How-Ran Chao

Effects of methanol-containing additive on emission characteristics from a heavy-duty diesel engine

This study was aimed to investigate the effect of methanol-containing additive (MCA) on the regulated emissions of hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx), particulate matter (PM), as well as the unregulated carbon dioxide (CO2) and polycyclic aromatic hydrocarbons (PAHs) from a diesel engine. The engine was tested on a series of diesel fuels blended with five additive levels (0, 5, 8, 10 and 15% of MCA by volume). Emissions tests were performed under both cold- and hot-start transient heavy-duty federal test procedure (HD-FTP) cycles and two selected steady-state modes. Results show that MCA addition slightly decreases PM emissions but generally increases both THC and CO emissions. Decrease in NOx emissions was found common in all MCA blends. As for unregulated emissions, CO2 emissions did not change significantly for all MCA blends, while vapor-phase and particle-associated PAHs emissions in high load and transient cycle tests were relatively low compared to the base diesel when either 5 or 8% MCA was used. This may be attributed to the lower PAHs levels in MCA blends. Finally, the particle-associated PAHs emissions also showed trends quite similar to that of the PM emissions in this study.

Negative associations between PBDE levels and thyroid hormones in cord blood

Polybrominated diphenyl ethers (PBDEs) causing thyroidal effects have been demonstrated in in vivo and in vitro studies. PBDEs with structural similarities to thyroid hormones have increased recently, but the health effects for thyroid hormones have not been well studied. The study aimed to determine PBDE levels in cord blood and further to explore associations between prenatal PBDE exposures and thyroid hormones in cord blood. Fifty-four cord blood samples were collected after delivery. Cord-blood levels of BDE-15, 28, 47, 99, 100, 153, 154, and 183 were analyzed using a high resolution gas chromatograph with a high resolution mass spectrometer. Thyroid hormones were determined by an automated chemiluminescence analyzer. The mean, median, and standard deviation of ΣPBDEs were 4.72, 3.49, and 6.36 ng/g lipid, respectively. To adjust for confounding by maternal age, pre-pregnant BMI and gestational age, stepwise multiple linear regression was used after log(2) transformation of the exposure variables. A doubling of BDE-154 was associated with 0.043 ng/mL lower triiodothyronine (T3) values (adjusted r=-0.245, p=0.043). Likewise a doubling of BDE-153 was associated with 0.143 ng/mL lower free T3 (FT3) values and a doubling of BDE-183 with 0.084 ng/mL lower FT3 values (adjusted r=-0.487, p=0.023). In contrast, the T4 (thyroxine)/T3 ratio increased by 4.93 (adjusted r=0.277, p=0.017) when doubling BDE-100 exposure. No significant associations with BDE-47 or any other of the PBDEs was found. Our findings of an inverse relationship between BDE-153, BDE-154 or BDE-184 and thyroid hormones confirm the results of animal experiments but are in contrast to most epidemiological studies.

Zinc oxide particles induce inflammatory responses in vascular endothelial cells via NF-κB signaling.

This study investigated inflammatory effects of zinc oxide (ZnO) particles on vascular endothelial cells. The effects of 50 and 100-nm ZnO particles on human umbilical vein endothelial cells (HUVECs) were characterized by assaying cytotoxicity, cell proliferation, and glutathione levels. A marked drop in survival rate was observed when ZnO concentration was increased to 45 μg/ml. ZnO concentrations of ≤3 μg/ml resulted in increased cell proliferation, while those of ≤45 μg/ml caused dose-dependent increases in oxidized glutathione levels. Treatments with ZnO concentrations ≤45 μg/ml were performed to determine the expression of intercellular adhesion molecule-1 (ICAM-1) protein, an indicator of vascular endothelium inflammation, revealing that ZnO particles induced a dose-dependent increase in ICAM-1 expression and marked increases in NF-κB reporter activity. Overexpression of IκBα completely inhibited ZnO-induced ICAM-1 expression, suggesting NF-κB plays a pivotal role in regulation of ZnO-induced inflammation in HUVECs. Additionally, TNF-α, a typical inflammatory cytokine, induced ICAM-1 expression in an NF-κB-dependent manner, and ZnO synergistically enhanced TNF-α-induced ICAM-1 expression. Both 50 and 100-nm ZnO particles agglomerated to similar size distributions. This study reveals an important role for ZnO in modulating inflammatory responses of vascular endothelial cells via NF-κB signaling, which could have important implications for treatments of vascular disease.

