The aim of this study was to chemically characterize the fine particulate matter (PM2.5) at a subtropical forest in East Asia under the influences of anthropogenic and biogenic sources and a complex ...topographic setting. Four seasonal campaigns were conducted at the Xitou Experimental Forest in central Taiwan from the winter of 2013 to the autumn of 2014. The results indicated that the ambient levels and chemical features of PM2.5 exhibited pronounced seasonal variations. Non-sea-salt sulfate (nss-SO42-) constituted the major component of PM2.5, followed by ammonium (NH4+) and nitrate (NO3−) during winter, summer and autumn. However, it was revealed that the mass fraction of NO3− increased to be comparable with that of nss-SO42- in springtime. The mass contribution of secondary organic carbon (SOC) to PM2.5 peaked in summer (13.2%), inferring the importance of enhanced photo-oxidation reactions in SOC formation. Diurnal variations of O3 and SO2 coincided with each other, suggesting the transport of aged pollutants from distant sources, whereas CO and NOx were shown to be under the influences of both local and regional sources. Notably high sulfur oxidation ratio (SOR) and nitrogen oxidation ratio (NOR) were observed, which were 0.93 ± 0.05 and 0.39 ± 0.20, respectively. Precursor gases (i.e. SO2 and NOx) could be converted to sulfate and nitrate during the transport by the uphill winds. Furthermore, due to the high relative humidity at Xitou, enhanced aqueous-phase and/or heterogeneous reactions could further contribute to the formation of sulfate and nitrate at the site. This study demonstrated the significant transport of urban pollutants to a subtropical forest by the mountain-valley circulations as well as the long-range transport from regional sources, whereas the implications of which for regional climate change necessitated further investigation.
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•Distinct seasonal variations are observed in PM2.5 composition at forest site.•Notably high nitrate concentrations (6.19 μg/m3) are found in spring.•Significant secondary organic carbon (up to13.2% in summer) in PM2.5•The sulfur and nitrogen oxidation ratios are 0.93 and 0.39
Four measurement campaigns were conducted at Xitou Experimental Forest in central Taiwan to characterize the fine particulate matter (PM2.5) at a high-elevation subtropical forest in East Asia where pollutants were effectively transported by mountain-valley circulations, and long-range transport from regional sources.
Abstract
Transport and transformation of urban air pollutants are among the major factors driving the changes in the atmospheric composition in the downwind rural/remote areas of a megacity. Here, we ...assess the impacts of urban air pollution in a subtropical forest through characterization of the organic markers in submicron aerosol particles. The aerosol samples were collected and analyzed using TD-PTR-ToF-MS, where 163 ions were detected. The concentration of these extracted ions accounts for 83% of the mass of submicron organic aerosols, which are accordingly characterized by a median formula of C
7
H
10
O
2
. Molecular speciation indicates that urban and biomass burning pollution contributed substantially to the budget of organic aerosols, which were enhanced particularly by the liquid water content and acidity of the aerosols. Our results evidence that the footprint of urban air pollution was extended to its downwind forested areas and caused changes in the concentration and composition of submicron aerosols.
Organonitrates (ONs) are an important component of atmospheric aerosols that signify the perturbation of nitrogen oxides (NOx) pollution in the remote atmosphere. This study investigated the mass ...concentration and molecular composition of ONs in submicron particulate matters (PM1) at a subtropical forest site (Xitou), which located downwind the Taichung metropolis in the Central Taiwan. Here we showed that transport of urban air pollution with local circulations caused elevation in the ambient concentration of ONs in the forested area. In addition, the levels of ONs were positively correlated with ozone mixing ratio and were negatively correlated with the relative humidity, suggesting that the ONs were regulated by photochemistry and hydrolysis. The results also showed that the mass concentration of the ONs was significantly correlated with the number density of nanoparticles (d < 100 nm), implying the role of ONs in the formation and/or growth processes of atmospheric aerosols. Mass spectra analysis revealed five major ONs, which were characterized by the molecular skeletons of either isoprene or monoterpenes. The molecular profiles suggested that the reactions between nitrate radicals and biogenic volatile organic compounds (BVOCs) significantly contributed to the formation of ONs, which thereby represented a major sink of the functional BVOCs in the forested area.
•Both the mass concentration and the molecular identity of particulate organonitrates were determined using a TD-PTR-TOF-MS.•Photochemistry and hydrolysis dictated the mass concentration of organonitrates•Nitrate (NO3) initiated oxidation of BVOCs participated in the formation of organonitrates in daytime•NOx pollution enhanced formation of organonitrates and the sink of functional BVOCs in a forested area
Cellulolytic Enzyme Production and Enzymatic Hydrolysis for Second-Generation Bioethanol Production, by Mingyu Wang, Zhonghai Li, Xu Fang, Lushan Wang und Yinbo QuBioethanol from Lignocellulosic ...Biomass, by Xin-Qing Zhao, Li-Han Zi, Feng-Wu Bai, Hai-Long Lin, Xiao-Ming Hao, Guo-Jun Yue und Nancy W. Y. Ho Biodiesel From Conventional Feedstocks, by Wei Du und De-Hua Liu Establishing Oleaginous Microalgae Research Models for Consolidated Bioprocessing of Solar Energy, by Dongmei Wang, Yandu Lu, He Huang und Jian XuBiobutanol, by Hongjun Dong, Wenwen Tao, Zongjie Dai, Liejian Yang, Fuyu Gong, Yanping Zhang und Yin LiBranched-Chain Higher Alcohols, by Bao-Wei Wang, Ai-Qin Shi, Ran Tu, Xue-Li Zhang, Qin-Hong Wang und Feng-Wu BaiAdvances in Biogas Technology, by Ai-Jie Wang, Wen-Wei Li und Han-Qing Yu Biohydrogen Production from Anaerobic Fermentation, by Ai-Jie Wang, Guang-Li Cao und Wen-Zong Liu Microbial Fuel Cells in Power Generation and Extended Applications, by Wen-Wei Li and Guo-Ping Sheng Fuels and Chemicals from Hemicellulose Sugars, by Xiao-Jun Ji, He Huang, Zhi-Kui Nie, Liang Qu, Qing Xu and George T. Tsao
The aim of this study is to develop a novel robotic surgical platform, the IRISS (Intraocular Robotic Interventional and Surgical System), capable of performing both anterior and posterior segment ...intraocular surgery, and assess its performance in terms of range of motion, speed of motion, accuracy, and overall capacities.
