On-line mass spectrometric monitoring of the polymerization of a phenolic-resin-based material

Polymerization of phenolic-resin-based materials requires elevated temperatures. The low thermal conductivity of these materials has led to the use of dielectric heating techniques in lieu of standard convection oven heating to obtain a satisfactory cure. The curing rate and therefore the quality of the cured material depends on the heating rate and maximum temperature attained, parameters which are extremely difficult to measure in dielectric heating units. The dielectric curing of these materials was monitored by using a mass spectrometer to measure the partial pressure of phenol in the gas evolved during polymerization. The resulting plots of phenol partial pressure as a function of time have a characteristic shape, and these may be used to indicate the attainment of complete curing. The validity of the mass spectrometric technique was confirmed by chemical analysis of the polymerized samples

Research Update: Density functional theory investigation of the interactions of silver nanoclusters with guanine

Citation: Dale, B. B., Senanayake, R. D., & Aikens, C. M. (2017). Research Update: Density functional theory investigation of the interactions of silver nanoclusters with guanine. APL Materials, 5(5). doi:10.1063/1.4977795Bare and guanine-complexed silver clusters Agnz (n = 2-6; z = 0-2) are examined using density functional theory to elucidate the geometries and binding motifs that are present experimentally. Whereas the neutral systems remain planar in this size range, a 2D-3D transition occurs at Ag5+ for the cationic system and at Ag42+ for the dicationic system. Neutral silver clusters can bind with nitrogen 3 or with the pi system of the base. However, positively charged clusters interact with nitrogen 7 and the neighboring carbonyl group. Thus, the cationic silver-DNA clusters present experimentally may preferentially interact at these sites. © 2017 Author(s)

Quantum coherent plasmon in silver nanowires: a real-time TDDFT study

A plasmon-like phenomenon, arising from coinciding resonant excitations of different electronic characteristics in 1D silver nanowires, has been proposed based on theoretical linear absorption spectra. Such a molecular plasmon holds the potential for anisotropic nanoplasmonic applications. However, its dynamical nature remains unexplored. In this work, quantum dynamics of longitudinal and transverse excitations in 1D silver nanowires are carried out within the real-time time-dependent density functional theory framework. The anisotropic electron dynamics confirm that the transverse transitions of different electronic characteristics are collective in nature and oscillate in-phase with respect to each other. Analysis of the time evolutions of participating one-electron wave functions suggests that the transverse transitions form a coherent wave packet that gives rise to a strong plasmon resonance at the molecular level

Industrial Energy Development Decouples Ungulate Migration from the Green Wave

The ability to freely move across the landscape to track the emergence of nutritious spring green-up (termed ‘green-wave surfing’) is key to the foraging strategy of migratory ungulates. Across the vast landscapes traversed by many migratory herds, habitats are being altered by development with unknown consequences for surfing. Using a unique long-term tracking dataset, we found that when energy development occurs within mule deer (Odocoileus hemionus) migration corridors, migrating animals become decoupled from the green wave. During the early phases of a coalbed natural gas development, deer synchronized their movements with peak green-up. But faced with increasing disturbance as development expanded, deer altered their movements by holding up at the edge of the gas field and letting the green wave pass them by. Development often modified only a small portion of the migration corridor but had far-reaching effects on behaviour before and after migrating deer encountered it, thus reducing surfing along the entire route by 38.65% over the 14-year study period. Our study suggests that industrial development within migratory corridors can change the behaviour of migrating ungulates and diminish the benefits of migration. Such disruptions to migratory behaviour present a common mechanism whereby corridors become unprofitable and could ultimately be lost on highly developed landscapes

Association between depression and concurrent Type 2 diabetes outcomes varies by diabetes regimen

Aims  Although depression has weak associations with several Type 2 diabetes mellitus (DM) outcomes, it is possible that these associations are concentrated within certain patient subgroups that are more vulnerable to their effects. This study tested the hypothesis that depression is related to glycaemic control and diabetes-related quality of life (DQOL) in patients who are prescribed injected insulin, but not those on oral glucose-lowering agents alone. Methods  Participants (103 on insulin, 155 on oral glucose-lowering agents alone) with Type 2 DM were recruited from a large US healthcare system and underwent assessment of glycaemic control (glycated haemoglobin; HbA 1c ), medication adherence and diabetes self-care behaviours, DQOL and depression (none, mild, moderate/severe). Results  There was a significant regimen × depression interaction on HbA 1c ( P  = 0.002), such that depression was associated with HbA 1c in patients using insulin (β = 0.35, P  < 0.001) but not in patients using oral agents alone (β = –0.08, P  = NS). There was a similar interaction when quality of life was analysed as an outcome ( P  = 0.002). Neither effect was mediated by regimen adherence. Conclusions  The generally weak association between depression and glycaemic control is concentrated among patients who are prescribed insulin. Similarly, the association between depression and illness quality of life is strongest in patients prescribed insulin. Because this is not attributable to depression-related adherence problems, psychophysiological mechanisms unique to this group ought to be carefully investigated. Clinicians might be especially vigilant for depression in Type 2 DM patients who use insulin and consider its potential impact upon their illness course. Diabet. Med. 25, 1324–1329 (2008)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73538/1/j.1464-5491.2008.02590.x.pd

