Inclination of polarized illumination increases symmetry of structures grown via inorganic phototropism.

Inclination of unpatterned, linearly polarized illumination in the plane of the electric field oscillation effected increased directional feature alignment and decreased off-axis order in Se-Te deposits generated by inorganic phototropic growth relative to that produced using normal incidence. Optically based growth simulations reproduced the experimental results indicating a photonic basis for the morphology change. Modeling of the light scattering at the growth interface revealed that illumination inclination enhances scattering that localizes the optical field along the polarization plane and suppresses cooperativity in defect-driven scattering. Thus, the symmetry of the deposited structures increased as the asymmetry of the illumination increased, as measured by the inclination of the illumination incidence away from the surface normal.

Associations of alternative cannabis product use and poly-use with subsequent illicit drug use initiation during adolescence.

RATIONALE: Specific cannabis products may differentially increase risk of initiating non-cannabis illicit drug use during adolescence. OBJECTIVE: To determine whether ever- and poly-use of smoked, vaporized, edible, concentrate, or blunt cannabis products are associated with subsequent initiation of non-cannabis illicit drug use. METHODS: High school students from Los Angeles completed in-classroom surveys. The analytic sample (N = 2163; 53.9% female; 43.5% Hispanic/Latino; baseline M age = 17.1 years) included students who reported never using illicit drugs at baseline (spring, 11th grade) and provided data at follow-up (fall and spring, 12th grade). Logistic regression models assessed associations between use of smoked, vaporized, edible, concentrate, and blunt cannabis at baseline (yes/no for each product) and any non-cannabis illicit drug use initiation-including cocaine, methamphetamine, psychedelics, ecstasy, heroin, prescription opioids, or benzodiazepines-at follow-up. RESULTS: Among those who never used non-cannabis illicit drugs at baseline, ever cannabis use varied by cannabis product (smoked = 25.8%, edible = 17.5%, vaporized = 8.4%, concentrates = 3.9%, and blunts = 18.2%) and patterns of use (single product use = 8.2% and poly-product use = 21.8%). After adjustment for baseline covariates, odds of illicit drug use at follow-up were largest for baseline ever users of concentrates (aOR [95% CI] = 5.74[3.16-10.43]), followed by vaporized (aOR [95% CI] = 3.11 [2.41-4.01]), edibles (aOR [95% CI] = 3.43 [2.32-5.08]), blunts (aOR [95% CI] = 2.66[1.60-4.41]), and smoked (aOR [95% CI] = 2.57 [1.64-4.02]) cannabis. Ever use of a single product (aOR [95% CI] = 2.34 [1.26-4.34]) or 2 + products (aOR [95% CI] = 3.82 [2.73-5.35]) were also associated with greater odds of illicit drug initiation. CONCLUSIONS: For each of five different cannabis products, cannabis use was associated with greater odds of subsequent illicit drug use initiation, especially for cannabis concentrate and poly-product use.

The effects of the 4/20 cannabis holiday and adult-use cannabis legalization on medical cannabis sales and medical cannabis patient registration in Arizona.

BACKGROUND: This study examined whether the 4/20 cannabis holiday was associated with increases in medical cannabis sales from licensed dispensaries in Arizona from 2018-2021, and whether adult-use cannabis legalization (the vote in November 2020 and retail sales in January 2021) was associated with declines in medical cannabis sales and in the number of registered medical patients. METHODS: Data came from the Arizona Medical Marijuana Program monthly reports from January 2018-December 2021. The reports show daily sales from licensed medical cannabis dispensaries (i.e., the number of medical cannabis dispensary transactions and the amount of cannabis sold in pounds), which we averaged by week, and show the number of registered medical cannabis patients each month. Autoregressive integrated moving average models were used to test changes in these outcomes associated with the 4/20 cannabis holiday and with legalization of adult-use cannabis. RESULTS: During the week of the 4/20 cannabis holiday, medical cannabis dispensary transactions abruptly increased by an average of 2,319.4 transactions each day (95% CI: 1636.1, 3002.7), and the amount of medical cannabis sold increased by an average of 120.3 pounds each day (95% CI: 99.3-141.3). During the first week of adult-use cannabis sales in late January 2021, medical cannabis dispensary transactions abruptly decreased by an average of 5,073 transactions each day (95% CI: -5,929.5, -4216.7), and the amount of medical cannabis sold decreased by an average of 119.1 pounds each day (95% CI: -144.2, -94.0). Moreover, medical cannabis sales continued to gradually decline each week after the start of adult-use retail sales, with declines in sales preceding declines in registered patients. By December 2021, slightly over a year after the vote to legalize adult-use cannabis, the actual number of registered medical cannabis patients fell short of the forecasted number, had adult-use not been legalized, by 36.5%. Moreover, the number of medical dispensary transactions and the amount of medical cannabis sold fell short of expectations, had adult-use cannabis not been legalized, by 58% and 53%, respectively. CONCLUSIONS: Findings document the blurred boundary between medical and non-medical cannabis use and are consistent with the possibility that medical cannabis legalization contributes to increases in adult cannabis use and dependence.

