Benzoselenadiazole-Functionalized H-bonded Arylamide Foldamers: Solvent-Responsive Properties and Helix Self-Assembly Directed by Chalcogen Bonding in Solid State.

In this study, a series of H-bonded arylamide foldamers bearing benzoselenadiazole ends with solvent-responsive properties have been synthesized. In dichloromethane or dimethyl sulfoxide solvents, the molecules exhibit meniscus or linear structures, respectively, which can be attributed to the unique intramolecular hydrogen bonding behavior evidenced by 1D 1H NMR and 2D NOESY spectra. UV-vis spectroscopy experiments show that the absorption wavelength of H-bonded arylamide foldamers are significantly red-shifted due to the presence of benzoselenadiazole group. In addition, the crystal structures reveal that effective intermolecular dual Se···N interactions between benzoselenadiazole groups induce further assembly of the monomers. Remarkably, supramolecular linear and double helices structures are constructed under the synergistic induction of intramolecular hydrogen bonding and intermolecular chalcogen bonding. Additionally, 2D DOSY diffusion spectra and theoretical modelling based on density functional theory (DFT) are performed to explore the persistence of intermolecular Se···N interactions beyond the crystalline state.

Emission Characteristics of Particulate and Gaseous Pollutants from a Light-Duty Diesel Engine with SDPF.

Due to the inherent combustion characteristics of diesel engines, particulate matter (PM) and nitrogen oxides (NOx) are the main pollutants of diesel engines. NOx emissions under low load and low temperature are the focus of future regulation. Selective catalytic reduction coated on diesel particulate filter (SDPF) can reduce NOx and PM emissions of diesel engines at the same time, especially improving the emission characteristics of NOx under low load and low temperature. In this paper, a light-duty diesel engine with diesel oxidation catalyst (DOC) and SDPF was studied, and emission of particulate and gaseous pollutants of the engine before DOC, after DOC, and after SDPF was measured under 10 steady-state operating conditions. The effects of SDPF on particulate size distribution, the filtration efficiency of particulate, and the conversion efficiency of gaseous pollutants were analyzed. The results show that DOC + SDPF can trap PM with particle sizes between 10 and 23 nm by 1-2 orders of magnitude, and the conversion and filtration efficiency of DOC + SDPF for both gaseous pollutants and PM exceeds 90% under low-temperature and low-load conditions. The filtration efficiency of SDPF is 94.37% for PM and 90.36% for PN, and the conversion efficiency is 91.43% for NOx.

Two and three-dimensional halogen-bonded frameworks: self-assembly influenced by crystallization solvents.

In this paper, two types of solid phase 2D and 3D XBOFs were selectively constructed from identical building blocks of tetraphenylmethane tetrapyridine derivative and 1,4-diiodotetrafluorobenzene by changing the crystallization solvent. This 3D XBOF is a novel hybrid supramolecular organic framework with the synergistic control of hydrogen and halogen bonds.

Inhibition of Matrix Metalloproteinase-8 Protects Against Sepsis Serum Mediated Leukocyte Adhesion.

PURPOSE: Leukocyte adhesion to vascular and matrix Metalloproteinase-8 (MMP8) expression is increased in sepsis and associated with poor prognosis in sepsis patients. This study aimed to investigate the role of MMP8 in sepsis serum mediated leukocyte adhesion. METHODS: Bioinformatics analysis of GSE64457 and GSE65682 was performed to evaluate the role of MMP8 in the progression of sepsis. Expression of MMP8 in blood samples from patients with sepsis was detected by qRT-PCR and ELISA. Human umbilical vein endothelial cells (HUVECs) were treated with sepsis serum, control serum, and MMP8 inhibitor. Expression of vascular cell adhesion molecule-1 (VCAM-1) and intercellular cell adhesion molecule-1 (ICAM-1) were detected by qRT-PCR and ELISA, respectively. The protein expression of total p38, phosphorylated-p38, ERK1/2, and p-ERK1/2 was detected by Western blotting. Peripheral blood mononuclear cells (PBMCs) and polymorphonuclear neutrophils (PMNs) were incubated with the treated HUVECs to calculate leukocyte adhesion. RESULTS: Four hundred and twenty-nine differentially expressed genes (DEGs) and seven hub genes between sepsis patients and healthy controls were identified. GO function analysis of DEGs and hub genes indicated that the DEGs and hub genes were mainly enriched in neutrophil activation. MMP8 was selected as a key gene with an unfavorable prognosis in sepsis patients. The mRNA and protein expression of MMP8 in blood from sepsis patients were significantly higher than controls. Leukocyte adhesion and mRNA and protein expression of VCAM-1 and ICAM-1 were significantly increased in the sepsis serum group compared to that in the control group, as was the protein expression of p-p38 and p-ERK1/2. However, the MMP8 inhibitor suppressed the leukocyte adhesion promoted by sepsis serum by decreasing the expression of VCAM-1, ICAM-1, p-p38, and p-ERK1/2. CONCLUSION: Our study indicated that MMP8 acts as a key gene in the development of sepsis, and sepsis serum promotes leukocyte adhesion to HUVECs via MMP8, which suggest that MMP8 might be a potential therapeutic target for sepsis.

