Decomposing the late positive potential to cannabis cues in regular cannabis users: A temporal-spatial principal component analysis.

Cannabis use disorder (CUD) is increasing in the United States, yet, specific neural mechanisms of CUD are not well understood. Disordered substance use is characterized by heightened drug cue incentive salience, which can be measured using the late positive potential (LPP), an event-related potential (ERP) evoked by motivationally significant stimuli. The drug cue LPP is typically quantified by averaging the slow wave's scalp-recorded amplitude across its entire time course, which may obscure distinct underlying factors with differential predictive validity; however, no study to date has examined this possibility. In a sample of 105 cannabis users, temporo-spatial Principal Component Analysis was used to decompose cannabis cue modulation of the LPP into its underlying factors. Acute stress was also inducted to allow for identification of specific cannabis LPP factors sensitive to stress. Factor associations with CUD severity were also explored. Eight factors showed significantly increased amplitudes to cannabis images relative to neutral images. These factors spanned early (~372 ms), middle (~824 ms), and late (>1000 ms) windows across frontal, central, and parietal-occipital sites. CUD phenotype individual differences were primarily associated with frontal, middle/late latency factor amplitudes. Acute stress effects were limited to one early central and one late frontal factor. Taken together, results suggest that the cannabis LPP can be decomposed into distinct, temporal-spatial factors with differential responsivity to acute stress and CUD phenotype variability. Future individual difference studies examining drug cue modulation of the LPP should consider (1) frontalcentral poolings in addition to conventional central-parietal sites, and (2) later LPP time windows.

The revised Clinician-Administered PTSD scale for DSM-5 (CAPS-5-R): Initial psychometric evaluation in a trauma-exposed community sample.

The Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) is a widely used, well-validated structured interview for posttraumatic stress disorder (PTSD). It was recently revised to improve various aspects of administration and scoring. We conducted a psychometric evaluation of the revised version, known as the CAPS-5-R. Participants were 73 community residents with mixed trauma exposure (e.g., sexual assault, physical assault, transportation accident, the unnatural death of a loved one). CAPS-5-R PTSD diagnosis demonstrated good test-retest reliability, кs = .73-.79; excellent interrater reliability, кs = .86-.93; and good-to-excellent alternate forms reliability with the CAPS-5, кs = .79-.93. In addition, the CAPS-5-R total PTSD severity score demonstrated excellent test-retest reliability, intraclass correlation coefficient (ICC) = .86; interrater reliability, ICC = .98; and alternate forms reliability with the CAPS-5, r = .95. Further, the CAPS-5-R demonstrated good convergent validity with other measures of PTSD and good discriminant validity with measures of other constructs (e.g., depression, anxiety, alcohol problems, somatic concerns, mania). Given its strong psychometric performance in this study, as well as its improvements in administration and scoring, the CAPS-5-R appears to be a valuable update of the current CAPS-5.

Cognitive reappraisal and the association between depressive symptoms and perceived social support among older adults.

OBJECTIVES: There is an association between depression and diminished social support; indeed, interpersonal dysfunction is often a central feature of depression. The purpose of this study is to examine the role that an emotion regulation (ER) strategy, cognitive reappraisal, plays in influencing the association between depressive symptoms and perceived social support in older adults. METHOD: Data for this cross-sectional study come from a community-based survey of older adults (60+, N = 910). We examined the effects of depressive symptoms and cognitive reappraisal on perceived social support. We then examined the potential moderating role of cognitive reappraisal on the association between depressive symptoms and perceived social support. RESULTS: Depressive symptoms were associated with lower levels of perceived social support. Cognitive reappraisal was associated with higher levels of perceived social support. Cognitive reappraisal moderated the negative consequences of depressive symptoms on perceived social support. Whereas depressive symptoms had a negative effect on perceived social support, the negative effect was greater for those with lower levels of cognitive reappraisal compared to those with higher levels of cognitive reappraisal. DISCUSSION: ER strategies may play a role in attenuating the negative consequences of depressive symptoms on social support in older age. It may be possible to help individuals maintain social support in later life, even in the face of mental health challenges, if they cultivate ER skills.