To test the feasibility of performing 'bimanual' intraocular surgical tasks using the IRISS, we defined four steps out of typical anterior (phacoemulsification) and posterior (pars plana vitrectomy (PPV)) segment surgery. Selected phacoemulsification steps included construction of a continuous curvilinear capsulorhexis and cortex removal in infusion-aspiration (I/A) mode. Vitrectomy steps consisted of performing a core PPV, followed by aspiration of the posterior hyaloid with the vitreous cutter to induce a posterior vitreous detachment (PVD) assisted with triamcinolone, and simulation of the microcannulation of a temporal retinal vein. For each evaluation, the duration and the successful completion of the task with or without complications or involuntary events was assessed.
Intraocular procedures were successfully performed on 16 porcine eyes. Four eyes underwent creation of a round, curvilinear anterior capsulorhexis without radialization. Four eyes had I/A of lens cortical material completed without posterior capsular tear. Four eyes completed 23-gauge PPV followed by successful PVD induction without any complications. Finally, simulation of microcannulation of a temporal retinal vein was successfully achieved in four eyes without any retinal tears/perforations noted.
Robotic-assisted intraocular surgery with the IRISS may be technically feasible in humans. Further studies are pending to improve this particular surgical platform.
Recently, strategies for acute myeloid leukemia (AML) therapy have been developed that target anti-apoptotic BCL2 family members using BH3-mimetic drugs such as ABT-737. Though effective against BCL2 ...and BCL-X(L), ABT-737 poorly inhibits MCL-1. Here we report that, unexpectedly, ABT-737 induces activation of the extracellular receptor activated kinase and induction of MCL-1 in AML cells. MEK inhibitors such as PD0325901 and CI-1040 have been used successfully to suppress MCL-1. We report that PD0325901 blocked ABT-737-induced MCL-1 expression, and when combined with ABT-737 resulted in potent synergistic killing of AML-derived cell lines, primary AML blast and CD34+38-123+ progenitor/stem cells. Finally, we tested the combination of ABT-737 and CI-1040 in a murine xenograft model using MOLM-13 human leukemia cells.Whereas control mice and CI-1040-treated mice exhibited progressive leukemia growth, ABT-737, and to a significantly greater extent, ABT-737+CI-1040 exerted major anti-leukemia activity. Collectively, results demonstrated unexpected anti-apoptotic interaction between the BCL2 family-targeted BH3-mimetic ABT-737 and mitogen-activated protein kinase signaling in AML cells: the BH3 mimetic is not only restrained in its activity by MCL-1, but also induces its expression. However, concomitant inhibition by BH3 mimetics and MEK inhibitors could abrogate this effect and may be developed into a novel and effective therapeutic strategy for patients with AML.
In this study, we investigated the biodegradation of the phthalate acid esters (PAEs) di-
n-butyl phthalate (DBP) and di-(2-ethyl hexyl) phthalate (DEHP) in compost and compost-amended soil. DBP (50
...mg
kg
−1) and DEHP (50
mg
kg
−1) were added to the two types of compost (straw and animal manure) and subsequently added to the soil; they were tested as a single compound and in combination. Optimal PAE degradation in soil was at pH 7 and 30
°C. The degradation of PAE was enhanced when DBP and DEHP were simultaneously present in the soil. The addition of either of the two types of compost individually also improved the rate of PAE degradation. Compost samples were separated into fractions with various particle size ranges, which spanned from 0.1–0.45 to 500–2000
μm. We observed that the compost fractions with smaller particle sizes demonstrated higher PAE degradation rates. When the different compost fractions were added to soil, however, compost particle size had no significant effect on the rate of PAE degradation.
Environmental nanoparticles exist in the hydrosphere, pedosphere, biosphere, and atmosphere. Their biogeochemical and ecological impacts are some of the fastest growing areas of research today. ...However, efficient separation of environmental nanoparticles remains difficult. The objective of this study was to develop an automated ultrafiltration device (AUD) for efficient collection of environmental nanoparticles. The AUD utilizes an automated hydraulic ram to facilitate collection of nanoparticles using the ultrafiltration membrane with pore size in the range of 1 to 100 nm. Zeolite A was used as a model nanoparticle sample to demonstrate the efficiency of the AUD. The size distribution and mean particle sizes determined by zeta‐sizer analysis on the collected nanoparticles and their transmission electron micrographs indicated the adequacy of the AUD developed in this study in collecting nanoparticles (1–100 nm). Because of its ability to reduce the time needed for sample collection, coupled with the quantity of nanoparticles collected, the AUD was far more efficient than the conventional syringe method for collecting nanoparticles. The AUD has the characteristics of automation, easy operation, and high efficiency in the separation of nanoparticles and would, thus, facilitate future research and developments in environmental nanoscience and nanotechnology and their impacts on the ecosystem.
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