BCAR1 plays critical roles in the formation and immunoevasion of invasive circulating tumor cells in lung adenocarcinoma.

Background: We investigated the roles of breast cancer anti-estrogen resistance 1 (BCAR1/p130Cas) in the formation and immunoevasion of invasive circulating tumor cells (CTCs) in lung adenocarcinoma (LUAD). Methods: Biomarkers of CTCs including BCAR1 and CD274, were evaluated by the CanPatrol method. Proteomics analysis of LUAD cells and exosomes after BCAR1 overexpression (BCAR1-OE) was performed by mass spectrometry. Cell functions and relevant signaling pathways were investigated after BCAR1 knockdown (BCAR1-KO) or BCAR1-OE in LUAD cells. Lastly, in vitro and in vivo experiments were performed to confirm the roles of BCAR1 in the formation and immunoevasion of CTCs. Results: High expression of BCAR1 by CTCs correlated with CD274 expression and epithelial-to-mesenchymal transition (EMT). RAC1, together with BCAR1, was found to play an important role in the carcinogenesis of LUAD. RAC1 functioned with BCAR1 to induce EMT and to enhance cell proliferation, colony formation, cell invasion and migration, and anoikis resistance in LUAD cells. BCAR1 up-regulated CD274 expression probably by shuttling the short isoform of BRD4 (BRD4-S) into the nucleus. CTCs, as well as tumor formation, were prohibited in nude mice xenografted with BCAR1-KO cells. The co-expression of BCAR1/RAC1 and BCAR1/CD274 was confirmed in LUAD. BCAR1 expression in LUAD is an indicator of poor prognosis, and it associates with immunoevasion. Conclusion: BCAR1, as a new target for the treatment of LUAD, plays roles in the formation and immunoevasion of invasive CTCs. The mechanism includes triggering EMT via RAC1 signaling and up-regulating CD274 expression by shuttling BRD4-S into the nucleus.

Interactions between Used Cooking Oil Biodiesel Blends and Elastomer Materials in the Diesel Engine.

Used cooking oil (UCO) biodiesel may be one of the most potential alternative fuels in China to lower the dependency on crude oil for transportation. An experimental study has been conducted to assess the interactions between biodiesel produced from UCO in Shanghai and elastomer materials on high-speed marine diesel engines by immersing elastomer materials into conventional fossil diesel, 5, 10, and 20%, of a volumetric blending ratio of UCO biodiesel and pure UCO biodiesel. The test duration is 168 h at different temperatures of 25, 50, and 70 °C. Meanwhile, the effects of the mixing ratio of UCO biodiesel and the immersion temperature on the compatibility of elastomer materials with UCO biodiesel were analyzed. The results revealed that elastomer materials such as nitrile butadiene rubber (NBR), ethylene propylene diene monomer (EPDM), fluororubber (FKM), and silicone rubber (SR) exposed to biodiesel blends would reveal worse but acceptable changes than those exposed to petroleum diesel, including the slight increase of mass and volume and decline of tensile strength and hardness. FKM, NBR, and SR represented better compatibility with pure UCO biodiesel than diesel, and EPDM showed worse compatibility with UCO biodiesel as the blend ratio rises. In general, the recommended volumetric mixing ratio of UCO biodiesel should be no larger than 20%. The present study could be helpful for the investigation of UCO biodiesel blends as a potential fuel to satisfy the energy demand.

