23,422 research outputs found

    Variation in sequence and location of the fumonisin mycotoxin niosynthetic gene cluster in Fusarium

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    In Fusarium, the ability to produce fumonisins is governed by a 17-gene fumonisin biosynthetic gene (FUM) cluster. Here, we examined the cluster in F. oxysporum strain O-1890 and nine other species selected to represent a wide range of the genetic diversity within the GFSC

    Evidence of environmental strains on charge injection in silole based organic light emitting diodes

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    Using d. functional theory (DFT) computations, the authors demonstrated a substantial skeletal relaxation when the structure of 2,5-bis-[4-anthracene-9-yl-phenyl]-1,1-dimethyl-3,4-diphenyl-silole (BAS) is optimized in the gas-phase comparing with the mol. structure detd. from monocrystal x-ray diffraction. The origin of such a relaxation is explained by a strong environmental strains induced by the presence of anthracene entities. Also, the estn. of the frontier orbital levels showed that this structural relaxation affects mainly the LUMO that is lowered of 190 meV in the gas phase. To check if these theor. findings would be confirmed for thin films of BAS, the authors turned to UV photoemission spectroscopy and/or inverse photoemission spectroscopy and electrooptical measurements. The study of the c.d. or voltage and luminance or voltage characteristics of an ITO/PEDOT/BAS/Au device clearly demonstrated a very unusual temp.-dependent behavior. Using a thermally assisted tunnel transfer model, this behavior likely originated from the variation of the electronic affinity of the silole deriv. with the temp. The thermal agitation relaxes the mol. strains in thin films as it is shown when passing from the cryst. to the gas phase. The relaxation of the intramol. thus induces an increase of the electronic affinity and, as a consequence, the more efficient electron injection in org. light-emitting diodes

    Magnetic excitations in the low-temperature ferroelectric phase of multiferroic YMn2O5 using inelastic neutron scattering

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    We studied magnetic excitations in a low-temperature ferroelectric phase of the multiferroic YMn2O5 using inelastic neutron scattering (INS). We identify low-energy magnon modes and establish a correspondence between the magnon peaks observed by INS and electromagnon peaks observed in optical absorption [1]. Furthermore, we explain the microscopic mechanism, which results in the lowest-energy electromagnon peak, by comparing the inelastic neutron spectral weight with the polarization in the commensurate ferroelectric phase.Comment: 4 pages, 4 figure

    No negative impact of Palliative sedation on relatives' experience of the dying phase and their wellbeing after the patient's death: An observational study

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    Background: Palliative sedation is the widely-used intervention of administering sedating agents to induce a state of unconsciousness to take away a dying patient's perception of otherwise irrelievable symptoms. However, it remains questionable whether this ethically complex intervention is beneficial for patients and whether the associated lack of communication in the last phase of life has a negative impact on relatives' wellbeing. Methods: An observational questionnaire study was conducted among relatives of a consecutive sample of patients who died a non-sudden death in the Erasmus MC Cancer Institute or in the hospice 'Laurens Cadenza' (both in Rotterdam) between 2010 and 2013. Results: Relatives filled in questionnaires regarding 151 patients who had been sedated and 90 patients who had not been sedated. The median time since all patients had passed away was 21 (IQR 14-32) months. No significant differences were found in relatives' assessments of the quality of end-of-life care, patients' quality of life in the last week before death and their quality of dying, between patients who did and did not receive sedation, or in relatives' satisfaction with their own life, their general health and their mental wellbeing after the patient's death. Conclusions: The use of sedation in these patients appears to have no negative effect on bereaved relatives' evaluation of the patient's dying phase, or on their own wellbeing after the patient's death

    Superfluid-insulator transition of the Josephson junction array model with commensurate frustration

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    We have studied the rationally frustrated Josephson-junction array model in the square lattice through Monte Carlo simulations of (2+1)(2+1)D XY-model. For frustration f=1/4f=1/4, the model at zero temperature shows a continuous superfluid-insulator transition. From the measurement of the correlation function and the superfluid stiffness, we obtain the dynamical critical exponent z=1.0z=1.0 and the correlation length critical exponent ν=0.4±0.05\nu=0.4 \pm 0.05. While the dynamical critical exponent is the same as that for cases f=0f=0, 1/2, and 1/3, the correlation length critical exponent is surprisingly quite different. When f=1/5f=1/5, we have the nature of a first-order transition.Comment: RevTex 4, to appear in PR

    Heavy Carriers and Non-Drude Optical Conductivity in MnSi

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    Optical properties of the weakly helimagnetic metal MnSi have been determined in the photon energy range from 2 meV to 4.5 eV using the combination of grazing incidence reflectance at 80 degrees (2 meV to 0.8 eV) and ellipsometry (0.8 to 4.5 eV). As the sample is cooled below 100 K the effective mass becomes strongly frequency dependent at low frequencies, while the scattering rate developes a linear frequency dependence. The complex optical conductivity can be described by the phenomenological relation \sigma(\omega,T) \propto (\Gamma(T)+i\omega)^{-1/2} used for cuprates and ruthenates.Comment: 5 pages, ReVTeX 4, 5 figures in eps forma

