Direct measurement of brake and tire wear particles based on real-world driving conditions

With implementing vehicle emission control policies, tailpipe particulate emissions have been gradually controlled, and the relative contribution of non-tailpipe particulate emissions, such as brake and tire wear, has further increased. A unified and scientific method for sampling non-tailpipe particulate matter (PM) emissions is essential to improve the accuracy of the emission characteristics and factors. This study proposes a novel sampling method based on real-world driving conditions to obtain information on emissions and extract characteristic conditions for tire and brake pad wear. We extracted 200 representative braking segments for simulation experiments based on road type, initial and final velocities, temperature, and deceleration rate. Two standard test cycles to simulate the tire wear conditions of the front and rear wheels were constructed based on velocity, lateral, and vertical forces. Under the real-world driving condition test cycle, the emission factors of PM2.5 and PM10 for brake wear particles of passenger vehicles were 2.66 mg/km and 11.65 mg/km, respectively. In contrast, the emission factors of PM2.5 and PM10 for tire wear particles were 0.21 mg/km and 1.27 mg/km, respectively. Moreover, this study provides insights and basic data for localizing and improving the emission model, which can enhance its applicability and accuracy.

Emission factors of ammonia for on-road vehicles in urban areas from a tunnel study in south China with laser-absorption based measurements

Vehicle emission is an important source of ammonia (NH₃) in urban areas. To better address the role of vehicle emission in urban NH₃ sources, the emission factor of NH₃ (NH₃-EF) from vehicles running on roads under real-world conditions (on-road vehicles) needs to update accordingly with the increasingly tightened vehicle emission standards. In this study, laser-absorption based measurements of NH₃ were conducted during a six-day campaign in 2019 at a busy urban tunnel with a daily traffic flow of nearly 40,000 vehicles in south China's Pearl River Delta (PRD) region. The NH₃-EF was measured to be 16.6 ± 6.3 mg km^-1 for the on-road vehicle fleets and 19.0 ± 7.2 mg km^-1 for non-electric vehicles, with an NH₃ to CO₂ ratio of 0.27 ± 0.09 ppbv ppmv^-1. Multiple linear regression revealed that the average NH₃-EFs for gasoline vehicles (GVs), liquefied petroleum gas vehicles, and heavy-duty diesel vehicles (HDVs) were 18.8, 15.6, and 44.2 mg km^-1, respectively. While NH₃ emissions from GVs were greatly reduced with enhanced performance of engines and catalytic devices to meet stricter emission standards, the application of urea selective catalytic reduction (SCR) in HDVs makes their NH₃ emission an emerging concern. Based on results from this study, HDVs may contribute over 11% of the vehicular NH₃ emissions, although they only share ∼4% by vehicle numbers in China. With the updated NH₃-EFs, NH₃ emission from on-road vehicles was estimated to be 9 Gg yr^-1 in the PRD region in 2019, contributing only 5% of total NH₃ emissions in the region, but still might be a dominant NH₃ source in the urban centers with little agricultural activity.

Real-World Efficacy and Safety of Lenvatinib in Korean Patients with Advanced Hepatocellular Carcinoma: A Multicenter Retrospective Analysis

INTRODUCTION/OBJECTIVE

Lenvatinib demonstrated efficacy and safety in patients with advanced hepatocellular carcinoma (HCC) in the randomized phase III REFLECT trial. Considering the discrepancies in patients between clinical trial data and daily practice, an account of practical experience is needed.

METHODS

We conducted a multicenter retrospective analysis in which 3 tertiary referral centers participated. A total of 92 patients with advanced HCC treated with lenvatinib between September 2018 and January 2020 were analyzed.

RESULTS

Lenvatinib was used as the first-line therapy for 67 (72.8%) patients, and for 25 (27.2%) patients previously treated with other systemic therapy including immune checkpoint inhibitors. At the time of initiation of lenvatinib, 74 (80.4%) and 18 (19.6%) patients were classified as Child-Pugh A and B, respectively. Thirty-five patients (38.0%) had extensive disease that would have excluded them from the REFLECT trial. In the Child-Pugh A group, the response rate graded according to the Response Evaluation Criteria in Solid Tumors v1.1 was 21.1%, median progression-free survival (PFS) was 4.6 (95% confidence interval [CI] 3.1-6.1) months, and overall survival (OS) was 10.7 (95% CI 4.8-16.5) months for patients treated with first-line lenvatinib (n = 57). With second- or later-line lenvatinib (n = 17), median PFS and OS were 4.1 (95% CI 3.1-5.1) and 6.4 (95% CI 5.1-7.7) months, respectively. In the Child-Pugh B group (n = 18), median PFS and OS were 2.6 (95% CI 0.6-4.6) and 5.3 (95% CI 2.0-8.5) months, respectively. The most common grade 3-4 toxicities were hyperbilirubinemia (n = 8; 8.7%), AST elevation (n = 6; 6.5%), and diarrhea (n = 5; 5.4%) across all study patients.

CONCLUSIONS

In this real-world study, lenvatinib was found to be well tolerated and effective in more heterogeneous HCC patient populations.