Endocannabinoids and related lipids linked to social exclusion in individuals with chronic non-medical prescription opioid use.

Opioid-related overdose deaths are still on the rise in North America, emphasizing the need to better understand the underlying neurobiological mechanisms regarding the development of opioid use disorder (OUD). Recent evidence from preclinical and clinical studies indicate that the endocannabinoid system (ECS) may play a crucial role in stress and reward, both involved in the development and maintenance of substance use disorders. Animal models demonstrate a specific crosstalk between the ECS and the endogenous opioid system. However, translational studies in humans are scarce. Here, we investigated basal plasma levels of the endocannabinoids anandamide (AEA) and 2-arachidonoyglycerol (2-AG), and eight endocannabinoid-related lipids, including oleoylethanolamide (OEA) and palmitoylethanolamide (PEA), as well as whole blood fatty acid amide hydrolase (FAAH) activity in chronic non-medical prescription opioid users (NMPOU; n = 21) compared to opioid-naïve healthy controls (n = 29) considering age, sex, and cannabis use as potential confounders. Additionally, the association of endocannabinoids and related lipids with the participants' response to experimentally induced social exclusion was examined. We found significantly elevated basal AEA, OEA, and PEA levels in NMPOU compared to controls, but no differences in FAAH activity, 2-AG, or other endocannabinoid-related lipids. Within NMPOU, higher AEA levels were associated with lower perception of social exclusion. Robust positive correlations within N-acylethanolamines (i.e., AEA, OEA, and PEA) indicate strong metabolic associations. Together with our recent findings of elevated basal 2-AG levels in dependent cocaine users, present results indicate substance-specific alterations of the ECS that may have implications in the search for novel therapeutic interventions for these populations

Hydrogen in amorphous and microcrystalline silicon films prepared by hydrogen dilution

Hydrogen incorporation in silicon layers prepared by plasma-enhanced chemical-vapor deposition using silane dilution by hydrogen has been studied by infrared spectroscopy ͑IR͒ and elastic recoil detection analysis ͑ERDA͒. The large range of silane dilution investigated can be divided into an amorphous and a microcrystalline zone. These two zones are separated by a narrow transition zone at a dilution level of 7.5%; here, the structure of the material cannot be clearly identified. The films in/near the amorphous/microcrystalline transition zone show a considerably enhanced hydrogen incorporation. Moreover, comparison of IR and ERDA and film stress measurements suggests that these layers contain a substantial amount of molecular hydrogen probably trapped in microvoids. In this particular case the determination of the total H content by IR spectroscopy leads to substantial errors. At silane concentrations below 6%, the hydrogen content decreases sharply and the material becomes progressively microcrystalline. The features observed in the IR-absorption modes can be clearly assigned to mono-and/or dihydride bonds on ͑100͒ and ͑111͒ surfaces in silicon crystallites. The measurements presented here constitute a further indication for the validity of the proportionality constant of Shanks et al. ͓Phys. Status Solidi B 110, 43 ͑1980͔͒, generally used to estimate the hydrogen content in ''conventional'' amorphous silicon films from IR spectroscopy; additionally, they indicate that this proportionality constant is also valid for the microcrystalline samples

Device grade microcrystalline silicon owing to reduced oxygen contamination

As-deposited undoped microcrystalline silicon (µc-Si:H) has in general a pronounced n-type behavior. Such a material is therefore often not appropriate for use in devices, such as p-i-n diodes, as an active, absorbing i layer or as channel material for thin-film transistors. In recent work, on p-i-n solar cells, this disturbing n-type character had been successfully compensated by the ``microdoping'' technique. In the present letter, it is shown that this n-type behavior is mainly linked to oxygen impurities; therefore, one can replace the technologically delicate microdoping technique by a purification method, that is much easier to handle. This results in a reduction of oxygen impurities by two orders of magnitude; it has, furthermore a pronounced impact on the electrical properties of µc-Si:H films and on device performance, as well. Additionally, these results prove that the unwanted donor-like states within µc-Si:H are mainly due to extrinsic impurities and not to structural native defects