beaman (1995), thus producing phenotypic segregation of dance forms within a single colony rather than between colonies. Our results are consistent with Rinderer and Beaman (1995) in that inheritance of the transition point from round dancing --> waggle dancing is consistent with control by a single locus with more than one allele. That is, we found one dance type to be dominant in the F(1), and observed a 1:1 segregation of dance in a backcross involving the F(1) and the recessive parent. However, we found some minor differences in dance dialect inheritance, with the most significant being an apparent reversal of dominance between our cross (for us "black" is the dominant dialect) and that of Rinderer and Beaman (1995) (they report "yellow" to be the dominant dialect). We also found that our black bees do not perform a distinct sickle dance, whereas the black bees used by Rinderer and Beaman (1995) did perform such a dance. However, our difference in dominance need not contradict the results of Rinderer and Beaman (1995), as there is no evidence that body color and dominance for dance dialect are linked.

  10. Fabrication of corneal epithelial cell sheets maintaining colony-forming cells without feeder cells by oxygen-controlled method.

    Science.gov (United States)

    Nakajima, Ryota; Takeda, Shizu

    2014-01-01

    The use of murine 3T3 feeder cells needs to be avoided when fabricating corneal epithelial cell sheets for use in treating ocular surface diseases. However, the expression level of the epithelial stem/progenitor cell marker, p63, is down-regulated in feeder-free culture systems. In this study, in order to fabricate corneal epithelial cell sheets that maintain colony-forming cells without using any feeder cells, we investigated the use of an oxygen-controlled method that was developed previously to fabricate cell sheets efficiently. Rabbit limbal epithelial cells were cultured under hypoxia (1-10% O2) and under normoxia during stratification after reaching confluence. Multilayered corneal epithelial cell sheets were fabricated using an oxygen-controlled method, and immunofluorescence analysis showed that cytokeratin 3 and p63 was expressed in appropriate localization in the cell sheets. The colony-forming efficiency of the cell sheets fabricated by the oxygen-controlled method without feeder cells was significantly higher than that of cell sheets fabricated under 20% O2 without feeder cells. These results indicate that the oxygen-controlled method has the potential to achieve a feeder-free culture system for fabricating corneal epithelial cell sheets for corneal regeneration. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Production of humoral factors that stimulate spleen colony-forming units in mice irradiated with moderate doses of X rays

    International Nuclear Information System (INIS)

    Grande, T.; Gonzalez, J.; Tejero, C.; Maganto, G.; Bueren, J.A.

    1990-01-01

    The production of humoral factors that stimulate spleen colony-forming units (CFU-S) has been studied in irradiated mice using an in vivo diffusion chamber assay. The experiments show that a significant release of factors that stimulate CFU-S takes place in the first few days after irradiation with moderate doses of 1.5 or 5 Gy. In contrast, the release of significant amounts of these humoral factors was not seen in animals irradiated with either low (0.75 Gy) or high (10 Gy) doses of X rays. The correlation observed between the production of factors that stimulate the CFU-S and the hemopoietic regeneration kinetics of the irradiated mice suggests that these factors represent part of the physiological regulators controlling the proliferation of CFU-S

  12. Capacity of bone marrow colony forming unit-fibroblasts in vitro from mice with combined radiation-burn injury

    International Nuclear Information System (INIS)

    Chen Xinghua; Luo Chengji; Guo Chaohua; Wang Ping

    1999-01-01

    Objective: To investigate the capacity of bone marrow colony forming unit-fibroblasts (CFU-F) from mice with combined radiation-burn injury. Methods: Mice were treated with 5.0 Gy γ-ray radiation alone, 15% total body surface area (TBSA) III degree burn alone or combined radiation-burn. The numbers of CFU-Fs were assayed by Dexter's method. Results: The numbers of CFU-Fs from mice with radiation and combined radiation-burn injury were significantly decreased, compared with those of controls and mice with burn injury alone (P<0.05-0.01). conclusion: The results reveal that the repairing process of bone marrow stromal cells from mice with radiation injury and combined radiation-burn injury is slow, and the combined radiation-burn injury inflicted on the stromal cells possesses the characteristic of radiation injury

  13. Colonial Institutions

    DEFF Research Database (Denmark)

    McAtackney, Laura; Palmer, Russell

    2016-01-01

    and the USA which reveal that the study of colonial institutions should not be limited to the functional life of these institutions—or solely those that take the form of monumental architecture—but should include the long shadow of “imperial debris” (Stoler 2008) and immaterial institutions....

  14. Glass Forming Ability of Amorphous Drugs Investigated by Continuous Cooling and Isothermal Transformation.

    Science.gov (United States)

    Blaabjerg, Lasse I; Lindenberg, Eleanor; Löbmann, Korbinian; Grohganz, Holger; Rades, Thomas

    2016-09-06

    The aim of this study was to investigate the glass forming ability of 12 different drugs by the determination of continuous cooling and isothermal transformation diagrams in order to elucidate if an inherent differentiation between the drugs with respect to their the glass forming ability can be made. Continuous-cooling-transformation (CCT) and time-temperature-transformation (TTT) diagrams of the drugs were developed in order to predict the critical cooling rate necessary to convert the drug from the melt into an amorphous form. While TTT diagrams overestimated the actual critical cooling rate, they allowed an inherent differentiation of glass forming ability for the investigated drugs into drugs that are extremely difficult to amorphize (>750 °C/min), drugs that require modest cooling rates (>10 °C/min), and drugs that can be made amorphous even at very slow cooling rates (>2 °C/min). Thus, the glass forming ability can be predicted by the use of TTT diagrams. In contrast to TTT diagrams, CCT diagrams may not be suitable for small organic molecules due to poor separation of exothermic events, which makes it difficult to determine the zone of recrystallization. In conclusion, this study shows that glass forming ability of drugs can be predicted by TTT diagrams.

  15. Mini Seminar on Form Filling Ability of Self-Compacting Concrete

    DEFF Research Database (Denmark)

    Thrane, Lars Nyholm

    2005-01-01

    The Nordic mini-seminar “Form Filling Ability of Self-Compacting Concrete” took place on 3-4 November 2003 at the Danish Technological Institute in Taastrup, Denmark. The mini-seminar gathered 12 participants from Finland, Sweden, Norway and Denmark. The objective was to present and discuss recent...... developments of Self-Compacting Concrete in the Nordic countries. In general, the seminar included results and observations on the effect of fresh concrete behaviour, casting technique, and organisation on site on the filling ability, passing ability, and surface quality. The seminar had participants from...

  16. Precursors (pre-CFCmulti) of multilineage hemopoietic colony-forming cells quantitated in vitro. Uniqueness of IL-1 requirement, partial separation from pluripotential colony-forming cells, and correlation with long term reconstituting cells in vivo

    International Nuclear Information System (INIS)

    Iscove, N.N.; Yan, X.Q.

    1990-01-01

    Pluripotential colony-forming cells (CFCmulti) from mouse marrow can expand significantly in number during 4 days of suspension culture with IL-1 and IL-3. In this study, the cells (pre-CFCmulti) which originate this response are characterized in terms of their frequency, progeny number, factor requirements, buoyant density, and extent of restoration following marrow transplantation. Parallel measurements of both CFCmulti and cells providing long term marrow reconstitution in vivo allowed direct comparisons to be made with pre-CFCmulti. The proliferative response of pre-CFCmulti was found to depend uniquely on the combination of IL-1 and IL-3, and neither of these regulators was replaceable by any of IL-4, IL-6, IL-7, GM-CSF, G-CSF, M-CSF or LIF. After separation on density gradients, pre-CFCmulti were recovered in fractions of lower density than most of the CFCmulti, but in the same fractions that contained most of the in vivo reconstituting cells. After irradiation and marrow transplantation, marrow CFCmulti were restored to near normal levels, while both pre-CFCmulti as well as reconstituting stem cells remained profoundly depressed. These results show pre-CFCmulti to be distinct from most CFCmulti and to represent the closest approach to quantitative detection of reconstituting stem cells so far achieved in vitro

  17. Density and glass forming ability in amorphous atomic alloys: The role of the particle softness

    International Nuclear Information System (INIS)

    Douglass, Ian; Hudson, Toby; Harrowell, Peter

    2016-01-01

    A key property of glass forming alloys, the anomalously small volume difference with respect to the crystal, is shown to arise as a direct consequence of the soft repulsive potentials between metals. This feature of the inter-atomic potential is demonstrated to be responsible for a significant component of the glass forming ability of alloys due to the decrease in the enthalpy of fusion and the associated depression of the freezing point.

  18. Density and glass forming ability in amorphous atomic alloys: The role of the particle softness

    Energy Technology Data Exchange (ETDEWEB)

    Douglass, Ian; Hudson, Toby; Harrowell, Peter [School of Chemistry, University of Sydney, Sydney, NSW (Australia)

    2016-04-14

    A key property of glass forming alloys, the anomalously small volume difference with respect to the crystal, is shown to arise as a direct consequence of the soft repulsive potentials between metals. This feature of the inter-atomic potential is demonstrated to be responsible for a significant component of the glass forming ability of alloys due to the decrease in the enthalpy of fusion and the associated depression of the freezing point.

  19. Isolation of endothelial colony-forming cells from blood samples collected from the jugular and cephalic veins of healthy adult horses.

    Science.gov (United States)

    Sharpe, Ashley N; Seeto, Wen J; Winter, Randolph L; Zhong, Qiao; Lipke, Elizabeth A; Wooldridge, Anne A

    2016-10-01

    OBJECTIVE To evaluate optimal isolation of endothelial colony-forming cells (ECFCs) from peripheral blood of horses. SAMPLE Jugular and cephalic venous blood samples from 17 adult horses. PROCEDURES Each blood sample was divided; isolation was performed with whole blood adherence (WBA) and density gradient centrifugation (DGC). Isolated cells were characterized by uptake of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate-labeled acetylated low-density lipoprotein (DiI-Ac-LDL), vascular tubule formation, and expression of endothelial (CD34, CD105, vascular endothelial growth factor receptor-2, and von Willebrand factor) and hematopoietic (CD14) cell markers by use of indirect immunofluorescence assay (IFA) and flow cytometry. RESULTS Colonies with cobblestone morphology were isolated from 15 of 17 horses. Blood collected from the cephalic vein yielded colonies significantly more often (14/17 horses) than did blood collected from the jugular vein (8/17 horses). Of 14 cephalic blood samples with colonies, 13 were obtained with DGC and 8 with WBA. Of 8 jugular blood samples with colonies, 8 were obtained with DGC and 4 with WBA. Colony frequency (colonies per milliliter of blood) was significantly higher for cephalic blood samples and samples isolated with DGC. Cells formed vascular tubules, had uptake of DiI-Ac-LDL, and expressed endothelial markers by use of IFA and flow cytometry, which confirmed their identity as ECFCs. CONCLUSIONS AND CLINICAL RELEVANCE Maximum yield of ECFCs was obtained for blood samples collected from both the jugular and cephalic veins and use of DGC to isolate cells. Consistent yield of ECFCs from peripheral blood of horses will enable studies to evaluate diagnostic and therapeutic uses.

  20. Resource function of conceptual and metacognitive abilities in adolescents with different forms of dysontogenesis.

    Directory of Open Access Journals (Sweden)

    Kholodnaya, M.

    2015-07-01

    Full Text Available This study investigated the level of conceptual and metacognitive abilities and their interaction in adolescents with different forms of dysontogenesis. The total sample (N= 173 included four groups of young adolescents (11-12 years old: with normal development, with infantile cerebral palsy (CP, with attention deficit hyperactivity disorder (ADHD, and with delayed intellectual development (DID. We measured the adolescents’ performance on tests of conceptual abilities (the use of categories at different grades of generalization, the discovery of abstract meaning and implicit connections between concepts and metacognitive abilities (attention selectivity, as measured by Mtinsterberg’s test and the understanding of hidden pictures, and attention organization, as measured by indices of cognitive styles. The results showed, first, that in comparison with normal adolescents, the adolescents with CP and ADHD had a deficit of metacognitive abilities, but they did not differ in rates of conceptual abilities. As for adolescents with DID, even though they had lower rates of conceptual abilities and attention selectivity, they did not differ from the “norm” group on some indices of attention organization. Second, a tendency for the disintegration of conceptual and metacognitive abilities (as measured by correlation and factor analysis was most clearly seen in the adolescents with ADHD and DID. The adolescents with CP and ADHD had conceptual (categorial and generative abilities as a mental resource, and the adolescents with DID had metacognitive abilities as a mental resource. The resource function of conceptual and metacognitive abilities was determined not only by their level but also by the extent of their interaction (integration.

  1. Glass forming ability of amorphous drugs investigated by continuous cooling- and isothermal transformation

    DEFF Research Database (Denmark)

    Blaabjerg, Lasse Ingerslev; Lindenberg, Eleanor; Löbmann, Korbinian

    2016-01-01

    /min). Thus, the glass forming ability can be predicted by the use of TTT diagrams. In contrast to TTT diagrams, CCT diagrams may not be suitable for small organic molecules due to poor separation of exothermic events, which makes it difficult to determine the zone of recrystallization. In conclusion...

  2. Career Adapt-Abilities Scale-Belgium Form: psychometric characteristics and construct validity

    NARCIS (Netherlands)

    Dries, N.; van Esbroeck, R.; van Vianen, A.E.M.; de Cooman, R.; Pepermans, R.

    2012-01-01

    The Dutch version of the Career Adapt-Abilities Scale-Belgium Form (CAAS-Belgium) consists of four scales, each with six items, which measure concern, control, curiosity, and confidence as psychosocial resources for managing occupational transitions, developmental tasks, and work traumas. A pilot

  3. Field Dependence/Independence in College Nonmusic Majors and Their Ability to Discern Form in Music.

    Science.gov (United States)

    Ellis, Mark C.; McCoy, Clair W.

    1990-01-01

    Measures the effects of cognitive-style field dependence/field independence on students' ability to discern form in music. Applies tests to 119 nonmusic majors enrolled in an introductory music course. Finds field-independent subjects scored significantly higher than field-dependent subjects. Identifies variables affecting learning for both…

  4. Gene knockdown of CENPA reduces sphere forming ability and stemness of glioblastoma initiating cells

    Directory of Open Access Journals (Sweden)

    Jinan Behnan

    2016-09-01

    Knockdown of CENPA reduced sphere forming ability, proliferation and cell viability of GICs. We also detected significant reduction in the expression of stemness marker SOX2 and the proliferation marker Ki67. These results indicate that CENPA might represent a promising therapeutic target for GBM treatment.

  5. [Apatite-forming ability of pure titanium implant after micro-arc oxidation treatment].

    Science.gov (United States)

    Tian, Zhihui; Zhang, Yu; Wang, Lichao; Nan, Kaihui

    2013-10-01

    To investigate the apatite forming ability of pure titanium implant after micro-arc oxidation treatment in simulated body fluid (SBF) and obtain implants with calcium phosphate (Ca-P) layers. The implants were immersed in (SBF) after micro-arc oxidation treatment for different time lengths, and their apatite forming ability and the morphology and constituents of the Ca-P layers formed on the sample surface were analyzed using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and energy dispersive electron probe. After immersion in SBF, large quantities of Ca-P layers were induced on the surface of the samples. The Ca-P layers were composed of octacalcium phosphate and carbonated hydroxyapatite, and the crystals showed a plate-like morphology with an oriented growth. The implants with micro-arc oxidation treatment show good apatite forming ability on the surface with rich calcium and phosphorus elements. The formed layers are composed of bone-like apatite including octacalcium phosphate and carbonated hydroxyapatite.

  6. The Transcription Factor Nrf2 Protects Angiogenic Capacity of Endothelial Colony-Forming Cells in High-Oxygen Radical Stress Conditions

    NARCIS (Netherlands)

    Gremmels, Hendrik; De Jong, Olivier G.; Hazenbrink, Diënty H.; Fledderus, Joost O.; Verhaar, Marianne C.

    2017-01-01

    Background. Endothelial colony forming cells (ECFCs) have shown a promise in tissue engineering of vascular constructs, where they act as endothelial progenitor cells. After implantation, ECFCs are likely to be subjected to elevated reactive oxygen species (ROS). The transcription factor Nrf2

  7. Optimization of the culturing conditions of human umbilical cord blood-derived endothelial colony-forming cells under xeno-free conditions applying a transcriptomic approach

    NARCIS (Netherlands)

    Zeisberger, Steffen M.; Zoller, Stefan; Riegel, Mariluce; Chen, Shuhua; Krenning, Guido; Harmsen, Martin C.; Sachinidis, Agapios; Zisch, Andreas H.

    Establishment of fetal bovine serum (FBS)-free cell culture conditions is essential for transplantation therapies. Blood-derived endothelial colony-forming cells (ECFCs) are potential candidates for regenerative medicine applications. ECFCs were isolated from term umbilical cord blood units and

  8. Glass forming ability: Miedema approach to (Zr, Ti, Hf)-(Cu, Ni) binary and ternary alloys

    Energy Technology Data Exchange (ETDEWEB)

    Basu, Joysurya [Department of Chemical, Materials and Biomolecular Engineering, 191 Auditorium Road, University of Connecticut, Storrs 06269, CT (United States)], E-mail: jbasu@engr.uconn.edu; Murty, B.S. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Ranganathan, S. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India)

    2008-10-06

    Miedema's approach has been useful in determining the glass forming composition range for a particular alloy system. The concept of mixing enthalpy and mismatch entropy can be used in order to quantify Inoue's criteria of bulk metallic glass formation. In the present study, glass forming composition range has been determined for different binary and ternary (Zr, Ti, Hf)-(Cu, Ni) alloys based on the mixing enthalpy and mismatch entropy calculations. Though copper and nickel appear next to each other in the periodic table, the glass forming ability of the copper and nickel bearing alloys is different. Thermodynamic analysis reveals that the glass forming behaviour of Zr and Hf is similar, whereas it is different from that of Ti. The smaller atomic size of Ti and the difference in the heat of mixing of Ti, Zr, Hf with Cu and Ni leads to the observed changes in the glass forming behaviour. Enthalpy contour plots can be used to distinguish the glass forming compositions on the basis of the increasing negative enthalpy of the composition. This method reveals the high glass forming ability of binary Zr-Cu, Hf-Cu, Hf-Ni systems over a narrow composition range.

  9. Increase in colony-forming efficiency in soft agar of thymus cells from radiation-induced thymomas of NIH Swiss mice

    Energy Technology Data Exchange (ETDEWEB)

    Mori, Nobuko; Takamori, Yasuhiko; Hori, Yasuharu [Radiation Center of Osaka Prefecture, Sakai (Japan)

    1982-03-01

    Colony-forming efficiency in soft agar of radiation-induced thymoma in NIH Swiss mice was determined in the presence of cultured medium of reticulo-epitherial cells from normal thymus of NIH Swiss mouse as conditioned medium. A similar experiment was done with thymomas spontaneously developed in AKR mice. Most of colonies developed in soft agar were not composed of thymic lymphoma cells, but of macrophage-like cells. The ratio of the number of colonies to that of the seeded cells significantly increased in thymomas comparing with that in normal thymus. This result corresponded with the increased number of macrophages in thymoma, as determined by counting phagocytic cells of adherent cells.

  10. The hematopoietic chemokine CXCL12 promotes integration of human endothelial colony forming cell-derived cells into immature vessel networks.

    Science.gov (United States)

    Newey, Sarah E; Tsaknakis, Grigorios; Khoo, Cheen P; Athanassopoulos, Thanassi; Camicia, Rosalba; Zhang, Youyi; Grabowska, Rita; Harris, Adrian L; Roubelakis, Maria G; Watt, Suzanne M

    2014-11-15

    Proangiogenic factors, vascular endothelial growth factor (VEGF), and fibroblast growth factor-2 (FGF-2) prime endothelial cells to respond to "hematopoietic" chemokines and cytokines by inducing/upregulating expression of the respective chemokine/cytokine receptors. Coculture of human endothelial colony forming cell (ECFC)-derived cells with human stromal cells in the presence of VEGF and FGF-2 for 14 days resulted in upregulation of the "hematopoietic" chemokine CXCL12 and its CXCR4 receptor by day 3 of coculture. Chronic exposure to the CXCR4 antagonist AMD3100 in this vasculo/angiogenesis assay significantly reduced vascular tubule formation, an observation recapitulated by delayed AMD3100 addition. While AMD3100 did not affect ECFC-derived cell proliferation, it did demonstrate a dual action. First, over the later stages of the 14-day cocultures, AMD3100 delayed tubule organization into maturing vessel networks, resulting in enhanced endothelial cell retraction and loss of complexity as defined by live cell imaging. Second, at earlier stages of cocultures, we observed that AMD3100 significantly inhibited the integration of exogenous ECFC-derived cells into established, but immature, vascular networks. Comparative proteome profiler array analyses of ECFC-derived cells treated with AMD3100 identified changes in expression of potential candidate molecules involved in adhesion and/or migration. Blocking antibodies to CD31, but not CD146 or CD166, reduced the ECFC-derived cell integration into these extant vascular networks. Thus, CXCL12 plays a key role not only in endothelial cell sensing and guidance, but also in promoting the integration of ECFC-derived cells into developing vascular networks.

  11. Thermal sensitivity and thermally enhanced radiosensitivity of murine bone marrow granulocyte-macrophage colony-forming units (CFU-GM)

    International Nuclear Information System (INIS)

    Yoshida, Hiroshi

    1994-01-01

    This study was to evaluate thermal response of granulocyte-macrophage colony-forming unit (CFU-GM) in vitro and to investigate the difference of thermally enhanced radiosensitivity on cell survivals of CFU-GM between in vitro and in vivo. In in vitro heating exposure, bone marrow suspensions, obtained from mouse femora or tibiae, were incubated; and in vivo heating exposure, the lower half-body of mice were immersed in a circulating hot water bath. For irradiation schedules, cell suspensions were irradiated in vitro or in vivo (whole-body irradiation). Thermal sensitivity curve, obtained by in vivo heating exposure, showed a shoulder region at short exposures followed by an exponential decline during longer heating exposures. The Arrhenius curve showed a break at 42.3deg C and inactivation enthalpy was 1836 kJ/mol (438 kcal/mole) below the break point and 704 kJ/mole (168 kcal/mole) above the point. When bone marrow suspensions, obtained after either in vitro or in vivo irradiation, were heated in vitro at 42deg C for 60 min, supura-additive effect on cell survivals was observed by in vivo irradiation, but not observed by in vitro irradiation. Thermal enhancement ratio (TER), defined as D 0 of combined in vivo irradiation and in vitro heating divided by D 0 of the sole in vivo irradiation, was 1.12. In vivo heating following in vivo irradiation also showed supra-additive effect, giving TER of 1.66. These findings indicated that murine marrow CFU-GM is sensitive to hyperthermia and that thermal radiosensitization is never negligible when hyperthermia is employed with preceding X-irradiation. Thus, combined use of radiotherapy and hyperthermia may decrease bone marrow function. (N.K.)

  12. Manufacture of endothelial colony-forming progenitor cells from steady-state peripheral blood leukapheresis using pooled human platelet lysate.

    Science.gov (United States)

    Siegel, Georg; Fleck, Erika; Elser, Stefanie; Hermanutz-Klein, Ursula; Waidmann, Marc; Northoff, Hinnak; Seifried, Erhard; Schäfer, Richard

    2018-05-01

    Endothelial colony-forming progenitor cells (ECFCs) are promising candidates for cell therapies. However, ECFC translation to the clinic requires optimized isolation and manufacture technologies according to good manufacturing practice (GMP). ECFCs were manufactured from steady-state peripheral blood (PB) leukapheresis (11 donors), using GMP-compliant technologies including pooled human platelet (PLT) lysate, and compared to human umbilical cord endothelial cells, human aortic endothelial cells, and human cerebral microvascular endothelial cells. Specific variables assessed were growth kinetics, phenotype, trophic factors production, stimulation of tube formation, and Dil-AcLDL uptake. ECFCs could be isolated from PB leukapheresis units with mean processed volume of 5411 mL and mean white blood cell (WBC) concentration factor of 8.74. The mean frequency was 1.44 × 10 -8 ECFCs per WBC, corresponding to a mean of 177.8 ECFCs per apheresis unit. Expandable for up to 12 cumulative population doublings, calculated projection showed that approximately 730 × 10 3 ECFCs could be manufactured from 1 apheresis unit. ECFCs produced epidermal growth factor, hepatocyte growth factor, vascular endothelial growth factor (VEGF)-A, PLT-derived growth factor-B, interleukin-8, and monocyte chemoattractant protein-1, featured high potential for capillary-like tubes formation, and showed no telomerase activity. They were characterized by CD29, CD31, CD44, CD105, CD117, CD133, CD144, CD146, and VEGF-R2 expression, with the most common subpopulation CD34+CD117-CD133-. Compared to controls, ECFCs featured greater Dil-AcLDL uptake and higher expression of CD29, CD31, CD34, CD44, CD144, and VEGF-R2. Here we show that isolation of ECFCs with proangiogenic profile from steady-state PB leukapheresis is feasible, marking a first step toward ECFC product manufacture according to GMP. © 2018 AABB.

  13. The differentiated approach in forming swimming abilities and skills of students

    Directory of Open Access Journals (Sweden)

    Nikolskiy A.U.

    2010-09-01

    Full Text Available It is considered the directions of organization and methods of conducting of lessons with students. In experiment took part students of the 17-20 years old. The criteria of forming of typological educational groups are presented on the initial stage of teaching swimming of students. The degree of connection of the hereditarily conditioned swimming coordinating inclination is certain with the indexes of formed swimming abilities and skills of students. It is well-proven that a process of capture motive habits is under unreserved influence of conservative heredity of individual.

  14. Biofilm forming ability of bacteria isolated from necrotic roots canals of teeth

    Science.gov (United States)

    Alwan, Merriam Ghadhanfar; Usup, Gires; Heng, Lee Yook; Ahmad, Asmat

    2018-04-01

    The growth of microbes in biofilms are associated with repeated and chronic human infections and are extremely resistant to antimicrobial agents. The purpose of this study was to determine the diversity of bacteria from necrotic roots canals of teeth and to detect their biofilm formation ability. A total of 42 bacterial isolates were isolated and identified as belonging to 11 genera. These are Enterococcus sp. (21.4%) followed by Streptococcus sp. (16.8%), Bacillus sp. (11.9%), Peptostreptococcus sp. (9.5%), Staphylococcus sp. (9.5%), Bacteroides sp. (7.1%), Clostridium sp. (7.1%), Actinomyces sp. (7.1%), Fusobacterium sp. (4.76%), Provotella sp. (2.4%) and Chromobacterium sp. (2.4%). Three screening methods for biofilm forming ability were used. Congo Red Agar method (CRA), Tube method (TM) and Microtitre Plate (MTP). From the results, MTP method is a more reliable and quantitative method for the screening and detection of microorganism's ability to form biofilm. This method can be recommended and suggested as a general screening method for the detection of biofilm forming bacteria isolated from roots canals of teeth.

  15. Zr-Cu-Ni-Al bulk metallic glasses with superhigh glass-forming ability

    International Nuclear Information System (INIS)

    Sun, Y.J.; Qu, D.D.; Huang, Y.J.; Liss, K.-D.; Wei, X.S.; Xing, D.W.; Shen, J.

    2009-01-01

    Zr-Cu-Ni-Al quaternary amorphous alloy compositions with varying glass-forming ability are developed by an efficient method of proportional mixing of binary eutectics. The critical diameter of the glassy sample is improved from 6 mm for Zr 53 Cu 18.7 Ni 12 Al 16.3 to 14 mm for Zr 50.7 Cu 28 Ni 9 Al 12.3 by straightforwardly adjusting the eutectic unit's coefficients. The drastic improvement in GFA is attributed to balancing the chemical affinities of the Zr, Cu, Ni and Al components in the melt prior to solidification which makes the precipitation of competing crystalline phases more difficult. As the glass-forming ability increases, the concentration of Cu in the alloys exhibits a same trend. Based on synchrotron radiation high-energy X-ray diffraction analysis and Miracle's structural model, it is envisioned that the substitution of additional Cu atoms for Zr atoms in the investigated alloys stabilizes the efficient cluster packing structure of the amorphous alloys, leading to the pronounced increase in their glass-forming ability

  16. Effects of partitioned enthalpy of mixing on glass-forming ability

    Energy Technology Data Exchange (ETDEWEB)

    Song, Wen-Xiong; Zhao, Shi-Jin, E-mail: shijin.zhao@shu.edu.cn [Institute of Materials Science, Shanghai University, Shanghai 200072 (China)

    2015-04-14

    We explore the inherent reason at atomic level for the glass-forming ability of alloys by molecular simulation, in which the effect of partitioned enthalpy of mixing is studied. Based on Morse potential, we divide the enthalpy of mixing into three parts: the chemical part (Δ E{sub nn}), strain part (Δ E{sub strain}), and non-bond part (Δ E{sub nnn}). We find that a large negative Δ E{sub nn} value represents strong AB chemical bonding in AB alloy and is the driving force to form a local ordered structure, meanwhile the transformed local ordered structure needs to satisfy the condition (Δ E{sub nn}/2 + Δ E{sub strain}) < 0 to be stabilized. Understanding the chemical and strain parts of enthalpy of mixing is helpful to design a new metallic glass with a good glass forming ability. Moreover, two types of metallic glasses (i.e., “strain dominant” and “chemical dominant”) are classified according to the relative importance between chemical effect and strain effect, which enriches our knowledge of the forming mechanism of metallic glass. Finally, a soft sphere model is established, different from the common hard sphere model.

  17. Manipulation of the response of human endothelial colony-forming cells by focal adhesion assembly using gradient nanopattern plates.

    Science.gov (United States)

    Cui, Long-Hui; Joo, Hyung Joon; Kim, Dae Hwan; Seo, Ha-Rim; Kim, Jung Suk; Choi, Seung-Cheol; Huang, Li-Hua; Na, Ji Eun; Lim, I-Rang; Kim, Jong-Ho; Rhyu, Im Joo; Hong, Soon Jun; Lee, Kyu Back; Lim, Do-Sun

    2018-01-01

    Nanotopography plays a pivotal role in the regulation of cellular responses. Nonetheless, little is known about how the gradient size of nanostructural stimuli alters the responses of endothelial progenitor cells without chemical factors. Herein, the fabrication of gradient nanopattern plates intended to mimic microenvironment nanotopography is described. The gradient nanopattern plates consist of nanopillars of increasing diameter ranges [120-200 nm (GP 120/200), 200-280 nm (GP 200/280), and 280-360 nm (GP 280/360)] that were used to screen the responses of human endothelial colony-forming cells (hECFCs). Nanopillars with a smaller nanopillar diameter caused the cell area and perimeter of hECFCs to decrease and their filopodial outgrowth to increase. The structure of vinculin (a focal adhesion marker in hECFCs) was also modulated by nanostructural stimuli of the gradient nanopattern plates. Moreover, Rho-associated protein kinase (ROCK) gene expression was significantly higher in hECFCs cultured on GP 120/200 than in those on flat plates (no nanopillars), and ROCK suppression impaired the nanostructural-stimuli-induced vinculin assembly. These results suggest that the gradient nanopattern plates generate size-specific nanostructural stimuli suitable for manipulation of the response of hECFCs, in a process dependent on ROCK signaling. This is the first evidence of size-specific nanostructure-sensing behavior of hECFCs. Nano feature surfaces are of growing interest as materials for a controlled response of various cells. In this study, we successfully fabricated gradient nanopattern plates to manipulate the response of blood-derived hECFCs without any chemical stimulation. Interestingly, we find that the sensitive nanopillar size for manipulation of hECFCs is range between 120 nm and 200 nm, which decreased the area and increased the filopodial outgrowth of hECFCs. Furthermore, we only modulate the nanopillar size to increase ROCK expression can be an

  18. Effect of similar elements on improving glass-forming ability of La-Ce-based alloys

    International Nuclear Information System (INIS)

    Zhang Tao; Li Ran; Pang Shujie

    2009-01-01

    To date the effect of unlike component elements on glass-forming ability (GFA) of alloys have been studied extensively, and it is generally recognized that the main consisting elements of the alloys with high GFA usually have large difference in atomic size and atomic interaction (large negative heat of mixing) among them. In our recent work, a series of rare earth metal-based alloy compositions with superior GFA were found through the approach of coexistence of similar constituent elements. The quinary (La 0.5 Ce 0.5 ) 65 Al 10 (Co 0.6 Cu 0.4 ) 25 bulk metallic glass (BMG) in a rod form with a diameter up to 32 mm was synthesized by tilt-pour casting, for which the glass-forming ability is significantly higher than that for ternary Ln-Al-TM alloys (Ln = La or Ce; TM = Co or Cu) with critical diameters for glass-formation of several millimeters. We suggest that the strong frustration of crystallization by utilizing the coexistence of La-Ce and Co-Cu to complicate competing crystalline phases is helpful to construct BMG component with superior GFA. The results of our present work indicate that similar elements (elements with similar atomic size and chemical properties) have significant effect on GFA of alloys.

  19. Synthesis and devitrification of high glass-forming ability bulk metallic glasses.

    OpenAIRE

    Huang, Hong.

    2007-01-01

    In this thesis, literature on the production, microstructures and properties of bulk metallic glasses (BMG) has been reviewed with particular reference to glass forming ability (GFA) and alloys of the Fe-Zr-B and Zr-based BMG systems. The experimental procedures used in the research are presented and the results for the amorphous Fe80Zr12B8 ribbon and the Zr57Ti5Al10Cu20Ni8, Zr57Nb5Al10Cu20Ni8, Zr53Nb2Al8Cu30Ni7 BMGs are given and discussed. Wedge-shaped ingots of the Zr-based BMGs were produ...

  20. Discontinuities of Plastic Deformation in Metallic Glasses with Different Glass Forming Ability

    Science.gov (United States)

    Hurakova, Maria; Csach, Kornel; Miskuf, Jozef; Jurikova, Alena; Demcak, Stefan; Ocelik, Vaclav; Hosson, Jeff Th. M. De

    The metallic ribbons Fe40Ni40B20, Cu47Ti35Zr11Ni6Si1 and Zr65Cu17.5Ni10Al7.5 with different microhardness and glass forming ability were studied at different loading rates from 0.05 to 100 mN/s. We describe in details the differences in elemental discontinuities on the loading curves for the studied alloys. It was found that the discontinuities began at a certain local deformation independently on the macroscopic mechanical properties of a ribbon. More developed discontinuities at higher deformations are created for the materials with lower microhardness and so lower strength.

  1. The sea, the ship, the batle: survival of forms in 'Antologia da memória poética da Guerra Colonial'

    Directory of Open Access Journals (Sweden)

    Lisa Carvalho Vasconcellos

    2018-06-01

    Full Text Available The book Antologia da memória poética da guerra colonial was published in 2011 by Roberto Vecchi and Margarida Calafate Ribeiro. As a poetry anthology, its purpose was to collect and give meaning to the poetical ma­terial that was created and inspired by the wars that have taken place in 1962-74 between Portugal and it´s old colonies. Among the many themes and problems proposed by the poems compiled in the volume, the review and the reclaim of the ancient Portuguese literary tradition is the one that interest us. In Antologia da memória poética da guerra colonial, the old lite­rary forms – the Galician-Portuguese love lyric, the navigation chronicles, The Lusiads’, the historical figures and heroic myths – are revisited in a creative and imaginative way. Our hypothesis is that the presence of archaic and traditional elements in the Antologia indicates a form of survival (Na­chleben of past forms and tensions (cf. Aby Warburg, they are the traces of a literary tradition that renews itself from the same points (the sea, the conquer, the lost and the destruction.

  2. Devitrification behavior and glass-forming ability of Cu-Zr-Ag alloys

    International Nuclear Information System (INIS)

    Louzguine-Luzgin, Dmitri V.; Xie, Guoqiang; Zhang, Wei; Inoue, Akihisa

    2007-01-01

    This paper presents an influence of Ag addition on the glass-forming ability and devitrification behavior of Cu-Zr glassy alloys on heating. The crystallization kinetics and structure changes in Cu 45 Zr 45 Ag 10 and Cu 35 Zr 45 Ag 20 glassy alloys on heating were studied by X-ray diffraction, transmission electron microscopy, differential scanning and isothermal calorimetry methods. Based on the results obtained one can assume that the improvement of the glass-forming ability of the Cu-Zr alloys by the addition of Ag is connected with a particular crystallization mechanism and a higher reduced glass-transition temperature of the Cu 45 Zr 45 Ag 10 ternary alloy compared to the binary Cu 55 Zr 45 counterpart. As observed in the present work crystallization of the Cu-Zr-Ag alloys is found to cause embitterment of the samples and should be avoided as these alloys are considered to be used as structural materials. The Cu 35 Zr 45 Ag 20 alloy shows possible submicron-scale phase separation upon annealing

  3. Long-term musical training may improve different forms of visual attention ability.

    Science.gov (United States)

    Rodrigues, Ana Carolina; Loureiro, Maurício Alves; Caramelli, Paulo

    2013-08-01

    Many studies have suggested that structural and functional cerebral neuroplastic processes result from long-term musical training, which in turn may produce cognitive differences between musicians and non-musicians. We aimed to investigate whether intensive, long-term musical practice is associated with improvements in three different forms of visual attention ability: selective, divided and sustained attention. Musicians from symphony orchestras (n=38) and non-musicians (n=38), who were comparable in age, gender and education, were submitted to three neuropsychological tests, measuring reaction time and accuracy. Musicians showed better performance relative to non-musicians on four variables of the three visual attention tests, and such an advantage could not solely be explained by better sensorimotor integration. Moreover, in the group of musicians, significant correlations were observed between the age at the commencement of musical studies and reaction time in all visual attention tests. The results suggest that musicians present augmented ability in different forms of visual attention, thus illustrating the possible cognitive benefits of long-term musical training. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Accuracy of a selection criterion for glass forming ability in the Ni–Nb–Zr system

    International Nuclear Information System (INIS)

    Déo, L.P.; Oliveira, M.F. de

    2014-01-01

    Highlights: • We applied a selection in the Ni–Nb–Zr system to find alloys with high GFA. • We used the thermal parameter γ m to evaluate the GFA of alloys. • The correlation between the γ m parameter and R c in the studied system is poor. • The effect of oxygen impurity reduced dramatically the GFA of alloys. • Unknown intermetallic compounds reduced the accuracy of the criterion. - Abstract: Several theories have been developed and applied in metallic systems in order to find the best stoichiometries with high glass forming ability; however there is no universal theory to predict the glass forming ability in metallic systems. Recently a selection criterion was applied in the Zr–Ni–Cu system and it was found some correlation between experimental and theoretical data. This criterion correlates critical cooling rate for glass formation with topological instability of stable crystalline structures; average work function difference and average electron density difference among the constituent elements of the alloy. In the present work, this criterion was applied in the Ni–Nb–Zr system. It was investigated the influence of factors not considered in the calculation and on the accuracy of the criterion, such as unknown intermetallic compounds and oxygen contamination. Bulk amorphous specimens were produced by injection casting. The amorphous nature was analyzed by X-ray diffraction and differential scanning calorimetry; oxygen contamination was quantified by the inert gas fusion method

  5. Evaluation of the ability of Acinetobacter baumannii to form biofilms on six different biomedical relevant surfaces.

    Science.gov (United States)

    Greene, C; Wu, J; Rickard, A H; Xi, C

    2016-10-01

    The human opportunistic pathogen, Acinetobacter baumannii, has the propensity to form biofilms and frequently cause medical device-related infections in hospitals. However, the physio-chemical properties of medical surfaces, in addition to bacterial surface properties, will affect colonization and biofilm development. The objective of this study was to compare the ability of A. baumannii to form biofilms on six different materials common to the hospital environment: glass, porcelain, stainless steel, rubber, polycarbonate plastic and polypropylene plastic. Biofilms were developed on material coupons in a CDC biofilm reactor. Biofilms were visualized and quantified using fluorescent staining and imaged using confocal laser scanning microscopy (CLSM) and by direct viable cell counts. Image analysis of CLSM stacks indicated that the mean biomass values for biofilms grown on glass, rubber, porcelain, polypropylene, stainless steel and polycarbonate were 0·04, 0·26, 0·62, 1·00, 2·08 and 2·70 μm(3) /μm(2) respectively. Polycarbonate developed statistically more biofilm mass than glass, rubber, porcelain and polypropylene. Viable cell counts data were in agreement with the CLSM-derived data. In conclusion, polycarbonate was the most accommodating surface for A. baumannii ATCC 17978 to form biofilms while glass was least favourable. Alternatives to polycarbonate for use in medical and dental devices may need to be considered. In the hospital environment, Acinetobacter baumannii is one of the most persistent and difficult to control opportunistic pathogens. The persistence of A. baumannii is due, in part, to its ability to colonize surfaces and form biofilms. This study demonstrates that A. baumannii can form biofilms on a variety of different surfaces and develops substantial biofilms on polycarbonate - a thermoplastic material that is often used in the construction of medical devices. The findings highlight the need to further study the in

  6. Variation in the form of Pavlovian conditioned approach behavior among outbred male Sprague-Dawley rats from different vendors and colonies: sign-tracking vs. goal-tracking.

    Science.gov (United States)

    Fitzpatrick, Christopher J; Gopalakrishnan, Shyam; Cogan, Elizabeth S; Yager, Lindsay M; Meyer, Paul J; Lovic, Vedran; Saunders, Benjamin T; Parker, Clarissa C; Gonzales, Natalia M; Aryee, Emmanuel; Flagel, Shelly B; Palmer, Abraham A; Robinson, Terry E; Morrow, Jonathan D

    2013-01-01

    Even when trained under exactly the same conditions outbred male Sprague-Dawley (SD) rats vary in the form of the Pavlovian conditioned approach response (CR) they acquire. The form of the CR (i.e. sign-tracking vs. goal-tracking) predicts to what degree individuals attribute incentive salience to cues associated with food or drugs. However, we have noticed variation in the incidence of these two phenotypes in rats obtained from different vendors. In this study, we quantified sign- and goal-tracking behavior in a reasonably large sample of SD rats obtained from two vendors (Harlan or Charles River), as well as from individual colonies operated by both vendors. Our sample of rats acquired from Harlan had, on average, more sign-trackers than goal-trackers, and vice versa for our sample of rats acquired from Charles River. Furthermore, there were significant differences among colonies of the same vendor. Although it is impossible to rule out environmental variables, SD rats at different vendors and barriers may have reduced phenotypic heterogeneity as a result of genetic variables, such as random genetic drift or population bottlenecks. Consistent with this hypothesis, we identified marked population structure among colonies from Harlan. Therefore, despite sharing the same name, investigators should be aware that important genetic and phenotypic differences exist among SD rats from different vendors or even from different colonies of the same vendor. If used judiciously this can be an asset to experimental design, but it can also be a pitfall for those unaware of the issue.

  7. Variation in the form of Pavlovian conditioned approach behavior among outbred male Sprague-Dawley rats from different vendors and colonies: sign-tracking vs. goal-tracking.

    Directory of Open Access Journals (Sweden)

    Christopher J Fitzpatrick

    Full Text Available Even when trained under exactly the same conditions outbred male Sprague-Dawley (SD rats vary in the form of the Pavlovian conditioned approach response (CR they acquire. The form of the CR (i.e. sign-tracking vs. goal-tracking predicts to what degree individuals attribute incentive salience to cues associated with food or drugs. However, we have noticed variation in the incidence of these two phenotypes in rats obtained from different vendors. In this study, we quantified sign- and goal-tracking behavior in a reasonably large sample of SD rats obtained from two vendors (Harlan or Charles River, as well as from individual colonies operated by both vendors. Our sample of rats acquired from Harlan had, on average, more sign-trackers than goal-trackers, and vice versa for our sample of rats acquired from Charles River. Furthermore, there were significant differences among colonies of the same vendor. Although it is impossible to rule out environmental variables, SD rats at different vendors and barriers may have reduced phenotypic heterogeneity as a result of genetic variables, such as random genetic drift or population bottlenecks. Consistent with this hypothesis, we identified marked population structure among colonies from Harlan. Therefore, despite sharing the same name, investigators should be aware that important genetic and phenotypic differences exist among SD rats from different vendors or even from different colonies of the same vendor. If used judiciously this can be an asset to experimental design, but it can also be a pitfall for those unaware of the issue.

  8. The effect of assessment form to the ability of student to answer the problem correctly

    Directory of Open Access Journals (Sweden)

    Arifian Dimas

    2017-02-01

    Full Text Available Assessment is an important part of education. For educators, are collecting information about students learning and information about the learning process. For students, the assessment is the process of informing them about the progress of learning. Effective assessment process is responsive to the strengths, needs and clearly articulated student learning objectives. This research was aimed to know the effect of assessment form towards students ability in answering the problem correctly on kinematics and dynamics of motion. The method used in this research is descriptive qualitative. The data collecting method are assessment test and interview. Assessment test instrument are written test and animation form test. The question we use was taken "Force Concept Inventory" on kinematics and dynamics concepts. The sample are 36 student of 6th terms student of Physics Undergraduate Departement in Sebelas Maret University. The result shows that for kinematics concept, more students answer correctly for test presented in animation form but for dynamics concept conventional test is better.

  9. Glass forming ability and mechanical properties of Zr50Cu42Al8 bulk metallic glass

    International Nuclear Information System (INIS)

    Xia, L; Chan, K C; Wang, G; Liu, L

    2008-01-01

    In this work, we report that Zr 50 Cu 42 Al 8 bulk metallic glass (BMG) exhibits excellent glass forming ability and mechanical properties. Zr 50 Cu 42 Al 8 glassy rods with a diameter of 3 mm were prepared using conventional copper mould suction casting. The glassy rod exhibits a modulus of about 115 GPa and a fracture strength of about 2 GPa, and, as compared with other large-scale BMGs, it has excellent room-temperature plasticity of up to 20% under compression. The fracture mechanism of the rod was investigated by microstructural investigations, and it was found that the large plasticity of the as-cast rod is closely related to the in situ formation of nano-crystalline particles embedded in the amorphous matrix.

  10. Ductile Bulk Aluminum-Based Alloy with Good Glass-Forming Ability and High Strength

    International Nuclear Information System (INIS)

    Long-Chao, Zhuo; Shu-Jie, Pang; Hui, Wang; Tao, Zhang

    2009-01-01

    Based on a new approach for designing glassy alloy compositions, bulk Al-based alloys with good glass-forming ability (GFA) are synthesized. The cast Al 86 Si 0.5 Ni 4.06 Co 2.94 Y 6 Sc 0.5 rod with a diameter of 1 mm shows almost fully amorphous structure besides about 5% fcc-Al nucleated in the center of the rod. The bulk alloy with high Al concentration exhibits an ultrahigh yield strength of 1.18 GPa and maximum strength of 1.27 GPa as well as an obvious plastic strain of about 2.4% during compressive deformation. This light Al-based alloy with good GFA and mechanical properties is promising as a new high specific strength material with good deformability. (condensed matter: structure, mechanical and thermal properties)

  11. Fragility of superheated melts and glass-forming ability in Pr-based alloys

    International Nuclear Information System (INIS)

    Meng, Q.G.; Zhou, J.K.; Zheng, H.X.; Li, J.G.

    2006-01-01

    The kinetic viscosity (η) of superheated melts, thermal properties (T x , T m , T L ) and X-ray diffraction analysis on the Pr-based bulk metallic glasses (BMG) are reported and discussed. A new refined concept, the superheated fragility defined as M' = E S δ x /k B , has been developed based on common solidification theory and the Arrhenius equation. The interrelationship between this kind of fragility and the glass-forming ability (GFA) is elaborated on and evaluated in Pr-based BMG and Al-based amorphous ribbon alloys. Using viscosity data of superheated melts, it is shown, theoretically and experimentally, that the fragility parameter M' may be used as a GFA indicator for metallic alloys

  12. Durum Wheat (Triticum Durum Desf. Lines Show Different Abilities to Form Masked Mycotoxins under Greenhouse Conditions

    Directory of Open Access Journals (Sweden)

    Martina Cirlini

    2013-12-01

    Full Text Available Deoxynivalenol (DON is the most prevalent trichothecene in Europe and its occurrence is associated with infections of Fusarium graminearum and F. culmorum, causal agents of Fusarium head blight (FHB on wheat. Resistance to FHB is a complex character and high variability occurs in the relationship between DON content and FHB incidence. DON conjugation to glucose (DON-3-glucoside, D3G is the primary plant mechanism for resistance towards DON accumulation. Although this mechanism has been already described in bread wheat and barley, no data are reported so far about durum wheat, a key cereal in the pasta production chain. To address this issue, the ability of durum wheat to detoxify and convert deoxynivalenol into D3G was studied under greenhouse controlled conditions. Four durum wheat varieties (Svevo, Claudio, Kofa and Neodur were assessed for DON-D3G conversion; Sumai 3, a bread wheat variety carrying a major QTL for FHB resistance (QFhs.ndsu-3B, was used as a positive control. Data reported hereby clearly demonstrate the ability of durum wheat to convert deoxynivalenol into its conjugated form, D3G.

  13. Biofilm-Forming Abilities of Listeria monocytogenes Serotypes Isolated from Different Sources

    Science.gov (United States)

    Doijad, Swapnil P.; Barbuddhe, Sukhadeo B.; Garg, Sandeep; Poharkar, Krupali V.; Kalorey, Dewanand R.; Kurkure, Nitin V.; Rawool, Deepak B.; Chakraborty, Trinad

    2015-01-01

    A total of 98 previously characterized and serotyped L. monocytogenes strains, comprising 32 of 1/2a; 20 of 1/2b and 46 of 4b serotype, from clinical and food sources were studied for their capability to form a biofilm. The microtiter plate assay revealed 62 (63.26%) strains as weak, 27 (27.55%) strains as moderate, and 9 (9.18%) strains as strong biofilm formers. Among the strong biofilm formers, 6 strains were of serotype 1/2a and 3 strains were of serotype 1/2b. None of the strain from 4b serotype exhibited strong biofilm formation. No firm correlation (p = 0.015) was noticed between any serotype and respective biofilm formation ability. Electron microscopic studies showed that strong biofilm forming isolates could synthesize a biofilm within 24 h on surfaces important in food industries such as stainless steel, ceramic tiles, high-density polyethylene plastics, polyvinyl chloride pipes, and glass. Cell enumeration of strong, moderate, and weak biofilm was performed to determine if the number of cells correlated with the biofilm-forming capabilities of the isolates. Strong, moderate, and weak biofilm showed 570±127× 103 cells/cm2, 33±26× 103 cells/cm2, 5±3× 103 cells/cm2, respectively, indicating that the number of cells was directly proportional to the strength of the biofilm. The hydrophobicity index (HI) analysis revealed higher hydrophobicity with an increased biofilm formation. Fatty acid methyl esterase analysis revealed the amount of certain fatty acids such as iso-C15:0, anteiso-C15:0, and anteiso-C17:0 fatty acids correlated with the biofilm-forming capability of L. monocytogenes. This study showed that different strains of L. monocytogenes form biofilm of different intensities which did not completely correlate with their serotype; however, it correlated with the number of cells, hydrophobicity, and amount of certain fatty acids. PMID:26360831

  14. Biofilm-Forming Abilities of Listeria monocytogenes Serotypes Isolated from Different Sources.

    Directory of Open Access Journals (Sweden)

    Swapnil P Doijad

    Full Text Available A total of 98 previously characterized and serotyped L. monocytogenes strains, comprising 32 of 1/2a; 20 of 1/2b and 46 of 4b serotype, from clinical and food sources were studied for their capability to form a biofilm. The microtiter plate assay revealed 62 (63.26% strains as weak, 27 (27.55% strains as moderate, and 9 (9.18% strains as strong biofilm formers. Among the strong biofilm formers, 6 strains were of serotype 1/2a and 3 strains were of serotype 1/2b. None of the strain from 4b serotype exhibited strong biofilm formation. No firm correlation (p = 0.015 was noticed between any serotype and respective biofilm formation ability. Electron microscopic studies showed that strong biofilm forming isolates could synthesize a biofilm within 24 h on surfaces important in food industries such as stainless steel, ceramic tiles, high-density polyethylene plastics, polyvinyl chloride pipes, and glass. Cell enumeration of strong, moderate, and weak biofilm was performed to determine if the number of cells correlated with the biofilm-forming capabilities of the isolates. Strong, moderate, and weak biofilm showed 570±127× 103 cells/cm2, 33±26× 103 cells/cm2, 5±3× 103 cells/cm2, respectively, indicating that the number of cells was directly proportional to the strength of the biofilm. The hydrophobicity index (HI analysis revealed higher hydrophobicity with an increased biofilm formation. Fatty acid methyl esterase analysis revealed the amount of certain fatty acids such as iso-C15:0, anteiso-C15:0, and anteiso-C17:0 fatty acids correlated with the biofilm-forming capability of L. monocytogenes. This study showed that different strains of L. monocytogenes form biofilm of different intensities which did not completely correlate with their serotype; however, it correlated with the number of cells, hydrophobicity, and amount of certain fatty acids.

  15. Glass forming ability of Al–Ni–La alloys with Si addition

    Energy Technology Data Exchange (ETDEWEB)

    Yi, J.J.; Xiong, X.Z. [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Inoue, A. [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); WPI-Advanced Institute for Material Research, Tohoku University, Sendai 980-8577 (Japan); Kong, L.T. [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Li, J.F., E-mail: jfli@sjtu.edu.cn [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2015-11-25

    (Al{sub 85.5}Ni{sub 9.5}La{sub 5}){sub 100−x}Si{sub x}, (Al{sub 86}Ni{sub 9}La{sub 5}){sub 100−x}Si{sub x}, (Al{sub 86}Ni{sub 9.5}La{sub 4.5}){sub 100−x}Si{sub x}, (Al{sub 86}Ni{sub 10}La{sub 4}){sub 100−x}Si{sub x} and (Al{sub 86}Ni{sub 10.5}La{sub 3.5}){sub 100−x}Si{sub x} alloys, where x = 0.0, 0.2, 0.5, 1.0, 1.5 and 2.0, were cast under the same suction casting conditions into a wedge-shaped copper mold for investigating the effect of Si addition on the glass-forming ability (GFA). The GFA of the Al–Ni–La base alloys, except for the optimal glass former (Al{sub 85.5}Ni{sub 9.5}La{sub 5}), is enhanced when a proper content of Si is added. The largest content of Si up to which GFA can be enhanced changes in the following order of the base alloys: Al{sub 86}Ni{sub 9}La{sub 5}, Al{sub 86}Ni{sub 9.5}La{sub 4.5}, Al{sub 86}Ni{sub 10}La{sub 4} and Al{sub 86}Ni{sub 10.5}La{sub 3.5}. The enhancement of GFA due to Si addition becomes more significant as the La content decreases. This is presumably because more free Al atoms are present in the base alloy. - Highlights: • 0.2–2.0 at. % Si was added to each ternary base alloy. • Wedge-shaped samples were suction cast to obtain the glass-forming ability (GFA). • The GFA of the ternary non-optimal glass formers can be enhanced by Si addition. • The number of free-Al atoms dominates the best Si addition.

  16. Glass forming ability of Al–Ni–La alloys with Si addition

    International Nuclear Information System (INIS)

    Yi, J.J.; Xiong, X.Z.; Inoue, A.; Kong, L.T.; Li, J.F.

    2015-01-01

    (Al_8_5_._5Ni_9_._5La_5)_1_0_0_−_xSi_x, (Al_8_6Ni_9La_5)_1_0_0_−_xSi_x, (Al_8_6Ni_9_._5La_4_._5)_1_0_0_−_xSi_x, (Al_8_6Ni_1_0La_4)_1_0_0_−_xSi_x and (Al_8_6Ni_1_0_._5La_3_._5)_1_0_0_−_xSi_x alloys, where x = 0.0, 0.2, 0.5, 1.0, 1.5 and 2.0, were cast under the same suction casting conditions into a wedge-shaped copper mold for investigating the effect of Si addition on the glass-forming ability (GFA). The GFA of the Al–Ni–La base alloys, except for the optimal glass former (Al_8_5_._5Ni_9_._5La_5), is enhanced when a proper content of Si is added. The largest content of Si up to which GFA can be enhanced changes in the following order of the base alloys: Al_8_6Ni_9La_5, Al_8_6Ni_9_._5La_4_._5, Al_8_6Ni_1_0La_4 and Al_8_6Ni_1_0_._5La_3_._5. The enhancement of GFA due to Si addition becomes more significant as the La content decreases. This is presumably because more free Al atoms are present in the base alloy. - Highlights: • 0.2–2.0 at. % Si was added to each ternary base alloy. • Wedge-shaped samples were suction cast to obtain the glass-forming ability (GFA). • The GFA of the ternary non-optimal glass formers can be enhanced by Si addition. • The number of free-Al atoms dominates the best Si addition.

  17. Machine Learning Approach for Prediction and Understanding of Glass-Forming Ability.

    Science.gov (United States)

    Sun, Y T; Bai, H Y; Li, M Z; Wang, W H

    2017-07-20

    The prediction of the glass-forming ability (GFA) by varying the composition of alloys is a challenging problem in glass physics, as well as a problem for industry, with enormous financial ramifications. Although different empirical guides for the prediction of GFA were established over decades, a comprehensive model or approach that is able to deal with as many variables as possible simultaneously for efficiently predicting good glass formers is still highly desirable. Here, by applying the support vector classification method, we develop models for predicting the GFA of binary metallic alloys from random compositions. The effect of different input descriptors on GFA were evaluated, and the best prediction model was selected, which shows that the information related to liquidus temperatures plays a key role in the GFA of alloys. On the basis of this model, good glass formers can be predicted with high efficiency. The prediction efficiency can be further enhanced by improving larger database and refined input descriptor selection. Our findings suggest that machine learning is very powerful and efficient and has great potential for discovering new metallic glasses with good GFA.

  18. A simple criterion to predict the glass forming ability of metallic alloys

    International Nuclear Information System (INIS)

    Falcao de Oliveira, Marcelo

    2012-01-01

    A new and simple criterion with which to quantitatively predict the glass forming ability (GFA) of metallic alloys is proposed. It was found that the critical cooling rate for glass formation (R C ) correlates well with a proper combination of two factors, the minimum topological instability (λ min ) and the Δh parameter, which depends on the average work function difference (Δφ) and the average electron density difference (Δn ws 1/3 ) among the constituent elements of the alloy. A correlation coefficient (R 2 ) of 0.76 was found between R c and the new criterion for 68 alloys in 30 different metallic systems. The new criterion and the Uhlmann's approach were used to estimate the critical amorphous thickness (Z C ) of alloys in the Cu-Zr system. The new criterion underestimated R C in the Cu-Zr system, producing predicted Z C values larger than those observed experimentally. However, when considering a scale factor, a remarkable similarity was observed between the predicted and the experimental behavior of the GFA in the binary Cu-Zr. When using the same scale factor and performing the calculation for the ternary Zr-Cu-Al, good agreement was found between the predicted and the actual best GFA region, as well as between the expected and the observed critical amorphous thickness.

  19. A new parameter to evaluate the glass-forming ability of bulk metallic glasses

    International Nuclear Information System (INIS)

    Suo, Z.Y.; Qiu, K.Q.; Li, Q.F.; You, J.H.; Ren, Y.L.; Hu, Z.Q.

    2010-01-01

    Research highlights: → Develop a new criterion, i.e., Q=((T g +T x )/T l ).(ΔE/ΔH). → The reliability and benefits of the new criterion have been demonstrated in a wide range of BMG alloys. → It corresponds well with the critical diameter of BMGs investigated up to now. - Abstract: Based on the consideration of the liquid phase stability, the resistance to crystallization and the glass transition enthalpy, a new criterion Q, defined as ((T g + T x )/T l ).(ΔE/ΔH), where the T g , T x , T l , ΔE and ΔH are the glass transition temperature, the onset crystallization temperature, the liquidus temperature, the crystalline enthalpy and the fusion enthalpy, respectively, has been proposed for evaluating the glass-forming ability of bulk metallic glasses. The new criterion Q exhibits better correlation with the maximum cross section thickness (D m ) for glass formation compared with γ (=T x /(T l + T g )), T rg (=T g /T l ) and ΔT x (=T x - T g ) respectively. The available data from literatures and experiments have confirmed the effectiveness of the newly developed criterion.

  20. Investigation of biofilm forming ability in Staphylococci causing bovine mastitis using phenotypic and genotypic assays.

    Science.gov (United States)

    Darwish, Samah F; Asfour, Hanaa A E

    2013-01-01

    A total of 40 S. aureus and 68 coagulase negative Staphylococcus (CNS) isolates from bovine subclinical mastitis were investigated for their ability to form biofilm as one of the most important virulence factors.Using Congo Red Agar (CRA) method, 32.5%, 35%, and 32.5% of S. aureus strains were strong, intermediate, and negative biofilm producers, while in CNS the percentages were 29.5%, 42.6%, and 27.9%, respectively. By microtiter plate (MTP) method, 52.5%, 27.5%, and 20% of S. aureus isolates were strong, moderate, and weak biofilm producers, while in CNS the percentages were 44%, 30.9%, and 19.2%, respectively. Indian ink staining was used to detect the EPS layer of biofilm producers. All isolates were screened for presence of biofilm related genes, eno, icaA, icaD, and bap. In S. aureus isolates, the positive rates of eno, icaA, icaD, and bap genes were 75%, 15%, 62.5%, and 2.5% while in CNS were 92.6%, 5.9%, 47.1%, and 4.4%, respectively. The eno gene had the highest rate while the bap gene had the lowest rate. Presence of icaA and icaD genes was not always correlated with biofilm production. This study demonstrated high prevalence of Staphylococcus biofilm producers among bovine mastitis in Egypt. Therefore, attention must be paid toward implementation of new ways for effective treatment of such infections.

  1. The influence of interleukin-2, feeder cells, and timing of irradiation on the radiosensitivity of human T lymphocytes assessed by the colony-forming assay

    International Nuclear Information System (INIS)

    Gerber, M.; Guichard, M.; Pioch, Y.; Dubois, J.B.

    1989-01-01

    The radiosensitivity of human lymphocytes was investigated by the method of colony formation in the absence of interleukin-2 (IL2) and feeder cells, both of which enhance growth of T-cell colonies. The shape of the survival curve and the radiosensitivity was shown to depend upon the ability of lymphocytes to produce IL2: the survival curve for lymphocytes that were the most competent producers of IL2 is the closest to linearity; the lymphocytes that were poor producers show biphasic survival curves. The radiosensitivity of the lymphocytes from the first group is less than that of the latter, when the comparison is based on the first part of the biphasic survival curve. This is more easily seen when cultures are irradiated 24 h after stimulation by phytohemagglutinin (the time of the peak IL2 production) than when cultures are irradiated 2 h before stimulation. This study demonstrates that growth conditions influence the response of lymphocytes to irradiation and that optimal growth conditions result in a linear survival curve

  2. Engineering a pharmacologically superior form of granulocyte-colony-stimulating factor by fusion with gelatin-like-protein polymer.

    Science.gov (United States)

    Huang, Yan-Shan; Wen, Xiao-Fang; Wu, Yi-Liang; Wang, Ye-Fei; Fan, Min; Yang, Zhi-Yu; Liu, Wei; Zhou, Lin-Fu

    2010-03-01

    The plasma half-life of therapeutic proteins is a critical factor in many clinical applications. Therefore, new strategies to prolong plasma half-life of long-acting peptides and protein drugs are in high demand. Here, we designed an artificial gelatin-like protein (GLK) and fused this hydrophilic GLK polymer to granulocyte-colony-stimulating factor (G-CSF) to generate a chimeric GLK/G-CSF fusion protein. The genetically engineered recombinant GLK/G-CSF (rGLK/G-CSF) fusion protein was purified from Pichia pastoris. In vitro studies demonstrated that rGLK/G-CSF possessed an enlarged hydrodynamic radius, improved thermal stability and retained full bioactivity compared to unfused G-CSF. Following a single subcutaneous administration to rats, the rGLK/G-CSF fusion protein displayed a slower plasma clearance rate and stimulated greater and longer lasting increases in circulating white blood cells than G-CSF. Our findings indicate that fusion with this artificial, hydrophilic, GLK polymer provides many advantages in the construction of a potent hematopoietic factor with extended plasma half-life. This approach could be easily applied to other therapeutic proteins and have important clinical applications. (c) 2009 Elsevier B.V. All rights reserved.