Data-Driven Investigation of Monosilane and Ammonia Co-Pyrolysis to Silicon-Nitride-Based Ceramic Nanomaterials.

With its high strength, high thermal stability, low density, and high electrical resistance, silicon-nitride-based ceramics have been widely used as gate insulating layers, oxidation masks, and passivation layers. Employing SiN nanomaterials in anode applications also improves rate performances and cycling stability of the lithium-ion batteries. However, a fundamental understanding of the SiN synthetic process remains elusive. SiN gas-phase synthesis can be tailored with a comprehensive understanding of the underlying thermodynamics. In comparison to the characterization data available for solid-state SiN materials, high-level theoretical studies on gas-phase materials possessing Si-N bonds and comprehensive investigation of the SiN chemistry, particularly for nanoclusters, are very uncommon. Thus, we performed a theoretical study of Si and SiN alloy acyclic hydrides and polycyclic clusters to predict electronic structures and thermochemistry using quantum chemical calculation and statistical thermodynamics. Electronic properties by way of highest and lowest occupied molecular orbital energy gap and natural bonding orbitals analysis were calculated to explore the influence of elemental composition and geometry on the stability. Our studies provide characteristic data of SiN species for a data-driven approach to map the design space for discovery of novel silicon-nitride-based ceramic materials for advanced electronic and coating applications.

Development of the Adult ECMO Specialist Certification Examination.

The American Society of Extracorporeal Technology Board of Directors, consistent with the American Society of Extracorporeal Technology's safe patient care improvement mission, charged the International Board of Blood Management to write a knowledge and skill certification examination for healthcare personnel employed as adult extracorporeal membrane oxygenation (ECMO) specialists. Nineteen nationally recognized ECMO subject-matter experts were selected to complete the examination development. A job analysis was performed, yielding a job description and examination plan focused on 16 job categories. Multiple-choice test items were created and validated. Qualified ECMO specialists were identified to complete a pilot examination and both pre- and post-examination surveys. The examination item difficulty and candidate performance were ranked and matched using Rasch methodology. Candidates' examination scores were compared with their profession, training, and experience as ECMO specialists. The 120-item pilot examination form ranked 76 ECMO specialist candidates consistent with their licensure, ECMO training, and clinical experience. Forty-three registered nurses, 28 registered respiratory therapists, four certified clinical perfusionists, and one physician assistant completed the pilot examination process. Rasch statistics revealed examination reliability coefficients of .83 for candidates and .88 for test items. Candidates ranked the appropriateness for examination items consistent with the item content, difficulty, and their personal examination score. The pilot examination pass rate was 80%. The completed examination product scheduled for enrollment in March 2020 includes 100 verified test items with an expected pass rate of 84% at a cut score of 67%. The online certification examination based on a verified job analysis provides an extramural assessment that ranks minimally prepared ECMO specialists' knowledge, skills, and abilities (KSA) consistent with safe ECMO patient care and circuit management. It is anticipated that ECMO facilities and ECMO service providers will incorporate the certification examination as part of their process improvement, safety, and quality assurance plans.

Emotion dysregulation as a maintenance factor for posttraumatic stress symptoms: The role of anxiety sensitivity.

OBJECTIVES: The current study tested whether emotion dysregulation, assessed by the Difficulties in Emotion Regulation Scale (DERS), would predict posttraumatic stress symptoms (PTSS) through anxiety sensitivity (AS). Alternate cognitive-affective mediators (i.e., distress tolerance and intolerance of uncertainty) were explored. METHOD: A total of 259 trauma-exposed community members (ages averaging 37.39; evenly distributed by gender) from a larger clinical trial targeting suicide risk factors completed a clinical interview and self-report questionnaires at baseline, Week-3, and 1-month follow-up appointments. RESULTS: AS at Week 3 significantly mediated the relationship between initial emotion dysregulation and 1-month follow-up posttraumatic stress symptoms (PTSS) after controlling for condition and baseline symptoms (ß = .07; standard error = 0.03; 95% confidence interval = [0.01, 0.14]). Effects held for one out of six emotion dysregulation subscales. Distress tolerance and intolerance of uncertainty were not significant mediators (ps > .05). CONCLUSIONS: This study demonstrates that emotion dysregulation may confer maintenance of PTSS through AS. Findings highlight potentially malleable targets for interventions.

