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Towards Autonomous Experiments by Connecting High Performance Microscopy with High Performance Computing
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Yrast structures of Nb98 and Mo99
Get PDFBackground: Neutron-rich nuclei in the A≈100 mass region are interesting due to a rapid shape transition, especially pronounced in the Zr isotopes, and more recently observed in Nb isotopes. Nb98, with only one proton and one neutron outside the subshell closure nucleus of Zr96, is amenable to shell model calculations. Purpose: To further examine the rapid shape transition, the yrast structure of Nb98 was established in this work. This was the only yrast structure missing from all immediate neighbors to Zr96. Method: The yrast structure of Nb98 was studied in the fission of the compound systems formed in three heavy-ion induced reactions, Mg24 (134.5 MeV) +Yb173, Na23 (129 MeV) +Yb176, and O18 (91 MeV) +Pb208. Prompt γ-ray spectroscopy was accomplished using the Gammasphere array. Results: Excitation energies up to 3 MeV were observed for the first time in Nb98. The yrast structure above the previously known (5)+ isomer was established. In the process of studying Nb98 the yrast structure of positive-parity states in Mo99 was extended to 3.7 MeV excitation energy, the previously known Nb99 level scheme was enriched, and two new levels were added in the level scheme of Zr97. Conclusions: The coupling of the odd proton occupying the g9/2 orbital to the yrast states in the core nucleus of Zr97 can account for all observed states in Nb98. The yrast structure for the positive-parity states of Mo99 is compared to the deformed ground-state bands of the Ru101 isotone and of Mo98,100
Challenges Are Present, But California Transit Agencies Are Open to Open-loop
Get PDFOpen-loop fare payment systems are an emerging technology that allows customers to pay with credit cards, debit cards, smartphone applications, and digital wallets when boarding transit vehicles or entering platform areas. The California Integrated Travel Program (Cal-ITP) aims to foster the implementation of open-loop payments among California’s transit agencies. What do transit agencies have to say about this goal and the challenges it might pose for them and their travelers? Researchers from the University of California, Davis gathered surveys from a small sample of transit agencies (N = 21) and found that agencies are interested in open-loop payments, agencies and passengers would likely support it, but that it also presents challenges for agencies and passengers. This policy brief summarizes the findings from that research and provides policy implications. View the NCST Project Webpag
Hybrid versus vaccine immunity of mRNA-1273 among people living with HIV in East and Southern Africa: a prospective cohort analysis from the multicentre CoVPN 3008 (Ubuntu) study.
Get PDFBACKGROUND: With limited access to mRNA COVID-19 vaccines in lower income countries, and people living with HIV (PLWH) largely excluded from clinical trials, Part A of the multicentre CoVPN 3008 (Ubuntu) study aimed to assess the safety of mRNA-1273, the relative effectiveness of hybrid versus vaccine immunity, and SARS-CoV-2 viral persistence among PLWH in East and Southern Africa during the omicron outbreak. METHODS: Previously unvaccinated adults with HIV and/or other comorbidities associated with severe COVID-19 received either one (hybrid immunity) or two (vaccine immunity) 100-mcg doses of ancestral strain mRNA-1273 in the first month, depending on baseline evidence of prior SARS-CoV-2 infection. In a prospective cohort study design, we used covariate-adjusted Cox regression and counterfactual cumulative incidence methods to determine the hazard ratio and relative risk of COVID-19 and severe COVID-19 with hybrid versus vaccine immunity within six months. The ongoing Ubuntu study is registered on ClinicalTrials.gov (NCT05168813) and this work was conducted from December 2021 to March 2023. FINDINGS: Between December 2021 and September 2022, 14,237 participants enrolled, and 14,002 (83% PLWH, 69% SARS-CoV-2 seropositive) were included in the analyses. Vaccinations were safe and well tolerated. Common adverse events were pain or tenderness at the injection site (26.7%), headache (20.4%), and malaise (20.3%). Severe adverse events were rare (0.8% of participants after the first and 1.1% after the second vaccination), and none were life-threatening or fatal. Among PLWH, the median CD4 count was 635 cells/μl and 18.5% had HIV viraemia. The six-month cumulative incidences in the hybrid immunity and vaccine immunity groups were 2.02% (95% confidence interval [CI] 1.61-2.44) and 3.40% (95% CI 2.30-4.49) for COVID-19, and 0.048% (95% CI 0.00-0.10) and 0.32% (95% CI 0.59-0.63) for severe COVID-19. Among all PLWH the hybrid immunity group had a 42% lower hazard rate of COVID-19 (hazard ratio [HR] 0.58; 95% CI 0.44-0.77; p < 0.001) and a 73% lower hazard rate of severe COVID-19 (HR 0.27; 95% CI 0.07-1.04; p = 0.056) than the vaccine immunity group, but this effect was not seen among PLWH with CD4 counts <350 cells/μl or HIV viraemia. Twenty PLWH had persistent SARS-CoV-2 virus at least 50 days. INTERPRETATION: Hybrid immunity was associated with superior protection from COVID-19 compared to vaccine immunity with the ancestral mRNA-1273 vaccine. Persistent infections among immunocompromised PLWH may provide reservoirs for emerging variants. FUNDING: National Institute of Allergy and Infectious Diseases
Ab Initio Rotational and Vibrational Spectroscopy of C3H5 Radicals at the Coupled Cluster Level.