  3. Culture on fibrin matrices maintains the colony-forming capacity and osteoblastic differentiation of mesenchymal stem cells

    International Nuclear Information System (INIS)

    Colley, Helen; McArthur, Sally L; Stolzing, Alexandra; Scutt, Andy

    2012-01-01

    Mesenchymal stem cells (MSC) are multipotent cells capable of differentiating into a number of mesenchymal tissues including bone, cartilage, and tendon. Low numbers in vivo means exponential growth is needed in culture to enable therapeutic applications. MSC can expand rapidly in culture but usually lose their extensive capacity for differentiation that makes them therapeutically attractive. To try and maintain their capacity for differentiation and expansion in vitro, we cultured MSC on fibrin gels of different concentrations to create more physiological growth conditions for the cells. The cells were then re-plated onto tissue culture plastic and analysed. The cells that had been pre-cultured for seven days on fibrin, proliferated and maintained their differential potential to the osteogenic lineage better than tissue culture plastic expanded MSC. A concentration relationship between colony number and fibrin concentration was seen with decreasing numbers as fibrin concentration increased. These data support the concept that substrate signals significantly influence MSC growth and differentiation and that growth on a fibrin matrix could be used to maintain a stem cell phenotype during MSC expansion. (paper)

  4. Dysregulation of endothelial colony-forming cell function by a negative feedback loop of circulating miR-146a and -146b in cardiovascular disease patients.

    Directory of Open Access Journals (Sweden)

    Ting-Yu Chang

    Full Text Available Functional impairment of endothelial colony-forming cells (ECFCs, a specific cell lineage of endothelial progenitor cells (EPCs is highly associated with the severity of coronary artery disease (CAD, the most common type of cardiovascular disease (CVD. Emerging evidence show that circulating microRNAs (miRNAs in CAD patients' body fluid hold a great potential as biomarkers. However, our knowledge of the role of circulating miRNA in regulating the function of ECFCs and the progression of CAD is still in its infancy. We showed that when ECFCs from healthy volunteers were incubated with conditioned medium or purified exosomes of cultured CAD ECFCs, the secretory factors from CAD ECFCs dysregulated migration and tube formation ability of healthy ECFCs. It is known that exosomes influence the physiology of recipient cells by introducing RNAs including miRNAs. By using small RNA sequencing (smRNA-seq, we deciphered the circulating miRNome in the plasma of healthy individual and CAD patients, and found that the plasma miRNA spectrum from CAD patients was significantly different from that of healthy control. Interestingly, smRNA-seq of both healthy and CAD ECFCs showed that twelve miRNAs that had a higher expression in the plasma of CAD patients also showed higher expression in CAD ECFCs when compared with healthy control. This result suggests that these miRNAs may be involved in the regulation of ECFC functions. For identification of potential mRNA targets of the differentially expressed miRNA in CAD patients, cDNA microarray analysis was performed to identify the angiogenesis-related genes that were down-regulated in CAD ECFCs and Pearson's correlation were used to identify miRNAs that were negatively correlated with the identified angiogenesis-related genes. RT-qPCR analysis of the five miRNAs that negatively correlated with the down-regulated angiogenesis-related genes in plasma and ECFC of CAD patients showed miR-146a-5p and miR-146b-5p up

  5. Improving the Ability of Mathematic Representation Capabilities and Students Skills in Importing Square Forms to Square Using Variation Solutions

    Science.gov (United States)

    Nirawati, R.

    2018-04-01

    This research was conducted to see whether the variation of the solution is acceptable and easy to understand by students with different level of ability so that it can be seen the difference of students ability in facilitating the quadratic form in the upper, middle and lower groups. This research used experimental method with factorial design. Based on the result of final test analysis, there were differences of students ability in upper group, medium group, and lower group in putting squared form based on the use certain variation of solution.

  6. Staphylococcus aureus Clinical Isolates: Antibiotic Susceptibility, Molecular Characteristics, and Ability to Form Biofilm

    Directory of Open Access Journals (Sweden)

    N. Indrawattana

    2013-01-01

    Full Text Available Periodic monitoring of Staphylococcus aureus characteristics in a locality is imperative as their drug-resistant variants cause treatment problem. In this study, antibiograms, prevalence of toxin genes (sea-see, seg-ser, seu, tsst-1, eta, etb, and etd, PFGE types, accessory gene regulator (agr groups, and ability to form biofilm of 92 S. aureus Thailand clinical isolates were investigated. They were classified into 10 drug groups: groups 1–7 (56 isolates were methicillin resistant (MRSA and 8–10 (36 isolates were methicillin sensitive (MSSA. One isolate did not have any toxin gene, 4 isolates carried one toxin gene (seq, and 87 isolates had two or more toxin genes. No isolate had see, etb, or tsst-1; six isolates had eta or etd. Combined seg-sei-sem-sen-seo of the highly prevalent egc locus was 26.1%. The seb, sec, sel, seu, and eta associated significantly with MSSA; sek was more in MRSA. The sek-seq association was 52.17% while combined sed-sej was not found. Twenty-three PFGE types were revealed, no association of toxin genes with PFGE types. All four agr groups were present; agr group 1 was predominant (58.70% but agr group 2 strains carried more toxin genes and were more frequent toxin producers. Biofilm formation was found in 72.83% of the isolates but there was no association with antibiograms. This study provides insight information on molecular and phenotypic markers of Thailand S. aureus clinical isolates which should be useful for future active surveillance that aimed to control a spread of existing antimicrobial resistant bacteria and early recognition of a newly emerged variant.

  7. Interspecific in vitro assay for the chimera-forming ability of human pluripotent stem cells.

    Science.gov (United States)

    Masaki, Hideki; Kato-Itoh, Megumi; Umino, Ayumi; Sato, Hideyuki; Hamanaka, Sanae; Kobayashi, Toshihiro; Yamaguchi, Tomoyuki; Nishimura, Ken; Ohtaka, Manami; Nakanishi, Mahito; Nakauchi, Hiromitsu

    2015-09-15

    Functional assay limitations are an emerging issue in characterizing human pluripotent stem cells (PSCs). With rodent PSCs, chimera formation using pre-implantation embryos is the gold-standard assay of pluripotency (competence of progeny to differentiate into all three germ layers). In human PSCs (hPSCs), however, this can only be monitored via teratoma formation or in vitro differentiation, as ethical concerns preclude generation of human-human or human-animal chimeras. To circumvent this issue, we developed a functional assay utilizing interspecific blastocyst injection and in vitro culture (interspecies in vitro chimera assay) that enables the development and observation of embryos up to headfold stage. The assay uses mouse pre-implantation embryos and rat, monkey and human PSCs to create interspecies chimeras cultured in vitro to the early egg-cylinder stage. Intra- and interspecific chimera assays with rodent PSC lines were performed to confirm the consistency of results in vitro and in vivo. The behavior of chimeras developed in vitro appeared to recapitulate that of chimeras developed in vivo; that is, PSC-derived cells survived and were integrated into the epiblast of egg-cylinder-stage embryos. This indicates that the interspecific in vitro chimera assay is useful in evaluating the chimera-forming ability of rodent PSCs. However, when human induced PSCs (both conventional and naïve-like types) were injected into mouse embryos and cultured, some human cells survived but were segregated; unlike epiblast-stage rodent PSCs, they never integrated into the epiblast of egg-cylinder-stage embryos. These data suggest that the mouse-human interspecies in vitro chimera assay does not accurately reflect the early developmental potential/process of hPSCs. The use of evolutionarily more closely related species as host embryos might be necessary to evaluate the developmental potency of hPSCs. © 2015. Published by The Company of Biologists Ltd.

  8. Investigation of Biofilm Forming Ability in Staphylococci Causing Bovine Mastitis Using Phenotypic and Genotypic Assays

    Directory of Open Access Journals (Sweden)

    Samah F. Darwish

    2013-01-01

    Full Text Available A total of 40 S. aureus and 68 coagulase negative Staphylococcus (CNS isolates from bovine subclinical mastitis were investigated for their ability to form biofilm as one of the most important virulence factors.Using Congo Red Agar (CRA method, 32.5%, 35%, and 32.5% of S. aureus strains were strong, intermediate, and negative biofilm producers, while in CNS the percentages were 29.5%, 42.6%, and 27.9%, respectively. By microtiter plate (MTP method, 52.5%, 27.5%, and 20% of S. aureus isolates were strong, moderate, and weak biofilm producers, while in CNS the percentages were 44%, 30.9%, and 19.2%, respectively. Indian ink staining was used to detect the EPS layer of biofilm producers. All isolates were screened for presence of biofilm related genes, eno, icaA, icaD, and bap. In S. aureus isolates, the positive rates of eno, icaA, icaD, and bap genes were 75%, 15%, 62.5%, and 2.5% while in CNS were 92.6%, 5.9%, 47.1%, and 4.4%, respectively. The eno gene had the highest rate while the bap gene had the lowest rate. Presence of icaA and icaD genes was not always correlated with biofilm production. This study demonstrated high prevalence of Staphylococcus biofilm producers among bovine mastitis in Egypt. Therefore, attention must be paid toward implementation of new ways for effective treatment of such infections.

  9. Validation of an Adapted French Form of the Career Adapt-Abilities Scale in Four Francophone Countries

    Science.gov (United States)

    Johnston, Claire S.; Broonen, Jean-Paul; Stauffer, Sarah D.; Hamtiaux, Armanda; Pouyaud, Jacques; Zecca, Gregory; Houssemand, Claude; Rossier, Jerome

    2013-01-01

    This study presents the validation of a French version of the Career Adapt-Abilities Scale in four Francophone countries. The aim was to re-analyze the item selection and then compare this newly developed French-language form with the international form 2.0. Exploratory factor analysis was used as a tool for item selection, and confirmatory factor…

  10. Insight on the glass-forming ability of Al–Y–Ni–Ce bulk metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shih-Fan, E-mail: sfchen@ntut.edu.tw [Institute of Materials Science and Engineering, National Taipei University of Technology, Taipei 106, Taiwan (China); Chen, Chih-Yuan, E-mail: chen6563@gmail.com [Department of Energy Engineering, National United University, Miaoli 36003, Taiwan (China); Lin, Chia-Hung [Institute of Materials Science and Engineering, National Taipei University of Technology, Taipei 106, Taiwan (China)

    2015-07-15

    Highlights: • Adding 1 at.% cerium to Al{sub 87}Y{sub 8}Ni{sub 5} alloy causes glass transition. • A large ΔT{sub x} indicates that (Al{sub 87}Y{sub 8}Ni{sub 5}){sub 99}Ce{sub 1} is possibly a ductile amorphous alloy. • Ce is effective in improving the thermal stability of the Al–Y–Ni amorphous alloy. • The hardness of the crystallized cerium-bearing alloy was as high as 593 Hv. - Abstract: In the present study, the role of Ce in the thermal stability and glass forming ability (GFA) of (Al{sub 87}Y{sub 8}Ni{sub 5}){sub 99}Ce{sub 1} alloy ribbons produced by a single roller melt-spinning process has been investigated in an attempt to understand the influences of multiple RE elements in an Al–TM–RE (TM: transition metal, RE: rear earth metal) alloy system. Only the (Al{sub 87}Y{sub 8}Ni{sub 5}){sub 99}Ce{sub 1} alloy ribbon showed a glass transition temperature (T{sub g}) at 483.2 K, and its ΔT{sub x} value was 41.3 K. Crystallization occurred in the temperature range of 500–750 K in three exothermic reaction stages. The peak temperature for these reactions shifted toward higher temperatures at higher heating rates. XRD and SEM analysis of annealed samples revealed that nano-sized Al particles precipitated within the amorphous matrix during the first exothermic reaction. The maximum hardness was obtained for both non-cerium and cerium addition alloys after crystallization in the 550–660 K region due to numerous nano-sized precipitates randomly and homogeneously distributed in the amorphous matrix. Moreover, from observation of the fracture surface, it is found that the fracture mode transforms from ductile to brittle when the sample is annealed at a higher crystallization temperature, at which brittle intermetallic compounds appear.

  11. Y and Er minor addition effect on glass forming ability of a Ni–Nb–Zr alloy

    International Nuclear Information System (INIS)

    Deo, L.P.; Oliveira, M.F. de

    2015-01-01

    Highlights: • A theoretical selection criterion to predict the GFA was used for Ni–Nb–Zr–RE alloys. • The prediction agrees very well with thermal parameter gm used to evaluate experimentally the GFA. • RE doped alloys showed higher GFA than the base alloy. • Y and Er elements showed similar effects to improve the GFA of the base alloy. - Abstract: Since the discovering of amorphous alloys in 1960, the actual causes of why some alloys can be easily formed into glasses while others cannot, are not clearly known, thus there is no universal theory to predict the glass forming ability in metallic systems. It is well known that the minor amount addition of proper rare-earth elements can greatly enhance the glass forming ability of some glass-forming alloys. In the present study, a selection criterion was successfully used to predict the glass forming ability improvement of Ni 67.3 Nb 28.4 Zr 4.3 alloy with minor additions of Y or Er. The actual glass forming ability of the base alloy and rare-earth doped alloys were evaluated by the thermal parameter γ m and the results agree very well with the tendency predicted by the calculation. The amorphous nature of alloys was mainly analyzed by X-ray diffraction and differential scanning calorimetry. This work also presents a brief and complementary consideration about oxygen contamination quantified by the inert gas fusion method

  12. Long-Term Expansion in Platelet Lysate Increases Growth of Peripheral Blood-Derived Endothelial-Colony Forming Cells and Their Growth Factor-Induced Sprouting Capacity.

    Science.gov (United States)

    Tasev, Dimitar; van Wijhe, Michiel H; Weijers, Ester M; van Hinsbergh, Victor W M; Koolwijk, Pieter

    2015-01-01

    Efficient implementation of peripheral blood-derived endothelial-colony cells (PB-ECFCs) as a therapeutical tool requires isolation and generation of a sufficient number of cells in ex vivo conditions devoid of animal-derived products. At present, little is known how the isolation and expansion procedure in xenogeneic-free conditions affects the therapeutical capacity of PB-ECFCs. The findings presented in this study indicate that human platelet lysate (PL) as a serum substitute yields twice more colonies per mL blood compared to the conventional isolation with fetal bovine serum (FBS). Isolated ECFCs displayed a higher proliferative ability in PL supplemented medium than cells in FBS medium during 30 days expansion. The cells at 18 cumulative population doubling levels (CPDL) retained their proliferative capacity, showed higher sprouting ability in fibrin matrices upon stimulation with FGF-2 and VEGF-A than the cells at 6 CPDL, and displayed low β-galactosidase activity. The increased sprouting of PB-ECFCs at 18 CPDL was accompanied by an intrinsic activation of the uPA/uPAR fibrinolytic system. Induced deficiency of uPA (urokinase-type plasminogen activator) or uPAR (uPA receptor) by siRNA technology completely abolished the angiogenic ability of PB-ECFCs in fibrin matrices. During the serial expansion, the gene induction of the markers associated with inflammatory activation such as VCAM-1 and ICAM-1 did not occur or only to limited extent. While further propagation up to 31 CPDL proceeded at a comparable rate, a marked upregulation of inflammatory markers occurred in all donors accompanied by a further increase of uPA/uPAR gene induction. The observed induction of inflammatory genes at later stages of long-term propagation of PB-ECFCs underpins the necessity to determine the right time-point for harvesting of sufficient number of cells with preserved therapeutical potential. The presented isolation method and subsequent cell expansion in platelet lysate

  13. Long-Term Expansion in Platelet Lysate Increases Growth of Peripheral Blood-Derived Endothelial-Colony Forming Cells and Their Growth Factor-Induced Sprouting Capacity.

    Directory of Open Access Journals (Sweden)

    Dimitar Tasev

    Full Text Available Efficient implementation of peripheral blood-derived endothelial-colony cells (PB-ECFCs as a therapeutical tool requires isolation and generation of a sufficient number of cells in ex vivo conditions devoid of animal-derived products. At present, little is known how the isolation and expansion procedure in xenogeneic-free conditions affects the therapeutical capacity of PB-ECFCs.The findings presented in this study indicate that human platelet lysate (PL as a serum substitute yields twice more colonies per mL blood compared to the conventional isolation with fetal bovine serum (FBS. Isolated ECFCs displayed a higher proliferative ability in PL supplemented medium than cells in FBS medium during 30 days expansion. The cells at 18 cumulative population doubling levels (CPDL retained their proliferative capacity, showed higher sprouting ability in fibrin matrices upon stimulation with FGF-2 and VEGF-A than the cells at 6 CPDL, and displayed low β-galactosidase activity. The increased sprouting of PB-ECFCs at 18 CPDL was accompanied by an intrinsic activation of the uPA/uPAR fibrinolytic system. Induced deficiency of uPA (urokinase-type plasminogen activator or uPAR (uPA receptor by siRNA technology completely abolished the angiogenic ability of PB-ECFCs in fibrin matrices. During the serial expansion, the gene induction of the markers associated with inflammatory activation such as VCAM-1 and ICAM-1 did not occur or only to limited extent. While further propagation up to 31 CPDL proceeded at a comparable rate, a marked upregulation of inflammatory markers occurred in all donors accompanied by a further increase of uPA/uPAR gene induction. The observed induction of inflammatory genes at later stages of long-term propagation of PB-ECFCs underpins the necessity to determine the right time-point for harvesting of sufficient number of cells with preserved therapeutical potential.The presented isolation method and subsequent cell expansion in platelet

  14. Characteristics of cells producing stimulator for the proliferation of colony forming unit-spleen (CFU-S)

    International Nuclear Information System (INIS)

    Abdul Manaf Ali; Wright, E.G.; Riches, A.C.

    1994-01-01

    The presence of stimulator for haemopoietic stem cell (CFU-S) proliferation in regenerating bone marrow was assayed by incubating the conditioned medium (CM) prepared from bone marrow with quiescent CFU-S from normal bone marrow. The percentage of CFU-S normal bone marrow in DNA synthesis increased more than 30 percent after incubating with CM of 4.5 Gy regenerating bone marrow. Stimulator was also present in bone marrow of mice at 9.0 Gy whole body X-irradiation. However the conditioned medium prepared from regenerating bone marrow without Fc and Ia-2k cells failed to increase the percentage of CFU-S in DNA synthesis. On the other hand, elimination of Thy 1.2 positive cells with complement cytolysis did not affect the ability of regenerating bone marrow to produce stimulator. These observations suggest that the stimulator producing cells are radio-resistant, Thy 1.2 negative, Fc and Ia-2k positive

  15. Physiological integration affects growth form and competitive ability in clonal plants

    Czech Academy of Sciences Publication Activity Database

    Herben, Tomáš

    2004-01-01

    Roč. 18, - (2004), s. 493-520 ISSN 0269-7653 R&D Projects: GA ČR(CZ) GA206/02/0953 Institutional research plan: CEZ:AV0Z6005908 Keywords : competitive ability * Physiological integration * clonal plants Subject RIV: EF - Botanics Impact factor: 3.215, year: 2004

  16. Developmental Abilities to Form Chunks in Immediate Memory and its Non-Relationship to Span Development

    Directory of Open Access Journals (Sweden)

    Fabien eMathy

    2016-02-01

    Full Text Available Both adults and children --by the time they are two to three years old-- have a general ability to recode information to increase memory efficiency. This paper aims to evaluate the ability of untrained children aged six to ten years old to deploy such a recoding process in immediate memory. A large sample of 374 children were given a task of immediate serial report based on SIMON, a classic memory game made of four colored buttons (red, green, yellow, blue requiring players to reproduce a sequence of colors within which repetitions eventually occur. It was hypothesized that a primitive ability across all ages (since theoretically already available in toddlers to detect redundancies allows the span to increase whenever information can be recoded on the fly. The chunkable condition prompted the formation of chunks based on the perceived structure of color repetition within to-be-recalled sequences of colors. Our result shows a similar linear improvement of memory span with age for both chunkable and non-chunkable conditions. The amount of information retained in immediate memory systematically increased for the groupable sequences across all age groups, independently of the average age-group span that was measured on sequences that contained fewer repetitions. This result shows that chunking gives young children an equal benefit as older children. We discuss the role of recoding in the expansion of capacity in immediate memory and the potential role of data compression in the formation of chunks in long-term memory.

  17. Developmental Abilities to Form Chunks in Immediate Memory and Its Non-Relationship to Span Development.

    Science.gov (United States)

    Mathy, Fabien; Fartoukh, Michael; Gauvrit, Nicolas; Guida, Alessandro

    2016-01-01

    Both adults and children -by the time they are 2-3 years old- have a general ability to recode information to increase memory efficiency. This paper aims to evaluate the ability of untrained children aged 6-10 years old to deploy such a recoding process in immediate memory. A large sample of 374 children were given a task of immediate serial report based on SIMON®, a classic memory game made of four colored buttons (red, green, yellow, blue) requiring players to reproduce a sequence of colors within which repetitions eventually occur. It was hypothesized that a primitive ability across all ages (since theoretically already available in toddlers) to detect redundancies allows the span to increase whenever information can be recoded on the fly. The chunkable condition prompted the formation of chunks based on the perceived structure of color repetition within to-be-recalled sequences of colors. Our result shows a similar linear improvement of memory span with age for both chunkable and non-chunkable conditions. The amount of information retained in immediate memory systematically increased for the groupable sequences across all age groups, independently of the average age-group span that was measured on sequences that contained fewer repetitions. This result shows that chunking gives young children an equal benefit as older children. We discuss the role of recoding in the expansion of capacity in immediate memory and the potential role of data compression in the formation of chunks in long-term memory.

  18. Ability of nitrones of various structures to control the radical polymerization of styrene mediated by in situ formed nitroxides.

    NARCIS (Netherlands)

    Sciannamea, V.; Guerrero-Sanchez, C.A.; Schubert, U.S.; Catala, J.-M.; Jerome, R.; Detrembleur, C.

    2005-01-01

    The ability of several nitrones to control the radical polymerization of styrene at 110 °C has been investigated by high-throughput experimentation. The nitrone/free radical initiator pair dictates the structure of the nitroxide and the alkoxyamine formed in situ, which determines the position of

  19. Plasticity of Ability to Form Cross-Modal Representations in Infant Japanese Macaques

    Science.gov (United States)

    Adachi, Ikuma; Kuwahata, Hiroko; Fujita, Kazuo; Tomonaga, Masaki; Matsuzawa, Tetsuro

    2009-01-01

    In a previous study, Adachi, Kuwahata, Fujita, Tomonaga & Matsuzawa demonstrated that infant Japanese macaques (Macaca fuscata) form cross-modal representations of conspecifics but not of humans. However, because the subjects in the experiment were raised in a large social group and had considerably less exposure to humans than to…

  20. Method of monolayer cultures of the guinea pig spleen used to evaluate the radioprotective action of mexamine on the survival of colony-forming cells. [Method of monolayer cultures, quantitative estimation of radioprotective action of drugs

    Energy Technology Data Exchange (ETDEWEB)

    Baisogolov, G D; Rudakova, S F; Rudakov, I A; Konoplyannikov, A G [Akademiya Meditsinskikh Nauk SSSR, Obninsk. Nauchno-Issledovatel' skij Inst. Meditsinskoj Radiologii

    1976-01-01

    Dose dependent survival of colony-forming splenic cells of guinea pigs has been studied after ..gamma..-irradiation in vitro. The average lethal dose (D/sub 0/) for colony-forming cells is 245 rads, the extrapolation number - 1.5. Radiosensitivity of the splenic cells is markedly lower than that of the bone marrow cells (128 rads). After intraperitoneal administration of mexamine (150 mg/kg) to guinea pigs 10-15 min before irradiation, D/sub 0/ increases up to 319 rads, extrapolation number is 1.4, and DRF is 1.3.

  1. Dynamic stabilities of icosahedral-like clusters and their ability to form quasicrystals

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Xiaogang; Hamid, Ilyar; Duan, Haiming, E-mail: dhm@xju.edu.cn [College of Physics Science and Technology. Xinjiang University, Urumqi 830046 (China)

    2016-06-15

    The dynamic stabilities of the icosahedral-like clusters containing up to 2200 atoms are investigated for 15 metal elements. The clusters originate from five different initial structures (icosahedron, truncated decahedron, octahedron, closed-shell fragment of an HCP structure, and non-closed-shell fragment of an HCP structure). The obtained order of the dynamic stabilities of the icosahedral-like clusters can be assigned to three groups, from stronger to weaker, according to the size ranges involved: (Zr, Al, Ti) > (Cu, Fe, Co, Ni, Mg, Ag) > (Pb, Au, Pd, Pt, Rh, Ir), which correspond to the predicted formation ability of the quasicrystals. The differences of the sequences can be explained by analyzing the parameters of the Gupta-type many-body inter-atomic potentials.

  2. Unusual glass-forming ability induced by changes in the local atomic structure in Ti-based bulk metallic glass

    International Nuclear Information System (INIS)

    Kim, Y C; Chang, H J; Kim, D H; Kim, W T; Cha, P R

    2007-01-01

    The effect of partial replacement of Cu by Be in Ti 50 Cu 32 Ni 15 Sn 3 alloy on the thermal properties, structure, and forming ability of an amorphous phase were investigated by differential scanning calorimetry (DSC), x-ray diffraction (XRD), extended x-ray absorption fine structure (EXAFS), and high-resolution transmission electron microscopy (HRTEM). Ti 50 Cu 25 Ni 15 Sn 3 Be 7 alloy shows enhanced glass-forming ability, enabling one to fabricate a fully amorphous bulk metallic glass sample 2 mm in diameter by injection casting. With the replacement, the supercooled liquid region ΔT x (= T x -T g , where T x is the crystallization temperature and T g is the glass transition temperature) decreased from 73 to 45 K and the reduced glass transition temperature T rg (= T g /T 1 , where T 1 is the liquidus temperature) increased from 0.53 to 0.57. The amorphous Ti 50 Cu 25 Ni 15 Sn 3 Be 7 phase showed a formation of short-range-ordered clusters 1-2 nm in size, which is attributed to the strong interaction between Ti and Be. The results show that ΔT x can be used as a thermal parameter reflecting the glass-forming ability of the alloy only when the phase formed during crystallization is the same as the phase competing with the glass transition during solidification

  3. Clinical isolates of Acinetobacter baumannii from a Portuguese hospital: PFGE characterization, antibiotic susceptibility and biofilm-forming ability.

    Science.gov (United States)

    Duarte, Andreia; Ferreira, Susana; Almeida, Sofia; Domingues, Fernanda C

    2016-04-01

    Acinetobacter baumannii is an emerging pathogen associated with nosocomial infections that in addition has shown an increasing resistance to antibiotics. In this work the genetic diversity of A. baumannii isolates from a Portuguese hospital, their antibiotic resistance profiles and ability to form biofilms was studied. Seventy-nine clinical A. baumannii isolates were characterized by pulsed-field gel electrophoresis (PFGE) with 9 different PFGE profiles being obtained. Concerning the antimicrobial susceptibility, all A. baumannii isolates were resistant to 12 of the 17 tested antibiotics and classified as multidrug-resistant (MDR). In addition, 74.7% of the isolates showed biofilm formation ability, however no statistical significance with antibiotic resistance was observed. In contrast, urine samples isolates were more likely to form biofilms than strains isolated from other sources. Our findings highlight the high number of MDR A. baumannii isolates and the importance of the formation of biofilms as a potential virulence factor. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Structural Origin of the Enhanced Glass-Forming Ability Induced by Microalloying Y in the ZrCuAl Alloy

    Directory of Open Access Journals (Sweden)

    Gu-Qing Guo

    2016-03-01

    Full Text Available In this work, the structural origin of the enhanced glass-forming ability induced by microalloying Y in a ZrCuAl multicomponent system is studied by performing synchrotron radiation experiments combined with simulations. It is revealed that the addition of Y leads to the optimization of local structures, including: (1 more Zr-centered and Y-centered icosahedral-like clusters occur in the microstructure; (2 the atomic packing efficiency inside clusters and the regularity of clusters are both enhanced. These structural optimizations help to stabilize the amorphous structure in the ZrCuAlY system, and lead to a high glass-forming ability (GFA. The present work provides an understanding of GFAs in multicomponent alloys and will shed light on the development of more metallic glasses with high GFAs.

  5. Biological Behavior of Osteoblast Cell and Apatite Forming Ability of the Surface Modified Ti Alloys.

    Science.gov (United States)

    Zhao, Jingming; Hwang, K H; Choi, W S; Shin, S J; Lee, J K

    2016-02-01

    Titanium as one kind of biomaterials comes in direct contact with the body, making evaluation of biocompatibility an important aspect to biomaterials development. Surface chemistry of titanium plays an important role in osseointegration. Different surface modification alters the surface chemistry and result in different biological response. In this study, three kinds of mixed acid solutions were used to treat Ti specimens to induce Ca-P formation. Following a strong mixed acid activation process, Ca-P coating successfully formed on the Ti surfaces in simulated body fluid. Strong mixed acid increased the roughness of the metal surface, because the porous and rough surface allows better adhesion between Ca-P coatings and substrates. After modification of titanium surface by mixed acidic solution and subsequently H2O2/HCL treatment evaluation of biocompatibility was conducted from hydroxyapatite formation by biomimetic process and cell viability on modified titanium surface. Nano-scale modification of titanium surfaces can alter cellular and tissue responses, which may benefit osseointegration and dental implant therapy. Results from this study indicated that surface treatment methods affect the surface morphology, type of TiO2 layer formed and subsequent apatite deposition and biological responses. The thermo scientific alamarblue cell viability assay reagent is used to quantitatively measure the viability of mammalian cell lines, bacteria and fungi by incorporating a rapid, sensitive and reliable fluorometric/colorimetric growth indicator, without any toxic and side effect to cell line. In addition, mixed acid treatment uses a lower temperature and shorter time period than widely used alkali treatment.

  6. Investigation of the antibiotic resistance and biofilm-forming ability of Staphylococcus aureus from subclinical bovine mastitis cases.

    Science.gov (United States)

    Aslantaş, Özkan; Demir, Cemil

    2016-11-01

    A total of 112 Staphylococcus aureus isolates obtained from subclinical bovine mastitis cases were examined for antibiotic susceptibility and biofilm-forming ability as well as genes responsible for antibiotic resistance, biofilm-forming ability, and adhesin. Antimicrobial susceptibility of the isolates were determined by disk diffusion method. Biofilm forming ability of the isolates were investigated by Congo red agar method, standard tube method, and microplate method. The genes responsible for antibiotic resistance, biofilm-forming ability, and adhesion were examined by PCR. Five isolates (4.5%) were identified as methicillin-resistant Staph. aureus by antibiotic susceptibility testing and confirmed by mecA detection. The resistance rates to penicillin, ampicillin, tetracycline, erythromycin, trimethoprim-sulfamethoxazole, enrofloxacin, and amoxicillin-clavulanic acid were 45.5, 39.3, 33, 26.8, 5.4, 0.9, and 0.9%, respectively. All isolates were susceptible against vancomycin and gentamicin. The blaZ (100%), tetK (67.6%), and ermA (70%) genes were the most common antibiotic-resistance genes. Using Congo red agar, microplate, and standard tube methods, 70.5, 67, and 62.5% of the isolates were found to be biofilm producers, respectively. The percentage rate of icaA, icaD, and bap genes in Staph. aureus isolates were 86.6, 86.6, and 13.4%, respectively. The adhesion molecules fnbA, can, and clfA were detected in 87 (77.7%), 98 (87.5%), and 75 (70%) isolates, respectively. The results indicated that Staph. aureus from sublinical bovine mastitis cases were mainly resistant to β-lactams and, to a lesser extent, to tetracycline and erythromycin. Also, biofilm- and adhesion-related genes, which are increasingly accepted as an important virulence factor in the pathogenesis of Staph. aureus infections, were detected at a high rate. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  7. Glass-forming ability and crystallization behavior of some binary and ternary Ni-based glassy alloys

    International Nuclear Information System (INIS)

    Louzguine-Luzgin, Dmitri V.; Louzguina-Luzgina, Larissa V.; Xie Guoqiang; Li Song; Zhang Wei; Inoue, Akihisa

    2008-01-01

    The purpose of the current paper is to study the influence of Ti, V, Nb, Al, Sn and Pd additions on the glass-forming ability, formation of a supercooled liquid region and a devitrification process of some Ni-Zr glassy alloys as well as to compare the results with those obtained for similar Cu-based alloys studied earlier. The Ni-based glassy alloys were investigated by using X-ray diffraction, differential scanning and isothermal calorimetries. Although the studied Ni-based alloys showed high values of the reduced glass-transition temperature of about 0.6, their glass-forming ability is quite low. This fact may be explained by low stability of the supercooled liquid against crystallization and formation of the equilibrium intermetallic compounds with a high growth rate compared to those observed in similar Cu-based alloys studied earlier. Relatively low thermal conductivity of Ni-based alloys is also found to be another factor limiting their glass-forming ability

  8. About forming of personality physical culture of students in the process of physical education (in aspect of presence of abilities

    Directory of Open Access Journals (Sweden)

    S.I. Belykh

    2013-01-01

    Full Text Available It is shown that practice of teaching of discipline «Physical education» does not provide forming of volume of abilities, sufficient for the origin of athletic activity. Prevail ability to pick up a place, sporting form, inventory depending on the type of physical exercises and ability on the observance of rules of the personal hygiene. In the questionnaire questioning 650 students (324 youths and 326 girls of the first and fourth courses took part. All of students visited employments on physical education at school and institute of higher. It is marked that the important task of amateurish athletic education is forming for the students of the personal experience of independent athletic, health and рекреационных employments. It is underlined that sense of amateurish athletic education of students consists in achievement by a man unity of mental and activity processes. Such processes are needed for an estimation and understanding of the state of the health, programming and residence of healthy way of life.

  9. New insight on glass-forming ability and designing Cu-based bulk metallic glasses: The solidification range perspective

    International Nuclear Information System (INIS)

    Wu, Jili; Pan, Ye; Li, Xingzhou; Wang, Xianfei

    2014-01-01

    Highlights: • The equation, T rg = T g /T l , was rotationally modified to T rg = κ(T m /T l ) + C/T l . • The newly generalized equation suggests a way for describing glass-forming ability. • Several new Cu-based bulk metallic glasses were discovered by solidification range. - Abstract: In this paper, a new equation was rationally generalized from the reduced glass transition temperature. This equation indicates that solidification range can be used for describing glass-forming ability, which can be calculated with the aid of computational thermodynamic approach. Based on this scenario, several new Cu-based bulk metallic glasses in the ternary Cu–Zr–Ti alloy system were discovered. The as-cast samples were characterized by X-ray diffraction and transmission electronic microscopy. The results indicate that as-cast samples have monolithic amorphous nature. Thermal analysis validates that the smaller solidification range is closely related to the higher glass-forming ability, which is contributed to the effect of solidification time on the formation of bulk metallic glasses. This work also suggests that solidus can influence glass formation

  10. Effect of Nb on glass forming ability and plasticity of (Ti-Cu)-based bulk metallic glasses

    International Nuclear Information System (INIS)

    Suo, Z.Y.; Qiu, K.Q.; Li, Q.F.; Ren, Y.L.; Hu, Z.Q.

    2010-01-01

    A Ti 33 Cu 47 Zr 9 Ni 6 Sn 2 Si 1 Nb 2 bulk metallic glass has been developed by Nb partial substitution for Zr in Ti 33 Cu 47 Zr 11 Ni 6 Sn 2 Si 1 alloy. The glass forming ability Ti 33 Cu 47 Zr 9 Ni 6 Sn 2 Si 1 Nb 2 alloy has been investigated using differential scanning calorimetry and X-ray diffractometry. Partial Nb substitutes for Zr promote the glass forming ability. Ti 33 Cu 47 Zr 9 Ni 6 Sn 2 Si 1 Nb 2 BMG with diameter of 3 mm can be fabricated by Cu-mold injection casting method. The glass forming ability of Ti 33 Cu 47 Zr 9 Ni 6 Sn 2 Si 1 Nb 2 alloy is enhanced by stabilizing the undercooled liquid against crystallization. The plastic strain up to 2.5% was obtained for Ti 33 Cu 47 Zr 9 Ni 6 Sn 2 Si 1 Nb 2 BMG compared to 0.15% for Ti 33 Cu 47 Zr 11 Ni 6 Sn 2 Si 1 BMG, which demonstrates that small amount of Nb addition can have a dramatic effect on plasticity enhancement in Ti-Cu-based BMG. The intersection and branching of the shear bands are observed. The plastic strain of the Ti 33 Cu 47 Zr 9 Ni 6 Sn 2 Si 1 Nb 2 BMG can be improved by the generation of nanocrystalline particles, which lead to multiple shear bands.

  11. FLO11 gene length and transcriptional level affect biofilm-forming ability of wild flor strains of Saccharomyces cerevisiae.

    Science.gov (United States)

    Zara, Giacomo; Zara, Severino; Pinna, Claudia; Marceddu, Salvatore; Budroni, Marilena

    2009-12-01

    In Saccharomyces cerevisiae, FLO11 encodes an adhesin that is associated with different phenotypes, such as adherence to solid surfaces, hydrophobicity, mat and air-liquid biofilm formation. In the present study, we analysed FLO11 allelic polymorphisms and FLO11-associated phenotypes of 20 flor strains. We identified 13 alleles of different lengths, varying from 3.0 to 6.1 kb, thus demonstrating that FLO11 is highly polymorphic. Two alleles of 3.1 and 5.0 kb were cloned into strain BY4742 to compare the FLO11-associated phenotypes in the same genetic background. We show that there is a significant correlation between biofilm-forming ability and FLO11 length both in different and in the same genetic backgrounds. Moreover, we propose a multiple regression model that allows prediction of air-liquid biofilm-forming ability on the basis of transcription levels and lengths of FLO11 alleles in a population of S. cerevisiae flor strains. Considering that transcriptional differences are only partially explained by the differences in the promoter sequences, our results are consistent with the hypothesis that FLO11 transcription levels are strongly influenced by genetic background and affect biofilm-forming ability.

  12. The Transcription Factor Nrf2 Protects Angiogenic Capacity of Endothelial Colony-Forming Cells in High-Oxygen Radical Stress Conditions

    Directory of Open Access Journals (Sweden)

    Hendrik Gremmels

    2017-01-01

    Full Text Available Background. Endothelial colony forming cells (ECFCs have shown a promise in tissue engineering of vascular constructs, where they act as endothelial progenitor cells. After implantation, ECFCs are likely to be subjected to elevated reactive oxygen species (ROS. The transcription factor Nrf2 regulates the expression of antioxidant enzymes in response to ROS. Methods. Stable knockdown of Nrf2 and Keap1 was achieved by transduction with lentiviral shRNAs; activation of Nrf2 was induced by incubation with sulforaphane (SFN. Expression of Nrf2 target genes was assessed by qPCR, oxidative stress was assessed using CM-DCFDA, and angiogenesis was quantified by scratch-wound and tubule-formation assays. Results. Nrf2 knockdown led to a reduction of antioxidant gene expression and increased ROS. Angiogenesis was disturbed after Nrf2 knockdown even in the absence of ROS. Conversely, angiogenesis was preserved in high ROS conditions after knockdown of Keap1. Preincubation of ECFCs with SFN reduced intracellular ROS in the presence of H2O2 and preserved scratch-wound closure and tubule-formation. Conclusion. The results of this study indicate that Nrf2 plays an important role in the angiogenic capacity of ECFCs, particularly under conditions of increased oxidative stress. Pretreatment of ECFCs with SFN prior to implantation may be a protective strategy for tissue-engineered constructs or cell therapies.

  13. [The effects of an aroma candy on oral Candida albicans colony-forming units (CFU) and oral hygiene states in healthy elderly carrying Candida albicans].

    Science.gov (United States)

    Suzuki, Motofumi; Hayama, Kazumi; Takahashi, Miki; Ezawa, Kunio; Yamazaki, Masatoshi; Matsukawa, Taiji; Kishi, Akinobu; Satou, Nobuya; Abe, Shigeru

    2015-01-01

    In a preceding paper, we showed that aroma candy containing oligonol, capric acid, and cinnamon (cassia) powder had potent inhibitory activity against mycelial growth of Candida albicans in vitro and protective activity against murine oral candidiasis. In order to assess the effects of this candy (the test candy) on oral C. albicans colony-forming units (CFU) and oral hygiene states, a placebo-controlled double-blind crossover comparative study was performed. Twenty subjects were divided into two groups. One group ingested the test candy in the first 7 days followed by 2 weeks washing-off period, then ingested the placebo candy (control candy) for 7 days. The other group was vice versa. C. albicans CFU in all oral rinse samples from the subjects before and after 7 days ingestion of candy was measured. The degree of oral malodor in all subjects was monitored using a portable measuring instrument. The results showed no statistically significant difference between test-candy group and placebo group for C. albicans CFU. However, C. albicans CFU in test-candy group with>4,000 CFUs was significantly decreased after 7 days ingestion of test-candy (poral malodor in the test-candy group was significantly decreased after 7 days ingestion of test-candy (poral hygiene states indicated that in the test-candy group, oral malodor, glutinous feeling, and refreshing feeling significantly improved in comparison with control-candy group (poral health care of elderly carrying C. albicans.

  14. Comparative study of 5-fluorouracil and its derivative, N1-(2'-tetrahydrofuryl)-5-fluorouracil on endogenous colony forming units in spleens of mice

    International Nuclear Information System (INIS)

    Ueno, Yori

    1976-01-01

    The effect of intraperitoneal injection of N 1 -(2'-tetrahydrofuryl)-5-fluorouracil (FT-207) which is metabolized to 5-fluorouracil (5-FU) in vivo, on endogeneous colony forming units in the spleen (endogeneous CFU-s) was observed and compared with that of 5-FU. The 8 x 10 -4 m eqv of FT-207 injected in mice 20 minutes before x-rays irradiation of 450 rads suppressed the endogeneous CFU-s count to about 60% and about 5.5 x 10 -5 m eqv of 5-FU had the same effect. The suppression of FT-207 continued over 120 minutes and increased gradually. The effect of 5-FU was strong shortly after the injection but faded out for 120 minutes. FT-207 had almost no effect on the recovery constant (Blair) of endogeneous CFU-s for 3 days, whereas 5-FU reduced seriously, especially for the first 2 days. The differences in the effects of both compounds could not be explained on the base of the only differences in the metabolism of both compounds. (auth.)

  15. Acidic preconditioning of endothelial colony-forming cells (ECFC) promote vasculogenesis under proinflammatory and high glucose conditions in vitro and in vivo.

    Science.gov (United States)

    Mena, Hebe Agustina; Zubiry, Paula Romina; Dizier, Blandine; Schattner, Mirta; Boisson-Vidal, Catherine; Negrotto, Soledad

    2018-05-02

    We have previously demonstrated that acidic preconditioning of human endothelial colony-forming cells (ECFC) increased proliferation, migration, and tubulogenesis in vitro, and increased their regenerative potential in a murine model of hind limb ischemia without baseline disease. We now analyze whether this strategy is also effective under adverse conditions for vasculogenesis, such as the presence of ischemia-related toxic molecules or diabetes, one of the main target diseases for cell therapy due to their well-known healing impairments. Cord blood-derived CD34 + cells were seeded in endothelial growth culture medium (EGM2) and ECFC colonies were obtained after 14-21 days. ECFC were exposed at pH 6.6 (preconditioned) or pH 7.4 (nonpreconditioned) for 6 h, and then pH was restored at 7.4. A model of type 2 diabetes induced by a high-fat and high-sucrose diet was developed in nude mice and hind limb ischemia was induced in these animals by femoral artery ligation. A P value < 0.05 was considered statistically significant (by one-way analysis of variance). We found that acidic preconditioning increased ECFC adhesion and the release of pro-angiogenic molecules, and protected ECFC from the cytotoxic effects of monosodium urate crystals, histones, and tumor necrosis factor (TNF)α, which induced necrosis, pyroptosis, and apoptosis, respectively. Noncytotoxic concentrations of high glucose, TNFα, or their combination reduced ECFC proliferation, stromal cell-derived factor (SDF)1-driven migration, and tubule formation on a basement membrane matrix, whereas almost no inhibition was observed in preconditioned ECFC. In type 2 diabetic mice, intravenous administration of preconditioned ECFC significantly induced blood flow recovery at the ischemic limb as measured by Doppler, compared with the phosphate-buffered saline (PBS) and nonpreconditioned ECFC groups. Moreover, the histologic analysis of gastrocnemius muscles showed an increased vascular density and reduced

  16. The glass-forming ability of model metal-metalloid alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Kai; Liu, Yanhui; Schroers, Jan [Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520 (United States); Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520 (United States); Shattuck, Mark D. [Department of Physics and Benjamin Levich Institute, The City College of the City University of New York, New York, New York 10031 (United States); Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520 (United States); O’Hern, Corey S. [Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520 (United States); Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520 (United States); Department of Physics, Yale University, New Haven, Connecticut 06520 (United States); Department of Applied Physics, Yale University, New Haven, Connecticut 06520 (United States)

    2015-03-14

    Bulk metallic glasses (BMGs) are amorphous alloys with desirable mechanical properties and processing capabilities. To date, the design of new BMGs has largely employed empirical rules and trial-and-error experimental approaches. Ab initio computational methods are currently prohibitively slow to be practically used in searching the vast space of possible atomic combinations for bulk glass formers. Here, we perform molecular dynamics simulations of a coarse-grained, anisotropic potential, which mimics interatomic covalent bonding, to measure the critical cooling rates for metal-metalloid alloys as a function of the atomic size ratio σ{sub S}/σ{sub L} and number fraction x{sub S} of the metalloid species. We show that the regime in the space of σ{sub S}/σ{sub L} and x{sub S} where well-mixed, optimal glass formers occur for patchy and LJ particle mixtures, coincides with that for experimentally observed metal-metalloid glass formers. Thus, our simple computational model provides the capability to perform combinatorial searches to identify novel glass-forming alloys.

  17. The effects of mycoplasma contamination upon the ability to form bioengineered 3D kidney cysts.

    Directory of Open Access Journals (Sweden)

    Teresa M DesRochers

    Full Text Available Mycoplasma contamination of cell cultures is a pervasive, often undiagnosed and ignored problem in many laboratories that can result in reduced cell proliferation and changes in gene expression. Unless contamination is specifically suspected, it is often undetected in two dimensional (2D cultures and the resulting effects of mycoplasma contamination are rarely appreciated and can lead to incorrect conclusions. Three dimensional (3D tissue cultures are increasingly utilized to explore tissue development and phenotype. However, 3D cultures are more complex than 2D cell cultures and require a more controlled cellular environment in order to generate structures necessary to mimic in vivo responses and are often maintained for longer time periods. Changes to the microenvironment are assumed to have a more extreme effect upon the success of 3D tissue cultures than 2D cell cultures, but the effects of mycoplasma have not been studied. To test this hypothesis, we grew 2D cell cultures and 3D tissues from pig kidney epithelial cells (LLC-PK1 that were contaminated with mycoplasma and the same stock of cells after mycoplasma removal. We did not observe an effect of mycoplasma contamination on proliferation in 2D monolayer cell culture. However, cyst formation in 3D tissues was altered, with effects upon the number, size and structure of cysts formed. These data serve to reinforce the necessity of testing cell stocks for mycoplasma contamination.

  18. Colony Dimorphism in Bradyrhizobium Strains

    Science.gov (United States)

    Sylvester-Bradley, Rosemary; Thornton, Philip; Jones, Peter

    1988-01-01

    Ten isolates of Bradyrhizobium spp. which form two colony types were studied; the isolates originated from a range of legume species. The two colony types differed in the amount of gum formed or size or both, depending on the strain. Whole 7-day-old colonies of each type were subcultured to determine the proportion of cells which had changed to the other type. An iterative computerized procedure was used to determine the rate of switching per generation between the two types and to predict proportions reached at equilibrium for each strain. The predicted proportions of the wetter (more gummy) or larger colony type at equilibrium differed significantly between strains, ranging from 0.9999 (strain CIAT 2383) to 0.0216 (strain CIAT 2469), because some strains switched faster from dry to wet (or small to large) and others switched faster from wet to dry (or large to small). Predicted equilibrium was reached after about 140 generations in strain USDA 76. In all but one strain (CIAT 3030) the growth rate of the wetter colony type was greater than or similar to that of the drier type. The mean difference in generation time between the two colony types was 0.37 h. Doubling times calculated for either colony type after 7 days of growth on the agar surface ranged from 6.0 to 7.3 h. The formation of two persistent colony types by one strain (clonal or colony dimorphism) may be a common phenomenon among Bradyrhizobium strains. Images PMID:16347599

  19. Human endothelial colony-forming cells expanded with an improved protocol are a useful endothelial cell source for scaffold-based tissue engineering.

    Science.gov (United States)

    Denecke, Bernd; Horsch, Liska D; Radtke, Stefan; Fischer, Johannes C; Horn, Peter A; Giebel, Bernd

    2015-11-01

    One of the major challenges in tissue engineering is to supply larger three-dimensional (3D) bioengineered tissue transplants with sufficient amounts of nutrients and oxygen and to allow metabolite removal. Consequently, artificial vascularization strategies of such transplants are desired. One strategy focuses on endothelial cells capable of initiating new vessel formation, which are settled on scaffolds commonly used in tissue engineering. A bottleneck in this strategy is to obtain sufficient amounts of endothelial cells, as they can be harvested only in small quantities directly from human tissues. Thus, protocols are required to expand appropriate cells in sufficient amounts without interfering with their capability to settle on scaffold materials and to initiate vessel formation. Here, we analysed whether umbilical cord blood (CB)-derived endothelial colony-forming cells (ECFCs) fulfil these requirements. In a first set of experiments, we showed that marginally expanded ECFCs settle and survive on different scaffold biomaterials. Next, we improved ECFC culture conditions and developed a protocol for ECFC expansion compatible with 'Good Manufacturing Practice' (GMP) standards. We replaced animal sera with human platelet lysates and used a novel type of tissue-culture ware. ECFCs cultured under the new conditions revealed significantly lower apoptosis and increased proliferation rates. Simultaneously, their viability was increased. Since extensively expanded ECFCs could still settle on scaffold biomaterials and were able to form tubular structures in Matrigel assays, we conclude that these ex vivo-expanded ECFCs are a novel, very potent cell source for scaffold-based tissue engineering. Copyright © 2013 John Wiley & Sons, Ltd.

  20. Synthesis, structure and complex forming ability of phosphorylated derivatives of heterocyclic compounds

    International Nuclear Information System (INIS)

    Babaev, B.N.

    2004-01-01

    Full text: The derivatives of acids of phosphorus, due to variety of properties, are a subject of numerous researches. Now it is known, that the derivatives of acids of phosphorus apart from insect, neurotoxic, antienzym and other kinds of physiological activity have also complex forming properties. As extra gents of noble metals particularly are analyzed by the derivatives of dithio phosphor of acids although organ phosphorus compounds with one nuclear of sulfur make extraction properties. Therefore, with the purpose of detection of effective extra gents of ions of argentum the phosphorylated derivatives of heterogeneous ring compounds were synthesized: Ph(RO)P(O)Cl + HOCH(CH 3 )CH 2 -R ' -> Ph(RO)P(O)OCH(CH 3 )CH 2 -R ' + HCl. R C 2 H 5 - C 6 H 13 , R ' = a piperidine, morpholine, anabasine Structure of the obtained connections is confirmed by the results IR -, Pm- and mass- spectrometry. In an IR-spectrum O-hexyl-O - [piperidynoisopropyl] phenylphosphonate has lines of absorption bands of the following functional groups (ν, cm -1 ): (P-O-C 5 H 11 ) 990-1000, (P = 0) 1260, (P-C 6 H 5 )1450, (C-N in cycle) 1550. In an IR-spectrum O-pentyl-[anabasinoisopropyl] phenylphosphonate has lines of absorption bands of the following functional groups (ν, cm -1 ): (P-O-C 5 H 11 ) 990-1000, (P = 0) 1250, (P-C 6 H 5 )1450, (C-N in cycle) 1550. In a spectrum PMR about O-pentyl-[morpholyniisopropyl] phenylphosphonate in the field of a weak field (7, 18-7, 29 p.m.) the multiplet about tones of phenyl group is watched. Me tin proton resonate at 4,66 m.d.as multiplet The signals O-CH 2 of protons of morpholinic cycle appear at 3,58 m.d.. 4H) by the way of triplet. The protons N-CH 2 (6H) three methylene groups will derivate a composite multiple at 2, 10-2, 70 m.d.. The signal of metil group's protons (3H) is watched at 1,15m.d.as doublet. Final metal group resonates at 0, 87 p.m. Six of C-CH 2 of groups give a complex signal in the field of 1, 2-1, 8 m.d. The obtained connections

  1. Enhanced glass forming ability and refrigerant capacity of a Gd55Ni22Mn3Al20 bulk metallic glass

    International Nuclear Information System (INIS)

    Xia, L.; Chan, K.C.; Tang, M.B.

    2011-01-01

    Highlights: → A new Gd 55 Ni 22 Mn 3 Al 20 bulk metallic glass (BMG) was synthesized by minor Mn addition. → The BMG has enhanced glass forming ability and excellent refrigerant capacity (RC). → The RC of the BMG reaches a high value of 825 J kg -1 under a field of 3979 kA/m. → Its excellent RC is related to its large effective magnetic moment. - Abstract: In this work, a small amount of Mn was added to a Gd 55 Ni 25 Al 20 glass forming alloy, as a replacement for Ni, and a Gd 55 Ni 22 Mn 3 Al 20 bulk metallic glass (BMG) was obtained by suction casting. Its glass forming ability (GFA) was characterized by X-ray diffraction and differential scanning calorimetry, and its magnetic properties were measured using a magnetic property measurement system. It is found that the minor Mn addition can significantly improve both the GFA and the magnetocaloric effect (MCE) of the alloy. The refrigerant capacity (RC) of the BMG can reach a high value of 825 J kg -1 under a field of 3979 kA/m, which is about 29% larger than that of a Gd 55 Ni 25 Al 20 BMG. The effect of the minor Mn addition on the GFA and MCE of the BMG was investigated in the study.

  2. Investigating the atomic level influencing factors of glass forming ability in NiAl and CuZr metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Sedighi, Sina; Kirk, Donald Walter; Singh, Chandra Veer, E-mail: chandraveer.singh@utoronto.ca; Thorpe, Steven John [Department of Materials Science and Engineering, University of Toronto, Room 140, 184 College Street, Toronto, Ontario M5S 3E4 (Canada)

    2015-09-21

    Bulk metallic glasses are a relatively new class of amorphous metal alloy which possess unique mechanical and magnetic properties. The specific concentrations and combinations of alloy elements needed to prevent crystallization during melt quenching remains poorly understood. A correlation between atomic properties that can explain some of the previously identified glass forming ability (GFA) anomalies of the NiAl and CuZr systems has been identified, with these findings likely extensible to other transition metal–transition metal and transition metal–metalloid (TM–M) alloy classes as a whole. In this work, molecular dynamics simulation methods are utilized to study thermodynamic, kinetic, and structural properties of equiatomic CuZr and NiAl metallic glasses in an attempt to further understand the underlying connections between glass forming ability, nature of atomic level bonding, short and medium range ordering, and the evolution of structure and relaxation properties in the disordered phase. The anomalous breakdown of the fragility parameter as a useful GFA indicator in TM–M alloy systems is addressed through an in-depth investigation of bulk stiffness properties and the evolution of (pseudo)Gruneisen parameters over the quench domain, with the efficacy of other common glass forming ability indicators similarly being analyzed through direct computation in respective CuZr and NiAl systems. Comparison of fractional liquid-crystal density differences in the two systems revealed 2-3 times higher values for the NiAl system, providing further support for its efficacy as a general purpose GFA indicator.

  3. High frequency of endothelial colony forming cells marks a non-active myeloproliferative neoplasm with high risk of splanchnic vein thrombosis.

    Directory of Open Access Journals (Sweden)

    Vittorio Rosti

    Full Text Available Increased mobilization of circulating endothelial progenitor cells may represent a new biological hallmark of myeloproliferative neoplasms. We measured circulating endothelial colony forming cells (ECFCs in 106 patients with primary myelofibrosis, fibrotic stage, 49 with prefibrotic myelofibrosis, 59 with essential thrombocythemia or polycythemia vera, and 43 normal controls. Levels of ECFC frequency for patient's characteristics were estimated by using logistic regression in univariate and multivariate setting. The sensitivity, specificity, likelihood ratios, and positive predictive value of increased ECFC frequency were calculated for the significantly associated characteristics. Increased frequency of ECFCs resulted independently associated with history of splanchnic vein thrombosis (adjusted odds ratio = 6.61, 95% CI = 2.54-17.16, and a summary measure of non-active disease, i.e. hemoglobin of 13.8 g/dL or lower, white blood cells count of 7.8×10(9/L or lower, and platelet count of 400×10(9/L or lower (adjusted odds ratio = 4.43, 95% CI = 1.45-13.49 Thirteen patients with splanchnic vein thrombosis non associated with myeloproliferative neoplasms were recruited as controls. We excluded a causal role of splanchnic vein thrombosis in ECFCs increase, since no control had elevated ECFCs. We concluded that increased frequency of ECFCs represents the biological hallmark of a non-active myeloproliferative neoplasm with high risk of splanchnic vein thrombosis. The recognition of this disease category copes with the phenotypic mimicry of myeloproliferative neoplasms. Due to inherent performance limitations of ECFCs assay, there is an urgent need to arrive to an acceptable standardization of ECFC assessment.

  4. The ability to form full-length intron RNA circles is a general property of nuclear group I introns

    DEFF Research Database (Denmark)

    Nielsen, Henrik; Fiskaa, Tonje; Birgisdottir, Asa Birna

    2003-01-01

    at the expense of the host. The circularization pathway has distinct structural requirements that differ from those of splicing and appears to be specifically suppressed in vivo. The ability to form full-length circles is found in all types of nuclear group I introns, including those from the Tetrahymena...... ribosomal DNA. The biological function of the full-length circles is not known, but the fact that the circles contain the entire genetic information of the intron suggests a role in intron mobility....

  5. Thermodynamic and topological instability approaches for forecasting glass-forming ability in the ternary Al-Ni-Y system

    International Nuclear Information System (INIS)

    Oliveira, M.F. de; Aliaga, L.C.R.; Bolfarini, C.; Botta, W.J.; Kiminami, C.S.

    2008-01-01

    A thermodynamic approach to predict bulk glass-forming compositions in binary metallic systems was recently proposed. In this approach, the parameter γ* = ΔH amor /(ΔH inter - ΔH amor ) indicates the glass-forming ability (GFA) from the standpoint of the driving force to form different competing phases, and ΔH amor and ΔH inter are the enthalpies for glass and intermetallic formation, respectively. Good glass-forming compositions should have a large negative enthalpy for glass formation and a very small difference for intermetallic formation, thus making the glassy phase easily reachable even under low cooling rates. The γ* parameter showed a good correlation with GFA experimental data in the Ni-Nb binary system. In this work, a simple extension of the γ* parameter is applied in the ternary Al-Ni-Y system. The calculated γ* isocontours in the ternary diagram are compared with experimental results of glass formation in that system. Despite some misfitting, the best glass formers are found quite close to the highest γ* values, leading to the conclusion that this thermodynamic approach can be extended to ternary systems, serving as a useful tool for the development of new glass-forming compositions. Finally the thermodynamic approach is compared with the topological instability criteria used to predict the thermal behavior of glassy Al alloys

  6. Influence of Y, Gd and Sm on the glass forming ability and thermal crystallization of aluminum based alloy

    International Nuclear Information System (INIS)

    Aliaga, L.C.R.; Bolfarini, C.; Kiminami, C.S.; Botta Filho, W.J.; Danez, G.P.

    2010-01-01

    Al-based amorphous alloys represent an important family of metals and a great scientific activity has been devoted to determine the main features of both glass forming ability (GFA) and crystallization behavior in order to have a comprehensive framework aimed at potential technological applications. Nowadays, it is well known that the best Al-based amorphous alloys are formed in ternary systems such as Al- RE-TM, where RE is a rare earth and TM a transition metal. This paper presents results of research in Al 85 Ni 10 RE 5 alloys (RE = Y, Gd and Sm). Amorphous ribbons were processed by melt-spinning under the same conditions and subsequently characterized by x-ray diffraction (XRD) and differential scanning calorimetry (DSC). Results show appreciable micro structural differences as function of the rare earth, thus crystal is obtained for Y, nano-glassy for Gd and, fully amorphous structure for Sm. (author)

  7. The Endospore-Forming Pathogen Bacillus cereus Exploits a Small Colony Variant-Based Diversification Strategy in Response to Aminoglycoside Exposure.

    Science.gov (United States)

    Frenzel, Elrike; Kranzler, Markus; Stark, Timo D; Hofmann, Thomas; Ehling-Schulz, Monika

    2015-12-08

    Bacillus cereus is among the microorganisms most often isolated from cases of food spoilage and causes gastrointestinal diseases as well as nongastrointestinal infections elicited by the emetic toxin cereulide, enterotoxins, and a panel of tissue-destructive virulence factors. This opportunistic pathogen is increasingly associated with rapidly fatal clinical infections especially linked to neonates and immunocompromised individuals. Fatality results from either the misdiagnosis of B. cereus as a contaminant of the clinical specimen or from failure of antibiotic therapy. Here we report for the first time that exposure to aminoglycoside antibiotics induces a phenotype switching of emetic B. cereus subpopulations to a slow-growing small colony variant (SCV) state. Along with altered antibiotic resistance, SCVs showed distinct phenotypic and metabolic properties, bearing the risk of antibiotic treatment failure and of clinical misdiagnosis by standard identification tests used in routine diagnostic. The SCV subpopulation is characterized by enhanced production of the toxin cereulide, but it does not secrete tissue-destructive and immune system-affecting enzymes such as sphingomyelinase and phospholipase. SCVs showed significantly prolonged persistence and decreased virulence in the Galleria mellonella model for bacterial infections, indicating diversification concerning their ecological lifestyle. Importantly, diversification into coexisting wild-type and SCV subpopulations also emerged during amikacin pressure during in vivo infection experiments. This study shows for the first time that pathogenic spore-forming B. cereus strains are able to switch to a so far unreported slow-growing lifestyle, which differs substantially in terms of developmental, phenotypic, metabolic, and virulence traits from the wild-type populations. This underpins the necessity of molecular-based differential diagnostics and a well-chosen therapeutic treatment strategy in clinical

  8. Effect of Ga substitution on the crystallization behaviour and glass forming ability of Zr-Al-Cu-Ni alloys

    International Nuclear Information System (INIS)

    Singh, Devinder; Yadav, T.P.; Mandal, R.K.; Tiwari, R.S.; Srivastava, O.N.

    2010-01-01

    The crystallization behaviour of melt spun Zr 69.5 Al 7.5-x Ga x Cu 12 Ni 11 (x = 0-7.5; in at.%) metallic glasses has been investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). The DSC traces showed changes in crystallization behaviour with substitution of Ga. Formation of single nano-quasicrystalline phase by controlled crystallization of glasses has been found only for 0 ≤ x ≤ 1.5. Further increase of Ga content gives rise to formation of the quasicrystals together with Zr 2 Cu type crystalline phase. In addition to this, the substitution of Ga influences the size and shape of nano-quasicrystals. The glass forming abilities (GFAs) of these metallic glasses were assessed by the recognition of glass forming ability indicators, i.e. reduced glass transition temperature (T rg ) and supercooled liquid region (ΔT x ). The glass transition temperature (T g ) has been observed for all the melt spun ribbons.

  9. Physical stability of drugs after storage above and below the glass transition temperature: Relationship to glass-forming ability.

