2,617 research outputs found

    The relationship between transformational leadership and engagement : Self-efficacy as a mediator

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    The present study investigated whether followers’ self-efficacy mediates the relation-ship between a transformational leadership style and followers’ engagement. 307 Czech employees evaluated the transformational leadership of their superior and their own work-related self-efficacy and work engagement. Of the 4 compared structural equation models, the model in which self-efficacy partially mediates the relationship between transformational leadership and engagement fitted best. The relationship between trans-formational leadership and self-efficacy showed to be weak, whereas the relationship between self-efficacy and engagement appeared to be moderately strong. A mediation analysis reported weak indirect effect of transformational leadership on engagement through self-efficacy. However, direct effect of transformational leadership on engage-ment was strong. Self-efficacy explained only a small portion of the relationship be-tween transformational leadership and engagement. Current research findings expand theories explaining changes in engagement and the mechanism of how transformational leadership influences leadership outcomes.The present study investigated whether followers’ self-efficacy mediates the relation-ship between a transformational leadership style and followers’ engagement. 307 Czech employees evaluated the transformational leadership of their superior and their own work-related self-efficacy and work engagement. Of the 4 compared structural equation models, the model in which self-efficacy partially mediates the relationship between transformational leadership and engagement fitted best. The relationship between trans-formational leadership and self-efficacy showed to be weak, whereas the relationship between self-efficacy and engagement appeared to be moderately strong. A mediation analysis reported weak indirect effect of transformational leadership on engagement through self-efficacy. However, direct effect of transformational leadership on engage-ment was strong. Self-efficacy explained only a small portion of the relationship be-tween transformational leadership and engagement. Current research findings expand theories explaining changes in engagement and the mechanism of how transformational leadership influences leadership outcomes

    Efficient light-emitting diodes based on nanocrystalline perovskite in a dielectric polymer matrix.

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    Electroluminescence in light-emitting devices relies on the encounter and radiative recombination of electrons and holes in the emissive layer. In organometal halide perovskite light-emitting diodes, poor film formation creates electrical shunting paths, where injected charge carriers bypass the perovskite emitter, leading to a loss in electroluminescence yield. Here, we report a solution-processing method to block electrical shunts and thereby enhance electroluminescence quantum efficiency in perovskite devices. In this method, a blend of perovskite and a polyimide precursor dielectric (PIP) is solution-deposited to form perovskite nanocrystals in a thin-film matrix of PIP. The PIP forms a pinhole-free charge-blocking layer, while still allowing the embedded perovskite crystals to form electrical contact with the electron- and hole-injection layers. This modified structure reduces nonradiative current losses and improves quantum efficiency by 2 orders of magnitude, giving an external quantum efficiency of 1.2%. This simple technique provides an alternative route to circumvent film formation problems in perovskite optoelectronics and offers the possibility of flexible and high-performance light-emitting displays.The authors acknowledge funding from the Gates Cambridge Trust, the Singapore National Research Foundation (Energy Innovation Programme Office), the KACST-Cambridge University Joint Centre of Excellence, the Royal Society/Sino-British Fellowship Trust, and the Engineering and Physical Sciences Research Council, UK. We also thank Dr. Alessandro Sepe for helpful discussions of the XRD data.This is the final version of the article. It first appeared from ACS via http://dx.doi.org/10.1021/acs.nanolett.5b0023

    Multiphase Nanostructure of a Quinary Metal Oxide Electrocatalyst Reveals a New Direction for OER Electrocatalyst Design

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    Ce-rich mixed metal oxides comprise a recently discovered class of -electrocatalysts for the oxygen evolution reaction (OER). In particular, at current densities below 10 mA cm^(−2), Ni_(0.3)Fe_(0.07)Co_(0.2)Ce_(0.43)O_x exhibits ¬superior activity compared to the corresponding transition metal oxides, despite the relative inactivity of ceria. To elucidate the enhanced activity and underlying catalytic mechanism, detailed structural characterization of this quinary oxide electrocatalyst is reported. Transmission electron microscopy imaging of cross-section films as-prepared and after electrochemical testing reveals a stable two-phase nanostructure composed of 3–5 nm diameter crystallites of fluorite CeO_2 intimately mixed with 3–5 nm crystallites of transition metal oxides alloyed in the rock salt NiO structure. Dosing experiments demonstrate that an electron flux greater than ≈1000 e Å^(−2) s^(−1) causes the inherently crystalline material to become amorphous. A very low dose rate of 130 e Å^(−2) s^(−1) is employed for atomic resolution imaging using inline holography techniques to reveal a nanostructure in which the transition metal oxide nanocrystals form atomically sharp boundaries with the ceria nanocrystals, and these results are corroborated with extensive synchrotron X-ray absorption spectroscopy measurements. Ceria is a well-studied cocatalyst for other heterogeneous and electrochemical reactions, and our discovery introduces biphasic cocatalysis as a design concept for improved OER electrocatalysts