Get PDFCombustion and pyrolysis processes of allene and propyne are known to involve radicals with the structural formula C3H5, the most stable of which is the classic resonance-stabilized allyl radical. In addition to allyl, four other isomers of C3H5 are possible: the propene derivatives Z-1-propenyl, E-1-propenyl, and 2-propenyl, as well as the cyclopropane derivative cyclopropyl. Among these 5 species, the allyl radical has been extensively studied both theoretically and spectroscopically; however, little is known about the spectroscopy of the cyclopropyl radical, and virtually no experimental spectroscopic data are available for the remaining three. Here, we carry out an ab initio investigation of the C3H5 radicals at the coupled cluster level of theory with a focus on computing the spectroscopic parameters relevant for pure rotational and rotationally resolved vibrational spectroscopy. The rotational constants, dipole moments, spin-spin tensors, and Fermi contact parameters are evaluated at the CCSD(T)/cc-pwCVQZ level of theory, while vibrational properties such as vibration-rotation interaction parameters and centrifugal distortion constants are calculated at the frozen-core CCSD(T)/ANO1 level. Vibrational analysis was carried out using second-order vibrational perturbation theory with an explicit treatment of resonances. Finally, the inversion tunneling potential in cyclopropyl as well as the methyl internal rotation potentials in the 1- and 2-propenyl isomers are computed and relevant spectroscopic parameters for modeling their resultant tunneling splittings are derived. Results from the calculations compare favorably with the extensive body of spectroscopic literature on the allyl radical, giving confidence that the computed parameters for the remaining isomers will be useful for guiding the interpretation of future high-resolution experimental spectroscopy of these radicals
Caregiver Global Impression Observations from EMBARK: A Phase 3 Study Evaluating Delandistrogene Moxeparvovec in Ambulatory Patients with Duchenne Muscular Dystrophy.
Get PDFINTRODUCTION: Duchenne muscular dystrophy (DMD) is a rare, progressive, debilitating neuromuscular disease. The early childhood onset and debilitating nature of the disease necessitate decades of caretaking for most patients. Caregivers have a critical role in evaluating patients physical functioning and/or response to treatment. Using DMD-specific caregiver-reported scales, the impact of delandistrogene moxeparvovec gene therapy on caregivers perceived change in patient disease status or severity was evaluated using the Caregiver Global Impression of Change and Severity (CaGI-C and CaGI-S, respectively). METHODS: In the Phase 3 randomized, double-blind, placebo-controlled trial (EMBARK; NCT05096221), the CaGI-C at week 52 and change from baseline to week 52 in CaGI-S were evaluated in a post hoc analysis. The CaGI-C assesses caregivers impressions of change in DMD symptoms, physical ability, ability to perform daily activities, and overall health. The CaGI-S evaluates current severity of DMD symptoms, physical ability, ability to perform activities of daily living, and overall health. Data were evaluated using multi-domain responder index (MDRI) and ordinal regression analyses. RESULTS: MDRI analyses across all four CaGI-C items yielded a treatment difference of 1.7 (95% confidence interval [CI]: 0.90-2.5) favoring delandistrogene moxeparvovec; a treatment difference of 1.1 (95% CI 0.30-1.9) was observed for the CaGI-S favoring delandistrogene moxeparvovec. After adjusting for age, ordinal regression analysis showed a nominally significant increase in the odds of achieving a better rating for delandistrogene moxeparvovec-treated patients on all four CaGI-C items (≥ 3.8-fold increase). After adjusting for baseline severity and age, ordinal regression analysis showed a nominally significant increase in the odds of improvement on all four CaGI-S items (≥ 2.2-fold increase). CONCLUSION: These exploratory findings captured by caregiver-reported outcomes add to the totality of evidence that supports the clinical benefits of delandistrogene moxeparvovec for patients with DMD. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov identifier, NCT05096221
Chronic Nitrous Oxide Toxicity Despite Elevated Serum Vitamin B12 Level
Get PDFIntroduction: Nitrous oxide (N2O) toxicity is an uncommon but important-to-recognize presentation of neurologic deficits and hematologic abnormalities, which may never resolve in some patients. In the United States, nitrous oxide is legal to possess and easily obtainable for purchase in stores and online. Nitrous oxide abuse and its long-term sequelae must be recognized by the emergency physician to ensure proper follow-up and maximize neurologic outcomes.
Case Report: A 28-year-old male with past medical history of alcoholism and polysubstance abuse presented to the emergency department with progressive paresthesias, shortness of breath, and neurologic complaints following daily inhalation of N2O for three weeks. He was diagnosed with N2O toxicity due to functional vitamin B12deficiency in the setting of elevated B12 levels from prophylactic self-supplementation.
Conclusion: While most recreational users of nitrous oxide will experience transient neurologic symptoms resolving within minutes of cessation, frequent or heavy users may develop permanent neurotoxicity. Exposed patients require close follow-up with neurology and vitamin B12 supplementation to maximize neurologic recovery. In this patient, there was persistence of neurologic symptoms over 24 hours after cessation of use despite self-supplementation of vitamin B12