Study of spatial and temporal aging characteristic of catalyzed diesel particulate filter catalytic performance used for diesel vehicle.

Catalyzed diesel particulate filters (CDPFs) have been widespread used as a technically and economically feasible mean for meeting increasingly stringent emissions limits. An important issue affecting the performance of a CDPF is its aging with using time. In this paper, the effects of noble metal loadings, regions and using mileage on the aging performance of a CDPF were investigated by methods of X-ray diffraction (XRD), X-ray photoelectron spectroscopy and catalytic activity evaluation. Results showed that aging of the CDPF shifted the XRD characteristic diffraction peaks towards larger angles and increased the crystallinity, showing a slowing downward trend with the increase of the noble metal loadings. In addition, the increase of the noble metal loading would slow down the decline of Pt and Pt4+ concentration caused by aging. The characteristic temperatures of CO, C3H8 conversion and NO2 production increased after aging, and the more the noble metal loadings, the higher the range of the increase. But noticeably, excessive amounts of noble metals would not present the corresponding anti-aging properties. Specifically, the degree of aging in the inlet region was the deepest, the following is the outlet region, and the middle region was the smallest, which were also reflected in the increase range of crystallinity, characteristic temperatures of CO, C3H8 conversion and NO2 production, as well as the decrease range of Pt and Pt4+ concentrations. The increase of aging mileage reduced the size of the aggregates of the soot and ash in CDPFs, however, improved the degree of tightness between particles. Meanwhile Carbon (C) concentration in the soot and ash increased with the aging mileage.

Remote ischemic post-conditioning protects against myocardial ischemia/reperfusion injury by inhibiting the Rho-kinase signaling pathway.

The aim of the present study was to observe the effect of Rho-kinase on remote ischemic post-conditioning (RIPostC) and explore the underlying mechanisms. Male Sprague Dawley rats (n=32) were randomly distributed into four groups: Sham group, ischemia/reperfusion (I/R) group, RIPostC group and I/R with fasudil group (I/R+Fas). Infarction size was detected by triphenyltetrazolium chloride staining. The levels of creatine kinase (CK), lactate dehydrogenase (LDH), superoxide dismutase (SOD), malondialdehyde (MDA) and cardiac troponin I (cTnI) were measured using an ultraviolet spectrophotometer. The mRNA expression levels of Rho-associated coiled-coil containing protein kinase (ROCK)-1 and ROCK2, B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax) were detected via reverse transcription-PCR. The protein expression levels of phosphorylated-myosin phosphatase target subunit (p-MYPT1) and phosphorylated-myosin light chain (p-MLC) were assessed by western blotting. The results demonstrated that RIPostC could decrease the infarct size, the levels of CK, LDH, cTnI and MDA and increase the activity of SOD compared with the I/R group. In addition, the mRNA expression of ROCK1 and ROCK2 was downregulated, the protein expression of p-MYPT1 and p-MLC was decreased, and the ratio of Bcl-2/Bax was elevated in the RIPostC groups compared with the I/R group. Notably, the aforementioned index in I/R with Fas group was similar to the RIPostC group and no significant difference was observed between RIPostC and I/R+Fas. These results revealed that RIPostC could attenuate I/R injury and the underlying mechanisms might be associated with a reduction in myocardial apoptosis and the suppression of the Rho-kinase signaling pathway.

Icotinib inhibits proliferation and epithelial-mesenchymal transition of non-small cell lung cancer A549 cells.

