Complete gate control of supercurrent in graphene p-n junctions

In a conventional Josephson junction of graphene, the supercurrent is not turned off even at the charge neutrality point, impeding further development of superconducting quantum information devices based on graphene. Here we fabricate bipolar Josephson junctions of graphene, in which a p-n potential barrier is formed in graphene with two closely spaced superconducting contacts, and realize supercurrent ON/OFF states using electrostatic gating only. The bipolar Josephson junctions of graphene also show fully gate-driven macroscopic quantum tunnelling behaviour of Josephson phase particles in a potential well, where the confinement energy is gate tuneable. We suggest that the supercurrent OFF state is mainly caused by a supercurrent dephasing mechanism due to a random pseudomagnetic field generated by ripples in graphene, in sharp contrast to other nanohybrid Josephson junctions. Our study may pave the way for the development of new gate-tuneable superconducting quantum information devices.open114344sciescopu

Preliminary effects and acceptability of a co-produced physical activity referral intervention

Objectives: To explore the preliminary effects and acceptability of a co-produced physical activity referral intervention. Study Design: Longitudinal design with data collected at baseline and post a 12-week physical activity referral intervention. Setting. Community leisure centre. Methods: 32 adults with controlled lifestyle-related health conditions took part in a physical activity referral intervention (co-produced by a multidisciplinary stakeholder group) comprising 12 weeks’ subsidised fitness centre access plus four behaviour change consultations. A complete case analysis (t-tests and magnitude-based inferences) was conducted to assess baseline-to-12-week change in physical activity, cardiometabolic, and psychological measures. Semi-structured interviews were conducted (n=12) to explore experiences of the intervention. Results: Mean improvements were observed in cardiorespiratory fitness-2 (3.6 ml.kg.-1min-1 (95% confidence interval 1.9 to 5.4) P<0.001) and moderate-to-vigorous physical activity (12.6 min.day (95% CI 4.3 to 29.6) P=0.013). Participants were positive about the support from exercise referral practitioners, but experienced some challenges in a busy and under staffed gym environment. Conclusions: A co-produced physical activity referral intervention elicited short-term improvements in physical activity and cardiometabolic health. Further refinements may be required, via ongoing feedback between stakeholders, researchers and service users, to achieve the intended holistic physical activity focus of the intervention, prior to a definitive trial

Wetting state on hydrophilic and hydrophobic micro-textured surfaces: Thermodynamic analysis and X-ray visualization

In this study, the wetting state on hydrophobic and hydrophilic micro-textured surfaces was investigated. High spatial resolution synchrotron X-ray radiography was used to overcome the limitations in visualization in previous research and clearly visualize the wetting state for each droplet under quantified surface conditions. Based on thermodynamic characteristics, a theoretical model for wetting state depending on the chemical composition (intrinsic contact angle) and geometrical morphology (roughness ratio) of the surfaces was developed. (C) 2015 AIP Publishing LLC.open1143sciescopu

Substance use and sexual behaviours of Japanese men who have sex with men: A nationwide internet survey conducted in Japan

BACKGROUND: Japanese men who have sex with men (MSM), especially those living in large metropolitan areas such as Tokyo and Osaka, are facing a growing HIV/AIDS epidemic. Although the Internet is used as a new venue for meeting sex partners, it can also serve as a useful research tool for investigating the risk behaviours of Japanese MSM. This Internet survey explored the extent of substance use and its association with sexual risk behaviours among Japanese MSM. METHODS: Between 28 February 2003 and 16 May 2003 MSM were recruited through 57 Japanese gay-oriented Web sites, gay magazines, and Internet mailing lists. Participants completed a structured questionnaire anonymously through the Internet. RESULTS: In total, 2,062 Japanese MSM completed the questionnaire. The average age of participants was 29.0 years and 70.5% identified as gay, 20.8% as bisexual, and 8.7% as other. Overall, 34.5% reported never using a substance, 45% reported ever using one type of substance (lifetime reported single substance users), and 19.6% had used more than 1 type of substance (lifetime reported multiple substance users) in their lifetimes. The substances most commonly used were amyl nitrite (63.2%), 5-methoxy-N, N-diisopropyltryptamine (5MEO-DIPT) (9.3%), and marijuana (5.7%). In the multivariate analysis, unprotected anal intercourse, having had 6 or more sexual partners, visiting a sex club/gay venue in the previous 6 months, a lower education level, and being 30 to 39 years of age were associated with both lifetime single and lifetime multiple substance use. Lifetime reported multiple substance use was also correlated with having a casual sex partner, having symptoms of depression, being diagnosed as HIV-positive, and greater HIV/AIDS-related knowledge. CONCLUSION: This is the first Internet-based research focused on the sexual and substance use behaviours of MSM in Asia. Our findings suggest a compelling need for prevention interventions to reduce HIV risk-related substance use behaviours among Japanese MSM. The results also suggest that the Internet is potentially a useful tool for collecting behavioural data and promoting prevention interventions among this population