Preparedness for healthy ageing and polysubstance use in long-term cannabis users: a population-representative longitudinal study.

BACKGROUND: Cannabis is often characterised as a young person's drug. However, people who began consuming cannabis in the 1970s and 1980s are no longer young and some have consumed it for many years. This study tested the preregistered hypothesis that long-term cannabis users show accelerated biological ageing in midlife and poorer health preparedness, financial preparedness, and social preparedness for old age. METHODS: In this longitudinal study, participants comprised a population-representative cohort of 1037 individuals born in Dunedin, New Zealand, between April, 1972, and March, 1973, and followed to age 45 years. Cannabis, tobacco, and alcohol use and dependence were assessed at ages 18 years, 21 years, 26 years, 32 years, 38 years, and 45 years. Biological ageing and health, financial, and social preparedness for old age were assessed at age 45 years. Long-term cannabis users were compared using independent samples t tests with five groups: lifelong cannabis non-users, long-term tobacco users, long-term alcohol users, midlife recreational cannabis users, and cannabis quitters. In addition, regression analyses tested dose-response associations for continuously measured persistence of cannabis dependence from age 18 years to 45 years, with associations adjusted for sex, childhood socioeconomic status, childhood IQ, low childhood self-control, family substance dependence history, and persistence of alcohol, tobacco, and other illicit drug dependence. FINDINGS: Of 997 cohort members still alive at age 45 years, 938 (94%) were assessed at age 45 years. Long-term cannabis users showed statistically significant accelerated biological ageing and were less equipped to manage a range of later-life health, financial, and social demands than non-users. Standardised mean differences between long-term cannabis users and non-users were large: 0·70 (95% CI 0·46 to 0·94; p<0·0001) for biological ageing, -0·72 (-0·96 to -0·49, p<0·0001) for health preparedness, -1·08 (-1·31 to -0·85; p<0·0001) for financial preparedness, and -0·59 (-0·84 to -0·34, p<0·0001) for social preparedness. Long-term cannabis users did not fare better than long-term tobacco or alcohol users. Tests of dose-response associations suggested that cannabis associations could not be explained by the socioeconomic origins, childhood IQ, childhood self-control, and family substance-dependence history of long-term cannabis users. Statistical adjustment for long-term tobacco, alcohol, and other illicit drug dependence suggested that long-term cannabis users' tendency toward polysubstance dependence accounted for their accelerated biological ageing and poor financial and health preparedness, although not for their poor social preparedness (ß -0·10, 95% CI -0·18 to -0·02; p=0·017). INTERPRETATION: Long-term cannabis users are underprepared for the demands of old age. Although long-term cannabis use appears detrimental, the greatest challenge to healthy ageing is not use of any specific substance, but rather the long-term polysubstance use that characterises many long-term cannabis users. Substance-use interventions should include practical strategies for improving health and building financial and social capital for healthy longevity. FUNDING: The National Institute on Aging and the UK Medical Research Council. The Dunedin Research Unit is supported by the New Zealand Health Research Council and the New Zealand Ministry of Business, Innovation and Employment.

Diminished Structural Brain Integrity in Long-term Cannabis Users Reflects a History of Polysubstance Use.

