WorldWideScience

Sample records for directional pollen transfer

  1. Pollen irradiation and possible gene transfer in Nicotiana species

    DEFF Research Database (Denmark)

    Engvild, Kjeld Christensen

    1985-01-01

    , and Petunia parodii with irradiated pollen from N. alata and Petunia hybrida showed no evidence of gene transfer, nor did experiments with irradiated mentor pollen. This indicates that gene transfer with irradiated pollen between non-crossing species or between species giving sterile hybrids is probably...

  2. Pollinators, geitonogamy and a model of pollen transfer

    International Nuclear Information System (INIS)

    Di Pasquale, C.

    1995-12-01

    A model of pollination that considers the amount of geitonogamous pollen transfer in different flowers and plants is presented. We assumed in this work self-incompatible plant species and we studied how pollination is affected by different round trips described by pollinator from its nest, taking into account the fraction geitonogamy and the fraction pollen export. A deterministic model and a stochastic model of pollen transfer were developed from which we found that when pollinators describe a uniform sequence (visit the same number of flowers in each plant), individuals receive the maximum outcross pollen or minimum self pollen. That is, from the point of view of fertilization, the optimal number of flowers visited in each plant depends on the number of flowers of the plant, the length of the visit and the number of individuals. (author). 18 refs, 1 fig

  3. An experimental test of whether habitat corridors affect pollen transfer.

    Energy Technology Data Exchange (ETDEWEB)

    Townsend, Patricia A.; Levey, Douglas J.

    2005-02-01

    Abstract. Negative effects of habitat fragmentation are thought to be diminished when habitat patches are joined by a corridor. A key assumption is that corridors facilitate exchange rates of organisms between otherwise isolated patches. If the organisms are pollinators, corridors may be important for maintaining genetically viable populations of the plants that they pollinate. We tested the hypothesis that corridors increase the movement of insect pollinators into patches of habitat and thereby increase pollen transfer for two species of plants, one pollinated by butterflies (Lantana camara) and the other by bees and wasps (Rudbeckia hirta). We worked in an experimental landscape consisting of 40 greater than or equal to 1-ha patches of early-successional habitat in a matrix of forest. Within each of eight experimental units, two patches were connected by a corridor (150 X 25 m), and three were not. Patch shape varied to control for the area added by the presence of a corridor. Differences in patch shape also allowed us to test alternative hypotheses of how corridors might function. The Traditional Corridor Hypothesis posits that corridors increase immigration and emigration by functioning as movement conduits between patches. The Drift Fence Hypothesis posits that corridors function by ‘‘capturing’’ organisms dispersing through the matrix, redirecting them into associated habitat patches. Using fluorescent powder to track pollen, we found that pollen transfer by butterflies between patches connected by a corridor was significantly higher than between unconnected patches (all values mean plus or minus 1 SE: 59% plus or minus 9.2% vs. 25% plus or minus 5.2% of flowers receiving pollen). Likewise, pollen transfer by bees and wasps was significantly higher between connected patches than between unconnected patches (30% plus or minus 4.2% vs. 14.5% plus or minus 2.2%). These results support the Traditional Corridor Hypothesis. There was little support, however

  4. Review of probabilistic pollen-climate transfer methods

    Science.gov (United States)

    Ohlwein, Christian; Wahl, Eugene R.

    2012-01-01

    Pollen-climate transfer methods are reviewed from a Bayesian perspective and with a special focus on the formulation of uncertainties. This approach is motivated by recent developments of spatial multi-proxy Bayesian hierarchical models (BHM), which allow synthesizing local reconstructions from different proxies for a spatially complete picture of past climate. In order to enhance the pollen realism in these models we try to bridge the gap between spatial statistics and paleoclimatology and show how far classical pollen-climate transfer concepts such as regression methods, mutual climatic range, modern analogues, plant functional types, and biomes can be understood in novel ways by refining the data models used in BHMs. As a case study, we discuss modeling of uncertainty by introducing a new probabilistic pollen ratio model, which is a simplified variation of the modern analogue technique (MAT) including the concept of response surfaces and designed for later inclusion in a spatial multiproxy BHM. Applications to fossil pollen data from varved sediments in three nearby lakes in west-central Wisconsin, USA and for a Holocene fossil pollen record from southern California, USA provide local climate reconstructions of summer temperature for the past millennium and the Holocene respectively. The performance of the probabilistic model is generally similar in comparison to MAT-derived reconstructions using the same data. Furthermore, the combination of co-location and precise dating for the three fossil sites in Wisconsin allows us to study the issue of site-specific uncertainty and to test the assumption of ergodicity in a real-world example. A multivariate ensemble kernel dressing approach derived from the post-processing of climate simulations reveals that the overall interpretation based on the individual reconstructions remains essentially unchanged, but the single-site reconstructions underestimate the overall uncertainty.

  5. Transference of genetic information through irradiated pollen

    Energy Technology Data Exchange (ETDEWEB)

    Dryanovska, O A [Bylgarska Akademiya na Naukite, Sofia. Inst. po Genetika

    1983-01-01

    Blossoms are used as mothers of two longistylous with male sterility varieties of Deva and Hera without anthocyan on the stem from L. esculentum (Mill.) (L.), which were pollinated with irradiated dallenform L. peruvianum (L.) with anthocyan on the stem, with 10 AND 200 Kr of gamma-rays, 5 and 10 min from a source of mixed (long and short) UV-rays, at a distance of 20 cm, while the control blossoms were pollinated with a mixture of other cultivated plants. Irradiation with gamma rays was carried out on a gamma device with a dose power of up to 1,500 R/m. The results show that irradiated pollen tube with the male chromatin induces gynogenesis and seconadary diploidization. It is assumed that some of the microfragments irradiated with high doses of radiation contain a functionally active gene or the genes responsible for anthocyan synthesis. These microfragments are capable of combining with the nonirradiated mother chromatin and they become involved and operate in the process of development of the mother sex cells and at the early embryogenesis, as a result of which anthocyan appears in the developing plants.

  6. Transference of genetic information through irradiated pollen

    International Nuclear Information System (INIS)

    Dryanovska, O.A.

    1983-01-01

    Blossoms are used as mothers of two longistylous with male sterility varieties of Deva and Hera without anthocyan on the stem from L. esculentum (Mill.) (L.), which were pollinated with irradiated dallenform L. peruvianum (L.) with anthocyan on the stem, with 10 AND 200 Kr of gamma-rays, 5 and 10 min from a source of mixed (long and short) UV-rays, at a distance of 20 cm, while the control blossoms were pollinated with a mixture of other cultivated plants. Irradiation with gamma rays was carried out on a gamma device with a dose power of up to 1,500 R/m. The results show that irradiated pollen tube with the male chromatin induces gynogenesis and seconadary diploidization. It is assumed that some of the microfragments irradiated with high doses of radiation contain a functionally active gene or the genes responsible for anthocyan synthesis. These microfragments are capable of combining with the nonirradiated mother chromatin and they become involved and operate in the process of development of the mother sex cells and at the early embryogenesis, as a result of which anthocyan appears in the developing plants

  7. Pollen

    Science.gov (United States)

    ... that pollen can also be transported indoors on people and pets. Dry your clothes in an automatic dryer rather ... that pollen can also be transported indoors on people and pets. Dry your clothes in an automatic dryer rather ...

  8. The Impact of the Invasive Alien Plant, Impatiens glandulifera, on Pollen Transfer Networks.

    Directory of Open Access Journals (Sweden)

    Carine Emer

    Full Text Available Biological invasions are a threat to the maintenance of ecological processes, including pollination. Plant-flower visitor networks are traditionally used as a surrogated for pollination at the community level, despite they do not represent the pollination process, which takes place at the stigma of plants where pollen grains are deposited. Here we investigated whether the invasion of the alien plant Impatiens glandulifera (Balsaminaceae affects pollen transfer at the community level. We asked whether more alien pollen is deposited on the stigmas of plants on invaded sites, whether deposition is affected by stigma type (dry, semidry and wet and whether the invasion of I. glandulifera changes the structure of the resulting pollen transfer networks. We sampled stigmas of plants on 10 sites invaded by I. glandulifera (hereafter, balsam and 10 non-invaded control sites. All 20 networks had interactions with balsam pollen, although significantly more balsam pollen was found on plants with dry stigmas in invaded areas. Balsam pollen deposition was restricted to a small subset of plant species, which is surprising because pollinators are known to carry high loads of balsam pollen. Balsam invasion did not affect the loading of native pollen, nor did it affect pollen transfer network properties; networks were modular and poorly nested, both of which are likely to be related to the specificity of pollen transfer interactions. Our results indicate that pollination networks become more specialized when moving from the flower visitation to the level of pollen transfer networks. Therefore, caution is needed when inferring pollination from patterns of insect visitation or insect pollen loads as the relationship between these and pollen deposition is not straightforward.

  9. Pollen

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records of past vegetation and climate derived from pollen found in lake and ocean sediments. Parameter keywords describe what was measured in this data set....

  10. Effect of land uses and wind direction on the contribution of local sources to airborne pollen.

    Science.gov (United States)

    Rojo, Jesús; Rapp, Ana; Lara, Beatriz; Fernández-González, Federico; Pérez-Badia, Rosa

    2015-12-15

    The interpretation of airborne pollen levels in cities based on the contribution of the surrounding flora and vegetation is a useful tool to estimate airborne allergen concentrations and, consequently, to determine the allergy risk for local residents. This study examined the pollen spectrum in a city in central Spain (Guadalajara) and analysed the vegetation landscape and land uses within a radius of 20km in an attempt to identify and locate the origin of airborne pollen and to determine the effect of meteorological variables on pollen emission and dispersal. The results showed that local wind direction was largely responsible for changes in the concentrations of different airborne pollen types. The land uses contributing most to airborne pollen counts were urban green spaces, though only 0.1% of the total surface area studied, and broadleaved forest which covered 5% of the study area. These two types of land use together accounted for 70% of the airborne pollen. Crops, scrubland and pastureland, though covering 80% of the total surface area, contributed only 18.6% to the total pollen count, and this contribution mainly consisted of pollen from Olea and herbaceous plants, including Poaceae, Urticaceae and Chenopodiaceae-Amaranthaceae. Pollen from ornamental species were mainly associated with easterly (Platanus), southerly (Cupressaceae) and westerly (Cupressaceae and Platanus) winds from the areas where the city's largest parks and gardens are located. Quercus pollen was mostly transported by winds blowing in from holm-oak stands on the eastern edge of the city. The highest Populus pollen counts were associated with easterly and westerly winds blowing in from areas containing rivers and streams. The airborne pollen counts generally rose with increasing temperature, solar radiation and hours of sunlight, all of which favour pollen release. In contrast, pollen counts declined with increased relative humidity and rainfall, which hinder airborne pollen transport

  11. Effect of land uses and wind direction on the contribution of local sources to airborne pollen

    International Nuclear Information System (INIS)

    Rojo, Jesús; Rapp, Ana; Lara, Beatriz; Fernández-González, Federico; Pérez-Badia, Rosa

    2015-01-01

    The interpretation of airborne pollen levels in cities based on the contribution of the surrounding flora and vegetation is a useful tool to estimate airborne allergen concentrations and, consequently, to determine the allergy risk for local residents. This study examined the pollen spectrum in a city in central Spain (Guadalajara) and analysed the vegetation landscape and land uses within a radius of 20 km in an attempt to identify and locate the origin of airborne pollen and to determine the effect of meteorological variables on pollen emission and dispersal. The results showed that local wind direction was largely responsible for changes in the concentrations of different airborne pollen types. The land uses contributing most to airborne pollen counts were urban green spaces, though only 0.1% of the total surface area studied, and broadleaved forest which covered 5% of the study area. These two types of land use together accounted for 70% of the airborne pollen. Crops, scrubland and pastureland, though covering 80% of the total surface area, contributed only 18.6% to the total pollen count, and this contribution mainly consisted of pollen from Olea and herbaceous plants, including Poaceae, Urticaceae and Chenopodiaceae–Amaranthaceae. Pollen from ornamental species were mainly associated with easterly (Platanus), southerly (Cupressaceae) and westerly (Cupressaceae and Platanus) winds from the areas where the city's largest parks and gardens are located. Quercus pollen was mostly transported by winds blowing in from holm-oak stands on the eastern edge of the city. The highest Populus pollen counts were associated with easterly and westerly winds blowing in from areas containing rivers and streams. The airborne pollen counts generally rose with increasing temperature, solar radiation and hours of sunlight, all of which favour pollen release. In contrast, pollen counts declined with increased relative humidity and rainfall, which hinder airborne pollen transport

  12. Effect of land uses and wind direction on the contribution of local sources to airborne pollen

    Energy Technology Data Exchange (ETDEWEB)

    Rojo, Jesús; Rapp, Ana; Lara, Beatriz; Fernández-González, Federico; Pérez-Badia, Rosa

    2015-12-15

    The interpretation of airborne pollen levels in cities based on the contribution of the surrounding flora and vegetation is a useful tool to estimate airborne allergen concentrations and, consequently, to determine the allergy risk for local residents. This study examined the pollen spectrum in a city in central Spain (Guadalajara) and analysed the vegetation landscape and land uses within a radius of 20 km in an attempt to identify and locate the origin of airborne pollen and to determine the effect of meteorological variables on pollen emission and dispersal. The results showed that local wind direction was largely responsible for changes in the concentrations of different airborne pollen types. The land uses contributing most to airborne pollen counts were urban green spaces, though only 0.1% of the total surface area studied, and broadleaved forest which covered 5% of the study area. These two types of land use together accounted for 70% of the airborne pollen. Crops, scrubland and pastureland, though covering 80% of the total surface area, contributed only 18.6% to the total pollen count, and this contribution mainly consisted of pollen from Olea and herbaceous plants, including Poaceae, Urticaceae and Chenopodiaceae–Amaranthaceae. Pollen from ornamental species were mainly associated with easterly (Platanus), southerly (Cupressaceae) and westerly (Cupressaceae and Platanus) winds from the areas where the city's largest parks and gardens are located. Quercus pollen was mostly transported by winds blowing in from holm-oak stands on the eastern edge of the city. The highest Populus pollen counts were associated with easterly and westerly winds blowing in from areas containing rivers and streams. The airborne pollen counts generally rose with increasing temperature, solar radiation and hours of sunlight, all of which favour pollen release. In contrast, pollen counts declined with increased relative humidity and rainfall, which hinder airborne pollen

  13. Use of γ-irradiated pollen for the gene transfer in Petunia

    International Nuclear Information System (INIS)

    Andrejchenko, S.V.; Grodzinskij, D.M.

    1986-01-01

    Possibility of using gamma-irradiated pollen for the gene transfer in Petunia is shown. Occurrence of gametic transformation provided not only the gene integration and expression but also their transfer to the daughter generations. The described methodical approach to construction of the plant eucariotic cell genome is based not only on its simplicity but also on the fact that gamma-radiation doses of 1000 Gy and higher have no desorganizing effect on the chromatine structure in such a degree that its transcription activity is completely lost. Besides, selective inactivation of the locus radiation in the pollen genome is much assisted by their different radioresistance. Though the gene transfer by gametic transformation is mostly irregular but its probability may be increased by the correct selection of the pollen irradiation dose in a range in which the growth of pollen tube before ovary is conserved and reparation of one-strand and two-strand DNA breaks preventing chromatine fragmentation is suppressed

  14. Pollination potential of male bumble bees (Bombus impatiens: movement patterns and pollen-transfer efficiency

    Directory of Open Access Journals (Sweden)

    James Thomson

    2010-11-01

    Full Text Available Many plant species rely on female bumble bee workers for pollen transfer. However, male bumble bees, which differ both behaviourally and morphologically from female workers, also visit many species of flowering plants and may transfer pollen differently. Males can outnumber workers on some plants, particularly those that flower late in the season. In laboratory experiments, we compared the movement patterns of male bees and female workers on an artificial flower array. We also compared the pollen transfer efficiency of males and workers foraging on Brassica rapa flowers. Males travelled between patches of flowers more often than workers, which may be an effective method for reducing geitonogamy in plants. Males also had lower foraging rates, longer flower handling time, and transferred more pollen from one B. rapa flower to the next than workers did. These caste-based differences in pollinating behaviour suggest that, under certain circumstances and on a per-visit basis, male bumble bees may be better pollen vectors than female foragers. Furthermore, our results emphasize the need to avoid species-wide generalizations of pollinator effectiveness.

  15. Corolla chirality does not contribute to directed pollen movement in Hypericum perforatum (Hypericaceae): mirror image pinwheel flowers function as radially symmetric flowers in pollination.

    Science.gov (United States)

    Diller, Carolina; Fenster, Charles B

    2016-07-01

    Corolla chirality, the pinwheel arrangement of petals within a flower, is found throughout the core eudicots. In 15 families, different chiral type flowers (i.e., right or left rotated corolla) exist on the same plant, and this condition is referred to as unfixed/enantiomorphic corolla chirality. There are no investigations on the significance of unfixed floral chirality on directed pollen movement even though analogous mirror image floral designs, for example, enantiostyly, has evolved in response to selection to direct pollinator and pollen movement. Here, we examine the role of corolla chirality on directing pollen transfer, pollinator behavior, and its potential influence on disassortative mating. We quantified pollen transfer and pollinator behavior and movement for both right and left rotated flowers in two populations of Hypericum perforatum. In addition, we quantified the number of right and left rotated flowers at the individual level. Pollinators were indifferent to corolla chirality resulting in no difference in pollen deposition between right and left flowers. Corolla chirality had no effect on pollinator and pollen movement between and within chiral morphs. Unlike other mirror image floral designs, corolla chirality appears to play no role in promoting disassortative mating in this species.

  16. Arabidopsis COBRA-LIKE 10, a GPI-anchored protein, mediates directional growth of pollen tubes

    NARCIS (Netherlands)

    Li, S.; Ge, F.R.; Xu, M.; Zhao, X.Y.; Huang, G.Q.; Zhou, L.Z.; Wang, J.G.; Kombrink, A.; McCormick, S.; Zhang, X.S.; Zhang, Y.

    2013-01-01

    Successful reproduction of flowering plants requires constant communication between female tissues and growing pollen tubes. Female cells secrete molecules and peptides as nutrients or guidance cues for fast and directional tube growth, which is executed by dynamic changes of intracellular

  17. Development and testing of transfer functions for generating quantitative climatic estimates from Australian pollen data

    Science.gov (United States)

    Cook, Ellyn J.; van der Kaars, Sander

    2006-10-01

    We review attempts to derive quantitative climatic estimates from Australian pollen data, including the climatic envelope, climatic indicator and modern analogue approaches, and outline the need to pursue alternatives for use as input to, or validation of, simulations by models of past, present and future climate patterns. To this end, we have constructed and tested modern pollen-climate transfer functions for mainland southeastern Australia and Tasmania using the existing southeastern Australian pollen database and for northern Australia using a new pollen database we are developing. After testing for statistical significance, 11 parameters were selected for mainland southeastern Australia, seven for Tasmania and six for northern Australia. The functions are based on weighted-averaging partial least squares regression and their predictive ability evaluated against modern observational climate data using leave-one-out cross-validation. Functions for summer, annual and winter rainfall and temperatures are most robust for southeastern Australia, while in Tasmania functions for minimum temperature of the coldest period, mean winter and mean annual temperature are the most reliable. In northern Australia, annual and summer rainfall and annual and summer moisture indexes are the strongest. The validation of all functions means all can be applied to Quaternary pollen records from these three areas with confidence. Copyright

  18. Gene transfer in Nicotiana rustica by means of irradiated pollen II. Cytogenetical consequences

    International Nuclear Information System (INIS)

    Werner, C.P.; Dunkin, I.M.; Cornish, M.A.; Jones, G.H.

    1984-01-01

    Pollen from Nicotiana paniculata and the V12 variety of N. rustica was irradiated with a range of high doses of gamma-rays up to 100 Krads. Both kinds of pollen were used to pollinate the V27 variety of N. rustica. Radiation treatments above 30 Krads gave no viable seed. A cytological examination of the M 1 progeny from the 20 Krad treatments of both crosses revealed conventional radiation damage in the form of losses of whole chromosomes and parts of chromosomes, and rearrangements. The plants possessed hybrid or aberrantly hybrid phenotypes. It was concluded that they were the products of a conventional fertilisation mechanism rather than the gene transfer mechanism proposed by Pandey (1980). The expression of mutational damage can probably account for most of the maternal trends observed in the intervarietal M 2 of N. rustica examined previously, although post-meiotic selection may also play a role. (author)

  19. Use of irradiated pollen for differential gene transfer in wheat (Triticum aestivum)

    Energy Technology Data Exchange (ETDEWEB)

    Snape, J.W.; Parker, B.B.; Simpson, E.; Ainsworth, C.C.; Payne, P.I.; Law, C.N.

    1983-01-01

    The use of irradiated pollen to bring about limited gene transfer in wheat has been investigated. Doses of X-rays of 2Kr, 3Kr and 5Kr were used to generate M/sub 1/ progeny between maternal and paternal genotypes differing in quantitative and major gene characters. Cytological studies of M/sub 1/ plants revealed hybrids with widespread aneuploidy and structural rearrangements in the paternal genome. These effects resulted in phenotypic variation between M/sub 1/ progeny and complex multivalent formation at meiosis. All M/sub 1/ plants at the 5Kr and 3Kr doses were sterile and all but 2 plants at the 2Kr dose. Studies of the two M/sub 2/ families from these plants revealed disturbances in genotype frequencies for some of the marker loci with an excess of maternal homozygotes and a deficit of paternal homozygotes. This was also reflected in a more maternal appearance for quantitative characters. These results are interpreted as showing that irradiation damage to the paternal genome in M/sub 1/ plants results in the differential transmission of maternal alleles.

  20. The use of irradiated pollen for differential gene transfer in wheat (Triticum aestivum)

    International Nuclear Information System (INIS)

    Snape, J.W.; Parker, B.B.; Simpson, E.; Ainsworth, C.C.; Payne, P.I.; Law, C.N.

    1983-01-01

    The use of irradiated pollen to bring about limited gene transfer in wheat has been investigated. Doses of X-rays of 2Kr, 3Kr and 5Kr were used to generate M 1 progeny between maternal and paternal genotypes differing in quantitative and major gene characters. Cytological studies of M 1 plants revealed hybrids with widespread aneuploidy and structural rearrangements in the paternal genome. These effects resulted in phenotypic variation between M 1 progeny and complex multivalent formation at meiosis. All M 1 plants at the 5Kr and 3Kr doses were sterile and all but 2 plants at the 2Kr dose. Studies of the two M 2 families from these plants revealed disturbances in genotype frequencies for some of the marker loci with an excess of maternal homozygotes and a deficit of paternal homozygotes. This was also reflected in a more maternal appearance for quantitative characters. These results are interpreted as showing that irradiation damage to the paternal genome in M 1 plants results in the differential transmission of maternal alleles. (orig.)

  1. Enantiostyly in Chamaecrista ramosa (Fabaceae-Caesalpinioideae): floral morphology, pollen transfer dynamics and breeding system.

    Science.gov (United States)

    Almeida, N M de; Castro, C C de; Leite, A V de Lima; Novo, R R; Machado, I C

    2013-03-01

    Enantiostyly is a form of reciprocal herkogamy, in which floral morphs present reciprocal differences in the position of sexual elements, and occurs in monomorphic and dimorphic forms. This polymorphism maximises cross-pollination and reduces self-pollination, being very common within the subtribe Cassiinae (Fabaceae). Nevertheless, few studies have investigated the functionality of enantiostyly, particularly in this plant group. The present study aimed to investigate enantiostyly and its functionality in Chamaecrista ramosa, a monomorphic enantiostylous shrub, in an area of coastal vegetation in northeast Brazil. Pollen deposition and capture on the body of floral visitors, the relationship of these data with floral biology and breeding system, and morph ratio were evaluated. Pollen deposition and capture occurred in specific sites of the floral visitor body, showing the functionality of enantiostyly. The floral architecture, associated with the floral visitor behaviour, resulted in indirect pollen deposition on the floral visitor body. This occurred through a loop made by the pollen upon the inner petal surface, similar that generally reported for other Cassiinae. Chamaecrista ramosa is self-compatible, although no fruit set was observed through spontaneous self-pollination. The occurrence and number of floral morphs was similar within clumps. Enantiostyly seems to be advantageous for this species, as it results in efficient pollen capture and deposition, reduces the chances of autogamy and maximises intermorph pollen flow. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

  2. Heat Transfer in Directional Water Transport Fabrics

    Directory of Open Access Journals (Sweden)

    Chao Zeng

    2016-10-01

    Full Text Available Directional water transport fabrics can proactively transfer moisture from the body. They show great potential in making sportswear and summer clothing. While moisture transfer has been previously reported, heat transfer in directional water transport fabrics has been little reported in research literature. In this study, a directional water transport fabric was prepared using an electrospraying technique and its heat transfer properties under dry and wet states were evaluated, and compared with untreated control fabric and the one pre-treated with NaOH. All the fabric samples showed similar heat transfer features in the dry state, and the equilibrium temperature in the dry state was higher than for the wet state. Wetting considerably enhanced the thermal conductivity of the fabrics. Our studies indicate that directional water transport treatment assists in moving water toward one side of the fabric, but has little effect on thermal transfer performance. This study may be useful for development of “smart” textiles for various applications.

  3. Heat transfer direction dependence of heat transfer coefficients in annuli

    Science.gov (United States)

    Prinsloo, Francois P. A.; Dirker, Jaco; Meyer, Josua P.

    2018-04-01

    In this experimental study the heat transfer phenomena in concentric annuli in tube-in-tube heat exchangers at different annular Reynolds numbers, annular diameter ratios, and inlet fluid temperatures using water were considered. Turbulent flow with Reynolds numbers ranging from 15,000 to 45,000, based on the average bulk fluid temperature was tested at annular diameter ratios of 0.327, 0.386, 0.409 and 0.483 with hydraulic diameters of 17.00, 22.98, 20.20 and 26.18 mm respectively. Both heated and cooled annuli were investigated by conducting tests at a range of inlet temperatures between 10 °C to 30 °C for heating cases, and 30 °C to 50 °C for cooling cases. Of special interest was the direct measurement of local wall temperatures on the heat transfer surface, which is often difficult to obtain and evasive in data-sets. Continuous verification and re-evaluation of temperatures measurements were performed via in-situ calibration. It is shown that inlet fluid temperature and the heat transfer direction play significant roles on the magnitude of the heat transfer coefficient. A new adjusted Colburn j-factor definition is presented to describe the heating and cooling cases and is used to correlate the 894 test cases considered in this study.

  4. Direct transfer of graphene onto flexible substrates

    Science.gov (United States)

    Martins, Luiz G. P.; Song, Yi; Zeng, Tingying; Dresselhaus, Mildred S.; Kong, Jing; Araujo, Paulo T.

    2013-01-01

    In this paper we explore the direct transfer via lamination of chemical vapor deposition graphene onto different flexible substrates. The transfer method investigated here is fast, simple, and does not require an intermediate transfer membrane, such as polymethylmethacrylate, which needs to be removed afterward. Various substrates of general interest in research and industry were studied in this work, including polytetrafluoroethylene filter membranes, PVC, cellulose nitrate/cellulose acetate filter membranes, polycarbonate, paraffin, polyethylene terephthalate, paper, and cloth. By comparing the properties of these substrates, two critical factors to ensure a successful transfer on bare substrates were identified: the substrate’s hydrophobicity and good contact between the substrate and graphene. For substrates that do not satisfy those requirements, polymethylmethacrylate can be used as a surface modifier or glue to ensure successful transfer. Our results can be applied to facilitate current processes and open up directions for applications of chemical vapor deposition graphene on flexible substrates. A broad range of applications can be envisioned, including fabrication of graphene devices for opto/organic electronics, graphene membranes for gas/liquid separation, and ubiquitous electronics with graphene. PMID:24127582

  5. Direct transfer of graphene onto flexible substrates.

    Science.gov (United States)

    Martins, Luiz G P; Song, Yi; Zeng, Tingying; Dresselhaus, Mildred S; Kong, Jing; Araujo, Paulo T

    2013-10-29

    In this paper we explore the direct transfer via lamination of chemical vapor deposition graphene onto different flexible substrates. The transfer method investigated here is fast, simple, and does not require an intermediate transfer membrane, such as polymethylmethacrylate, which needs to be removed afterward. Various substrates of general interest in research and industry were studied in this work, including polytetrafluoroethylene filter membranes, PVC, cellulose nitrate/cellulose acetate filter membranes, polycarbonate, paraffin, polyethylene terephthalate, paper, and cloth. By comparing the properties of these substrates, two critical factors to ensure a successful transfer on bare substrates were identified: the substrate's hydrophobicity and good contact between the substrate and graphene. For substrates that do not satisfy those requirements, polymethylmethacrylate can be used as a surface modifier or glue to ensure successful transfer. Our results can be applied to facilitate current processes and open up directions for applications of chemical vapor deposition graphene on flexible substrates. A broad range of applications can be envisioned, including fabrication of graphene devices for opto/organic electronics, graphene membranes for gas/liquid separation, and ubiquitous electronics with graphene.

  6. Transfer of Chernobyl-derived 134Cs, 137Cs, 131I and 103Ru from flowers to honey and pollen

    International Nuclear Information System (INIS)

    Bunzl, K.; Kracke, W.

    1988-01-01

    The activity concentrations of 137 Cs, 134 Cs, 131 I and 103 Ru were determined separately in honey and pollen samples collected from a single bee colony during several months after the deposition of Chernobyl fallout. The source of each honey and pollen sample was determined by pollen analysis. Although the activity concentrations in honey and pollen varied with time, the concentrations of 137 Cs and 134 Cs were, in general, higher in pollen than in honey. For 103 Ru and 131 I, these differences were comparatively small. The mean 131 I/ 137 Cs and 103 Ru/ 137 Cs ratios were about one order of magnitude higher in honey than in pollen. The mean 131 I/ 103 Ru ratio was about the same for honey and pollen. This observation, in the light of the corresponding nuclide ratios found in the deposition, suggests that 137 Cs, 134 Cs, 131 I and 103 Ru were taken up by the plant leaves and transported to nectar and pollen. The higher activity concentrations of 137 Cs and 134 Cs in pollen, relative to honey, indicate that these radionuclides behave analogously to potassium, which is also found in higher quantities in pollen. (author)

  7. Direct electron transfer based enzymatic fuel cells

    International Nuclear Information System (INIS)

    Falk, Magnus; Blum, Zoltan; Shleev, Sergey

    2012-01-01

    In this mini-review we briefly describe some historical developments made in the field of enzymatic fuel cells (FCs), discussing important design considerations taken when constructing mediator-, cofactor-, and membrane-less biological FCs (BFCs). Since the topic is rather extensive, only BFCs utilizing direct electron transfer (DET) reactions on both the anodic and cathodic sides are considered. Moreover, the performance of mostly glucose/oxygen biodevices is analyzed and compared. We also present some unpublished results on mediator-, cofactor-, and membrane-less glucose/oxygen BFCs recently designed in our group and tested in different human physiological fluids, such as blood, plasma, saliva, and tears. Finally, further perspectives for BFC applications are highlighted.

  8. Bee Pollen

    Science.gov (United States)

    ... for nutrition; as an appetite stimulant; to improve stamina and athletic performance; and for premature aging, premenstrual ... use bee pollen as a general tonic, to increase urine flow, and for alcohol intoxication. Bee pollen ...

  9. Heat transfer characteristics of a direct contact heat exchanger

    International Nuclear Information System (INIS)

    Kinoshita, I.; Nishi, Y.

    1993-01-01

    As a first step for development of a direct contact steam generator for FBRs, fundamental heat transfer characteristics of a liquid-liquid contact heat exchanger were evaluated by heat transfer experiment with low melting point alloy and water. Distinctive characteristics of direct contact heat transfer with liquid metal and water was obtained. (author)

  10. Technology Transfer, Foreign Direct Investment and Economic ...

    African Journals Online (AJOL)

    The aim of this study is to investigate the long-run equilibrium relationship between various international factors and economic growth, as well as to assess the short-term impact of inward FDI, trade and economic growth on international technology transfer to Nigeria. To achieve this, the study used a time series data from ...

  11. Integrated light in direct excitation and energy transfer luminescence

    OpenAIRE

    Chimczak, Eugeniusz

    2007-01-01

    Integrated light in direct excitation and energy transfer luminescence has been investigated. In the investigations reported here, monomolecular centers were taken into account. It was found that the integrated light is equal to the product of generation rate and time of duration of excitation pulse for both direct excitation and energy transfer luminescence.

  12. Transcriptomic and genetic analysis of direct interspecies electron transfer

    DEFF Research Database (Denmark)

    Shrestha, Pravin Malla; Rotaru, Amelia-Elena; Summers, Zarath M

    2013-01-01

    The possibility that metatranscriptomic analysis could distinguish between direct interspecies electron transfer (DIET) and H2 interspecies transfer (HIT) in anaerobic communities was investigated by comparing gene transcript abundance in cocultures in which Geobacter sulfurreducens....... These results demonstrate that there are unique gene expression patterns that distinguish DIET from HIT and suggest that metatranscriptomics may be a promising route to investigate interspecies electron transfer pathways in more-complex environments....

  13. Technology Transfer, Foreign Direct Investment and International Trade

    OpenAIRE

    Leonard K. Cheng

    2000-01-01

    By developing a Ricardian trade model that features technology transfer via foreign direct investment (FDI), we show that technology transfer via multinational enterprises (MNEs) increases world output and trade in goods and services. When there are many goods a continuous reduction in the cost of technology transfer will cause increasingly more technologically advanced goods to go through the product cycle, i.e., goods initially produced in the advanced North are later produced in the backwa...

  14. 77 FR 46855 - Small Business Technology Transfer Program Policy Directive

    Science.gov (United States)

    2012-08-06

    ... SMALL BUSINESS ADMINISTRATION 13 CFR Chapter I RIN 3245-AF45 Small Business Technology Transfer Program Policy Directive AGENCY: Small Business Administration. ACTION: Final policy directive with request for comments. SUMMARY: The U.S. Small Business Administration (SBA) is amending its Small Business...

  15. Droplet heat transfer and chemical reactions during direct containment heating

    International Nuclear Information System (INIS)

    Baker, L. Jr.

    1986-01-01

    A simplified model of heat transfer and chemical reaction has been adapted to evaluate the expected behavior of droplets containing unreacted Zircaloy and stainless steel moving through the containment atmosphere during postulated accidents involving direct containment heating. The model includes internal and external diffusive resistances to reaction. The results indicate that reactions will be incomplete for many conditions characteristic of direct containment heating sequences

  16. Transfer Pricing Principles VAT/GST v. Direct Taxation

    DEFF Research Database (Denmark)

    Jensen, Dennis Ramsdahl

    2009-01-01

    Convention, [2] including an examination of whether it is appropriate to base transfer pricing rules on the same principles in the two different areas of tax law. [1] Council Directive 2006/112/EC of 28 November 2006 on the common system of value added tax, OJ L 347 of 11 December 2006, pp. 1-118 (EC VAT......In this paper the optional transfer pricing provisions in the EC VAT Directive [1] are subject to a more detailed analysis, with a view to considering them in the light of the well-known principles for transfer pricing in the area of income tax law, as set out in Art. 9 of the OECD Model Tax...... Directives are to be construed as references to the EC VAT Directive and should be read in accordance with the correlation table in Annex XII. [2] OECD Model Tax Convention on Income and on Capital (OECD Model Tax Convention)....

  17. Allergies, asthma, and pollen

    Science.gov (United States)

    Reactive airway - pollen; Bronchial asthma - pollen; Triggers - pollen; Allergic rhinitis - pollen ... Things that make allergies or asthma worse are called triggers. It is important to know your triggers because avoiding them is your first step toward feeling better. ...

  18. Direct contact between dendritic cells and bronchial epithelial cells inhibits T cell recall responses towards mite and pollen allergen extracts in vitro

    DEFF Research Database (Denmark)

    Papazian, Dick; Wagtmann, Valery R; Hansen, Soren

    2015-01-01

    (DCs), we have investigated recall T cell responses in allergic patients sensitized to house dust mite, grass, and birch pollen. Conclusions: Using allergen extract-loaded DCs to stimulate autologous allergen-specific T cell lines, we show that AEC-imprinted DCs inhibit T cell proliferation...... production of both Th1 and Th2 cytokines upon re-challenge. The inhibitory effects of AECs' contact with DCs were absent when allergen extract-loaded DCs had only been exposed to AECs supernatants, but present after direct contact with AECs. We conclude that direct contact between DCs and AECs inhibits T...

  19. Direct contact heat transfer characteristics between melting alloy and water

    International Nuclear Information System (INIS)

    Kinoshita, Izumi; Nishi, Yoshihisa; Furuya, Masahiro

    1995-01-01

    As a candidate for an innovative steam generator for fast breeder reactors, a heat exchanger with direct contact heat transfer between melting alloy and water was proposed. The evaluation of heat transfer characteristics of this heat exchanger is one of the research subjects for the design and development of the steam generator. In this study, the effect of the pressure on heat transfer characteristics and the required degree of superheating of melting alloy above water saturation temperature are evaluated during the direct contact heat transfer experiment by injecting water into Wood's alloy. In the experiment, the pressure, the temperature of the Wood's alloy, the flow rate of feed water, and the depth of the feed water injection point are varied as parameters. As a result of the experiment, the product of the degree of Wood's alloy superheating above water saturation temperature and the depth of the feed water injection point is constant for each pressure. This constant increases as the pressure rises. (author)

  20. Coconut (Cocos nucifera l.) pollen cryopreservation.

    Science.gov (United States)

    Karun, A; Sjini, K K; Niral, V; Amarnth, C H; Remya, P; Rajesh, M K; Samsudeen, K; Jerard, B A; Engelmann, F

    2014-01-01

    Coconut genetic resources are threatened by pests and pathogens, natural hazards and human activities. Cryopreservation is the only method allowing the safe and cost-effective long-term conservation of recalcitrant seed species such as coconut. The objective of this work was to test the effect of cryopreservation and of cryostorage duration on coconut pollen germination and fertility. Pollen of two coconut varieties (West Coast Tall WWCTW and Chowghat Orange Dwarf CODC) was collected in March-May over three successive years, desiccated to 7.5 % moisture content (FW) and cryopreserved by direct immersion in liquid nitrogen. Germination and pollen tube length (PTL) of desiccated and cryopreserved pollen were not significantly different for both WCT and COD over the three harvest months of the three consecutive years of study. Pollen germination ranged from 24 to 32 % in desiccated pollen whereas it was between 26 and 29 % in cryopreserved COD pollen. In the case of WCT, germination ranged from 30 to 31 % in desiccated pollen, while it was between 28 and 32 % in cryopreserved pollen. PTL of cryopreserved pollen ranged between 224-390 nm and 226-396 mm for COD and WCT, respectively. Germination of COD pollen varied between 29.0 and 44.1 % after 4 years and 1.0/1.5 years cryostorage, respectively. Germination of WCT pollen did not change significantly between 0 and 6 years cryostorage, being comprised between 32 (24 h) and 40 % (1.5 years). Germination and vigour of cryopreserved pollen were generally higher compared to that of pollen dried in oven and non-cryopreserved. Normal seed set was observed in COD and WCT palms using pollen cryostored for 6 months and 4 years. Cryopreserved pollen of five Tall and five Dwarf accessions displayed 24-31 % and 25-49 % germination, respectively. These results show that it is now possible to establish pollen cryobanks to contribute to coconut germplasm long-term conservation.

  1. The direction of bilateral transfer depends on the performance parameter.

    Science.gov (United States)

    Pan, Zhujun; van Gemmert, Arend W A

    2013-10-01

    To acquire a more comprehensive understanding of the learning benefits associated with bilateral transfer and to gain knowledge of possible mechanisms behind bilateral transfer, we investigated the transfer direction of several parameters which are assumed to represent important features of movement control in a visuo-motor task. During the study, participants learned a multidirectional point-to-point drawing task in which the visual feedback was rotated 45° and the gain was increased. Performance changes of the untrained hand in movement time, trajectory length, normalized jerk, initial direction error, ratio of the primary sub-movement time to the total movement time, and the accuracy of the aiming movement after the primary sub-movement were investigated as indices of learning from bilateral transfer. The results showed that performance parameters related to the initial production of the movement, such as the initial direction, ratio of primary sub-movement to the total movement time, and movement accuracy after the primary sub-movement, only transferred to the non-dominant, while hand performance variables related to the overall outcome, such as movement duration, movement smoothness, and trajectory length, transferred in both directions. The findings of the current study support the basic principle of the "dynamic dominance model" because it is suggested that overall improvements in the non-dominant system are controlled by trajectory parameters in visuo-motor tasks, which resulted in transference of the afore mentioned production parameters to rather occur to the non-dominant hand as opposed to transference to the dominant hand. Published by Elsevier B.V.

  2. Simple fabrication of active electrodes using direct laser transference

    International Nuclear Information System (INIS)

    Cavallo, P.; Coneo Rodriguez, R.; Broglia, M.; Acevedo, D.F.; Barbero, C.A.

    2014-01-01

    Highlights: •Electroactive materials can be transferred using a single pulse of laser light. •The transfer is made in air using a 6 ns pulse of Nd-YAG laser (532 or 1064 nm). •Conducting polymers films can be transferred maintaining the electroactivity. •Conducting polymer multilayers can be deposited using successive pulses. •Metallic (Au, Pt) transferred micro/nanoparticles are electrocatalytic. -- Abstract: Direct laser transference (DLT) method is applied to obtain electrodes modified with thin films of conducting polymers (CPs) or catalytic metals. A short (6–10 ns) pulse of laser light (second harmonic of Nd-YAG Laser, λ = 532 nm) is shined on the backside of a thin (<200 nm) film of the material to be transferred, which is deposited on a transparent substrate. The illuminated region heats up and the material (conducting polymer or metal) is thermally transferred to a solid target placed at short distance in air. In that ways, CPs are transferred onto polypropylene, glass, indium doped tin oxide (ITO), glassy carbon and gold films. In the same manner, electrocatalytic metals (platinum or gold) are transferred onto conductive substrates (glassy carbon or ITO films on glass). The films have been characterized by scanning electron microscopy, cyclic voltammetry, atomic force microscopy, UV-visible and Fourier Transform Infrared spectroscopies. The chemical, electrical and redox properties of the polymeric materials transferred remain unaltered after the transfer. Moreover, CP multilayers can be built applying DLT several times onto the same substrate. Besides polyaniline, it is shown that it is also possible to transfer functionalized polyanilines. The electrode modified with transferred Pt shows electrocatalytic activity toward methanol oxidation while ferricyanide shows a quasireversible behavior on electrodes modified with transferred Au. The method is simple and fast, works in air without complex environmental conditions and can produce active

  3. Controlling Water Intercalation Is Key to a Direct Graphene Transfer.

    Science.gov (United States)

    Verguts, Ken; Schouteden, Koen; Wu, Cheng-Han; Peters, Lisanne; Vrancken, Nandi; Wu, Xiangyu; Li, Zhe; Erkens, Maksiem; Porret, Clement; Huyghebaert, Cedric; Van Haesendonck, Chris; De Gendt, Stefan; Brems, Steven

    2017-10-25

    The key steps of a transfer of two-dimensional (2D) materials are the delamination of the as-grown material from a growth substrate and the lamination of the 2D material on a target substrate. In state-of-the-art transfer experiments, these steps remain very challenging, and transfer variations often result in unreliable 2D material properties. Here, it is demonstrated that interfacial water can insert between graphene and its growth substrate despite the hydrophobic behavior of graphene. It is understood that interfacial water is essential for an electrochemistry-based graphene delamination from a Pt surface. Additionally, the lamination of graphene to a target wafer is hindered by intercalation effects, which can even result in graphene delamination from the target wafer. For circumvention of these issues, a direct, support-free graphene transfer process is demonstrated, which relies on the formation of interfacial water between graphene and its growth surface, while avoiding water intercalation between graphene and the target wafer by using hydrophobic silane layers on the target wafer. The proposed direct graphene transfer also avoids polymer contamination (no temporary support layer) and eliminates the need for etching of the catalyst metal. Therefore, recycling of the growth template becomes feasible. The proposed transfer process might even open the door for the suggested atomic-scale interlocking-toy-brick-based stacking of different 2D materials, which will enable a more reliable fabrication of van der Waals heterostructure-based devices and applications.

  4. Computing algebraic transfer entropy and coupling directions via transcripts

    Science.gov (United States)

    Amigó, José M.; Monetti, Roberto; Graff, Beata; Graff, Grzegorz

    2016-11-01

    Most random processes studied in nonlinear time series analysis take values on sets endowed with a group structure, e.g., the real and rational numbers, and the integers. This fact allows to associate with each pair of group elements a third element, called their transcript, which is defined as the product of the second element in the pair times the first one. The transfer entropy of two such processes is called algebraic transfer entropy. It measures the information transferred between two coupled processes whose values belong to a group. In this paper, we show that, subject to one constraint, the algebraic transfer entropy matches the (in general, conditional) mutual information of certain transcripts with one variable less. This property has interesting practical applications, especially to the analysis of short time series. We also derive weak conditions for the 3-dimensional algebraic transfer entropy to yield the same coupling direction as the corresponding mutual information of transcripts. A related issue concerns the use of mutual information of transcripts to determine coupling directions in cases where the conditions just mentioned are not fulfilled. We checked the latter possibility in the lowest dimensional case with numerical simulations and cardiovascular data, and obtained positive results.

  5. Theory of nuclear heavy-ion direct transfer reactions

    International Nuclear Information System (INIS)

    Crowley, B.J.B.

    1979-01-01

    We review the distorted-wave approach to direct transfer reactions and draw attention to some of the shortcomings of current theories. We show that a reformulated form of the distorted-wave Born approximation (DWBA) for transfer can lead to important simplifications of the theory, which are valid for nuclear heavy-ion induced reactions at energies > or approx. =MeV/nucleon. In particular, in the semiclassical limit, it leads to a new and simple formula for the transfer t-matrix which includes all the essential physics while offering several important advantages over standard ''full-recoil finite-range'' DWBA. One such advantage is that the new formula is more transparent in that it is amendable to interpretation and analytical manipulation. At high-energy it is shown to reduce to one earlier deduced using eikonal-DWBA. The conditions for the validity of the new theory are discussed in detail. They are shown to be generally well satisfied for small-mass transfer between heavy-ions at energies at or above those particularly favour transfer (> or approx. =10 MeV/nucleon for transfer of valence nucleons). The restriction to small mass is not due to any recoil approximation; in fact, it is only a necessary restriction at certain energies. The theory treats recoil exactly. Consideration of the optimum dynamical conditions for transfer leads to a set of matching conditions. The presence of hitherto neglected absorption, arising from dynamical effects of poor matching, it suggested and qualitatively discussed. Condition under which such absorption may be neglected are derived. Results of numerical calculations are presented showing that the theory is capable of good agreement with standard full-recoil finite-range DWBA, and that it is capable of giving at least as good an account of experimental data for nucleon-transfer between heavy-ions at energies approx.10 MeV/nucleon

  6. Direct transfer of graphene films for polyurethane substrate

    Energy Technology Data Exchange (ETDEWEB)

    Vilani, C.; Romani, E.C.; Larrudé, D.G. [Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900 Rio de Janeiro, RJ (Brazil); Barbosa, Gelza M. [Diretoria de Sistemas de Armas da Marinha, Marinha do Brasil, 20010-00 Rio de Janeiro, RJ (Brazil); Freire, F.L., E-mail: lazaro@vdg.fis.puc-rio.br [Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900 Rio de Janeiro, RJ (Brazil); Centro Brasileiro de Pesquisas Físicas, 22290-180 Rio de Janeiro, RJ (Brazil)

    2015-11-30

    Highlights: • Graphene was prepared by CVD using copper foils as substrates. • Monolayer, bilayer and multilayer graphene were transferred to PU. • Samples were characterized by Raman and optical spectroscopies. • PU/monolayer graphene has transmittance around 80% in visible range. - Abstract: We have proposed the direct transfer of large-area graphene films grown by chemical vapor deposition to polymeric substrate by evaporating of solvents of polyurethane/tetrahydrofurane solution. The graphene films on polyurethane substrates were characterized by Raman spectroscopy, optical and atomic force microscopies and UV–vis spectroscopy measurements. The Raman spectra revealed that it is possible to transfer in a controlled manner monolayer, bilayer and multilayer graphene films over polyurethane substrate.

  7. Direct transfer of graphene films for polyurethane substrate

    International Nuclear Information System (INIS)

    Vilani, C.; Romani, E.C.; Larrudé, D.G.; Barbosa, Gelza M.; Freire, F.L.

    2015-01-01

    Highlights: • Graphene was prepared by CVD using copper foils as substrates. • Monolayer, bilayer and multilayer graphene were transferred to PU. • Samples were characterized by Raman and optical spectroscopies. • PU/monolayer graphene has transmittance around 80% in visible range. - Abstract: We have proposed the direct transfer of large-area graphene films grown by chemical vapor deposition to polymeric substrate by evaporating of solvents of polyurethane/tetrahydrofurane solution. The graphene films on polyurethane substrates were characterized by Raman spectroscopy, optical and atomic force microscopies and UV–vis spectroscopy measurements. The Raman spectra revealed that it is possible to transfer in a controlled manner monolayer, bilayer and multilayer graphene films over polyurethane substrate.

  8. Vacuum storage of yellow-poplar pollen

    Science.gov (United States)

    James R. Wilcox

    1966-01-01

    Vacuum-drying, followed by storage in vacuo or in an inert gas, is effective for storing pollen of many species. It permits storage at room environments without rigid controls of either temperature or humidity, an advantage that becomes paramount during long-distance transfers of pollen when critical storage conditions are impossible to maintain. In...

  9. Molecular cloning of plane pollen allergen Pla a 3 and its utility as diagnostic marker for peach associated plane pollen allergy.

    Science.gov (United States)

    Wangorsch, A; Larsson, H; Messmer, M; García-Moral, A; Lauer, I; Wolfheimer, S; Schülke, S; Bartra, J; Vieths, S; Lidholm, J; Scheurer, S

    2016-05-01

    Non-specific lipid transfer proteins (nsLTP) are considered to provoke allergic symptoms to plane tree pollen, which are frequently associated with peach allergy. The objective was to clone the cDNA of plane pollen nsLTP Pla a 3, to characterize IgE-binding and allergenic potency of recombinant Pla a 3 in comparison to its natural counterpart and peach nsLTP Pru p 3. Natural Pla a 3 was purified from plane pollen and analysed by mass spectrometry (MS). Recombinant Pla a 3 was characterized by SDS-PAGE and CD spectroscopy. Specific IgE to extract, components of plane pollen and Pru p 3 was measured by ImmunoCAP in sera of patients allergic to either plane pollen (n = 10), peach (n = 15) or both (n = 15). Biological potency of the proteins was investigated by in vitro mediator release assays and IgE cross-reactivity by competitive ELISA. Two Pla a 3 isoforms were identified. Recombinant Pla a 3 showed high purity, structural integrity, IgE-binding capacity comparable to nPla a 3 and biological potency. Sensitization to plane pollen extract was confirmed in 24/25 plane pollen allergics. The frequency of sensitization to Pla a 3 was 53% among patients allergic to both plane pollen and peach and 10% among plane pollen allergics tolerating peach where most patients were sensitized to Pla a 1. Pla a 3 and Pru p 3 showed strong bi-directional IgE cross-reactivity in patients allergic to peach and plane pollen, but not in peach allergics tolerating plane pollen. Levels of IgE-binding were generally higher to Pru p 3 than to Pla a 3. Sensitization to Pla a 3 is relevant in a subgroup of plane pollen allergics with concomitant peach allergy. IgE testing with Pla a 3 may serve as a marker to identify plane pollen allergic patients at risk of LTP-mediated food reactions and thereby improve in vitro diagnostic procedures. © 2016 John Wiley & Sons Ltd.

  10. Direct transfer of subwavelength plasmonic nanostructures on bioactive silk films.

    Science.gov (United States)

    Lin, Dianmin; Tao, Hu; Trevino, Jacob; Mondia, Jessica P; Kaplan, David L; Omenetto, Fiorenzo G; Dal Negro, Luca

    2012-11-27

    By a reusable transfer fabrication technique, we demonstrate high-fidelity fabrication of metal nanoparticles, optical nanoantennas, and nanohole arrays directly on a functional silk biopolymer. The ability to reproducibly pattern silk biopolymers with arbitrarily complex plasmonic arrays is of importance for a variety of applications in optical biosensing, tissue engineering, cell biology, and the development of novel bio-optoelectronic medical devices. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Spin-directed momentum transfers in SIDIS baryon production

    International Nuclear Information System (INIS)

    Sivers, D.

    2016-01-01

    The measurement of transverse single-spin asymmetries for baryon production in the target fragmentation region of semi-inclusive deep-inelastic scattering (SIDIS), can produce important insight into those nonperturbative aspects of QCD directly associated with confinement and with the dynamical breaking of chiral symmetry. We discuss here, in terms of spin-directed momentum transfers, the powerful quantum field- theoretical constraints on the spin-orbit dynamics underlying these transverse spin observables. The A τ -odd spin-directed momentum shifts, originating either in the target nucleon (δk TN ) or in the QCD jets (δp TN ) produced in the deep inelastic scattering process, represent significant quantum entanglement effects connecting information from current fragmentation with observables in target fragmentation. (author)

  12. Decision - making of Direct Customers Based on Available Transfer Capability

    Science.gov (United States)

    Quan, Tang; Zhaohang, Lin; Huaqiang, Li

    2017-05-01

    Large customer direct-power-purchasing is a hot spot in the electricity market reform. In this paper, the author established an Available Transfer Capability (ATC) model which takes uncertain factors into account, applied the model into large customer direct-power-purchasing transactions and improved the reliability of power supply during direct-power-purchasing by introducing insurance theory. The author also considered the customers loss suffered from power interruption when building ATC model, established large customer decision model, took purchasing quantity of power from different power plants and reserved capacity insurance as variables, targeted minimum power interruption loss as optimization goal and best solution by means of particle swarm algorithm to produce optimal power purchasing decision of large consumers. Simulation was made through IEEE57 system finally and proved that such method is effective.

  13. Seasonal variation in diurnal atmospheric grass pollen concentration profiles

    DEFF Research Database (Denmark)

    Peel, Robert George; Ørby, Pia Viuf; Skjøth, Carsten Ambelas

    2014-01-01

    the time of day when peak concentrations are most likely to occur using seasonally averaged diurnal profiles. Atmospheric pollen loads are highly dependent upon emissions, and different species of grass are known to flower and emit pollen at different times of the day and during different periods......In this study, the diurnal atmospheric grass pollen concentration profile within the Danish city of Aarhus was shown to change in a systematic manner as the pollen season progressed. Although diurnal grass pollen profiles can differ greatly from day-to-day, it is common practice to establish...... of the pollen season. Pollen concentrations are also influenced by meteorological factors - directly through those parameters that govern pollen dispersion and transport, and indirectly through the weather-driven flowering process. We found that three different profiles dominated the grass pollen season...

  14. Direct transfer and Raman characterization of twisted graphene bilayer

    International Nuclear Information System (INIS)

    Othmen, R.; Arezki, H.; Boutchich, M.; Ajlani, H.; Oueslati, M.; Cavanna, A.; Madouri, A.

    2015-01-01

    Twisted bilayer graphene (tBLG) is constituted of a two-graphene layer with a mismatch angle θ between the two hexagonal structures. It has recently attracted much attention—thanks to its diverse electronic and optical properties. Here, we study the tBLG fabricated by the direct transfer of graphene monolayer prepared by chemical vapor deposition (CVD) onto another CVD graphene layer remaining attached to the copper foil. We show that high quality and homogeneous tBLG can be obtained by the direct transfer which prevents interface contamination. In this situation, the top graphene layer plays a supporting mechanical role to the bottom graphene layer as confirmed by optical microscopy, scanning electron microscopy, and Raman spectroscopy measurements. The effect of annealing tBLG was also investigated using micro-Raman spectroscopy. The Raman spectra exhibit a splitting of the G peak as well as a change in the 2D band shape indicating a possible decoupling of the two monolayers. We attribute these changes to the different interactions of the top and bottom layers with the substrate

  15. Direct geoelectrical evidence of mass transfer at the laboratory scale

    Science.gov (United States)

    Swanson, Ryan D.; Singha, Kamini; Day-Lewis, Frederick D.; Binley, Andrew; Keating, Kristina; Haggerty, Roy

    2012-10-01

    Previous field-scale experimental data and numerical modeling suggest that the dual-domain mass transfer (DDMT) of electrolytic tracers has an observable geoelectrical signature. Here we present controlled laboratory experiments confirming the electrical signature of DDMT and demonstrate the use of time-lapse electrical measurements in conjunction with concentration measurements to estimate the parameters controlling DDMT, i.e., the mobile and immobile porosity and rate at which solute exchanges between mobile and immobile domains. We conducted column tracer tests on unconsolidated quartz sand and a material with a high secondary porosity: the zeolite clinoptilolite. During NaCl tracer tests we collected nearly colocated bulk direct-current electrical conductivity (σb) and fluid conductivity (σf) measurements. Our results for the zeolite show (1) extensive tailing and (2) a hysteretic relation between σf and σb, thus providing evidence of mass transfer not observed within the quartz sand. To identify best-fit parameters and evaluate parameter sensitivity, we performed over 2700 simulations of σf, varying the immobile and mobile domain and mass transfer rate. We emphasized the fit to late-time tailing by minimizing the Box-Cox power transformed root-mean square error between the observed and simulated σf. Low-field proton nuclear magnetic resonance (NMR) measurements provide an independent quantification of the volumes of the mobile and immobile domains. The best-fit parameters based on σf match the NMR measurements of the immobile and mobile domain porosities and provide the first direct electrical evidence for DDMT. Our results underscore the potential of using electrical measurements for DDMT parameter inference.

  16. Rabbit IgG directed to a synthetic C-terminal peptide of the major grass pollen allergen Lol p I inhibits human basophil histamine release induced by natural Lol p I

    NARCIS (Netherlands)

    van Ree, R.; Aalberse, R. C.

    1995-01-01

    The potential role of allergen-specific IgG antibodies as 'blocking' antibodies in allergen-induced human basophil histamine release was investigated. This was studied in a model with the major grass pollen allergen Lol p I and polyclonal rabbit antisera directed against this allergen and against a

  17. Directional radiometry and radiative transfer: A new paradigm

    International Nuclear Information System (INIS)

    Mishchenko, Michael I.

    2011-01-01

    Measurements with directional radiometers and calculations based on the radiative transfer equation (RTE) have been at the very heart of weather and climate modeling and terrestrial remote sensing. The quantification of the energy budget of the Earth's climate system requires exquisite measurements and computations of the incoming and outgoing electromagnetic energy, while global characterization of climate system's components relies heavily on theoretical inversions of observational data obtained with various passive and active instruments. The same basic problems involving electromagnetic energy transport and its use for diagnostic and characterization purposes are encountered in numerous other areas of science, biomedicine, and engineering. Yet both the discipline of directional radiometry and the radiative transfer theory (RTT) have traditionally been based on phenomenological concepts many of which turn out to be profound misconceptions. Contrary to the widespread belief, a collimated radiometer does not, in general, measure the flow of electromagnetic energy along its optical axis, while the specific intensity does not quantify the amount of electromagnetic energy transported in a given direction. The recently developed microphysical approach to radiative transfer and directional radiometry is explicitly based on the Maxwell equations and clarifies the physical nature of measurements with collimated radiometers and the actual content of the RTE. It reveals that the specific intensity has no fundamental physical meaning besides being a mathematical solution of the RTE, while the RTE itself is nothing more than an intermediate auxiliary equation. Only under special circumstances detailed in this review can the solution of the RTE be used to compute the time-averaged local Poynting vector as well as be measured by a collimated radiometer. These firmly established facts make the combination of the RTE and a collimated radiometer useful in a well-defined range of

  18. Facile direct electron transfer in glucose oxidase modified electrodes

    International Nuclear Information System (INIS)

    Wang Dan; Chen Liwei

    2009-01-01

    Glucose oxidase (GOx) is widely used in the glucose biosensor industry. However, mediatorless direct electron transfer (DET) from GOx to electrode surfaces is very slow. Recently, mediatorless DET has been reported via the incorporation of nanomaterials such as carbon nanotubes and nanoparticles in the modification of electrodes. Here we report GOx electrodes showing DET without the need for any nanomaterials. The enzyme after immobilization with poly-L-lysine (PLL) and Nafion retains the biocatalytic activities and oxidizes glucose efficiently. The amperometric response of Nafion-PLL-GOx modified electrode is linearly proportional to the concentration of glucose up to 10 mM with a sensitivity of 0.75 μA/mM at a low detection potential (-0.460 V vs. Ag/AgCl). The methodology developed in this study will have impact on glucose biosensors and biofuel cells and may potentially simplify enzyme immobilization in other biosensing systems.

  19. Direct observation of coherent energy transfer in nonlinear micromechanical oscillators.

    Science.gov (United States)

    Chen, Changyao; Zanette, Damián H; Czaplewski, David A; Shaw, Steven; López, Daniel

    2017-05-26

    Energy dissipation is an unavoidable phenomenon of physical systems that are directly coupled to an external environmental bath. In an oscillatory system, it leads to the decay of the oscillation amplitude. In situations where stable oscillations are required, the energy dissipated by the vibrations is usually compensated by replenishment from external energy sources. Consequently, if the external energy supply is removed, the amplitude of oscillations start to decay immediately, since there is no means to restitute the energy dissipated. Here, we demonstrate a novel dissipation engineering strategy that can support stable oscillations without supplying external energy to compensate losses. The fundamental intrinsic mechanism of resonant mode coupling is used to redistribute and store mechanical energy among vibrational modes and coherently transfer it back to the principal mode when the external excitation is off. To experimentally demonstrate this phenomenon, we exploit the nonlinear dynamic response of microelectromechanical oscillators to couple two different vibrational modes through an internal resonance.

  20. Experimental investigation of direct contact three phase boiling heat transfer

    International Nuclear Information System (INIS)

    Bruce, W.D.

    1981-01-01

    The system which was studied in the present work consisted of one liquid undergoing vaporization by contact with a hotter immiscible liquid. The liquids and vapor were contacted in a counterflow spray column with only differential increases in vapor quality. Experiments yielded vertical temperature profiles, flow rates of the phases, liquid holdups, pressure drops, and a characterization of flow patterns. A micro-computer was utilized for measuring temperatures in the column at the rate of 1500 to 1600 times per second at several depths. Analysis of the experimental data indicate that the maximum temperature difference between the phases is 0.5F 0 , and that a temperature crossover occurs at the lower end of the column. The heat transfer fluid undergoes flash vaporization at its inlet at the top of the column, and much of its sensible heat is tranferred to the dispersed phase near the top of the column. Temperature profiles along the length of the boiler are nearly flat, and very little heat transfer occurs in the lower part of the boiler. A chemical method was developed for measuring effective interfacial area in a direct contact boiler. The theoretical basis of the method is discussed, and physico-chemical data necessary for application of the technique are reported. Water solubility of methyl salicylate was measured as a function of temperature, and the second order reaction rate coefficient for saponification of methyl salicylate by sodium hydroxide was determined from sodium hydroxide concentration versus time data and a computer model of a well-mixed semibatch reactor. The activation energy for the reaction was found to be 9.58 kilocalories per gram mole

  1. Demonstration of Lignin-to-Peroxidase Direct Electron Transfer

    Science.gov (United States)

    Sáez-Jiménez, Verónica; Baratto, Maria Camilla; Pogni, Rebecca; Rencoret, Jorge; Gutiérrez, Ana; Santos, José Ignacio; Martínez, Angel T.; Ruiz-Dueñas, Francisco Javier

    2015-01-01

    Versatile peroxidase (VP) is a high redox-potential peroxidase of biotechnological interest that is able to oxidize phenolic and non-phenolic aromatics, Mn2+, and different dyes. The ability of VP from Pleurotus eryngii to oxidize water-soluble lignins (softwood and hardwood lignosulfonates) is demonstrated here by a combination of directed mutagenesis and spectroscopic techniques, among others. In addition, direct electron transfer between the peroxidase and the lignin macromolecule was kinetically characterized using stopped-flow spectrophotometry. VP variants were used to show that this reaction strongly depends on the presence of a solvent-exposed tryptophan residue (Trp-164). Moreover, the tryptophanyl radical detected by EPR spectroscopy of H2O2-activated VP (being absent from the W164S variant) was identified as catalytically active because it was reduced during lignosulfonate oxidation, resulting in the appearance of a lignin radical. The decrease of lignin fluorescence (excitation at 355 nm/emission at 400 nm) during VP treatment under steady-state conditions was accompanied by a decrease of the lignin (aromatic nuclei and side chains) signals in one-dimensional and two-dimensional NMR spectra, confirming the ligninolytic capabilities of the enzyme. Simultaneously, size-exclusion chromatography showed an increase of the molecular mass of the modified residual lignin, especially for the (low molecular mass) hardwood lignosulfonate, revealing that the oxidation products tend to recondense during the VP treatment. Finally, mutagenesis of selected residues neighboring Trp-164 resulted in improved apparent second-order rate constants for lignosulfonate reactions, revealing that changes in its protein environment (modifying the net negative charge and/or substrate accessibility/binding) can modulate the reactivity of the catalytic tryptophan. PMID:26240145

  2. Direct Numerical Simulation of heat transfer in a turbulent flume

    International Nuclear Information System (INIS)

    Bergant, R.; Tiselj, I.

    2001-01-01

    Direct Numerical Simulation (DNS) can be used for the description of turbulent heat transfer in the fluid at low Reynolds numbers. DNS means precise solving of Navier-Stoke's equations without any extra turbulent models. DNS should be able to describe all relevant length scales and time scales in observed turbulent flow. The largest length scale is actually dimension of system and the smallest length and time scale is equal to Kolmogorov scale. In the present work simulations of fully developed turbulent velocity and temperature fields were performed in a turbulent flume (open channel) with pseudo-spectral approach at Reynolds number 2670 (friction Reynolds number 171) and constant Prandtl number 5.4, considering the fluid temperature as a passive scalar. Two ideal thermal boundary conditions were taken into account on the heated wall. The first one was an ideal isothermal boundary condition and the second one an ideal isoflux boundary condition. We observed different parameters like mean temperature and velocity, fluctuations of temperature and velocity, and auto-correlation functions.(author)

  3. Pollen reference collection digitization

    NARCIS (Netherlands)

    Ercan, F.E.Z.; Donders, T.H.; Bijl, P.K.; Wagner, F.

    2016-01-01

    The extensive Utrecht University pollen reference collection holds thousands of pollen samples of many species and genera from all over the world and has been a basis for the widely-used North West European Pollen Flora. These samples are fixed on glass slides for microscopy use, but the aging

  4. Mode of foreign entry, technology transfer, and foreign direct investment policy

    OpenAIRE

    Mattoo, Aaditya; Olarreaga, Marcelo; Saggi, Kamal

    2001-01-01

    Foreign direct investment can take place through the direct entry of foreign firms or the acquisition of existing domestic firms. Mattoo, Olarreaga, and Saggi examine the preferences of a foreign firm and the host country government with respect to these two modes of foreign direct investment in the presence of costly technology transfer. The tradeoff between technology transfer and market...

  5. Pollen flow of wheat under natural conditions in the Huanghuai River Wheat Region, China

    Science.gov (United States)

    Sun, Ai-Qing; Zhang, Chun-Qing; Wu, Cheng-Lai; Gao, Qing-Rong

    2015-01-01

    abstract The transgenic pollen spread is the main pathway of transgenic plant gene flow. The maximum distance of pollen dispersal (horizontal), the spatial dynamics of pollen movement (vertical), and the patterns of pollen dispersal are important considerations in biosafety assessments of genetically modified crops. To evaluate wheat (Triticum aestivum) pollen dispersal, we measured the pollen suspension velocity and analyzed pollen dispersal patterns under natural conditions in the Huanghuai River wheat-growing region in 2009. The pollen suspension velocity was 0.3–0.4 m/s. The highest pollen densities were detected in the north, northwest, and south of the pollen source. Pollen was dispersed over distances greater than 245 m in the northwest and northeast directions. At the pollen source center, pollen density decreased with increasing vertical height. In the north of the pollen source, the pollen density from 65 m to 225 m showed a wave-mode decrease with increasing height. The horizontal transport of pollen over longer distances fitted polynomial equations. In the north, the pollen density was highest at 45 m from the pollen source, and decreased with increasing distance. In the northwest, the pollen density showed a double-peak trend. In the northeast, pollen density was highest from 45 m to 125 m from the source. Wind speeds greater than the pollen suspension velocity and the duration of continuous gusts were the main factors affecting pollen dispersal. This information will be useful for determining the spatial isolation distances for hybrid seed production and for the commercial production of transgenic wheat. PMID:25658025

  6. Influence of high range of mass transfer coefficient and convection heat transfer on direct contact membrane distillation performance

    KAUST Repository

    Lee, Jung Gil

    2017-11-03

    In order to improve water production of membrane distillation (MD), the development of high performance membrane having better mass transfer and enhancement of convection heat transfer in MD module have been continuously investigated. This paper presents the relationship between the heat and mass transfer resistance across the membrane and the performance improvement. Various ranges of mass transfer coefficient (MTC) from normal (0.3×10−6 to 2.1×10−6kg/m2sPa: currently available membranes) to high (>2.1×10−6kg/m2sPa: membranes under development) were simulated using an experimentally validated model at different ranges of convection heat transfer by varying the inlet flow rates and spacer enhancement factor. The effect of mass transfer and convection heat transfer on the MD performance parameters including temperature polarization coefficient (TPC), mean permeate flux, and specific energy consumption were investigated in a direct contact MD (DCMD) configuration. Results showed that improving the MTC at the low ranges is more important than that at the high ranges where the heat transfer resistance becomes dominant and hence the convection heat transfer coefficient must be increased. Therefore, an effort on designing MD modules using feed and permeate spacers and controlling the membrane surface roughness to increase the convection heat transfer and TPC in the channel aiming to enhance the flux is required because the currently developed mass transfer has almost reached the critical point.

  7. Monitoring, modelling and forecasting of the pollen season

    DEFF Research Database (Denmark)

    Scheifinger, Helfried; Belmonte, Jordina; Buters, Jeroen

    2013-01-01

    The section about monitoring covers the development of phenological networks, remote sensing of the season cycle of the vegetation, the emergence of the science of aerobiology and, more specifically, aeropalynology, pollen sampling instruments, pollen counting techniques, applications of aeropaly......The section about monitoring covers the development of phenological networks, remote sensing of the season cycle of the vegetation, the emergence of the science of aerobiology and, more specifically, aeropalynology, pollen sampling instruments, pollen counting techniques, applications...... of aeropalynology in agriculture and the European Pollen Information System. Three data sources are directly related with aeropalynology: phenological observations, pollen counts and remote sensing of the vegetation activity. The main future challenge is the assimilation of these data streams into numerical pollen...

  8. Syntrophic growth with direct interspecies electron transfer as the primary mechanism for energy exchange

    DEFF Research Database (Denmark)

    Shrestha, Pravin Malla; Rotaru, Amelia-Elena; Aklujkar, Muktak

    2013-01-01

    Direct interspecies electron transfer (DIET) through biological electrical connections is an alternative to interspecies H2 transfer as a mechanism for electron exchange in syntrophic cultures. However, it has not previously been determined whether electrons received via DIET yield energy...... dehydrogenase, the pilus-associated c-type cytochrome OmcS and pili consistent with electron transfer via DIET. These results suggest that electrons transferred via DIET can serve as the sole energy source to support anaerobic respiration....

  9. Direct observation of triplet energy transfer from semiconductor nanocrystals.

    Science.gov (United States)

    Mongin, Cédric; Garakyaraghi, Sofia; Razgoniaeva, Natalia; Zamkov, Mikhail; Castellano, Felix N

    2016-01-22

    Triplet excitons are pervasive in both organic and inorganic semiconductors but generally remain confined to the material in which they originate. We demonstrated by transient absorption spectroscopy that cadmium selenide semiconductor nanoparticles, selectively excited by green light, engage in interfacial Dexter-like triplet-triplet energy transfer with surface-anchored polyaromatic carboxylic acid acceptors, extending the excited-state lifetime by six orders of magnitude. Net triplet energy transfer also occurs from surface acceptors to freely diffusing molecular solutes, further extending the lifetime while sensitizing singlet oxygen in an aerated solution. The successful translation of triplet excitons from semiconductor nanoparticles to the bulk solution implies that such materials are generally effective surrogates for molecular triplets. The nanoparticles could thereby potentially sensitize a range of chemical transformations that are relevant for fields as diverse as optoelectronics, solar energy conversion, and photobiology. Copyright © 2016, American Association for the Advancement of Science.

