Interactions of protective behavioral strategies and cannabis use motives: An online survey among past-month users

Given the constant high prevalence of cannabis use and cannabis dependence, it is important to determine protective behaviors on the individual level, which buffer the effects of risk factors. Protective Behavioral Strategies for Marijuana (PBSM) have been identified to play an important role for harm reduction in adolescent and young adult users. In the present study, we analyzed if PBSM moderate the effects of use motives (captured by the Marijuana Motives Measure, MMM) on the severity of dependence beyond the effects of age, gender, education and cannabis use frequency. We used confirmatory factor analysis (CFA) to validate the German versions of PBSM and MMM. Data was gathered in an online survey distributed to randomly chosen households in the city of Bern in the German speaking part of Switzerland. The final sample comprised 362 past-month users. Results showed negative correlations between PBSM and cannabis use frequency and severity of dependence. The only motives being correlated with severity of dependence were coping and routine, beyond frequency of use. PBSM significantly moderated the effect only of routine motives on the severity of dependence. However, only a few cases who used PBSM extensively were affected. PBSM appear to be an important factor to reduce harm among past-month users but not among those with dependent use patterns, e.g. coping and routine users. Clinical implications are discussed. The routine factor adds significantly to the MMM and should be implemented and improved in future studies. PBSM as well as the MMM can be used in future studies in German speaking populations

Versatile Confocal Raman Imaging Microscope Built from Off-the-Shelf Opto-Mechanical Components

Confocal Raman microscopic (CRM) imaging has evolved to become a key tool for spatially resolved, compositional analysis and imaging, down to the μm-scale, and nowadays one may choose between numerous commercial instruments. That notwithstanding, situations may arise which exclude the use of a commercial instrument, e.g., if the analysis involves toxic or radioactive samples/environments; one may not wish to render an expensive instrument unusable for other uses, due to contamination. Therefore, custom-designed CRM instrumentation—being adaptable to hazardous conditions and providing operational flexibility—may be beneficial. Here, we describe a CRM setup, which is constructed nearly in its entirety from off-the-shelf optomechanical and optical components. The original aim was to develop a CRM suitable for the investigation of samples exposed to tritium. For increased flexibility, the CRM system incorporates optical fiber coupling to both the Raman excitation laser and the spectrometer. Lateral raster scans and axial profiling of samples are facilitated by the use of a motorized xyz-translation assembly. Besides the description of the construction and alignment of the CRM system, we also provide (i) the experimental evaluation of system performance (such as, e.g., spatial resolution) and (ii) examples of Raman raster maps and axial profiles of selected thin-film samples (such as, e.g., graphene sheets)

Cannabis use, attitudes, regulation and health: Survey data from an urban population of users and non-users

Background: Although illegal in most countries, cannabis remains the most common illicit drug in Switzerland and worldwide. While there is growing evidence on adverse effects of cannabis use, most users do not report any problems or negative consequences. In the face of a sustained high prevalence of cannabis use and the recent legalization waves in different parts of the world, it is important to know how cannabis is perceived in the general population and how current users regulate their own use. The present study aims to investigate users’ and non-users’ attitudes towards cannabis regulations and towards current users. Additionally, self-rated health measures as well as protective behavioral strategies and other cannabis related variables were assessed. Design and Method: We collected data from 380 current users and 659 non-users who were recruited by invitation letter or online media platforms. The data was analyzed using basic descriptive statistical procedures. Results: Results revealed that both groups favor moderate cannabis regulation measures over prohibition and no regulation at all. On average, they report the same subjective health. Protective strategies are often used and are associated with better health and lower severity of dependence in cannabis users. Conclusions: Taken together, results indicate that safe use of cannabis is possible for most users, while there is a group of users at risk of 15-20 %, which may benefit from control by regulatory measures

First observation of tritium adsorption on graphene

In this work, we report on the first-ever studies of graphene exposed to tritium gas in a controlled environment. The single layer graphene on $\textrm{SiO}_2$/Si substrate was exposed to 400 mbar of $\textrm{T}_2$ for a total time of ~55 h. The resistivity of the graphene sample was measured in-situ during tritium exposure using the Van der Pauw method. After the exposure, the samples were scanned with a confocal Raman microscope to study the effect of tritium on the graphene structure as well as the homogeneity of spectral modifications. We found that the sheet resistance increases by three orders of magnitude during the exposure. By Raman microscopy, we demonstrate that the graphene film can withstand the bombardment from the beta-decay of tritium, and primary and secondary ions. Additionally, the Raman spectra after tritium exposure are comparable with previously observed results in hydrogen-loading experiments carried out by other groups. By thermal annealing we could demonstrate, using Raman spectral analysis, that the structural changes were partially reversible. Considering all observations, we conclude that the graphene film was at least partially tritiated during the tritium exposure.Comment: Submitted to Nanoscale Advances (RSC), 14 pages, 4 figure