BACKGROUND: Cannabis legalization and use are outpacing our understanding of its long-term effects on brain and behavior, which is fundamental for effective policy and health practices. Existing studies are limited by small samples, cross-sectional measures, failure to separate long-term from recreational use, and inadequate control for other substance use. Here, we address these limitations by determining the structural brain integrity of long-term cannabis users in the Dunedin Study, a longitudinal investigation of a population-representative birth cohort followed to midlife. METHODS: We leveraged prospective measures of cannabis, alcohol, tobacco, and other illicit drug use in addition to structural neuroimaging in 875 study members at age 45 to test for differences in both global and regional gray and white matter integrity between long-term cannabis users and lifelong nonusers. We additionally tested for dose-response associations between continuous measures of cannabis use and brain structure, including careful adjustments for use of other substances. RESULTS: Long-term cannabis users had a thinner cortex, smaller subcortical gray matter volumes, and higher machine learning-predicted brain age than nonusers. However, these differences in structural brain integrity were explained by the propensity of long-term cannabis users to engage in polysubstance use, especially with alcohol and tobacco. CONCLUSIONS: These findings suggest that diminished midlife structural brain integrity in long-term cannabis users reflects a broader pattern of polysubstance use, underlining the importance of understanding comorbid substance use in efforts to curb the negative effects of cannabis on brain and behavior as well as establish more effective policy and health practices.

Plastic Morphological Response to Spectral Shifts during Inorganic Phototropic Growth.

Plants exhibit phototropism in which growth is directed toward sunlight and demonstrate morphological plasticity in response to changes in the spectral distribution of the incident illumination. Inorganic phototropic growth via template-free, light-directed electrochemical deposition of semiconductor material can spontaneously generate highly ordered mesostructures with anisotropic, nanoscale lamellar features that exhibit a pitch proportional to the wavelength (λ) of the stimulating illumination. In this work, Se-Te films were generated via a two-step inorganic phototropic growth process using a series of narrowband light-emitting diode sources with discrete output wavelengths (λ0 ≠ λ1). Analogous to the plasticity observed in plants, changes in illumination wavelength from λ0 to λ1 resulted in morphological changes including feature branching, termination, and/or fusion along the growth direction. The interfacial feature pitch changed with the growth duration, in some cases in a notably nonmonotonic fashion, and eventually matched that obtained for growth using only λ1. Simulated morphologies generated by modeling light-material interactions at the growth interface closely matched the evolved structures observed experimentally, indicating that the characteristics of the optical stimulation produce the observed plastic response during inorganic phototropic growth. Examination of the interfacial electric field modulation for λ1 illumination of simplified structures, representative of those generated experimentally, revealed the interfacial light scattering and concentration behavior that directed phototropic growth away from equilibrium, as well as the emergent nature of the phenomena that reestablish equilibrium.

The anticipated effects of simultaneous alcohol and cannabis use: Initial development and preliminary validation.

Social learning theories suggest that outcome expectancies are strong determinants of behavior, and studies find that alcohol and cannabis expectancies are associated with negative substance use outcomes. However, there are no measures to date that assess expectancies for simultaneous alcohol and cannabis use (SAM), often referred to as SAM, despite strong links with negative consequences and rising time trends. The present study sought to provide initial validation of test scores for the Anticipated Effects of Simultaneous Alcohol and Cannabis Use Scale (AE-SAM), using a sample of past month college student simultaneous users (N = 434). Exploratory factor analysis and confirmatory factor analysis conducted in random half samples suggested five expectancy factors, representing high arousal positive, high arousal negative (alcohol driven), high arousal negative (cannabis driven), low arousal positive, and low arousal negative expectancies. The factor structure was invariant across sex, race/ethnicity, and simultaneous use frequency, and demonstrated convergent and discriminant validity with other alcohol/cannabis expectancy measures. AE-SAM high arousal positive expectancies were associated with simultaneous use frequency and heavier drinking/cannabis use, AE-SAM high arousal negative (cannabis driven) expectancies were associated with less frequent simultaneous use and more negative alcohol consequences, and AE-SAM low arousal negative expectancies were associated with less cannabis use. Effects of AE-SAM high arousal positive and high arousal negative (cannabis driven) expectancies remained, above and beyond other expectancy measures, suggesting that AE-SAM expectancies provide additional information beyond single substance expectancies. The results demonstrate the feasibility and utility of assessing simultaneous use expectancies, and lay groundwork for future research on simultaneous use expectancies in relation to alcohol and cannabis couse outcomes. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Long-Term Cannabis Use and Cognitive Reserves and Hippocampal Volume in Midlife.