  10. Research progresses and future directions on pool boiling heat transfer

    OpenAIRE

    M. Kumar; V. Bhutani; P. Khatak

    2015-01-01

    This paper reviews the previous work carried on pool boiling heat transfer during heating of various liquids and commodities categorized as refrigerants and dielectric fluids, pure liquids, nanofluids, hydrocarbons and additive mixtures, as well as natural and synthetic colloidal solutions. Nucleate pool boiling is an efficient and effective method of boiling because high heat fluxes are possible with moderate temperature differences. It is characterized by the growth of bubbles on a heated s...

  11. Consumptive emasculation: the ecological and evolutionary consequences of pollen theft.

    Science.gov (United States)

    Hargreaves, Anna L; Harder, Lawrence D; Johnson, Steven D

    2009-05-01

    Many of the diverse animals that consume floral rewards act as efficient pollinators; however, others 'steal' rewards without 'paying' for them by pollinating. In contrast to the extensive studies of the ecological and evolutionary consequences of nectar theft, pollen theft and its implications remain largely neglected, even though it affects plant reproduction more directly. Here we review existing studies of pollen theft and find that: (1) most pollen thieves pollinate other plant species, suggesting that theft generally arises from a mismatch between the flower and thief that precludes pollen deposition, (2) bees are the most commonly documented pollen thieves, and (3) the floral traits that typically facilitate pollen theft involve either spatial or temporal separation of sex function within flowers (herkogamy and dichogamy, respectively). Given that herkogamy and dichogamy occur commonly and that bees are globally the most important floral visitors, pollen theft is likely a greatly under-appreciated component of floral ecology and influence on floral evolution. We identify the mechanisms by which pollen theft can affect plant fitness, and review the evidence for theft-induced ecological effects, including pollen limitation. We then explore the consequences of pollen theft for the evolution of floral traits and sexual systems, and conclude by identifying key directions for future research.

  12. Bi-directional magnetic resonance based wireless power transfer for electronic devices

    International Nuclear Information System (INIS)

    Kar, Durga P.; Nayak, Praveen P.; Bhuyan, Satyanarayan; Mishra, Debasish

    2015-01-01

    In order to power or charge electronic devices wirelessly, a bi-directional wireless power transfer method has been proposed and experimentally investigated. In the proposed design, two receiving coils are used on both sides of a transmitting coil along its central axis to receive the power wirelessly from the generated magnetic fields through strongly coupled magnetic resonance. It has been observed experimentally that the maximum power transfer occurs at the operating resonant frequency for optimum electric load connected across the receiving coils on both side. The optimum wireless power transfer efficiency is 88% for the bi-directional power transfer technique compared 84% in the one side receiver system. By adopting the developed bi-directional power transfer method, two electronic devices can be powered up or charged simultaneously instead of a single device through usual one side receiver system without affecting the optimum power transfer efficiency

  13. Bi-directional magnetic resonance based wireless power transfer for electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Kar, Durga P.; Nayak, Praveen P.; Bhuyan, Satyanarayan; Mishra, Debasish [Department of Electronics and Instrumentation Engineering, Institute of Technical Education and Research, Siksha ‘O’ Anushandhan University, Bhubaneswar 751030 (India)

    2015-09-28

    In order to power or charge electronic devices wirelessly, a bi-directional wireless power transfer method has been proposed and experimentally investigated. In the proposed design, two receiving coils are used on both sides of a transmitting coil along its central axis to receive the power wirelessly from the generated magnetic fields through strongly coupled magnetic resonance. It has been observed experimentally that the maximum power transfer occurs at the operating resonant frequency for optimum electric load connected across the receiving coils on both side. The optimum wireless power transfer efficiency is 88% for the bi-directional power transfer technique compared 84% in the one side receiver system. By adopting the developed bi-directional power transfer method, two electronic devices can be powered up or charged simultaneously instead of a single device through usual one side receiver system without affecting the optimum power transfer efficiency.

  14. Direct Electron Transfer of Dehydrogenases for Development of 3rd Generation Biosensors and Enzymatic Fuel Cells

    Directory of Open Access Journals (Sweden)

    Paolo Bollella

    2018-04-01

    Full Text Available Dehydrogenase based bioelectrocatalysis has been increasingly exploited in recent years in order to develop new bioelectrochemical devices, such as biosensors and biofuel cells, with improved performances. In some cases, dehydrogeases are able to directly exchange electrons with an appropriately designed electrode surface, without the need for an added redox mediator, allowing bioelectrocatalysis based on a direct electron transfer process. In this review we briefly describe the electron transfer mechanism of dehydrogenase enzymes and some of the characteristics required for bioelectrocatalysis reactions via a direct electron transfer mechanism. Special attention is given to cellobiose dehydrogenase and fructose dehydrogenase, which showed efficient direct electron transfer reactions. An overview of the most recent biosensors and biofuel cells based on the two dehydrogenases will be presented. The various strategies to prepare modified electrodes in order to improve the electron transfer properties of the device will be carefully investigated and all analytical parameters will be presented, discussed and compared.

  15. Research progresses and future directions on pool boiling heat transfer

    Directory of Open Access Journals (Sweden)

    M. Kumar

    2015-12-01

    Full Text Available This paper reviews the previous work carried on pool boiling heat transfer during heating of various liquids and commodities categorized as refrigerants and dielectric fluids, pure liquids, nanofluids, hydrocarbons and additive mixtures, as well as natural and synthetic colloidal solutions. Nucleate pool boiling is an efficient and effective method of boiling because high heat fluxes are possible with moderate temperature differences. It is characterized by the growth of bubbles on a heated surface. It occurs during boiling of liquids for excess temperature ranging from 5 to 30 °C in various processes related to high vaporization of liquid for specific purposes like sugarcane juice heating for jaggery making, milk heating for khoa making, steam generation, cooling of electronic equipments, refrigeration and etcetera. In this review paper, pool boiling method during heating of liquids for specific purpose is depicted. It is inferred that enhancement in pool boiling heat transfer is a challenging and complex task. Also, recent research and use of various correlations for natural convection pool boiling is reviewed.

  16. Direct electron transfer from glucose oxidase immobilized on a nano-porous glassy carbon electrode

    International Nuclear Information System (INIS)

    Haghighi, Behzad; Tabrizi, Mahmoud Amouzadeh

    2011-01-01

    Highlights: → A direct electron transfer reaction of glucose oxidase was observed on the surface of a nano-porous glassy carbon electrode. → A pair of well-defined and reversible redox peaks was observed at the formal potential of approximately -0.439 V. → The apparent electron transfer rate constant was measured to be 5.27 s -1 . → A mechanism for the observed direct electron transfer reaction was proposed, which consists of a two-electron and a two-proton transfer. - Abstract: A pair of well-defined and reversible redox peaks was observed for the direct electron transfer (DET) reaction of an immobilized glucose oxidase (GOx) on the surface of a nano-porous glassy carbon electrode at the formal potential (E o ') of -0.439 V versus Ag/AgCl/saturated KCl. The electron transfer rate constant (k s ) was calculated to be 5.27 s -1 . The dependence of E o ' on pH indicated that the direct electron transfer of the GOx was a two-electron transfer process, coupled with two-proton transfer. The results clearly demonstrate that the nano-porous glassy carbon electrode is a cost-effective and ready-to-use scaffold for the fabrication of a glucose biosensor.

  17. Direct electron transfer from glucose oxidase immobilized on a nano-porous glassy carbon electrode

    Energy Technology Data Exchange (ETDEWEB)

    Haghighi, Behzad, E-mail: haghighi@iasbs.ac.ir [Department of Chemistry, Institute for Advanced Studies in Basic Sciences, P.O. Box 45195-1159, Gava Zang, Zanjan (Iran, Islamic Republic of); Tabrizi, Mahmoud Amouzadeh [Department of Chemistry, Institute for Advanced Studies in Basic Sciences, P.O. Box 45195-1159, Gava Zang, Zanjan (Iran, Islamic Republic of)

    2011-11-30

    Highlights: > A direct electron transfer reaction of glucose oxidase was observed on the surface of a nano-porous glassy carbon electrode. > A pair of well-defined and reversible redox peaks was observed at the formal potential of approximately -0.439 V. > The apparent electron transfer rate constant was measured to be 5.27 s{sup -1}. > A mechanism for the observed direct electron transfer reaction was proposed, which consists of a two-electron and a two-proton transfer. - Abstract: A pair of well-defined and reversible redox peaks was observed for the direct electron transfer (DET) reaction of an immobilized glucose oxidase (GOx) on the surface of a nano-porous glassy carbon electrode at the formal potential (E{sup o}') of -0.439 V versus Ag/AgCl/saturated KCl. The electron transfer rate constant (k{sub s}) was calculated to be 5.27 s{sup -1}. The dependence of E{sup o}' on pH indicated that the direct electron transfer of the GOx was a two-electron transfer process, coupled with two-proton transfer. The results clearly demonstrate that the nano-porous glassy carbon electrode is a cost-effective and ready-to-use scaffold for the fabrication of a glucose biosensor.

  18. Piezoelectric power converter with bi-directional power transfer

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a bi-directional piezoelectric power converter com¬ prising a piezoelectric transformer. The piezoelectric transformer comprises an input electrode electrically coupled to a primary section of the piezoelectric transformer and an output electrode electrically...... coupled to an output section of the piezoelectric transformer to provide a transformer output signal. A bi-directional switching circuit is coupled between the output electrode and a DC or AC output voltage of the power converter. Forward and reverse current conducting periods of the bi......, a reverse current is conducted through the bi-directional switching circuit from the DC or AC output voltage to the output electrode to discharge the DC or AC output voltage and return power to the primary section of the piezoelectric transformer....

  19. Storage of strawberry pollen

    Directory of Open Access Journals (Sweden)

    Rafet Aslantaş

    2013-12-01

    Full Text Available This study was carried out to determine storage ability of strawberry pollen at different temperatures for three different strawberry cultivars 'Aliso', 'Brio', and 'Cruz'. Strawberry pollen was stored at room temperature (22 ±2°C, +4°C, -4°C and -18°C in stabile humidity conditions. Strawberry poIlen was germinated using the hanging drop method in a 20% sucrose solution. Pollen germination rate increased because of low temperature storage. Pollen stored at room temperature and +4°C, -4°C, and -18°C was kept for 8 months, about one year, and 20 months, respectively. Pollen germination rates decreased as the length of storage period increased. The reaction of all cultivars tested on the duration and temperature of storage was similar.

  20. Investigating Pollen and Gene Flow of WYMV-Resistant Transgenic Wheat N12-1 Using a Dwarf Male-Sterile Line as the Pollen Receptor.

    Science.gov (United States)

    Dong, Shanshan; Liu, Yan; Yu, Cigang; Zhang, Zhenhua; Chen, Ming; Wang, Changyong

    2016-01-01

    Pollen-mediated gene flow (PMGF) is the main mode of transgene flow in flowering plants. The study of pollen and gene flow of transgenic wheat can help to establish the corresponding strategy for preventing transgene escape and contamination between compatible genotypes in wheat. To investigate the pollen dispersal and gene flow frequency in various directions and distances around the pollen source and detect the association between frequency of transgene flow and pollen density from transgenic wheat, a concentric circle design was adopted to conduct a field experiment using transgenic wheat with resistance to wheat yellow mosaic virus (WYMV) as the pollen donor and dwarf male-sterile wheat as the pollen receptor. The results showed that the pollen and gene flow of transgenic wheat varied significantly among the different compass sectors. A higher pollen density and gene flow frequency was observed in the downwind SW and W sectors, with average frequencies of transgene flow of 26.37 and 23.69% respectively. The pollen and gene flow of transgenic wheat declined dramatically with increasing distance from its source. Most of the pollen grains concentrated within 5 m and only a few pollen grains were detected beyond 30 m. The percentage of transgene flow was the highest where adjacent to the pollen source, with an average of 48.24% for all eight compass directions at 0 m distance. Transgene flow was reduced to 50% and 95% between 1.61 to 3.15 m, and 10.71 to 20.93 m, respectively. Our results suggest that climate conditions, especially wind direction, may significantly affect pollen dispersal and gene flow of wheat. The isolation-by-distance model is one of the most effective methods for achieving stringent transgene confinement in wheat. The frequency of transgene flow is directly correlated with the relative density of GM pollen grains in air currents, and pollen competition may be a major factor influencing transgene flow.

  1. Investigating Pollen and Gene Flow of WYMV-Resistant Transgenic Wheat N12-1 Using a Dwarf Male-Sterile Line as the Pollen Receptor.

    Directory of Open Access Journals (Sweden)

    Shanshan Dong

    Full Text Available Pollen-mediated gene flow (PMGF is the main mode of transgene flow in flowering plants. The study of pollen and gene flow of transgenic wheat can help to establish the corresponding strategy for preventing transgene escape and contamination between compatible genotypes in wheat. To investigate the pollen dispersal and gene flow frequency in various directions and distances around the pollen source and detect the association between frequency of transgene flow and pollen density from transgenic wheat, a concentric circle design was adopted to conduct a field experiment using transgenic wheat with resistance to wheat yellow mosaic virus (WYMV as the pollen donor and dwarf male-sterile wheat as the pollen receptor. The results showed that the pollen and gene flow of transgenic wheat varied significantly among the different compass sectors. A higher pollen density and gene flow frequency was observed in the downwind SW and W sectors, with average frequencies of transgene flow of 26.37 and 23.69% respectively. The pollen and gene flow of transgenic wheat declined dramatically with increasing distance from its source. Most of the pollen grains concentrated within 5 m and only a few pollen grains were detected beyond 30 m. The percentage of transgene flow was the highest where adjacent to the pollen source, with an average of 48.24% for all eight compass directions at 0 m distance. Transgene flow was reduced to 50% and 95% between 1.61 to 3.15 m, and 10.71 to 20.93 m, respectively. Our results suggest that climate conditions, especially wind direction, may significantly affect pollen dispersal and gene flow of wheat. The isolation-by-distance model is one of the most effective methods for achieving stringent transgene confinement in wheat. The frequency of transgene flow is directly correlated with the relative density of GM pollen grains in air currents, and pollen competition may be a major factor influencing transgene flow.

  2. 40 CFR 266.111 - Standards for direct transfer.

    Science.gov (United States)

    2010-07-01

    ... (CONTINUED) STANDARDS FOR THE MANAGEMENT OF SPECIFIC HAZARDOUS WASTES AND SPECIFIC TYPES OF HAZARDOUS WASTE MANAGEMENT FACILITIES Hazardous Waste Burned in Boilers and Industrial Furnaces § 266.111 Standards for... boilers and industrial furnaces subject to §§ 266.102 or 266.103 if hazardous waste is directly...

  3. Direct numerical simulation of particulate flow with heat transfer

    NARCIS (Netherlands)

    Tavassoli Estahbanati, H; Kriebitzsch, S.H.L.; Hoef, van der M.A.; Peters, E.A.J.F.; Kuipers, J.A.M.

    2013-01-01

    The Immersed Boundary (IB) method proposed by Uhlmann for Direct Numerical Simulation (DNS) of fluid flow through dense fluid-particle systems is extended to systems with interphase heat transport. A fixed Eulerian grid is employed to solve the momentum and energy equations by traditional

  4. A method for the direct generation of comprehensive numerical solar building transfer functions

    Energy Technology Data Exchange (ETDEWEB)

    Chen, T.Y. [The Hong Kong Polytechnic University (China). Dept. of Building Services Engineering

    2003-02-01

    This paper describes a method for the direct generation of comprehensive numerical room transfer functions with any derived parameters as output, such as operative temperature or thermal load. Complex conductive, convective and radiant heat transfer processes, or any derived thermal parameters in buildings can be explicitly and precisely described by a generalized thermal network. This allows the s-transfer and z-transfer functions to be directly generated, using semi-symbolic analysis techniques, Cayley's expansion of determinant and Heaviside's expansion theorem. A simple algorithm is developed for finding the roots of the denominator in the inverse transform of the s-transfer functions, which ensures that no single root is missing. The techniques have been applied to generating the transfer functions of a passive solar room with floor heating. The example calculation demonstrates the high efficiency of the computational method. (author)

  5. Pollen tube branching in the ovary of five species of Oenothera

    Directory of Open Access Journals (Sweden)

    Renata Śnieżko

    2014-01-01

    Full Text Available Flowers of Oenothera hookeri Torr. et Gray, Oe. brevistylis and Oe. lamarkiana de Vries were pollinated after anthesis by insects. Oe. biennis L., Oe. suaveolens Desf and sulfurea were selfpollinated in the buds. Pollen morphology was slightly different: Oe. hookeri have regular, triporated pollen, often germinating through two pores; in Oe. suaveolens many pollen grains had callose patches on the intine; in Oe. brevistylis tetraporated pollen were more often than in other species; in Oe. lamarckiana many pollen grains were empty; in Oe. biennis and Oe. suaveolens pollen grain size and viability varied. The pollen tube growth and fertilization were similar in 5 species and can be considered as typical for Oenothera. In the ovary pollen tubes branched and changed their growth direction. Near micropyle they formed short branches to the inner integument. In the nucellus the pollen tube became swollen.

  6. Cash social transfers, direct taxes, and income distribution in late socialism

    OpenAIRE

    Milanovic, Branko

    1993-01-01

    The author analyzes the impact of direct taxes and cash social transfers on income distribution in Bulgaria, Czechoslovakia, Hungary, Poland and Yugoslavia in the years before the collapse of communism. He contrasts the results for socialist and market economies. Cash social transfers accounted for about a fifth of gross income, a proportion comparable with that in developed welfare economies. Generally, cash transfers were unrelated to income in socialist countries, in marked contrast with m...

  7. Does Foreign Direct Investment Transfer Technology Across Borders? A Reexamination

    OpenAIRE

    Jürgen Bitzer; Monika Kerekes

    2005-01-01

    Reexamining foreign direct investment (FDI) as a potential channel for knowledge diffusion -- based on industry data from seventeen OECD countries during the period 1973-2000 -- we find that FDI-receiving countries benefit strongly from FDI-related knowledge spillovers. We do not find evidence for positive FDI-related technology sourcing effects. Instead, our results suggest that outward FDI might have negative effects on the output of the FDI-sending country.

  8. Direct numerical simulation of heat transfer to CO2 at supercritical pressure in a vertical tube

    International Nuclear Information System (INIS)

    Bae, Joong-Hun; Yoo, Jung-Yul; Choi, Hae-Cheon

    2003-01-01

    In the present study, the turbulent heat transfer to CO 2 at supercritical pressure in a vertical tube is investigated using Direct Numerical Simulation (DNS), where no turbulence model is adopted. Heat transfer to the supercritical pressure fluids is characterized by rapid variation of thermodynamic/ thermo-physical properties in the fluids. This change in properties occurs within a very narrow range of temperature across the so-called pseudo-critical temperature, causing a peculiar behavior of heat transfer characteristics. The buoyancy effects associated with very large changes in density proved to play a major role in turbulent heat transfer to supercritical pressure fluids. Depending on the degree of buoyancy effects, turbulent heat transfer may increase or significantly decrease, resulting in a local hot spot along the wall. Based on the results of the present DNS study combined with theoretical considerations for turbulent mixed convection heat transfer, the basic mechanism of this local heat transfer deterioration is explained

  9. Direct and indirect impact of federal transfer to individuals and to the government of Puerto Rico

    Directory of Open Access Journals (Sweden)

    Ángel Luis Ruiz Mercado

    2013-12-01

    Full Text Available The Puerto Rico Planning Board classifies individual transfer payments into two categories: “earned transfers” and “granted” transfers. The purpose of this work is to estimate the direct and indirect economic effects of federal and other transfer payments to Puerto Rico using two input-output models and two vectors of employment and income coefficients base on tables for years 1992 and 2002. The economic impacts were estimated for three economic indicators namely, gross output, direct and indirect employment and direct and indirect wage income. The results presented in this work shows that the argument that Puerto Ricans enjoy relatively generous income supplements and retirement benefits without imposing heavy tax burdens on highly compensated workers failed to distinguish that most of the transfer payments to individuals were in the category of earned transfers. It is doubtful that this type of transfer “imposeheavy tax burdens” to American taxpayers. Since we are an open economy mostof the income generated by transfer to individuals is spent of goods and servicesa substantial amount of which comes from United States. It is also doubtful thatearned transfer to individuals (especially transfers in the form of pensions andpayments to veterans have any significant impact on the labor force participation rate or the incentives to work.

  10. Directional Radiometry and Radiative Transfer: the Convoluted Path From Centuries-old Phenomenology to Physical Optics

    Science.gov (United States)

    Mishchenko, Michael I.

    2014-01-01

    This Essay traces the centuries-long history of the phenomenological disciplines of directional radiometry and radiative transfer in turbid media, discusses their fundamental weaknesses, and outlines the convoluted process of their conversion into legitimate branches of physical optics.

  11. Pollen-Mediated Movement of Herbicide Resistance Genes in Lolium rigidum.

    Directory of Open Access Journals (Sweden)

    Iñigo Loureiro

    Full Text Available The transfer of herbicide resistance genes by pollen is a major concern in cross-pollinated species such as annual ryegrass (Lolium rigidum. A two-year study was conducted in the greenhouse, under favorable conditions for pollination, to generate information on potential maximum cross-pollination. This maximum cross-pollination rate was 56.1%. A three-year field trial was also conducted to study the cross-pollination rates in terms of distance and orientation to an herbicide-resistant pollen source. Under field conditions, cross-pollination rates varied from 5.5% to 11.6% in plants adjacent to the pollen source and decreased with increasing distances (1.5 to 8.9% at 15 m distance and up to 4.1% at 25 m in the downwind direction. Environmental conditions influenced the cross-pollination both under greenhouse and field conditions. Data were fit to an exponential decay model to predict gene flow at increasing distances. This model predicted an average gene flow of 7.1% when the pollen donor and recipient plants were at 0 m distance from each other. Pollen-mediated gene flow declined by 50% at 16.7 m from the pollen source, yet under downwind conditions gene flow of 5.2% was predicted at 25 m, the farthest distance studied. Knowledge of cross-pollination rates will be useful for assessing the spread of herbicide resistance genes in L. rigidum and in developing appropriate strategies for its mitigation.

  12. How honey bees carry pollen

    Science.gov (United States)

    Matherne, Marguerite E.; Anyanwu, Gabriel; Leavey, Jennifer K.; Hu, David L.

    2017-11-01

    Honey bees are the tanker of the skies, carrying thirty percent of their weight in pollen per foraging trip using specialized orifices on their body. How do they manage to hang onto those pesky pollen grains? In this experimental study, we investigate the adhesion force of pollen to the honeybee. To affix pollen to themselves, honey bees form a suspension of pollen in nectar, creating a putty-like pollen basket that is skewered by leg hairs. We use tensile tests to show that the viscous force of the pollen basket is more than ten times the honeybee's flight force. This work may provide inspiration for the design of robotic flying pollinators.

  13. Feasibility study on applicability of direct contact heat transfer SGs or FBRs

    International Nuclear Information System (INIS)

    Kinoshita, Izumi; Nishi, Yoshihisa; Furuya, Masahiro

    1997-01-01

    As a candidate of an innovative steam generator for fast breeder reactors, heat exchanger with direct contact heat transfer between melting alloy and water was proposed. The objectives of this study are to obtain the technical feasibility of this concept, to evaluate the heat transfer characteristics of direct contact heat transfer and to estimate the size and volume of this SG. Followings are main results. (1) In the case of sodium tube failure, it is considered that steam and water will not enter into the primary sodium under appropriate countermeasures. (2) Under the condition of temperature and pressure of SG for FBRs, the phenomenon such as vapor explosion is not take place in this SG concept. (3) as a result of material compatibility test and analysis, it is considered that 9Cr-1Mo steel and 21/4cr-1Mo steel will be a candidate structural material. (4) It is considered that the production of oxides by the chemical reaction between melting alloy and water is mitigated by dissolving hydrogen gas in feed water. (5) The fundamental direct contact heat transfer characteristics between a melting alloy and water is obtained in following two regions. One is the evaporating region and the other is the superheating region. The effect of the system pressure on the heat transfer characteristics and the required degree of superheat of a melting alloy above the water saturation temperature are evaluated during direct contact heat transfer experiments by injecting water into a high temperature melting alloy. (6) Due to the high heat transfer performance of direct contact heat transfer, it is found that compact steam generation section will be expected. However, because of the characteristics of direct contact heat exchanger, achievement of high efficiency was difficult. In order to make a good use of this SG concept, improvement of efficiency is necessary. (author)

  14. Direct electron transfer: an approach for electrochemical biosensors with higher selectivity and sensitivity

    Directory of Open Access Journals (Sweden)

    Freire Renato S.

    2003-01-01

    Full Text Available The most promising approach for the development of electrochemical biosensors is to establish a direct electrical communication between the biomolecules and the electrode surface. This review focuses on advances, directions and strategies in the development of third generation electrochemical biosensors. Subjects covered include a brief description of the fundamentals of the electron transfer phenomenon and amperometric biosensor development (different types and new oriented enzyme immobilization techniques. Special attention is given to different redox enzymes and proteins capable of electrocatalyzing reactions via direct electron transfer. The analytical applications and future trends for third generation biosensors are also presented and discussed.

  15. Fencing direct memory access data transfers in a parallel active messaging interface of a parallel computer

    Science.gov (United States)

    Blocksome, Michael A.; Mamidala, Amith R.

    2013-09-03

    Fencing direct memory access (`DMA`) data transfers in a parallel active messaging interface (`PAMI`) of a parallel computer, the PAMI including data communications endpoints, each endpoint including specifications of a client, a context, and a task, the endpoints coupled for data communications through the PAMI and through DMA controllers operatively coupled to segments of shared random access memory through which the DMA controllers deliver data communications deterministically, including initiating execution through the PAMI of an ordered sequence of active DMA instructions for DMA data transfers between two endpoints, effecting deterministic DMA data transfers through a DMA controller and a segment of shared memory; and executing through the PAMI, with no FENCE accounting for DMA data transfers, an active FENCE instruction, the FENCE instruction completing execution only after completion of all DMA instructions initiated prior to execution of the FENCE instruction for DMA data transfers between the two endpoints.

  16. Direct comparison of graphene devices before and after transfer to different substrates

    International Nuclear Information System (INIS)

    Sachs, Raymond; Lin, Zhisheng; Odenthal, Patrick; Kawakami, Roland; Shi, Jing

    2014-01-01

    The entire graphene field-effect-transistor devices first fabricated on SiO 2 /Si are peeled from the surface and placed on a different wafer. Both longitudinal and transverse resistivity measurements of the devices before and after the transfer are measured to calculate the mobility for a direct comparison. After transferred to different SiO 2 /Si wafers, the mobility, generally, is comparable, and the defect density does not show any significant increase, which indicates the degradation due to the transfer process itself is minimal. The same method can be applied to transfer graphene devices to any arbitrary substrates (e.g., SrTiO 3 or STO). The transfer method developed here not only eliminates the need to locate single-layer graphene on non-SiO 2 /Si substrates for patterning but also provides a convenient way to study the effects of various substrates on graphene electronic properties

  17. Radioprotective effect of the pollen

    International Nuclear Information System (INIS)

    Jiang Ying; Zhu Gengbo; Huang Meiying; Yin Zhiwei; Fang Jixi; Fan Xiudi

    1990-10-01

    The radioprotective injury effect of pollen in animals was studied. Research came to the conclusion that: (1) the acute death rate of animals is decreased by the pollen; (2) the peripheral leukocytes and spleen-B-lymph cells of animals are increased by the pollen; (3) the activity of superoxide dimutase (SOD) in the erythrocytes of animals is increased by the pollen; (4) the pollen has the function of protecting the structure of the organs of thymus and testes and so on; (5) the plasma hydroxyproline of animals is remarkably decreased by the pollen

  18. Direct dry transfer of chemical vapor deposition graphene to polymeric substrates

    OpenAIRE

    Fechine, Guilhermino J. M.; Martin-Fernandez, Inigo; Yiapanis, George; de Oliveira, Ricardo V. Bof; Hu, Xiao; Yarovsky, Irene; Neto, Antonio H. Castro; Ozyilmaz, Barbaros

    2014-01-01

    We demonstrate the direct dry transfer of large area Chemical Vapor Deposition graphene to several polymers (low density polyethylene, high density polyethylene, polystyrene, polylactide acid and poly(vinylidenefluoride-co-trifluoroethylene) by means of only moderate heat and pressure, and the later mechanical peeling of the original graphene substrate. Simulations of the graphene-polymer interactions, rheological tests and graphene transfer at various experimental conditions show that contro...

  19. Directional radiometry and radiative transfer: The convoluted path from centuries-old phenomenology to physical optics

    International Nuclear Information System (INIS)

    Mishchenko, Michael I.

    2014-01-01

    This Essay traces the centuries-long history of the phenomenological disciplines of directional radiometry and radiative transfer in turbid media, discusses their fundamental weaknesses, and outlines the convoluted process of their conversion into legitimate branches of physical optics. - Highlights: • History of phenomenological radiometry and radiative transfer is described. • Fundamental weaknesses of these disciplines are discussed. • The process of their conversion into legitimate branches of physical optics is summarized

  20. Variations in pollen counts largely explained by climate and weather

    Science.gov (United States)

    Jung, Stephan; Damialis, Athanasios; Estrella, Nicole; Jochner, Susanne; Menzel, Annette

    2017-04-01

    The interaction between climate and vegetation is well studied within phenology. Climatic / weather conditions affect e.g. flowering date, length of vegetation period, start and end of the season and the plant growth. Besides phenological stages also pollen counts can be used to investigate the interaction between climate and vegetation. Pollen emission and distribution is directly influenced by temperature, wind speed, wind direction and humidity/precipitation. The objective of this project is to study daily/sub daily variations in pollen counts of woody and herbaceous plant species along an altitudinal gradient with different climatic conditions during the vegetation period. Measurements of pollen were carried out with three volumetric pollen traps installed at the altitudes 450 m a.s.l (Freising), 700 m a.s.l (Garmisch-Partenkirchen), and 2700 m a.s.l (Schneefernerhaus near Zugspitze) representing gradient from north of Munich towards the highest mountain of Germany. Airborne pollen concentrations were recorded during the years 2014-2015. The altitudinal range of these three stations accompanied by different microclimates ("space for time approach") can be used as proxy for climate change and to assess its impact on pollen counts and thus allergenic risk for human health. For example the pollen season is shortened and pollen amount is reduced at higher sites. For detailed investigations pollen of the species Plantago, Quercus, Poaceae, Cupressaceae, Cyperacea, Betula and Platanus were chosen, because those are found in appropriate quantities. In general, pollen captured in the pollen traps to a certain extent has its origin from the immediate surrounding. Thus, it mirrors local species distribution. But furthermore the distance of pollen transport is also based on (micro-) climatic conditions, land cover and topography. The pollen trap shortly below the summit of Zugspitze (Schneefernerhaus) has an alpine environment without vegetation nearby. Therefore, this

  1. Spatial variability in airborne pollen concentrations.

    Science.gov (United States)

    Raynor, G S; Ogden, E C; Hayes, J V

    1975-03-01

    Tests were conducted to determine the relationship between airborne pollen concentrations and distance. Simultaneous samples were taken in 171 tests with sets of eight rotoslide samplers spaced from one to 486 M. apart in straight lines. Use of all possible pairs gave 28 separation distances. Tests were conducted over a 2-year period in urban and rural locations distant from major pollen sources during both tree and ragweed pollen seasons. Samples were taken at a height of 1.5 M. during 5-to 20-minute periods. Tests were grouped by pollen type, location, year, and direction of the wind relative to the line. Data were analyzed to evaluate variability without regard to sampler spacing and variability as a function of separation distance. The mean, standard deviation, coefficient of variation, ratio of maximum to the mean, and ratio of minimum to the mean were calculated for each test, each group of tests, and all cases. The average coefficient of variation is 0.21, the maximum over the mean, 1.39 and the minimum over the mean, 0.69. No relationship was found with experimental conditions. Samples taken at the minimum separation distance had a mean difference of 18 per cent. Differences between pairs of samples increased with distance in 10 of 13 groups. These results suggest that airborne pollens are not always well mixed in the lower atmosphere and that a sample becomes less representative with increasing distance from the sampling location.

  2. Direct transfer of multilayer graphene grown on a rough metal surface using PDMS adhesion engineering

    Science.gov (United States)

    Jang, Heejun; Kang, Il-Suk; Lee, Youngbok; Cha, Yun Jeong; Yoon, Dong Ki; Ahn, Chi Won; Lee, Wonhee

    2016-09-01

    The direct transfer of graphene using polydimethylsiloxane (PDMS) stamping has advantages such as a ‘pick-and-place’ capability and no chemical residue problems. However, it is not easy to apply direct PDMS stamping to graphene grown via chemical vapor deposition on rough, grainy metal surfaces due to poor contact between the PDMS and graphene. In this study, graphene consisting of a mixture of monolayers and multiple layers grown on a rough Ni surface was directly transferred without the use of an adhesive layer. Liquid PDMS was cured on graphene to effect a conformal contact with the graphene. A fast release of graphene from substrate was achieved by carrying out wet-etching-assisted mechanical peeling. We also carried out a thermal post-curing of PDMS to control the level of adhesion between PDMS and graphene and hence facilitate a damage-free release of the graphene. Characterization of the transferred graphene by micro-Raman spectroscopy, SEM/EDS and optical microscopy showed neither cracks nor contamination from the transfer. This technique allows a fast and simple transfer of graphene, even for multilayer graphene grown on a rough surface.

  3. Directional resolution of head-related transfer functions required in binaural synthesis

    DEFF Research Database (Denmark)

    Minnaar, Pauli; Plogsties, Jan; Christensen, Flemming

    2005-01-01

    In binaural synthesis a virtual sound source is implemented by convolving an anechoic signal with a pair of head-related transfer functions (HRTFs). In order to represent all possible directions of the sound source with respect to the listener a discrete number of HRTFs are measured and interpola......In binaural synthesis a virtual sound source is implemented by convolving an anechoic signal with a pair of head-related transfer functions (HRTFs). In order to represent all possible directions of the sound source with respect to the listener a discrete number of HRTFs are measured...... and moving sound sources. A criterion was found that predicts the experimental results. This criterion was used to estimate the directional resolution required in binaural synthesis for all directions on the sphere around the head....

  4. Visualization of direct contact heat transfer between water and molten alloy by neutron radiography. 1

    International Nuclear Information System (INIS)

    Nishi, Yoshihisa; Furuya, Masahiro; Kinoshita, Izumi; Takenaka, Nobuyuki; Matsubayashi, Masahito.

    1997-01-01

    Design of an innovative Steam Generator (SG) for Liquid Metal Fast Reactors (LMFRs) using liquid-liquid direct contact heat transfer has been developing. In this concept, the SG shell is filled with a molten alloy, which is heated by primary sodium. Water is fed into the high-temperature, molten alloy, and evaporates by direct contact heating. In order to obtain the fundamental information needed to discuss the heat transfer mechanisms of direct contact between the water and molten alloy, this phenomenon was observed by neutron radiography. JRR-3M thermal neutron radiography at the Japan Atomic Energy Research Institute was used. This paper deals with the results of visualization of direct contact heat exchange in the molten alloy. (author)

  5. Germination and storage of pollen

    NARCIS (Netherlands)

    Visser, T.

    1955-01-01

    Germination of pear pollen markedly improved when boric acid was added to the medium. The pollen was more sensitive to boron in water than in 10 % sugar solution. Supplying weak solutions of boron to pear branches before flowering resulted in a good germination of the pollen in sugar solution

  6. Hybridizing pines with diluted pollen

    Science.gov (United States)

    Robert Z. Callaham

    1967-01-01

    Diluted pollens would have many uses by the tree breeder. Dilutions would be particularly advantageous in making many controlled pollinations with a limited amount of pollen. They also would be useful in artificial mass pollinations of orchards or single trees. Diluted pollens might help overcome troublesome genetic barriers to crossing. Feasibility o,f using diluted...

  7. Analysis and hazard evaluation of heat-transfer fluids for the direct contact cooling system

    International Nuclear Information System (INIS)

    Hong, Joo Hi; Lee, Yeon Hee; Shin, You Hwan; Karng, Sarng Woo; Kim, Seo Young; Kim, Young Gil

    2006-01-01

    This paper discusses several low-temperature heat-transfer fluids, including water-based inorganic salt, organic salt, alcohol/glycol mixtures, silicones, and halogenated hydrocarbons in order to choose the best heat-transfer fluid for the newly designed direct contact refrigeration system. So, it contains a survey on commercial products such as propylene glycol and potassium formate as newly used in super market and food processing refrigeration. The stability of commercial fluids at the working temperature of -20 .deg. C was monitored as a function of time up to two months. And organic and inorganic compositions of candidate fluids were obtained by analytical instruments such as ES, XRF, AAS, ICP-AES, GC, and GC-MS. Analysis results indicate that commercial propylene glycol is very efficient and safe heat transfer fluids for the direct cooling system with liquid phase

  8. Direct numerical simulations of flow and heat transfer over a circular cylinder at Re = 2000

    NARCIS (Netherlands)

    Vidya, Mahening Citra; Beishuizen, N.A.; van der Meer, Theodorus H.

    2016-01-01

    Unsteady direct numerical simulations of the flow around a circular cylinder have been performed at Re = 2000. Both two-dimensional and three-dimensional simulations were validated with laminar cold flow simulations and experiments. Heat transfer simulations were carried out and the time-averaged

  9. Cotton transformation via pollen tube pathway.

    Science.gov (United States)

    Wang, Min; Zhang, Baohong; Wang, Qinglian

    2013-01-01

    Although many gene transfer methods have been employed for successfully obtaining transgenic cotton, the major constraint in cotton improvement is the limitation of genotype because the majority of transgenic methods require plant regeneration from a single transformed cell which is limited by cotton tissue culture. Comparing with other plant species, it is difficult to induce plant regeneration from cotton; currently, only a limited number of cotton cultivars can be cultured for obtaining regenerated plants. Thus, development of a simple and genotype-independent genetic transformation method is particularly important for cotton community. In this chapter, we present a simple, cost-efficient, and genotype-independent cotton transformation method-pollen tube pathway-mediated transformation. This method uses pollen tube pathway to deliver transgene into cotton embryo sacs and then insert foreign genes into cotton genome. There are three major steps for pollen tube pathway-mediated genetic transformation, which include injection of -foreign genes into pollen tube, integration of foreign genes into plant genome, and selection of transgenic plants.

  10. Direct evidence of strain transfer for InAs island growth on compliant Si substrates

    Energy Technology Data Exchange (ETDEWEB)

    Marçal, L. A. B.; Magalhães-Paniago, R.; Malachias, Angelo, E-mail: angeloms@fisica.ufmg.br [Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, CEP 31270-901, Belo Horizonte (Brazil); Richard, M.-I. [European Synchrotron (ESRF), ID01 beamline, CS 40220, 38043 Grenoble Cedex 9 (France); Aix-Marseille University, IM2NP-CNRS, Faculté des Sciences de St Jérôme, 13397 Marseille (France); Cavallo, F. [Center for High Technology Materials, University of New Mexico, 1313 Goddard St., Albuquerque, New Mexico 87106 (United States); University of Wisconsin-Madison, 1500 Engineering Drive, Madison, Wisconsin 53706 (United States); Lagally, M. G. [University of Wisconsin-Madison, 1500 Engineering Drive, Madison, Wisconsin 53706 (United States); Schmidt, O. G. [Institute for Integrative Nanosciences, IFW-Dresden, D-01171 Dresden (Germany); Schülli, T. Ü. [European Synchrotron (ESRF), ID01 beamline, CS 40220, 38043 Grenoble Cedex 9 (France); Deneke, Ch. [Laboratório Nacional de Nanotecnologia (LNNano/CNPEM), C.P. 6192, CEP 13083-970, Campinas (Brazil)

    2015-04-13

    Semiconductor heteroepitaxy on top of thin compliant layers has been explored as a path to make inorganic electronics mechanically flexible as well as to integrate materials that cannot be grown directly on rigid substrates. Here, we show direct evidences of strain transfer for InAs islands on freestanding Si thin films (7 nm). Synchrotron X-ray diffraction measurements using a beam size of 300 × 700 nm{sup 2} can directly probe the strain status of the compliant substrate underneath deposited islands. Using a recently developed diffraction mapping technique, three-dimensional reciprocal space maps were reconstructed around the Si (004) peak for specific illuminated positions of the sample. The strain retrieved was analyzed using continuous elasticity theory via Finite-element simulations. The comparison of experiment and simulations yields the amount of strain from the InAs islands, which is transferred to the compliant Si thin film.

  11. Quantification of the activity of biomolecules in microarrays obtained by direct laser transfer.

    Science.gov (United States)

    Dinca, V; Ranella, A; Farsari, M; Kafetzopoulos, D; Dinescu, M; Popescu, A; Fotakis, C

    2008-10-01

    The direct-writing technique laser-induced forward transfer has been employed for the micro-array printing of liquid solutions of the enzyme horseradish peroxidase and the protein Titin on nitrocellulose solid surfaces. The effect of two UV laser pulse lengths, femtosecond and nanosecond has been studied in relation with maintaining the activity of the transferred biomolecules. The quantification of the active biomolecules after transfer has been carried out using Bradford assay, quantitative colorimetric enzymatic assay and fluorescence techniques. Spectrophotometric measurements of the HRP and the Titin activity as well as chromatogenic and fluorescence assay studies have revealed a connection between the properties of the deposited, biologically active biomolecules, the experimental conditions and the target composition. The bioassays have shown that up to 78% of the biomolecules remained active after femtosecond laser transfer, while this value reduced to 54% after nanosecond laser transfer. The addition of glycerol in a percentage up to 70% in the solution to be transferred has contributed to the stabilization of the micro-array patterns and the increase of their resolution.

  12. Directing the path of light-induced electron transfer at a molecular fork using vibrational excitation

    Science.gov (United States)

    Delor, Milan; Archer, Stuart A.; Keane, Theo; Meijer, Anthony J. H. M.; Sazanovich, Igor V.; Greetham, Gregory M.; Towrie, Michael; Weinstein, Julia A.

    2017-11-01

    Ultrafast electron transfer in condensed-phase molecular systems is often strongly coupled to intramolecular vibrations that can promote, suppress and direct electronic processes. Recent experiments exploring this phenomenon proved that light-induced electron transfer can be strongly modulated by vibrational excitation, suggesting a new avenue for active control over molecular function. Here, we achieve the first example of such explicit vibrational control through judicious design of a Pt(II)-acetylide charge-transfer donor-bridge-acceptor-bridge-donor 'fork' system: asymmetric 13C isotopic labelling of one of the two -C≡C- bridges makes the two parallel and otherwise identical donor→acceptor electron-transfer pathways structurally distinct, enabling independent vibrational perturbation of either. Applying an ultrafast UVpump(excitation)-IRpump(perturbation)-IRprobe(monitoring) pulse sequence, we show that the pathway that is vibrationally perturbed during UV-induced electron transfer is dramatically slowed down compared to its unperturbed counterpart. One can thus choose the dominant electron transfer pathway. The findings deliver a new opportunity for precise perturbative control of electronic energy propagation in molecular devices.

  13. Direct numerical simulations of fluid flow, heat transfer and phase changes

    Science.gov (United States)

    Juric, D.; Tryggvason, G.; Han, J.

    1997-01-01

    Direct numerical simulations of fluid flow, heat transfer, and phase changes are presented. The simulations are made possible by a recently developed finite difference/front tracking method based on the one-field formulation of the governing equations where a single set of conservation equations is written for all the phases involved. The conservation equations are solved on a fixed rectangular grid, but the phase boundaries are kept sharp by tracking them explicitly by a moving grid of lower dimension. The method is discussed and applications to boiling heat transfer and the solidification of drops colliding with a wall are shown.

  14. Atmospheric conditions during high ragweed pollen concentrations in Zagreb, Croatia

    Science.gov (United States)

    Prtenjak, Maja Telišman; Srnec, Lidija; Peternel, Renata; Madžarević, Valentina; Hrga, Ivana; Stjepanović, Barbara

    2012-11-01

    We examined the atmospheric conditions favourable to the occurrence of maximum concentrations of ragweed pollen with an extremely high risk of producing allergy. Over the 2002-2009 period, daily pollen data collected in Zagreb were used to identify two periods of high pollen concentration (> 600 grains/m3) for our analysis: period A (3-4 September 2002) and period B (6-7 September 2003). Synoptic conditions in both periods were very similar: Croatia was under the influence of a lower sector high pressure system moving slowly eastward over Eastern Europe. During the 2002-2009 period, this type of weather pattern (on ~ 70% of days), in conjunction with almost non-gradient surface pressure conditions in the area (on ~ 30% of days) characterised days when the daily pollen concentrations were higher than 400 grains/m3. Numerical experiments using a mesoscale model at fine resolution showed successful multi-day simulations reproducing the local topographic influence on wind flow and in reasonable agreement with available observations. According to the model, the relatively weak synoptic flow (predominantly from the eastern direction) allowed local thermal circulations to develop over Zagreb during both high pollen episodes. Two-hour pollen concentrations and 48-h back-trajectories indicated that regional-range transport of pollen grains from the central Pannonian Plain was the cause of the high pollen concentrations during period A. During period B, the north-westward regional-range transport in Zagreb was supplemented significantly by pronounced horizontal recirculation of pollen grains. This recirculation happened within the diurnal local circulation over the city, causing a late-evening increase in pollen concentration.

  15. Heat transfer modelling of two-phase bubbles swarm condensing in three - phase direct - contact condenser

    Directory of Open Access Journals (Sweden)

    Mahood Hameed B.

    2016-01-01

    Full Text Available An analytical model for the convective heat transfer coefficient and the two-phase bubble size of a three-phase direct contact heat exchanger was developed. Until the present, there has only been a theoretical model available that deals with a single two-phase bubble and a bubble train condensation in an immiscible liquid. However, to understand the actual heat transfer process within the three-phase direct contact condenser, characteristic models are required. A quasi - steady energy equation in a spherical coordinate system with a potential flow assumption and a cell model configuration has been simplified and solved analytically. The convective heat transfer in terms of Nu number has been derived, and it was found to be a function to Pe number and a system void fraction. In addition, the two-phase bubble size relates to the system void fraction and has been developed by solving a simple energy balance equation and using the derived convective heat transfer coefficient expression. Furthermore, the model correlates well with previous experimental data and theoretical results.

  16. Enhanced heat transfer with corrugated flow channel in anode side of direct methanol fuel cells

    International Nuclear Information System (INIS)

    Heidary, H.; Abbassi, A.; Kermani, M.J.

    2013-01-01

    Highlights: • Effect of corrugated flow channel on the heat exchange of DMFC is studied. • Corrugated boundary (except rectangular type) increase heat transfer up to 90%. • Average heat transfer in rectangular-corrugated boundary is less than straight one. • In Re > 60, wavy shape boundary has highest heat transfer. • In Re < 60, triangular shape boundary has highest heat transfer. - Abstract: In this paper, heat transfer and flow field analysis in anode side of direct methanol fuel cells (DMFCs) is numerically studied. To enhance the heat exchange between bottom cold wall and core flow, bottom wall of fluid delivery channel is considered as corrugated boundary instead of straight (flat) one. Four different shapes of corrugated boundary are recommended here: rectangular shape, trapezoidal shape, triangular shape and wavy (sinusoidal) shape. The top wall of the channel (catalyst layer boundary) is taken as hot boundary, because reaction occurs in catalyst layer and the bottom wall of the channel is considered as cold boundary due to coolant existence. The governing equations are numerically solved in the domain by the control volume approach based on the SIMPLE technique (1972). A wide spectrum of numerical studies is performed over a range of various shape boundaries, Reynolds number, triangle block number, and the triangle block amplitude. The performed parametric studies show that corrugated channel with trapezoidal, triangular and wavy shape enhances the heat exchange up to 90%. With these boundaries, cooling purpose of reacting flow in anode side of DMFCs would be better than straight one. Also, from the analogy between the heat and mass transfer problems, it is expected that the consumption of reacting species within the catalyst layer of DMFCs enhance. The present work provides helpful guidelines to the bipolar plate manufacturers of DMFCs to considerably enhance heat transfer and performance of the anode side of DMFC

  17. Direct metal transfer printing on flexible substrate for fabricating optics functional devices

    Science.gov (United States)

    Jiang, Yingjie; Zhou, Xiaohong; Zhang, Feng; Shi, Zhenwu; Chen, Linsen; Peng, Changsi

    2015-11-01

    New functional materials and devices based on metal patterns can be widely used in many new and expanding industries,such as flat panel displays, alternative energy,sensors and so on. In this paper, we introduce a new transfer printing method for fabricating metal optics functional devices. This method can directly transfer a metal pattern from a polyethylene terephthalate (PET)supported UV or polydimethylsiloxane (PDMS) pattern to another PET substrate. Purely taking advantage of the anaerobic UV curing adhesive (a-UV) on PET substrate, metal film can be easily peeled off from micro/nano-structured surface. As a result, metal film on the protrusion can be selectively transferred onto the target substrate, to make it the metal functional surface. But which on the bottom can not be transferred. This method provides low cost fabrication of metal thin film devices by avoiding high cost lithography process. Compared with conventional approach, this method can get more smooth rough edges and has wider tolerance range for the original master mold. Future developments and potential applications of this metal transfer method will be addressed.

  18. Direct determination of resonance energy transfer in photolyase: structural alignment for the functional state.

    Science.gov (United States)

    Tan, Chuang; Guo, Lijun; Ai, Yuejie; Li, Jiang; Wang, Lijuan; Sancar, Aziz; Luo, Yi; Zhong, Dongping

    2014-11-13

    Photoantenna is essential to energy transduction in photoinduced biological machinery. A photoenzyme, photolyase, has a light-harvesting pigment of methenyltetrahydrofolate (MTHF) that transfers its excitation energy to the catalytic flavin cofactor FADH¯ to enhance DNA-repair efficiency. Here we report our systematic characterization and direct determination of the ultrafast dynamics of resonance energy transfer from excited MTHF to three flavin redox states in E. coli photolyase by capturing the intermediates formed through the energy transfer and thus excluding the electron-transfer quenching pathway. We observed 170 ps for excitation energy transferring to the fully reduced hydroquinone FADH¯, 20 ps to the fully oxidized FAD, and 18 ps to the neutral semiquinone FADH(•), and the corresponding orientation factors (κ(2)) were determined to be 2.84, 1.53 and 1.26, respectively, perfectly matching with our calculated theoretical values. Thus, under physiological conditions and over the course of evolution, photolyase has adopted the optimized orientation of its photopigment to efficiently convert solar energy for repair of damaged DNA.

  19. Metagenomic insight into methanogenic reactors promoting direct interspecies electron transfer via granular activated carbon.

    Science.gov (United States)

    Park, Jeong-Hoon; Park, Jong-Hun; Je Seong, Hoon; Sul, Woo Jun; Jin, Kang-Hyun; Park, Hee-Deung

    2018-07-01

    To provide insight into direct interspecies electron transfer via granular activated carbon (GAC), the effect of GAC supplementation on anaerobic digestion was evaluated. Compared to control samples, the GAC supplementation increased the total amount of methane production and its production rate by 31% and 72%, respectively. 16S rDNA sequencing analysis revealed a shift in the archaeal community composition; the Methanosarcina proportion decreased 17%, while the Methanosaeta proportion increased 5.6%. Metagenomic analyses based on shotgun sequencing demonstrated that the abundance of pilA and omcS genes belonging to Geobacter species decreased 69.4% and 29.4%, respectively. Furthermore, the analyses suggested a carbon dioxide reduction pathway rather than an acetate decarboxylation pathway for methane formation. Taken together, these results suggest that GAC improved methane production performance by shifting the microbial community and altering functional genes associated with direct interspecies electron transfer via conductive materials. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Direct observation of multistep energy transfer in LHCII with fifth-order 3D electronic spectroscopy.

    Science.gov (United States)

    Zhang, Zhengyang; Lambrev, Petar H; Wells, Kym L; Garab, Győző; Tan, Howe-Siang

    2015-07-31

    During photosynthesis, sunlight is efficiently captured by light-harvesting complexes, and the excitation energy is then funneled towards the reaction centre. These photosynthetic excitation energy transfer (EET) pathways are complex and proceed in a multistep fashion. Ultrafast two-dimensional electronic spectroscopy (2DES) is an important tool to study EET processes in photosynthetic complexes. However, the multistep EET processes can only be indirectly inferred by correlating different cross peaks from a series of 2DES spectra. Here we directly observe multistep EET processes in LHCII using ultrafast fifth-order three-dimensional electronic spectroscopy (3DES). We measure cross peaks in 3DES spectra of LHCII that directly indicate energy transfer from excitons in the chlorophyll b (Chl b) manifold to the low-energy level chlorophyll a (Chl a) via mid-level Chl a energy states. This new spectroscopic technique allows scientists to move a step towards mapping the complete complex EET processes in photosynthetic systems.

  1. The possible role of honey bees in the spread of pollen from field trials

    NARCIS (Netherlands)

    Kleinjans, H.A.W.; Keulen, van S.J.; Blacquière, T.; Booij, C.J.H.; Hok-A-Hin, C.H.; Cornelissen, A.C.M.; Dooremalen, van C.

    2012-01-01

    Honey bees are important pollinators in agricultural crops, home gardens, orchards and wildlife habitats. As they fly from flower to flower in search of nectar and pollen, they transfer pollen from plant to plant, thus fertilizing the plants and enabling them to bear fruit. In light of this, honey

  2. Direct Electron Transfer of Enzymes in a Biologically Assembled Conductive Nanomesh Enzyme Platform.

    Science.gov (United States)

    Lee, Seung-Woo; Lee, Ki-Young; Song, Yong-Won; Choi, Won Kook; Chang, Joonyeon; Yi, Hyunjung

    2016-02-24

    Nondestructive assembly of a nanostructured enzyme platform is developed in combination of the specific biomolecular attraction and electrostatic coupling for highly efficient direct electron transfer (DET) of enzymes with unprecedented applicability and versatility. The biologically assembled conductive nanomesh enzyme platform enables DET-based flexible integrated biosensors and DET of eight different enzyme with various catalytic activities. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Visualization of direct contact heat transfer between water and molten alloy

    International Nuclear Information System (INIS)

    Nishi, Yoshihisa; Furuya, Masahiro; Kinoshita, Izumi; Takenaka, Nobuyuki; Matsubayashi, Masahito.

    1996-01-01

    We have been developing an innovative Steam Generator concept of Fast Breeder Reactors by using liquid-liquid direct contact heat transfer. In this concept, the SG shell is filled with a molten alloys, which is heated by primary sodium. Water is fed into the high temperature molten alloy, and evaporates by direct contact heating. In order to obtain the fundamental information to discuss the heat transfer mechanisms of the direct contact between the water and the alloy, this phenomenon was visualized by real-time neutron radiography. JRR-3M real-time thermal neutron radiography in Japan Atomic Energy Research Institute was used. Followings are main results. (1) The vigorous evaporation occurs in the molten alloy. This phenomena is different from the known phenomenon such as the evaporation of refrigerant R-113 in the water. (2) The evaporation in the bubble has finished in a moment due to high heat transfer performance between the liquid and molten alloy. (3) It is confirmed that the velocity of bubble with the rapid evaporation and growth is about 50 cm/s. (author)

  4. Impact of Implementation of Direct Cash Transfer Program 2008/2009 on Household Consumption in Central Java Province

    Science.gov (United States)

    Subanti, S.; Hakim, A. R.; Hakim, I. M.

    2017-04-01

    This study aims to see the impact of direct cash transfer program for 2008/2009 on household consumption of food, nonfood, education, and health in Central Java Province. The study is expected to provide important findings for the improvement of a similar program in the future. This study findings that (1) the increasing in food and non-food consumption for direct cash transfer recipients than non direct cash transfer recipients; (2) the impact of households expenditure on education for direct cash transfer recipients is higher than non direct cash transfer recipients; (3) the impact of households expenditure on health for direct cash transfer recipients is lower than non direct cash transfer recipients. This study recommended that (1) implementation of direct cash transfer program 2008/2009 must be managed to be better because this program can defend household welfare. It shows from several indicators of well-being such as consumption spending, education, and health; (2) data targets for poor households (very poor, poor, nearly poor) must be updated.

  5. Evaluation of pollen dispersal and cross pollination using transgenic grapevine plants.

    Science.gov (United States)

    Harst, Margit; Cobanov, Beatrix-Axinja; Hausmann, Ludger; Eibach, Rudolf; Töpfer, Reinhard

    2009-01-01

    Public debate about the possible risk of genetically modified plants often concerns putative effects of pollen dispersal and out-crossing into conventional fields in the neighborhood of transgenic plants. Though Vitis vinifera (grapevine) is generally considered to be self-pollinating, it cannot be excluded that vertical gene transfer might occur. For monitoring pollen flow and out-crossing events, transgenic plants of Vitis vinifera cv. 'Dornfelder' harboring the gus-int gene were planted in the center of a field experiment in Southwest Germany in 1999. The rate of pollen dispersal was determined by pollen traps placed at radial distances of 5-150 m from the pollen-donor plants, at 1.00 and 1.80 m above ground. Transgenic pollen was evaluated by GUS staining, and could clearly be distinguished from pollen originating from non-transgenic grapevine plants. Transgenic pollen was observed up to 150 m from the pollen donors. The rate of out-crossing was determined by sampling seeds of selected grapevines at a distance of 10 m to the pollen source, and of a sector at 20 m distance, respectively, followed by GUS analysis of seedlings. The average cross-pollination rate during the experiment (2002-2004) was 2.7% at a distance of 20 m. The results of this first pilot study present a good base for further assessment under the conditions of normal viticulture practice.

  6. Post-X-irradiation effects on petunia pollen germinating in vitro and in vivo

    International Nuclear Information System (INIS)

    Gilissen, L.J.W.

    1978-01-01

    The germination of Petunia hybrida L. pollen grains in germination medium, containing 10% sucrose and 0.01 % H 3 BO 3 , was linearly related to relative humidity (RH): being minimal at 0 % RH and maximal at 100 % RH. The low germination at 0 % RH was completely restored after transfer to 100 % RH. Germination in medium decreased with increasing X-ray exposures between O and 400 kR. This decrease was caused by pollen rupture. No in vitro germination occurred at exposures of 400 kR and more. The radiosensitivity of pollen in vitro was minimal at 80 % RH. Transfer of pollen to the stigma post-X-irradiation resulted in resistance to much higher exposures of irradiation (<750 kR). The differences in radiosensitivity of the pollen germinated in vitro and in vivo are due possibly to the differences in composition of the germination medium and the stigmatic exudate. Pollen tube growth of irradiated pollen after compatible or incompatible pollination at first showed retarded then normal tube growth. A conclusion is that X-irradiation of pollen cannot influence the characteristics of pollen tube growth after compatible or incompatible pollination. (author)

  7. pH-dependent electron transfer reaction and direct bioelectrocatalysis of the quinohemoprotein pyranose dehydrogenase

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Kouta [Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); Matsumura, Hirotoshi; Ishida, Takuya [Department of Biomaterial Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657 (Japan); Yoshida, Makoto [Department of Environmental and Natural Resource Science, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509 (Japan); Igarashi, Kiyohiko; Samejima, Masahiro [Department of Biomaterial Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657 (Japan); Ohno, Hiroyuki [Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); Nakamura, Nobuhumi, E-mail: nobu1@cc.tuat.ac.jp [Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan)

    2016-08-26

    A pyranose dehydrogenase from Coprinopsis cinerea (CcPDH) is an extracellular quinohemoeprotein, which consists a b-type cytochrome domain, a pyrroloquinoline-quinone (PQQ) domain, and a family 1-type carbohydrate-binding module. The electron transfer reaction of CcPDH was studied using some electron acceptors and a carbon electrode at various pH levels. Phenazine methosulfate (PMS) reacted directly at the PQQ domain, whereas cytochrome c (cyt c) reacted via the cytochrome domain of intact CcPDH. Thus, electrons are transferred from reduced PQQ in the catalytic domain of CcPDH to heme b in the N-terminal cytochrome domain, which acts as a built-in mediator and transfers electron to a heterogenous electron transfer protein. The optimal pH values of the PMS reduction (pH 6.5) and the cyt c reduction (pH 8.5) differ. The catalytic currents for the oxidation of L-fucose were observed within a range of pH 4.5 to 11. Bioelectrocatalysis of CcPDH based on direct electron transfer demonstrated that the pH profile of the biocatalytic current was similar to the reduction activity of cyt c characters. - Highlights: • pH dependencies of activity were different for the reduction of cyt c and DCPIP. • DET-based bioelectrocatalysis of CcPDH was observed. • The similar pH-dependent profile was found with cyt c and electrode. • The present results suggested that IET reaction of CcPDH shows pH dependence.

  8. Transfer Entropy Estimation and Directional Coupling Change Detection in Biomedical Time Series

    Directory of Open Access Journals (Sweden)

    Lee Joon

    2012-04-01

    Full Text Available Abstract Background The detection of change in magnitude of directional coupling between two non-linear time series is a common subject of interest in the biomedical domain, including studies involving the respiratory chemoreflex system. Although transfer entropy is a useful tool in this avenue, no study to date has investigated how different transfer entropy estimation methods perform in typical biomedical applications featuring small sample size and presence of outliers. Methods With respect to detection of increased coupling strength, we compared three transfer entropy estimation techniques using both simulated time series and respiratory recordings from lambs. The following estimation methods were analyzed: fixed-binning with ranking, kernel density estimation (KDE, and the Darbellay-Vajda (D-V adaptive partitioning algorithm extended to three dimensions. In the simulated experiment, sample size was varied from 50 to 200, while coupling strength was increased. In order to introduce outliers, the heavy-tailed Laplace distribution was utilized. In the lamb experiment, the objective was to detect increased respiratory-related chemosensitivity to O2 and CO2 induced by a drug, domperidone. Specifically, the separate influence of end-tidal PO2 and PCO2 on minute ventilation (V˙E before and after administration of domperidone was analyzed. Results In the simulation, KDE detected increased coupling strength at the lowest SNR among the three methods. In the lamb experiment, D-V partitioning resulted in the statistically strongest increase in transfer entropy post-domperidone for PO2→V˙E. In addition, D-V partitioning was the only method that could detect an increase in transfer entropy for PCO2→V˙E, in agreement with experimental findings. Conclusions Transfer entropy is capable of detecting directional coupling changes in non-linear biomedical time series analysis featuring a small number of observations and presence of outliers. The results

  9. Direct CVD Graphene Growth on Semiconductors and Dielectrics for Transfer-Free Device Fabrication.

    Science.gov (United States)

    Wang, Huaping; Yu, Gui

    2016-07-01

    Graphene is the most broadly discussed and studied two-dimensional material because of its preeminent physical, mechanical, optical, and thermal properties. Until now, metal-catalyzed chemical vapor deposition (CVD) has been widely employed for the scalable production of high-quality graphene. However, in order to incorporate the graphene into electronic devices, a transfer process from metal substrates to targeted substrates is inevitable. This process usually results in contamination, wrinkling, and breakage of graphene samples - undesirable in graphene-based technology and not compatible with industrial production. Therefore, direct graphene growth on desired semiconductor and dielectric substrates is considered as an effective alternative. Over the past years, there have been intensive investigations to realize direct graphene growth using CVD methods without the catalytic role of metals. Owing to the low catalytic activity of non-metal substrates for carbon precursor decomposition and graphene growth, several strategies have been designed to facilitate and engineer graphene fabrication on semiconductors and insulators. Here, those developed strategies for direct CVD graphene growth on semiconductors and dielectrics for transfer-free fabrication of electronic devices are reviewed. By employing these methods, various graphene-related structures can be directly prepared on desired substrates and exhibit excellent performance, providing versatile routes for varied graphene-based materials fabrication. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Nursing protects honeybee larvae from secondary metabolites of pollen.

    Science.gov (United States)

    Lucchetti, Matteo A; Kilchenmann, Verena; Glauser, Gaetan; Praz, Christophe; Kast, Christina

    2018-03-28

    The pollen of many plants contains toxic secondary compounds, sometimes in concentrations higher than those found in the flowers or leaves. The ecological significance of these compounds remains unclear, and their impact on bees is largely unexplored. Here, we studied the impact of pyrrolizidine alkaloids (PAs) found in the pollen of Echium vulgare on honeybee adults and larvae. Echimidine, a PA present in E. vulgare pollen, was isolated and added to the honeybee diets in order to perform toxicity bioassays. While adult bees showed relatively high tolerance to PAs, larvae were much more sensitive. In contrast to other bees, the honeybee larval diet typically contains only traces of pollen and consists predominantly of hypopharyngeal and mandibular secretions produced by nurse bees, which feed on large quantities of pollen-containing bee bread. We quantified the transfer of PAs to nursing secretions produced by bees that had previously consumed bee bread supplemented with PAs. The PA concentration in these secretions was reduced by three orders of magnitude as compared to the PA content in the nurse diet and was well below the toxicity threshold for larvae. Our results suggest that larval nursing protects honeybee larvae from the toxic effect of secondary metabolites of pollen. © 2018 The Authors.

  11. Nursing protects honeybee larvae from secondary metabolites of pollen

    Science.gov (United States)

    Lucchetti, Matteo A.; Kilchenmann, Verena; Glauser, Gaetan; Praz, Christophe

    2018-01-01

    The pollen of many plants contains toxic secondary compounds, sometimes in concentrations higher than those found in the flowers or leaves. The ecological significance of these compounds remains unclear, and their impact on bees is largely unexplored. Here, we studied the impact of pyrrolizidine alkaloids (PAs) found in the pollen of Echium vulgare on honeybee adults and larvae. Echimidine, a PA present in E. vulgare pollen, was isolated and added to the honeybee diets in order to perform toxicity bioassays. While adult bees showed relatively high tolerance to PAs, larvae were much more sensitive. In contrast to other bees, the honeybee larval diet typically contains only traces of pollen and consists predominantly of hypopharyngeal and mandibular secretions produced by nurse bees, which feed on large quantities of pollen-containing bee bread. We quantified the transfer of PAs to nursing secretions produced by bees that had previously consumed bee bread supplemented with PAs. The PA concentration in these secretions was reduced by three orders of magnitude as compared to the PA content in the nurse diet and was well below the toxicity threshold for larvae. Our results suggest that larval nursing protects honeybee larvae from the toxic effect of secondary metabolites of pollen. PMID:29563265

  12. Application of Direct Assessment Approaches and Methodologies to Cathodically Protected Nuclear Waste Transfer Lines

    International Nuclear Information System (INIS)

    Dahl, Megan M.; Pikas, Joseph; Edgemon, Glenn L.; Philo, Sarah

    2013-01-01

    The U.S. Department of Energy's (DOE) Hanford Site is responsible for the safe storage, retrieval, treatment, and disposal of approximately 54 million gallons (204 million liters) of radioactive waste generated since the site's inception in 1943. Today, the major structures involved in waste management at Hanford include 149 carbon steel single-shell tanks, 28 carbon-steel double-shell tanks, plus a network of buried metallic transfer lines and ancillary systems (pits, vaults, catch tanks, etc.) required to store, retrieve, and transfer waste within the tank farm system. Many of the waste management systems at Hanford are still in use today. In response to uncertainties regarding the structural integrity of these systems,' an independent, comprehensive integrity assessment of the Hanford Site piping system was performed. It was found that regulators do not require the cathodically protected pipelines located within the Hanford Site to be assessed by External Corrosion Direct Assessment (ECDA) or any other method used to ensure integrity. However, a case study is presented discussing the application of the direct assessment process on pipelines in such a nuclear environment. Assessment methodology and assessment results are contained herein. An approach is described for the monitoring, integration of outside data, and analysis of this information in order to identify whether coating deterioration accompanied by external corrosion is a threat for these waste transfer lines

  13. Nursing performance in the policy transfer of directly observed treatment of tuberculosis

    Directory of Open Access Journals (Sweden)

    Káren Mendes Jorge de Souza

    2014-10-01

    Full Text Available Objective Analyzing the policy transfer of directly observed treatment of tuberculosis from the perspective of nursing. Method This is a descriptive study with qualitative approach, which had 10 nurses of the Family Health Strategy in São Paulo as subjects. The interviews were carried out between May and June 2013, and were adopted the technique of thematic content analysis and the referential of policy transfer. Results On the signification of this treatment, are related the senses of disciplinary monitoring, the bond and approximation to the context of patients’ lives. Operationally, nurses, community health agents and nursing technicians stand out as agents of implementation of this policy, developing multiple actions of user embracement. The nurse is evidenced as an educator in health, leader in the family health team, and capable of creating emotional bond with users. Conclusion It was found that the innovations proposed in the treatment are incipient in the daily work of nurses.

  14. [Nursing performance in the policy transfer of directly observed treatment of tuberculosis].

    Science.gov (United States)

    Souza, Káren Mendes Jorge de; Sá, Lenilde Duarte de; Silva, Laís Mara Caetano da; Palha, Pedro Fredemir

    2014-10-01

    Analyzing the policy transfer of directly observed treatment of tuberculosis from the perspective of nursing. This is a descriptive study with qualitative approach, which had 10 nurses of the Family Health Strategy in São Paulo as subjects. The interviews were carried out between May and June 2013, and were adopted the technique of thematic content analysis and the referential of policy transfer. On the signification of this treatment, are related the senses of disciplinary monitoring, the bond and approximation to the context of patients' lives. Operationally, nurses, community health agents and nursing technicians stand out as agents of implementation of this policy, developing multiple actions of user embracement. The nurse is evidenced as an educator in health, leader in the family health team, and capable of creating emotional bond with users. It was found that the innovations proposed in the treatment are incipient in the daily work of nurses.

  15. A direct metal transfer method for cross-bar type polymer non-volatile memory applications

    International Nuclear Information System (INIS)

    Kim, Tae-Wook; Lee, Kyeongmi; Oh, Seung-Hwan; Wang, Gunuk; Kim, Dong-Yu; Jung, Gun-Young; Lee, Takhee

    2008-01-01

    Polymer non-volatile memory devices in 8 x 8 array cross-bar architecture were fabricated by a non-aqueous direct metal transfer (DMT) method using a two-step thermal treatment. Top electrodes with a linewidth of 2 μm were transferred onto the polymer layer by the DMT method. The switching behaviour of memory devices fabricated by the DMT method was very similar to that of devices fabricated by the conventional shadow mask method. The devices fabricated using the DMT method showed three orders of magnitude of on/off ratio with stable resistance switching, demonstrating that the DMT method can be a simple process to fabricate organic memory array devices

  16. Wave packet methods for the direct calculation of energy-transfer moments in molecular collisions

    International Nuclear Information System (INIS)

    Bradley, K.S.; Schatz, G.C.; Balint-Kurti, G.G.

    1999-01-01

    The authors present a new wave packet based theory for the direct calculation of energy-transfer moments in molecular collision processes. This theory does not contain any explicit reference to final state information associated with the collision dynamics, thereby avoiding the need for determining vibration-rotation bound states (other than the initial state) for the molecules undergoing collision and also avoiding the calculation of state-to-state transition probabilities. The theory applies to energy-transfer moments of any order, and it generates moments for a wide range of translational energies in a single calculation. Two applications of the theory are made that demonstrate its viability; one is to collinear He + H 2 and the other to collinear He + CS 2 (with two active vibrational modes in CS 2 ). The results of these applications agree well with earlier results based on explicit calculation of transition probabilities

  17. Pollen characteristics and in vitro pollen germination of Cedrus ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-11-02

    Nov 2, 2009 ... This study aims to determine the germination characteristics, pollen tube developments, effects of germination media and temperature and incubation durations of the pollens obtained from the four clones (11342, 11344, 11345 and 11351) of Cedrus libani A. Rich. (Lebanon Cedrus) obtained from clonal.

  18. The stylar 120 kDa glycoprotein is required for S-specific pollen rejection in Nicotiana.

    Science.gov (United States)

    Hancock, C Nathan; Kent, Lia; McClure, Bruce A

    2005-09-01

    S-RNase participates in at least three mechanisms of pollen rejection. It functions in S-specific pollen rejection (self-incompatibility) and in at least two distinct interspecific mechanisms of pollen rejection in Nicotiana. S-specific pollen rejection and rejection of pollen from Nicotiana plumbaginifolia also require additional stylar proteins. Transmitting-tract-specific (TTS) protein, 120 kDa glycoprotein (120K) and pistil extensin-like protein III (PELP III) are stylar glycoproteins that bind S-RNase in vitro and are also known to interact with pollen. Here we tested whether these glycoproteins have a direct role in pollen rejection. 120K shows the most polymorphism in size between Nicotiana species. Larger 120K-like proteins are often correlated with S-specific pollen rejection. Sequencing results suggest that the polymorphism primarily reflects differences in glycosylation, although indels also occur in the predicted polypeptides. Using RNA interference (RNAi), we suppressed expression of 120K to determine if it is required for S-specific pollen rejection. Transgenic SC N. plumbaginifolia x SI Nicotiana alata (S105S105 or SC10SC10) hybrids with no detectable 120K were unable to perform S-specific pollen rejection. Thus, 120K has a direct role in S-specific pollen rejection. However, suppression of 120K had no effect on rejection of N. plumbaginifolia pollen. In contrast, suppression of HT-B, a factor previously implicated in S-specific pollen rejection, disrupts rejection of N. plumbaginifolia pollen. Thus, S-specific pollen rejection and rejection of N. plumbaginifolia pollen are mechanistically distinct, because they require different non-S-RNase factors.

