1,763 research outputs found

    Probing polymer chain constraint and synergistic effects in nylon 6-clay nanocomposites and nylon 6-silica flake sub-micro composites with nanomechanics

    Get PDF
    In this study, we report that a synergistic effect exists in the surface mechanical properties of nylon 6–clay nanocomposites (NC) that can be shown by nanomechanical testing. The hardness, elastic modulus, and nanoindentation creep behavior of nylon 6 and its nanocomposites with different filler loading produced by melt compounding were contrasted to those of model nylon 6 sub-microcomposites (SMC) reinforced by sub-micro-thick silica flakes in which constraint cannot occur due to the difference in filler geometry. Polymer chain constraint was assessed by the analysis of nanoindentation creep data. Time-dependent creep decreased with increasing the filler loading in the NC consistent with the clay platelets exerting a constraint effect on the polymer chains which increases with filler loading. In contrast, there was no evidence of any reduced time-dependent creep for the SMC samples, consistent with a lack of constraint expected due to much lower aspect ratio of the silica flake

    The effect of electronic prescribing and medication administration on nurses’ workflow and activities: an uncontrolled before and after study

    Get PDF
    Background: Electronic prescribing and medication administration (ePMA) is purported to improve patient safety through a number of benefits including reducing medication errors and facilitating identification of prescribers. However little is known of its effect on nurses’ workflow and the associated patient safety implications. Our objective was to explore differences in drug round duration, medication administration workflow and activities, interruptions, and timeliness of medication administration before and after implementation of ePMA. / Methods: The study was an uncontrolled before and after study starting one month before and continuing until one month after implementation of ePMA, in a medicine for the elderly ward in a UK teaching hospital. Observation of nursing staff and documentation of workflow patterns, activities, interruptions and timeliness of medication administration during 20 scheduled drug rounds pre-ePMA and 14 rounds afterwards. / Results: While the introduction of ePMA did not significantly affect drug round duration, it altered the distribution of tasks with a doubling of the time spent on documentation. As might be expected, it eliminated time spent searching for paper drug charts. While there was no significant change in interruption rate, the types of interruption changed with an increase in healthcare related interruptions and a decrease in non-healthcare related interruptions. The timeliness of medication administration improved. / Conclusion: This small exploratory study suggests that introduction of ePMA does not significantly affect drug round duration, but alters the time spent on different tasks. The timeliness of medication administration improved, with potential benefits to patient safety

    A quality improvement project to increase self-administration of medicines in an acute hospital

    Get PDF
    Quality problem or issue A patient survey found significantly fewer patients reported they had self-administered their medicines while in hospital (20% of 100 patients) than reported that they would like to (44% of 100). We aimed to make self-administration more easily available to patients who wanted it. Initial assessment We conducted a failure, modes and effects analysis, collected baseline data on four wards and carried out observations. Choice of solution Our initial assessment suggested that the main areas we should focus on were raising patient awareness of self-administration, changing the patient assessment process and creating a storage solution for medicines being self-administered. We developed new patient information leaflets and posters and a doctor’s assessment form using Plan–Do–Study–Act cycles. We developed initial designs for a storage solution. Implementation We piloted the new materials on three wards; the fourth withdrew due to staff shortages. Evaluation Following collection of baseline data, we continued to collect weekly data. We found that the proportion of patients who wished to self-administer who reported that they were able to do so, significantly increased from 41% (of 155 patients) to 66% (of 118 patients) during the study, despite a period when the hospital was over capacity. Lessons learned Raising and maintaining healthcare professionals’ awareness of self-administration can greatly increase the proportion of patients who wish to self-administer who actually do so. Healthcare professionals prefer multi-disciplinary input into the assessment process

    SARS-CoV-2 anti-spike IgG antibody responses after second dose of ChAdOx1 or BNT162b2 and correlates of protection in the UK general population