Objective: To investigate the inhibitory effect of Icotinib on proliferation and epithelial-mesenchymal transition of A549 cells. Methods: A549 cells were treated with Icotinib of different concentrations. The morphology of the cells was observed by inverted phase contrast microscope. The effect of different concentrations of Icotinib on the proliferation inhibition rate of A549 cells was detected by MTT assay. Flow cytometry was used to detect effect of Icotinib on the apoptosis rate of A549 cells. ELISA assay was used to detect the expression of EMT-related proteins, E-cadherin, N-cadherin, Vimentin and fibronectin, in A549 cells cultured supernatant. Transwell assay was used to examine the effects of different concentrations of Icotinib on the migration and invasion abilities of A549 cells. Results: Morphological changes were observed after A549 cells exposed to different concentrations of Icotinib for 48 hours. The inhibition rate of proliferation for each treatment group increased from MTT assay results. Flow cytometry results showed that cell apoptosis rate was significantly increased. Expression of E-cadherin was up-regulated and expression of N-cadherin, Vimentin and fibronectin were down-regulated from ELISA results. A549 cell migration and invasion abilities were significantly suppressed by Icotinib at different concentrations. Conclusion: Icotinib inhibits A549 cell proliferation, migration and invasion in both concentration and time-dependent manners, in turn it promotes A549 cell apoptosis in the same way. Icotinib also inhibits epithelial-mesenchymal transition by regulating EMT-related proteins expression in A549 cells.

A phenomenological model for particle number and size distributions of a diesel engine with a diesel oxidation catalyst.

Particle number is a key index for evaluating particulate emissions, and diesel oxidation catalysts (DOCs) are one of the most important technologies for controlling the particulate emissions of a diesel engine. In this paper, a novel phenomenological one-dimensional model was established to predict particle number and size distributions at a DOC outlet with the aim of investigating the effects of DOC on particle number emissions. The phenomenological model consisted of two submodels: submodel-1, a global kinetic model for calculating particle size in particle number and size distributions after particles had passed through the DOC, and submodel-2, an original global parametric model for calculating the particle number at the DOC outlet. The effects of the sampling process, fuel properties, and the engine operating condition were considered in submodel-2. An 8.8 L, direct-injection, heavy-duty diesel engine was tested. The particle number and size distributions at the DOC inlet and outlet were determined using an engine exhaust particle sizer. The test data, coupled with literature results, were used to calibrate and validate the phenomenological model. This model was then applied to investigate the influence of various factors on particle number and size distributions at the DOC outlet. It was found that dilution temperature, fuel sulfur content, exhaust gas temperature, and gas hourly space velocity (GHSV) played a key role in the particle number after DOC oxidation. The particle number concentration at the DOC outlet increased as fuel sulfur content and exhaust gas temperature increased and decreased as GHSV and dilution temperature increased. In general, results proved that this phenomenological model was accurate enough to predict particle number and size distributions at a DOC outlet under most operating conditions. It may serve as a useful tool for research and development focusing on PM reduction of diesel engines and air pollution control.

[Pollutant Emissions from Diesel Buses Fueled with Waste Cooking Oil Based Biodiesel].

Two diesel buses respectively certified to meet China Ⅲ and China Ⅴ emission standards were used as prototype vehicles, fixed on a heavy-duty chassis dynamometer and driven according to a typical city bus driving cycle to analyze the pollutant emissions and volatile organic compounds (VOCs). The buses were fueled with diesel and waste cooking oil based biodiesel with 10 vol% blend ratio (B10). The emissions of total hydrocarbon(THC), CO, particulate matter (PM), and the number of solid particles with a diameter of 23 nm to 2.5 µm (referred to as "solid particulate number of PM2.5") from the bus certified to meet China Ⅴ (referred to as "China V bus") were 39.3%, 19.9%, 77.4%, and 28.4% lower than those from the other bus certified to meet China Ⅲ (referred to as "China Ⅲ bus"), while NOx emissions were 31.7% higher. Moreover, alkanes, alkenes, aromatic hydrocarbons, and oxygenated compounds in VOCs emitted from the China V bus were lower than those emitted from the China Ⅲ bus, suggesting lower atmospheric reactivity and smaller potential of secondary organic aerosol formation. Compared with the emission results of two diesel-fueled buses, the B10-fueled buses emitted smaller amounts of THC, CO, PM, and solid particulate number of PM2.5, lower oxygenated compounds but higher alkenes; slightly higher NOx emissions than China Ⅲ but slightly lower NOx emissions than China V. Consequently, the atmospheric reactivity of VOCs in exhaust gas from the bus fueled with B10 was higher than that from the diesel-powered bus.