  19. Direct Collapse to Supermassive Black Hole Seeds with Radiation Transfer: Cosmological Halos

    Science.gov (United States)

    Ardaneh, Kazem; Luo, Yang; Shlosman, Isaac; Nagamine, Kentaro; Wise, John H.; Begelman, Mitchell C.

    2018-06-01

    We have modeled direct collapse of a primordial gas within dark matter halos in the presence of radiative transfer, in high-resolution zoom-in simulations in a cosmological framework, down to the formation of the photosphere and the central object. Radiative transfer has been implemented in the flux-limited diffusion (FLD) approximation. Adiabatic models were run for comparison. We find that (a) the FLD flow forms an irregular central structure and does not exhibit fragmentation, contrary to adiabatic flow which forms a thick disk, driving a pair of spiral shocks, subject to Kelvin-Helmholtz shear instability forming fragments; (b) the growing central core in the FLD flow quickly reaches ˜10 M⊙ and a highly variable luminosity of 1038 - 1039 erg s-1, comparable to the Eddington luminosity. It experiences massive recurrent outflows driven by radiation force and thermal pressure gradients, which mix with the accretion flow and transfer the angular momentum outwards; and (c) the interplay between these processes and a massive accretion, results in photosphere at ˜10 AU. We conclude that in the FLD model (1) the central object exhibits dynamically insignificant rotation and slower than adiabatic temperature rise with density; (2) does not experience fragmentation leading to star formation, thus promoting the fast track formation of a supermassive black hole (SMBH) seed; (3) inclusion of radiation force leads to outflows, resulting in the mass accumulation within the central 10-3 pc, which is ˜100 times larger than characteristic scale of star formation. The inclusion of radiative transfer reveals complex early stages of formation and growth of the central structure in the direct collapse scenario of SMBH seed formation.

  20. Metal-etching-free direct delamination and transfer of single-layer graphene with a high degree of freedom.

    Science.gov (United States)

    Yang, Sang Yoon; Oh, Joong Gun; Jung, Dae Yool; Choi, HongKyw; Yu, Chan Hak; Shin, Jongwoo; Choi, Choon-Gi; Cho, Byung Jin; Choi, Sung-Yool

    2015-01-14

    A method of graphene transfer without metal etching is developed to minimize the contamination of graphene in the transfer process and to endow the transfer process with a greater degree of freedom. The method involves direct delamination of single-layer graphene from a growth substrate, resulting in transferred graphene with nearly zero Dirac voltage due to the absence of residues that would originate from metal etching. Several demonstrations are also presented to show the high degree of freedom and the resulting versatility of this transfer method. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. A concentrated solar cavity absorber with direct heat transfer through recirculating metallic particles

    Energy Technology Data Exchange (ETDEWEB)

    Sarker, M. R. I., E-mail: islamrabiul@yahoo.com; Saha, Manabendra, E-mail: manabendra.saha@adelaide.edu.au, E-mail: manab04me@gmail.com; Beg, R. A. [Department of Mechanical Engineering, Rajshahi University of Engineering and Technology, Rajshahi-6204 (Bangladesh)

    2016-07-12

    A recirculating flow solar particle cavity absorber (receiver) is modeled to investigate the flow behavior and heat transfer characteristics of a novel developing concept. It features a continuous recirculating flow of non-reacting metallic particles (black silicon carbide) with air which are used as a thermal enhancement medium. The aim of the present study is to numerically investigate the thermal behavior and flow characteristics of the proposed concept. The proposed solar particle receiver is modeled using two phase discrete particle model (DPM), RNG k-flow model and discrete ordinate (DO) radiation model. Numerical analysis is carried out considering a solar receiver with only air and the mixture of non-reacting particles and air as a heat transfer as well as heat carrying medium. The parametric investigation is conducted considering the incident solar flux on the receiver aperture and changing air flow rate and recirculation rate inside the receiver. A stand-alone feature of the recirculating flow solar particle receiver concept is that the particles are directly exposed to concentrated solar radiation monotonously through recirculating flow inside the receiver and results in efficient irradiation absorption and convective heat transfer to air that help to achieve high temperature air and consequently increase in thermal efficiency. This paper presents, results from the developed concept and highlights its flow behavior and potential to enhance the heat transfer from metallic particles to air by maximizing heat carrying capacity of the heat transfer medium. The imposed milestones for the present system will be helpful to understand the radiation absorption mechanism of the particles in a recirculating flow based receiver, the thermal transport between the particles, the air and the cavity, and the fluid dynamics of the air and particle in the cavity.

  2. A direct healthcare cost analysis of the cryopreserved versus fresh transfer policy at the blastocyst stage.

    Science.gov (United States)

    Papaleo, Enrico; Pagliardini, Luca; Vanni, Valeria Stella; Delprato, Diana; Rubino, Patrizia; Candiani, Massimo; Viganò, Paola

    2017-01-01

    A cost analysis covering direct healthcare costs relating to IVF freeze-all policy was conducted. Normal- and high- responder patients treated with a freeze-all policy (n = 63) compared with fresh transfer IVF (n = 189) matched by age, body mass index, duration and cause of infertility, predictive factors for IVF (number of oocytes used for fertilization) and study period, according to a 1:3 ratio were included. Total costs per patient (€6952 versus €6863) and mean costs per live birth were similar between the freeze-all strategy (€13,101, 95% CI 10,686 to 17,041) and fresh transfer IVF (€15,279, 95% CI 13,212 to 18,030). A mean per live birth cost-saving of €2178 (95% CI -1810 to 6165) resulted in a freeze-all strategy owing to fewer embryo transfer procedures (1.29 ± 0.5 versus 1.41 ± 0.7); differences were not significant. Sensitivity analysis revealed that the freeze-all strategy remained cost-effective until the live birth rate is either higher or only slightly lower (≥-0.59%) in the freeze-all group compared with fresh cycles. A freeze-all policy does not increase costs compared with fresh transfer, owing to negligible additional expenses, i.e. vitrification, endometrial priming and monitoring, against fewer embryo transfer procedures required to achieve pregnancy. Copyright © 2016 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

  3. Powering microbes with electricity: direct electron transfer from electrodes to microbes.

    Science.gov (United States)

    Lovley, Derek R

    2011-02-01

    The discovery of electrotrophs, microorganisms that can directly accept electrons from electrodes for the reduction of terminal electron acceptors, has spurred the investigation of a wide range of potential applications. To date, only a handful of pure cultures have been shown to be capable of electrotrophy, but this process has also been inferred in many studies with undefined consortia. Potential electron acceptors include: carbon dioxide, nitrate, metals, chlorinated compounds, organic acids, protons and oxygen. Direct electron transfer from electrodes to cells has many advantages over indirect electrical stimulation of microbial metabolism via electron shuttles or hydrogen production. Supplying electrons with electrodes for the bioremediation of chlorinated compounds, nitrate or toxic metals may be preferable to adding organic electron donors or hydrogen to the subsurface or bioreactors. The most transformative application of electrotrophy may be microbial electrosynthesis in which carbon dioxide and water are converted to multi-carbon organic compounds that are released extracellularly. Coupling photovoltaic technology with microbial electrosynthesis represents a novel photosynthesis strategy that avoids many of the drawbacks of biomass-based strategies for the production of transportation fuels and other organic chemicals. The mechanisms for direct electron transfer from electrodes to microorganisms warrant further investigation in order to optimize envisioned applications. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

  4. Cytochrome P450BM-3 reduces aldehydes to alcohols through a direct hydride transfer

    Energy Technology Data Exchange (ETDEWEB)

    Kaspera, Ruediger; Sahele, Tariku; Lakatos, Kyle [Department of Medicinal Chemistry, University of Washington, Box 357610, Seattle, WA 98195-7610 (United States); Totah, Rheem A., E-mail: rtotah@u.washington.edu [Department of Medicinal Chemistry, University of Washington, Box 357610, Seattle, WA 98195-7610 (United States)

    2012-02-17

    Highlights: Black-Right-Pointing-Pointer Cytochrome P450BM-3 reduced aldehydes to alcohols efficiently (k{sub cat} {approx} 25 min{sup -1}). Black-Right-Pointing-Pointer Reduction is a direct hydride transfer from R-NADP{sup 2}H to the carbonyl moiety. Black-Right-Pointing-Pointer P450 domain variants enhance reduction through potential allosteric/redox interactions. Black-Right-Pointing-Pointer Novel reaction will have implications for metabolism of xenobiotics. -- Abstract: Cytochrome P450BM-3 catalyzed the reduction of lipophilic aldehydes to alcohols efficiently. A k{sub cat} of {approx}25 min{sup -1} was obtained for the reduction of methoxy benzaldehyde with wild type P450BM-3 protein which was higher than in the isolated reductase domain (BMR) alone and increased in specific P450-domain variants. The reduction was caused by a direct hydride transfer from preferentially R-NADP{sup 2}H to the carbonyl moiety of the substrate. Weak substrate-P450-binding of the aldehyde, turnover with the reductase domain alone, a deuterium incorporation in the product from NADP{sup 2}H but not D{sub 2}O, and no inhibition by imidazole suggests the reductase domain of P450BM-3 as the potential catalytic site. However, increased aldehyde reduction by P450 domain variants (P450BM-3 F87A T268A) may involve allosteric or redox mechanistic interactions between heme and reductase domains. This is a novel reduction of aldehydes by P450BM-3 involving a direct hydride transfer and could have implications for the metabolism of endogenous substrates or xenobiotics.

  5. Cytochrome P450BM-3 reduces aldehydes to alcohols through a direct hydride transfer

    International Nuclear Information System (INIS)

    Kaspera, Rüdiger; Sahele, Tariku; Lakatos, Kyle; Totah, Rheem A.

    2012-01-01

    Highlights: ► Cytochrome P450BM-3 reduced aldehydes to alcohols efficiently (k cat ∼ 25 min −1 ). ► Reduction is a direct hydride transfer from R-NADP 2 H to the carbonyl moiety. ► P450 domain variants enhance reduction through potential allosteric/redox interactions. ► Novel reaction will have implications for metabolism of xenobiotics. -- Abstract: Cytochrome P450BM-3 catalyzed the reduction of lipophilic aldehydes to alcohols efficiently. A k cat of ∼25 min −1 was obtained for the reduction of methoxy benzaldehyde with wild type P450BM-3 protein which was higher than in the isolated reductase domain (BMR) alone and increased in specific P450-domain variants. The reduction was caused by a direct hydride transfer from preferentially R-NADP 2 H to the carbonyl moiety of the substrate. Weak substrate-P450-binding of the aldehyde, turnover with the reductase domain alone, a deuterium incorporation in the product from NADP 2 H but not D 2 O, and no inhibition by imidazole suggests the reductase domain of P450BM-3 as the potential catalytic site. However, increased aldehyde reduction by P450 domain variants (P450BM-3 F87A T268A) may involve allosteric or redox mechanistic interactions between heme and reductase domains. This is a novel reduction of aldehydes by P450BM-3 involving a direct hydride transfer and could have implications for the metabolism of endogenous substrates or xenobiotics.

  6. Direct gene transfer in the Gottingen minipig CNS using stereotaxic lentiviral microinjections

    DEFF Research Database (Denmark)

    GLUD, AN; Hedegaard, Claus; Nielsen, Mette Slot

    2010-01-01

    We aim to induce direct viral mediated gene transfer in the substantia nigra (SN) of the Gottingen minipig using MRI guided stereotaxic injections of lentiviral vectors encoding enhanced green fluorescent protein (EGFP). Nine female Gottingen minipigs were injected unilaterally into the SN with 6...... per 2.5 microliters lentivirus capable of transducing cells and mediating expression of recombinant EGFP. The animals were euthanized after four (n=3) or twenty weeks (n=6). Fresh brain tissue from three animals was used for PCR. The remaining six brains were cryo- or paraffin...

  7. A Direct Radiative Transfer Equation Solver for Path Loss Calculation of Underwater Optical Wireless Channels

    KAUST Repository

    Li, Changping

    2014-11-10

    In this report, we propose a fast numerical solution for the steady state radiative transfer equation in order to calculate the path loss due to light absorption and scattering in various type of underwater channels. In the proposed scheme, we apply a direct non-uniform method to discretize the angular space and an upwind type finite difference method to discretize the spatial space. A Gauss-Seidel iterative method is then applied to solve the fully discretized system of linear equations. The accuracy and efficiency of the proposed scheme is validated by Monte Carlo simulations.

  8. A Direct Radiative Transfer Equation Solver for Path Loss Calculation of Underwater Optical Wireless Channels

    KAUST Repository

    Li, Changping; Park, Ki-Hong; Alouini, Mohamed-Slim

    2014-01-01

    In this report, we propose a fast numerical solution for the steady state radiative transfer equation in order to calculate the path loss due to light absorption and scattering in various type of underwater channels. In the proposed scheme, we apply a direct non-uniform method to discretize the angular space and an upwind type finite difference method to discretize the spatial space. A Gauss-Seidel iterative method is then applied to solve the fully discretized system of linear equations. The accuracy and efficiency of the proposed scheme is validated by Monte Carlo simulations.

  9. Estimation of instantaneous heat transfer coefficients for a direct-injection stratified-charge rotary engine

    Science.gov (United States)

    Lee, C. M.; Addy, H. E.; Bond, T. H.; Chun, K. S.; Lu, C. Y.

    1987-01-01

    The main objective of this report was to derive equations to estimate heat transfer coefficients in both the combustion chamber and coolant pasage of a rotary engine. This was accomplished by making detailed temperature and pressure measurements in a direct-injection stratified-charge rotary engine under a range of conditions. For each sppecific measurement point, the local physical properties of the fluids were calculated. Then an empirical correlation of the coefficients was derived by using a multiple regression program. This correlation expresses the Nusselt number as a function of the Prandtl number and Reynolds number.

  10. A digital computer simulation and study of a direct-energy-transfer power-conditioning system

    Science.gov (United States)

    Burns, W. W., III; Owen, H. A., Jr.; Wilson, T. G.; Rodriguez, G. E.; Paulkovich, J.

    1975-01-01

    An investigation of the behavior of the power-conditioning system as a whole is a necessity to ensure the integrity of the aggregate system in the case of space applications. An approach for conducting such an investigation is considered. A description is given of the application of a general digital analog simulator program to the study of an aggregate power-conditioning system which is being developed for use on the International Ultraviolet Explorer spacecraft. The function of the direct energy transfer system studied involves a coupling of a solar array through a main distribution bus to the spacecraft electrical loads.

  11. Transfer by anisotropic scattering between subsets of the unit sphere of directions in linear transport theory

    International Nuclear Information System (INIS)

    Trombetti, T.

    1990-01-01

    The exact kernel method is presented for linear transport problems with azimuth-dependent angular fluxes. It is based on the evaluation of average scattering densities (ASD's) that fully describe the neutron (or particle) transfer between subsets of the unit sphere of directions by anisotropic scattering. Reciprocity and other ASD functional properties are proved and combined with the symmetry properties of suitable SN quadrature sets. This greatly reduces the number of independent ASD's to be computed and stored. An approach for performing ASD computations with reciprocity checks is presented. ASD expressions of the scattering source for typical 2D geometries are explicitly given. (author)

  12. Pollen morphology of the Alangiaceae

    NARCIS (Netherlands)

    Reitsma, Tj.

    1970-01-01

    This paper presents a pollen-morphological study of Alangium, a genus mainly restricted to the tropics of the Old World, of which 18 of the 19 known species were studied. The pollen grains, studied with the use of a light microscope, a transmission electron microscope and a scanning electron

  13. Allergenic pollen pollinosis in Madrid.

    Science.gov (United States)

    Subiza, J; Jerez, M; Jiménez, J A; Narganes, M J; Cabrera, M; Varela, S; Subiza, E

    1995-07-01

    A 15-year pollen count was performed in the atmosphere of Madrid, Spain, to determine the months in which the highest concentrations of allergenic pollens occur. Pollen counts were done with a Burkard spore trap (Burkard Manufacturing, Rickmansworth, Herst., U.K.). The results were subsequently compared with results of skin tests in patients with pollinosis born and living in and around Madrid. The highest airborne presence (percent of total yearly pollen counts, mean of counts from 1979 to 1993) was for Quercus spp. (17%); followed by Platanus spp. (15%), Poaceae (15%), Cupressaceae (11%), Olea spp. (9%), Pinus spp. (7%), Populus spp. (4%), and Plantago spp. (4%). The most predominant pollens from January to April are tree pollens (Cupressaceae, Alnus, Fraxinus, Ulmus, Populus, Platanus, and Morus), although these are also abudant in May and June (Quercus, Olea, and Pinus spp.). The grass pollination period shows a double curve: the first peak occurs from February to April (8% of yearly grasses), and the second peak occurs from May to July (90% of yearly grasses). Among allergenically significant weeds, the most notable is Plantago; in contrast, Rumex, Urticaceae, Cheno-Amaranthaceae, and Artemisia spp. have very low concentrations (arizonica (20%). The population of Madrid is exposed to high concentrations of allergenic pollen from February to July, although the most intense period is from May to June. Grass pollens are the most important cause of pollinosis in this area.

  14. Impacts of air pollution exposure on the allergenic properties of Arizona cypress pollens

    Energy Technology Data Exchange (ETDEWEB)

    Shahali, Y; Pourpak, Z; Moin, M; Zare, A [Immunology, Asthma and Allergy Research Institute, Medical Sciences/ University of Tehran (Iran, Islamic Republic of); Majd, A, E-mail: youcef.shahali@espci.f [Department of Biology, Faculty of Sciences, Islamic Azad University, North Tehran Branch (Iran, Islamic Republic of)

    2009-02-01

    Epidemiological studies have demonstrated that urbanization and high levels of vehicle emissions correlated with the increasing trend of pollen-induced respiratory allergies. Numerous works have investigated the role of pollutants in the pathogenesis of respiratory diseases but impacts of anthropogenic pollution on pollen allergenic properties are still poorly understood. The objective of this survey was to evaluate impacts of the traffic-related pollution on the structure and allergenic protein content of Arizona cypress (Cupressus arizonica, CA) pollens, recognized as a rising cause of seasonal allergy in various regions worldwide. According to our results, traffic-related air pollution by its direct effects on the elemental composition of pollens considerably increased the fragility of the pollen exine, causing numerous cracks in its surface and facilitating pollen content liberation. Pollen grains were also covered by numerous submicronic orbicules which may act as effective vectors for pollen-released components into the lower regions of respiratory organs. On the other hand, this study provides us reliable explications about the low efficiency of standard commercial allergens in the diagnosis of the Arizona cypress pollen allergy in Tehran. Although traffic related pollution affects the allergenic components of CA pollens, the repercussions on the respiratory health of urban populations have yet to be clarified and need further investigations.

  15. Pollen extracts and constituent sugars increase growth of a trypanosomatid parasite of bumble bees

    Directory of Open Access Journals (Sweden)

    Evan C. Palmer-Young

    2017-05-01

    Full Text Available Phytochemicals produced by plants, including at flowers, function in protection against plant diseases, and have a long history of use against trypanosomatid infection. Floral nectar and pollen, the sole food sources for many species of insect pollinators, contain phytochemicals that have been shown to reduce trypanosomatid infection in bumble and honey bees when fed as isolated compounds. Nectar and pollen, however, consist of phytochemical mixtures, which can have greater antimicrobial activity than do single compounds. This study tested the hypothesis that pollen extracts would inhibit parasite growth. Extracts of six different pollens were tested for direct inhibitory activity against cell cultures of the bumble bee trypanosomatid gut parasite Crithidia bombi. Surprisingly, pollen extracts increased parasite growth rather than inhibiting it. Pollen extracts contained high concentrations of sugars, mainly the monosaccharides glucose and fructose. Experimental manipulations of growth media showed that supplemental monosaccharides (glucose and fructose increased maximum cell density, while a common floral phytochemical (caffeic acid with inhibitory activity against other trypanosomatids had only weak inhibitory effects on Crithidia bombi. These results indicate that, although pollen is essential for bees and other pollinators, pollen may promote growth of intestinal parasites that are uninhibited by pollen phytochemicals and, as a result, can benefit from the nutrients that pollen provides.

  16. Impacts of air pollution exposure on the allergenic properties of Arizona cypress pollens

    International Nuclear Information System (INIS)

    Shahali, Y; Pourpak, Z; Moin, M; Zare, A; Majd, A

    2009-01-01

    Epidemiological studies have demonstrated that urbanization and high levels of vehicle emissions correlated with the increasing trend of pollen-induced respiratory allergies. Numerous works have investigated the role of pollutants in the pathogenesis of respiratory diseases but impacts of anthropogenic pollution on pollen allergenic properties are still poorly understood. The objective of this survey was to evaluate impacts of the traffic-related pollution on the structure and allergenic protein content of Arizona cypress (Cupressus arizonica, CA) pollens, recognized as a rising cause of seasonal allergy in various regions worldwide. According to our results, traffic-related air pollution by its direct effects on the elemental composition of pollens considerably increased the fragility of the pollen exine, causing numerous cracks in its surface and facilitating pollen content liberation. Pollen grains were also covered by numerous submicronic orbicules which may act as effective vectors for pollen-released components into the lower regions of respiratory organs. On the other hand, this study provides us reliable explications about the low efficiency of standard commercial allergens in the diagnosis of the Arizona cypress pollen allergy in Tehran. Although traffic related pollution affects the allergenic components of CA pollens, the repercussions on the respiratory health of urban populations have yet to be clarified and need further investigations.

  17. Direct electron transfer of horseradish peroxidase on Nafion-cysteine modified gold electrode

    International Nuclear Information System (INIS)

    Hong, Jun; Moosavi-Movahedi, Ali Akbar; Ghourchian, Hedayatollah; Rad, Ahmad Molaei; Rezaei-Zarchi, Saeed

    2007-01-01

    Direct electron transfer of horseradish peroxidase, immobilized on a functional membrane-modified gold electrode, was studied. The electrode showed a quasi-reversible electrochemical redox behavior with a formal potential of 60mV (versus Ag/AgCl) in 20mM potassium phosphate buffer solution at pH 7.0 and temperature 25 o C. The cathodic transfer coefficient was 0.42 and electron transfer rate constant was evaluated to be 1.6s -1 . Furthermore, the modified electrode was used as a biosensor and exhibited a satisfactory stability and sensitivity to H 2 O 2 . The linear range of this biosensor for H 2 O 2 determination was from 5.0x10 -6 to 1.5x10 -4 M while its detection limit, based on a signal-to-noise ratio of 3, was 1.3x10 -6 M. The apparent Michaelis-Menten constant (K m app ) for immobilized HRP was calculated to be 1.6x10 -4 M

  18. Direct dry transfer of CVD graphene to an optical substrate by in situ photo-polymerization

    Science.gov (United States)

    Kessler, Felipe; Muñoz, Pablo A. R.; Phelan, Ciaran; Romani, Eric C.; Larrudé, Dunieskys R. G.; Freire, Fernando L.; Thoroh de Souza, Eunézio A.; de Matos, Christiano J. S.; Fechine, Guilhermino J. M.

    2018-05-01

    Here, we report on a method that allows graphene produced by chemical vapor deposition (CVD) to be directly transferred to an optically transparent photo resin, by in situ photo-polymerization of the latter, with high efficiency and low contamination. Two photocurable resins, A and B, with different viscosities but essentially the same chemical structure, were used. Raman spectroscopy and surface energy results show that large continuous areas of graphene were transferred with minimal defects to the lower viscosity resin (B), due to the better contact between the resin and graphene. As a proof-of-principle optical experiment, graphene on the polymeric substrate was subjected to high-intensity femtosecond infrared pulses and third-harmonic generation was observed with no noticeable degradation of the sample. A sheet third-order susceptibility χ (3) = 0.71 ×10-28m3V-2 was obtained, matching that of graphene on a glass substrate. These results indicate the suitability of the proposed transfer method, and of the photo resin, for the production of nonlinear photonic components and devices.

  19. Regressed relations for forced convection heat transfer in a direct injection stratified charge rotary engine

    Science.gov (United States)

    Lee, Chi M.; Schock, Harold J.

    1988-01-01

    Currently, the heat transfer equation used in the rotary combustion engine (RCE) simulation model is taken from piston engine studies. These relations have been empirically developed by the experimental input coming from piston engines whose geometry differs considerably from that of the RCE. The objective of this work was to derive equations to estimate heat transfer coefficients in the combustion chamber of an RCE. This was accomplished by making detailed temperature and pressure measurements in a direct injection stratified charge (DISC) RCE under a range of conditions. For each specific measurement point, the local gas velocity was assumed equal to the local rotor tip speed. Local physical properties of the fluids were then calculated. Two types of correlation equations were derived and are described in this paper. The first correlation expresses the Nusselt number as a function of the Prandtl number, Reynolds number, and characteristic temperature ratio; the second correlation expresses the forced convection heat transfer coefficient as a function of fluid temperature, pressure and velocity.

  20. Influence of high range of mass transfer coefficient and convection heat transfer on direct contact membrane distillation performance

    KAUST Repository

    Lee, Jung Gil; Jeong, Sanghyun; Alsaadi, Ahmad Salem; Ghaffour, NorEddine

    2017-01-01

    (>2.1×10−6kg/m2sPa: membranes under development) were simulated using an experimentally validated model at different ranges of convection heat transfer by varying the inlet flow rates and spacer enhancement factor. The effect of mass transfer

  1. Directional loudness in an anechoic sound field, head-related transfer functions, and binaural summation

    DEFF Research Database (Denmark)

    Sivonen, Ville Pekka; Ellermeier, Wolfgang

    2006-01-01

    planes. Matches were obtained via a two-interval, adaptive forced-choice (2AFC) procedure for three center frequencies (0.4, 1 and 5 kHz) and two overall levels (45 and 65 dB SPL). The results showed that loudness is not constant over sound incidence angles, with directional sensitivity varying over......The effect of sound incidence angle on loudness was investigated using real sound sources positioned in an anechoic chamber. Eight normal-hearing listeners produced loudness matches between a frontal reference location and seven sources placed at other directions, both in the horizontal and median...... a range of up to 10 dB, exhibiting considerable frequency dependence, but only minor effects of overall level. The pattern of results varied substantially between subjects, but was largely accounted for by variations in individual head-related transfer functions. Modeling of binaural loudness based...

  2. Demonstration of Lignin-to-Peroxidase Direct Electron Transfer: A TRANSIENT-STATE KINETICS, DIRECTED MUTAGENESIS, EPR, AND NMR STUDY.

    Science.gov (United States)

    Sáez-Jiménez, Verónica; Baratto, Maria Camilla; Pogni, Rebecca; Rencoret, Jorge; Gutiérrez, Ana; Santos, José Ignacio; Martínez, Angel T; Ruiz-Dueñas, Francisco Javier

    2015-09-18

    Versatile peroxidase (VP) is a high redox-potential peroxidase of biotechnological interest that is able to oxidize phenolic and non-phenolic aromatics, Mn(2+), and different dyes. The ability of VP from Pleurotus eryngii to oxidize water-soluble lignins (softwood and hardwood lignosulfonates) is demonstrated here by a combination of directed mutagenesis and spectroscopic techniques, among others. In addition, direct electron transfer between the peroxidase and the lignin macromolecule was kinetically characterized using stopped-flow spectrophotometry. VP variants were used to show that this reaction strongly depends on the presence of a solvent-exposed tryptophan residue (Trp-164). Moreover, the tryptophanyl radical detected by EPR spectroscopy of H2O2-activated VP (being absent from the W164S variant) was identified as catalytically active because it was reduced during lignosulfonate oxidation, resulting in the appearance of a lignin radical. The decrease of lignin fluorescence (excitation at 355 nm/emission at 400 nm) during VP treatment under steady-state conditions was accompanied by a decrease of the lignin (aromatic nuclei and side chains) signals in one-dimensional and two-dimensional NMR spectra, confirming the ligninolytic capabilities of the enzyme. Simultaneously, size-exclusion chromatography showed an increase of the molecular mass of the modified residual lignin, especially for the (low molecular mass) hardwood lignosulfonate, revealing that the oxidation products tend to recondense during the VP treatment. Finally, mutagenesis of selected residues neighboring Trp-164 resulted in improved apparent second-order rate constants for lignosulfonate reactions, revealing that changes in its protein environment (modifying the net negative charge and/or substrate accessibility/binding) can modulate the reactivity of the catalytic tryptophan. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  3. Direct numerical simulation of fluid-particle heat transfer in fixed random arrays of non-spherical particles

    NARCIS (Netherlands)

    Tavassoli Estahbanati, H.; Peters, E.A.J.F.; Kuipers, J.A.M.

    2015-01-01

    Direct numerical simulations are conducted to characterize the fluid-particle heat transfer coefficient in fixed random arrays of non-spherical particles. The objective of this study is to examine the applicability of well-known heat transfer correlations, that are proposed for spherical particles,

  4. Rabbit IgG directed to a synthetic C-terminal peptide of the major grass pollen allergen Lol p I inhibits human basophil histamine release induced by natural Lol p I.

    Science.gov (United States)

    van Ree, R; Aalberse, R C

    1995-03-01

    The potential role of allergen-specific IgG antibodies as 'blocking' antibodies in allergen-induced human basophil histamine release was investigated. This was studied in a model with the major grass pollen allergen Lol p I and polyclonal rabbit antisera directed against this allergen and against a synthetic peptide of its C terminus. When allergen and antibodies were allowed to preincubate, Lol p I induced histamine release was inhibited up to 85% by the antiserum against Lol p I. By omitting preincubation, and thereby more closely mimicking an in vivo situation, up to 55% inhibition was realized. This indicates that allergen-specific IgG can act as 'blocking' antibody without preincubation. Immunization of rabbits with a synthetic C-terminal peptide of Lol p I resulted in antibodies reactive with natural Lol p I. Despite their 100-fold lower avidity for Lol p I (as compared with antinatural Lol p I), these antibodies had the capacity to inhibit Lol p I induced histamine release for > 90% (up to 50% without preincubation). This indicates that it is possible to block histamine release induced by a major allergen with low-avidity IgG antibodies directed against a minor proportion of the allergen (25 amino acids). IgE antibodies from the donors studied were unreactive with this synthetic peptide, indicating that for blocking activity identical epitope specificity of IgE and IgG is not essential. This opens interesting perspectives for application of synthetic peptides in immunotherapy, distinct from their effects on T cell reactivity.

  5. Increasing Juniperus virginiana L. pollen in the Tulsa atmosphere: long-term trends, variability, and influence of meteorological conditions

    Science.gov (United States)

    Flonard, Michaela; Lo, Esther; Levetin, Estelle

    2018-02-01

    In the Tulsa area, the Cupressaceae is largely represented by eastern red cedar ( Juniperus virginiana L.). The encroachment of this species into the grasslands of Oklahoma has been well documented, and it is believed this trend will continue. The pollen is known to be allergenic and is a major component of the Tulsa atmosphere in February and March. This study examined airborne Cupressaceae pollen data from 1987 to 2016 to determine long-term trends, pollen seasonal variability, and influence of meteorological variables on airborne pollen concentrations. Pollen was collected through means of a Burkard sampler and analyzed with microscopy. Daily pollen concentrations and yearly pollen metrics showed a high degree of variability. In addition, there were significant increases over time in the seasonal pollen index and in peak concentrations. These increases parallel the increasing population of J. virginiana in the region. Pollen data were split into pre- and post-peak categories for statistical analyses, which revealed significant differences in correlations of the two datasets when analyzed with meteorological conditions. While temperature and dew point, among others were significant in both datasets, other factors, like relative humidity, were significant only in one dataset. Analyses using wind direction showed that southerly and southwestern winds contributed to increased pollen concentrations. This study confirms that J. virginiana pollen has become an increasing risk for individuals sensitive to this pollen and emphasizes the need for long-term aerobiological monitoring in other areas.

  6. Comparison of modern pollen distribution between the northern and southern parts of the South China Sea.

    Science.gov (United States)

    Luo, Chuanxiu; Chen, Muhong; Xiang, Rong; Liu, Jianguo; Zhang, Lanlan; Lu, Jun

    2015-04-01

    The authors conducted a palynological analysis based on different number of air pollen samples for the northern and southern parts of the South China Sea, respectively, in order to give a reference to reconstruct the paleoclimate of the area. (1) Fifteen air pollen samples were collected from the northern part of the South China Sea from August to September 2011, and 13 air pollen samples were collected from the southern part of the South China Sea in December 2011. The pollen types were more abundant in the north than in the south. The total pollen number and concentration in the north was 10 times more than that in the south, which may be because of the sampling season. Airborne pollen types and concentrations have a close relationship with wind direction and distance from the sampling point to the continent. (2) Seventy-four samples were collected from surface sediments in the northern part of the South China Sea in the autumn. Thirty-three samples were collected from surface sediments in the southern part of the South China Sea in the winter. Pollen concentrations in the north were nearly 10 times higher than that in the south. This is because trilete spores are transported by rivers from Hainan Island to the sea and also by the summer monsoon-forced marine current. (3) Ten air pollen samples and 10 surface sediments samples were selected for comparison. The pollen and spores in the air were mainly herbaceous and woody pollen, excluding fern spores, having seasonal pollen characteristics. Pollen in the surface sediments were mainly trilete, Pinus, and herbaceous, and may also show a combination of annual pollen characteristics.

  7. Mycobiota and mycotoxins in bee pollen collected from different areas of Slovakia.

    Science.gov (United States)

    Kačániová, Miroslava; Juráček, Miroslav; Chlebo, Róbert; Kňazovická, Vladimíra; Kadasi-Horáková, Miriam; Kunová, Simona; Lejková, Jadža; Haščík, Peter; Mareček, Ján; Simko, Milan

    2011-01-01

    Contamination by microscopic fungi and mycotoxins in different bee pollen samples, which were stored under three different ways of storing as freezing, drying and UV radiation, was investigated. During spring 2009, 45 samples of bee-collected pollen were gathered from beekeepers who placed their bee colonies on monocultures of sunflower, rape and poppy fields within their flying distance. Bee pollen was collected from bees' legs by special devices placed at the entrance to hives. Samples were examined for the concentration and identification of microscopic fungi able to grow on Malt and Czapek-Dox agar and mycotoxins content [deoxynivalenol (DON), T-2 toxin (T-2), zearalenone (ZON) and total aflatoxins (AFL), fumonisins (FUM), ochratoxins (OTA)] by direct competitive enzyme-linked immunosorbent assays (ELISA). The total number of microscopic fungi in this study ranged from 2.98 ± 0.02 in frozen sunflower bee pollen to 4.06 ± 0.10 log cfu.g(-1) in sunflower bee pollen after UV radiation. In this study, 449 isolates belonging to 21 fungal species representing 9 genera were found in 45 samples of bee pollen. The total isolates were detected in frozen poppy pollen 29, rape pollen 40, sunflower pollen 80, in dried poppy pollen 12, rape pollen 36, sunflower 78, in poppy pollen after UV radiation treatment 54, rape 59 and sunflower 58. The most frequent isolates of microscopic fungi found in bee pollen samples of all prevalent species were Mucor mucedo (49 isolates), Alternaria alternata (40 isolates), Mucor hiemalis (40 isolates), Aspergillus fumigatus (33 isolates) and Cladosporium cladosporioides (31 isolates). The most frequently found isolates were detected in sunflower bee pollen frozen (80 isolates) and the lowest number of isolates was observed in poppy bee pollen dried (12 isolates). The most prevalent mycotoxin of poppy bee pollen was ZON (361.55 ± 0.26 μg.kg(-1)), in rape bee pollen T-2 toxin (265.40 ± 0.18 μg.kg(-1)) and in sunflower bee pollen T-2 toxin

  8. Quantitative radioautographic determination of brain tyrosine hydroxylase after direct transfer into nitro-cellulose and immunochemical detection

    International Nuclear Information System (INIS)

    Weissmann, D.; Labatut, R.; Gillon, J.Y.

    1988-01-01

    An improved quantitative immuno chemical determination of tyrosine hydroxylase brain concentrations was designed by using direct transfer into nitro-cellulose from 20 μm thick brain sections followed by immuno-detection and quantitative radioautography [fr

  9. Pollen rain and pollen representation across a forest-páramo ecotone in northern Ecuador

    NARCIS (Netherlands)

    Moscol Olivera, M.; Duivenvoorden, J.F.; Hooghiemstra, H.

    2009-01-01

    Modern pollen spectra were studied in forest and páramo vegetation from the Guandera area, northern Ecuador. Pollen representation was estimated by comparing the presence of plant taxa from a recent vegetation survey with the pollen spectra in moss polsters and pollen traps. In total, 73 pollen taxa

  10. CHARACTERIZATION OF THE MAIZE POLLEN TRANSCRIPTOME

    Science.gov (United States)

    Pollen is a primary vehicle for transgene flow from engineered plants to their non-transgenic, native or weedy relatives. Hence, gene flow will be affected by pollen fitness (e.g., how well a particular pollen grain can outcompete other pollen present on the stigma and complete ...

  11. Transfer

    DEFF Research Database (Denmark)

    Wahlgren, Bjarne; Aarkrog, Vibe

    Bogen er den første samlede indføring i transfer på dansk. Transfer kan anvendes som praksis-filosofikum. Den giver en systematisk indsigt til den studerende, der spørger: Hvordan kan teoretisk viden bruges til at reflektere over handlinger i situationer, der passer til min fremtidige arbejdsplads?...

  12. A Taxonomic Reduced-Space Pollen Model for Paleoclimate Reconstruction

    Science.gov (United States)

    Wahl, E. R.; Schoelzel, C.

    2010-12-01

    Paleoenvironmental reconstruction from fossil pollen often attempts to take advantage of the rich taxonomic diversity in such data. Here, a taxonomically "reduced-space" reconstruction model is explored that would be parsimonious in introducing parameters needing to be estimated within a Bayesian Hierarchical Modeling context. This work involves a refinement of the traditional pollen ratio method. This method is useful when one (or a few) dominant pollen type(s) in a region have a strong positive correlation with a climate variable of interest and another (or a few) dominant pollen type(s) have a strong negative correlation. When, e.g., counts of pollen taxa a and b (r >0) are combined with pollen types c and d (r logistic generalized linear model (GLM). The GLM can readily model this relationship in the forward form, pollen = g(climate), which is more physically realistic than inverse models often used in paleoclimate reconstruction [climate = f(pollen)]. The specification of the model is: rnum Bin(n,p), where E(r|T) = p = exp(η)/[1+exp(η)], and η = α + β(T); r is the pollen ratio formed as above, rnum is the ratio numerator, n is the ratio denominator (i.e., the sum of pollen counts), the denominator-specific count is (n - rnum), and T is the temperature at each site corresponding to a specific value of r. Ecological and empirical screening identified the model (Spruce+Birch) / (Spruce+Birch+Oak+Hickory) for use in temperate eastern N. America. α and β were estimated using both "traditional" and Bayesian GLM algorithms (in R). Although it includes only four pollen types, the ratio model yields more explained variation ( 80%) in the pollen-temperature relationship of the study region than a 64-taxon modern analog technique (MAT). Thus, the new pollen ratio method represents an information-rich, reduced space data model that can be efficiently employed in a BHM framework. The ratio model can directly reconstruct past temperature by solving the GLM equations

  13. Inverting Steric Effects: Using "Attractive" Noncovalent Interactions To Direct Silver-Catalyzed Nitrene Transfer.

    Science.gov (United States)

    Huang, Minxue; Yang, Tzuhsiung; Paretsky, Jonathan D; Berry, John F; Schomaker, Jennifer M

    2017-12-06

    Nitrene transfer (NT) reactions represent powerful and direct methods to convert C-H bonds into amine groups that are prevalent in many commodity chemicals and pharmaceuticals. The importance of the C-N bond has stimulated the development of numerous transition-metal complexes to effect chemo-, regio-, and diastereoselective NT. An ongoing challenge is to understand how subtle interactions between catalyst and substrate influence the site-selectivity of the C-H amination event. In this work, we explore the underlying reasons why Ag(tpa)OTf (tpa = tris(pyridylmethyl)amine) prefers to activate α-conjugated C-H bonds over 3° alkyl C(sp 3 )-H bonds and apply these insights to reaction optimization and catalyst design. Experimental results suggest possible roles of noncovalent interactions (NCIs) in directing the NT; computational studies support the involvement of π···π and Ag···π interactions between catalyst and substrate, primarily by lowering the energy of the directed transition state and reaction conformers. A simple Hess's law relationship can be employed to predict selectivities for new substrates containing competing NCIs. The insights presented herein are poised to inspire the design of other catalyst-controlled C-H functionalization reactions.

  14. Design of triads for probing the direct through space energy transfers in closely spaced assemblies.

    Science.gov (United States)

    Camus, Jean-Michel; Aly, Shawkat M; Fortin, Daniel; Guilard, Roger; Harvey, Pierre D

    2013-08-05

    Using a selective stepwise Suzuki cross-coupling reaction, two trimers built on three different chromophores were prepared. These trimers exhibit a D(^)A1-A2 structure where the donor D (octa-β-alkyl zinc(II)porphyrin either as diethylhexamethyl, 10a, or tetraethyltetramethyl, 10b, derivatives) through space transfers the S1 energy to two different acceptors, di(4-ethylbenzene) zinc(II)porphyrin (A1; acceptor 1) placed cofacial with D, and the corresponding free base (A2; acceptor 2), which is meso-meso-linked with A1. This structure design allows for the possibility of comparing two series of assemblies, 9a,b (D(^)A1) with 10a,b (D(^)Â1-A2), for the evaluation of the S1 energy transfer for the global process D*→A2 in the trimers. From the comparison of the decays of the fluorescence of D, the rates for through space energy transfer, kET for 10a,b (kET ≈ 6.4 × 10(9) (10a), 5.9 × 10(9) s(-1) (10b)), and those for the corresponding cofacial D(^)A1 systems, 9a,b, (kET ≈ 5.0 × 10(9) (9a), 4.7 × 10(9) s(-1) (9b)), provide an estimate for kET for the direct through space D*→A2 process (i.e., kET(D(^)A1-A2) - kET(D(^)A1) = kET(D*→A2) ∼ 1 × 10(9) s(-1)). This channel of relaxation represents ∼15% of kET for D*→A1.

  15. Personal exposure to grass pollen: relating inhaled dose to background concentration

    DEFF Research Database (Denmark)

    Peel, Robert George; Hertel, Ole; Smith, Matt

    2013-01-01

    Background: Very few studies on human exposure to allergenic pollen have been conducted using direct methods, with background concentrations measured at city center monitoring stations typically taken as a proxy for exposure despite the inhomogeneous nature of atmospheric pollen concentrations. A...

  16. The influence of pollen γ-irradiation of the growth and development of plants

    International Nuclear Information System (INIS)

    Andrejchenko, S.V.; Grodzinskij, D.M.

    1986-01-01

    A study was made on the influence of pollen gamma irradiation on induction of phenotypic mutation in F 1 hybrid petunia. Some dose regularities characterizing the rate of growth and development of daughter plants were revealed. It was shown that seed formation and embryogenesis depend directly on the degree of pollen gamma irradiation damage

  17. Direct absorption and transfer of cesium 137 in a simplified fresh water supply line

    International Nuclear Information System (INIS)

    Foulquier, L.; Grauby, A.; Lambrechts, A.

    1977-01-01

    Experimentally the transfer of Cesium 137 through the supply line: Daphnia Magna Straus→Lebistes Reticulatus Peters→Anguilla Anguilla L. starting from water at 50μCi/l is studied. In the direct transfer water→organisms, the three links used have a concentration factor comprised between 2 and 4. The organisms retain a maximum of 0,3% of the water's radioactivity. The muscular mass of the eel represents 60% of the animal's total activity. The biological period is close to 400 days indicating that the fixed Cesium is strongly retained. Through the absorption of a contaminated meal, the Lebists, after two days, retain 67% of the activities of the Daphnies and the Eels, after seven days, 39% of the activity of the Guppys. At the end of the experiment, the Eels contaminated by food 3.500. It takes 63 meals for the level of contamination due to food to equal that due to water. The concentration factors measured in situ are always distinctly higher than those obtained in the laboratory. The experiment proves the possibilities of concentration through the food supply line [fr

  18. The FluxCompensator: Making Radiative Transfer Models of Hydrodynamical Simulations Directly Comparable to Real Observations

    Energy Technology Data Exchange (ETDEWEB)

    Koepferl, Christine M.; Robitaille, Thomas P., E-mail: koepferl@usm.lmu.de [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany)

    2017-11-01

    When modeling astronomical objects throughout the universe, it is important to correctly treat the limitations of the data, for instance finite resolution and sensitivity. In order to simulate these effects, and to make radiative transfer models directly comparable to real observations, we have developed an open-source Python package called the FluxCompensator that enables the post-processing of the output of 3D Monte Carlo radiative transfer codes, such as Hyperion. With the FluxCompensator, realistic synthetic observations can be generated by modeling the effects of convolution with arbitrary point-spread functions, transmission curves, finite pixel resolution, noise, and reddening. Pipelines can be applied to compute synthetic observations that simulate observatories, such as the Spitzer Space Telescope or the Herschel Space Observatory . Additionally, this tool can read in existing observations (e.g., FITS format) and use the same settings for the synthetic observations. In this paper, we describe the package as well as present examples of such synthetic observations.

  19. The FluxCompensator: Making Radiative Transfer Models of Hydrodynamical Simulations Directly Comparable to Real Observations

    Science.gov (United States)

    Koepferl, Christine M.; Robitaille, Thomas P.

    2017-11-01

    When modeling astronomical objects throughout the universe, it is important to correctly treat the limitations of the data, for instance finite resolution and sensitivity. In order to simulate these effects, and to make radiative transfer models directly comparable to real observations, we have developed an open-source Python package called the FluxCompensator that enables the post-processing of the output of 3D Monte Carlo radiative transfer codes, such as Hyperion. With the FluxCompensator, realistic synthetic observations can be generated by modeling the effects of convolution with arbitrary point-spread functions, transmission curves, finite pixel resolution, noise, and reddening. Pipelines can be applied to compute synthetic observations that simulate observatories, such as the Spitzer Space Telescope or the Herschel Space Observatory. Additionally, this tool can read in existing observations (e.g., FITS format) and use the same settings for the synthetic observations. In this paper, we describe the package as well as present examples of such synthetic observations.

  20. Reliability analysis of an LCL tuned track segmented bi-directional inductive power transfer system

    DEFF Research Database (Denmark)

    Asif Iqbal, S. M.; Madawala, U. K.; Thrimawithana, D. J.

    2013-01-01

    Bi-directional Inductive Power Transfer (BDIPT) technique is suitable for renewable energy based applications such as electric vehicles (EVs), for the implementation of vehicle-to-grid (V2G) systems. Recently, more efforts have been made by researchers to improve both efficiency and reliability...... of renewable energy systems to further enhance their economical sustainability. This paper presents a comparative reliability study between a typical BDIPT system and an individually controlled segmented BDIPT system. Steady state thermal simulation results are provided for different output power levels...... for a 1.5 kW BDIPT system in a MATLAB/Simulink environment. Reliability parameters such as failure rate and mean time between failures (MTBF) are compared between the two systems. A nonlinear programming (NP) model is developed for optimizing charging schedule for a stationery EV. A case study of EV...

  1. Ab initio study of charge transfer between lithium and aromatic hydrocarbons. Can the results be directly transferred to the lithium-graphene interaction?

    Science.gov (United States)

    Sadlej-Sosnowska, N

    2014-08-28

    We have used electronic density calculations to study neutral complexes of Li with aromatic hydrocarbons. The charge transferred between a Li atom and benzene, coronene, circumcoronene, and circumcircumcoronene has been studied by ab initio methods (at the HF and MP2 level). Toward this aim, the method of integrating electron density in two cuboid fragments of space was applied. One of the fragments was constructed so that it enclosed the bulk of the electron density of lithium; the second, the bulk of the electron density of hydrocarbon. It was found that for each complex two conformations were identified: the most stable with a greater vertical Li-hydrocarbon distance, on the order of 2.5 Å, and another of higher energy with a corresponding distance less than 2 Å. In all cases the transfer of a fractional number, 0.1-0.3 electrons, between Li and hydrocarbon was found; however, the direction of the transfer was not the same in all complexes investigated. The structures of complexes of the first configuration could be represented as Li(σ-)···AH(σ+), whereas the opposite direction of charge transfer was found for complexes of the second configuration, with higher energy. The directions of the dipole moments in the complexes supported these conclusions because they directly measure the redistribution of electron density in a complex with respect to substrates.

  2. In Situ Blotting : A Novel Method for Direct Transfer of Native Proteins from Sectioned Tissue to Blotting Membrane

    NARCIS (Netherlands)

    Okabe, Masashi; Nyakas, Csaba; Buwalda, Bauke; Luiten, Paul G.M.

    1993-01-01

    We describe a novel technique for direct transfer of native proteins from unfixed frozen tissue sections to an immobilizing matrix, e.g., nitrocellulose, polyvinyliden difluoride, or positively charged nylon membranes. Proteins are directly blotted onto the membrane, providing optimal accessibility

  3. Effect of gamma rays doses on pollen germination, polysiphony and pollen tube elongation in Pinus patula Schiede et Deppe

    International Nuclear Information System (INIS)

    Katiyar, S.R.; Chauhan, Y.S.

    1987-01-01

    The present study aimed to study the effects of gamma radiation ( 60 Co) on pollen germination and pollen tube elongation in Pinus patula. Pollen germination and pollen tube elongation are stimulated by low doses of radiation. Although higher doses of radiation inhibit the germination of pollen, pollen tube elongation remains unaffected. Thus in Pinus patula pollen tube elongation is less radiosensitive than pollen germination. Compared to control pollen, irradiated pollen produced more number of long pollen tubes. Therefore pollen tube size can be improved using low doses of radiation. (author). 15 refs., 5 figs., 2 tables

  4. The Metabolic Basis of Pollen Thermo-Tolerance: Perspectives for Breeding

    Directory of Open Access Journals (Sweden)

    Marine J. Paupière

    2014-09-01

    Full Text Available Crop production is highly sensitive to elevated temperatures. A rise of a few degrees above the optimum growing temperature can lead to a dramatic yield loss. A predicted increase of 1–3 degrees in the twenty first century urges breeders to develop thermo-tolerant crops which are tolerant to high temperatures. Breeding for thermo-tolerance is a challenge due to the low heritability of this trait. A better understanding of heat stress tolerance and the development of reliable methods to phenotype thermo-tolerance are key factors for a successful breeding approach. Plant reproduction is the most temperature-sensitive process in the plant life cycle. More precisely, pollen quality is strongly affected by heat stress conditions. High temperature leads to a decrease of pollen viability which is directly correlated with a loss of fruit production. The reduction in pollen viability is associated with changes in the level and composition of several (groups of metabolites, which play an important role in pollen development, for example by contributing to pollen nutrition or by providing protection to environmental stresses. This review aims to underline the importance of maintaining metabolite homeostasis during pollen development, in order to produce mature and fertile pollen under high temperature. The review will give an overview of the current state of the art on the role of various pollen metabolites in pollen homeostasis and thermo-tolerance. Their possible use as metabolic markers to assist breeding programs for plant thermo-tolerance will be discussed.

  5. The metabolic basis of pollen thermo-tolerance: perspectives for breeding.

    Science.gov (United States)

    Paupière, Marine J; van Heusden, Adriaan W; Bovy, Arnaud G

    2014-09-30

    Crop production is highly sensitive to elevated temperatures. A rise of a few degrees above the optimum growing temperature can lead to a dramatic yield loss. A predicted increase of 1-3 degrees in the twenty first century urges breeders to develop thermo-tolerant crops which are tolerant to high temperatures. Breeding for thermo-tolerance is a challenge due to the low heritability of this trait. A better understanding of heat stress tolerance and the development of reliable methods to phenotype thermo-tolerance are key factors for a successful breeding approach. Plant reproduction is the most temperature-sensitive process in the plant life cycle. More precisely, pollen quality is strongly affected by heat stress conditions. High temperature leads to a decrease of pollen viability which is directly correlated with a loss of fruit production. The reduction in pollen viability is associated with changes in the level and composition of several (groups of) metabolites, which play an important role in pollen development, for example by contributing to pollen nutrition or by providing protection to environmental stresses. This review aims to underline the importance of maintaining metabolite homeostasis during pollen development, in order to produce mature and fertile pollen under high temperature. The review will give an overview of the current state of the art on the role of various pollen metabolites in pollen homeostasis and thermo-tolerance. Their possible use as metabolic markers to assist breeding programs for plant thermo-tolerance will be discussed.

  6. Effects of CO₂ on Acer negundo pollen fertility, protein content, allergenic properties, and carbohydrates.

    Science.gov (United States)

    Silva, M; Ribeiro, H; Abreu, I; Cruz, A; Esteves da Silva, J C G

    2015-05-01

    Atmospheric gaseous pollutants can induce qualitative and quantitative changes in airborne pollen characteristics. In this work, it was investigated the effects of carbon dioxide (CO2) on Acer negundo pollen fertility, protein content, allergenic properties, and carbohydrates. Pollen was collected directly from the anthers and in vitro exposed to three CO2 levels (500, 1000, and 3000 ppm) for 6 and 24 h in an environmental chamber. Pollen fertility was determined using viability and germination assays, total soluble protein was determined with Coomassie Protein Assay Reagent, and the antigenic and allergenic properties were investigated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunological techniques using patients' sera. Also, pollen fructose, sucrose, and glucose values were determined. Carbon dioxide exposure affected negatively pollen fertility, total soluble protein content, and fructose content. The patient sera revealed increased IgE reactivity to proteins of A. negundo pollen exposed to increasing levels of the pollutant. No changes were detected in the SDS-PAGE protein profiles and in sucrose and glucose levels. Our results indicate that increase in atmospheric CO2 concentrations can have a negative influence of some features of A. negundo airborne pollen that can influence the reproductive processes as well as respiratory pollen allergies in the future.

  7. Direct heat transfer considerations for improving energy efficiency in pulp and paper Kraft mills

    Energy Technology Data Exchange (ETDEWEB)

    Savulescu, Luciana Elena; Alva-Argaez, Alberto [Natural Resources (Canada)

    2008-10-15

    The success of any process improvement study depends on the quality of the available data and the way in which the plant-specific characteristics are incorporated in the applied conceptual models; in the context of process integration studies these issues are directly related to the rules followed during the data extraction stage. Improving energy efficiency in a pulp and paper Kraft mill requires the identification of the most promising heat recovery network retrofit projects. In a retrofit analysis using pinch technology/process integration methods, only the process streams associated to the existing heat exchangers and some outlet streams (such as wastewater/effluent streams and vents) with high potential for heat recovery are usually included, while the energy exchanged through non-isothermal stream mixing (NIM) or direct heat transfer (DHT) is often assumed fixed and is not considered in the analysis. Relaxing this assumption requires extracting more data to represent the DHT design configuration that exists in the plant. However, different data extraction options can be considered to represent the DHT configuration depending on the associated process/operation constraints. This work describes a systematic procedure to extract and analyse the impacts of DHT on the overall energy efficiency of a Kraft process with a specific focus on mixing along the pulp line and in water tanks. (author)

  8. Direct heat transfer considerations for improving energy efficiency in pulp and paper Kraft mills

    International Nuclear Information System (INIS)

    Savulescu, Luciana Elena; Alva-Argaez, Alberto

    2008-01-01

    The success of any process improvement study depends on the quality of the available data and the way in which the plant-specific characteristics are incorporated in the applied conceptual models; in the context of process integration studies these issues are directly related to the rules followed during the data extraction stage. Improving energy efficiency in a pulp and paper Kraft mill requires the identification of the most promising heat recovery network retrofit projects. In a retrofit analysis using pinch technology/process integration methods, only the process streams associated to the existing heat exchangers and some outlet streams (such as wastewater/effluent streams and vents) with high potential for heat recovery are usually included, while the energy exchanged through non-isothermal stream mixing (NIM) or direct heat transfer (DHT) is often assumed fixed and is not considered in the analysis. Relaxing this assumption requires extracting more data to represent the DHT design configuration that exists in the plant. However, different data extraction options can be considered to represent the DHT configuration depending on the associated process/operation constraints. This work describes a systematic procedure to extract and analyse the impacts of DHT on the overall energy efficiency of a Kraft process with a specific focus on mixing along the pulp line and in water tanks

  9. Role and Potential of Direct Interspecies Electron Transfer in Anaerobic Digestion

    Directory of Open Access Journals (Sweden)

    Gahyun Baek

    2018-01-01

    Full Text Available Anaerobic digestion (AD is an effective biological treatment for stabilizing organic compounds in waste/wastewater and in simultaneously producing biogas. However, it is often limited by the slow reaction rates of different microorganisms’ syntrophic biological metabolisms. Stable and fast interspecies electron transfer (IET between volatile fatty acid-oxidizing bacteria and hydrogenotrophic methanogens is crucial for efficient methanogenesis. In this syntrophic interaction, electrons are exchanged via redox mediators such as hydrogen and formate. Recently, direct IET (DIET has been revealed as an important IET route for AD. Microorganisms undergoing DIET form interspecies electrical connections via membrane-associated cytochromes and conductive pili; thus, redox mediators are not required for electron exchange. This indicates that DIET is more thermodynamically favorable than indirect IET. Recent studies have shown that conductive materials (e.g., iron oxides, activated carbon, biochar, and carbon fibers can mediate direct electrical connections for DIET. Microorganisms attach to conductive materials’ surfaces or vice versa according to particle size, and form conductive biofilms or aggregates. Different conductive materials promote DIET and improve AD performance in digesters treating different feedstocks, potentially suggesting a new approach to enhancing AD performance. This review discusses the role and potential of DIET in methanogenic systems, especially with conductive materials for promoting DIET.

  10. Workshop on Direct Contact Heat Transfer at the Solar Energy Research Institute

    CERN Document Server

    Boehm, R

    1988-01-01

    to increase the use of direct contact processes, the National Science Foundation sup­ ported a workshop on direct contact heat transfer at the Solar Energy Research Insti­ tute in the summer of 1985. We served as organizers for this workshop, which em­ phasized an area of thermal engineering that, in our opinion, has great promise for the future, but has not yet reached the point of wide-spread commercial application. Hence, a summary of the state of knowledge at this point is timely. The workshop had a dual objective: 1. To summarize the current state of knowledge in such a form that industrial practi­ tioners can make use of the available information. 2. To indicate the research and development needed to advance the state-of-the-art, indicating not only what kind of research is needed, but also the industrial poten­ tial that could be realized if the information to be obtained through the proposed research activities were available.

  11. Pollen Forecast and Dispersion Modelling

    Science.gov (United States)

    Costantini, Monica; Di Giuseppe, Fabio; Medaglia, Carlo Maria; Travaglini, Alessandro; Tocci, Raffaella; Brighetti, M. Antonia; Petitta, Marcello

    2014-05-01

    The aim of this study is monitoring, mapping and forecast of pollen distribution for the city of Rome using in-situ measurements of 10 species of common allergenic pollens and measurements of PM10. The production of daily concentration maps, associated to a mobile phone app, are innovative compared to existing dedicated services to people who suffer from respiratory allergies. The dispersal pollen is one of the most well-known causes of allergic disease that is manifested by disorders of the respiratory functions. Allergies are the third leading cause of chronic disease and it is estimated that tens millions of people in Italy suffer from it. Recent works reveal that during the last few years there was a progressive increase of affected subjects, especially in urban areas. This situation may depend: on the ability to transport of pollutants, on the ability to react between pollutants and pollen and from a combination of other irritants, existing in densely populated and polluted urban areas. The methodology used to produce maps is based on in-situ measurements time series relative to 2012, obtained from networks of air quality and pollen stations in the metropolitan area of Rome. The monitoring station aerobiological of University of Rome "Tor Vergata" is located at the Department of Biology. The instrument used to pollen monitoring is a volumetric sampler type Hirst (Hirst 1952), Model 2000 VPPS Lanzoni; the data acquisition is carried out as reported in Standard UNI 11008:2004 - "Qualità dell'aria - Metodo di campionamento e conteggio dei granuli pollinici e delle spore fungine aerodisperse" - the protocol that describes the procedure for measuring of the concentration of pollen grains and fungal spores dispersed into the atmosphere, and reported in the "Manuale di gestione e qualità della R.I.M.A" (Travaglini et. al. 2009). All 10 allergenic pollen are monitored since 1996. At Tor Vergata university is also operating a meteorological station (SP2000, CAE

  12. Distinct chromatin environment associated with phosphorylated H3S10 histone during pollen mitosis I in orchids.

    Science.gov (United States)

    Sharma, Santosh Kumar; Yamamoto, Maki; Mukai, Yasuhiko

    2017-01-01

    Pollen developmental pathway in plants involving synchronized transferal of cellular divisions from meiosis (microsporogenesis) to mitosis (pollen mitosis I/II) eventually offers a unique "meiosis-mitosis shift" at pollen mitosis I. Since the cell type (haploid microspore) and fate of pollen mitosis I differ from typical mitosis (in meristem cells), it is immensely important to analyze the chromosomal distribution of phosphorylated H3S10 histone during atypical pollen mitosis I to comprehend the role of histone phosphorylation in pollen development. We investigated the chromosomal phosphorylation of H3S10 histone during pollen mitosis I in orchids using immunostaining technique. The chromosomal distribution of H3S10ph during pollen mitosis I revealed differential pattern than that of typical mitosis in plants, however, eventually following the similar trends of mitosis in animals where H3S10 phosphorylation begins in the pericentromeric regions first, later extending to the whole chromosomes, and finally declining at anaphase/early cytokinesis (differentiation of vegetative and generative cells). The study suggests that the chromosomal distribution of H3S10ph during cell division is not universal and can be altered between different cell types encoded for diverse cellular processes. During pollen development, phosphorylation of histone might play a critical role in chromosome condensation events throughout pollen mitosis I in plants.

  13. Fencing network direct memory access data transfers in a parallel active messaging interface of a parallel computer

    Science.gov (United States)

    Blocksome, Michael A.; Mamidala, Amith R.

    2015-07-07

    Fencing direct memory access (`DMA`) data transfers in a parallel active messaging interface (`PAMI`) of a parallel computer, the PAMI including data communications endpoints, each endpoint including specifications of a client, a context, and a task, the endpoints coupled for data communications through the PAMI and through DMA controllers operatively coupled to a deterministic data communications network through which the DMA controllers deliver data communications deterministically, including initiating execution through the PAMI of an ordered sequence of active DMA instructions for DMA data transfers between two endpoints, effecting deterministic DMA data transfers through a DMA controller and the deterministic data communications network; and executing through the PAMI, with no FENCE accounting for DMA data transfers, an active FENCE instruction, the FENCE instruction completing execution only after completion of all DMA instructions initiated prior to execution of the FENCE instruction for DMA data transfers between the two endpoints.

  14. Convective heat transfer measurements in a vapour-liquid-liquid three-phase direct contact heat exchanger

    Science.gov (United States)

    Mahood, Hameed B.; Campbell, A. N.; Baqir, Ali Sh.; Sharif, A. O.; Thorpe, R. B.

    2017-12-01

    Energy usage is increasing around the world due to the continued development of technology, and population growth. Solar energy is a promising low-grade energy resource that can be harvested and utilised in different applications, such solar heater systems, which are used in both domestic and industrial settings. However, the implementation of an efficient energy conversion system or heat exchanger would enhance such low-grade energy processes. The direct contact heat exchanger could be the right choice due to its ability to efficiently transfer significant amounts of heat, simple design, and low cost. In this work, the heat transfer associated with the direct contact condensation of pentane vapour bubbles in a three-phase direct contact condenser is investigated experimentally. Such a condenser could be used in a cycle with a solar water heater and heat recovery systems. The experiments on the steady state operation of the three-phase direct contact condenser were carried out using a short Perspex tube of 70 cm in total height and an internal diameter of 4 cm. Only a height of 48 cm was active as the direct contact condenser. Pentane vapour, (the dispersed phase) with three different initial temperatures (40° C, 43.5° C and 47.5° C) was directly contacted with water (the continuous phase) at 19° C. The experimental results showed that the total heat transfer rate per unit volume along the direct contact condenser gradually decreased upon moving higher up the condenser. Additionally, the heat transfer rate increases with increasing mass flow rate ratio, but no significant effect on the heat transfer rate of varying the initial temperature of the dispersed phase was seen. Furthermore, both the outlet temperature of the continuous phase and the void fraction were positively correlated with the total heat transfer rate per unit volume, with no considerable effect of the initial temperature difference between the dispersed and continuous phases.

  15. Convective heat transfer measurements in a vapour-liquid-liquid three-phase direct contact heat exchanger

    Science.gov (United States)

    Mahood, Hameed B.; Campbell, A. N.; Baqir, Ali Sh.; Sharif, A. O.; Thorpe, R. B.

    2018-06-01

    Energy usage is increasing around the world due to the continued development of technology, and population growth. Solar energy is a promising low-grade energy resource that can be harvested and utilised in different applications, such solar heater systems, which are used in both domestic and industrial settings. However, the implementation of an efficient energy conversion system or heat exchanger would enhance such low-grade energy processes. The direct contact heat exchanger could be the right choice due to its ability to efficiently transfer significant amounts of heat, simple design, and low cost. In this work, the heat transfer associated with the direct contact condensation of pentane vapour bubbles in a three-phase direct contact condenser is investigated experimentally. Such a condenser could be used in a cycle with a solar water heater and heat recovery systems. The experiments on the steady state operation of the three-phase direct contact condenser were carried out using a short Perspex tube of 70 cm in total height and an internal diameter of 4 cm. Only a height of 48 cm was active as the direct contact condenser. Pentane vapour, (the dispersed phase) with three different initial temperatures (40° C, 43.5° C and 47.5° C) was directly contacted with water (the continuous phase) at 19° C. The experimental results showed that the total heat transfer rate per unit volume along the direct contact condenser gradually decreased upon moving higher up the condenser. Additionally, the heat transfer rate increases with increasing mass flow rate ratio, but no significant effect on the heat transfer rate of varying the initial temperature of the dispersed phase was seen. Furthermore, both the outlet temperature of the continuous phase and the void fraction were positively correlated with the total heat transfer rate per unit volume, with no considerable effect of the initial temperature difference between the dispersed and continuous phases.

  16. Direct observation of the ultrafast electron transfer process in a polymer/fullerene blend

    NARCIS (Netherlands)

    Cerullo, G.; Lanzani, G.; Silvestri, S. De; Brabec, Ch.J.; Zerza, G.; Sariciftci, N.S.; Hummelen, J.C.

    2000-01-01

    Photoinduced electron transfer in organic molecules is an extensively investigated topic both because of fundamental interest in the photophysics and for applications to artificial photosynthesis. Highly efficient ultrafast electron transfer from photoexcited conjugated polymers to C60 has been

  17. Characterizing aeroallergens by infrared spectroscopy of fungal spores and pollen.

    Directory of Open Access Journals (Sweden)

    Boris Zimmermann

    Full Text Available Fungal spores and plant pollen cause respiratory diseases in susceptible individuals, such as asthma, allergic rhinitis and hypersensitivity pneumonitis. Aeroallergen monitoring networks are an important part of treatment strategies, but unfortunately traditional analysis is time consuming and expensive. We have explored the use of infrared spectroscopy of pollen and spores for an inexpensive and rapid characterization of aeroallergens.The study is based on measurement of spore and pollen samples by single reflectance attenuated total reflectance Fourier transform infrared spectroscopy (SR-ATR FTIR. The experimental set includes 71 spore (Basidiomycota and 121 pollen (Pinales, Fagales and Poales samples. Along with fresh basidiospores, the study has been conducted on the archived samples collected within the last 50 years.The spectroscopic-based methodology enables clear spectral differentiation between pollen and spores, as well as the separation of confamiliar and congeneric species. In addition, the analysis of the scattering signals inherent in the infrared spectra indicates that the FTIR methodology offers indirect estimation of morphology of pollen and spores. The analysis of fresh and archived spores shows that chemical composition of spores is well preserved even after decades of storage, including the characteristic taxonomy-related signals. Therefore, biochemical analysis of fungal spores by FTIR could provide economical, reliable and timely methodologies for improving fungal taxonomy, as well as for fungal identification and monitoring. This proof of principle study shows the potential for using FTIR as a rapid tool in aeroallergen studies. In addition, the presented method is ready to be immediately implemented in biological and ecological studies for direct measurement of pollen and spores from flowers and sporocarps.

  18. Direct numerical simulation of MHD heat transfer in high Reynolds number turbulent channel flows for Prandtl number of 25

    International Nuclear Information System (INIS)

    Yamamoto, Yoshinobu; Kunugi, Tomoaki

    2015-01-01

    Graphical abstract: - Highlights: • For the first time, the MHD heat transfer DNS database corresponding to the typical nondimensional parameters of the fusion blanket design using molten salt, were established. • MHD heat transfer correlation was proposed and about 20% of the heat transfer degradation was evaluated under the design conditions. • The contribution of the turbulent diffusion to heat transfer is increased drastically with increasing Hartmann number. - Abstract: The high-Prandtl number passive scalar transport of the turbulent channel flow imposed a wall-normal magnetic field is investigated through the large-scale direct numerical simulation (DNS). All essential turbulence scales of velocities and temperature are resolved by using 2048 × 870 × 1024 computational grid points in stream, vertical, and spanwise directions. The heat transfer phenomena for a Prandtl number of 25 were observed under the following flow conditions: the bulk Reynolds number of 14,000 and Hartman number of up to 28. These values were equivalent to the typical nondimensional parameters of the fusion blanket design proposed by Wong et al. As a result, a high-accuracy DNS database for the verification of magnetohydrodynamic turbulent heat transfer models was established for the first time, and it was confirmed that the heat transfer correlation for a Prandtl number of 5.25 proposed by Yamamoto and Kunugi was applicable to the Prandtl number of 25 used in this study

  19. Direct numerical simulation of MHD heat transfer in high Reynolds number turbulent channel flows for Prandtl number of 25

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Yoshinobu, E-mail: yamamotoy@yamanashi.ac.jp [Department of Mechanical Systems Engineering, University of Yamanashi, 4-3-11 Takeda, Kofu 400-8511 (Japan); Kunugi, Tomoaki [Department of Nuclear Engineering, Kyoto University Yoshida, Sakyo, Kyoto 606-8501 (Japan)

    2015-01-15

    Graphical abstract: - Highlights: • For the first time, the MHD heat transfer DNS database corresponding to the typical nondimensional parameters of the fusion blanket design using molten salt, were established. • MHD heat transfer correlation was proposed and about 20% of the heat transfer degradation was evaluated under the design conditions. • The contribution of the turbulent diffusion to heat transfer is increased drastically with increasing Hartmann number. - Abstract: The high-Prandtl number passive scalar transport of the turbulent channel flow imposed a wall-normal magnetic field is investigated through the large-scale direct numerical simulation (DNS). All essential turbulence scales of velocities and temperature are resolved by using 2048 × 870 × 1024 computational grid points in stream, vertical, and spanwise directions. The heat transfer phenomena for a Prandtl number of 25 were observed under the following flow conditions: the bulk Reynolds number of 14,000 and Hartman number of up to 28. These values were equivalent to the typical nondimensional parameters of the fusion blanket design proposed by Wong et al. As a result, a high-accuracy DNS database for the verification of magnetohydrodynamic turbulent heat transfer models was established for the first time, and it was confirmed that the heat transfer correlation for a Prandtl number of 5.25 proposed by Yamamoto and Kunugi was applicable to the Prandtl number of 25 used in this study.

  20. Knockin' on pollen's door: live cell imaging of early polarization events in germinating Arabidopsis pollen

    Science.gov (United States)

    Vogler, Frank; Konrad, Sebastian S. A.; Sprunck, Stefanie

    2015-01-01

    Pollen tubes are an excellent system for studying the cellular dynamics and complex signaling pathways that coordinate polarized tip growth. Although several signaling mechanisms acting in the tip-growing pollen tube have been described, our knowledge on the subcellular and molecular events during pollen germination and growth site selection at the pollen plasma membrane is rather scarce. To simultaneously track germinating pollen from up to 12 genetically different plants we developed an inexpensive and easy mounting technique, suitable for every standard microscope setup. We performed high magnification live-cell imaging during Arabidopsis pollen activation, germination, and the establishment of pollen tube tip growth by using fluorescent marker lines labeling either the pollen cytoplasm, vesicles, the actin cytoskeleton or the sperm cell nuclei and membranes. Our studies revealed distinctive vesicle and F-actin polarization during pollen activation and characteristic growth kinetics during pollen germination and pollen tube formation. Initially, the germinating Arabidopsis pollen tube grows slowly and forms a uniform roundish bulge, followed by a transition phase with vesicles heavily accumulating at the growth site before switching to rapid tip growth. Furthermore, we found the two sperm cells to be transported into the pollen tube after the phase of rapid tip growth has been initiated. The method presented here is suitable to quantitatively study subcellular events during Arabidopsis pollen germination and growth, and for the detailed analysis of pollen mutants with respect to pollen polarization, bulging, or growth site selection at the pollen plasma membrane. PMID:25954283

  1. Chirality Transfer in Gold(I)-Catalysed Direct Allylic Etherifications of Unactivated Alcohols: Experimental and Computational Study.