Primary vs. secondary H-atom abstraction in the Cl-atom reaction with n-pentane.

Velocity map imaging (VMI) measurements and quasi-classical trajectory (QCT) calculations on a newly developed, global potential energy surface (PES) combine to reveal the detailed mechanisms of reaction of Cl atoms with n-pentane. Images of the HCl (v = 0, J = 1, 2 and 3) products of reaction at a mean collision energy of 33.5 kJ mol-1 determine the centre-of-mass frame angular scattering and kinetic energy release distributions. The HCl products form with relative populations of J = 0-5 levels that fit to a rotational temperature of 138 ± 13 K. Product kinetic energy release distributions agree well with those derived from a previous VMI study of the pentyl radical co-product [Estillore et al., J. Chem. Phys. 2010, 132, 164313], but the angular distributions show more pronounced forward scattering. The QCT calculations reproduce many of the experimental observations, and allow comparison of the site-specific dynamics of abstraction of primary and secondary H-atoms. They also quantify the relative reactivity towards Cl atoms of the three different H-atom environments in n-pentane.

Dynamical Effects and Product Distributions in Simulated CN + Methane Reactions.

Dynamics of collisions between structured molecular species quickly become complex as molecules become large. Reactions of methane with halogen and oxygen atoms serve as model systems for polyatomic molecule chemical dynamics, and replacing the atomic reagent with a diatomic radical affords further insights. A new, full-dimensional potential energy surface for collisions between CN + CH4 to form HCN + CH3 is developed and then used to perform quasi-classical simulations of the reaction. Coupled-cluster energies serve as input to an empirical valence bonding (EVB) model, which provides an analytical function for the surface. Efficient sampling permits simulation of velocity-map ion images and exploration of dynamics over a range of collision energies. Reaction populates HCN vibration, and energy partitioning changes with collision energy. The reaction cross-section depends on the orientation of the diatomic CN radical. A two-dimensional extension of the cone of acceptance for an atom in the line-of-centers model appropriately describes its reactivity. The simulation results foster future experiments and diatomic extensions to existing atomic models of chemical collisions and reaction dynamics.

Evidence for concerted ring opening and C-Br bond breaking in UV-excited bromocyclopropane.

Photodissociation of gaseous bromocyclopropane via its A-band continuum has been studied at excitation wavelengths ranging from 230 nm to 267 nm. Velocity-map images of ground-state bromine atoms (Br), spin-orbit excited bromine atoms (Br(∗)), and C3H5 hydrocarbon radicals reveal the kinetic energies of these various photofragments. Both Br and Br(∗) atoms are predominantly generated via repulsive excited electronic states in a prompt photodissociation process in which the hydrocarbon co-fragment is a cyclopropyl radical. However, the images obtained at the mass of the hydrocarbon radical fragment identify a channel with total kinetic energy greater than that deduced from the Br and Br(∗) images, and with a kinetic energy distribution that exceeds the energetic limit for Br + cyclopropyl radical products. The velocity-map images of these C3H5 fragments have lower angular anisotropies than measured for Br and Br(∗), indicating molecular restructuring during dissociation. The high kinetic energy C3H5 signals are assigned to allyl radicals generated by a minor photochemical pathway which involves concerted C-Br bond dissociation and cyclopropyl ring-opening following single ultraviolet (UV)-photon absorption. Slow photofragments also contribute to the velocity map images obtained at the C3H5 radical mass, but the corresponding slow Br atoms are not observed. These features in the images are attributed to C3H5 (+) from the photodissociation of the C3H5Br(+) molecular cation following two-photon ionization of the parent compound. This assignment is confirmed by 118-nm vacuum ultraviolet ionization studies that prepare the molecular cation in its ground electronic state prior to UV photodissociation.