[Particulate Component Emission Characteristic from a Diesel Bus with DOC and CDPF].

A diesel bus was tested with a China City Bus Cycle (CCBC) on a heavy chassis dynamometer, and the components of the particulate emissions with different after-treatment equipment were investigated. Results showed that OC was less than EC in the particulates of the bus emissions without the use of after-treatment equipment. The organic components were mainly fatty acids (60.9%) and n-alkanes (32.4%), with a few hopanes and PAHs. Fatty acid components were mainly C16:0, C18, C14, and C18:1. The n-alkanes were mainly C18-C24, with C21H44 and C22H46 accounting for the greatest portion. PAH mass was concentrated in medium and small molecular weight components, such as Pyr, FL, and PA. While PAH toxicity was dominated by medium and high molecular weight components, BaP was the most toxic, followed by B(b+k)F, BaA, and IcdP. The total toxicity of the PAHs decreased by 2.7% after DOC treatment and continued to decrease by 89.6%-93.8% after CDPF treatment. After-treatment equipment significantly reduced the OC+EC emissions by 18.9% (DOC) and 70.5%-72.5% (CDPF), but the reduction rate varied from one component to another. The different precious metal loadings of the CDPF did not obviously affect the reduction rate.

[Effects of Different Precious Metal Loads of CDPF on Characteristics of VOCs Emissions from a Diesel Bus].

Based on heavy chassis dynamometers, an experimental study was conducted in a diesel bus with proton transfer reaction mass spectrometry (PTR-MS). It investigated the effects of volatile organic compound (VOC) emission characteristics with three different diesel oxidation catalyst (DOC)+catalyzed diesel particulate filter (CDPF) after-treatments for a typical Chinese city bus driving cycle (CCBC). The results reveal that the major compounds from the diesel bus are OVOCs, aromatic hydrocarbons, alkenes, alkanes, nitrogenous organic compounds, and polycyclic aromatic hydrocarbons (PAH), and that the OVOCs account for more than 50%of the total VOCs. With the same precious metal composition and ratio of the proportion in the CDPF catalyst, the emissions of VOCs decrease with an increase in precious metal load. The emission reduction rates of the VOCs are 36.2%, 40.1%, and 41.4%, respectively, when the precious metal loads are 15 g·ft-3 (type A after-treatment device), 25 g·ft-3 (type B), and 35 g·ft-3 (type C). The average emission rates of alkanes for the three kinds of DOC+CDPF after-treatments are all over 59% for the entire CCBC cycle. The type C after-treatment device can reduce the alkane emissions by 70.2%, with a slight advantage for the OVOC reduction compared with type A and type B devices. For unsaturated hydrocarbons, including aromatic hydrocarbons, alkenes, and PAHs, the after-treatment devices have a catalytic effect, but there is no significant difference between them. The emissions of nitrogenous organic compounds are greatly decreased, by 50.5%, with the type A after-treatment, but the reduction rate decreases with an increase in precious metal load. In addition, OVOCs, aromatic hydrocarbons, and alkenes are the most important contributors to ozone formation. The adoption of DOC+CDPF reduces the emissions of VOCs and, therefore, the ozone formation potential. Taking into account the emission reduction rates and costs of the three different after-treatments and for weighting coefficients of 0.8 and 0.2, respectively, the type B after-treatment is the optimal solution.

[Effects of DOC+CDPF on Emission Characteristics of Heavy-duty Diesel Vehicle].

Based on the revolving drum test bench, an experimental study was conducted in heavy-duty diesel vehicle at China Stage Ⅲ with and without DOC+CDPF to investigate the effects of DOC+CDPF on the gaseous and particle emission characteristics under C-WTVC driving cycle. The results showed that from city circulation conditions to high way circulation conditions to high-speed circulation conditions, the CO, THC, CO2 and PM emission factors of the test vehicle without DOC+CDPF decreased while NOx and PN emission factors increased, the particle number concentration showed two peaks versus the size of the particles and accumulated particles predominated. After the test vehicle was equipped with DOC+CDPF, the emissions factors decreased and the faster the circulation speed, the greater the decreasing amplitudes of the emissions factors. Throughout the C-WTVC, the decreasing amplitudes of CO, THC, CO2, and NOx emission factors were 70.36%, 72.73%, 17.00% and 7.76%, the PM and PN emission factors decreased by 93.77% and 98.91% respectively. The particle number concentration still had two peaks versus the size of the particles and the nuclear mode particles predominated. Besides, the size of the accumulated particles peak diminished.