    Science.gov (United States)

    Alhalaweh, Amjad; Alzghoul, Ahmad; Mahlin, Denny; Bergström, Christel A S

    2015-11-10

    Amorphous materials are inherently unstable and tend to crystallize upon storage. In this study, we investigated the extent to which the physical stability and inherent crystallization tendency of drugs are related to their glass-forming ability (GFA), the glass transition temperature (Tg) and thermodynamic factors. Differential scanning calorimetry was used to produce the amorphous state of 52 drugs [18 compounds crystallized upon heating (Class II) and 34 remained in the amorphous state (Class III)] and to perform in situ storage for the amorphous material for 12h at temperatures 20°C above or below the Tg. A computational model based on the support vector machine (SVM) algorithm was developed to predict the structure-property relationships. All drugs maintained their Class when stored at 20°C below the Tg. Fourteen of the Class II compounds crystallized when stored above the Tg whereas all except one of the Class III compounds remained amorphous. These results were only related to the glass-forming ability and no relationship to e.g. thermodynamic factors was found. The experimental data were used for computational modeling and a classification model was developed that correctly predicted the physical stability above the Tg. The use of a large dataset revealed that molecular features related to aromaticity and π-π interactions reduce the inherent physical stability of amorphous drugs. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Atomistic approach to predict the glass-forming ability in Zr–Cu–Al ternary metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Yu, C.Y. [Center for Advanced Structural Materials, Department of Mechanical and Biomedical Engineering, College of Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong (China); Liu, X.J. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Zheng, G.P. [Department of Mechanical Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong (China); Niu, X.R. [Center for Advanced Structural Materials, Department of Mechanical and Biomedical Engineering, College of Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong (China); Liu, C.T., E-mail: chainliu@cityu.edu.hk [Center for Advanced Structural Materials, Department of Mechanical and Biomedical Engineering, College of Science and Engineering, City University of Hong Kong, Kowloon, Hong Kong (China)

    2015-04-05

    Highlights: • An atomistic approach has been developed to predict the glass forming ability (GFA) in Zr–Cu–Al ternary alloy system. • Both of the thermodynamic and structure-dependent kinetic effects to glass formation have been taken into account. • The first-principles calculation and molecular dynamics simulation have been performed. • The approach predicts the best glass former in the model Zr–Cu–Al alloy system. • The predicted GFA is consistent with various experimental results. - Abstract: Prediction of composition-dependent glass-forming ability (GFA) remains to be a key scientific challenge in the metallic-glass community, especially in multi-component alloy systems. In the present study, we apply an atomistic approach to predict the trend of GFA effectively in the Zr–Cu–Al ternary alloy system from alloy compositions alone. This approach is derived from the first-principles calculations based on the density-functional theory and molecular dynamic (MD) simulations. By considering of both the thermodynamic and atomic-structure induced kinetic effects, the predicted GFA trend from this approach shows an excellent agreement with experimental data available in this alloy system, manifesting its capability of seeking metallic glasses with superior GFA in ternary alloy systems.

  11. A new Ti-Zr-Hf-Cu-Ni-Si-Sn bulk amorphous alloy with high glass-forming ability

    International Nuclear Information System (INIS)

    Huang, Y.J.; Shen, J.; Sun, J.F.; Yu, X.B.

    2007-01-01

    The effect of Sn substitution for Cu on the glass-forming ability was investigated in Ti 41.5 Zr 2.5 Hf 5 Cu 42.5-x Ni 7.5 Si 1 Sn x (x = 0, 1, 3, 5, 7) alloys by using differential scanning calorimetry (DSC) and X-ray diffractometry. The alloy containing 5% Sn shows the highest glass-forming ability (GFA) among the Ti-Zr-Hf-Cu-Ni-Si-Sn system. Fully amorphous rod sample with diameters up to 6 mm could be successfully fabricated by the copper mold casting Ti 41.5 Zr 2.5 Hf 5 Cu 37.5 Ni 7.5 Si 1 Sn 5 alloy. The activation energies for glass transition and crystallization for Ti 41.5 Zr 2.5 Hf 5 Cu 37.5 Ni 7.5 Si 1 Sn 5 amorphous alloy are both larger than those values for the Sn-free alloy. The enhancement in GFA and thermal stability after the partial replacement of Cu by Sn may be contributed to the strong atomic bonding nature between Ti and Sn and the increasing of atomic packing density. The amorphous Ti 41.5 Zr 2.5 Hf 5 Cu 37.5 Ni 7.5 Si 1 Sn 5 alloy also possesses superior mechanical properties

  12. Copper oxide content dependence of crystallization behavior, glass forming ability, glass stability and fragility of lithium borate glasses

    International Nuclear Information System (INIS)

    Soliman, A.A.; Kashif, I.

    2010-01-01

    Differential thermal analysis (DTA) and X-ray diffraction (XRD) have been employed to investigate the copper oxide content dependence of the glass transition temperatures data, activation energy for the glass transition E t , glass stability GS, fragility index Fi, the glass-forming ability (GFA) and crystallization behavior of {(100-x) mol% Li 2 B 4 O 7 -x mol% CuO} glass samples, where x=0-40 mol% CuO. From the dependence of the glass transition temperature T g on the heating rate β, the fragility, F i , and the activation energy, E t , have been calculated. It is seen that F i and E t are attained their minimum values at 0 x -T g , SCL region and the GS. The GFA has been investigated on the basis of Hruby parameter K H , which is a strong indicator of GFA, and the relaxation time. Results of GFA are in good agreement with the fragility index, F i , calculations indicating that {90Li 2 B 4 O 7 .10CuO} is the best glass former. The stronger glass forming ability has decreasing the fragility index. XRD result indicates that no fully amorphous samples but a mixture of crystalline and amorphous phases are formed in the samples containing x>25 mol% CuO and below it composed of glassy phase. Increasing the CuO content above 25 mol% helps the crystallization process, and thus promotes a distinct SCL region. XRD suggests the presence of micro-crystallites of remaining residual amorphous matrix by increasing the CuO content.

  13. Do different standard plate counting (IDF/ISSO or AOAC) methods interfere in the conversion of individual bacteria counts to colony forming units in raw milk?

    Science.gov (United States)

    Cassoli, L D; Lima, W J F; Esguerra, J C; Da Silva, J; Machado, P F; Mourão, G B

    2016-10-01

    This study aimed to establish the correlation between individual bacterial count (IBC) obtained by flow cytometry and the number of colony forming units (CFU) determined by standard plate count (SPC) in raw milk using two different reference methodologies: the methodology of the International Dairy Federation (IDF) - International Organization for Standardization (ISO) 4833, incubation for 72 h at 30°C and the methodology of the Association of Official Analytical Chemists (AOAC), incubation for 48 h at 35°C. For this, 100 bovine milk samples (80 ml) from different farms were collected in a sterile bottle and maintained refrigerated at 4°C and were delivered to the laboratory. In the laboratory, the samples were divided into two vials of 40 ml each. Then, half of the vials were forwarded for the SPC analysis, and the other half were analysed using the equipment BactoScan FC. The analyses by flow cytometry and SPC were performed at the same time (maximum deviation of +/- 1 h). To transform the data from IBC ml(-1) to CFU ml(-1) (IDF or AOAC methodology), a standard linear regression equation was used, as recommended by IDF/ISO-196. The difference between the reference methodologies affects the equation that transforms IBC into CFU and therefore the accuracy of the results. The results estimated by the equation using the ISO 4833 methodology were on average 0·18 log units higher than the results estimated using the equation using the AOAC methodology. After the comparison of the methodologies, it was concluded that there is an impact of the reference methodologies on the conversion of the results from IBC to CFU. Depending on the methodology adopted by each laboratory or country, there may not be equivalence in the results. Hence, the laboratories specialized in milk quality analysis that have changed their methodology for analysis, passing from the MAPA (AOAC) methodology to the IDF standard, need to develop new conversion equations to make their

  14. Glass-Forming Ability and Early Crystallization Kinetics of Novel Cu-Zr-Al-Co Bulk Metallic Glasses

    Directory of Open Access Journals (Sweden)

    Xiaoliang Han

    2016-09-01

    Full Text Available In recent years, CuZr-based bulk metallic glass (BMG composites ductilized by a shape memory B2 CuZr phase have attracted great attention owing to their outstanding mechanical properties. However, the B2 CuZr phase for most CuZr-based glass-forming compositions is only stable at very high temperatures, leading to the uncontrollable formation of B2 crystals during quenching. In this work, by introducing Co (i.e., 4, 5, and 6 at. % and 10 at. % Al into CuZr-based alloys, the relatively good glass-forming ability (GFA of CuZr-based alloys still can be achieved. Meanwhile, the B2 phase can be successfully stabilized to lower temperatures than the final temperatures of crystallization upon heating CuZr-based BMGs. Unlike previous reported CuZr-based BMGs, the primary crystallization products upon heating are mainly B2 CuZr crystals but not CuZr2 and Cu10Zr7 crystals. Furthermore, the primary precipitates during solidification are still dominated by B2 crystals, whose percolation threshold is detected to lie between 10 ± 2 vol. % and 31 ± 2 vol. %. The crystallization kinetics underlying the precipitation of B2 crystals was also investigated. Our results show that the present glass-forming composites are promising candidates for the fabrication of ductile CuZr-based BMG composites.

  15. Composition dependency of the glass forming ability (GFA) in Mg-Ni-Si system by mechanical alloying

    International Nuclear Information System (INIS)

    Xie Haowen; Lin Jianguo; Li Yuncang; Hodgson, Peter D.; Wen Cuie

    2007-01-01

    The pure elemental powder mixtures with the compositions of Mg 65 Ni x Si 35-x (x = 10, 20, 25, 33 at.%) were subject to high-energy ball mill, and the structures of the mixtures at different intervals of milling were characterised by X-ray diffraction (XRD). The compositional dependency of the glass forming ability (GFA) in Mg-Ni-Si system was evaluated based on the experimental results and the theoretical calculation. The compositional dependency of GFA in Mg-Ni-Si system can be understood well by comparing the enthalpies of the crystalline and amorphous phases based on the Miedema's theory for the formation enthalpy of alloys. Increasing the Ni/Mg ratio and/or decreasing Si content can improve the amorphous formability. The calculation results might be of great help in optimising the composition with high GFA in Mg-Ni-Si system

  16. Influence of minor alloying additions on the glass-forming ability of Mg-Ni-La bulk metallic glasses

    International Nuclear Information System (INIS)

    Gonzalez, S.; Figueroa, I.A.; Todd, I.

    2009-01-01

    Bulk metallic glasses of Mg 60 Ni 23.6 Y x La (16.4-x) and Mg 65 Ni 20 Y x LaMM (15-x) with 0 ≤ x ≤ 1 at.% have been produced by injection casting. For the La-containing alloy a maximum amorphous diameter of 4 mm for x = 0.5 and 0.75 was obtained. The LaMM-containing alloy showed a maximum amorphous diameter of 2 mm for x = 0 and 0.25 but decreased to 1 mm with further Y additions. The glass-forming ability of the Mg 60 Ni 23.6 La 16.4 alloy decreased when La is partially substituted by small amounts of small atoms (Si or B) or by large atoms (Y and Si).

  17. Effect of histatin-5 and lysozyme on the ability of Streptococcus mutans to form biofilms in in vitro conditions.

    Science.gov (United States)

    Krzyściak, Wirginia; Jurczak, Anna; Piątkowski, Jakub; Kościelniak, Dorota; Gregorczyk-Maga, Iwona; Kołodziej, Iwona; Papież, Monika A; Olczak-Kowalczyk, Dorota

    2015-09-20

    The mechanisms of adhesion to solid surfaces enable S. mutans to colonize oral cavities and form biofilms, which play an important role in caries development. Additional properties enabling the survival of S. mutans in the oral cavity include its ability to survive in acidic environments and specific interactions with other microorganisms inhabiting this ecosystem. The aim of this study was to determine the antibacterial activity of saliva histatin-5 (peptide) and lysozyme (protein) against S. mutans and L. rhamnosus, as representatives of physiological flora. The study involved strains of physiological (L. rhamnosus) and cariogenic (S. mutans) flora isolated from one patient with diagnosed early caries of the deciduous teeth. It was proved that the presence of probiotic L. rhamnosus bacteria in the environment had a negative impact on the ability of S. mutans to produce biofilm. Moreover, the antibacterial activity of histatin-5 was confirmed, and it inhibited S. mutans growth at concentrations of 27.2 μg/ml and 54.4 μg/ml, both individually and in a mixture with lysozyme (in a total concentration of 54.4 μg/ml). The data obtained constitute a promising result due to their potential future application in the prevention and early diagnosis of caries.

  18. Effect of histatin-5 and lysozyme on the ability of Streptococcus mutans to form biofilms in in vitro conditions

    Directory of Open Access Journals (Sweden)

    Wirginia Krzyściak

    2015-09-01

    Full Text Available The mechanisms of adhesion to solid surfaces enable S. mutans to colonize oral cavities and form biofilms, which play an important role in caries development. Additional properties enabling the survival of S. mutans in the oral cavity include its ability to survive in acidic environments and specific interactions with other microorganisms inhabiting this ecosystem.The aim of this study was to determine the antibacterial activity of saliva histatin-5 (peptide and lysozyme (protein against S. mutans and L. rhamnosus, as representatives of physiological flora.The study involved strains of physiological (L. rhamnosus and cariogenic (S. mutans flora isolated from one patient with diagnosed early caries of the deciduous teeth.It was proved that the presence of probiotic L. rhamnosus bacteria in the environment had a negative impact on the ability of S. mutans to produce biofilm. Moreover, the antibacterial activity of histatin-5 was confirmed, and it inhibited S. mutans growth at concentrations of 27.2 μg/ml and 54.4 μg/ml, both individually and in a mixture with lysozyme (in a total concentration of 54.4 μg/ml.The data obtained constitute a promising result due to their potential future application in the prevention and early diagnosis of caries.

  19. A new Ti-Zr-Hf-Cu-Ni-Si-Sn bulk amorphous alloy with high glass-forming ability

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Y.J. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Shen, J. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China)]. E-mail: junshen@hit.edu.cn; Sun, J.F. [School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001 (China); Yu, X.B. [Lab of Energy Science and Technology, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)]. E-mail: yuxuebin@hotmail.com

    2007-01-16

    The effect of Sn substitution for Cu on the glass-forming ability was investigated in Ti{sub 41.5}Zr{sub 2.5}Hf{sub 5}Cu{sub 42.5-x}Ni{sub 7.5}Si{sub 1}Sn {sub x} (x = 0, 1, 3, 5, 7) alloys by using differential scanning calorimetry (DSC) and X-ray diffractometry. The alloy containing 5% Sn shows the highest glass-forming ability (GFA) among the Ti-Zr-Hf-Cu-Ni-Si-Sn system. Fully amorphous rod sample with diameters up to 6 mm could be successfully fabricated by the copper mold casting Ti{sub 41.5}Zr{sub 2.5}Hf{sub 5}Cu{sub 37.5}Ni{sub 7.5}Si{sub 1}Sn{sub 5} alloy. The activation energies for glass transition and crystallization for Ti{sub 41.5}Zr{sub 2.5}Hf{sub 5}Cu{sub 37.5}Ni{sub 7.5}Si{sub 1}Sn{sub 5} amorphous alloy are both larger than those values for the Sn-free alloy. The enhancement in GFA and thermal stability after the partial replacement of Cu by Sn may be contributed to the strong atomic bonding nature between Ti and Sn and the increasing of atomic packing density. The amorphous Ti{sub 41.5}Zr{sub 2.5}Hf{sub 5}Cu{sub 37.5}Ni{sub 7.5}Si{sub 1}Sn{sub 5} alloy also possesses superior mechanical properties.

  20. Number of colony forming units in urine at 35–37 weeks’ gestation as predictor of the vaginal load of Group B Streptococci at birth

    DEFF Research Database (Denmark)

    Khalil, Mohammad; Bak Thorsen, Poul; Møller, Jens Kjølseth

    2018-01-01

    prophylaxis; NPV, Negative predictive value; PCR, Polymerase chain reaction; PPV, Positive predictive value Keywords Group B Streptococcus bacteriuria; Colony count; Vaginal colonization; Risk factor; Intrapartum colonization; Early-onset neonatal infection; Intrapartum antibiotic prophylaxis...... at 35-37 weeks’ gestation. Outcome was vaginal GBS colonization at birth as assessed by a semi-quantitative culture of a vaginal swab sample (negative, +1, +2, +3). Results Bacteriuria with GBS at 35-37 weeks’ gestation performed with a sensitivity of 30% concerning any degree of vaginal GBS...... colonization at birth (31 of 104 cases); 19% for light (+1), 17% for medium (+2), and 52% for high load (+3) vaginal GBS colonization. The colony count in case of GBS bacteriuria at 35-37 weeks’ gestation performed with positive predictive values of 35% for 104 CFU...

  1. Glass-forming ability and stability of ternary Ni-early transition metal (Ti/Zr/Hf) alloys

    Energy Technology Data Exchange (ETDEWEB)

    Basu, Joysurya [Department of Metallurgy, Indian Institute of Science, Bangalore 560 012 (India); Ranganathan, S. [Department of Metallurgy, Indian Institute of Science, Bangalore 560 012 (India)]. E-mail: rangu@met.iisc.ernet.in

    2006-08-15

    Four Ni-bearing Ti, Zr and Hf ternary alloys of nominal composition Zr{sub 41.5}Ti{sub 41.5}Ni{sub 17}, Zr{sub 25}Ti{sub 25}Ni{sub 50}, Zr{sub 41.5}Hf{sub 41.5}Ni{sub 17} and Ti{sub 41.5}Hf{sub 41.5}Ni{sub 17} were rapidly solidified in order to produce ribbons. The Zr-Ti-Ni and Ti-Hf-Ni alloys become amorphous, whereas the Zr-Hf-Ni alloy shows precipitation of a cubic phase. The devitrification of all three alloys was followed and the relative tendency to form nanoquasicrystals and cF96 phases analysed. The relative glass-forming ability of the alloys can be explained by taking into account their atomic size difference. Addition of Ni often leads to quasicrystallisation or quasicrystal-related phases. This can be explained by the atomic radius and heat of mixing of the constituent elements. The phases precipitated at the initial stages of crystallisation indicate the possible presence of Frank-Kasper polyhedral structure in the amorphous alloys. Structural analysis reveals that the Laves and the anti-Laves phases have the same polyhedral structural unit, which is similar to the structural characteristics of glass.

  2. Atomic Scale Investigation of Structural Properties and Glass Forming Ability of Ti100- x Al x Metallic Glasses

    Science.gov (United States)

    Tahiri, M.; Hasnaoui, A.; Sbiaai, K.

    2018-06-01

    In this work, we employed molecular dynamics (MD) simulations to study Ti-Al metallic glasses (MGs) using the embedded atom method (EAM) potential to model the atomic interaction with different compositions. The results showed evidence of the metallic glass formation induced by the split occurring in the second peak of the radial distribution function (RDF) curves implying both Ti and Al atoms. The common neighbor analysis (CNA) method confirmed the presence of the icosahedral clusters with a maximum amount observed for an alloy with 75 pct of Al. Analysis of coordination numbers (CNs) indicated that the total CNs are nearly unchanged in these systems. Finally, Voronoi tessellation analyses (VTA) showed a higher value of the number of icosahedral units at Ti25Al75 composition. This specific composition represents a nearby peritectic point localized at a low melting point in the Ti-Al binary phase diagram. The glass forming ability (GFA) becomes important when the fraction of Al increases by forming and connecting "icosahedral-like" clusters (12-coordinated and 13-coordinated ) and by playing a main role in the structure stability of the Ti-Al MGs.

  3. Atomic Scale Investigation of Structural Properties and Glass Forming Ability of Ti100-x Al x Metallic Glasses

    Science.gov (United States)

    Tahiri, M.; Hasnaoui, A.; Sbiaai, K.

    2018-03-01

    In this work, we employed molecular dynamics (MD) simulations to study Ti-Al metallic glasses (MGs) using the embedded atom method (EAM) potential to model the atomic interaction with different compositions. The results showed evidence of the metallic glass formation induced by the split occurring in the second peak of the radial distribution function (RDF) curves implying both Ti and Al atoms. The common neighbor analysis (CNA) method confirmed the presence of the icosahedral clusters with a maximum amount observed for an alloy with 75 pct of Al. Analysis of coordination numbers (CNs) indicated that the total CNs are nearly unchanged in these systems. Finally, Voronoi tessellation analyses (VTA) showed a higher value of the number of icosahedral units at Ti25Al75 composition. This specific composition represents a nearby peritectic point localized at a low melting point in the Ti-Al binary phase diagram. The glass forming ability (GFA) becomes important when the fraction of Al increases by forming and connecting "icosahedral-like" clusters (12-coordinated and 13-coordinated ) and by playing a main role in the structure stability of the Ti-Al MGs.

  4. Colonial Figures: Memories of Street Traders in the Colonial and Early Post-colonial Periods

    Directory of Open Access Journals (Sweden)

    Sheri Lynn Gibbings

    2012-12-01

    Full Text Available This article explores post-colonial memories about street traders among individuals who lived in the former colony of the Dutch East Indies. It argues that these narratives romanticize the relationship between Europeans and indigenous peoples. Street vendors are also used to differentiate between periods within colonial and post-colonial history. The nostalgic representation of interracial contact between Europeans and traders is contrasted with representations of other figures such as the Japanese and the nationalist. A recurring feature of these representations is the ability of Europeans to speak with street traders and imagine what they wanted and needed. The traders are remembered as a social type that transgressed politics and represented the neutrality of the economic sphere as a place for shared communication. The article concludes that the figure of the street vendor contributes to the nostalgic reinvention of the colony but is also used in narratives to differentiate between and mark changes across the colonial and post-colonial periods.

  5. Quantitative response of bone marrow colony-forming units (CFU-C and PFU-C) in weaning beagles exposed to acute whole-body γ irradiation

    International Nuclear Information System (INIS)

    Wilson, F.D.; Stitzel, K.A.; Klein, A.K.; Shifrine, M.; Graham, R.; Jones, M.; Bradley, E.; Rosenblatt, L.S.

    1978-01-01

    Using a methylcellulose-supported bone marrow culture system, the dose-response relationships of suspended granulocyte-monocyte colonies (CFU-C) and adherent fibroblastic colonies (PFU-C) were investigated in 2- to 3-month-old beagles exposed to acute whole-body γ irradiation. Groups of weanling beagles were exposed at a rate of 140 R/hr delivered from a 60 Co γ source achieving total exposures ranging from 0 to 586 R. Twenty-four hours following irradiation, bone marrow was collected, plated into methylcellulose, and after 1 week of incubation both colony types were quantitated. In addition, bone marrow cellularity determinations were made for a variety of bones using an 59 Fe-labeling technique. The results show a D 37 for the linear part of the slope of 70 R for CFU-C. Although within the limits of the experiment a D 37 could not be established for the fibroblastic populations, the results indicate a substantial degree of radioresistance for these elements supporting our previous studies on PFU-C, performed on mice, which suggested a D 37 of approximately 400 R for the progenitors of these fibroblastic elements

  6. Targeted changes of the cell wall proteome influence Candida albicans ability to form single- and multi-strain biofilms.

    Directory of Open Access Journals (Sweden)

    Vitor Cabral

    2014-12-01

    Full Text Available Biofilm formation is an important virulence trait of the pathogenic yeast Candida albicans. We have combined gene overexpression, strain barcoding and microarray profiling to screen a library of 531 C. albicans conditional overexpression strains (∼10% of the genome for genes affecting biofilm development in mixed-population experiments. The overexpression of 16 genes increased strain occupancy within a multi-strain biofilm, whereas overexpression of 4 genes decreased it. The set of 16 genes was significantly enriched for those encoding predicted glycosylphosphatidylinositol (GPI-modified proteins, namely Ihd1/Pga36, Phr2, Pga15, Pga19, Pga22, Pga32, Pga37, Pga42 and Pga59; eight of which have been classified as pathogen-specific. Validation experiments using either individually- or competitively-grown overexpression strains revealed that the contribution of these genes to biofilm formation was variable and stage-specific. Deeper functional analysis of PGA59 and PGA22 at a single-cell resolution using atomic force microscopy showed that overexpression of either gene increased C. albicans ability to adhere to an abiotic substrate. However, unlike PGA59, PGA22 overexpression led to cell cluster formation that resulted in increased sensitivity to shear forces and decreased ability to form a single-strain biofilm. Within the multi-strain environment provided by the PGA22-non overexpressing cells, PGA22-overexpressing cells were protected from shear forces and fitter for biofilm development. Ultrastructural analysis, genome-wide transcript profiling and phenotypic analyses in a heterologous context suggested that PGA22 affects cell adherence through alteration of cell wall structure and/or function. Taken together, our findings reveal that several novel predicted GPI-modified proteins contribute to the cooperative behaviour between biofilm cells and are important participants during C. albicans biofilm formation. Moreover, they illustrate the power

  7. Career Adapt-Abilities Scale--Italian Form: Psychometric Properties and Relationships to Breadth of Interests, Quality of Life, and Perceived Barriers

    Science.gov (United States)

    Soresi, Salvatore; Nota, Laura; Ferrari, Lea

    2012-01-01

    The Career Adapt-Abilities Scale (CAAS)-Italian Form consists of four 6-item scales, which measure concern, control, curiosity, and confidence as psychosocial resources for managing occupational transitions, developmental tasks, and work traumas. The 24-item CAAS-Italian Form is identical to the International Form 2.0. The factor structure was…

  8. Pock forming ability of fowl pox virus isolated from layer chicken and its adaptation in chicken embryo fibroblast cell culture.

    Science.gov (United States)

    Gilhare, Varsha Rani; Hirpurkar, S D; Kumar, Ashish; Naik, Surendra Kumar; Sahu, Tarini

    2015-03-01

    The objective of the present study was to examine pock forming ability of field strain and vaccine strain of fowl pox virus (FPV) in chorioallantoic membrane (CAM) of embryonated chicken eggs and its adaptation in chicken embryo fibroblast (CEF) cell culture. Dry scabs were collected from 25 affected birds in glycerin-saline and preserved at 4°C until processed. Virus was isolated in 10-day-old embryonated chicken eggs by dropped CAM method. The identity of the virus is confirmed by clinical findings of affected birds, pock morphology and histopathology of infected CAM. In addition one field isolate and vaccine strain of FPV was adapted to CEF cell culture. CEF cell culture was prepared from 9-day-old embryonated chicken eggs. Clinical symptoms observed in affected birds include pox lesion on comb, wattle, eyelids and legs, no internal lesions were observed. All field isolates produced similar findings in CAM. Pocks produced by field isolates ranged from 3 mm to 5 mm at the third passage while initial passages edematous thickening and necrosis of CAM was observed. Pocks formed by lyophilized strain were ranges from 0.5 mm to 2.5 mm in diameter scattered all over the membrane at the first passage. Intra-cytoplasmic inclusion bodies are found on histopathology of CAM. At third passage level, the CEF inoculated with FPV showed characteristic cytopathic effect (CPE) included aggregation of cells, syncytia and plaque formation. FPV field isolates and vaccine strain produced distinct pock lesions on CAMs. Infected CAM showed intracytoplasmic inclusion bodies. The CEF inoculated with FPV field isolate as well as a vaccine strain showed characteristic CPE at third passage level.

  9. Two Strains of Lymnaea stagnalis and the Progeny from Their Mating Display Differential Memory-Forming Ability on Associative Learning Tasks.

    Science.gov (United States)

    Sunada, Hiroshi; Totani, Yuki; Nakamura, Ryota; Sakakibara, Manabu; Lukowiak, Ken; Ito, Etsuro

    2017-01-01

    The pond snail Lymnaea stagnalis learns and forms long-term memory (LTM) following both operant conditioning of aerial respiratory behavior and classical conditioning of taste aversive behavior. In the present study, we examined whether there are interstrain differences in the ability to form LTM following these two types of conditioning. A strain of Lymnaea (TC1) collected in Alberta, Canada exhibits superior memory-forming ability following aerial respiratory operant conditioning compared to a laboratory-reared strain of Lymnaea from Netherlands known as the Dutch strain. We asked whether the offspring of the Canadian TC1 and Dutch snails (i.e., filial 1 (F 1 ) cross snails) would have the superior memory ability and found, rather, that their memory ability was average like the Dutch snails. That is, the Canadian TC1 snails have superior ability for LTM formation following aerial respiratory operant conditioning, but the Dutch and the generated F 1 cross have average ability for memory forming. We next examined the Canadian TC1, Dutch and F 1 cross snails for their ability to learn and form memory following conditioned taste aversion (CTA). All three populations showed similar associative CTA responses. However, both LTM formation and the ratio of good-to-poor performers in the memory retention test were much better in the Dutch snails than the Canadian TC1 and F 1 cross snails. The memory abilities of the Canadian TC1 and F 1 cross snails were average. Our present findings, therefore, suggest that snails of different strains have different memory abilities, and the F 1 cross snails do not inherit the memory ability from the smart strain. To our knowledge, there have been a limited number of studies examining differences in memory ability among invertebrate strains, with the exception of studies using mutant flies.

  10. Two Strains of Lymnaea stagnalis and the Progeny from Their Mating Display Differential Memory-Forming Ability on Associative Learning Tasks

    Directory of Open Access Journals (Sweden)

    Hiroshi Sunada

    2017-09-01

    Full Text Available The pond snail Lymnaea stagnalis learns and forms long-term memory (LTM following both operant conditioning of aerial respiratory behavior and classical conditioning of taste aversive behavior. In the present study, we examined whether there are interstrain differences in the ability to form LTM following these two types of conditioning. A strain of Lymnaea (TC1 collected in Alberta, Canada exhibits superior memory-forming ability following aerial respiratory operant conditioning compared to a laboratory-reared strain of Lymnaea from Netherlands known as the Dutch strain. We asked whether the offspring of the Canadian TC1 and Dutch snails (i.e., filial 1 (F1 cross snails would have the superior memory ability and found, rather, that their memory ability was average like the Dutch snails. That is, the Canadian TC1 snails have superior ability for LTM formation following aerial respiratory operant conditioning, but the Dutch and the generated F1 cross have average ability for memory forming. We next examined the Canadian TC1, Dutch and F1 cross snails for their ability to learn and form memory following conditioned taste aversion (CTA. All three populations showed similar associative CTA responses. However, both LTM formation and the ratio of good-to-poor performers in the memory retention test were much better in the Dutch snails than the Canadian TC1 and F1 cross snails. The memory abilities of the Canadian TC1 and F1 cross snails were average. Our present findings, therefore, suggest that snails of different strains have different memory abilities, and the F1 cross snails do not inherit the memory ability from the smart strain. To our knowledge, there have been a limited number of studies examining differences in memory ability among invertebrate strains, with the exception of studies using mutant flies.

  11. Water-limiting conditions alter the structure and biofilm-forming ability of bacterial multispecies communities in the alfalfa rhizosphere.

    Directory of Open Access Journals (Sweden)

    Pablo Bogino

    Full Text Available Biofilms are microbial communities that adhere to biotic or abiotic surfaces and are enclosed in a protective matrix of extracellular compounds. An important advantage of the biofilm lifestyle for soil bacteria (rhizobacteria is protection against water deprivation (desiccation or osmotic effect. The rhizosphere is a crucial microhabitat for ecological, interactive, and agricultural production processes. The composition and functions of bacterial biofilms in soil microniches are poorly understood. We studied multibacterial communities established as biofilm-like structures in the rhizosphere of Medicago sativa (alfalfa exposed to 3 experimental conditions of water limitation. The whole biofilm-forming ability (WBFA for rhizospheric communities exposed to desiccation was higher than that of communities exposed to saline or nonstressful conditions. A culture-dependent ribotyping analysis indicated that communities exposed to desiccation or saline conditions were more diverse than those under the nonstressful condition. 16S rRNA gene sequencing of selected strains showed that the rhizospheric communities consisted primarily of members of the Actinobacteria and α- and γ-Proteobacteria, regardless of the water-limiting condition. Our findings contribute to improved understanding of the effects of environmental stress factors on plant-bacteria interaction processes and have potential application to agricultural management practices.

  12. Effect of Si addition on the glass-forming ability of a NiTiZrAlCu alloy

    International Nuclear Information System (INIS)

    Liang, W.Z.; Shen, J.; Sun, J.F.

    2006-01-01

    The effect of Si addition on the glass-forming ability (GFA) of a NiTiZrAlCu alloy was investigated by using differential scanning calorimetry (DSC), differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The maximum diameter of glassy rods increased from 0.5 mm for the Ni 42 Ti 20 Zr 25 Al 8 Cu 5 alloy (the base alloy) to 2.5 mm for the Ni 42 Ti 20 Zr 21.5 Al 8 Cu 5 Si 3.5 alloy and to 3 mm for the Ni 42 Ti 19 Zr 22.5 Al 8 Cu 5 Si 3.5 alloy, when prepared by using the copper mould casting. The GFA of the alloys can be assessed by the reduced glass transition temperature T rg (=T g /T l ) and a newly proposed parameter, δ(=T x /T l - T g ). An addition of a proper amount of Si and a minor substitution of Ti with Zr can enhance the GFA of the base alloy by suppressing the formation of primary Ni(TiZr) and (TiZr)(CuAl) 2 phases and inducing the composition close to eutectic

  13. Biofilm forming ability of Sphingomonas paucimobilis isolated from community drinking water systems on plumbing materials used in water distribution.

    Science.gov (United States)

    Gulati, Parul; Ghosh, Moushumi

    2017-10-01

    Sphingomonas paucimobilis, an oligotroph, is well recognized for its potential for biofilm formation. The present study explored the biofilm forming ability of a strain isolated from municipal drinking water on plumbing materials. The intensity of biofilm formation of this strain on different plumbing materials was examined by using 1 × 1 cm 2 pieces of six different pipe materials, i.e. polyvinyl chloride (PVC), polypropylene (PP), polyethylene (PE), aluminium (Al), copper (Cu) and rubber (R) and observing by staining with the chemical chromophore, Calcofluor. To understand whether biofilm formation occurs under flow through conditions, a laboratory-scale simulated distribution system, comprised of the above materials was fabricated. Biofilm samples were collected from the designed system at different biofilm ages (10, 40 and 90 hours old) and enumerated. The results indicated that the biofilm formation occurred on all plumbing materials with Cu and R as exceptions. The intensity of biofilm formation was found to be maximum on PVC followed by PP and PE. We also demonstrated the chemical chromophore (Calcofluor) successfully for rapid and easy visual detection of biofilms, validated by scanning electron microscope (SEM) analysis of the plumbing materials. Chlorination has little effect in preventing biofilm development.

  14. Glass forming ability of the Fe-Zr-Cu system studied by thermodynamic calculation and ion beam mixing

    International Nuclear Information System (INIS)

    Wang, T.L.; Liu, B.X.

    2009-01-01

    The glass forming ability/range (GFA/GFR) of the Fe-Zr-Cu system was studied by thermodynamic calculation based on Miedema's model and Alonso's method. It is found that when the atomic concentration of Zr is between 34% and 56%, no matter what the atomic concentrations of Fe and Cu are, amorphous phase could be obtained, thus the atomic mismatch playing a dominating role in influencing the GFA. While the atomic concentration of Zr is out of the above range, the GFA is highly influenced by the immiscibility between Fe and Cu. Experimentally, ion beam mixing was carried out to synthesize amorphous alloys in the Fe-Zr-Cu system. It turned out that in the samples with overall compositions of Fe 26 Zr 36 Cu 38 , Fe 52 Zr 27 Cu 21 and Fe 21 Zr 60 Cu 19 , which are located in or at the edge of the calculated GFR, amorphous phases were indeed obtained, whereas no amorphous phase was obtained if the overall compositions were located outside of the predicted region favoring for amorphous alloy formation, showing a good agreement between the experimental results and the thermodynamic calculation.

  15. Speech and language abilities of children with the familial form of 22q11.2 deletion syndrome

    Directory of Open Access Journals (Sweden)

    Rakonjac Marijana

    2016-01-01

    Full Text Available The 22q11.2 Deletion Syndrome (22q11.2DS, which encompasses Shprintzen syndrome, DiGeorge and velocardiofacial syndrome, is the most common microdeletion syndrome in humans with an estimated incidence of approximately 1/4000 per live births. After Down syndrome, it is the second most common genetic syndrome associated with congenital heart malformations. The mode of inheritance of the 22q11.2DS is autosomal dominant. In approximately 72 - 94% of the cases the deletion has occurred de novo, while in 6 to 28% of patients deletion was inherited from a parent. As a part of a multidisciplinary study we examined the speech and language abilities of members of two families with inherited form of 22q11.2DS. The presence of 22q11.2 microdeletion was revealed by fluorescence in situ hybridization (FISH and/or multiplex ligation-dependent probe amplification (MLPA. In one family we detected 1.5 Mb 22q11.2 microdeletion, while in the other family we found 3Mb microdeletion. Patients from both families showed delays in cognitive, socio-emotional, speech and language development. Furthermore, we found considerable variability in the phenotypic characteristics of 22q11.2DS and the degree of speech-language pathology not only between different families with 22q11.2 deletion, but also among members of the same family. In addition, we detected no correlation between the phenotype and the size of 22q11.2 microdeletion.

  16. Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability

    Directory of Open Access Journals (Sweden)

    Suzan Bsat

    2015-04-01

    Full Text Available Advanced additive manufacturing techniques such as electron beam melting (EBM, can produce highly porous structures that resemble the mechanical properties and structure of native bone. However, for orthopaedic applications, such as joint prostheses or bone substitution, the surface must also be bio-functionalized to promote bone growth. In the current work, EBM porous Ti6Al4V alloy was exposed to an alkali acid heat (AlAcH treatment to bio-functionalize the surface of the porous structure. Various molar concentrations (3, 5, 10M and immersion times (6, 24 h of the alkali treatment were used to determine optimal parameters. The apatite forming ability of the samples was evaluated using simulated body fluid (SBF immersion testing. The micro-topography and surface chemistry of AlAcH treated samples were evaluated before and after SBF testing using scanning electron microscopy and energy dispersive X-ray spectroscopy. The AlAcH treatment successfully modified the topographical and chemical characteristics of EBM porous titanium surface creating nano-topographical features ranging from 200–300 nm in size with a titania layer ideal for apatite formation. After 1 and 3 week immersion in SBF, there was no Ca or P present on the surface of as manufactured porous titanium while both elements were present on all AlAcH treated samples except those exposed to 3M, 6 h alkali treatment. An increase in molar concentration and/or immersion time of alkali treatment resulted in an increase in the number of nano-topographical features per unit area as well as the amount of titania on the surface.

  17. Selected mucolytic, anti-inflammatory and cardiovascular drugs change the ability of neutrophils to form extracellular traps (NETs).

    Science.gov (United States)

    Zawrotniak, Marcin; Kozik, Andrzej; Rapala-Kozik, Maria

    2015-01-01

    Neutrophils form the first line of host defense against infections that combat pathogens using two major mechanisms, the phagocytosis or the release of neutrophil extracellular traps (NETs). The netosis (NET formation) exerts additional, unfavorable effects on the fitness of host cells and is also involved at the sites of lung infection, increasing the mucus viscosity and in the circulatory system where it can influence the intravascular clot formation. Although molecular mechanisms underlying the netosis are still incompletely understood, a role of NADPH oxidase that activates the production of reactive oxygen species (ROS) during the initiation of NETs has been well documented. Since several commonly used drugs can affects the netosis, our current study was aimed to determine the effects of selected mucolytic, anti-inflammatory and cardiovascular drugs on NET formation, with a special emphasis on ROS production and NADPH oxidase activity. The treatment of neutrophils with N-acetylcysteine, ketoprofen and ethamsylate reduced the production of ROS by these cells in a dose-dependent manner. NET formation was also modulated by selected drugs. N-acetylcysteine inhibited the netosis but in the presence of H2O2 this neutrophil ability was restored, indicating that N-acetylcysteine may influence the NET formation by modulating ROS productivity. The administration of ethamsylate led to a significant reduction in NET formation and this effect was not restored by H2O2 or S. aureus, suggesting the unexpected additional side effects of this drug. Ketoprofen seemed to promote ROS-independent NET release, simultaneously inhibiting ROS production. The results, obtained in this study strongly suggest that the therapeutic strategies applied in many neutrophil-mediated diseases should take into account the NET-associated effects.

  18. Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability.

    Science.gov (United States)

    Bsat, Suzan; Yavari, Saber Amin; Munsch, Maximilian; Valstar, Edward R; Zadpoor, Amir A

    2015-04-08

    Advanced additive manufacturing techniques such as electron beam melting (EBM), can produce highly porous structures that resemble the mechanical properties and structure of native bone. However, for orthopaedic applications, such as joint prostheses or bone substitution, the surface must also be bio-functionalized to promote bone growth. In the current work, EBM porous Ti6Al4V alloy was exposed to an alkali acid heat (AlAcH) treatment to bio-functionalize the surface of the porous structure. Various molar concentrations (3, 5, 10M) and immersion times (6, 24 h) of the alkali treatment were used to determine optimal parameters. The apatite forming ability of the samples was evaluated using simulated body fluid (SBF) immersion testing. The micro-topography and surface chemistry of AlAcH treated samples were evaluated before and after SBF testing using scanning electron microscopy and energy dispersive X-ray spectroscopy. The AlAcH treatment successfully modified the topographical and chemical characteristics of EBM porous titanium surface creating nano-topographical features ranging from 200-300 nm in size with a titania layer ideal for apatite formation. After 1 and 3 week immersion in SBF, there was no Ca or P present on the surface of as manufactured porous titanium while both elements were present on all AlAcH treated samples except those exposed to 3M, 6 h alkali treatment. An increase in molar concentration and/or immersion time of alkali treatment resulted in an increase in the number of nano-topographical features per unit area as well as the amount of titania on the surface.

  19. Effect of Si addition on glass-forming ability and mechanical properties of Cu-Zr-Al bulk metallic glass

    International Nuclear Information System (INIS)

    Malekan, M.; Shabestari, S.G.; Zhang, W.; Seyedein, S.H.; Gholamipour, R.; Makino, A.; Inoue, A.

    2010-01-01

    Research highlights: The Cu 50 Zr 43 Al 7 alloy has a surprising GFA, and the glassy rods with diameter of 10 mm have been produced in this research. It has not been reported that the Cu-based glassy rods (Cu ≥ 50 at.%) to be produced with the critical diameter greater than 10 mm. The novelty of this research is that the glass formation has been improved and the critical diameter increased to 12 mm for the alloy having x = 1 with the addition of Si. Different criteria are used to evaluate the influence of Si content on the GFA, and the possible mechanisms involved in the achievement of this GFA are also discussed. - Abstract: The effect of Si addition on the glass-forming ability (GFA) and mechanical properties of (Cu 50 Zr 43 Al 7 ) 100-x Si x (x = 0, 0.5, 1, 1.5 and 2 at.%) alloys were investigated. The GFA of Cu 50 Zr 43 Al 7 alloy is improved by addition of a small amount of Si, and the critical diameter for glass formation increases from 10 mm for the alloy with x = 0-12 mm for the alloy with x = 1 when prepared using copper mold casting. Different criteria are used to evaluate the influence of Si content on the GFA, and the possible mechanisms involved in the achievement of this GFA are also discussed. In the uniaxial compression, the bulk glassy alloys exhibit a limited plastic strain of less than 1%, but the compressive fracture strength and Young's modulus were obtained in high values of 1969-2129 MPa and 101-144 GPa, respectively. Fracture surface and shear bands of samples were studied by using scanning electron microscopy (SEM).

  20. Effects of Cu substitution for Fe on the glass-forming ability and soft magnetic properties for Fe-based bulk metallic glasses

    International Nuclear Information System (INIS)

    Dou, Lintao; Liu, Haishun; Hou, Long; Xue, Lin; Yang, Weiming; Zhao, Yucheng; Chang, Chuntao

    2014-01-01

    The effects of Cu substitution for Fe on the glass-forming ability (GFA) and soft magnetic properties for Fe 72−x Cu x B 20 Si 4 Nb 4 (x=0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) bulk metallic glasses (BMGs) are investigated. It is found that the investigated BMGs exhibit large GFA as well as excellent soft magnetic properties, and proper substitution of Fe by Cu improves the saturation magnetization, coercive force, and effective permeability without obvious deterioration of the GFA. - Highlights: • Fully glassy rods of Fe 72−x Cu x B 20 Si 4 Nb 4 BMGs were produced above 1 mm in diameter. • Investigated BMGs exhibit large glass-forming ability and excellent soft magnetic properties. • Proper Cu substitution improves magnetic properties without obvious deterioration of glass-forming ability

  1. On colonial grounds

    NARCIS (Netherlands)

    Dommelen, Peter Alexander René van

    1998-01-01

    As a study of the colonial situations of first millennium BC Sardinia, this book is as much an investigation into colonialism as a sociological category, as it explores the specific historical conditions of a particular region. Taking a fresh look at colonialism in Mediterranean archaeology from a

  2. Forty years of the Hrubý glass-forming coefficient via DTA when comparing other criteria in relation to the glass stability and vitrification ability

    Czech Academy of Sciences Publication Activity Database

    Kozmidis-Petrovic, A.; Šesták, Jaroslav

    2012-01-01

    Roč. 110, č. 2 (2012), 997-1004 ISSN 1388-6150 Institutional research plan: CEZ:AV0Z10100521 Keywords : glass transition * Hrubý criterion * glass -forming ability * DTA/DSC Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.982, year: 2012

  3. Study on glass-forming ability and hydrogen storage properties of amorphous Mg60Ni30La10−xCox (x = 0, 4) alloys

    International Nuclear Information System (INIS)

    Lv, Peng; Wang, Zhong-min; Zhang, Huai-gang; Balogun, Muhammad-Sadeeq; Ji, Zi-jun; Deng, Jian-qiu; Zhou, Huai-ying

    2013-01-01

    Mg 60 Ni 30 La 10−x Co x (x = 0, 4) amorphous alloys were prepared by rapid solidification, using a melt-spinning technique. X-ray diffraction and differential scanning calorimetry analysis were employed to measure their microstructure, thermal stability and glass-forming ability, and hydrogen storage properties were studied by means of PCTPro2000. Based on differential scanning calorimetry results, their glass-forming ability and thermal stability were investigated by Kissinger method, Lasocka curves and atomic cluster model, respectively. The results indicate that glass-forming ability, thermal properties and hydrogen storage properties in the Mg-rich corner of Mg–Ni–La–Co system alloys were enhanced by Co substitution for La. It can be found that the smaller activation energy (ΔΕ) and frequency factor (υ 0 ), the bigger value of B (glass transition point in Lasocka curves), and higher glass-forming ability of Mg–Ni–La–Co alloys would be followed. In addition, atomic structure parameter (λ), deduced from atomic cluster model is valuable in the design of Mg–Ni–La–Co system alloys with good glass-forming ability. With an increase of Co content from 0 to 4, the hydrogen desorption capacity within 4000 s rises from 2.25 to 2.85 wt.% at 573 K. - Highlights: • Amorphous Mg 60 Ni 30 La 10−x Co x (x = 0 and 4) alloys were produced by melt spinning. • The GFA and hydrogen storage properties were enhanced by Co substitution for La. • With an increase of Co content, the hydrogen desorption capacity rises at 573 K

  4. Training Lymnaea in the presence of a predator scent results in a long-lasting ability to form enhanced long-term memory.

    Science.gov (United States)

    Forest, Jeremy; Sunada, Hiroshi; Dodd, Shawn; Lukowiak, Ken

    2016-06-01

    Lymnaea exposed to crayfish effluent (CE) gain an enhanced ability to form long-term memory (LTM). We test the hypothesis that a single CE exposure and operant conditioning training leads to long lasting changes in the capability of snails to form LTM when tested in pond water four weeks later. We trained both juvenile and adult snails with a single 0.5 h training session in CE and show that LTM was present 24 h later. Snails trained in a similar manner in just pond water show no LTM. We then asked if such training in CE conferred enhanced memory forming capabilities on these snails four weeks later. That is, would LTM be formed in these snails four weeks later following a single 0.5 h training session in pond water? We found that both adult and juvenile snails previously trained in CE one month previously had enhanced LTM formation abilities. The injection of a DNA methylation blocker, 5-AZA, prior to training in adult snails blocked enhanced LTM formation four weeks later. Finally, this enhanced LTM forming ability was not passed on to the next generation of snails.

  5. Early Developmental Program Shapes Colony Morphology in Bacteria

    Directory of Open Access Journals (Sweden)

    Gideon Mamou

    2016-03-01

    Full Text Available When grown on a solid surface, bacteria form highly organized colonies, yet little is known about the earliest stages of colony establishment. Following Bacillus subtilis colony development from a single progenitor cell, a sequence of highly ordered spatiotemporal events was revealed. Colony was initiated by the formation of leading-cell chains, deriving from the colony center and extending in multiple directions, typically in a “Y-shaped” structure. By eradicating particular cells during these early stages, we could influence the shape of the resulting colony and demonstrate that Y-arm extension defines colony size. A mutant in ymdB encoding a phosphodiesterase displayed unordered developmental patterns, indicating a role in guiding these initial events. Finally, we provide evidence that intercellular nanotubes contribute to proper colony formation. In summary, we reveal a “construction plan” for building a colony and provide the initial molecular basis for this process.

  6. Strong composition-dependence on glass-forming ability in Ni-(Ti,Zr)-Si pseudo-ternary alloys

    International Nuclear Information System (INIS)

    Yang, H.; Wang, J.Q.; Li, Y.

    2006-01-01

    The glass formation in Ni-(Ti,Zr)-Si pseudo-ternary alloys was studied. For suction casting, by carefully adjusting the alloy composition and studying the microstructure changes, the best glass-forming alloy with a 2 mm diameter is pinpointed in a narrow composition region of 57.5-58.5 at.% Ni, 36.5-38.5 at.% (Ti + Zr) and 5-5.5 at.% Si. The main competing crystalline phases, identified by XRD and SEM, were Ni 10 (Zr,Ti) 7 , Ni(Ti,Zr) and an unidentified Si-containing phase. Our results indicate a clear need for monitoring the microstructure change in the cross section of the ingots to locate the best glass-forming alloys

  7. Genetic control of the radiosensitivity of lymphoid cells for antibody-forming ability in CXS series of recombinant inbred mouse strains

    International Nuclear Information System (INIS)

    Okumoto, M.; Mori, N.; Nishikawa, R.; Imai, S.; Hilgers, J.; Takamori, Y.; Yagasaki, O.

    1992-01-01

    Incidence of radiation-induced lymphomas differs remarkably among various mouse strains. BALB/cHeA (C) mice are highly susceptible to radiation induction of lymphomas, while STS/A (S) mice are resistant. Thus, the induction of the disease is controlled by some genetic factors. To examine an involvement of radiosensitivity of lymphoid cells in lymphomagenesis, we have compared genetic control of the radiosensitivity for antibody-forming ability with that of lymphoma development in BALB/cHeA, STS/A, (CXS)F 1 hybrids and CXS series of recombinant inbred strains. Decrease of number of splenic plaque-forming cell (PFC) in Jerne's method by 3 Gy of X-irradiation for BALB/cHeA mice was larger than that for STS/A mice by more than one order of magnitude. (CXS)F 1 hybrid mice showed small number of decrease of PFC similar to STS/A mice suggesting that phenotype of radioresistance was dominant over sensitivity. The best concordance between genetic markers and radiosensitivities of antibody-forming ability in recombinant inbred strains was observed in a region containing Igh locus on chromosome 12. The results show that one locus controlling the radioresistance of lymphoid cells for antibody-forming ability might exist in the region containing Igh locus, and that this region clearly differ from a region with Ifa locus on chromosome 4 which regulate the susceptibility to radiation-induced lymphomagenesis. (author)

  8. Menaquinone and iron are essential for complex colony development in Bacillus subtilis.

    Directory of Open Access Journals (Sweden)

    Gidi Pelchovich

    Full Text Available Cells of undomesticated species of Bacillus subtilis frequently form complex colonies during spreading on agar surfaces. Given that menaquinone is involved in another form of coordinated behavior, namely, sporulation, we looked for a possible role for menaquinone in complex colony development (CCD in the B. subtilis strain NCIB 3610. Here we show that inhibition of menaquinone biosynthesis in B. subtilis indeed abolished its ability to develop complex colonies. Additionally some mutations of B. subtilis which confer defective CCD could be suppressed by menaquinone derivatives. Several such mutants mapped to the dhb operon encoding the genes responsible for the biosynthesis of the iron siderophore, bacillibactin. Our results demonstrate that both menaquinone and iron are essential for CCD in B. subtilis.

  9. Readiness of senior higher school students for self-determination in ecology field as an ability to form subjective attitude

    Directory of Open Access Journals (Sweden)

    Titov Evgeny V.

    2016-01-01

    Full Text Available The current state of environment demands from senior pupils to occupy a correct position in problem ecological situations. An effective means of forming senior pupils’ own position is activity in a field of ecology. Through a variety of activities in the field of ecology (learning, playing, research, environmental protection, and others. senior pupils are involved in situations requiring self-determination. Self-determined senior pupils overcome a conflict, a contradiction between an individual’’s position and a social role caused by a situation arising in activity.

  10. Mechanism of stimulation of antibody-forming ability of bone marrow cells of mice immunized with staphylococci

    International Nuclear Information System (INIS)

    Lyashchenko, K.P.; Golovanova, T.A.; Bobrovnik, S.A.

    1987-01-01

    The purpose of this paper is to study the formation of the ability of the bone marrow cells of mice immunized with staphylococci to create antibodies to this antigen. The research includes a study of the effect of the irradiation in vitro of the bone marrow cells on their stimulating activity and the role played by the thymus and spleen in the formation of this activity. Experiments were carried out on CBA and BALB/c mice as well as on mice with congenital absence of the thymus. The bone marrow cell donors were immunized intravenously with staphylococcal corpuscular antigen. Receptor mice were irradiated with cobalt 60 gamma radiation and injected intravenously with bone marrow cell extract from the immunized donors and were immunized with the antigen. Spleen cells were labelled with chromium 51 and injected intravenously into intact syngeneic recipients together with as well as without the antigen. Three days later the level of radioactivity in the spleen and femora of the animals was determined by scintillation counting. Total radioactivity of the bone marrow was calculated. Irradiation of the bone marrow cells of immunized animals was shown to abolish their stimulating effect on the humoral immune response of intact syngeneic recipients to the staphylococcal corpuscular antigen. Consequently, the immunostimulating effect of bone marrow cells is realized through the proliferating and radiosensitive lymphoid cells rather than through the macrophages

  11. An American termite in Paris: temporal colony dynamics.

    Science.gov (United States)

    Baudouin, Guillaume; Dedeine, Franck; Bech, Nicolas; Bankhead-Dronnet, Stéphanie; Dupont, Simon; Bagnères, Anne-Geneviève

    2017-12-01

    Termites of the genus Reticulitermes are widespread invaders, particularly in urban habitats. Their cryptic and subterranean lifestyle makes them difficult to detect, and we know little about their colony dynamics over time. In this study we examined the persistence of Reticulitermes flavipes (Kollar) colonies in the city of Paris over a period of 15 years. The aim was (1) to define the boundaries of colonies sampled within the same four areas over two sampling periods, (2) to determine whether the colonies identified during the first sampling period persisted to the second sampling period, and (3) to compare the results obtained when colonies were delineated using a standard population genetic approach versus a Bayesian clustering method that combined both spatial and genetic information. Herein, colony delineations were inferred from genetic differences at nine microsatellite loci and one mitochondrial locus. Four of the 18 identified colonies did not show significant differences in their genotype distributions between the two sampling periods. While allelic richness was low, making it hard to reliably distinguish colony family type, most colonies appeared to retain the same breeding structure over time. These large and expansive colonies showed an important ability to fuse (39% were mixed-family colonies), contained hundreds of reproductives and displayed evidence of isolation-by-distance, suggesting budding dispersal. These traits, which favor colony persistence over time, present a challenge for pest control efforts, which apply treatment locally. The other colonies showed significant differences, but we cannot exclude the possibility that their genotype distributions simply changed over time.

  12. In vitro studies of the sensitivity of canine bone-marrow erythroid burst-forming units (BFU-E) and fibroblast colony-forming units (CFU-F) to X-irradiation

    International Nuclear Information System (INIS)

    Kreja, Ludwika; Baltschukat, Klaus; Nothdurft, Wilhelm

    1989-01-01

    The radiosensitivity of the early erythroid progenitor cells (BFU-E) and the progenitor cells of the stroma (CFU-F) in canine bone marrow was studied under steady-state conditions by in vitro irradiation with 280 kV X-rays. The dose-effect relationship for colony formation was determined for BFU-E obtained from the iliac crest marrow, and for CFU-F in bone marrow collected from the iliac crest and the humerus of adult beagles. The BFU-E were adequately stimulated with serum from lethally irradiated dogs to obtain a source of BPA (burst-promoting activity). The BFU-E proved to be extremely radiosensitive, (the survival curve was exponential (D o 15.3 ± 1.8 cGY)). Buffy-coat leukocytes separated from bone marrow leukocytes obtained by aspiration were an optimum source of CFU-F. A curve was fitted to data obtained for CFU-F obtained from iliac crest or humerus, resulting in D o = 241 ± 38 cGY and an extrapolation number n = 1.38 ± 0.62 or D o = 261 ± 40 cGY and n = 1.04 ± 0.42, respectively. (author)

  13. The fundamental structural factor in determining the glass-forming ability and mechanical behavior in the Cu-Zr metallic glasses

    International Nuclear Information System (INIS)

    Sha, Z.D.; Feng, Y.P.; Li, Y.

    2011-01-01

    Research highlights: → A weak but significant hump in trend of the coordinate number and density was observed, respectively. → Our findings indicate our simulation is more accurate to describe the atomic structure of Cu-Zr MGs. The composition-structure-properties correlation was established. → And the effective structural unit for this correlation is the Cu-centered full icosahedra. - Abstract: Using the large-scale atomic/molecular massively parallel simulator, the quantitative composition-structure-properties (including glass-forming ability (GFA) and mechanical behavior) correlations in the Cu-Zr metallic glasses were established. The atomic-level origin of these correlations was tracked down. It was found that the Cu-centered full icosahedron is the microscopic factor that fundamentally influences both GFA and mechanical behavior. Our findings have implications for understanding the nature, forming ability and properties of metallic glasses, and for searching novel metallic glasses with unique functional properties.

  14. Dependence of glass-forming ability on starting compositions in Y2O3–Al2O3–SiO2 system

    OpenAIRE

    Yixiang Chen; Zengchao Yang; Bin He; Guanghua Liu; Jiangtao Li; Liang Wu

    2011-01-01

    The dependence of glass-forming ability on starting compositions in Y2O3–Al2O3–SiO2 (YAS) system has been investigated by melting experiment. Transparent YAS glasses have been prepared under the condition of furnace cooling instead of quenching. It is found that, in the YAS ternary phase diagram, the compositions on the Y3Al5O12–SiO2 line and with 52-68 mol% SiO2 have a higher glass-forming ability to produce pure glass. For the compositions with too much or less SiO2 or with Y/Al = 5/3, 1/1,...

  15. Effect of solute atoms on glass-forming ability for Fe–Y–B alloy: An ab initio molecular dynamics study

    International Nuclear Information System (INIS)

    Han, J.J.; Wang, W.Y.; Liu, X.J.; Wang, C.P.; Hui, X.D.; Liu, Z.K.

    2014-01-01

    The glass-forming abilities of Fe 78 B 22 , Fe 70 Y 6 B 24 , Fe 72 Y 6 B 22 and Fe 72.5 Y 3.5 B 24 alloys were characterized comprehensively using ab initio molecular dynamics simulations. The calculated results were correlated with the properties and atomic structures. It was found that the Fe 72 Y 6 B 22 alloy consists of both the most stable and the least deformed body centered cubic atomic packing structures in the supercooled liquid and glassy states. It was observed that the local compositions in the Fe 72 Y 6 B 22 alloy significantly deviate from the compositions of stable crystalline phases, indicating that the Fe 72 Y 6 B 22 alloy has the best glass-forming ability among the alloys studied. However, Fe 72 Y 6 B 22 alloy has two flaws in terms of glass-forming ability, i.e. relatively large atomic diffusivity and insufficiently close atomic packing. The best performance in these two aspects is observed in the Fe 72.5 Y 3.5 B 24 alloy. Thus, the theoretical study predicts that the best glass former for the Fe–Y–B system is within the compositional range of 22–24 at.% B and 3.5–6 at.% Y

  16. The Relationship between Intrinsic Couplings of the Visual Word Form Area with Spoken Language Network and Reading Ability in Children and Adults

    Directory of Open Access Journals (Sweden)

    Yu Li

    2017-06-01

    Full Text Available Reading plays a key role in education and communication in modern society. Learning to read establishes the connections between the visual word form area (VWFA and language areas responsible for speech processing. Using resting-state functional connectivity (RSFC and Granger Causality Analysis (GCA methods, the current developmental study aimed to identify the difference in the relationship between the connections of VWFA-language areas and reading performance in both adults and children. The results showed that: (1 the spontaneous connectivity between VWFA and the spoken language areas, i.e., the left inferior frontal gyrus/supramarginal gyrus (LIFG/LSMG, was stronger in adults compared with children; (2 the spontaneous functional patterns of connectivity between VWFA and language network were negatively correlated with reading ability in adults but not in children; (3 the causal influence from LIFG to VWFA was negatively correlated with reading ability only in adults but not in children; (4 the RSFCs between left posterior middle frontal gyrus (LpMFG and VWFA/LIFG were positively correlated with reading ability in both adults and children; and (5 the causal influence from LIFG to LSMG was positively correlated with reading ability in both groups. These findings provide insights into the relationship between VWFA and the language network for reading, and the role of the unique features of Chinese in the neural circuits of reading.

  17. Effect of P addition on glass forming ability and soft magnetic properties of melt-spun FeSiBCuC alloy ribbons

    International Nuclear Information System (INIS)

    Xu, J.; Yang, Y.Z.; Li, W.; Chen, X.C.; Xie, Z.W.

    2016-01-01

    The dependency of phosphorous content on the glass forming ability, thermal stability and soft magnetic properties of Fe 83.4 Si 2 B 14−x P x Cu 0.5 C 0.1 (x=0,1,2,3,4) alloys was investigated. The experimental results showed that the substitution of B by P increased the glass forming ability in this alloy system. The Fe 83.4 Si 2 B 10 P 4 Cu 0.5 C 0.1 alloy shows a fully amorphous character. Thermal stability of melt-spun ribbons increases and temperature interval between the first and second crystallization peaks enlarges with the increase of P content. And the saturation magnetic flux density (Bs) shows a slight increase with the increase of P content. The Fe 83.4 Si 2 B 11 P 3 Cu 0.5 C 0.1 nanocrystalline alloy exhibits a high Bs about 200.6 emu/g. The Bs of fully amorphous alloy Fe 83.4 Si 2 B 10 P 4 Cu 0.5 C 0.1 drops dramatically to 172.1 emu/g, which is lower than that of other nanocrystallines. Low material cost and excellent soft magnetic properties make the FeSiBPCuC alloys promise soft magnetic materials for industrial applications. - Highlights: • Partial substituting B by P helps to improve the glass forming ability of the alloy. • The addition of P content reduces the thermal stability and improves heat treatment temperature region for these alloys. • The Fe 83.4 Si 2 B 11 P 3 Cu 0.5 C 0.1 nanocrystalline alloy exhibits a high saturation magnetic density of 200.6 emu/g.

  18. Enhanced apatite-forming ability and antibacterial activity of porous anodic alumina embedded with CaO-SiO2-Ag2O bioactive materials.

