Exposure and health risk assessment of volatile organic compounds among drivers and passengers in long-distance buses.

Exposure to volatile organic compounds (VOCs) such as benzene, toluene, ethylbenzene, xylene, and formaldehyde from long-distance buses has been reported to adversely affect human health. This study investigates the concentrations of these five VOCs and evaluates their health risks to drivers and passengers on board. Ten trips from Taipei to Taichung were performed during the warm and cold seasons of 2021-2022. Two locations inside the bus were established to collect air samples by a 6-liter canister for drivers and passengers. Exposure concentrations of benzene, toluene, ethylbenzene, and xylene were analyzed via gas chromatography with a flame ionization detector and the formaldehyde concentration was monitored using a formaldehyde meter. Subsequently, a Monte Carlo simulation was conducted to evaluate the carcinogenic and non-carcinogenic risks of the five VOCs. Formaldehyde emerged as the highest detected compound (9.06 ± 3.77 µg/m3), followed by toluene (median: 6.11 µg/m3; range: 3.86-14.69 µg/m3). In particular, formaldehyde was identified to have the significantly higher concentration during non-rush hours (10.67 ± 3.21 µg/m3) than that during rush hours (7.45 ± 3.41 µg/m3) and during the warm season (10.71 ± 2.97 µg/m3) compared with that during the cold season (7.41 ± 4.26 µg/m3). Regarding non-carcinogenic risks to drivers and passengers, the chronic hazard indices for these five VOCs were under 1 to indicate an acceptable risk. In terms of carcinogenic risk, the median risks of benzene and formaldehyde for drivers were 2.88 × 10-6 (95% confidence interval [CI]: 2.11 × 10-6 - 5.13 × 10-6) and 1.91 × 10-6 (95% CI: 4.54 × 10-7 - 3.44 × 10-6), respectively. In contrast, the median carcinogenic risks of benzene and formaldehyde for passengers were less than 1 × 10-6 to present an acceptable risk. This study suggests that benzene and formaldehyde may present carcinogenic risks for drivers. Moreover, the non-carcinogenic risk for drivers and passengers is deemed acceptable. We recommended that the ventilation frequency be increased to mitigate exposure to VOCs in long-distance buses.

One-pot tandem reduction and site-selective halogenation of nitroarenes.

Halogenated aryl amines are a widely used chemical feedstock in the pharmaceutical and agrochemical industries. Achieving a single regioselective product from the para-selective halogenation of the aryl ring is significantly challenging because of the presence of several C-H bonds with similar reactivities. In this study, single para-halogenated aniline derivatives were prepared by the cascade para-selective halogenation (Cl, Br) and reduction of nitrobenzene derivatives using a mixture of SnCl2/SnCl4 salts. The mechanistic study confirmed that the noncovalent interactions between the chalcogen bond and Sn salt were pivotal for achieving regioselectivity. This synthetic method was applied for the development of potent and highly selective positron emission tomography molecular probes for serotonin transporters.

Application of artificial intelligence algorithms and low-cost sensors to estimate respirable dust in the workplace.

The Internet of Things (IoT) and low-cost sensor technology have become common tools for environmental exposure monitoring; however, their application in measuring respirable dust (RD) in the workplace remains limited. This study aimed to develop a predictive model for RD using artificial intelligence (AI) algorithms and low-cost sensors and subsequently assess its validity using a standard sampling approach. Various low-cost sensors were combined into an RD sensor module and mounted on a portable aerosol monitor (GRIMM 11-D) for two weeks. AI algorithms were used to capture data per minute over 14 days to establish predictive RD models. The best-fitting model was validated using an aluminum cyclone equipped with an air pump and polytetrafluoroethylene filters to sample the 8-hour RD for 5 days at an aircraft manufacturing company. This module was continuously monitored for two weeks to evaluate its stability. The RD concentration measured by GRIMM 11-D in a general outdoor environment over two weeks was 28.1 ± 16.1 µg/m3 (range: 2.4-85.3 µg/m3). Among the various established models, random forest regression was observed to have the best prediction capacity (R2 = 0.97 and root mean square error = 2.82 µg/m3) in comparison to the other 19 methods. Field-based validation revealed that the predicted RD concentration (35.9 ± 4.1 µg/m3, range: 32.7-42.9 µg/m3) closely approximated the results obtained by the traditional method (38.1 ± 8.9 µg/m3, range: 28.1-52.5 µg/m3), and a strong positive Spearman correlation was observed between the two (rs = 0.70). The average bias was -2.2 µg/m3 and the precision was 5.8 µg/m3, resulting in an accuracy of 6.2 µg/m3 (94.2 %). Data completeness was 99.7 % during the continuous two-week monitoring period. The developed sensor module of RD exhibited excellent predictive performance and good data stability that can be applied to exposure assessments in occupational epidemiological studies.