OBJECTIVE: Cannabis use is increasing among midlife and older adults. This study tested the hypotheses that long-term cannabis use is associated with cognitive deficits and smaller hippocampal volume in midlife, which is important because midlife cognitive deficits and smaller hippocampal volume are risk factors for dementia. METHODS: Participants are members of a representative cohort of 1,037 individuals born in Dunedin, New Zealand, in 1972-1973 and followed to age 45, with 94% retention. Cannabis use and dependence were assessed at ages 18, 21, 26, 32, 38, and 45. IQ was assessed at ages 7, 9, 11, and 45. Specific neuropsychological functions and hippocampal volume were assessed at age 45. RESULTS: Long-term cannabis users showed IQ decline from childhood to midlife (mean=-5.5 IQ points), poorer learning and processing speed relative to their childhood IQ, and informant-reported memory and attention problems. These deficits were specific to long-term cannabis users because they were either not present or were smaller among long-term tobacco users, long-term alcohol users, midlife recreational cannabis users, and cannabis quitters. Cognitive deficits among long-term cannabis users could not be explained by persistent tobacco, alcohol, or other illicit drug use, childhood socioeconomic status, low childhood self-control, or family history of substance dependence. Long-term cannabis users showed smaller hippocampal volume, but smaller hippocampal volume did not statistically mediate cannabis-related cognitive deficits. CONCLUSIONS: Long-term cannabis users showed cognitive deficits and smaller hippocampal volume in midlife. Research is needed to ascertain whether long-term cannabis users show elevated rates of dementia in later life.

Validating a brief screening measure for early-onset substance use during adolescence in a diverse, nationwide birth cohort.

The Loeber Risk Score (LRS) was developed to predict early-onset cannabis use in adolescence from late childhood, facilitating early identification. However, the LRS was developed in non-representative historical samples, leaving uncertain its generalizability to children/adolescents across the U.S. today. We externally validated the LRS in a diverse, nationwide cohort (N = 4,898) weighted to the composition of the U.S. Census. Participants in 20 cities completed assessments when youth were approximately 5, 9, and 15 years old. Parents completed the LRS at the age ∼5 and ∼9 interviews. At the age ∼15 interview, youth reported on the onset of alcohol/drug use before age 15, monthly drinking/binge drinking at ages 14-16, and use of cannabis multiple times per month at ages 14-16. First, we validated the LRS measured at age ∼9. Area under the receiver operating curve was 0.62 for onset of cannabis use before age 15, 0.68 for onset of cigarette use before age 15, and 0.62 for use of cannabis multiple times per month at ages 14-16. For drinking outcomes, LRS performance could not be distinguished from chance prediction. The recommended screening cutoff of LRS ≥ 2 identified 24% of children, among whom early-onset cannabis/cigarette use outcomes occurred 1.4-2.2 times more frequently than the general population. The LRS' performance did not vary significantly by sex, race, or ethnicity. When the LRS was measured at age ∼5, AUROC was significantly lower for some outcomes. Together, findings support the LRS measure as a potential tool for identifying children in early or late childhood at risk of early-onset drug use in adolescence.

Selective-Area, Water-Free Atomic Layer Deposition of Metal Oxides on Graphene Defects.

Passivating defective regions on monolayer graphene with metal oxides remains an active area of research for graphene device integration. To effectively passivate these regions, a water-free atomic layer deposition (ALD) recipe was developed and yielded selective-area ALD (sa-ALD) of mixed-metal oxides onto line defects in monolayer graphene. The anisotropically deposited film targeted high-energy defect sites that were formed during synthesis or transfer of the graphene layer. The passivating layer exceeded 10 nm thickness with minimal deposition onto the basal plane of graphene. The mixed-metal oxide film was of comparable quality to films deposited using nonselective water-based ALD methods, as shown by X-ray photoelectron spectroscopy. The development of sa-ALD techniques to target defect regions on the graphene sheet, while keeping the basal plane intact, will provide a new mechanism to passivate graphene defects and modify the electronic and physical properties of graphene.

Are recreational cannabis laws associated with declining medical cannabis program enrollment in the U.S.? An analysis of cardholder enrollment and demographic characteristics from 2013 to 2020.