    Science.gov (United States)

    Ni, Siyu; Li, Xiaohong; Yang, Pengan; Ni, Shirong; Hong, Feng; Webster, Thomas J

    2016-01-01

    In this study, to provide porous anodic alumina (PAA) with bioactivity and anti-bacterial properties, sol-gel derived bioactive CaO-SiO2-Ag2O materials were loaded onto and into PAA nano-pores (termed CaO-SiO2-Ag2O/PAA) by a sol-dipping method and subsequent calcination of the gel-glasses. The in vitro apatite-forming ability of the CaO-SiO2-Ag2O/PAA specimens was evaluated by soaking them in simulated body fluid (SBF). The surface microstructure and chemical property before and after soaking in SBF were characterized. Release of ions into the SBF was also measured. In addition, the antibacterial properties of the samples were tested against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The results showed that CaO-SiO2-Ag2O bioactive materials were successfully decorated onto and into PAA nano-pores. In vitro SBF experiments revealed that the CaO-SiO2-Ag2O/PAA specimens dramatically enhanced the apatite-forming ability of PAA in SBF and Ca, Si and Ag ions were released from the samples in a sustained and slow manner. Importantly, E. coli and S. aureus were both killed on the CaO-SiO2-Ag2O/PAA (by 100%) samples compared to PAA controls after 3 days of culture. In summary, this study demonstrated that the CaO-SiO2-Ag2O/PAA samples possess good apatite-forming ability and high antibacterial activity causing it to be a promising bioactive coating candidate for implant materials for orthopedic applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Development and psychometric characteristics of the SCI-QOL Ability to Participate and Satisfaction with Social Roles and Activities item banks and short forms.

    Science.gov (United States)

    Heinemann, Allen W; Kisala, Pamela A; Hahn, Elizabeth A; Tulsky, David S

    2015-05-01

    To develop a spinal cord injury (SCI)-focused version of PROMIS and Neuro-QOL social domain item banks; evaluate the psychometric properties of items developed for adults with SCI; and report information to facilitate clinical and research use. We used a mixed-methods design to develop and evaluate Ability to Participate in Social Roles and Activities and Satisfaction with Social Roles and Activities items. Focus groups helped define the constructs; cognitive interviews helped revise items; and confirmatory factor analysis and item response theory methods helped calibrate item banks and evaluate differential item functioning related to demographic and injury characteristics. Five SCI Model System sites and one Veterans Administration medical center. The calibration sample consisted of 641 individuals; a reliability sample consisted of 245 individuals residing in the community. A subset of 27 Ability to Participate and 35 Satisfaction items demonstrated good measurement properties and negligible differential item functioning related to demographic and injury characteristics. The SCI-specific measures correlate strongly with the PROMIS and Neuro-QOL versions. Ten item short forms correlate >0.96 with the full banks. Variable-length CATs with a minimum of 4 items, variable-length CATs with a minimum of 8 items, fixed-length CATs of 10 items, and the 10-item short forms demonstrate construct coverage and measurement error that is comparable to the full item bank. The Ability to Participate and Satisfaction with Social Roles and Activities CATs and short forms demonstrate excellent psychometric properties and are suitable for clinical and research applications.

  20. Comparative evaluation of rotary ProTaper, Profile, and conventional stepback technique on reduction in Enterococcus faecalis colony-forming units and vertical root fracture resistance of root canals.

    Science.gov (United States)

    Singla, Mamta; Aggarwal, Vivek; Logani, Ajay; Shah, Naseem

    2010-03-01

    The purpose of this in vitro study was to evaluate the effect of various root canal instrumentation techniques with different instrument tapers on cleaning efficacy and resultant vertical root fracture (VRF) strength of the roots. Fifty human mandibular first premolar roots were enlarged to ISO size 20, inoculated with Enterococcus faecalis [ATCC2912] for 72 hours and divided into 5 groups: group I: prepared with .02 taper hand instruments ISO size 40; group II: Profile .04 taper size 40; group III: Profile .06 taper size 40; group IV: ProTaper size F4; and group V (control group) further divided into: Va: with bacterial inoculation and no mechanical instrumentation; and Group Vb: neither bacterial inoculation nor mechanical instrumentation. Cleaning efficacy was evaluated in terms of reduction of colony forming units (CFUs). The VRF strength was evaluated using D11 spreader as wedge in an Instron testing machine. Root canals instrumented with ProTaper and 6% Profile instruments showed maximum reduction in CFUs, with statistically insignificant difference between them. The VRF resistance decreased in all instrumented groups. The difference of VRF between 2% and 4% taper Profile groups was statistically insignificant (P = .195). One-way analysis of variance showed that canals instrumented with ProTaper F4 showed maximum reduction in VRF resistance compared with control uninstrumented group. Profile 6% taper instruments offer the advantage of maximum debridement without significant reduction in root fracture resistance. Copyright 2010 Mosby, Inc. All rights reserved.

  1. Improvement of corrosion resistance in NaOH solution and glass forming ability of as-cast Mg-based bulk metallic glasses by microalloying

    Directory of Open Access Journals (Sweden)

    Peng Hao

    2011-02-01

    Full Text Available The influences of the addition of Ag on the glass forming ability (GFA and corrosion behavior were investigated in the Mg-Ni-based alloy system by X-ray diffraction (XRD and electrochemical polarization in 0.1 mol/L NaOH solution. Results shows that the GFA of the Mg-Ni-based BMGs can be improved dramatically by the addition of an appropriate amount of Ag; and the addition element Ag can improve the corrosion resistance of Mg-Ni-based bulk metallic glass. The large difference in atomic size and large negative mixing enthalpy in alloy system can contribute to the high GFA. The addition element Ag improves the forming speed and the stability of the passive film, which is helpful to decrease the passivation current density and to improve the corrosion resistance of Mg-Ni-based bulk metallic glass.

  2. Dependence of glass-forming ability on starting compositions in Y2O3–Al2O3–SiO2 system

    Directory of Open Access Journals (Sweden)

    Yixiang Chen

    2011-09-01

    Full Text Available The dependence of glass-forming ability on starting compositions in Y2O3–Al2O3–SiO2 (YAS system has been investigated by melting experiment. Transparent YAS glasses have been prepared under the condition of furnace cooling instead of quenching. It is found that, in the YAS ternary phase diagram, the compositions on the Y3Al5O12–SiO2 line and with 52-68 mol% SiO2 have a higher glass-forming ability to produce pure glass. For the compositions with too much or less SiO2 or with Y/Al = 5/3, 1/1, or 1/3, crystallization occurs with the formation of Y3Al5O12, Y2Si2O7, Al6Si2O13, or SiO2. The densities of the YAS glasses increase with decreasing SiO2 contents and increasing Y/Al ratios, and for the samples with Y/Al = 3/5 there is a good linear relationship between the density and SiO2 content.

  3. In Vitro Screening of the Apatite-Forming Ability, Biointeractivity and Physical Properties of a Tricalcium Silicate Material for Endodontics and Restorative Dentistry

    Directory of Open Access Journals (Sweden)

    Maria Giovanna Gandolfi

    2013-12-01

    Full Text Available Aim: Calcium silicate-based materials are hydraulic self-setting materials with physico-chemical properties suitable for endodontic surgery and good biological/clinical outcomes. The study aim was to evaluate the bio-properties (biointeractivity and apatite-forming ability and selected physical properties (porosity, water sorption, solubility, and setting time of Biodentine, a tricalcium silicate material for endodontics and restorative dentistry, compared to that of ProRoot MTA (Mineral Trioxide Aggregate as gold standard material. Methods: Biodentine and ProRoot MTA pastes were prepared and analyzed for calcium release and alkalinizing activity (3 h–28 days, setting time, water sorption, porosity, solubility, surface microstructure and composition, and apatite-forming ability in simulated body fluid. Results: Biodentine showed higher calcium release, alkalinizing activity, and solubility but higher open and apparent porosity, water sorption, and a markedly shorter setting time. Calcium phosphate (CaP deposits were noted on material surfaces after short ageing times. A CaP coating composed of spherulites was detected after 28 days. The thickness, continuity, and Ca/P ratio of the coating differed markedly between the materials. Biodentine showed a coating composed by denser but smaller spherulites, while ProRoot MTA showed large but less dense aggregates of spherulitic deposits. Conclusions: Biodentine showed a pronounced ability to release calcium and extended alkalinizing activity interlinked with its noticeable porosity, water sorption, and solubility: open porosities provide a broad wet biointeractive surface for the release of the calcium and hydroxyl ions involved in the formation of a CaP mineral. Biodentine is a biointeractive tricalcium silicate material with interesting chemical-physical properties and represents a fast-setting alternative to the conventional calcium silicate MTA-like cements.

  4. Evaluation of the biofilm forming ability and its associated genes in Staphylococcus species isolates from bovine mastitis in Argentinean dairy farms.

    Science.gov (United States)

    Felipe, Verónica; Morgante, Carolina A; Somale, Paola S; Varroni, Florencia; Zingaretti, María L; Bachetti, Romina A; Correa, Silvia G; Porporatto, Carina

    2017-03-01

    Staphylococcus aureus and coagulase-negative staphylococci (CNS) are important causes of intramammary infection in dairy cattle, and their ability to produce biofilm is considered an important virulence property in the pathogenesis of mastitis. However, the published date on mechanisms and factors involved in infection persistence in the mammary gland remains unclear. The aim of this study was to investigate whether the main Staphylococcus species involved in bovine intramammary infections possess specific characteristics that promote colonization of the udder. We evaluated the biofilm-forming ability and distribution of adhesion- and biofilm-associated genes of Staphylococcus spp. isolated from bovine mastitis infected animals in Argentinean dairy farms. For this purpose, the phenotypic biofilm formation ability of 209 Staphylococcus spp. from bovine mastitis was investigated. All isolates produced biofilm in vitro, being 35,0% and 45,0% of the 127 S. aureus or 51,0% and 29,0% of the 82 CNS strong and moderate biofilm producers respectively. All S. aureus samples were PCR-positive for icaA, icaD, clfA, clfB and fnbpA genes, 76.3% were positive for fnbpB gene and 11.0% were positive for bap gene. In CNS isolates, the positive rates for icaA and icaD were 73.2%, while for clfA, clfB, fnbpA fnbpB and bap genes the percentage were lower. The results demonstrate that in Staphylococcus spp. biofilm formation, the polysaccharide and the adhesion- and biofilm-associated genes are of overall importance on bovine mastitis in Argentina. Therefore, future works should focus on these pathogenic specific factors for the development of more effective therapies of control, being essential to consider the ability of isolates to produce biofilm. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Yeast Ivy1p Is a Putative I-BAR-domain Protein with pH-sensitive Filament Forming Ability in vitro.

    Science.gov (United States)

    Itoh, Yuzuru; Kida, Kazuki; Hanawa-Suetsugu, Kyoko; Suetsugu, Shiro

    2016-01-01

    Bin-Amphiphysin-Rvs161/167 (BAR) domains mold lipid bilayer membranes into tubules, by forming a spiral polymer on the membrane. Most BAR domains are thought to be involved in forming membrane invaginations through their concave membrane binding surfaces, whereas some members have convex membrane binding surfaces, and thereby mold membranes into protrusions. The BAR domains with a convex surface form a subtype called the inverse BAR (I-BAR) domain or IRSp53-MIM-homology domain (IMD). Although the mammalian I-BAR domains have been studied, those from other organisms remain elusive. Here, we found putative I-BAR domains in Fungi and animal-like unicellular organisms. The fungal protein containing the putative I-BAR-domain is known as Ivy1p in yeast, and is reportedly localized in the vacuole. The phylogenetic analysis of the I-BAR domains revealed that the fungal I-BAR-domain containing proteins comprise a distinct group from those containing IRSp53 or MIM. Importantly, Ivy1p formed a polymer with a diameter of approximately 20 nm in vitro, without a lipid membrane. The filaments were formed at neutral pH, but disassembled when pH was reverted to basic. Moreover, Ivy1p and the I-BAR domain expressed in mammalian HeLa cells was localized at a vacuole-like structure as filaments as revealed by super-resolved microscopy. These data indicate the pH-sensitive polymer forming ability and the functional conservation of Ivy1p in eukaryotic cells.

  6. Antibiotic resistance, ability to form biofilm and susceptibility to copper alloys of selected staphylococcal strains isolated from touch surfaces in Polish hospital wards

    Directory of Open Access Journals (Sweden)

    Anna Różańska

    2017-08-01

    Full Text Available Abstract Background Despite the employment of sanitary regimes, contact transmission of the aetiological agents of hospital infections is still exceedingly common. The issue of microbe transmission becomes particularly important when facing multidrug-resistant microorganisms such as methicillin-resistant staphylococci. In the case of deficiencies in cleaning and disinfection procedures, hospital equipment made of copper alloys can play an important role, complementing traditional hospital hygiene procedures. The objective of this study was to characterize staphylococcal strains isolated from touch surfaces in Polish hospital wards in terms of their drug resistance, ability to form biofilm and susceptibility to antimicrobial activity of copper alloys. Methods The materials for the study were 95 staphylococcal strains isolated from touch surfaces in 13 different hospital wards from Małopolska province (the south of Poland. Phenotypic and genotypic antibiotic resistance were checked for erythromycin, clindamycin, gentamycin, ciprofloxacin, trimethoprim/sulfamethoxazole and mupirocin. Biofilm formation ability for the tested strains was checked with the use of culture on Congo red agar. Susceptibility to copper, tin bronze, brass and new silver was tested using a modification of the Japanese standard. Results Over 67% of the analysed staphylococcal strains were methicillin-resistant (MR. Four strains were resistant to all of the tested antibiotics, and 14 were resistant to all except mupirocin. Strains classified as MR had significantly increased resistance to the remaining antibiotic groups. About one-third of the analysed strains revealed biofilm-forming ability. Among the majority of species, biofilm-forming and non-biofilm-forming strains were distributed evenly; in the case of S. haemolyticus only, negative strains accounted for 92.8%. Susceptibility to copper alloys was different between strains and rather lower than in the case of the SA

  7. Changes in glass formation and glass forming ability of Nd2Fe14B by the addition of TiC

    International Nuclear Information System (INIS)

    Branagan, D.J.; Iowa State Univ. of Science and Technology, Ames, IA; McCallum, R.W.; Iowa State Univ. of Science and Technology, Ames, IA

    1996-01-01

    The glass forming ability (GFA) of a stoichiometric Nd 2 Fe 14 B alloy modified with TiC additions was studied. Structural, magnetic, and thermal measurements of as-quenched melt-spun ribbons indicate increasing enhancement of GFA with increasing amounts of TiC addition. The limit of the glass formation range and the amount of glass formed at a particular cooling rate also increased with TiC addition. Enhanced GFA was concurrent with changes in the intrinsic properties of the glass. The crystallization temperature, as well as the transformation rate of crystallization, was raised by TiC addition. The intrinsic magnetic properties of the glass were changed with reductions in saturation magnetization and Curie temperature T c with increasing amounts of TiC addition. The intrinsic glass changes were related to changes in the local short range order of the glass and are consistent with a reduction in free volume and an increased packing efficiency. These changes in local structure of the glass increase the glass stability, which means that less undercooling is needed to prevent crystallization. Thus, at a particular cooling rate, a higher percentage of glass will be formed and the GFA is increased. (orig.)

  8. Behavioral Modulation of Infestation by Varroa destructor in Bee Colonies. Implications for Colony Stability.

    Science.gov (United States)

    de Figueiró Santos, Joyce; Coelho, Flávio Codeço; Bliman, Pierre-Alexandre

    2016-01-01

    Colony Collapse Disorder (CCD) has become a global problem for beekeepers and for the crops that depend on bee pollination. While many factors are known to increase the risk of colony collapse, the ectoparasitic mite Varroa destructor is considered to be the most serious one. Although this mite is unlikely to cause the collapse of hives itself, it is the vector for many viral diseases which are among the likely causes for Colony Collapse Disorder. The effects of V. destructor infestation differ from one part of the world to another, with greater morbidity and higher colony losses in European honey bees (EHB) in Europe, Asia and North America. Although this mite has been present in Brazil for many years, there have been no reports of colony losses amongst Africanized Honey Bees (AHB). Studies carried out in Mexico have highlighted different behavioral responses by the AHB to the presence of the mite, notably as far as grooming and hygienic behavior are concerned. Could these explain why the AHB are less susceptible to Colony Collapse Disorder? In order to answer this question, we have developed a mathematical model of the infestation dynamics to analyze the role of resistance behavior by bees in the overall health of the colony, and as a consequence, its ability to face epidemiological challenges.

  9. Behavioral Modulation of Infestation by Varroa destructor in Bee Colonies. Implications for Colony Stability.

    Directory of Open Access Journals (Sweden)

    Joyce de Figueiró Santos

    Full Text Available Colony Collapse Disorder (CCD has become a global problem for beekeepers and for the crops that depend on bee pollination. While many factors are known to increase the risk of colony collapse, the ectoparasitic mite Varroa destructor is considered to be the most serious one. Although this mite is unlikely to cause the collapse of hives itself, it is the vector for many viral diseases which are among the likely causes for Colony Collapse Disorder. The effects of V. destructor infestation differ from one part of the world to another, with greater morbidity and higher colony losses in European honey bees (EHB in Europe, Asia and North America. Although this mite has been present in Brazil for many years, there have been no reports of colony losses amongst Africanized Honey Bees (AHB. Studies carried out in Mexico have highlighted different behavioral responses by the AHB to the presence of the mite, notably as far as grooming and hygienic behavior are concerned. Could these explain why the AHB are less susceptible to Colony Collapse Disorder? In order to answer this question, we have developed a mathematical model of the infestation dynamics to analyze the role of resistance behavior by bees in the overall health of the colony, and as a consequence, its ability to face epidemiological challenges.

  10. Intracellular forms of menadione-dependent small-colony variants of methicillin-resistant Staphylococcus aureus are hypersusceptible to β-lactams in a THP-1 cell model due to cooperation between vacuolar acidic pH and oxidant species.

    Science.gov (United States)

    Garcia, Laetitia G; Lemaire, Sandrine; Kahl, Barbara C; Becker, Karsten; Proctor, Richard A; Tulkens, Paul M; Van Bambeke, Françoise

    2012-12-01

    Phagocytosed methicillin-resistant Staphylococcus aureus (MRSA) are susceptible to β-lactams because of an acid-induced conformational change of penicillin-binding protein (PBP) 2a within phagolysosomes. We have examined whether this mechanism applies to menD and hemB small-colony variants (SCVs) of the COL MRSA strain, using cloxacillin, meropenem, doripenem, and vancomycin as comparator. Intracellularly, the change in cfu from post-phagocytosis inoculum was measured after 24 h of incubation with antibiotics combined or not with N-acetylcysteine (NAC; oxidant species scavenger); the relative potency (C(s)) was calculated from the Hill equation of concentration-response curves. Extracellularly, the effect of a pre-incubation with H(2)O(2) was determined on MICs and killing at pH 7.4 and 5.5. Intracellularly, the β-lactam C(s) was similar for the COL strain and the hemB mutant and not modified or slightly decreased (2- to 16-fold) by NAC. In contrast, the C(s) was 100- to 900-fold lower for the menD mutant, but similar to that for the COL strain when NAC was present. Extracellularly, β-lactam MICs were markedly reduced at pH 5.5 for the parental strain and the haemin-supplemented hemB mutant, with limited additional effect of pre-incubation with H(2)O(2). In contrast, MICs remained elevated at pH 5.5 for the menD mutant (supplemented with menadione sodium bisulphite or not), but were 7-10 dilutions lower after pre-incubation with H(2)O(2). Vancomycin MICs were unaltered in all conditions, with no marked effect of NAC on C(s). Cooperation between acidic pH and oxidant species confers high potency to β-lactams against intracellular forms of menD SCVs of MRSA.

  11. Effect of Yttrium Addition on Glass-Forming Ability and Magnetic Properties of Fe–Co–B–Si–Nb Bulk Metallic Glass

    Directory of Open Access Journals (Sweden)

    Teruo Bitoh

    2015-06-01

    Full Text Available The glass-forming ability (GFA and the magnetic properties of the [(Fe0.5Co0.50.75B0.20Si0.05]96Nb4−xYx bulk metallic glasses (BMGs have been studied. The partial replacement of Nb by Y improves the thermal stability of the glass against crystallization. The saturation mass magnetization (σs exhibits a maximum around 2 at. % Y, and the value of σs of the alloy with 2 at. % Y is 6.5% larger than that of the Y-free alloy. The coercivity shows a tendency to decrease with increasing Y content. These results indicate that the partial replacement of Nb by Y in the Fe–Co–B–Si–Nb BMGs is useful to simultaneous achievement of high GFA, high σs, and good soft magnetic properties.

  12. Involvement of AmpG in mediating a dynamic relationship between serine beta-lactamase induction and biofilm-forming ability of Escherichia coli.

    Science.gov (United States)

    Mallik, Dhriti; Pal, Shilpa; Ghosh, Anindya S

    2018-04-01

    AmpG permease is implicated both in beta-lactamase induction and peptidoglycan recycling in enterobacterial isolates. Here, physiological studies using molecular genetics show that deletion of AmpG permease dramatically increases beta-lactam susceptibility even in the presence of AmpC, TEM-1 and OXA beta-lactamases. Also, there is an appreciable decrease in the biofilm-forming ability of strains lacking this protein. Expression of this permease in excess probably compromises the integrity of the bacterial cells, leading to cell lysis. Based on these results, we propose that AmpG permease may be used as a potential antibiotic target and its suppression could efficiently inhibit both beta-lactamase induction and biofilm formation.

  13. Research of level of formed knowledge, abilities and skills on basket-ball for the students of faculty of physical education.

    Directory of Open Access Journals (Sweden)

    Kovalenko J.A.

    2011-06-01

    Full Text Available The results of a zero control of students of faculty of physical education are presented. The estimation of theoretical knowledge's is conducted, abilities and skills on basket-ball for the students of a 1 course of directions of preparation «Physical education», «Health of man» and «Sport». It is set that the level of their formed at most students of different directions of preparation is insufficient. It is certain that by reason of such position, foremost, there is insufficient preparation and playing practice of students during teaching at general school. A diary is developed on basket-ball for student general schools.

  14. Effect of Si on the glass-forming ability, thermal stability and magnetic properties of Fe-Co-Zr-Mo-W-B alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.-M. [Institute for Metallic Materials, IFW Dresden, P.O. 270016, Dresden D-01171 (Germany); Key Lab of Liquid Structure and Heredity of Materials, Shandong University, Jinan 250061 (China); Gebert, A. [Institute for Metallic Materials, IFW Dresden, P.O. 270016, Dresden D-01171 (Germany)], E-mail: a.gebert@ifw-dresden.de; Roth, S.; Kuehn, U.; Schultz, L. [Institute for Metallic Materials, IFW Dresden, P.O. 270016, Dresden D-01171 (Germany)

    2008-07-14

    This paper presents investigations on the effect of Si on the glass-forming ability, thermal stability and magnetic properties of the Fe-Co-Zr-Mo-W-B samples (group I: Fe{sub 60}Co{sub 8}Zr{sub 10}Mo{sub 5}W{sub 2}B{sub 15-x}Si{sub x}, 1 {<=} x {<=} 4; group II: Fe{sub 60}Co{sub 8}Zr{sub 10-x}Mo{sub 5}W{sub 2}B{sub 15}Si{sub x}, 0 {<=} x {<=} 4; group III: Fe{sub 60}Co{sub 8}Zr{sub 8}Mo{sub 5}W{sub 2}B{sub 17-x}Si{sub x}, 0 {<=} x {<=} 2) prepared by melt spinning, injection casting, and centrifugal casting methods. It is found that the glass-forming ability (GFA) of the alloys in group I is more deteriorated than that in group II, and that the alloys in group III can be cast into the rods of 1-3 mm diameter without crystalline reflections in their XRD patterns. For the amorphous ribbons and rods, a non-monotonic change of the nearest neighbour distance r{sub 1} with increasing Si content c{sub Si} was detected, which is parallel to that of the glass transition and crystallization temperatures T{sub g} and T{sub x}, but opposite to that of the magnetization at room temperature M{sub RT} and the Curie temperature T{sub c}. This correlation can be interpreted by a structure model presuming that iron atoms appear simultaneously in two types of local structures in the amorphous samples.

  15. Teaching Form as Form

    DEFF Research Database (Denmark)

    Keiding, Tina Bering

    2012-01-01

    understanding of form per se, or, to use an expression from this text, of form as form. This challenge can be reduced to one question: how can design teaching support students in achieving not only the ability to recognize and describe different form-related concepts in existing design (i.e. analytical...

  16. Post-Colonial Theory and Action Research

    Directory of Open Access Journals (Sweden)

    Jim Parsons

    2011-02-01

    Full Text Available This essay explores connections between post-colonial theory and action research. Post-colonial theory is committed to addressing the plague of colonialism. Action research, at its core, promises to problematize uncontested ‘colonial’ hegemonies of any form. Both post-colonial theory and action research engage dialogic, critically reflective and collaborative values to offer a fuller range of human wisdom. The authors contend that post-colonialism theory calls for justice and seeks to speak to social and psychological suffering, exploitation, violence and enslavement done to the powerless victims of colonization around the world by challenging the superiority of dominant perspectives and seeking to re-position and empower the marginalized and subordinated. In similar ways, action research works to eradicate oppression, powerlessness and worthlessness by affirming solidarity with the oppressed, helping humans move from passive to active and by fundamentally reshaping power. Because both post-colonial theory and action research position the insider or oppressed in an ethic of efficacy, it values community, relationships, communication and equality, and is committed to reciprocity, reflexivity and reflection. Thus, both hold the potential to help reconstruct conditions for a more democratic and just society

  17. Post-Colonial Theory and Action Research

    Directory of Open Access Journals (Sweden)

    Jim B. Parsons

    2011-04-01

    Full Text Available This essay explores connections between post-colonial theory and action research. Post-colonial theory is committed to addressing the plague of colonialism. Action research, at its core, promises to problematize uncontested ‘colonial’ hegemonies of any form. Both post-colonial theory and action research engage dialogic, critically reflective and collaborative values to offer a fuller range of human wisdom. The authors contend that post-colonialism theory calls for justice and seeks to speak to social and psychological suffering, exploitation, violence and enslavement done to the powerless victims of colonization around the world by challenging the superiority of dominant perspectives and seeking to re-position and empower the marginalized and subordinated. In similar ways, action research works to eradicate oppression, powerlessness and worthlessness by affirming solidarity with the oppressed, helping humans move from passive to active and by fundamentally reshaping power. Because both post-colonial theory and action research position the insider or oppressed in an ethic of efficacy, it values community, relationships, communication and equality, and is committed to reciprocity, reflexivity and reflection. Thus, both hold the potential to help reconstruct conditions for a more democratic and just society.

  18. Molecular Insight into Human Lysozyme and Its Ability to Form Amyloid Fibrils in High Concentrations of Sodium Dodecyl Sulfate: A View from Molecular Dynamics Simulations.

    Directory of Open Access Journals (Sweden)

    Majid Jafari

    Full Text Available Changes in the tertiary structure of proteins and the resultant fibrillary aggregation could result in fatal heredity diseases, such as lysozyme systemic amyloidosis. Human lysozyme is a globular protein with antimicrobial properties with tendencies to fibrillate and hence is known as a fibril-forming protein. Therefore, its behavior under different ambient conditions is of great importance. In this study, we conducted two 500000 ps molecular dynamics (MD simulations of human lysozyme in sodium dodecyl sulfate (SDS at two ambient temperatures. To achieve comparative results, we also performed two 500000 ps human lysozyme MD simulations in pure water as controls. The aim of this study was to provide further molecular insight into all interactions in the lysozyme-SDS complexes and to provide a perspective on the ability of human lysozyme to form amyloid fibrils in the presence of SDS surfactant molecules. SDS, which is an anionic detergent, contains a hydrophobic tail with 12 carbon atoms and a negatively charged head group. The SDS surfactant is known to be a stabilizer for helical structures above the critical micelle concentration (CMC [1]. During the 500000 ps MD simulations, the helical structures were maintained by the SDS surfactant above its CMC at 300 K, while at 370 K, human lysozyme lost most of its helices and gained β-sheets. Therefore, we suggest that future studies investigate the β-amyloid formation of human lysozyme at SDS concentrations above the CMC and at high temperatures.

  19. Evaluation of the ability of commercial wine yeasts to form biofilms (mats) and adhere to plastic: implications for the microbiota of the winery environment.

    Science.gov (United States)

    Tek, Ee Lin; Sundstrom, Joanna F; Gardner, Jennifer M; Oliver, Stephen G; Jiranek, Vladimir

    2018-02-01

    Commercially available active dried wine yeasts are regularly used by winemakers worldwide to achieve reliable fermentations and obtain quality wine. This practice has led to increased evidence of traces of commercial wine yeast in the vineyard, winery and uninoculated musts. The mechanism(s) that enables commercial wine yeast to persist in the winery environment and the influence to native microbial communities on this persistence is poorly understood. This study has investigated the ability of commercial wine yeasts to form biofilms and adhere to plastic. The results indicate that the biofilms formed by commercial yeasts consist of cells with a combination of different lifestyles (replicative and non-replicative) and growth modes including invasive growth, bud elongation, sporulation and a mat sectoring-like phenotype. Invasive growth was greatly enhanced on grape pulp regardless of strain, while adhesion on plastic varied between strains. The findings suggest a possible mechanism that allows commercial yeast to colonise and survive in the winery environment, which may have implications for the indigenous microbiota profile as well as the population profile in uninoculated fermentations if their dissemination is not controlled. © FEMS 2018. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. Colony formation in the cyanobacterium Microcystis.

    Science.gov (United States)

    Xiao, Man; Li, Ming; Reynolds, Colin S

    2018-02-22

    Morphological evolution from a unicellular to multicellular state provides greater opportunities for organisms to attain larger and more complex living forms. As the most common freshwater cyanobacterial genus, Microcystis is a unicellular microorganism, with high phenotypic plasticity, which forms colonies and blooms in lakes and reservoirs worldwide. We conducted a systematic review of field studies from the 1990s to 2017 where Microcystis was dominant. Microcystis was detected as the dominant genus in waterbodies from temperate to subtropical and tropical zones. Unicellular Microcystis spp. can be induced to form colonies by adjusting biotic and abiotic factors in laboratory. Colony formation by cell division has been induced by zooplankton filtrate, high Pb 2+ concentration, the presence of another cyanobacterium (Cylindrospermopsis raciborskii), heterotrophic bacteria, and by low temperature and light intensity. Colony formation by cell adhesion can be induced by zooplankton grazing, high Ca 2+ concentration, and microcystins. We hypothesise that single cells of all Microcystis morphospecies initially form colonies with a similar morphology to those found in the early spring. These colonies gradually change their morphology to that of M. ichthyoblabe, M. wesenbergii and M. aeruginosa with changing environmental conditions. Colony formation provides Microcystis with many ecological advantages, including adaption to varying light, sustained growth under poor nutrient supply, protection from chemical stressors and protection from grazing. These benefits represent passive tactics responding to environmental stress. Microcystis colonies form at the cost of decreased specific growth rates compared with a unicellular habit. Large colony size allows Microcystis to attain rapid floating velocities (maximum recorded for a single colony, ∼ 10.08 m h -1 ) that enable them to develop and maintain a large biomass near the surface of eutrophic lakes, where they may shade

  1. Pretreatment with platelet derived growth factor-BB modulates the ability of costochondral resting zone chondrocytes incorporated into PLA/PGA scaffolds to form new cartilage in vivo.

    Science.gov (United States)

    Lohmann, C H; Schwartz, Z; Niederauer, G G; Carnes, D L; Dean, D D; Boyan, B D

    2000-01-01

    Optimal repair of chondral defects is likely to require both a suitable population of chondrogenic cells and a biodegradable matrix to provide a space-filling structural support during the early stages of cartilage formation. This study examined the ability of chondrocytes to support cartilage formation when incorporated into biodegradable scaffolds constructed from copolymers (PLG) of polylactic acid (PLA) and polyglycolic acid (PGA) and implanted in the calf muscle of nude mice. Scaffolds were fabricated to be more hydrophilic (PLG-H) or were reinforced with 10% PGA fibers (PLG-FR), increasing the stiffness of the implant by 20-fold. Confluent primary cultures of rat costochondral resting zone chondrocytes (RC) were loaded into PLG-H foams and implanted intramuscularly. To determine if growth factor pretreatment could modulate the ability of the cells to form new cartilage, RC cells were pretreated with recombinant human platelet derived growth factor-BB IPDGF-BB) for 4 or 24 h prior to implantation. To assess whether scaffold material properties could affect the ability of chondrogenic cells to form cartilage, RC cells were also loaded into PLG-FR scaffolds. To determine if the scaffolds or treatment with PDGF-BB affected the rate of chondrogenesis, tissue at the implant site was harvested at four and eight weeks post-operatively, fixed, decalcified and embedded in paraffin. Sections were obtained along the transverse plane of the lower leg, stained with haematoxylin and eosin, and then assessed by morphometric analysis for area of cartilage, area of residual implant, and area of fibrous connective tissue formation (fibrosis). Whether or not the cartilage contained hypertrophic cells was also assessed. The amount of residual implant did not change with time in any of the implanted tissues. The area occupied by PLG-FR implants was greater than that occupied by PLG-H implants at both time points. All implants were surrounded by fibrous connective tissue, whether

  2. Synthetic quorum sensing in model microcapsule colonies

    Science.gov (United States)

    Shum, Henry; Balazs, Anna C.

    2017-08-01

    Biological quorum sensing refers to the ability of cells to gauge their population density and collectively initiate a new behavior once a critical density is reached. Designing synthetic materials systems that exhibit quorum sensing-like behavior could enable the fabrication of devices with both self-recognition and self-regulating functionality. Herein, we develop models for a colony of synthetic microcapsules that communicate by producing and releasing signaling molecules. Production of the chemicals is regulated by a biomimetic negative feedback loop, the “repressilator” network. Through theory and simulation, we show that the chemical behavior of such capsules is sensitive to both the density and number of capsules in the colony. For example, decreasing the spacing between a fixed number of capsules can trigger a transition in chemical activity from the steady, repressed state to large-amplitude oscillations in chemical production. Alternatively, for a fixed density, an increase in the number of capsules in the colony can also promote a transition into the oscillatory state. This configuration-dependent behavior of the capsule colony exemplifies quorum-sensing behavior. Using our theoretical model, we predict the transitions from the steady state to oscillatory behavior as a function of the colony size and capsule density.

  3. Specters of Colonialism

    DEFF Research Database (Denmark)

    Muhr, Sara Louise; Azad, Salam

    2013-01-01

    at the same time they always are bound to fail to become ‘Swedish’ because of the same foreign origins. Although Swedish culture – partly by distancing itself from having a colonial past – has successfully built up an image of openness, we argue that without acknowledging and confronting the role...

  4. Glass forming ability of the Al-Ce-Ni system; Avaliacao da capacidade de formacao vitrea do sistema Al-Ce-Ni

    Energy Technology Data Exchange (ETDEWEB)

    Triveno Rios, C. [Engenharia Mecanica, Universidade Federal de Mato Grosso, Rondonopolis, MT (Brazil)], e-mail: triveno@ufmt.br; Surinach, S.; Baro, M.D. [Departamento de Engenharia de Materiais - Universidade Federal de Sao Carlos, SP (Brazil); Bolfarini, C.; Botta, W.J.; Kiminami, C.S. [Departamento de Fisica da Universidade Autonoma de Barcelona, Bellaterra (Spain)

    2010-07-01

    In the present work, the glass forming ability (GFA) and its compositional dependence on Al-Ni-Ce system alloys were investigated in function of several thermal parameters. Rapidly quenched Al{sub 85}Ni{sub 15}-{sub X}Ce{sub X} (X=4,5,6,7,10), Al{sub 90}Ni{sub 5}Ce{sub 5}, Al{sub 89}Ni{sub 2}.{sub 4}Ce{sub 8}.{sub 6}, Al{sub 80}Ni{sub 15.6}Ce{sub 4}.{sub 4} and Al{sub 78}Ni{sub 18.5}Ce{sub 3.5} amorphous ribbons were produced by melt-spinning and the structural transformation during heating was studied using a combination of X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The results showed that the GFA and the thermal stability in the Al-rich corner of Al- Ni-Ce system alloys were enhanced by increasing the solute content and specifically the Ce content (author)

  5. Theoretical Considerations of the Prigogine-Defay Ration with Regard to the Glass-Forming Ability of Drugs from Undercooled Melts

    Energy Technology Data Exchange (ETDEWEB)

    Wyttenbach, Nicole; Kirchmeyer, Wiebke; Alsenz, Jochem; Kuentz, Martin [UASANS

    2016-01-26

    Drug behavior in undercooled melts is highly important for pharmaceutics with regard to amorphous solid dispersions, and therefore, categories were recently introduced that differentiate glass formers (GFs) from other drugs that are nonglass formers (nGFs). The present study is based on the assumption that molecular properties relevant for the so-called Prigogine–Defay (PD) ratio would be indicative of a drug’s glass-forming ability. The PD ratio depends in theory on the entropy of fusion and molar volume. Experimental data were gathered from a broad set of pharmaceutical compounds (n = 54) using differential scanning calorimetry. The obtained entropy of fusion and molar volume were indeed found to significantly discriminate GFs from nGFs. In a next step, the entropy of fusion was predicted by different in silico methods. A first group contribution method provided rather unreliable estimates for the entropy of fusion, while an alternative in silico approach seemed more promising for drug categorization. Thus, a significant discrimination model employed molar volume, a so-called effective hydrogen bond number, and effective number of torsional bonds (or torsional units) to categorize GFs and nGFs (p ≤ 0.0000). The results led to new insights into drug vitrification and to practical rules of thumb. The latter may serve as guidance in pharmaceutical profiling and early formulation development with respect to amorphous drug formulations.

  6. Thermal stability and glass-forming ability of amorphous Nd-Al-TM (TM=Fe, Co, Ni or Cu) alloys

    International Nuclear Information System (INIS)

    Inoue, A.; Zhang Tao

    1997-01-01

    Bulk amorphous alloys were prepared for Nd 70 Al 10 TM 20 and Nd 60 Al 10 TM 30 (TM=Fe or Co) alloys by copper mold casting. The maximum sample thickness for glass formation reaches 15 mm for the Nd-Al-Fe alloys and 5 mm for the Nd-Al-Co alloys. A significant difference in the phase transition upon heating is recognized between the Fe- and Co-containing alloys. No glass transition before crystallization is observed for the Nd-Al-Fe alloys, but the Nd-Al-Co alloys exhibit the glass transition. The ΔT x (=T x -T g ) and T g /T m are 40-55 K and 0.65-0.67, respectively, for the latter alloys. The absence of supercooled liquid for the former alloys is different from those for all bulk amorphous alloys reported up to date. The T x /T m and ΔT m (=T m -T x ) are 0.85-0.89 and 88-137 K, respectively, for the Nd-Al-Fe alloys and, hence, the large glass-forming ability is presumably due to the high T x /T m and small ΔT m values. (orig.)

  7. Influence of substitution of La by Ce on the glass forming ability and crystallization behavior of Al–Ni–La alloys

    International Nuclear Information System (INIS)

    Zhang, Z.; Xiong, X.Z.; Zhou, W.; Li, J.F.

    2013-01-01

    Highlights: •Wedge-shaped samples were suction cast with casting conditions controlled. •Partial substitution of La by Ce decreases the GFA of Al 85.5 Ni 9.5 La 5 . •Partial substitution of La by Ce increases the GFA of other Al–Ni–La alloys. •The GFA was analyzed from the thermodynamic and topological points of view. -- Abstract: Wedge-shaped samples of Al–Ni–(La–Ce) alloys were suction cast under an identical preparation condition, and their glass forming abilities (GFAs) and crystallization behaviors were compared. It was revealed that the partial substitution of La by Ce decreases the GFA of Al 85.5 Ni 9.5 La 5 alloy but increases the GFAs of Al 87.5 Ni 7.5 La 5 , Al 86.5 Ni 8.5 La 5 , Al 86 Ni 9 La 5 and Al 86 Ni 9.5 La 4.5 alloys. Meantime the crystallization behavior significantly changes. The optimal substitution content of La for glass formation depends on the composition of the base alloy. The lower the Ni content in the base alloy, the more the La content to be substituted. The GFA change with the substitution content is determined by the atomic packing efficiencies of the La (Ce)-centered clusters

  8. Persistent and transient Listeria monocytogenes strains from retail deli environments vary in their ability to adhere and form biofilms and rarely have inlA premature stop codons.

    Science.gov (United States)

    Wang, Jingjin; Ray, Andrea J; Hammons, Susan R; Oliver, Haley F

    2015-02-01

    Based on recent risk assessments, up to 83% of listeriosis cases from deli meat in the United States are predicted to be from ready-to-eat deli meats contaminated during processing at retail grocery stores. Listeria monocytogenes is known to use sanitizer tolerance and biofilm formation to survive, but interplay of these mechanisms along with virulence potential and persistence mechanisms specific to deli environments had yet to be elucidated. In this study, 442 isolates from food and nonfood contact surfaces in 30 retail delis over 9 months were tested for inlA premature stop codons (PMSCs); inlA encodes InlA, which is necessary to cause listeriosis. A total of 96 isolates, composed of 23 persistent and 73 transient strains, were tested for adhesion and biofilm-forming ability and sanitizer tolerance. Only 10/442 isolates had inlA PMSCs (pdelis with other persistent strains. Most (7/10) PMSC-containing isolates were collected from food contact surfaces (pdelis (p<0.05). Persistent strains had enhanced adhesion on day 1 of a 5-day adhesion-biofilm formation assay. However, there was no significant difference in sanitizer tolerance between persistent and transient strains. Results suggest that foods contaminated with persistent L. monocytogenes strains from the retail environment are (1) likely to have wild-type virulence potential and (2) may persist due to increased adhesion and biofilm formation capacity rather than sanitizer tolerance, thus posing a significant public health risk.

  9. Effects of Nb addition on icosahedral quasicrystalline phase formation and glass-forming ability of Zr--Ni--Cu--Al metallic glasses

    International Nuclear Information System (INIS)

    Fan, Cang; Li, Chunfei; Inoue, Akihisa; Haas, Volker

    2001-01-01

    This work shows that the crystallization process of Zr--Ni--Cu--Al metallic glass is greatly influenced by adding Nb as an alloying element. Based on the results of the differential scanning calorimetry experiments for metallic glasses Zr 69-x Nb x Ni 10 Cu 12 Al 9 (x=0--15at.%), the crystallization process takes place through two individual stages. For Zr 69 Ni 10 Cu 12 Al 9 (x=0), metastable hexagonal ω-Zr and a small fraction of tetragonal Zr 2 Cu are precipitated upon completion of the first exothermic reaction. Contrary to this alloy, the precipitation of a nanoquasicrystalline phase is detected when 5--10 at.% Nb is added. Furthermore, the crystallization temperature T x , supercooled liquid region ΔT x and reduced temperature T g /T L (T g is the glass transition temperature, T L the liquidus temperature) increase with increasing Nb content. These results indicate that adding Nb content to Zr--Ni--Cu--Al metallic glasses not only induces quasicrystalline phase formation, but also enhances glass-forming ability. Copyright 2001 American Institute of Physics

  10. Electronic-structure origin of the glass-forming ability and magnetic properties in Fe–RE–B–Nb bulk metallic glasses

    International Nuclear Information System (INIS)

    Li, J.W.; Estévez, D.; Jiang, K.M.; Yang, W.M.; Man, Q.K.; Chang, C.T.; Wang, X.M.

    2014-01-01

    Highlights: • Relation between GFA and electronic structure of RE doped BMGs is investigated. • Tm enhances RE–B bonds and decreases the density of states near the Fermi level. • Magnetic properties of the alloys are related to the electronic structure of RE. - Abstract: (Fe 0.71 RE 0.05 B 0.24 ) 96 Nb 4 (RE = Gd, Tb, Ho, Er, Tm) bulk metallic glasses (BMGs) were found exhibiting excellent glass-forming ability (GFA) with critical diameters ranging from 3.5 to 6.5 mm, and high compressive fracture strength larger than 4300 MPa. Moreover, they displayed good soft-magnetic properties with saturation magnetic flux density of 0.71–0.87 T, coercive force of 1.23–39.76 A/m and effective permeability of 1500–12,740 at 1 kHz. X-ray photoelectron spectroscopy was performed to clarify the origin of the excellent GFA from the viewpoint of electronic structure. It was found that the Tm doped alloy displayed unique electronic structure including the deepest core-level binding energy, the most numerous RE–B bonds and the minimum density of states near the Fermi level, making this alloy the best glass former. The various trends noticed in the magnetic properties were ascribed mainly to the differences in the magnetic anisotropy and magnetic moment of RE elements

  11. Effect of Mo-Fe substitution on glass forming ability, thermal stability, and hardness of Fe-C-B-Mo-Cr-W bulk amorphous alloys

    Energy Technology Data Exchange (ETDEWEB)

    Khalifa, Hesham E.; Cheney, Justin L. [University of California, San Diego Materials Science and Engineering Program, 9500 Gilman Drive, La Jolla, CA 92093-0411 (United States); Vecchio, Kenneth S. [University of California, San Diego Department of NanoEngineering, 9500 Gilman Drive, La Jolla, CA 92093-0411 (United States)], E-mail: kvecchio@ucsd.edu

    2008-08-25

    Amorphous Fe{sub 67-x}C{sub 10}B{sub 9}Mo{sub 7+x}Cr{sub 4}W{sub 3} (x = 1-7 at.%) plates with 640 {mu}m thickness were prepared by copper mold casting. The thermal properties and microstructural development during heat treatments were investigated by a combination of differential scanning calorimetry (DSC), differential thermal analysis, and X-ray diffractometry (XRD). The glass forming ability (GFA) and activation energy for crystallization have a distinct dependence on Mo content. Fe{sub 62}C{sub 10}B{sub 9}Mo{sub 12}Cr{sub 4}W{sub 3} is the best glass former in this study, demonstrating a supercooled liquid region, {delta}T{sub x} = 51 K, and an activation energy for crystallization, Q = 453 kJ/mol. The GFA of alloys in this system was governed by elastic strain optimization resulting directly from the variation in Mo content. Heat treatments were performed to demonstrate resistance to crystallization under typical processing conditions. Alloys in this system exhibited a three-phase evolution during crystallization. A second set of heat treatments was performed to identify each phase. Hardness data was collected at each of the heat treatment conditions, and a bulk metallic glasses (BMG)-derived composite containing a Mo-rich phase exhibited Vickers Hardness in excess of 2000. The fully amorphous alloys had an average hardness approaching 1500.

  12. Preparation and properties of calcium-silicate filled resins for dental restoration. Part I: chemical-physical characterization and apatite-forming ability.

    Science.gov (United States)

    Profeta, Andrea Corrado

    2014-11-01

    The aim of this study was to measure dimensional changes due to hygroscopic expansion and the bioactivity of two experimental methacrylate-based dental adhesives either incorporating Bioglass 45S5 (3-E&RA/BG) or MTA (3-E&RA/WMTA). 3-E&RA/BG, 3-E&RA/WMTA and a control filler-free resin blend (3-E&RA) were formulated from commercially available monomers. Water sorption (WS) and solubility (SL) behaviour were evaluated by weighing material disks at noted intervals; the relationship between degree of hydration and the glass transition temperature (Tg) was investigated by using differential scanning calorimetry (DSC). In vitro apatite-forming ability as a function of soaking time in phosphate-containing solutions was also determined. Kruskal-Wallis analysis of variance (ANOVA) was used to evaluate differences between groups for maximum WS, SL, net water uptake and the percentage change in Tg values. Post-ANOVA pair-wise comparisons were conducted using Mann-Whitney-U tests. 3-E&RA/BG and 3-E&RA/WMTA exhibited values of maximum WS and net water uptake that were significantly higher when compared to 3-E&RA. However, no statistically significant differences were observed in terms of SL between all the adhesives. The addition of the Bioglass 45S5 and MTA to the 3-E&RA showed no reduction of the Tg after 60 days of storage in deionized water. ATR Fourier Transform Infrared Spectroscopy (ATR-FTIR) of the filled resin disks soaked in DPBS for 60 days showed the presence of carbonate ions in different chemical phases. Dentine bonding agents comprising calcium-silicates are not inert materials in a simulated oral environment and apatite formation may occur in the intra-oral conditions. A bioactive dental material which forms apatite on the surface would have several benefits including closure of gaps forming at the resin-dentine interface and potentially better bond strength over time (less degradation of bond).

  13. Effect of fluid motion on colony formation in Microcystis aeruginosa

    Directory of Open Access Journals (Sweden)

    Lin Li

    2013-01-01

    Full Text Available Microcystis aeruginosa, generally occurring in large colonies under natural conditions, mainly exists as single cells in laboratory cultures. The mechanisms involved in colony formation in Microcystis aeruginosa and their roles in algal blooms remain unknown. In this study, based on previous research findings that fluid motion may stimulate the colony formation in green algae, culture experiments were conducted under axenic conditions in a circular water chamber where the flow rate, temperature, light, and nutrients were controlled. The number of cells of Microcystis aeruginosa, the number of cells per colony, and the colonial characteristics in various growth phases were observed and measured. The results indicated that the colony formation in Microcystis aeruginosa, which was not observed under stagnant conditions, was evident when there was fluid motion, with the number of cells per largest colony reaching 120 and the proportion of the number of cells in colonial form to the total number of cells and the mean number of cells per colony reaching their peak values at a flow rate of 35 cm/s. Based on the analysis of colony formation process, fluid motion stimulates the colony formation in Microcystis aeruginosa in the lag growth phase, while flushes and disaggregates the colonies in the exponential growth phase. The stimulation effect in the lag growth phase may be attributable to the involvement of fluid motion in a series of physiological processes, including the uptake of trace elements and the synthesis and secretion of polysaccharides. In addition, the experimental groups exhibiting typical colonial characteristics in the lag growth phase were found to have higher cell biomass in the later phase.

  14. Kant's Second Thoughts on Colonialism

    NARCIS (Netherlands)

    Kleingeld, Pauline; Flikschuh, Katrin; Ypi, Lea

    2014-01-01

    Kant is widely regarded as a fierce critic of colonialism. In Toward Perpetual Peace and the Metaphysics of Morals, for example, he forcefully condemns European conduct in the colonies as a flagrant violation of the principles of right. His earlier views on colonialism have not yet received much

  15. GENERAL AND SPECIFIC COMBINING ABILITY OF INITIAL PARENTAL FORMS IN TOMATO FOR COMPLEX OF ECONOMICALLY VALUABLE TRAITS TO DEVELOP HYBRIDS F1 OF CHERRY AND COCKTAIL TYPES

    Directory of Open Access Journals (Sweden)

    R. K. Rechets

    2017-01-01

    Full Text Available Results of estimation of general and specific combining ability of male and female parental tomato forms were given for complex of traits. The estimation was carried out according to incomplete diallel crosses 15x15. Such varities   as   ‘Trapeza’,  Rosovaya  kapelka’,  ‘Seniorita’, ‘Ocharovanie’,  ‘Tigris’   ‘Vishnya  Zheltaya’  (Gavrish, ‘Denezhnoye Derevo’ (national breeding, and  lines: ‘46/06’,  ‘49/09’,  ‘295/09’,  ‘336/11’,  ‘354/11’,  ‘357/11’, ‘388/09’ (nor, ‘498’ (selection of TARI were used as intial breeding accessions, differing in bush type (determinate and indeterminate, duration of vegetative phase (ultraearly,  early, medium early, middle-ripening, fruit  shape (rounded, oval, fruit color (red, pink, black, orange, tiger and with the gene nor, fruit weight (10 g. and more, brush structure (dense, friable. As a results, ‘Trapeza’, ‘Vishnya Zheltaya’, ‘Ocharovaniye’, ‘Seniorita’, and lines: ‘295/10’, ‘49/09’,  ‘498’,  ‘357/11’,  ‘354/11’,  ‘388/09’  (nor were selected and recommended to be used in breeding program for development of heterotic hybrids with high fruit setting and generative bush type. The promising hybrids F1 with high constants of specific combining ability for a complex of economically valuable traits have been observed. Because of different lines and accessions were used in crossings, these hybrids varied in internode length of cluster type, classical or shorten; rounded or oval fruit shape; fruit  color, red (F1   combinations ‘354/11’ х ‘Seniorita’, ‘Trapeza’ х  ‘L.49/09’,  L.  ‘49/09’  х  L.354/11, pink (F1 combination ‘Rosovaya Kapelka’ х ‘L.354/11’, yellow (F1 combination ‘Ocharovaniye’ х  ‘Vishiya Zheltaya’, deep brown (F1 combination  ‘L.357/11’ х ‘L.354/11’.

  16. Ireland – a test case of Post-colonialism / Post colonialism

    Directory of Open Access Journals (Sweden)

    Brenda Murray

    2006-05-01

    Full Text Available Contextualisation This review attempts to set the stage for post-colonial theorising, in the light of alternative representations of ‘whiteness’, on issues of gender, race and language within the discourse of equality. In this paper Ireland and the Irish provide a backdrop against which the nature and impact of colonialism on the colonised and the coloniser are explored. Many challenging questions emerge about the ideological basis of post colonial theory, not least when traditional paradigms of racism, as conveyed by the black / white dichotomy, are examined: Ireland presents a context, it is argued, where subjugation is of white on white. Linked to this is the language of the coloniser, a powerful hegemonic force which, in some situations, has been nurtured by the colonised and later developed into a text which is unique, producing a new literature which, it is asserted, truly invokes the ‘post colonial’. Abstract: Post-colonialism – essentially a critique of colonialism, is characterised by a process of disengagement from the colonial epoch and has taken many forms. In this article a set of phenomena are examined that have become inscribed in the cultures of the colonised with a view to identifying alternative cultural origins and dispositions recovered in this post-colonial era. Ireland and the Irish provide the background context of this exploration into perspectives generated by the peripheral or post-colonial nations. Globalisation, too, has had a role to play in the increasing de-territorialisation of communities as a result of cross-frontier mobility, increased intra-community mobility and new communication technologies. A critical reflection on the process of disengagement leads the author to conclude that we must come to recognise new cultural forms which are accepting of a heterogeneous and inclusive society: one which is not characterised by difference.

  17. Influence of substitution of La by Ce on the glass forming ability and crystallization behavior of Al–Ni–La alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z.; Xiong, X.Z.; Zhou, W.; Li, J.F., E-mail: jfli@sjtu.edu.cn

    2013-11-05

    Highlights: •Wedge-shaped samples were suction cast with casting conditions controlled. •Partial substitution of La by Ce decreases the GFA of Al{sub 85.5}Ni{sub 9.5}La{sub 5}. •Partial substitution of La by Ce increases the GFA of other Al–Ni–La alloys. •The GFA was analyzed from the thermodynamic and topological points of view. -- Abstract: Wedge-shaped samples of Al–Ni–(La–Ce) alloys were suction cast under an identical preparation condition, and their glass forming abilities (GFAs) and crystallization behaviors were compared. It was revealed that the partial substitution of La by Ce decreases the GFA of Al{sub 85.5}Ni{sub 9.5}La{sub 5} alloy but increases the GFAs of Al{sub 87.5}Ni{sub 7.5}La{sub 5}, Al{sub 86.5}Ni{sub 8.5}La{sub 5}, Al{sub 86}Ni{sub 9}La{sub 5} and Al{sub 86}Ni{sub 9.5}La{sub 4.5} alloys. Meantime the crystallization behavior significantly changes. The optimal substitution content of La for glass formation depends on the composition of the base alloy. The lower the Ni content in the base alloy, the more the La content to be substituted. The GFA change with the substitution content is determined by the atomic packing efficiencies of the La (Ce)-centered clusters.

  18. Knock down of HIF-1α in glioma cells reduces migration in vitro and invasion in vivo and impairs their ability to form tumor spheres

    Directory of Open Access Journals (Sweden)

    Esencay Mine

    2010-06-01

    Full Text Available Abstract Background Glioblastoma (GBM is the most common and malignant primary intracranial human neoplasm. GBMs are characterized by the presence of extensive areas of necrosis and hypoxia. Hypoxia and its master regulator, hypoxia inducible factor 1 (HIF-1 play a key role in glioma invasion. Results To further elucidate the functional role of HIF-1α in glioma cell migration in vitro and in invasion in vivo, we used a shRNA approach to knock down HIF-1α expression complemented with genome-wide expression profiling, performed in both normoxic and hypoxic conditions. Our data show that knock down of HIF-1α in glioma cells significantly impairs their migration in vitro as well as their ability to invade into the brain parenchyma in vivo. Next, we assessed the role that HIF-1α plays in maintaining the characteristics of cancer stem cells (CSCs. By using the tumor sphere forming assay, we demonstrate that HIF-1α plays a role in the survival and self-renewal potential of CSCs. Finally, expression profiling experiments in glioma cells provided detailed insight into a broad range of specific biological pathways and processes downstream of HIF-1α. We discuss the role of these processes in the migratory and invasive properties, as well as the stem cell biology of glioblastomas Conclusions Our data show that knock down of HIF-1α in human and murine glioma cells impairs their migration in vitro and their invasion in vivo. In addition, our data suggest that HIF-1α plays a role in the survival and self-renewal potential of CSCs and identify genes that might further elucidate the role of HIF-1α in tumor migration, invasion and stem cell biology.

  19. Artificial bee colony algorithm with dynamic multi-population

    Science.gov (United States)

    Zhang, Ming; Ji, Zhicheng; Wang, Yan

    2017-07-01

    To improve the convergence rate and make a balance between the global search and local turning abilities, this paper proposes a decentralized form of artificial bee colony (ABC) algorithm with dynamic multi-populations by means of fuzzy C-means (FCM) clustering. Each subpopulation periodically enlarges with the same size during the search process, and the overlapping individuals among different subareas work for delivering information acting as exploring the search space with diffusion of solutions. Moreover, a Gaussian-based search equation with redefined local attractor is proposed to further accelerate the diffusion of the best solution and guide the search towards potential areas. Experimental results on a set of benchmarks demonstrate the competitive performance of our proposed approach.

  20. Yeast Colonies: A Model for Studies of Aging, Environmental Adaptation, and Longevity

    Directory of Open Access Journals (Sweden)

    Libuše Váchová

    2012-01-01

    Full Text Available When growing on solid surfaces, yeast, like other microorganisms, develops organized multicellular populations (colonies and biofilms that are composed of differentiated cells with specialized functions. Life within these populations is a prevalent form of microbial existence in natural settings that provides the cells with capabilities to effectively defend against environmental attacks as well as efficiently adapt and survive long periods of starvation and other stresses. Under such circumstances, the fate of an individual yeast cell is subordinated to the profit of the whole population. In the past decade, yeast colonies, with their complicated structure and high complexity that are also developed under laboratory conditions, have become an excellent model for studies of various basic cellular processes such as cell interaction, signaling, and differentiation. In this paper, we summarize current knowledge on the processes related to chronological aging, adaptation, and longevity of a colony cell population and of its differentiated cell constituents. These processes contribute to the colony ability to survive long periods of starvation and mostly differ from the survival strategies of individual yeast cells.

  1. A new quantum inspired chaotic artificial bee colony algorithm for optimal power flow problem

    International Nuclear Information System (INIS)

    Yuan, Xiaohui; Wang, Pengtao; Yuan, Yanbin; Huang, Yuehua; Zhang, Xiaopan

    2015-01-01

    Highlights: • Quantum theory is introduced to artificial bee colony algorithm (ABC) to increase population diversity. • A chaotic local search operator is used to enhance local search ability of ABC. • Quantum inspired chaotic ABC method (QCABC) is proposed to solve optimal power flow. • The feasibility and effectiveness of the proposed QCABC is verified by examples. - Abstract: This paper proposes a new artificial bee colony algorithm with quantum theory and the chaotic local search strategy (QCABC), and uses it to solve the optimal power flow (OPF) problem. Under the quantum computing theory, the QCABC algorithm encodes each individual with quantum bits to form a corresponding quantum bit string. By determining each quantum bits value, we can get the value of the individual. After the scout bee stage of the artificial bee colony algorithm, we begin the chaotic local search in the vicinity of the best individual found so far. Finally, the quantum rotation gate is used to process each quantum bit so that all individuals can update toward the direction of the best individual. The QCABC algorithm is carried out to deal with the OPF problem in the IEEE 30-bus and IEEE 118-bus standard test systems. The results of the QCABC algorithm are compared with other algorithms (artificial bee colony algorithm, genetic algorithm, particle swarm optimization algorithm). The comparison shows that the QCABC algorithm can effectively solve the OPF problem and it can get the better optimal results than those of other algorithms

  2. An improved method for staining cell colonies in clonogenic assays

    OpenAIRE

    Guda, Kishore; Natale, Leanna; Markowitz, Sanford D.

    2007-01-01

    Clonogenic assay is a widely used experimental approach to test for the effects of drugs/genes on the growth and proliferative characteristics of cells in vitro. Accurate quantitation of treatment effects in clonogeneic assays depends on the ability to visualize and count cell colonies precisely. We report a novel method (referred as ETeB) for staining cell colonies grown on plastic and specially coated substrates like collagen. Using colon cancer cell lines grown on plastic and collagen, we ...

  3. Changes in numbers and types of mast cell colony-forming cells in the peritoneal cavity of mice after injection of distilled water: evidence that mast cells suppress differentiation of bone marrow-derived precursors

    International Nuclear Information System (INIS)

    Kanakura, Y.; Kuriu, A.; Waki, N.; Nakano, T.; Asai, H.; Yonezawa, T.; Kitamura, Y.

    1988-01-01

    Two different types of cells in the peritoneal cavity of mice produce mast cell colonies in methylcellulose. Large mast cell colonies are produced by bone marrow-derived precursors resembling lymphoid cells by light microscopy (L-CFU-Mast), whereas medium and small mast cell colonies are produced by morphologically identifiable mast cells (M-CFU-Mast and S-CFU-Mast, respectively). In the present study we eradicated peritoneal mast cells by intraperitoneal (IP) injection of distilled water. The regeneration process was investigated to clarify the relationship between L-CFU-Mast, M-CFU-Mast, and S-CFU-Mast. After injection of distilled water, M-CFU-Mast and S-CFU-Mast disappeared, but L-CFU-Mast increased, and then M-CFU-Mast and S-CFU-Mast appeared, suggesting the presence of a hierarchic relationship. When purified peritoneal mast cells were injected two days after the water injection, the L-CFU-Mast did not increase. In the peritoneal cavity of WBB6F1-+/+ mice that had been lethally irradiated and rescued by bone marrow cells of C57BL/6-bgJ/bgJ (beige, Chediak-Higashi syndrome) mice, L-CFU-Mast were of bgJ/bgJ type, but M-CFU-Mast and S-CFU-Mast were of +/+ type. The injection of distilled water to the radiation chimeras resulted in the development of bgJ/bgJ-type M-CFU-Mast and then S-CFU-Mast. The presence of mast cells appeared to suppress the recruitment of L-CFU-Mast from the bloodstream and to inhibit the differentiation of L-CFU-Mast to M-CFU-Mast

  4. HONEY BEE COLONY PHEROMONES

    Directory of Open Access Journals (Sweden)

    M Dražić

    2001-09-01

    Full Text Available ABSTRACT Pheromones are chemicals produced as liquids by specialised cells or glands and transmitted into the environment as liquids or gases. In contrary to hormones, which are excreted in organism and have effect exclusively on organism that produced them, pheromones are excreted outside organism and effect on different individuals of the same species. Pheromones mediate nearly all aspects of honeybee colony life including social defence, brood care, mating, orientation, foraging and reproduction. Pheromone investigation has high economic importance. With use of pheromones it is possible to manipulate with pest insects on crops or to direct honeybees during pollination on target plants.

  5. Survey of post-gamma-ray colony-forming ability, DNA metabolism and oncogene status in non-malignant fibroblast strains from cancer-prone families and individual cancer patients

    International Nuclear Information System (INIS)

    Paterson, M.C.; Aubin, R.A.; Fourney, R.M.; Mirzayans, R.