    Relative Efficacy of AS03-Adjuvanted Pandemic Influenza A(H1N1) Vaccine in Children: Results of a Controlled, Randomized Efficacy Trial

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    Background. the vaccine efficacy (VE) of 1 or 2 doses of AS03-adjuvanted influenza A(H1N1) vaccine relative to that of 2 doses of nonadjuvanted influenza A(H1N1) vaccine in children 6 months to <10 years of age in a multinational study conducted during 2010-2011.Methods. A total of 6145 children were randomly assigned at a ratio of 1: 1: 1 to receive 2 injections 21 days apart of A/California/7/2009(H1N1)-AS03 vaccine at dose 1 and saline placebo at dose 2, 2 doses 21 days apart of A/California/7/2009(H1N1)-AS03 vaccine (the Ad2 group), or 2 doses 21 days apart of nonadjuvanted A/California/7/2009(H1N1) vaccine (the NAd2 group). Active surveillance for influenza-like illnesses continued from days 14 to 385. Nose and throat samples obtained during influenza-like illnesses were tested for A/California/7/2009 (H1N1), using reverse-transcriptase polymerase chain reaction. Immunogenicity, reactogenicity, and safety were assessed.Results. There were 23 cases of confirmed 2009 pandemic influenza A(H1N1) (A[H1N1]pdm09) infection for the primary relative VE analysis. the VE in the Ad2 group relative to that in the NAd2 group was 76.8% (95% confidence interval, 18.5%-93.4%). the benefit of the AS03 adjuvant was demonstrated in terms of the greater immunogenicity observed in the Ad2 group, compared with the NAd2 group.Conclusion. the 4-8-fold antigen-sparing adjuvanted pandemic influenza vaccine demonstrated superior and clinically important prevention of A(H1N1)pdm09 infection, compared with nonadjuvanted vaccine, with no observed increase in medically attended or serious adverse events. These data support the use of adjuvanted influenza vaccines during influenza pandemics.GlaxoSmithKline BiologicalsUniv Melbourne, Murdoch Childrens Res Inst, Carlton, Vic 3010, AustraliaUniv Melbourne, Melbourne Sch Populat & Global Hlth, Carlton, Vic 3010, AustraliaGlaxoSmithKline Vaccines, King of Prussia, PA USANovavax, Rockville, MD USAMary Chiles Gen Hosp, Dept Pediat, Manila, PhilippinesDe La Salle Hlth Sci Inst, Dept Pediat, Dasmarinas City, PhilippinesRes Inst Trop Med, Dept Hlth, Muntinlupa, PhilippinesUniversidade Federal de São Paulo, Dept Pediat, São Paulo, BrazilFac Ciencias Med Santa Casa São Paulo, Dept Pediat, São Paulo, BrazilAssoc Fundo Incent Pesquisa, São Paulo, BrazilInst Costarricense Invest Clin, San Jose, Costa RicaNatl Inst Publ Hlth Mexico, Cuernavaca, Morelos, MexicoUniv Autonoma Nuevo Leon, Serv Med, Monterrey, MexicoInst Nacl Pediat Mexico, Mexico City, DF, MexicoHosp Gen Durango, Durango, MexicoPhramongkutklao Hosp, Infect Dis Unit, Dept Pediat, Bangkok, ThailandKhon Kaen Univ, Dept Pediat, Fac Med, Khon Kaen, ThailandNatl Healthcare Grp Polyclin, Singapore, SingaporeCtr Estudios Infect Pediat, Cali, ColombiaGlaxoSmithKline Vaccines, Wavre, BelgiumGlaxoSmithKline Vaccines, Rixensart, BelgiumUniversidade Federal de São Paulo, Dept Pediat, São Paulo, BrazilWeb of Scienc

    Formation of dense partonic matter in relativistic nucleus-nucleus collisions at RHIC: Experimental evaluation by the PHENIX collaboration

