Particulate matter (PM) generally comprises such chemical components as inorganic ions, organic carbon (OC), elemental carbon (EC), and metals. In terms of environmental studies, these major chemical components of particulate matter (MCP) are important in understanding PM distribution, behaviors and source apportionment. In this study, the MCP fractions of total suspended particles (TSP) were measured at an urban residential area in Seoul, Korea from February to December in 2009. The behavior of each individual MCP was studied in order to explain their relationship to environmental conditions and sources. The MCP measured during this study period was able to account between 54% (spring) to 67% (fall) of total TSP composition. During the study period, it was found that the TSP sampled comprised mostly: anions, OC, cations, EC, and metals in decreasing order of abundance. Although such relative ordering seems to remain fairly constant over time, the relative balance of this relationship may be altered by variations in environmental conditions.
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http://dx.doi.org/10.1016/j.chemosphere.2013.09.050 | DOI Listing |
J Am Chem Soc
January 2025
Key Laboratory for Advanced Materials, Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Institute of Fine Chemicals, School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, P. R. China.
Understanding and effectively controlling molecular conformational changes are essential for developing responsive and dynamic molecular systems. Here, we report that an oriented external electric field (OEEF) is an effective catalyst for the cis-trans isomerization of stiff-stilbene, a key component of overcrowded alkene-based rotary motors. This reversible isomerization occurs under ambient conditions, is free from side reactions, and has been verified using ultraperformance liquid chromatography and UV-vis absorption spectroscopy.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012, India.
Despite tremendous progress of dienamine catalysis along with its application in enantioselective synthesis over nearly two decades, certain limitations, especially with respect to the regioselectivity in the dienamine generation step, continue to persist. To overcome these shortcomings of classical dienamine catalysis, we now introduce the concept of alkoxy-directed dienamine catalysis and apply it to the enantioselective arene construction by desymmetrizing -enediones through [4 + 2]-cycloaddition. Catalyzed by a diphenylprolinol silyl ether, this reaction utilizes γ-alkoxy α,β-unsaturated aldehydes as the substrate and proceeds in a highly regioselective fashion through the intermediacy of δ-alkoxy dienamine.
View Article and Find Full Text PDFPest Manag Sci
January 2025
Dpto. Microbiología, Facultad de Ciencias, Universidad de Málaga, Málaga, Spain.
Background: Chitin is a crucial component of fungal cell walls and an effective elicitor of plant immunity; however, phytopathogenic fungi have developed virulence mechanisms to counteract the activation of this plant defensive response. In this study, the molecular mechanism of chitin-induced suppression through effectors involved in chitin deacetylases (CDAs) and their degradation (EWCAs) was investigated with the idea of developing novel dsRNA-biofungicides to control the cucurbit powdery mildew caused by Podosphaera xanthii.
Results: The molecular mechanisms associated with the silencing effect of the PxCDA and PxEWCAs genes were first studied through dsRNA cotyledon infiltration assays, which revealed a ≈80% reduction in fungal biomass and a 50% decrease in gene expression.
Pest Manag Sci
January 2025
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
Background: Bactrocera cucurbitae (Coquillett) is a distructive quarantine insect pest that causes significant economic losses on cucurbit crops. To explore a green control approach, we investigated the behavioral responses of B. cucurbitae larvae and adults to bacterial suspensions, sediments, and supernatants derived from eight gut microbial strains across four distinct genera.
View Article and Find Full Text PDFAdv Mater
January 2025
Materdicine Lab, School of Life Sciences, Shanghai University, Shanghai, 200444, China.
Cancer immunotherapy, which leverages immune system components to treat malignancies, has emerged as a cornerstone of contemporary therapeutic strategies. Yet, critical concerns about the efficacy and safety of cancer immunotherapies remain formidable. Nanotechnology, especially polymeric nanoparticles (PNPs), offers unparalleled flexibility in manipulation-from the chemical composition and physical properties to the precision control of nanoassemblies.
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