Climate change, air quality, and respiratory health: a focus on particle deposition in the lungs.

This review article delves into the multifaceted relationship between climate change, air quality, and respiratory health, placing a special focus on the process of particle deposition in the lungs. We discuss the capability of climate change to intensify air pollution and alter particulate matter physicochemical properties such as size, dispersion, and chemical composition. These alterations play a significant role in influencing the deposition of particles in the lungs, leading to consequential respiratory health effects. The review paper provides a broad exploration of climate change's direct and indirect role in modifying particulate air pollution features and its interaction with other air pollutants, which may change the ability of particle deposition in the lungs. In conclusion, climate change may play an important role in regulating particle deposition in the lungs by changing physicochemistry of particulate air pollution, therefore, increasing the risk of respiratory disease development.

Climate change influences particle deposition in the lungs by modifying the physicochemical properties of particulate air pollution, thereby escalating the risk of respiratory disease development.It is crucial for healthcare providers to educate patients about the relationship between climate change and respiratory health.People with conditions such as asthma, COPD, and allergies must understand how changes in weather, air pollution, and allergens can exacerbate their symptoms.Instruction on understanding air quality indices and pollen predictions, along with recommendations on adapting everyday activities and medication regimens in response, is essential.

The impact of air pollution on respiratory diseases in an era of climate change: A review of the current evidence.

The impacts of climate change and air pollution on respiratory diseases present significant global health challenges. This review aims to investigate the effects of the interactions between these challenges focusing on respiratory diseases. Climate change is predicted to increase the frequency and intensity of extreme weather events amplifying air pollution levels and exacerbating respiratory diseases. Air pollution levels are projected to rise due to ongoing economic growth and population expansion in many areas worldwide, resulting in a greater burden of respiratory diseases. This is especially true among vulnerable populations like children, older adults, and those with pre-existing respiratory disorders. These challenges induce inflammation, create oxidative stress, and impair the immune system function of the lungs. Consequently, public health measures are required to mitigate the effects of climate change and air pollution on respiratory health. The review proposes that reducing greenhouse gas emissions contribute to slowing down climate change and lessening the severity of extreme weather events. Enhancing air quality through regulatory and technological innovations also helps reduce the morbidity of respiratory diseases. Moreover, policies and interventions aimed at improving healthcare access and social support can assist in decreasing the vulnerability of populations to the adverse health effects of air pollution and climate change. In conclusion, there is an urgent need for continuous research, establishment of policies, and public health efforts to tackle the complex and multi-dimensional challenges of climate change, air pollution, and respiratory health. Practical and comprehensive interventions can protect respiratory health and enhance public health outcomes for all.

Ambient relative humidity-dependent obstructive sleep apnea severity in cold season: A case-control study.

BACKGROUND: The objective of this study was to examine associations of daily averages and daily variations in ambient relative humidity (RH), temperature, and PM2.5 on the obstructive sleep apnea (OSA) severity. METHODS: A case-control study was conducted to retrospectively recruit 8628 subjects in a sleep center between January 2015 and December 2021, including 1307 control (apnea-hypopnea index (AHI) < 5 events/h), 3661 mild-to-moderate OSA (AHI of 5-30 events/h), and 3597 severe OSA subjects (AHI > 30 events/h). A logistic regression was used to examine the odds ratio (OR) of outcome variables (daily mean or difference in RH, temperature, and PM2.5 for 1, 7, and 30 days) with OSA severity (by the groups). Two-factor logistic regression models were conducted to examine the OR of RH with the daily mean or difference in temperature or PM2.5 with OSA severity. An exposure-response relationship analysis was conducted to examine the outcome variables with OSA severity in all, cold and warm seasons. RESULTS: We observed associations of mean PM2.5 and RH with respective increases of 0.04-0.08 and 0.01-0.03 events/h for the AHI in OSA patients. An increase in the daily difference of 1 % RH increased the AHI by 0.02-0.03 events/h in OSA patients. A daily PM2.5 decrease of 1 µg/m3 reduced the AHI by 0.03 events/h, whereas a daily decrease in the RH of 1 % reduced the AHI by 0.03-0.04 events/h. The two-factor model confirmed the most robust associations of ambient RH with AHI in OSA patients. The exposure-response relationship in temperature and RH showed obviously seasonal patterns with OSA severity. CONCLUSION: Short-term ambient variations in RH and PM2.5 were associated with changes in the AHI in OSA patients, especially RH in cold season. Reducing exposure to high ambient RH and PM2.5 levels may have protective effects on the AHI in OSA patients.

Ranking the environmental factors of indoor air quality of metropolitan independent coffee shops by Random Forests model.