Concentrations of polybrominated diphenyl ethers in breast milk correlated to maternal age, education level, and occupational exposure

The aim of the present study is to determine whether levels of polybrominated diphenyl ethers in breast milk in the general population are associated with demographic parameters, socioeconomic status, lifestyle factors, and occupational exposure. Forty-six participants are randomly selected from healthy women recruited between April 2007 and April 2008 from local hospitals in southern Taiwan. Thirty PBDE isomers in breast milk are analyzed using a gas chromatograph with a high resolution mass spectrometer. The mean+/-standard deviation of Sigma PBDEs in breast milk is 3.59+/-1.07 ng/g lipid. Our current value of Sigma PBDEs in breast milk is 0.7-fold lower compared to the past value in our previous study between 2000 and 2001. Higher levels of Sigma PBDEs might be significantly associated with older maternal age and maternal age of the present study is between 22 and 42 years old. Levels of Sigma PBDEs and certain PBDEs in breast milk are not correlated with maternal pre-pregnant BMI (Body mass index), parity, and lipid contents of breast milk. The Sigma PBDEs level in breast milk is lower in more educated women after controlling for age and pre-pregnancy BMI in our subjects. The main factors associated with Sigma PBDEs in breast milk are age and education level among the binary variables of demographic, socioeconomic, and lifestyle characteristics in this report. The exploratory relationships are found between PBDEs in breast milk and age, education level, or occupational exposure due to small sampling size.

Monitoring and modeling of PCB dry deposition in urban area

Abstract Dry deposition and air sampling were undertaken simultaneously in the ambient air of an urban site by using several dry deposition plates, two MOUDIs (micro-orifice uniform deposited impactors), one NRI (Noll rotary impactor) and several PS-1 (General Metal Work, PS-1) samplers from January to May 1994 in Tainan City, Taiwan. The dry deposition plate, which had a smooth surface, was always pointed into the wind. The PCB (polychlorinated biphenyl) congeners were analyzed primarily by using a gas chromatograph with a 63Ni electron capture detector (ECD). The measured dry deposition flux of total PCBs varied between 3.48 and 6.79 μg m−2 per day and averaged ≈ 4.73 μg m−2 per day. This was up to three orders of magnitude higher than the fluxes measured at the Great Lake and remote areas and close to those measured at urban areas by previous studies. The particle-bound PCB homologue composition collected by the dry deposition plate varied between 0.76 μg g−1 (di-CBs) and 11.5 μg g−1 (hexa-CBs). This profile of PCB homologues is similar to the pattern of Aroclor 1260 which is dominant in hexa-CBs and hepta-CBs. Because of their higher vapor pressure, in general, the less-chlorinated PCB homologues have a greater PCB mass fraction in the gas phase. The mean dry deposition velocities of PCB homologues ranged between 0.09 and 0.58 cm s−1. In general, the more highly chlorinated PCB homologues have a higher dry deposition velocity. Particle size distributions ( d C d(log D p ) vs. Dp) of total PCBs were found to be bimodal. The highest peak was localized in the particle size range between 5.6 and 10.0 μm and the second peak was localized in the particle size range between 0.31 and 0.52 μm. The particle MMD0 of total PCBs was 1.68 μm and more than 85% of the PCB mass was found in the particles smaller than 10 μm. By using the particle size distribution data, the dry deposition model used in this study can provide a good prediction for the dry deposition flux of total particle mass, total PCBs and PCB homologues. For both total particle mass and total PCBs, more than 87.5% of the dry deposition flux is contributed by particles of size > 10 μm. This is because particles larger than 10 μm have a higher dry deposition velocity (> 2.60 cm s−1) and, therefore, control the majority of the dry deposition flux.