Survival in children on extracorporeal membrane oxygenation at the time of lung transplantation.

Limited data exist on ECMO at the time of LTx in children. The UNOS database was queried from 2000 to 2013 for pediatric lung transplant recipients (<18 yr) to assess post-transplant survival of patients on ECMO at the time of LTx. Of 587 pediatric recipients with 17 on ECMO, 585 were used for univariate and Kaplan-Meier function analysis, 535 for multivariate Cox models, and 24 for propensity score matching. Univariate Cox (HR = 1.777; 95% CI: 0.658, 4.803; p = 0.257) and Kaplan-Meier function (log-rank test: chi-square (df = 1): 1.32, p = 0.250) analyses did not identify a survival difference between ECMO and non-ECMO, while multivariate Cox models (HR = 1.821; 95% CI: 0.654, 5.065; p = 0.251) did not demonstrate an increased risk for death. Propensity score matching analysis (HR = 1.500; 95% CI: 0.251, 8.977; p = 0.657) also failed to demonstrate a significantly increased hazard ratio. Using a contemporary cohort of pediatric lung transplant recipients, the use of ECMO at the time of lung transplantation did not negatively impact survival.

Empirical Valence Bond Theory Studies of the CH4 + Cl → CH3 + HCl Reaction.

We report a theoretical investigation of the CH4 + Cl hydrogen abstraction reaction in the framework of empirical valence bond (EVB) theory. The main purpose of this study is to benchmark the EVB method against previous experimental and theoretical work. Analytical potential energy surfaces for the reaction have been developed on which quasi-classical trajectory calculations were carried out. The surfaces agree well with ab initio calculations at stationary points along the reaction path and dynamically relevant regions outside the reaction path. The analysis of dynamical data obtained using the EVB method, such as vibrational, rotational, and angular distribution functions, shows that this method compares well to both experimental measurements and higher-level theoretical calculations, with the additional benefit of low computational cost.

Computational Study of Competition between Direct Abstraction and Addition-Elimination in the Reaction of Cl Atoms with Propene.

Quasi-classical trajectory calculations on a newly constructed and full-dimensionality potential energy surface (PES) examine the dynamics of the reaction of Cl atoms with propene. The PES is an empirical valence bond (EVB) fit to high-level ab initio energies and incorporates deep potential energy wells for the 1-chloropropyl and 2-chloropropyl radicals, a direct H atom abstraction route to HCl + allyl radical (CH2CHCH2(•)) products (Δ(r)H(298K)(⊖) = −63.1 kJ mol(-1)), and a pathway connecting these regions. In total, 94 000 successful reactive trajectories were used to compute distributions of angular scattering and HCl vibrational and rotational level populations. These measures of the reaction dynamics agree satisfactorily with available experimental data. The dominant reaction pathway is direct abstraction of a hydrogen atom from the methyl group of propene occurring in under 500 fs. Less than 10% of trajectories follow an addition­elimination route via the two isomeric chloropropyl radicals. Large amplitude motions of the Cl about the propene molecular framework couple the addition intermediates to the direct abstraction pathway. The EVB method provides a good description of the complicated PES for the Cl + propene reaction despite fitting to a limited number of ab initio points, with the further advantage that dynamics specific to certain mechanisms can be studied in isolation by switching off coupling terms in the EVB matrix connecting different regions of the PES.

Vibrational Excitation of Both Products of the Reaction of CN Radicals with Acetone in Solution.