Calibration strategy and status of tritium purity monitoring for KATRIN

<p> </p> <p>The KATRIN (Karlsruhe Tritium Neutrino) experiment aims to measure the mass of the electron anti-neutrino with a sensitivity of 200 meV/<em>c</em>2 by measuring the spectrum of the beta electrons close to the kinematic endpoint region. For monitoring the isotopic composition in the gaseous tritium source a custom-made Laser-Raman-System (LARA) has been developed at the Tritium Laboratory Karlsruhe.</p> <p>The two approaches used to calibrate the LARA system for trueness <3 % are: i) theoretical intensities together with a spectral intensity standard and ii) highly accurate gas mixtures. Latest efforts have improved the in-situ calibration via spectral standard with re-calculated theoretical uncertainties and uncertainty analysis. Recently, the TRIHYDE experiment has been setup which enables cross-checking of the calibration via gas mixtures of all six hydrogen isotopologues and further studies of systematic effects.</p> <p>This poster presents the benefits and status of both complementary approaches.</p

Versatile Confocal Raman Imaging Microscope Built from Off-the-Shelf Opto-Mechanical Components

Confocal Raman microscopic (CRM) imaging has evolved to become a key tool for spatially resolved, compositional analysis and imaging, down to the &mu;m-scale, and nowadays one may choose between numerous commercial instruments. That notwithstanding, situations may arise which exclude the use of a commercial instrument, e.g., if the analysis involves toxic or radioactive samples/environments; one may not wish to render an expensive instrument unusable for other uses, due to contamination. Therefore, custom-designed CRM instrumentation&mdash;being adaptable to hazardous conditions and providing operational flexibility&mdash;may be beneficial. Here, we describe a CRM setup, which is constructed nearly in its entirety from off-the-shelf optomechanical and optical components. The original aim was to develop a CRM suitable for the investigation of samples exposed to tritium. For increased flexibility, the CRM system incorporates optical fiber coupling to both the Raman excitation laser and the spectrometer. Lateral raster scans and axial profiling of samples are facilitated by the use of a motorized xyz-translation assembly. Besides the description of the construction and alignment of the CRM system, we also provide (i) the experimental evaluation of system performance (such as, e.g., spatial resolution) and (ii) examples of Raman raster maps and axial profiles of selected thin-film samples (such as, e.g., graphene sheets)

Accurate Reference Gas Mixtures Containing Tritiated Molecules: Their Production and Raman-Based Analysis

Highly accurate, quantitative analyses of mixtures of hydrogen isotopologues—both the stable species, H2, D2, and HD, and the radioactive species, T2, HT, and DT—are of great importance in fields as diverse as deuterium–tritium fusion, neutrino mass measurements using tritium β-decay, or for photonuclear experiments in which hydrogen–deuterium targets are used. In this publication we describe a production, handling, and analysis facility capable of fabricating well-defined gas samples, which may contain any of the stable and radioactive hydrogen isotopologues, with sub-percent accuracy for the relative species concentrations. The production is based on precise manometric gas mixing of H2, D2, and T2. The heteronuclear isotopologues HD, HT, and DT are generated via controlled, in-line catalytic reaction or by β-induced self-equilibration, respectively. The analysis was carried out using an in-line intensity- and wavelength-calibrated Raman spectroscopy system. This allows for continuous monitoring of the composition of the circulating gas during the self-equilibration or catalytic evolution phases. During all procedures, effects, such as exchange reactions with wall materials, were considered with care. Together with measurement statistics, these and other systematic effects were included in the determination of composition uncertainties of the generated reference gas samples. Measurement and calibration accuracy at the level of 1% was achieved.Peer Reviewe

First operation of the KATRIN experiment with tritium

The determination of the neutrino mass is one of the major challenges in astroparticle physics today. Direct neutrino mass experiments, based solely on the kinematics of β β -decay, provide a largely model-independent probe to the neutrino mass scale. The Karlsruhe Tritium Neutrino (KATRIN) experiment is designed to directly measure the effective electron antineutrino mass with a sensitivity of 0.2 eV 0.2 eV (90% 90% CL). In this work we report on the first operation of KATRIN with tritium which took place in 2018. During this commissioning phase of the tritium circulation system, excellent agreement of the theoretical prediction with the recorded spectra was found and stable conditions over a time period of 13 days could be established. These results are an essential prerequisite for the subsequent neutrino mass measurements with KATRIN in 2019

Quantitative Long-Term Monitoring of the Circulating Gases in the KATRIN Experiment Using Raman Spectroscopy.

The Karlsruhe Tritium Neutrino (KATRIN) experiment aims at measuring the effective electron neutrino mass with a sensitivity of 0.2 eV/c2, i.e., improving on previous measurements by an order of magnitude. Neutrino mass data taking with KATRIN commenced in early 2019, and after only a few weeks of data recording, analysis of these data showed the success of KATRIN, improving on the known neutrino mass limit by a factor of about two. This success very much could be ascribed to the fact that most of the system components met, or even surpassed, the required specifications during long-term operation. Here, we report on the performance of the laser Raman (LARA) monitoring system which provides continuous high-precision information on the gas composition injected into the experiment's windowless gaseous tritium source (WGTS), specifically on its isotopic purity of tritium-one of the key parameters required in the derivation of the electron neutrino mass. The concentrations cx for all six hydrogen isotopologues were monitored simultaneously, with a measurement precision for individual components of the order 10-3 or better throughout the complete KATRIN data taking campaigns to date. From these, the tritium purity, εT, is derived with precision of &lt;10-3 and trueness of &lt;3 × 10-3, being within and surpassing the actual requirements for KATRIN, respectively