    Get PDF
    Antibody responses are an important part of immunity after Coronavirus Disease 2019 (COVID-19) vaccination. However, antibody trajectories and the associated duration of protection after a second vaccine dose remain unclear. In this study, we investigated anti-spike IgG antibody responses and correlates of protection after second doses of ChAdOx1 or BNT162b2 vaccines for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the United Kingdom general population. In 222,493 individuals, we found significant boosting of anti-spike IgG by the second doses of both vaccines in all ages and using different dosing intervals, including the 3-week interval for BNT162b2. After second vaccination, BNT162b2 generated higher peak levels than ChAdOX1. Older individuals and males had lower peak levels with BNT162b2 but not ChAdOx1, whereas declines were similar across ages and sexes with ChAdOX1 or BNT162b2. Prior infection significantly increased antibody peak level and half-life with both vaccines. Anti-spike IgG levels were associated with protection from infection after vaccination and, to an even greater degree, after prior infection. At least 67% protection against infection was estimated to last for 2–3 months after two ChAdOx1 doses, for 5–8 months after two BNT162b2 doses in those without prior infection and for 1–2 years for those unvaccinated after natural infection. A third booster dose might be needed, prioritized to ChAdOx1 recipients and those more clinically vulnerable

    Nonthermal Emission from Star-Forming Galaxies

    Full text link
    The detections of high-energy gamma-ray emission from the nearby starburst galaxies M82 & NGC253, and other local group galaxies, broaden our knowledge of star-driven nonthermal processes and phenomena in non-AGN star-forming galaxies. We review basic aspects of the related processes and their modeling in starburst galaxies. Since these processes involve both energetic electrons and protons accelerated by SN shocks, their respective radiative yields can be used to explore the SN-particle-radiation connection. Specifically, the relation between SN activity, energetic particles, and their radiative yields, is assessed through respective measures of the particle energy density in several star-forming galaxies. The deduced energy densities range from O(0.1) eV/cm^3 in very quiet environments to O(100) eV/cm^3 in regions with very high star-formation rates.Comment: 17 pages, 5 figures, to be published in Astrophysics and Space Science Proceeding

    Low doses of caffeine reduce heart rate during submaximal cycle ergometry

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The purpose of this study was to examine the cardiovascular effects of two low-levels of caffeine ingestion in non habitual caffeine users at various submaximal and maximal exercise intensities.</p> <p>Methods</p> <p>Nine male subjects (19–25 yr; 83.3 ± 3.1 kg; 184 ± 2 cm), underwent three testing sessions administered in a randomized and double-blind fashion. During each session, subjects were provided 4 oz of water and a gelatin capsule containing a placebo, 1.5 mg/kg caffeine, or 3.0 mg/kg caffeine. After thirty minutes of rest, a warm-up (30 Watts for 2 min) the pedal rate of 60 rpm was maintained at a steady-state output of 60 watts for five minutes; increased to 120 watts for five minutes and to 180 watts for five minutes. After a 2 min rest the workload was 180 watts for one minute and increased by 30 watts every minute until exhaustion. Heart rate (HR) was measured during the last 15-seconds of each minute of submaximal exercise. Systolic blood pressure (BP) was measured at rest and during each of the three sub-maximal steady state power outputs. Minute ventilation (V<sub>E</sub>), Tidal volume (V<sub>T</sub>), Breathing frequency (Bf), Rating of perceived exertion (RPE), Respiratory exchange ratio (RER), and Oxygen consumption (VO<sub>2</sub>) were measured at rest and during each minute of exercise.</p> <p>Results</p> <p>Caffeine at 1.5 and 3.0 mg/kg body weight significantly lowered (p < 0.05) HR during all three submaximal exercise intensities compared to placebo (range – 4 to 7 bpm lower) but not at rest or maximal exercise. BP was significantly higher (p < 0.05) at rest and after the 3 mg/kg caffeine vs placebo (116 ± 13 vs 123 ± 10 mm Hg). Neither dose of caffeine had any effect on BP during submaximal exercise. Caffeine had no effect on V<sub>E</sub>, V<sub>T</sub>, VO<sub>2</sub>, RPE, maximal power output or time to exhaustion.</p> <p>Conclusion</p> <p>In non habitual caffeine users it appears that consuming a caffeine pill (1.5 & 3.0 mg/kg) at a dose comparable to 1–3 cups of coffee lowers heart rate during submaximal exercise but not at near maximal and maximal exercise. In addition, this caffeine dose also only appears to affect systolic blood pressure at rest but not during cycling exercise.</p

    Patients’ Perceptions of Memory Functioning Before and After Surgical Intervention to Treat Medically Refractory Epilepsy.