Prevalence of nonadherence with maintenance mesalamine in quiescent ulcerative colitis

There are scant data regarding outpatient adherence in quiescent ulcerative colitis aside from patients enrolled in controlled clinical trials. We conducted a prevalence study to determine the medication adherence rate of maintenance therapy and to identify possible risk factors for nonadherence. METHODS : Outpatients with clinically quiescent ulcerative colitis for >6 months on maintenance mesalamine (Asacol, Procter and Gamble, Cincinnati, OH) were eligible. Patients were interviewed regarding disease history, and demographics were obtained from medical records. Refill information for at least 6 months was obtained from computerized pharmacy records. Adherence was defined as at least 80% consumption of supply dispensed. Using nonadherence as the outcome of interest, stratified analysis and regression modeling were used to identify significant associations. RESULTS : Data were complete for the 94 patients recruited. The overall adherence rate was found to be 40%. The median amount of medication dispensed per patient was 71% (8–130%) of the prescribed regimen. Nonadherent patients were more likely to be male (67% vs 52%, p < 0.05 ), single (68% vs 53%, p = 0.04 ), and to have disease limited to the left side of the colon versus pancolitis (83% vs 51%, p < 0.01 ). Sixty-eight percent of patients who took more than four prescription medications were found to be nonadherent versus only 40% of those patients taking fewer medications ( p = 0.05 ). Age, occupation, a family history of inflammatory bowel disease, length of remission, quality-of-life score, or method of recruitment (telephone interview vs clinical visit) were not associated with nonadherence. Logistic regression identified that a history of more than four prescriptions (odds ratio [OR] 2.5 [1.4–5.7]) and male gender (OR 2.06 [1.17–4.88]) increased the risk of nonadherence. Two statistically significant variables, which were protective against nonadherence, were endoscopy within the past 24 months (OR 0.96 [0.93–0.99]) and being married (OR 0.46 [0.39–0.57]). CONCLUSION : Nonadherence is associated with multiple concomitant medications, male gender, and single status. These patient characteristics may be helpful in targeting those patients at higher risk for nonadherence.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75640/1/j.1572-0241.2001.04683.x.pd

A Moment of Mindfulness: Computer-Mediated Mindfulness Practice Increases State Mindfulness

Three studies investigated the use of a 5-minute, computer-mediated mindfulness practice in increasing levels of state mindfulness. In Study 1, 54 high school students completed the computer-mediated mindfulness practice in a lab setting and Toronto Mindfulness Scale (TMS) scores were measured before and after the practice. In Study 2 (N = 90) and Study 3 (N = 61), the mindfulness practice was tested with an entirely online sample to test the delivery of the 5-minute mindfulness practice via the internet. In Study 2 and 3, we found a significant increase in TMS scores in the mindful condition, but not in the control condition. These findings highlight the impact of a brief, mindfulness practice for single-session, computer-mediated use to increase mindfulness as a state

stratamatch: Prognostic Score Stratification Using a Pilot Design

Optimal propensity score matching has emerged as one of the most ubiquitous approaches for causal inference studies on observational data. However, outstanding critiques of the statistical properties of propensity score matching have cast doubt on the statistical efficiency of this technique, and the poor scalability of optimal matching to large data sets makes this approach inconvenient if not infeasible for sample sizes that are increasingly commonplace in modern observational data. The stratamatch package provides implementation support and diagnostics for ‘stratified matching designs,’ an approach that addresses both of these issues with optimal propensity score matching for large-sample observational studies. First, stratifying the data enables more computationally efficient matching of large data sets. Second, stratamatch implements a ‘pilot design’ approach in order to stratify by a prognostic score, which may increase the precision of the effect estimate and increase power in sensitivity analyses of unmeasured confounding

A pilot randomized controlled trial for a videoconference-delivered mindfulness-based group intervention in a nonclinical setting

Technology is increasingly being integrated into the provision of therapy and mental health interventions. While the evidence base for technology-led delivery of mindfulness-based interventions is growing, one approach to understanding the effects of technology-delivered elements includes so-named blended programs that continue to include aspects of traditional face-to-face interaction. This arrangement offers unique practical advantages, and also enables researchers to isolate variables that may be underlying the effects of technology-delivered interventions. The present study reports on a pilot videoconference-delivered mindfulness-based group intervention offered to university students and staff members with wait-list controls. Apart from the first session of the six-week course, the main facilitator guided evening classes remotely via online videoconferencing, with follow-up exercises via email. Participants Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation were taught a variety of mindfulness-based exercises such as meditation, breathing exercises, mindful tasting, as well as the concepts underpinning such practice. Participants completed pre- and post-intervention questionnaires on depression, anxiety, repetitive negative thinking, dysfunctional attitudes, positive and negative affect, self-compassion, compassion for others, and mindfulness. For participants who attended at least five of the six sessions, scores on all outcome measures improved significantly post intervention and remained stable at three-week follow up. The videoconference-delivered mindfulness-based group intervention appears to provide a viable alternative format to standard mindfulness programs where the facilitator and participants need to live in close physical proximity with each other