BACKGROUND: There is speculation that enrollment in U.S. state medical cannabis programs differs depending on whether adult recreational cannabis use is legal. If true, this could have implications for public health and policy. METHODS: Using medical cannabis registry data from U.S. states with a mandatory registry between 2013 and 2020 (N = 23 states), this study examined time-trends in medical cannabis cardholder enrollment and tested whether enrollment trends differed depending on adult recreational cannabis legalization. RESULTS: Multilevel models showed that time-trends for registered active medical cardholders differed during years when adult recreational cannabis use was legal versus not legal (time*recreational cannabis law interaction: b = -0.004, p < 0.01, 95% CI = -0.005, -0.003). The population prevalence of registered active medical cardholders increased over time in years when recreational cannabis was not legal (i.e., medical-only years; b = 0.004, p < 0.001, 95% CI = 0.003, 0.004, corresponding to an increase of 380 cardholders per 100,000 people per year), and decreased in years when recreational cannabis was legal (i.e., recreational years; b = -0.001, p < 0.001, 95% CI = -0.002, -0.001, corresponding to a decrease of 100 cardholders per 100,000 people per year). Time-trends were similar for each sex (male, female) and age group (18-30/35, 30/35+), with each cardholder group showing increases in medical-only years and decreases in recreational years. In medical-only years, there were no differences in enrollment time-trends across sex, but older cardholder (30/35+) enrollment increased at a faster rate than younger cardholder enrollment (18-30/35) (F = 16.199, p < 0.001). In recreational years, male cardholder enrollment decreased at a faster rate than female cardholder enrollment (F = 7.347, p < 0.01), but there was no difference in trends across age. Three states, all with medical-only years, provided data on ethnicity/race. Results showed significant increases from 2016 to 2020 in enrollment of White, African-American, and Hispanic individuals. CONCLUSIONS: Findings suggest that recreational cannabis legalization is associated with decreasing enrollment in medical cannabis programs, particularly for males.

Assessing Effects of Near-Field Synergistic Light Absorption on Ordered Inorganic Phototropic Growth.

We report herein that synergistic light absorption in the optical near-field enables nanoscale self-organization during inorganic phototropic growth. Se-Te was grown electrochemically under illumination from an incoherent, unstructured light source in geometrically constrained, wavelength scale areas. Despite the limited dimensions, with as few as two discrete features produced in a single sub-micron dimension, the deposit morphology exhibited defined order and anisotropy. Computer modeling analysis of light absorption in simulated structures revealed a synergy wherein light capture in a nanoscale feature was enhanced by the presence of additional adjacent features, with the synergistic effect originating predominantly from nearest neighbor contributions. Modeling moreover indicated that synergistic absorption is produced by scattering of the incident illumination by individual nanoscale features, leading to a local increase in the near-field intensity and consequently increasing the absorption in neighboring features. The interplay between these optical processes establishes the basis for spontaneous order generation via inorganic phototropic growth.

Adolescent executive cognitive functioning and trait impulsivity as predictors of young-adult risky drinking and alcohol-related problems.

Executive cognitive functioning (ECF) and trait impulsivity have long been implicated in risky drinking and alcohol-related problems. However, research on these constructs has developed independently. The present study tested whether two subdomains of adolescent ECF (updating and response inhibition) and adolescent trait impulsivity, considered separately and together, predicted young-adult risky drinking and alcohol-related problems. Data came from the Adolescent/Adult Family Development Project-a longitudinal study of the intergenerational transmission of alcohol use. Alcohol-naïve youth ages 11-17 (N = 249) completed three tasks tapping ECF subdomains of updating (letter-number sequencing, matrix span task) and inhibition (immediate memory task) and a self-reported measure of trait impulsivity (UPPS-P). Approximately 7 years later (ages 18-25), participants reported on their drinking behavior (maximum drinks in a day, heavy episodic drinking, alcohol-related problems). We tested whether adolescent ECF and trait impulsivity predicted young-adult drinking outcomes, separately and together. Results showed that poorer adolescent ECF (a latent factor) predicted more maximum drinks in a day (Incidence Rate Ratios [IRR] = 1.27, p = .001) but not young-adult heavy episodic drinking and alcohol-related problems. In contrast, adolescent trait impulsivity predicted all three outcomes: maximum drinks in a day (IRR = 1.34, p < .001), heavy episodic drinking (ß = 0.27, p < .001), and alcohol-related problems in young adulthood (IRR = 1.60, p = .001). Results were similar when adolescent ECF and trait impulsivity were considered together in the same model. Findings suggest that adolescent trait impulsivity is a robust predictor of young-adult risky drinking and alcohol-related problems. Adolescent ECF, and specifically response inhibition, may add predictive value over and above trait impulsivity for some alcohol outcomes. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

The Anticipated Effects of Cannabis Scale (AECS): Initial development and validation of an affect- and valence-based expectancy measure.