[Influence of Noble Metal and Promoter Capacity in CDPF on Particulate Matter Emissions of Diesel Bus].

This study investigates the influence of noble metal capacity and promoter capacity in diesel oxidation catalysts (DOC) and catalyzed diesel particulate filters (CDPF) on particulate matter (PM) emissions. Four types of exhaust aftertreatments were applied to a diesel bus engine that meets the national Ⅲ emissions regulations. On-board tests were conducted respectively. PM emissions from the engine were strongly influenced by noble metal capacity in DOC and CDPF, especially at high speeds (the total number of particles increased by 70.8% when the noble metal capacity decreased by 5 g·ft-3 at 60 km·h-1). The higher the noble metal capacity was, the lower the PM emissions became, especially for PM in nuclei mode. The lanthanide material contributed to reducing PM emissions significantly. The content of precious metals could be reduced by 25% with proper lanthanide material, while the treatment effect of exhaust particles was guaranteed. In summary, aftertreatments are not sensitive to accelerating conditions, but the purification efficiency is obviously different under decontamination conditions.

[Emission Characteristics of Particulate Matter from Diesel Buses Meeting Different China Emission Standards Fueled with Biodiesel].

Based on heavy chassis dynamometer, an experimental study was conducted in diesel buses compliant with China Ⅲ,Ⅳ,Ⅴ emissions standards respectively, fueled with three different blends of petroleum diesel/biodiesel (0%,5%and 10%, V/V biodiesel blends), which investigated the characteristics of particulate matter (PM) emission under CCBC driving cycle. Results of study showed that the total PM number and mass emission from China Ⅴ bus respectively decreased by 68.1%,56.2%,57.5% and 52.7%,64.8%, 88.5% compared to China Ⅲ bus. When compared to China Ⅳ bus, the PM mass emission decreased by 43.0%, 47.3% and 42.1%, while the number increased by 4.0%,7.6% and 14.7%. The nucleation mode PM emission of China Ⅲ bus was mainly from high-speed driving condition, while China Ⅳ and Ⅴ buses were from middle-low speed. The accumulation mode PM emissions of China Ⅲ, Ⅳ and V buses were all mainly from middle-low speed driving conditions. In relatively lower speed conditions, compared to China Ⅲ bus, the nucleation mode PM emissions of China Ⅳ and Ⅴ buses obviously decreased, so was accumulation mode PM. Compared to China Ⅳ bus, emission of China Ⅴ bus did not improve obviously and the nucleation mode PM emission even increased. In high-speed driving condition, the nucleation mode PM emission from China Ⅲ bus increased dramatically, while those from China Ⅴ and Ⅳ buses slightly increased. Meanwhile, the accumulation PM number and mass emission of China Ⅳ bus was obviously higher than those of China Ⅴ and Ⅲ buses. When fueled with B10, the relatively bigger sizes PM emission of China Ⅲ bus deteriorated rapidly, indicating that China Ⅲ bus was not suitable for fuel with high blending ratio of biodiesel.

[Effect of DOC/CCRT Aging on Gaseous Emission Characteristics of an In-used Diesel Engine Bus].

Based on heavy chassis dynamometer, an experimental study was conducted in diesel bus with China Stage Ⅲ, which investigated the effects of gaseous emission characteristics under CCBC driving cycle, such as carbon monoxide (CO), total hydrocarbons (THC), nitric oxide (NO), nitrogen dioxide (NO2), nitrogen oxides (NOx) and carbon dioxide (CO2) with the fresh/aged oxidized catalyst (DOC) and oxidation catalysts coupled catalyzed particulate trap (DOC+CDPF, referred CCRT). The results showed that using fresh and aged DOC/CCRT, the diesel bus could reduce CO, THC and NO emissions, meanwhile increase NO2 emissions, but NOx and CO2 emissions remained basically unchanged. In idle speed, acceleration, deceleration and constant speed of working conditions, the diesel bus using the fresh DOC had better oxidation efficiency of the CO and THC emissions than the bus using the aged DOC. The diesel bus using the fresh CCRT had higher oxidation efficiency of THC emissions, but lower oxidation efficiency of CO emissions than the bus using the aged CCRT. The diesel bus using the fresh DOC/CCRT had a higher rate of NO emissions reductions and NO2 emissions increments than the bus using the aged DOC/CCRT, but it did not basically affect the NOx emissions.

