1,632 research outputs found

    Template-free synthesis of hierarchical hollow V2O5 microspheres with highly stable lithium storage capacity

    Get PDF
    Hollow V2O5 microspheres were successfully synthesized by a solvothermal method and subsequent calcination. The rigid hollow V2O5 cathode prepared in isopropanol solvent exhibited excellent cycling performance and rate capability. Within a voltage window of 2.5 to 4 V, a maximum specific discharge capacity of 128 mA h g−1 was delivered at 1 A g−1. Even after 500 cycles, the capacity retention was 92.2%.published_or_final_versio

    Janus monolayers of transition metal dichalcogenides.

    Get PDF
    Structural symmetry-breaking plays a crucial role in determining the electronic band structures of two-dimensional materials. Tremendous efforts have been devoted to breaking the in-plane symmetry of graphene with electric fields on AB-stacked bilayers or stacked van der Waals heterostructures. In contrast, transition metal dichalcogenide monolayers are semiconductors with intrinsic in-plane asymmetry, leading to direct electronic bandgaps, distinctive optical properties and great potential in optoelectronics. Apart from their in-plane inversion asymmetry, an additional degree of freedom allowing spin manipulation can be induced by breaking the out-of-plane mirror symmetry with external electric fields or, as theoretically proposed, with an asymmetric out-of-plane structural configuration. Here, we report a synthetic strategy to grow Janus monolayers of transition metal dichalcogenides breaking the out-of-plane structural symmetry. In particular, based on a MoS2 monolayer, we fully replace the top-layer S with Se atoms. We confirm the Janus structure of MoSSe directly by means of scanning transmission electron microscopy and energy-dependent X-ray photoelectron spectroscopy, and prove the existence of vertical dipoles by second harmonic generation and piezoresponse force microscopy measurements

    Hidden conformal symmetry of extreme and non-extreme Einstein-Maxwell-Dilaton-Axion black holes

    Full text link
    The hidden conformal symmetry of extreme and non-extreme Einstein-Maxwell-Dilaton-Axion (EMDA) black holes is addressed in this paper. For the non-extreme one, employing the wave equation of massless scalars, the conformal symmetry with left temperature TL=M2πaT_{L}=\frac{M}{2\pi a} and right temperature TR=M2a22πaT_{R}=\frac{\sqrt{M^{2}-a^{2}}}{2\pi a} in the near region is found. The conformal symmetry is spontaneously broken due to the periodicity of the azimuthal angle. The microscopic entropy is derived by the Cardy formula and is fully in consistence with the Bekenstein-Hawking area-entropy law. The absorption cross section in the near region is calculated and exactly equals that in a 2D CFT. For the extreme case, by redefining the conformal coordinates, the duality between the solution space and CFT is studied. The microscopic entropy is found to exactly agree with the area-entropy law.Comment: V3, typos corrected, version to appear in JHE

    Prenatal and Postnatal Tobacco Exposure and Behavioral Problems in 10-Year-Old Children: Results from the GINI-plus Prospective Birth Cohort Study

    Get PDF
    BACKGROUND: Prenatal and postnatal tobacco exposure have been reported to be associated with behavioral problems. However, the magnitude of the association with tobacco exposure at specific periods of exposure is unclear. OBJECTIVE: We assessed the relative risk of behavioral problems in children who had been exposed to tobacco smoke in utero and postnatally. METHODS: We analyzed data from a prospective birth cohort study in two cities in Germany: the German Infant Nutrition Intervention. Our sample included 5,991 children born between 1995 and 1998 as well as their parents. We measured behavioral problems using the Strength and Difficulties Questionnaire (SDQ) at follow-up 10 years after birth. According to prespecified SDQ cutoff values, children were classified as "normal," "borderline," or "abnormal" according to the subscales "emotional symptoms," "conduct problems," "hyperactivity/inattention," "peer-relationship problems," and a total difficulties score. Smoke exposure and further covariates were assessed using parent questionnaires. RESULTS: Compared with children not exposed to tobacco smoke, children exposed both pre- and postnatally to tobacco smoke had twice the estimated risk [95% confidence interval (CI), 1.4-3.1] of being classified as abnormal according to the total difficulties score of the SDQ at 10 years of age. Children who were only prenatally exposed had a 90% higher relative risk (95% CI, 0.9-4.0), whereas children who were only postnatally exposed had a 30% higher relative risk (95% CI, 0.9-1.9). These results could not be explained by confounding by parental education, father's employment, child's time spent in front of computer or television screen, being a single father or mother, or mother's age. CONCLUSIONS: Prenatal exposure to tobacco smoke is associated with behavioral problems in school-age children. Although our findings do not preclude the influence of postnatal exposure, prenatal exposure seems to be more important

    An ongoing process: A qualitative study of how the alcohol-dependent free themselves of addiction through progressive abstinence

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Most people being treated for alcoholism are unable to successfully quit drinking within their treatment programs. In few cases do we know the full picture of how abstinence is achieved in Taiwan. We tracked processes of abstinence in alcohol-dependency disorders, based on study evidence and results. This research explores the process of recovery from the viewpoint of the alcohol-dependent.</p> <p>Methods</p> <p>Semi-structured interviews were conducted in two different settings, using purpose sampling, during 2003-2004. The data were analyzed using content analysis. Participants were 32 adults, purposefully selected from an Alcoholics Anonymous group and a psychiatric hospital in North Taiwan.</p> <p>Results</p> <p>We found that the abstinence process is an ongoing process, in which the alcohol-dependent free themselves of addiction progressively. This process never ends or resolves in complete recovery. We have identified three stages in the struggle against alcoholism: the Indulgence, Ambivalence and Attempt (IAA) cycle, in which the sufferer is trapped in a cycle of attempting to give up and failing; the Turning Point, in which a Personal Nadir is reached, and the Ongoing Process of abstinence, in which a constant effort is made to remain sober through willpower and with the help of support groups. We also discuss Influencing Factors that can derail abstinence attempts, pushing the sufferer back into the IAA cycle.</p> <p>Conclusion</p> <p>This study provides important points of reference for alcohol and drug service workers and community healthcare professionals in Taiwan, casting light on the abstinence process and providing a basis for intervention or rehabilitation services.</p

