172 research outputs found

    On-site residence time in a driven diffusive system: violation and recovery of mean-field

    Full text link
    We investigate simple one-dimensional driven diffusive systems with open boundaries. We are interested in the average on-site residence time defined as the time a particle spends on a given site before moving on to the next site. Using mean-field theory, we obtain an analytical expression for the on-site residence times. By comparing the analytic predictions with numerics, we demonstrate that the mean-field significantly underestimates the residence time due to the neglect of time correlations in the local density of particles. The temporal correlations are particularly long-lived near the average shock position, where the density changes abruptly from low to high. By using Domain wall theory (DWT), we obtain highly accurate estimates of the residence time for different boundary conditions. We apply our analytical approach to residence times in a totally asymmetric exclusion process (TASEP), TASEP coupled to Langmuir kinetics (TASEP + LK), and TASEP coupled to mutually interactive LK (TASEP + MILK). The high accuracy of our predictions is verified by comparing these with detailed Monte Carlo simulations

    Metallic superhydrophobic surfaces via thermal sensitization

    Get PDF
    Superhydrophobic surfaces (i.e., surfaces extremely repellent to water) allow water droplets to bead up and easily roll off from the surface. While a few methods have been developed to fabricate metallic superhydrophobic surfaces, these methods typically involve expensive equipment, environmental hazards, or multi-step processes. In this work, we developed a universal, scalable, solvent-free, one-step methodology based on thermal sensitization to create appropriate surface texture and fabricate metallic superhydrophobic surfaces. To demonstrate the feasibility of our methodology and elucidate the underlying mechanism, we fabricated superhydrophobic surfaces using ferritic (430) and austenitic (316) stainless steels (representative alloys) with roll off angles as low as 4° and 7°, respectively. We envision that our approach will enable the fabrication of superhydrophobic metal alloys for a wide range of civilian and military applications

    Copper-enriched diamond-like carbon coatings promote regeneration at the bone�implant interface

    Get PDF
    There have been several attempts to design innovative biomaterials as surface coatings to enhance the biological performance of biomedical implants. The objective of this study was to design multifunctional Cu/a-C:H thin coating depositing on the Ti-6Al-4V alloy (TC4) via magnetron sputtering in the presence of Ar and CH4 for applications in bone implants. Moreover, the impact of Cu amount and sp2/sp3 ratio on the interior stress, corrosion behavior, mechanical properties, and tribological performance and biocompatibility of the resulting biomaterial was discussed. X-ray photoelectron spectroscopy (XPS) revealed that the sp2/sp3 portion of the coating was enhanced for samples having higher Cu contents. The intensity of the interior stress of the Cu/a-C:H thin bio-films decreased by increase of Cu content as well as the sp2/sp3 ratio. By contrast, the values of Young's modulus, the H3/E2 ratio, and hardness exhibited no significant difference with enhancing Cu content and sp2/sp3 ratio. However, there was an optimum Cu content (36.8 wt.) and sp2/sp3 ratio (4.7) that it is feasible to get Cu/a-C:H coating with higher hardness and tribological properties. Electrochemical impedance spectroscopy test results depicted significant improvement of Ti-6Al-4V alloy corrosion resistance by deposition of Cu/a-C:H thin coating at an optimum Ar/CH4 ratio. Furthermore, Cu/a-C:H thin coating with higher Cu contents showed better antibacterial properties and higher angiogenesis and osteogenesis activities. The coated samples inhibited the growth of bacteria as compared to the uncoated sample (p < 0.05). In addition, such coating composition can stimulate angiogenesis, osteogenesis and control host response, thereby increasing the success rate of implants. Moreover, Cu/a-C:H thin films encouraged development of blood vessels on the surface of titanium alloy when the density of grown blood vessels was increased with enhancing the Cu amount of the films. It is speculated that such coating can be a promising candidate for enhancing the osseointegration features. © 2020 Biomedical engineering; Materials science; Biomimetics; Tissue engineering; Coatings; Angiogenesis, Osteogenesis corrosion resistance; Copper; Hydrogenated amorphous carbon © 202

    Cervical cancer screening service utilisation in UK.

    Get PDF
    This study investigates empirically how past screening behaviour, individual and household characteristics affect the current uptake of cervical cancer screening in UK. For the conceptual framework, we use a modified Grossman model which is extended for non-economic factors. A dynamic version of a random effects panel probit model with initial conditions is estimated on the balanced sub-sample of the data. The analysis sample is restricted to women of age 16 and older and grouped into different age categories with respect to the NHS Cervical Screening Programme (NHSCSP). As dataset a balanced panel data of 857 women with 11,998 observations from the British Household Panel Study (BHPS) for the period from 1992 to 2008 is used for the analysis. Results suggest show that previous screening uptake, age, partner status, employment status and a previous GP visit have a significant influence on the likelihood of the uptake of cervical cancer screening

    National guidelines for cognitive assessment and rehabilitation of Iranian traumatic brain injury patients

    Get PDF
    Background: Individuals with moderate to severe traumatic brain injury (TBI) often have prolonged cognitive impairments, resulting in long-term problems with their real-life activities. Given the urgent need for evidence-based recommendations for neuropsychological management of Iranian TBI patients, the current work aimed to adapt eligible international guidelines for cognitive assessment and rehabilitation of the TBI patients in Iran. Methods: The project was led by an executive committee, under the supervision of the Iranian Ministry of Health and Medical Education (MOHME). Following a systematic literature search and selection process, four guidelines were included for adaptation. Clinical recommendations of the source guidelines were tabulated as possible clinical scenarios for 90 PICO clinical questions covering all relevant phases of care. After summing up the scenarios, our initial list of recommendations was drafted according to the Iranian patients� conditions. The final decision-making, with the contribution of a national interdisciplinary panel of 37 experts from across the country, was conducted in two rounds using online and offline survey forms (Round 1), and face-to-face and telephone meetings (Round 2). Results: A total of 63 recommendations in six sections were included in the final list of recommendations, among which 24 were considered as key recommendations. In addition, some of the recommendations were identified as fundamental, meaning that proper implementation of the other recommendations is largely dependent on their implementation. Conclusion: Iranian health policy makers and rehabilitation program managers are recommended to address some fundamental issues to provide the necessary infrastructure to set up an efficient cognitive rehabilitation service system. © 2020 Academy of Medical Sciences of I.R. Iran. All rights reserved
    corecore