Prior research suggests that cannabis expectancies are related to cannabis misuse and problems. Although there are established measures of cannabis expectancies, existing measures have psychometric limitations and/or are lengthy. Existing measures typically have a two-factor structure of positive and negative expectancies, but recent conceptualizations of alcohol expectancies support a valence- (positive vs. negative) and arousal-based (high vs. low arousal) structure. Thus, the present study sought to test a similar structure for cannabis. Cannabis expectancy items underwent 2 preliminary studies, assessing item valance/arousal (n = 233) and relevance to cannabis (n = 124). A final pool of 76 items underwent exploratory factor analysis (n = 303), and remaining items underwent confirmatory factor analysis in a separate sample (n = 469). Lastly, an additional sample (n = 435) examined validity. Results suggested a 3-factor structure (general positive, high arousal negative, low arousal negative) for the 17-item Anticipated Effects of Cannabis Scale (AECS), which was invariant across cannabis use frequency, sex, and race/ethnicity. Positive expectancies were strongly associated with cannabis use, whereas low arousal negative expectancies were protective against cannabis frequency; high arousal negative expectancies were strongly associated with more negative consequences and dependence symptoms. In addition, the proposed interpretation of AECS test scores showed evidence of incremental validity relative to another abbreviated measure. The current study provides initial support for the AECS, a brief, psychometrically sound cannabis expectancies measure. The AECS captures the full range of cannabis effects and may be suited to test discrepancies between cannabis expectancies and subjective response. Additional research is needed to validate its structure and predictive utility. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Cannabis use and psychosocial functioning: evidence from prospective longitudinal studies.

Cannabis legalization is expected to result in more frequent and compulsive use, potentially contributing to worsening psychosocial functioning among some cannabis users. This review evaluates associations between cannabis use and psychosocial functioning in recently published reports from prospective longitudinal studies and considers evidence for and against causation. Unlike previous reviews, studies of adolescents/emerging adults are considered separately from studies that followed adolescents well into adulthood, in part because of vast differences in cumulative cannabis exposure. Infrequent adolescent cannabis use is associated with poorer psychosocial functioning in some domains in emerging adulthood, whereas chronic, frequent adult use, regardless of adolescent-onset versus adult-onset, is associated with poorer psychosocial functioning in many domains. Associations are likely attributable to a combination of causal and non-causal mechanisms, with causal mechanisms likely to be social, not neurotoxic, in nature.

Path-Dependent Morphological Evolution of Se-Te Mesostructures Prepared by Inorganic Phototropic Growth.

We describe herein a path-dependent "history" effect wherein the film morphology generated in the second step of a two-step inorganic phototropic growth process depends on a preexisting structure that has been first grown under different optical stimulation conditions. Se-Te generated with static illumination exhibited a highly anisotropic lamellar morphology with a characteristic feature pitch proportional to the input wavelength. Growth using first a short wavelength of light, followed by growth using a longer wavelength, resulted in the second-stage morphology exhibiting termination of lamellae formed during the first growth step. The lamellar pitch at the end of the second growth step was larger than that effected in the first step. In contrast, use of the same input wavelengths but in the opposite order produced no change in the feature pitch but rather only linear feature extension. Analysis of light absorption in simulated structures, in tandem with the empirical data, indicated that the history effect and asymmetric path dependence are a result of emergent nanophotonic processes at the growth interface that dynamically shape the optical field and direct morphological evolution of the photodeposit in a continuous feedback loop.

A within-person comparison of the subjective effects of higher vs. lower-potency cannabis.

