136 research outputs found

    Composition of Arthropod Species Assemblages in Bt-expressing and Near Isogenic Eggplants in Experimental Fields

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    The environmental impact of genetically modified (GM) plants in experimental fields has been examined in several ways, in particular with respect to the dynamics of specific nontarget organisms. The approach of sampling for biodiversity in agroecosystems to compare complex patterns could also be useful in studying potential disruptions caused by GM crops. In this study, we set up replicated field plots of Bt-expressing eggplants and near isogenic untransformed eggplants as a control. We monitored the presence and abundance of herbivore and predator arthropods in weekly visual samplings of the plant canopy for three growing seasons (2001-2003). Insect species were pooled in organismal taxonomic units (OTUs); three multivariate methods were used to compare species assemblage as an estimate of insect biodiversity. This multistep statistical approach proved to be efficient in recognizing association patterns, as evidenced by the data for the target species Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae) clearly showing a significant association with the control plots. All the analyses indicate a comparable species assemblage between transgenic and near isogenic eggplant areas. Our results suggest that some taxa may warrant more specific study. For example, Alticinae beetles (Coleoptera: Chrysomelidae) were alternatively more abundant in either of the two treatments, and their overall abundance was significantly higher on transgenic eggplants. In light of these results and because of their taxonomic proximity to the target species, these herbivores may represent an important nontarget group to be further studied. Moreover, some sap feeders (e.g., Homoptera: Cicadellidae) were more abundant on Bt-expressing plants in some samples in all 3 y

    Sufficient blood, safe blood: can we have both?

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    The decision in September 2011 in the UK to accept blood donations from non-practicing men who have sex with men (MSM) has received significant public attention. Will this rule change substantially boost the number of blood donations or will it make our blood less safe? Clearly, most European countries have a blood procurement problem. Fewer young people are donating, while the population is aging and more invasive therapies are requiring more blood. Yet if that was the reason for allowing non-practicing MSM to donate, clearly re-admission of some other, much larger populations that are currently deferred from donation should likewise be considered. As far as risks for blood safety are concerned, evidence has been provided that the current quality of infectious disease marker testing significantly mitigates against, although does not completely eradicate, risks associated with admission of donors with a high risk of carrying certain blood-transmissible agents. However, it could be argued that more effective recruitment of the non-donor pool, which is substantially larger than the group of currently ineligible donors, would be a better strategy. Recruitment of this group will benefit the availability of blood without jeopardizing the current excellent safety profile of blood

    Artificial Modulation of the Gating Behavior of a K+ Channel in a KvAP-DNA Chimera

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    We present experiments where the gating behavior of a voltage-gated ion channel is modulated by artificial ligand binding. We construct a channel-DNA chimera with the KvAP potassium channel reconstituted in an artificial membrane. The channel is functional and the single channel ion conductivity unperturbed by the presence of the DNA. However, the channel opening probability vs. bias voltage, i.e., the gating, can be shifted considerably by the electrostatic force between the charges on the DNA and the voltage sensing domain of the protein. Different hybridization states of the chimera DNA thus lead to different response curves of the channel

    Engineering Bispecificity into a Single Albumin-Binding Domain

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    Bispecific antibodies as well as non-immunoglobulin based bispecific affinity proteins are considered to have a very high potential in future biotherapeutic applications. In this study, we report on a novel approach for generation of extremely small bispecific proteins comprised of only a single structural domain. Binding to tumor necrosis factor-α (TNF-α) was engineered into an albumin-binding domain while still retaining the original affinity for albumin, resulting in a bispecific protein composed of merely 46 amino acids. By diversification of the non albumin-binding side of the three-helix bundle domain, followed by display of the resulting library on phage particles, bispecific single-domain proteins were isolated using selections with TNF-α as target. Moreover, based on the obtained sequences from the phage selection, a second-generation library was designed in order to further increase the affinity of the bispecific candidates. Staphylococcal surface display was employed for the affinity maturation, enabling efficient isolation of improved binders as well as multiparameter-based sortings with both TNF-α and albumin as targets in the same selection cycle. Isolated variants were sequenced and the binding to albumin and TNF-α was analyzed. This analysis revealed an affinity for TNF-α below 5 nM for the strongest binders. From the multiparameter sorting that simultaneously targeted TNF-α and albumin, several bispecific candidates were isolated with high affinity to both antigens, suggesting that cell display in combination with fluorescence activated cell sorting is a suitable technology for engineering of bispecificity. To our knowledge, the new binders represent the smallest engineered bispecific proteins reported so far. Possibilities and challenges as well as potential future applications of this novel strategy are discussed

    The use of health-related quality of life (HRQOL) in children and adolescents as an outcome criterion to evaluate family oriented support for young carers in Germany: an integrative review of the literature