    1989-01-01

    The in vitro radiobiological studies described here have focused on highly selected individuals comprising some of the most likely cases of predisposition to radiogenic cancer ascertained to date. Our results argue against the existence, within the general population, of quantitatively significant subgroups sensitive to the carcinogenic effects of ubiquitous low-level radiation. In fact, of the forty-six cancer-susceptible conditions examined, only four (i.e. members of the cancer-prone lineage in two kindreds and two isolated patients), exhibited abnormal cellular response to γ-rays in vitro. These findings indicate that in this unprecedented collection of high cancer risk conditions, the incidence of abnormal radiation cytotoxicity is only about two-fold above that found in a randomly selected group of age-matched healthy subjects (i.e, about 9% [4/46 conditions] versus about 5% [1/21 volunteers]). This interpretation of the data assumes, however, that the post-γ-ray CFA assay performed on cultured dermal fibroblasts is a reliable and sensitive indicator of the donor's susceptibility to develop radiogenic cancer, irrespective of the anatomical site or histological type of the tumour(s). (author)

  6. Analysis of Colonial Currency

    Science.gov (United States)

    Kurkowski, Michael; Cangany, Catherine; Jordan, Louis; Manukyan, Khachatur; Schultz, Zachary; Wiescher, Michael

    2017-09-01

    This project entailed studying the cellulose in paper, the ink, colorants, and other materials used to produce American colonial currency. The technique primarily used in this project was X-Ray Fluorescence Spectroscopy (XRF). XRF mapping was used to provide both elemental analysis of large-scale objects as well as microscopic examination of individual pigment particles in ink, in addition to the inorganic additives used to prepare paper. The combination of elemental mapping with Fourier Transform Infrared (FTIR) and Raman Spectroscopies permits an efficient analysis of the currency. These spectroscopic methods help identify the molecular composition of the pigments. This combination of atomic and molecular analytical techniques provided an in-depth characterization of the paper currency on the macro, micro, and molecular levels. We have identified several of pigments that were used in the preparation of inks and colorants. Also, different inorganic crystals, such as alumina-silicates, have been detected in different papers. The FTIR spectroscopy allowed us to determine the type of cellulose fiber used in the production of paper currency. Our future research will be directed toward revealing important historical relationships between currencies printed throughout the colonies. ISLA Da Vinci Grant.

  7. Seabird Colonies in Western Greenland

    DEFF Research Database (Denmark)

    Boertmann, D.; Mosbech, A.; Falk, K.

    About 1 million seabirds (indvs) breed in 1032 colonies distributed along the coasts of western Greenland (Fig. 1). However, this figure does not include the little auk colonies in Avanersuaq. These colonies are roughly estimated to hold about 20 mill. pairs. All the basic information on seabird...... colonies in Greenland is compiled in a database maintained by NERI-AE. This report presents data on distribution, population numbers and population trends of 19 species of breeding colonial seabirds in western Greenland. Distributions are depicted on maps in Fig. 18-39. It is apparent that the major...... colonies are found in the northern part of the region, viz. Upernavik and Avanersuaq. The numbers of birds recorded in the database for each species are presented in Tab. 4, and on the basis of these figures estimates of the populations in western Greenland are given (Tab. 5). The most numerous species...

  8. Agar Technique for the Cultivation In Vitro of Bone-Marrow Colonies

    Energy Technology Data Exchange (ETDEWEB)

    Metcalf, D. [Walter and Eliza Hall Institute, Royal Melbourne Hospital, Melbourne, VIC (Australia)

    1969-07-15

    In solid-state agar cultures certain haemopoietic cells proliferate and form discrete colonies of 200 - 4000 cells. Colony formation is dependent on stimulation by the colony-stimulating factor, and this is achieved by (1) the use of a cell feeder layer, (2) the addition of conditioned medium, or (3) the addition of human or mouse serum or urine containing the factor. All colonies initially contain granulocytic cells which differentiate from myeloblasts to polymorphs as colony growth proceeds. Later colonies develop a second population of phagocytic mononuclear cells (macrophages). The colony-forming-system is simple, readily quantitated and highly reproducible. Linear dose responses occur between the dose of colony-stimulating factor and the number and size of colonies developing from a standard number of bone-marrow cells. In-vitro colony formation has been achieved with haemopoietic cells of the following species: mouse, rat, hamster, guinea pig, rabbit and human. In the adult mouse, colony-forming cells are located in the bone marrow, spleen and blood and in the embryo, in the yolk sac, liver and spleen. The colony-forming cell appears to be an early member of the granulocytic series. The colony-forming system has been used as a quantitative assay system: (1) to assay levels of colony-stimulating factor in serum and urine and in the chemical- characterization and purification of the factor; and (2) to enumerate the number of colony-forming cells in haemopoietic tissues in response to a variety of experimental procedures and disease states. Since the system is applicable to human bone-marrow cells, it should prove of value in the quantitative assay of (1) survival of human bone marrow on storage, and (2) bone-marrow content of granulocytic precursor cells in various disease states and following various types of therapy. The system is not suitable for the mass production in vitro of haemopoietic cells for therapeutic use. (author)

  9. Leisure, economy and colonial urbanism: Darjeeling, 1835–1930

    Science.gov (United States)

    BHATTACHARYA, NANDINI

    2013-01-01

    This article posits that the hill station of Darjeeling was a unique form of colonial urbanism. It shifts historiographical interest from major urban centres in colonial India (such as Bombay or Calcutta) and instead attempts a greater understanding of smaller urban centres. In the process, it also interrogates the category of hill stations, which have been understood as exotic and scenic sites rather than as towns that were integral to the colonial economy. In arguing that hill stations, particularly Darjeeling, were not merely the scenic and healthy ‘other’ of the clamorous, dirty and diseased plains of India, it refutes suggestions that the ‘despoiling’ or overcrowding of Darjeeling was incremental to the purposes of its establishment. Instead, it suggests that Darjeeling was part of the colonial mainstream; its urbanization and inclusion into the greater colonial economy was effected from the time of its establishment. Therefore, a constant tension between its exotic and its functional elements persisted throughout. PMID:24273391

  10. Leisure, economy and colonial urbanism: Darjeeling, 1835-1930.

    Science.gov (United States)

    Bhattacharya, Nandini

    2013-08-01

    This article posits that the hill station of Darjeeling was a unique form of colonial urbanism. It shifts historiographical interest from major urban centres in colonial India (such as Bombay or Calcutta) and instead attempts a greater understanding of smaller urban centres. In the process, it also interrogates the category of hill stations, which have been understood as exotic and scenic sites rather than as towns that were integral to the colonial economy. In arguing that hill stations, particularly Darjeeling, were not merely the scenic and healthy 'other' of the clamorous, dirty and diseased plains of India, it refutes suggestions that the 'despoiling' or overcrowding of Darjeeling was incremental to the purposes of its establishment. Instead, it suggests that Darjeeling was part of the colonial mainstream; its urbanization and inclusion into the greater colonial economy was effected from the time of its establishment. Therefore, a constant tension between its exotic and its functional elements persisted throughout.

  11. Honey Bee Colonies Remote Monitoring System

    Directory of Open Access Journals (Sweden)

    Sergio Gil-Lebrero

    2016-12-01

    Full Text Available Bees are very important for terrestrial ecosystems and, above all, for the subsistence of many crops, due to their ability to pollinate flowers. Currently, the honey bee populations are decreasing due to colony collapse disorder (CCD. The reasons for CCD are not fully known, and as a result, it is essential to obtain all possible information on the environmental conditions surrounding the beehives. On the other hand, it is important to carry out such information gathering as non-intrusively as possible to avoid modifying the bees’ work conditions and to obtain more reliable data. We designed a wireless-sensor networks meet these requirements. We designed a remote monitoring system (called WBee based on a hierarchical three-level model formed by the wireless node, a local data server, and a cloud data server. WBee is a low-cost, fully scalable, easily deployable system with regard to the number and types of sensors and the number of hives and their geographical distribution. WBee saves the data in each of the levels if there are failures in communication. In addition, the nodes include a backup battery, which allows for further data acquisition and storage in the event of a power outage. Unlike other systems that monitor a single point of a hive, the system we present monitors and stores the temperature and relative humidity of the beehive in three different spots. Additionally, the hive is continuously weighed on a weighing scale. Real-time weight measurement is an innovation in wireless beehive—monitoring systems. We designed an adaptation board to facilitate the connection of the sensors to the node. Through the Internet, researchers and beekeepers can access the cloud data server to find out the condition of their hives in real time.

  12. An improved method for staining cell colonies in clonogenic assays.

    Science.gov (United States)

    Guda, Kishore; Natale, Leanna; Markowitz, Sanford D

    2007-06-01

    Clonogenic assay is a widely used experimental approach to test for the effects of drugs/genes on the growth and proliferative characteristics of cells in vitro. Accurate quantitation of treatment effects in clonogeneic assays depends on the ability to visualize and count cell colonies precisely. We report a novel method (referred as ETeB) for staining cell colonies grown on plastic and specially coated substrates like collagen. Using colon cancer cell lines grown on plastic and collagen, we compared the colony staining efficiencies of the widely used methylene blue, and Ethidium bromide (ETeB) stains. Results show that the ETeB protocol works well on plastic and is extremely effective for staining colonies on collagen when compared to methylene blue. The key features and advantages of ETeB technique are; (a) reduction in background for colonies grown on collagen and possibly other substrates, (b) the whole procedure takes less than a minute, (c) no post-stain washing step is required which eliminates colony losses for cell lines that are loosely adherent, (d) colony visualization and counting can be done immediately following the staining procedure using a standard UV illuminator and software, and (e) the method works across a wide variety of cell lines. The simplicity and robustness of this procedure should warrant its usage in both small and large-scale clonogenic experiments.

  13. Trial of using antibodies as carriers of alkylating agents. Pt. 2. Evaluation of ability to form /sup 32/P-cyclophosphamide + immune antibody complexes with homologous antigen

    Energy Technology Data Exchange (ETDEWEB)

    Trzeciak, J; Felus, E; Nolewajka, E; Szaflarski, J; Dudziak, Z [Slaska Akademia Medyczna, Katowice (Poland)

    1976-01-01

    /sup 32/P-cyclophosphamide was found to combine with ..gamma..-globulin fractions of immune sera. Immune sera incubated with /sup 32/P-cyclophosphamide retained ability to react specifically with homologou antigen in vitro in the system: MN antigens of human erythrocytes + rabbit anti-MN antibody, and probably reacted selectively with target antigens in vivo in the system: antigens of guinea pig kidney tissue + rabbit antibodies against these antigens. Hemagglutination, passive hemagglutination and precipitation in agar gel tests were used in the experiments. Ability to combine of the immune antibody + /sup 32/P-cyclophosphamide complex with homologous antigens was evaluated by measurements of radioactivity of studied materials (erythrocyte agglutinates and organ homogenates). The results indicate feasibility of using immune antibodies as carriers of cytostatic agents.

  14. Mycological analysis of cereal samples and screening of Fusarium strains' ability to form deoxynivalenole (DON) and zearalenone (ZEA) mycotoxins--a pilot study.

    Science.gov (United States)

    Kłyszejko, Adriana; Kubus, Zaneta; Zakowska, Zofia

    2005-01-01

    Filamentous fungi are cosmopolitan microorganisms found in almost all environments. It should be pointed out that occurance of moulds on food or feed may cause health disorders in humans and animals. Mycoflora appears as a source of toxic methabolites, mycotoxins, which hepatotoxic, genotoxic, nefrotoxic and carcinogenic abilities were already proven in several studies. Hense mycological analysis of cereal grains raises as an important manner in evaluation of food and feed health features. Among the most frequent cereal contaminants Alternaria, Aspergillus, Fusarium and Penicillium strains are mentioned. Due to their ability to grow on cereals during both its field growth and storage, Fusarium moulds occure to be an important contamination factors in food and feed industry. In this study Fusarium strains isolates from wheat and maize were examined in order to recognize their abilities to produce two toxins: zearalenon (ZEA) and deoxynivalenole (DON). Mycological analysis shown differentiation within fungal microflora occuring in samples of different storage conditions, where Fusarium strains represented aproximately 20-70% of all mould species present. In purpose of Fusarium strains species evaluation, isolates were mycologically analysed. In the second step of the project, toxicological screening of isolates was performed using Thin Liquid Chromatography (TLC) evaluating toxigenic potential of single strains' production of ZEA and DON. This data gives the possibility of pointing the most toxigenic strains and also shows differentiations in their occurance in cereals. This paper presents introductory research data, which can be useful in recognition of cereal contamination with moulds and their toxic methabolites.

  15. Growth Mechanism of Microbial Colonies

    Science.gov (United States)

    Zhu, Minhui; Martini, K. Michael; Kim, Neil H.; Sherer, Nicholas; Lee, Jia Gloria; Kuhlman, Thomas; Goldenfeld, Nigel

    Experiments on nutrient-limited E. coli colonies, growing on agar gel from single cells reveal a power-law distribution of sizes, both during the growth process and in the final stage when growth has ceased. We developed a Python simulation to study the growth mechanism of the bacterial population and thus understand the broad details of the experimental findings. The simulation takes into account nutrient uptake, metabolic function, growth and cell division. Bacteria are modeled in two dimensions as hard circle-capped cylinders with steric interactions and elastic stress dependent growth characteristics. Nutrient is able to diffuse within and between the colonies. The mechanism of microbial colony growth involves reproduction of cells within the colonies and the merging of different colonies. We report results on the dynamic scaling laws and final state size distribution, that capture in semi-quantitative detail the trends observed in experiment. Supported by NSF Grant 0822613.

  16. Ant Larval Demand Reduces Aphid Colony Growth Rates in an Ant-Aphid Interaction

    Directory of Open Access Journals (Sweden)

    James M. Cook

    2012-02-01

    Full Text Available Ants often form mutualistic interactions with aphids, soliciting honeydew in return for protective services. Under certain circumstances, however, ants will prey upon aphids. In addition, in the presence of ants aphids may increase the quantity or quality of honeydew produced, which is costly. Through these mechanisms, ant attendance can reduce aphid colony growth rates. However, it is unknown whether demand from within the ant colony can affect the ant-aphid interaction. In a factorial experiment, we tested whether the presence of larvae in Lasius niger ant colonies affected the growth rate of Aphis fabae colonies. Other explanatory variables tested were the origin of ant colonies (two separate colonies were used and previous diet (sugar only or sugar and protein. We found that the presence of larvae in the ant colony significantly reduced the growth rate of aphid colonies. Previous diet and colony origin did not affect aphid colony growth rates. Our results suggest that ant colonies balance the flow of two separate resources from aphid colonies- renewable sugars or a protein-rich meal, depending on demand from ant larvae within the nest. Aphid payoffs from the ant-aphid interaction may change on a seasonal basis, as the demand from larvae within the ant colony waxes and wanes.

  17. Ant colony algorithm for clustering in portfolio optimization

    Science.gov (United States)

    Subekti, R.; Sari, E. R.; Kusumawati, R.

    2018-03-01

    This research aims to describe portfolio optimization using clustering methods with ant colony approach. Two stock portfolios of LQ45 Indonesia is proposed based on the cluster results obtained from ant colony optimization (ACO). The first portfolio consists of assets with ant colony displacement opportunities beyond the defined probability limits of the researcher, where the weight of each asset is determined by mean-variance method. The second portfolio consists of two assets with the assumption that each asset is a cluster formed from ACO. The first portfolio has a better performance compared to the second portfolio seen from the Sharpe index.

  18. The chemical digestion of Ti6Al7Nb scaffolds produced by Selective Laser Melting reduces significantly ability of Pseudomonas aeruginosa to form biofilm.

    Science.gov (United States)

    Junka, Adam F; Szymczyk, Patrycja; Secewicz, Anna; Pawlak, Andrzej; Smutnicka, Danuta; Ziółkowski, Grzegorz; Bartoszewicz, Marzenna; Chlebus, Edward

    2016-01-01

    In our previous work we reported the impact of hydrofluoric and nitric acid used for chemical polishing of Ti-6Al-7Nb scaffolds on decrease of the number of Staphylococcus aureus biofilm forming cells. Herein, we tested impact of the aforementioned substances on biofilm of Gram-negative microorganism, Pseudomonas aeruginosa, dangerous pathogen responsible for plethora of implant-related infections. The Ti-6Al-7Nb scaffolds were manufactured using Selective Laser Melting method. Scaffolds were subjected to chemical polishing using a mixture of nitric acid and fluoride or left intact (control group). Pseudomonal biofilm was allowed to form on scaffolds for 24 hours and was removed by mechanical vortex shaking. The number of pseudomonal cells was estimated by means of quantitative culture and Scanning Electron Microscopy. The presence of nitric acid and fluoride on scaffold surfaces was assessed by means of IR and rentgen spetorscopy. Quantitative data were analysed using the Mann-Whitney test (P ≤ 0.05). Our results indicate that application of chemical polishing correlates with significant drop of biofilm-forming pseudomonal cells on the manufactured Ti-6Al-7Nb scaffolds ( p = 0.0133, Mann-Whitney test) compared to the number of biofilm-forming cells on non-polished scaffolds. As X-ray photoelectron spectroscopy revealed the presence of fluoride and nitrogen on the surface of scaffold, we speculate that drop of biofilm forming cells may be caused by biofilm-supressing activity of these two elements.

  19. Inhibition of Blumeria graminis germination and germling development within colonies of oat mildew

    DEFF Research Database (Denmark)

    Carver, T.L.W.; Roberts, P.C.; Thomas, B.J.

    2001-01-01

    Germination by Blumeria graminis. DC Speer ff. spp. avenae, hordei and tritici, was greatly suppressed when conidia fell within colonies of ff. spp. avenae or hordei established on susceptible oat or barley, respectively. On healthy oat or barley, and when distant from powdery mildew, colonies. all...... ff. spp. formed normal appressoria. This was also true When conidia germinated within established barley mildew colonies. Within barley mildew colonies, appressoria of f. sp. hordei penetrated epidermal cells formed haustoria more frequently than appressoria distant from colonies. Similarly, ff. spp....... avenae and tritici, normally unable to infect barley. frequently penetrated epidermal cells subtending established barley mildew colonies. Thus, colony, establishment induced barley epidermal cell accessibility, even to non-pathogenic ff. spp, In contrast. when all three ff. spp. germinated within...

  20. Colony stimulating factors and their clinical implication

    International Nuclear Information System (INIS)

    Asano, Shigetaka

    1989-01-01

    Granulocytes and macrophage are dependent for their production and/or functional activation in vitro on the presence of a family of glycoproteins. They are generally called colony-stimulating factors (CSFs) because of their capacity to stimulate colony formation in semi-solid cultures, and are currently classified into four distinct subtypes, that is, Multi-CSF, GM-CSF, G-CSF and M-CSF, according to the cell type of colonies formed under their stimulation or their target cell specificity. All of the murine and human CSF subtypes and the genes for them have become available in a purified form and in a large scale, and now allow us to investigate their interactions, the mechanisms for their actions, the cell-cell interactions leading to their production and secretion, and their actions in vivo. Furthermore, the preclinical and/or clinical studies which were carried out using the purified CSFs strongly indicate that human CSFs will be effective strategies for preventing and treating opportunistic bacterial and fungal infection as a major cause of death in granulocytopenic patients. (author)

  1. JAX Colony Management System (JCMS): an extensible colony and phenotype data management system.

    Science.gov (United States)

    Donnelly, Chuck J; McFarland, Mike; Ames, Abigail; Sundberg, Beth; Springer, Dave; Blauth, Peter; Bult, Carol J

    2010-04-01

    The Jackson Laboratory Colony Management System (JCMS) is a software application for managing data and information related to research mouse colonies, associated biospecimens, and experimental protocols. JCMS runs directly on computers that run one of the PC Windows operating systems, but can be accessed via web browser interfaces from any computer running a Windows, Macintosh, or Linux operating system. JCMS can be configured for a single user or multiple users in small- to medium-size work groups. The target audience for JCMS includes laboratory technicians, animal colony managers, and principal investigators. The application provides operational support for colony management and experimental workflows, sample and data tracking through transaction-based data entry forms, and date-driven work reports. Flexible query forms allow researchers to retrieve database records based on user-defined criteria. Recent advances in handheld computers with integrated barcode readers, middleware technologies, web browsers, and wireless networks add to the utility of JCMS by allowing real-time access to the database from any networked computer.

  2. Genetic diversity affects colony survivorship in commercial honey bee colonies

    Science.gov (United States)

    Tarpy, David R.; vanEngelsdorp, Dennis; Pettis, Jeffrey S.

    2013-08-01

    Honey bee ( Apis mellifera) queens mate with unusually high numbers of males (average of approximately 12 drones), although there is much variation among queens. One main consequence of such extreme polyandry is an increased diversity of worker genotypes within a colony, which has been shown empirically to confer significant adaptive advantages that result in higher colony productivity and survival. Moreover, honey bees are the primary insect pollinators used in modern commercial production agriculture, and their populations have been in decline worldwide. Here, we compare the mating frequencies of queens, and therefore, intracolony genetic diversity, in three commercial beekeeping operations to determine how they correlate with various measures of colony health and productivity, particularly the likelihood of queen supersedure and colony survival in functional, intensively managed beehives. We found the average effective paternity frequency ( m e ) of this population of honey bee queens to be 13.6 ± 6.76, which was not significantly different between colonies that superseded their queen and those that did not. However, colonies that were less genetically diverse (headed by queens with m e ≤ 7.0) were 2.86 times more likely to die by the end of the study when compared to colonies that were more genetically diverse (headed by queens with m e > 7.0). The stark contrast in colony survival based on increased genetic diversity suggests that there are important tangible benefits of increased queen mating number in managed honey bees, although the exact mechanism(s) that govern these benefits have not been fully elucidated.

  3. Maintenance and methods of forming theoretical knowledge and methodical and practical abilities in area of physical culture for students, future specialists on social work

    Directory of Open Access Journals (Sweden)

    Leyfa A.V.

    2009-12-01

    Full Text Available The value of theoretical knowledge, methodical, practical studies, skills in forming physical activity of students is rotined. The level of mastering of components of physical activity is closely associate with the basic blocks of professional preparation of students and their future professional activity. Theoretical knowledge on discipline the «Physical culture» assist the certain affecting depth and breadth of mastering of knowledge of professional preparation.

  4. Globalization in the post - colonial world

    Directory of Open Access Journals (Sweden)

    Korobeynikova Larisa A.

    2016-01-01

    Full Text Available The paper presents a new interpretation of globalization within the boundaries of the author’s concept of soft globalization, which exploits a normatively attractive alternative to the concept of the Empire. It is argued here that the conditions of development of contemporary post - colonial world communities do not require any unification in the form of the Empire, but instead the creation of a non repressive mechanism of social regulation - the implementation of a form of soft globalization, a globalization with a mental form are expedient here. Historically, globalization occurred in a strict material(i.e. economical and military form that prompted the conditions for the evolution of civilization as the Empire: a case in which the development of the world occurs under the power of a single dominating state. Imperialistic politics leads to colonial politics formation. The history of the phenomena of civilization shows many instances of Empire globalization. Globalization in the Empire form was already observed at the time of the Roman Empire. At this time processes of development inside the Empire were manifestations of globalization in its highest cultural shape. But ancient Rome was also a social and political experiment that acquired the attributes of a purely material globalization in the end, and historically brought about the irreversible crash of the Roman Empire itself. Contemporary fluctuations referring to the process of globalization can be registered in the US’s attempts of material domination inside this or that existing case of civilization, which causes colonialism appearance. The main idea stressed in the paper is that only a mental globalization could succeed in the end.

  5. The Future Lunar Flora Colony

    Science.gov (United States)

    Goel, E. G.; Guven, U. G.

    2017-10-01

    A constructional design for the primary establishment for a lunar colony using the micrometeorite rich soil is proposed. It highlights the potential of lunar regolith combined with Earth technology for water and oxygen for human outposts on the Moon.

  6. Ability of bacterial biphenyl dioxygenases from Burkholderia sp. LB400 and Comamonas testosteroni B-356 to catalyse oxygenation of ortho-hydroxychlorobiphenyls formed from PCBs by plants

    International Nuclear Information System (INIS)

    Francova, K.; Mackova, M.; Macek, T.; Sylvestre, M.

    2004-01-01

    Bacterial dioxygenases are useful in breakdown of PCB products associated with plants. - Capacity of enzymes of the biphenyl/chlorobiphenyl pathway, especially biphenyl dioxygenase (BPDO) of two polychlorinated biphenyls (PCB) degrading bacteria, Burkholderia sp. LB400 and Comamonas testosteroni B-356, to metabolize ortho-substituted hydroxybiphenyls was tested.,These compounds found among plant products of PCB metabolism, are carrying chlorine atoms on the hydroxyl-substituted ring. The abilities of His-tagged purified LB400 and B-356 BPDOs to catalyze the oxygenation of 2-hydroxy-3-chlorobiphenyl, 2-hydroxy-5-chlorobiphenyl and 2-hydroxy-3,5-dichlorobiphenyl were compared. Both enzyme preparations catalyzed the hydroxylation of the three chloro-hydroxybiphenyls on the non-substituted ring. Neither LB400 BPDO nor B-356 BPDO oxygenated the substituted ring of the ortho-hydroxylated biphenyl. The fact that metabolites generated by both enzymes were identical for all three hydroxychlorobiphenyls tested; exclude any other mode of attack of these compounds by LB400 BPDOs than the ortho-meta oxygenation

  7. The ability of S.aureus to form biofilm on the Ti-6Al-7Nb scaffolds produced by Selective Laser Melting and subjected to the different types of surface modifications.

    Science.gov (United States)

    Szymczyk, Patrycja; Junka, Adam; Ziółkowski, Grzegorz; Smutnicka, Danuta; Bartoszewicz, Marzenna; Chlebus, Edward

    2013-01-01

    The Gram-positive coccus, Staphylococcus aureus, is the leading etiologic agent of limb and life-threatening biofilm-related infections in the patients following the orthopaedic implantations. The aim of the present paper is to estimate the ability of S. aureus to form biofilm on titanium alloy (Ti-6Al-7Nb) scaffolds produced by Selective Laser Melting (SLM) and subjected to the different types of surface modifications, including ultrasonic cleaning and chemical polishing. The results obtained indicate significantly the decreased ability of S.aureus to form biofilm on the surface of scaffolds subjected to the chemical polishing in comparison to the scaffolds cleaned ultrasonically. The data provided can be useful for future applications of the SLM technology in production of Ti-6Al-7Nb medical implants.

  8. Differential Ability of Maize and Soybean to Acquire and Utilize Phosphorus from Sparingly Soluble Forms in Low- and Medium-P Soils Using {sup 32}P

    Energy Technology Data Exchange (ETDEWEB)

    Adu-Gyamfi, J. J.; Aigner, M.; Linic, S. [Soil and Water Management and Crop Nutrition Laboratory, Seibersdorf (Austria); Gludovacz, D. [Nuclear Material Laboratory, Safeguard Analytical Services, International Atomic Energy Agency, Seibersdorf (Austria)

    2013-11-15

    A glasshouse pot experiment was conducted to evaluate the differential ability of maize (Zea mays) and soybean (Glycine max) to utilize soil phosphorus (P) for plant growth from total-P, available-P and inorganic (Ca-P, Al-P and Fe-P) soil P pools using a carrier-free {sup 32}P solution. A maize variety (DK 315) and a soybean variety (TGX 1910-4F) were grown in pots containing 1 kg of a low available P soil (Hungarian) or a medium available P (Waldviertel) soil labelled with {sup 32}P for 42 days or without {sup 32}P (unlabelled) for 42 and 60 days. The shoot and root biomass of maize and soybean were significantly greater when grown on the Waldviertel than on the Hungarian soils. The shoot P concentrations were higher for soybean (1.7-2.2 g kg{sup -1}) than for maize (1.1-1.4 g kg{sup -1}). The total radioactivity (dpm x 10{sup 6}) was higher in plants grown in Waldviertel than in Hungarian soil and the values reflected plant P uptake and shoot biomass of soybean and maize. The L-values ({mu}g P g soil{sup -1}) of maize and soybean were higher in Waldviertel (72-78) than in Hungarian (9.6-20) soil. No significant differences in L-values were observed for maize and soybean grown on the Waldviertel soil, but for the Hungarian soil, the L-values were higher for maize (20.0) than for soybean (9.6) suggesting that in this low-P soil, maize was more efficient than soybean in taking up soil P. The available P (Bray II) and the Ca-P were the fractions most depleted by plants followed by the Fe-P fractions in the two soils, but differences between the crops were not significant. When soil P is limited, maize and soybean are able to access P mainly from the available P (Bray II), Fe- and Ca-P sparingly soluble fractions and not Al-P from the soil. (author)

  9. Colonial and Communist Pedagogy

    Science.gov (United States)

    Leslie, Esther

    2016-01-01

    Walter Benjamin wrote about pedagogy from the start of his writing life to its close. He was also an activist in the youth movement in Germany. This essay explores the importance of childhood, play, toys and education to his wider body of work--including his interests in photography, literary form, language acquisition and use, modern art. The…

  10. Mamary neoplasia in a closed beagle colony

    International Nuclear Information System (INIS)

    Taylor, G.N.; Shabestari, L.; Williams, J.; Mays, C.W.; Angus, W.; McFarland, S.

    1975-01-01

    The incidence rate of mammary neoplasia in a large colony of beagles and its relationship to internal skeletal and/or liver radiation, age, relatively late ovariectomy (4 years and older), endometritis, parity status, and adrenal weight was examined. Of these various factors, age was the only condition that was clearly correlated with changes in the mammary tumor incidence. The rate became significant at approximately eight years of age and increased progressively throughout the successively older age classes. Within the female dogs, the incidence of mammary cancer was higher that that of any other form of spontaneous malignancy

  11. Structural organisation and dynamics in king penguin colonies

    Science.gov (United States)

    Gerum, Richard; Richter, Sebastian; Fabry, Ben; Le Bohec, Céline; Bonadonna, Francesco; Nesterova, Anna; Zitterbart, Daniel P.

    2018-04-01

    During breeding, king penguins do not build nests, however they show strong territorial behaviour and keep a pecking distance to neighbouring penguins. Penguin positions in breeding colonies are highly stable over weeks and appear regularly spaced, but thus far no quantitative analysis of the structural order inside a colony has been performed. In this study, we use the radial distribution function to analyse the spatial coordinates of penguin positions. Coordinates are obtained from aerial images of two colonies that were observed for several years. Our data demonstrate that the structural order in king penguin colonies resembles a 2D liquid of particles with a Lennard-Jones-type interaction potential. We verify this using a molecular dynamics simulation with thermally driven particles, whereby temperature corresponds to penguin movements, the energy well depth ɛ of the attractive potential corresponds to the strength of the colony-forming behaviour, and the repulsive zone corresponds to the pecking radius. We can recapitulate the liquid disorder of the colony, as measured by the radial distribution function, when the particles have a temperature of several (1.4–10) \

  12. Colonial army recruitment patterns and post-colonial Military Coups ...

    African Journals Online (AJOL)

    Since time immemorial, societies, states and state builders have been challenged and transformed by the need and quest for military manpower. European states relied on conscript armies to 'pacify' and retain colonies in parts of the non-European world. These facts underscore the meticulous attention paid by the British to ...

  13. Colonial Bilingual Heritage and Post-Colonial Myths in Cameroon's ...

    African Journals Online (AJOL)

    Thus, the study traces and shows that an uncritical support of the existing school bilingualism, a aspect of the general political objective of national unity and integration, hinges on a fictitious collective post-colonial dream about using the bilingual heritage of French and English, and the cultures that lie behind them, ...

  14. CULTURAL NATIONALISM IN A COLONIAL CONTEXT: LAOS IN FRENCH INDOCHINA, 1893-1940

    DEFF Research Database (Denmark)

    Ivarsson, Søren

    2008-01-01

    In general, studies dealing with the link between French colonialism and nationalism in Laos have focused on the anti-colonial or revolutionary aspects of Lao nationalism. This is true for texts written by Western scholars as well as officially sanctioned books on Lao history published in Laos. T....... This chapter approaches Lao nationalism from a cultural perspective, through a discussion of how a specific idea about Laos and its culture was formed under French colonial rule in the period 1893-1940....

  15. Legislative Redress Rather Than Progress? From Slavery to Bondage in Colonial India

    OpenAIRE

    Tetzlaff, Stefan

    2008-01-01

    Contemporary historiography on colonial rule in India is partly inclined to discuss changes and intensifications of numerous social phenomena as consequence of direct or indirect British intervention. According to their intellectual frameworks, authors emphasize different forms of intervention ranging from colonial policy making (for economical reasons) to conscious “social engineering” and action as a result of cultural misunderstanding. For the case of slavery in colonial India, Gyan Prakas...

  16. Effect of zirconium purity on the glass-forming-ability and notch toughness of Cu{sub 43}Zr{sub 43}Al{sub 7}Be{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, Laura M. [Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA (United States); Hofmann, Douglas C. [Materials Development and Manufacturing Technology Group, NASA Jet Propulsion Laboratory/California Institute of Technology, MS 18-105, 4800 Oak Grove Dr. Pasadena, CA 91109 (United States); Vecchio, Kenneth S., E-mail: kvecchio@ucsd.edu [Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA (United States)

    2016-09-30

    The effect of substituting standard grade zirconium lump (99.8% excluding up to 4% hafnium) for high purity zirconium crystal bar (99.5%) in a Cu{sub 43}Zr{sub 43}Al{sub 7}Be{sub 7} bulk metallic glass (BMG) is examined. The final hafnium content in the BMG specimens was found to range from 0 to 0.44 at%. Introducing low purity zirconium significantly decreased the glass-forming-ability and reduced the notch toughness of the BMG. In contrast, when adding high purity hafnium to Cu{sub 43}Zr{sub 43}Al{sub 7}Be{sub 7} made with high purity zirconium, no significant change in the glass-forming-ability or toughness was observed. This suggests that the introduction of low purity zirconium in BMGs creates a more complex response than a simple addition of hafnium. It is likely that other impurities in the material, such as oxygen, play a role in the complex crystallization kinetics and change in mechanical properties. The notch toughness was measured through four-point-bend tests, which showed a decrease in notch toughness from an average of ~53 MPa m{sup 1/2} for the high purity samples to an average of ~29 MPa m{sup 1/2} with full substitution of low purity zirconium. A similar decrease in glass-forming-ability and toughness is observed in commercially synthesized high purity Cu{sub 43}Zr{sub 43}Al{sub 7}Be{sub 7}. The large scale commercial process is expected to introduced some unintentional impurities, which decrease the properties of the BMG in the same way as the lower purity elements. Lastly, Weibull statistics are used to provide an analysis of variability in toughness for both ingots synthesized in a small laboratory arc-melter and those synthesized commercially.

  17. Chromoproteinoids and their ability to form boundary

    International Nuclear Information System (INIS)

    Heinz, B.

    1992-01-01

    Model systems for boundary structures and cellular systems, particularly when they are a result of natural simulation experiments, are always valuable for the study of the ''Origins of Life''. Lyophilization of chromoproteinoids - peptide like molecules containing prosthetic groups - leads to the formation of boundary structures

  18. Dutch Colonial Nostalgia Across Decolonisation

    NARCIS (Netherlands)

    Bijl, P.

    2013-01-01

    This article argues that nostalgia for colonialism in the Netherlands, the so called tempo doeloe culture, is not a specifically postcolonial phenomenon caused by the collapse of the Dutch empire in Asia. In fact, nostalgia for the Dutch East Indies can be traced back to the nineteenth century, when

  19. Colonial adventures in tropical agriculture

    NARCIS (Netherlands)

    Buelens, Frans; Frankema, Ewout

    2016-01-01

    How profitable were foreign investments in plantation agriculture in the Netherlands Indies during the late colonial era? We use a new dataset of monthly quoted stock prices and dividends of international companies at the Brussels stock exchange to estimate the returns to investment in tropical

  20. Affective Politics and Colonial Heritage

    DEFF Research Database (Denmark)

    Knudsen, Britta Timm; Andersen, Casper

    2017-01-01

    The article analyses the spatial entanglement of colonial heritage struggles through a study of the Rhodes Must Fall student movement at the University of Cape Town and the University of Oxford. We explore affective politics and the role heritage can play in the landscape of body politics. We aim...

  1. Ant Colony Optimization for Control

    NARCIS (Netherlands)

    Van Ast, J.M.

    2010-01-01

    The very basis of this thesis is the collective behavior of ants in colonies. Ants are an excellent example of how rather simple behavior on a local level can lead to complex behavior on a global level that is beneficial for the individuals. The key in the self-organization of ants is communication

  2. Transformaciones y formas de legitimación en la autoridad de los caciques coloniales de Jujuy: Siglo XVII Transformations and forms of legitimacy within colonial caciques authority: Province of Jujuy, 17th century

    Directory of Open Access Journals (Sweden)

    Gabriela Sica

    2009-06-01

    Full Text Available Este trabajo intenta analizar las transformaciones de la autoridad en los jefes étnicos en la jurisdicción de la ciudad de San Salvador de Jujuy (Gobernación del Tucumán durante el siglo XVII. Parte de estas transformaciones estaban condicionadas por la concesión de encomiendas y la creación de los pueblos de indios y nuevas instituciones, como los cabildos indígenas. Estas circunstancias limitaron el poder de las antiguas autoridades, sin embargo a lo largo del siglo XVII surgieron nuevos cargos como el de cacique gobernador y nuevas formas de legitimación que intentaban contrarrestar estos cambios.This paper attempts to analyze some changes within the ethnic leaders' authority in the jurisdiction of San Salvador de Jujuy city ( Gobernación del Tucumán during the seventeenth century. Some of these changes were influenced by the granting of encomiendas and the creation of Indians towns and new institutions such as Indian cabildos. These circumstances limited the power of ancient authorities, however during the seventeenth century new offices, such as the cacique de Gobernador, and new forms of legitimacy emerged in order to counterbalance the above-mentioned changes.

  3. Changes in learning and foraging behaviour within developing bumble bee (Bombus terrestris colonies.

    Directory of Open Access Journals (Sweden)

    Lisa J Evans

    Full Text Available Organisation in eusocial insect colonies emerges from the decisions and actions of its individual members. In turn, these decisions and actions are influenced by the individual's behaviour (or temperament. Although there is variation in the behaviour of individuals within a colony, we know surprisingly little about how (or indeed if the types of behaviour present in a colony change over time. Here, for the first time, we assessed potential changes in the behavioural type of foragers during colony development. Using an ecologically relevant foraging task, we measured the decision speed and learning ability of bumble bees (Bombus terrestris at different stages of colony development. We determined whether individuals that forage early in the colony life cycle (the queen and early emerging workers behaved differently from workers that emerge and forage at the end of colony development. Whilst we found no overall change in the foraging behaviour of workers with colony development, there were strong differences in foraging behaviour between queens and their workers. Queens appeared to forage more cautiously than their workers and were also quicker to learn. These behaviours could allow queens to maximise their nectar collecting efficiency whilst avoiding predation. Because the foundress queen is crucial to the survival and success of a bumble bee colony, more efficient foraging behaviour in queens may have strong adaptive value.

  4. Art Education in Colonial India: Implementation and Imposition

    Science.gov (United States)

    Kantawala, Ami

    2012-01-01

    Historical inquiry in art education forms the basis of any research undertaken in the field. It is on this path that we discover ignored moments and personalities and clarify challenging ideas, thus approaching history from multiple perspectives. This historical study attempts to reframe the past of colonial Indian art education within the broader…

  5. Queen promiscuity lowers disease within honeybee colonies

    Science.gov (United States)

    Seeley, Thomas D; Tarpy, David R

    2006-01-01

    Most species of social insects have singly mated queens, but in some species each queen mates with numerous males to create a colony with a genetically diverse worker force. The adaptive significance of polyandry by social insect queens remains an evolutionary puzzle. Using the honeybee (Apis mellifera), we tested the hypothesis that polyandry improves a colony's resistance to disease. We established colonies headed by queens that had been artificially inseminated by either one or 10 drones. Later, we inoculated these colonies with spores of Paenibacillus larvae, the bacterium that causes a highly virulent disease of honeybee larvae (American foulbrood). We found that, on average, colonies headed by multiple-drone inseminated queens had markedly lower disease intensity and higher colony strength at the end of the summer relative to colonies headed by single-drone inseminated queens. These findings support the hypothesis that polyandry by social insect queens is an adaptation to counter disease within their colonies. PMID:17015336

  6. 75 FR 28685 - Colonial Bankshares, MHC, Vineland, NJ; Approval of Conversion Application

    Science.gov (United States)

    2010-05-21

    ... DEPARTMENT OF THE TREASURY Office of Thrift Supervision [AC-41: OTS Nos. 04983, H-3879, and H-4714... May 14, 2010, the Office of Thrift Supervision approved the application of Colonial Bankshares, MHC, and Colonial Bank, Vineland, New Jersey, to convert to the stock form of organization. Copies of the...

  7. Impaired T-lymphocyte colony formation by cord blood mononuclear cells

    International Nuclear Information System (INIS)

    Herrod, H.G.; Valenski, W.R.

    1982-01-01

    When compared to adult mononuclear cells, cord blood mononuclear cells demonstrated significantly decreased T-lymphocyte colony formation (1351 +/- 643 vs 592 +/- 862, P less than 0.01). This diminished colony-forming activity did not appear to be associated with impaired responsiveness to the stimulant phytohemagglutinin or with excessive suppressor-cell activity. Irradiation reduced the colony-forming capacity of cord blood mononuclear cells more than it did that of adult mononuclear cells. Depletion of adherent cells reduced cord blood mononuclear-cell colony-forming capacity by 40%, while similar treatment reduced adult colony formation by 10%. Lymphocyte proliferation in liquid culture of cord and adult cells was minimally affected by these procedures. The colony-forming capacity of cord blood could be enhanced by the addition of irradiated adult cells (284 +/- 72 vs 752 +/- 78, P less than 0.01). This enhancement was demonstrated to be due to a soluble factor produced by a population of irradiated adult cells depleted of the OKT8+ subpopulation of lymphocytes. These results indicate that the progenitor cells of T-lymphocyte colonies in cord blood have distinct biologic characteristics when compared to colony progenitors present in adult blood. This assay may prove to be useful in our efforts to understand the differentiation of T-cell function in man

  8. Indigenous education during the pre-colonial period in Southern Africa

    African Journals Online (AJOL)

    ... process was intimately integrated with the social, cultural, artistic, religious and recreational life of the indigenous peoples. This article discusses different forms of indigenous education that existed in Southern Africa during the pre-colonial period. Keywords: Pre-colonial period, indigenous education, indigenous people,

  9. Microbiome of Trichodesmium Colonies from the North Pacific Subtropical Gyre

    Directory of Open Access Journals (Sweden)

    Mary R. Gradoville

    2017-07-01

    Full Text Available Filamentous diazotrophic Cyanobacteria of the genus Trichodesmium, often found in colonial form, provide an important source of new nitrogen to tropical and subtropical marine ecosystems. Colonies are composed of several clades of Trichodesmium in association with a diverse community of bacterial and eukaryotic epibionts. We used high-throughput 16S rRNA and nifH gene sequencing, carbon (C and dinitrogen (N2 fixation assays, and metagenomics to describe the diversity and functional potential of the microbiome associated with Trichodesmium colonies collected from the North Pacific Subtropical Gyre (NPSG. The 16S rRNA and nifH gene sequences from hand-picked colonies were predominantly (>99% from Trichodesmium Clade I (i.e., T. thiebautii, which is phylogenetically and ecologically distinct from the Clade III IMS101 isolate used in most laboratory studies. The bacterial epibiont communities were dominated by Bacteroidetes, Alphaproteobacteria, and Gammaproteobacteria, including several taxa with a known preference for surface attachment, and were relatively depleted in the unicellular Cyanobacteria and small photoheterotrophic bacteria that dominate NPSG surface waters. Sequencing the nifH gene (encoding a subcomponent of the nitrogenase enzyme identified non-Trichodesmium diazotrophs that clustered predominantly among the Cluster III nifH sequence-types that includes putative anaerobic diazotrophs. Trichodesmium colonies may represent an important habitat for these Cluster III diazotrophs, which were relatively rare in the surrounding seawater. Sequence analyses of nifH gene transcripts revealed several cyanobacterial groups, including heterocystous Richelia, associated with the colonies. Both the 16S rRNA and nifH datasets indicated strong differences between Trichodesmium epibionts and picoplankton in the surrounding seawater, and also between the epibionts inhabiting Trichodesmium puff and tuft colony morphologies. Metagenomic and 16S r

  10. Recent Honey Bee Colony Declines

    Science.gov (United States)

    2007-06-20

    podcasts.psu.edu/taxonomy/term/62]. Staple crops such as wheat , corn, and rice do not rely on insect pollination and are mostly wind pollinated...are interacting to weaken bee colonies and are allowing stress-related pathogens, such as fungi , thus causing a final collapse.27 Others note the...possible role of miticide resistance in bees. High levels of bacteria, viruses, and fungi have been found in the guts of the recoverable dead bees

  11. A Burkholderia pseudomallei colony variant necessary for gastric colonization.

    Science.gov (United States)

    Austin, C R; Goodyear, A W; Bartek, I L; Stewart, A; Sutherland, M D; Silva, E B; Zweifel, A; Vitko, N P; Tuanyok, A; Highnam, G; Mittelman, D; Keim, P; Schweizer, H P; Vázquez-Torres, A; Dow, S W C; Voskuil, M I

    2015-02-03

    Diverse colony morphologies are a hallmark of Burkholderia pseudomallei recovered from infected patients. We observed that stresses that inhibit aerobic respiration shifted populations of B. pseudomallei from the canonical white colony morphotype toward two distinct, reversible, yet relatively stable yellow colony variants (YA and YB). As accumulating evidence supports the importance of B. pseudomallei enteric infection and gastric colonization, we tested the response of yellow variants to hypoxia, acidity, and stomach colonization. Yellow variants exhibited a competitive advantage under hypoxic and acidic conditions and alkalized culture media. The YB variant, although highly attenuated in acute virulence, was the only form capable of colonization and persistence in the murine stomach. The accumulation of extracellular DNA (eDNA) was a characteristic of YB as observed by 4',6-diamidino-2-phenylindole (DAPI) staining of gastric tissues, as well as in an in vitro stomach model where large amounts of eDNA were produced without cell lysis. Transposon mutagenesis identified a transcriptional regulator (BPSL1887, designated YelR) that when overexpressed produced the yellow phenotype. Deletion of yelR blocked a shift from white to the yellow forms. These data demonstrate that YB is a unique B. pseudomallei pathovariant controlled by YelR that is specifically adapted to the harsh gastric environment and necessary for persistent stomach colonization. Seemingly uniform populations of bacteria often contain subpopulations that are genetically identical but display unique characteristics which offer advantages when the population is faced with infrequent but predictable stresses. The pathogen Burkholderia pseudomallei is capable of forming several reversible colony types, and it interconverted between one white type and two yellow types under certain environmental stresses. The two yellow forms exhibited distinct advantages in low-oxygen and acidic environments. One yellow

  12. Beyond packing of hard spheres: The effects of core softness, non-additivity, intermediate-range repulsion, and many-body interactions on the glass-forming ability of bulk metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Kai; Fan, Meng; Liu, Yanhui; Schroers, Jan [Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520 (United States); Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520 (United States); Shattuck, Mark D. [Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520 (United States); Department of Physics and Benjamin Levich Institute, The City College of the City University of New York, New York, New York 10031 (United States); O’Hern, Corey S. [Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520 (United States); Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520 (United States); Department of Physics, Yale University, New Haven, Connecticut 06520 (United States); Department of Applied Physics, Yale University, New Haven, Connecticut 06520 (United States)

    2015-11-14

    When a liquid is cooled well below its melting temperature at a rate that exceeds the critical cooling rate R{sub c}, the crystalline state is bypassed and a metastable, amorphous glassy state forms instead. R{sub c} (or the corresponding critical casting thickness d{sub c}) characterizes the glass-forming ability (GFA) of each material. While silica is an excellent glass-former with small R{sub c} < 10{sup −2} K/s, pure metals and most alloys are typically poor glass-formers with large R{sub c} > 10{sup 10} K/s. Only in the past thirty years have bulk metallic glasses (BMGs) been identified with R{sub c} approaching that for silica. Recent simulations have shown that simple, hard-sphere models are able to identify the atomic size ratio and number fraction regime where BMGs exist with critical cooling rates more than 13 orders of magnitude smaller than those for pure metals. However, there are a number of other features of interatomic potentials beyond hard-core interactions. How do these other features affect the glass-forming ability of BMGs? In this manuscript, we perform molecular dynamics simulations to determine how variations in the softness and non-additivity of the repulsive core and form of the interatomic pair potential at intermediate distances affect the GFA of binary alloys. These variations in the interatomic pair potential allow us to introduce geometric frustration and change the crystal phases that compete with glass formation. We also investigate the effect of tuning the strength of the many-body interactions from zero to the full embedded atom model on the GFA for pure metals. We then employ the full embedded atom model for binary BMGs and show that hard-core interactions play the dominant role in setting the GFA of alloys, while other features of the interatomic potential only change the GFA by one to two orders of magnitude. Despite their perturbative effect, understanding the detailed form of the intermetallic potential is important for

  13. Honeybee immunity and colony losses

    Directory of Open Access Journals (Sweden)

    F. Nazzi

    2014-10-01

    Full Text Available The decline of honeybee colonies and their eventual collapse is a widespread phenomenon in the Northern hemisphere of the globe, which severely limits the beekeeping industry. This dramatic event is associated with an enhanced impact of parasites and pathogens on honeybees, which is indicative of reduced immunocompetence. The parasitic mite Varroa destructor and the vectored viral pathogens appear to play a key-role in the induction of this complex syndrome. In particular, the Deformed Wing Virus (DWV is widespread and is now considered, along with Varroa, one of the major causes of bee colony losses. Several lines of evidence indicate that this mite/DWV association severely affects the immune system of honeybees and makes them more sensitive to the action of other stress factors. The molecular mechanisms underpinning these complex interactions are currently being investigated and the emerging information has allowed the development of a new functional model, describing how different stress factors may synergistically concur in the induction of bee immune alteration and health decline. This provides a new logical framework in which to interpret the proposed multifactorial origin of bee colony losses and sets the stage for a more comprehensive and integrated analysis of the effect that multiple stress agents may have on honeybees.

  14. Thermally adapted design strategy of colonial houses in Surabaya

    Science.gov (United States)

    Antaryama, I. G. N.; Ekasiwi, S. N. N.; Mappajaya, A.; Ulum, M. S.

    2018-03-01

    Colonial buildings, including houses, have been considered as a representation of climate-responsive architecture. The design was thought to be a hybrid model of Dutch and tropical architecture. It was created by way of reinventing tropical and Dutch architecture design principles, and expressed in a new form, i.e. neither resembling Dutch nor tropical building. Aside from this new image, colonial house does show good climatic responses. Previous researches on colonial house generally focus on qualitative assessment of climate performance of the building. Yet this kind of study tends to concentrate on building elements, e.g. wall, window, etc. The present study is designed to give more complete picture of architecture design strategy of the house by exploring and analysing thermal performance of colonial buildings and their related architecture design strategies. Field measurements are conducted during the dry season in several colonial building in Surabaya. Air temperature and humidity are both taken, representing internal and external thermal conditions of the building. These data are then evaluated to determine thermal performance of the house. Finally, various design strategies are examined in order to reveal their significant contributions to its thermal performance. Results of the study in Surabaya confirm findings of the previous researches that are conducted in other locations, which stated that thermal performance of the house is generally good. Passive design strategies such as mass effect and ventilation play an important role in determining performance of the building.

  15. Creating Central Sulawesi. Mission Intervention, Colonialism and ‘Multiculturality’

    Directory of Open Access Journals (Sweden)

    J. Coté

    2011-01-01

    Full Text Available Creating Central Sulawesi: Mission Intervention, Colonialism and ‘Multiculturality’Central Sulawesi provides an example of how, under colonialism, non-state bodies contributed to the creation of new political identities in the Indonesian archipelago, and how the modern Indonesian state came to be based on these. Arguably, at the beginning of the twentieth century, the region was poised to be incorporated into the structure of one or other of the existing powerful Central and Southern Sulawesi political entities. As such, as just another ‘region’ in the sprawling archipelagic colony subjected to standard colonial policy, it should have been readily incorporated into the Indonesian state, albeit through the ‘Sulawesi Permesta’. Instead, in seeking to establish what one writer has described as a ‘volkskerk’ [people’s church], the ‘Poso mission’ established with colonial support by the Nederlandsche Zendinggenootschap [Netherlands Missionary Society] in 1892, was instrumental in defining new religious, cultural and linguistic boundaries. These acted to effectively isolate the Pamona people from adjacent Christian communities established by other missionary endeavours; from their Islamic neighbours and, arguably, from the ‘nation’. As elsewhere in the archipelago, the subsequent process of this region’s reintegration has formed part of the difficult postcolonial legacy inherited by the Indonesian nation.

  16. Formation of large colonies: a defense mechanism of Microcystis aeruginosa under continuous grazing pressure by flagellate Ochromonas sp.

    Directory of Open Access Journals (Sweden)

    Fanxiang Kong

    2012-01-01

    Full Text Available Induced colony formation under grazing pressure has been reported in our previous results. However, the colonies induced in these studies comprised only tens of cells which are far smaller than the naturally occurring colonies. In this work, unicellular Microcystis aeruginosa Kützing were co-cultivated with flagellate Ochromonas sp. for 50 d to investigate colony formation in M. aeruginosa under continuous grazing pressure. Results revealed that colonial M. aeruginosa formed on the 10th d under the grazing pressure of flagellate. These algal colonies resulted from the daughter cells of freshly dividing cells that failed to separate during the reproductive process. The diameters and cell numbers of the colonies increased slowly with time. Under continuous grazing pressure by Ochromonas sp. for 50 d, the diameter of some colonies reached over 180 μm. Analysis showed that the extracellular polysaccharide (EPS content and relative gas vesicle (RGV of each cell increased significantly after colony formation. However, there was no significant difference on the monosaccharide composition between unicellular and colonial M. aeruginosa. The loose aggregation of cells in the floating colonies suggests that a correlation probably exists between cell compactness and colony buoyancy.

  17. Early Functional Abilities

    DEFF Research Database (Denmark)

    Lorentzen, Jakob; Poulsen, Ingrid

    2005-01-01

    Early Functional Abilities (EFA), - en skala til evaluering af behandlingsforløb af svært hjerneskadede patienter i forbindelse med tidlig rehabilitering. Formål At monitorere og dokumentere rehabiliteringsforløbet for svært hjerneskadede patienter, hvor funktionsniveauet endnu ikke kan registreres...

  18. Study of budding yeast colony formation and its characterizations by using circular granular cell

    Science.gov (United States)

    Aprianti, D.; Haryanto, F.; Purqon, A.; Khotimah, S. N.; Viridi, S.

    2016-03-01

    Budding yeast can exhibit colony formation in solid substrate. The colony of pathogenic budding yeast can colonize various surfaces of the human body and medical devices. Furthermore, it can form biofilm that resists drug effective therapy. The formation of the colony is affected by the interaction between cells and with its growth media. The cell budding pattern holds an important role in colony expansion. To study this colony growth, the molecular dynamic method was chosen to simulate the interaction between budding yeast cells. Every cell was modelled by circular granular cells, which can grow and produce buds. Cohesion force, contact force, and Stokes force govern this model to mimic the interaction between cells and with the growth substrate. Characterization was determined by the maximum (L max) and minimum (L min) distances between two cells within the colony and whether two lines that connect the two cells in the maximum and minimum distances intersect each other. Therefore, it can be recognized the colony shape in circular, oval, and irregular shapes. Simulation resulted that colony formation are mostly in oval shape with little branch. It also shows that greater cohesion strength obtains more compact colony formation.

  19. Social transfer of pathogenic fungus promotes active immunisation in ant colonies.

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    Matthias Konrad

    Full Text Available Due to the omnipresent risk of epidemics, insect societies have evolved sophisticated disease defences at the individual and colony level. An intriguing yet little understood phenomenon is that social contact to pathogen-exposed individuals reduces susceptibility of previously naive nestmates to this pathogen. We tested whether such social immunisation in Lasius ants against the entomopathogenic fungus Metarhizium anisopliae is based on active upregulation of the immune system of nestmates following contact to an infectious individual or passive protection via transfer of immune effectors among group members--that is, active versus passive immunisation. We found no evidence for involvement of passive immunisation via transfer of antimicrobials among colony members. Instead, intensive allogrooming behaviour between naive and pathogen-exposed ants before fungal conidia firmly attached to their cuticle suggested passage of the pathogen from the exposed individuals to their nestmates. By tracing fluorescence-labelled conidia we indeed detected frequent pathogen transfer to the nestmates, where they caused low-level infections as revealed by growth of small numbers of fungal colony forming units from their dissected body content. These infections rarely led to death, but instead promoted an enhanced ability to inhibit fungal growth and an active upregulation of immune genes involved in antifungal defences (defensin and prophenoloxidase, PPO. Contrarily, there was no upregulation of the gene cathepsin L, which is associated with antibacterial and antiviral defences, and we found no increased antibacterial activity of nestmates of fungus-exposed ants. This indicates that social immunisation after fungal exposure is specific, similar to recent findings for individual-level immune priming in invertebrates. Epidemiological modeling further suggests that active social immunisation is adaptive, as it leads to faster elimination of the disease and lower

  20. An observation study on the effects of queen age on some characteristics of honey bee colonies

    Directory of Open Access Journals (Sweden)

    Ibrahim Çakmak

    2010-01-01

    Full Text Available This study was conducted to determine the effects of the queen’s age on performance of the honeybee (A. mellifera anatoliaca colonies at nomad beekeeping conditions. Performances of the colonies, which had 0, 1, 2 and 3 year-old queens, were compared. The number of combs, brood areas, wintering ability survival rate and honey yield were determined as performance criteria. The average number of combs with bees throughout the experiment in Group I, Group II, Group III and Group IV was 10.92±0.78, 14.68±0.55, 10.10±0.60, 7.88±0.45 number combs/colony; the average of brood areas was 3078±372.5 cm2, 3668±460.3 cm2, 2215±294.0 cm2, 1665.38±241.8 cm2; the average of wintering ability was 84.3±2.9%, 88.0±3.7%, 46.6±19.0%, 26.8±16.5%; the survival rate was 100%, 100%, 60%, 40%; and the average of honey yields was 31.4±1.89 kg, 41.5±1.05 kg, 20.4±2.62 kg and 12.0±1.41 kg per colony, respectively. A significant and negative correlation between queen age and brood production (r=-80.2, colony strength (r=-62.5, wintering ability (r=-66 and honey yield (r=-75.6 were calculated (P<0.01. The colonies headed by young queens had more brood areas, longer worker colony population, better wintering ability and greater honey yield in comparison to colonies headed by old queens.

  1. Protective, restorative, and therapeutic properties of recombinant colony-stimulating factors

    International Nuclear Information System (INIS)

    Talmadge, J.E.; Tribble, H.; Pennington, R.; Bowersox, O.; Schneider, M.A.; Castelli, P.; Black, P.L.; Abe, F.

    1989-01-01

    Pretreatment of mice with recombinant murine (rM) colony-stimulating factor-granulocyte-macrophage (CSF-gm) or recombinant human (rH) CSF-g provides partial protection from the lethal effects of ionizing radiation or the alkylating agent cyclophosphamide (CTX). In addition, these agents can significantly prolong survival if administered following lethal doses of irradiation or CTX. To induce protective activity, cytokines were injected 20 hours before lethal irradiation or CTX administration. To accelerate recovery from lethal irradiation, the cytokines must be administered shortly following irradiation, and the induction of maximal levels of activity is dependent on chronic administration. In contrast, because of their longer half-lives, accelerated recovery from alkylating agents requires a delay of at least 24 to 48 hours to allow complete clearance of CTX before administration of a CSF. Studies quantitating peripheral blood leukocytes and bone marrow cellularity as well as colony-forming units per culture (CFU-C) frequency and CFU-C per femur revealed a significant correlation between these parameters and the ability to survive lethal irradiation

  2. Validation of a culturally modified short form of the McCarthy Scales of Children’s Abilities in 6 to 8 year old Zimbabwean school children: a cross section study

    Directory of Open Access Journals (Sweden)

    Kandawasvika Gwendoline Q

    2012-11-01

    Full Text Available Abstract Background The burden of cognitive impairment among school children from developing communities is under reported due to lack of culturally appropriate screening tools. The objective of this study was to validate a culturally modified short form of the McCarthy Scales of Children Abilities (MSCA in school children aged 6–8 years from varied backgrounds. Methods One hundred and one children aged 6–8 years attending mainstream classes were enrolled cross-sectionally from three schools: one rural and two urban. Two assessments were conducted on each child and the Short form MSCA was compared to an independent assessment by the educational psychologist. Results When comparing the results of the MSCA to local standard at -2SD, -1.5 SD and -1SD the sensitivity rates ranged from 17 to 50% with lower sensitivity at -2SD cut-off point. Specificity rates had less variation ranging from 95% to 100%. The number of children identified with cognitive impairment using -2SD, -1.5SD and -1SD below the mean for MSCA as a cut-off point were 3(3%, 7(7% and 13(13% respectively while the psychologist identified 18 (18%. The overall mean score on MSCA was 103 (SD 15. The rural children tended to score significantly lower marks compared to their peers from urban areas, mean (SD 98(15 and 107(15 respectively, p=0.006. There was no difference in the mean (SD scores between boys and girls, 103(17 and 103(15 respectively, p=0.995. Conclusion The culturally modified short form MSCA showed high specificity but low sensitivity. Prevalence of cognitive impairment among 6 to 8 year children was 3%. This figure is high when compared to developed communities.

  3. Frantz Fanon y la Enajenación del Negro y del Blanco en el Sistema Colonial

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    Ana Catarina Zema de Resende

    2016-11-01

    effects showing how alienation mechanisms determine the relationship between black and white and reproduce hierarchies governing these relationships. Adressing the thought of Fanon and recognizing the relevance and contemporaneity of his contributions is essential to reallocate the fight against all forms of domination in the continuing fight against colonialism in a time in which racial identity and racism have than proved their ability to persist in time and space. Keywords: Frantz Fanon; Alienation; Racism; Colonial System. Frantz Fanon  e a Alienação do Negro e do Branco no Sistema Colonial Resumo A partir da leitura de Pele negra, máscaras brancas, proponho neste artigo refletir sobre as ideias de Frantz Fanon acerca da alienação do negro e do branco no sistema colonial. O objetivo é recuperar alguns de seus aportes mais importantes para a compreensão do racismo colonial a partir de sua teoria da alienação. Fanon apresenta a alienação como uma etapa prévia à escravidão e ao colonialismo, necessária para a manutenção da exploração econômica e analisa as condutas identitárias de “vergonha de si” como resultado da dominação colonial. Ele descreve com precisão o impacto do racismo e do colonialismo e seus efeitos destrutivos mostrando como os mecanismos de alienação determinam as relações entre negros e brancos e reproduzem as hierarquias que regem essas relações. Retomar o pensamento de Fanon e reconhecer a relevância e atualidade de suas contribuições é fundamental para podermos realocar a luta contra todas as formas de dominação na continuidade da luta contra o colonialismo em uma época em que a identidade racial e o racismo mais que provaram sua capacidade de persistir no tempo e no espaço. Palavras-chave: Frantz Fanon; Alienação; Racismo; Sistema Colonial.

  4. Alternative Modernities for Colonial Korea

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    Steven Lee

    2016-06-01

    Full Text Available Sunyoung Park. The Proletarian Wave: Literature and Leftist Culture in Colonial Korea, 1910–1945. Cambridge, MA: Harvard University Asia Center, 2015. 348 pp. $50 (cloth. Vladimir Tikhonov. Modern Korea and Its Others: Perceptions of the Neighbouring Countries and Korean Modernity. London: Routledge, 2016. 218 pp. $160 (cloth. It has become a global scholarly undertaking: how to rethink modernity so as to decouple it from Westernization (Chakrabarty 2000. Strategies have included foregrounding the plurality of history to disrupt linear progress; positing non-Western centers of modernity in, say, Moscow or Shanghai; and tracing anticolonial circuits connecting Asia to Africa to Latin America. The two recent books under review here add colonial-era Korea to such far-reaching discussions by situating the country across national boundaries. Interestingly, one connecting thread here is the alternative world system provided by the interwar, Soviet-oriented Left. The result is an unsettling of binaries that subsequently became entrenched during the Cold War: for example, north-south, socialist-nationalist, and, for literature, realist-modernist. But more broadly, pervading both books is the sense that history could have turned out differently—that revisiting northeast Asia’s porous borders in the early twentieth century reveals the Korean peninsula’s lost, internationalist potential...