Transient electronic and vibrational absorption spectroscopy unravel the mechanisms and dynamics of bimolecular reactions of CN radicals with acetone in deuterated chloroform solutions. The CN radicals are produced by ultrafast ultraviolet photolysis of dissolved ICN. Two reactive forms of CN radicals are distinguished by their electronic absorption bands: "free" (uncomplexed) CN radicals, and "solvated" CN radicals that are complexed with solvent molecules. The lifetimes of the free CN radicals are limited to a few picoseconds following their photolytic production because of geminate recombination to ICN and INC, complexation with CDCl3 molecules, and reaction with acetone. The acetone reaction occurs with a rate coefficient of (8.0 ± 0.5) × 10(10) M(-1) s(-1) and transient vibrational spectra in the C═N and C═O stretching regions reveal that both the nascent HCN and 2-oxopropyl (CH3C(O)CH2) radical products are vibrationally excited. The rate coefficient for the reaction of solvated CN with acetone is 40 times slower than for free CN, with a rate coefficient of (2.0 ± 0.9) × 10(9) M(-1) s(-1) obtained from the rise in the HCN product v1(C═N stretch) IR absorption band. Evidence is also presented for CN complexes with acetone that are more strongly bound than the CN-CDCl3 complexes because of CN interactions with the carbonyl group. The rates of reactions of these more strongly associated radicals are slower still.

Improving accessibility to lung transplantation for children through air transport.

INTRODUCTION: There are a limited number of pediatric lung transplant programs in the United States; therefore, geographical barriers limit critically ill children who may be good candidates for lung transplantation. MATERIALS AND METHODS: With advancements in technology, extracorporeal membrane oxygenation (ECMO) is becoming an option to bridge children requiring advanced life support to lung transplantation and offers the opportunity to transport critically ill children to pediatric lung transplant centers. RESULTS: Air transport services with rotor-wing and fixed-wing aircraft were successfully developed and quickly became as a vital component of our pediatric lung transplant program offering ECMO for both transport and as a bridge to lung transplantation to children throughout the United States. CONCLUSION: Air transport services can be an important component of pediatric lung transplant programs to offer this advanced treatment to children.

Dynamics of photodissociation of XeF2 in organic solvents.

Transient electronic absorption measurements with 1 ps time resolution follow XeF2 photoproducts in acetonitrile and chlorinated solvents. Ultraviolet light near 266 nm promptly breaks one Xe-F bond, and probe light covering 320-700 nm monitors the products. Some of the cleaved F atoms remain in close proximity to an XeF fragment and perturb the electronic states of XeF. The time evolution of a perturbed spectral feature is used to monitor the FXe-F complex population, which decays in less than 5 ps. Decay can occur through geminate recombination, diffusive separation or reaction of the complex with the solvent.

Direct and indirect hydrogen abstraction in Cl + alkene reactions.

Reactions between Cl atoms and propene can lead to HCl formation either by direct H abstraction or through a chloropropyl addition complex. Barring stabilizing collisions, the chloropropyl radical will either decompose to reactants or form HCl and allyl products. Using velocity-map imaging to measure the quantum state and velocity of the HCl products provides a view into the reaction dynamics, which show signs of both direct and indirect reaction mechanisms. Simulated trajectories of the reaction highlight the role of the direct H-abstraction pathways, and the resultant simulated scattering images show reasonable agreement with measurement. The simulations also show the importance of large excursions of the Cl atom far from equilibrium geometries within the chloropropyl complex, and these large-amplitude motions are the ultimate drivers toward HCl + allyl fragmentation. Gas-phase measurements of larger alkenes, 2-methylpropene and 2,3-dimethylbut-2-ene, show slightly different product distributions but still feature similar reaction dynamics. The current suite of experiments offers ready extensions to liquid-phase bimolecular reactions.

Extracorporeal membrane oxygenation and retransplantation in lung transplantation: an analysis of the UNOS registry.