    Science.gov (United States)

    Barker, Graeme; Johnson, David G; Young, Paul C; Macgregor, Stuart A; Lee, Ai-Lan

    2015-09-21

    Gold(I)-catalysed direct allylic etherifications have been successfully carried out with chirality transfer to yield enantioenriched, γ-substituted secondary allylic ethers. Our investigations include a full substrate-scope screen to ascertain substituent effects on the regioselectivity, stereoselectivity and efficiency of chirality transfer, as well as control experiments to elucidate the mechanistic subtleties of the chirality-transfer process. Crucially, addition of molecular sieves was found to be necessary to ensure efficient and general chirality transfer. Computational studies suggest that the efficiency of chirality transfer is linked to the aggregation of the alcohol nucleophile around the reactive π-bound Au-allylic ether complex. With a single alcohol nucleophile, a high degree of chirality transfer is predicted. However, if three alcohols are present, alternative proton transfer chain mechanisms that erode the efficiency of chirality transfer become competitive. © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

  2. Chemical constituents and free radical scavenging activity of corn pollen collected from Apis mellifera hives compared to floral corn pollen at Nan, Thailand

    Directory of Open Access Journals (Sweden)

    Chantarudee Atip

    2012-04-01

    Full Text Available Abstract Background Bee pollen is composed of floral pollen mixed with nectar and bee secretion that is collected by foraging honey (Apis sp. and stingless bees. It is rich in nutrients, such as sugars, proteins, lipids, vitamins and flavonoids, and has been ascribed antiproliferative, anti-allergenic, anti-angiogenic and free radical scavenging activities. This research aimed at a preliminary investigation of the chemical constituents and free radical scavenging activity in A. mellifera bee pollen. Methods Bee pollen was directly collected from A. mellifera colonies in Nan province, Thailand, in June, 2010, whilst floral corn (Zea mays L. pollen was collected from the nearby corn fields. The pollen was then sequentially extracted with methanol, dichloromethane (DCM and hexane, and each crude extract was tested for free radical scavenging activity using the DPPH assay, evaluating the percentage scavenging activity and the effective concentration at 50% (EC50. The most active crude fraction from the bee pollen was then further enriched for bioactive components by silica gel 60 quick and adsorption or Sephadex LH-20 size exclusion chromatography. The purity of all fractions in each step was observed by thin layer chromatography and the bioactivity assessed by the DPPH assay. The chemical structures of the most active fractions were analyzed by nuclear magnetic resonance. Results The crude DCM extract of both the bee corn pollen and floral corn pollen provided the highest active free radical scavenging activity of the three solvent extracts, but it was significantly (over 28-fold higher in the bee corn pollen (EC50 = 7.42 ± 0.12 μg/ml, than the floral corn pollen (EC50 = 212 ± 13.6% μg/ml. After fractionation to homogeneity, the phenolic hydroquinone and the flavone 7-O-R-apigenin were found as the minor and major bioactive compounds, respectively. Bee corn pollen contained a reasonably diverse array of nutritional components, including

  3. TRANSFER

    African Journals Online (AJOL)

    This paper reports on further studies on long range energy transfer between curcumine as donor and another thiazine dye, thionine, which is closely related to methylene blue as energy harvester (Figure 1). Since thionine is known to have a higher quantum yield of singlet oxygen sensitization than methylene blue [8], it is ...

  4. Spore Loads May Not be Used Alone as a Direct Indicator of the Severity of Nosema ceranae Infection in Honey Bees Apis mellifera (Hymenoptera:Apidae).

    Science.gov (United States)

    Zheng, Huo-Qing; Lin, Zhe-Guang; Huang, Shao-Kang; Sohr, Alex; Wu, Lyman; Chen, Yan Ping

    2014-12-01

    Nosema ceranae Fries et al., 1996, a microsporidian parasite recently transferred from Asian honey bees Apis cerana F., 1793, to European honey bees Apis mellifera L., 1758, has been suspected as one of the major culprits of the worldwide honey bee colony losses. Spore load is a commonly used criterion to describe the intensity of Nosema infection. In this study, by providing Nosema-infected bees with sterilized pollen, we confirmed that pollen feeding increased the spore loads of honey bees by several times either in the presence or absence of a queen. By changing the amount of pollen consumed by bees in cages, we showed that spore loads increased with an increase in pollen consumption. Nosema infections decrease honey bee longevity and transcription of vitellogenin, either with or without pollen feeding. However, the reduction of pollen consumption had a greater impact on honey bee longevity and vitellogenin level than the increase of spore counts caused by pollen feeding. These results indicate that spore loads may not be used alone as a direct indicator of the severity of N. ceranae infection in honey bees. © 2014 Entomological Society of America.

  5. Tunneling splitting in double-proton transfer: direct diagonalization results for porphycene.

    Science.gov (United States)

    Smedarchina, Zorka; Siebrand, Willem; Fernández-Ramos, Antonio

    2014-11-07

    Zero-point and excited level splittings due to double-proton tunneling are calculated for porphycene and the results are compared with experiment. The calculation makes use of a multidimensional imaginary-mode Hamiltonian, diagonalized directly by an effective reduction of its dimensionality. Porphycene has a complex potential energy surface with nine stationary configurations that allow a variety of tunneling paths, many of which include classically accessible regions. A symmetry-based approach is used to show that the zero-point level, although located above the cis minimum, corresponds to concerted tunneling along a direct trans - trans path; a corresponding cis - cis path is predicted at higher energy. This supports the conclusion of a previous paper [Z. Smedarchina, W. Siebrand, and A. Fernández-Ramos, J. Chem. Phys. 127, 174513 (2007)] based on the instanton approach to a model Hamiltonian of correlated double-proton transfer. A multidimensional tunneling Hamiltonian is then generated, based on a double-minimum potential along the coordinate of concerted proton motion, which is newly evaluated at the RI-CC2/cc-pVTZ level of theory. To make it suitable for diagonalization, its dimensionality is reduced by treating fast weakly coupled modes in the adiabatic approximation. This results in a coordinate-dependent mass of tunneling, which is included in a unique Hermitian form into the kinetic energy operator. The reduced Hamiltonian contains three symmetric and one antisymmetric mode coupled to the tunneling mode and is diagonalized by a modified Jacobi-Davidson algorithm implemented in the Jadamilu software for sparse matrices. The results are in satisfactory agreement with the observed splitting of the zero-point level and several vibrational fundamentals after a partial reassignment, imposed by recently derived selection rules. They also agree well with instanton calculations based on the same Hamiltonian.

  6. Direct Collapse to Supermassive Black Hole Seeds with Radiative Transfer: Isolated Halos

    Science.gov (United States)

    Luo, Yang; Ardaneh, Kazem; Shlosman, Isaac; Nagamine, Kentaro; Wise, John H.; Begelman, Mitchell C.

    2018-05-01

    Direct collapse within dark matter haloes is a promising path to form supermassive black hole seeds at high redshifts. The outer part of this collapse remains optically thin. However, the innermost region of the collapse is expected to become optically thick and requires to follow the radiation field in order to understand its evolution. So far, the adiabatic approximation has been used exclusively for this purpose. We apply radiative transfer in the flux-limited diffusion (FLD) approximation to solve the evolution of coupled gas and radiation for isolated haloes. We find that (1) the photosphere forms at 10-6 pc and rapidly expands outwards. (2) A central core forms, with a mass of 1 M⊙, supported by gas pressure gradients and rotation. (3) Growing gas and radiation pressure gradients dissolve it. (4) This process is associated with a strong anisotropic outflow; another core forms nearby and grows rapidly. (5) Typical radiation luminosity emerging from the photosphere is 5 × 1037-5 × 1038 erg s-1, of the order the Eddington luminosity. (6) Two variability time-scales are associated with this process: a long one, which is related to the accretion flow within the central 10-4-10-3 pc, and 0.1 yr, related to radiation diffusion. (7) Adiabatic models evolution differs profoundly from that of the FLD models, by forming a geometrically thick disc. Overall, an adiabatic equation of state is not a good approximation to the advanced stage of direct collapse, because the radiation is capable of escaping due to anisotropy in the optical depth and associated gradients.

  7. Ecological stoichiometry of the honeybee: Pollen diversity and adequate species composition are needed to mitigate limitations imposed on the growth and development of bees by pollen quality.

    Science.gov (United States)

    Filipiak, Michał; Kuszewska, Karolina; Asselman, Michel; Denisow, Bożena; Stawiarz, Ernest; Woyciechowski, Michał; Weiner, January

    2017-01-01

    The least understood aspects of the nutritional needs of bees are the elemental composition of pollen and the bees' need for a stoichiometrically balanced diet containing the required proportions of nutrients. Reduced plant diversity has been proposed as an indirect factor responsible for the pollinator crisis. We suggest stoichiometric mismatch resulting from a nutritionally unbalanced diet as a potential direct factor. The concentrations and stoichiometric ratios of C, N, S, P, K, Na, Ca, Mg, Fe, Zn, Mn, and Cu were studied in the bodies of honeybees of various castes and sexes and in the nectar and pollen of various plant species. A literature review of the elemental composition of pollen was performed. We identified possible co-limitations of bee growth and development resulting mainly from the scarcity of Na, S, Cu, P and K, and possibly Zn and N, in pollen. Particular castes and sexes face specific limitations. Concentrations of potentially limiting elements in pollen revealed high taxonomic diversity. High floral diversity may be necessary to maintain populations of pollen eaters. Single-species crop plantations, even if these species are rich in nectar and pollen, might limit bee growth and development, not allowing for gathering nutrients in adequate proportions. However, particular plant species may play greater roles than others in balancing honeybee diets. Therefore, we suggest specific plant species that may (1) ensure optimal growth and production of individuals by producing pollen that is exceptionally well balanced stoichiometrically (e.g., clover) or (2) prevent growth and development of honeybees by producing pollen that is extremely unbalanced for bees (e.g., sunflower). Since pollen is generally poor in Na, this element must be supplemented using "dirty water". Nectar cannot supplement the diet with limiting elements. Stoichiometric mismatch should be considered in intervention strategies aimed at improving the nutritional base for bees.

  8. Ecological stoichiometry of the honeybee: Pollen diversity and adequate species composition are needed to mitigate limitations imposed on the growth and development of bees by pollen quality.

    Directory of Open Access Journals (Sweden)

    Michał Filipiak

    Full Text Available The least understood aspects of the nutritional needs of bees are the elemental composition of pollen and the bees' need for a stoichiometrically balanced diet containing the required proportions of nutrients. Reduced plant diversity has been proposed as an indirect factor responsible for the pollinator crisis. We suggest stoichiometric mismatch resulting from a nutritionally unbalanced diet as a potential direct factor. The concentrations and stoichiometric ratios of C, N, S, P, K, Na, Ca, Mg, Fe, Zn, Mn, and Cu were studied in the bodies of honeybees of various castes and sexes and in the nectar and pollen of various plant species. A literature review of the elemental composition of pollen was performed. We identified possible co-limitations of bee growth and development resulting mainly from the scarcity of Na, S, Cu, P and K, and possibly Zn and N, in pollen. Particular castes and sexes face specific limitations. Concentrations of potentially limiting elements in pollen revealed high taxonomic diversity. High floral diversity may be necessary to maintain populations of pollen eaters. Single-species crop plantations, even if these species are rich in nectar and pollen, might limit bee growth and development, not allowing for gathering nutrients in adequate proportions. However, particular plant species may play greater roles than others in balancing honeybee diets. Therefore, we suggest specific plant species that may (1 ensure optimal growth and production of individuals by producing pollen that is exceptionally well balanced stoichiometrically (e.g., clover or (2 prevent growth and development of honeybees by producing pollen that is extremely unbalanced for bees (e.g., sunflower. Since pollen is generally poor in Na, this element must be supplemented using "dirty water". Nectar cannot supplement the diet with limiting elements. Stoichiometric mismatch should be considered in intervention strategies aimed at improving the nutritional base

  9. Induced sterility in petunia correlation between pollen and ovule fertilities

    International Nuclear Information System (INIS)

    Singh, I.S.

    1976-01-01

    An estimation of ovular fertility in petunia was carried out in order to show an eventual correlation between pollen and ovule fertilities. Two lines, TL-h 1 and Sf-1a, their F 1 hybrid and some pollen sterile plants isolated in M 1 after mutagenic treatments were vegetatively maintained in greenhouse. Data pollen fertility, number of ovules per ovary and number of seeds per capsule were obtained from each genotype. The ovule fertility was calculated as follows: mean number of seeds per capsule/mean number of ovules per ovary x 100. The analysis of variance detected: a highly significance variance component among genotypes, a highly significant differences between the sexes, and, a highly significant genotypes x sexes interaction. A highly significant positive correlation coefficient was found between pollen and ovule fertilities. Thus, it can be concluded that pollen and ovule fertilities may be affected in the same direction in the different mutant clones studied, but in a different manner from genotype to genotype [fr

  10. Urticaceae pollen concentration in the atmosphere of North Western Spain.

    Science.gov (United States)

    Vega-Maray, Ana Maria; Valencia-Barrera, Rosa; Fernandez-Gonzalez, Delia; Fraile, Roberto

    2003-01-01

    Plants of the Urticaceae family can develop into a pest on soils enriched with nitrogen. Urticaceae pollen is a biohazard because it elicits severe pollinosis. Pollen grains were sampled by using a Lanzoni seven-day-recording trap from February 1995-December 2000 in the atmosphere of the city of Ponferrada (Leon, North Western Spain). The Spearman test was used to analyse the statistical correlation between Urticaceae pollen and certain meteorological factors in different main pollination periods. Maximum values are reached in June and July, minimum levels are recorded in January and December. The parameters bearing the greatest positive influence on the occurrence of Urticaceae pollen grains are: temperature (maximum, minimum and mean), humidity (absolute, wet-bulb temperature, dew point and mixing ratio) and south western wind direction; negative parameters are: relative humidity, rainfall and period without wind. The highest correlation coefficients were obtained with temperature and wet-bulb. Absolute humidity and wet-bulb temperature yielded better correlation than relative humidity; hence, these two parameters must be included in this type of study. The use of one main pollination period or another in statistical analysis has an influence on the coefficient value. The behaviour of the pollen grains in the atmosphere during the year also influences the results.

  11. Polarized electrode enhances biological direct interspecies electron transfer for methane production in upflow anaerobic bioelectrochemical reactor.

    Science.gov (United States)

    Feng, Qing; Song, Young-Chae; Yoo, Kyuseon; Kuppanan, Nanthakumar; Subudhi, Sanjukta; Lal, Banwari

    2018-08-01

    The influence of polarized electrodes on the methane production, which depends on the sludge concentration, was investigated in upflow anaerobic bioelectrochemical (UABE) reactor. When the polarized electrode was placed in the bottom zone with a high sludge concentration, the methane production was 5.34 L/L.d, which was 53% higher than upflow anaerobic sludge blanket (UASB) reactor. However, the methane production was reduced to 4.34 L/L.d by placing the electrode in the upper zone of the UABE reactor with lower sludge concentration. In the UABE reactor, the methane production was mainly improved by the enhanced biological direct interspecies electron transfer (bDIET) pathway, and the methane production via the electrode was a minor fraction of less than 4% of total methane production. The polarized electrodes that placed in the bottom zone with a high sludge concentration enhance the bDIET for methane production in the UABE reactor and greatly improve the methane production. Copyright © 2018. Published by Elsevier Ltd.

  12. Direct evidence for radiative charge transfer after inner-shell excitation and ionization of large clusters

    Science.gov (United States)

    Hans, Andreas; Stumpf, Vasili; Holzapfel, Xaver; Wiegandt, Florian; Schmidt, Philipp; Ozga, Christian; Reiß, Philipp; Ben Ltaief, Ltaief; Küstner-Wetekam, Catmarna; Jahnke, Till; Ehresmann, Arno; Demekhin, Philipp V.; Gokhberg, Kirill; Knie, André

    2018-01-01

    We directly observe radiative charge transfer (RCT) in Ne clusters by dispersed vacuum-ultraviolet photon detection. The doubly ionized Ne2+-{{{N}}{{e}}}n-1 initial states of RCT are populated after resonant 1s-3p photoexcitation or 1s photoionization of Ne n clusters with ≈ 2800. These states relax further producing Ne+-Ne+-{{{N}}{{e}}}n-2 final states, and the RCT photon is emitted. Ab initio calculations assign the observed RCT signal to the{}{{{N}}{{e}}}2+(2{{{p}}}-2{[}1{{D}}]){--}{{{N}}{{e}}}n-1 initial state, while transitions from other possible initial states are proposed to be quenched by competing relaxation processes. The present results are in agreement with the commonly discussed scenario, where the doubly ionized atom in a noble gas cluster forms a dimer which dissipates its vibrational energy on a picosecond timescale. Our study complements the picture of the RCT process in weakly bound clusters, providing information which is inaccessible by charged particle detection techniques.

  13. A lactate electrochemical biosensor with a titanate nanotube as direct electron transfer promoter

    International Nuclear Information System (INIS)

    Yang Mingli; Wang Jin; Li Huaqing; Wu Nianqiang Nick; Zheng Jianguo

    2008-01-01

    Hydrogen titanate (H 2 Ti 3 O 7 ) nanotubes (TNTs) have been synthesized by a one-step hydrothermal processing. Lactate oxidase (LOx) enzyme has been immobilized on the three-dimensional porous TNT network to make an electrochemical biosensor for lactate detection. Cyclic voltammetry and amperometry tests reveal that the LOx enzyme, which is supported on TNTs, maintains their substrate-specific catalytic activity. The nanotubes offer the pathway for direct electron transfer between the electrode surface and the active redox centers of LOx, which enables the biosensor to operate at a low working potential and to avoid the influence of the presence of O 2 on the amperometric current response. The biosensor exhibits a sensitivity of 0.24 μA cm -2 mM -1 , a 90% response time of 5 s, and a linear response in the range from 0.5 to 14 mM and the redox center of enzyme obviates the need of redox mediators for electrochemical enzymatic sensors, which is attractive for the development of reagentless biosensors

  14. NO-γ emissions from streamer discharges: direct electron impact excitation versus resonant energy transfer

    International Nuclear Information System (INIS)

    Liu Ningyu; Pasko, Victor P

    2010-01-01

    It has been established that production of NO-γ emission in pulsed corona discharges is dominated by the energy transfer from N 2 (A 3 Σ u + ) to the NO ground state NO(X 2 Π r ) while direct excitation by electron impact is negligible. However, recent studies suggest that the electron impact excitation plays a more important role. In this work, we report modelling results of NO-γ emission associated with streamer discharges using two cross section data sets available in the literature. The first set was originally reported by Mojarrabi et al (1996 Phys. Rev. A 54 2977-82) and later updated by Brunger et al (2000 J. Phys. B: At. Mol. Opt. Phys. 33 809-19); the second set was published by Hayashi (1990 Nonequilibrium Processes in Partially Ionized Gases (NATO Advanced Science Institutes Series, Series B, Physics vol 220) ed M Capitelli and J N Bardsley (New York: Plenum) pp 333-40). According to the results, the role played by the electron impact excitation in the production of NO-γ is drastically different when different cross sections are used. The results indicate that the first data set leads to better agreement with experimental measurements. (fast track communication)

  15. Direct numerical simulation of turbulent concentric annular pipe flow Part 2: Heat transfer

    International Nuclear Information System (INIS)

    Chung, Seo Yoon; Sung, Hyung Jin

    2003-01-01

    A direct numerical simulation is performed for turbulent heat transfer in a concentric annulus at Re D h =8900 and Pr=0.71 for two radius ratios (R 1 /R 2 =0.1 and 0.5) and wall heat flux ratio q * =1.0. Main emphasis is placed on the transverse curvature effect on near-wall turbulent thermal structures. Near-wall turbulent thermal structures close to the inner and outer walls are scrutinized by computing the lower-order statistics. The fluctuating temperature variance and turbulent heat flux budgets are illustrated to confirm the results of the lower-order statistics. Probability density functions of the splat/anti-splat process are investigated to analyze the transverse curvature effect on the strong relationship between sweep and splat events. The present numerical results show that the turbulent thermal structures near the outer wall are more activated than those near the inner wall, which may be attributed to the different vortex regeneration processes between the inner and outer walls

  16. Challenges to develop nitrogen-fixing cereals by direct nif-gene transfer.

    Science.gov (United States)

    Curatti, Leonardo; Rubio, Luis M

    2014-08-01

    Some regions of the developing world suffer low cereal production yields due to low fertilizer inputs, among other factors. Biological N2 fixation, catalyzed by the prokaryotic enzyme nitrogenase, is an alternative to the use of synthetic N fertilizers. The molybdenum nitrogenase is an O2-labile metalloenzyme composed of the NifDK and NifH proteins, which biosyntheses require a number of nif gene products. A challenging strategy to increase cereal crop productivity in a scenario of low N fertilization is the direct transfer of nif genes into cereals. The sensitivity of nitrogenase to O2 and the apparent complexity of nitrogenase biosynthesis are the main barriers identified so far. Expression of active NifH requires the products of nifM, nifH, and possibly nifU and nifS, whereas active NifDK requires the products of nifH, nifD, nifK, nifB, nifE, nifN, and possibly nifU, nifS, nifQ, nifV, nafY, nifW and nifZ. Plastids and mitochondria are potential subcellular locations for nitrogenase. Both could provide the ATP and electrons required for nitrogenase to function but they differ in their internal O2 levels and their ability to incorporate ammonium into amino acids. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  17. A lactate electrochemical biosensor with a titanate nanotube as direct electron transfer promoter

    Science.gov (United States)

    Yang, Mingli; Wang, Jin; Li, Huaqing; Zheng, Jian-Guo; Wu, Nianqiang Nick

    2008-02-01

    Hydrogen titanate (H2Ti3O7) nanotubes (TNTs) have been synthesized by a one-step hydrothermal processing. Lactate oxidase (LOx) enzyme has been immobilized on the three-dimensional porous TNT network to make an electrochemical biosensor for lactate detection. Cyclic voltammetry and amperometry tests reveal that the LOx enzyme, which is supported on TNTs, maintains their substrate-specific catalytic activity. The nanotubes offer the pathway for direct electron transfer between the electrode surface and the active redox centers of LOx, which enables the biosensor to operate at a low working potential and to avoid the influence of the presence of O2 on the amperometric current response. The biosensor exhibits a sensitivity of 0.24 µA cm-2 mM-1, a 90% response time of 5 s, and a linear response in the range from 0.5 to 14 mM and the redox center of enzyme obviates the need of redox mediators for electrochemical enzymatic sensors, which is attractive for the development of reagentless biosensors.

  18. Highly sensitive and selective cholesterol biosensor based on direct electron transfer of hemoglobin.

    Science.gov (United States)

    Zhao, Changzhi; Wan, Li; Jiang, Li; Wang, Qin; Jiao, Kui

    2008-12-01

    A cholesterol biosensor based on direct electron transfer of a hemoglobin-encapsulated chitosan-modified glassy carbon electrode has been developed for highly sensitive and selective analysis of serum samples. Modified by films containing hemoglobin and cholesterol oxidase, the electrode was prepared by encapsulation of enzyme in chitosan matrix. The hydrogen peroxide produced by the catalytic oxidation of cholesterol by cholesterol oxidase was reduced electrocatalytically by immobilized hemoglobin and used to obtain a sensitive amperometric response to cholesterol. The linear response of cholesterol concentrations ranged from 1.00 x 10(-5) to 6.00 x 10(-4) mol/L, with a correlation coefficient of 0.9969 and estimated detection limit of cholesterol of 9.5 micromol/L at a signal/noise ratio of 3. The cholesterol biosensor can efficiently exclude interference by the commonly coexisting ascorbic acid, uric acid, dopamine, and epinephrine. The sensitivity to the change in the concentration of cholesterol as the slope of the calibration curve was 0.596 A/M. The relative standard deviation was under 4.0% (n=5) for the determination of real samples. The biosensor is satisfactory in the determination of human serum samples.

  19. Effects of an applied voltage on direct interspecies electron transfer via conductive materials for methane production.

    Science.gov (United States)

    Lee, Jung-Yeol; Park, Jeong-Hoon; Park, Hee-Deung

    2017-10-01

    Direct interspecies electron transfer (DIET) between exoelectrogenic bacteria and methanogenic archaea via conductive materials is reported as an efficient method to produce methane in anaerobic organic waste digestion. A voltage can be applied to the conductive materials to accelerate the DIET between two groups of microorganisms to produce methane. To evaluate this hypothesis, two sets of anaerobic serum bottles with and without applied voltage were used with a pair of graphite rods as conductive materials to facilitate DIET. Initially, the methane production rate was similar between the two sets of serum bottles, and later the serum bottles with an applied voltage of 0.39V showed a 168% higher methane production rate than serum bottles without an applied voltage. In cyclic voltammograms, the characteristic redox peaks for hydrogen and acetate oxidation were identified in the serum bottles with an applied voltage. In the microbial community analyses, hydrogenotrophic methanogens (e.g. Methanobacterium) were observed to be abundant in serum bottles with an applied voltage, while methanogens utilizing carbon dioxide (e.g., Methanosaeta and Methanosarcina) were dominant in serum bottles without an applied voltage. Taken together, the applied voltage on conductive materials might not be effective to promote DIET in methane production. Instead, it appeared to generate a condition for hydrogenotrophic methanogenesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Gibberellin regulates pollen viability and pollen tube growth in rice.

    Science.gov (United States)

    Chhun, Tory; Aya, Koichiro; Asano, Kenji; Yamamoto, Eiji; Morinaka, Yoichi; Watanabe, Masao; Kitano, Hidemi; Ashikari, Motoyuki; Matsuoka, Makoto; Ueguchi-Tanaka, Miyako

    2007-12-01

    Gibberellins (GAs) play many biological roles in higher plants. We collected and performed genetic analysis on rice (Oryza sativa) GA-related mutants, including GA-deficient and GA-insensitive mutants. Genetic analysis of the mutants revealed that rice GA-deficient mutations are not transmitted as Mendelian traits to the next generation following self-pollination of F1 heterozygous plants, although GA-insensitive mutations are transmitted normally. To understand these differences in transmission, we examined the effect of GA on microsporogenesis and pollen tube elongation in rice using new GA-deficient and GA-insensitive mutants that produce semifertile flowers. Phenotypic analysis revealed that the GA-deficient mutant reduced pollen elongation1 is defective in pollen tube elongation, resulting in a low fertilization frequency, whereas the GA-insensitive semidominant mutant Slr1-d3 is mainly defective in viable pollen production. Quantitative RT-PCR revealed that GA biosynthesis genes tested whose mutations are transmitted to the next generation at a lower frequency are preferentially expressed after meiosis during pollen development, but expression is absent or very low before the meiosis stage, whereas GA signal-related genes are actively expressed before meiosis. Based on these observations, we predict that the transmission of GA-signaling genes occurs in a sporophytic manner, since the protein products and/or mRNA transcripts of these genes may be introduced into pollen-carrying mutant alleles, whereas GA synthesis genes are transmitted in a gametophytic manner, since these genes are preferentially expressed after meiosis.

  1. Does stronger pollen competition improve offspring fitness when pollen load does not vary?

    Science.gov (United States)

    Pélabon, Christophe; Hennet, Lauriane; Bolstad, Geir H; Albertsen, Elena; Opedal, Øystein H; Ekrem, Runa K; Armbruster, W Scott

    2016-03-01

    Competition among pollen grains from a single donor is expected to increase the quality of the offspring produced because of the recessive deleterious alleles expressed during pollen-tube growth. However, evidence for such an effect is inconclusive; a large number of studies suffer from confounding variation in pollen competition with variation in pollen load. In this study, we tested the effect of pollen competition on offspring performance independently of pollen-load variation. We compared seed mass and early seedling performance in Dalechampia scandens (Euphorbiaceae) between crosses in which variation in pollen competition was achieved, without variation in pollen load, by manipulating the dispersion of pollen grains on the stigmas. Despite a large sample size (211 crosses on 20 maternal plants), we failed to find an effect of pollen competition on seed characteristics or early seedling performance. Paternal effects were always limited, and pollen competition never reduced the within-father (residual) variance. These results suggest that limited within-donor variation in genetic quality of pollen grains reduces the potential benefits of pollen competition in the study population. The lack of paternal effects on early sporophyte performance further suggests that benefits of pollen competition among pollen from multiple donors should be limited as well, and it raises questions about the significance of pollen competition as a mechanism of sexual selection. © 2016 Botanical Society of America.

  2. Experimental measurement of the interfacial heat transfer coefficients of subcooled flow boiling using micro-thermocouple and double directional images

    International Nuclear Information System (INIS)

    Seong-Jin Kim; Goon-Cherl Park

    2005-01-01

    Full text of publication follows: Models or correlations for phase interface are needed to analyze the multi-phase flow. Interfacial heat transfer coefficients are important to constitute energy equation of multi-phase flow, specially. In subcooled boiling flow, bubble condensation at the bubble-liquid interface is a major mechanism of heat transfer within bulk subcooled liquid. Bubble collapse rates and temperatures of each phase are needed to determine the interfacial heat transfer coefficient for bubble condensation. Bubble collapse rates were calculated through image processing in single direction, generally. And in case of liquid bulk temperature, which has been obtained by general temperature sensor such as thermocouple, was used. However, multi-directional images are needed to analyze images due to limitations of single directional image processing. Also, temperature sensor, which has a fast response time, must be used to obtain more accurate interfacial heat transfer coefficient. Low pressure subcooled water flow experiments using micro-thermocouple and double directional image processing with mirrors were conducted to investigate bubble condensation phenomena and to modify interfacial heat transfer correlation. Experiments were performed in a vertical subcooled boiling flow of a rectangular channel. Bubble condensing traces with respect to time were recorded by high speed camera in double direction and bubble collapse rates were calculated by processing recorded digital images. Temperatures were measured by micro-thermocouple, which is a K-type with a 12.7 μm diameter. The liquid temperature was estimated by the developed algorithm to discriminate phases and find each phase temperature in the measured temperature including both liquid and bubble temperature. The interfacial heat transfer coefficient for bubble condensation was calculated from the bubble collapse rates and the estimated liquid temperature, and its correlation was modified. The modified

  3. National Allergy Bureau Pollen and Mold Report

    Science.gov (United States)

    ... Search AAAAI National Allergy Bureau Pollen and Mold Report Date: May 19, 2018 Location: San Antonio (2), ... 18/2018 ( click here to view ). Our Allergen Report Email Service can automatically email you daily pollen ...

  4. Study of mass and momentum transfer and their effect on the direct fluorination of uranium oxide

    International Nuclear Information System (INIS)

    Cross, P.E.

    1983-01-01

    The mechanism for the fluorination of solid U 3 O 8 to gaseous UF 6 was found to be a two-step process with solid UO 2 F 2 as an intermediate. The highest particle temperatures were found to be associated with the initial reaction step to UO 2 F 2 ; it was recommended that these temperatures be maintained below 1700 0 F. The chemical equilibrium constant for the fluorination of PuF 4 to PuF 6 was found to be unexpectedly low at typical flame tower temperatures. Although not confirmed, there is an indication in the literature that a similar equilibrium constant is associated with the fluorination of NpF 4 and other transuranic molecules. It was recommended that uranium oxides which are significantly contaminated with transuranics should not be processed through a direct fluorination reactor such as the UF 6 flame tower. Reaction rate equations were developed for the fluorination of U 3 O 8 , UF 4 , PuF 4 and NpF 4 . During the course of the development, a significant discrepancy was found in the literature for the activation energy of the fluorination of U 3 O 8 . Equations were developed for both a high and low limit rate constant for the fluorination of U 3 O 8 . A variey of momentum, heat and mass transfer equations were developed for both oxide particles and the gas phase within the flame tower. Equations were developed to estimate the physical and transport properties of each gaseous component and the gas mixture as a whole. These properties and the transport equations were used to estimate the reaction time and distance for oxide particles with both the low and high limit reaction rate constant. The procedures used to perform these calculations is limited to constant temperature and an oxide feed comprised of a single particle size. The results indicate that above 1000 0 F the mass transfer of reactants and products becomes increasingly important to the overall rate of the reaction

  5. Stigma-pollen recognition: a new look

    Directory of Open Access Journals (Sweden)

    C. Dumas

    2014-01-01

    Full Text Available During the last two decades, there have been several conceptual developments in our understanding of pollen-stigma recognition and molecular mechanisms involved. The main models proposed are compared. Based on additional data a hypothesis to complete these models especially for pollen hydration and adhesion is proposed. After attachment of the pollen to the stigma surface a close interaction exists involving lipoproteic membrane-like compounds (pollenkitt and stigma pellicle and pollen agglutinating ability.

  6. Effects of fluorides and sulphur dioxide on pollen germination and growth of the pollen tube

    Directory of Open Access Journals (Sweden)

    Leon Mejnartowicz

    2014-01-01

    Full Text Available The action of fluorides and sulphur dioxides from emissions from a phosphate fertilizer factory significantly reduced the germination of Scots pine pollen grains. The pollen tube length indicated that its growth is uninhibited even though the pollen was collected under conditions of air-pollution. There are statistically significant differences showing longer tubes in the sensitive trees pollen grains. l he ageing of pollen from the sensitive trees occurs probably more rapidly than in the tolerant trees.

  7. Infrared photoexcitation spectroscopy of conducting polymer and C60 composites: direct evidence of photo-induced electron transfer

    NARCIS (Netherlands)

    Lee, Kwanghee; Janssen, R.A.J.; Sariciftci, N.S.; Heeger, A.J.

    1994-01-01

    We report direct spectral evidence of photoinduced electron transfer from the excited state of conducting polymer onto C60 by infrared photoexcitation spectroscopy, from 0.01 eV (100 cm-1) to 1.3 eV (11,000 cm-1). The photoinduced absorption spectra of poly(3-octylthiophene) (P30T) and

  8. Transfer of Direct and Moiré Patterns by Reactive Ion Etching Through Ex Situ Fabricated Nanoporous Polymer Masks

    DEFF Research Database (Denmark)

    Shvets, Violetta; Hentschel, Thomas; Schulte, Lars

    2015-01-01

    modification, which are essential prerequisites for the conventional procedure of block copolymer directed self-assembly. The demonstrated elliptic and moire pattern transfers prove that the proposed ex situ procedure allows us to realize nanolithographic patterns that are difficult to realize...

  9. PhosphoLipid transfer protein (PLTP) exerts a direct pro-inflammatory effect on rheumatoid arthritis (RA) fibroblasts-like-synoviocytes (FLS) independently of its lipid transfer activity

    Science.gov (United States)

    Deckert, Valérie; Daien, Claire I.; Che, Hélène; Elhmioui, Jamila; Lemaire, Stéphanie; Pais de Barros, Jean-Paul; Desrumaux, Catherine; Combe, Bernard; Hahne, Michael; Lagrost, Laurent; Morel, Jacques

    2018-01-01

    Rheumatoid arthritis (RA) is a chronic inflammatory rheumatic disease with modification of lipids profile and an increased risk of cardiovascular events related to inflammation. Plasma phospholipid transfer protein (PLTP) exerts a lipid transfer activity through its active form. PLTP can also bind to receptors such as ATP-binding cassette transporter A1 (ABCA1). In addition to its role in lipoprotein metabolism and atherosclerosis, the latest advances came in support of a complex role of PLTP in the regulation of the inflammatory response, both with pro-inflammatory or anti-inflammatory properties. The aim of the present study was to decipher the role of PLTP in joint inflammation and to assess its relevance in the context of RA. PLTP expression was examined by western-blot and by immunochemistry. ABCA1 expression was analyzed by flow cytometry. Lipid transfer activity of PLTP and pro-inflammatory cytokines were measured in sera and synovial fluid (SF) from RA patients and controls (healthy subjects or osteoarthritis patients [OA]). FLS were treated with both lipid-transfer active form and inactive form of recombinant human PLTP. IL-8, IL-6, VEGF and MMP3 produced by FLS were assessed by ELISA, and proliferation by measuring 3H-Thymidine incorporation. RA synovial tissues showed higher PLTP staining than OA and PLTP protein levels were also significantly higher in RA-FLS. In addition, RA, unlike OA patients, displayed elevated levels of PLTP activity in SF, which correlated with pro-inflammatory cytokines. Both lipid-transfer active and inactive forms of PLTP significantly increased the production of cytokines and proliferation of FLS. ABCA1 was expressed on RAFLS and PLTP activated STAT3 pathway. To conclude, PLTP is highly expressed in the joints of RA patients and may directly trigger inflammation and FLS proliferation, independently of its lipid transfer activity. These results suggest a pro-inflammatory role for PLTP in RA. PMID:29565987

  10. Direct interaction between linear electron transfer chains and solute transport systems in bacteria

    NARCIS (Netherlands)

    Elferink, Marieke G.L.; Hellingwerf, Klaas J.; Belkum, Marco J. van; Poolman, Bert; Konings, Wil N.

    1984-01-01

    In studies on alanine and lactose transport in Rhodopseudomonas sphaeroides we have demonstrated that the rate of solute uptake in this phototrophic bacterium is regulated by the rate of light-induced cyclic electron transfer. In the present paper the interaction between linear electron transfer

  11. Glucose oxidase anode for biofuel cell based on direct electron transfer

    Energy Technology Data Exchange (ETDEWEB)

    Ivnitski, Dmitri; Branch, Brittany; Atanassov, Plamen [Department of Chemical and Nuclear Engineering, University of New Mexico, 209 Farris Engineering Center, Room 150, Albuquerque, NM 87131-0001 (United States); Apblett, Christopher [Sandia National Laboratories, Albuquerque, NM 87185 (United States)

    2006-08-15

    This paper presents a new design concept of a glucose oxidase (GO{sub x}) electrode as an anode for the biofuel cell based on direct electron transfer (DET) between the active site of an enzyme and the multi-walled carbon nanotube (MWNT)-modified electrode surface. Toray{sup (R)} carbon paper (TP) with a porous three-dimensional network (78% porosity) was used as a matrix for selectively growing multi-walled carbon nanotubes. The incorporation of MWCNTs into TP was provided by the chemical vapor deposition technique after an electrochemical transition of cobalt metal seeds. This approach has the ability to efficiently promote DET reactions. The morphologies and electrochemical characteristics of the GO{sub x} modified electrodes were investigated by scanning electron microscopy, cyclic voltammetry, and potentiometric methods. The combination of poly-cation polyethylenimine (PEI) with negatively charged glucose oxidase provides formation of circa 100nm thick films on the TP/MWCNT surface. The tetrabutylammonium bromide salt-treated Nafion{sup (R)} was used as GO{sub x} binder and proton-conducting medium. The TP/MWCNT/PEI/GO{sub x}/Nafion{sup (R)} modified electrode operates at 25{sup o}C in 0.02M phosphate buffer solution (pH 6.9) containing 0.1M KCl in the presence of 20mM glucose. The open circuit potential of GO{sub x} anode was between -0.38V and -0.4V vs. Ag/AgCl, which is closer to the redox potential of the FAD/FADH{sub 2} cofactor in the enzyme itself. The GO{sub x} electrode has a potential to work in vivo by using endogenous substances, such as glucose and oxygen. Such a glucose anode allows for the development of a new generation of miniaturized membrane-less biofuel cells. (author)

  12. NORM - Radionuclide transfer studies - A modern approach according Directive 2013/59/EURATOM

    International Nuclear Information System (INIS)

    Prlic, Ivica; Hajdinjak, Mladen

    2014-01-01

    Regarding NORM, Directive applies in particular to human activities which involve the presence of natural radiation sources that lead to a significant increase in the exposure of workers or members of the public, in particular the processing of materials with naturally-occurring radionuclides (NORM) and the exposure of workers or members of the public to indoor radon, the external exposure from building materials and cases of lasting exposure resulting from the after-effects of an emergency or a past human activity. For areas with long-lasting residual contamination in which the Member State has decided to allow habitation and the resumption of social and economic activities, Member States shall ensure, in consultation with stakeholders, that arrangements are in place, as necessary, for the ongoing control of exposure with the aim of establishing living conditions that can be considered as normal. For building materials which are identified by the Member State as being of concern from a radiation protection point of view, Member State shall ensure that, before such materials are placed on the market the activity concentration index I is determined. The index relates to the gamma radiation dose derived throughout the radionuclide transfer studies, in excess of typical outdoor exposure, in a building constructed from a specified building material. The index applies to the building material, not to its constituents except when those constituents are building materials themselves and are separately assessed as such. The calculation of dose needs to take into account other factors such as density, thickness of the material as well as factors relating to the type of building and the intended use of the material (bulk or superficial). (authors)

  13. Direct electrochemistry and intramolecular electron transfer of ascorbate oxidase confined on L-cysteine self-assembled gold electrode.

    Science.gov (United States)

    Patil, Bhushan; Kobayashi, Yoshiki; Fujikawa, Shigenori; Okajima, Takeyoshi; Mao, Lanqun; Ohsaka, Takeo

    2014-02-01

    A direct electrochemistry and intramolecular electron transfer of multicopper oxidases are of a great importance for the fabrication of these enzyme-based bioelectrochemical-devices. Ascorbate oxidase from Acremonium sp. (ASOM) has been successfully immobilized via a chemisorptive interaction on the l-cysteine self-assembled monolayer modified gold electrode (cys-SAM/AuE). Thermodynamics and kinetics of adsorption of ASOM on the cys-SAM/AuE were studied using cyclic voltammetry. A well-defined redox wave centered at 166±3mV (vs. Ag│AgCl│KCl(sat.)) was observed in 5.0mM phosphate buffer solution (pH7.0) at the fabricated ASOM electrode, abbreviated as ASOM/cys-SAM/AuE, confirming a direct electrochemistry, i.e., a direct electron transfer (DET) between ASOM and cys-SAM/AuE. The direct electrochemistry of ASOM was further confirmed by taking into account the chemical oxidation of ascorbic acid (AA) by O2 via an intramolecular electron transfer in the ASOM as well as the electrocatalytic oxidation of AA at the ASOM/cys-SAM/AuE. Thermodynamics and kinetics of the adsorption of ASOM on the cys-SAM/AuE have been elaborated along with its direct electron transfer at the modified electrodes on the basis of its intramolecular electron transfer and electrocatalytic activity towards ascorbic acid oxidation and O2 reduction. ASOM saturated surface area was obtained as 2.41×10(-11)molcm(-2) with the apparent adsorption coefficient of 1.63×10(6)Lmol(-1). The ASOM confined on the cys-SAM/AuE possesses its essential enzymatic function. © 2013.

  14. Functional role of long-lived flowers in preventing pollen limitation in a high elevation outcrossing species.

    Science.gov (United States)

    Arroyo, Mary T K; Pacheco, Diego Andrés; Dudley, Leah S

    2017-11-01

    Low pollinator visitation in harsh environments may lead to pollen limitation which can threaten population persistence. Consequently, avoidance of pollen limitation is expected in outcrossing species subjected to habitually low pollinator service. The elevational decline in visitation rates on many high mountains provides an outstanding opportunity for addressing this question. According to a recent meta-analysis, levels of pollen limitation in alpine and lowland species do not differ. If parallel trends are manifested among populations of alpine species with wide elevational ranges, how do their uppermost populations contend with lower visitation? We investigated visitation rates and pollen limitation in high Andean Rhodolirium montanum . We test the hypothesis that lower visitation rates at high elevations are compensated for by the possession of long-lived flowers. Visitation rates decreased markedly over elevation as temperature decreased. Pollen limitation was absent at the low elevation site but did occur at the high elevation site. While initiation of stigmatic pollen deposition at high elevations was not delayed, rates of pollen arrival were lower, and cessation of pollination, as reflected by realized flower longevity, occurred later in the flower lifespan. Comparison of the elevational visitation decline and levels of pollen limitation indicates that flower longevity partially compensates for the lower visitation rates at high elevation. The functional role of flower longevity, however, was strongly masked by qualitative pollen limitation arising from higher abortion levels attributable to transference of genetically low-quality pollen in large clones. Stronger clonal growth at high elevations could counterbalance the negative fitness consequences of residual pollen limitation due to low visitation rates and/or difficult establishment under colder conditions. Visitation rates on the lower part of the elevational range greatly exceeded community rates

  15. Analysis of Tube Bank Heat Transfer In Downward Directed Foam Flow

    Directory of Open Access Journals (Sweden)

    Jonas Gylys

    2004-06-01

    Full Text Available Apparatus with the foam flow are suitable to use in different technologies like heat exchangers, food industry, chemical and oil processing industry. Statically stable liquid foam until now is used in technologic systems rather seldom. Although a usage of this type of foam as heat transfer agent in foam equipment has a number of advantages in comparison with one phase liquid equipment: small quantity of liquid is required, heat transfer rate is rather high, mass of equipment is much smaller, energy consumption for foam delivery into heat transfer zone is lower. The paper analyzes the peculiarities of heat transfer from distributed in staggered order and perpendicular to foam flow in channel of rectangular cross section tube bundle to the foam flow. It was estimated the dependence of mean gas velocity and volumetric void fraction of foam flow to heat transfer in downward foam flow. Significant difference of heat transfer intensity from front and back tubes of tube row in laminar foam flow was noticed. Dependence of heat transfer on flow velocity and volumetric void fraction of foam was confirmed and estimated by criterion equations.

  16. Wind tunnel and field assessment of pollen dispersal in soybean [Glycine max (L.) Merr.].

    Science.gov (United States)

    Yoshimura, Yasuyuki

    2011-01-01

    Although genetically modified (GM) soybean has never been cultivated commercially in Japan, it is essential to set up the isolation distance required to prevent out-crossing between GM and conventional soybean in preparation for any future possibility of pollen transfer. The airborne soybean pollen was sampled using some Durham pollen samplers located in the range of 20 m from the field edge. In addition, the dispersal distance was assessed in a wind tunnel under constant air flow and then it was compared with the anticipated distances based on the pollen diameter. In the field, the maximum pollen density per day observed was 1.235 grains cm(-2) day(-1) at three observation points within 2.5 m from the field and inside the field the mean density did not reach the rate of 1 grain cm(-2 )day(-1) during 19 flowering days. The results of the wind tunnel experiment also showed that the plants had almost no airborne release of pollen and the dispersal distance was shorter than theoretical value due to clustered dispersal. This study showed little airborne pollen in and around the soybean field and the dispersal is restricted to a small area. Therefore, wind-mediated pollination appears to be negligible.

  17. Statistical Models for Inferring Vegetation Composition from Fossil Pollen

    Science.gov (United States)

    Paciorek, C.; McLachlan, J. S.; Shang, Z.

    2011-12-01

    Fossil pollen provide information about vegetation composition that can be used to help understand how vegetation has changed over the past. However, these data have not traditionally been analyzed in a way that allows for statistical inference about spatio-temporal patterns and trends. We build a Bayesian hierarchical model called STEPPS (Spatio-Temporal Empirical Prediction from Pollen in Sediments) that predicts forest composition in southern New England, USA, over the last two millenia based on fossil pollen. The critical relationships between abundances of tree taxa in the pollen record and abundances in actual vegetation are estimated using modern (Forest Inventory Analysis) data and (witness tree) data from colonial records. This gives us two time points at which both pollen and direct vegetation data are available. Based on these relationships, and incorporating our uncertainty about them, we predict forest composition using fossil pollen. We estimate the spatial distribution and relative abundances of tree species and draw inference about how these patterns have changed over time. Finally, we describe ongoing work to extend the modeling to the upper Midwest of the U.S., including an approach to infer tree density and thereby estimate the prairie-forest boundary in Minnesota and Wisconsin. This work is part of the PalEON project, which brings together a team of ecosystem modelers, paleoecologists, and statisticians with the goal of reconstructing vegetation responses to climate during the last two millenia in the northeastern and midwestern United States. The estimates from the statistical modeling will be used to assess and calibrate ecosystem models that are used to project ecological changes in response to global change.

  18. A Simple, Inexpensive Pollen Trap

    Science.gov (United States)

    P. E. Hoekstra

    1965-01-01

    Pollen plays a role of vital importance in the sexual reproduction of all plants but it is especially important in forestry. With few exceptions, sexual reproduction is the only link between succeeding generations in the forest. To be sure, vegetative reproduction is important for special purposes, but it will probably not be used on a mass scale in timber...

  19. Comparison of Heat Transfer Fluid and Direct Steam Generation technologies for Integrated Solar Combined Cycles

    International Nuclear Information System (INIS)

    Rovira, Antonio; Montes, María José; Varela, Fernando; Gil, Mónica

    2013-01-01

    At present time and in the medium term, Solar Thermal Power Plants are going to share scenario with conventional energy generation technologies, like fossil and nuclear. In such a context, Integrated Solar Combined Cycles (ISCCs) may be an interesting choice since integrated designs may lead to a very efficient use of the solar and fossil resources. In this work, different ISCC configurations including a solar field based on parabolic trough collectors and working with the so-called Heat Transfer Fluid (HTF) and Direct Steam Generation (DSG) technologies are compared. For each technology, four layouts have been studied: one in which solar heat is used to evaporate part of the high pressure steam of a bottoming Rankine cycle with two pressure levels, another that incorporates a preheating section to the previous layout, the third one that includes superheating instead of preheating and the last one including both preheating and superheating in addition to the evaporation. The analysis is made with the aim of finding out which of the different layouts reaches the best performance. For that purpose, three types of comparisons have been performed. The first one assesses the benefits of including a solar steam production fixed at 50 MW th . The second one compares the configurations with a standardised solar field size instead of a fixed solar steam production. Finally, the last one consists on an even more homogeneous comparison considering the same steam generator size for all the configurations as well as standardised solar fields. The configurations are studied by mean of exergy analyses. Several figures of merit are used to correctly assess the configurations. Results reveal that the only-evaporative DSG configuration becomes the best choice, since it benefits of both low irreversibility at the heat recovery steam generator and high thermal efficiency in the solar field. Highlights: ► ISCC configurations with DSG and HTF technologies are compared. ► Four

  20. External application of gametophyte-specific ZmPMEI1 induces pollen tube burst in maize.

    Science.gov (United States)

    Woriedh, Mayada; Wolf, Sebastian; Márton, Mihaela L; Hinze, Axel; Gahrtz, Manfred; Becker, Dirk; Dresselhaus, Thomas

    2013-09-01

    Regulated demethylesterification of homogalacturonan, a major component of plant cell walls, by the activity of pectin methylesterases (PMEs), plays a critical role for cell wall stability and integrity. Especially fast growing plant cells such as pollen tubes secrete large amounts of PMEs toward their apoplasmic space. PME activity itself is tightly regulated by its inhibitor named as PME inhibitor and is thought to be required especially at the very pollen tube tip. We report here the identification and functional characterization of PMEI1 from maize (ZmPMEI1). We could show that the protein acts as an inhibitor of PME but not of invertases and found that its gene is strongly expressed in both gametophytes (pollen grain and embryo sac). Promoter reporter studies showed gene activity also during pollen tube growth toward and inside the transmitting tract. All embryo sac cells except the central cell displayed strong expression. Weaker signals were visible at sporophytic cells of the micropylar region. ZmPMEI1-EGFP fusion protein is transported within granules inside the tube and accumulates at the pollen tube tip as well as at sites where pollen tubes bend and/or change growth directions. The female gametophyte putatively influences pollen tube growth behavior by exposing it to ZmPMEI1. We therefore simulated this effect by applying recombinant protein at different concentrations on growing pollen tubes. ZmPMEI1 did not arrest growth, but destabilized the cell wall inducing burst. Compared with female gametophyte secreted defensin-like ZmES4, which induces burst at the very pollen tube tip, ZmPMEI1-induced burst occurs at the subapical region. These findings indicate that ZmPMEI1 secreted by the embryo sac likely destabilizes the pollen tube wall during perception and together with other proteins such as ZmES4 leads to burst and thus sperm release.

  1. Satellite Phenology Observations Inform Peak Season of Allergenic Grass Pollen Aerobiology across Two Continents

    Science.gov (United States)

    Huete, A. R.; Devadas, R.; Davies, J.

    2015-12-01

    Pollen exposure and prevalence of allergenic diseases have increased in many parts of the world during the last 30 years, with exposure to aeroallergen grass pollen expected to intensify with climate change, raising increased concerns for allergic diseases. The primary contributing factors to higher allergenic plant species presence are thought to be climate change, land conversion, and biotic mixing of species. Conventional methods for monitoring airborne pollen are hampered by a lack of sampling sites and heavily rely on meteorology with less attention to land cover updates and monitoring of key allergenic species phenology stages. Satellite remote sensing offers an alternative method to overcome the restrictive coverage afforded by in situ pollen networks by virtue of its synoptic coverage and repeatability of measurements that enable timely updates of land cover and land use information and monitoring landscape dynamics and interactions with human activity and climate. In this study, we assessed the potential of satellite observations of urban/peri-urban environments to directly inform landscape conditions conducive to pollen emissions. We found satellite measurements of grass cover phenological evolution to be highly correlated with in situ aerobiological grass pollen concentrations in five urban centres located across two hemispheres (Australia and France). Satellite greenness data from the Moderate Resolution Imaging Spectroradiometer (MODIS) were found to be strongly synchronous with grass pollen aerobiology in both temperate grass dominated sites (France and Melbourne), as well as in Sydney, where multiple pollen peaks coincided with the presence of subtropical grasses. Employing general additive models (GAM), the satellite phenology data provided strong predictive capabilities to inform airborne pollen levels and forecast periods of grass pollen emissions at all five sites. Satellite phenology offer promising opportunities of improving public health risk

  2. Classification of grass pollen through the quantitative analysis of surface ornamentation and texture.

    Science.gov (United States)

    Mander, Luke; Li, Mao; Mio, Washington; Fowlkes, Charless C; Punyasena, Surangi W

    2013-11-07

    Taxonomic identification of pollen and spores uses inherently qualitative descriptions of morphology. Consequently, identifications are restricted to categories that can be reliably classified by multiple analysts, resulting in the coarse taxonomic resolution of the pollen and spore record. Grass pollen represents an archetypal example; it is not routinely identified below family level. To address this issue, we developed quantitative morphometric methods to characterize surface ornamentation and classify grass pollen grains. This produces a means of quantifying morphological features that are traditionally described qualitatively. We used scanning electron microscopy to image 240 specimens of pollen from 12 species within the grass family (Poaceae). We classified these species by developing algorithmic features that quantify the size and density of sculptural elements on the pollen surface, and measure the complexity of the ornamentation they form. These features yielded a classification accuracy of 77.5%. In comparison, a texture descriptor based on modelling the statistical distribution of brightness values in image patches yielded a classification accuracy of 85.8%, and seven human subjects achieved accuracies between 68.33 and 81.67%. The algorithmic features we developed directly relate to biologically meaningful features of grass pollen morphology, and could facilitate direct interpretation of unsupervised classification results from fossil material.

  3. DETECTION OF WHITE DWARF COMPANIONS TO BLUE STRAGGLERS IN THE OPEN CLUSTER NGC 188: DIRECT EVIDENCE FOR RECENT MASS TRANSFER

    Energy Technology Data Exchange (ETDEWEB)

    Gosnell, Natalie M.; Mathieu, Robert D. [Department of Astronomy, University of Wisconsin - Madison, 475 N. Charter St., Madison, WI 53706 (United States); Geller, Aaron M. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Rd, Evanston, IL 60208 (United States); Sills, Alison [Department of Physics and Astronomy, McMaster University, 1280 Main St. W, Hamilton, ON L8S 4M1 (Canada); Leigh, Nathan [Department of Physics, University of Alberta, CCIS 4-183, Edmonton, AB T6G 2E1 (Canada); Knigge, Christian, E-mail: gosnell@astro.wisc.edu [School of Physics and Astronomy, University of Southampton, Highfield, Southampton, SO17 IBJ (United Kingdom)

    2014-03-01

    Several possible formation pathways for blue straggler stars have been developed recently, but no one pathway has yet been observationally confirmed for a specific blue straggler. Here we report the first findings from a Hubble Space Telescope Advanced Camera for Surveys/Solar Blind Channel far-UV photometric program to search for white dwarf companions to blue straggler stars. We find three hot and young white dwarf companions to blue straggler stars in the 7 Gyr open cluster NGC 188, indicating that mass transfer in these systems ended less than 300 Myr ago. These companions are direct and secure observational evidence that these blue straggler stars were formed through mass transfer in binary stars. Their existence in a well-studied cluster environment allows for observational constraints of both the current binary system and the progenitor binary system, mapping the entire mass transfer history.

  4. Eosin Y as a Direct Hydrogen Atom Transfer Photocatalyst for the Functionalization of C-H Bonds.

    Science.gov (United States)

    Fan, Xuan-Zi; Rong, Jia-Wei; Wu, Hao-Lin; Zhou, Quan; Deng, Hong-Ping; Tan, Jin Da; Xue, Cheng-Wen; Wu, Li-Zhu; Tao, Hai-Rong; Wu, Jie

    2018-05-02

    Eosin Y, a well-known economical alternative to metal catalysts in visible-light-driven single-electron transfer-based organic transformations, can behave as an effective direct hydrogen atom transfer catalyst for C-H activation. Using the alkylation of C-H bonds with electron-deficient alkenes as a model study revealed an extremely broad substrate scope, enabling easy access to a variety of important synthons. This eosin Y-based photocatalytic hydrogen atom transfer strategy is promising for diverse functionalization of a wide range of native C-H bonds in a green and sustainable manner. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Hierarchical meso/macro-porous carbon fabricated from dual MgO templates for direct electron transfer enzymatic electrodes

    Science.gov (United States)

    Funabashi, Hiroto; Takeuchi, Satoshi; Tsujimura, Seiya

    2017-03-01

    We designed a three-dimensional (3D) hierarchical pore structure to improve the current production efficiency and stability of direct electron transfer-type biocathodes. The 3D hierarchical electrode structure was fabricated using a MgO-templated porous carbon framework produced from two MgO templates with sizes of 40 and 150 nm. The results revealed that the optimal pore composition for a bilirubin oxidase-catalysed oxygen reduction cathode was a mixture of 33% macropores and 67% mesopores (MgOC33). The macropores improve mass transfer inside the carbon material, and the mesopores improve the electron transfer efficiency of the enzyme by surrounding the enzyme with carbon.

  6. The pollen complex from postglacial sediments of the Laptev Sea as a bioindicator

    Science.gov (United States)

    Naidina, O. D.

    2014-05-01

    The first results of comparison of palynological analysis (pollen of terrestrial plants), SEM analysis of pollen morphology, and radiocarbon age dating (AMS14C) of sediments of the eastern shelf of the Laptev Sea show that the diverse taxonomic composition of pollen spectra provides an integrated idea of the vegetation and climate of the region over 11.2 calendar kiloyears. It is found that phases of the tree and shrub vegetation development (maxima of pollen of Betula sect. Nanae and Pinus s/g Haploxylon) correspond to the warm epochs in the Holocene. It is obvious that birch phytocoenoses first settled in the southern tundra subzone with increasing temperature, and then coniferous communities of forest tundra. An occurrence of pollen of shrubby birches (Nanae) suggests compliance of permafrost landscapes with cold climate conditions, i.e., with an annual average temperature of -2°C and amount of precipitation of less than 500 mm. Owing to a progressive increase in summer temperatures, dwarf cedar and pine communities advanced toward the seashore. The SEM analysis results show that a significant proportion of regional coniferous pollen belongs to representatives of Pinus pumila (Pall.) and P. sylvestris L. In addition, the SEM study of the exine of Pinus sylvestris L. and P. pumila (Pall.) Regel pollen grains confirmed polymorphism in coniferous pollen. According to the inverse relationship between climate and vegetation, frequent climate fluctuations that are typical of progressive and differential postglacial transgression were revealed. An increase in arboreal pollen transfer onto the shelf later than 9.1 cal. ka coincides with the time of forest boundary migration to the north due to the warming of the Earth's climate. At that time, the tundra vegetation was replaced by forest-tundra vegetation, the maximum stage of sea transgression began, and there appeared a trend of increasing temperature and moisture.

  7. An orange fluorescent protein tagging system for real-time pollen tracking.

    Science.gov (United States)

    Rice, J Hollis; Millwood, Reginald J; Mundell, Richard E; Chambers, Orlando D; Abercrombie, Laura L; Davies, H Maelor; Stewart, C Neal

    2013-09-27

    Monitoring gene flow could be important for future transgenic crops, such as those producing plant-made-pharmaceuticals (PMPs) in open field production. A Nicotiana hybrid (Nicotiana. tabacum × Nicotiana glauca) shows limited male fertility and could be used as a bioconfined PMP platform. Effective assessment of gene flow from these plants is augmented with methods that utilize fluorescent proteins for transgenic pollen identification. We report the generation of a pollen tagging system utilizing an orange fluorescent protein to monitor pollen flow and as a visual assessment of transgene zygosity of the parent plant. This system was created to generate a tagged Nicotiana hybrid that could be used for the incidence of gene flow. Nicotiana tabacum 'TN 90' and Nicotiana glauca were successfully transformed via Agrobacterium tumefaciens to express the orange fluorescent protein gene, tdTomato-ER, in pollen and a green fluorescent protein gene, mgfp5-er, was expressed in vegetative structures of the plant. Hybrids were created that utilized the fluorescent proteins as a research tool for monitoring pollen movement and gene flow. Manual greenhouse crosses were used to assess hybrid sexual compatibility with N. tabacum, resulting in seed formation from hybrid pollination in 2% of crosses, which yielded non-viable seed. Pollen transfer to the hybrid formed seed in 19% of crosses and 10 out of 12 viable progeny showed GFP expression. The orange fluorescent protein is visible when expressed in the pollen of N. glauca, N. tabacum, and the Nicotiana hybrid, although hybrid pollen did not appear as bright as the parent lines. The hybrid plants, which show limited ability to outcross, could provide bioconfinement with the benefit of detectable pollen using this system. Fluorescent protein-tagging could be a valuable tool for breeding and in vivo ecological monitoring.

  8. Direct effects of ionizing radiation on integral membrane proteins. Noncovalent energy transfer requires specific interpeptide interactions

    International Nuclear Information System (INIS)

    Jhun, E.; Jhun, B.H.; Jones, L.R.; Jung, C.Y.

    1991-01-01

    The 12 transmembrane alpha helices (TMHs) of human erythrocyte glucose transporter were individually cut by pepsin digestion as membrane-bound 2.5-3.5-kDa peptide fragments. Radiation-induced chemical degradation of these fragments showed an average target size of 34 kDa. This is 10-12 x larger than the average size of an individual TMH, demonstrating that a significant energy transfer occurs among these TMHs in the absence of covalent linkage. Heating this TMH preparation at 100 degree C for 15 min reduced the target size to 5 kDa or less, suggesting that the noncovalent energy transfer requires specific helix-helix interactions. Purified phospholamban, a small (6-kDa) integral membrane protein containing a single TMH, formed a pentameric assembly in sodium dodecyl sulfate. The chemical degradation target size of this phospholamban pentamer was 5-6 kDa, illustrating that not all integral membrane protein assemblies permit intersubunit energy transfer. These findings together with other published observations suggest strongly that significant noncovalent energy transfer can occur within the tertiary and quaternary structure of membrane proteins and that as yet undefined proper molecular interactions are required for such covalent energy transfer. Our results with pepsin-digested glucose transporter also illustrate the importance of the interhelical interaction as a predominating force in maintaining the tertiary structure of a transmembrane protein

  9. A tentative assessment of cesium 137 direct and indirect transfer rates in a simplified fresh water food chain

    International Nuclear Information System (INIS)

    Foulquier, Luc; Lambrechts, Alain.

    1982-08-01

    A comparison was made of the direct transfer of cesium from water to carps and the indirect transfer via the food. In a first experiment on chronic contamination of carps by water, the kinetics and distribution of cesium in the organs of the carps were studied. Equilibrium was not reached on the 56th day, 4% of the initial water activity had been retained by the carps and the concentration factor was below 10. The highest specific activities were found in the transit organs. In a second experiment, the water activity varied by alternating contamination and decontamination. A fluctuating equilibrium was reached on the 22nd day. The concentration factor was of the same order of magnitude than in the previous experiment. Indirect contamination of fish by ingestion of contaminated daphnids was studied in a third experiment. Cesium levels in carps increased with the cumulated activities in meals, and the uptake rate in fish was 4%. Both decorporation and biological half-lives (30-40 days) were independent of the contamination routes. The respective significance of the transfer pathways is discussed taking into account the biomass pyramids to be found in the nature. It is estimated that in a cesium environment, 70% of the carp activity should come from the diet and 30% from the water. The concentration factor would then be 75 instead of 22 when only direct transfer of cesium from water to fish is considered [fr

  10. Structure-function insights into direct lipid transfer between membranes by Mmm1-Mdm12 of ERMES.

    Science.gov (United States)

    Kawano, Shin; Tamura, Yasushi; Kojima, Rieko; Bala, Siqin; Asai, Eri; Michel, Agnès H; Kornmann, Benoît; Riezman, Isabelle; Riezman, Howard; Sakae, Yoshitake; Okamoto, Yuko; Endo, Toshiya

    2018-03-05

    The endoplasmic reticulum (ER)-mitochondrial encounter structure (ERMES) physically links the membranes of the ER and mitochondria in yeast. Although the ER and mitochondria cooperate to synthesize glycerophospholipids, whether ERMES directly facilitates the lipid exchange between the two organelles remains controversial. Here, we compared the x-ray structures of an ERMES subunit Mdm12 from Kluyveromyces lactis with that of Mdm12 from Saccharomyces cerevisiae and found that both Mdm12 proteins possess a hydrophobic pocket for phospholipid binding. However in vitro lipid transfer assays showed that Mdm12 alone or an Mmm1 (another ERMES subunit) fusion protein exhibited only a weak lipid transfer activity between liposomes. In contrast, Mdm12 in a complex with Mmm1 mediated efficient lipid transfer between liposomes. Mutations in Mmm1 or Mdm12 impaired the lipid transfer activities of the Mdm12-Mmm1 complex and furthermore caused defective phosphatidylserine transport from the ER to mitochondrial membranes via ERMES in vitro. Therefore, the Mmm1-Mdm12 complex functions as a minimal unit that mediates lipid transfer between membranes. © 2018 Kawano et al.

  11. Application of the direct simulation Monte Carlo method to nanoscale heat transfer between a soot particle and the surrounding gas

    International Nuclear Information System (INIS)

    Yang, M.; Liu, F.; Smallwood, G.J.

    2004-01-01

    Laser-Induced Incandescence (LII) technique has been widely used to measure soot volume fraction and primary particle size in flames and engine exhaust. Currently there is lack of quantitative understanding of the shielding effect of aggregated soot particles on its conduction heat loss rate to the surrounding gas. The conventional approach for this problem would be the application of the Monte Carlo (MC) method. This method is based on simulation of the trajectories of individual molecules and calculation of the heat transfer at each of the molecule/molecule collisions and the molecule/particle collisions. As the first step toward calculating the heat transfer between a soot aggregate and the surrounding gas, the Direct Simulation Monte Carlo (DSMC) method was used in this study to calculate the heat transfer rate between a single spherical aerosol particle and its cooler surrounding gas under different conditions of temperature, pressure, and the accommodation coefficient. A well-defined and simple hard sphere model was adopted to describe molecule/molecule elastic collisions. A combination of the specular reflection and completely diffuse reflection model was used to consider molecule/particle collisions. The results obtained by DSMC are in good agreement with the known analytical solution of heat transfer rate for an isolated, motionless sphere in the free-molecular regime. Further the DSMC method was applied to calculate the heat transfer in the transition regime. Our present DSMC results agree very well with published DSMC data. (author)

  12. A research proposal for investigating the effect of foreign direct investments on technology transfer in the Arabian Gulf (GCC)

    Science.gov (United States)

    Tahat, Kaher; Whelan, Susan

    2015-02-01

    In terms of hosting countries perspectives, Foreign Direct Investments (FDI) could have a positive effect on its developing economy, by transferring, both: resources of finance in addition to the international technology (ITT) (Choi, 1997). Multinational companies (MNC) are engaging in the transferring of the new technology, internally as well as licensing older one; they create "Spillover" (Knowledge) for facilitating the transfer of ITT in line with geographical location, period of investment, and the type of industry. Furthermore, the effect of these spillovers depends on the level of transferring this knowledge based on FDI attraction policies of the host country (Huang, 2009). Considering the Arabian Gulf council countries (GCC) as "FDI- rich hosting countries", who are not seeking for financial resources, i.e., they already have a huge financial capacity for funding their different projects, even though FDI has been powerfully presented in GCC . They saw noticeable increases in FDI inflows beginning in 2002, (www.unctad.org.fdistatistics). Therefore by assumption, FDI inflows to GCC could positively affect their economic growth through transferring the advanced technology, in order to build up their level of technology (productivity growth) as well as their economic diversification strategy. If so how this Knowledge could be diffused and measured in order to maximize its benefit and enhancing the productivity growth, and what is the current status of (GCC).

  13. Direct Aldehyde C-H Arylation and Alkylation via the Combination of Nickel, Hydrogen Atom Transfer, and Photoredox Catalysis.

    Science.gov (United States)

    Zhang, Xiaheng; MacMillan, David W C

    2017-08-23

    A mechanism that enables direct aldehyde C-H functionalization has been achieved via the synergistic merger of photoredox, nickel, and hydrogen atom transfer catalysis. This mild, operationally simple protocol transforms a wide variety of commercially available aldehydes, along with aryl or alkyl bromides, into the corresponding ketones in excellent yield. This C-H abstraction coupling technology has been successfully applied to the expedient synthesis of the medicinal agent haloperidol.

  14. CFD simulation of direct contact condensation with ANSYS CFX using surface renewal theory based heat transfer coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Wanninger, Andreas; Ceuca, Sabin Cristian; Macian-Juan, Rafael [Technische Univ. Muenchen, Garching (Germany). Dept. of Nuclear Engineering

    2013-07-01

    Different approaches for the calculation of Direct Contact Condensation (DCC) using Heat Transfer Coefficients (HTC) based on the Surface Renewal Theory (SRT) are tested using the CFD simulation tool ANSYS CFX. The present work constitutes a preliminary study of the flow patterns and conditions observed using different HTC models. A complex 3D flow pattern will be observed in the CFD simulations as well as a strong coupling between the condensation rate and the two-phase flow dynamics. (orig.)

  15. Complementary Strategies for Directed C(sp3 )-H Functionalization: A Comparison of Transition-Metal-Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer.

    Science.gov (United States)

    Chu, John C K; Rovis, Tomislav

    2018-01-02

    The functionalization of C(sp 3 )-H bonds streamlines chemical synthesis by allowing the use of simple molecules and providing novel synthetic disconnections. Intensive recent efforts in the development of new reactions based on C-H functionalization have led to its wider adoption across a range of research areas. This Review discusses the strengths and weaknesses of three main approaches: transition-metal-catalyzed C-H activation, 1,n-hydrogen atom transfer, and transition-metal-catalyzed carbene/nitrene transfer, for the directed functionalization of unactivated C(sp 3 )-H bonds. For each strategy, the scope, the reactivity of different C-H bonds, the position of the reacting C-H bonds relative to the directing group, and stereochemical outcomes are illustrated with examples in the literature. The aim of this Review is to provide guidance for the use of C-H functionalization reactions and inspire future research in this area. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Pollen-Associated Microbiome Correlates with Pollution Parameters and the Allergenicity of Pollen.

    Directory of Open Access Journals (Sweden)

    Andrea Obersteiner

    Full Text Available Pollen allergies have been rapidly increasing over the last decades. Many allergenic proteins and non-allergenic adjuvant compounds of pollen are involved in the plant defense against environmental or microbial stress. The first aim of this study was to analyze and compare the colonizing microbes on allergenic pollen. The second aim was to investigate detectable correlations between pollen microbiota and parameters of air pollution or pollen allergenicity. To reach these aims, bacterial and fungal DNA was isolated from pollen samples of timothy grass (Phleum pratense, n = 20 and birch trees (Betula pendula, n = 55. With this isolated DNA, a terminal restriction fragment length polymorphism analysis was performed. One result was that the microbial diversity on birch tree and timothy grass pollen samples (Shannon/Simpson diversity indices was partly significantly correlated to allergenicity parameters (Bet v 1/Phl p 5, pollen-associated lipid mediators. Furthermore, the microbial diversity on birch pollen samples was correlated to on-site air pollution (nitrogen dioxide (NO2, ammonia (NH3, and ozone (O3. What is more, a significant negative correlation was observed between the microbial diversity on birch pollen and the measured NO2 concentrations on the corresponding trees. Our results showed that the microbial composition of pollen was correlated to environmental exposure parameters alongside with a differential expression of allergen and pollen-associated lipid mediators. This might translate into altered allergenicity of pollen due to environmental and microbial stress.