Sourcing Technological Knowledge Through Foreign Inward Licensing to Boost the Performance of Indian Firms: The Contingent Effects of Internal R&D and Business Group Affiliation

Sourcing technological knowledge from abroad is becoming a popular strategy among emerging market firms (EMFs). Combining the Knowledge-Based View and the Resource Dependence Theory, we argue that augmenting technological knowledge through foreign licensing enables EMFs to access state-of-the-art technological knowledge, reduce operational costs and risks associated to the innovation process, and develop a knowledge-based competitive advantage, ultimately boosting their financial performance. Using data about Indian firms observed from 2001 to 2013, we find that firms with a higher share of foreign inward technology licenses report better financial performance. However, the positive impact of technological knowledge accessed through inward licensing on firm performance is contingent upon: (1) the internal knowledge developed through R&D activity, and (2) the affiliation with business groups. While Indian firms with higher level of internal R&D are able to better leverage the value of foreign technological knowledge, thus reaching higher performance, firms affiliated to business groups gain fewer benefits from licensed foreign technological knowledge than non-business-group affiliated firms

Tunneling properties of in-situ-fabricated intrinsic Josephson junctions in Bi2Sr2CaCu2O8+x single crystals

Slacks of intrinsic Josephson junctions were fabricated on the surface of Bi2Sr2CaCu2O8+x single crystals, using photolithography and Ar-ion etching. The number of junctions in a stack was controlled by the etching time, while the c-axis I-V and R versus T curves were measured in-situ in a vacuum chamber for T down to similar to 13 K. The tunneling resistance and the I-V curves are scaled by the surface junction resistance. The superconductivity of the surface conducting plane in contact with a Au electrode is weakened by the proximity to the normal metal. In a low-bias region, main tunneling properties of a junction are not affected by the presence of other junctions in a stack. (C) 2000 Elsevier Science B.V. All rights reserved.X11sciescopu

Progressive disappearance of the c-axis tunneling barrier in Bi2Sr2CaCu2O8+x single crystals near T-c

We observed an enhancement of the differential conductance dI/dV around the zero bias in junctions of Au/Bi2Sr2CaCu2O8+x(Bi2212) single crystals near the superconducting transition temperature of Bi2212 crystals with the tunneling current along the c axis. We attribute such an enhancement to an Andreev reflection (AR) between the surface Cu-O bilayer, which is in the normal state, and the next superconducting bilayer below the crystal surface. The continuous evolution from a gap-like depression to the AR peak structure of the dI/dV curves around the zero bias indicates weakening of the barrier strength of the non-superconducting layers between adjacent Cu-O bilayers as the temperature is raised up to T-c. We suggest that the fact can be conveniently used to investigate the possible existence of preformed pairs in the pseudogap state above T-c.X111sciescopuskciothe

Quasiparticle-pair interference effect in proximity-coupled junction ladders

We observed the quasiparticle-pair interference effect in arrays of Pb/Cu proximity-coupled junctions using de electrical conduction measurements. The effect caused a maximum in magnetoresistance at temperatures T greater than or equal to 3.70 K for integer values of filling factor f, and a beatlike pattern in the wide-field-range magnetoresistance, which is contrary to the usual behavior of Josephson-junction arrays. Numerical simulation on a single-plaquette array and a small-size ladder indicates that the prefactor of the interference cos phi term close to -1 best explains the results.open112sciescopu