BACKGROUND: Despite limited organ availability, extracorporeal membrane oxygenation (ECMO) and retransplantation are becoming more commonplace. METHODS: Using the United Network for Organ Sharing (UNOS) database, we evaluated survival of patients treated with ECMO before lung transplantation and undergoing retransplantation. A query identified cadaveric recipients from 2001 to 2012 over the age of 6 years. RESULTS: Of 15,772 lung recipients, 15 583 never received ECMO, whereas 189 did. Mean age was 52.1 ± 14.4 versus 46.8 ± 16.5 years for non-ECMO and ECMO groups, respectively (p < 0.0001). Using Kaplan-Meier method, there were survival differences between ECMO and non-ECMO groups (p < 0.0001) and first-time transplants with and without ECMO to retransplants with and without ECMO (p < 0.0001). The proportional hazards model identified higher risk with ECMO use in idiopathic pulmonary fibrosis (hazard ratio [HR] 1.09; 95 % confidence interval (CI), 1.02-1.17; p = 0.014) and retransplants (HR 1.77; 95 % CI, 1.55-2.03; p < 0.0001). CONCLUSIONS: Survival for retransplantation was similar to ECMO as a primary option with significant mortality associated with ECMO use in patients with idiopathic pulmonary fibrosis and retransplants.

Tracheostomy in adolescent patients bridged to lung transplantation with ambulatory venovenous extracorporeal membrane oxygenation.

Venovenous extracorporeal membrane oxygenation (VV-ECMO) is quickly becoming a method to bridge patients with advanced pulmonary disease to lung transplantation. Historically, pediatric hospitals have more in-depth experience with the use of ECMO; however, bridging children with this method of respiratory support to lung transplantation is carried out infrequently with limited reported experiences in the medical literature. This article describes the optimal use of ambulatory VV-ECMO in two adolescent patients who were bridged to lung transplantation aided by tracheostomy placement.

Bloodless pediatric cardiopulmonary bypass for a 3.2-kg patient whose parents are of Jehovah's Witness faith.

Patients and parents of Jehovah's Witness (JW) faith present multiple challenges to a medical team, especially in the neonatal and pediatric population. The medical team must balance honoring the parents' request of not receiving blood products and fulfilling our commitment as advocates for the child's wellbeing. A multidisciplinary approach to cardiac surgery must be embraced for bloodless cardiopulmonary bypass (CPB) to be successful. At our institution, we have developed strategies and techniques for blood conservation that are used preoperatively, intraoperatively, and postoperatively for every CPB case with the goal of a bloodless procedure. These protocols include: preoperative erythropoietin, preoperative iron administration, selection of a CPB circuit specific to the patient's height and weight, acute normovolemic hemodilution, retrograde autologous prime and venous autologous prime, tranexamic acid administration, zero-balance ultrafiltration, flushing of the pump suckers post-CPB, modified ultrafiltration, and cell salvage. We present an 8-day-old, 3.2-kg patient of JW faith with aortic valve stenosis and regurgitation and a patent foramen ovale who underwent a bloodless left ventricle-to-aorta tunnel repair and aortic valve repair on CPB.

Comparison of routine laboratory measures of heparin anticoagulation for neonates on extracorporeal membrane oxygenation.

Our objective was to determine the best measure of heparin anticoagulation in neonatal patients on extracorporeal membrane oxygenation. Activated clotting time (ACT), activated partial thromboplastin time (aPTT), and antifactor Xa levels, along with corresponding heparin infusion rates and heparin bolus volumes, were collected from neonates receiving ECMO at our institution from 2008 to 2013. After natural log transformation of antifactor Xa, ACT, and aPTT, overall correlations between antifactor Xa levels and either ACT or aPTT and correlations between these tests and heparin infusion rates were evaluated using linear mixed models that accounted for both within- and between-patient correlations. Twenty-six neonates with an average weight of 3.4 kg (standard deviation .7) had a total of 27 separate ECMO runs during the study period. Within each patient, ACT (r = .40, p < .0001) and aPTT (r = .48, p < .0001) were both directly correlated with antifactor Xa levels. In contrast, between patients, only aPTT maintained a direct correlation with antifactor Xa (r = .61, p = .07), whereas ACT showed a statistically significant inverse correlation with antifactor Xa (r = -.48, p = .04). Compared with ACT, aPTT is more consistently reflective of the anticoagulation status both within each patient on ECMO and between patients treated with ECMO. Future efforts to develop standardized heparin infusion algorithms for patients on ECMO should consider using aPTT levels to monitor anticoagulation.