3,079 research outputs found

    A study on mechanical properties of natural gas pipe material in high pressure hydrogen gas environment

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    Geometric quenching of orbital pair breaking in a single crystalline superconducting nanomesh network

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    In a superconductor Cooper pairs condense into a single state and in so doing support dissipation free charge flow and perfect diamagnetism. In a magnetic field the minimum kinetic energy of the Cooper pairs increases, producing an orbital pair breaking effect. We show that it is possible to significantly quench the orbital pair breaking effect for both parallel and perpendicular magnetic fields in a thin film superconductor with lateral nanostructure on a length scale smaller than the magnetic length. By growing an ultra-thin (2 nm thick) single crystalline Pb nanowire network, we establish nm scale lateral structure without introducing weak links. Our network suppresses orbital pair breaking for both perpendicular and in-plane fields with a negligible reduction in zero-field resistive critical temperatures. Our study opens a frontier in nanoscale superconductivity by providing a strategy for maintaining pairing in strong field environments in all directions with important technological implications

    Surface innovation for fabrication of superhydrophobic sand grains with improved water holding capacity for various environmental applications

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    The extreme evaporative loss of water from topsoil complicates cultivation in arid areas, and artificial plastic mulches that imitate sand mulches may minimize such water losses. However, the application of such plastic mulches is limited by their high cost and non-biodegradability. In this study, we developed superhydrophobic sand grains to reduce evaporative water loss from soil. Sea sand (SS) was coated with silica sol, which was prepared by the hydrolysis of tetraethoxysilane (TEOS) under alkaline conditions, followed by treatment with perfluorodecyltrichlorosilane (FDTS). A facile step was optimized for fabricating hydrophobic sand grains with contact angle of 151?? and rolling-off angle of 9.5?? to confirm the hydrophobicity and anti-droplet properties of the modified sand grains. The sands modified with engineered nanomaterials have shown the enhanced water holding and storage efficiency, and they can be applied as an oil sorbent scaffold to absorb oil (chloroform) from water selectively due to their water repelling properties. The coated superhydrophobic sand grains displayed anti-droplet and self-cleaning features, and withheld water for extended periods of time, which could benefit agriculture in arid regions and various environmental applications

    Prevalence of Human Papilloma Virus Infections and Cervical Cytological Abnormalities among Korean Women with Systemic Lupus Erythematosus

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    We performed a multicenter cross-sectional study of 134 sexually active systemic lupus erythematosus (SLE) patients to investigate the prevalence of and risk factors for high risk human papilloma virus (HPV) infection and cervical cytological abnormalities among Korean women with SLE. In this multicenter cross-sectional study, HPV testing and routine cervical cytologic examination was performed. HPV was typed using a hybrid method or the polymerase chain reaction. Data on 4,595 healthy women were used for comparison. SLE patients had greater prevalence of high-risk HPV infection (24.6% vs. 7.9%, P<0.001, odds ratio 3.8, 95% confidence interval 2.5-5.7) and of abnormal cervical cytology (16.4 vs. 2.8%, P<0.001, OR 4.4, 95% CI 2.5-7.8) compared with controls. SLE itself was identified as independent risk factors for high risk HPV infection among Korean women (OR 3.8, 95% CI 2.5-5.7) along with ≥2 sexual partners (OR 8.5, 95% CI 1.2-61.6), and Pap smear abnormalities (OR 97.3, 95% CI 6.5-1,456.7). High-risk HPV infection and cervical cytological abnormalities were more common among Korean women with SLE than controls. SLE itself may be a risk factor for HPV infection among Korean women, suggesting the importance of close monitoring of HPV infections and abnormal Pap smears in SLE patients

    Phosphorescent Sensor for Robust Quantification of Copper(II) Ion

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    A phosphorescent sensor based on a multichromophoric iridium(III) complex was synthesized and characterized. The construct exhibits concomitant changes in its phosphorescence intensity ratio and phosphorescence lifetime in response to copper(II) ion. The sensor, which is reversible and selective, is able to quantify copper(II) ions in aqueous media, and it detects intracellular copper ratiometrically.National Institute of General Medical Sciences (U.S.) ((Grant GM065519)Ewha Woman's University (Korea) (RP-Grant 2009

    How Well Does Societal Mobility Restriction Help Control the COVID-19 Pandemic? Evidence from Real-Time Evaluation

