New Approach to Silver Halide Photography Using Radical Cation Chemistry

A new mechanism for spectral sensitization of silver halide is described, which can potentially double the sensitivity of photographic emulsions. The photooxidized sensitizing dye is trapped using an organic donor molecule, which fragments to form a cation and a reducing radical, which injects an electron into the conduction band of the silver halide. In this way, two conduction-band electrons can be produced for each absorbed photon

Mechanisms of Inhaled Fine Particulate Air Pollution–Induced Arterial Blood Pressure Changes

Background: Epidemiologic studies suggest a positive association between fine particulate matter and arterial blood pressure, but the results have been inconsistent. Objectives: We investigated the effect of ambient particles on systemic hemodynamics during a 5-hr exposure to concentrated ambient air particles (CAPs) or filtered air (FA) in conscious canines. Methods: Thirteen dogs were repeatedly exposed via permanent tracheostomy to CAPs (358.1 ± 306.7 μg/m$^3$, mean ± SD) or FA in a crossover protocol (55 CAPs days, 63 FA days). Femoral artery blood pressure was monitored continuously via implanted telemetry devices. We measured baroreceptor reflex sensitivity before and after exposure in a subset of these experiments (n = 10 dogs, 19 CAPs days, 20 FA days). In additional experiments, we administered α-adrenergic blockade before exposure (n = 8 dogs, 16 CAPs days, 15 FA days). Blood pressure, heart rate, rate–pressure product, and baroreceptor reflex sensitivity responses were compared using linear mixed-effects models. Results: CAPs exposure increased systolic blood pressure (2.7 ± 1.0 mmHg, p = 0.006), diastolic blood pressure (4.1 ± 0.8 mmHg; p < 0.001), mean arterial pressure (3.7 ± 0.8 mmHg; p < 0.001), heart rate (1.6 ± 0.5 bpm; p < 0.001), and rate–pressure product (539 ± 110 bpm × mmHg; p < 0.001), and decreased pulse pressure (−1.7 ± 0.7 mmHg, p = 0.02). These changes were accompanied by a 20 ± 6 msec/mmHg (p = 0.005) increase in baroreceptor reflex sensitivity after CAPs versus FA. After α-adrenergic blockade, responses to CAPs and FA no longer differed significantly. Conclusions: Controlled exposure to ambient particles elevates arterial blood pressure. Increased peripheral vascular resistance may mediate these changes, whereas increased baroreceptor reflex sensitivity may compensate for particle-induced alterations in blood pressure

Dual Use of a Patient Portal and Clinical Video Telehealth by Veterans with Mental Health Diagnoses: Retrospective, Cross-Sectional Analysis

BACKGROUND: Access to mental health care is challenging. The Veterans Health Administration (VHA) has been addressing these challenges through technological innovations including the implementation of Clinical Video Telehealth, two-way interactive and synchronous videoconferencing between a provider and a patient, and an electronic patient portal and personal health record, My HealtheVet. OBJECTIVE: This study aimed to describe early adoption and use of My HealtheVet and Clinical Video Telehealth among VHA users with mental health diagnoses. METHODS: We conducted a retrospective, cross-sectional analysis of early My HealtheVet adoption and Clinical Video Telehealth engagement among veterans with one or more mental health diagnoses who were VHA users from 2007 to 2012. We categorized veterans into four electronic health (eHealth) technology use groups: My HealtheVet only, Clinical Video Telehealth only, dual users who used both, and nonusers of either. We examined demographic characteristics and mental health diagnoses by group. We explored My HealtheVet feature use among My HealtheVet adopters. We then explored predictors of My HealtheVet adoption, Clinical Video Telehealth engagement, and dual use using multivariate logistic regression. RESULTS: Among 2.17 million veterans with one or more mental health diagnoses, 1.51% (32,723/2,171,325) were dual users, and 71.72% (1,557,218/2,171,325) were nonusers of both My HealtheVet and Clinical Video Telehealth. African American and Latino patients were significantly less likely to engage in Clinical Video Telehealth or use My HealtheVet compared with white patients. Low-income patients who met the criteria for free care were significantly less likely to be My HealtheVet or dual users than those who did not. The odds of Clinical Video Telehealth engagement and dual use decreased with increasing age. Women were more likely than men to be My HealtheVet or dual users but less likely than men to be Clinical Video Telehealth users. Patients with schizophrenia or schizoaffective disorder were significantly less likely to be My HealtheVet or dual users than those with other mental health diagnoses (odds ratio, OR 0.50, CI 0.47-0.53 and OR 0.75, CI 0.69-0.80, respectively). Dual users were younger (53.08 years, SD 13.7, vs 60.11 years, SD 15.83), more likely to be white, and less likely to be low-income than the overall cohort. Although rural patients had 17% lower odds of My HealtheVet adoption compared with urban patients (OR 0.83, 95% CI 0.80-0.87), they were substantially more likely than their urban counterparts to engage in Clinical Video Telehealth and dual use (OR 2.45, 95% CI 1.95-3.09 for Clinical Video Telehealth and OR 2.11, 95% CI 1.81-2.47 for dual use). CONCLUSIONS: During this study (2007-2012), use of these technologies was low, leaving much potential for growth. There were sociodemographic disparities in access to My HealtheVet and Clinical Video Telehealth and in dual use of these technologies. There was also variation based on types of mental health diagnosis. More research is needed to ensure that these and other patient-facing eHealth technologies are accessible and effectively used by all vulnerable patients