    Robust Humoral and Cellular Immune Responses to Pertussis in Adults After a First Acellular Booster Vaccination

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    IntroductionTo reduce the pertussis disease burden, nowadays several countries recommend acellular pertussis (aP) booster vaccinations for adults. We aimed to evaluate the immunogenicity of a first adult aP booster vaccination at childbearing age.MethodsIn 2014, healthy adults aged 25–29 years (n = 105), vaccinated during infancy with four doses of whole-cell pertussis (wP) vaccine, received a Tdap (tetanus, diphtheria, and aP) booster vaccination. Blood samples were collected longitudinally pre-booster, 2 and 4 weeks, and 1 year and 2 years post-booster. Tdap vaccine antigen-specific antibody levels and memory B- and T-cell responses were determined at all time points. Antibody persistence was calculated using a bi-exponential decay model.ResultsUpon booster vaccination, the IgG levels specific to all Tdap vaccine antigens were significantly increased. After an initial rapid decline in the first year, PT-IgG antibody decay was limited (15%) in the second year post-booster. The duration of a median level of PT-IgG ≥20 IU/mL was estimated to be approximately 9 years. Vaccine antigen-specific memory B- and T-cell numbers increased and remained at high levels although a significant decline was observed after 4 weeks post-booster. However, Th1, Th2, and Th17 cytokine production remained above pre-booster levels for 2 years.ConclusionThe Tdap booster vaccination in wP-primed Dutch adults induced robust long-term humoral and cellular immune responses to pertussis antigens. Furthermore, PT-IgG levels are predicted to remain above the presumed protective cut-off for at least 9 years which might deserves further attention in evaluating the current recommendation to revaccinate women during every new pregnancy

    Synthesis, spectroscopic, structural and thermal characterizations of [(C7H6NO4)2TeBr6·4H2O]

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    AbstractTellurium (IV) complexes with pyridine-2,6-dicarboxylate ligand were synthesized by slow evaporation from aqueous solutions yielding a new compound: [(C7H6NO4)2TeBr6·4H2O]. The structure of this compound was solved and refined by single-crystal X-ray diffraction. The compound is centrosymmetric P21/c (N°: 14) with the parameters a=8.875(5)Å, b=15.174(5)Å, c=10.199(5)Å, β=94.271° (5) and Z=2. The structure consists of isolated H2O, isolated [TeBr6]2− octahedral anions and (pyridine-2,6-dicarboxylate) [C7H6NO4]+ cations. The stability of the structure was ensured by ionic and hydrogen bonding contacts (N–H⋯Br and O–H⋯Br) and Van-Der Walls interaction. The thermal decomposition of the compound was studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The FTIR and Raman spectroscopy at different temperatures confirm the existence of vibrational modes that correspond to the organic, inorganic and water molecular groups. Additionally, the UV–Vis diffuse reflectance spectrum was recorded in order to investigate the band gap nature. The measurements show that this compound exhibits a semiconducting behavior with an optical band gap of 2.66eV

    Enhanced Bordetella pertussisacquisition rate in adolescents during the 2012 epidemic in the Netherlands and evidence for prolonged antibody persistence after infection.

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    IntroductionIn 2012 a large epidemic of pertussis occurred in the Netherlands. We assessed pertussis toxin (PT) antibody levels in longitudinal serum samples from Dutch 10-18 year-olds, encompassing the epidemic, to investigate pertussis infection incidence.Methods: Blood was sampled in October 2011 (n = 239 adolescents), then 1 year (2012; n = 228) and 3 years (2014; n = 167) later. PT-IgG concentrations were measured by immunoassay and concentrations ≥50 IU/mL (seropositive) assumed indicative of an infection within the preceding year.Results: During the 2012 epidemic, 10% of participants became seropositive, while this was just 3% after the epidemic. The pertussis acquisition rate proved to be sixfold higher during the epidemic (97 per 1,000 person-years) compared with 2012-2014 (16 per 1,000 person-years). In 2012, pertussis notifications among adolescents nationwide were 228/100,000 (0.23%), which is at least 40 times lower than the seropositivity percentage. Remarkably, 17 of the 22 seropositive participants in 2011, were still seropositive in 2012 and nine remained seropositive for at least 3 years.Discussion: Longitudinal studies allow a better estimation of pertussis infections in the population. A PT-IgG concentration ≥50 IU/mL as indication of recent infection may overestimate these numbers in cross-sectional serosurveillance and should be used carefully
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