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    One of the most widely implemented policy response to the novel coronavirus (SARS-CoV-2) pandemic has been the imposition of restrictions on mobility (1). These restrictions have included both incentives, encouraging working from home, supported by a wide range of online activities such as meetings, lessons, and shopping, and sanctions, such as stay at home orders, restrictions on travel, and closure of shops, offices, and public transport (2-5). The measures constitute a major component of efforts to control the COVID-19 pandemic. Compared to previous epidemic responses, they are unprecedented in both scale and scope (6). The rationale underpinning these public health measures is that restricting normal activities decreases the number, duration, and proximity of interpersonal contacts and thus the potential for viral transmission. Transmission simulations using complex mathematical modelling have built on past experience such as the 1918 influenza epidemic (7), as well as assumptions about the contemporary scale and nature of contact in populations (8). However, the initial models were not always founded on empirical evidence from behavioral scientists on the feasibility or sustainability of mass social and behavior change in contemporary society. While reductions in interpersonal contact and increases in physical distancing are known to decrease respiratory infection spread (9), the paucity of recent examples of large-scale restrictions on mobility has limited the scope for research on their impact on transmission. Where restrictions have been imposed, as with Ebola, they have involved diseases with a different mode of transmission. Nonetheless, the rapidity of progression of this pandemic has forced many governments into trialing various approaches to containment with limited evidence of effectiveness (10). More conventional public health prevention measures (such as quarantine of contacts, isolation of infected individuals and contact tracing) and control measures in health systems (such as patient flow segregation, negative pressure ventilation, and use of personal protective equipment) (11-14), have been applied widely to control the epidemic in many countries as part of a portfolio of policy responses. However, mobility restriction as a new large-scale mass behavioral and social prescription has incurred considerable costs (15, 16). Estimates suggest global GDP growth has fallen by as much as 10% (17), at least in part due to mobility restriction policies. Although views differ, not least because of the lack of information of what would happen if the disease was unchecked and the emerging evidence of persisting disability in survivors, some have argued that this is greater than would be accounted for by the economic impact of direct illness and deaths from COVID-19 (18, 19). To inform decisions on large scale restrictions of mobility, there is an urgent need to assess their effectiveness in limiting pandemic spread. To this end, we examined the association of mobility with COVID-19 incidence in Organization of Economic Cooperation and Development (OECD) countries and equivalent economies such as Singapore and Taiwan

    Cold Nuclear Matter Effects on J/psi Yields as a Function of Rapidity and Nuclear Geometry in Deuteron-Gold Collisions at sqrt(s_NN) = 200 GeV

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    We present measurements of J/psi yields in d+Au collisions at sqrt(s_NN) = 200 GeV recorded by the PHENIX experiment and compare with yields in p+p collisions at the same energy per nucleon-nucleon collision. The measurements cover a large kinematic range in J/psi rapidity (-2.2 < y < 2.4) with high statistical precision and are compared with two theoretical models: one with nuclear shadowing combined with final state breakup and one with coherent gluon saturation effects. To remove model dependent systematic uncertainties we also compare the data to a simple geometric model. We find that calculations where the nuclear modification is linear or exponential in the density weighted longitudinal thickness are difficult to reconcile with the forward rapidity data.Comment: 449 authors from 66 institutions, 6 pages, 3 figures. Submitted to Physical Review Letters. 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

    Upsilon (1S+2S+3S) production in d+Au and p+p collisions at sqrt(s_NN)=200 GeV and cold-nuclear matter effects

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    The three Upsilon states, Upsilon(1S+2S+3S), are measured in d+Au and p+p collisions at sqrt(s_NN)=200 GeV and rapidities 1.2<|y|<2.2 by the PHENIX experiment at the Relativistic Heavy-Ion Collider. Cross sections for the inclusive Upsilon(1S+2S+3S) production are obtained. The inclusive yields per binary collision for d+Au collisions relative to those in p+p collisions (R_dAu) are found to be 0.62 +/- 0.26 (stat) +/- 0.13 (syst) in the gold-going direction and 0.91 +/- 0.33 (stat) +/- 0.16 (syst) in the deuteron-going direction. The measured results are compared to a nuclear-shadowing model, EPS09 [JHEP 04, 065 (2009)], combined with a final-state breakup cross section, sigma_br, and compared to lower energy p+A results. We also compare the results to the PHENIX J/psi results [Phys. Rev. Lett. 107, 142301 (2011)]. The rapidity dependence of the observed Upsilon suppression is consistent with lower energy p+A measurements.Comment: 495 authors, 11 pages, 9 figures, 5 tables. Submitted to Phys. Rev. C. 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

    Measurements of elliptic and triangular flow in high-multiplicity 3^{3}He++Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV

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    We present the first measurement of elliptic (v2v_2) and triangular (v3v_3) flow in high-multiplicity 3^{3}He++Au collisions at sNN=200\sqrt{s_{_{NN}}}=200 GeV. Two-particle correlations, where the particles have a large separation in pseudorapidity, are compared in 3^{3}He++Au and in pp++pp collisions and indicate that collective effects dominate the second and third Fourier components for the correlations observed in the 3^{3}He++Au system. The collective behavior is quantified in terms of elliptic v2v_2 and triangular v3v_3 anisotropy coefficients measured with respect to their corresponding event planes. The v2v_2 values are comparable to those previously measured in dd++Au collisions at the same nucleon-nucleon center-of-mass energy. Comparison with various theoretical predictions are made, including to models where the hot spots created by the impact of the three 3^{3}He nucleons on the Au nucleus expand hydrodynamically to generate the triangular flow. The agreement of these models with data may indicate the formation of low-viscosity quark-gluon plasma even in these small collision systems.Comment: 630 authors, 9 pages, 4 figures, 2 tables. v2 is the version accepted for publication by Physical Review Letters. 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
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