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The emissions of marine diesel engines have gained both global and regional attentions because of their impact on human health and climate change. To reduce ship emissions, the International Maritime Organization capped the fuel sulfur content of marine fuels. Consequently, either low-sulfur fuels or additional exhaust gas cleaning devices for the reduction in sulfur dioxide (SO2) emissions became mandatory. Although a wet scrubber reduces the amount of SO2 significantly, there is still a need to consider the reduction in particle emissions directly. We present data on the particle removal efficiency of a scrubber regarding particle number and mass concentration with different marine fuel types, marine gas oil, and two heavy fuel oils (HFOs). An open-loop sulfur scrubber was installed in the exhaust line of a marine diesel test engine. Fine particulate matter was comprehensively characterized in terms of its physical and chemical properties. The wet scrubber led up to a 40% reduction in particle number, whereas a reduction in particle mass emissions was not generally determined. We observed a shift in the size distribution by the scrubber to larger particle diameters when the engine was operated on conventional HFOs. The reduction in particle number concentrations and shift in particle size were caused by the coagulation of soot particles and formation/growing of sulfur-containing particles. Combining the scrubber with a wet electrostatic precipitator as an additional abatement system showed a reduction in particle number and mass emission factors by >98%. Therefore, the application of a wet scrubber for the after-treatment of marine fuel oil combustion will reduce SO2 emissions, but it does not substantially affect the number and mass concentration of respirable particulate matters. To reduce particle emission, the scrubber should be combined with additional abatement systems.

BACKGROUND: Secondary organic aerosols (SOAs) formed from anthropogenic or biogenic gaseous precursors in the atmosphere substantially contribute to the ambient fine particulate matter [PM ≤2.5μm in aerodynamic diameter (PM2.5)] burden, which has been associated with adverse human health effects. However, there is only limited evidence on their differential toxicological impact. OBJECTIVES: We aimed to discriminate toxicological effects of aerosols generated by atmospheric aging on combustion soot particles (SPs) of gaseous biogenic (β-pinene) or anthropogenic (naphthalene) precursors in two different lung cell models exposed at the air-liquid interface (ALI). METHODS: Mono- or cocultures of lung epithelial cells (A549) and endothelial cells (EA.hy926) were exposed at the ALI for 4 h to different aerosol concentrations of a photochemically aged mixture of primary combustion SP and β-pinene (SOAβPIN-SP) or naphthalene (SOANAP-SP). The internally mixed soot/SOA particles were comprehensively characterized in terms of their physical and chemical properties. We conducted toxicity tests to determine cytotoxicity, intracellular oxidative stress, primary and secondary genotoxicity, as well as inflammatory and angiogenic effects. RESULTS: We observed considerable toxicity-related outcomes in cells treated with either SOA type. Greater adverse effects were measured for SOANAP-SP compared with SOAβPIN-SP in both cell models, whereas the nano-sized soot cores alone showed only minor effects. At the functional level, we found that SOANAP-SP augmented the secretion of malondialdehyde and interleukin-8 and may have induced the activation of endothelial cells in the coculture system. This activation was confirmed by comet assay, suggesting secondary genotoxicity and greater angiogenic potential. Chemical characterization of PM revealed distinct qualitative differences in the composition of the two secondary aerosol types. DISCUSSION: In this study using A549 and EA.hy926 cells exposed at ALI, SOA compounds had greater toxicity than primary SPs. Photochemical aging of naphthalene was associated with the formation of more oxidized, more aromatic SOAs with a higher oxidative potential and toxicity compared with β-pinene. Thus, we conclude that the influence of atmospheric chemistry on the chemical PM composition plays a crucial role for the adverse health outcome of emissions. https://doi.org/10.1289/EHP9413.