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    <p>Abstract</p> <p>Background</p> <p>Young people below the age of 18, whose lives are affected by looking after a relative with a disability or long-term illness, are called young carers. Evidence based family oriented support for young carers and their families in Germany is currently being developed. To allow for scientific evaluation, an outcome criterion needs to be chosen. Until today, there are no assessment instruments available, which focus on young carer's specific demands and needs. As HRQOL seems to be an adequate alternative outcome criterion, an integrative review of the literature was carried out to verify this assumption.</p> <p>Methods</p> <p>The aim of the integrative review was to get information about a) the concept and the common definition of HRQOL in children, b) preferable HRQOL assessment techniques in children, and c) the relevance of HRQOL measures for the population of young carers. An additional aim of the review was to give advice on which instrument fits best to assess young carer's HRQOL in Germany. Searches were conducted in PubMed in order to obtain papers reporting about a) the development or psychometric assessment of instruments measuring HRQOL in children and adolescents up to the age of 18, and b) on the conceptual framework of HRQOL in children.</p> <p>Results</p> <p>HRQOL is a multidimensional construct covering physical, emotional, mental, social, and behavioural components of well-being and functioning as subjective perceived by a person depending on the cultural context and value system one is living in. Young carer's problems and needs are well covered by these common domains of HRQOL. Since no specific HRQOL-measures are available to address young carers, a generic one has to be chosen which a) has been created for use in children, b) allows self- and proxy-report, and c) has good psychometric testing results. Comparing four generic measures with currently best published psychometric testing results, items of the KIDSCREEN cover young carer's specific problems most accurate.</p> <p>Conclusion</p> <p>The KIDSCREEN questionnaires seems adequate to evaluate the intervention as their items cover young carer's needs and problems most accurate.</p

    Leading-order determination of the gluon polarisation from semi-inclusive deep inelastic scattering data

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    Using a novel analysis technique, the gluon polarisation in the nucleon is re-evaluated using the longitudinal double-spin asymmetry measured in the cross section of semi-inclusive single-hadron muoproduction with photon virtuality Q2>1 (GeV/c)2Q^2>1~({\rm GeV}/c)^2. The data were obtained by the COMPASS experiment at CERN using a 160 GeV/cc polarised muon beam impinging on a polarised 6^6LiD target. By analysing the full range in hadron transverse momentum pTp_{\rm T}, the different pTp_{\rm T}-dependences of the underlying processes are separated using a neural-network approach. In the absence of pQCD calculations at next-to-leading order in the selected kinematic domain, the gluon polarisation Δg/g\Delta g/g is evaluated at leading order in pQCD at a hard scale of μ2=Q2=3(GeV/c)2\mu^2= \langle Q^2 \rangle = 3 ({\rm GeV}/c)^2. It is determined in three intervals of the nucleon momentum fraction carried by gluons, xgx_{\rm g}, covering the range 0.04 ⁣< ⁣xg ⁣< ⁣0.280.04 \!<\! x_{ \rm g}\! <\! 0.28~ and does not exhibit a significant dependence on xgx_{\rm g}. The average over the three intervals, Δg/g=0.113±0.038(stat.)±0.036(syst.)\langle \Delta g/g \rangle = 0.113 \pm 0.038_{\rm (stat.)}\pm 0.036_{\rm (syst.)} at xg0.10\langle x_{\rm g} \rangle \approx 0.10, suggests that the gluon polarisation is positive in the measured xgx_{\rm g} range.Comment: 14 pages, 6 figure

    Longitudinal double spin asymmetries in single hadron quasi-real photoproduction at high pTp_T

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    We measured the longitudinal double spin asymmetries ALLA_{LL} for single hadron muo-production off protons and deuterons at photon virtuality Q2Q^2 < 1(GeV/c\it c)2^2 for transverse hadron momenta pTp_T in the range 0.7 GeV/c\it c to 4 GeV/c\it c . They were determined using COMPASS data taken with a polarised muon beam of 160 GeV/c\it c or 200 GeV/c\it c impinging on polarised 6LiD\mathrm{{}^6LiD} or NH3\mathrm{NH_3} targets. The experimental asymmetries are compared to next-to-leading order pQCD calculations, and are sensitive to the gluon polarisation ΔG\Delta G inside the nucleon in the range of the nucleon momentum fraction carried by gluons 0.05<xg<0.20.05 < x_g < 0.2

    Interplay among transversity induced asymmetries in hadron leptoproduction

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    In the fragmentation of a transversely polarized quark several left-right asymmetries are possible for the hadrons in the jet. When only one unpolarized hadron is selected, it exhibits an azimuthal modulation known as Collins effect. When a pair of oppositely charged hadrons is observed, three asymmetries can be considered, a di-hadron asymmetry and two single hadron asymmetries. In lepton deep inelastic scattering on transversely polarized nucleons all these asymmetries are coupled with the transversity distribution. From the high statistics COMPASS data on oppositely charged hadron-pair production we have investigated for the first time the dependence of these three asymmetries on the difference of the azimuthal angles of the two hadrons. The similarity of transversity induced single and di-hadron asymmetries is discussed. A new analysis of the data allows to establish quantitative relationships among them, providing for the first time strong experimental indication that the underlying fragmentation mechanisms are all driven by a common physical process.Comment: 6 figure

    Interplay among transversity induced asymmetries in hadron leptoproduction

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    In the fragmentation of a transversely polarized quark several left-right asymmetries are possible for the hadrons in the jet. When only one unpolarized hadron is selected, it exhibits an azimuthal modulation known as Collins effect. When a pair of oppositely charged hadrons is observed, three asymmetries can be considered, a di-hadron asymmetry and two single hadron asymmetries. In lepton deep inelastic scattering on transversely polarized nucleons all these asymmetries are coupled with the transversity distribution. From the high statistics COMPASS data on oppositely charged hadron-pair production we have investigated for the first time the dependence of these three asymmetries on the difference of the azimuthal angles of the two hadrons. The similarity of transversity induced single and di-hadron asymmetries is discussed. A new analysis of the data allows to establish quantitative relationships among them, providing for the first time strong experimental indication that the underlying fragmentation mechanisms are all driven by a common physical process.Comment: 6 figure
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