    A clinical evaluation of amlexanox oral adhesive pellicles in the treatment of recurrent aphthous stomatitis and comparison with amlexanox oral tablets: a randomized, placebo controlled, blinded, multicenter clinical trial

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Amlexanox has been developed as a 5 percent topical oral paste for the treatment of patients with recurrent aphthous stomatitis (RAS) in most European countries. However, it is not yet available in China and has not been generally accepted in clinical treatment. The aim of this study was to explore the effectiveness of amlexanox oral adhesive pellicles in the treatment of minor recurrent aphthous ulcers, and compare the results with those of amlexanox oral adhesive tablets in order to analyse the difference between the two dosage forms of amlexanox.</p> <p>Methods</p> <p>We performed a randomized, blinded, placebo-controlled, parallel, multicenter clinical study. A total of 216 patients with minor recurrent aphthous ulcers (MiRAU) were recruited and randomized to amlexanox pellicles or placebo pellicles. Pellicles were consecutively applied four times per day, for five days. The size and pain level of ulcers were measured and recorded on treatment days 0, 4 and 6. Finally, the results were compared with those of our previous 104 cases treated with amlexanox tablets.</p> <p>Results</p> <p>Amlexanox oral adhesive pellicles significantly reduced ulcer size (P= 0.017 for day 4, P=0.038 for day 6) and alleviated ulcer pain (P=0.021 for day 4, P=0.036 for day 6). No significant difference was observed in the treatment effectiveness between the pellicle and tablet form of amlexanox.</p> <p>Conclusions</p> <p>Amlexanox oral adhesive pellicles are as effective and safe as amlexanox oral adhesive tablets in the treatment of MiRAU for this Chinese cohort. However, pellicles seem to be more comfortable to use when compared with the dosage form of tablets. Therefore, in clinical practice, amlexanox oral adhesive pellicles may be a better choice for RAS patients.</p> <p>Trials registration</p> <p>Nederlands Trial Register NTR1727.</p

    Effects of Combined Aspirin and Clopidogrel Therapy on Cardiovascular Outcomes: A Systematic Review and Meta-Analysis

    Get PDF
    BACKGROUND: Aspirin and clopidogrel monotherapies are effective treatments for preventing vascular disease. However, new evidence has emerged regarding the use of combined aspirin and clopidogrel therapy to prevent cardiovascular events. We therefore performed a comprehensive systematic review and meta-analysis to evaluate the benefits and harms of combined aspirin and clopidogrel therapy on major cardiovascular outcomes. METHODOLOGY/PRINCIPAL FINDINGS: We systematically searched Medline, Embase, the Cochrane Central Register of Controlled Trials, reference lists of articles, and proceedings of major meetings to identify studies to fit our analysis. Eligible studies were randomized controlled trials assessing the effect of combined aspirin and clopidogrel therapy compared with aspirin or clopidogrel monotherapy. We identified 7 trials providing data with a total of 48248 patients. These studies reported 5134 major cardiovascular events, 1626 myocardial infarctions, 1927 strokes, and 1147 major bleeding events. Overall, the addition of aspirin to clopidogrel therapy as compared to single drug therapy resulted in a 9% RR reduction (95%CI, 2 to 17) in major cardiovascular events, 14% RR reduction (95%CI, 3 to 24) in myocardial infarction, 16% RR reduction (95%CI, 1 to 28) in stroke, and 62% RR increase (95%CI, 26 to 108) in major bleeding events. We also present the data as ARR to explore net value as the reduction in cardiovascular events. Overall, we observed that combined therapy yielded 1.06% decrease (95%CI, 0.23% to 1.99%) in major cardiovascular events and 1.23% increase (95%CI, 0.52% to 2.14%) in major bleeding events. CONCLUSION/SIGNIFICANCE: Although the addition of aspirin to clopidogrel resulted in small relative reductions in major cardiovascular events, myocardial infarction, and stroke, it also resulted in a relative increase in major bleeding events. In absolute terms the benefits of combined therapy, a 1.06% reduction in major cardiovascular events, does not outweigh the harms, a 1.23% increase in major bleeding events

    Large-scale and rapid synthesis of disk-shaped and nano-sized graphene

    Get PDF
    We synthesized disk-shaped and nano-sized graphene (DSNG) though a novel ion-exchange methodology. This new methodology is achieved by constructing metal ion/ion-exchange resin framework. The morphology and size of the graphene can be modulated by changing the mass ratio of the carbon-containing resin to the cobalt-containing precursor. This is the first time to show that the DSNG formed on the granular transition metal substrate. The DSNG gives a high intensity of photoluminescence at near-UV wavelength of 311 nm which may provide a new type of fluorescence for applications in laser devices, ultraviolet detector UV-shielding agent and energy technology. The emission intensity of the DSNG is thirty times higher than that of the commercial large graphene. Our approach for graphene growth is conveniently controllable, easy to scale-up and the DSNG shows superior luminescent properties as compared to conventional large graphene
    corecore