  5. Escalated convergent artificial bee colony

    Science.gov (United States)

    Jadon, Shimpi Singh; Bansal, Jagdish Chand; Tiwari, Ritu

    2016-03-01

    Artificial bee colony (ABC) optimisation algorithm is a recent, fast and easy-to-implement population-based meta heuristic for optimisation. ABC has been proved a rival algorithm with some popular swarm intelligence-based algorithms such as particle swarm optimisation, firefly algorithm and ant colony optimisation. The solution search equation of ABC is influenced by a random quantity which helps its search process in exploration at the cost of exploitation. In order to find a fast convergent behaviour of ABC while exploitation capability is maintained, in this paper basic ABC is modified in two ways. First, to improve exploitation capability, two local search strategies, namely classical unidimensional local search and levy flight random walk-based local search are incorporated with ABC. Furthermore, a new solution search strategy, namely stochastic diffusion scout search is proposed and incorporated into the scout bee phase to provide more chance to abandon solution to improve itself. Efficiency of the proposed algorithm is tested on 20 benchmark test functions of different complexities and characteristics. Results are very promising and they prove it to be a competitive algorithm in the field of swarm intelligence-based algorithms.

  6. Morphology offers no clues to asexual vs. sexual origin of small Acropora cervicornis (Scleractinia: Acroporidae colonies

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    D. E Williams

    2006-12-01

    Full Text Available Sexual recruitment of the staghorn coral, Acropora cervicornis, is accepted to be very rare. Instead, these branching corals proliferate through fragmentation leading to dense mono-specific and possibly monoclonal stands. For acroporid corals, which have suffered drastic population declines, dominance of asexual reproduction results in low levels of genotypic diversity and limited ability to re-colonize extirpated areas. Small colonies with a single encrusting, symmetrical base, and few incipient branches are frequently presumed to be the result of a settled planula (i.e. sexual reproduction. Here, we show that colonies fitting this description (i.e., presumed sexual recruits can result from asexual fragmentation. Acropora cervicornis colonies (~20 cm diameter were tagged and observed over eighteen months. In several cases, colony offshoots fused with the adjacent substrate forming secondary disc-like attachment points. Following natural fragmentation, these discs of tissue became separated from the original colony, and were observed to heal and give rise to smaller colonies with striking similarity to the expected morphology of a sexual recruit. Thus, presuming a colony is a sexual recruit based on appearance is unreliable and may lead to inflated expectations of genetic diversity among populations. The accurate assessment of recruitment and genetic diversity is crucial to predicting the recovery potential of these imperiled and ecologically irreplaceable reef corals. Rev. Biol. Trop. 54 (Suppl. 3: 145-151. Epub 2007 Jan. 15.Se ha aceptado que el reclutamiento sexual del coral asta de venado, Acropora cervicornis, es muy raro. Por el contrario, estos corales ramificados proliferan a través de fragmentación, generando densas bases monoespecíficas e incluso monoclonales. Para corales acropóridos, los cuales han sufrido disminuciones de población drásticas, la dominancia de reproducción asexual resulta en bajos niveles de diversidad genot

  7. Queen promiscuity lowers disease within honeybee colonies

    OpenAIRE

    Seeley, Thomas D; Tarpy, David R

    2006-01-01

    Most species of social insects have singly mated queens, but in some species each queen mates with numerous males to create a colony with a genetically diverse worker force. The adaptive significance of polyandry by social insect queens remains an evolutionary puzzle. Using the honeybee (Apis mellifera), we tested the hypothesis that polyandry improves a colony's resistance to disease. We established colonies headed by queens that had been artificially inseminated by either one or 10 drones. ...

  8. A Simple and Efficient Artificial Bee Colony Algorithm

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    Yunfeng Xu

    2013-01-01

    Full Text Available Artificial bee colony (ABC is a new population-based stochastic algorithm which has shown good search abilities on many optimization problems. However, the original ABC shows slow convergence speed during the search process. In order to enhance the performance of ABC, this paper proposes a new artificial bee colony (NABC algorithm, which modifies the search pattern of both employed and onlooker bees. A solution pool is constructed by storing some best solutions of the current swarm. New candidate solutions are generated by searching the neighborhood of solutions randomly chosen from the solution pool. Experiments are conducted on a set of twelve benchmark functions. Simulation results show that our approach is significantly better or at least comparable to the original ABC and seven other stochastic algorithms.

  9. Staphylococcus aureus small colony variants in diabetic foot infections

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    Estrella Cervantes-García

    2015-03-01

    Full Text Available Background: Staphylococcus aureus (S. aureus is one of the major pathogens causing chronic infections. The ability of S. aureus to acquire resistance to a diverse range of antimicrobial compounds results in limited treatment options, particularly in methicillin-resistant S. aureus (MRSA. A mechanism by which S. aureus develops reduced susceptibility to antimicrobials is through the formation of small colony variants (SCVs. Infections by SCVs of S. aureus are an upcoming problem due to difficulties in laboratory diagnosis and resistance to antimicrobial therapy. Methods: A prospective study was performed on 120 patients diagnosed with both type 2 diabetes mellitus and infected diabetic foot ulcers. The study was carried out from July 2012 to December 2013 in Hospital General de Mexico. The samples were cultured in blood agar, mannitol salt agar, and MacConkey agar media, and incubated at 37°C in aerobic conditions. Results: We describe the first known cases of diabetic foot infections caused by MRSA-SCVs in patients diagnosed with type 2 diabetes mellitus and infected diabetic foot ulcers. In all of our cases, the patients had not received any form of gentamicin therapy. Conclusions: The antibiotic therapy commonly used in diabetic patients with infected diabetic foot ulcers fails in the case of MRSA-SCVs because the intracellular location protects S. aureus-SCVs from the host's defenses and also helps them resist antibiotics. The cases studied in this article add to the spectrum of persistent and relapsing infections attributed to MRSA-SCVs and emphasizes that these variants may also play a relevant role in diabetic foot infections.

  10. Distribution of Paenibacillus larvae spores inside honey bee colonies and its relevance for diagnosis.

    Science.gov (United States)

    Gillard, M; Charriere, J D; Belloy, L

    2008-09-01

    One of the most important factors affecting the development of honey bee colonies is infectious diseases such as American foulbrood (AFB) caused by the spore forming Gram-positive bacterium Paenibacillus larvae. Colony inspections for AFB clinical symptoms are time consuming. Moreover, diseased cells in the early stages of the infection may easily be overlooked. In this study, we investigated whether it is possible to determine the sanitary status of a colony based on analyses of different materials collected from the hive. We analysed 237 bee samples and 67 honey samples originating from 71 colonies situated in 13 apiaries with clinical AFB occurrences. We tested whether a difference in spore load among bees inside the whole hive exists and which sample material related to its location inside the hive was the most appropriate for an early AFB diagnosis based on the culture method. Results indicated that diagnostics based on analysis of honey samples and bees collected at the hive entrance are of limited value as only 86% and 83%, respectively, of samples from AFB-symptomatic colonies were positive. Analysis of bee samples collected from the brood nest, honey chamber, and edge frame allowed the detection of all colonies showing AFB clinical symptoms. Microbiological analysis showed that more than one quarter of samples collected from colonies without AFB clinical symptoms were positive for P. larvae. Based on these results, we recommend investigating colonies by testing bee samples from the brood nest, edge frame or honey chamber for P. larvae spores.

  11. Conspecific and not performance-based attraction on immigrants drives colony growth in a waterbird.

    Science.gov (United States)

    Tenan, Simone; Fasola, Mauro; Volponi, Stefano; Tavecchia, Giacomo

    2017-09-01

    Local recruitment and immigration play an important part in the dynamics and growth of animal populations. However, their estimation and incorporation into open population models is, in most cases, problematic. We studied factors affecting the growth of a recently established colony of Eurasian spoonbill (Platalea leucorodia) and assessed the contribution of local recruits, i.e. birds born in the colony, and immigrants, i.e. birds of unknown origin, to colony growth. We applied an integrated population model that accounts for uncertainty in breeding state assignment and merges population surveys, local fecundity and individual longitudinal data of breeding and non-breeding birds, to estimate demographic rates and the relative role of recruitment and immigration in driving the local dynamics. We also used this analytical framework to assess the degree of support for the 'performance-based' and 'conspecific attraction' hypotheses as possible mechanisms of colony growth. Among the demographic rates, only immigration was positively and significantly correlated with population growth rate. In addition, the number of immigrants settling in the colony was positively correlated with colony size in the previous and current year, but was not correlated with fecundity of the previous year. Our results suggest that the variation in immigration affected colony dynamics and that conspecific attraction likely triggered the relevant role of immigration in the growth of a recently formed waterbird colony, supporting the need of including immigration in population analysis. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

  12. How can bee colony algorithm serve medicine?

    Science.gov (United States)

    Salehahmadi, Zeinab; Manafi, Amir

    2014-07-01

    Healthcare professionals usually should make complex decisions with far reaching consequences and associated risks in health care fields. As it was demonstrated in other industries, the ability to drill down into pertinent data to explore knowledge behind the data can greatly facilitate superior, informed decisions to ensue the facts. Nature has always inspired researchers to develop models of solving the problems. Bee colony algorithm (BCA), based on the self-organized behavior of social insects is one of the most popular member of the family of population oriented, nature inspired meta-heuristic swarm intelligence method which has been proved its superiority over some other nature inspired algorithms. The objective of this model was to identify valid novel, potentially useful, and understandable correlations and patterns in existing data. This review employs a thematic analysis of online series of academic papers to outline BCA in medical hive, reducing the response and computational time and optimizing the problems. To illustrate the benefits of this model, the cases of disease diagnose system are presented.

  13. Surveys of murre colony attendance in the northern Gulf of Alaska following the Exxon Valdez oil spill

    International Nuclear Information System (INIS)

    Erikson, D.E.

    1995-01-01

    Field surveys were conducted in July and August 1991 on 32 of the 36 murre (Uria spp.) colonies in the northern Gulf of Alaska to assess colony attendance (number of birds present at a colony) two years after the exxon Valdez oil spill. The surveys focused on murre colonies because murres represented 74% of the recovered seabird carcasses and because it had claimed that there was large-scale mortality of murres, leading to 60% to 70% decreases at some large colonies and population recovery periods of 20 to 70 years. Murres were present at all 32 colonies, and colony attendance estimates were generally similar to those from historical (prespill) surveys, particularly for those colonies in the direct path of the spill, i.e., the Barren Islands and Chiswell islands. Colony attendance levels in 1991 do not support the contention that murre colony attendance in the study area was drastically lower than historical levels. When colonies were grouped according to risk of oil exposure, the mean changes in attendance between 1991 and historical murre surveys did not differ significantly among the groups. Factors that could account for the observed similarity of 1991 and historical murre counts despite the high estimated mortality are (1) overestimation of mortality or (2) replacement of lost breeders through either recruitment of formerly nonbreeding individuals into the breeding population at spill-affected colonies or immigration of murres form nonaffected colonies. The findings of this study suggest that impacts of the Exxon Valdez oil spill on murre colony attendance in the northern Gulf of alaska were relatively short-term. 118 refs., 5 figs., 8 tabs

  14. Understanding Long-Run African Growth : Colonial Institutions or Colonial Education?

    NARCIS (Netherlands)

    Bolt, J.; Bezemer, D.J.

    2009-01-01

    Long-term growth in developing countries has been explained in four frameworks: 'extractive colonial institutions' (Acemoglu et al., 2001), 'colonial legal origin' (La Porta et al., 2004), 'geography' (Gallup et al., 1998) and 'colonial human capital' (Glaeser et al., 2004). In this paper we test

  15. Ecophysiology of gelatinous Nostoc colonies: unprecedented slow growth and survival in resource-poor and harsh environments.

    Science.gov (United States)

    Sand-Jensen, Kaj

    2014-07-01

    The cyanobacterial genus Nostoc includes several species forming centimetre-large gelatinous colonies in nutrient-poor freshwaters and harsh semi-terrestrial environments with extended drought or freezing. These Nostoc species have filaments with normal photosynthetic cells and N2-fixing heterocysts embedded in an extensive gelatinous matrix of polysaccharides and many other organic substances providing biological and environmental protection. Large colony size imposes constraints on the use of external resources and the gelatinous matrix represents extra costs and reduced growth rates. The objective of this review is to evaluate the mechanisms behind the low rates of growth and mortality, protection against environmental hazards and the persistence and longevity of gelatinous Nostoc colonies, and their ability to economize with highly limiting resources. Simple models predict the decline in uptake of dissolved inorganic carbon (DIC) and a decline in the growth rate of spherical freshwater colonies of N. pruniforme and N. zetterstedtii and sheet-like colonies of N. commune in response to a thicker diffusion boundary layer, lower external DIC concentration and higher organic carbon mass per surface area (CMA) of the colony. Measured growth rates of N. commune and N. pruniforme at high DIC availability comply with general empirical predictions of maximum growth rate (i.e. doubling time 10-14 d) as functions of CMA for marine macroalgae and as functions of tissue thickness for aquatic and terrestrial plants, while extremely low growth rates of N. zetterstedtii (i.e. doubling time 2-3 years) are 10-fold lower than model predictions, either because of very low ambient DIC and/or an extremely costly colony matrix. DIC uptake is limited by diffusion at low concentrations for all species, although they exhibit efficient HCO3(-) uptake, accumulation of respiratory DIC within the colonies and very low CO2 compensation points. Long light paths and light attenuation by

  16. Resilience of honeybee colonies via common stomach: A model of self-regulation of foraging.

    Directory of Open Access Journals (Sweden)

    Thomas Schmickl

    Full Text Available We propose a new regulation mechanism based on the idea of the "common stomach" to explain several aspects of the resilience and homeostatic regulation of honeybee colonies. This mechanism exploits shared pools of substances (pollen, nectar, workers, brood that modulate recruitment, abandonment and allocation patterns at the colony-level and enable bees to perform several survival strategies to cope with difficult circumstances: Lack of proteins leads to reduced feeding of young brood, to early capping of old brood and to regaining of already spent proteins through brood cannibalism. We modeled this system by linear interaction terms and mass-action law. To test the predictive power of the model of this regulatory mechanism we compared our model predictions to experimental data of several studies. These comparisons show that the proposed regulation mechanism can explain a variety of colony level behaviors. Detailed analysis of the model revealed that these mechanisms could explain the resilience, stability and self-regulation observed in honeybee colonies. We found that manipulation of material flow and applying sudden perturbations to colony stocks are quickly compensated by a resulting counter-acting shift in task selection. Selective analysis of feedback loops allowed us to discriminate the importance of different feedback loops in self-regulation of honeybee colonies. We stress that a network of simple proximate mechanisms can explain significant colony-level abilities that can also be seen as ultimate reasoning of the evolutionary trajectory of honeybees.

  17. Post-Colonialism Perspectives on Educational Competition

    Science.gov (United States)

    Yeh, Chuan-Rong

    2016-01-01

    Educational competition has always been the puzzle issue of educational researches. In this article, I analyze several aspects of educational competition within the perspective of post-colonialism discourse. In the political aspect, Taiwanese education is linked with political power, to present the post-colonial spirit by continuing dynastic…

  18. [Notes about other epidemics in Colonial Chile].

    Science.gov (United States)

    Laval, Enrique

    2015-10-01

    In chronicles or in the historiography of the Colony in Chile there are few references about epidemics different to smallpox; like typhus, typhoid fever, dysentery, etc. Almost all, fast spreading in the country and some with high lethality, which led to overflowing the capacity of hospitals in the Chilean colonial period.

  19. Diffuse colonies of human skin fibroblasts in relation to cellular senescence and proliferation.

    Science.gov (United States)

    Zorin, Vadim; Zorina, Alla; Smetanina, Nadezhda; Kopnin, Pavel; Ozerov, Ivan V; Leonov, Sergey; Isaev, Artur; Klokov, Dmitry; Osipov, Andreyan N

    2017-05-16

    Development of personalized skin treatment in medicine and skin care may benefit from simple and accurate evaluation of the fraction of senescent skin fibroblasts that lost their proliferative capacity. We examined whether enriched analysis of colonies formed by primary human skin fibroblasts, a simple and widely available cellular assay, could reveal correlations with the fraction of senescent cells in heterogenic cell population. We measured fractions of senescence associated β-galactosidase (SA-βgal) positive cells in either mass cultures or colonies of various morphological types (dense, mixed and diffuse) formed by skin fibroblasts from 10 human donors. Although the donors were chosen to be within the same age group (33-54 years), the colony forming efficiency of their fibroblasts (ECO-f) and the percentage of dense, mixed and diffuse colonies varied greatly among the donors. We showed, for the first time, that the SA-βgal positive fraction was the largest in diffuse colonies, confirming that they originated from cells with the least proliferative capacity. The percentage of diffuse colonies was also found to correlate with the SA-βgal positive cells in mass culture. Using Ki67 as a cell proliferation marker, we further demonstrated a strong inverse correlation (r=-0.85, p=0.02) between the percentage of diffuse colonies and the fraction of Ki67+ cells. Moreover, a significant inverse correlation (r=-0.94, p=0.0001) between the percentage of diffuse colonies and ECO-f was found. Our data indicate that quantification of a fraction of diffuse colonies may provide a simple and useful method to evaluate the extent of cellular senescence in human skin fibroblasts.

  20. From conquest to independence: the nigerian colonial experience

    Directory of Open Access Journals (Sweden)

    Tunde Oduwobi

    2011-06-01

    Niger. Such, however, was the character of the British penetration that when in 1900 political control was formally established over the Nigerian area it took the tripartite form of three autonomous administrations. These three became subsequently amalgamated in 1914 to form the Nigerian state; yet the tripartite administrative traditions were not obliterated and they remained as latent forces modifying the country’s historical development. Thus, at the twilight of the colonial period, Nigerian nationalism, developing as it was to terminate British colonialism, became negatively adulterated by ethnic nationalism resting on the strong pillars of the tripartite traditions fostered by British colonial rule. The Nigerian state therefore emerged from colonialism with the problem of forging political unity.Keywords:.Nigeria, colonialism, independence

  1. Hegemony and Accommodation in the History Curriculum in Colonial Botswana

    Science.gov (United States)

    Mafela, Lily

    2014-01-01

    A reanalysis of colonial education is necessary in order to highlight its multifaceted and hybrid nature in specific colonial contexts. Although in general, colonial education served the socio-political needs of the colonial machinery, the colonial government's hegemonic authority over the school curriculum did not operate as a totalising project.…

  2. Drastic influence of minor Fe or Co additions on the glass forming ability, martensitic transformations and mechanical properties of shape memory Zr-Cu-Al bulk metallic glass composites.

    Science.gov (United States)

    González, Sergio; Pérez, Pablo; Rossinyol, Emma; Suriñach, Santiago; Dolors Baró, Maria; Pellicer, Eva; Sort, Jordi

    2014-06-01

    The microstructure and mechanical properties of Zr 48 Cu 48 -  x Al 4 M x (M ≡ Fe or Co, x  = 0, 0.5, 1 at.%) metallic glass (MG) composites are highly dependent on the amount of Fe or Co added as microalloying elements in the parent Zr 48 Cu 48 Al 4 material. Addition of Fe and Co promotes the transformation from austenite to martensite during the course of nanoindentation or compression experiments, resulting in an enhancement of plasticity. However, the presence of Fe or Co also reduces the glass forming ability, ultimately causing a worsening of the mechanical properties. Owing to the interplay between these two effects, the compressive plasticity for alloys with x  = 0.5 (5.5% in Zr 48 Cu 47.5 Al 4 Co 0.5 and 6.2% in Zr 48 Cu 47.5 Al 4 Fe 0.5 ) is considerably larger than for Zr 48 Cu 48 Al 4 or the alloys with x  = 1. Slight variations in the Young's modulus (around 5-10%) and significant changes in the yield stress (up to 25%) are also observed depending on the composition. The different microstructural factors that have an influence on the mechanical behavior of these composites are investigated in detail: (i) co-existence of amorphous and crystalline phases in the as-cast state, (ii) nature of the crystalline phases (austenite versus martensite content), and (iii) propensity for the austenite to undergo a mechanically-driven martensitic transformation during plastic deformation. Evidence for intragranular nanotwins likely generated in the course of the austenite-martensite transformation is provided by transmission electron microscopy. Our results reveal that fine-tuning of the composition of the Zr-Cu-Al-(Fe,Co) system is crucial in order to optimize the mechanical performance of these bulk MG composites, to make them suitable materials for structural applications.

  3. Keratin subsidies promote feather decomposition via an increase in keratin-consuming arthropods and microorganisms in bird breeding colonies.

    Science.gov (United States)

    Sugiura, Shinji; Masuya, Hayato

    2015-06-01

    Resource subsidies are well known to increase population densities of consumers. The decomposition process of these subsidised resources can be influenced by increasing consumer abundance. However, few studies have assessed whether resource subsidies can promote resource decomposition via a population increase in consumers. Here, we examined the effects of keratin subsidies on feather decomposition in egret and heron breeding colonies. Egrets and herons (Ardeidae) frequently breed in inland forests and provide large amounts of keratin materials to the forest floor in the form of feathers of chicks (that die). We compared the decrease in the weights of egret and heron feathers (experimentally placed on the forest floor) over a 12-month period among egret/heron breeding colonies (five sites) and areas outside of colonies (five sites) in central Japan. Of the feathers placed experimentally on forest floors, 92-97 % and 99-100 % in colonies and 47-50 % and 71-90 % in non-colony areas were decomposed after 4 and 12 months, respectively. Then, decomposition rates of feathers were faster in colonies than in areas outside of colonies, suggesting that keratin subsidies can promote feather decomposition in colonies. Field observations and laboratory experiments indicated that keratin-feeding arthropods and keratinophilic fungi played important roles in feather decomposition. Therefore, scavenging arthropods and keratinophilic fungi, which dramatically increased in egret and heron breeding colonies, could accelerate the decomposition of feathers supplied to the forest floor of colonies.

  4. Ant Colony Algorithm and Simulation for Robust Airport Gate Assignment

    Directory of Open Access Journals (Sweden)

    Hui Zhao

    2014-01-01

    Full Text Available Airport gate assignment is core task for airport ground operations. Due to the fact that the departure and arrival time of flights may be influenced by many random factors, the airport gate assignment scheme may encounter gate conflict and many other problems. This paper aims at finding a robust solution for airport gate assignment problem. A mixed integer model is proposed to formulate the problem, and colony algorithm is designed to solve this model. Simulation result shows that, in consideration of robustness, the ability of antidisturbance for airport gate assignment scheme has much improved.

  5. Impedimetric quantification of the formation process and the chemosensitivity of cancer cell colonies suspended in 3D environment.

    Science.gov (United States)

    Lei, Kin Fong; Wu, Zong-Ming; Huang, Chia-Hao

    2015-12-15

    In cancer research, colony formation assay is a gold standard for the investigation of the development of early tumors and the effects of cytotoxic agents on tumors in vitro. Quantification of cancer cell colonies suspended in hydrogel is currently achieved by manual counting under microscope. It is challenging to microscopically quantify the colony number and size without subjective bias. In this work, impedimetric quantification of cancer cell colonies suspended in hydrogel was successfully developed and provides a quantitative and objective method to describe the colony formation process and the development of colony size during the culture course. A biosensor embedded with a pair of parallel plate electrodes was fabricated for the impedimetric quantification. Cancer cell (cell line: Huh-7) were encapsulated in methyl cellulose hydrogel and cultured to gradually form cancer cell colonies suspended in 3D environment. At pre-set schedule during the culture course, small volume (50 μL) of colonies/MC hydrogel was collected, mixed with measurement hydrogel, and loaded to the biosensor for measurement. Hence, the colony formation process could be quantitatively represented by a colony index and a colony size index calculated from electrical impedance. Based on these developments, chemosensitivity of cancer cell colonies under different concentrations of anti-cancer drug, i.e., doxorubicin, was quantitatively investigated to study the efficacy of anti-cancer drug. Also, dose-response curve was constructed to calculate the IC50 value, which is an important indicator for chemosensitivity assay. These results showed the impedimetric quantification is a promising technique for the colony formation assay. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Indonesian Chinese in the Netherlands and the legacies of violence in colonial and post-colonial Indonesia

    Directory of Open Access Journals (Sweden)

    Alexander van der Meer

    2017-04-01

    Full Text Available After Indonesian independence in 1945, thousands of Indonesian Chinese repatriated to the Netherlands, the former colonizer. As opposed to other repatriates from Indonesia, who organized themselves into pressure groups and fought for a place in the national memory culture, the Indonesian Chinese in the Netherlands only formed strict socio-cultural associations and have generally stayed clear of identity politics. Usually, this divergence is attributed to the smooth integration and socio-economic success of the latter group, as well as to Chinese values, such as conflict avoidance.This article adds to this explanation by positing that this phenomenon has also been induced by the legacy of anti-Chinese violence in colonial and post-colonial Indonesia: respectively, Dutch discomfort to acknowledge the violent and discriminatory elements of its own colonial history, as well as a fear of offending the Indonesian government. Consequently, many Indonesian Chinese in the Netherlands have engaged in some form of public self-silencing.

  7. 21 CFR 866.2170 - Automated colony counter.

    Science.gov (United States)

    2010-04-01

    ...) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2170 Automated colony counter. (a) Identification. An automated colony counter is a mechanical device intended for medical...

  8. Endogenous Sheet-Averaged Tension Within a Large Epithelial Cell Colony.

    Science.gov (United States)

    Dumbali, Sandeep P; Mei, Lanju; Qian, Shizhi; Maruthamuthu, Venkat

    2017-10-01

    Epithelial cells form quasi-two-dimensional sheets that function as contractile media to effect tissue shape changes during development and homeostasis. Endogenously generated intrasheet tension is a driver of such changes, but has predominantly been measured in the presence of directional migration. The nature of epithelial cell-generated forces transmitted over supracellular distances, in the absence of directional migration, is thus largely unclear. In this report, we consider large epithelial cell colonies which are archetypical multicell collectives with extensive cell-cell contacts but with a symmetric (circular) boundary. Using the traction force imbalance method (TFIM) (traction force microscopy combined with physical force balance), we first show that one can determine the colony-level endogenous sheet forces exerted at the midline by one half of the colony on the other half with no prior assumptions on the uniformity of the mechanical properties of the cell sheet. Importantly, we find that this colony-level sheet force exhibits large variations with orientation-the difference between the maximum and minimum sheet force is comparable to the average sheet force itself. Furthermore, the sheet force at the colony midline is largely tensile but the shear component exhibits significantly more variation with orientation. We thus show that even an unperturbed epithelial colony with a symmetric boundary shows significant directional variation in the endogenous sheet tension and shear forces that subsist at the colony level.

  9. Human T cell colony formation in microculture: analysis of growth requirements and functional activities.

    Science.gov (United States)

    Gelfand, E W; Lee, J W; Dosch, H M; Price, G B

    1981-03-01

    A microculture method in methylcellulose has been developed for the study of human T cell colony formation. The technique is simple, reliable, does not require preincubation with lectin and requires small numbers of cells. Colony formation was dependent on the presence of phytohemagglutin-conditioned medium, a T colony precursor cell (TCPC), and a "helper" or accessory T cell. Plating efficiency was increased 10-fold in the presence of irradiated feeder cells. Progenitors of the T colony cells were identified in peripheral blood, tonsil, and spleen but not in thymus or thoracic duct. They were isolated in the E-rosetting, theophylline-resistant, Fc-IgG-negative cell populations. In peripheral blood the frequency of TCPC and accessory cells, the T colony forming unit, was estimated to be 8 X 10(-3). Colony cells proliferated in response to lectins and allogeneic cells. Forty to 80% of the cells were Ia-positive and stimulated both autologous and allogeneic mixed lymphocyte responses. They were incapable of mediating antibody-dependent cytotoxicity. In contrast, they were effective in assays of spontaneous cytotoxicity but only against certain target cells. This method for the analysis of T colony formation should prove valuable in the functional analysis of T cell subsets in immunodeficiency states or the transplant recipient.

  10. Spatial variation in age structure among colonies of a marine snake: the influence of ectothermy.

    Science.gov (United States)

    Bonnet, Xavier; Brischoux, François; Pinaud, David; Michel, Catherine Louise; Clobert, Jean; Shine, Richard; Fauvel, Thomas

    2015-07-01

    Several tetrapod lineages that have evolved to exploit marine environments (e.g. seals, seabirds, sea kraits) continue to rely upon land for reproduction and, thus, form dense colonies on suitable islands. In birds and mammals (endotherms), the offspring cannot survive without their parents. Terrestrial colonies contain all age classes. In reptiles (ectotherms), this constraint is relaxed, because offspring are independent from birth. Hence, each age class has the potential to select sites with characteristics that favour them. Our studies of sea snakes (sea kraits) in the lagoon of New Caledonia reveal marked spatial heterogeneity in age structure among colonies. Sea krait colonies exhibit the endothermic 'seal-seabird' pattern (mixed-age classes within populations) only where the lagoon is narrow. Where the lagoon is wide, most snake colonies are comprised primarily of a single age cohort. Nurseries are located near the coast, adult colonies offshore and mixed colonies in-between. We suggest that ectothermy allows individuals to utilize habitats that are best suited to their own ecological requirements, a flexibility not available to endothermic marine taxa with obligate parental care. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

  11. Colonial Taxation, Corruption and Resistance in Igbominaland ...

    African Journals Online (AJOL)

    Colonial Taxation, Corruption and Resistance in Igbominaland. ... AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search · USING AJOL · RESOURCES ... While taxation definitely stimulated economic activities in Igbominaland at ...

  12. Post-colonial identity in Greenland?

    DEFF Research Database (Denmark)

    Gad, Ulrik Pram

    2009-01-01

    could be furthered by bringing politics back in. Based on a discourse analysis of the Greenlandic debate on language, this paper makes three claims: First, the identity projects promoted in Greenland are based on an essentialist conception of identity. Secondly, Greenlandic identity discourse combines......In the gradual unravelling of Greenland’s colonial relationship to Denmark, an essentialist conceptualization of Greenlandic identity has played a significant role. However, both our scholarly understanding of post-colonial Greenlandic identity and the process towards independence for Greenland...... elements of traditional Inuit culture and elements of colonial modernity. Thirdly, monolingual Greenlanders are those with the most to gain from abandoning the dichotomy of essentialist identities. Strategically, the paper suggests a post-post-colonial Greenlandic identity as a means of avoiding...

  13. Acute leukemia after radiotherapy in a patient with Turcot's syndrome. Impaired colony formation in skin fibroblast cultures after irradiation

    International Nuclear Information System (INIS)

    Li, F.P.; Little, J.B.; Bech-Hansen, N.T.; Paterson, M.C.; Arlett, C.; Garnick, M.B.; Mayer, R.J.

    1983-01-01

    Colonic polyposis and carcinoma developed in a woman with Turcot's syndrome at the age of 31 years; astrocytoma developed when she was 37. Her brother and sister had died of astrocytoma at the ages of 18 and 33 years, respectively. Progressive neutropenia developed in the patient three months after radiotherapy for her brain tumor and acute myelomonocytic leukemia 19 months after treatment. Three laboratories independently evaluated cultures of her skin fibroblasts for in vitro sensitivity to cell killing (loss of colony-forming ability) by x-rays. Survival assays consistently revealed slight but significant radiosensitivity in an early-passage (six to 10 doublings) fibroblast subculture. A later subculture (21 to 29 doublings) showed no abnormality, a possible effect of selective in vitro loss of radiosensitive cells

  14. Negotiating Colonial Korean Cinema in the Japanese Empire: From the Silent Era to the Talkies, 1923-1939

    Directory of Open Access Journals (Sweden)

    Chonghwa Chung

    2012-12-01

    Full Text Available This article examines what I call a “system of cooperation” (K. hyŏp’ŏp, J. kyōgyō, 協業 in the colonial Korean film industry from 1923, when silent films appeared, to the late 1930s, when colonial cinema was restructured within an imperial wartime system. In other words, this article examines the interworking of colonial Korean and imperial Japanese cinema from Yun Hae-dong’s “colonial modern” perspective in order to go beyond the long established lens on colonial Korean film and film historiography that merely focused on the contributions of colonial Korean filmmakers. Here the author rather focuses on the cooperation or collaboration between Japan and Korea: Japanese directors and cinematographers working in Korea, Korean filmmakers with experience in the Japanese apprenticeship system, and filmmakers working together and independently during the silent film era. During the transition from the silent to the early talkie eras, second-generation filmmakers, especially those who trained in film studios in Japan, were significant. They dreamed of the corporatization of the colonial Korean film industry and took the lead in coproductions between Japanese film companies and their colonial Korean counterparts. Korean filmmakers were not unilaterally suppressed by imperial Japan, nor did they independently operate within the Korean film industry during the colonial period. The Japanese in colonial Korea did not take the lead in forming the colonial Korean film scene, either. The core formation of colonial Korean / Korean film was a process of Korean and Japanese filmmakers in competition and negotiation with one another within a complex film sphere launched with Japanese capital and technology.

  15. Edo N'ekue Phenomenon: A Study in Pre-colonial Benin Imperialism ...

    African Journals Online (AJOL)

    Most societies in pre-colonial times experienced one form of relationship or the other with their neighbours. More often than not, these relationships came in form of commercial, cultural and political relations. Characteristic of these relations were intermarriages, linguistic borrowings and other interactions dictated by the ...

  16. Heroines of lonely outposts or tools of the empire? British nurses in Britain's model colony: Ceylon, 1878-1948.

    Science.gov (United States)

    Jones, Margaret

    2004-09-01

    In 1878 two 'Nightingale' nurses arrived in the British colony of Ceylon to initiate a training programme for indigenous women in the skills and values of what was then termed 'scientific nursing'. These two women were the first of a succession of British women who went to the colony to nurse in its hospitals and to train Ceylonese women for the profession. Using the official records of the colonial government held in the National Archives, Kew and the records of the Overseas Nursing Association in the Rhodes House Collection, Oxford, this paper explores both the professional and social experiences of these women. This paper also analyses the role that these representatives of the colonial state played in the development of an indigenous nursing profession and concludes that their presence in the colony ultimately left an ambiguous legacy. In their role as trainers of indigenous women, they furthered the development and spread of a Western nursing profession in the colony's hospitals. At the same time, however, their continuing dominance of training and the positions of responsibility was an inhibiting factor in the ability of indigenous nurses to organise and professionalise. Whereas the doctors, trained in the colony's Medical College, achieved registration as early as 1905, the nurses had to wait until 1949, a year after independence, before their qualification was recognised and protected. Nursing remained throughout the colonial period therefore, even more so than at the metropolitan centre, the 'Cinderella' of the medical professions.

  17. The cabABC Operon Essential for Biofilm and Rugose Colony Development in Vibrio vulnificus.

    Directory of Open Access Journals (Sweden)

    Jin Hwan Park

    2015-09-01

    Full Text Available A transcriptome analysis identified Vibrio vulnificus cabABC genes which were preferentially expressed in biofilms. The cabABC genes were transcribed as a single operon. The cabA gene was induced by elevated 3',5'-cyclic diguanylic acid (c-di-GMP and encoded a calcium-binding protein CabA. Comparison of the biofilms produced by the cabA mutant and its parent strain JN111 in microtiter plates using crystal-violet staining demonstrated that CabA contributed to biofilm formation in a calcium-dependent manner under elevated c-di-GMP conditions. Genetic and biochemical analyses revealed that CabA was secreted to the cell exterior through functional CabB and CabC, distributed throughout the biofilm matrix, and produced as the biofilm matured. These results, together with the observation that CabA also contributes to the development of rugose colony morphology, indicated that CabA is a matrix-associated protein required for maturation, rather than adhesion involved in the initial attachment, of biofilms. Microscopic comparison of the structure of biofilms produced by JN111 and the cabA mutant demonstrated that CabA is an extracellular matrix component essential for the development of the mature biofilm structures in flow cells and on oyster shells. Exogenously providing purified CabA restored the biofilm- and rugose colony-forming abilities of the cabA mutant when calcium was available. Circular dichroism and size exclusion analyses revealed that calcium binding induces CabA conformational changes which may lead to multimerization. Extracellular complementation experiments revealed that CabA can assemble a functional matrix only when exopolysaccharides coexist. Consequently, the combined results suggested that CabA is a structural protein of the extracellular matrix and multimerizes to a conformation functional in building robust biofilms, which may render V. vulnificus to survive in hostile environments and reach a concentrated infective dose.

  18. Sphingomonas from petroleum-contaminated soils in Shenfu, China and their PAHs degradation abilities

    Directory of Open Access Journals (Sweden)

    Lisha Zhou

    2016-06-01

    Full Text Available Abstract Members of the Sphingomonas genus are often isolated from petroleum-contaminated soils due to their unique abilities to degrade polycyclic aromatic hydrocarbons (PAHs, which are important for in situ bioremediation. In this study, a combined phenotypic and genotypic approach using streptomycin-containing medium and Sphingomonas -specific PCR was developed to isolate and identify culturable Sphingomonas strains present in petroleum-contaminated soils in the Shenfu wastewater irrigation zone. Of the 15 soil samples examined, 12 soils yielded yellow streptomycin-resistant colonies. The largest number of yellow colony-forming units (CFUs could reach 105 CFUs g-1 soil. The number of yellow CFUs had a significant positive correlation (p < 0.05 with the ratio of PAHs to total petroleum hydrocarbons (TPH, indicating that Sphingomonas may play a key role in degrading the PAH fraction of the petroleum contaminants at this site. Sixty yellow colonies were selected randomly and analyzed by colony PCR using Sphingomonas -specific primers, out of which 48 isolates had PCR-positive signals. The 48 positive amplicons generated 8 distinct restriction fragment length polymorphism (RFLP patterns, and 7 out of 8 phylotypes were identified as Sphingomonas by 16S rRNA gene sequencing of the representative strains. Within these 7 Sphingomonas strains, 6 strains were capable of using fluorene as the sole carbon source, while 2 strains were phenanthrene-degrading Sphingomonas. To the best of our knowledge, this is the first report to evaluate the relationship between PAHs contamination levels and culturable Sphingomonas in environmental samples.

  19. Colony variation of Helicobacter pylori: pathogenic potential is correlated to cell wall lipid composition.

    Science.gov (United States)

    Bukholm, G; Tannaes, T; Nedenskov, P; Esbensen, Y; Grav, H J; Hovig, T; Ariansen, S; Guldvog, I

    1997-05-01

    Differences in expression of disease after infection with Helicobacter pylori have so far been connected with host factors and bacterial interstrain variation. In this study, spontaneous and ecology-mediated intrastrain variation was examined. Four clinical isolates of H. pylori were shown to give rise to two colony forms. Bacterial morphology was examined by electron microscopy. Bacterial fractions were examined for proteins using ion exchange chromatography and SDS-PAGE; for lipids using thin-layer chromatography, lipid anion-exchange chromatography, column chromatography on silica gel, 31P-NMR, gas chromatography and mass spectrometry. Bacterial in vitro invasiveness and adhesiveness were examined in two different systems, and urease and VacA toxin were assayed by Western blot analysis. H. pylori was shown to give rise to two colony forms: at normal pH the population was dominated by L colonies. One strain was chosen for further studies. Bacteria from L colonies retained VacA toxin and urease, did not invade or adhere to epithelial cells, and contained normal quantities of phosphatidylethanolamine. In a small frequency, spontaneous S colonies were formed. Bacteria from these colonies released VacA and urease, adhered to and invaded epithelial cells and contained increased amounts of lysophosphatidyl ethanolamine and phosphatidyl serine. After addition of HCl to the culture medium (pH6), almost only S colonies were formed. The results demonstrate that environmental factors, such as HCl, can change the bacterial cell wall, and thereby enhance expression of virulence factors of H. pylori in vitro. A similar in vivo variation would have implications for our understanding of the interaction between HCl secretion in the gastric mucosa and H. pylori in the development of peptic ulcer disease.

  20. Homologous stress adaptation, antibiotic resistance, and biofilm forming ability of Salmonella enterica serovar Heidelberg (ATCC8326) on different food-contact surfaces following exposure to sub-lethal chlorine concentrations

    Science.gov (United States)

    Salmonella enterica serovar Heidelberg (American Type Culture Collection; ATCC 8326) was examined for the ability to adapt to the homologous stress of chlorine through exposure to increasing chlorine concentrations (25 ppm daily increments) in tryptic soy broth (TSB). The tested strain exhibited an ...

  1. Ability Dispersion and Team Performance

    DEFF Research Database (Denmark)

    Hoogendoorn, Sander; Parker, Simon C.; Van Praag, Mirjam

    What is the effect of dispersed levels of cognitive ability of members of a (business) team on their team's performance? This paper reports the results of a field experiment in which 573 students in 49 (student) teams start up and manage real companies under identical circumstances for one year. We...... ensured exogenous variation in otherwise random team composition by assigning students to teams based on their measured cognitive abilities. Each team performs a variety of tasks, often involving complex decision making. The key result of the experiment is that the performance of business teams first...... increases and then decreases with ability dispersion. We seek to understand this finding by developing a model in which team members of different ability levels form sub- teams with other team members with similar ability levels to specialize in different productive tasks. Diversity spreads production over...

  2. Evaluation of drug-induced hematotoxicity using novel in vitro monkey CFU-GM and BFU-E colony assays.

    Science.gov (United States)

    Goto, Koichi; Goto, Mayumi; Ando-Imaoka, Masako; Kai, Kiyonori; Mori, Kazuhiko

    2017-01-01

    In order to evaluate drug-induced hematotoxicity in monkey cells in vitro, colony-forming unit-granulocyte, macrophage (CFU-GM), and burst-forming unit-erythroid (BFU-E) colony assays were established using mononuclear cells in the bone marrow collected from male cynomolgus monkeys. Furthermore, the effects of doxorubicin, chloramphenicol, and linezolid on CFU-GM and BFU-E colony formation were investigated using established monkey CFU-GM and BFU-E colony assays in comparison with those on human CFU-GM and BFU-E colonies acquired from human umbilical cord blood cells. Bone marrow mononuclear cells were collected from the ischial or iliac bone of male cynomolgus monkeys. The cells were subsequently processed by density gradient separation at 1.067, 1.070, or 1.077 g/mL for CFU-GM or 1.077 g/mL for BFU-E, and then cultured in methylcellulose medium for 9 or 13 days, respectively. A sufficient number of CFU-GM colonies were formed from mononuclear cells processed at a density of 1.070 g/mL. Moreover, the number of BFU-E colonies from the cells processed at a density of 1.077 g/mL was sufficient for the colony assay. The number of CFU-GM or BFU-E colonies decreased after treatment with the drugs of interest in a concentration-dependent manner. Compared with human CFU-GM, monkey CFU-GM were more sensitive to chloramphenicol and resistant to doxorubicin, whereas monkey BFU-E were more sensitive to all compounds in comparison to the sensitivity of human BFU-E. In conclusion, monkey CFU-GM and BFU-E colony assays were established and considered useful tools to evaluate the differences in drug-induced hematotoxicity between species.

  3. Colonialism, customary law and the post-colonial state in Africa: the ...

    African Journals Online (AJOL)

    Colonialism became a fact of life in many African countries. An effect of colonialism especially in the former British colonized countries was the transplantation of the British legal system, which led to recognition of both systems and the gradual relegation of the indigenous system otherwise called customary law. The use and ...

  4. Colonial Legal Reasoning in the Post-Colonial African State: A ...

    African Journals Online (AJOL)

    Colonial Legal Reasoning in the Post-Colonial African State: A Critique and a Defense of the Argument from African Metaphysical Epistemology. ... Africa, as it has the advantageous result of helping in the search for truth concerning such offences, thereby promoting the delivery of effective legal justice, and thus contributing ...

  5. Review Essay A history of colonialism through post-colonial lenses ...

    African Journals Online (AJOL)

    Review Essay A history of colonialism through post-colonial lenses: reading Mahmood Mamdani's citizen and subject. Sanya Osha. Abstract. No Abstract. The Nigerian Journal of Economic History Vol. 2, 1999: 155-161. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  6. Colony collapse disorder: a descriptive study.

    Directory of Open Access Journals (Sweden)

    Dennis Vanengelsdorp

    Full Text Available BACKGROUND: Over the last two winters, there have been large-scale, unexplained losses of managed honey bee (Apis mellifera L. colonies in the United States. In the absence of a known cause, this syndrome was named Colony Collapse Disorder (CCD because the main trait was a rapid loss of adult worker bees. We initiated a descriptive epizootiological study in order to better characterize CCD and compare risk factor exposure between populations afflicted by and not afflicted by CCD. METHODS AND PRINCIPAL FINDINGS: Of 61 quantified variables (including adult bee physiology, pathogen loads, and pesticide levels, no single measure emerged as a most-likely cause of CCD. Bees in CCD colonies had higher pathogen loads and were co-infected with a greater number of pathogens than control populations, suggesting either an increased exposure to pathogens or a reduced resistance of bees toward pathogens. Levels of the synthetic acaricide coumaphos (used by beekeepers to control the parasitic mite Varroa destructor were higher in control colonies than CCD-affected colonies. CONCLUSIONS/SIGNIFICANCE: This is the first comprehensive survey of CCD-affected bee populations that suggests CCD involves an interaction between pathogens and other stress factors. We present evidence that this condition is contagious or the result of exposure to a common risk factor. Potentially important areas for future hypothesis-driven research, including the possible legacy effect of mite parasitism and the role of honey bee resistance to pesticides, are highlighted.

  7. Active accumulation of internal DIC pools reduces transport limitation in large colonies of Nostoc pruniforme

    DEFF Research Database (Denmark)

    Raun, Ane-Marie Løvendahl; Borum, Jens; Jensen, Kaj Sand

    2009-01-01

    Nostoc pruniforme is a freshwater cyanobacterium forming large spherical colonies of up to several centimeters in diameter. The size and shape result in low surface area to volume (SA/V) ratios that potentially put severe constraints on resource acquisition. In the present study we have specifica......Nostoc pruniforme is a freshwater cyanobacterium forming large spherical colonies of up to several centimeters in diameter. The size and shape result in low surface area to volume (SA/V) ratios that potentially put severe constraints on resource acquisition. In the present study we have...

  8. Is colonialism history? The declining impact of colonial legacies on African institutional and economic development : The declining impact of colonial legacies on African institutional and economic development

    NARCIS (Netherlands)

    Maseland, Robbert

    2018-01-01

    This paper investigates the claim that colonial history has left an enduring imprint on Africa's institutional and economic development. The literature following Acemoglu, Johnson and Robinson (2001) and Sokoloff and Engerman (2000) maintains that different types of colonialism affected the

  9. Late winter feeding stimulates rapid spring development of carniolan honey bee colonies (Apis mellifera carnica

    Directory of Open Access Journals (Sweden)

    Zlatko Puškadija

    2017-01-01

    Full Text Available Unfavourable weather conditions after the queen starts with intensive oviposition during early spring may cause an imbalance in the division of tasks among worker bees in the bee colony. This can lead to slow spring development and poor exploitation of the main spring nectar flows. In order to accelerate the spring development, it is necessary, as a technological measure, to feed supplemental candy to bee colonies. In this research, the necessity of supplemental feeding, as well as the composition of candy (pollen and protein substitute were analysed. Three groups of ten bee colonies each were formed - the control, unfed group, pollen candy fed and protein substitute candy fed. In the period from 22/02/2016 and 04/04/2016 three control measurements were performed during which the number of bees, the number of brood cells and weight of the bee colonies were determined. The research has shown that supplemental feeding of the bee colony in late winter in order to encourage the rapid spring development is justified. Namely, at the final measurements in April, the results showed differences between groups. The treated colonies had higher net hive weight, a greater number of bees and statistically significantly more brood cells. The results of this study confirm that the technological measure of supplemental feeding in late winter should be performed on all commercial apiaries for the production of honey, pollen, royal jelly, queen bees and bee venom.

  10. Colony size evolution and the origin of eusociality in corbiculate bees (Hymenoptera: Apinae.

    Directory of Open Access Journals (Sweden)

    Enrique Rodriguez-Serrano

    Full Text Available Recently, it has been proposed that the one of the main determinants of complex societies in Hymenoptera is colony size, since the existence of large colonies reduces the direct reproductive success of an average individual, given a decreased chance of being part of the reproductive caste. In this study, we evaluate colony size evolution in corbiculate bees and their relationship with the sociality level shown by these bees. Specifically i the correlation between colony size and level of sociality considering the phylogenetic relationship to evaluate a general evolutionary tendency, and ii the hypothetical ancestral forms of several clades within a phylogeny of corbiculate bees, to address idiosyncratic process occurring at important nodes. We found that the level of social complexity in corbiculate bees is phylogenetically correlated with colony size. Additionally, another process is invoked to propose why colony size evolved concurrently with the level of social complexity. The study of this trait improves the understanding of the evolutionary transition from simple to complex societies, and highlights the importance of explicit probabilistic models to test the evolution of other important characters involved in the origin of eusociality.

  11. Thymidine kinase deficient human cells have increased UV sensitivity in their capacity to support herpes simplex virus but normal UV sensitivity for colony formation

    International Nuclear Information System (INIS)

    Rainbow, A.J.

    1989-01-01

    A thymidine kinase deficient (tk - ) and two thymidine kinase proficient (tk + ) human cell lines were compared for UV sensitivity using colony-forming ability as well as their capacity to support the plaque formation of herpes simplex type 1 (HSV-1).The tk - line (143 cells) was a derivative of one of the tk + lines (R970-5), whereas the other tk + line (AC4 cells) was a derivative of the 143 cells obtained by transfection with purified sheared HSV-2 DNA encoding the viral tk gene. 143, R970-5 and AC4 cells showed a similar UV sensitivity for colony-forming ability. In contrast, the capacity to support HSV-1 plaque formation immediately (within 1 h) afte UV-irradiation was reduced to a greater extent in the 143 cells compared to the R970-5 and AC4 cells. Capacity curves for plaque formation of the HSV-1: KOS wild-type (tk + ) strain were similar to those for the HSV-1: PTK3B mutant (tk - ) strain were similar to those for the HSV-1: PTK3B mutant (tk - ) strain in the 3 cell strains, indicating that the viral tk gene does not influence the ability of HSV-1 to form plaques in UV-irradiated compared to unirradiated human cells. Cellular capacity for HSV-1 plaque formation was found to recover in both tk - and tk + cells for cultures infected 24 h after UV-irradiation. These results suggest that repair of UV-damaged DNA takes place to a similar extent in both tk - and tk + human cells, but the kinetics of repair are initially slower in tk - compared to tk + human cells. (author). 33 refs.; 3 figs.; 1 tab

  12. Targeted removal of ant colonies in ecological experiments, using hot water.

    Science.gov (United States)

    Tschinkel, Walter R; King, Joshua R

    2007-01-01

    Ecological experiments on fire ants cannot, or should not, use poison baits to eliminate the fire ants because such baits are not specific to fire ants, or even to ants. Hot water is an extremely effective and specific killing agent for fire ant colonies, but producing large amounts of hot water in the field, and making the production apparatus mobile have been problematical. The construction and use of a charcoal-fired kiln made from a 55-gal. oil drum lined with a sand-fireclay mixture is described. An automobile heater fan powered from a 12-v battery provided a draft. Dual bilge pumps pumped water from a large tank through a long coil of copper tubing within the kiln to produce 4 to 5 l. of hot water per min. The hot water was collected in 20 l. buckets and poured into fire ant nests previously opened by piercing with a stick. The entire assembly was transported in and operated from the back of a pickup truck. Five experimental plots containing 32 to 38 colonies of the fire ant, Solenopsis invicta, Buren (Hymenoptera: Formicidae), were treated with hot water over a period of two years. All colonies on the treatment plots were treated twice with hot water early in 2004, reducing their numbers to zero. However new colonies were formed, and mature colonies expanded into the plots. A third treatment was made in the spring of 2005, after which fire ant populations were suppressed for over a year. Whereas the 5 control plots contained a total of 166 mostly large colonies, the 5 treatment plots contained no live colonies at all. Averaged over a two-year period, a 70% reduction in total number of colonies was achieved (P ants.

  13. Abyssal fiction: common shares, colonial cleavages

    Directory of Open Access Journals (Sweden)

    Alexandre Montaury

    2016-12-01

    Full Text Available The paper aims to develop a reflection on the interaction between the legacies of colonialism and traditional symbolic and cultural practices in African Portuguese-speaking spaces. From a preliminary analysis of fictional texts of wide circulation in Brazil, aims to examine the cleavages, or “abyssal lines” that constitute experiences printed in the daily life of the former Portuguese colony of Cape Verde, Mozambique and Angola.---DOI: http://dx.doi.org/10.21881/abriluff.2016n17a378

  14. Political caricatures in colonial Egypt

    DEFF Research Database (Denmark)

    Awad, Sarah H.

    2018-01-01

    embodied in those images in relation to the newly defined nation. The lens of social and cultural psychology is used to understand the politics of those images in visually constructing national identity, positioning different social actors in the social and political context, and feeding into an enduring......Images represent in one form or another the perceived reality of a time. The image projects this perception into the world where receiving audiences are invited to reflect upon it and react to it. This paper looks at images of political caricatures published between the years of 1926 and 1931...... in two Egyptian newspapers: Al-Kashkūl and Al-Siyāsa al-Usbu‘iyya. This marks a unique time in Egyptian national discourse, as it was then on the road towards securing complete political independence from British occupation. The visual analysis of the 322 caricatures aims to interpret the meanings...

  15. Colonies of Gyrosigma eximium: a new phenomenon in Arctic tidal flats

    Directory of Open Access Journals (Sweden)

    Józef Wiktor

    2016-10-01

    Full Text Available For the first time at Svalbard, a colonial form of the tube-dwelling diatom Gyrosigma eximium was found in summer 2010 in the tidal flats on Spitsbergen at 78°N. The colonies take the form of conical, green structures that are 1–2 cm high and are associated with other diatom taxa and cyanobacteria (Oscillatoriaceae. The diatom colonies were associated with rich meiofauna and apparently act as cohesive factors for the fine sediment. In the Arctic tidal flats, this represents the first observation of long-term sediment stabilization and biological enrichment. Since this first observation, this species has apparently colonized broader areas in Advenentelva's tidal flat.

  16. Genetic component in learning ability in bees.

    Science.gov (United States)

    Kerr, W E; Moura Duarte, F A; Oliveira, R S

    1975-10-01

    Twenty-five bees, five from each of five hives, were trained to collect food at a table. When the bee reached the table, time was recorded for 12 visits. Then a blue and yellow pan was substituted for the original metal pan, and time and correct responses were recorded for 30 trips (discrimination phase). Finally, food was taken from the pan and extinction was recorded as incorrect responses for 20 visits. Variance analysis was carried out, and genetic variance was undetected for discrimination, but was detected for extinction. It is concluded that learning is very important for bees, so that any impairment in such ability affects colony survival.

  17. The politics of gender and medicine in colonial India: the Countess of Dufferin's Fund, 1885-1888.

    Science.gov (United States)

    Lal, M

    1994-01-01

    This article examines the relationship of gender issues and the practice of medicine in the context of colonialism as revealed through an analysis of the Dufferin Fund in India. Early private efforts to deliver Western health care in India were confined to combatting disease among the military and to the work of a few missionaries. The Dufferin Fund was created by Queen Victoria to provide health services to Indian women by training women physicians and personnel, establishing medical facilities, and providing female nurses and midwives. Fund-raising subscriptions were largely supported by wealthy Indians. British perceptions about Indian society and the nature of colonial rule were reflected by the Fund which responded to the misguided notion that Indian women would only accept the services of female physicians. In contrast with British officialdom, however, the Fund accepted the existence of purdah although the multifaceted nature of this social institution was ignored or misunderstood. These positions buttressed arguments to promote the medical training of English women (who would be shipped out of the way to India). The positions also assigned blame for the poor condition of Indian women to Indian men who were, nonetheless, expected to support the work of the Fund. British opposition to traditional forms of medicine were evident by the Fund's vociferous criticisms of Indian midwives. The Fund was criticized in turn for relying on trained Western women instead of training native women. When Lord Dufferin's stint as Viceroy was over, praise was lavished upon the departing Lady Dufferin as a proxy used by the Indian press for expressing a desire for a more humanitarian style of colonial rule. From the colonial point of view, Lady Dufferin set an example for the good works of the future vicereines. However, any accomplishments of the Fund were adopted by the imperial government as its own, and insufficient funding and inactivity led to a loss in the Fund's ability

  18. Project Final Report: HPC-Colony II

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Terry R [ORNL; Kale, Laxmikant V [University of Illinois, Urbana-Champaign; Moreira, Jose [IBM T. J. Watson Research Center

    2013-11-01

    This report recounts the HPC Colony II Project which was a computer science effort funded by DOE's Advanced Scientific Computing Research office. The project included researchers from ORNL, IBM, and the University of Illinois at Urbana-Champaign. The topic of the effort was adaptive system software for extreme scale parallel machines. A description of findings is included.

  19. English Literatures in Post-Colonial Singapore

    Science.gov (United States)

    Dass, Rozita

    2015-01-01

    The emergence of a vibrant literary, culture and arts scene promotes Singapore's claims as a hub for arts and culture in the Asian region, and as a global arts city by the 21st century. The richness and variety of Singapore literature from the early post-colonial years are evident in the evolution of a Singapore literary culture. The diaspora of…

  20. Latin America: Essays Interpretating Colonial Legacy

    Directory of Open Access Journals (Sweden)

    María Pia López

    2013-12-01

    Full Text Available A large part of the Latin–American literature of the 19th and 20th century tried to deal with the national question intertwining different dimensions: the weight of colonial legacy, the cultural peculiarity of the nation and the inner relations between social classes and ethnic groups. Thinking the nation implied, in any case, to think the difference and the conflict with others, as well as the inner conflict and the logic of local colonialism. Analyzing some of these essays that played a central role in such process of recasting the origin of the nation, the author moves around three main axes: the formulation of dualist writings (colonial/national; white /indigenous; civilization/wilderness, the issue of language (the language inherited from the colonial experience versus the multilingual nature of indigenous Latin American societies, and the hypothesis about the birth of the nation – appointed to different groups – and its normal functioning as legitimization of the order sprung from independences.

  1. Teaching the History of Colonial Peru.

    Science.gov (United States)

    Campbell, Leon G.

    1981-01-01

    Presents a bibliographic review essay on the topic of colonial Peru organized according to the following topics: Pre-Columbian Peru, 5500 B.C.- 1532; the conquest of Peru, 1532-1572; Peru under the Hapsburgs, 1516-1700; Bourbon Peru, 1700-1808; and the coming of independence, 1808-1821. The essay is based on a bibliography composed largely of…

  2. PRE-COLONIAL TRANSPORT SYSTEMS: A VERITABLE ...

    African Journals Online (AJOL)

    FBL

    ideas between places and over-time and mediate relationship and interactions between individuals and ... International Journal of Development and Management Review (INJODEMAR) Vol. 9, No 1 ..... Colonial Times, “Ahiajoku Lecture Series, Owerri: Ministry of Information, Youth and Sports Government Press. Afigbo A.E ...

  3. Policing native pleasures: a colonial history.

    Science.gov (United States)

    Jabbar, Naheem

    2012-12-01

    The moral modality of colonial power is still with us when it comes to the recreation of sexual norms of traditional or feudal society. We can examine the emergent properties of colonial knowledge anew by exploring how the colonial regime's strategic attention of regulating brothels in India differed from the analytic of power Foucault described for sexuality in European society. It turns out that amongst other things, public anxieties about the failure of adaptation by South Asians are incapable of leaving sexuality aside as a key interpretive device for their culture. The British preoccupation with reproducing the dynamics of the bourgeois matrimonial market on foreign soil in the mid-nineteenth century similarly necessitated a sociological pretext for racial purity. However, the kind of knowledge a typical traveller and employee of the East India Company brought to the Victorian public from his own researches in the brothels and streets of colonial India, which revealed how popular prostitution was as a vice amongst the officer class, was also more than a welcome imaginary relief from Christian morality; it was an alternative vision of modernity. © London School of Economics and Political Science 2012.

  4. Hyphal growth and colony expansion (Forum Commentary)

    NARCIS (Netherlands)

    Bruggen, van A.H.C.; Termorshuizen, A.J.; Semenov, A.M.

    2000-01-01

    Bailey et al. have used a quite simple but elegant experimental method and developed innovative concepts about phase transitions in colony behavior based on non-linearity of invasion probability with distance between substrate particles. This proves again the old adage that significant scientific

  5. 128 COLONIALISM: NEXUS FOR MYRIAD RELIGIOUS ...

    African Journals Online (AJOL)

    In recent times, the version of Christians we have, who also practice ATR is ... Colonialism is not a new concept in the history of Africa. .... of their kits and kin still living. ..... believe that God could be reached through different media. ..... Hornby, A.S., (2006), Oxford Advanced Learner's Dictionary of Current English, New York,.

  6. Buckling instability in ordered bacterial colonies

    Science.gov (United States)

    Boyer, Denis; Mather, William; Mondragón-Palomino, Octavio; Orozco-Fuentes, Sirio; Danino, Tal; Hasty, Jeff; Tsimring, Lev S.

    2011-04-01

    Bacterial colonies often exhibit complex spatio-temporal organization. This collective behavior is affected by a multitude of factors ranging from the properties of individual cells (shape, motility, membrane structure) to chemotaxis and other means of cell-cell communication. One of the important but often overlooked mechanisms of spatio-temporal organization is direct mechanical contact among cells in dense colonies such as biofilms. While in natural habitats all these different mechanisms and factors act in concert, one can use laboratory cell cultures to study certain mechanisms in isolation. Recent work demonstrated that growth and ensuing expansion flow of rod-like bacteria Escherichia coli in confined environments leads to orientation of cells along the flow direction and thus to ordering of cells. However, the cell orientational ordering remained imperfect. In this paper we study one mechanism responsible for the persistence of disorder in growing cell populations. We demonstrate experimentally that a growing colony of nematically ordered cells is prone to the buckling instability. Our theoretical analysis and discrete-element simulations suggest that the nature of this instability is related to the anisotropy of the stress tensor in the ordered cell colony.

  7. Buckling instability in ordered bacterial colonies

    International Nuclear Information System (INIS)

    Boyer, Denis; Mather, William; Mondragón-Palomino, Octavio; Danino, Tal; Hasty, Jeff; Orozco-Fuentes, Sirio; Tsimring, Lev S

    2011-01-01

    Bacterial colonies often exhibit complex spatio-temporal organization. This collective behavior is affected by a multitude of factors ranging from the properties of individual cells (shape, motility, membrane structure) to chemotaxis and other means of cell–cell communication. One of the important but often overlooked mechanisms of spatio-temporal organization is direct mechanical contact among cells in dense colonies such as biofilms. While in natural habitats all these different mechanisms and factors act in concert, one can use laboratory cell cultures to study certain mechanisms in isolation. Recent work demonstrated that growth and ensuing expansion flow of rod-like bacteria Escherichia coli in confined environments leads to orientation of cells along the flow direction and thus to ordering of cells. However, the cell orientational ordering remained imperfect. In this paper we study one mechanism responsible for the persistence of disorder in growing cell populations. We demonstrate experimentally that a growing colony of nematically ordered cells is prone to the buckling instability. Our theoretical analysis and discrete-element simulations suggest that the nature of this instability is related to the anisotropy of the stress tensor in the ordered cell colony

  8. A catalog of Louisiana's nesting seabird colonies

    Science.gov (United States)

    Fontenot, William R.; Cardiff, Steve W.; DeMay, Richard A.; Dittmann, Donna L.; Hartley, Stephen B.; Jeske, Clinton W.; Lorenz, Nicole; Michot, Thomas C.; Purrington, Robert Dan; Seymour, Michael; Vermillion, William G.

