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Introduction: Congenital vertebral malformations are common developmental abnormalities in screw-tailed brachycephalic dog breeds. Subsequent vertebral instability and/or vertebral canal stenosis caused by these malformations can lead to spinal cord compression manifesting in pain, paraparesis, ataxia and/or paralysis. Various methods for spinal stabilization are in common use. However, these are without significant risk due to narrow margins of surgical error and variable vertebral anatomy. We evaluate a novel method for spinal stabilization where a custom 3D-printed plate is created and surgically fitted to the patient's spine using custom 3D-printed drill guides., Objective: To describe the surgical technique and short-term outcomes in patients treated with custom 3D-printed plates and drill guides., Method: A retrospective analysis of 11 dogs from two referral hospitals which underwent this procedure was undertaken. Post-operative CT scans were assessed for spinal canal screw perforation using the modified Zdichavsky classification. Pre-operative and post-operative neurological status were assessed using the Modified Frankel Scale and the surgical technique including post-operative imaging and recovery findings were described., Results: Optimal screw placement (grade I) was achieved in 63% of placed screws across the eleven dogs. Partial penetration of the medial wall (grade IIa) was observed in 3% of screws and partial penetration of the lateral wall (grade IIIa) was observed in 29% of screws. Full penetration of the lateral pedicle wall (grade IIIb) was observed in 5% of screws and no screws fully penetrated the medial vertebral wall (grade IIb)., Discussion: We demonstrated that custom 3D-printed drill guides and titanium plates can provide a safe peri-operative alternative for surgical spinal stabilization of dogs with vertebral column instability due to congenital vertebral malformations. Further research is needed to describe long-term outcomes of this surgical technique on patient health., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Guirguis, Asanovic, Beggs and Long.)

Due to the threats posed by many volatile organic compounds (VOCs) to human health in indoor spaces via air, the mass transfer characteristics of VOCs are of critical importance to the study of their mechanism and control. As a significant part of the mass transfer process, diffusion widely exists in emissions from floors (e.g., PVC floors) and in sorption in porous materials. Molecular simulation studies by can provide unparalleled insights into the molecular mechanisms of VOCs. We construct the detailed atomistic structures of PVC blend membranes to investigate the diffusion behavior of VOC molecules (n-hexane) in PVC by molecular dynamics (MD). The variation in the diffusion coefficient of n-hexane in PVC with respect to temperature is in line with Arrhenius' law. The effect of temperature on the diffusion mechanism was investigated from the perspectives of free volume, cavity distribution and polymer chain mobility. It was found that the relationships between the diffusion coefficients of n-hexane in the polymer and the inverse fractional free volume are exponential and agree well with the free volume theory. Hopefully, this study will offer quantitative insights into the mass transport phenomena of VOCs within polymeric materials.

Adolescent COVID-19 vaccination has stalled at 53% in the United States. Vaccinating adolescents remains critical to preventing the continued transmission of COVID-19, the emergence of variants, and rare but serious disease in children, and it is the best preventive measure available to return to in-person schooling. We investigated parent-adolescent COVID-19 vaccine decision-making. Between 24 February and 15 March 2021, we conducted surveys and 12 focus groups with 46 parent-adolescent dyads in Southern California. Parents and adolescents completed a survey prior to participation in a focus group discussion, which focused on exploring COVID-19 vaccine acceptance or uncertainty and was guided by the 5C vaccine hesitancy model. Parents uncertain about vaccinating adolescents expressed low vaccine confidence and high COVID-19 disease risk complacency. Parents who accepted COVID-19 vaccination for adolescents expressed high confidence in health authority vaccine recommendations, high perceived COVID-19 risk, and collective responsibility to vaccinate children. Additionally, unique pandemic-related factors of vaccine acceptance included vaccinating for emotional health, resuming social activities, and vaccine mandates. Among parents, 46% were willing to vaccinate their adolescent, 11% were not, and 43% were unsure. Among adolescents, 63% were willing to vaccinate. Despite vaccine availability, 47% of adolescents remain unvaccinated against COVID-19. Factors associated with vaccine uncertainty and acceptability inform health care practitioner, school, community, and public health messaging to reach parents and adolescents.