  17. Direct electron transfer of hemoglobin in a CdS nanorods and Nafion composite film on carbon ionic liquid electrode

    International Nuclear Information System (INIS)

    Sun Wei; Wang Dandan; Li Guicun; Zhai Ziqin; Zhao Ruijun; Jiao Kui

    2008-01-01

    In this paper the direct electron transfer of hemoglobin (Hb) was carefully investigated by using a room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF 6 ) modified carbon paste electrode (CILE) as the basal working electrode. Hb was immobilized on the surface of CILE with the nanocomposite film composed of Nafion and CdS nanorods by a step-by-step method. UV-vis and FT-IR spectra showed that Hb in the composite film remained its native structure. The direct electrochemical behaviors of Hb in the composite film were further studied in a pH 7.0 phosphate buffer solution (PBS). A pair of well-defined and quasi-reversible cyclic voltammetric peaks of Hb was obtained with the formal potential (E 0 ') at -0.295 V (vs. SCE), which was the characteristic of heme Fe(III)/Fe(II) redox couples. The direct electrochemistry of Hb was achieved on the modified electrode and the apparent heterogeneous electron transfer rate constant (k s ) was calculated to be 0.291 s -1 . The formal potentials of Hb Fe(III)/Fe(II) couple shifted negatively with the increase of buffer pH and a slope value of -45.1 mV/pH was got, which indicated that one electron transfer accompanied with one proton transportation. The fabricated Hb sensor showed good electrocatalytic manner to the reduction of trichloroacetic acid (TCA)

  18. Directed Energy Transfer in Films of CdSe Quantum Dots: Beyond the Point Dipole Approximation

    DEFF Research Database (Denmark)

    Zheng, Kaibo; Zídek, Karel; Abdellah, Mohamed

    2014-01-01

    Understanding of Förster resonance energy transfer (FRET) in thin films composed of quantum dots (QDs) is of fundamental and technological significance in optimal design of QD based optoelectronic devices. The separation between QDs in the densely packed films is usually smaller than the size of ...

  19. Potential for direct interspecies electron transfer in methanogenic wastewater digester aggregates

    DEFF Research Database (Denmark)

    Morita, Masahiko; Malvankar, Nikhil S; Franks, Ashley E

    2011-01-01

    Mechanisms for electron transfer within microbial aggregates derived from an upflow anaerobic sludge blanket reactor converting brewery waste to methane were investigated in order to better understand the function of methanogenic consortia. The aggregates were electrically conductive, with conduc...... for electron exchange in some methanogenic systems....

  20. Direct visualization of efficient energy transfer in single oligo(p-phenylene vinylene) vesicles

    NARCIS (Netherlands)

    Hoeben, F.J.M.; Shklyarevskiy, I.O.; Pouderoijen, M.J.; Engelkamp, H.; Schenning, A.P.H.J.; Christianen, P.C.M.; Maan, J.C.; Meijer, E.W.

    2006-01-01

    Monitoring self-assembled objects: Optical studies and scanning confocal microscopy have been used to monitor intermolecular energy transfer (ENT) in mixed vesicles of donor/acceptor oligo(p-phenylene vinylene)s (OPVs) in water (see picture) over time. This probing of the ongoing exchange process

  1. Direct transfer of metallic photonic structures onto end facets of optical fibers

    Science.gov (United States)

    Zhang, Xinping; Liu, Feifei; Lin, Yuanhai

    2016-07-01

    We present a flexible approach to transfer metallic photonic crystals (MPCs) onto end facets of optical fibers. The MPCs were initially fabricated on a glass substrate with a spacer layer of indium tin oxide (ITO), which was used as a buffer layer in the transferring process. The fiber ends were firstly welded on the top surface of the MPCs by a drop of polymer solution after the solvent evaporated. The ITO layer was then etched by hydrochloric acid (HCl), so that the MPCs got off the substrate and were transferred to the fiber ends. Alternatively, the MPCs may be also etched off the substrate first by immersing the sample in HCl. The ultra-thin MPC sheet consisting of gold nanolines interlaced with photoresist gratings was then transferred to cap the fiber ends. In the later approach, we can choose which side of the MPCs to be used as the contact with the fiber facet. Such methods enabled convenient nanostructuring on optical fiber tips and achieving miniaturized MPC devices with compact integration, extending significantly applications of MPCs. In particular, the fabrications presented in this manuscript enrich the lab-on-fiber engineering techniques and the resultant devices have potential applications in remote sensing and detection systems.

  2. Direct transfer of metallic photonic structures onto end facets of optical fibers

    Directory of Open Access Journals (Sweden)

    Xinping Zhang

    2016-07-01

    Full Text Available We present a flexible approach to transfer metallic photonic crystals (MPCs onto end facets of optical fibers. The MPCs were initially fabricated on a glass substrate with a spacer layer of indium tin oxide (ITO, which was used as a buffer layer in the transferring process. The fiber ends were firstly welded on the top surface of the MPCs by a drop of polymer solution after the solvent evaporated. The ITO layer was then etched by hydrochloric acid (HCl, so that the MPCs got off the substrate and were transferred to the fiber ends. Alternatively, the MPCs may be also etched off the substrate first by immersing the sample in HCl. The ultra-thin MPC sheet consisting of gold nanolines interlaced with photoresist gratings was then transferred to cap the fiber ends. In the later approach, we can choose which side of the MPCs to be used as the contact with the fiber facet. Such methods enabled convenient nanostructuring on optical fiber tips and achieving miniaturized MPC devices with compact integration, extending significantly applications of MPCs. In particular, the fabrications presented in this manuscript enrich the lab-on-fiber engineering techniques and the resultant devices have potential applications in remote sensing and detection systems.

  3. Seasonal and Spatial Variations of Indoor Pollen in a Hospital

    Directory of Open Access Journals (Sweden)

    Santiago Fernández-Rodríguez

    2009-12-01

    Full Text Available The airborne indoor pollen in a hospital of Badajoz (Spain was monitored over two years using a personal Burkard sampler. The air was sampled in four places indoors—one closed room and one open ward on each of the ground and the third floors—and one place outdoors at the entrance to the hospital. The results were compared with data from a continuous volumetric sampler. While 32 pollen types were identified, nearly 75% of the total counts were represented by just five of them. These were: Quercus, Cupressaceae, Poaceae, Olea, and Plantago. The average indoor concentration was 25.2 grains/m3, and the average indoor/outdoor ratio was 0.27. A strong seasonal pattern was found, with the highest levels in spring and winter, and the indoor concentrations were correlated with the outdoor one. Indoor air movement led to great homogeneity in the airborne pollen presence: the indoor results were not influenced by whether or not the room was isolated, the floor level, or the number of people in or transiting the site during sampling. The presence of ornamental vegetation in the area surrounding the building affected the indoor counts directly as sources of the pollen.

  4. Elucidating the design principles of photosynthetic electron-transfer proteins by site-directed spin labeling EPR spectroscopy.

    Science.gov (United States)

    Ishara Silva, K; Jagannathan, Bharat; Golbeck, John H; Lakshmi, K V

    2016-05-01

    Site-directed spin labeling electron paramagnetic resonance (SDSL EPR) spectroscopy is a powerful tool to determine solvent accessibility, side-chain dynamics, and inter-spin distances at specific sites in biological macromolecules. This information provides important insights into the structure and dynamics of both natural and designed proteins and protein complexes. Here, we discuss the application of SDSL EPR spectroscopy in probing the charge-transfer cofactors in photosynthetic reaction centers (RC) such as photosystem I (PSI) and the bacterial reaction center (bRC). Photosynthetic RCs are large multi-subunit proteins (molecular weight≥300 kDa) that perform light-driven charge transfer reactions in photosynthesis. These reactions are carried out by cofactors that are paramagnetic in one of their oxidation states. This renders the RCs unsuitable for conventional nuclear magnetic resonance spectroscopy investigations. However, the presence of native paramagnetic centers and the ability to covalently attach site-directed spin labels in RCs makes them ideally suited for the application of SDSL EPR spectroscopy. The paramagnetic centers serve as probes of conformational changes, dynamics of subunit assembly, and the relative motion of cofactors and peptide subunits. In this review, we describe novel applications of SDSL EPR spectroscopy for elucidating the effects of local structure and dynamics on the electron-transfer cofactors of photosynthetic RCs. Because SDSL EPR Spectroscopy is uniquely suited to provide dynamic information on protein motion, it is a particularly useful method in the engineering and analysis of designed electron transfer proteins and protein networks. This article is part of a Special Issue entitled Biodesign for Bioenergetics--the design and engineering of electronic transfer cofactors, proteins and protein networks, edited by Ronald L. Koder and J.L. Ross Anderson. Copyright © 2016. Published by Elsevier B.V.

  5. Task partitioning in a robot swarm: object retrieval as a sequence of subtasks with direct object transfer.

    Science.gov (United States)

    Pini, Giovanni; Brutschy, Arne; Scheidler, Alexander; Dorigo, Marco; Birattari, Mauro

    2014-01-01

    We study task partitioning in the context of swarm robotics. Task partitioning is the decomposition of a task into subtasks that can be tackled by different workers. We focus on the case in which a task is partitioned into a sequence of subtasks that must be executed in a certain order. This implies that the subtasks must interface with each other, and that the output of a subtask is used as input for the subtask that follows. A distinction can be made between task partitioning with direct transfer and with indirect transfer. We focus our study on the first case: The output of a subtask is directly transferred from an individual working on that subtask to an individual working on the subtask that follows. As a test bed for our study, we use a swarm of robots performing foraging. The robots have to harvest objects from a source, situated in an unknown location, and transport them to a home location. When a robot finds the source, it memorizes its position and uses dead reckoning to return there. Dead reckoning is appealing in robotics, since it is a cheap localization method and it does not require any additional external infrastructure. However, dead reckoning leads to errors that grow in time if not corrected periodically. We compare a foraging strategy that does not make use of task partitioning with one that does. We show that cooperation through task partitioning can be used to limit the effect of dead reckoning errors. This results in improved capability of locating the object source and in increased performance of the swarm. We use the implemented system as a test bed to study benefits and costs of task partitioning with direct transfer. We implement the system with real robots, demonstrating the feasibility of our approach in a foraging scenario.

  6. Fabrication of Ultrasensitive Field-Effect Transistor DNA Biosensors by a Directional Transfer Technique Based on CVD-Grown Graphene.

    Science.gov (United States)

    Zheng, Chao; Huang, Le; Zhang, Hong; Sun, Zhongyue; Zhang, Zhiyong; Zhang, Guo-Jun

    2015-08-12

    Most graphene field-effect transistor (G-FET) biosensors are fabricated through a routine process, in which graphene is transferred onto a Si/SiO2 substrate and then devices are subsequently produced by micromanufacture processes. However, such a fabrication approach can introduce contamination onto the graphene surface during the lithographic process, resulting in interference for the subsequent biosensing. In this work, we have developed a novel directional transfer technique to fabricate G-FET biosensors based on chemical-vapor-deposition- (CVD-) grown single-layer graphene (SLG) and applied this biosensor for the sensitive detection of DNA. A FET device with six individual array sensors was first fabricated, and SLG obtained by the CVD-growth method was transferred onto the sensor surface in a directional manner. Afterward, peptide nucleic acid (PNA) was covalently immobilized on the graphene surface, and DNA detection was realized by applying specific target DNA to the PNA-functionalized G-FET biosensor. The developed G-FET biosensor was able to detect target DNA at concentrations as low as 10 fM, which is 1 order of magnitude lower than those reported in a previous work. In addition, the biosensor was capable of distinguishing the complementary DNA from one-base-mismatched DNA and noncomplementary DNA. The directional transfer technique for the fabrication of G-FET biosensors is simple, and the as-constructed G-FET DNA biosensor shows ultrasensitivity and high specificity, indicating its potential application in disease diagnostics as a point-of-care tool.

  7. Heat and mass transfer effects in a direct methanol fuel cell: A 1D model

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, V.B.; Falcao, D.S.; Pinto, A.M.F.R. [Centro de Estudos de Fenomenos de Transporte, Departamento de Eng. Quimica, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Rangel, C.M. [INETI - Unidade de Electroquimica e Materiais, Paco do Lumiar, 22,1649-038 (Portugal)

    2008-07-15

    Models are a fundamental tool for the design process of fuel cells and fuel cell systems. In this work, a steady-state, one-dimensional model accounting for coupled heat and mass transfer, along with the electrochemical reactions occurring in the DMFC, is presented. The model output is the temperature profile through the cell and the water balance and methanol crossover between the anode and the cathode. The model predicts the correct trends for the influence of current density and methanol feed concentration on both methanol and water crossover. The model estimates the net water transfer coefficient through the membrane, {alpha}, a very important parameter to describe water management in the DMFC. Suitable operating ranges can be set up for different MEA structures maintaining the crossover of methanol and water within acceptable levels. The model is rapidly implemented and is therefore suitable for inclusion in real-time system level DMFC calculations. (author)

  8. Direct Observation of Molecular Preorganization for Chirality Transfer on a Catalyst Surface

    DEFF Research Database (Denmark)

    Demers-Carpentier, Vincent; Goubert,, Guillaume; Masini, Federico

    2011-01-01

    The chemisorption of specific optically active compounds on metal surfaces can create catalytically active chirality transfer sites. However, the mechanism through which these sites bias the stereoselectivity of reactions (typically hydrogenations) is generally assumed to be so complex that conti......The chemisorption of specific optically active compounds on metal surfaces can create catalytically active chirality transfer sites. However, the mechanism through which these sites bias the stereoselectivity of reactions (typically hydrogenations) is generally assumed to be so complex...... functional theory calculations reveals the stereodirecting forces governing preorganization into precise chiral modifier-substrate bimolecular surface complexes. The study shows that the chiral modifier induces prochiral switching on the surface and that different prochiral ratios prevail at different...

  9. Interplay between Dephasing and Geometry and Directed Heat Flow in Exciton Transfer Complexes

    OpenAIRE

    Dubi, Yonatan

    2015-01-01

    The striking efficiency of energy transfer in natural photosynthetic systems and the recent evidence of long-lived quantum coherence in biological light harvesting complexes has triggered much excitement, due to the evocative possibility that these systems - essential to practically all life on earth -- use quantum mechanical effects to achieve optimal functionality. A large body of theoretical work has addressed the role of local environments in determining the transport properties of excito...

  10. Bioaccumulation of 14C-Labeled Graphene in an Aquatic Food Chain through Direct Uptake or Trophic Transfer.

    Science.gov (United States)

    Dong, Shipeng; Xia, Tian; Yang, Yu; Lin, Sijie; Mao, Liang

    2018-01-16

    The growing applications of graphene materials warrant a careful evaluation of their environmental fate in aquatic food webs. Escherichia coli (Bacteria), Tetrahymena thermophila (protozoa), Daphnia magna (zooplankton), and Danio rerio (vertebrate) were used to build aquatic food chains to investigate the waterborne uptake and trophic transfer of 14 C-labeled graphene. Body burden factor (BBF) and trophic transfer factor (TTF) were analyzed for each organism and food chain to assess the bioaccumulation and biomagnification of graphene. The test organisms have high potential of accumulating graphene via direct uptake from culture medium with log-transformed BBF (log BBF) values of 3.66, 5.1, 3.9, and 1.62 for each organism, respectively. In the food chain from E. coli to T. thermophila, the calculated TTFs of 0.2 to 8.6 indicate the high trophic transfer potential in this aquatic food chain. However, the TTFs calculated for the food chain from T. thermophila to D. magna and from D. magna to D. rerio are much lower than 1, indicating that biomagnification was unlikely to occur in these food chains. Body burden measured for dietary uptake by T. thermophila, D. magna, and D. rerio are higher than that via waterborne exposure in a similar nominal concentration, respectively, indicating that trophic transfer is a nonnegligible route for the bioaccumulation of graphene in organisms.

  11. Boosting biomethane yield and production rate with graphene: The potential of direct interspecies electron transfer in anaerobic digestion.

    Science.gov (United States)

    Lin, Richen; Cheng, Jun; Zhang, Jiabei; Zhou, Junhu; Cen, Kefa; Murphy, Jerry D

    2017-09-01

    Interspecies electron transfer between bacteria and archaea plays a vital role in enhancing energy efficiency of anaerobic digestion (AD). Conductive carbon materials (i.e. graphene nanomaterial and activated charcoal) were assessed to enhance AD of ethanol (a key intermediate product after acidogenesis of algae). The addition of graphene (1.0g/L) resulted in the highest biomethane yield (695.0±9.1mL/g) and production rate (95.7±7.6mL/g/d), corresponding to an enhancement of 25.0% in biomethane yield and 19.5% in production rate. The ethanol degradation constant was accordingly improved by 29.1% in the presence of graphene. Microbial analyses revealed that electrogenic bacteria of Geobacter and Pseudomonas along with archaea Methanobacterium and Methanospirillum might participate in direct interspecies electron transfer (DIET). Theoretical calculations provided evidence that graphene-based DIET can sustained a much higher electron transfer flux than conventional hydrogen transfer. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Fragmentation and direct transfer reactions for 40Ar incident beam on 27Al target at 1760 MeV

    International Nuclear Information System (INIS)

    Cisse, Ousmane

    1985-01-01

    Peripheral collision studies performed with 40 Ar projectiles at 44 MeV/A and 27 Al target show that both fragmentation and transfer reactions can be discerned in this type of interaction. The experimental observation of fragments with masses charges and velocities close to those of the incident beam are the signature of transfer reactions and a detailed analysis of the energy spectra of such fragments has been carried out and interpreted in terms of a direct diffraction transfer model. On the other hand, for large mass transfer reactions, abrasion is the suitable mechanism. Inclusive fragment measurement together with the appropriate residual nuclei-fragment coincidence results then provides experimental data in good agreement with the theoretical predictions obtained from a participant spectator model. These investigations also indicate that the separation energies of the participant from the spectator nucleus, at least within the framework of the above model, can be interpreted in terms of a friction force which becomes more efficient as the projectile energy decreases. (author) [fr

  13. In Vitro Pollen Viability and Pollen Germination in Cherry Laurel (Prunus laurocerasus L.

    Directory of Open Access Journals (Sweden)

    Melekber Sulusoglu

    2014-01-01

    Full Text Available Pollen quality is important for growers and breeders. This study was carried out to determine in vitro pollen viability and pollen germination in seven genotypes of cherry laurel (Prunus laurocerasus L.. Two pollen viability tests, TTC (2,3,5-triphenyl tetrazolium chloride and IKI (iodine potassium iodide, were used. Pollen traits of genotypes were studied using an in vitro medium containing 0%, 5%, 10%, 15%, and 20% sucrose to determine the best sucrose concentrations for germination. In the second step, the germinated pollen was counted 1, 4, 6, 10, 12, 24, and 48 hours later until there was no further germination. The viability rates were different according to genotypes and tests used. The IKI and TTC staining tests and pollen germination had low correlation (r2 = 0.0614 and r2 = 0.0015, resp.. Painted pollen rate was higher and pollen was well-stained with IKI test and pollen viability estimated with TTC staining test was better than that estimated with the IKI staining test. 15% sucrose gave the best germination rates in most of the genotypes. Pollen germination rates were recorded periodically from one hour to 48 hours in 15% sucrose and the results showed that pollen germination rates increased after 6 hours of being placed in culture media.

  14. In vitro pollen viability and pollen germination in cherry laurel (Prunus laurocerasus L.).

    Science.gov (United States)

    Sulusoglu, Melekber; Cavusoglu, Aysun

    2014-01-01

    Pollen quality is important for growers and breeders. This study was carried out to determine in vitro pollen viability and pollen germination in seven genotypes of cherry laurel (Prunus laurocerasus L.). Two pollen viability tests, TTC (2,3,5-triphenyl tetrazolium chloride) and IKI (iodine potassium iodide), were used. Pollen traits of genotypes were studied using an in vitro medium containing 0%, 5%, 10%, 15%, and 20% sucrose to determine the best sucrose concentrations for germination. In the second step, the germinated pollen was counted 1, 4, 6, 10, 12, 24, and 48 hours later until there was no further germination. The viability rates were different according to genotypes and tests used. The IKI and TTC staining tests and pollen germination had low correlation (r(2) = 0.0614 and r(2) = 0.0015, resp.). Painted pollen rate was higher and pollen was well-stained with IKI test and pollen viability estimated with TTC staining test was better than that estimated with the IKI staining test. 15% sucrose gave the best germination rates in most of the genotypes. Pollen germination rates were recorded periodically from one hour to 48 hours in 15% sucrose and the results showed that pollen germination rates increased after 6 hours of being placed in culture media.

  15. Pollen Contents Of Commercial Honeys Of Opi, Nsukka, Enugu ...

    African Journals Online (AJOL)

    Pollen Contents Of Commercial Honeys Of Opi, Nsukka, Enugu State, Nigeria. ... Abstract. Pollen analyses of seven honey samples from Opi-Nsukka Mini market were evaluated for their pollen composition. The results ... HOW TO USE AJOL.

  16. Pollen diversity, viability and floral structure of some Musa genotypes

    African Journals Online (AJOL)

    Pollen diversity, viability and floral structure of some Musa genotypes. ... This experiment was designed to study the floral structure, pollen morphology and the potential pollen viability of five Musa genotypes obtained ... HOW TO USE AJOL.

  17. Continuum simulation of heat transfer and solidification behavior of AlSi10Mg in Direct Metal Laser Sintering Process

    Science.gov (United States)

    Ojha, Akash; Samantaray, Mihir; Nath Thatoi, Dhirendra; Sahoo, Seshadev

    2018-03-01

    Direct Metal Laser Sintering (DMLS) process is a laser based additive manufacturing process, which built complex structures from powder materials. Using high intensity laser beam, the process melts and fuse the powder particles makes dense structures. In this process, the laser beam in terms of heat flux strikes the powder bed and instantaneously melts and joins the powder particles. The partial solidification and temperature distribution on the powder bed endows a high cooling rate and rapid solidification which affects the microstructure of the build part. During the interaction of the laser beam with the powder bed, multiple modes of heat transfer takes place in this process, that make the process very complex. In the present research, a comprehensive heat transfer and solidification model of AlSi10Mg in direct metal laser sintering process has been developed on ANSYS 17.1.0 platform. The model helps to understand the flow phenomena, temperature distribution and densification mechanism on the powder bed. The numerical model takes into account the flow, heat transfer and solidification phenomena. Simulations were carried out for sintering of AlSi10Mg powders in the powder bed having dimension 3 mm × 1 mm × 0.08 mm. The solidification phenomena are incorporated by using enthalpy-porosity approach. The simulation results give the fundamental understanding of the densification of powder particles in DMLS process.

  18. Scalable High-Performance Ultraminiature Graphene Micro-Supercapacitors by a Hybrid Technique Combining Direct Writing and Controllable Microdroplet Transfer.

    Science.gov (United States)

    Shen, Daozhi; Zou, Guisheng; Liu, Lei; Zhao, Wenzheng; Wu, Aiping; Duley, Walter W; Zhou, Y Norman

    2018-02-14

    Miniaturization of energy storage devices can significantly decrease the overall size of electronic systems. However, this miniaturization is limited by the reduction of electrode dimensions and the reproducible transfer of small electrolyte drops. This paper reports first a simple scalable direct writing method for the production of ultraminiature microsupercapacitor (MSC) electrodes, based on femtosecond laser reduced graphene oxide (fsrGO) interlaced pads. These pads, separated by 2 μm spacing, are 100 μm long and 8 μm wide. A second stage involves the accurate transfer of an electrolyte microdroplet on top of each individual electrode, which can avoid any interference of the electrolyte with other electronic components. Abundant in-plane mesopores in fsrGO induced by a fs laser together with ultrashort interelectrode spacing enables MSCs to exhibit a high specific capacitance (6.3 mF cm -2 and 105 F cm -3 ) and ∼100% retention after 1000 cycles. An all graphene resistor-capacitor (RC) filter is also constructed by combining the MSC and a fsrGO resistor, which is confirmed to exhibit highly enhanced performance characteristics. This new hybrid technique combining fs laser direct writing and precise microdroplet transfer easily enables scalable production of ultraminiature MSCs, which is believed to be significant for practical application of micro-supercapacitor microelectronic systems.

  19. A small asparagine-rich protein required for S-allele-specific pollen rejection in Nicotiana.

    Science.gov (United States)

    McClure, B; Mou, B; Canevascini, S; Bernatzky, R

    1999-11-09

    Although S-locus RNases (S-RNases) determine the specificity of pollen rejection in self-incompatible (SI) solanaceous plants, they alone are not sufficient to cause S-allele-specific pollen rejection. To identify non-S-RNase sequences that are required for pollen rejection, a Nicotiana alata cDNA library was screened by differential hybridization. One clone, designated HT, hybridized strongly to RNA from N. alata styles but not to RNA from Nicotiana plumbaginifolia, a species known to lack one or more factors necessary for S-allele-specific pollen rejection. Sequence analysis revealed a 101-residue ORF including a putative secretion signal and an asparagine-rich domain near the C terminus. RNA blot analysis showed that the HT-transcript accumulates in the stigma and style before anthesis. The timing of HT-expression lags slightly behind S(C10)-RNase in SI N. alata S(C10)S(C10) and is well correlated with the onset of S-allele-specific pollen rejection in the style. An antisense-HT construct was prepared to test for a role in pollen rejection. Transformed (N. plumbaginifolia x SI N. alata S(C10)S(C10)) hybrids with reduced levels of HT-protein continued to express S(C10)-RNase but failed to reject S(C10)-pollen. Control hybrids expressing both S(C10)-RNase and HT-protein showed a normal S-allele-specific pollen rejection response. We conclude that HT-protein is directly implicated in pollen rejection.

  20. Pollen Sterility—A Promising Approach to Gene Confinement and Breeding for Genetically Modified Bioenergy Crops

    Directory of Open Access Journals (Sweden)

    Albert P. Kausch

    2012-10-01

    Full Text Available Advanced genetic and biotechnology tools will be required to realize the full potential of food and bioenergy crops. Given current regulatory concerns, many transgenic traits might never be deregulated for commercial release without a robust gene confinement strategy in place. The potential for transgene flow from genetically modified (GM crops is widely known. Pollen-mediated transfer is a major component of gene flow in flowering plants and therefore a potential avenue for the escape of transgenes from GM crops. One approach for preventing and/or mitigating transgene flow is the production of trait linked pollen sterility. To evaluate the feasibility of generating pollen sterility lines for gene confinement and breeding purposes we tested the utility of a promoter (Zm13Pro from a maize pollen-specific gene (Zm13 for driving expression of the reporter gene GUS and the cytotoxic gene barnase in transgenic rice (Oryza sativa ssp. Japonica cv. Nipponbare as a monocot proxy for bioenergy grasses. This study demonstrates that the Zm13 promoter can drive pollen-specific expression in stably transformed rice and may be useful for gametophytic transgene confinement and breeding strategies by pollen sterility in food and bioenergy crops.

  1. Dominance of Plasmonic Resonant Energy Transfer over Direct Electron Transfer in Substantially Enhanced Water Oxidation Activity of BiVO4 by Shape-Controlled Au Nanoparticles.

    Science.gov (United States)

    Lee, Mi Gyoung; Moon, Cheon Woo; Park, Hoonkee; Sohn, Woonbae; Kang, Sung Bum; Lee, Sanghan; Choi, Kyoung Jin; Jang, Ho Won

    2017-10-01

    The performance of plasmonic Au nanostructure/metal oxide heterointerface shows great promise in enhancing photoactivity, due to its ability to confine light to the small volume inside the semiconductor and modify the interfacial electronic band structure. While the shape control of Au nanoparticles (NPs) is crucial for moderate bandgap semiconductors, because plasmonic resonance by interband excitations overlaps above the absorption edge of semiconductors, its critical role in water splitting is still not fully understood. Here, first, the plasmonic effects of shape-controlled Au NPs on bismuth vanadate (BiVO 4 ) are studied, and a largely enhanced photoactivity of BiVO 4 is reported by introducing the octahedral Au NPs. The octahedral Au NP/BiVO 4 achieves 2.4 mA cm -2 at the 1.23 V versus reversible hydrogen electrode, which is the threefold enhancement compared to BiVO 4 . It is the highest value among the previously reported plasmonic Au NPs/BiVO 4 . Improved photoactivity is attributed to the localized surface plasmon resonance; direct electron transfer (DET), plasmonic resonant energy transfer (PRET). The PRET can be stressed over DET when considering the moderate bandgap semiconductor. Enhanced water oxidation induced by the shape-controlled Au NPs is applicable to moderate semiconductors, and shows a systematic study to explore new efficient plasmonic solar water splitting cells. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Effect of micro-scale wind on the measurement of airborne pollen concentrations using volumetric methods on a building rooftop

    Science.gov (United States)

    Miki, Kenji; Kawashima, Shigeto; Fujita, Toshio; Nakamura, Kimihito; Clot, Bernard

    2017-06-01

    Evaluating airborne pollen concentrations is important for the understanding of the spatiotemporal dispersion of pollen grains. Using two identical pollen monitors in parallel, we performed two experiments in order to study the influences of a) the physical characteristics (orientation) of the air inlet and b) the presence of obstacles in proximity to the monitors on airborne pollen concentration data. The first experiment consisted of an evaluation of airborne pollen concentrations using two different types of orifices; 1) a vertically oriented inlet and 2) a wind vane intake, both attached to the same type of automatic pollen sampler. The second experiment investigated the relationship between vertical wind speed and horizontal wind direction around an obstacle with the goal of studying the impact of micro-scale wind on pollen sampling efficiency. The results of the two experiments suggest that the wind path near an obstacle might be redirected in a vertical direction before or after the wind flows over the obstacle, which causes measurement errors of airborne pollen concentrations that are proportional to the vertical wind speed, especially when a vertically oriented inlet is used.

  3. Transient heat transfer in a directly-irradiated solar chemical reactor for the thermal dissociation of ZnO

    International Nuclear Information System (INIS)

    Mueller, R.; Lipinski, W.; Steinfeld, A.

    2008-01-01

    A numerical and experimental investigation is carried out in a solar thermochemical reactor for the thermal dissociation of ZnO at 2000 K using concentrated solar energy. The reactor consists of a cavity-receiver lined with ZnO particles and directly exposed to high-flux irradiation. A transient heat transfer model is formulated to link the rate of radiation, convection, and conduction heat transfer to the reaction kinetics. The radiosity and Monte Carlo methods are applied to obtain the distribution of net radiative fluxes at the internal surfaces of the reactor cavity and at the surface of the ZnO bed. Validation is accomplished in terms of the calculated and measured transient temperature profiles and chemical reaction rates

  4. Efficient Direct-Matching Rectenna Design for RF Power Transfer Applications

    Science.gov (United States)

    Keyrouz, Shady; Visser, Huib

    2013-12-01

    This paper presents the design, simulation, fabrication and measurements of a 50 ohm rectenna system. The paper investigates each part (in terms of input impedance) of the rectenna system starting from the antenna, followed by the matching network, to the rectifier. The system consists of an antenna, which captures the transmitted RF signal, connected to a rectifier which converts the AC captured signal into a DC power signal. For maximum power transfer, a matching network is designed between the rectifier and the antenna. At an input power level of -10 dBm, the system is able to achieve an RF/DC power conversion efficiency of 49.7%.

  5. Efficient Direct-Matching Rectenna Design for RF Power Transfer Applications

    International Nuclear Information System (INIS)

    Keyrouz, Shady; Visser, Huib

    2013-01-01

    This paper presents the design, simulation, fabrication and measurements of a 50 ohm rectenna system. The paper investigates each part (in terms of input impedance) of the rectenna system starting from the antenna, followed by the matching network, to the rectifier. The system consists of an antenna, which captures the transmitted RF signal, connected to a rectifier which converts the AC captured signal into a DC power signal. For maximum power transfer, a matching network is designed between the rectifier and the antenna. At an input power level of −10 dBm, the system is able to achieve an RF/DC power conversion efficiency of 49.7%

  6. Inferring Weighted Directed Association Networks from Multivariate Time Series with the Small-Shuffle Symbolic Transfer Entropy Spectrum Method

    Directory of Open Access Journals (Sweden)

    Yanzhu Hu

    2016-09-01

    Full Text Available Complex network methodology is very useful for complex system exploration. However, the relationships among variables in complex systems are usually not clear. Therefore, inferring association networks among variables from their observed data has been a popular research topic. We propose a method, named small-shuffle symbolic transfer entropy spectrum (SSSTES, for inferring association networks from multivariate time series. The method can solve four problems for inferring association networks, i.e., strong correlation identification, correlation quantification, direction identification and temporal relation identification. The method can be divided into four layers. The first layer is the so-called data layer. Data input and processing are the things to do in this layer. In the second layer, we symbolize the model data, original data and shuffled data, from the previous layer and calculate circularly transfer entropy with different time lags for each pair of time series variables. Thirdly, we compose transfer entropy spectrums for pairwise time series with the previous layer’s output, a list of transfer entropy matrix. We also identify the correlation level between variables in this layer. In the last layer, we build a weighted adjacency matrix, the value of each entry representing the correlation level between pairwise variables, and then get the weighted directed association network. Three sets of numerical simulated data from a linear system, a nonlinear system and a coupled Rossler system are used to show how the proposed approach works. Finally, we apply SSSTES to a real industrial system and get a better result than with two other methods.

  7. Positive effects of bio-nano Pd (0) toward direct electron transfer in Pseudomona putida and phenol biodegradation.

    Science.gov (United States)

    Niu, Zhuyu; Jia, Yating; Chen, Yuancai; Hu, Yongyou; Chen, Junfeng; Lv, Yuancai

    2018-06-08

    This study constructed a biological-inorganic hybrid system including Pseudomonas putida (P. putida) and bioreduced Pd (0) nanoparticles (NPs), and inspected the influence of bio-nano Pd (0) on the direct electron transfer and phenol biodegradation. Scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDX) showed that bio-nano Pd (0) (~10 nm) were evenly dispersed on the surface and in the periplasm of P. putida. With the incorporation of bio-nano Pd (0), the redox currents of bacteria in the cyclic voltammetry (CV) became higher and the oxidation current increased as the addition of lactate, while the highest increase rates of two electron transfer system (ETS) rates were 63.97% and 33.79%, respectively. These results indicated that bio-nano Pd (0) could directly promote the electron transfer of P. putida. In phenol biodegradation process, P. putida-Pd (0)- 2 showed the highest k (0.2992 h -1 ), μ m (0.035 h -1 ) and K i (714.29 mg/L) and the lowest apparent K s (76.39 mg/L). The results of kinetic analysis indicated that bio-nano Pd (0) markedly enhanced the biocatalytic efficiency, substrate affinity and the growth of cells compared to native P. putida. The positive effects of bio-nano Pd (0) to the electron transfer of P. putida would promote the biodegradation of phenol. Copyright © 2018 Elsevier Inc. All rights reserved.

  8. Weak Static and Extremely Low Frequency Magnetic Fields Affect In Vitro Pollen Germination

    Directory of Open Access Journals (Sweden)

    Lucietta Betti

    2011-01-01

    Full Text Available This study concerns the effects of a weak static magnetic field (MF at 10 μT oriented downward, combined with a 16-Hz sinusoidal MF (10 μT, on in vitro pollen germination of kiwifruit (Actinidia deliciosa. Extremely low frequency magnetic field (ELF-MF exposure was carried out by a signal generator unit connected to a copper wire solenoid, inside which samples where placed. Two different kinds of treatment were performed: direct and indirect. In the direct treatment, pollen samples were directly exposed during rehydration, germination, or both. In the indirect treatment, the pollen growth medium was prepared with water aliquots (at standard temperature of 20°C and pH = 6.74 that were exposed before use for 8 or 24 h. The main purpose of our research was to identify a biological marker (in vitro pollen germination in a stressing growth medium without Ca2+ susceptible to the effects of direct or indirect ELF-MF exposure. The working variable was the pollen germination rate, as detected blind after 3 h 30 min by an Axioplan microscope. A directionally consistent recovery of germination percentage was observed both for direct exposure (during germination and both rehydration and germination phases and water-mediated exposure (with water exposed for 24 h and immediately used. Our results suggest that the ELF-MF treatment might partially remove the inhibitory effect caused by the lack of Ca2+ in the culture medium, inducing a release of internal Ca2+ stored in the secretory vesicles of pollen plasma membrane. Although preliminary, findings seem to indicate the in vitro pollen performance as adequate to study the effects of ELF-MFs on living matter.

  9. Calculating the Motion and Direction of Flux Transfer Events with Cluster

    Science.gov (United States)

    Collado-Vega, Y. M.; Sibeck, D. G.

    2012-01-01

    For many years now, the interactions of the solar wind plasma with the Earth's magnetosphere has been one of the most important problems for Space Physics. It is very important that we understand these processes because the high-energy particles and also the solar wind energy that cross the magneto sphere could be responsible for serious damage to our technological systems. The solar wind is inherently a dynamic medium, and the particles interaction with the Earth's magnetosphere can be steady or unsteady. Unsteady interaction include transient processes like bursty magnetic reconnection. Flux Transfer Events (FTEs) are magnetopause signatures that usually occur during transient times of reconnection. They exhibit bipolar signatures in the normal component of the magnetic field. We use multi-point timing analysis to determine the orientation and motion of ux transfer events (FTEs) detected by the four Cluster spacecraft on the high-latitude dayside and flank magnetopause during 2002 and 2003. During these years, the distances between the Cluster spacecraft were greater than 1000 km, providing the tetrahedral configuration needed to select events and determine velocities. Each velocity and location will be examined in detail and compared to the velocities and locations determined by the predictions of the component and antiparallel reconnection models for event formation, orientation, motion, and acceleration for a wide range of spacecraft locations and solar wind conditions.

  10. Investigations of the Propagation of Plant Pollen by an Indicator Activation Method

    Energy Technology Data Exchange (ETDEWEB)

    Fendrik, I.; Glubrecht, H. [Technische Hochschule, Hanover (Germany)

    1967-10-15

    The study of the propagation of plant pollen is of special interest in ecology and plant breeding. Generally, radioactive labelling cannot be applied for this purpose since radioactive contamination of the materials under investigation cannot be tolerated. Instead, labelling can be performed by the use of an indicator element that has a high cross-section for neutron activation. This substance is introduced into the plant under consideration. The flying pollen is caught by polyethylene foils by means of electrostatic attraction. The foils with the pollen are irradiated in a nuclear reactor with a suitable flux of thermal neutrons. The labelled pollen grains can be detected and counted by autoradiography or by direct measurement. The method has proved satisfactory for pines and sugar beet. Indicator elements used for detection by neutron activation were manganese and dysprosium. (author)

  11. Pollen structure visualization using high-resolution laboratory-based hard X-ray tomography.

    Science.gov (United States)

    Li, Qiong; Gluch, Jürgen; Krüger, Peter; Gall, Martin; Neinhuis, Christoph; Zschech, Ehrenfried

    2016-10-14

    A laboratory-based X-ray microscope is used to investigate the 3D structure of unstained whole pollen grains. For the first time, high-resolution laboratory-based hard X-ray microscopy is applied to study pollen grains. Based on the efficient acquisition of statistically relevant information-rich images using Zernike phase contrast, both surface- and internal structures of pine pollen - including exine, intine and cellular structures - are clearly visualized. The specific volumes of these structures are calculated from the tomographic data. The systematic three-dimensional study of pollen grains provides morphological and structural information about taxonomic characters that are essential in palynology. Such studies have a direct impact on disciplines such as forestry, agriculture, horticulture, plant breeding and biodiversity. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Experimental studies of direct contact heat transfer in a slurry bubble column at high gas temperature of a helium–water–alumina system

    International Nuclear Information System (INIS)

    Abdulrahman, M.W.

    2015-01-01

    In this paper, the direct contact heat transfer is investigated experimentally for a helium gas at 90 °C injected through a slurry of water at 22 °C and alumina solid particles in a slurry bubble column reactor. This work examines the effects of superficial gas velocity, static liquid height, solid particles concentration and solid particle size, on the volumetric heat transfer coefficient and slurry temperature of the slurry bubble column reactor. These effects are formulated in forms of empirical equations. From the experimental work, it is found that the volumetric heat transfer coefficient and the slurry temperature increase by increasing the superficial gas velocity with a higher rate of increase at lower superficial gas velocity. In addition, the volumetric heat transfer coefficient and the slurry temperature decrease by increasing the static liquid height and/or the solid concentration at any given superficial gas velocity. Furthermore, it is found that the rate of decrease of the volumetric heat transfer coefficient with the solid concentration is approximately the same for different superficial gas velocities, and the decrease of the slurry temperature with the solid concentration is negligible. - Highlights: • Direct contact heat transfer is investigated experimentally in a slurry bubble column. • Empirical equation of direct contact heat transfer Nusselt number is formulated. • The volumetric heat transfer coefficient increases with superficial gas velocity. • The volumetric heat transfer coefficient decreases with the static liquid height. • The volumetric heat transfer coefficient decreases with the solid concentration.

  13. Direct self-assembling and patterning of semiconductor quantum dots on transferable elastomer layer

    Energy Technology Data Exchange (ETDEWEB)

    Coppola, Sara [Institute of Applied Sciences and Intelligent System- CNR, Via Campi Flegrei 34, Pozzuoli, 80078 (Italy); Vespini, Veronica, E-mail: v.vespini@isasi.cnr.it [Institute of Applied Sciences and Intelligent System- CNR, Via Campi Flegrei 34, Pozzuoli, 80078 (Italy); Olivieri, Federico [Institute of Applied Sciences and Intelligent System- CNR, Via Campi Flegrei 34, Pozzuoli, 80078 (Italy); University of Naples Federico II, Department of Chemical Materials and Production Engineering, Piazzale Tecchio 80, Naples 80125 (Italy); Nasti, Giuseppe; Todino, Michele; Mandracchia, Biagio; Pagliarulo, Vito; Ferraro, Pietro [Institute of Applied Sciences and Intelligent System- CNR, Via Campi Flegrei 34, Pozzuoli, 80078 (Italy)

    2017-03-31

    Highlights: • A quantum dots self-patterning on micrometrical polymeric array is proposed. • The effect of a quantum dots mix on the array is evaluated. • A PDMS membrane is exploited to transfer the pattern on it. - Abstract: Functionalization of thin and stretchable polymer layers by nano- and micro-patterning of nanoparticles is a very promising field of research that can lead to many different applications in biology and nanotechnology. In this work, we present a new procedure to self-assemble semiconductor quantum dots (QDs) nanoparticles by a simple fabrication process on a freestanding flexible PolyDiMethylSiloxane (PDMS) membrane. We used a Periodically Poled Lithium Niobate (PPLN) crystal to imprint a micrometrical pattern on the PDMS membrane that drives the QDs self-structuring on its surface. This process allows patterning QDs with different wavelength emissions in a single step in order to tune the overall emission spectrum of the composite, tuning the QDs mixing ratio.

  14. A Review of the Effects of Major Atmospheric Pollutants on Pollen Grains, Pollen Content, and Allergenicity

    Directory of Open Access Journals (Sweden)

    Hélène Sénéchal

    2015-01-01

    Full Text Available This review summarizes the available data related to the effects of air pollution on pollen grains from different plant species. Several studies carried out either on in situ harvested pollen or on pollen exposed in different places more or less polluted are presented and discussed. The different experimental procedures used to monitor the impact of pollution on pollen grains and on various produced external or internal subparticles are listed. Physicochemical and biological effects of artificial pollution (gaseous and particulate on pollen from different plants, in different laboratory conditions, are considered. The effects of polluted pollen grains, subparticles, and derived aeroallergens in animal models, in in vitro cell culture, on healthy human and allergic patients are described. Combined effects of atmospheric pollutants and pollen grains-derived biological material on allergic population are specifically discussed. Within the notion of “polluen,” some methodological biases are underlined and research tracks in this field are proposed.

  15. A Review of the Effects of Major Atmospheric Pollutants on Pollen Grains, Pollen Content, and Allergenicity

    Science.gov (United States)

    Sénéchal, Hélène; Visez, Nicolas; Charpin, Denis; Shahali, Youcef; Peltre, Gabriel; Biolley, Jean-Philippe; Lhuissier, Franck; Couderc, Rémy; Yamada, Ohri; Malrat-Domenge, Audrey; Pham-Thi, Nhân; Poncet, Pascal; Sutra, Jean-Pierre

    2015-01-01

    This review summarizes the available data related to the effects of air pollution on pollen grains from different plant species. Several studies carried out either on in situ harvested pollen or on pollen exposed in different places more or less polluted are presented and discussed. The different experimental procedures used to monitor the impact of pollution on pollen grains and on various produced external or internal subparticles are listed. Physicochemical and biological effects of artificial pollution (gaseous and particulate) on pollen from different plants, in different laboratory conditions, are considered. The effects of polluted pollen grains, subparticles, and derived aeroallergens in animal models, in in vitro cell culture, on healthy human and allergic patients are described. Combined effects of atmospheric pollutants and pollen grains-derived biological material on allergic population are specifically discussed. Within the notion of “polluen,” some methodological biases are underlined and research tracks in this field are proposed. PMID:26819967

  16. Catalytic carbene transfer allows the direct customization of cyclic purine dinucleotides.

    Science.gov (United States)

    Fei, Na; Häussinger, Daniel; Blümli, Seraina; Laventie, Benoît-Joseph; Bizzini, Lorenzo D; Zimmermann, Kaspar; Jenal, Urs; Gillingham, Dennis

    2014-08-11

    We describe a simple method for the direct modification of nucleobases in cyclic purine dinucleotides, important signalling molecules in both prokaryotes and eukaryotes. The method tolerates all members of the cyclic dinucleotide family and could be used to modulate their function or introduce useful side-chains such as fluorophores and photo-crosslinking groups.

  17. Interference between direct and indirect modes in two-nucleon transfer reactions with heavy ions

    International Nuclear Information System (INIS)

    Scott, D.K.; Harvey, B.G.; Hendrie, D.L.; Jahnke, U.; Kraus, L.; Maguire, C.F.; Mahoney, J.; Terrien, Y.; Yagi, K.; Glendenning, N.K.

    1975-01-01

    Direct and indirect transitions to the lowest 2 + collective states are shown to interfere constructively in the pickup reaction 122 Sn( 16 O, 18 O) 120 Sn at 104 MeV, and destructively in the inverse stripping reaction 120 Sn( 18 O, 16 O) 122 Sn at 99 MeV

  18. Pollen and spores of terrestrial plants

    Science.gov (United States)

    Bernhardt, Christopher E.; Willard, Debra A.; Shennan, Ian; Long, Antony J.; Horton, Benjamin P.

    2015-01-01

    Pollen and spores are valuable tools in reconstructing past sea level and climate because of their ubiquity, abundance, and durability as well as their reciprocity with source vegetation to environmental change (Cronin, 1999; Traverse, 2007; Willard and Bernhardt, 2011). Pollan is found in many sedimentary environments, from freshwater to saltwater, terrestrial to marine. It can be abundant in a minimal amount of sample material, for example half a gram, as concentrations can be as high as four million grains per gram (Traverse, 2007). The abundance of pollen in a sample lends it to robust statistical analysis for the quantitative reconstruction of environments. The outer cell wall is resistant to decay in sediments and allows palynomorphs (pollen and spores) to record changes in plant communities and sea level over millions of years. These characteristics make pollen and spores a powerful tool to use in sea-level research.This chapter describes the biology of pollen and spores and how they are transported and preserved in sediments. We present a methodology for isolating pollen from sediments and a general language and framework to identify pollen as well as light micrographs of a selection of common pollen grains, We then discuss their utility in sea-level research.

  19. A combinatorial approach to angiosperm pollen morphology.

    Science.gov (United States)

    Mander, Luke

    2016-11-30

    Angiosperms (flowering plants) are strikingly diverse. This is clearly expressed in the morphology of their pollen grains, which are characterized by enormous variety in their shape and patterning. In this paper, I approach angiosperm pollen morphology from the perspective of enumerative combinatorics. This involves generating angiosperm pollen morphotypes by algorithmically combining character states and enumerating the results of these combinations. I use this approach to generate 3 643 200 pollen morphotypes, which I visualize using a parallel-coordinates plot. This represents a raw morphospace. To compare real-world and theoretical morphologies, I map the pollen of 1008 species of Neotropical angiosperms growing on Barro Colorado Island (BCI), Panama, onto this raw morphospace. This highlights that, in addition to their well-documented taxonomic diversity, Neotropical rainforests also represent an enormous reservoir of morphological diversity. Angiosperm pollen morphospace at BCI has been filled mostly by pollen morphotypes that are unique to single plant species. Repetition of pollen morphotypes among higher taxa at BCI reflects both constraint and convergence. This combinatorial approach to morphology addresses the complexity that results from large numbers of discrete character combinations and could be employed in any situation where organismal form can be captured by discrete morphological characters. © 2016 The Author(s).

  20. Pollen viability and membrane lipid composition

    NARCIS (Netherlands)

    Bilsen, van D.G.J.L.

    1993-01-01

    In this thesis membrane lipid composition is studied in relation to pollen viability during storage. Chapter 1 reviews pollen viability, membranes in the dry state and membrane changes associated with cellular aging. This chapter is followed by a study of age-related changes in phospholipid

  1. Direct electron transfer of glucose oxidase promoted by carbon nanotubes is without value in certain mediator-free applications

    International Nuclear Information System (INIS)

    Wang, Y.; Yao, Y.

    2012-01-01

    We have investigated the direct electron transfer (DET) promoted by carbon nanotubes (CNTs) on an electrode containing immobilized glucose oxidase (GOx) with the aim to develop a third-generation glucose biosensor and a mediator-free glucose biofuel cell anode. GOx was immobilized via chitosan (CS) on a glassy carbon electrode (GCE) modified with multi-walled carbon nanotubes (MWCNTs). Cyclic voltammetric revealed that the GOx on the surface of such an electrode is unable to simultaneously demonstrate DET with the electrode and to retain its catalytic activity towards glucose, although the MWCNTs alone can promote electron transfer between GOx and electrode. This is interpreted in terms of two types of GOx on the surface, the distribution and properties of which are quite different. The first type exhibits DET capability that results from the collaboration of MWCNTs and metal impurities, but is unable to catalyze the oxidation of glucose. The second type maintains its glucose-specific catalytic capability in the presence of a mediator, which can be enhanced by MWCNTs, but cannot undergo DET with the electrode. As a result, the MWCNTs are capable of promoting the electron transfer, but this is without value in some mediator-free applications such as in third-generation glucose biosensors and in mediator-free anodes for glucose biofuel cells. (author)

  2. ENHANCING DIRECT ELECTRON TRANSFER OF GLUCOSE OXIDASE USING A GOLD NANOPARTICLE |TITANATE NANOTUBE NANOCOMPOSITE ON A BIOSENSOR

    International Nuclear Information System (INIS)

    Zhao, Ruoxia; Liu, Xiaoqiang; Zhang, Jiamei; Zhu, Jie; Wong, Danny K.Y.

    2015-01-01

    ABSTRACT: In this paper, we have developed a gold nanoparticle (GNP) decorated titanate nanotubes (TNT) nanocomposite that aids in the direct electron transfer of a large enzyme, such as glucose oxidase (GOD), in which the electroactive site of flavin adenine dinucleotide is deeply buried within the enzyme. The ionic liquid, brominated 1-decyl-3-methyl imidazole, was used to immobilise the nanocomposite and the enzyme on a glassy carbon electrode to further aid in the electron transfer between GOD and the electrode surface. Nafion was also added to anchor the biosensor scaffold. Initially, the tubiform geometry of titanate nanomaterials and the GNP-TNT nanocomposite was confirmed by microscopic and spectroscopic techniques before glucose oxidase was entrapped in the nanocomposite. Based on voltammetric results, this biosensor showed a strong electrocatalytic capability towards glucose (with a heterogeneous electron transfer rate constant of 7.1 s −1 at 180 mV s −1 ) and the calibration for glucose exhibited a high sensitivity (5.1 μA mM −1 ) and a wide linear range (0.01–1.2 mM). These results demonstrated superior analytical performance of our biosensor over others fabricated using bulkier TiO 2 nanoparticles or nanobundles, which could be attributed to a high degree of biocompatibility to glucose oxidase and electrical conductivity of the nanocomposite

  3. Rapid Stencil Mask Fabrication Enabled One-Step Polymer-Free Graphene Patterning and Direct Transfer for Flexible Graphene Devices.

    Science.gov (United States)

    Yong, Keong; Ashraf, Ali; Kang, Pilgyu; Nam, SungWoo

    2016-04-27

    We report a one-step polymer-free approach to patterning graphene using a stencil mask and oxygen plasma reactive-ion etching, with a subsequent polymer-free direct transfer for flexible graphene devices. Our stencil mask is fabricated via a subtractive, laser cutting manufacturing technique, followed by lamination of stencil mask onto graphene grown on Cu foil for patterning. Subsequently, micro-sized graphene features of various shapes are patterned via reactive-ion etching. The integrity of our graphene after patterning is confirmed by Raman spectroscopy. We further demonstrate the rapid prototyping capability of a stretchable, crumpled graphene strain sensor and patterned graphene condensation channels for potential applications in sensing and heat transfer, respectively. We further demonstrate that the polymer-free approach for both patterning and transfer to flexible substrates allows the realization of cleaner graphene features as confirmed by water contact angle measurements. We believe that our new method promotes rapid, facile fabrication of cleaner graphene devices, and can be extended to other two dimensional materials in the future.

  4. Gene doping detection: evaluation of approach for direct detection of gene transfer using erythropoietin as a model system.

    Science.gov (United States)

    Baoutina, A; Coldham, T; Bains, G S; Emslie, K R

    2010-08-01

    As clinical gene therapy has progressed toward realizing its potential, concern over misuse of the technology to enhance performance in athletes is growing. Although 'gene doping' is banned by the World Anti-Doping Agency, its detection remains a major challenge. In this study, we developed a methodology for direct detection of the transferred genetic material and evaluated its feasibility for gene doping detection in blood samples from athletes. Using erythropoietin (EPO) as a model gene and a simple in vitro system, we developed real-time PCR assays that target sequences within the transgene complementary DNA corresponding to exon/exon junctions. As these junctions are absent in the endogenous gene due to their interruption by introns, the approach allows detection of trace amounts of a transgene in a large background of the endogenous gene. Two developed assays and one commercial gene expression assay for EPO were validated. On the basis of ability of these assays to selectively amplify transgenic DNA and analysis of literature on testing of gene transfer in preclinical and clinical gene therapy, it is concluded that the developed approach would potentially be suitable to detect gene doping through gene transfer by analysis of small volumes of blood using regular out-of-competition testing.

  5. Direct Observation of Double Hydrogen Transfer via Quantum Tunneling in a Single Porphycene Molecule on a Ag(110) Surface.

    Science.gov (United States)

    Koch, Matthias; Pagan, Mark; Persson, Mats; Gawinkowski, Sylwester; Waluk, Jacek; Kumagai, Takashi

    2017-09-13

    Quantum tunneling of hydrogen atoms (or protons) plays a crucial role in many chemical and biological reactions. Although tunneling of a single particle has been examined extensively in various one-dimensional potentials, many-particle tunneling in high-dimensional potential energy surfaces remains poorly understood. Here we present a direct observation of a double hydrogen atom transfer (tautomerization) within a single porphycene molecule on a Ag(110) surface using a cryogenic scanning tunneling microscope (STM). The tautomerization rates are temperature independent below ∼10 K, and a large kinetic isotope effect (KIE) is observed upon substituting the transferred hydrogen atoms by deuterium, indicating that the process is governed by tunneling. The observed KIE for three isotopologues and density functional theory calculations reveal that a stepwise transfer mechanism is dominant in the tautomerization. It is also found that the tautomerization rate is increased by vibrational excitation via an inelastic electron tunneling process. Moreover, the STM tip can be used to manipulate the tunneling dynamics through modification of the potential landscape.

  6. Apparent directional mass-transfer capacity coefficients in three-dimensional anisotropic heterogeneous aquifers under radial convergent transport

    Science.gov (United States)

    Pedretti, D.; Fernàndez-Garcia, D.; Sanchez-Vila, X.; Bolster, D.; Benson, D. A.

    2014-02-01

    Aquifer hydraulic properties such as hydraulic conductivity (K) are ubiquitously heterogeneous and typically only a statistical characterization can be sought. Additionally, statistical anisotropy at typical characterization scales is the rule. Thus, regardless of the processes governing solute transport at the local (pore) scale, transport becomes non-Fickian. Mass-transfer models provide an efficient tool that reproduces observed anomalous transport; in some cases though, these models lack predictability as model parameters cannot readily be connected to the physical properties of aquifers. In this study, we focus on a multirate mass-transfer model (MRMT), and in particular the apparent capacity coefficient (β), which is a strong indicator of the potential of immobile zones to capture moving solute. We aim to find if the choice of an apparent β can be phenomenologically related to measures of statistical anisotropy. We analyzed an ensemble of random simulations of three-dimensional log-transformed multi-Gaussian permeability fields with stationary anisotropic correlation under convergent flow conditions. It was found that apparent β also displays an anisotropic behavior, physically controlled by the aquifer directional connectivity, which in turn is controlled by the anisotropic correlation model. A high hydraulic connectivity results in large β values. These results provide new insights into the practical use of mass-transfer models for predictive purposes.

  7. Direct measurement of adhesion energy of monolayer graphene as-grown on copper and its application to renewable transfer process.

    Science.gov (United States)

    Yoon, Taeshik; Shin, Woo Cheol; Kim, Taek Yong; Mun, Jeong Hun; Kim, Taek-Soo; Cho, Byung Jin

    2012-03-14

    Direct measurement of the adhesion energy of monolayer graphene as-grown on metal substrates is important to better understand its bonding mechanism and control the mechanical release of the graphene from the substrates, but it has not been reported yet. We report the adhesion energy of large-area monolayer graphene synthesized on copper measured by double cantilever beam fracture mechanics testing. The adhesion energy of 0.72 ± 0.07 J m(-2) was found. Knowing the directly measured value, we further demonstrate the etching-free renewable transfer process of monolayer graphene that utilizes the repetition of the mechanical delamination followed by the regrowth of monolayer graphene on a copper substrate. © 2012 American Chemical Society

  8. Probing the electronic structure of redox species and direct determination of intrinsic reorganization energies of electron transfer reactions

    International Nuclear Information System (INIS)

    Wang, Xue-Bin; Wang, Lai-Sheng

    2000-01-01

    An experimental technique capable of directly determining the intrinsic reorganization energies of bimolecular electron transfer reactions is described. Appropriate solution phase redox species are prepared in the gas phase using electrospray ionization and probed using photodetachment spectroscopy. Five metal complex anions involved in the Fe 2+ -Fe 3+ redox couple are investigated and the intramolecular reorganization energies are measured directly from spectral features due to removing the most loosely bound 3d electron from the Fe(II)-complexes. The photodetachment spectra also yield electronic structure information about the Fe 2+ -Fe 3+ redox couple and provide a common electronic structure origin for the reducing capability of the Fe(II)-complexes, the most common redox reagents. (c) 2000 American Institute of Physics

  9. Aerobiology and pollen allergy in Islamabad

    Energy Technology Data Exchange (ETDEWEB)

    Abbas, S [Allergy and Asthma Centre, Islamabad (Pakistan); Raza, S M [Rawalpindi Medical College, Rawalpindi (Pakistan); Khan, M A [Quaid-i-Azam University, Islamabad (Pakistan). Dept. of Plant Sciences

    2009-10-15

    Pollen allergies affect a significant proportion of Islamabad residents. Many patients with pollen allergy Are hospitalized in Islamabad in spring (February to April), fall seasons (July to September) and after monsoons. To determine the type and concentration of airborne pollens causing allergic diseases in the susceptible patients in Islamabad. The study was conducted from January 2005 to December 2006 and Burkard Volumetric Spore Trap' provided by the World Allergy Organization was used. This spore trap was placed in the F-10 area of Islamabad and samples were collected on weekly basis during the whole study period. To obtain the sample, the spore trap drum was loaded with a strip of sticky tape every week. The sampled sticky tape was then collected each week at a specified time and replaced with a fresh strip of sticky tape, which was then collected next week. This cycle , continued for whole study period. From each sample seven permanent slides were made and mounted with gelevitol mounting media; The slides were then examined microscopically. A total of 702 individuals irrespective of age or gender were included in the study. Skin prick tests were performed for pollens using allergen extracts of Hollister-Steir, USA and the results were recorded. The two flowering seasons in Islamabad i.e., spring and fall caused maximum pollen allergies. The Broussonetia papyrifera (paper mulberry) tree in spring, and the Cannabis sativa (bhang) weed in the fall season, Produced the highest seasonal pollen counts. In the spring season of 2005, Broussonetia papyrifera produced the highest pollen count, (73%) of the total pollen count, with a maximum count of 1390 pollen/cu meter of air/hour on 20th of March, while in 2006, it accounted for 75% of the total pollen-count with a maximum count of 1430 pollen/cu meter of air/hour on 10th of March. in fall Season of 2005, Cannabis sativa produced maximum pollen counts of 85 pollens/cu meter of air/hr on 18th of August, while in 2006

  10. MICROBIAL QUALITY OF HONEY MIXTURE WITH POLLEN

    Directory of Open Access Journals (Sweden)

    Ján Mareček

    2011-02-01

    Full Text Available Normal 0 21 MicrosoftInternetExplorer4 The aim of this study was evaluation of microbial quality in raw materials (honey, pollen and evaluation of microbial quality in honey mixture with pollen (2.91 % and 3.85 % and also dynamics of microbial groups in honey mixtures with pollen after 14 days storage at the room temperature (approximately 25 °C and in cold store (8 °C. We used dilution plating method for testing of samples. Detections of total plate microbial count (aerobic and anaerobic microorganisms, sporulating bacteria, coliform bacteria, Bifidobacterium sp., Lactobacillus sp. and microscopic fungi were performed. In general, counts of microorganisms decreased in honey mixture with pollen compared to raw pollen and these counts increased compared to natural honey. Total plate count was 5.37 log KTJ.g-1 in pollen; 1.36 log KTJ.g-1 in honey; 2.97 log KTJ.g-1 in honey mixture with 2.91 % pollen and 2.04 log KTJ.g-1 in honey mixture with 3.85 % pollen. Coliform bacteria were detected in pollen (1.77 log KTJ.g-1. Then, we found coliform bacteria in one sample of honey mixtures with pollen (2.91 % - 1.00 log KTJ.g-1.Bifidobacterium species were detected only in raw pollen. We did not findLactobacillus sp. in any of the samples. Microscopic fungi were detected on two cultivating media. Yeasts were present in pollen sample (average 5.39 log KTJ.g-1, honey mixture with 2.91 % pollen (average 2.51 log KTJ.g-1 and honey mixture with 3.85 % pollen (average 1.58 log KTJ.g-1. Filamentous microscopic fungi were detectable in pollen (average 3.38 log KTJ.g-1, in honey (only on one medium: 1.00 log KTJ.g-1, in honey mixture with 2.91 % pollen (average 1.15 log KTJ.g-1 and in honey mixture with 3.85 % pollen (1.71 %. Raw pollen contained microscopic fungi as Absidiasp., Mucor sp., Alternaria sp. andEmericella nidulans. Honey mixture with 2.91 % pollen after storage (14 days contained lower microbial counts when compared with the sample

  11. Aerobiology and pollen allergy in Islamabad

    International Nuclear Information System (INIS)

    Abbas, S.; Raza, S.M.; Khan, M.A.

    2009-01-01

    Pollen allergies affect a significant proportion of Islamabad residents. Many patients with pollen allergy Are hospitalized in Islamabad in spring (February to April), fall seasons (July to September) and after monsoons. To determine the type and concentration of airborne pollens causing allergic diseases in the susceptible patients in Islamabad. The study was conducted from January 2005 to December 2006 and Burkard Volumetric Spore Trap' provided by the World Allergy Organization was used. This spore trap was placed in the F-10 area of Islamabad and samples were collected on weekly basis during the whole study period. To obtain the sample, the spore trap drum was loaded with a strip of sticky tape every week. The sampled sticky tape was then collected each week at a specified time and replaced with a fresh strip of sticky tape, which was then collected next week. This cycle , continued for whole study period. From each sample seven permanent slides were made and mounted with gelevitol mounting media; The slides were then examined microscopically. A total of 702 individuals irrespective of age or gender were included in the study. Skin prick tests were performed for pollens using allergen extracts of Hollister-Steir, USA and the results were recorded. The two flowering seasons in Islamabad i.e., spring and fall caused maximum pollen allergies. The Broussonetia papyrifera (paper mulberry) tree in spring, and the Cannabis sativa (bhang) weed in the fall season, Produced the highest seasonal pollen counts. In the spring season of 2005, Broussonetia papyrifera produced the highest pollen count, (73%) of the total pollen count, with a maximum count of 1390 pollen/cu meter of air/hour on 20th of March, while in 2006, it accounted for 75% of the total pollen-count with a maximum count of 1430 pollen/cu meter of air/hour on 10th of March. in fall Season of 2005, Cannabis sativa produced maximum pollen counts of 85 pollens/cu meter of air/hr on 18th of August, while in 2006

  12. A novel method of lengthening the accessory nerve for direct coaptation during nerve repair and nerve transfer procedures.

    Science.gov (United States)

    Tubbs, R Shane; Maldonado, Andrés A; Stoves, Yolanda; Fries, Fabian N; Li, Rong; Loukas, Marios; Oskouian, Rod J; Spinner, Robert J

    2018-01-01

    OBJECTIVE The accessory nerve is frequently repaired or used for nerve transfer. The length of accessory nerve available is often insufficient or marginal (under tension) for allowing direct coaptation during nerve repair or nerve transfer (neurotization), necessitating an interpositional graft. An attractive maneuver would facilitate lengthening of the accessory nerve for direct coaptation. The aim of the present study was to identify an anatomical method for such lengthening. METHODS In 20 adult cadavers, the C-2 or C-3 connections to the accessory nerve were identified medial to the sternocleidomastoid (SCM) muscle and the anatomy of the accessory nerve/cervical nerve fibers within the SCM was documented. The cervical nerve connections were cut. Lengths of the accessory nerve were measured. Samples of the cut C-2 and C-3 nerves were examined using immunohistochemistry. RESULTS The anatomy and adjacent neural connections within the SCM are complicated. However, after the accessory nerve was "detethered" from within the SCM and following transection, the additional length of the accessory nerve increased from a mean of 6 cm to a mean of 10.5 cm (increase of 4.5 cm) after cutting the C-2 connections, and from a mean of 6 cm to a mean length of 9 cm (increase of 3.5 cm) after cutting the C-3 connections. The additional length of accessory nerve even allowed direct repair of an infraclavicular target (i.e., the proximal musculocutaneous nerve). The cervical nerve connections were shown not to contain motor fibers. CONCLUSIONS An additional length of the accessory nerve made available in the posterior cervical triangle can facilitate direct repair or neurotization procedures, thus eliminating the need for an interpositional nerve graft, decreasing the time/distance for regeneration and potentially improving clinical outcomes.

  13. State of the Art in Transfer Functions for Direct Volume Rendering

    KAUST Repository

    Ljung, Patric; Krü ger, Jens; Groller, Eduard; Hadwiger, Markus; Hansen, Charles D.; Ynnerman, Anders

    2016-01-01

    A central topic in scientific visualization is the transfer function (TF) for volume rendering. The TF serves a fundamental role in translating scalar and multivariate data into color and opacity to express and reveal the relevant features present in the data studied. Beyond this core functionality, TFs also serve as a tool for encoding and utilizing domain knowledge and as an expression for visual design of material appearances. TFs also enable interactive volumetric exploration of complex data. The purpose of this state-of-the-art report (STAR) is to provide an overview of research into the various aspects of TFs, which lead to interpretation of the underlying data through the use of meaningful visual representations. The STAR classifies TF research into the following aspects: dimensionality, derived attributes, aggregated attributes, rendering aspects, automation, and user interfaces. The STAR concludes with some interesting research challenges that form the basis of an agenda for the development of next generation TF tools and methodologies. © 2016 The Author(s) Computer Graphics Forum © 2016 The Eurographics Association and John Wiley & Sons Ltd. Published by John Wiley & Sons Ltd.

  14. State of the Art in Transfer Functions for Direct Volume Rendering

    KAUST Repository

    Ljung, Patric

    2016-07-04

    A central topic in scientific visualization is the transfer function (TF) for volume rendering. The TF serves a fundamental role in translating scalar and multivariate data into color and opacity to express and reveal the relevant features present in the data studied. Beyond this core functionality, TFs also serve as a tool for encoding and utilizing domain knowledge and as an expression for visual design of material appearances. TFs also enable interactive volumetric exploration of complex data. The purpose of this state-of-the-art report (STAR) is to provide an overview of research into the various aspects of TFs, which lead to interpretation of the underlying data through the use of meaningful visual representations. The STAR classifies TF research into the following aspects: dimensionality, derived attributes, aggregated attributes, rendering aspects, automation, and user interfaces. The STAR concludes with some interesting research challenges that form the basis of an agenda for the development of next generation TF tools and methodologies. © 2016 The Author(s) Computer Graphics Forum © 2016 The Eurographics Association and John Wiley & Sons Ltd. Published by John Wiley & Sons Ltd.

  15. A flexible thermoresponsive cell culture substrate for direct transfer of keratinocyte cell sheets.

    Science.gov (United States)

    Praveen, Wulligundam; Madathil, Bernadette K; Sajin Raj, R S; Kumary, T V; Anil Kumar, P R

    2017-10-25

    Most cell sheet engineering systems require a support or carrier to handle the harvested cell sheets. In this study, polyethylene terephthalate-based overhead projection transparency sheets (OHPS) were subjected to surface hydrolysis by alkali treatment to increase pliability and hydrophilicity and enable poly(N-isopropylacrylamide-co-glycidylmethacrylate) copolymer (NGMA) coating to impart thermoresponsiveness. NGMA was applied on the modified OHPS by the technique of spin coating using an indigenously designed spin coater. The spin coating had the advantage of using low volumes of the polymer and a reduced coating time. The surface chemistry and thermoresponsive coating was analyzed by Fourier transform infrared spectroscopy and water contact angle. Human keratinocyte cells were cultured on the spin coated surface and scaffold-free cell sheets were successfully harvested by simple variation of temperature. These cell sheets were found to be viable, exhibited epithelial characteristic and cell-cell contact as confirmed by positive immunostaining for ZO-1. The integrity and morphology of the cell sheet was confirmed by stereomicroscopy and E-SEM. These results highlight the potential of the NGMA spin coated modified OHPS to serve as a thermoresponsive culture surface-cum-flexible transfer tool.

  16. Direct and large eddy simulation of turbulent heat transfer at very low Prandtl number: Application to lead–bismuth flows

    International Nuclear Information System (INIS)

    Bricteux, L.; Duponcheel, M.; Winckelmans, G.; Tiselj, I.; Bartosiewicz, Y.

    2012-01-01

    Highlights: ► We perform direct and hybrid-large eddy simulations of high Reynolds and low Prandtl turbulent wall-bounded flows with heat transfer. ► We use a state-of-the-art numerical methods with low energy dissipation and low dispersion. ► We use recent multiscalesubgrid scale models. ► Important results concerning the establishment of near wall modeling strategy in RANS are provided. ► The turbulent Prandtl number that is predicted by our simulation is different than that proposed by some correlations of the literature. - Abstract: This paper deals with the issue of modeling convective turbulent heat transfer of a liquid metal with a Prandtl number down to 0.01, which is the order of magnitude of lead–bismuth eutectic in a liquid metal reactor. This work presents a DNS (direct numerical simulation) and a LES (large eddy simulation) of a channel flow at two different Reynolds numbers, and the results are analyzed in the frame of best practice guidelines for RANS (Reynolds averaged Navier–Stokes) computations used in industrial applications. They primarily show that the turbulent Prandtl number concept should be used with care and that even recent proposed correlations may not be sufficient.

  17. Use of MODIS Satellite Images and an Atmospheric Dust Transport Model to Evaluate Juniperus spp. Pollen Phenology and Transport

    Science.gov (United States)

    Luvall, J. C.; Sprigg, W. A.; Levetin, E.; Huete, A.; Nickovic, S.; Pejanovic, G. A.; Vukovic, A.; Van de Water, P. K.; Myers, O. B.; Budge, A. M.; hide

    2011-01-01

    Pollen can be transported great distances. Van de Water et al., 2003 reported Juniperus spp. pollen, a significant aeroallergen was transported 200-600 km. Hence local observations of plant phenology may not be consistent with the timing and source of pollen collected by pollen sampling instruments. Direct detection of pollen via satellite is not practical. A practical alternative combines modeling and phenological observations using ground based sampling and satellite data. The DREAM (Dust REgional Atmospheric Model) is a verified model for atmospheric dust transport modeling using MODIS data products to identify source regions and quantities of dust (Nickovic et al. 2001). The use of satellite data products for studying phenology is well documented (White and Nemani 2006). In the current project MODIS data will provide critical input to the PREAM model providing pollen source location, timing of pollen release, and vegetation type. We are modifying the DREAM model (PREAM - Pollen REgional Atmospheric Model) to incorporate pollen transport. The linkages already exist with DREAM through PHAiRS (Public Health Applications in Remote Sensing) to the public health community. This linkage has the potential to fill this data gap so that the potential association of health effects of pollen can better be tracked for possible linkage with health outcome data which may be associated with asthma, respiratory effects, myocardial infarction, and lost workdays. Juniperus spp. pollen phenology may respond to a wide range of environmental factors such as day length, growing degree-days, precipitation patterns and soil moisture. Species differences are also important. These environmental factors vary over both time and spatial scales. Ground based networks such as the USA National Phenology Network have been established to provide national wide observations of vegetation phenology. However, the density of observers is not adequate to sufficiently document the phenology variability

  18. Feedback control for distributed heat transfer mechanisms in direct-contact membrane distillation system

    KAUST Repository

    Eleiwi, Fadi; N'Doye, Ibrahima; Laleg-Kirati, Taous-Meriem

    2015-01-01

    In this paper, the problem of stabilization and production rate reference tracking for a Direct-Contact Membrane Distillation (DCMD) system is addressed. Sufficient conditions for the asymptotic and exponential stabilization for DCMD system are presented using the Gronwall-Bellman lemma and Linear Matrix Inequalities (LMIs) approaches, respectively. A nonlinear observer is then proposed to estimate the temperature distribution among the DCMD domain. This contributes to propose a reference production rate control design for the DCMD process via observer-based output control approach. Finally, numerical simulations are given to show the effectiveness of the proposed methods.

