The introduction of three-way catalytic converter (TWC) to meet stringent vehicular NO emission standards worldwide has led to an unintended consequence of vehicle-derived ammonia (NH) emission, which might degrade air quality and affect human health, especially in urban areas. The nitrogen stable isotope composition of NH (δN-NH) may be a useful tool to trace NH sources, but the isotopic signature of vehicle-emitted NH is lacking. Here we report the δN-NH measured from tailpipe exhausts collected directly from 19 different vehicles equipped with TWC using "grab" sample technique optimized to avoid isotopic fractionation. We found a large of range of NH concentration (from 1 to 37 ppm, x̄ ± 1σ = 10 ± 8 ppm) and δN value (from -38.1 ‰ to 49.0 ‰, x̄ ± 1σ = 1.2 ± 20.9 ‰) for our samples (n = 57). Our results indicate a correlation between δN-NH and NH concentrations (i.e. δN-NH (‰) = 16.9(± 2.2)In(NH concentration; ppm) - 31.7(± 4.7) (R = 0.53, P < 0.01) that is associated with the catalyst temperature, which is generally agree with the results of theoretical calculation. After consideration of the vehicle emission evolution, dominant driving condition and tunnel δN-NH variation, a representative δN-NH value (mean) of vehicle source is identified as 0.8000, which is distinct from (larger than) other NH volatilization-related emission sources. Using our newly measured δN values and Bayesian mixing model, we approximate the overall contribution of vehicles to ambient NH before, during, and after an international event in Beijing was 14.1 %, 7.9 %, and 21.5 %, respectively, which agree well with the course of traffic restriction. Collectively, our findings demonstrate the importance of using vehicle-emitted δN-NH to quantify vehicular NH contribution in urban atmospheres.
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http://dx.doi.org/10.1016/j.scitotenv.2024.177415 | DOI Listing |
J Hand Surg Am
January 2025
Department of Orthopaedic Surgery, Washington University School of Medicine, Saint Louis, MO. Electronic address:
Purpose: Isolated coronal shear fractures of the distal humerus in adolescents are rare injuries with unique surgical challenges. Respect for the posterior blood supply, open physes, and need for direct visualization to achieve anatomic reduction are critical considerations in surgical fixation. This study presents a case series and a surgical approach used in treating these patients.
View Article and Find Full Text PDFThe objective of this systematic literature review was to investigate the effect of Coca-Cola on the properties and, more generally, on the integrity of direct dental filling materials. In addition, it aimed to highlight the importance of dietary behaviour in dentistry and, in this context, to identify tangible strategies for action in routine clinical practice. An electronic search was conducted between January 2022 and July 2024.
View Article and Find Full Text PDFJ Korean Neurosurg Soc
January 2025
Department of Neurosurgery, Bucheon St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
Objective: Clazosentan is a recently approved endothelin receptor antagonist indicated for the prevention of vasospasm and related complications following aneurysmal subarachnoid hemorrhage (aSAH). To date, no direct, head-to-head comparison between clazosentan and nimodipine has been conducted. In this study, we indirectly assessed the efficacy and safety of these two drugs in preventing vasospasm and its associated outcomes after aSAH.
View Article and Find Full Text PDFJ Glob Antimicrob Resist
January 2025
Microbiology Unit, Clinical Pathology Department, Piacenza General Hospital, Piacenza, Italy; Medicine and Surgery Department, University of Parma, Parma, Italy.
Objectives: Infections by Carbapenem-Resistant Enterobacterales in hospitals represent a severe threat but little is known on outbreaks in rehabilitation wards caused by Klebsiella pneumoniae producing Klebsiella pneumoniae Carbapenemase (KPC-Kp). We report an outbreak by KPC-Kp, in a Neurorehabilitation Unit in Italy, analysed through Whole-Genome Sequencing (WGS) for transmission routes reconstruction to improve management of KPC-Kp infections in rehabilitation units.
Methods: We investigated cases and KPC-Kp isolates collected from February to October 2022 from hospital surveillance.
J Vasc Surg Venous Lymphat Disord
January 2025
Department of Vascular Surgery, Chenzhou First People's Hospital and the First Affiliated, Hospital of Xiangnan University, Chenzhou, Hunan Province 423000, China. Electronic address:
Objective: This study sought to investigate the changes in plasma D-dimer levels during catheter-directed thrombolysis (CDT) in patients with acute lower extremity deep venous thrombosis (DVT), analyze imaging results, and assess their clinical implications.
Methods: We retrospectively analyzed 62 patients diagnosed with acute lower extremity DVT who underwent CDT between March 2019 and December 2022. Plasma D-dimer levels were measured before CDT, at regular intervals after CDT, and at the end of CDT.
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