BACKGROUND: Cannabis concentrates have much higher concentrations of THC than marijuana (flower) and are quickly gaining popularity in the United States. One hypothesis is that use of higher-THC cannabis (concentrates) might result in greater intoxication and more severe acute negative effects than lower-THC cannabis (marijuana), but few studies have compared the subjective effects of concentrates and marijuana. METHODS: Current (past-year) cannabis users were recruited online to complete a survey about their cannabis use. Cannabis users who reported using both marijuana and concentrates (n = 574) answered questions about the subjective effects of marijuana and, subsequently, the subjective effects of concentrates. Subjective effects were obtained for the following domains: affect, cognitive function, psychotic-like experiences, physiological effects, and reduced consciousness. RESULTS: Participants reported using marijuana between 5-6 times per week and concentrates slightly more than once per month. Within-person comparisons of the subjective effects of marijuana and concentrates showed that marijuana was rated as producing greater overall positive effects (Marijuana: M = 5.6, Concentrates: M = 4.5; Cohen's d = 0.75, paired t(561) = 14.67, p < .001), including greater positive affect and enhanced cognitive function. Negative effects of both marijuana and concentrates were minimal. Marijuana was selected over concentrates as the 'preferred type' of cannabis by 77.5 % of participants. CONCLUSIONS: The main difference in the subjective effects of marijuana and concentrates is in terms of their positive effects, with marijuana producing greater positive effects than concentrates. Negative effects of marijuana and concentrates were small, suggesting that extreme negative effects are unlikely for regular cannabis users.

Associations between Recent and Cumulative Cannabis Use and Internalizing Problems in Boys from Adolescence to Young Adulthood.

This study tested whether increases in recent and cumulative cannabis use were each associated with increases in internalizing problems from adolescence to young adulthood. Participants were boys from a community sample that was assessed annually from ~age 15-26 (N = 506). Boys reported on their cannabis use, depression symptoms, and anxiety/depression problems each year. Exposures were frequency of cannabis use in a given year (no use, < weekly use, weekly or more frequent use) and cumulative prior years of weekly cannabis use. Outcomes were depression symptoms and anxiety/depression problems in a given year. Analyses examined within-person associations between changes in exposures and outcomes over time, which eliminated "fixed" (unchanging) individual differences as potential confounds. Analyses also accounted for time-varying factors as potential confounds (other substance use, externalizing problems, subclinical psychotic symptoms). Results showed that increases in recent cannabis use and cumulative prior years of weekly cannabis use were each associated with increases in depression symptoms and anxiety/depression problems. After controlling for time-varying covariates, increases in cumulative prior years of weekly cannabis use, but not recent cannabis use, remained associated with increases in depression symptoms and anxiety/depression problems. Specifically, each additional year of prior weekly cannabis use was associated with a small increase in depression symptoms (b = 0.012, p = .005) and anxiety/depression problems (b = 0.009, p = .001). Associations did not vary systematically across time. There was also no evidence of reverse causation. As boys engaged in weekly cannabis use for more years, they showed increases in internalizing problems, suggesting the importance of preventing chronic weekly cannabis use.

Associations between cannabis use and retinal vessel diameter in young adults.

Cannabis appears to have vascular effects that may have implications for cerebrovascular function, but no studies have directly visualized the microvasculature in living cannabis users. The current study used retinal imaging, a tool taken from ophthalmology, to visualize the small retinal microvessels in cannabis users. We compared retinal arteriolar (small arteries) and venular (small veins) diameters in 55 frequent cannabis users and 51 comparison individuals with a mean age of 19.25 years (SD = 2.43). Results indicated that mean arteriolar diameter was statistically significantly wider for cannabis users (M = 157.98, SE = 1.42) than for comparison individuals (M = 153.56, SE = 1.46; F(1,103) = 4.67, p = .033), even after controlling for a variety of covariates and after excluding from analyses cannabis users who had used cannabis in the past 24 h. There was no statistically significant difference in retinal venular diameter between cannabis users and comparison individuals. Findings suggest that frequent cannabis use is associated with wider retinal arterioles, which might represent a residual vasodilatory effect of recent cannabis use or impaired autoregulation resulting from chronic cannabis use. Retinal imaging is a non-invasive, cost-effective tool for visualizing the microvasculature in living individuals and can be combined, in future research, with neuroimaging and other measures of retinal vascular function to better understand the acute and longer-term effects of cannabis use on the microvasculature.

Inorganic Phototropism in Electrodeposition of Se-Te.

Photoelectrochemical deposition of Se-Te on isolated Au islands using an unstructured, incoherent beam of light produces growth of Se-Te alloy toward the direction of the incident light beam. Full-wave electromagnetic simulations of light absorption indicated that the induced spatial growth anisotropy was a function of asymmetric absorption in the evolving deposit. Inorganic phototropic growth is analogous to biological systems such as palm trees that exhibit phototropic growth wherein physical extension of the plant guides the crown toward the time-averaged position of the sun, to maximize solar harvesting.