    2012-01-01

    Summarizing his colonial nesting waterbird survey experiences along the northern coast of the Gulf of Mexico in a paper presented to the Colonial Waterbird Group of the Waterbird Society (Portnoy 1978), bird biologist John W. Portnoy stated, “This huge concentration of nesting waterbirds, restricted almost entirely to the wetlands and estuaries of southern Louisiana, is unmatched in all of North America; for example, a 1975 inventory of wading birds along the Atlantic Coast from Maine to Florida [Custer and Osborn, in press], tallied 250,000 breeding [waterbirds] of 14 species, in contrast with the 650,000 birds of 15 species just from Sabine Pass to Mobile Bay.” The “650,000 birds” to which Portnoy referred, were tallied by him in a 1976 survey of coastal Louisiana, Mississippi, and Alabama (see below, under “Major Surveys” section). According to the National Atlas of Coastal Waterbird Colonies in the Contiguous United States: 1976-82 (Spendelow and Patton 1988), the percentages of the total U.S. populations of Laughing Gull (11%), Forster's Tern (52%), Royal Tern (16%), Sandwich Tern (77%), and Black Skimmer (44%) which annually nest in Louisiana are significant – perhaps crucially so in the cases of Forster's Tern, Sandwich Tern, and Black Skimmer. Nearly three decades after Spendelow and Patton's determinations above, coastal Louisiana still stands out as the major center of colonial wading bird and seabird nesting in all of the United States. Within those three intervening decades, however, the

  9. 178 MULTIPLE COLONIALISM IN WESTERN SAHARA Macharia ...

    African Journals Online (AJOL)

    Administrator

    Civil War, the colony had also been a possible bargaining chip with Adolph Hitler when ... Morocco gave rise to an Army of Liberation that inspired the Sahrawi to fight ..... or defense, matters, and promised the Sahrawi the right to vote for their ...

  10. In vitro biofilm forming capacity on abiotic contact surfaces by outbreak-associated Vibrio harveyi strains

    Directory of Open Access Journals (Sweden)

    Pallaval Veera Bramha Chari

    2014-02-01

    Full Text Available Objective: To evaluate the in vitro biofilm forming capacity on abiotic food contact surfaces by Vibrio harveyi (V. harveyi strains. Methods: Thirty six Gram-negative V. harveyi strains were isolated from various street vended seafood outlets in a food processing line and evaluated for their ability to produce mucoid biofilms on food contact surfaces using a microplate assay. Phenotypic characterization of mucoid biofilm producing V. harveyi strains were screened on Congo red agar, thiosulfate-citrate-bile salts-sucrose agar and tryptic soy agar, respectively. Results: Only five V. harveyi strains (14% were mucoid biofilm producers characterized by formation of black colonies, whereas the remaining 31 strains (86% were not capable of producing biofilm characterized by formation of red colonies or pinkish-red colonies with darkening at the centre. The morphological, physiological and biochemical characteristics of these isolates were studied using standard protocols. Strain identification was confirmed by polymerase chain reaction targeted to species-specific polymerase chain reaction primers VH-1 and VH-2 corresponding to variable regions of V. harveyi 16S rRNA sequence. All the biofilm-forming strains showed resistance to at least three antimicrobial compounds tested. V. harveyi strains isolated from various seafood were able to form biofilms of different capacity, and the strains VB267, VB238 and VB166 isolated from cat fish, shrimp and eel fish exhibited significantly greater biofilm forming ability compared to other isolates. Conclusions: It can be concluded from the present study that the strain VB166 was able to better attach and form subsequent biofilms on glass and stainless steel compared to high density polyethylene. These properties allow these bacteria to survive, proliferate and persist in street vended seafood outlets.

  11. Evolution of life cycle, colony morphology, and host specificity in the family Hydractiniidae (Hydrozoa, Cnidaria).

    Science.gov (United States)

    Miglietta, Maria Pia; Cunningham, Clifford W

    2012-12-01

    Biased transitions are common throughout the tree of life. The class hydrozoa is no exception, having lost the feeding medusa stage at least 70 times. The family hydractiniidae includes one lineage with pelagic medusae (Podocoryna) and several without (e.g., Hydractinia). The benthic colony stage also varies widely in host specificity and in colony form. The five-gene phylogeny presented here requires multiple transitions between character states for medusae, host specificity, and colony phenotype. Significant phylogenetic correlations exist between medusoid form, colony morphology, and host specificity. Species with nonfeeding medusae are usually specialized on a single host type, and reticulate colonies are correlated with nonmotile hosts. The history of feeding medusae is less certain. Podocoryna is nested within five lineages lacking medusae. This requires either repeated losses of medusae, or the remarkable re-evolution of a feeding medusa after at least 150 million years. Traditional ancestral reconstruction favors medusa regain, but a likelihood framework testing biased transitions cannot distinguish between multiple losses versus regain. A hypothesis of multiple losses of feeding medusae requires transient selection pressure favoring such a loss. Populations of species with feeding medusae are always locally rare and lack of feeding medusae does not result in restricted species distribution around the world. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

  12. Improved artificial bee colony algorithm based gravity matching navigation method.

    Science.gov (United States)

    Gao, Wei; Zhao, Bo; Zhou, Guang Tao; Wang, Qiu Ying; Yu, Chun Yang

    2014-07-18

    Gravity matching navigation algorithm is one of the key technologies for gravity aided inertial navigation systems. With the development of intelligent algorithms, the powerful search ability of the Artificial Bee Colony (ABC) algorithm makes it possible to be applied to the gravity matching navigation field. However, existing search mechanisms of basic ABC algorithms cannot meet the need for high accuracy in gravity aided navigation. Firstly, proper modifications are proposed to improve the performance of the basic ABC algorithm. Secondly, a new search mechanism is presented in this paper which is based on an improved ABC algorithm using external speed information. At last, modified Hausdorff distance is introduced to screen the possible matching results. Both simulations and ocean experiments verify the feasibility of the method, and results show that the matching rate of the method is high enough to obtain a precise matching position.

  13. A Multistrategy Optimization Improved Artificial Bee Colony Algorithm

    Directory of Open Access Journals (Sweden)

    Wen Liu

    2014-01-01

    Full Text Available Being prone to the shortcomings of premature and slow convergence rate of artificial bee colony algorithm, an improved algorithm was proposed. Chaotic reverse learning strategies were used to initialize swarm in order to improve the global search ability of the algorithm and keep the diversity of the algorithm; the similarity degree of individuals of the population was used to characterize the diversity of population; population diversity measure was set as an indicator to dynamically and adaptively adjust the nectar position; the premature and local convergence were avoided effectively; dual population search mechanism was introduced to the search stage of algorithm; the parallel search of dual population considerably improved the convergence rate. Through simulation experiments of 10 standard testing functions and compared with other algorithms, the results showed that the improved algorithm had faster convergence rate and the capacity of jumping out of local optimum faster.

  14. Multiple depots vehicle routing based on the ant colony with the genetic algorithm

    Directory of Open Access Journals (Sweden)

    ChunYing Liu

    2013-09-01

    Full Text Available Purpose: the distribution routing plans of multi-depots vehicle scheduling problem will increase exponentially along with the adding of customers. So, it becomes an important studying trend to solve the vehicle scheduling problem with heuristic algorithm. On the basis of building the model of multi-depots vehicle scheduling problem, in order to improve the efficiency of the multiple depots vehicle routing, the paper puts forward a fusion algorithm on multiple depots vehicle routing based on the ant colony algorithm with genetic algorithm. Design/methodology/approach: to achieve this objective, the genetic algorithm optimizes the parameters of the ant colony algorithm. The fusion algorithm on multiple depots vehicle based on the ant colony algorithm with genetic algorithm is proposed. Findings: simulation experiment indicates that the result of the fusion algorithm is more excellent than the other algorithm, and the improved algorithm has better convergence effective and global ability. Research limitations/implications: in this research, there are some assumption that might affect the accuracy of the model such as the pheromone volatile factor, heuristic factor in each period, and the selected multiple depots. These assumptions can be relaxed in future work. Originality/value: In this research, a new method for the multiple depots vehicle routing is proposed. The fusion algorithm eliminate the influence of the selected parameter by optimizing the heuristic factor, evaporation factor, initial pheromone distribute, and have the strong global searching ability. The Ant Colony algorithm imports cross operator and mutation operator for operating the first best solution and the second best solution in every iteration, and reserves the best solution. The cross and mutation operator extend the solution space and improve the convergence effective and the global ability. This research shows that considering both the ant colony and genetic algorithm

  15. Long-active granulocyte colony-stimulating factor for peripheral blood hematopoietic progenitor cell mobilization.

    Science.gov (United States)

    Martino, Massimo; Laszlo, Daniele; Lanza, Francesco

    2014-06-01

    Peg-filgrastim (PEG-FIL), a polyethylene glycol-conjugated form of granulocyte colony-stimulating factor (G-CSF), has been introduced in clinical practice and is effective in shortening the time of neutropenia after cytotoxic chemotherapy. G-CSF has emerged as the preferred cytokine for hematopoietic progenitor cells' (HPC) mobilization. Nevertheless, data on the ability of PEG-FIL in this field have been published. We review publications in the field with the goal of providing an overview of this approach. PEG-FIL may be able to mobilize CD34(+) cells in a more timely fashion than G-CSF, with the advantages of only a single-dose administration, an earlier start and a reduction in the number of apheresis procedures. The main controversies concern the dosage of the drug and the optimal dose. In the context of chemo-mobilization, a single dose of 6 mg PEG-FIL seems effective in terms of HPC's mobilization and there is no increase in this effect if the dose is doubled to 12 mg. Steady-state mobilization requires higher doses of PEG-FIL and this approach is not cost-effective when compared with G-CSF. The experiences with PEG-FIL in the healthy donor setting are very limited.

  16. An ant colony based resilience approach to cascading failures in cluster supply network

    Science.gov (United States)

    Wang, Yingcong; Xiao, Renbin

    2016-11-01

    Cluster supply chain network is a typical complex network and easily suffers cascading failures under disruption events, which is caused by the under-load of enterprises. Improving network resilience can increase the ability of recovery from cascading failures. Social resilience is found in ant colony and comes from ant's spatial fidelity zones (SFZ). Starting from the under-load failures, this paper proposes a resilience method to cascading failures in cluster supply chain network by leveraging on social resilience of ant colony. First, the mapping between ant colony SFZ and cluster supply chain network SFZ is presented. Second, a new cascading model for cluster supply chain network is constructed based on under-load failures. Then, the SFZ-based resilience method and index to cascading failures are developed according to ant colony's social resilience. Finally, a numerical simulation and a case study are used to verify the validity of the cascading model and the resilience method. Experimental results show that, the cluster supply chain network becomes resilient to cascading failures under the SFZ-based resilience method, and the cluster supply chain network resilience can be enhanced by improving the ability of enterprises to recover and adjust.

  17. Colonial Army Formats in Africa and Post-Colonial Military Coups:

    African Journals Online (AJOL)

    BSOS USER

    The centralised and autocratic features of Caliphate rule were .... latter's participation in the affairs of their respective societies, and leadership ..... deployment of the army by the NPC for internal colonial-style repression duties in the Middle Belt ...

  18. PENETRATION OF COLONIAL CULTURES IN INDONESIAN HISTORY TEXT BOOKS OF CLASS XI

    Directory of Open Access Journals (Sweden)

    Faidin Faidin

    2017-06-01

    Full Text Available This paper is commenced by the writing of study background that essentially explains the identity of the author of the Indonesian History Book, Wardaya. Then, it strives to identify the problems contained in the book. As a result, the word penetration is then chosen as the title. Specifically, penetration is a form of mixing between two different cultures either in good or hasty spheres. Correspondingly, the problem under study is on how is the form of penetration contained in textbooks, on special materials pertaining to the Dutch colonialism to Japan one. They ways they entered Indonesia, the system of government, economy, social politics, and religion were analyzed in the form of penetration in all forms of influence. The theory used in this study was the theory of diffusion that explained also the unification of culture. Therefore, the method used as the support to the writing process is a discourse analysis method developed by Hamad. This theory attempted to see and observe the discourses contained in history textbooks. Therefore, the result of this analysis was in a form of penetration implemented by the Dutch colonial in the fields of culture both in the context of the cultural element and in the context of the livelihoods. This form of penetration in this case was found in the economic field. Moreover, the field of economy can be seen in the colonial trade system. With respect to religions, it more concerned on the way a religion was introduced under Dutch colonialism. Therefore, there was a form of penetration of the influence of Dutch religious values on Indonesian society.  In regard to the politics, a system of government necessarily forced the native people to obey the colonial government, and in the same time, the rules were made by the colonial. As a result, Indonesian society that has no certain rules were forced to follow the colonial rules such as, in terms of trade, finance, taxation, rent of land. Those aforesaid facts

  19. The occurrence of the cold-water coral Lophelia pertusa (Scleractinia) on oil and gas platforms in the North Sea: Colony growth recruitment and environmental controls on distribution

    Energy Technology Data Exchange (ETDEWEB)

    Gass, S.E.; Roberts, J.M. [Scottish Association for Marine Science, Dunstaffnage Marine Laboratory, Oban, Argyll (United Kingdom)

    2006-05-15

    This study reports a newly established sub-population of Lophelia pertusa, the dominant reef-framework forming coral species in the north-east Atlantic, on oil and gas platforms in the northern North Sea. L. pertusa was positively identified on 13 of 14 platforms examined using existing oil and gas industry visual inspections. Two platforms were inspected in more detail to examine depth and colony size distributions. We recorded 947 colonies occurring between 59 and 132 m depth that coincides with cold Atlantic water at depths below the summer thermocline in the northern North Sea. We suggest that these colonies provide evidence for a planktonic larval stage of L. pertusa with recruits initially originating from populations in the north-east Atlantic and now self recruiting to the platforms. Size class distribution showed a continuous range of size classes, but with few outlying large colonies. The break between the largest colonies and the rest of the population is considered as the point when colonies began self recruiting to the platforms, resulting in greater colonization success. We present the first documented in situ colony growth rate estimate (26 {+-} 5 mm yr{sup -1}) for L. pertusa based on 15 colonies from the Tern Alpha platform with evidence for yearly recruitment events starting the year the platform was installed. Evidence of contamination from drill muds and cuttings was observed on the Heather platform but appeared limited to regions close to drilling discharge points, where colonies experience partial as well as whole colony mortality. (author)

  20. JAX Colony Management System (JCMS): an extensible colony and phenotype data management system

    OpenAIRE

    Donnelly, Chuck J.; McFarland, Mike; Ames, Abigail; Sundberg, Beth; Springer, Dave; Blauth, Peter; Bult, Carol J.

    2010-01-01

    The Jackson Laboratory Colony Management System (JCMS) is a software application for managing data and information related to research mouse colonies, associated biospecimens, and experimental protocols. JCMS runs directly on computers that run one of the PC Windows® operating systems, but can be accessed via web browser interfaces from any computer running a Windows, Macintosh®, or Linux® operating system. JCMS can be configured for a single user or multiple users in small- to medium-size wo...

  1. Queen Quality and the Impact of Honey Bee Diseases on Queen Health: Potential for Interactions between Two Major Threats to Colony Health

    Directory of Open Access Journals (Sweden)

    Esmaeil Amiri

    2017-05-01

    Full Text Available Western honey bees, Apis mellifera, live in highly eusocial colonies that are each typically headed by a single queen. The queen is the sole reproductive female in a healthy colony, and because long-term colony survival depends on her ability to produce a large number of offspring, queen health is essential for colony success. Honey bees have recently been experiencing considerable declines in colony health. Among a number of biotic and abiotic factors known to impact colony health, disease and queen failure are repeatedly reported as important factors underlying colony losses. Surprisingly, there are relatively few studies on the relationship and interaction between honey bee diseases and queen quality. It is critical to understand the negative impacts of pests and pathogens on queen health, how queen problems might enable disease, and how both factors influence colony health. Here, we review the current literature on queen reproductive potential and the impacts of honey bee parasites and pathogens on queens. We conclude by highlighting gaps in our knowledge on the combination of disease and queen failure to provide a perspective and prioritize further research to mitigate disease, improve queen quality, and ensure colony health.

  2. Radiosensitivity of mice and its modifiers based on the endogeneous spleen colony formation

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Jindo; Wagatuma, Kaoru

    1987-02-01

    In irradiated mouse hematopoietic tissue, there is a group of cells which can proliferate and form macroscopic colonies. In the spleen, the colonies formed in this manner are discrete and easy to count. In order to look into a difference of radiosensitivity between male and female and the mechanisms of the modification, such as protective agent and hormones on radiosensitivity, the spleen colony forming (SCF) is used as an indicator of reactions in the x-rays irradiated mice. A linear decrease was found in SCF depended on x-rays dose. From the colony forming after irradiation the male was more radiosensitive than female. AET protected from the injury depended on the radiation dose in male mice, but in female mice, protection effects were not observed. Gonatropin showed protective effects for radiation injury on high dose irradiation both in male and female mice. Adrenaline showed similar effects as Gonatropin. Insuline showed a negative effects of protection on 400 R irradiation, while on 600 R irradiation, protective effects were observed.

  3. "Shooting Back" in the Occupied Territories: An Anti-Colonial Participatory Politics

    Science.gov (United States)

    Desai, Chandni

    2015-01-01

    In this article I argue that Palestinians, in particular Palestinian youth engage in forms of cultural resistance such as filming, video production and dissemination in their everyday lives as a way to re-configure place, space, law, knowledge and violence, through a critical race, feminist, anti-colonial theoretical analysis. Recently, interest…

  4. Eboh and Traditional Medicine in Pre-Colonial Apana Social Systems

    African Journals Online (AJOL)

    The paper extols the significance of traditional medicine in the social systems of pre-colonial Apana. Traditional medicine and its practitioners maintained their popularity in the socio-cultural development of Apana. The Apana word, eboh, which exists in the plural form, refers to the practitioners of traditional medicine.

  5. Resisting Exile in the "Land of the Free:" Indigenous Groundwork at Colonial Intersections

    Science.gov (United States)

    Clark, D. Anthony Tyeeme; Powell, Malea

    2008-01-01

    The guest editorialists argue in this introduction that the phrase "indigenous groundwork at colonial intersections" identifies versatile cultural, historical, and social processes that fundamentally--at times devastatingly--shape relations among differently situated life forms on this planet. In short, Indigenous groundwork marks Indigenous…

  6. Colony formation in agar: in vitro assay for haemopoietic stem cells

    NARCIS (Netherlands)

    Dicke, K.A.; Platenburg, M.G.C.; Bekkum, D.W. van

    1971-01-01

    Using a method in which embryo fibroblasts were used as feeder layers, the colony forming capacity in agar of a variety of mouse haemopoietic suspensions was compared with their CFUs content. A striking parallelism between the results of the two assays was found. In addition, under certain

  7. Colony size, cell number, carbon and nitrogen contents of Phaeocystis pouchetii from western Norway

    NARCIS (Netherlands)

    Verity, Peter G.; Whipple, S. J.; Nejstgaard, J. C.; Alderkamp, A.-C.

    Phaeocystis pouchetii is an ecologically important colony-forming marine phytoplankton species in northern hemisphere cold waters. It plays a central role in the processing of biogeochemically important elements in the upper ocean during spring blooms. Here, we report highly significant quantitative

  8. Co-occurrence of mated workers and a mated queen in a colony of ...

    African Journals Online (AJOL)

    arnoldi (Hymenoptera: Formicidae). Martin Villet *. Department of Zoology, University of the Witwatersrand, P.O.. Wits, 2050 Republic of South Africa. Received 23 March 1992; accepted 8 June 1992. A colony of Platythyrea arnold; was found to contain a functional queen and laying workers, both virgin and mated. This form ...

  9. 21 CFR 866.2180 - Manual colony counter.

    Science.gov (United States)

    2010-04-01

    ...) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2180 Manual colony counter. (a) Identification. A manual colony counter is a device intended for medical purposes that consists...

  10. Hybrid Bee Ant Colony Algorithm for Effective Load Balancing And ...

    African Journals Online (AJOL)

    PROF. OLIVER OSUAGWA

    Ant Colony algorithm is used in this hybrid Bee Ant Colony algorithm to solve load balancing issues ... Genetic Algorithm (MO-GA) for dynamic job scheduling that .... Information Networking and Applications Workshops. [7]. M. Dorigo & T.

  11. Conflict and conflict resolution in Africa: Engaging the colonial factor

    African Journals Online (AJOL)

    maintaining colonial-style approaches to African conflicts at the expense of a ... Educational Leadership at the College of Education and Human Services, University of .... Colonial rule was the antithesis of democracy, because it was premised.

  12. Honeybee colony marketing and its implications for queen rearing ...

    African Journals Online (AJOL)

    Honeybee colony marketing and its implications for queen rearing and beekeeping development in Werieleke ... Thus, colony marketing is an important venture in Werieleke district of Tigray region. ... EMAIL FULL TEXT EMAIL FULL TEXT

  13. Growth pattern of the surface of fungus Aspergillus colony

    Science.gov (United States)

    Matsuura, Shu; Miyazima, Sasuke

    1992-05-01

    Aspergillus oryzae colonies were grown under various glucose concentrations, temperatures, and agar concentrations, and the effects on the pattern were investigated. Patterns of colony were found to vary from uniform to diffusion-limited aggregation type.

  14. Readability and Reading Ability.

    Science.gov (United States)

    Wright, Benjamin D.; Stenner, A. Jackson

    This document discusses the measurement of reading ability and the readability of books by application of the Lexile framework. It begins by stating the importance of uniform measures. It then discusses the history of reading ability testing, based on the assumption that no researcher has been able to measure more than one kind of reading ability.…

  15. Isolation of hemopoietic stem cell subsets from murine bone marrow: II. Evidence for an early precursor of day-12 CFU-S and cells associated with radioprotective ability

    International Nuclear Information System (INIS)

    Ploemacher, R.E.; Brons, N.H.

    1988-01-01

    Counterflow centrifugal elutriation (CCE) in combination with plastic adherence and fluorescence-activated cell sorting were used consecutively to enrich functionally different subpopulations of pluripotent hemopoietic stem cells (HSC) from mouse bone marrow. The nonadherent CCE fractions were labeled with wheat germ agglutinin (WGA)-fluorescein isothiocyanate (FITC) and sorted according to differences in fluorescence within various windows on the basis of forward (FLS) and perpendicular (PLS) light scatter. The sorted cells were then assayed for their (1) in vivo colony-forming ability (day-7 and day-12 spleen colony-forming units [CFU-S]), (2) radioprotective ability (RPA; 30-day survival), and (3) their ability to repopulate the bone marrow or spleen over a 13-day period with day-12 CFU-S, granulocyte-macrophage colony-forming units (CFU-GM), nucleated cells, or cells associated with RPA. The highest incidence of day-12 CFU-S and cells with RPA was obtained by sorting the most WGA-positive cells with relatively high PLS (enrichment, 50- to 200-fold), lowering the effective dose (ED 50/30) to an average of 80 cells. The separative procedure enabled hemopoietic stem cells that repopulate both bone marrow and spleen with secondary RPA cells, CFU-S-12, and CFU-GM to be enriched and separated from part of the RPA cells, CFU-S-12, and cells that reconstitute the cellularity of bone marrow and spleen. These data suggest that cells generating both day-12 CFU-S and RPA cells differ from day-12 CFU-S and RPA cells themselves on the basis of PLS characteristics and affinity for WGA. Such early stem cells have also been detected in sorted fractions meeting the FLS/PLS characteristics of lymphocytes

  16. Cytoplasmic transfer of heritable elements other than mtDNA from SAMP1 mice into mouse tumor cells suppresses their ability to form tumors in C57BL6 mice.

    Science.gov (United States)

    Shimizu, Akinori; Tani, Haruna; Takibuchi, Gaku; Ishikawa, Kaori; Sakurazawa, Ryota; Inoue, Takafumi; Hashimoto, Tetsuo; Nakada, Kazuto; Takenaga, Keizo; Hayashi, Jun-Ichi

    2017-11-04

    In a previous study, we generated transmitochondrial P29mtSAMP1 cybrids, which had nuclear DNA from the C57BL6 (referred to as B6) mouse strain-derived P29 tumor cells and mitochondrial DNA (mtDNA) exogenously-transferred from the allogeneic strain SAMP1. Because P29mtSAMP1 cybrids did not form tumors in syngeneic B6 mice, we proposed that allogeneic SAMP1 mtDNA suppressed tumor formation of P29mtSAMP1 cybrids. To test this hypothesis, current study generated P29mt(sp)B6 cybrids carrying all genomes (nuclear DNA and mtDNA) from syngeneic B6 mice by eliminating SAMP1 mtDNA from P29mtSAMP1 cybrids and reintroducing B6 mtDNA. However, the P29mt(sp)B6 cybrids did not form tumors in B6 mice, even though they had no SAMP1 mtDNA, suggesting that SAMP1 mtDNA is not involved in tumor suppression. Then, we examined another possibility of whether SAMP1 mtDNA fragments potentially integrated into the nuclear DNA of P29mtSAMP1 cybrids are responsible for tumor suppression. We generated P29 H (sp)B6 cybrids by eliminating nuclear DNA from P29mt(sp)B6 cybrids and reintroducing nuclear DNA with no integrated SAMP1 mtDNA fragment from mtDNA-less P29 cells resistant to hygromycin in selection medium containing hygromycin. However, the P29 H (sp)B6 cybrids did not form tumors in B6 mice, even though they carried neither SAMP1 mtDNA nor nuclear DNA with integrated SAMP1 mtDNA fragments. Moreover, overproduction of reactive oxygen species (ROS) and bacterial infection were not involved in tumor suppression. These observations suggest that tumor suppression was caused not by mtDNA with polymorphic mutations or infection of cytozoic bacteria but by hypothetical heritable cytoplasmic elements other than mtDNA from SAMP1 mice. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  17. The importance of confronting a colonial, patriarchal and racist past ...

    African Journals Online (AJOL)

    The importance of confronting a colonial, patriarchal and racist past in addressing post-apartheid sexual violence. ... It also needs to redress problems of social and economic inequality that exist in South Africa as hangovers from this country's colonial and apartheid-era past. Keywords: Zuma, rape, Kipling, colonialism, ...

  18. Military labour mobilisation in colonial Lesotho during World War II ...

    African Journals Online (AJOL)

    In 1940, Great Britain's wartime exploitation of the human and material resources of its colonial empire was extended to colonial Lesotho (then known as Basutoland). The aim of this article, therefore, is to trace the four-year military labour mobilisation process in that colony, with special attention to the timing, number and ...

  19. Deconstructive Pedagogy and Ideological Demystification in Post-Colonial Pakistan

    Science.gov (United States)

    Mansoor, Asma; Malik, Samina

    2016-01-01

    With post-colonial Pakistan inheriting the British colonial ideological and governmental apparatus, the English literature curriculum implemented at the university level in Pakistan carried the interpellatory baggage of its colonial past. Our interdisciplinary exploration focuses on using deconstructive pedagogy to demystify and subvert the…

  20. The Genesis of Public Relations in British Colonial Practice.

    Science.gov (United States)

    Smyth, Rosaleen

    2001-01-01

    Demonstrates how the British Colonial Office employed public relations strategies as they administered the British colony of Northern Rhodesia before, during, and after World War II. Demonstrates how civil servants in London and colonial officials implemented public relations policies, strategies, and tactics on an ad hoc basis, covering political…

  1. African Economic Development and Colonial Legacies

    Directory of Open Access Journals (Sweden)

    Gareth Austin

    2010-03-01

    Full Text Available This article reviews how colonial rule and African actions during the colonial period affected the resources and institutional settings for subsequent economic development south of the Sahara. The issue is seen from the perspective of the dynamics of development in what was in 1900 an overwhelmingly land-abundant region characterised by shortages of labour and capital, by perhaps surprisingly extensive indigenous market activities and by varying but often low levels of political centralisation. The differential impact of French and British rule is explored, but it is argued that a bigger determinant of the differential evolution of poverty, welfare and structural change was the contrast between “settler” and “peasant” economies.

  2. Teaching South Asia beyond Colonial Boundaries

    Directory of Open Access Journals (Sweden)

    Brian Caton

    2014-06-01

    Full Text Available Because of the methodological innovations of Subaltern Studies in the 1980s and 1990s, most historians’ familiarity with South Asian history is limited to the colonial or modern period. While the subalternist view is undoubtedly useful, it does not provide much help in thinking about what came before or after the colonial period. This limited context may prove to be a problem for a non-specialist constructing a full course in South Asian history or adding South Asia content to a course that seeks to break down area studies or nation-state boundaries. This article provides a starting point for such an enterprise. It reviews the South Asian history textbooks available in the market and identifies some of the scholarship that would suit courses or units organized by theme or by a larger Asian geography. It also reviews some of the collections of primary sources that could be used in such coursework.

  3. Observations on the contributions of environmental restraints and innate stem cell ability to hematopoietic regeneration

    International Nuclear Information System (INIS)

    Duke-Cohan, J.S.

    1988-01-01

    A competitive repopulation assay utilizing chromosome markers was used to assay the reconstituting potential of hematopoietic populations. The test populations consisted of tibial murine marrow locally irradiated with doses ranging from 1.5 Gy to 8.5 Gy and of marrow generated from either murine splenic or marrow stem cells. The purpose of this assay was to assess the innate proliferative potential and microenvironmental influences on the ability to repopulate. Regardless of origin, spleen repopulating ability consistently agreed with spleen colony-forming unit (CFU-s) content. Doses of radiation from 5 Gy to 8.5 Gy diminished, by a factor of 2, the ability to repopulate marrow despite maintenance of CFU-s levels. Marrow generated from splenic stem cells had one-fifth the repopulating ability of marrow derived from marrow stem cells, even though CFU-s levels were equivalent. The results imply that the splenic environment can only maintain stem cells at the level of the CFU-s, even if the stem cells were originally of higher quality, and that their original potential cannot be regained in a marrow environment. Nevertheless, the marrow can maintain more primitive stem cells, but this reserve is drained to support CFU-s levels

  4. Glass forming ability and magnetic properties of Co(40.2−x)Fe(20.1+x)Ni6.7B22.7Si5.3Nb5 (x=0–10) bulk metallic glasses produced by suction casting

    International Nuclear Information System (INIS)

    Sarlar, Kagan; Kucuk, Ilker

    2015-01-01

    The effect of Fe concentration on the glass forming ability (GFA) and magnetic properties in Co (40.2−x) Fe (20.1+x) Ni 6.7 B 22.7 Si 5.3 Nb 5 (x=0–10) bulk metallic glasses were investigated. By suction casting method, the bulk metallic glasses with diameters up to 2 mm were produced. We try to find out which Fe concentration makes an influence on Co based system's magnetic properties and glass forming ability. The curves of thermal analysis, obtained using differential scanning calorimetry (DSC), show that the Co (40.2−x) Fe (20.1+x) Ni 6.7 B 22.7 Si 5.3 Nb 5 (x=0–10) have a supercooled liquid region (∆T x ) of about 44 K. The saturation magnetizations (J s ) for as-cast BMG alloys were in the range of 0.62 T−0.81 T. - Highlights: • The effect of Fe concentration on the glass forming ability. • The substitution of an appropriate amount of Fe can enhance the GFA. • The substitution of Fe for Co also improves soft magnetic properties of the BMGs. • The high of J s 0.62−0.81 T with a low H c of 2−289 A/m of the alloys

  5. Ant colony optimization and constraint programming

    CERN Document Server

    Solnon, Christine

    2013-01-01

    Ant colony optimization is a metaheuristic which has been successfully applied to a wide range of combinatorial optimization problems. The author describes this metaheuristic and studies its efficiency for solving some hard combinatorial problems, with a specific focus on constraint programming. The text is organized into three parts. The first part introduces constraint programming, which provides high level features to declaratively model problems by means of constraints. It describes the main existing approaches for solving constraint satisfaction problems, including complete tree search

  6. Results of the radiological survey at 3 Crammond Street, Colonie, New York (AL135)

    International Nuclear Information System (INIS)

    Marley, J.L.

    1987-12-01

    A number of properties in the Albany/Colonie area have been identified as being potentially contaminated with uranium originating from the former National Lead Company's uranium forming plant in Colonie, New York. The property at 3 Crammond Street in Colonie, New York was subject of a radiological investigation initiated November 14, 1985. The property was a vacant, asphalt-paved lot. A diagram of the property showing the approximate boundaries and the 5-m grid network established for measurements is shown. The rectangular lot included in the radiological survey was /approximately/18.5 m wide by 33.7 m deep. A front view of the property is shown. 13 refs., 4 figs., 5 tabs

  7. Results of the radiological survey at 7 Maplewood Avenue, Colonie, New York

    International Nuclear Information System (INIS)

    Marley, J.L.

    1987-12-01

    A number of properties in the Albany/Colonie area have been identified as being potentially contaminated with uranium originating from the former National Lead Company's uranium forming plant in Colonie, New York. The property at 7 Maplewood Avenue in Colonie, New York, was the subject of a radiological investigation initiated May 8, 1986. The residential property consisted of a house and a garage located on a rectangular lot. An asphalt-paved driveway connected the garage with the street. A diagram of the property showing the approximate boundaries and the 4-m grid network established for measurements outside the house is shown. The lot included in the radiological survey was /approximately/12 m wide by 35.5 m deep. Front and rear views of the property are shown. 13 refs., 5 figs., 5 tabs

  8. Representing Distant Victims: The Emergence of an Ethical Movement in Dutch Colonial Politics, 1840-1880

    Directory of Open Access Journals (Sweden)

    Maartje Janse

    2013-03-01

    Full Text Available This article attempts to add to our understanding of the relations between the Netherlands and its colonies in the little researched period of 1840-1880 when this relation became politicised. This was a direct result of a new notion of citizenship that developed after the 1848 constitution was implemented: many believed that citizens had now become accountable for government policies, that is, as far as they were acquainted with the effects these had abroad. Colonial issues were among the first for which citizens developed new protest forms and demanded that public opinion should be taken more seriously by the government. This means that not only what happened in the colonies influenced the shape and structure of Dutch politics in an important formative stage, but also that sentiments usually connected to the introduction of the Ethical Policy can be traced back much earlier than isoften assumed.

  9. Chinua Achebe and the Post-colonial Esthetic: Writing, Identity, and National Formation

    Directory of Open Access Journals (Sweden)

    Simon Gikandi

    1991-01-01

    Full Text Available Chinua Achebe is recognized as one of Africa's most important and influential writers, and his novels have focused on the ways in which the European tradition of the novel and African modes of expression relate to each other in both complementary and contesting ways. Achebe's novels are informed by an important theory of writing which tries to mediate the politics of the novel as a form of commentary on the emergence and transformation of nationalism which constitutes the African writer's epistemological context. Achebe's esthetic has been overdetermined by the changing discourse on representation and national identity in colonial and post-colonial Africa. His anxious quest for a post-colonial esthetic is predicated on the belief that narrative can enable the writer to express an alternative order of things opposed to realities imprisoned by imperialism and Western domination.

  10. Influence of feeding bee colonies on colony strenght and honey authenticity

    Directory of Open Access Journals (Sweden)

    Andreja KANDOLF BOROVŠAK

    2015-12-01

    Full Text Available For the natural development of bee colonies, there is the need for appropriate nutrition. Lack of natural honey flow must be supplemented by feeding bee colonies with sugar syrups or candy paste. This supplementary feeding encourages brood breeding and forage activity, whereby stronger colonies collect more honey. Sugar syrups can cause honey adulteration, which is more frequent with the reversing of the brood combs with the bee food, with the combs moved from the brood chamber to the upper chamber. Authentication of honey from the standpoint of the presence of sugar syrup is very complex, because there is no single method by which honey adulteration can be reliably confirmed. Feeding the colonies in spring should result in stronger colonies and hence the collection of more honey in the brood chambers. The objective of the present study was to determine whether this has effects also on honey authenticity, and to discover a simple method for detection of honey adulteration. The colonies were fed with candy paste that had added yeast and blue dye, to provide markers for detection of honey adulteration. The strength of the colonies and quantity of honey in the brood chambers were monitored. The results of the analysis of stable isotope and activity of foreign enzymes were compared with the results of yeast quantity and colour of the honey (absorbance, L*, a*, b* parameters. Detection of yeast in the honey samples and presence of colour as a consequence of added dye appear to be appropriate methods to follow honey adulteration, and further studies are ongoing.

  11. Review Essay: Governmentality in Late Colonial Korea?

    Directory of Open Access Journals (Sweden)

    Henry Em

    2012-12-01

    Full Text Available Takashi Fujitani, Race for Empire: Koreans as Japanese and Japanese as Americans during World War II. Berkeley: University of California Press, 2011. 520 pp. $65 (cloth.Jun Uchida, Brokers of Empire: Japanese Settler Colonialism in Korea, 1876-1945. Cambridge, MA: Harvard University Press, 2011. 500 pp. $50 (cloth.In South Korea, more so than in most other postcolonial countries, the issue of sovereignty and the colonial past remains a central feature of politics. Most recently, during a televised presidential debate on December 4, 2012, Lee Jung-hee of the Unified Progressive Party said something that likely had never been said on South Korean television: “Takaki Masao signed an oath of loyalty [to the Emperor of Japan], in his own blood, to become an officer in the Japanese [Imperial] Army. You know who he is. His Korean name is Park Chung Hee.” Lee Jung-hee then made the connection between that colonial past and the willingness to sell out the nation’s sovereignty in the present. The conservative candidate Park Geun-hye, the daughter of the late President Park Chung Hee who ruled South Korea from 1961 through 1979, and members of Park’s Saenuri Party, remain true to their “roots”: these “descendants of pro-Japanese collaborators and dictators” (again sold out South Korea’s sovereignty (on November 22, 2011 when they rammed the US-ROK Free Trade Agreement through the National Assembly.

  12. Reproduction and caste ratios under stress in trematode colonies with a division of labour.

    Science.gov (United States)

    Lloyd, Melanie M; Poulin, Robert

    2013-06-01

    Trematodes form clonal colonies in their first intermediate host. Individuals are, depending on species, rediae or sporocysts (which asexually reproduce) and cercariae (which develop within rediae or sporocysts and infect the next host). Some species use a division of labour within colonies, with 2 distinct redial morphs: small rediae (non-reproducing) and large rediae (individuals which produce cercariae). The theory of optimal caste ratio predicts that the ratio of caste members (small to large rediae) responds to environmental variability. This was tested in Philophthalmus sp. colonies exposed to host starvation and competition with the trematode, Maritrema novaezealandensis. Philophthalmus sp. infected snails, with and without M. novaezealandensis, were subjected to food treatments. Reproductive output, number of rediae, and the ratio of small to large rediae were compared among treatments. Philophthalmus sp. colonies responded to host starvation and competition; reproductive output was higher in well-fed snails of both infection types compared with snails in lower food treatments and well-fed, single infected snails compared with well-fed double infected snails. Furthermore, the caste ratio in Philophthalmus sp. colonies was altered in response to competition. This is the first study showing caste ratio responses to environmental pressures in trematodes with a division of labour.

  13. Quantity of Candida Colonies in Saliva: 
A Diagnostic Evaluation for Oral Candidiasis.

    Science.gov (United States)

    Zhou, Pei Ru; Hua, Hong; Liu, Xiao Song

    To investigate the relationship between the quantity of Candida colonies in saliva and oral candidiasis (OC), as well as to identify the threshold for distinguishing oral candidiasis from healthy carriage. A diagnostic test was conducted in 197 patients with different oral problems. The diagnosis of OC was established based on clinical features. Whole saliva samples from the subjects were cultured for Candida species. Receiver operating characteristic (ROC) curve analysis was used in this study. OC patients had significantly more Candida colony-forming units per millilitre saliva (795 cfu/ml) than asymptomatic carriers (40 cfu/ml; P candidiasis, the quantity of Candida colonies differed. The number of Candida colonies in pseudomembranous type was significantly higher than that in the erythematous type (P < 0.05). Candida albicans was the predominant species of Candida. The cut-off point with the best fit for OC diagnosis was calculated to be 266 cfu/ml. The sensitivity and specificity were 0.720 and 0.825, respectively. Analysis of the ROC curve indicated that Candida colonies had a high diagnostic value for OC, as demonstrated by the area under the curve (AUC = 0.873). Based on this study, the value of 270 cfu/ml was considered a threshold for distinguishing OC from carriage.

  14. Assessment of FUN-1 vital dye staining: Yeast with a block in the vacuolar sorting pathway have impaired ability to form CIVS when stained with FUN-1 fluorescent dye.

    Science.gov (United States)

    Essary, Brandin D; Marshall, Pamela A

    2009-08-01

    FUN-1 [2-chloro-4-(2,3-dihydro-3-methyl-(benzo-1,3-thiazol-2-yl)-methylidene)-1-phenylquinolinium iodide] is a fluorescent dye used in studies of yeast and other fungi to monitor cell viability in the research lab and to assay for active fungal infection in the clinical setting. When the plasma membrane is intact, fungal cells internalize FUN-1 and the dye is seen as diffuse green cytosolic fluorescence. FUN-1 is then transported to the vacuole in metabolically active wild type cells and subsequently is compacted into fluorescent red cylindrical intravacuolar structures (CIVS) by an unknown transport pathway. This dye is used to determine yeast viability, as only live cells form CIVS. However, in live Saccharomyces cerevisiae with impaired protein sorting to the yeast vacuole, we report decreased to no CIVS formation, depending on the cellular location of the block in the sorting pathway. Cells with a block in vesicle-mediated transport from the Golgi to prevacuolar compartment (PVC) or with a block in recycling from the PVC to the Golgi demonstrate a substantial impairment in CIVS formation. Instead, the FUN-1 dye is seen either in small punctate structures under fluorescence or as diffuse red cytosol under white light. Thus, researchers using FUN-1 should be cognizant of the limitations of this procedure in determining cell viability as there are viable yeast mutants with impaired CIVS formation.

  15. Physical Forces Modulate Oxidative Status and Stress Defense Meditated Metabolic Adaptation of Yeast Colonies: Spaceflight and Microgravity Simulations

    Science.gov (United States)

    Hammond, Timothy G.; Allen, Patricia L.; Gunter, Margaret A.; Chiang, Jennifer; Giaever, Guri; Nislow, Corey; Birdsall, Holly H.

    2018-05-01

    Baker's yeast ( Saccharomyces cerevisiae) has broad genetic homology to human cells. Although typically grown as 1-2mm diameter colonies under certain conditions yeast can form very large (10 + mm in diameter) or `giant' colonies on agar. Giant yeast colonies have been used to study diverse biomedical processes such as cell survival, aging, and the response to cancer pharmacogenomics. Such colonies evolve dynamically into complex stratified structures that respond differentially to environmental cues. Ammonia production, gravity driven ammonia convection, and shear defense responses are key differentiation signals for cell death and reactive oxygen system pathways in these colonies. The response to these signals can be modulated by experimental interventions such as agar composition, gene deletion and application of pharmaceuticals. In this study we used physical factors including colony rotation and microgravity to modify ammonia convection and shear stress as environmental cues and observed differences in the responses of both ammonia dependent and stress response dependent pathways We found that the effects of random positioning are distinct from rotation. Furthermore, both true and simulated microgravity exacerbated both cellular redox responses and apoptosis. These changes were largely shear-response dependent but each model had a unique response signature as measured by shear stress genes and the promoter set which regulates them These physical techniques permitted a graded manipulation of both convection and ammonia signaling and are primed to substantially contribute to our understanding of the mechanisms of drug action, cell aging, and colony differentiation.

  16. Selective binding and oligomerization of the murine granulocyte colony-stimulating factor receptor by a low molecular weight, nonpeptidyl ligand.

    Science.gov (United States)

    Doyle, Michael L; Tian, Shin-Shay; Miller, Stephen G; Kessler, Linda; Baker, Audrey E; Brigham-Burke, Michael R; Dillon, Susan B; Duffy, Kevin J; Keenan, Richard M; Lehr, Ruth; Rosen, Jon; Schneeweis, Lumelle A; Trill, John; Young, Peter R; Luengo, Juan I; Lamb, Peter

    2003-03-14

    Granulocyte colony-stimulating factor regulates neutrophil production by binding to a specific receptor, the granulocyte colony-stimulating factor receptor, expressed on cells of the granulocytic lineage. Recombinant forms of granulocyte colony-stimulating factor are used clinically to treat neutropenias. As part of an effort to develop granulocyte colony-stimulating factor mimics with the potential for oral bioavailability, we previously identified a nonpeptidyl small molecule (SB-247464) that selectively activates murine granulocyte colony-stimulating factor signal transduction pathways and promotes neutrophil formation in vivo. To elucidate the mechanism of action of SB-247464, a series of cell-based and biochemical assays were performed. The activity of SB-247464 is strictly dependent on the presence of zinc ions. Titration microcalorimetry experiments using a soluble murine granulocyte colony-stimulating factor receptor construct show that SB-247464 binds to the extracellular domain of the receptor in a zinc ion-dependent manner. Analytical ultracentrifugation studies demonstrate that SB-247464 induces self-association of the N-terminal three-domain fragment in a manner that is consistent with dimerization. SB-247464 induces internalization of granulocyte colony-stimulating factor receptor on intact cells, consistent with a mechanism involving receptor oligomerization. These data show that small nonpeptidyl compounds are capable of selectively binding and inducing productive oligomerization of cytokine receptors.

  17. Physical Forces Modulate Oxidative Status and Stress Defense Meditated Metabolic Adaptation of Yeast Colonies: Spaceflight and Microgravity Simulations

    Science.gov (United States)

    Hammond, Timothy G.; Allen, Patricia L.; Gunter, Margaret A.; Chiang, Jennifer; Giaever, Guri; Nislow, Corey; Birdsall, Holly H.

    2017-12-01

    Baker's yeast (Saccharomyces cerevisiae) has broad genetic homology to human cells. Although typically grown as 1-2mm diameter colonies under certain conditions yeast can form very large (10 + mm in diameter) or `giant' colonies on agar. Giant yeast colonies have been used to study diverse biomedical processes such as cell survival, aging, and the response to cancer pharmacogenomics. Such colonies evolve dynamically into complex stratified structures that respond differentially to environmental cues. Ammonia production, gravity driven ammonia convection, and shear defense responses are key differentiation signals for cell death and reactive oxygen system pathways in these colonies. The response to these signals can be modulated by experimental interventions such as agar composition, gene deletion and application of pharmaceuticals. In this study we used physical factors including colony rotation and microgravity to modify ammonia convection and shear stress as environmental cues and observed differences in the responses of both ammonia dependent and stress response dependent pathways We found that the effects of random positioning are distinct from rotation. Furthermore, both true and simulated microgravity exacerbated both cellular redox responses and apoptosis. These changes were largely shear-response dependent but each model had a unique response signature as measured by shear stress genes and the promoter set which regulates them These physical techniques permitted a graded manipulation of both convection and ammonia signaling and are primed to substantially contribute to our understanding of the mechanisms of drug action, cell aging, and colony differentiation.

  18. Combined effects of nitrogen content in media and Ochromonas sp. grazing on colony formation of cultured Microcystis aeruginosa

    Directory of Open Access Journals (Sweden)

    Zhou YANG

    2010-08-01

    Full Text Available To gain insight into the combined effects of nitrogen content in media and flagellate grazing on colony formation of Microcystis aeruginosa, we added Ochromonas sp. to M. aeruginosa cultured in different nitrogen content media for 7 days. Results showed that M. aeruginosa could be efficiently ingested by Ochromonas sp., no matter what nitrogen content media M. aeruginosa was cultured in. Colony formation was observed in M. aeruginosa in all Ochromonas sp. grazing treatments during the experiment. In contrast, M. aeruginosa populations in the controls were strongly dominated by unicellular and paired cell forms, and no colonies were observed. Among all Ochromonas sp. grazing treatments, the mean numbers of cells per particle of M. aeruginosa increased with decreased nitrogen concentration (except 0% N, therefore colony formation of M. aeruginosa can be enhanced under lower nitrogen conditions. This suggests that both nitrogen content and Ochromonas sp. grazing combine to affect M. aeruginosa colony formation. Three-way ANOVA showed a statistically significant interaction between time (day 1, 3, 5, and 7, treatment (with and without Ochromonas sp. grazing and N content (0%, 10%, 25%, and 100% N on the mean numbers of cells per particle, i.e. the extent of colony formation. At the end of the experiment, the influence of nitrogen content (except 0% N on the numbers of cells per particle followed a rectangular hyperbolic response. The experiments demonstrated that there exists a combined effect of nitrogen concentration and flagellate grazing on colony formation of M. aeruginosa under laboratory conditions.

  19. Morphological Diversity of the Colony Produced by Bacteria Proteus mirabilis

    Science.gov (United States)

    Nakahara, Akio; Shimada, Yuji; Wakita, Jun-ichi; Matsushita, Mitsugu; Matsuyama, Tohey

    1996-08-01

    Morphological changes of colonies have been investigatedfor a bacterial strain of Proteus mirabilis, which is a famous speciesfor producing concentric-ring-like colonies. It was found that colony patterns can be classified into three types,i.e., cyclic spreading, diffusion-limited growth (DLA-like)and three-dimensional growth (inside the agar medium) patterns. Cyclic spreading patterns can further be classifiedinto three subgroups, i.e., concentric-ring, homogeneous and spatiotemporal patterns. These subgroups were classified by examining the development of colony structure after colonies spread all over petri-dishes. Comparison of the results with thoseof another bacterial species Bacillus subtilis is also discussed.

  20. Life in the colonies: learning the alien ways of colonial organisms.

    Science.gov (United States)

    Winston, Judith E

    2010-12-01

    Who needs to go to outer space to study alien beings when the oceans of our own planet abound with bizarre and unknown creatures? Many of them belong to sessile clonal and colonial groups, including sponges, hydroids, corals, octocorals, ascidians, bryozoans, and some polychaetes. Their life histories, in many ways unlike our own, are a challenge for biologists. Studying their ecology, behavior, and taxonomy means trying to “think like a colony” to understand the factors important in their lives. Until the 1980s, most marine ecologists ignored these difficult modular organisms. Plant ecologists showed them ways to deal with the two levels of asexually produced modules and genetic individuals, leading to a surge in research on the ecology of clonal and colonial marine invertebrates. Bryozoans make excellent model colonial animals. Their life histories range from ephemeral to perennial. Aspects of their lives such as growth, reproduction, partial mortality due to predation or fouling, and the behavior of both autozooids and polymorphs can be studied at the level of the colony, as well as that of the individual module, in living colonies and over time.

  1. Engaging With Colonial Archives: Reflections Of An End-User

    Directory of Open Access Journals (Sweden)

    Ayodeji Olukoju

    2016-06-01

    Full Text Available Official and/or public archives were a byproduct of colonial rule in Africa. (Archives are a byproduct of administrative governance everywhere. Given the density and diversity of colonial archival records, historians have tended to rely on them for the study of the colonial period. Publications on the use of archives have not captured the perspective of end-users, who often face peculiar challenges in the use of colonial and metropolitan archives. This paper provides an end-user perspective on colonial archives in Nigeria and the United Kingdom. It highlights the challenges of data collection and prospects of optimal use of archival source material. The discussion is of general application to users of colonial archives especially in the former British colonies in Africa.

  2. Experimental Study for Automatic Colony Counting System Based Onimage Processing

    Science.gov (United States)

    Fang, Junlong; Li, Wenzhe; Wang, Guoxin

    Colony counting in many colony experiments is detected by manual method at present, therefore it is difficult for man to execute the method quickly and accurately .A new automatic colony counting system was developed. Making use of image-processing technology, a study was made on the feasibility of distinguishing objectively white bacterial colonies from clear plates according to the RGB color theory. An optimal chromatic value was obtained based upon a lot of experiments on the distribution of the chromatic value. It has been proved that the method greatly improves the accuracy and efficiency of the colony counting and the counting result is not affected by using inoculation, shape or size of the colony. It is revealed that automatic detection of colony quantity using image-processing technology could be an effective way.

  3. Varroa-Virus Interaction in Collapsing Honey Bee Colonies

    DEFF Research Database (Denmark)

    Francis, Roy Mathew; Nielsen, Steen L.; Kryger, Per

    2013-01-01

    Varroa mites and viruses are the currently the high-profile suspects in collapsing bee colonies. Therefore, seasonal variation in varroa load and viruses (Acute-Kashmir-Israeli complex (AKI) and Deformed Wing Virus (DWV)) were monitored in a year-long study. We investigated the viral titres...... in honey bees and varroa mites from 23 colonies (15 apiaries) under three treatment conditions: Organic acids (11 colonies), pyrethroid (9 colonies) and untreated (3 colonies). Approximately 200 bees were sampled every month from April 2011 to October 2011, and April 2012. The 200 bees were split to 10...... subsamples of 20 bees and analysed separately, which allows us to determine the prevalence of virus-infected bees. The treatment efficacy was often low for both treatments. In colonies where varroa treatment reduced the mite load, colonies overwintered successfully, allowing the mites and viruses...

  4. Viability of honeybee colonies exposed to sunflowers grown from seeds treated with the neonicotinoids thiamethoxam and clothianidin.

    Science.gov (United States)

    Hernando, M Dolores; Gámiz, Victoria; Gil-Lebrero, Sergio; Rodríguez, Inmaculada; García-Valcárcel, Ana I; Cutillas, V; Fernández-Alba, Amadeo R; Flores, José M

    2018-07-01

    In this study, honeybee colonies were monitored in a field study conducted on sunflowers grown from seeds treated with the systemic neonicotinoids thiamethoxam or clothianidin. This field trial was carried out in different representative growing areas in Spain over a beekeeping season. The health and development of the colonies was assessed by measuring factors that have a significant influence on their strength and overwintering ability. The parameters assessed were: colony strength (adult bees), brood development, amount of pollen and honey stores and presence and status of the queen. The concentration of residues (clothianidin and thiamethoxam) in samples of beebread and in adult bees was at the level of ng.g -1 ; in the ranges of 0.10-2.89 ng g -1 and 0.05-0.12 ng g -1 ; 0.10-0.37 ng g -1 and 0.01-0.05 ng g -1 , respectively. Multivariate models were applied to evaluate the interaction among factors. No significant differences were found between the honeybee colonies of the different treatment groups, either exposed or not to the neonicotinoids. The seasonal development of the colonies was affected by the environmental conditions which, together with the initial strength of the bee colonies and the characteristics of the plots, had a significant effect on the different variables studied. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Pollen foraging in colonies of Melipona bicolor (Apidae, Meliponini): effects of season, colony size and queen number.

    Science.gov (United States)

    Hilário, S D; Imperatriz-Fonseca, V L

    2009-01-01

    We evaluated the ratio between the number of pollen foragers and the total number of bees entering colonies of Melipona bicolor, a facultative polygynous species of stingless bees. The variables considered in our analysis were: seasonality, colony size and the number of physogastric queens in each colony. The pollen forager ratios varied significantly between seasons; the ratio was higher in winter than in summer. However, colony size and number of queens per colony had no significant effect. We conclude that seasonal differences in pollen harvest are related to the production of sexuals and to the number of individuals and their body size.

  6. Metabolism and resources of spherical colonies of Nostoc zetterstedtii

    DEFF Research Database (Denmark)

    Jensen, Kaj Sand; Raun, Ane-Marie Løvendahl; Borum, Jens

    2009-01-01

    Constraints imposed by the spherical form and gelatinous matrix of centimeter-thick colonies of the cyanobacterium Nostoc zetterstedtii on its functional properties were tested by examining the scaling of its composition, light absorption, photosynthesis, and respiration to individual size....... Nostoc absorbed 96% of incident light from the surface to the center because of high areal pigment density, but absorbed photons were used with low quantum efficiency (11- 38 mmol O2 mol21 photon) and photosynthesis was low relative to dark respiration (2.0-5.4). Therefore, N. zetterstedtii is threatened...... by reduced light availability and only extended to lake depths receiving about 12% of surface irradiance, whereas mosses, characeans, and angiosperms with thin photosynthetic tissues grew deeper (3.1-7.5% of surface irradiance). Nostoc ameliorated the restrictions of low lake DIC and long diffusion paths...

  7. Compulsory Land Acquisitions In Tanganyika Revisiting The British Colonial Expropriation Principles And Practices

    Directory of Open Access Journals (Sweden)

    Cletus Eligius Ndjovu

    2015-08-01

    Full Text Available Abstract The British took over Tanganyika from the Germans in 1919 after the First World War. In facilitating colonial economic policies the British Colonial Government enacted Land Ordinance Cap 113 of 1923 and Land Acquisition Ordinance Cap 118 of 1926. These laws facilitated the acquisition of native lands and considerably changed the way expropriation was handled leaving behind permanent marks on the later practice. The colonial practice exposed the inner most economic intents of the British government. Use of legal phrases like for public purpose embedded in the ordinance had multiple legal interpretations and loose definition befitting the colonial economic cravings of the time. Although major provisions of the colonial acquisition laws are reflected in the later laws evidence suggests that a few elements of colonial expropriation practices have also sneaked in as silent laws of expropriation but others have not. Quite a few practices had been deliberately discarded or inadvertently forgotten for lack of a political will to purify and emulate them or due to lack of good record keeping. Using historical data and archival records from the Tanzania National Archives this study explored colonial expropriations mainly by focusing on the principles laws practices and procedures used. The main objective of the study was to identify good practices used during the said era the intended and unintended consequences of these unreported practices especially those which need to be emulated by the current laws and practices. The study concluded by shedding light on bad practices which are being exercised to date uncritically but also acknowledging good colonial expropriation practices which existed then but could be emulated. First the study insists that public purpose clause in expropriation must be affected with good and fair intentions and a mechanism to check this be set. Secondly PAPs involvement in land acquisition and compensation negotiations

  8. Metal contaminant accumulation in the hive: Consequences for whole-colony health and brood production in the honey bee (Apis mellifera L.).

    Science.gov (United States)

    Hladun, Kristen R; Di, Ning; Liu, Tong-Xian; Trumble, John T

    2016-02-01

    Metal pollution has been increasing rapidly over the past century, and at the same time, the human population has continued to rise and produce contaminants that may negatively impact pollinators. Honey bees (Apis mellifera L.) forage over large areas and can collect contaminants from the environment. The primary objective of the present study was to determine whether the metal contaminants cadmium (Cd), copper (Cu), lead (Pb), and selenium (Se) can have a detrimental effect on whole-colony health in the managed pollinator A. mellifera. The authors isolated small nucleus colonies under large cages and fed them an exclusive diet of sugar syrup and pollen patty spiked with Cd, Cu, Pb, and Se or a control (no additional metal). Treatment levels were based on concentrations in honey and pollen from contaminated hives around the world. They measured whole-colony health including wax, honey, and brood production; colony weight; brood survival; and metal accumulation in various life stages. Colonies treated with Cd or Cu contained more dead pupae within capped cells compared with control, and Se-treated colonies had lower total worker weights compared to control. Lead had a minimal effect on colony performance, although many members of the hive accumulated significant quantities of the metal. By examining the honey bee as a social organism through whole-colony assessments of toxicity, the authors found that the distribution of toxicants throughout the colony varied from metal to metal, some caste members were more susceptible to certain metals, and the colony's ability to grow over time may have been reduced in the presence of Se. Apiaries residing near metal-contaminated areas may be at risk and can suffer changes in colony dynamics and survival. © 2015 SETAC.

  9. An Improved Ant Colony Algorithm for Solving the Path Planning Problem of the Omnidirectional Mobile Vehicle

    Directory of Open Access Journals (Sweden)

    Jiang Zhao

    2016-01-01

    Full Text Available This paper presents an improved ant colony algorithm for the path planning of the omnidirectional mobile vehicle. The purpose of the improved ant colony algorithm is to design an appropriate route to connect the starting point and ending point of the environment with obstacles. Ant colony algorithm, which is used to solve the path planning problem, is improved according to the characteristics of the omnidirectional mobile vehicle. And in the improved algorithm, the nonuniform distribution of the initial pheromone and the selection strategy with direction play a very positive role in the path search. The coverage and updating strategy of pheromone is introduced to avoid repeated search reducing the effect of the number of ants on the performance of the algorithm. In addition, the pheromone evaporation coefficient is segmented and adjusted, which can effectively balance the convergence speed and search ability. Finally, this paper provides a theoretical basis for the improved ant colony algorithm by strict mathematical derivation, and some numerical simulations are also given to illustrate the effectiveness of the theoretical results.

  10. Intraspecific Variation among Social Insect Colonies: Persistent Regional and Colony-Level Differences in Fire Ant Foraging Behavior.

    Directory of Open Access Journals (Sweden)

    Alison A Bockoven

    Full Text Available Individuals vary within a species in many ecologically important ways, but the causes and consequences of such variation are often poorly understood. Foraging behavior is among the most profitable and risky activities in which organisms engage and is expected to be under strong selection. Among social insects there is evidence that within-colony variation in traits such as foraging behavior can increase colony fitness, but variation between colonies and the potential consequences of such variation are poorly documented. In this study, we tested natural populations of the red imported fire ant, Solenopsis invicta, for the existence of colony and regional variation in foraging behavior and tested the persistence of this variation over time and across foraging habitats. We also reared single-lineage colonies in standardized environments to explore the contribution of colony lineage. Fire ants from natural populations exhibited significant and persistent colony and regional-level variation in foraging behaviors such as extra-nest activity, exploration, and discovery of and recruitment to resources. Moreover, colony-level variation in extra-nest activity was significantly correlated with colony growth, suggesting that this variation has fitness consequences. Lineage of the colony had a significant effect on extra-nest activity and exploratory activity and explained approximately half of the variation observed in foraging behaviors, suggesting a heritable component to colony-level variation in behavior.

  11. Discourse abilities in the structure of intelligence

    Directory of Open Access Journals (Sweden)

    Voronin A. N.

    2017-09-01

    Full Text Available Background. This article is devoted to empirical research on discourse abilities within the structure of cognitive abilities. Discourse abilities, as well as linguistic abilities, are part of language abilities, but they are directly linked with discourse practices and a certain communicative situation. Discourse abilities allow a person to effectively initiate, keep, expand, and complete the process of communication, using language appropriate to any given situation. These abilities contribute to making communication more effective and achieving mutual understanding between partners, while at the same time they speed up the process of forming an interaction strategy. the empirical verification of the construct “discourse abilities,” and the design of original diagnostic tests on them, led us to differentiate linguistic and discourse abilities. Objective. However, it is not yet clear what place discourse abilities occupy in the structure of cognitive abilities. This is the primary goal of our research. Method. The design of the study involved group testing (in groups of 15-35 people using the following methods: a discourse abilities test; a short selection test; a social intelligence test, and short variations of Torrance’s and Mednick’s tests. In total, 208 people (133 women and 75 men, ages 17 to 21 years participated in the study, all of them either first year humanities students or high school students from Moscow. Results and Discussion. The research results revealed that discourse abilities relevantly correlate with the majority of indicators of general and social intelligence and creativity (except non-verbal intelligence. Discourse abilities as part of the structure of cognitive capabilities form a discrete factor, and include relevant components such as verbal and general intelligence and indicators of social intelligence, such as the ability to group expressions. Structures indicative of cognitive abilities varied within the

  12. Grazing on colonial and filamentous, toxic and non-toxic cyanobacteria by the zebra mussel Dreissena polymorpha

    NARCIS (Netherlands)

    Pires, L.M.D.; Bontes, B.M.; Van Donk, E.; Ibelings, B.W.