[Emission Characteristics of Gaseous Pollutants from City Bus Fueled with Biodiesel Based on DOC+CDPF Technology in Real Road Conditions].

The gaseous emissions of stage Ⅲ standard City bus with and without DOC+CDPF after-treatment fueled with biodiesel blends on real road in steady-state and transient conditions were studied using OBS-2200 gaseous portable emission measurement. The results showed that B20 led to a decrease of CO and THC emission rates compared with those of B0. In steady-state condition, CO and THC average mass emission rates of B20 decreased by 26.43% and 10.44% respectively and in transient condition the decrease rates were 22.78% and 4.95%. Meanwhile, B20 eventuated in higher CO2 and NOx emission rates. In steady-state condition, CO2 and NOx average mass emission rates of B20 increased by 8.41% and 8.26% respectively and in transient condition the increase rates were 7.15% and 9.13%. DOC+CDPF caused a more obvious reduction of CO and THC emission rates of B20 compared with B0. In steady-state condition, CO and THC average emission rates decreased by 60.58% and 79.92%, while in transient condition they decreased by 63.67% and 82.57%. The influence of DOC+CDPF on emission reduction of CO2 and NOx was not obvious.

[Particle emission characteristics of diesel bus fueled with bio-diesel].

With the use of the Engine Exhaust Particle Sizer (EEPS), a study on the characteristics of particle emissions was carried out on a China-IV diesel bus fueled with blends of 5% , 10% , 20% , 50% bio-diesel transformed from restaurant waste oil and China-IV diesel (marked separately by BD5, BD10, BD20, BD50), pure bio-diesel (BD100) and pure diesel (BD0). The results indicated that particulate number (PN) and mass (PM) emissions of bio-diesel blends increased with the increase in bus speed and acceleration; with increasing bio-diesel content, particulate emissions displayed a relevant declining trend. In different speed ranges, the size distribution of particulate number emissions (PNSD) was bimodal; in different acceleration ranges, PNSD showed a gradual transition from bimodal shape to unimodal when bus operation was switched from decelerating to accelerating status. Bio-diesel blends with higher mixture ratios showed significant reduction in PN emissions for accumulated modes, and the particulate number emission peaks moved towards smaller sizes; but little change was obtained in PN emissions for nuclei modes; reduction also occurred in particle geometric diameter (Dg).

[Emission characteristics of polycyclic aromatic hydrocarbons in exhaust particles from a diesel car].

The emission characteristics of polycyclic aromatic hydrocarbons (PAHs) in exhaust particles from a diesel car were studied. In the experiment, pure diesel fuel and B10 fuel with a biodiesel blend ratio of 10% were chosen. The gaseous emissions of HC, CO and NO(x) under New European Driving Cycle (NEDC) were measured, and exhaust particulate matter (PM) samples were analyzed by gas chromatography-mass spectrometry. The emission characteristics of PAHs in exhaust particles were highlighted. The results show that the emission concentrations of HC, CO, NO(x), and PM decreased when the diesel car used B10 fuel. Fluoranthene and pyrene were dominant in PAHs of PM emissions when the diesel car used pure diesel or B10 fuel. Compared to pure diesel, there was a slight increase in low-ring PAHs emissions when the diesel car used B10 fuel. On the contrary, PAHs emissions in middle and high-ring declined significantly. Besides, Benzo [ a] pyrene equivalent toxicity analysis results show that the BEQs of B10 fuel decreased by 21.6% compared to pure diesel. That means the toxicity of PAHs in exhaust particles declined when the diesel car used biodiesel fuel.