  19. Feedback control for distributed heat transfer mechanisms in direct-contact membrane distillation system

    KAUST Repository

    Eleiwi, Fadi

    2015-09-21

    In this paper, the problem of stabilization and production rate reference tracking for a Direct-Contact Membrane Distillation (DCMD) system is addressed. Sufficient conditions for the asymptotic and exponential stabilization for DCMD system are presented using the Gronwall-Bellman lemma and Linear Matrix Inequalities (LMIs) approaches, respectively. A nonlinear observer is then proposed to estimate the temperature distribution among the DCMD domain. This contributes to propose a reference production rate control design for the DCMD process via observer-based output control approach. Finally, numerical simulations are given to show the effectiveness of the proposed methods.

  20. Directional radiative transfer by SCOPE, SLC and DART using laser scan derived structural forest parameters

    Science.gov (United States)

    Timmermans, Joris; Gastellu-Etchegorry, Jean Philippe; van der Tol, Christiaan; Verhoef, Wout; Vekerdy, Zoltan; Su, Zhongbo

    2017-04-01

    Accurate estimation of the radiative transfer (RT) over vegetation is the corner stone of agricultural and hydrological remote sensing applications. Present remote sensing sensors mostly use traditional optical, thermal and microwave observations. However with these traditional observations characterization of the light efficiency and photosynthetic rate can only be accomplished indirectly. A promising new method of observing these processes is by using the fluorescent emitted radiation. This approach was recently highlighted due to the selection of the FLEX sensor as a future Earth Explorer by the European Space agency (ESA). Several modelling activities have been undertaken to better understand the technical feasibilities of this sensor. Within these studies, the SCOPE model has been chosen as the baseline algorithm. This model combines a detailed RT description of the canopy, using a discrete version of the SAIL model, with a description of photosynthetic processes (by use of the Farquhar/Ball-Berry model). Consequently, this model is capable of simulating simultaneously the biophysical processes and jointly the fluorescent, optical and thermal RT. The SAIL model however is a 1D RT model and consequently provides higher uncertainties with increasing vegetation structures. The main objective of this research is to investigate the limitations of the RT model component of the SCOPE model over complex canopies. In particular the aim of this research is to evaluate the validity for increasingly structural complex canopies', on the bidirectional reflectance distribution functions (BRDF) of these canopies. This was accomplished by evaluating the simulated outgoing radiation from SCOPE/SAIL against simulations of the DART 3D RT model. In total nine different scenarios were simulated with the DART RTM with increasing structural complexity, ranging from the simple 'Plot' scenario to the highly complex 'Multiple Crown' scenario. The canopy parameters are retrieved from a

  1. Exploring the transfer of recent plant photosynthates to soil microbes: mycorrhizal pathway vs direct root exudation

    Science.gov (United States)

    Kaiser, Christina; Kilburn, Matt R; Clode, Peta L; Fuchslueger, Lucia; Koranda, Marianne; Cliff, John B; Solaiman, Zakaria M; Murphy, Daniel V

    2015-01-01

    Plants rapidly release photoassimilated carbon (C) to the soil via direct root exudation and associated mycorrhizal fungi, with both pathways promoting plant nutrient availability. This study aimed to explore these pathways from the root's vascular bundle to soil microbial communities. Using nanoscale secondary ion mass spectrometry (NanoSIMS) imaging and 13C-phospho- and neutral lipid fatty acids, we traced in-situ flows of recently photoassimilated C of 13CO2-exposed wheat (Triticum aestivum) through arbuscular mycorrhiza (AM) into root- and hyphae-associated soil microbial communities. Intraradical hyphae of AM fungi were significantly 13C-enriched compared to other root-cortex areas after 8 h of labelling. Immature fine root areas close to the root tip, where AM features were absent, showed signs of passive C loss and co-location of photoassimilates with nitrogen taken up from the soil solution. A significant and exclusively fresh proportion of 13C-photosynthates was delivered through the AM pathway and was utilised by different microbial groups compared to C directly released by roots. Our results indicate that a major release of recent photosynthates into soil leave plant roots via AM intraradical hyphae already upstream of passive root exudations. AM fungi may act as a rapid hub for translocating fresh plant C to soil microbes. PMID:25382456

  2. Novel Naphthalene Based Lariat-Type Crown Ethers Using Direct Single Electron Transfer Photochemical Strategy

    International Nuclear Information System (INIS)

    Park, Hea Jung; Sung, Nam Kyung; Kim, Su Rhan; Kim, Su Rhan; Ahn, So Hyun; Yoon, Ung Chan; Cho, Dae Won; Mariano, Patrick S.

    2013-01-01

    This study explored a direct SET-photochemical strategy to construct a new family of thioene conjugated-naphthalamide fluorophore based lariat-crown ethers which show strong binding properties towards heavy metal ions. Irradiations of designed nitrogen branched (trimethylsilyl)methylthio-terminated polyethylenoxy-tethered naphthalimides in acidic methanol solutions have led to highly efficient photocyclization reactions to generate naphthalamide based lariat type thiadiazacrown ethers directly in chemo- and regio-selective manners which undergo very facile secondary dehydration reactions during separation processes to produce their corresponding amidoenethio ether cyclic products tethered with electron donating diethyleneoxy- and diethyenethio-side arm chains. Fluorescence and metal cation binding properties of the lariat type enamidothio products were examined. The photocyclized amidoenethio products, thioene conjugated naphthalamide fluorophore containing lariat-thiadiazacrowns exhibited strong fluorescence emissions in region of 330-450 nm along with intramolecular exciplex emissions in region of 450-560 nm with their maxima at 508 nm. Divalent cation Hg 2+ and Pb 2+ showed strong binding to sulfur atom(s) in side arm chain and atoms in enethiadiazacrown ether rings which led to significant enhancement of fluorescence from its chromophore singlet excited state and concomitant quenching of exciplex emission. The dual fluorescence emission responses towards divalent cations might provide a new guide for design and development of fluorescence sensors for detecting those metals

  3. Novel Naphthalene Based Lariat-Type Crown Ethers Using Direct Single Electron Transfer Photochemical Strategy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hea Jung; Sung, Nam Kyung; Kim, Su Rhan; Kim, Su Rhan; Ahn, So Hyun; Yoon, Ung Chan [Pusan National Univ., Busan (Korea, Republic of); Cho, Dae Won [Yeungnam Univ., Geoungsan (Korea, Republic of); Mariano, Patrick S. [Univ. of New Mexico, Albuquerque (United States)

    2013-12-15

    This study explored a direct SET-photochemical strategy to construct a new family of thioene conjugated-naphthalamide fluorophore based lariat-crown ethers which show strong binding properties towards heavy metal ions. Irradiations of designed nitrogen branched (trimethylsilyl)methylthio-terminated polyethylenoxy-tethered naphthalimides in acidic methanol solutions have led to highly efficient photocyclization reactions to generate naphthalamide based lariat type thiadiazacrown ethers directly in chemo- and regio-selective manners which undergo very facile secondary dehydration reactions during separation processes to produce their corresponding amidoenethio ether cyclic products tethered with electron donating diethyleneoxy- and diethyenethio-side arm chains. Fluorescence and metal cation binding properties of the lariat type enamidothio products were examined. The photocyclized amidoenethio products, thioene conjugated naphthalamide fluorophore containing lariat-thiadiazacrowns exhibited strong fluorescence emissions in region of 330-450 nm along with intramolecular exciplex emissions in region of 450-560 nm with their maxima at 508 nm. Divalent cation Hg{sup 2+} and Pb{sup 2+} showed strong binding to sulfur atom(s) in side arm chain and atoms in enethiadiazacrown ether rings which led to significant enhancement of fluorescence from its chromophore singlet excited state and concomitant quenching of exciplex emission. The dual fluorescence emission responses towards divalent cations might provide a new guide for design and development of fluorescence sensors for detecting those metals.

  4. Ozone affects pollen viability and NAD(P)H oxidase release from Ambrosia artemisiifolia pollen

    International Nuclear Information System (INIS)

    Pasqualini, Stefania; Tedeschini, Emma; Frenguelli, Giuseppe; Wopfner, Nicole; Ferreira, Fatima; D'Amato, Gennaro; Ederli, Luisa

    2011-01-01

    Air pollution is frequently proposed as a cause of the increased incidence of allergy in industrialised countries. We investigated the impact of ozone (O 3 ) on reactive oxygen species (ROS) and allergen content of ragweed pollen (Ambrosia artemisiifolia). Pollen was exposed to acute O 3 fumigation, with analysis of pollen viability, ROS and nitric oxide (NO) content, activity of nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase, and expression of major allergens. There was decreased pollen viability after O 3 fumigation, which indicates damage to the pollen membrane system, although the ROS and NO contents were not changed or were only slightly induced, respectively. Ozone exposure induced a significant enhancement of the ROS-generating enzyme NAD(P)H oxidase. The expression of the allergen Amb a 1 was not affected by O 3 , determined from the mRNA levels of the major allergens. We conclude that O 3 can increase ragweed pollen allergenicity through stimulation of ROS-generating NAD(P)H oxidase. - Highlights: → O 3 reduces the viability of ragweed pollen. → ROS and allergens of ragweed pollen were not affected by O 3 exposure. → O 3 enhances the activity of the ROS-generating enzyme NAD(P)H oxidase. → O 3 increases ragweed pollen allergenicity through NAD(P)H-oxidase stimulation. - This study focuses on the effects of the atmospheric pollutant ozone on ROS content and NAD(P)H oxidase activity of ragweed pollen grains.

  5. Viper's bugloss (Echium spp. honey typing and establishing the pollen threshold for monofloral honey.

    Directory of Open Access Journals (Sweden)

    Tomás Martín Arroyo

    Full Text Available Honey samples (n = 126 from Castilla-La Mancha (Central Spain were characterized based on their physicochemical properties and a melissopalynological analysis. The latter showed that Echium pollen type was the dominant palynomorph in most samples, representing at least 30% of the pollen in each sample. As anticipated, a relationship was observed between the proportion of this pollen and the properties of the honey. One goal of this study was to set a threshold that defines the percentage of pollen necessary for Viper's bugloss honey to be considered monofloral or multifloral. This is a mandatory requirement in light of the publication of the European Directive 2014/63/EU establishing the regulations governing the labelling and control of honey to eradicate fraud (BOE n° 147, June 2015. By analyzing how the proportions of Echium pollen type affected the physicochemical and sensory parameters of the honey, the honeys analyzed could be segregated into multifloral and monofloral honeys. The data indicates that the proportion of pollen necessary to discriminate monofloral Viper's bugloss honey lies at 70%.

  6. Identification of potential sources of airborne Olea pollen in the Southwest Iberian Peninsula.

    Science.gov (United States)

    Fernández-Rodríguez, Santiago; Skjøth, Carsten Ambelas; Tormo-Molina, Rafael; Brandao, Rui; Caeiro, Elsa; Silva-Palacios, Inmaculada; Gonzalo-Garijo, Angela; Smith, Matt

    2014-04-01

    This study aims to determine the potential origin of Olea pollen recorded in Badajoz in the Southwest of the Iberian Peninsula during 2009-2011. This was achieved using a combination of daily average and diurnal (hourly) airborne Olea pollen counts recorded at Badajoz (south-western Spain) and Évora (south-eastern Portugal), an inventory of olive groves in the studied area and air mass trajectory calculations computed using the HYSPLIT model. Examining olive pollen episodes at Badajoz that had distinctly different diurnal cycles in olive pollen in relation to the mean, allowed us to identify three different scenarios where olive pollen can be transported to the city from either distant or nearby sources during conditions with slow air mass movements. Back trajectory analysis showed that olive pollen can be transported to Badajoz from the West on prevailing winds, either directly or on slow moving air masses, and from high densities of olive groves situated to the Southeast (e.g. Andalucía). Regional scale transport of olive pollen can result in increased nighttime concentrations of this important aeroallergen. This could be particularly important in Mediterranean countries where people can be outdoors during this time due to climate and lifestyle. Such studies that examine sources and the atmospheric transport of pollen are valuable for allergy sufferers and health care professionals because the information can be incorporated into forecasts, the outputs of which are used for avoiding exposure to aeroallergens and planning medication. The results of studies of this nature can also be used for examining gene flow in this important agricultural crop.

  7. Identification of potential sources of airborne Olea pollen in the Southwest Iberian Peninsula

    Science.gov (United States)

    Fernández-Rodríguez, Santiago; Skjøth, Carsten Ambelas; Tormo-Molina, Rafael; Brandao, Rui; Caeiro, Elsa; Silva-Palacios, Inmaculada; Gonzalo-Garijo, Ángela; Smith, Matt

    2014-04-01

    This study aims to determine the potential origin of Olea pollen recorded in Badajoz in the Southwest of the Iberian Peninsula during 2009-2011. This was achieved using a combination of daily average and diurnal (hourly) airborne Olea pollen counts recorded at Badajoz (south-western Spain) and Évora (south-eastern Portugal), an inventory of olive groves in the studied area and air mass trajectory calculations computed using the HYSPLIT model. Examining olive pollen episodes at Badajoz that had distinctly different diurnal cycles in olive pollen in relation to the mean, allowed us to identify three different scenarios where olive pollen can be transported to the city from either distant or nearby sources during conditions with slow air mass movements. Back trajectory analysis showed that olive pollen can be transported to Badajoz from the West on prevailing winds, either directly or on slow moving air masses, and from high densities of olive groves situated to the Southeast (e.g. Andalucía). Regional scale transport of olive pollen can result in increased nighttime concentrations of this important aeroallergen. This could be particularly important in Mediterranean countries where people can be outdoors during this time due to climate and lifestyle. Such studies that examine sources and the atmospheric transport of pollen are valuable for allergy sufferers and health care professionals because the information can be incorporated into forecasts, the outputs of which are used for avoiding exposure to aeroallergens and planning medication. The results of studies of this nature can also be used for examining gene flow in this important agricultural crop.

  8. Laccase on Black Pearl 2000 modified glassy carbon electrode: Characterization of direct electron transfer and biological sensing properties for pyrocatechol

    International Nuclear Information System (INIS)

    Wang Kunqi; Tang Juan; Zhang Zuoming; Gao Ying; Chen Gang

    2012-01-01

    Highlights: ► Laccase can complete direct electron transfer process on BP2000 matrices. ► Laccase immobilized on BP2000 matrices has catalytic oxidation effect to pyrocatechol. ► A pyrocatechol biosensor has constructed been using Nafion/Lac-BP2000/GC electrode. ► Detection limit and linear range of the biosensor are 0.003 mM and 0.003–5.555 mM. - Abstract: In this paper, it was found that Laccase (Lac) could be stably immobilized on the glassy carbon electrode modified with Black Pearl 2000 (BP2000) and Nafion by a simple technique. The adsorption behavior of Lac immobilized on BP2000 matrix was characterized by environment scanning electron microscope (ESEM), ultraviolet–visible (UV–vis) and Fourier transform infrared (FTIR), which demonstrated that BP2000 could facilitate the electron exchange between the active center of Lac and modified electrode. The direct electrochemistry and electrocatalysis behavior of Lac on the modified electrode were characterized by cyclic voltammogram (CV) which indicated that Lac immobilized on the modified electrode displayed a direct, nearly reversible and surface-controlled redox reaction with an enhanced electron-transfer rate constant of 1.940 s −1 at the scan rate of 100 mV s −1 in 0.1 M phosphate buffer solution (PBS) (pH 7.0). Furthermore, it was also discovered that, in the presence of O 2 , Lac immobilized on the modified electrode exhibited the electrocatalytic response to pyrocatechol, and the kinetic apparent Michaelis-constant (K M app ) obtained from the Lineweaver–Burk equation was 1.79 mM. The detection limit, linear range and sensitivity of the Lac biosensor were 0.003 mM, 0.003–5.555 mM and 99.84 μA mM −1 cm −2 , respectively.

  9. Highly Enhanced Electromechanical Stability of Large-Area Graphene with Increased Interfacial Adhesion Energy by Electrothermal-Direct Transfer for Transparent Electrodes.

    Science.gov (United States)

    Kim, Jangheon; Kim, Gi Gyu; Kim, Soohyun; Jung, Wonsuk

    2016-09-07

    Graphene, a two-dimensional sheet of carbon atoms in a hexagonal lattice structure, has been extensively investigated for research and industrial applications as a promising material with outstanding electrical, mechanical, and chemical properties. To fabricate graphene-based devices, graphene transfer to the target substrate with a clean and minimally defective surface is the first step. However, graphene transfer technologies require improvement in terms of uniform transfer with a clean, nonfolded and nontorn area, amount of defects, and electromechanical reliability of the transferred graphene. More specifically, uniform transfer of a large area is a key challenge when graphene is repetitively transferred onto pretransferred layers because the adhesion energy between graphene layers is too low to ensure uniform transfer, although uniform multilayers of graphene have exhibited enhanced electrical and optical properties. In this work, we developed a newly suggested electrothermal-direct (ETD) transfer method for large-area high quality monolayer graphene with less defects and an absence of folding or tearing of the area at the surface. This method delivers uniform multilayer transfer of graphene by repetitive monolayer transfer steps based on high adhesion energy between graphene layers and the target substrate. To investigate the highly enhanced electromechanical stability, we conducted mechanical elastic bending experiments and reliability tests in a highly humid environment. This ETD-transferred graphene is expected to replace commercial transparent electrodes with ETD graphene-based transparent electrodes and devices such as a touch panels with outstanding electromechanical stability.

  10. Cellular interface morphologies in directional solidification. III - The effects of heat transfer and solid diffusivity

    Science.gov (United States)

    Ungar, Lyle H.; Bennett, Mark J.; Brown, Robert A.

    1985-01-01

    The shape and stability of two-dimensional finite-amplitude cellular interfaces arising during directional solidification are compared for several solidification models that account differently for latent heat released at the interface, unequal thermal conductivities of melt and solid, and solute diffusivity in the solid. Finite-element analysis and computer-implemented perturbation methods are used to analyze the families of steadily growing cellular forms that evolve from the planar state. In all models a secondary bifurcation between different families of finite-amplitude cells exists that halves the spatial wavelength of the stable interface. The quantitative location of this transition is very dependent on the details of the model. Large amounts of solute diffusion in the solid retard the growth of large-amplitude cells.

  11. In vitro pollen quantity, viability and germination tests in quince ...

    African Journals Online (AJOL)

    Quince (Cydonia oblonga Mill.) cvs. Ekmek, Esme, Limon, Ege 2, Ege 22, Ege 25 and Quince-A rootstock pollens were collected in April from the unopened pink balloon-stage flowers on mature trees. The pollen amount was between 20063 pollen/flower ('Ege 25') and 11906 pollen/flower ('Limon') with hemacytometer.

  12. Direct repeat sequences are essential for function of the cis-acting locus of transfer (clt) of Streptomyces phaeochromogenes plasmid pJV1.

    Science.gov (United States)

    Franco, Bernardo; González-Cerón, Gabriela; Servín-González, Luis

    2003-11-01

    The functionality of direct and inverted repeat sequences inside the cis acting locus of transfer (clt) of the Streptomyces plasmid pJV1 was determined by testing the effect of different deletions on plasmid transfer. The results show that the single most important element for pJV1 clt function is a series of evenly spaced 9 bp long direct repeats which match the consensus CCGCACA(C/G)(C/G), since their deletion caused a dramatic reduction in plasmid transfer. The presence of these repeats in the absence of any other clt sequences allowed plasmid transfer to occur at a frequency that was at least two orders of magnitude higher than that obtained in the complete absence of clt. A database search revealed regions with a similar organization, and in the same position, in Streptomyces plasmids pSN22 and pSLS, which have transfer proteins homologous to those of pJV1.

  13. PollenCALC: Software for estimation of pollen compatibility of self-incompatible allo- and autotetraploid species

    DEFF Research Database (Denmark)

    Aguirre, Andrea A; Wollenweber, Bernd; Frei, Ursula K

    2012-01-01

    available for predicting pollen haplotype frequencies and pollen compatibility in tetraploid species. Results PollenCALC is a software tool written in C++ programming language that can predict pollen compatibility percentages for polyploid species with a two-locus (S, Z) self-incompatibility system...

  14. Cellobiose Dehydrogenase Aryl Diazonium Modified Single Walled Carbon Nanotubes: Enhanced Direct Electron Transfer through a Positively Charged Surface

    Science.gov (United States)

    2011-01-01

    One of the challenges in the field of biosensors and biofuel cells is to establish a highly efficient electron transfer rate between the active site of redox enzymes and electrodes to fully access the catalytic potential of the biocatalyst and achieve high current densities. We report on very efficient direct electron transfer (DET) between cellobiose dehydrogenase (CDH) from Phanerochaete sordida (PsCDH) and surface modified single walled carbon nanotubes (SWCNT). Sonicated SWCNTs were adsorbed on the top of glassy carbon electrodes and modified with aryl diazonium salts generated in situ from p-aminobenzoic acid and p-phenylenediamine, thus featuring at acidic pH (3.5 and 4.5) negative or positive surface charges. After adsorption of PsCDH, both electrode types showed excellent long-term stability and very efficient DET. The modified electrode presenting p-aminophenyl groups produced a DET current density of 500 μA cm−2 at 200 mV vs normal hydrogen reference electrode (NHE) in a 5 mM lactose solution buffered at pH 3.5. This is the highest reported DET value so far using a CDH modified electrode and comes close to electrodes using mediated electron transfer. Moreover, the onset of the electrocatalytic current for lactose oxidation started at 70 mV vs NHE, a potential which is 50 mV lower compared to when unmodified SWCNTs were used. This effect potentially reduces the interference by oxidizable matrix components in biosensors and increases the open circuit potential in biofuel cells. The stability of the electrode was greatly increased compared with unmodified but cross-linked SWCNTs electrodes and lost only 15% of the initial current after 50 h of constant potential scanning. PMID:21417322

  15. Direct dose mapping versus energy/mass transfer mapping for 4D dose accumulation: fundamental differences and dosimetric consequences.

    Science.gov (United States)

    Li, Haisen S; Zhong, Hualiang; Kim, Jinkoo; Glide-Hurst, Carri; Gulam, Misbah; Nurushev, Teamour S; Chetty, Indrin J

    2014-01-06

    The direct dose mapping (DDM) and energy/mass transfer (EMT) mapping are two essential algorithms for accumulating the dose from different anatomic phases to the reference phase when there is organ motion or tumor/tissue deformation during the delivery of radiation therapy. DDM is based on interpolation of the dose values from one dose grid to another and thus lacks rigor in defining the dose when there are multiple dose values mapped to one dose voxel in the reference phase due to tissue/tumor deformation. On the other hand, EMT counts the total energy and mass transferred to each voxel in the reference phase and calculates the dose by dividing the energy by mass. Therefore it is based on fundamentally sound physics principles. In this study, we implemented the two algorithms and integrated them within the Eclipse treatment planning system. We then compared the clinical dosimetric difference between the two algorithms for ten lung cancer patients receiving stereotactic radiosurgery treatment, by accumulating the delivered dose to the end-of-exhale (EE) phase. Specifically, the respiratory period was divided into ten phases and the dose to each phase was calculated and mapped to the EE phase and then accumulated. The displacement vector field generated by Demons-based registration of the source and reference images was used to transfer the dose and energy. The DDM and EMT algorithms produced noticeably different cumulative dose in the regions with sharp mass density variations and/or high dose gradients. For the planning target volume (PTV) and internal target volume (ITV) minimum dose, the difference was up to 11% and 4% respectively. This suggests that DDM might not be adequate for obtaining an accurate dose distribution of the cumulative plan, instead, EMT should be considered.

  16. Direct Measurements of Energy Transfer between Hot Protons and He+ via EMIC Waves Observed by MMS in the Outer Magnetosphere

    Science.gov (United States)

    Kitamura, N.; Kitahara, M.; Shoji, M.; Miyoshi, Y.; Hasegawa, H.; Nakamura, S.; Katoh, Y.; Saito, Y.; Yokota, S.; Gershman, D. J.; Vinas, A. F.; Giles, B. L.; Moore, T. E.; Paterson, W.; Pollock, C. J.; Russell, C. T.; Strangeway, R. J.; Fuselier, S. A.; Burch, J. L.

    2017-12-01

    Wave-particle interactions have been suggested to play a crucial role in energy transfer in collisionless space plasmas in which the motion of charged particles is controlled by electromagnetic fields. Using an electromagnetic ion cyclotron (EMIC) wave event observed by MMS, we investigate energy transfer between ions and EMIC waves via cyclotron type interactions. To directly detect energy exchange between ions and EMIC waves, we apply the Wave-Particle Interaction Analyzer (WPIA) method that is to calculate the dot product between the wave electric field (Ewave) and ion current perpendicular to the background magnetic field (j). In the cases of resonance, this current is called the resonant current. Near the beginning of the wave event, 15-second averages of j • Ewave reached -0.3 pW/m3 for ions with energies of 14-30 keV and pitch angles of 33.25°-78.75°. The negative value in this pitch angle range indicates that the perpendicular energy of ions was being transferred to the EMIC waves propagating toward Southern higher latitudes at the MMS location by cyclotron resonance. Ion data show non-gyrotropic distributions around the resonance velocity, and that is consistent with the nonlinear trapping of protons by the wave and formation of an electromagnetic proton hole. Near the beginning of the same wave event, strongly phase bunched He+ up to 2 keV with pitch angles slightly larger than 90° were also detected. A positive j • Ewave for the phase bunched He+ indicates that the He+ was being accelerated by the electric field of the EMIC waves. The observed feature of He+ ions is consistent with non-resonant interaction with the wave but is inconsistent with cyclotron resonance. Significantly non-gyrotropic distributions observed in this event demonstrate that different particle populations can strongly couple through wave-particle interactions in the collisionless plasma.

  17. Targeted in vitro and in vivo gene transfer into T Lymphocytes: potential of direct inhibition of allo-immune activation

    Directory of Open Access Journals (Sweden)

    Mehra Mandeep R

    2006-11-01

    Full Text Available Abstract Background Successful inhibition of alloimmune activation in organ transplantation remains one of the key events in achieving a long-term graft survival. Since T lymphocytes are largely responsible for alloimmune activation, targeted gene transfer of gene of cyclin kinase inhibitor p21 into T cells might inhibit their aberrant proliferation. A number of strategies using either adenoviral or lentiviral vectors linked to mono or bispecific antibodies directed against T cell surface markers/cytokines did not yield the desired results. Therefore, this study was designed to test if a CD3promoter-p21 chimeric construct would in vitro and in vivo transfer p21 gene to T lymphocytes and result in inhibition of proliferation. CD3 promoter-p21 chimeric constructs were prepared with p21 in the sense and antisense orientation. For in vitro studies EL4-IL-2 thyoma cells were used and for in vivo studies CD3p21 sense and antisense plasmid DNA was injected intramuscularly in mice. Lymphocyte proliferation was quantified by 3H-thymidine uptake assay; IL-2 mRNA expression was studied by RT-PCR and using Real Time PCR assay, we monitored the CD3, p21, TNF-α and IFN-γ mRNA expression. Results Transfection of CD3p21 sense and antisense in mouse thyoma cell line (EL4-IL-2 resulted in modulation of mitogen-induced proliferation. The intramuscular injection of CD3p21 sense and antisense plasmid DNA into mice also modulated lymphocyte proliferation and mRNA expression of pro-inflammatory cytokines. Conclusion These results demonstrate a novel strategy of in vitro and in vivo transfer of p21 gene to T cells using CD3-promoter to achieve targeted inhibition of lymphocyte proliferation and immune activation.

  18. Common ragweed (Ambrosia artemisiifolia L.): allergenicity and molecular characterization of pollen after plant exposure to elevated NO2.

    Science.gov (United States)

    Zhao, Feng; Elkelish, Amr; Durner, Jörg; Lindermayr, Christian; Winkler, J Barbro; Ruёff, Franziska; Behrendt, Heidrun; Traidl-Hoffmann, Claudia; Holzinger, Andreas; Kofler, Werner; Braun, Paula; von Toerne, Christine; Hauck, Stefanie M; Ernst, Dieter; Frank, Ulrike

    2016-01-01

    Ragweed pollen is the main cause of allergenic diseases in Northern America, and the weed has become a spreading neophyte in Europe. Climate change and air pollution are speculated to affect the allergenic potential of pollen. The objective of this study was to investigate the effects of NO2 , a major air pollutant, under controlled conditions, on the allergenicity of ragweed pollen. Ragweed was exposed to different levels of NO2 throughout the entire growing season, and its pollen further analysed. Spectroscopic analysis showed increased outer cell wall polymers and decreased amounts of pectin. Proteome studies using two-dimensional difference gel electrophoresis and liquid chromatography-tandem mass spectrometry indicated increased amounts of several Amb a 1 isoforms and of another allergen with great homology to enolase Hev b 9 from rubber tree. Analysis of protein S-nitrosylation identified nitrosylated proteins in pollen from both conditions, including Amb a 1 isoforms. However, elevated NO2 significantly enhanced the overall nitrosylation. Finally, we demonstrated increased overall pollen allergenicity by immunoblotting using ragweed antisera, showing a significantly higher allergenicity for Amb a 1. The data highlight a direct influence of elevated NO2 on the increased allergenicity of ragweed pollen and a direct correlation with an increased risk for human health. © 2015 John Wiley & Sons Ltd.

  19. Bee Pollen: Chemical Composition and Therapeutic Application

    Directory of Open Access Journals (Sweden)

    Katarzyna Komosinska-Vassev

    2015-01-01

    Full Text Available Bee pollen is a valuable apitherapeutic product greatly appreciated by the natural medicine because of its potential medical and nutritional applications. It demonstrates a series of actions such as antifungal, antimicrobial, antiviral, anti-inflammatory, hepatoprotective, anticancer immunostimulating, and local analgesic. Its radical scavenging potential has also been reported. Beneficial properties of bee pollen and the validity for their therapeutic use in various pathological condition have been discussed in this study and with the currently known mechanisms, by which bee pollen modulates burn wound healing process.

  20. Pollen Flora of Pakistan-LXV, berberidaceae

    International Nuclear Information System (INIS)

    Perveen, A.

    2010-01-01

    Pollen morphology of 12 species representing 2 genera of the family Berberidaceae from Pakistan has been examined by light and scanning electron microscope. Pollen grains usually radially symmetrical, iso polar or apolar, spheroidal or sub-prolate, spiroaperturate rarely colpate (3- more), sexine thicker than nexine. Tectal surface mostly foveolate-fossulate or sub-psilate, often rugulate - reticulate. On the basis of apertutal types and exine ornamentation four distinct pollen types are recognized, viz., Berberis calliobotrys-type, Berberis jaeschkeana-type, Berberis kunawurensis-type and Epimedium elatum-type. (author)

  1. Inverse and direct transfer functions for the fatigue follow-up of piping systems submitted to stratification

    International Nuclear Information System (INIS)

    Guyette, M.; De Smet, M.

    1995-01-01

    In this paper we outline a methodology to assess the fatigue induced in piping systems submitted to thermal stratification. More specifically, the transformation from the measured outer wall temperature time histories to stress time histories in any point of the line is treated.By means of inverse transfer functions, the fluid temperature distribution is calculated from the outside wall temperatures measured in a limited number of temperature sections. Using direct transfer functions, the local stresses due to stratification may be determined as well as the pipe free curvatures and the pipe free axial strains. Using a finite beam element model of the line, the global response of the line (in terms of displacements or stresses) due to the applied curvatures, axial strains, end point displacements, internal pressure and possible contacts with the pipe environment may be determined.The method is illustrated for the surge lines of the Doel 2 and Doel 4 nuclear power plants. An excellent correlation is found between measured and calculated displacements. Typical stress time histories are shown for a plant cool down. ((orig.))

  2. A simple fish physiological model for radioecologists exemplified for 54Mn direct transfer and rainbow trout (Oncorhynchus mykiss W.)

    International Nuclear Information System (INIS)

    Garnier-Laplace, Jacqueline; Adam, Christelle; Lathuilliere, Thierry; Baudin, Jean-pierre; Clabaut, Mathieu

    2000-01-01

    A simple kinetic model for the transfer of radionuclide to freshwater fish was formulated based on physiological (blood and flow rates), anatomical (volume of tissue compartments) and thermodynamic (tissue-to-blood partition coefficients) parameters. The present study describes 54 Mn direct transfer to young rainbow trout and exemplifies this new approach for radioecology. The model was calibrated on uptake and depuration kinetics datasets obtained for 14 organs/tissues during a 12-week experiment. Organs were classified into three compartments: an input compartment (gills), a distribution/reservoir compartment (muscles, skeleton and skin) and an excretional function compartment (digestive system and liver). For the three compartments, the partition coefficients and the residence time of the pollutant were, respectively: 161 and 4 h, 87 and 1.5 days, and 1465 and 14 days. As an indirect validation technique, a steady-state concentration factor was calculated for the whole organism from the partition coefficient values and fractional volumes of the compartment. The value of 8 l kg -1 w.w. is similar to those reported in the literature

  3. Infectivity of DWV associated to flower pollen: experimental evidence of a horizontal transmission route.

    Directory of Open Access Journals (Sweden)

    Maurizio Mazzei

    Full Text Available Deformed wing virus (DWV is a honeybee pathogen whose presence is generally associated with infestation of the colony by the mite Varroa destructor, leading to the onset of infections responsible for the collapse of the bee colony. DWV contaminates bee products such as royal jelly, bee-bread and honey stored within the infected hive. Outside the hive, DWV has been found in pollen loads collected directly from infected as well as uninfected forager bees. It has been shown that the introduction of virus-contaminated pollen into a DWV-free hive results in the production of virus-contaminated food, whose role in the development of infected bees from virus-free eggs has been experimentally demonstrated. The aim of this study was twofold: (i to ascertain the presence of DWV on pollen collected directly from flowers visited by honeybees and then quantify the viral load and (ii determine whether the virus associated with pollen is infective. The results of our investigation provide evidence that DWV is present on pollen sampled directly from visited flowers and that, following injection in individuals belonging to the pollinator species Apis mellifera, it is able to establish an active infection, as indicated by the presence of replicating virus in the head of the injected bees. We also provide the first indication that the pollinator species Osmia cornuta is susceptible to DWV infection.

  4. Mutants of the major ryegrass pollen allergen, Lol p 5, with reduced IgE-binding capacity: candidates for grass pollen-specific immunotherapy.

    Science.gov (United States)

    Swoboda, Ines; De Weerd, Nicole; Bhalla, Prem L; Niederberger, Verena; Sperr, W R; Valent, Peter; Kahlert, Helga; Fiebig, Helmut; Verdino, Petra; Keller, Walter; Ebner, Christof; Spitzauer, Susanne; Valenta, Rudolf; Singh, Mohan B

    2002-01-01

    More than 400 million individuals are sensitized to grass pollen allergens. Group 5 allergens represent the most potent grass pollen allergens recognized by more than 80 % of grass pollen allergic patients. The aim of our study was to reduce the allergenic activity of group 5 allergens for specific immunotherapy of grass pollen allergy. Based on B- and T-cell epitope mapping studies and on sequence comparison of group 5 allergens from different grasses, point mutations were introduced by site-directed mutagenesis in highly conserved sequence domains of Lol p 5, the group 5 allergen from ryegrass. We obtained Lol p 5 mutants with low IgE-binding capacity and reduced allergenic activity as determined by basophil histamine release and by skin prick testing in allergic patients. Circular dichroism analysis showed that these mutants exhibited an overall structural fold similar to the recombinant Lol p 5 wild-type allergen. In addition, Lol p 5 mutants retained the ability to induce proliferation of group 5 allergen-specific T cell lines and clones. Our results demonstrate that a few point mutations in the Lol p 5 sequence yield mutants with reduced allergenic activity that represent potential vaccine candidates for immunotherapy of grass pollen allergy.

  5. Modeling 3D conjugate heat and mass transfer for turbulent air drying of Chilean papaya in a direct contact dryer

    Science.gov (United States)

    Lemus-Mondaca, Roberto A.; Vega-Gálvez, Antonio; Zambra, Carlos E.; Moraga, Nelson O.

    2017-01-01

    A 3D model considering heat and mass transfer for food dehydration inside a direct contact dryer is studied. The k- ɛ model is used to describe turbulent air flow. The samples thermophysical properties as density, specific heat, and thermal conductivity are assumed to vary non-linearly with temperature. FVM, SIMPLE algorithm based on a FORTRAN code are used. Results unsteady velocity, temperature, moisture, kinetic energy and dissipation rate for the air flow are presented, whilst temperature and moisture values for the food also are presented. The validation procedure includes a comparison with experimental and numerical temperature and moisture content results obtained from experimental data, reaching a deviation 7-10 %. In addition, this turbulent k- ɛ model provided a better understanding of the transport phenomenon inside the dryer and sample.

  6. Direct correlation of charge transfer absorption with molecular donor:acceptor interfacial area via photothermal deflection spectroscopy

    KAUST Repository

    Domingo, Ester

    2015-04-09

    We show that the Charge Transfer (CT) absorption signal in bulk-heterojunction (BHJ) solar cell blends, measured by photothermal deflection spectroscopy (PDS), is directly proportional to the density of molecular donor/acceptor interfaces. Since the optical transitions from ground state to the interfacial CT state are weakly allowed at photon energies below the optical gap of both donor and acceptor, we can exploit the use of this sensitive linear absorption spectroscopy for such quantification. Moreover, we determine the absolute molar extinction coefficient of the CT transition for an archetypical polymer-fullerene interface. The latter is ~100 times lower than the extinction coefficient of the donor chromophore involved, allowing us to experimentally estimate the transition dipole moment (0.3 D) and the electronic coupling between ground state and CT state to be on the order of 30 meV.

  7. Direct detection of ligand binding to Sepharose-immobilised protein using saturation transfer double difference (STDD) NMR spectroscopy

    International Nuclear Information System (INIS)

    Haselhorst, Thomas; Muenster-Kuehnel, Anja K.; Oschlies, Melanie; Tiralongo, Joe; Gerardy-Schahn, Rita; Itzstein, Mark von

    2007-01-01

    We report an easy and direct application of 'Saturation Transfer Double Difference' (STDD) NMR spectroscopy to identify ligands that bind to a Sepharose-immobilised target protein. The model protein, cytidine 5'-monophosphate sialic acid (CMP-Sia) synthetase, was expressed as a Strep-Tag II fusion protein and immobilised on Strep-Tactin Sepharose. STD NMR experiments of the protein-enriched Sepharose matrix in the presence of a binding ligand (cytidine 5'-triphosphate, CTP) and a non-binding ligand (α/β-glucose) clearly show that CTP binds to the immobilised enzyme, whereas glucose has no affinity. This approach has three major advantages: (a) only low quantities of protein are required, (b) no specialised NMR technology or the application of additional data analysis by non-routine methods is required, and (c) easy multiple use of the immobilised protein is available

  8. Enhancement of methanogenesis via direct interspecies electron transfer between Geobacteraceae and Methanosaetaceae conducted by granular activated carbon.

    Science.gov (United States)

    Zhang, Shuo; Chang, Jiali; Lin, Chao; Pan, Yiran; Cui, Kangping; Zhang, Xiaoyuan; Liang, Peng; Huang, Xia

    2017-12-01

    To understand how granular activated carbon (GAC) promotes methanogenesis, batch tests of CH 4 production potential in anaerobic serum bottles with addition of GAC or not were conducted. Tests showed that GAC promoted methanogenesis remarkably, but the non-conductive zeolite did not. The qPCR demonstrated that the biomass on GAC contributed little to the promotion. High-throughput sequencing data implied that promotion was related with direct interspecies electron transfer between Geobacteraceae and Methanosaetaceae. According to the c-type cytochromes (c-Cyts) response to the supplement of GAC, it was speculated that GAC may play the role of c-Cyts' substitution. In the undefined cultures, the phenomenon that c-Cyts were repressed by GAC was first observed. This research provided new evidence to microbial mechanism of promoting methanogenesis via GAC. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Direct electron transfer of Cytochrome c at mono-dispersed and negatively charged perylene-graphene matrix.

    Science.gov (United States)

    Zhang, Nan; Lv, Xiangyu; Ma, Weiguang; Hu, Yuwei; Li, Fenghua; Han, Dongxue; Niu, Li

    2013-03-30

    Mono-dispersed 3,4,9,10-perylene tetracarboxylic acid (PTCA) functionalized graphene sheets (PTCA-graphene) were fabricated by a chemical route and dispersed well in aqueous solution. PTCA-graphene with plenty of -COOH groups as electrostatic absorbing sites were beneficial to the loading of Cytochrome c (Cyt c). Cyt c, which was tightly immobilized on the PTCA-graphene modified glassy carbon electrode, maintained its natural conformation. Direct electron transfer of Cyt c and the electro-catalytic activity towards the reduction of H2O2 were also achieved. It has been substantiated that PTCA-graphene is a preferable biocompatible matrix for Cyt c. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Scrap tyre recycling process with molten zinc as direct heat transfer and solids separation fluid: A new reactor concept.

    Science.gov (United States)

    Riedewald, Frank; Goode, Kieran; Sexton, Aidan; Sousa-Gallagher, Maria J

    2016-01-01

    Every year about 1.5 billion tyres are discarded worldwide representing a large amount of solid waste, but also a largely untapped source of raw materials. The objective of the method was to prove the concept of a novel scrap tyre recycling process which uses molten zinc as the direct heat transfer fluid and, simultaneously, uses this media to separate the solids products (i.e. steel and rCB) in a sink-float separation at an operating temperature of 450-470 °C. This methodology involved: •construction of the laboratory scale batch reactor,•separation of floating rCB from the zinc,•recovery of the steel from the bottom of the reactor following pyrolysis.

  11. Reactor Meltdown: Critical Zone Processes In Siliciclastics Unlikely To Be Directly Transferable To Carbonates

    Science.gov (United States)

    Gulley, J. D.; Cohen, M. J.; Kramer, M. G.; Martin, J. B.; Graham, W. D.

    2013-12-01

    member of hydraulic and chemical heterogeneity that has no direct counterpart siliciclastic systems, these large voids provide easily accessible laboratories to investigate processes in carbonate critical zones, and how they differ from standard siliciclastic models of critical zones.

  12. Dinitrogen fixation by legume shade trees and direct transfer of fixed N to associated cacao in a tropical agroforestry system.

    Science.gov (United States)

    Nygren, Pekka; Leblanc, Humberto A

    2015-02-01

    Natural abundance of (15)N (δ (15)N) was determined in bulk soil, rhizospheric soil and vegetation in an organically managed cacao (Theobroma cacao L.) plantation with Inga edulis Mart. legume trees (inga) as the principal shade for studying the nitrogen (N) cycle in the system. Cacao without contact with legumes in an adjacent plantation was used as the reference for N2 fixation and direct N transfer calculations. Bulk and rhizospheric soils contained 72 and 20%, respectively, of whole- system N. No vegetation effect on δ (15)N in rhizospheric soil was detected, probably due to the high native soil N pool. Fine roots of the cacaos associated with inga contained ∼35% of N fixed from the atmosphere (Nf) out of the total N. Leaves of all species had significantly higher δ (15)N than fine roots. Twenty percent of system Nf was found in cacao suggesting direct N transfer from inga via a common mycelial network of mycorrhizal fungi or recycling of N-rich root exudates of inga. Inga had accumulated 98 kg [Nf] ha(-1) during the 14-year history of the plantation. The conservative estimate of current N2 fixation rate was 41 kg [Nf] ha(-1) year(-1) based on inga biomass only and 50 kg [Nf] ha(-1) year(-1) based on inga and associated trees. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  13. Insights into the immune manipulation mechanisms of pollen allergens by protein domain profiling.

    Science.gov (United States)

    Patel, Seema; Rani, Aruna; Goyal, Arun

    2017-10-01

    Plant pollens are airborne allergens, as their inhalation causes immune activation, leading to rhinitis, conjunctivitis, sinusitis and oral allergy syndrome. A myriad of pollen proteins belonging to profilin, expansin, polygalacturonase, glucan endoglucosidase, pectin esterase, and lipid transfer protein class have been identified. In the present in silico study, the protein domains of fifteen pollen sequences were extracted from the UniProt database and submitted to the interactive web tool SMART (Simple Modular Architecture Research Tool), for finding the protein domain profiles. Analysis of the data based on custom-made scripts revealed the conservation of pathogenic domains such as OmpH, PROF, PreSET, Bet_v_1, Cpl-7 and GAS2. Further, the retention of critical domains like CHASE2, Galanin, Dak2, DALR_1, HAMP, PWI, EFh, Excalibur, CT, PbH1, HELICc, and Kelch in pollen proteins, much like cockroach allergens and lethal viruses (such as HIV, HCV, Ebola, Dengue and Zika) was observed. Based on the shared motifs in proteins of taxonomicall-ydispersed organisms, it can be hypothesized that allergens and pathogens manipulate the human immune system in a similar manner. Allergens, being inanimate, cannot replicate in human body, and are neutralized by immune system. But, when the allergens are unremitting, the immune system becomes persistently hyper-sensitized, creating an inflammatory milieu. This study is expected to contribute to the understanding of pollen allergenicity and pathogenicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. A pollen-specific RALF from tomato that regulates pollen tube elongation.

    Science.gov (United States)

    Covey, Paul A; Subbaiah, Chalivendra C; Parsons, Ronald L; Pearce, Gregory; Lay, Fung T; Anderson, Marilyn A; Ryan, Clarence A; Bedinger, Patricia A

    2010-06-01

    Rapid Alkalinization Factors (RALFs) are plant peptides that rapidly increase the pH of plant suspension cell culture medium and inhibit root growth. A pollen-specific tomato (Solanum lycopersicum) RALF (SlPRALF) has been identified. The SlPRALF gene encodes a preproprotein that appears to be processed and released from the pollen tube as an active peptide. A synthetic SlPRALF peptide based on the putative active peptide did not affect pollen hydration or viability but inhibited the elongation of normal pollen tubes in an in vitro growth system. Inhibitory effects of SlPRALF were detectable at concentrations as low as 10 nm, and complete inhibition was observed at 1 mum peptide. At least 10-fold higher levels of alkSlPRALF, which lacks disulfide bonds, were required to see similar effects. A greater effect of peptide was observed in low-pH-buffered medium. Inhibition of pollen tube elongation was reversible if peptide was removed within 15 min of exposure. Addition of 100 nm SlPRALF to actively growing pollen tubes inhibited further elongation until tubes were 40 to 60 mum in length, after which pollen tubes became resistant to the peptide. The onset of resistance correlated with the timing of the exit of the male germ unit from the pollen grain into the tube. Thus, exogenous SlPRALF acts as a negative regulator of pollen tube elongation within a specific developmental window.

  15. INSITU BLOTTING - A NOVEL METHOD FOR DIRECT TRANSFER OF NATIVE PROTEINS FROM SECTIONED TISSUE TO BLOTTING MEMBRANE - PROCEDURE AND SOME APPLICATIONS

    NARCIS (Netherlands)

    OKABE, M; NYAKAS, C; BUWALDA, B; LUITEN, PGM

    We describe a novel technique for direct transfer of native proteins from unfixed frozen tissue sections to an immobilizing matrix, e.g., nitrocellulose, polyvinyliden difluoride, or positively charged nylon membranes. Proteins are directly blotted onto the membrane, providing optimal accessibility

  16. The effect of geographical and climatic properties on grass pollen and Phl p 5 allergen release

    Science.gov (United States)

    Alan, Şenol; Şahin, Aydan Acar; Sarışahin, Tuğba; Şahin, Serap; Kaplan, Ayşe; Pınar, Nur Münevver

    2018-04-01

    The Poaceae family, including grasses, comprises several cosmopolitan and allergenic species. The aim of this study was to determine the correlations between Poaceae pollen and Phl p 5 allergen concentrations in two cities with different geographical and climatic properties in Turkey. Pollen were collected from Burkard traps in Ankara and Zonguldak. Phl p 5 sampling was carried out between March and October in both 2015 and 2016 using a BGI900 Cascade High Volume Air Sampler (900 L/min.). The concentrations of Phl p 5 were measured by the enzyme-linked immunosorbent assay (ELISA) technique. The annual sum of Poaceae pollen (pollen index) during 2015-2016 was 5454 in Ankara and 4142 in Zonguldak. The total Phl p 5 concentration was 1309 pg/m3 in Zonguldak, whereas it was 8181 pg/m3 in Ankara over 2 years. About 90% of the allergen was found in the fraction with particulate matter (PM) > 10 μm in both cities. It was found that the main meteorological parameter which affected pollen and Phl p 5 was temperature in both stations. Rainfall was also found to be important for Zonguldak, due to its climatic and geographic properties. Lastly, we suggest that the primary wind direction, which is from the south of Zonguldak, could have a `drift effect' for allergens because of the airborne pollen concentrations and the dates on which the allergen is released into the atmosphere. The wind direction may be an important factor in the distribution of allergen and pollen grains in stations, especially those with a hilly topography.

  17. Loss of the Arabidopsis thaliana P4-ATPases ALA6 and ALA7 Impairs Pollen Fitness and Alters the Pollen Tube Plasma Membrane

    Directory of Open Access Journals (Sweden)

    Stephen C McDowell

    2015-04-01

    Full Text Available Members of the P4 subfamily of P-type ATPases are thought to create and maintain lipid asymmetry in biological membranes by flipping specific lipids between membrane leaflets. In Arabidopsis, 7 of the 12 Aminophospholipid ATPase (ALA family members are expressed in pollen. Here we show that double knockout of ALA6 and ALA7 (ala6/7 results in siliques with a ~2-fold reduction in seed set with a high frequency of empty seed positions near the bottom. Seed set was reduced to near zero when plants were grown under a hot/cold temperature stress. Reciprocal crosses indicate that the ala6/7 reproductive deficiencies are due to a defect related to pollen transmission. In-vitro growth assays provide evidence that that ala6/7 pollen tubes are short and slow, with ~2-fold reductions in both maximal growth rate and overall length relative to wild-type. Outcrosses show that when ala6/7 pollen are in competition with wild-type pollen, they have a near 0% success rate in fertilizing ovules near the bottom of the pistil, consistent with ala6/7 pollen having short and slow growth defects. The ala6/7 phenotypes were rescued by the expression of either an ALA6-YFP or GFP-ALA6 fusion protein, which showed localization to both the plasma membrane and highly-mobile endomembrane structures. A mass spectrometry analysis of mature pollen grains revealed significant differences between ala6/7 and wild-type, both in the relative abundance of lipid classes and in the average number of double bonds present in acyl side chains. A change in the properties of the ala6/7 plasma membrane was also indicated by a ~10-fold reduction of labeling by lipophilic FM-dyes relative to wild-type. Together, these results indicate that ALA6 and ALA7 provide redundant activities that function to directly or indirectly change the distribution and abundance lipids in pollen, and support a model in which ALA6 and ALA7 are critical for pollen fitness under normal and temperature-stress conditions.

  18. Next generation immunotherapy for tree pollen allergies.

    Science.gov (United States)

    Su, Yan; Romeu-Bonilla, Eliezer; Heiland, Teri

    2017-10-03

    Tree pollen induced allergies are one of the major medical and public health burdens in the industrialized world. Allergen-Specific Immunotherapy (AIT) through subcutaneous injection or sublingual delivery is the only approved therapy with curative potential to pollen induced allergies. AIT often is associated with severe side effects and requires long-term treatment. Safer, more effective and convenient allergen specific immunotherapies remain an unmet need. In this review article, we discuss the current progress in applying protein and peptide-based approaches and DNA vaccines to the clinical challenges posed by tree pollen allergies through the lens of preclinical animal models and clinical trials, with an emphasis on the birch and Japanese red cedar pollen induced allergies.

  19. Pollen flora of pakistan-lxxi. rosaceae

    International Nuclear Information System (INIS)

    Perveen, A.; Qaiser, M.

    2014-01-01

    Pollen morphology of 50 species representing 17 genera of the family Rosaceae i.e., Alchemilla, Argimonia, Cotoneaster, Crataegus, Duchesnea, Fragaria, Eriybotyra, Filipandula, Geum, Malus, Prunus, Potentilla, Pyrus , Rosa, Sibbaldia, Sorbaria and Sorbus has been studied from Pakistan by light and scanning electron microscope. Pollen grains are usually free, radially symmetrical, isopolar, prolate-spheroidal to subprolate or oblate-spheroidal rarely perprolate, tricolporate rarely tricolpate. Tectum mostly coarsely-finely striate, rarely striate-rugulate, scabrate or spinulose often reticulate. Rosaceae is more or less eurypalynous family. Significant variation is found in P/E ratio, shape and exine ornamentation and on the basis of these characters family has been divided into seven pollen types viz., Agrimonia eupatoria-type, Alchemilla ypsilotoma-type, Cotoneaster affinis-type, Fragaria nubicola-type, Geum roylei-type, Malus pumila-type, Potentilla pamirica-type. Pollen data is useful at specific and generic level. (author)

  20. Pollen-projektiga Rootsis / Lembit Jakobson

    Index Scriptorium Estoniae

    Jakobson, Lembit

    2009-01-01

    Avastusõppe projektist "Pollen" Eesti (2006-2009) mille eesmärk on kõiki lapsi kaasav uurimisõpe. Kevadisel koolivaheajal tutvus kümmekond Eesti õpetajat uurimisõppega Stockholmi kahes algkoolis

  1. Pollen as indicator of radionuclide pollution

    International Nuclear Information System (INIS)

    Kirkham, M.B.; Corey, J.C.

    1977-01-01

    To assess hazards of radioactivity in the environment, agricultural scientists must identify plant and animal species which can be used as biological indicators of radionuclide contamination. In this experiments, the pollen-bee-honey system was chosen to study movement of radioactive elements in the plant-animal-man food chain. Pollen, bees, and honey were collected from different locations at a nuclear facility in South Carolina. They were analyzed for nine radionuclides and 22 stable elements. The results showed that pollen is a more sensitive indicator of pollution than bees or honey. If pollen-monitoring shows that an area has become polluted, hives and other sources of human and animal food should not be placed in the region until it is no longer contaminated. (author)

  2. Juniper Pollen Hotspots in the Southwest

    Science.gov (United States)

    Bunderson, L. D.; VandeWater, P.; Luvall, J.; Levetin, E.

    2013-01-01

    Rationale: Juniperus pollen is a major allergen in Texas, Oklahoma, and New Mexico. While the bulk of pollen may be released in rural areas, large amounts of pollen can be transported to urban areas. Major juniper species in the region include: Juniperus ashei, J. virginiana, J. pinchotii, and J. monosperma. Pollen release is virtually continuous beginning in late September with J. pinchotii and ending in May with J. monosperma. Urban areas in the region were evaluated for the potential of overlapping seasons in order to inform sensitive individuals. Methods: Burkard volumetric pollen traps were established for two consecutive spring seasons at 6 sites in northern New Mexico and 6 sites for two consecutive winter and fall seasons in Texas and Oklahoma Standard methods were used in the preparation and analysis of slides. Results: The Dallas-Fort Worth Metroplex is home to over 6 million people. It is adjacent to populations of J. pinchotii, J. virginiana, and J. ashei. Peak concentration near Dallas for J. ashei in 2011 was 5891 pollen grains/m3 in January 7th. The peak date for J. pinchotii at an upwind sampling location in San Marcos, TX was November 1, 2010 and peak for J. virginiana at a nearby station in Tulsa, OK was November 1, 2010 and peak for J. virginiana at a nearby station in Tulsa, OK was February 20, 2011. Amarillo, TX is adjacent to J. pinchotii, J. ashei, and J. monosperma populations and may be subject to juniper pollen from September through May. Conclusions: Considering the overlapping distributions of juniper trees and the overlapping temporal release of pollen, sensitive patients may benefit from avoiding hotspots.

  3. Direct electron transfer and biosensing of glucose oxidase immobilized at multiwalled carbon nanotube-alumina-coated silica modified electrode

    International Nuclear Information System (INIS)

    Wu, Wei-Che; Huang, Jian-Lung; Tsai, Yu-Chen

    2012-01-01

    Investigations are reported regarding the direct electrochemical performance of glucose oxidase (GOD) immobilized on a film of multiwalled carbon nanotube-alumina-coated silica (MWCNT-ACS). The surface morphology of the GOD/MWCNT-ACS nanobiocomposite is characterized by scanning electron microscopy. In cyclic voltammetric response, the immobilized GOD displays a pair of well-defined redox peaks, with a formal potential (E°′) of − 0.466 V versus Ag/AgCl in a 0.1 M phosphate buffer solution (pH 7.5) at a scan rate of 0.05 V s −1 ; also the electrochemical response indicates a surface-controlled electrode process. The dependence of formal potential on solution pH indicates that the direct electron transfer reaction of GOD is a reversible two-electron coupled with a two-proton electrochemical reaction process. The glucose biosensor based on the GOD/MWCNT-ACS nanobiocomposite shows a sensitivity of 0.127 A M −1 cm −2 and an apparent Michaelis–Menten constant of 0.5 mM. Furthermore, the prepared biosensor exhibits excellent anti-interference ability to the commonly co-existed uric acid and ascorbic acid. - Highlights: ► A film composed of MWCNT-ACS was used for biosensor application. ► High sensitivity and good selectivity were obtained for the detection of glucose. ► This approach is potential for fabrication of mediator-free biosensor.

  4. Ragweed (Ambrosia) pollen source inventory for Austria.

    Science.gov (United States)

    Karrer, G; Skjøth, C A; Šikoparija, B; Smith, M; Berger, U; Essl, F

    2015-08-01

    This study improves the spatial coverage of top-down Ambrosia pollen source inventories for Europe by expanding the methodology to Austria, a country that is challenging in terms of topography and the distribution of ragweed plants. The inventory combines annual ragweed pollen counts from 19 pollen-monitoring stations in Austria (2004-2013), 657 geographical observations of Ambrosia plants, a Digital Elevation Model (DEM), local knowledge of ragweed ecology and CORINE land cover information from the source area. The highest mean annual ragweed pollen concentrations were generally recorded in the East of Austria where the highest densities of possible growth habitats for Ambrosia were situated. Approximately 99% of all observations of Ambrosia populations were below 745m. The European infection level varies from 0.1% at Freistadt in Northern Austria to 12.8% at Rosalia in Eastern Austria. More top-down Ambrosia pollen source inventories are required for other parts of Europe. A method for constructing top-down pollen source inventories for invasive ragweed plants in Austria, a country that is challenging in terms of topography and ragweed distribution. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

  5. Influence of pollen nutrition on honey bee health: do pollen quality and diversity matter?

    Science.gov (United States)

    Di Pasquale, Garance; Salignon, Marion; Le Conte, Yves; Belzunces, Luc P; Decourtye, Axel; Kretzschmar, André; Suchail, Séverine; Brunet, Jean-Luc; Alaux, Cédric

    2013-01-01

    Honey bee colonies are highly dependent upon the availability of floral resources from which they get the nutrients (notably pollen) necessary to their development and survival. However, foraging areas are currently affected by the intensification of agriculture and landscape alteration. Bees are therefore confronted to disparities in time and space of floral resource abundance, type and diversity, which might provide inadequate nutrition and endanger colonies. The beneficial influence of pollen availability on bee health is well-established but whether quality and diversity of pollen diets can modify bee health remains largely unknown. We therefore tested the influence of pollen diet quality (different monofloral pollens) and diversity (polyfloral pollen diet) on the physiology of young nurse bees, which have a distinct nutritional physiology (e.g. hypopharyngeal gland development and vitellogenin level), and on the tolerance to the microsporidian parasite Nosemaceranae by measuring bee survival and the activity of different enzymes potentially involved in bee health and defense response (glutathione-S-transferase (detoxification), phenoloxidase (immunity) and alkaline phosphatase (metabolism)). We found that both nurse bee physiology and the tolerance to the parasite were affected by pollen quality. Pollen diet diversity had no effect on the nurse bee physiology and the survival of healthy bees. However, when parasitized, bees fed with the polyfloral blend lived longer than bees fed with monofloral pollens, excepted for the protein-richest monofloral pollen. Furthermore, the survival was positively correlated to alkaline phosphatase activity in healthy bees and to phenoloxydase activities in infected bees. Our results support the idea that both the quality and diversity (in a specific context) of pollen can shape bee physiology and might help to better understand the influence of agriculture and land-use intensification on bee nutrition and health.

  6. Influence of pollen nutrition on honey bee health: do pollen quality and diversity matter?

    Directory of Open Access Journals (Sweden)

    Garance Di Pasquale

    Full Text Available Honey bee colonies are highly dependent upon the availability of floral resources from which they get the nutrients (notably pollen necessary to their development and survival. However, foraging areas are currently affected by the intensification of agriculture and landscape alteration. Bees are therefore confronted to disparities in time and space of floral resource abundance, type and diversity, which might provide inadequate nutrition and endanger colonies. The beneficial influence of pollen availability on bee health is well-established but whether quality and diversity of pollen diets can modify bee health remains largely unknown. We therefore tested the influence of pollen diet quality (different monofloral pollens and diversity (polyfloral pollen diet on the physiology of young nurse bees, which have a distinct nutritional physiology (e.g. hypopharyngeal gland development and vitellogenin level, and on the tolerance to the microsporidian parasite Nosemaceranae by measuring bee survival and the activity of different enzymes potentially involved in bee health and defense response (glutathione-S-transferase (detoxification, phenoloxidase (immunity and alkaline phosphatase (metabolism. We found that both nurse bee physiology and the tolerance to the parasite were affected by pollen quality. Pollen diet diversity had no effect on the nurse bee physiology and the survival of healthy bees. However, when parasitized, bees fed with the polyfloral blend lived longer than bees fed with monofloral pollens, excepted for the protein-richest monofloral pollen. Furthermore, the survival was positively correlated to alkaline phosphatase activity in healthy bees and to phenoloxydase activities in infected bees. Our results support the idea that both the quality and diversity (in a specific context of pollen can shape bee physiology and might help to better understand the influence of agriculture and land-use intensification on bee nutrition and health.

  7. Developmental evolution of flowering plant pollen tube cell walls: callose synthase (CalS gene expression patterns

    Directory of Open Access Journals (Sweden)

    Abercrombie Jason M

    2011-07-01

    Full Text Available Abstract Background A number of innovations underlie the origin of rapid reproductive cycles in angiosperms. A critical early step involved the modification of an ancestrally short and slow-growing pollen tube for faster and longer distance transport of sperm to egg. Associated with this shift are the predominantly callose (1,3-β-glucan walls and septae (callose plugs of angiosperm pollen tubes. Callose synthesis is mediated by callose synthase (CalS. Of 12 CalS gene family members in Arabidopsis, only one (CalS5 has been directly linked to pollen tube callose. CalS5 orthologues are present in several monocot and eudicot genomes, but little is known about the evolutionary origin of CalS5 or what its ancestral function may have been. Results We investigated expression of CalS in pollen and pollen tubes of selected non-flowering seed plants (gymnosperms and angiosperms within lineages that diverged below the monocot/eudicot node. First, we determined the nearly full length coding sequence of a CalS5 orthologue from Cabomba caroliniana (CcCalS5 (Nymphaeales. Semi-quantitative RT-PCR demonstrated low CcCalS5 expression within several vegetative tissues, but strong expression in mature pollen. CalS transcripts were detected in pollen tubes of several species within Nymphaeales and Austrobaileyales, and comparative analyses with a phylogenetically diverse group of sequenced genomes indicated homology to CalS5. We also report in silico evidence of a putative CalS5 orthologue from Amborella. Among gymnosperms, CalS5 transcripts were recovered from germinating pollen of Gnetum and Ginkgo, but a novel CalS paralog was instead amplified from germinating pollen of Pinus taeda. Conclusion The finding that CalS5 is the predominant callose synthase in pollen tubes of both early-diverging and model system angiosperms is an indicator of the homology of their novel callosic pollen tube walls and callose plugs. The data suggest that CalS5 had transient expression

  8. Flowering and the Pollen Fertility in Iranian Garlic Clones

    Directory of Open Access Journals (Sweden)

    A. R. Abbasifar

    2015-06-01

    Full Text Available Garlic (Allium sativum L. cannot produce seed because it is a sterile plant. For studying bolting and determination of pollen fertility, 68 Iranian garlic clones were gathered from different parts of Iran and evaluated in Research Field of Horticultural Department, Faculty of Agriculture, Bu-Ali Sina University in 2010-2011 and 2011-2012. For determining the pollen fertility, some tests including specific RAPD marker, pollen germination, pollen viability detection using acetocarmine and in vitro culture of ovules and fruits were used. Results showed that 37 of Iranian garlic clones could produce scape and inflorescence. The percentage range of pollen stained with acetocarmine was from 0.5 up to 20 percent showing infertility of pollens. Lack of two markers (OPJ121300 and OPJ121700 and pollen tube growth proved the infertility of garlic clones pollen. Fruits and embryo sac were alive for more than two months, showing their potential for producing seeds following pollination with fertile pollens.

  9. Comparative long-term trend analysis of daily weather conditions with daily pollen concentrations in Brussels, Belgium

    Science.gov (United States)

    Bruffaerts, Nicolas; De Smedt, Tom; Delcloo, Andy; Simons, Koen; Hoebeke, Lucie; Verstraeten, Caroline; Van Nieuwenhuyse, An; Packeu, Ann; Hendrickx, Marijke

    2018-03-01

    A clear rise in seasonal and annual temperatures, a gradual increase of total radiation, and a relative trend of change in seasonal precipitation have been observed for the last four decades in Brussels (Belgium). These local modifications may have a direct and indirect public health impact by altering the timing and intensity of allergenic pollen seasons. In this study, we assessed the statistical correlations (Spearman's test) between pollen concentration and meteorological conditions by using long-term daily datasets of 11 pollen types (8 trees and 3 herbaceous plants) and 10 meteorological parameters observed in Brussels between 1982 and 2015. Furthermore, we analyzed the rate of change in the annual cycle of the same selected pollen types by the Mann-Kendall test. We revealed an overall trend of increase in daily airborne tree pollen (except for the European beech tree) and an overall trend of decrease in daily airborne pollen from herbaceous plants (except for Urticaceae). These results revealed an earlier onset of the flowering period for birch, oak, ash, plane, grasses, and Urticaceae. Finally, the rates of change in pollen annual cycles were shown to be associated with the rates of change in the annual cycles of several meteorological parameters such as temperature, radiation, humidity, and rainfall.

  10. Pollen as a possible pathway for the dissemination of Pseudomonas syringae pv. actinide and bacterial canker of kiwifruit

    Directory of Open Access Journals (Sweden)

    Rodanthi TONTOU

    2014-09-01

    Full Text Available Pollen collected in a kiwifruit orchard with symptoms of bacterial canker and naturally contaminated by Pseudomonas syringae pv. actinidiae (Psa, was used to pollinate an experimental orchard, in order to confirm its role, under commercial orchard conditions, in disseminating the pathogen and, possibly, contributing to disease spread. A pollen lot, certified free from Psa, was used with the same methods as a control. Two pollination techniques were used: dusting (dry pollen and spraying (pollen suspension in water. The orchard was monitored during 2 years from experimental pollination, with regular sampling of flowers, fruits, leaves, and vines, to check for Psa as an epiphyte or endophyte, and for bacterial canker symptoms. Psa was recovered from flowers, fruitlets and leaves during the first season, mainly in plots where contaminated pollen had been sprayed in water suspension. From early August until harvesting time (mid-October, Psa detection was possible only on leaves. No symptoms developed during the first season after pollination. No endophytic Psa was detected in pruned vines in the following winter. During the second season, detection and isolation of Psa was erratic, but direct isolation was achieved from four plots. During the second season after pollination, typical leaf symptoms were observed on a few vines, and Psa was isolated and identified. Our results suggest that Psa could be disseminated via contaminated kiwifruit pollen as a pathway for spread of bacterial canker. However, further pollination experiments are needed to establish, beyond any doubt, whether contaminated pollen may contribute to possible disease outbreaks.

  11. Comparative long-term trend analysis of daily weather conditions with daily pollen concentrations in Brussels, Belgium.

    Science.gov (United States)

    Bruffaerts, Nicolas; De Smedt, Tom; Delcloo, Andy; Simons, Koen; Hoebeke, Lucie; Verstraeten, Caroline; Van Nieuwenhuyse, An; Packeu, Ann; Hendrickx, Marijke

    2018-03-01

    A clear rise in seasonal and annual temperatures, a gradual increase of total radiation, and a relative trend of change in seasonal precipitation have been observed for the last four decades in Brussels (Belgium). These local modifications may have a direct and indirect public health impact by altering the timing and intensity of allergenic pollen seasons. In this study, we assessed the statistical correlations (Spearman's test) between pollen concentration and meteorological conditions by using long-term daily datasets of 11 pollen types (8 trees and 3 herbaceous plants) and 10 meteorological parameters observed in Brussels between 1982 and 2015. Furthermore, we analyzed the rate of change in the annual cycle of the same selected pollen types by the Mann-Kendall test. We revealed an overall trend of increase in daily airborne tree pollen (except for the European beech tree) and an overall trend of decrease in daily airborne pollen from herbaceous plants (except for Urticaceae). These results revealed an earlier onset of the flowering period for birch, oak, ash, plane, grasses, and Urticaceae. Finally, the rates of change in pollen annual cycles were shown to be associated with the rates of change in the annual cycles of several meteorological parameters such as temperature, radiation, humidity, and rainfall.

  12. Marker allergens of weed pollen - basic considerations and diagnostic benefits in the clinical routine: Part 16 of the Series Molecular Allergology.

    Science.gov (United States)

    Stemeseder, Teresa; Hemmer, Wolfgang; Hawranek, Thomas; Gadermaier, Gabriele

    The term weed is referring to plants used as culinary herbs and medicinal plants as well as ecologically adaptive and invasive segetal plants. In Europe, pollen of ragweed, mugwort, English plantain and pellitory are the main elicitors of weed pollen allergies. Presently, 35 weed pollen allergens have been identified. The most relevant belong to the protein families of pectate lyases, defensin-like proteins, non-specific lipid transfer proteins, and Ole e 1-like proteins. The sensitization frequency depends on geographic regions and might affect more than 50 % of pollen allergic patients in distinct regions. Due to overlapping flowering seasons, similar habitats, polysensitizations and cross-reactive (pan)-allergens, it is difficult to diagnose genuine weed pollen sensitization using pollen extracts. Marker allergens for component-resolved diagnostics are available for the important weed pollen. These are Amb a 1 (ragweed), Art v 1 (mugwort), Pla l 1 (English plantain) and Par j 2 (pellitory). Molecule-based approaches can be used to identify the primary sensitizer and thus enable selection of the appropriate weed pollen extracts for allergen immunotherapy.