    2005-01-01

    Colony forming and toxic cyanobacteria form a problem in surface waters of shallow lakes, both for recreation and wildlife. Zebra mussels, Dreissena polymorpha, have been employed to help to restore shallow lakes in the Netherlands, dominated by cyanobacteria, to their former clear state. Zebra

  13. Developmental plasticity of bacterial colonies and consortia in germ-free and gnotobiotic settings

    Directory of Open Access Journals (Sweden)

    Pátková Irena

    2012-08-01

    Full Text Available Abstract Background Bacteria grown on semi-solid media can build two types of multicellular structures, depending on the circumstances. Bodies (colonies arise when a single clone is grown axenically (germ-free, whereas multispecies chimeric consortia contain monoclonal microcolonies of participants. Growth of an axenic colony, mutual interactions of colonies, and negotiation of the morphospace in consortial ecosystems are results of intricate regulatory and metabolic networks. Multicellular structures developed by Serratia sp. are characteristically shaped and colored, forming patterns that reflect their growth conditions (in particular medium composition and the presence of other bacteria. Results Building on our previous work, we developed a model system for studying ontogeny of multicellular bacterial structures formed by five Serratia sp. morphotypes of two species grown in either "germ-free" or "gnotobiotic" settings (i.e. in the presence of bacteria of other conspecific morphotype, other Serratia species, or E. coli. Monoclonal bodies show regular and reproducible macroscopic appearance of the colony, as well as microscopic pattern of its growing margin. Standard development can be modified in a characteristic and reproducible manner in close vicinity of other bacterial structures (or in the presence of their products. Encounters of colonies with neighbors of a different morphotype or species reveal relationships of dominance, cooperation, or submission; multiple interactions can be summarized in "rock – paper – scissors" network of interrelationships. Chimerical (mixed plantings consisting of two morphotypes usually produced a “consortium” whose structure is consistent with the model derived from interaction patterns observed in colonies. Conclusions Our results suggest that development of a bacterial colony can be considered analogous to embryogenesis in animals, plants, or fungi: to proceed, early stages require thorough

  14. Combined Final Report for Colony II Project

    Energy Technology Data Exchange (ETDEWEB)

    Kale, Laxmikant [University of Illinois; Jones, Terry [Oak Ridge National Laboratory; Moreira, Jose [IBM Corp.

    2013-10-23

    (This report was originally submmited by the lead PI (Terry Jones, ORNL) on October 22, 2013 to the program manager, Lucy Nowell. It is being submitted from University of Illinois in accordance with instructions). HPC Colony II seeks to provide portable performance for leadership class machines. Our strategy is based on adaptive system software that aims to make the intelligent decisions necessary to allow domain scientists to safely focus on their task at hand and allow the system software stack to adapt their application to the underlying architecture. This report describes the research undertaken towards these objectives and the results obtained over the performance period of the project.

  15. Colonial Subjectification: Foucault, Christianity and Governmentality

    Directory of Open Access Journals (Sweden)

    Christina Petterson

    2012-09-01

    Full Text Available Foucault’s concept of pastoral power is envisioned as a technique of power developed from the medieval period and carried through into modern political rationalities. As such, it is an old power technique – which originated in Christian institutions – in a new political shape, which he coined governmentality. This article uses Foucault’s genealogy of pastoral power and governmentality to discuss the intersection of domination and technology of self in the Greenlandic colonial context and to bring out the central role of religion in Foucault’s conceptualisation of governmentality.

  16. Image Edge Tracking via Ant Colony Optimization

    Science.gov (United States)

    Li, Ruowei; Wu, Hongkun; Liu, Shilong; Rahman, M. A.; Liu, Sanchi; Kwok, Ngai Ming

    2018-04-01

    A good edge plot should use continuous thin lines to describe the complete contour of the captured object. However, the detection of weak edges is a challenging task because of the associated low pixel intensities. Ant Colony Optimization (ACO) has been employed by many researchers to address this problem. The algorithm is a meta-heuristic method developed by mimicking the natural behaviour of ants. It uses iterative searches to find the optimal solution that cannot be found via traditional optimization approaches. In this work, ACO is employed to track and repair broken edges obtained via conventional Sobel edge detector to produced a result with more connected edges.

  17. In the Post-Colonial Waiting Room

    DEFF Research Database (Denmark)

    Adler-Nissen, Rebecca; Gad, Ulrik Pram

    2017-01-01

    ready for sovereignty. It explores a number of European overseas countries and territories. More specifically, it focuses on French dependencies in the Pacific and Indian Oceans, and North Atlantic Greenland constitutionally connected to Denmark. The immediate aim of anti-colonial struggles was to make...... acknowledge. A number of overseas territories take alternative routes to agency; not by resisting the norm of sovereignty - but by creatively articulating it beyond its claim to represent an 'either/or' distinction. The chapter demonstrates that territories not formally decolonized may very well perform...

  18. CHRISTIANITY AND COLONIALISM IN SOME ENGLISH SHORT STORIES

    Directory of Open Access Journals (Sweden)

    Tatang Iskarna

    2017-04-01

    Full Text Available Colonial and postcolonial studies are often linked to the power domination of the West upon the East in the way that the East economically, politically, and socially oppressed. Colonialism is often associated with three elements, the explorers dealing with geographical information, missionaries approaching the local people culturally, and the colonial administrators ruling the colony. Gold, glory, and gospel are the European’s concern. However, in representing the relation between Christianity and colonialism there is critical dialectic amongst historians, anthropologists, Christian missions, or cultural critics. Some propose that Christianity is considered to be the religious arm of colonialism. Others state that Christianity is spread without any secular interest as it is a great commandment of Jesus Christ. A few believe that Christianity give critical resistance against colonialism. The relation between Christianity and colonialism cannot be simplified as being neutral, in complicity, or in opposition. So, it is worth-discussing to understand how European writers construct the relation between Christianity and colonialism in their literary work. How Christianity is constructed and how Christianity is related to colonialism will be discussed in this paper. Using postcolonial paradigm, two English short stories will be analyzed in that way. They are Rudyard Kipling’s “Lispeth” and Doris Lessing’s “No Witchcraft for Sale”.

  19. Inbred or Outbred? Genetic Diversity in Laboratory Rodent Colonies

    Science.gov (United States)

    Brekke, Thomas D.; Steele, Katherine A.; Mulley, John F.

    2017-01-01

    Nonmodel rodents are widely used as subjects for both basic and applied biological research, but the genetic diversity of the study individuals is rarely quantified. University-housed colonies tend to be small and subject to founder effects and genetic drift; so they may be highly inbred or show substantial genetic divergence from other colonies, even those derived from the same source. Disregard for the levels of genetic diversity in an animal colony may result in a failure to replicate results if a different colony is used to repeat an experiment, as different colonies may have fixed alternative variants. Here we use high throughput sequencing to demonstrate genetic divergence in three isolated colonies of Mongolian gerbil (Meriones unguiculatus) even though they were all established recently from the same source. We also show that genetic diversity in allegedly “outbred” colonies of nonmodel rodents (gerbils, hamsters, house mice, deer mice, and rats) varies considerably from nearly no segregating diversity to very high levels of polymorphism. We conclude that genetic divergence in isolated colonies may play an important role in the “replication crisis.” In a more positive light, divergent rodent colonies represent an opportunity to leverage genetically distinct individuals in genetic crossing experiments. In sum, awareness of the genetic diversity of an animal colony is paramount as it allows researchers to properly replicate experiments and also to capitalize on other genetically distinct individuals to explore the genetic basis of a trait. PMID:29242387

  20. Political instability and discontinuity in Nigeria: The pre-colonial past and public goods provision under colonial and post-colonial political orders

    NARCIS (Netherlands)

    Papaioannou, K.I.; Dalrymple-Smith, A.E.

    2015-01-01

    This article explores the relative importance of pre-colonial institutional capacity and the effects of periods of peace and stability on long-term development outcomes in Nigeria. We use data on education, health, and public works at a provincial level from a variety of colonial and Nigerian state

  1. Measuring Creative Imagery Abilities

    Directory of Open Access Journals (Sweden)

    Dorota M. Jankowska

    2015-10-01

    Full Text Available Over the decades, creativity and imagination research developed in parallel, but they surprisingly rarely intersected. This paper introduces a new theoretical model of creative imagination, which bridges creativity and imagination research, as well as presents a new psychometric instrument, called the Test of Creative Imagery Abilities (TCIA, developed to measure creative imagery abilities understood in accordance with this model. Creative imagination is understood as constituted by three interrelated components: vividness (the ability to create images characterized by a high level of complexity and detail, originality (the ability to produce unique imagery, and transformativeness (the ability to control imagery. TCIA enables valid and reliable measurement of these three groups of abilities, yielding the general score of imagery abilities and at the same time making profile analysis possible. We present the results of eight studies on a total sample of more than 1,700 participants, showing the factor structure of TCIA using confirmatory factor analysis, as well as provide data confirming this instrument’s validity and reliability. The availability of TCIA for interested researchers may result in new insights and possibilities of integrating the fields of creativity and imagination science.

  2. Glass forming ability and magnetic properties of Co{sub (40.2−x)}Fe{sub (20.1+x)}Ni{sub 6.7}B{sub 22.7}Si{sub 5.3}Nb{sub 5} (x=0–10) bulk metallic glasses produced by suction casting

    Energy Technology Data Exchange (ETDEWEB)

    Sarlar, Kagan [Physics Department, Faculty of Arts and Sciences, Uludag University, Gorukle Campus, 16059 Bursa (Turkey); Physics Department, Kamil Ozdag Faculty of Sciences, Karamanoglu Mehmetbey University, YunusEmre Campus, 70100 Karaman (Turkey); Kucuk, Ilker, E-mail: ikucuk@uludag.edu.tr [Physics Department, Faculty of Arts and Sciences, Uludag University, Gorukle Campus, 16059 Bursa (Turkey)

    2015-01-15

    The effect of Fe concentration on the glass forming ability (GFA) and magnetic properties in Co{sub (40.2−x)}Fe{sub (20.1+x)}Ni{sub 6.7}B{sub 22.7}Si{sub 5.3}Nb{sub 5} (x=0–10) bulk metallic glasses were investigated. By suction casting method, the bulk metallic glasses with diameters up to 2 mm were produced. We try to find out which Fe concentration makes an influence on Co based system's magnetic properties and glass forming ability. The curves of thermal analysis, obtained using differential scanning calorimetry (DSC), show that the Co{sub (40.2−x)}Fe{sub (20.1+x)}Ni{sub 6.7}B{sub 22.7}Si{sub 5.3}Nb{sub 5} (x=0–10) have a supercooled liquid region (∆T{sub x}) of about 44 K. The saturation magnetizations (J{sub s}) for as-cast BMG alloys were in the range of 0.62 T−0.81 T. - Highlights: • The effect of Fe concentration on the glass forming ability. • The substitution of an appropriate amount of Fe can enhance the GFA. • The substitution of Fe for Co also improves soft magnetic properties of the BMGs. • The high of J{sub s} 0.62−0.81 T with a low H{sub c} of 2−289 A/m of the alloys.

  3. Disrupting the Coloniality of Being: Toward De-Colonial Ontologies in Philosophy of Education

    Science.gov (United States)

    Richardson, Troy A.

    2012-01-01

    This essay works to bridge conversations in philosophy of education with decolonial theory. The author considers Margonis' (1999, 2011a, b) use of Rousseau (1979) and Heidegger (1962) in developing an ontological attitude that counters social hierarchies and promotes anti-colonial relations. While affirming this effort, the essay outlines a…

  4. The regulation of British colonial lunatic asylums and the origins of colonial psychiatry, 1860-1864.

    Science.gov (United States)

    Swartz, Sally

    2010-05-01

    In this paper I outline a brief period in the history of the British Empire, during which colonial lunatic asylum policy began to be formulated. I begin with a scandal that erupted in Jamaica and suggest that this set in motion processes that led to critical changes in asylum administration. The first of these processes was an audit of hospitals and asylums in the colonies. The results of the audit and the policy that emerged from it marked the beginning of systematic regulation of lunatic asylum practice across the British Empire. It revealed a formulation of policy that was intended to cut across the self-governing regimes that had up to this point been allowed to evolve. Drawing on the work of Michel Foucault and Nikolas Rose, I argue that the policy and the practices associated with it contribute to an understanding of the emergence of the psy-sciences in colonial settings. They illustrate the establishment of a panoptic gaze on previously neglected insane spaces. Systematic surveillance constituted government at a distance and made colonial lunacy administration a governable discursive space. The regulation of the medical officers, lunatic attendants, and hospital boards began the process of creating a professional psychiatric workforce. I conclude with a discussion of the implications and the mixed impact of this policy change for the mentally ill across the empire, over the ensuing decades.

  5. Economic mobility in a colonial and post-colonial economy: the case of Indonesia.

    NARCIS (Netherlands)

    van Leeuwen, Bas; Földvári, Peter

    2016-01-01

    Despite a consensus about the main factors influencing economic mobility in Indonesia, such as labor-market opportunities and childhood circumstances, virtually nothing is known about how these factors increased economic standing in the colonial and postcolonial periods. The use of height data as a

  6. Stable isotope enrichment in laboratory ant colonies: effects of colony age, metamorphosis, diet, and fat storage

    Science.gov (United States)

    Ecologists use stable isotopes to infer diets and trophic levels of animals in food webs, yet some assumptions underlying these inferences have not been thoroughly tested. We used laboratory-reared colonies of Solenopsis invicta Buren (Formicidae: Solenopsidini) to test the effects of metamorphosis,...

  7. Fish skin bacteria: Colonial and cellular hydrophobicity.

    Science.gov (United States)

    Sar, N; Rosenberg, E

    1987-05-01

    Bacteria were desorbed from the skin of healthy, fast-swimming fish by several procedures, including brief exposure to sonic oscillation and treatment with nontoxic surface active agents. The surface properties of these bacteria were studied by measuring their adhesion to hexadecane, as well as by a newly developed, simple method for studying the hydrophobicity of bacterial lawns. This method, referred to as the "Direction of Spreading" (DOS) method, consists of recording the direction to which a water drop spreads when introduced at the border between bacterial lawns and other surfaces. Of the 13 fish skin isolates examined, two strains were as hydrophobic as polystyrene by the DOS method. Suspended cells of one of these strains adhered strongly to hexadecane (84%), whereas cells of the other strain adhered poorly (13%). Another strain which was almost as hydrophobic as polystyrene by the DOS method did not adhere to hexadecane at all. Similarly, lawns of three other strains were more hydrophobic than glass by the DOS method, but cell suspensions prepared from these colonies showed little or no adhesion to hexadecane. The high colonial but relatively low cellular hydrophobicity could be due to a hydrophobic slime that is removed during the suspension and washing procedures. The possibility that specific bacteria assist in fish locomotion by changing the surface properties of the fish skin and by producing drag-reducing polymers is discussed.

  8. A thermodynamic approach towards glass-forming ability of ...

    Indian Academy of Sciences (India)

    A quantitative measure of the stability of a glass as compared to its corresponding crystalline state can be obtained by calculating ... The thermal stability of various alloy compositions is studied by ... corrosion resistance and attractive soft magnetic behaviour.1,2 .... The value of R2 determines the relationship between GFA.

  9. Poor glass-forming ability of Fe-based alloys

    DEFF Research Database (Denmark)

    Zheng, H.J.; Hu, L.N.; Zhao, X.

    2017-01-01

    processes. By using the concept of fluid cluster and supercooled liquid fragility in metallic liquids, it has been found that this dynamic transition makes the Fe-based supercooled liquids become more unstable, which leads to the poor GFA of Fe-based alloys. Further, it has been found that the degree...

  10. Girls underestimate maths ability

    Science.gov (United States)

    2017-05-01

    A study by psychologists in the US has found that high-school girls rate their competence in mathematics lower than boys, even for those with similar abilities (Front. Psychol. 10.3389/fpsyg.2017.00386).

  11. First recorded loss of an emperor penguin colony in the recent period of Antarctic regional warming: implications for other colonies.

    Directory of Open Access Journals (Sweden)

    Philip N Trathan

    Full Text Available In 1948, a small colony of emperor penguins Aptenodytes forsteri was discovered breeding on Emperor Island (67° 51' 52″ S, 68° 42' 20″ W, in the Dion Islands, close to the West Antarctic Peninsula (Stonehouse 1952. When discovered, the colony comprised approximately 150 breeding pairs; these numbers were maintained until 1970, after which time the colony showed a continuous decline. By 1999 there were fewer than 20 pairs, and in 2009 high-resolution aerial photography revealed no remaining trace of the colony. Here we relate the decline and loss of the Emperor Island colony to a well-documented rise in local mean annual air temperature and coincident decline in seasonal sea ice duration. The loss of this colony provides empirical support for recent studies (Barbraud & Weimerskirch 2001; Jenouvrier et al 2005, 2009; Ainley et al 2010; Barber-Meyer et al 2005 that have highlighted the vulnerability of emperor penguins to changes in sea ice duration and distribution. These studies suggest that continued climate change is likely to impact upon future breeding success and colony viability for this species. Furthermore, a recent circumpolar study by Fretwell & Trathan (2009 highlighted those Antarctic coastal regions where colonies appear most vulnerable to such changes. Here we examine which other colonies might be at risk, discussing various ecological factors, some previously unexplored, that may also contribute to future declines. The implications of this are important for future modelling work and for understanding which colonies actually are most vulnerable.

  12. Coalescing colony model: Mean-field, scaling, and geometry

    Science.gov (United States)

    Carra, Giulia; Mallick, Kirone; Barthelemy, Marc

    2017-12-01

    We analyze the coalescing model where a `primary' colony grows and randomly emits secondary colonies that spread and eventually coalesce with it. This model describes population proliferation in theoretical ecology, tumor growth, and is also of great interest for modeling urban sprawl. Assuming the primary colony to be always circular of radius r (t ) and the emission rate proportional to r (t) θ , where θ >0 , we derive the mean-field equations governing the dynamics of the primary colony, calculate the scaling exponents versus θ , and compare our results with numerical simulations. We then critically test the validity of the circular approximation for the colony shape and show that it is sound for a constant emission rate (θ =0 ). However, when the emission rate is proportional to the perimeter, the circular approximation breaks down and the roughness of the primary colony cannot be discarded, thus modifying the scaling exponents.

  13. Beyond denial and exclusion: The history of relations between Christians and Muslims in the Cape Colony during the 17th–18th centuries with lessons for a post-colonial theology of religions

    Directory of Open Access Journals (Sweden)

    Jaco Beyers

    2016-04-01

    Full Text Available Learning from the past prepares one for being able to cope with the future. History is made up of strings of relationships. This article follows a historical line from colonialism, through apartheid to post-colonialism in order to illustrate inter-religious relations in South-Africa and how each context determines these relations. Social cohesion is enhanced by a post-colonial theology of religions based on the current context. By describing the relationship between Christians and Muslims during the 17th–18th centuries in the Cape Colony, lessons can be deduced to guide inter-religious relations in a post-colonial era in South Africa. One of the most prominent Muslim leaders during the 17th century in the Cape Colony was Sheik Yusuf al-Makassari. His influence determined the future face of Islam in the Cape Colony and here, during the 18th century, ethics started playing a crucial role in determining the relationship between Christians and Muslims. The ethical guidance of the Imams formed the Muslim communities whilst ethical decline was apparent amongst the Christian colonists during the same period. The place of ethics as determinative of future inter-religious dialogue is emphasised. Denial and exclusion characterised relationships between Christians and Muslims. According to a post-colonial understanding of inter-religious contact the equality and dignity of non-Christian religions are to be acknowledged. In the postcolonial and postapartheid struggle for equality, also of religions, prof Graham Duncan, to whom this article is dedicated, contributed to the process of acknowledging the plurality of the religious reality in South Africa.

  14. Influence of Y, Gd and Sm on the glass forming ability and thermal crystallization of aluminum based alloy; Efeito das terras raras Y, Gd e Sm na tendencia a formacao de amorfo e na cristalizacao termica em ligas a base de aluminio

    Energy Technology Data Exchange (ETDEWEB)

    Aliaga, L.C.R.; Bolfarini, C.; Kiminami, C.S.; Botta Filho, W.J., E-mail: aliaga@ufscar.b [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais; Danez, G.P. [Universidade Federal de Sao Carlos (PPG-CEMUFSCar), SP (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais

    2010-07-01

    Al-based amorphous alloys represent an important family of metals and a great scientific activity has been devoted to determine the main features of both glass forming ability (GFA) and crystallization behavior in order to have a comprehensive framework aimed at potential technological applications. Nowadays, it is well known that the best Al-based amorphous alloys are formed in ternary systems such as Al- RE-TM, where RE is a rare earth and TM a transition metal. This paper presents results of research in Al{sub 85}Ni{sub 10}RE{sub 5} alloys (RE = Y, Gd and Sm). Amorphous ribbons were processed by melt-spinning under the same conditions and subsequently characterized by x-ray diffraction (XRD) and differential scanning calorimetry (DSC). Results show appreciable micro structural differences as function of the rare earth, thus crystal is obtained for Y, nano-glassy for Gd and, fully amorphous structure for Sm. (author)

  15. REPRESENTATION OF JAPANESE POST-COLONIAL EXPERIENCE IN THE YEAR OF 1942-1945 BASED ON PRAMOEDYA ANANTA TOER’S NOVEL “PERBURUAN”

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    Rifqia Kartika Ningrum

    2017-09-01

    Full Text Available This article is aimed to describe post-colonial forms which represented by the figures in the Pramoedya Ananta Toer’s novel Perburuan. This novel portrays about a character named Hardo who fought Japanese colonialism together with his two friends, Dipo and Karmin. However, their plan was failed to be implemented. It was making Hardo a Japanese fugitive. This novel is about the history of Japanese colonialism in Indonesia. Therefore, this novel can be studied with post-colonial theory. Type of this research is descriptive qualitative research using post-colonial approach. Researchers gathered the data by searching data in the novel that has relevance to the three formulations of the post-colonial theory that have been found. These three formulations include resistance, betrayal, and character’s self-doubt (ambivalence. The technique used in this article is content analysis. The research steps were determined the data source, collection the data, classification the data, and data analysis. Data analysis technique used was Miles and Huberman model that consists of data reduction, data presentation, and drawing conclusions. Through the representation of characters in the novel found the forms of resistance, betrayal, and characteristic’s self-doubts as forms of post-colonial representation.

  16. Characterization of rabies virus isolated from a colony of Eptesicus furinalis bats in Brazil

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    Marilene Fernandes de Almeida

    2011-02-01

    Full Text Available Some bat species have adapted to the expanding human population by acquiring the ability to roost in urban buildings, increasing the exposure risk for people and domestic animals, and consequently, the likelihood of transmitting rabies. Three dead bats were found in the yard of a house in an urban area of Jundiaí city in the state of São Paulo in southeast Brazil. Two of the three bats tested positive for rabies, using Fluorescent Antibody and Mouse Inoculation techniques. A large colony of Eptesicus furinalis was found in the house's attic, and of the 119 bats captured, four more tested positive for rabies. The objectives of this study were to report the rabies diagnosis, characterize the isolated virus antigenically and genetically, and study the epidemiology of the colony.

  17. ACOustic: A Nature-Inspired Exploration Indicator for Ant Colony Optimization

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    Rafid Sagban

    2015-01-01

    Full Text Available A statistical machine learning indicator, ACOustic, is proposed to evaluate the exploration behavior in the iterations of ant colony optimization algorithms. This idea is inspired by the behavior of some parasites in their mimicry to the queens’ acoustics of their ant hosts. The parasites’ reaction results from their ability to indicate the state of penetration. The proposed indicator solves the problem of robustness that results from the difference of magnitudes in the distance’s matrix, especially when combinatorial optimization problems with rugged fitness landscape are applied. The performance of the proposed indicator is evaluated against the existing indicators in six variants of ant colony optimization algorithms. Instances for travelling salesman problem and quadratic assignment problem are used in the experimental evaluation. The analytical results showed that the proposed indicator is more informative and more robust.

  18. Ant- and Ant-Colony-Inspired ALife Visual Art.

    Science.gov (United States)

    Greenfield, Gary; Machado, Penousal

    2015-01-01

    Ant- and ant-colony-inspired ALife art is characterized by the artistic exploration of the emerging collective behavior of computational agents, developed using ants as a metaphor. We present a chronology that documents the emergence and history of such visual art, contextualize ant- and ant-colony-inspired art within generative art practices, and consider how it relates to other ALife art. We survey many of the algorithms that artists have used in this genre, address some of their aims, and explore the relationships between ant- and ant-colony-inspired art and research on ant and ant colony behavior.

  19. Improved Ant Colony Clustering Algorithm and Its Performance Study

    Science.gov (United States)

    Gao, Wei

    2016-01-01

    Clustering analysis is used in many disciplines and applications; it is an important tool that descriptively identifies homogeneous groups of objects based on attribute values. The ant colony clustering algorithm is a swarm-intelligent method used for clustering problems that is inspired by the behavior of ant colonies that cluster their corpses and sort their larvae. A new abstraction ant colony clustering algorithm using a data combination mechanism is proposed to improve the computational efficiency and accuracy of the ant colony clustering algorithm. The abstraction ant colony clustering algorithm is used to cluster benchmark problems, and its performance is compared with the ant colony clustering algorithm and other methods used in existing literature. Based on similar computational difficulties and complexities, the results show that the abstraction ant colony clustering algorithm produces results that are not only more accurate but also more efficiently determined than the ant colony clustering algorithm and the other methods. Thus, the abstraction ant colony clustering algorithm can be used for efficient multivariate data clustering. PMID:26839533

  20. Neonicotinoid pesticides can reduce honeybee colony genetic diversity.

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    Nadège Forfert

    Full Text Available Neonicotinoid insecticides can cause a variety of adverse sub-lethal effects in bees. In social species such as the honeybee, Apis mellifera, queens are essential for reproduction and colony functioning. Therefore, any negative effect of these agricultural chemicals on the mating success of queens may have serious consequences for the fitness of the entire colony. Queens were exposed to the common neonicotinoid pesticides thiamethoxam and clothianidin during their developmental stage. After mating, their spermathecae were dissected to count the number of stored spermatozoa. Furthermore, their worker offspring were genotyped with DNA microsatellites to determine the number of matings and the genotypic composition of the colony. Colonies providing the male mating partners were also inferred. Both neonicotinoid and control queens mated with drones originating from the same drone source colonies, and stored similar number of spermatozoa. However, queens reared in colonies exposed to both neonicotinoids experienced fewer matings. This resulted in a reduction of the genetic diversity in their colonies (i.e. higher intracolonial relatedness. As decreased genetic diversity among worker bees is known to negatively affect colony vitality, neonicotinoids may have a cryptic effect on colony health by reducing the mating frequency of queens.

  1. Laser-induced speckle scatter patterns in Bacillus colonies

    Directory of Open Access Journals (Sweden)

    Huisung eKim

    2014-10-01

    Full Text Available Label-free bacterial colony phenotyping technology called BARDOT (BActerial Rapid Detection using Optical scattering Technology provided successful classification of several different bacteria at the genus, species, and serovar level. Recent experiments with colonies of Bacillus species provided strikingly different characteristics of elastic light scatter (ELS patterns, which were comprised of random speckles compared to other bacteria, which are dominated by concentric rings and spokes. Since this laser-based optical sensor interrogates the whole volume of the colony, 3-D information of micro- and macro-structures are all encoded in the far-field scatter patterns. Here, we present a theoretical model explaining the underlying mechanism of the speckle formation by the colonies from Bacillus species. Except for Bacillus polymyxa, all Bacillus spp. produced random bright spots on the imaging plane, which presumably dependent on the cellular and molecular organization and content within the colony. Our scatter model-based analysis revealed that colony spread resulting in variable surface roughness can modify the wavefront of the scatter field. As the center diameter of the Bacillus spp. colony grew from 500 μm to 900 μm, average speckles area decreased 2-fold and the number of small speckles increased 7-fold. In conclusion, as Bacillus colony grows, the average speckle size in the scatter pattern decreases and the number of smaller speckle increases due to the swarming growth characteristics of bacteria within the colony.

  2. Enhancement of erythroid colony growth in culture by hemin

    International Nuclear Information System (INIS)

    Porter, P.N.; Meints, R.H.; Mesner, K.

    1979-01-01

    Hemin was found to enhance the growth of murine erythroid colonies in culture. In the presence of 100 mU/ml erythropoietin (EPO), the addition of hemin (0.05-0.2 mM) resulted in the growth of twice as many colonies as were obtained with EPO alone. Hemin also significantly increased erythroid colony formation in culture in the absence of added EPO. Hemoblobin synthesis as measured by the incorporation of 59 Fe into cyclohexanone extractable heme was augmented in culture by hemin. Neither Δ-aminolevulinic acid, a hemin precursor, nor FeCl 3 increased colony number. (author)

  3. Rethinking the Colonial State: Configurations of Power, Violence, and Agency

    DEFF Research Database (Denmark)

    Rud, Søren; Ivarsson, Søren

    2017-01-01

    The main theme of this special volume is the colonial state and its governmental practices. This chapter introduces and contextualizes the contributions by providing a brief induction to recent developments within the study of the colonial state. It then presents the contributions under three per...... perspectives which represent separate yet interrelated themes relevant for the understanding of the colonial state: practices, violence, and agency. Hereby, we also accentuate the value of a non-state-centric approach to the analysis of the colonial state....

  4. Leukemic blast cell colony formation in semisolid culture with erythropoietin: a case report of acute poorly differentiated erythroid leukemia.

    Science.gov (United States)

    Tomonaga, M; Jinnai, I; Tagawa, M; Amenomori, T; Nishino, K; Yao, E; Nonaka, H; Kuriyama, K; Yoshida, Y; Matsuo, T

    1987-02-01

    The bone marrow of a patient with acute undifferentiated leukemia developed unique colonies after a 14-day culture in erythropoietin (EPO)-containing methylcellulose. The colonies consisted of 20 to 200 nonhemoglobinized large blast cells. Cytogenetic analysis of single colonies revealed hypotetraploid karyotypes with several marker chromosomes that were identical to those found in directly sampled bone marrow. The concurrently formed erythroid bursts showed only normal karyotypes. No leukemic colony formation was observed in other culture systems with either colony-stimulating activity (CSA) or phytohemagglutinin-stimulated leukocyte-conditioned medium (PHA-LCM). The leukemic colonies exhibited a complete EPO-dose dependency similar to that of the patient's normal BFU-E. Although cytochemical and immunologic marker studies of the bone marrow cells failed to clarify the cell lineage of the leukemic cells with extraordinarily large cell size, ultrastructural study revealed erythroid differentiation such as siderosome formation in the cytoplasm and ferritin particles in the rhophecytosis invaginations. These findings indicate that the patient had poorly differentiated erythroid leukemia and that some of the clonogenic cells might respond to EPO in vitro. Corresponding to this biological feature, the leukemic cells were markedly decreased in number in response to repeated RBC transfusions, and partial remission was obtained. These observations suggest that erythroid leukemia distinct from erythroleukemia (M6) with a myeloblastic component, can develop as a minor entity of human acute leukemia.

  5. Elimination of field colonies of a mound-building termite Globitermes sulphureus (Isoptera: Termitidae) by bistrifluron bait.

    Science.gov (United States)

    Neoh, Kok-Boon; Jalaludin, Nur Atiqah; Lee, Chow-Yang

    2011-04-01

    The efficacy of Xterm, which contains 1% bistrifluron, in the form of cellulose bait pellets was evaluated for its efficacy in eradicating field colonies of the mound-building termite Globitermes sulphureus (Haviland) (Isoptera: Termitidae). The termite mounds were dissected at the end of the experiment to determine whether the colonies were eliminated. By approximately 2 mo postbaiting, the body of termite workers appeared marble white, and mites were present on the body. The soldier-worker ratio increased drastically in the colonies, and the wall surface of the mounds started to erode. Colony elimination required at least a 4-mo baiting period. Mound dissection revealed wet carton materials (food store) that were greatly consumed and overgrown by fast-growing fungi. Decaying cadavers were scattered all over the nests. On average, 84.1 +/- 16.4 g of bait matrix (68.9 +/- 13.4%, an equivalent of 841 +/- 164 mg of bistrifluron) was consumed in each colony. Moreover, we found that a mere 143 mg of bistrifluron was sufficient to eliminate a colony of C. sulphureus.

  6. Colony geometry and structural complexity of the endangered species Acropora cervicornis partly explains the structure of their associated fish assemblage.

    Science.gov (United States)

    Agudo-Adriani, Esteban A; Cappelletto, Jose; Cavada-Blanco, Francoise; Croquer, Aldo

    2016-01-01

    In the past decade, significant efforts have been made to describe fish-habitat associations. However, most studies have oversimplified actual connections between fish assemblages and their habitats by using univariate correlations. The purpose of this study was to identify the features of habitat forming corals that facilitate and influences assemblages of associated species such as fishes. For this we developed three-dimensional models of colonies of Acropora cervicornis to estimate geometry (length and height), structural complexity (i.e., volume, density of branches, etc.) and biological features of the colonies (i.e., live coral tissue, algae). We then correlated these colony characteristics with the associated fish assemblage using multivariate analyses. We found that geometry and complexity were better predictors of the structure of fish community, compared to other variables such as percentage of live coral tissue or algae. Combined, the geometry of each colony explained 40% of the variability of the fish assemblage structure associated with this coral species; 61% of the abundance and 69% of fish richness, respectively. Our study shows that three-dimensional reconstructions of discrete colonies of Acropora cervicornis provides a useful description of the colonial structural complexity and may explain a great deal of the variance in the structure of the associated coral reef fish community. This demonstration of the strongly trait-dependent ecosystem role of this threatened species has important implications for restoration and conservation efforts.

  7. Colony geometry and structural complexity of the endangered species Acropora cervicornis partly explains the structure of their associated fish assemblage

    Directory of Open Access Journals (Sweden)

    Esteban A. Agudo-Adriani

    2016-04-01

    Full Text Available In the past decade, significant efforts have been made to describe fish-habitat associations. However, most studies have oversimplified actual connections between fish assemblages and their habitats by using univariate correlations. The purpose of this study was to identify the features of habitat forming corals that facilitate and influences assemblages of associated species such as fishes. For this we developed three-dimensional models of colonies of Acropora cervicornis to estimate geometry (length and height, structural complexity (i.e., volume, density of branches, etc. and biological features of the colonies (i.e., live coral tissue, algae. We then correlated these colony characteristics with the associated fish assemblage using multivariate analyses. We found that geometry and complexity were better predictors of the structure of fish community, compared to other variables such as percentage of live coral tissue or algae. Combined, the geometry of each colony explained 40% of the variability of the fish assemblage structure associated with this coral species; 61% of the abundance and 69% of fish richness, respectively. Our study shows that three-dimensional reconstructions of discrete colonies of Acropora cervicornis provides a useful description of the colonial structural complexity and may explain a great deal of the variance in the structure of the associated coral reef fish community. This demonstration of the strongly trait-dependent ecosystem role of this threatened species has important implications for restoration and conservation efforts.

  8. Detection and quantification of intracellular bacterial colonies by automated, high-throughput microscopy.

    Science.gov (United States)

    Ernstsen, Christina L; Login, Frédéric H; Jensen, Helene H; Nørregaard, Rikke; Møller-Jensen, Jakob; Nejsum, Lene N

    2017-08-01

    To target bacterial pathogens that invade and proliferate inside host cells, it is necessary to design intervention strategies directed against bacterial attachment, cellular invasion and intracellular proliferation. We present an automated microscopy-based, fast, high-throughput method for analyzing size and number of intracellular bacterial colonies in infected tissue culture cells. Cells are seeded in 48-well plates and infected with a GFP-expressing bacterial pathogen. Following gentamicin treatment to remove extracellular pathogens, cells are fixed and cell nuclei stained. This is followed by automated microscopy and subsequent semi-automated spot detection to determine the number of intracellular bacterial colonies, their size distribution, and the average number per host cell. Multiple 48-well plates can be processed sequentially and the procedure can be completed in one working day. As a model we quantified intracellular bacterial colonies formed by uropathogenic Escherichia coli (UPEC) during infection of human kidney cells (HKC-8). Urinary tract infections caused by UPEC are among the most common bacterial infectious diseases in humans. UPEC can colonize tissues of the urinary tract and is responsible for acute, chronic, and recurrent infections. In the bladder, UPEC can form intracellular quiescent reservoirs, thought to be responsible for recurrent infections. In the kidney, UPEC can colonize renal epithelial cells and pass to the blood stream, either via epithelial cell disruption or transcellular passage, to cause sepsis. Intracellular colonies are known to be clonal, originating from single invading UPEC. In our experimental setup, we found UPEC CFT073 intracellular bacterial colonies to be heterogeneous in size and present in nearly one third of the HKC-8 cells. This high-throughput experimental format substantially reduces experimental time and enables fast screening of the intracellular bacterial load and cellular distribution of multiple

  9. Central Asia, Euro-centrism and Colonialism

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    Nargis T. Nurulla-Khodzhaeva

    2015-01-01

    Full Text Available The following article should not be dismissed as yet another attempt to construct a renewed round ofrevisionism in history. On the contrary, it aims to explore the possibility of scaling down the dominant Eurocentric epistemology that served as a basis for a stereotypical frame of knowledge about Central Asia. The majority of researchers of the region do not deem the need to review the scale of contradictory clashes created by the notion of Eurocentrism. The latter is reflected in numerous articles about the frozen (and sadly deadlock dilemma on why and how were the lands of Tajiks, Uzbeks and Kazakhs divided. By publishing conventional analyses on the region's "clumsy separation", experts illustrate their subaltern, narrowly framed by the colonial world, knowledge and hence, remain as gravestones of the Eurocentric methodology. In the process of such explication, the most important role is allocated to the modern culture, which encouraged the formation of the paradox, represented to us via the paraphrased Soviet aphorism: modernity and coloniality are twin brothers. The initiation of the process of decolonizing the mind within the five republics of the region is possible. One of the solutions involves recognizing the integrity of the pluralist-cycled culture and philosophy of the region. The proposed act will allow shrinking the focus on the knowledge within the limited national units and frames (thus, lessening the degree of'fetishism of the national identity', and rather creating conditions for designing the "bridge", linking different cultures, ideologies and institutional spaces in Central Asia, as a transnational intellectual matrix. The aforementioned theory will provide a basis and structure for empirical facts, and, therefore, drive the researchers from merely constituting to critically thinking, and consequently, inspire to come upon new approaches and fields of study, connecting them with the existing, colonial experiences. It is

  10. A economia colonial do Grão-Pará: uma avaliação crítica (1720-1822 The colonial economy of Grão-Pará: a critical evaluation (1720-1822

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    Francisco de Assis Costa

    2012-04-01

    Full Text Available Com base em exaustivo trabalho de reconstituição de séries que se estendem de 1720 a 1822, o artigo objetiva contribuir para a construção de perspectivas da economia colonial amazônica que enfatizem o contexto global - a capacidade demonstrada de se afirmar como subsistema do Império Colonial Português no contexto do mercado mundial. Ao discutir essa capacidade, avalia a evolução das condições fundamentais de escala e eficiência, entendendo-as como determinadas pelas condições locais de operação do projeto colonial. Tais condições, caracterizadas pelos fundamentos naturais únicos do bioma amazônico, são avaliadas na referência das mudanças institucionais que marcam, vigorosamente, no tempo, a trajetória da economia e sociedade regionais.Based on work of restoration of time series of some important economic variables that extend from 1720 to 1822, the paper aims to contribute to a vision of the Amazonian colonial economy that emphasizes the global context - it means a demonstrated ability to assert itself as sub-system of the Portuguese Colonial Empire in the context of world market. In discussing this capacity, the article evaluates the evolution of fundamental conditions of efficiency of the colony, considering them as determined by the peculiar features that assumed the local operation of the colonial project in Grão-Pará. These conditions, strongly characterized by the uniqueness of the natural foundations of the Amazonian biome, are evaluated in reference to the institutional changes that mark in time the trajectory of the regional economy and society.

  11. Area-based cell colony surviving fraction evaluation: A novel fully automatic approach using general-purpose acquisition hardware.

    Science.gov (United States)

    Militello, Carmelo; Rundo, Leonardo; Conti, Vincenzo; Minafra, Luigi; Cammarata, Francesco Paolo; Mauri, Giancarlo; Gilardi, Maria Carla; Porcino, Nunziatina

    2017-10-01

    The current methodology for the Surviving Fraction (SF) measurement in clonogenic assay, which is a technique to study the anti-proliferative effect of treatments on cell cultures, involves manual counting of cell colony forming units. This procedure is operator-dependent and error-prone. Moreover, the identification of the exact colony number is often not feasible due to the high growth rate leading to the adjacent colony merging. As a matter of fact, conventional assessment does not deal with the colony size, which is generally correlated with the delivered radiation dose or the administered cytotoxic agent. Considering that the Area Covered by Colony (ACC) is proportional to the colony number and size as well as to the growth rate, we propose a novel fully automatic approach exploiting Circle Hough Transform, to automatically detect the wells in the plate, and local adaptive thresholding, which calculates the percentage of ACC for the SF quantification. This measurement relies just on this covering percentage and does not consider the colony number, preventing inconsistencies due to intra- and inter-operator variability. To evaluate the accuracy of the proposed approach, we compared the SFs obtained by our automatic ACC-based method against the conventional counting procedure. The achieved results (r = 0.9791 and r = 0.9682 on MCF7 and MCF10A cells, respectively) showed values highly correlated with the measurements using the traditional approach based on colony number alone. The proposed computer-assisted methodology could be integrated in laboratory practice as an expert system for the SF evaluation in clonogenic assays. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Novel Perspectives on the Characterization of Species-Dependent Optical Signatures of Bacterial Colonies by Digital Holography.

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    Igor Buzalewicz

    Full Text Available The use of light diffraction for the microbiological diagnosis of bacterial colonies was a significant breakthrough with widespread implications for the food industry and clinical practice. We previously confirmed that optical sensors for bacterial colony light diffraction can be used for bacterial identification. This paper is focused on the novel perspectives of this method based on digital in-line holography (DIH, which is able to reconstruct the amplitude and phase properties of examined objects, as well as the amplitude and phase patterns of the optical field scattered/diffracted by the bacterial colony in any chosen observation plane behind the object from single digital hologram. Analysis of the amplitude and phase patterns inside a colony revealed its unique optical properties, which are associated with the internal structure and geometry of the bacterial colony. Moreover, on a computational level, it is possible to select the desired scattered/diffracted pattern within the entire observation volume that exhibits the largest amount of unique, differentiating bacterial features. These properties distinguish this method from the already proposed sensing techniques based on light diffraction/scattering of bacterial colonies. The reconstructed diffraction patterns have a similar spatial distribution as the recorded Fresnel patterns, previously applied for bacterial identification with over 98% accuracy, but they are characterized by both intensity and phase distributions. Our results using digital holography provide new optical discriminators of bacterial species revealed in one single step in form of new optical signatures of bacterial colonies: digital holograms, reconstructed amplitude and phase patterns, as well as diffraction patterns from all observation space, which exhibit species-dependent features. To the best of our knowledge, this is the first report on bacterial colony analysis via digital holography and our study represents an

  13. Novel Perspectives on the Characterization of Species-Dependent Optical Signatures of Bacterial Colonies by Digital Holography.

    Science.gov (United States)

    Buzalewicz, Igor; Kujawińska, Małgorzata; Krauze, Wojciech; Podbielska, Halina

    2016-01-01

    The use of light diffraction for the microbiological diagnosis of bacterial colonies was a significant breakthrough with widespread implications for the food industry and clinical practice. We previously confirmed that optical sensors for bacterial colony light diffraction can be used for bacterial identification. This paper is focused on the novel perspectives of this method based on digital in-line holography (DIH), which is able to reconstruct the amplitude and phase properties of examined objects, as well as the amplitude and phase patterns of the optical field scattered/diffracted by the bacterial colony in any chosen observation plane behind the object from single digital hologram. Analysis of the amplitude and phase patterns inside a colony revealed its unique optical properties, which are associated with the internal structure and geometry of the bacterial colony. Moreover, on a computational level, it is possible to select the desired scattered/diffracted pattern within the entire observation volume that exhibits the largest amount of unique, differentiating bacterial features. These properties distinguish this method from the already proposed sensing techniques based on light diffraction/scattering of bacterial colonies. The reconstructed diffraction patterns have a similar spatial distribution as the recorded Fresnel patterns, previously applied for bacterial identification with over 98% accuracy, but they are characterized by both intensity and phase distributions. Our results using digital holography provide new optical discriminators of bacterial species revealed in one single step in form of new optical signatures of bacterial colonies: digital holograms, reconstructed amplitude and phase patterns, as well as diffraction patterns from all observation space, which exhibit species-dependent features. To the best of our knowledge, this is the first report on bacterial colony analysis via digital holography and our study represents an innovative approach

  14. Development of arithmetical abilities

    Directory of Open Access Journals (Sweden)

    Tatjana Levstek

    2014-02-01

    Full Text Available Arithmetic (from the word 'arithmos' which means 'numbers' is an elementary branch of mathematics. Numeracy is essential for understanding mathematics, so the development of arithmetic abilities has been an area of scientific research for a long time. Recent research has shown that the development of arithmetic abilities is not based only on gaining experience and learning. Some arithmetic abilities, especially the sense of quantity, are innate. Even babies are able to distinguish between groups with different number of elements and they perceive numeracy amodally. Six-month-olds distinguish between two groups with the numeracy ratio of 1 : 2. With age this ratio improves rapidly. Five-year-old children already distinguish between groups with the number ratio 7 : 8. The ability to compare two quantities begins to develop after 15 months of age and children learn how to count spontaneously, together with the acquisition of language. Speech enables children to understand number in its abstract, symbolic sense, thus opening the way to symbolic arithmetic. During the preschool period children use intuition when doing calculations, but in school the arithmetic is based on the knowledge of arithmetical algorithms. So, in order to acquire mathematical knowledge, it is necessary to incorporate memory and automate arithmetical processes, without the use of intuition. However, research has shown that intuition is very important and is even a predictive factor for the development of mathematical abilities throughout the schooling process.

  15. PinaColada: peptide-inhibitor ant colony ad-hoc design algorithm.

    Science.gov (United States)

    Zaidman, Daniel; Wolfson, Haim J

    2016-08-01

    Design of protein-protein interaction (PPI) inhibitors is a major challenge in Structural Bioinformatics. Peptides, especially short ones (5-15 amino acid long), are natural candidates for inhibition of protein-protein complexes due to several attractive features such as high structural compatibility with the protein binding site (mimicking the surface of one of the proteins), small size and the ability to form strong hotspot binding connections with the protein surface. Efficient rational peptide design is still a major challenge in computer aided drug design, due to the huge space of possible sequences, which is exponential in the length of the peptide, and the high flexibility of peptide conformations. In this article we present PinaColada, a novel computational method for the design of peptide inhibitors for protein-protein interactions. We employ a version of the ant colony optimization heuristic, which is used to explore the exponential space ([Formula: see text]) of length n peptide sequences, in combination with our fast robotics motivated PepCrawler algorithm, which explores the conformational space for each candidate sequence. PinaColada is being run in parallel, on a DELL PowerEdge 2.8 GHZ computer with 20 cores and 256 GB memory, and takes up to 24 h to design a peptide of 5-15 amino acids length. An online server available at: http://bioinfo3d.cs.tau.ac.il/PinaColada/. danielza@post.tau.ac.il; wolfson@tau.ac.il. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  16. SigB is a dominant regulator of virulence in Staphylococcus aureus small-colony variants.

    Science.gov (United States)

    Mitchell, Gabriel; Fugère, Alexandre; Pépin Gaudreau, Karine; Brouillette, Eric; Frost, Eric H; Cantin, André M; Malouin, François

    2013-01-01

    Staphylococcus aureus small-colony variants (SCVs) are persistent pathogenic bacteria characterized by slow growth and, for many of these strains, an increased ability to form biofilms and to persist within host cells. The virulence-associated gene expression profile of SCVs clearly differs from that of prototypical strains and is often influenced by SigB rather than by the agr system. One objective of this work was to confirm the role of SigB in the control of the expression of virulence factors involved in biofilm formation and intracellular persistence of SCVs. This study shows that extracellular proteins are involved in the formation of biofilm by three SCV strains, which, additionally, have a low biofilm-dispersing activity. It was determined that SigB activity modulates biofilm formation by strain SCV CF07-S and is dominant over that of the agr system without being solely responsible for the repression of proteolytic activity. On the other hand, the expression of fnbA and the control of nuclease activity contributed to the SigB-dependent formation of biofilm of this SCV strain. SigB was also required for the replication of CF07-S within epithelial cells and may be involved in the colonization of lungs by SCVs in a mouse infection model. This study methodically investigated SigB activity and associated mechanisms in the various aspects of SCV pathogenesis. Results confirm that SigB activity importantly influences the production of virulence factors, biofilm formation and intracellular persistence for some clinical SCV strains.

  17. Stages of Colonialism in Africa: From Occupation of Land to Occupation of Being

    Directory of Open Access Journals (Sweden)

    Hussein A. Bulhan

    2015-08-01

    Full Text Available This paper draws primarily on my own scholarship, supplemented by the limited academic resources available in the “peripheries” of the world where I live and work (namely, Somali society and Darfur, Sudan, to consider the relationship between colonialism and psychology. I first consider the history of psychology in justifying and bolstering oppression and colonialism. I then consider the ongoing intersection of colonialism and psychology in the form of metacolonialism (or coloniality. I end with thoughts about decolonizing psychological science in teaching, social, and clinical practice. To decolonize psychological science, it is necessary to transform its focus from promotion of individual happiness to cultivation of collective well-being, from a concern with instinct to promotion of human needs, from prescriptions for adjustment to affordances for empowerment, from treatment of passive victims to creation of self-determining actors, and from globalizing, top-down approaches to context-sensitive, bottom-up approaches. Only then will the field realize its potential to advance Frantz Fanon’s call for humane and just social order.

  18. Virtual Archaeology in an argentina colonial estancia

    Directory of Open Access Journals (Sweden)

    Florencia Vázquez

    2014-05-01

    Full Text Available This is a first approach to the application of virtual reconstruction techniques of a colonial house. In Argentina it is still uncommon to perform 3D modeling of archaeological sites and especially in historical archeology. As a first step, we used the Google SketchUp to model the country house located on the banks of the Río de la Plata (Buenos Aires. It has historical significance because it belonged to a Spanish councilman, housed hundreds of slaves and was the place where stayed the troops that carried out the Second British Invasion of Buenos Aires. In this case, the 3D modeling was useful for evaluating the future excavationa and activities of preservation of cultural heritage.

  19. Optic disc detection using ant colony optimization

    Science.gov (United States)

    Dias, Marcy A.; Monteiro, Fernando C.

    2012-09-01

    The retinal fundus images are used in the treatment and diagnosis of several eye diseases, such as diabetic retinopathy and glaucoma. This paper proposes a new method to detect the optic disc (OD) automatically, due to the fact that the knowledge of the OD location is essential to the automatic analysis of retinal images. Ant Colony Optimization (ACO) is an optimization algorithm inspired by the foraging behaviour of some ant species that has been applied in image processing for edge detection. Recently, the ACO was used in fundus images to detect edges, and therefore, to segment the OD and other anatomical retinal structures. We present an algorithm for the detection of OD in the retina which takes advantage of the Gabor wavelet transform, entropy and ACO algorithm. Forty images of the retina from DRIVE database were used to evaluate the performance of our method.

  20. Modelling the morphology of migrating bacterial colonies

    Science.gov (United States)

    Nishiyama, A.; Tokihiro, T.; Badoual, M.; Grammaticos, B.

    2010-08-01

    We present a model which aims at describing the morphology of colonies of Proteus mirabilis and Bacillus subtilis. Our model is based on a cellular automaton which is obtained by the adequate discretisation of a diffusion-like equation, describing the migration of the bacteria, to which we have added rules simulating the consolidation process. Our basic assumption, following the findings of the group of Chuo University, is that the migration and consolidation processes are controlled by the local density of the bacteria. We show that it is possible within our model to reproduce the morphological diagrams of both bacteria species. Moreover, we model some detailed experiments done by the Chuo University group, obtaining a fine agreement.

  1. Dynamics of the Presence of Israeli Acute Paralysis Virus in Honey Bee Colonies with Colony Collapse Disorder

    Directory of Open Access Journals (Sweden)

    Chunsheng Hou

    2014-05-01

    Full Text Available The determinants of Colony Collapse Disorder (CCD, a particular case of collapse of honey bee colonies, are still unresolved. Viruses including the Israeli acute paralysis virus (IAPV were associated with CCD. We found an apiary with colonies showing typical CCD characteristics that bore high loads of IAPV, recovered some colonies from collapse and tested the hypothesis if IAPV was actively replicating in them and infectious to healthy bees. We found that IAPV was the dominant pathogen and it replicated actively in the colonies: viral titers decreased from April to September and increased from September to December. IAPV extracted from infected bees was highly infectious to healthy pupae: they showed several-fold amplification of the viral genome and synthesis of the virion protein VP3. The health of recovered colonies was seriously compromised. Interestingly, a rise of IAPV genomic copies in two colonies coincided with their subsequent collapse. Our results do not imply IAPV as the cause of CCD but indicate that once acquired and induced to replication it acts as an infectious factor that affects the health of the colonies and may determine their survival. This is the first follow up outside the US of CCD-colonies bearing IAPV under natural conditions.

  2. Hierarchical Artificial Bee Colony Algorithm for RFID Network Planning Optimization

    Directory of Open Access Journals (Sweden)

    Lianbo Ma

    2014-01-01

    Full Text Available This paper presents a novel optimization algorithm, namely, hierarchical artificial bee colony optimization, called HABC, to tackle the radio frequency identification network planning (RNP problem. In the proposed multilevel model, the higher-level species can be aggregated by the subpopulations from lower level. In the bottom level, each subpopulation employing the canonical ABC method searches the part-dimensional optimum in parallel, which can be constructed into a complete solution for the upper level. At the same time, the comprehensive learning method with crossover and mutation operators is applied to enhance the global search ability between species. Experiments are conducted on a set of 10 benchmark optimization problems. The results demonstrate that the proposed HABC obtains remarkable performance on most chosen benchmark functions when compared to several successful swarm intelligence and evolutionary algorithms. Then HABC is used for solving the real-world RNP problem on two instances with different scales. Simulation results show that the proposed algorithm is superior for solving RNP, in terms of optimization accuracy and computation robustness.

  3. Hierarchical artificial bee colony algorithm for RFID network planning optimization.

    Science.gov (United States)

    Ma, Lianbo; Chen, Hanning; Hu, Kunyuan; Zhu, Yunlong

    2014-01-01

    This paper presents a novel optimization algorithm, namely, hierarchical artificial bee colony optimization, called HABC, to tackle the radio frequency identification network planning (RNP) problem. In the proposed multilevel model, the higher-level species can be aggregated by the subpopulations from lower level. In the bottom level, each subpopulation employing the canonical ABC method searches the part-dimensional optimum in parallel, which can be constructed into a complete solution for the upper level. At the same time, the comprehensive learning method with crossover and mutation operators is applied to enhance the global search ability between species. Experiments are conducted on a set of 10 benchmark optimization problems. The results demonstrate that the proposed HABC obtains remarkable performance on most chosen benchmark functions when compared to several successful swarm intelligence and evolutionary algorithms. Then HABC is used for solving the real-world RNP problem on two instances with different scales. Simulation results show that the proposed algorithm is superior for solving RNP, in terms of optimization accuracy and computation robustness.

  4. Reinventing the Wheel: The Economic Benefits of Wheeled Transportation in Early British Colonial West Africa

    OpenAIRE

    Isaías N. Chaves; Stanley L. Engerman; James A. Robinson

    2013-01-01

    One of the great puzzles of Sub-Saharan African economic history is that wheeled transportation was barely used prior to the colonial period. Instead, head porterage was the main method of transportation. The consensus among historians is that this was a rational adaption to the underlying conditions and factor endowments. In this paper we undertake the first systematic investigation of the relative costs of the different forms of wheeled transportation in Africa. We focus on calculating the ...

  5. Yeast Colonies: A Model for Studies of Aging, Environmental Adaptation, and Longevity

    OpenAIRE

    Libuše Váchová; Michal Čáp; Zdena Palková

    2012-01-01

    When growing on solid surfaces, yeast, like other microorganisms, develops organized multicellular populations (colonies and biofilms) that are composed of differentiated cells with specialized functions. Life within these populations is a prevalent form of microbial existence in natural settings that provides the cells with capabilities to effectively defend against environmental attacks as well as efficiently adapt and survive long periods of starvation and other stresses. Under such circum...

  6. BETWEEN MEN OF KNOWLEDGE, LETTERS AND SCIENCE: doctors and other curators in colonial Brazil

    Directory of Open Access Journals (Sweden)

    Ana Carolina de Carvalho Viotti

    2014-06-01

    Full Text Available In the centuries before the establishment of Portuguese court and, with them, the teaching and practice of essentially medicalactions in Brazil, there were many people and intercrossed understandingsurrounding the healing practices. In this article, the formation of therapeutic cognizance in the colonial scenario will be examined, a kind of knowledge which only could be formed by the interchange of ideas from the “Old World” and the needs – and possibilities – in the tropics.

  7. Priming Ability Emotional Intelligence

    Science.gov (United States)

    Schutte, Nicola S.; Malouff, John M.

    2012-01-01

    Two studies examined whether priming self-schemas relating to successful emotional competency results in better emotional intelligence performance. In the first study participants were randomly assigned to a successful emotional competency self-schema prime condition or a control condition and then completed an ability measure of emotional…

  8. BIBLIOGRAPHY ON MENTAL ABILITY.

    Science.gov (United States)

    Harvard Univ., Cambridge, MA. Graduate School of Education.

    THIS BIBLIOGRAPHY LISTS MATERIAL ON VARIOUS ASPECTS OF HUMAN INTELLECT. APPROXIMATELY 50 UNANNOTATED REFERENCES ARE PROVIDED TO DOCUMENTS DATING FROM 1955 TO 1966. BOOKS, REPORTS, JOURNAL MATERIALS, AND SOME UNPUBLISHED TITLES ARE LISTED. SUBJECT AREAS INCLUDED ARE (1) INTELLECTUAL DEVELOPMENT, (2) ABILITY DIFFERENCES BETWEEN INDIVIDUALS, RACES,…

  9. Conservatism and Cognitive Ability

    Science.gov (United States)

    Stankov, Lazar

    2009-01-01

    Conservatism and cognitive ability are negatively correlated. The evidence is based on 1254 community college students and 1600 foreign students seeking entry to United States' universities. At the individual level of analysis, conservatism scores correlate negatively with SAT, Vocabulary, and Analogy test scores. At the national level of…

  10. Synchronization of Mental Abilities

    NARCIS (Netherlands)

    Guney, A.

    2008-01-01

    I think it is better to summarize some cognitive issues in relation to this subject; how we learn, how we should organize learning (instructions), knowledge, etc. before treating creativity and rationality. Is it, really, possible to consider creativity without any kind of involvement of the ability

  11. AgrAbility Project

    Science.gov (United States)

    ... Cordless Ratchet Wrench ClampTite Wire Clamping Tool iBlue Smart Gate/Door Opener Full Toolbox AT Database Extranet ... in-person NTW - March 19-22, Portland, Maine House and Senate Appropriations Committees recommend restoring AgrAbility funding... ...

  12. Between Past and Present: The Sociopsychological Constructs of Colonialism, Coloniality and Postcolonialism.

    Science.gov (United States)

    Tomicic, Ana; Berardi, Filomena

    2018-03-01

    If one of the major aspirations of postcolonial theory is to re-establish a balance in the relationship between the (former) colonizer and the colonized by engaging the voices of the "subaltern", and on the other hand to illuminate how power relations of the present are embedded in history (Mills 2007), we argue that important theoretical insights might inform research by anchoring post-colonial theory within a sociopsychological framework. While there is a growing corpus of sociopsychological research articles focusing on how major geopolitical events and historical processes bear on people's lives, we aim to investigate the theoretical potential of postcolonial theory within the disciplines aiming at a sociopsychological approach. By focusing on the social dynamics of power imbalances, post-colonial theory finds its operational meaning: the feelings stemming from actions committed in the past are indeed crucial in determining reparatory attitudes and policies towards members of former colonized groups. Firstly, drawing from the sociopsychological scientific production related to consequences of colonial past, seen in recent years as a growing research interest in the field, we will explore patterns and trends through a thematic analysis of literature. Social Psychology as well as adjacent disciplines can greatly benefit from this theoretical fertilization, especially in the way post-colonial ideologies relate to the symbolic promotion versus exclusion of indigenous culture (Sengupta et al., International Journal of Intercultural Relations, 36(4), 506-517, 2012). Furthermore, by comparing and contrasting the ideological cosmologies relating to this particular topic, this study aims to establish the state of knowledge in the field, to identify how research methods and thematic fields are paired, to find "gaps" and create spaces for research that become integrative of postcolonial theory. While focusing on academic production, we also hope to contribute to develop

  13. Colonial Modernity and the African Worldview: Theorising and ...

    African Journals Online (AJOL)

    concept of hegemony and Jean and John Comaroff's concept of cultural and colonial encounters are used to assist in teasing out deeper meaning in the encounter between the Ndebele and the early Christian missionaries prior to inscription of settler colonialism in the area lying between the Limpopo and Zambezi Rivers.

  14. Embodying colonial photography: remembering violence in Tabee Toean

    NARCIS (Netherlands)

    Bijl, P.

    2011-01-01

    This article is about bodily interactions with photographs. Taking an interview with a veteran from the Dutch colonial army filmed for the documentary Tabee Toean (1995) as its case study, it focuses on the ways in which this man frames these images of colonial warfare through three types of bodily

  15. Mass spectral molecular networking of living microbial colonies

    NARCIS (Netherlands)

    Watrous, J.; Roach, P.; Alexandrov, T.; Heath, B.S.; Yang, J.Y.; Kersten, R.D.; Voort, van der M.; Pogliano, K.; Gross, H.; Raaijmakers, J.; Moore, B.S.; Laskin, J.; Bandeira, N.; Dorrestein, P.C.

    2012-01-01

    Integrating the governing chemistry with the genomics and phenotypes of microbial colonies has been a “holy grail” in microbiology. This work describes a highly sensitive, broadly applicable, and cost-effective approach that allows metabolic profiling of live microbial colonies directly from a Petri

  16. Colony differences in termiticide transfer studies, a role for behavior?

    Science.gov (United States)

    Thomas Shelton

    2010-01-01

    Donor-recipient termiticide transfer laboratory tests were performed by using destructive sampling with two delayed-action non-repellent (DANR) termiticides against each of three colonies of Reticulitermes flavipes (Kollar). Two of the three colonies showed no response to indoxacarb, but all three showed a response to chlorantraniliprole. These results indicate that...

  17. Occurrence of Nosema species in honey bee colonies in Kenya ...

    African Journals Online (AJOL)

    While honey bee colonies in North America and Europe are in decline due to parasites and ... Infections levels were higher in the coastal region than in the interior. ... of the impact of this pathogen to the Kenyan honey bee colonies with a view of ... Senegal (6); Sierra Leone (1); South Africa (96); South Sudan (1); Sudan (3) ...

  18. Colony strength and queen replacement in Melipona marginata (Apidae: Meliponini

    Directory of Open Access Journals (Sweden)

    A. de M. P. Kleinert

    Full Text Available Physogastric queens of Melipona marginata were removed from their colonies in order to verify the acceptance of a new queen by workers. Colony strength was evaluated according to queen oviposition rate and comb diameters. Replacement was observed seven times. Its occurrence and speed related positively to colony strength, independently of queen's age. In weak colonies, queen replacement was observed only once, following colony population increase that occurred after introduction of combs from another colony. Worker oviposition after queen removal was observed three times: in a strong colony with virgin queens and males, and in two of the weak colonies. In the first two or three days of new queen oviposition, during which most of the eggs were eaten by the queen, worker oviposition preceded almost all provisioning and oviposition processes (POPs. After this period, worker oviposition decreased until it reached around 25% of the POPs. Daily oviposition rate of young queens decreased or was even interrupted by hatching of their first brood.

  19. Cormorants as visitors in the Vorsø colony

    DEFF Research Database (Denmark)

    Bregnballe, Thomas; Vinas, Marta Mas; Gregersen, Jens

    2011-01-01

    Like other seabirds Great Cormorants Phalacrocorax carbo sinensis are known to prospect in potential breeding colonies during their first years of life before they settle to breed. Based on daily resightings of colour-ringed cormorants in the old Vorsø colony we examined the difference between...

  20. Colonial Military Intelligence in the Zulu Rebellion, 1906 | Thompson ...

    African Journals Online (AJOL)

    In the Zulu Rebellion of 1906, the Natal Militia defeated the Zulu rebels without British imperial forces having to intervene in the conflict. The colonial forces were well adapted to the local circumstances, but in one important respect they drew heavily on imperial experience, namely military field intelligence. Colonial military ...