Mechanistic Rationale for Ketene Formation during Dabbing and Vaping.

Ketene is one of the most toxic vaping emissions identified to date. However, its high reactivity renders it relatively challenging to identify. In addition, certain theoretical studies have shown that realistic vaping temperature settings may betoo low to produce ketene. Each of these issues is addressed herein. First, an isotopically labeled acetate precursor is used for the identification of ketene with enhanced rigor in vaped aerosols. Second, discrepancies between theoretical and experimental findings are explained by accounting for the effects of aerobic (experimental) versus anaerobic (simulated and theoretical) pyrolysis conditions. This finding is also relevant to explaining the relatively low-temperature production of aerosol toxicants beyond ketene. Moreover, the study presented herein shows that ketene formation during vaping is not limited to molecules possessing a phenyl acetate substructure. This means that ketene emission during vaping, including from popular flavorants such as ethyl acetate, may be more prevalent than is currently known.

Vaping Cannabinoid Acetates Leads to Ketene Formation.

Δ8-THC acetate is a relatively new psychoactive cannabis product that is available online and in vape shops across the United States since it is currently largely unregulated. Because it contains a similar substructure to vitamin E acetate, which has been shown to form the poison gas ketene during vaping, we investigated potential ketene formation from Δ8-THC acetate, as well as two other cannabinoids acetates, CBN acetate and CBD acetate, under vaping conditions. Ketene was consistently observed in vaped condensates from all three cannabinoid acetates as well as from a commercial Δ8-THC acetate product purchased online.

The influence of terpenes on the release of volatile organic compounds and active ingredients to cannabis vaping aerosols.

Dabbing and vaping cannabis extracts have gained large popularity in the United States as alternatives to cannabis smoking, but diversity in both available products and consumption habits make it difficult to assess consumer exposure to psychoactive ingredients and potentially harmful components. This work studies the how relative ratios of the two primary components of cannabis extracts, Δ9-tetrahydrocannabinol (THC) and terpenes, affect dosage of these and exposure to harmful or potentially harmful components (HPHCs). THC contains a monoterpene moiety and has been previously shown to emit similar volatile degradation products to terpenes when vaporized. Herein, the major thermal degradation mechanisms for THC and ß-myrcene are elucidated via analysis of their aerosol gas phase products using automated thermal desorption-gas chromatography-mass spectrometry with the aid of isotopic labelling and chemical mechanism modelling. Four abundant products - isoprene, 2-methyl-2-butene, 3-methylcrotonaldehyde, and 3-methyl-1-butene - are shown to derive from a common radical intermediate for both THC and ß-myrcene and these products comprise 18-30% of the aerosol gas phase. The relative levels of these four products are highly correlated with applied power to the e-cigarette, which indicates formation of these products is temperature dependent. Vaping THC-ß-myrcene mixtures with increasing % mass of ß-myrcene is correlated with less degradation of the starting material and a product distribution suggestive of a lower aerosolization temperature. By contrast, dabbing THC-ß-myrcene mixtures with increasing % mass of ß-myrcene is associated with higher levels of HPHCs, and isotopic labelling showed this is due to increased reactivity of ß-myrcene relative to THC.

Design and evaluation of a stand-up motorized prone cart.

BACKGROUND/OBJECTIVE: Prone carts are used for mobility by individuals with spinal cord injury in whom seated mobility (wheelchair) is contraindicated due to ischial or sacral pressure ulcers. Currently available prone carts are uncomfortable, subjecting the user to neck and shoulder strain, and make social interaction and performing activities of daily living difficult. A better design of prone carts is needed. In addition, standing devices have shown some medical benefits. The objective was to design and evaluate an improved prone cart that facilitates standing. DESIGN: Engineering development project with user feedback through questionnaire. Users selected by convenience sampling. METHODS: A marketing survey was performed of nurse managers of spinal cord injury units. Then 2 prototype carts were designed and built. These carts are able to tilt up to 45 degrees and have a joystick-controlled motor for propulsion and other design features, including a workspace storage shelf and rearview mirrors. The carts were evaluated by both patients and caregivers at 2 Veteran's Administration hospitals. OUTCOME MEASURES: Questionnaire of subjects, both patients and caregivers, who used the cart. FINDINGS: Both patients and caregivers liked the carts and the ability to assume a nonhorizontal body angle. The major complaint about the cart was that it seemed too long when it came to making turns. CONCLUSION: This prone cart design is an improvement over the standard, flat variety. However, further design changes will be necessary. This study provided valuable information that will be useful in the next-generation prone cart design project.

Iterative design and evaluation of new prone carts for individuals with SCDs: a technical note.

This paper summarizes a series of projects funded since 1992 to address the compelling need to improve the quality of life for persons with spinal cord dysfunctions who use prone carts. Specifically, Veterans Services Organization, National Institute on Disability and Rehabilitation Research (NIDRR), and the VA Rehabilitation Research and Development funded studies to develop new consumer-driven designs for prone carts. Using an iterative approach, this team of clinicians and designers (1) evaluated existing prone carts; (2) designed a new manual prone cart; (3) designed a new motorized prone cart, including a standing model; and (4) are collaborating with manufacturers to market and commercialize the new prone carts. Prototypes were developed at the Milwaukee Institute of Art and Design with the assistance of Ortho-Kinetics, Inc., and Everest & Jennings and were clinically evaluated at two Veterans Affairs Medical Centers (Tampa and Milwaukee) with patients and caregivers and for compliance with applicable ISO (International Organization for Standardization) for electric wheelchair standards.