    Get PDF
    Purpose:One risk associated with epilepsy surgery is memory loss, but perhaps more important is how patients perceive changes in their memories. This longitudinal study evaluated changes in memory self-reports and investigated how self-reports relate to changes on objective memory measures in temporal or extratemporal epilepsy patients who underwent surgery. Methods: Objective memory (Wechsler Memory Scale–Revised) and subjective memory self-reports (Memory Assessment Clinics Self-Rating Scale) were individually assessed for 136 patients ∼6 months before and 6 months after surgery. A measure of depressive affect (Beck Depression Inventory–2nd Edition) was used to control variance attributable to emotional distress. Results: Despite a lack of significant correlational relationships between objective and subjective memory for the entire sample, significant correlations between objective memory scores and self-reports did emerge for a subset of patients who evidenced memory decline. Differences also were found in the subjective memory ratings of temporal lobe versus extratemporal patients. Temporal lobe patients rated their memories more negatively than did extratemporal patients and were more likely to report significant improvements in their memory after surgery. Conclusions: In general, patients were not accurate when rating their memories compared to other adults. However, patients with significant declines in their memories were sensitive to actual changes in their memories over time relative to their own personal baselines

    Does time of surgery influence the rate of false-negative appendectomies?:A retrospective observational study of 274 patients

    Get PDF
    Background Multiple disciplines have described an “after-hours effect” relating to worsened mortality and morbidity outside regular working hours. This retrospective observational study aimed to evaluate whether diagnostic accuracy of a common surgical condition worsened after regular hours. Methods Electronic operative records for all non-infant patients (age > 4 years) operated on at a single centre for presumed acute appendicitis were retrospectively reviewed over a 56-month period (06/17/2012–02/01/2017). The primary outcome measure of unknown diagnosis was compared between those performed in regular hours (08:00–17:00) or off hours (17:01–07:59). Pre-clinical biochemistry and pre-morbid status were recorded to determine case heterogeneity between the two groups, along with secondary outcomes of length of stay and complication rate. Results Out of 289 procedures, 274 cases were deemed eligible for inclusion. Of the 133 performed in regular hours, 79% were appendicitis, compared to 74% of the 141 procedures performed off hours. The percentage of patients with an unknown diagnosis was 6% in regular hours compared to 15% off hours (RR 2.48; 95% CI 1.14–5.39). This was accompanied by increased numbers of registrars (residents in training) leading procedures off hours (37% compared to 24% in regular hours). Pre-morbid status, biochemistry, length of stay and post-operative complication rate showed no significant difference. Conclusions This retrospective study suggests that the rate of unknown diagnoses for acute appendicitis increases overnight, potentially reflecting increased numbers of unnecessary procedures being performed off hours due to poorer diagnostic accuracy. Reduced levels of staffing, availability of diagnostic modalities and changes to workforce training may explain this, but further prospective work is required. Potential solutions may include protocolizing the management of common acute surgical conditions and making more use of non-resident on call senior colleagues

    Control of electronic conduction at an oxide heterointerface using surface polar adsorbates

    Full text link
    The transfer of electrons between a solid surface and adsorbed atomic or molecular species is fundamental in natural and synthetic processes, being at the heart of most catalytic reactions and many sensors. In special cases, metallic conduction can be induced at the surface of, for example, Si-terminated SiC1, or mixed-terminated ZnO2, in the presence of a hydrogen adlayer. Generally, only the surface atoms are significantly affected by adsorbates. However, remotely changing electronic states far from the adsorbed layer is possible if these states are electrostatically coupled to the surface. Here we show that the surface adsorption of common solvents such as acetone, ethanol, and water can induce a large change (factor of three) in the conductivity at the buried interface between SrTiO3 substrates and LaAlO3 thin films3-8. This phenomenon is observed only for polar solvents. Our result provides experimental evidence that adsorbates at the LaAlO3 surface induce accumulation of electrons at the LaAlO3/SrTiO3 interface, suggesting a general polarization-facilitated electronic transfer mechanism, which can be used for sensor applications.Comment: 14 pages, 4 figure
    corecore