The United States Medical Licensing Examination (USMLE) Step 1 examination will transition from graded to pass/fail scoring starting no earlier than January 2022. Orthopedic surgery residency programs will need to adapt to these changes. The goal of this study was to investigate the perceptions of orthopedic surgery residency program directors on the change of Step 1 from a graded to a pass/fail examination. We also investigated how the change would affect the other factors that are typically considered in the selection of orthopedic surgery residents. A survey was distributed to 161 directors of allopathic orthopedic surgery programs. Contact information was obtained from a national database. Of those contacted, 75 (46.6%) program directors responded. Most (85.3%) did not support the pass/fail change. Most believe that greater importance will be placed on the Step 2 Clinical Knowledge examination (96.0%), audition elective with their department (84.0%), personal knowledge of the applicant (78.7%), grades (74.7%), letters of recommendation from recognizable orthopedic surgeons (74.7%), and Alpha Omega Alpha status (69.3%). Most also believe that this change will advantage allopathic students who attend highly regarded schools (58.7%). Most of the program directors support a graded preclinical curriculum (69.3%) and caps on the number of orthopedic surgery residency applications (70.7%). Although most orthopedic surgery program directors disagree with the change to a pass/fail Step 1 examination, residency programs will need to reevaluate how they screen applicants for an interview once the scored Step 1 is no longer available. With this change, other factors, such as Step 2 score, audition rotations, and grades in clerkships, will be emphasized more heavily. [ Orthopedics . 2022;45(1):e30–e34.]

United States Medical Licensing Examination Step 1 will transition from numeric grading to pass/fail, sometime after January 2022. The aim of this study was to compare how program directors in orthopaedics and internal medicine perceive a pass/fail Step 1 will impact the residency application process.A 27-item survey was distributed through REDCap to 161 U.S. orthopaedic residency program directors and 548 U.S. internal medicine residency program directors. Program director emails were obtained from the American Medical Association's Fellowship and Residency Electronic Interactive Database.We received 58 (36.0%) orthopaedic and 125 (22.8%) internal medicine program director responses. The majority of both groups disagree with the change to pass/fail, and felt that the decision was not transparent. Both groups believe that the Step 2 Clinical Knowledge exam and clerkship grades will take on more importance. Compared to internal medicine PDs, orthopaedic PDs were significantly more likely to emphasize research, letters of recommendation from known faculty, Alpha Omega Alpha membership, leadership/extracurricular activities, audition elective rotations, and personal knowledge of the applicant. Both groups believe that allopathic students from less prestigious medical schools, osteopathic students, and international medical graduates will be disadvantaged. Orthopaedic and internal medicine program directors agree that medical schools should adopt a graded pre-clinical curriculum, and that there should be a cap on the number of residency applications a student can submit.Orthopaedic and internal medicine program directors disagree with the change of Step 1 to pass/fail. They also believe that this transition will make the match process more difficult, and disadvantage students from less highly-regarded medical schools. Both groups will rely more heavily on the Step 2 clinical knowledge exam score, but orthopaedics will place more importance on research, letters of recommendation, Alpha Omega Alpha membership, leadership/extracurricular activities, personal knowledge of the applicant, and audition electives.

Coloration plays a crucial role in the social communication and survival of organisms. Multidisciplinary studies have been conducted to elucidate the correlation between coloration and melanin biosynthesis (referred as melanogenesis). The multi-copper enzyme tyrosinase catalyzes the first two steps of melanogenesis for coloration in teleosts. Due to the increasing demand of tyrosinase inhibitors for the production of skin whitening cosmetics, hypopigmentation pharmaceuticals, and anti-browning agents, a large number of natural and synthetic inhibitors have been developed over the past few decades. Although a number of previous studies have focused on human use and toxicity, such as the increased cytotoxic effects of ROS-generating compounds, their ecotoxicological impacts on aquatic organisms are still poorly understood. Hence, the focus of the present review is to describe the role of coloration in teleosts as well as potential ecotoxicological effects elicited by exposure to tyrosinase inhibitors. Furthermore, this review introduces our recently registered adverse outcome pathway (AOP) related to tyrosinase inhibition and population decline in teleosts.