  13. Defective Pollen Wall 2 ( DPW2 ) Encodes an Acyl Transferase Required for Rice Pollen Development

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Dawei [Shanghai Jiao Tong Univ. (China). Joint International Research Lab. of Metabolic and Developmental Sciences; Shi, Jianxin [Shanghai Jiao Tong Univ. (China). Joint International Research Lab. of Metabolic and Developmental Sciences; Rautengarten, Carsten [Univ. of Melbourne (Australia). ARC Centre of Excellence in Plant Cell Walls; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint BioEnergy Inst. and Biological Systems and Engineering Division; Yang, Li [Shanghai Jiao Tong Univ. (China). Joint International Research Lab. of Metabolic and Developmental Sciences; Qian, Xiaoling [Shanghai Jiao Tong Univ. (China). Joint International Research Lab. of Metabolic and Developmental Sciences; Uzair, Muhammad [Shanghai Jiao Tong Univ. (China). Joint International Research Lab. of Metabolic and Developmental Sciences; Zhu, Lu [Shanghai Jiao Tong Univ. (China). Joint International Research Lab. of Metabolic and Developmental Sciences; Luo, Qian [Shanghai Jiao Tong Univ. (China). Joint International Research Lab. of Metabolic and Developmental Sciences; An, Gynheung [Kyung Hee Univ., Yongin (Korea). Crop Biotech Inst.; Waßmann, Fritz [Univ. of Bonn (Germany). Inst. of Cellular and Molecular Botany; Schreiber, Lukas [Univ. of Bonn (Germany). Inst. of Cellular and Molecular Botany; Heazlewood, Joshua L. [Univ. of Melbourne (Australia). ARC Centre of Excellence in Plant Cell Walls; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint BioEnergy Inst. and Biological Systems and Engineering Division; Scheller, Henrik Vibe [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint BioEnergy Inst. and Biological Systems and Engineering Division; Univ. of California, Berkeley, CA (United States). Dept. of Plant and Microbial Biology; Hu, Jianping [Michigan State Univ., East Lansing, MI (United States). Dept. of Energy Plant Research Lab.; Zhang, Dabing [Shanghai Jiao Tong Univ. (China). Joint International Research Lab. of Metabolic and Developmental Sciences; Univ. of Adelaide, SA (Australia). School of Agriculture, Food and Wine; Liang, Wanqi [Shanghai Jiao Tong Univ. (China). Joint International Research Lab. of Metabolic and Developmental Sciences

    2016-05-31

    Aliphatic and aromatic lipids are both essential structural components of the plant cuticle, an important interface between the plant and environment. Although cross links between aromatic and aliphatic or other moieties are known to be associated with the formation of leaf cutin and root and seed suberin, the contribution of aromatic lipids to the biosynthesis of anther cuticles and pollen walls remains elusive. In this study, we characterized the rice (Oryza sativa) male sterile mutant, defective pollen wall 2 (dpw2), which showed an abnormal anther cuticle, a defective pollen wall, and complete male sterility. Compared with the wild type, dpw2 anthers have increased amounts of cutin and waxes and decreased levels of lipidic and phenolic compounds. DPW2 encodes a cytoplasmically localized BAHD acyltransferase. In vitro assays demonstrated that recombinant DPW2 specifically transfers hydroxycinnamic acid moieties, using v-hydroxy fatty acids as acyl acceptors and hydroxycinnamoyl-CoAs as acyl donors. Thus, The cytoplasmic hydroxycinnamoyl-CoA:v-hydroxy fatty acid transferase DPW2 plays a fundamental role in male reproduction via the biosynthesis of key components of the anther cuticle and pollen wall.

  14. Role of a non-ionic surfactant in direct electron transfer-type bioelectrocatalysis by fructose dehydrogenase

    International Nuclear Information System (INIS)

    Kawai, Shota; Yakushi, Toshiharu; Matsushita, Kazunobu; Kitazumi, Yuki; Shirai, Osamu; Kano, Kenji

    2015-01-01

    Highlights: • Addition of Triton ® X-100 (1%) completely quenches the FDH-catalyzed current at hydrophobic electrode, but causes only small competitive effect at hydrophilic electrode. • Quartz crystal microbalance measurements support the adsorption of FDH and Triton ® X-100 on both of the electrodes. • The surfactant forms a monolayer on the hydrophobic electrode and FDH adsorbs on the surfactant monolayer. • The surfactant forms a bilayer on the hydrophilic electrode and FDH is embedded in the bilayer to communicate with the electrode. - ABSTRACT: A heterotrimeric membrane-bound fructose dehydrogenase (FDH) from Gluconobacter japonicus NBRC3260 contains FAD in subunit I and three heme C moieties in subunit II as the redox centers, and is one of the direct electron transfer (DET)-type redox enzymes. FDH-catalyzed current density of fructose oxidation at hydrophilic mercaptoethanol (MEtOH)-modified Au electrode is much larger than that at hydrophobic mercaptoethane (MEtn)-modified Au electrode. Addition of a non-ionic surfactant Triton ® X-100 (1%) completely quenches the catalytic current at the MEtn-modified Au electrode, while only small competitive effect is observed at the MEtOH-modified Au electrode. Quartz crystal microbalance measurements support the adsorption of FDH and Triton ® X-100 on both of the modified electrodes. We propose a model to explain the phenomenon as follows. The surfactant forms a monolayer on the hydrophobic MEtn-modified electrode with strong hydrophobic interaction, and FDH adsorbs on the surface of the surfactant monolayer. The monolayer inhibits the electron transfer from FDH to the electrode. On the other hand, the surfactant forms a bilayer on the hydrophilic MEtOH-modified electrode. The interaction between the surfactant bilayer and the hydrophilic electrode is relatively weak so that FDH replaces the surfactant and is embedded in the bilayer to communicate electrochemically with the hydrophilic electrode

  15. Proton transfers in a channelrhodopsin-1 studied by Fourier transform infrared (FTIR) difference spectroscopy and site-directed mutagenesis.

    Science.gov (United States)

    Ogren, John I; Yi, Adrian; Mamaev, Sergey; Li, Hai; Spudich, John L; Rothschild, Kenneth J

    2015-05-15

    Channelrhodopsin-1 from the alga Chlamydomonas augustae (CaChR1) is a low-efficiency light-activated cation channel that exhibits properties useful for optogenetic applications such as a slow light inactivation and a red-shifted visible absorption maximum as compared with the more extensively studied channelrhodopsin-2 from Chlamydomonas reinhardtii (CrChR2). Previously, both resonance Raman and low-temperature FTIR difference spectroscopy revealed that unlike CrChR2, CaChR1 under our conditions exhibits an almost pure all-trans retinal composition in the unphotolyzed ground state and undergoes an all-trans to 13-cis isomerization during the primary phototransition typical of other microbial rhodopsins such as bacteriorhodopsin (BR). Here, we apply static and rapid-scan FTIR difference spectroscopy along with site-directed mutagenesis to characterize the proton transfer events occurring upon the formation of the long-lived conducting P2 (380) state of CaChR1. Assignment of carboxylic C=O stretch bands indicates that Asp-299 (homolog to Asp-212 in BR) becomes protonated and Asp-169 (homolog to Asp-85 in BR) undergoes a net change in hydrogen bonding relative to the unphotolyzed ground state of CaChR1. These data along with earlier FTIR measurements on the CaChR1 → P1 transition are consistent with a two-step proton relay mechanism that transfers a proton from Glu-169 to Asp-299 during the primary phototransition and from the Schiff base to Glu-169 during P2 (380) formation. The unusual charge neutrality of both Schiff base counterions in the P2 (380) conducting state suggests that these residues may function as part of a cation selective filter in the open channel state of CaChR1 as well as other low-efficiency ChRs. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. A novel transient wall heat transfer approach for the start-up of SI engines with gasoline direct injection

    Science.gov (United States)

    Lejsek, David; Kulzer, André; Hammer, Jürgen

    2010-11-01

    The introduction of CO2-reduction technologies like Start-Stop or the Hybrid-Powertrain and the worldwide stringent emission legislation require a detailed optimization of the engine start-up. The combustion concept development as well as the calibration of the engine control unit makes an explicit thermodynamic analysis of the combustion process during the start-up necessary. Initially, the well-known thermodynamic analysis of in-cylinder pressure at stationary condition was transmitted to the highly non-stationary engine start-up. For this running mode of the engine the current models for calculation of the transient wall heat fluxes were found to be misleading. With a fraction of nearly 45% of the burned fuel energy, the wall heat is very important for the calculation of energy balance and for the combustion process analysis. Based on the measurements of transient wall heat transfer densities during the start-up presented in a former work (Lejsek and Kulzer in Investigations on the transient wall heat transfer at start-up for SI engines with gasoline direct injection. SAE Paper), the paper describes the development of adaptations to the known correlations by Woschni (MTZ 31:491, 1970), Hohenberg (Experimentelle Erfassung der Wandwärme von Kolbenmotoren. TU Graz, Habil., 1980) and Bargende (Ein Gleichungsansatz zur Berechnung der instationären Wandwärmeverluste im Hochdruckteil von Ottomotoren. TH Darmstadt, PhD-Thesis, 1991) for the application during engine start-up. To demonstrate the high accuracy of the model, the results of the cyclic resolved thermodynamic analysis using the presented novel approaches were compared with the results of the measurements. It is shown, that the novel heat flux models for the engine start-up process gives a cyclic resolved thermodynamic analysis to optimize the engine start-up pretty efficient.

  17. De novo post-pollen mitosis II tobacco pollen tube transcriptome

    Czech Academy of Sciences Publication Activity Database

    Hafidh, Said; Breznenová, Katarína; Honys, David

    2012-01-01

    Roč. 7, č. 8 (2012), s. 918-921 ISSN 1559-2316 R&D Projects: GA ČR GPP501/11/P321; GA ČR GA522/09/0858 Institutional research plan: CEZ:AV0Z50380511 Keywords : de novo pollen tube transcriptome * male gametophyte development * pollen tube growth Subject RIV: ED - Physiology

  18. Storage and irradiation of Cucumis pollen and their influence on pollen vitality

    International Nuclear Information System (INIS)

    Oost, E.H.; Nijs, A.P.M. den

    1979-01-01

    In connection with an interspecific hybridization programme and a mentor pollen experiment in Cucumis, the optimal storage conditions and in vitro germination medium for both fresh and irradiated pollen of the cultivated cucumber and two wild African Cucumis species have been searched for. (Auth.)

  19. Pollen of Southeast Asian Alchornea (Euphorbiaceae), with an overview of the pollen fossil record

    NARCIS (Netherlands)

    Bulalacao, L.J.; Ham, van der R.W.J.M.

    2003-01-01

    In order to evaluate pollen morphological descriptions of Alchornea in the literature, which are almost completely based on African and American species, the pollen of eight Southeast Asian species of Alchornea was investigated, using light and scanning electron microscopy. Very little variation

  20. Pollen reconstructions, tree-rings and early climate data from Minnesota, USA: a cautionary tale of bias and signal attentuation

    Science.gov (United States)

    St-Jacques, J. M.; Cumming, B. F.; Smol, J. P.; Sauchyn, D.

    2015-12-01

    High-resolution proxy reconstructions are essential to assess the rate and magnitude of anthropogenic global warming. High-resolution pollen records are being critically examined for the production of accurate climate reconstructions of the last millennium, often as extensions of tree-ring records. Past climate inference from a sedimentary pollen record depends upon the stationarity of the pollen-climate relationship. However, humans have directly altered vegetation, and hence modern pollen deposition is a product of landscape disturbance and climate, unlike in the past with its dominance of climate-derived processes. This could cause serious bias in pollen reconstructions. In the US Midwest, direct human impacts have greatly altered the vegetation and pollen rain since Euro-American settlement in the mid-19th century. Using instrumental climate data from the early 1800s from Fort Snelling (Minnesota), we assessed the bias from the conventional method of inferring climate from pollen assemblages in comparison to a calibration set from pre-settlement pollen assemblages and the earliest instrumental climate data. The pre-settlement calibration set provides more accurate reconstructions of 19th century temperature than the modern set does. When both calibration sets are used to reconstruct temperatures since AD 1116 from a varve-dated pollen record from Lake Mina, Minnesota, the conventional method produces significant low-frequency (centennial-scale) signal attenuation and positive bias of 0.8-1.7 oC, resulting in an overestimation of Little Ice Age temperature and an underestimation of anthropogenic warming. We also compared the pollen-inferred moisture reconstruction to a four-century tree-ring-inferred moisture record from Minnesota and Dakotas, which shows that the tree-ring reconstruction is biased towards dry conditions and records wet periods relatively poorly, giving a false impression of regional aridity. The tree-ring chronology also suggests varve

  1. Concentrations of imidacloprid and thiamethoxam in pollen, nectar and leaves from seed-dressed cotton crops and their potential risk to honeybees (Apis mellifera L.).

    Science.gov (United States)

    Jiang, Jiangong; Ma, Dicheng; Zou, Nan; Yu, Xin; Zhang, Zhengqun; Liu, Feng; Mu, Wei

    2018-06-01

    Neonicotinoid insecticides (NIs) have recently been recognized as co-factors in the decline of honeybee colonies because most neonicotinoids are systemic and can transfer into the pollen and nectar of many pollinated crops. In this study, we collected pollen, nectar and leaves from a cotton crop treated with imidacloprid and thiamethoxam to measure the residue levels of these two NIs at different application doses during the flowering period. Then, the residual data were used to assess the risk posed by the systemic insecticides to honeybees following mandated methods published by the European Food Safety Authority (EFSA), and a highly toxic risk to honeybees was highlighted. Imidacloprid was found in both pollen and nectar samples, whereas thiamethoxam was found in 90% of pollen samples and over 60% of nectar samples. Analysis of the pollen and nectar revealed residual amounts of imidacloprid ranging from 1.61 to 64.58 ng g -1 in the pollen and from not detected (ND) to 1.769 ng g -1 in the nectar. By comparison, the thiamethoxam concentrations in pollen and nectar ranged from ND to 14.521 ng g -1 and from ND to 4.285 ng g -1 , respectively. The results of this study provide information on the transfer of two NIs from seed treatment to areas of the plant and provides an understanding of the potential exposure of the bee and other pollinators to systemic insecticides. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Two-peaked dose curves for irradiated pollen growth

    International Nuclear Information System (INIS)

    Andrejchenko, S.V.; Grodzinskij, D.M.

    1992-01-01

    The effect of γ-radiation on growth activity of bicellular pollen of hybrid petunia has been investigated. Irradiation of pollen with doses of 5 to 70 Gy increases the pollen tube growth in an artificial culture medium. As the radiation dose increases the germination ability of pollen gradually decreases and the mean pollen tube length shortens, which is accompanied by the suppression of the generative cell division into spermia and inhibition of the unscheduled incorporation of labelled thymidine into DNA. With radiation doses of 1200 to 1700 Gy some pollen tubes grow intensively. It is suggested that the phenomenon observed lays the basis for the gametic transformation

  3. Transport logistics in pollen tubes.

    Science.gov (United States)

    Chebli, Youssef; Kroeger, Jens; Geitmann, Anja

    2013-07-01

    Cellular organelles move within the cellular volume and the effect of the resulting drag forces on the liquid causes bulk movement in the cytosol. The movement of both organelles and cytosol leads to an overall motion pattern called cytoplasmic streaming or cyclosis. This streaming enables the active and passive transport of molecules and organelles between cellular compartments. Furthermore, the fusion and budding of vesicles with and from the plasma membrane (exo/endocytosis) allow for transport of material between the inside and the outside of the cell. In the pollen tube, cytoplasmic streaming and exo/endocytosis are very active and fulfill several different functions. In this review, we focus on the logistics of intracellular motion and transport processes as well as their biophysical underpinnings. We discuss various modeling attempts that have been performed to understand both long-distance shuttling and short-distance targeting of organelles. We show how the combination of mechanical and mathematical modeling with cell biological approaches has contributed to our understanding of intracellular transport logistics.

  4. Testing pollen of single and stacked insect-resistant Bt-maize on in vitro reared honey bee larvae.

    Science.gov (United States)

    Hendriksma, Harmen P; Härtel, Stephan; Steffan-Dewenter, Ingolf

    2011-01-01

    The ecologically and economic important honey bee (Apis mellifera) is a key non-target arthropod species in environmental risk assessment (ERA) of genetically modified (GM) crops. Honey bee larvae are directly exposed to transgenic products by the consumption of GM pollen. But most ERA studies only consider responses of adult bees, although Bt-proteins primarily affect the larval phases of target organisms. We adopted an in vitro larvae rearing system, to assess lethal and sublethal effects of Bt-pollen consumption in a standardized eco-toxicological bioassay. The effects of pollen from two Bt-maize cultivars, one expressing a single and the other a total of three Bt-proteins, on the survival and prepupae weight of honey bee larvae were analyzed. The control treatments included pollen from three non-transgenic maize varieties and of Heliconia rostrata. Three days old larvae were fed the realistic exposure dose of 2 mg pollen within the semi-artificial diet. The larvae were monitored over 120 h, until the prepupal stage, where larvae terminate feeding and growing. Neither single nor stacked Bt-maize pollen showed an adverse effect on larval survival and the prepupal weight. In contrast, feeding of H. rostrata pollen caused significant toxic effects. The results of this study indicate that pollen of the tested Bt-varieties does not harm the development of in vitro reared A. mellifera larvae. To sustain the ecosystem service of pollination, Bt-impact on A. mellifera should always be a crucial part of regulatory biosafety assessments. We suggest that our approach of feeding GM pollen on in vitro reared honey bee larvae is well suited of becoming a standard bioassay in regulatory risk assessments schemes of GM crops.

  5. Stable carbon isotope fractionation in pollen of Atlas cedar: first steps towards a new palaeoecological proxy for Northwest Africa

    Science.gov (United States)

    Bell, Benjamin; Fletcher, William; Ryan, Peter; Grant, Helen; Ilmen, Rachid

    2016-04-01

    Analysis of stable carbon isotopes can provide information on climate and the environmental conditions at different growth stages of the plant, both past and present. Carbon isotope discrimination in plant tissue is already well understood, and can be used as a drought stress indicator for semi-arid regions. Stable carbon isotope ratios measured directly on pollen provides the potential for the development of long-term environmental proxies (spanning thousands of years), as pollen is well preserved in the environment. Atlas Cedar (Cedrus atlantica Endl. Manetti ex Carrière), is an ideal test case to develop a pollen stable carbon isotope proxy. The tree grows across a wide altitudinal and climatic range and is extremely sensitive to moisture availability. The pollen is abundant, and easily identifiable to the species level in pollen analysis because different cedar species are geographically confined to different regions of the world. In 2015 we sampled 76 individual cedar trees across latitudinal, altitudinal and environmental gradients, highly focused on the Middle Atlas region of Morocco, with 25 additional samples from botanical gardens across Europe and the US to extend these gradients. Here, we report new stable carbon isotope data from pollen, leaf and stem wood from these samples with a view to assessing and quantifying species-specific fractionation effects associated with pollen production. The isotopic response of individual trees at local and wider geographical scales to altitude and climatic conditions is presented. This research forms part of an ongoing PhD project working to develop and calibrate a modern carbon isotope proxy in Atlas cedar pollen, which can ultimately be applied to fossil sequences and complement existing multi-proxy records (e.g. pollen analysis in lake sediments, tree-rings).

  6. Testing pollen of single and stacked insect-resistant Bt-maize on in vitro reared honey bee larvae.

    Directory of Open Access Journals (Sweden)

    Harmen P Hendriksma

    Full Text Available The ecologically and economic important honey bee (Apis mellifera is a key non-target arthropod species in environmental risk assessment (ERA of genetically modified (GM crops. Honey bee larvae are directly exposed to transgenic products by the consumption of GM pollen. But most ERA studies only consider responses of adult bees, although Bt-proteins primarily affect the larval phases of target organisms. We adopted an in vitro larvae rearing system, to assess lethal and sublethal effects of Bt-pollen consumption in a standardized eco-toxicological bioassay. The effects of pollen from two Bt-maize cultivars, one expressing a single and the other a total of three Bt-proteins, on the survival and prepupae weight of honey bee larvae were analyzed. The control treatments included pollen from three non-transgenic maize varieties and of Heliconia rostrata. Three days old larvae were fed the realistic exposure dose of 2 mg pollen within the semi-artificial diet. The larvae were monitored over 120 h, until the prepupal stage, where larvae terminate feeding and growing. Neither single nor stacked Bt-maize pollen showed an adverse effect on larval survival and the prepupal weight. In contrast, feeding of H. rostrata pollen caused significant toxic effects. The results of this study indicate that pollen of the tested Bt-varieties does not harm the development of in vitro reared A. mellifera larvae. To sustain the ecosystem service of pollination, Bt-impact on A. mellifera should always be a crucial part of regulatory biosafety assessments. We suggest that our approach of feeding GM pollen on in vitro reared honey bee larvae is well suited of becoming a standard bioassay in regulatory risk assessments schemes of GM crops.

  7. Testing Pollen of Single and Stacked Insect-Resistant Bt-Maize on In vitro Reared Honey Bee Larvae

    Science.gov (United States)

    Hendriksma, Harmen P.; Härtel, Stephan; Steffan-Dewenter, Ingolf

    2011-01-01

    The ecologically and economic important honey bee (Apis mellifera) is a key non-target arthropod species in environmental risk assessment (ERA) of genetically modified (GM) crops. Honey bee larvae are directly exposed to transgenic products by the consumption of GM pollen. But most ERA studies only consider responses of adult bees, although Bt-proteins primarily affect the larval phases of target organisms. We adopted an in vitro larvae rearing system, to assess lethal and sublethal effects of Bt-pollen consumption in a standardized eco-toxicological bioassay. The effects of pollen from two Bt-maize cultivars, one expressing a single and the other a total of three Bt-proteins, on the survival and prepupae weight of honey bee larvae were analyzed. The control treatments included pollen from three non-transgenic maize varieties and of Heliconia rostrata. Three days old larvae were fed the realistic exposure dose of 2 mg pollen within the semi-artificial diet. The larvae were monitored over 120 h, until the prepupal stage, where larvae terminate feeding and growing. Neither single nor stacked Bt-maize pollen showed an adverse effect on larval survival and the prepupal weight. In contrast, feeding of H. rostrata pollen caused significant toxic effects. The results of this study indicate that pollen of the tested Bt-varieties does not harm the development of in vitro reared A. mellifera larvae. To sustain the ecosystem service of pollination, Bt-impact on A. mellifera should always be a crucial part of regulatory biosafety assessments. We suggest that our approach of feeding GM pollen on in vitro reared honey bee larvae is well suited of becoming a standard bioassay in regulatory risk assessments schemes of GM crops. PMID:22194811

  8. Ozone affects pollen viability and NAD(P)H oxidase release from Ambrosia artemisiifolia pollen

    Energy Technology Data Exchange (ETDEWEB)

    Pasqualini, Stefania, E-mail: spas@unipg.it [Department of Applied Biology, University of Perugia, Perugia (Italy); Tedeschini, Emma; Frenguelli, Giuseppe [Department of Applied Biology, University of Perugia, Perugia (Italy); Wopfner, Nicole; Ferreira, Fatima [Department of Molecular Biology, CD Laboratory for Allergy Diagnosis and Therapy, University of Salzburg, Salzburg (Austria); D' Amato, Gennaro [Division of Respiratory and Allergic Diseases, ' A. Cardarelli' High Speciality Hospital, Naples (Italy); Ederli, Luisa [Department of Applied Biology, University of Perugia, Perugia (Italy)

    2011-10-15

    Air pollution is frequently proposed as a cause of the increased incidence of allergy in industrialised countries. We investigated the impact of ozone (O{sub 3}) on reactive oxygen species (ROS) and allergen content of ragweed pollen (Ambrosia artemisiifolia). Pollen was exposed to acute O{sub 3} fumigation, with analysis of pollen viability, ROS and nitric oxide (NO) content, activity of nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase, and expression of major allergens. There was decreased pollen viability after O{sub 3} fumigation, which indicates damage to the pollen membrane system, although the ROS and NO contents were not changed or were only slightly induced, respectively. Ozone exposure induced a significant enhancement of the ROS-generating enzyme NAD(P)H oxidase. The expression of the allergen Amb a 1 was not affected by O{sub 3}, determined from the mRNA levels of the major allergens. We conclude that O{sub 3} can increase ragweed pollen allergenicity through stimulation of ROS-generating NAD(P)H oxidase. - Highlights: > O{sub 3} reduces the viability of ragweed pollen. > ROS and allergens of ragweed pollen were not affected by O{sub 3} exposure. > O{sub 3} enhances the activity of the ROS-generating enzyme NAD(P)H oxidase. > O{sub 3} increases ragweed pollen allergenicity through NAD(P)H-oxidase stimulation. - This study focuses on the effects of the atmospheric pollutant ozone on ROS content and NAD(P)H oxidase activity of ragweed pollen grains.

  9. Direct electron transfer and biosensing of glucose oxidase immobilized at multiwalled carbon nanotube-alumina-coated silica modified electrode

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Wei-Che; Huang, Jian-Lung; Tsai, Yu-Chen, E-mail: yctsai@dragon.nchu.edu.tw

    2012-05-01

    Investigations are reported regarding the direct electrochemical performance of glucose oxidase (GOD) immobilized on a film of multiwalled carbon nanotube-alumina-coated silica (MWCNT-ACS). The surface morphology of the GOD/MWCNT-ACS nanobiocomposite is characterized by scanning electron microscopy. In cyclic voltammetric response, the immobilized GOD displays a pair of well-defined redox peaks, with a formal potential (E Degree-Sign Prime ) of - 0.466 V versus Ag/AgCl in a 0.1 M phosphate buffer solution (pH 7.5) at a scan rate of 0.05 V s{sup -1}; also the electrochemical response indicates a surface-controlled electrode process. The dependence of formal potential on solution pH indicates that the direct electron transfer reaction of GOD is a reversible two-electron coupled with a two-proton electrochemical reaction process. The glucose biosensor based on the GOD/MWCNT-ACS nanobiocomposite shows a sensitivity of 0.127 A M{sup -1} cm{sup -2} and an apparent Michaelis-Menten constant of 0.5 mM. Furthermore, the prepared biosensor exhibits excellent anti-interference ability to the commonly co-existed uric acid and ascorbic acid. - Highlights: Black-Right-Pointing-Pointer A film composed of MWCNT-ACS was used for biosensor application. Black-Right-Pointing-Pointer High sensitivity and good selectivity were obtained for the detection of glucose. Black-Right-Pointing-Pointer This approach is potential for fabrication of mediator-free biosensor.

  10. Electrochemically Functionalized Seamless Three-Dimensional Graphene-Carbon Nanotube Hybrid for Direct Electron Transfer of Glucose Oxidase and Bioelectrocatalysis.

    Science.gov (United States)

    Terse-Thakoor, Trupti; Komori, Kikuo; Ramnani, Pankaj; Lee, Ilkeun; Mulchandani, Ashok

    2015-12-01

    Three-dimensional seamless chemical vapor deposition (CVD) grown graphene-carbon nanotubes (G-CNT) hybrid film has been studied for its potential in achieving direct electron transfer (DET) of glucose oxidase (GOx) and its bioelectrocatalytic activity in glucose detection. A two-step CVD method was employed for the synthesis of seamless G-CNT hybrid film where CNTs are grown on already grown graphene film on copper foil using iron as a catalyst. Physical characterization using SEM and TEM show uniform dense coverage of multiwall carbon nanotubes (MWCNT) grown directly on graphene with seamless contacts. The G-CNT hybrid film was electrochemically modified to introduce oxygenated functional groups for DET favorable immobilization of GOx. Pristine and electrochemically functionalized G-CNT film was characterized by electrochemical impedance spectroscopy (EIS), cyclic voltammetry, X-ray photoelectron-spectroscopy, and Raman spectroscopy. The DET between GOx and electrochemically oxidized G-CNT electrode was studied using cyclic voltammetry which showed a pair of well-defined and quasi-reversible redox peaks with a formal potential of -459 mV at pH 7 corresponding to the redox site of GOx. The constructed electrode detected glucose concentration over the clinically relevant range of 2-8 mM with the highest sensitivity of 19.31 μA/mM/cm(2) compared to reported composite hybrid electrodes of graphene oxide and CNTs. Electrochemically functionalized CVD grown seamless G-CNT structure used in this work has potential to be used for development of artificial mediatorless redox enzyme based biosensors and biofuel cells.

  11. Direct electron transfer-based bioanodes for ethanol biofuel cells using PQQ-dependent alcohol and aldehyde dehydrogenases

    International Nuclear Information System (INIS)

    Aquino Neto, Sidney; Suda, Emily L.; Xu, Shuai; Meredith, Matthew T.; De Andrade, Adalgisa R.; Minteer, Shelley D.

    2013-01-01

    This paper compares the performance of a DET (direct electron transfer) bioanode containing both PQQ-ADH (pyrroloquinoline quinone-dependent alcohol dehydrogenase) and PQQ-AldDH (PQQ-dependent aldehyde dehydrogenase) immobilized onto different modified electrode surfaces employing either a tetrabutylammonium (TBAB)-modified Nafion ® membrane polymer or polyamidoamine (PAMAM) dendrimers for the enzyme immobilization. The electrochemical characterization showed that the prepared bioelectrodes were able to undergo DET onto glassy carbon surface in the presence as well as the absence of multi-walled carbon nanotubes (MWCNTs); also, in the latter case a relevant shift in the oxidation peak of about 180 mV vs. saturated calomel electrode (SCE) was observed. A very similar redox potential was achieved with the self-assembled bioelectrode prepared onto modified-gold surfaces with dendrimers, indicating that both methodologies provide an environment that enables the PQQ-enzymes to undergo DET. The biofuel cell tests confirmed the ease of the DET process and the enhanced performance in the presence of the carbon nanotubes. Considering the bioanodes prepared with PAMAM dendrimers, the power density values vary from 19.4 μW cm −2 without MWCNTs to 25.7 μW cm −2 in the presence of MWCNTs. Similarly, with the bioanodes prepared with the TBAB-modified-Nafion ® polymer, the results indicate power densities of 27.9 and 38.4 μW cm −2 respectively. These electrode modifications represent effective methods for immobilization and direct electrical connection of quinohemoproteins to electrode surfaces.

  12. Gold-Coated M13 Bacteriophage as a Template for Glucose Oxidase Biofuel Cells with Direct Electron Transfer.

    Science.gov (United States)

    Blaik, Rita A; Lan, Esther; Huang, Yu; Dunn, Bruce

    2016-01-26

    Glucose oxidase-based biofuel cells are a promising source of alternative energy for small device applications, but still face the challenge of achieving robust electrical contact between the redox enzymes and the current collector. This paper reports on the design of an electrode consisting of glucose oxidase covalently attached to gold nanoparticles that are assembled onto a genetically engineered M13 bacteriophage using EDC-NHS chemistry. The engineered phage is modified at the pIII protein to attach onto a gold substrate and serves as a high-surface-area template. The resulting "nanomesh" architecture exhibits direct electron transfer (DET) and achieves a higher peak current per unit area of 1.2 mA/cm(2) compared to most other DET attachment schemes. The final enzyme surface coverage on the electrode was calculated to be approximately 4.74 × 10(-8) mol/cm(2), which is a significant improvement over most current glucose oxidase (GOx) DET attachment methods.

  13. Direct measurements of wind-water momentum coupling in a marsh with emergent vegetation and implications for gas transfer estimates

    Science.gov (United States)

    Tse, I.; Poindexter, C.; Variano, E. A.

    2013-12-01

    Among the numerous ecological benefits of restoring wetlands is carbon sequestration. As emergent vegetation thrive, atmospheric CO2 is removed and converted into biomass that gradually become additional soil. Forecasts and management for these systems rely on accurate knowledge of gas exchange between the atmosphere and the wetland surface waters. Our previous work showed that the rate of gas transfer across the air-water interface is affected by the amount of water column mixing caused by winds penetrating through the plant canopy. Here, we present the first direct measurements of wind-water momentum coupling made within a tule marsh. This work in Twitchell Island in the California Delta shows how momentum is imparted into the water from wind stress and that this wind stress interacts with the surface waters in an interesting way. By correlating three-component velocity signals from a sonic anemometer placed within the plant canopy with data from a novel Volumetric Particle Imager (VoPI) placed in the water, we measure the flux of kinetic energy through the plant canopy and the time-scale of the response. We also use this unique dataset to estimate the air-water drag coefficient using an adjoint method.

  14. An experimental observation of the effect of flow direction for evaporation heat transfer in plate heat exchanger

    International Nuclear Information System (INIS)

    Lin, Yueh-Hung; Li, Guang-Cheng; Yang, Chien-Yuh

    2015-01-01

    This study provides an Infrared Thermal Image observation on the evaporation heat transfer of refrigerant R-410A in plate heat exchanger with various flow arrangement and exit superheat conditions. An experimental method was derived for estimating the superheat region area of two-phase refrigerant evaporation in plate heat exchanger. The experimental results show that the superheat region area for parallel flow is much larger than that for counter flow as that estimated by Yang et al. [9]. There is an early superheated region at the central part of the plate heat exchanger for parallel flow arrangement. This effect is not significant for counter flow arrangement. The Yang et al. [9] method under estimated the superheat area approximately 40%–53% at various flow rates and degree of exit superheat. Even though the flow inside a plate heat exchanger is extremely turbulent because of the chevron flow passages, the assumption of uniform temperature distribution in the cross section normal to the bulk flow direction will cause significant uncertainties for estimating the superheat area for refrigerant evaporating in a plate heat exchanger

  15. Propidium iodide competes with Ca(2+) to label pectin in pollen tubes and Arabidopsis root hairs.

    Science.gov (United States)

    Rounds, Caleb M; Lubeck, Eric; Hepler, Peter K; Winship, Lawrence J

    2011-09-01

    We have used propidium iodide (PI) to investigate the dynamic properties of the primary cell wall at the apex of Arabidopsis (Arabidopsis thaliana) root hairs and pollen tubes and in lily (Lilium formosanum) pollen tubes. Our results show that in root hairs, as in pollen tubes, oscillatory peaks in PI fluorescence precede growth rate oscillations. Pectin forms the primary component of the cell wall at the tip of both root hairs and pollen tubes. Given the electronic structure of PI, we investigated whether PI binds to pectins in a manner analogous to Ca(2+) binding. We first show that Ca(2+) is able to abrogate PI growth inhibition in a dose-dependent manner. PI fluorescence itself also relies directly on the amount of Ca(2+) in the growth solution. Exogenous pectin methyl esterase treatment of pollen tubes, which demethoxylates pectins, freeing more Ca(2+)-binding sites, leads to a dramatic increase in PI fluorescence. Treatment with pectinase leads to a corresponding decrease in fluorescence. These results are consistent with the hypothesis that PI binds to demethoxylated pectins. Unlike other pectin stains, PI at low yet useful concentration is vital and specifically does not alter the tip-focused Ca(2+) gradient or growth oscillations. These data suggest that pectin secretion at the apex of tip-growing plant cells plays a critical role in regulating growth, and PI represents an excellent tool for examining the role of pectin and of Ca(2+) in tip growth.

  16. Pollen analysis in honey samples from the two main producing regions in the Brazilian northeast.

    Science.gov (United States)

    Sodré, Geni da S; Marchini, Luís C; Carvalho, Carlos A L de; Moreti, Augusta C de C C

    2007-09-01

    Knowledge about the botanical source of honey is very important for the beekeeper while it indicates adequate and abundant supply sources of nectar and pollen for the bees, thus contributing toward improved yield. The present study means to identify the pollen types occurring in 58 samples of honey produced in two states of the northeastern region of Brazil, Piauí (38 samples) and Ceará (20 samples), and to verify the potential of the honey plants during the months of February to August. The samples were obtained directly from beekeepers in each state and analyzed at the Apiculture Laboratory of the Entomology Section of Escola Superior de Agricultura "Luiz de Queiroz", USP, Piracicaba, State of São Paulo, Brazil. The pollen analysis was performed using the acetolysis method. The samples were submitted to both a qualitative and a quantitative analysis. The dominant pollen in the State of Ceará is from Mimosa caesalpiniaefolia, M. verrucosa, Borreria verticillata, Serjania sp., and a Fabaceae pollen type, while in the State of Piauí it is from Piptadenia sp., M. caesalpiniaefolia, M. verrucosa, Croton urucurana and Tibouchina sp.

  17. Distribution of pectins in the pollen apertures of Oenothera hookeri.velans ster/+ster.

    Science.gov (United States)

    Noher de Halac, I; Cismondi, I A; Rodriguez-Garcia, M I; Famá, G

    2003-04-01

    Cell wall pectins are some of the most complex biopolymers known, and yet their functions remain largely mysterious. The aim of this paper was to deepen the study of the spatial pattern of pectin distribution in the aperture of Oenothera hookeri.velans ster/+ster fertile pollen. We used "in situ" immunocytochemical techniques at electron microscopy, involving monoclonal antibodies JIM5 and JIM7 directed against pectin epitopes in fertile pollen grains of Oenothera hookeri.velans ster/+ster. The same region was also analyzed by classical cytochemistry for polysaccharide detection. Immunogold labelling at the JIM7 epitope showed only in mature pollen labelling mainly located at the intine endo-aperture region. Cytoplasmic structures near the plasma membrane of the vegetative cell showed no labelling gold grains. In the same pollen stge the labelling at the JIM5 epitope was mostly confined to a layer located in the limit between the endexine and the ektexine at the level of the border of the oncus. Some tubuli at the base of the ektexine showed also an accumulation of gold particles. No JIM5 label was demonstrated in the aperture chamber and either in any cytoplasmic structure of the pollen grains. The immunocytochemical technique, when compared with the traditional methods for non-cellulose polysaccharide cytochemistry is fare more sensitive and allows the univocal determination of temporal and spatial location of pectins recognized by the JIM7 and JIM5 MAbs.

  18. Pollen, water, and wind: Chaotic mixing in a puddle of water

    DEFF Research Database (Denmark)

    Jensen, Kaare Hartvig

    2016-01-01

    and nutrient distribution in puddles and small ponds.The flow patterns are generated by wind blowing across the puddle surface. This causes a shear stress at the atmospheric interface, which drives a flow in the liquid below. Chaotic mixing can occur if the wind direction changes over time. A fluid patch......This paper talks about how pine pollen grains dispersedin an approximately 1 m wide and 1 cm deep water puddle. The pollen has mixed due to wind blowing across the liquid surface, revealing a strikingly complex flow pattern. The flows revealed by nature’s tracer particles may influence circulation...

  19. Pollen and spore monitoring in the world.

    Science.gov (United States)

    Buters, J T M; Antunes, C; Galveias, A; Bergmann, K C; Thibaudon, M; Galán, C; Schmidt-Weber, C; Oteros, J

    2018-01-01

    Ambient air quality monitoring is a governmental duty that is widely carried out in order to detect non-biological ("chemical") components in ambient air, such as particles of monitoring networks are publicly funded and air quality data are open to the public. The situation for biological particles that have detrimental effects on health, as is the case of pollen and fungal spores, is however very different. Most pollen and spore monitoring networks are not publicly funded and data are not freely available. The information regarding which biological particle is being monitored, where and by whom, is consequently often not known, even by aerobiologists themselves. This is a considerable problem, as local pollen data are an important tool for the prevention of allergic symptoms. The aim of this study was to review pollen monitoring stations throughout the world and to create an interactive visualization of their distribution. The method employed to collect information was based on: (a) a review of the recent and historical bibliography related to pollen and fungal spore monitoring, and (b) personal surveys of the managers of national and regional monitoring networks. The interactive application was developed using the R programming language. We have created an inventory of the active pollen and spore monitoring stations in the world. There are at least 879 active pollen monitoring stations in the world, most of which are in Europe (> 500). The prevalent monitoring method is based on the Hirst principle (> 600 stations). The inventory is visualised as an interactive and on-line map. It can be searched, its appearance can be adjusted to the users' needs and it is updated regularly, as new stations or changes to those that already exist can be submitted online. The map shows the current situation of pollen and spore monitoring and facilitates collaboration among those individuals who are interested in pollen and spore counts. It might also help to improve the

  20. Pollen Characterization in Size Segregated Atmospheric Aerosol

    Science.gov (United States)

    Kolpakova, Anna; Hovorka, Jan; Klán, Miroslav

    2017-12-01

    The first stage of a High Volumetric Cascade Impactor - HiVol (BGI-900), used for sampling of aerosol particles larger than 10 micrometres in aerodynamic diameter, was tested for bioaerosol sampling. Low air flow-rate and low pressure-drop at the jets of the first stage and high air volume are advantageous parameters, which would favour the use of the first stage for bioaerosol sampling. The sampling went in urban, rural and background localities, Prague, Brezno and Laz respectively in the Czech Republic, in summer and autumn. Pollen was separated from the impaction substrate, polyurethane foam, into homogeneous deposit on Nylon filter. The homogeneity of the deposit varied within 4%. Representative portion of the deposit was analysed by a scanning electron microscopy - SEM. There were taken 485 SEM images from 12 samples in 3 localities. Pollen grains were identified in 295 SEM images and determined into 9 genus and 4 families. Median pollen grain concentrations/deformities were 9m-3/24%, 3m-3/18%, 8m-3/50% for Prague, Brezno and Láz localities respectively. The pollen grains of the Poaceae family were found with the highest frequency in all localities. Number of pollen increased with total aerosol mass in Prague locality only. There were also identified brochosomes, rather unique insect secretion products, in the samples from the Láz locality.

  1. Bee food: the chemistry and nutritional value of nectar, pollen and ...

    African Journals Online (AJOL)

    Bees are herbivorous insects, consuming nectar and pollen throughout their life cycles. This paper is a brief review of the chemistry of these two floral resources and the implications for bee nutrition. Nectar is primarily an energy source, but in addition to sugars contains various minor constituents that may, directly or ...

  2. Occupational Allergy to Peach (Prunus persica) Tree Pollen and Potential Cross-Reactivity between Rosaceae Family Pollens.

    Science.gov (United States)

    Jiang, Nannan; Yin, Jia; Mak, Philip; Wen, Liping

    2015-10-01

    Orchard workers in north China are highly exposed to orchard pollens, especially peach and other Rosaceae family pollens during pollination season. The aim of this study was to investigate whether occupational allergy to peach tree pollen as a member of Rosaceae family is IgE-mediated and to evaluate the cross-reactivity among Rosaceae family pollens. Allergen skin test and conjunctival challenge test were performed; enzyme linked immune-sorbent assay (ELISA), inhibiting ELISA, western immunoblotting and inhibiting western immunoblotting were done with Rosaceae family orchard pollens, including peach, apricot, cherry, apple and pear tree pollens. Mass spectrometry was also performed to probe the main allergen component and cross-reactive protein. Sensitizations to peach pollen were found in both skin test and conjunctival challenge in the patients. Serum specific IgE to three pollens (peach, apricot and cherry) were detected through ELISA. When peach pollen used as solid phase, ELISA inhibition revealed other four kinds of pollens capable of inducing partial to strong inhibitions (45% to 87%), with the strongest inhibition belonging to apricot pollen (87%). Western blotting showed predominant IgE binding to a 20 KD protein among these pollens, which appeared to be a cross-reactive allergen component through western blotting inhibition. It was recognized as a protein homologous to glutathione s-transferase 16 from Arabidopsis thaliana. Peach and other Rosaceae family tree pollen may serve as a potential cause of IgE mediated occupational respiratory disease in orchard workers in north China.

  3. Influence of gamma irradiation on pollen viability, germination ability ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-12-15

    Dec 15, 2009 ... minor cross-incompatibilities and physiological studies of incompatibility ... campanula shape of the flowers attractive for insect. (bees are ..... irradiation of cacao (Theobroma cacao L.) pollen: Effect on pollen grain viability ...

  4. Pollen parameters estimates of genetic variability among newly ...

    African Journals Online (AJOL)

    Pollen parameters estimates of genetic variability among newly selected Nigerian roselle (Hibiscus sabdariffa L.) genotypes. ... Estimates of some pollen parameters where used to assess the genetic diversity among ... HOW TO USE AJOL.

  5. Effects of palm pollen on folliculogenesis process after treatment ...

    African Journals Online (AJOL)

    Effects of palm pollen on folliculogenesis process after treatment with cyclophosphamide among rats. ... Background and purpose: Palm pollen is a good source of natural antioxidants and has a high level of health ... HOW TO USE AJOL.

  6. In vitro pollen quantity, viability and germination tests in quince

    African Journals Online (AJOL)

    use

    2011-11-21

    Nov 21, 2011 ... rootstock pollens were collected in April from the unopened pink balloon-stage flowers on mature trees ..... their pollen characteristics to be used in cross breeding ... viability and germination levels for pistachio and terebinth in.

  7. Pollen morphology and variability of Tulipa hungarica Borb

    African Journals Online (AJOL)

    Yomi

    2012-01-10

    Jan 10, 2012 ... Pollen morphology of the endemic species Tulipa hungarica Borb was investigated with the goal of ... pollen size may balance the competitive advantages of .... (2009). Comparative analysis of microspore size variability in the.

  8. Effect of readout direction in the edge profile on the modulation transfer function of computed radiographic systems by use of the edge method.

    Science.gov (United States)

    Tanaka, Nobukazu; Morishita, Junji; Tsuda, Norisato; Ohki, Masafumi

    2013-07-01

    We investigated the effect of the readout direction of the edge profile obtained by the edge method on the presampled modulation transfer function (MTF) in various computed radiographic (CR) systems. There were no differences in the MTFs derived from two edge profiles in the sub-scanning direction of four CR systems used in this study. On the other hand, the MTFs measured at a readout direction from the low (edge) to the high (direct exposure) exposure region were higher than those measured at a readout direction from the high to the low exposure region in the laser-beam scanning direction for three of the four CR systems. Although this phenomenon depends on the CR system, it is important to understand and indicate both MTFs at the two edge profiles in the laser-beam scanning direction for accurate assessment of the resolution property.

  9. Differential skin test reactivity to pollens in pollen food allergy syndrome versus allergic rhinitis.

    Science.gov (United States)

    Ta, Von; Scott, David R; Chin, William K; Wineinger, Nathan E; Kelso, John M; White, Andrew A

    2015-01-01

    Pollen food allergy syndrome (PFAS), also called oral allergy syndrome, is a form of food allergy in which uncooked foods cause allergic symptoms generally limited to the oral mucosa. It occurs in a subset of patients with pollen allergy, although not all patients have prominent rhinitis symptoms. PFAS is related to antigenic similarity between the pollen and food allergen. The size of skin test reactions in a group of subjects with pollen sensitivity with PFAS was compared with a group of subjects who were pollen sensitive and without PFAS. Self-reported rhinitis symptoms between the two groups were compared to identify if symptom severity differed. Twenty subjects with PFAS and 20 subjects with seasonal allergic rhinitis without PFAS were enrolled in the study. All the subjects underwent standard skin-prick testing to a panel of common allergens, including select fresh fruits and vegetables. The subjects completed a Mini Rhinoconjunctivitis Quality of Life Questionnaire as part of their clinical evaluation. The subjects with PFAS and those without PFAS were compared statistically. The subjects with PFAS had significantly larger-sized skin-prick test results specific to pollens (p PFAS reported milder nasal symptoms in relation to pollen skin test result size when compared with allergic rhinitis controls without PFAS. Our study outlined basic differences between two seemingly similar patient groups with a particularly striking discordance between skin test result sizes and rhinitis symptoms. This discordance should be explored further to increase mechanistic understanding of allergen cross-reactivity in PFAS.

  10. Effect of pollen load size and source (self, outcross) on seed and fruit production in highbush blueberry cv. 'Bluecrop' (VACCINIUM CORYMBOSUM; Ericaceae).

    Science.gov (United States)

    Dogterom, M H; Winston, M L; Mukai, A

    2000-11-01

    pollen load size and source requirements of a crop plant and the limits to pollen transfer when translated to fruit growth.

  11. The revised edition of korean calendar for allergenic pollens.

    Science.gov (United States)

    Oh, Jae-Won; Lee, Ha-Baik; Kang, Im-Joo; Kim, Seong-Won; Park, Kang-Seo; Kook, Myung-Hee; Kim, Bong-Seong; Baek, Hey-Sung; Kim, Joo-Hwa; Kim, Ja-Kyung; Lee, Dong-Jin; Kim, Kyu-Rang; Choi, Young-Jin

    2012-01-01

    The old calendar of pollens did not reflect current pollen distribution and concentrations that can be influenced by changes of weather and environment of each region in South Korea. A new pollen calendar of allergenic pollens was made based on the data on pollen concentrations obtained in eight regions nationwide between 1997 and 2009. The distribution of pollen was assessed every day at 8 areas (Seoul, Guri, Busan, Daegu, Jeonju, Kwangju, Kangneung, and Jeju) for 12 years between July 1, 1997 and June 30, 2009. Pollens were collected by using Burkard 7-day sampler (Burkard Manufacturing Co Ltd, UK). Pollens which were stained with Calberla's fuchsin staining solution were identified and counted. Pine became the highest pollen in May, and the pollen concentrations of oak and birch also became high. Ragweed appeared in the middle of August and showed the highest pollen concentration in the middles of September. Japanese hop showed a high concentration between the middle of August and the end of September, and mugwort appeared in the middles of August and its concentration increased up until early September. In Kangneung, birch appeared earlier, pine showed a higher pollen concentration than in the other areas. In Daegu, Oriental thuja and alder produced a large concentration of pollens. Pine produced a large concentration of pollens between the middle of April and the end of May. Weeds showed higher concentrations in September and mugwort appeared earlier than ragweed. In Busan the time of flowering is relatively early, and alder and Oriental thuja appeared earliest among all areas. In Kwangju, Oriental thuja and hazelnut appeared in early February. Japanese cedar showed the highest pollen concentration in March in Jeju. In conclusion, update information on pollen calendar in South Korea should be provided for allergic patients through the website to manage and prevent the pollinosis.

  12. Pollen spectrum of propolis samples from São Paulo State, Brazil - doi: 10.4025/actascianimsci.v35i3.18389

    Directory of Open Access Journals (Sweden)

    Ricardo Oliveira Orsi

    2013-07-01

    Full Text Available The pollen spectrum of propolis is a good indicative of the phytogeographical origin of the bee product and the local flora available for bee visiting. The present study aimed to perform pollen analysis of propolis produced by Apis mellifera L., in the São Paulo State, Brazil. Propolis samples were directly obtained from beekeepers and slides were prepared for qualitative and quantitative analysis of pollen after propolis extraction. According to the results twenty-eight types of pollen were found and distributed in fifteen botanical families. Pollens from Mimosoideae and Myrtaceae types were found in all samples. In São Paulo State, there is a wide variety of vegetal sources which are components of the final propolis composition.   

  13. The clinical relevance of sensitization to pollen-related fruits and vegetables in unselected pollen-sensitized adults

    DEFF Research Database (Denmark)

    Osterballe, M.; Hansen, T.K.; Mørtz, Charlotte G

    2005-01-01

    BACKGROUND: Previous studies have described cross-reactivity between fresh fruits, vegetables and pollen. However, no data demonstrates the clinical relevance of sensitization to pollen-related fruits and vegetables in unselected pollen-sensitized adults with and without symptoms in the pollen...... season. OBJECTIVE: The aim of this study was to estimate the clinical relevance of sensitization to pollen-related fruits and vegetables in unselected pollen-sensitized adults and to examine the diagnostic value of skin-prick test (SPT), histamine release and specific IgE compared with the outcome...... of oral challenge. METHODS: In total, 936 unselected adults (female : male 479 : 457, median age 33.7 years) were examined for pollen sensitization and clinical cross-reactivity with pollen-related fruits and vegetables by questionnaire, SPT, histamine release, specific IgE and oral challenge. RESULTS...

  14. Pollen Dispersion Forecast At Regional Scale

    Science.gov (United States)

    Mangin, A.; Asthma Forecast System Team

    The forecast of the pollen concentration is generally based on an identification of sim- ilar coincidence of measured pollen at given points and meteorological data that is searched in an archive and which, with the help of experts, allows building a predicted value. This may be classified under the family of statistical approaches for forecast- ing. While palynologists make these methods more and more accurate with the help of innovative techniques of regression against empirical rules and/or evolving mathe- matical structures (e.g. neural networks), the spatial dispersion of the pollen is not or poorly considered, mainly because it requires a lot of means and technique that are not familiar to this scientific discipline. The research on pollen forecasts are presently mainly focused on the problematic of modeling the behavior of pollen trends and sea- sons at one location regardless of the topography, the locations of emitters, the relative strengths of emitter, in one word the Sspatial backgroundT. This research work was a & cedil;successful attempt to go a step further combining this SlocalT approach with a trans- & cedil;port/dispersion modeling allowing the access to mapping of concentration. The areas of interest that were selected for the demonstration of feasibility were 200x200km zones centered on Cordoba, Barcelona and Bologna and four pollen types were ex- amined, namely: Cupressaceae, Olea europaea, Poaceae and Parietaria. At the end of this three-year European project in December 2001, the system was fully deployed and validated. The multidisciplinary team will present the original methodologies that were derived for modeling the numerous aspects of this problem and also some con- clusions regarding potential extent to other areas and taxa.

  15. Saccharomyces cerevisiae Fermentation Effects on Pollen: Archaeological Implications

    Directory of Open Access Journals (Sweden)

    Crystal A. Dozier

    2016-03-01

    Full Text Available Pollen is the reproductive agent of flowering plants; palynology is utilized by archaeologists because sporopollenin, a major component in the exine of pollen grains, is resistant to decay and morphologically distinctive. Wine, beer, and mead have been identified in the archaeological record by palynological assessment due to indicator species or due to a pollen profile similar to that recovered from honey, a common source of sugar in a variety of fermented beverages. While most palynologists have assumed that pollen grains are resistant to alcoholic fermentation, a recent study in food science implies that pollen is a yeast nutrient because pollen-enriched meads produce more alcohol. The experiment presented here explores the potential distortion of the pollen record through fermentation by brewing a traditional, pollen-rich mead with Saccharomyces cerevisiae. In this experiment, the pollen grains did not undergo any discernible morphological changes nor were distorted in the pollen profile. Any nutrition that the yeast garners from the pollen therefore leaves sporopollenin intact. These results support palynological research on residues of alcoholic beverages and confirms that the fermentation process does not distort the pollen profile of the original substance. The paper concludes with the potential and limits of palynological study to assess fermentation within the archaeological record.

  16. Pollen Biology of Ornamental Ginger (Hedychium spp. J. Koenig)

    Science.gov (United States)

    An improved in vitro pollen germination assay was developed to assess the viability of stored Hedychium pollen. The effect of polyethylene glycol (PEG) (10, 15, and 20% w/v) on pollen germination and tube growth was evaluated for H. longicornutum and two commercial Hedychium cultivars, ‘Orange Brush...

  17. Characteristics of cytomixis in the pollen mother cells of green manure crop Sesbania cannabina

    OpenAIRE

    Kumar, Girjesh; Srivastava, Nitisha

    2013-01-01

    Cytomixis has been reported in many plant species, but there is no published report in Sesbania cannabina spp. The cytological stability of any plant is an important consideration in view of its extensive use in genetics and plant breeding programmes. Present study reveals the occurrence of inter PMC (pollen mother cell) transfer of chromatin material. During present investigation, it was found that out of different doses of gamma rays + ethylmethane sulfonate, the highest dose displayed the ...

  18. DET/MPS - THE GSFC ENERGY BALANCE PROGRAM, DIRECT ENERGY TRANSFER/MULTIMISSION SPACECRAFT MODULAR POWER SYSTEM (UNIX VERSION)

    Science.gov (United States)

    Jagielski, J. M.

    1994-01-01

    The DET/MPS programs model and simulate the Direct Energy Transfer and Multimission Spacecraft Modular Power System in order to aid both in design and in analysis of orbital energy balance. Typically, the DET power system has the solar array directly to the spacecraft bus, and the central building block of MPS is the Standard Power Regulator Unit. DET/MPS allows a minute-by-minute simulation of the power system's performance as it responds to various orbital parameters, focusing its output on solar array output and battery characteristics. While this package is limited in terms of orbital mechanics, it is sufficient to calculate eclipse and solar array data for circular or non-circular orbits. DET/MPS can be adjusted to run one or sequential orbits up to about one week, simulated time. These programs have been used on a variety of Goddard Space Flight Center spacecraft projects. DET/MPS is written in FORTRAN 77 with some VAX-type extensions. Any FORTRAN 77 compiler that includes VAX extensions should be able to compile and run the program with little or no modifications. The compiler must at least support free-form (or tab-delineated) source format and 'do do-while end-do' control structures. DET/MPS is available for three platforms: GSC-13374, for DEC VAX series computers running VMS, is available in DEC VAX Backup format on a 9-track 1600 BPI tape (standard distribution) or TK50 tape cartridge; GSC-13443, for UNIX-based computers, is available on a .25 inch streaming magnetic tape cartridge in UNIX tar format; and GSC-13444, for Macintosh computers running AU/X with either the NKR FORTRAN or AbSoft MacFORTRAN II compilers, is available on a 3.5 inch 800K Macintosh format diskette. Source code and test data are supplied. The UNIX version of DET requires 90K of main memory for execution. DET/MPS was developed in 1990. A/UX and Macintosh are registered trademarks of Apple Computer, Inc. VMS, DEC VAX and TK50 are trademarks of Digital Equipment Corporation. UNIX is a

  19. Characteristics of cytomixis in the pollen mother cells of green manure crop Sesbania cannabina

    Directory of Open Access Journals (Sweden)

    Girjesh Kumar

    2013-09-01

    Full Text Available Cytomixis has been reported in many plant species, but there is no published report in Sesbania cannabina spp. The cytological stability of any plant is an important consideration in view of its extensive use in genetics and plant breeding programmes. Present study reveals the occurrence of inter PMC (pollen mother cell transfer of chromatin material. During present investigation, it was found that out of different doses of gamma rays + ethylmethane sulfonate, the highest dose displayed the highest instances of cytomixis. In present investigation, the phenomenon of cytomixis can be observed between 2 to 10 PMCs. During male meiosis, it occurs through narrow and broad cytoplasmic channels or through direct contact between PMCs from early prophase to late telophase stage. However, the frequency of its occurrence during late meiotic stages is rather low. It elucidates that in Sesbania cannabina, induced cytomixis results into possible sources for production of aneuploids and polyploids. This may be further useful in plant breeding programmes to improve genotypic and phenotypic characters of Sesbania cannabina.

  20. Pollen lipidomics: lipid profiling exposes a notable diversity in 22 allergenic pollen and potential biomarkers of the allergic immune response.

    Directory of Open Access Journals (Sweden)

    Mohamed Elfatih H Bashir

    Full Text Available BACKGROUND/AIM: Pollen grains are the male gametophytes that deliver sperm cells to female gametophytes during sexual reproduction of higher plants. Pollen is a major source of aeroallergens and environmental antigens. The pollen coat harbors a plethora of lipids that are required for pollen hydration, germination, and penetration of the stigma by pollen tubes. In addition to proteins, pollen displays a wide array of lipids that interact with the human immune system. Prior searches for pollen allergens have focused on the identification of intracellular allergenic proteins, but have largely overlooked much of the extracellular pollen matrix, a region where the majority of lipid molecules reside. Lipid antigens have attracted attention for their potent immunoregulatory effects. By being in close proximity to allergenic proteins on the pollen surface when they interact with host cells, lipids could modify the antigenic properties of proteins. METHODOLOGY/PRINCIPAL FINDINGS: We performed a comparative pollen lipid profiling of 22 commonly allergenic plant species by the use of gas chromatography-mass spectroscopy, followed by detailed data mining and statistical analysis. Three experiments compared pollen lipid profiles. We built a database library of the pollen lipids by matching acquired pollen-lipid mass spectra and retention times with the NIST/EPA/NIH mass-spectral library. We detected, identified, and relatively quantified more than 106 lipid molecular species including fatty acids, n-alkanes, fatty alcohols, and sterols. Pollen-derived lipids stimulation up-regulate cytokines expression of dendritic and natural killer T cells co-culture. CONCLUSIONS/SIGNIFICANCE: Here we report on a lipidomic analysis of pollen lipids that can serve as a database for identifying potential lipid antigens and/or novel candidate molecules involved in allergy. The database provides a resource that facilitates studies on the role of lipids in the

  1. Proteomic Analysis of Pollen and Blossom Honey from Rape Seed Brassica Napus L.

    Directory of Open Access Journals (Sweden)

    Borutinskaitė Veronika

    2017-06-01

    Full Text Available In the study, honey from oilseed rape Brassica napus L., and both hand-collected (winter rape Visby and Cult and bee-collected pollen of oilseed rape were analyzed for their proteome content, in order to see if any plant proteins were present to allow the proteo-typing of the oilseed rape honey. Proteins were fractionated by two-dimensional gel electrophoresis (2DE, stained by Coomassie blue and then analyzed by mass spectrometry. All identified proteins were divided into few groups due to their biological function. In 2DE gels with separated proteins from blossom honey, only bee (Apis mellifera main proteins (Major royal jelly protein 1-5 and Glucosidase were found. So we analyzed all proteins using gel-free based analysis with the SYNAPT G2 high definition mass spectrometry. We identified proteins that were present in both oilseed rape pollen and honey (Bna, Polygalacturonase, Non-specific lipid-transfer protein, GAPDH and others. We believe that these proteins are important for the nutritional value of plant pollen-enriched honey and further research is required on honey and honeybee pollen protein.

  2. A plant plasma membrane Ca2+ pump is required for normal pollen tube growth and fertilization

    DEFF Research Database (Denmark)

    Schiøtt, Morten; Romanowsky, Shawn M; Bækgaard, Lone

    2004-01-01

    Ca(2+) signals are thought to play important roles in plant growth and development, including key aspects of pollen tube growth and fertilization. The dynamics of a Ca(2+) signal are largely controlled by influx (through channels) and efflux (through pumps and antiporters). The Arabidopsis genome...... and a high frequency of aborted fertilization, resulting in a >80% reduction in seed set. These findings identify a plasma membrane Ca(2+) transporter as a key regulator of pollen development and fertilization in flowering plants.......Ca(2+) signals are thought to play important roles in plant growth and development, including key aspects of pollen tube growth and fertilization. The dynamics of a Ca(2+) signal are largely controlled by influx (through channels) and efflux (through pumps and antiporters). The Arabidopsis genome......-inducing) plasmid that is transferred to plant cells] gene disruptions of ACA9 were found to result in partial male sterility. Complementation was observed by using a ACA9-yellow fluorescence protein (YFP) fusion that displayed plasma membrane localization. Mutant aca9 pollen displayed a reduced growth potential...

  3. Inherent optical properties of pollen particles: a case study for the morning glory pollen.

    Science.gov (United States)

    Liu, Chao; Yin, Yan

    2016-01-25

    Biological aerosols, such as bacteria, fungal spores, and pollens, play an important role on various atmospheric processes, whereas their inherent optical property is one of the most uncertainties that limit our ability to assess their effects on weather and climate. A numerical model with core-shell structure, hexagonal grids and barbs is developed to represent one kind of realistic pollen particles, and their inherent optical properties are simulated using a pseudo-spectral time domain method. Both the hexagonal grids and barbs substantially affect the modeled pollen optical properties. Results based on the realistic particle model are compared with two equivalent spherical approximations, and the significant differences indicate the importance of considering pollen geometries for their optical properties.

  4. Liquid-Metal/Water Direct Contact Heat Exchange: Flow Visualization, Flow Stability, and Heat Transfer Using Real-Time X-Ray Imaging

    International Nuclear Information System (INIS)

    Abdulla, Sherif H.; Liu Xin; Anderson, Mark H.; Bonazza, Riccardo; Corradini, Michael L.; Cho, Dae; Page, Richard

    2005-01-01

    Advanced reactor system designs are being considered with liquid-metal cooling connected to a steam power cycle. In addition, current reactor safety systems are considering auxiliary cooling schemes that assure ex-vessel debris coolability utilizing direct water injection into molten material pools to achieve core quenching and eventual coolability. The phenomenon common in both applications is direct contact heat exchange. The current study focuses on detailed measurements of liquid-metal/water direct contact heat exchange that is directly applicable to improvements in effective heat transfer in devices that are being considered for both of these purposes.In this study, a test facility was designed at the University of Wisconsin-Madison to map the operating range of liquid-metal/water direct contact heat exchange. The test section (184-cm height, 45.75-cm width, and 10-cm depth) is a rectangular slice of a larger heat exchange device. This apparatus was used not only to provide measurements of integral thermal performance (i.e., volumetric heat transfer coefficient), but also local heat transfer coefficients in a bubbly flow regime with X-ray imaging based on measured parameters such as bubble formation time, bubble rise velocity, and bubble diameters.To determine these local heat transfer coefficients, a complete methodology of the X-ray radiography for two-phase flow measurement has been developed. With this methodology, a high-energy X-ray imaging system is optimized for our heat exchange experiments. With this real-time, large-area, high-energy X-ray imaging system, the two-phase flow was quantitatively visualized. An efficient image processing strategy was developed by combining several optimal digital image-processing algorithms into a software computational tool written in MATLAB called T-XIP. Time-dependent heat transfer-related variables such as bubble volumes and velocities, were determined. Finally, an error analysis associated with these measurements

  5. Consumption of Bt Maize Pollen Containing Cry1Ie Does Not Negatively Affect Propylea japonica (Thunberg (Coleoptera: Coccinellidae

    Directory of Open Access Journals (Sweden)

    Yonghui Li

    2017-03-01

    Full Text Available Propylea japonica (Thunberg (Coleoptera: Coccinellidae are prevalent predators and pollen feeders in East Asian maize fields. They are therefore indirectly (via prey and directly (via pollen exposed to Cry proteins within Bt-transgenic maize fields. The effects of Cry1Ie-producing transgenic maize pollen on the fitness of P. japonica was assessed using two dietary-exposure experiments in the laboratory. In the first experiment, survival, larval developmental time, adult fresh weight, and fecundity did not differ between ladybirds consuming Bt or non-Bt maize pollen. In the second experiment, none of the tested lethal and sublethal parameters of P. japonica were negatively affected when fed a rapeseed pollen-based diet containing Cry1Ie protein at 200 μg/g dry weight of diet. In contrast, the larval developmental time, adult fresh weight, and fecundity of P. japonica were significantly adversely affected when fed diet containing the positive control compound E-64. In both experiments, the bioactivity of the Cry1Ie protein in the food sources was confirmed by bioassays with a Cry1Ie-sensitive lepidopteran species. These results indicated that P. japonica are not affected by the consumption of Cry1Ie-expressing maize pollen and are not sensitive to the Cry1Ie protein, suggesting that the growing of Bt maize expressing Cry1Ie protein will pose a negligible risk to P. japonica.

  6. Small RNA Sequencing Reveals Differential miRNA Expression in the Early Development of Broccoli (Brassica oleracea var. italica) Pollen.

    Science.gov (United States)

    Li, Hui; Wang, Yu; Wu, Mei; Li, Lihong; Jin, Chuan; Zhang, Qingli; Chen, Chengbin; Song, Wenqin; Wang, Chunguo

    2017-01-01

    Pollen development is an important and complex biological process in the sexual reproduction of flowering plants. Although the cytological characteristics of pollen development are well defined, the regulation of its early stages remains largely unknown. In the present study, miRNAs were explored in the early development of broccoli ( Brassica oleracea var. italica ) pollen. A total of 333 known miRNAs that originated from 235 miRNA families were detected. Fifty-five novel miRNA candidates were identified. Sixty of the 333 known miRNAs and 49 of the 55 predicted novel miRNAs exhibited significantly differential expression profiling in the three distinct developmental stages of broccoli pollen. Among these differentially expressed miRNAs, miRNAs that would be involved in the developmental phase transition from uninucleate microspores to binucleate pollen grains or from binucleate to trinucleate pollen grains were identified. miRNAs that showed significantly enriched expression in a specific early stage of broccoli pollen development were also observed. In addition, 552 targets for 127 known miRNAs and 69 targets for 40 predicted novel miRNAs were bioinformatically identified. Functional annotation and GO (Gene Ontology) analysis indicated that the putative miRNA targets showed significant enrichment in GO terms that were related to plant organ formation and morphogenesis. Some of enriched GO terms were detected for the targets directly involved in plant male reproduction development. These findings provided new insights into the functions of miRNA-mediated regulatory networks in broccoli pollen development.

  7. Pollen morphology of some European Rosaceae

    NARCIS (Netherlands)

    Reitsma, Tj.

    1966-01-01

    In this preliminary investigation attention was paid to pollen morphology of West-European species of the Rosaceae. Some new terms were used like fastigium, endocingulus etc. The terminology of Iversen and Troels-Smith has been followed in addition to improvements by Erdtman. A key is given to the

  8. Airborne pollen trends in the Iberian Peninsula.

    Science.gov (United States)

    Galán, C; Alcázar, P; Oteros, J; García-Mozo, H; Aira, M J; Belmonte, J; Diaz de la Guardia, C; Fernández-González, D; Gutierrez-Bustillo, M; Moreno-Grau, S; Pérez-Badía, R; Rodríguez-Rajo, J; Ruiz-Valenzuela, L; Tormo, R; Trigo, M M; Domínguez-Vilches, E

    2016-04-15

    Airborne pollen monitoring is an effective tool for studying the reproductive phenology of anemophilous plants, an important bioindicator of plant behavior. Recent decades have revealed a trend towards rising airborne pollen concentrations in Europe, attributing these trends to an increase in anthropogenic CO2 emissions and temperature. However, the lack of water availability in southern Europe may prompt a trend towards lower flowering intensity, especially in herbaceous plants. Here we show variations in flowering intensity by analyzing the Annual Pollen Index (API) of 12 anemophilous taxa across 12 locations in the Iberian Peninsula, over the last two decades, and detecting the influence of the North Atlantic Oscillation (NAO). Results revealed differences in the distribution and flowering intensity of anemophilous species. A negative correlation was observed between airborne pollen concentrations and winter averages of the NAO index. This study confirms that changes in rainfall in the Mediterranean region, attributed to climate change, have an important impact on the phenology of plants. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Grass Pollen Pollution from Biofuels Farming

    Czech Academy of Sciences Publication Activity Database

    Ratajová, A.; Tříska, Jan; Vrchotová, Naděžda; Kolář, L.; Kužel, S.

    2013-01-01

    Roč. 26, č. 4 (2013), s. 199-203 ISSN 2151-321X R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67179843 Keywords : grass pollen pollution * biofuels farming * temperate climate * PK-fertilization * N-fertilization * phenolic Subject RIV: EH - Ecology, Behaviour Impact factor: 0.556, year: 2013

  10. Ozone affects pollen viability and NAD(P)H oxidase release from Ambrosia artemisiifolia pollen.

    Science.gov (United States)

    Pasqualini, Stefania; Tedeschini, Emma; Frenguelli, Giuseppe; Wopfner, Nicole; Ferreira, Fatima; D'Amato, Gennaro; Ederli, Luisa

    2011-10-01

    Air pollution is frequently proposed as a cause of the increased incidence of allergy in industrialised countries. We investigated the impact of ozone (O(3)) on reactive oxygen species (ROS) and allergen content of ragweed pollen (Ambrosia artemisiifolia). Pollen was exposed to acute O(3) fumigation, with analysis of pollen viability, ROS and nitric oxide (NO) content, activity of nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase, and expression of major allergens. There was decreased pollen viability after O(3) fumigation, which indicates damage to the pollen membrane system, although the ROS and NO contents were not changed or were only slightly induced, respectively. Ozone exposure induced a significant enhancement of the ROS-generating enzyme NAD(P)H oxidase. The expression of the allergen Amb a 1 was not affected by O(3), determined from the mRNA levels of the major allergens. We conclude that O(3) can increase ragweed pollen allergenicity through stimulation of ROS-generating NAD(P)H oxidase. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Integration of Dust Prediction Systems and Vegetation Phenology to Track Pollen for Asthma Alerts in Public Health

    Science.gov (United States)

    Luvall, Jeffrey C.; Sprigg, W. A.; Huete, A.; Nickovic, S.; Pejanovic, G.; Levetin, E.; Van de water, P.; Myers, O.; Budge, A. M.; Krapfl, H.; hide

    2011-01-01

    greenness, dry-down and pollen release. Ground based observational records of pollen release timing and quantities will be used as verification. Techniques developed using MOD09 surface reflectance products will be directly applicable to the next generation sensors such as VIIRS. The resulting deterministic model for predicting and simulating pollen emission and downwind concentration to study details of phenology and meteorology and their dependencies. This information will be used to support the Centers for Disease Control and Prevention (CDC)'s National Environmental Public Health Tracking Program (EPHT) and the State of New Mexico environmental public health decision support for asthma and allergies alerts

  12. Forensic Pollen Evidence from Clothes by the Tape Adhesive Method

    Directory of Open Access Journals (Sweden)

    Chun-Liang Wu

    2006-06-01

    Full Text Available Collection and identification of pollen is becoming important in forensic applications. Many criminal cases have been reported to link suspects to the crime scene by analysis of pollen. Several methods have been used in the pollen collection and analysis, but they are expensive and tedious. Therefore, it is important to develop a simple method to collect pollen grains from clothes. We tried to recover pollen from clothing surface by using the sticky tapes method. The tape adhesive method has been widely used for sample collection for various purposes, but the efficiency of recovery of invisible pollen from clothes has rarely been reported. Therefore, to test the efficiency of the tape adhesive method in recovering pollen from clothes is important. The first author wore clothes that were made from textile S made by the mixture of cotton 60% and polyester fiber 40% to collect pollen from 26 different areas mostly in the northern part of Taiwan and then used cellophane tape D (Sirchie Finger Print Lab., Inc-No. 131LT4 to recover them from different body parts. Twenty-six pollen taxa were detected in different parts of clothes depending upon what kind of plant the first author stayed near. From the results, we concluded that the tape adhesive method is suitable in recovering pollen from clothes. We have suggested that the tape adhesive method could be part of methods for collecting pollen from clothes of suspects. It is simpler, faster and less expensive than other methods.

  13. Pollen Processing Behavior of Heliconius Butterflies: A Derived Grooming Behavior

    Science.gov (United States)

    Hikl, Anna-Laetitia; Krenn, Harald W.