Autonomic Effects of Controlled Fine Particulate Exposure in Young Healthy Adults: Effect Modification by Ozone

Background: Human controlled-exposure studies have assessed the impact of ambient fine particulate matter on cardiac autonomic function measured by heart rate variability (HRV), but whether these effects are modified by concomitant ozone exposure remains unknown. Objective: In this study we assessed the impact of O$_3$ and particulate matter exposure on HRV in humans. Methods: In a crossover design, 50 subjects (19–48 years of age) were randomized to 2-hr controlled exposures to filtered air (FA), concentrated ambient particles (CAPs), O$_3$, or combined CAPs and ozone (CAPs + O$_3$). The primary end point was change in HRV between the start and end of exposure. Secondary analyses included blood pressure (BP) responses, and effect modification by asthmatic status. Results: Achieved mean CAPs and O$_3$ exposure concentrations were 121.6 ± 48.0 μg/m$^3$ and 113.9 ± 6.6 ppb, respectively. In a categorical analysis, exposure had no consistent effect on HRV indices. However, the dose–response relationship between CAPs mass concentration and HRV indices seemed to vary depending on the presence of O$_3$. This heterogeneity was statistically significant for the low-frequency component of HRV (p = 0.02) and approached significance for the high-frequency component and time-domain measures of HRV. Exposure to CAPs + O$_3$ increased diastolic BP by 2.0 mmHg (SE, 1.2; p = 0.02). No other statistically significant changes in BP were observed. Asthmatic status did not modify these effects. Conclusion: The potentiation by O$_3$ of CAPs effects on diastolic BP and possibly HRV is of small magnitude in young adults. Further studies are needed to assess potential effects in more vulnerable populations

Particulate Matter (PM) Research Centers (1999–2005) and the Role of Interdisciplinary Center-Based Research

Objective: The U.S. Environmental Protection Agency funded five academic centers in 1999 to address the uncertainties in exposure, toxicity, and health effects of airborne particulate matter (PM) identified in the “Research Priorities for Airborne Particulate Matter” of the National Research Council (NRC). The centers were structured to promote interdisciplinary approaches to address research priorities of the NRC. In this report, we present selected accomplishments from the first 6 years of the PM Centers, with a focus on the advantages afforded by the interdisciplinary, center-based research approach. The review highlights advances in the area of ultrafine particles and traffic-related health effects as well as cardiovascular and respiratory effects, mechanisms, susceptibility, and PM exposure and characterization issues. Data sources and synthesis: The collective publications of the centers served as the data source. To provide a concise synthesis of overall findings, authors representing each of the five centers identified a limited number of topic areas that serve to illustrate the key accomplishments of the PM Centers program, and a consensus statement was developed. Conclusions: The PM Centers program has effectively applied interdisciplinary research approaches to advance PM science

Practical lessons learned for assessing and treating bipolar disorder via telehealth modalities during the COVID-19 pandemic

We briefly frame challenges and steps to overcoming those challenges in delivering care for patients with bipolar disorder via telehealth or telephone during COVID-19. Telehealth provides an invaluable opportunity to provide care for patients even under circumstances of social isolation. The issues discussed in this debate are intended to guide and assist clinicians, both in assessment and intervention, in adjusting to the use of virtual care for patients with bipolar disorder