Impact of non-occupational exposure to polybrominated diphenyl ethers on menstruation characteristics of reproductive-age females

Polybrominated diphenyl ethers (PBDEs) have documented effects on thyroid functions and rodent behavior in vivo. Epidemiological studies, however, have revealed only limited information about associations between PBDE exposure and menstruation characteristics. Our goal was to examine whether high breast milk PBDE levels in reproductive-age females lead to interference with menstruation characteristics. We analyzed 15 PBDE congeners in 46 breast milk samples. Fifteen PBDE congeners (BDE-15, 28, 47, 49, 99, 100, 153, 154, 183, 196, 197, 203, 207, 208, and 209) were analyzed using a gas chromatograph equipped with a high resolution mass spectrometer. The mean sum of PBDEs (SigmaPBDEs) in breast milk was 3.42 ng/g lipid. Womens age at menarche was not correlated with breast milk PBDE levels. Increased BDE-208 and 209 levels were significantly associated with the prolonged length of average and the longest menstrual cycle independent of age, pre-pregnant BMI, and parity. Higher concentrations of SigmaPBDEs and the higher brominated PBDEs from BDE-183 to 209, except 197, were significantly linked to women whose menstruation periods were still coming irregularly at the sampling time. Age-adjusted odds ratios (ORs) of BDE-153, 183, 207, 208, and SigmaPBDEs were significantly higher in women with length of average menstrual cycle >32 days, compared to the control. Women whose menstruation periods still came irregularly when they were 18 years old had higher age-adjusted ORs of BDE-207, 208, 209, and SigmaPBDEs than those whose periods came regularly at the same age. Although SigmaPBDEs and certain higher brominated PBDEs appear to have potential to prolong length of average menstrual cycle and delay the age when menstruation periods begin coming regularly, these findings are not conclusive because our sample size is small and more scientific evidence is needed.

Effects of arecoline on adipogenesis, lipolysis, and glucose uptake of adipocytes—A possible role of betel-quid chewing in metabolic syndrome

To investigate the possible involvement of betel-quid chewing in adipocyte dysfunction, we determined the effects of arecoline, a major alkaloid in areca nuts, on adipogenic differentiation (adipogenesis), lipolysis, and glucose uptake by fat cells. Using mouse 3T3-L1 preadipocytes, we showed that arecoline inhibited adipogenesis as determined by oil droplet formation and adipogenic marker gene expression. The effects of arecoline on lipolysis of differentiated 3T3-L1 adipocytes were determined by the glycerol release assay, indicating that arecoline induced lipolysis in an adenylyl cyclase-dependent manner. The diabetogenic effects of arecoline on differentiated 3T3-L1 adipocytes were evaluated by the glucose uptake assay, revealing that > or = 300 microM arecoline significantly attenuated insulin-induced glucose uptake; however, no marked effect on basal glucose uptake was detected. Moreover, using 94 subjects that were randomly selected from a health check-up, we determined the association of betel-quid chewing with hyperlipidemia and its related risk factors. Hyperlipidemia frequency and serum triglyceride levels of betel-quid chewers were significantly higher than those of non-betel-quid chewers. In this study, we demonstrated that arecoline inhibits adipogenic differentiation, induces adenylyl cyclase-dependent lipolysis, and interferes with insulin-induced glucose uptake. Arecoline-induced fat cell dysfunction may lead to hyperlipidemia and hyperglycemia/insulin-resistance. These findings provide the first in vitro evidence of betel-quid chewing modulation of adipose cell metabolism that could contribute to the explanation of the association of this habit with metabolic syndrome disorders.