    2011-01-01

    Pollen feeding behaviors Heliconius and Laparus (Lepidoptera: Nymphalidae) represent a key innovation that has shaped other life history traits of these neotropical butterflies. Although all flower visiting Lepidoptera regularly come in contact with pollen, only Heliconius and Laparus butterflies actively collect pollen with the proboscis and subsequently take up nutrients from the pollen grains. This study focused on the behavior of pollen processing and compared the movement patterns with proboscis grooming behavior in various nymphalid butterflies using video analysis. The proboscis movements of pollen processing behavior consisted of a lengthy series of repeated coiling and uncoiling movements in a loosely coiled proboscis position combined with up and down movements and the release of saliva. The proboscis-grooming behavior was triggered by contamination of the proboscis in both pollen feeding and non-pollen feeding nymphalid butterflies. Proboscis grooming movements included interrupted series of coiling and uncoiling movements, characteristic sideways movements, proboscis lifting, and occasionally full extension of the proboscis. Discharge of saliva was more pronounced in pollen feeding species than in non-pollen feeding butterfly species. We conclude that the pollen processing behavior of Heliconius and Laparus is a modified proboscis grooming behavior that originally served to clean the proboscis after contamination with particles. PMID:22208893

  14. The importance of cross-reactivity in grass pollen allergy

    Directory of Open Access Journals (Sweden)

    Aleksić Ivana

    2014-01-01

    Full Text Available According to the data obtained from in vivo and in vitro testing in Serbia, a significant number of patients have allergic symptoms caused by grass pollen. We examined the protein composition of grass pollens (Dactylis glomerata, Lolium perenne and Phleum pratense and cross-reactivity in patients allergic to grass pollen from our region. The grass pollen allergen extract was characterized by SDS-PAGE, while cross-reactivity of single grass pollens was revealed by immunoblot analysis. A high degree of cross-reactivity was demonstrated for all three single pollens in the sera of allergic patients compared to the grass pollen extract mixture. Confirmation of the existence of cross-reactivity between different antigenic sources facilitates the use of monovalent vaccines, which are easier to standardize and at the same time prevent further sensitization of patients and reduces adverse reactions. [Projekat Ministarstva nauke Republike Srbije, br. 172049 i br. 172024

  15. Ultrastructure of Withania Somnifera (L.) Dunal pollen grains

    International Nuclear Information System (INIS)

    Alwadie, H.M.

    2002-01-01

    Light, scanning and transmission electron microscopy were used to study the morphology and ultrastructure of Withania Somnifera (L.) Dunall pollen grains. Light microscopic examination revealed that the pollen grains are tri- or tetrazonocoplate grains, approximately as long as broad, measuring 29-um. Scanning electron microscopic observation showed that surface sculpturing of the pollen is scarbate-granulate. Ultrathin sections as examined by transmission electron microscope showed that the pollen contained numerous starch grains, lipid droplets, endoplasmic reticulum and vesicles of dictyosomes. Two layers of the pollen wall were also distinguished, the outer wall (exine) divided into ektexine and endexine as well as the inner layer (intine). The nutritive values of Withania pollen are discussed. The importance of studying the ultrastructure of pollen grains as a new tool in palynology is also discussed. (author)

  16. The effect of irradiation on date palm pollen grains

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, M M; Alajaily, F R [The National Academy for Scientific Research Tripoli (Libyan Arab Jamahiriya)

    1995-10-01

    The evaluation of male date palm is very important in date palm culture, it is very well known that the source of pollen has its influence on fruit set, physical and chemical characters of the fruits. Date pollen was collected from previously studied male date palm trees. The pollen was subjected to the following irradiation treatments: 0,5, 10, 20, 40, 80 krad. The irradiated pollen was treated with acetocarmine and its viability was studied under the light microscope. No differences were observed between the treated pollen and the control. The pollen was germinated on agar, sucrose and boric acid media in an incubator at 27 degree C for hours. Germination count under the light microscope indicated that there were no significant differences between 5, 10, 20 krad treatments and the control, but the high doses reduced the germination percentage. The irradiated pollen used to pollinate date palm trees and the effect of metaxynia was studied. 3 tabs.

  17. Aerobiology of Juniperus Pollen in Oklahoma, Texas, and New Mexico

    Science.gov (United States)

    Levetin, Estelle; Bunderson, Landon; VandeWater, Pete; Luvall, Jeff

    2014-01-01

    Pollen from members of the Cupressaceae are major aeroallergens in many parts of the world. In the south central and southwest United States, Juniperus pollen is the most important member of this family with J. ashei (JA) responsible for severe winter allergy symptoms in Texas and Oklahoma. In New Mexico, pollen from J. monosperma (JM) and other Juniperus species are important contributors to spring allergies, while J. pinchotii (JP) pollinates in the fall affecting sensitive individuals in west Texas, southwest Oklahoma and eastern New Mexico. Throughout this region, JA, JM, and JP occur in dense woodland populations. Generally monitoring for airborne allergens is conducted in urban areas, although the source for tree pollen may be forested areas distant from the sampling sites. Improved pollen forecasts require a better understanding of pollen production at the source. The current study was undertaken to examine the aerobiology of several Juniperus species at their source areas for the development of new pollen forecasting initiatives.

  18. Exceptional preservation of Miocene pollen: plasmolysis captured in salt?

    Energy Technology Data Exchange (ETDEWEB)

    Durska, W.

    2016-07-01

    Exceptionally well-preserved Miocene pollen from the Bochnia salt mine of southern Poland is reported herein. The halite deposits within the salt mine belonging to Late Badenian (Miocene) marine evaporites originated in the Paratethys. Rounded and angular structures are present inside pollen grains. On the basis of the similarity with plasmolyzed pollen grains of modern plants, these structures are considered to represent cytoplasms plasmolyzed in the condensed brine prior to fossilization. Two forms of plasmolyzed cytoplasms (concave and convex) can be observed in modern pollen. Both are distinguished in the investigated fossil material. In porate and colporate grains the shape of the plasmolyzed cellular content is concave while in inaperturate it is convex. The plasmolysis form depends on the type of apertures and pollen shape. The percentage of pollen with fossilized cytoplasms within individual taxa is a valuable environmental indicator, as it depends on the proximity of the pollen-producing plant assemblages to the depositional setting. (Author)

  19. Exposure to environmentally-relevant levels of ozone negatively influence pollen and fruit development

    International Nuclear Information System (INIS)

    Gillespie, Colin; Stabler, Daniel; Tallentire, Eva; Goumenaki, Eleni; Barnes, Jeremy

    2015-01-01

    A combination of in vitro and in vivo studies on tomato (Lycopersicon esculentum Mill. cv. Triton) revealed that environmentally-relevant levels of ozone (O_3) pollution adversely affected pollen germination, germ tube growth and pollen-stigma interactions – pollen originating from plants raised in charcoal-Purafil"® filtered air (CFA) exhibited reduced germ tube development on the stigma of plants exposed to environmentally-relevant levels of O_3. The O_3-induced decline in in vivo pollen viability was reflected in increased numbers of non-fertilized and fertilized non-viable ovules in immature fruit. Negative effects of O_3 on fertilization occurred regardless of the timing of exposure, with reductions in ovule viability evident in O_3 × CFA and CFA × O_3 crossed plants. This suggests O_3-induced reductions in fertilization were associated with reduced pollen viability and/or ovule development. Fruit born on trusses independently exposed to 100 nmol mol"−"1 O_3 (10 h d"−"1) from flowering exhibited a decline in seed number and this was reflected in a marked decline in the weight and size of individual fruit – a clear demonstration of the direct consequence of the effects of the pollutant on reproductive processes. Ozone exposure also resulted in shifts in the starch and ascorbic acid (Vitamin C) content of fruit that were consistent with accelerated ripening. The findings of this study draw attention to the need for greater consideration of, and possibly the adoption of weightings for the direct impacts of O_3, and potentially other gaseous pollutants, on reproductive biology during ‘risk assessment’ exercises. - Highlights: • Environmentally-relevant levels of ozone exert negative effects on pollen viability that translate into direct impacts on fruit yield. • Negative impacts of O_3 pollution on reproductive processes were evident regardless of the stage of plant development. • Exposure to environmentally-relevant levels of O_3

  20. Intact goal-directed control in treatment-seeking drug users indexed by outcome-devaluation and Pavlovian to instrumental transfer: Critique of habit theory.

    Science.gov (United States)

    Hogarth, Lee; Lam-Cassettari, Christa; Pacitti, Helena; Currah, Tara; Mahlberg, Justin; Hartley, Lucie; Moustafa, Ahmed

    2018-05-22

    Animal studies have demonstrated that chronic exposure to drugs of abuse impairs goal-directed control over action selection indexed by the outcome-devaluation and specific Pavlovian to instrumental transfer procedures, suggesting this impairment might underpin addiction. However, there is currently only weak evidence for impaired goal-directed control in human drug users. Two experiments were undertaken in which treatment-seeking drug users and non-matched normative reference samples (controls) completed outcome-devaluation and specific Pavlovian to instrumental transfer procedures notionally translatable to animal procedures (Experiment 2 used a more challenging biconditional schedule). The two experiments found significant outcome-devaluation and specific Pavlovian to instrumental transfer effects overall and there was no significant difference between groups in the magnitude of these effects. Moreover, Bayes factor supported the null hypothesis for these group comparisons. Although limited by non-matched group comparisons and small sample sizes, the two studies suggest that treatment-seeking drug users have intact goal-directed control over action selection, adding uncertainty to already mixed evidence concerning the role of habit learning in human drug dependence. Neuro-interventions might seek to tackle goal-directed drug-seeking rather than habit formation in drug users. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  1. Investigation of the Direct Charge Transfer in Low Energy D2+ + H Collisions using Merged-Beams Technique

    Science.gov (United States)

    Romano, S. L.; Guillen, C. I.; Andrianarijaona, V. M.; Havener, C. C.

    2011-10-01

    The hydrogen - hydrogen (deuterium) molecular ion is the most fundamental ion-molecule two-electron system. Charge transfer (CT) for H2+ on H, which is one of the possible reaction paths for the (H-H2)+ system, is of special interest because of its contribution to H2 formation in the early universe, its exoergicity, and rich collision dynamics. Due to technical difficulty in making an atomic H target, the direct experimental investigations of CT for H2+ on H are sparse and generally limited to higher collision energies. The measurements of the absolute cross section of different CT paths for H2+ on H over a large range of collision energy are needed to benchmark theoretical calculations, especially the ones at low energies. The rate coefficient of CT at low energy is not known but may be comparable to other reaction rate coefficients in cold plasmas with H, H+, H2+, and H3+ as constituents. For instance, CT for H2+ on H and the following H3+ formation reaction H2+ + H2 → H + H3+ are clearly rate interdependent although it was always assumed that every ionization of H2 will lead to the formation of H3+. CT proceeds through dynamically coupled electronic, vibrational and rotational degrees of freedom. One can depict three paths, electronic CT, CT with nuclear substitution, and CT with dissociation. Electronic CT and CT with nuclear substitution in the H2+ on H collisions are not distinguishable by any quantum theory. Here we use the isotopic system (D2+ - H) to measure without ambiguity the electronic CT cross section by observing the H+ products. Using the ion-atom merged-beam apparatus at Oak Ridge National Laboratory, the absolute direct CT cross sections for D2+ + H from keV/u to meV/u collision energies have been measured. The molecular ions are extracted from an Electron-Cyclotron Resonance (ECR) ion source with a vibrational state distribution which is most likely determined by Frank-Condon transitions between ground state D2 and D2+. A ground-state H beam

  2. Post-treatment efficacy of discontinuous treatment with 300IR 5-grass pollen sublingual tablet in adults with grass pollen-induced allergic rhinoconjunctivitis

    DEFF Research Database (Denmark)

    Didier, A; Malling, H-J; Worm, Marcel

    2013-01-01

    Sustained efficacy over three pollen seasons of pre- and co-seasonal treatment with 300IR 5-grass pollen sublingual tablet has been demonstrated in adults with moderate-severe grass pollen-associated allergic rhinoconjunctivitis.......Sustained efficacy over three pollen seasons of pre- and co-seasonal treatment with 300IR 5-grass pollen sublingual tablet has been demonstrated in adults with moderate-severe grass pollen-associated allergic rhinoconjunctivitis....

  3. Pollen Competition as a Reproductive Isolation Barrier Represses Transgene Flow between Compatible and Co-Flowering Citrus Genotypes

    Science.gov (United States)

    Pons, Elsa; Navarro, Antonio; Ollitrault, Patrick; Peña, Leandro

    2011-01-01

    Background/Objective Despite potential benefits granted by genetically modified (GM) fruit trees, their release and commercialization raises concerns about their potential environmental impact, and the transfer via pollen of transgenes to cross-compatible cultivars is deemed to be the greatest source for environmental exposure. Information compiled from field trials on GM trees is essential to propose measures to minimize the transgene dispersal. We have conducted a field trial of seven consecutive years to investigate the maximum frequency of pollen-mediated crop-to-crop transgene flow in a citrus orchard, and its relation to the genetic, phenological and environmental factors involved. Methodology/Principal Findings Three different citrus genotypes carrying the uidA (GUS) tracer marker gene (pollen donors) and a non-GM self-incompatible contiguous citrus genotype (recipient) were used in conditions allowing natural entomophilous pollination to occur. The examination of 603 to 2990 seeds per year showed unexpectedly low frequencies (0.17–2.86%) of transgene flow. Paternity analyses of the progeny of subsets of recipient plants using 10 microsatellite (SSR) loci demonstrated a higher mating competence of trees from another non-GM pollen source population that greatly limited the mating chance of the contiguous cross-compatible and flowering-synchronized transgenic pollen source. This mating superiority could be explained by a much higher pollen competition capacity of the non-GM genotypes, as was confirmed through mixed-hand pollinations. Conclusions/Significance Pollen competition strongly contributed to transgene confinement. Based on this finding, suitable isolation measures are proposed for the first time to prevent transgene outflow between contiguous plantings of citrus types that may be extendible to other entomophilous transgenic fruit tree species. PMID:21991359

  4. Heat transfer

    International Nuclear Information System (INIS)

    Saad, M.A.

    1985-01-01

    Heat transfer takes place between material systems as a result of a temperature difference. The transmission process involves energy conversions governed by the first and second laws of thermodynamics. The heat transfer proceeds from a high-temperature region to a low-temperature region, and because of the finite thermal potential, there is an increase in entropy. Thermodynamics, however, is concerned with equilibrium states, which includes thermal equilibrium, irrespective of the time necessary to attain these equilibrium states. But heat transfer is a result of thermal nonequilibrium conditions, therefore, the laws of thermodynamics alone cannot describe completely the heat transfer process. In practice, most engineering problems are concerned with the rate of heat transfer rather than the quantity of heat being transferred. Resort then is directed to the particular laws governing the transfer of heat. There are three distinct modes of heat transfer: conduction, convection, and radiation. Although these modes are discussed separately, all three types may occur simultaneously

  5. Drought, pollen and nectar availability, and pollination success.

    Science.gov (United States)

    Waser, Nickolas M; Price, Mary V

    2016-06-01

    Pollination success of animal-pollinated flowers depends on rate of pollinator visits and on pollen deposition per visit, both of which should vary with the pollen and nectar "neighborhoods" of a plant, i.e., with pollen and nectar availability in nearby plants. One determinant of these neighborhoods is per-flower production of pollen and nectar, which is likely to respond to environmental influences. In this study, we explored environmental effects on pollen and nectar production and on pollination success in order to follow up a surprising result from a previous study: flowers of Ipomopsis aggregata received less pollen in years of high visitation by their hummingbird pollinators. A new analysis of the earlier data indicated that high bird visitation corresponded to drought years. We hypothesized that drought might contribute to the enigmatic prior result if it decreases both nectar and pollen production: in dry years, low nectar availability could cause hummingbirds to visit flowers at a higher rate, and low pollen availability could cause them to deposit less pollen per visit. A greenhouse experiment demonstrated that drought does reduce both pollen and nectar production by I. aggregata flowers. This result was corroborated across 6 yr of variable precipitation and soil moisture in four unmanipulated field populations. In addition, experimental removal of pollen from flowers reduced the pollen received by nearby flowers. We conclude that there is much to learn about how abiotic and biotic environmental drivers jointly affect pollen and nectar production and availability, and how this contributes to pollen and nectar neighborhoods and thus influences pollination success.

  6. Environmental behaviour of airborne Amaranthaceae pollen in the southern part of the Iberian Peninsula, and its role in future climate scenarios.

    Science.gov (United States)

    Cariñanos, Paloma; Alcázar, Purificación; Galán, Carmen; Domínguez, Eugenio

    2014-02-01

    The Amaranthaceae family includes a number of species which, through a series of specific adaptations, thrive in salty soils, arid environments and altered human settlements. Their ability to tolerate high temperatures favours summer flowering, giving rise to the widespread involvement of Amaranthaceae pollen grains in summer allergies, both in Mediterranean Europe and in areas with arid climates. This study analysed a 21-year set of historical airborne Amaranthaceae pollen records for an area located in the southern part of the Iberian Peninsula, in order to chart species' environmental reaction to changing climate conditions which occurred in the last decades. Airborne pollen data were collected from January 1991 to December 2011 using a Hirst-type volumetric impact sampler. Results showed that Amaranthaceae pollen remained in the atmosphere for over 6 months along the year, from early spring until early autumn. The annual Pollen Index ranged from barely 200 grains to almost 2000 grains, and was strongly influenced by rainfall during the flowering period, which prompted the development of new individuals and thus an increase in pollen production. A trend was noted towards increasingly early pollen peak dates; peaks were recorded in August-September in years with summer rainfall, but as early as May-June in years when over 50% of annual rainfall was recorded in the months prior to flowering. The gradual decline in the annual Pollen Index over later years is attributable not only to growing urbanisation of the area but also to a change in rainfall distribution pattern. High maximum temperatures in spring were also directly related to the peak date and the Pollen Index. This ability to adapt to changeable and occasionally stressful and restrictive, environmental conditions places Amaranthaceae at a competitive advantage with respect to other species sharing the same ecological niche. An increased presence of Amaranthaceae is likely to have a greater impact on future

  7. Pollen sources in the Bojanów forest complex identified on honeybee pollen load by microscopic analysis

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    Ernest Stawiarz

    2017-11-01

    Full Text Available The aim of this study was to determine sources of pollen for the honeybee in the Bojanów forest complex, Nowa Dęba Forest District (southeastern Poland. Sampling of pollen loads from bees extended from the beginning of May until the end of September 2016 and was carried out at 7-day intervals using pollen traps mounted at the entrance of beehives. A total of 73 pollen load samples were collected from the study area. Fifty-nine taxa from 31 plant families were identified in the analyzed material. From 4 to 21 taxa (average 9.5 were recorded in one sample. The pollen of Brassicaceae (“others”, Taraxacum type, Solidago type, and Rumex had the highest frequency in the pollen loads examined. Apart from these four taxa, pollen grains of Rubus type, Poaceae (“others”, Calluna, Fagopyrum, Trifolium repens s. l., Phacelia, Aster type, Melampyrum, Quercus, Cornus, and Veronica were recorded in the dominant pollen group. The forest habitat taxa that provided pollen rewards to honeybees in the Bojanów forest complex were the following: Rubus, Calluna, Prunus, Tilia, Frangula alnus, Pinus, Quercus, Cornus, Robinia pseudoacacia, Salix, and Vaccinium. Apart from forest vegetation, the species from meadows and wastelands adjacent to this forest complex, represented by Taraxacum, Rumex, Plantago, Poaceae, Trifolium repens, and Solidago, proved to be an important source of pollen. The study indicates that forest communities are a valuable source of pollen for pollinating insects from early spring through to late fall.

  8. Role of macrophage migration inhibitory factor (MIF in pollen-induced allergic conjunctivitis and pollen dermatitis in mice.

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    Yuka Nagata

    Full Text Available Pollen is a clinically important airborne allergen and one of the major causes of allergic conjunctivitis. A subpopulation of patients with atopic dermatitis (AD are also known to have exacerbated skin eruptions on the face, especially around the eyelids, after contact with pollen. This pollen-induced skin reaction is now known as pollen dermatitis. Macrophage migration inhibitory factor (MIF is a pluripotent cytokine that plays an essential role in allergic inflammation. Recent findings suggest that MIF is involved in several allergic disorders, including AD. In this study, MIF knockout (KO, MIF transgenic (Tg and WT littermate mice were immunized with ragweed (RW pollen or Japanese cedar (JC pollen and challenged via eye drops. We observed that the numbers of conjunctiva- and eyelid-infiltrating eosinophils were significantly increased in RW and JC pollen-sensitized MIF Tg compared with WT mice or MIF KO mice. The mRNA expression levels of eotaxin, interleukin (IL-5 and IL-13 were increased in pollen-sensitized eyelid skin sites of MIF Tg mice. An in vitro analysis revealed that high eotaxin expression was induced in dermal fibroblasts by MIF combined with stimulation of IL-4 or IL-13. This eotaxin expression was inhibited by the treatment with CD74 siRNA in fibroblasts. These findings indicate that MIF can induce eosinophil accumulation in the conjunctiva and eyelid dermis exposed to pollen. Therefore, targeted inhibition of MIF might result as a new option to control pollen-induced allergic conjunctivitis and pollen dermatitis.

  9. Can we improve pollen season definitions by using the symptom load index in addition to pollen counts?

    International Nuclear Information System (INIS)

    Bastl, Katharina; Kmenta, Maximilian; Geller-Bernstein, Carmi; Berger, Uwe; Jäger, Siegfried

    2015-01-01

    Airborne pollen measurements are the foundation of aerobiological research and provide essential raw data for various disciplines. Pollen itself should be considered a relevant factor in air quality. Symptom data shed light on the relationship of pollen allergy and pollination. The aim of this study is to assess the spatial variation of local, regional and national symptom datasets. Ten pollen season definitions are used to calculate the symptom load index for the birch and grass pollen seasons (2013–2014) in Austria. (1) Local, (2) regional and (3) national symptom datasets are used to examine spatial variations and a consistent pattern was found. In conclusion, national datasets are suitable for first insights where no sufficient local or regional dataset is available and season definitions based on percentages provide a practical solution, as they can be applied in regions with different pollen loads and produce more constant results. - Highlights: • The definition of the pollen season has an impact on the calculated symptom load. • Pollen season definitions based on percentages of total pollen are a practical solution. • The symptom load index is a robust tool to assess the allergy burden in a population. • Local, regional and national burdens of pollen allergy sufferers are comparable. - The symptom load index is a robust tool to assess the allergy burden in a population. Local, regional and national burdens of pollen allergy sufferers are comparable

  10. Food for Pollinators: Quantifying the Nectar and Pollen Resources of Urban Flower Meadows.

    Science.gov (United States)

    Hicks, Damien M; Ouvrard, Pierre; Baldock, Katherine C R; Baude, Mathilde; Goddard, Mark A; Kunin, William E; Mitschunas, Nadine; Memmott, Jane; Morse, Helen; Nikolitsi, Maria; Osgathorpe, Lynne M; Potts, Simon G; Robertson, Kirsty M; Scott, Anna V; Sinclair, Frazer; Westbury, Duncan B; Stone, Graham N

    2016-01-01

    Planted meadows are increasingly used to improve the biodiversity and aesthetic amenity value of urban areas. Although many 'pollinator-friendly' seed mixes are available, the floral resources these provide to flower-visiting insects, and how these change through time, are largely unknown. Such data are necessary to compare the resources provided by alternative meadow seed mixes to each other and to other flowering habitats. We used quantitative surveys of over 2 million flowers to estimate the nectar and pollen resources offered by two exemplar commercial seed mixes (one annual, one perennial) and associated weeds grown as 300m2 meadows across four UK cities, sampled at six time points between May and September 2013. Nectar sugar and pollen rewards per flower varied widely across 65 species surveyed, with native British weed species (including dandelion, Taraxacum agg.) contributing the top five nectar producers and two of the top ten pollen producers. Seed mix species yielding the highest rewards per flower included Leontodon hispidus, Centaurea cyanus and C. nigra for nectar, and Papaver rhoeas, Eschscholzia californica and Malva moschata for pollen. Perennial meadows produced up to 20x more nectar and up to 6x more pollen than annual meadows, which in turn produced far more than amenity grassland controls. Perennial meadows produced resources earlier in the year than annual meadows, but both seed mixes delivered very low resource levels early in the year and these were provided almost entirely by native weeds. Pollen volume per flower is well predicted statistically by floral morphology, and nectar sugar mass and pollen volume per unit area are correlated with flower counts, raising the possibility that resource levels can be estimated for species or habitats where they cannot be measured directly. Our approach does not incorporate resource quality information (for example, pollen protein or essential amino acid content), but can easily do so when suitable data

  11. Investigation of heterogeneous ice nucleation in pollen suspensions and washing water

    Science.gov (United States)

    Dreischmeier, Katharina; Budke, Carsten; Koop, Thomas

    2014-05-01

    Biological particles such as pollen often show ice nucleation activity at temperatures higher than -20 °C. Immersion freezing experiments of pollen washing water demonstrate comparable ice nucleation behaviour as water containing the whole pollen bodies (Pummer et al., 2012). It was suggested that polysaccharide molecules leached from the grains are responsible for the ice nucleation. Here, heterogeneous ice nucleation in birch pollen suspensions and their washing water was investigated by two different experimental methods. The optical freezing array BINARY (Bielefeld Ice Nucleation ARraY) allows the direct observation of freezing of microliter-sized droplets. The IN spectra obtained from such experiments with birch pollen suspensions over a large concentration range indicate several different ice nucleation active species, two of which are present also in the washing water. The latter was probed also in differential scanning calorimeter (DSC) experiments of emulsified sub-picoliter droplets. Due to the small droplet size in the emulsion samples and at small concentration of IN in the washing water, such DSC experiments can exhibit the ice nucleation behaviour of a single nucleus. The two heterogeneous freezing signals observed in the DSC thermograms can be assigned to two different kinds of ice nuclei, confirming the observation from the BINARY measurements, and also previous studies on Swedish birch pollen washing water (Augustin et al., 2012). The authors gratefully acknowledge funding by the German Research Foundation (DFG) through the project BIOCLOUDS (KO 2944/1-1) and through the research unit INUIT (FOR 1525) under KO 2944/2-1. We particularly thank our INUIT partners for fruitful collaboration and sharing of ideas and IN samples. S. Augustin, H. Wex, D. Niedermeier, B. Pummer, H. Grothe, S. Hartmann, L. Tomsche, T. Clauss, J. Voigtländer, K. Ignatius, and F. Stratmann, Immersion freezing of birch pollen washing water, Atmos. Chem. Phys., 13, 10989

  12. ROPES reveals past land cover and pollen productivity estimates from single pollen records

    Science.gov (United States)

    Theuerkauf, Martin; Couwenberg, John

    2018-04-01

    Quantitative reconstructions of past vegetation cover commonly require pollen productivity estimates (PPEs). PPEs are calibrated in extensive and rather cumbersome surface-sample studies, and are so far only available for selected regions. Moreover, it may be questioned whether present-day pollen-landcover relationships are valid for palaeo-situations. We here introduce the ROPES approach that simultaneously derives PPEs and mean plant abundances from single pollen records. ROPES requires pollen counts and pollen accumulation rates (PARs, grains cm-2 year-1). Pollen counts are used to reconstruct plant abundances following the REVEALS approach. The principle of ROPES is that changes in plant abundance are linearly represented in observed PAR values. For example, if the PAR of pine doubles, so should the REVEALS reconstructed abundance of pine. Consequently, if a REVEALS reconstruction is ‘correct’ (i.e. ‘correct’ PPEs are used) the ratio ‘PAR over REVEALS’ is constant for each taxon along all samples of a record. With incorrect PPEs, the ratio will instead vary. ROPES starts from random (likely incorrect) PPEs, but then adjusts them using an optimization algorithm with the aim to minimize variation in the ‘PAR over REVEALS’ ratio across the record. ROPES thus simultaneously calculates mean plant abundances and PPEs. We illustrate the approach with test applications on nine synthetic pollen records. The results show that good performance of ROPES requires data sets with high underlying variation, many samples and low noise in the PAR data. ROPES can deliver first landcover reconstructions in regions for which PPEs are not yet available. The PPEs provided by ROPES may then allow for further REVEALS-based reconstructions. Similarly, ROPES can provide insight in pollen productivity during distinct periods of the past such as the Lateglacial. We see a potential to study spatial and temporal variation in pollen productivity for example in relation to site

  13. Considerations for the preparation of peat samples for palynology, and for the counting of pollen and non-pollen palynomorphs

    Directory of Open Access Journals (Sweden)

    F.M. Chambers

    2011-09-01

    Full Text Available Peat deposits are valuable archives for studying palaeoclimate, the history of local and regional vegetation, and human impact. The most widely applied laboratory analytical technique has been palynology (pollen analysis, which is often limited to the study of pollen and a few easily recognisable spores; however, a variety of other microfossils can be studied in peat deposits and can provide information on past environmental conditions. Among the so-called non-pollen palynomorphs (NPPs are fungal and algal spores that can be used as indicators for local hydrological changes and trophic conditions. This article provides an overview of aspects to consider and sample preparation methods for pollen, spores and other non-pollen palynomorph microfossils in peat deposits; advice on aids to pollen identification and counting; and a brief guide to the range of NPPs that can be counted from prepared subfossil-pollen microslides.

  14. Comparative and Evolutionary Analysis of Grass Pollen Allergens Using Brachypodium distachyon as a Model System.

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    Akanksha Sharma

    Full Text Available Comparative genomics have facilitated the mining of biological information from a genome sequence, through the detection of similarities and differences with genomes of closely or more distantly related species. By using such comparative approaches, knowledge can be transferred from the model to non-model organisms and insights can be gained in the structural and evolutionary patterns of specific genes. In the absence of sequenced genomes for allergenic grasses, this study was aimed at understanding the structure, organisation and expression profiles of grass pollen allergens using the genomic data from Brachypodium distachyon as it is phylogenetically related to the allergenic grasses. Combining genomic data with the anther RNA-Seq dataset revealed 24 pollen allergen genes belonging to eight allergen groups mapping on the five chromosomes in B. distachyon. High levels of anther-specific expression profiles were observed for the 24 identified putative allergen-encoding genes in Brachypodium. The genomic evidence suggests that gene encoding the group 5 allergen, the most potent trigger of hay fever and allergic asthma originated as a pollen specific orphan gene in a common grass ancestor of Brachypodium and Triticiae clades. Gene structure analysis showed that the putative allergen-encoding genes in Brachypodium either lack or contain reduced number of introns. Promoter analysis of the identified Brachypodium genes revealed the presence of specific cis-regulatory sequences likely responsible for high anther/pollen-specific expression. With the identification of putative allergen-encoding genes in Brachypodium, this study has also described some important plant gene families (e.g. expansin superfamily, EF-Hand family, profilins etc for the first time in the model plant Brachypodium. Altogether, the present study provides new insights into structural characterization and evolution of pollen allergens and will further serve as a base for their

  15. Preparation of Highly Dispersed Reduced Graphene Oxide Decorated with Chitosan Oligosaccharide as Electrode Material for Enhancing the Direct Electron Transfer of Escherichia coli.

    Science.gov (United States)

    Luo, Zhimin; Yang, Dongliang; Qi, Guangqin; Yuwen, Lihui; Zhang, Yuqian; Weng, Lixing; Wang, Lianhui; Huang, Wei

    2015-04-29

    Water-dispersed reduced graphene oxide/chitosan oligosaccharide (RGO-CTSO) was prepared by chemical reduction of graphene oxide and synchronous functionalization with biocompatible chitosan oligosaccharide (CTSO). ζ potential measurement indicated that RGO-CTSO was highly stable in the acidic aqueous solution. RGO-CTSO was used to modify glassy carbon electrode (GCE) as the growth template of Escherichia coli (E. coli). The enhanced direct electron transfer of E. coli on the RGO-CTSO-modified GCE was studied by cyclic voltammetry. Compared with GCE or RGO-modified GCE, RGO-CTSO-modified GCE was more suitable for the adhesion growth of E. coli to improve direct electron transfer. The biocompatibility and versatility of RGO-CTSO made it promising for use as an anode material in microbial fuel cells.

  16. Identification of sweet chesnut pollen in bee pollen pellet using using molecular analysis.

    Directory of Open Access Journals (Sweden)

    Jana Žiarovská

    2015-10-01

    Full Text Available Castanea sativa posses many characteristics that are used by human for different purposes, not only as a part of the food. One of them is the utilization of the sweet chesnut pollen for its pharmacological benefits. Actually, no information about the DNA based identification of the sweet chesnut exist. Here, an identification of Castanea sativa based on the specific DNA fragment amplification is described for the first time. Sweet chesnut identification was performed in the very complex sample of bee pollen pellets that were identified as to contain sweet chesnut pollen grains by morphological analysis. First, bioinformatic analysis was performed to find a Castanea sativa conservative part of galactol synthase gene. BLAST alignment of the CDS of GolS1 gene was performed by BLASTtn against plants nucleotide sequences in the NCBI database to ensure for the specifity or existing nucleotide differences. Then, specific primers were subsequently designed and PCR amplification was performed. All the PCRs have run in duplicates for pollen pellet sample and two independent samples of Castanea sativa pure pollen. Restriction cleavage of the PCR amplified fragment was performed to confirm the specifity of the obtained PCR product with the positive confirmation as the predicted three restriction fragments were obtained that fully correspond by the length to those from virtual clevage. Restriction endonuclease Hpy166II was used in restriction cleavage analysis. Castanea sativa pollen grains were confirmed reliable in multifloral pollen pellet by PCR and this approach has the potential to be used effectively for the authentication purposes of sweet chesnut.

  17. Supercapacitive Biosolar Cell Driven by Direct Electron Transfer between Photosynthetic Membranes and CNT Networks with Enhanced Performance

    DEFF Research Database (Denmark)

    Pankratov, Dmitry; Pankratova, Galina; Dyachkova, Tatiana P.

    2017-01-01

    enabled a 1.5-fold enhancement in photocurrent density. This system offers more advantages including a reduced charge-transfer resistance, a lower open-circuit potential, and an improved cell stability. More remarkably, the average power density of the optimized cells was 250 times higher than...

  18. Flotation preferentially selects saccate pollen during conifer pollination.

    Science.gov (United States)

    Leslie, Andrew B

    2010-10-01

    • Among many species of living conifers the presence of pollen with air bladders (saccate pollen) is strongly associated with downward-facing ovules and the production of pollination drops. This combination of features enables saccate pollen grains captured in the pollination drop to float upwards into the ovule. Despite the importance of this mechanism in understanding reproduction in living conifers and in extinct seed plants with similar morphologies, experiments designed to test its effectiveness have yielded equivocal results. • In vitro and in vivo pollination experiments using saccate and nonsaccate pollen were performed using modeled ovules and two Pinus species during their natural pollination period. • Buoyant saccate pollen readily floated through aqueous droplets, separating these grains from nonbuoyant pollen and spores. Ovules that received saccate pollen, nonsaccate pollen or a mixture of both all showed larger amounts and higher proportions of saccate pollen inside ovules after drop secretion. • These results demonstrate that flotation is an effective mechanism of pollen capture and transport in gymnosperms, and suggest that the prevalence of saccate grains and downward-facing ovules in the evolutionary history of seed plants is a result of the widespread use of this mechanism.

  19. Cell Wall Composition, Biosynthesis and Remodeling during Pollen Tube Growth

    Directory of Open Access Journals (Sweden)

    Jean-Claude Mollet

    2013-03-01

    Full Text Available The pollen tube is a fast tip-growing cell carrying the two sperm cells to the ovule allowing the double fertilization process and seed setting. To succeed in this process, the spatial and temporal controls of pollen tube growth within the female organ are critical. It requires a massive cell wall deposition to promote fast pollen tube elongation and a tight control of the cell wall remodeling to modify the mechanical properties. In addition, during its journey, the pollen tube interacts with the pistil, which plays key roles in pollen tube nutrition, guidance and in the rejection of the self-incompatible pollen. This review focuses on our current knowledge in the biochemistry and localization of the main cell wall polymers including pectin, hemicellulose, cellulose and callose from several pollen tube species. Moreover, based on transcriptomic data and functional genomic studies, the possible enzymes involved in the cell wall remodeling during pollen tube growth and their impact on the cell wall mechanics are also described. Finally, mutant analyses have permitted to gain insight in the function of several genes involved in the pollen tube cell wall biosynthesis and their roles in pollen tube growth are further discussed.

  20. [Allergic responses to date palm and pecan pollen in Israel].

    Science.gov (United States)

    Waisel, Y; Keynan, N; Gil, T; Tayar, D; Bezerano, A; Goldberg, A; Geller-Bernstein, C; Dolev, Z; Tamir, R; Levy, I

    1994-03-15

    Date palm (Phoenix dactylifera) and pecan (Carya illinoensis) trees are commonly planted in Israel for fruit, for shade, or as ornamental plants. Pollen grains of both species are allergenic; however, the extent of exposure to such pollen and the incidence of allergic response have not been studied here. We therefore investigated skin-test responses to pollen extracts of 12 varieties of palm and 9 of pecan in 705 allergic patients living in 3 cities and 19 rural settlements. Sensitivity to the pollen extracts of both species was much higher among residents of rural than of urban communities. Moreover, there was a definite relationship between the abundance of these trees in a region and the incidence of skin responders to their pollen. Sensitivity was frequent in settlements rich in these 2 species, such as those with nearby commercial date or pecan plantations. In general, sensitivity to date pollen extracts was lower than to pecan. However, differences in skin responses to pollen extracts of various clones were substantiated. Air sampling revealed that pollen pollution decreased considerably with distance from the trees. At approximately 100 m from a source concentrations of airborne pollen were low. Since planting of male palm and pecan trees in population centers would increase pollen pollution, it should be avoided.

  1. Pollen Ultrastructure of Genus Dendrobium Orchids as a Learning Resource

    Directory of Open Access Journals (Sweden)

    Lika Dwi Apriani

    2016-11-01

    Full Text Available Anggrek genus Dendrobium merupakan salah satu genus dari divisi spermatophyta yang merupakan kelompok tumbuhan yang berkembang dengan menggunakan biji. Tumbuhan berbiji tentu memiliki bunga sebagai alat perkembangan generatifnya. Perkembangan generatif pada bunga artinya pertemuan antara sel gamet jantan dan sel gamet betina. Sel gamet betina pada tumbuhan dihasilkan oleh putik, sedangkan sel gamet jantan disebut serbuk sari atau pollen. Genus Dendrobium merupakan salah satu kekayaan alam Indonesia, jumlahnya diperkirakan mencapai 275 spesies. Penelitian ini bertujuan untuk mengetahui bagaimana ultrastruktur pollen anggrek genus Dendrobium dari sepuluh spesies yang diamati menggunakan SEM. Jenis penelitian ini adalah deskriptif kualitatif. Hasil penelitian menunjukkan unit pollen untuk semua spesies yaitu kategori pollinia, sedangkan untuk polaritas pollen adalah apolar. Jenis aperture kesepuluh spesies yang diamati mempunyai aperture dengan pola yang tidak beraturan dan lebih dari enam yang disebut colpate. Bentuk pollen dari semua spesies yang diteliti bentuknya adalah subprolate hingga prolate dan ukuran pollen termasuk dalam kategori minuta hingga media. Ornamentasi pollen atau skluptur pollen tidak teridentifikasi dikarenakan ukuran pollen yang terlalu kecil, permukaan pollen terlihat kurang jelas. Sumber belajar yang digunakan adalah atlas.

  2. [The development of pollen grains and formation of pollen tubes in higher plants : I. Quantitative measurements of the DNA-content of generative and vegetative nuclei in the pollen grain and pollen tube of Petunia hybrida mutants].

    Science.gov (United States)

    Hesemann, C U

    1971-01-01

    The DNA-content of generative and vegetative nuclei in mature pollen grains of four Petunia hybrida mutants was determined by cytophotometry. In addition the DNA-content of generative and vegetative nuclei in the pollen tube of two of these four mutants (virescens-2 n and ustulata-2 n) was cytophotometrically measured.The DNA-values found in the generative nuclei indicate that the DNA-replication continues in the mature pollen grain and comes to an end only after the migration of the nuclei into the pollen tube. These data are in disagreement with the results of DNA-measurements described for a limited number of other species which all show completion of DNA-synthesis during the maturation stage of the pollen grains.The vegetative nuclei of the four Petunia mutants studied show significant differences in the onset of the degenerative phase. Extreme variation is manifested in the ustulata-2 n mutant in which the degeneration of nuclei may reach the final stage in the maturing pollen grain. However in this mutant vegetative nuclei with an unaltered DNA-content may also be demonstrated in the pollen tube. Some of the vegetative nuclei in the pollen tube of ustulata-2 n exhibit an increased amount of DNA which could be the result of differential DNA-replication in the vegetative nuclei. The decrease of the DNA-content in a certain fraction of the vegetative nuclei in the maturing pollen grain does not agree with observations made in other species by several authors who report DNA constancy until the pollen grain is fully mature.The data obtained from the analysis of the four Petunia hybrida mutants point to an important role of the vegetative nucleus in the development of the pollen tube. The Petunia hybrida mutants may be regarded as especially favourable material for investigations concerning the function of the vegetative cell in the development of the pollen grain and pollen tube.

  3. Exposure to environmentally-relevant levels of ozone negatively influence pollen and fruit development.

    Science.gov (United States)

    Gillespie, Colin; Stabler, Daniel; Tallentire, Eva; Goumenaki, Eleni; Barnes, Jeremy

    2015-11-01

    A combination of in vitro and in vivo studies on tomato (Lycopersicon esculentum Mill. cv. Triton) revealed that environmentally-relevant levels of ozone (O3) pollution adversely affected pollen germination, germ tube growth and pollen-stigma interactions - pollen originating from plants raised in charcoal-Purafil(®) filtered air (CFA) exhibited reduced germ tube development on the stigma of plants exposed to environmentally-relevant levels of O3. The O3-induced decline in in vivo pollen viability was reflected in increased numbers of non-fertilized and fertilized non-viable ovules in immature fruit. Negative effects of O3 on fertilization occurred regardless of the timing of exposure, with reductions in ovule viability evident in O3 × CFA and CFA × O3 crossed plants. This suggests O3-induced reductions in fertilization were associated with reduced pollen viability and/or ovule development. Fruit born on trusses independently exposed to 100 nmol mol(-1) O3 (10 h d(-1)) from flowering exhibited a decline in seed number and this was reflected in a marked decline in the weight and size of individual fruit - a clear demonstration of the direct consequence of the effects of the pollutant on reproductive processes. Ozone exposure also resulted in shifts in the starch and ascorbic acid (Vitamin C) content of fruit that were consistent with accelerated ripening. The findings of this study draw attention to the need for greater consideration of, and possibly the adoption of weightings for the direct impacts of O3, and potentially other gaseous pollutants, on reproductive biology during 'risk assessment' exercises. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Pollen-based reconstruction of Holocene climate variability in the Eifel region evaluated with stable isotopes

    Science.gov (United States)

    Kühl, Norbert; Moschen, Robert; Wagner, Stefanie

    2010-05-01

    sediments might strongly react to anthropogenic deforestation, as carbon isotope time series from the adjacent Lake Holzmaar suggest. Reconstructions based on pollen with the pdf-method are robust to the human impact during the last 4000 years, but do not reproduce the fine scale climate variability that can be derived from the stable isotope series (Kühl et al., in press). In contrast, reconstructions on the basis of pollen data show relatively pronounced climate variability (here: January temperature) during the Mid-Holocene, which is known from many other European records. The oxygen isotope time series as available now indicate that at least some of the observed variability indeed reflects climate variability. However, stable carbon isotopes show little concordance. At this stage our results point in the direction that 1) the isotopic composition might reflect a shift in influencing factors during the Holocene, 2) climate trends can robustly be reconstructed with the pdf method and 3) fine scale climate variability can potentially be reconstructed using the pdf-method, given that climate sensitive taxa at their distribution limit are present. The latter two conclusions are of particular importance for the reconstruction of climatic trends and variability of interglacials older than the Holocene, when sites are rare and pollen is often the only suitable proxy in terrestrial records. Kühl, N., Moschen, R., Wagner, S., Brewer, S., Peyron, O., in press. A multiproxy record of Late Holocene natural and anthropogenic environmental change from the Sphagnum peat bog Dürres Maar, Germany: implications for quantitative climate reconstructions based on pollen. J. Quat. Sci., DOI: 10.1002/jqs.1342. Available online. Moschen, R., Kühl, N., Rehberger, I., Lücke, A., 2009. Stable carbon and oxygen isotopes in sub-fossil Sphagnum: Assessment of their applicability for palaeoclimatology. Chemical Geology 259, 262-272.

  5. Quality of durable cookies enriched with rape bee pollen

    Directory of Open Access Journals (Sweden)

    Miriam Solgajová

    2014-03-01

    Full Text Available The objective of this study was to enrich durable cookies with different additions of rape (Brassica napus var. napus bee pollen to increase nutritional properties of cookie samples and to improve technological and sensorial properties as well. Bee pollen is an important raw material due to its nutritional and functional properties. Cookie samples were prepared by substituting wheat flour with rape bee pollen in the amount of 16 % (1 g of bee pollen per cookie and 32 % (2 g of bee pollen per cookie using bee pollen from two localities Lenártovce and Nové Zámky. In baked samples beside sensory properties also chemical parameters and technological parameters of cookies were evaluated. It was found out that with the gradual addition of rape bee pollen the amount of ash content increased and the highest ash content was analysed in variants II and IV (0.71 and 0.77 % using 32 % addition of rape bee pollen. In terms of reducing sugars, addition of bee pollen caused that the content of reducing sugars in the products increased slightly. The highest reducing sugar content was determined in variant II. (24.59 %. On the other hand amount of crude protein the most considerably raised by addition of 2 g of pollen per cookie. The highest content of crude protein was analysed in variants II and IV (8.72 and 9.00 %. From the results of a linear models in which the dependent variables were the ash, crude protein and moisture it was determined the significant effect (p <0.05 only of the pollen addition. In the case of the model with the dependent variable reducing sugars it was found out significant effect (p<0.0001 of pollen addition and locality and their interactions. With the gradual addition of bee pollen values of technological parameters such as diameter and weight of cookies increased and thickness of products decreased. Based on sensory scores using a 9-point Hedonic scale the best sensorial acceptability (7.4 was found in variant I (1 g of bee

  6. Comparative Analysis of the Arabidopsis Pollen Transcriptome

    Czech Academy of Sciences Publication Activity Database

    Honys, David; Twell, D.

    2003-01-01

    Roč. 132, - (2003), s. 640ů652 ISSN 0032-0889 R&D Projects: GA AV ČR IAA5038207 Grant - others:Royal Society(GB) NATO Postdoctoral Fellowship (to D.H.) Institutional research plan: CEZ:AV0Z5038910; CEZ:MSM 113100003 Keywords : transcriptome profiling * Arabidopsis pollen * male gametophyte Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.634, year: 2003

  7. The direct cost of traumatic secretion transfer in hermaphroditic land snails: individuals stabbed with a love dart decrease lifetime fecundity.

    Science.gov (United States)

    Kimura, Kazuki; Chiba, Satoshi

    2015-04-07

    Several taxa of simultaneously hermaphroditic land snails exhibit a conspicuous mating behaviour, the so-called shooting of love darts. During mating, such land snail species transfer a specific secretion by stabbing a mating partner's body with the love dart. It has been shown that sperm donors benefit from this traumatic secretion transfer, because the secretions manipulate the physiology of a sperm recipient and increase the donors' fertilization success. However, it is unclear whether reception of dart shooting is costly to the recipients. Therefore, the effect of sexual conflict and antagonistic arms races on the evolution of traumatic secretion transfer in land snails is still controversial. To examine this effect, we compared lifetime fecundity and longevity between the individuals that received and did not receive dart shooting from mating partners in Bradybaena pellucida. Our experiments showed that the dart-receiving snails suffered reduction in lifetime fecundity and longevity. These results suggest that the costly mating behaviour, dart shooting, generates conflict between sperm donors and recipients and that sexually antagonistic arms races have contributed to the diversification of the morphological and behavioural traits relevant to dart shooting. Our findings also support theories suggesting a violent escalation of sexual conflict in hermaphroditic animals. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  8. Citrus allergy from pollen to clinical symptoms.

    Directory of Open Access Journals (Sweden)

    Rosa Anna Iorio

    Full Text Available Allergy to citrus fruits is often associated with pollinosis and sensitization to other plants due to a phenomenon of cross-reactivity. The aims of the present study were to highlight the cross-reactivity among citrus and the major allergenic pollens/fruits, throughout clinical and molecular investigations, and to evaluate the sensitization frequency to citrus fruits in a population of children and adults with pollinosis. We found a relevant percentage of sensitisation (39% to citrus fruits in the patients recruited and in all of them the IgE-mediated mechanism has been confirmed by the positive response to the prick-to-prick test. RT-PCR experiments showed the expression of Cit s 1, Cit s 3 and a profilin isoform, already described in apple, also in Citrus clementine pollen. Data of multiple sequence alignments demonstrated that Citrus allergens shared high percentage identity values with other clinically relevant species (i.e. Triticum aestivum, Malus domestica, confirming the possible cross-allergenicity citrus/grasses and citrus/apple. Finally, a novelty of the present work has been the expression of two phospholipaseA2 isoforms (PLA2 α and β in Citrus as well as in Triticum pollens; being PLA2 able to generate pro-inflammatory factors, this enzyme could participate in the activation of the allergenic inflammatory cascade.

  9. Pollen-gamma irradiation on pineapple and pollination using irradiated pollen

    International Nuclear Information System (INIS)

    Benega, R.; Cisneros, A.; Martinez, J.; Arias, E.; Yabor, L.; Isidron, M.; Castillo, E.; Fernandez, J.

    1997-01-01

    In order to try to induce haploid plants, pineapple (Ananas comosus (L.) ;err.) pollen grains were gamma-rays irradiated with a Co 60 source at rates of doses from 0 to 300 Gy. The effect of gamma-rays on the generative-nucleus division and vitro pollen viability as well as, seed contents and plantlets obtained after pollinations was analysed. The were reducing in the division frequencies of generative nucleus at all assayed doses. The LD50 was achieved among 200 and 250 Gy. There were not differences on pollen viability in the rates of assayed doses. Seed contents were dose-dependent. The percentages of seed full and seed containing only embryos decreases at increasing of irradiation doses. Contrary effect was observed on the seed empty. Some plantlets regenerated from the different irradiation doses showed phenotypes with small and leaves and short inter nodes

  10. A design tool for direct and non-stochastic calculations of near-field radiative transfer in complex structures: The NF-RT-FDTD algorithm

    Science.gov (United States)

    Didari, Azadeh; Pinar Mengüç, M.

    2017-08-01

    Advances in nanotechnology and nanophotonics are inextricably linked with the need for reliable computational algorithms to be adapted as design tools for the development of new concepts in energy harvesting, radiative cooling, nanolithography and nano-scale manufacturing, among others. In this paper, we provide an outline for such a computational tool, named NF-RT-FDTD, to determine the near-field radiative transfer between structured surfaces using Finite Difference Time Domain method. NF-RT-FDTD is a direct and non-stochastic algorithm, which accounts for the statistical nature of the thermal radiation and is easily applicable to any arbitrary geometry at thermal equilibrium. We present a review of the fundamental relations for far- and near-field radiative transfer between different geometries with nano-scale surface and volumetric features and gaps, and then we discuss the details of the NF-RT-FDTD formulation, its application to sample geometries and outline its future expansion to more complex geometries. In addition, we briefly discuss some of the recent numerical works for direct and indirect calculations of near-field thermal radiation transfer, including Scattering Matrix method, Finite Difference Time Domain method (FDTD), Wiener Chaos Expansion, Fluctuating Surface Current (FSC), Fluctuating Volume Current (FVC) and Thermal Discrete Dipole Approximations (TDDA).

  11. Urtica dioica pollen allergy: Clinical, biological, and allergomics analysis.

    Science.gov (United States)

    Tiotiu, Angelica; Brazdova, Andrea; Longé, Cyril; Gallet, Patrice; Morisset, Martine; Leduc, Virginie; Hilger, Christiane; Broussard, Cédric; Couderc, Rémy; Sutra, Jean-Pierre; Sénéchal, Hélène; Poncet, Pascal

    2016-11-01

    The most emblematic members of Urticaceae at allergic risk level are wall pellitories (Parietaria), whereas nettle (Urtica) pollen is considered as poorly allergenic. No allergen from nettle pollen has yet been characterized, whereas 4 are listed for Parietaria pollen by the International Union of Immunological Societies. Clinical and biological profiles of 2 adult men who developed symptoms against nettle pollen and/or leaves were studied. To characterize the allergic reaction and identify the potential nettle pollen sensitizing allergens. IgE-mediated reaction to nettle pollen extract was evaluated by skin prick test, immunoassay, nasal provocation, and basophil activation test. To characterize specific nettle pollen allergens, an allergomic (IgE immunoproteomic) analysis was performed combining 1- and 2-dimensional electrophoresis, IgE immunoblots of nettle pollen extract, identification of allergens by mass spectrometry, and database queries. The results of biological and immunochemical analyses revealed that the allergic rhinitis was due to Urtica dioica pollen in both patients. The allergomic analysis of nettle pollen extract allowed the characterization of 4 basic protein allergens: a thaumatin-like protein (osmotin) with a relative molecular mass of 27 to 29 kDa, a pectinesterase (relative molecular mass, 40 kDa), and 2 other basic proteins with relative molecular masses of 14 to 16 kDa and 43 kDa. There is no or only very weak allergen associations between pellitory and nettle pollen. Exposure to nettle pollen can be responsible of allergic symptoms, and several allergens were characterized. Unravelling the allergens of this underestimated allergy might help to improve diagnosis and care for patients, to predict cross-reactivities and design adapted specific immunotherapy. Copyright © 2016 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  12. MICROBIOTA OF PINUS POLLEN AS ADJUVANT FACTOR OF ALLERGY

    OpenAIRE

    Tetiana Shevtsova; Miroslava Kačániová; Jana Petrová; Ján Brindza; Kateryna Garkava

    2016-01-01

    Bacteria, their endotoxin and mold found on pollen can be a reason of respiratory symptoms in sensitized individuals. This question concerns an anemophilous pollen more acute. In this work quantitative by dilution plating method and qualitative microbial analysis by MALDI-TOF MS Biotyper of pollen and other plants organs of Pinus sylvestris L., P. nigra Arnold, P. mugo Turra, P. armandii Franch., P. wallichiana A.B. Jacks from Nitra, Slovakia are performed which shows quantitative and species...

  13. Securing maximum diversity of Non Pollen Palynomorphs in palynological samples

    DEFF Research Database (Denmark)

    Enevold, Renée; Odgaard, Bent Vad

    2015-01-01

    Palynology is no longer synonymous with analysis of pollen with the addition of a few fern spores. A wide range of Non Pollen Palynomorphs are now described and are potential palaeoenvironmental proxies in the palynological surveys. The contribution of NPP’s has proven important to the interpreta......Palynology is no longer synonymous with analysis of pollen with the addition of a few fern spores. A wide range of Non Pollen Palynomorphs are now described and are potential palaeoenvironmental proxies in the palynological surveys. The contribution of NPP’s has proven important...

  14. Fraxinus pollen as a source of environmental pollution

    Directory of Open Access Journals (Sweden)

    María Fernández-González

    2016-06-01

    Full Text Available In Southern Europe there are but a few studies focused on the allergenic impact of ash (Fraxinus pollen as a result of its scarce distribution. In the city of Ourense this type of pollen represents 2% of the total atmospheric pollen recorded. The goal of this study is to determine the atmospheric concentrations of Fraxinus pollen and its allergen in Ourense’s atmosphere in 2015, and to assess their relationship with the main meteorological variables. The aim is to assess whether the pollen counts match the actual exposure conditions for allergen-sensitive patients. A Lanzoni VPPS-2000 volumetric sampler was used for pollen sampling, whereas a Burkard Cyclone sampler was used for allergen detection.The flowering period of Fraxinus was long, having a duration of 76 days between the third week of January and the rst week of April as consequence of the asynchronous flowering of the different species growing in the study area. The presence of the ash allergen in the atmosphere can be detected using the main olive tree allergen, Ole e 1. Our study indicates that the combination of pollen counts and allergen quanti cation should be contemplated to estimate the real exposure of sensitive people. In the case of Fraxinus pollen, there may be allergy risk periods before and after the occurrence of the highest pollen concentrations in the atmosphere as a result of special rain and humidity conditions during its flowering period.

  15. Pollen Flora of Yuenyang Lake Nature Preserve, Taiwan (IV

    Directory of Open Access Journals (Sweden)

    Yu-Fa Wang

    2002-06-01

    Full Text Available Yuenyang Lake is an acidic lake situated within a nature preserve in northern Taiwan. The pollen of nineteen taxa, belonging to five families, was collected from this nature preserve and investigated with light and scanning electron microscopy. The results of this investigation are supplementary work to the previous publications in this journal (Chen and Wang, 1999, 2001; Wang and Chen, 2001. A total of 4 pollen classes were identified on the basis of the aperture on the pollen wall: 3-colpate, 6-colpate, 3-colporate, and 4-7-colporate pollen. These results could be useful in the reconstruction of vegetation history around the Yuenyang Lake.

  16. A DNA barcoding approach to characterize pollen collected by honeybees.

    Directory of Open Access Journals (Sweden)

    Andrea Galimberti

    Full Text Available In the present study, we investigated DNA barcoding effectiveness to characterize honeybee pollen pellets, a food supplement largely used for human nutrition due to its therapeutic properties. We collected pollen pellets using modified beehives placed in three zones within an alpine protected area (Grigna Settentrionale Regional Park, Italy. A DNA barcoding reference database, including rbcL and trnH-psbA sequences from 693 plant species (104 sequenced in this study was assembled. The database was used to identify pollen collected from the hives. Fifty-two plant species were identified at the molecular level. Results suggested rbcL alone could not distinguish among congeneric plants; however, psbA-trnH identified most of the pollen samples at the species level. Substantial variability in pollen composition was observed between the highest elevation locality (Alpe Moconodeno, characterized by arid grasslands and a rocky substrate, and the other two sites (Cornisella and Ortanella at lower altitudes. Pollen from Ortanella and Cornisella showed the presence of typical deciduous forest species; however in samples collected at Ortanella, pollen of the invasive Lonicera japonica, and the ornamental Pelargonium x hortorum were observed. Our results indicated pollen composition was largely influenced by floristic local biodiversity, plant phenology, and the presence of alien flowering species. Therefore, pollen molecular characterization based on DNA barcoding might serve useful to beekeepers in obtaining honeybee products with specific nutritional or therapeutic characteristics desired by food market demands.

  17. A statistical mixture model for estimating the proportion of unreduced pollen grains in perennial ryegrass (Lolium perenne L.) via the size of pollen grains

    NARCIS (Netherlands)

    Jansen, R.C.; Nijs, A.P.M. den

    1993-01-01

    The size of pollen grains is commonly used to indicate the ploidy level of pollen grains. In this paper observations of the diameter of pollen grains are evaluated from one diploid accession of perennial ryegrass (Lolium perenne L.), which was expected to produce diploid (unreduced) pollen grains in

  18. Direct Vinylation of Alcohols or Aldehydes Employing Alkynes as Vinyl Donors: A Ruthenium Catalyzed C-C Bond Forming Transfer Hydrogenation

    Science.gov (United States)

    Patman, Ryan L.; Chaulagain, Mani Raj; Williams, Vanessa M.; Krische, Michael J.

    2011-01-01

    Under the conditions of ruthenium catalyzed transfer hydrogenation, 2-butyne couples to benzylic and aliphatic alcohols 1a–1i to furnish allylic alcohols 2a–2i, constituting a direct C-H vinylation of alcohols employing alkynes as vinyl donors. Under related transfer hydrogenation conditions employing formic acid as terminal reductant, 2-butyne couples to aldehydes 4a, 4b, and 4e to furnish identical products of carbonyl vinylation 2a, 2b, and 2e. Thus, carbonyl vinylation is achieved from the alcohol or the aldehyde oxidation level in the absence of any stoichiometric metallic reagents. Nonsymmetric alkynes 6a–6c couple efficiently to aldehyde 4b to provide allylic alcohols 2m–2o as single regioisomers. Acetylenic aldehyde 7a engages in efficient intramolecular coupling to deliver cyclic allylic alcohol 8a. PMID:19173651

  19. Direct characterization of spin-transfer switching of nano-scale magnetic tunnel junctions using a conductive atomic force microscope

    International Nuclear Information System (INIS)

    Lee, Jia-Mou; Yang, Dong-Chin; Lee, Ching-Ming; Ye, Lin-Xiu; Chang, Yao-Jen; Wu, Te-ho; Lee, Yen-Chi; Wu, Jong-Ching

    2013-01-01

    We present an alternative method of spin-transfer-induced magnetization switching for magnetic tunnel junctions (MTJs) using a conductive atomic force microscope (CAFM) with pulsed current. The nominal MTJ cells' dimensions were 200 × 400 nm 2 . The AFM probes were coated with a Pt layer via sputtering to withstand up to several milliamperes. The pulsed current measurements, with pulse duration varying from 5 to 300 ms, revealed a magnetoresistance ratio of up to 120%, and an estimated intrinsic switching current density, based on the thermal activation model, of 3.94 MA cm −2 . This method demonstrates the potential skill to characterize nanometre-scale magnetic devices. (paper)

  20. From Allergens to Battery Anodes: Nature-Inspired, Pollen Derived Carbon Architectures for Room- and Elevated- Temperature Li-ion Storage

    Science.gov (United States)

    Tang, Jialiang; Pol, Vilas G.

    2016-02-01

    The conversion of allergic pollen grains into carbon microstructures was carried out through a facile, one-step, solid-state pyrolysis process in an inert atmosphere. The as-prepared carbonaceous particles were further air activated at 300 °C and then evaluated as lithium ion battery anodes at room (25 °C) and elevated (50 °C) temperatures. The distinct morphologies of bee pollens and cattail pollens are resembled on the final architecture of produced carbons. Scanning Electron Microscopy images shows that activated bee pollen carbon (ABP) is comprised of spiky, brain-like, and tiny spheres; while activated cattail pollen carbon (ACP) resembles deflated spheres. Structural analysis through X-ray diffraction and Raman spectroscopy confirmed their amorphous nature. X-ray photoelectron spectroscopy analysis of ABP and ACP confirmed that both samples contain high levels of oxygen and small amount of nitrogen contents. At C/10 rate, ACP electrode delivered high specific lithium storage reversible capacities (590 mAh/g at 50 °C and 382 mAh/g at 25 °C) and also exhibited excellent high rate capabilities. Through electrochemical impedance spectroscopy studies, improved performance of ACP is attributed to its lower charge transfer resistance than ABP. Current studies demonstrate that morphologically distinct renewable pollens could produce carbon architectures for anode applications in energy storage devices.

  1. Contemporary pollen flow, characterization of the maternal ecological neighbourhood and mating patterns in wild cherry (Prunus avium L.).

    Science.gov (United States)

    Cottrell, J E; Vaughan, S P; Connolly, T; Sing, L; Moodley, D J; Russell, K

    2009-08-01

    Conversion of lowland woodland to agricultural land and resulting fragmentation in Britain has been ongoing since Neolithic times. To counteract this decline, plantations of native species, often based on non-British planting stock, have been established. This may ultimately be detrimental to the integrity of the native gene pool. We explore the genetic and ecological factors influencing the success of components of the local pollen pool, including the effect of a non-native planting on an ancient woodland population of wild cherry. Wild cherry exhibits gametophytic self-incompatibility (GSI) and vegetative reproduction, both of which may be determinants of paternal success. The majority (61%) of the successful pollen originated from within the study site with a maximum pollen transfer distance of 694 m. There was a distinct departure from random mating, with over half the successful pollen originating from trees which occur within 100 m of the mother tree. Self-incompatibility, clonality, tree size and proximity to the mother tree were all found to influence paternal success. Kinship of pollen gametes within a maternal progeny was highest when a mother tree was surrounded by a large number of ramets of a single, compatible clone consisting of large, adult trees. Although the contribution from the non-native plantation is currently low, it is likely that this will increasingly contribute to the progeny of the adjacent ancient population as it matures. The results clearly show that in self-incompatible species, such as P. avium, close neighbours may be pollinated by very different components of the local pollen pool.

  2. Simple methods for in vitro pollen germination and pollen preservation of selected species of the genus Agave

    Directory of Open Access Journals (Sweden)

    Sigifredo López Díaz

    2008-01-01

    Full Text Available Simple methods to evaluate the viability and to preserve Agave tequilana Weber var. azul and A. angustifolia Haw pollen were established. Pollen viability was assessed by improving a growing media and evaluating three common pollen germination media components: sucrose, boric acid, and calcium ion. Optimal germination of pollen was obtained at 0.300 M sucrose, 0.324 mM boric acid, and 1.219 mM calcium nitrate and incubated at a temperature of 25°C. Agave pollen was preserved in olive oil and organic solvents. Olive oil, which is immiscible with water, provides an anhydrous environment and limits available oxygen, conditions similar to those provided by some organic solvents. Fresh pollen was put into eppendorf tubes containing n-butanol, n-propanol, isopropanol, extra virgin olive oil and preserved at -20, 4, and 25°C. The germination of the preserved pollen was scored at different time periods during preservation employing the optimal germination medium. The viability of pollen grains preserved at -20°C in olive oil, proved olive oil as an efficient medium for agave pollen preservation for at least 6 months.

  3. Quantifying pollen-vegetation relationships to reconstruct ancient forests using 19th-century forest composition and pollen data

    Science.gov (United States)

    Dawson, Andria; Paciorek, Christopher J.; McLachlan, Jason S.; Goring, Simon; Williams, John W.; Jackson, Stephen T.

    2016-01-01

    Mitigation of climate change and adaptation to its effects relies partly on how effectively land-atmosphere interactions can be quantified. Quantifying composition of past forest ecosystems can help understand processes governing forest dynamics in a changing world. Fossil pollen data provide information about past forest composition, but rigorous interpretation requires development of pollen-vegetation models (PVMs) that account for interspecific differences in pollen production and dispersal. Widespread and intensified land-use over the 19th and 20th centuries may have altered pollen-vegetation relationships. Here we use STEPPS, a Bayesian hierarchical spatial PVM, to estimate key process parameters and associated uncertainties in the pollen-vegetation relationship. We apply alternate dispersal kernels, and calibrate STEPPS using a newly developed Euro-American settlement-era calibration data set constructed from Public Land Survey data and fossil pollen samples matched to the settlement-era using expert elicitation. Models based on the inverse power-law dispersal kernel outperformed those based on the Gaussian dispersal kernel, indicating that pollen dispersal kernels are fat tailed. Pine and birch have the highest pollen productivities. Pollen productivity and dispersal estimates are generally consistent with previous understanding from modern data sets, although source area estimates are larger. Tests of model predictions demonstrate the ability of STEPPS to predict regional compositional patterns.

  4. Quantifying pollen-vegetation relationships to reconstruct ancient forests using 19th-century forest composition and pollen data

    Science.gov (United States)

    Dawson, Andria; Paciorek, Christopher J.; McLachlan, Jason S.; Goring, Simon; Williams, John W.; Jackson, Stephen T.

    2016-04-01

    Mitigation of climate change and adaptation to its effects relies partly on how effectively land-atmosphere interactions can be quantified. Quantifying composition of past forest ecosystems can help understand processes governing forest dynamics in a changing world. Fossil pollen data provide information about past forest composition, but rigorous interpretation requires development of pollen-vegetation models (PVMs) that account for interspecific differences in pollen production and dispersal. Widespread and intensified land-use over the 19th and 20th centuries may have altered pollen-vegetation relationships. Here we use STEPPS, a Bayesian hierarchical spatial PVM, to estimate key process parameters and associated uncertainties in the pollen-vegetation relationship. We apply alternate dispersal kernels, and calibrate STEPPS using a newly developed Euro-American settlement-era calibration data set constructed from Public Land Survey data and fossil pollen samples matched to the settlement-era using expert elicitation. Models based on the inverse power-law dispersal kernel outperformed those based on the Gaussian dispersal kernel, indicating that pollen dispersal kernels are fat tailed. Pine and birch have the highest pollen productivities. Pollen productivity and dispersal estimates are generally consistent with previous understanding from modern data sets, although source area estimates are larger. Tests of model predictions demonstrate the ability of STEPPS to predict regional compositional patterns.

  5. Pollen food allergy syndrome in Turkey: Clinical characteristics and evaluation of its association with skin test reactivity to pollens.

    Science.gov (United States)

    Özdemir, Seςil Kepil; Özgüςlü, Selcan

    2017-09-17

    There is limited data regarding pollen food allergy syndrome (PFAS) in Turkey. To investigate the clinical characteristics and possible risk factors of PFAS in Turkey, and to evaluate if there was an association between skin test reactivity to pollens and presence of PFAS. A total of 254 consecutive adult patients with pollen sensitivity were prospectively recruited. Patients were interviewed with a questionnaire including a list of pollen-associated foods. Patients were classified as having PFAS if they reported clear allergic symptoms compatible with PFAS. All participants underwent skin prick tests (SPT) to a panel of common aeroallergens, prick-to-prick tests with culprit fresh foods were performed in patients who gave consent. Self-reported PFAS was observed in 49 patients (19.3%). The most common culprit foods were kiwi, peach, tomato, melon and watermelon. Multiple logistic regression analysis showed that potential risk factors for PFAS were having asthma (OR=2.392, P=0.044) and tree pollen sensitization (OR=2.904, P=0.004). There were no significant differences in the SPT wheal sizes to individual pollen extracts between patients with and without PFAS with a positive SPT result for that pollen extract (P> 0.05). PFAS is frequent in pollen sensitized adults in Turkey. The most commonly implicated foods are kiwi, peach,tomato, melon and watermelon, in our geographical region. SPT wheal sizes to pollen extracts seems to be similar in patients with and without PFAS.

  6. The apical actin fringe contributes to localized cell wall deposition and polarized growth in the lily pollen tube.

    Science.gov (United States)

    Rounds, Caleb M; Hepler, Peter K; Winship, Lawrence J

    2014-09-01

    In lily (Lilium formosanum) pollen tubes, pectin, a major component of the cell wall, is delivered through regulated exocytosis. The targeted transport and secretion of the pectin-containing vesicles may be controlled by the cortical actin fringe at the pollen tube apex. Here, we address the role of the actin fringe using three different inhibitors of growth: brefeldin A, latrunculin B, and potassium cyanide. Brefeldin A blocks membrane trafficking and inhibits exocytosis in pollen tubes; it also leads to the degradation of the actin fringe and the formation of an aggregate of filamentous actin at the base of the clear zone. Latrunculin B, which depolymerizes filamentous actin, markedly slows growth but allows focused pectin deposition to continue. Of note, the locus of deposition shifts frequently and correlates with changes in the direction of growth. Finally, potassium cyanide, an electron transport chain inhibitor, briefly stops growth while causing the actin fringe to completely disappear. Pectin deposition continues but lacks focus, instead being delivered in a wide arc across the pollen tube tip. These data support a model in which the actin fringe contributes to the focused secretion of pectin to the apical cell wall and, thus, to the polarized growth of the pollen tube. © 2014 American Society of Plant Biologists. All Rights Reserved.

  7. Inbreeding and oubreeding effects on pollen fitness and zygote survival in Silene nutans (Caryophyllaceae)

    DEFF Research Database (Denmark)

    Hauser, Thure Pavlo; Siegismund, H.R.

    2000-01-01

    inbreeding depression, oubreeding effects, outcrossing, pollen fitness, selfing, Silene nutans, zygote survival......inbreeding depression, oubreeding effects, outcrossing, pollen fitness, selfing, Silene nutans, zygote survival...

  8. Energy flow analysis of amputee walking shows a proximally-directed transfer of energy in intact limbs, compared to a distally-directed transfer in prosthetic limbs at push-off.

    Science.gov (United States)

    Weinert-Aplin, R A; Howard, D; Twiste, M; Jarvis, H L; Bennett, A N; Baker, R J

    2017-01-01

    Reduced capacity and increased metabolic cost of walking occurs in amputees, despite advances in prosthetic componentry. Joint powers can quantify deficiencies in prosthetic gait, but do not reveal how energy is exchanged between limb segments. This study aimed to quantify these energy exchanges during amputee walking. Optical motion and forceplate data collected during walking at a self-selected speed for cohorts of 10 controls, 10 unilateral trans-tibial, 10 unilateral trans-femoral and 10 bilateral trans-femoral amputees were used to determine the energy exchanges between lower limb segments. At push-off, consistent thigh and shank segment powers were observed between amputee groups (1.12W/kg vs. 1.05W/kg for intact limbs and 0.97W/kg vs. 0.99W/kg for prosthetic limbs), and reduced prosthetic ankle power, particularly in trans-femoral amputees (3.12W/kg vs. 0.87W/kg). Proximally-directed energy exchange was observed in the intact limbs of amputees and controls, while prosthetic limbs displayed distally-directed energy exchanges at the knee and hip. This study used energy flow analysis to show a reversal in the direction in which energy is exchanged between prosthetic limb segments at push-off. This reversal was required to provide sufficient energy t