Cannabis Use Disorder in Adolescents.

With increasing cannabis potency, increasing variety of methods of cannabis use, and lower perceived risk of cannabis use, it is increasingly important clinicians who work with adolescents remain up-to-date on the latest literature regarding cannabis use and its associated outcomes. Adolescent cannabis use is associated with chronic cognitive, psychosocial, psychiatric, and physical outcomes. Clinicians working in this field should be able to recognize cannabis use disorder, understand how adolescent cannabis use can impact the developing mind, and have informed discussions with patients and families regarding risks of use.

ADHD symptoms and smoking outcomes in a randomized controlled trial of varenicline for adolescent and young adult tobacco cessation.

BACKGROUND: Most adult daily smokers try their first cigarette during adolescence. Attention-Deficit Hyperactivity Disorder (ADHD) in adolescents is associated with increased risk for cigarette smoking. The impact of ADHD symptoms on smoking cessation among adolescents has been less well-studied. The present secondary data analysis from a clinical trial of varenicline examined ADHD symptoms as a moderator of smoking cessation in adolescents and young adults. METHODS: The double-blind, placebo-controlled trial included treatment-seeking daily cigarette smokers ages 14 - 21 (N = 157) randomized to receive a 12-week course of varenicline or placebo, added to weekly smoking cessation counseling. At pre-treatment assessment, participants were administered a self-report measure of ADHD symptoms, the ADHD - Rating Scale (ADHD-RS). High (≥5) versus low (<5) and continuous ADHD-RS symptom counts in both hyperactive/impulsive (HI) and inattention (IA) domains were examined as predictors of smoking outcomes. RESULTS: Participants with high IA symptoms at baseline were less likely to achieve 7-day point prevalence abstinence (PPA) at weekly visits (p = .001) during active treatment and end-of-treatment (p = .002) compared to those with low IA symptoms. In contrast, high HI symptoms did not predict differences in 7-day PPA or end-of-treatment abstinence versus low symptoms (p's ≥ .07). These findings were not modified by varenicline versus placebo treatment assignment. CONCLUSIONS: ADHD IA symptoms were associated with poorer cessation outcomes among adolescent smokers. These findings warrant additional investigation into how ADHD symptoms may be accounted for in smoking cessation interventions for adolescents and young adults.

Cannabis Use Disorder in Adolescents.

With increasing cannabis potency, increasing variety of methods of cannabis use, and lower perceived risk of cannabis use, it is increasingly important clinicians who work with adolescents remain up-to-date on the latest literature regarding cannabis use and its associated outcomes. Adolescent cannabis use is associated with chronic cognitive, psychosocial, psychiatric, and physical outcomes. Clinicians working in this field should be able to recognize cannabis use disorder, understand how adolescent cannabis use can impact the developing mind, and have informed discussions with patients and families regarding risks of use.

The role of halogen bonding in metal free phosphors.

The enhanced spin-orbit coupling necessary for phosphorescence is thought to be due to the halogen bonding that is present in the all-organic crystalline systems. To elucidate the underlying mechanism, the electronic and optical properties of purely organic phosphor candidates are investigated using density functional theory calculations. The unit cell structure of a known organic phosphor containing bromine is used to validate the accuracy of the computational methodology. Compared to experiments, the calculated lattice constants deviate by less than 1 percent for each lattice constant. The same computational approach is then used to predict the lattice constants for molecular analogs containing fluorine, chlorine, and iodine. Electronic structure and photonic properties of the predicted crystals are computed. Finally, the presence of halogen bonding is corroborated, with fluorine forming the weakest and iodine the strongest halogen bonding interactions. Our findings demonstrate how computational methods can be effectively used for the predictive design of organic materials in lighting devices.

Conjugated Copolymers That Shouldn't Be.

Multiple studies have explored using cage silsesquioxanes (SQs) as backbone elements in hybrid polymers motivated by their well-defined structures and physical and mechanical properties. As part of this general exploration, we report unexpected photophysical properties of copolymers derived from divinyl double decker (DD) SQs, [vinyl(Me)Si(O0.5 )2 ][PhSiO1.5 ]8 [(O0.5 )2 Si(Me)vinyl] (vinylDDvinyl). These copolymers exhibit strong emission red-shifts relative to model compounds, implying unconventional conjugation, despite vinyl(Me)Si(O-)2 siloxane bridges. In an effort to identify minimum SQ structures that do/do not offer extended conjugation, we explored Heck catalyzed co-polymerization of vinyl-ladder(LL)-vinyl compounds, vinyl(Me/Ph)Si(O0.5 )2 [PhSiO1.5 ]4 (O0.5 )2 Si(Me/Ph)vinyl, with Br-Ar-Br. Most surprising, the resulting oligomers show 30-60 nm emission red-shifts beyond those seen with vinylDDvinyl analogs despite lacking a true cage. Further evidence for unconventional conjugation includes apparent integer charge transfer (ICT) between LL-co-thiophene, bithiophene, and thienothiophene with 10 mol % F4 TCNQ, suggesting potential as p-type doped organic/inorganic semiconductors.

Substitutional 4d transition metal doping in atomically thin lead.

To study the potential of plumbene as a dilute magnetic semiconductor, we computationally investigate the structural, electronic, and magnetic properties of 4d transition metal (TM) doped plumbene using density functional theory (DFT). These calculations show that Zr, Nb, Mo, Tc-doped plumbene systems are magnetic while no magnetic solution was found for Y, Ru, Rh, and Pd-doped cases. We also calculate the magnetic couplings between two TM impurities in the system with an impurity concentration of less than 2%. Strong exchange couplings and large magnetic anisotropic energies, indicate the potential for spintronics applications.

Magnetic properties of 3d transition metal (Sc-Ni) doped plumbene.

Recently, a synthesized two-dimensional layer structured material, so-called "plumbene", has attracted research interests because of its sizeable spin-orbit coupling. To study the potential of this material as a dilute magnetic semiconductor, we computationally investigate the structure, electronic, and magnetic properties of 3d transition metal (TM) doped plumbene using density functional theory (DFT). These calculations show that Ti, V, Cr, Mn, Fe, and Co-doped plumbene systems are magnetic while no magnetic solution was found for Sc and Ni. We also calculate the magnetic couplings between two TM impurities in the system with an impurity concentration of less than 2%. For V, Mn, Fe, Co-doped systems with short inter-impurity distances, we obtain a Curie temperature above room temperature using the mean-field approximation, indicating the potential for magnetic storage and spintronics applications.

Design principles for the energy level tuning in donor/acceptor conjugated polymers.

To identify reliable molecular design principles for energy level tuning in donor/acceptor conjugated polymers (CPs), we studied the governing factors by means of ab initio calculations based on density-functional theory (DFT). We investigated a series of CPs in which we independently and systematically varied the electron withdrawing power of the acceptor unit and the electron donating power of the donor unit, while maintaining the same conjugated chain conformation. We observed that the introduction of a stronger acceptor unit, while keeping the same donor unit in the CP, lowers the LUMO level, but leaves the HOMO level almost unchanged. Conversely, enhancing the strength of the donor unit for the same acceptor unit raises the HOMO level, while maintaining the LUMO level. We identified strong correlations between the frontier orbital energy levels and the degree of orbital localization, which depends on the electron donating or withdrawing power of the molecular groups carrying the orbitals. Moreover, the HOMO/LUMO gap of the CP is directly proportional to the charge transfer between donating and accepting units, which provides a robust design criterion for CPs.