Accurate estimates of particle surface tension are required for models concerning atmospheric aerosol nucleation and activation. However, it is difficult to collect the volumes of atmospheric aerosol ...required by typical instruments that measure surface tension, such as goniometers or Wilhelmy plates. In this work, a method that measures, ex situ, the surface tension of collected liquid nanoparticles using atomic force microscopy is presented. A film of particles is collected via impaction and is probed using nanoneedle tips with the atomic force microscope. This micro-Wilhelmy method allows for direct measurements of the surface tension of small amounts of sample. This method was verified using liquids, whose surface tensions were known. Particles of ozone oxidized α-pinene, a well-characterized system, were then produced, collected, and analyzed using this method to demonstrate its applicability for liquid aerosol samples. It was determined that oxidized α-pinene particles formed in dry conditions have a surface tension similar to that of pure α-pinene, and oxidized α-pinene particles formed in more humid conditions have a surface tension that is significantly higher.
Preclinical and clinical data have shown that D-cycloserine (DCS), a partial agonist at the N-methyl-d-aspartate receptor complex, augments the retention of fear extinction in animals and the ...therapeutic learning from exposure therapy in humans. However, studies with non-clinical human samples in de novo fear conditioning paradigms have demonstrated minimal to no benefit of DCS. The aim of this study was to evaluate the effects of DCS on the retention of extinction learning following de novo fear conditioning in a clinical sample. Eighty-one patients with social anxiety disorder were recruited and underwent a previously validated de novo fear conditioning and extinction paradigm over the course of three days. Of those, only 43 (53%) provided analyzable data. During conditioning on Day 1, participants viewed images of differently colored lamps, two of which were followed by with electric shock (CS+) and a third which was not (CS-). On Day 2, participants were randomly assigned to receive either 50 mg DCS or placebo, administered in a double-blind manner 1 hour prior to extinction training with a single CS+ in a distinct context. Day 3 consisted of tests of extinction recall and renewal. The primary outcome was skin conductance response to conditioned stimuli, and shock expectancy ratings were examined as a secondary outcome. Results showed greater skin conductance and expectancy ratings in response to the CS+ compared to CS- at the end of conditioning. As expected, this difference was no longer present at the end of extinction training, but returned at early recall and renewal phases on Day 3, showing evidence of return of fear. In contrast to hypotheses, DCS had no moderating influence on skin conductance response or expectancy of shock during recall or renewal phases. We did not find evidence of an effect of DCS on the retention of extinction learning in humans in this fear conditioning and extinction paradigm.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Highlights • Participants were 103 acute-care psychiatric inpatients. • Distress tolerance was evaluated multimodally with regard to PTSD symptoms. • Self-reported distress tolerance was negatively ...associated with PTSD severity. • Breath-holding duration was positively associated with PTSD arousal severity. • Trauma load, substance use, gender, race, and social status were included in models.
It is well known that atmospheric aerosol size and composition impact air quality, climate, and health. The aerosol composition is typically a mixture and consists of a wide range of organic and ...inorganic particles that interact with each other. Furthermore, water vapor is ubiquitous in the atmosphere, in indoor air, and within the human body’s respiratory system, and the presence of water can alter the aerosol morphology and propensity to form droplets. Specifically, aerosol mixtures can undergo liquid–liquid phase separation (LLPS) in the presence of water vapor. However, the experimental conditions for which LLPS impacts water uptake and the subsequent prediction of aerosol mixtures are poorly understood. To improve our understanding of aerosol mixtures and droplets, this study explores two ternary systems that undergo LLPS, namely, the 2MGA system (sucrose + ammonium sulfate + 2-methylglutaric acid) and the PEG1000 system (sucrose + ammonium sulfate + polyethylene glycol 1000). In this study, the ratio of species and the O:C ratios are systematically changed, and the hygroscopic properties of the resultant aerosol were investigated. Here, we show that the droplet activation above 100% RH of the 2MGA system was influenced by LLPS, while the droplet activation of the PEG1000 system was observed to be linearly additive regardless of chemical composition, O:C ratio, and LLPS. A theoretical model that accounts for LLPS with O:C ratios was developed and predicts the water uptake of internally mixed systems of different compositions and phase states. Hence, this study provides a computationally efficient algorithm to account for the LLPS and solubility parameterized by the O:C ratio for droplet activation at supersaturated relative humidity conditions and may thus be extended to mixed inorganic–organic aerosol populations with unspeciated organic composition found in the ambient environment.
The e-fluid heated in electronic cigarettes (e-cigarettes) is largely composed of organic compounds, specifically propylene glycol, vegetable glycerin and flavouring compounds. When heated, as it is ...in an e-cigarette, the chemical species in this fluid have the potential to oxidise into carbon monoxide (CO) and other species. Using diode laser spectroscopy, the concentration of CO in e-cigarette mainstream effluent as a function of e-cigarette power and flavour was measured. Carbon monoxide concentration was found to be a direct function of the power of the resistive heating. At the highest powers testable using commercial e-cigarette components, the maximum CO concentration measured was over 180 ppm. The flavouring compounds in the e-fluid also had an effect on the concentration of carbon monoxide present in the effluent.