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    Extensive experimental data from high-energy nucleus-nucleus collisions were recorded using the PHENIX detector at the Relativistic Heavy Ion Collider (RHIC). The comprehensive set of measurements from the first three years of RHIC operation includes charged particle multiplicities, transverse energy, yield ratios and spectra of identified hadrons in a wide range of transverse momenta (p_T), elliptic flow, two-particle correlations, non-statistical fluctuations, and suppression of particle production at high p_T. The results are examined with an emphasis on implications for the formation of a new state of dense matter. We find that the state of matter created at RHIC cannot be described in terms of ordinary color neutral hadrons.Comment: 510 authors, 127 pages text, 56 figures, 1 tables, LaTeX. Submitted to Nuclear Physics A as a regular article; v3 has minor changes in response to referee comments. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    Induction of cell cycle arrest and apoptosis by copper complex Cu(SBCM)₂ towards oestrogen-receptor positive MCF-7 breast cancer cells

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    Copper complexes have the potential to be developed as targeted therapy for cancer because cancer cells take up larger amounts of copper than normal cells. Copper complex Cu(SBCM)2 has been reported to induce cell cycle arrest and apoptosis towards triple-negative breast cancer cells. Nevertheless, its effect towards other breast cancer subtypes has not been explored. Therefore, the present study was conducted to investigate the effect of Cu(SBCM)₂ towards oestrogen-receptor positive MCF-7 breast cancer cells. Growth inhibition of Cu(SBCM)₂ towards MCF-7 and human non-cancerous MCF-10A breast cells was determined by MTT assay. Morphological changes of Cu(SBCM)2-treated-MCF-7 cells were observed under an inverted microscope. Annexin V/PI apoptosis assay and cell cycle analysis were evaluated by flow cytometry. The expression of wild-type p53 protein was evaluated by Western blot analysis. The intracellular ROS levels of MCF-7 treated with Cu(SBCM)₂ were detected using DCFH-DA under a fluorescence microscope. The cells were then co-treated with Cu(SBCM)₂ and antioxidants to evaluate the involvement of ROS in the cytotoxicity of Cu(SBCM)2. Docking studies of Cu(SBCM)2 with DNA, DNA topoisomerase I, and human ribonucleotide reductase were also performed. The growth of MCF-7 cells was inhibited by Cu(SBCM)2 in a dose-dependent manner with less toxicity towards MCF-10A cells. It was found that Cu(SBCM)₂ induced G2/M cell cycle arrest and apoptosis in MCF-7 cells, possibly via a p53 pathway. Induction of intracellular ROS was not detected in MCF-7 cells. Interestingly, antioxidants enhance the cytotoxicity of Cu(SBCM)2 towards MCF-7 cells. DNA topoisomerase I may be the most likely target that accounts for the cytotoxicity of Cu(SBCM)₂

    Dopaminergic Polymorphisms Associated with Time-on-Task Declines and Fatigue in the Psychomotor Vigilance Test

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    Prolonged demands on the attention system can cause a decay in performance over time known as the time-on-task effect. The inter-subject differences in the rate of this decline are large, and recent efforts have been made to understand the biological bases of these individual differences. In this study, we investigate the genetic correlates of the time-on-task effect, as well as its accompanying changes in subjective fatigue and mood. N = 332 subjects performed a 20-minute test of sustained attention (the Psychomotor Vigilance Test) and rated their subjective states before and after the test. We observed substantial time-on-task effects on average, and large inter-individual differences in the rate of these declines. The 10-repeat allele of the variable number of tandem repeats marker (VNTR) in the dopamine transporter gene and the Met allele of the catechol-o-methyl transferase (COMT) Val158Met polymorphism were associated with greater vulnerability to time-on-task. Separately, the exon III DRD4 48 bp VNTR of the dopamine receptor gene DRD4 was associated with subjective decreases in energy. No polymorphisms were associated with task-induced changes in mood. We posit that the dopamine transporter and COMT genes exert their effects by increasing dopaminergic tone, which may induce long-term changes in the prefrontal cortex, an important mediator of sustained attention. Thus, these alleles may affect performance particularly when sustained dopamine release is necessary

    Inventory of Novel Animal Models Addressing Etiology of Preeclampsia in the Development of New Therapeutic/Intervention Opportunities.

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    Preeclampsia is a pregnancy-related disease afflicting 3-7% of pregnancies worldwide and leads to maternal and infant morbidity and mortality. The disease is of placental origin and is commonly described as a disease of two stages. A variety of preeclampsia animal models have been proposed, but all of them have limitations in fully recapitulating the human disease. Based on the research question at hand, different or multiple models might be suitable. Multiple animal models in combination with in vitro or ex vivo studies on human placenta together offer a synergistic platform to further our understanding of the etiology of preeclampsia and potential therapeutic interventions. The described animal models of preeclampsia divide into four categories (i) spontaneous, (ii) surgically induced, (iii) pharmacologically/substance induced, and (iv) transgenic. This review aims at providing an inventory of novel models addressing etiology of the disease and or therapeutic/intervention opportunities

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum
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