PAH Emission from a Gasoline-Powered Engine

Abstract A gasoline powered engine operated on a dynamometer was used to investigate the PAH (Polycyclic Aromatic Hydrocarbons) emission. A 95‐leadfree gasoline (95‐LFG) and a premium leaded gasoline (PLG) were used as power‐fuels. The engine was simulated for the idling condition and for the cruising speeds at 40, 80 and 110 km/hr. The concentrations of 21 individual PAHs in the engine exhaust, gasolines, and the ambient air were determined. Engine exhaust samples were collected by a PAH sampling system, while the ambient air sample was collected by using a standard PS‐1 sampler. Twenty one individual PAHs were analyzed primarily by a gas chromatography/mass spectrometer (GC/MS). Naphthalene (Nap) has the highest concentration in the liquid phase of both 95‐LFG and PLG, in which it accounts for respectively 98.3% and 76.6% of the total PAH. In term of the mean fraction of the total PAHs entering the 95‐LFG and PLG engines, the ambient air contributed less than 0.108% and 0.012%, respectively. Gasoline is...

Breast-milk levels of polybrominated diphenyl ether flame retardants in relation to women's age and pre-pregnant body mass index

The aim of the present study was to determine associations between the occurrence of PBDEs in breast milk of women and their demographic parameters. Participants were randomly recruited from the general population in southern Taiwan. Thirty two breast milk samples were collected and subsequently 30 congeners of PBDEs were analyzed using a high resolution gas chromatograph with a high resolution mass spectrometer. The mean and median of SigmaPBDEs were 3.54 and 3.31 ng/g lipid, respectively. SigmaPBDE levels in breast milk were not significantly correlated with age and pre-pregnant BMI of Taiwanese mothers. We did find, however, that the higher hexaBDE level was significantly related to older age (>29 years). Higher levels of SigmaPBDEs and higher brominated PBDEs, such as nonaBDEs and decaBDE, had slightly but not significantly negative correlations with lower pre-pregnant BMI (< or =21 kg/m(2)). There were no significant differences in PBDE levels among parity and ethnic groups. SigmaPBDE levels in Taiwanese breast milk were lower than those reported from the United States or Canada. SigmaPBDE levels of the present study (2007-2008) are significantly lower than those found in our previous report (2000-2001). Although our results were limited by the sampling size, preliminary results suggest the exploratory relations to show positive associations of PBDE homologues (e.g. triBDEs and hexaBDEs) with maternal age. PBDEs pattern of breast milk may have changed after pentaBDEs were stopped to use in Taiwan.

Associations of polybrominated diphenyl ethers (PBDEs) in breast milk and dietary habits and demographic factors in Taiwan.

The aim of this study was to examine levels of PBDEs in breast milk associated with seafood consumptions of Taiwanese mothers. Our participants were selected from healthy women recruited between December 2000 and November 2001 from a medical center in central Taiwan. The congeners of PBDEs in 20 milk samples were analyzed by a gas chromatograph with a high resolution mass detector. The mean level of BDE47 in breast milk from mothers with pre-pregnant BMI <22.0kg/m2 had a significantly higher magnitude compared to those with pre-pregnant BMI > or = 22.0kg/m2 (1.59 vs. 0.995ng/g lipid, p=0.041). We did not find significant correlations between PBDEs exposure levels and womens age, parity, blood pressure, annual household income, and education level. Women who ate more fish and meat did not show significantly higher PBDE levels than those who ate less, but a significant difference in PBDE levels was demonstrated between the higher (2.15ng/g lipid) and lower (3.98ng/g lipid) shellfish consuming subjects (p=0.002) after an adjustment for the confounders. The ratios of PCB153/BDE47, PCB153/BDE153, and PCB153/PBDEs were significantly correlated with frequent consumption of fish and shellfish. The PCB153/BDE153 ratio was not associated with the other dietary habits (i.e. meat). The ratios of PCB153/PBDEs may therefore be a new indicator for exposure as a result of seafood consumption.