Abstract Heavy users and addicted individuals have shown to develop an approach action tendency – or approach bias – toward stimuli related to the substance of interest. Emerging evidence points to ...approach bias retraining (ABR) as an effective aid for the treatment of addictive behaviors. The current study seeks to extend this work by testing, in a pilot study, whether standard smoking cessation treatment involving cognitive-behavioral therapy (CBT) and nicotine replacement therapy can be augmented by ABR. To this end, we will randomly assign 100 adult smokers to either ABR-augmented treatment or placebo-augmented treatment and compare the two conditions on short-term and long-term abstinence rates. The hope is that the findings of this study can inform treatment development for adult smokers.
The present study meta-analytically reviewed the effects of exercise on four transdiagnostic treatment targets: anxiety sensitivity (AS), distress tolerance (DT), stress reactivity (SR), and general ...self-efficacy (GSE).
We conducted systematic searches of peer-reviewed studies in bibliographical databases (Cochrane Library, psychINFO, PubMed) before April 1, 2018. Only randomized controlled trials (RCT) evaluating the effect of exercise on AS, DT, SR, or GSE using at least one validated outcome instrument in a sample of adolescents (≥13 years old) or adults were selected. We employed a meta-analysis of effects using random-effects pooling modeling for each treatment target.
The systematic search yielded 28 RCTs meeting eligibility criteria. Exercise interventions had a large effect on reducing AS (six studies, Hedges's g = 0.72, p = .001), a medium effect on increasing GSE (eight studies, Hedges's g = 0.59, p < .001), and a small effect on reducing SR (ten studies, Hedges's g = 0.32, p < .001). Evidence from four studies suggested that exercise interventions had a small but non-significant effect on increasing DT (Hedges's g = 0.21, p = .26).
This meta-analysis provides preliminary evidence exercise can engage certain transdiagnostic targets. Further research is required to optimize exercise intervention parameters to achieve the strongest effects on these important mechanistic variables.
•We examined the effects of exercise on four transdiagnostic treatment targets.•Exercise interventions have a medium-large effect on reducing anxiety sensitivity.•Exercise interventions have a medium effect of increasing general self-efficacy.•Exercise interventions have a small effect on reducing stress reactivity.•Exercise interventions have a non-significant effect on distress tolerance.
Five new instruments for semicontinuous measurements of fine particle (PM2.5) nitrate and sulfate were deployed in the Atlanta Supersite Experiment during an intensive study in August 1999. The ...instruments measured bulk aerosol chemical composition at rates ranging from every 5 min to once per hour. The techniques included a filter sampling system with automated water extraction and online ion chromatographic (IC) analysis, two systems that directly collected particles into water for IC analysis, and two techniques that converted aerosol nitrate or sulfate either catalytically or by flash vaporization to gaseous products that were measured with gas analyzers. During the one‐month study, 15‐min integrated nitrate concentrations were low, ranging from about 0.1 to 3.5 μg m−3 with a mean value of 0.5 μg m−3. Ten‐minute integrated sulfate concentrations varied between 0.3 and 40 μg m−3 with a mean of 14 μg m−3. By the end of the one‐month study most instruments were in close agreement, with r‐squared values between instrument pairs typically ranging from 0.7 to 0.94. Based on comparison between individual semicontinuous devices and 24‐hour integrated filter measurements, most instruments were within 20–30% for nitrate (∼0.1–0.2 μg m−3) and 10–15% for sulfate (1–2 μg m−3). Within 95% confidence intervals, linear regression fits suggest that no biases existed between the semicontinuous techniques and the 24‐hour integrated filter measurements of nitrate and sulfate;, however, for nitrate, the semicontinuous intercomparisons showed significantly less variability than intercomparisons amongst the 24‐hour integrated filters.
The authors hypothesize that environmental values derive from a sense of connectivity with nature. Connectivity describes a perception of sameness between the self, others, and the natural world. The ...experience of connectivity involves dissolution of boundaries and a sense of a shared or common essence between the self, nature, and others. Connectivity with nature differs theoretically and operationally from other explanations of environmental values, including cultural bias, postmaterialism, and social altruism. The authors describe their development of a sociometric scale to operationalize connectivity with nature. Based on data from a mail survey of Pennsylvania landowners, the authors use multiple regression analyses to determine the extent to which connectivity with nature predicts and explains environmental concern and behavior in the presence of standard sociodemographic variables. Survey respondents reported a high level of connectivity with nature, and connectivity retained a significant and positive relationship to environmental concern and environmental behavior in multiple regression models. Implications of these findings are advanced.
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