Independent coffee shops are the alternative workplaces for people working remotely from traditional offices but are not concerned about their indoor air quality (IAQ). This study aimed to rank the environmental factors in affecting the IAQ by Random Forests (RFs) models. The indoor environments and human activities of participated independent coffee shops were observed and recorded for 3 consecutive days including weekdays and weekend during the business hours. The multi-sized particulate matter (PM), particle-bound polycyclic aromatic hydrocarbons (p-PAHs), total volatile organic compounds (TVOCs), CO, CO2, temperature and relative humidity were monitored. RFs models ranked the environmental factors. More than 20% of the 15-min average concentrations of PM10, PM2.5, and CO2 exceeded the World Health Organization guidelines. Occupant density affected TVOCs, p-PAHs and CO2 concentrations directly. Tobacco smoking dominated PM10, PM2.5, TVOCs and p-PAHs concentrations mostly. CO concentration was affected by roasting bean first and tobacco smoking secondly. The non-linear relationships between temperature and these pollutants illustrated the relative low concentrations happened at temperature between 22 and 24 °C. Tobacco smoking, roasting beans and occupant density are the observable activities to alert the IAQ change. Decreasing CO2 and optimizing the room temperature could also be the surrogate parameters to assure the IAQ.

The impacts of ambient relative humidity and temperature on supine position-related obstructive sleep apnea in adults.

Obstructive sleep apnea (OSA) is associated with seasonal variations. The objective of this study was to examine associations of ambient relative humidity (RH) and temperature on sleep parameters. We conducted a cross-sectional study by retrospectively recruiting 5204 adults from a sleep center in Taipei, Taiwan. Associations of 1-night polysomnography with ambient RH and temperature in 1-day, 7-day, 1-month, 6-month, and 1-year averages were examined using linear regression models and a mediation analysis. RH increase was associated with snoring index decrease and apnea/hypopnea index (AHI) increase. Temperature increase was associated with decreases in sleep efficiency and the AHI, and increases in the wake time after sleep onset and snoring index. RH increase was inversely associated with non-rapid eye movement (NREM) sleep stage I (N1), III (N3), and rapid eye movement (REM) sleep, but positively associated with the NREM sleep stage II (N2) stage. Temperature increase was associated with N1, N2, and N3 sleep. An increase in RH was associated with an increase in the arousal index and a decrease in the < 95% arterial oxygen saturation (SaO2) among total, REM, and NREM sleep, whereas a temperature increase was associated with a decrease in the arousal index and an increase in < 95% SaO2 among total, REM, and NREM sleep. An increase in RH was associated with increases in the time spent in a supine posture and the supine AHI. An increase in temperature was associated with decreases in the supine posture, supine AHI, and non-supine AHI. The N3 sleep stage was an important mediator in increasing the supine AHI with a long-term increase in RH. But the N1 and N2 sleep stages mediated a decrease in the supine AHI with an increase in RH. In conclusion, ambient RH and temperature were associated with alterations in sleep parameters in adults, which were mediated by the sleep cycle. An understanding of outdoor environments has important implications for diagnostic classifications in the supine dominance of OSA in adults.

Association of long-term indoor exposure to fine particles with pulmonary effects in Northern Taiwan.

An association between short-term indoor exposure to fine particles (PM2.5) and acute respiratory effects has been reported. It is still unclear whether long-term indoor exposure to PM2.5 is associated with pulmonary events. This study recruited 1023 healthy adult homeworkers to conduct a prospective observational study from 2010 to 2021. Four repeated home visits per year were conducted for each participant to measure 24-hour PM2.5 and peak expiratory flow rate (PEFR) and to collect blood samples for absolute eosinophil count (AEC) and carcinoembryonic antigen (CEA) analysis. Additionally, a questionnaire related to personal characteristics, health status and home characteristics was conducted for each participant. The mixed-effects models showed a significant association of PM2.5 with increased CEA and AEC and decreased % predicted PEFR. No significant association between low-level PM2.5 exposure (10-year mean level < 10 µg/m3) and adverse pulmonary effects was observed. The present study concluded that long-term indoor exposure to PM2.5 at a concentration higher than 10 µg/m3 was associated with adverse pulmonary effects among healthy adult homeworkers.

Synthesis and evaluation of 2-(2'-((dimethylamino)methyl)-4'-(2-fluoroethoxy-substituted)phenylthio)benzenamine derivatives as potential positron emission tomography imaging agents for serotonin transporters.

A series of diphenylsulfide derivatives with various substitutions at the 4-position on phenyl ring A and different lengths of the 2-fluoroethoxy-substituted side-chain at the 4'-position on ring B were synthesized and evaluated as potential positron emission tomography (PET) imaging agents for serotonin transporters (SERT). These ligands exhibited high SERT binding affinities (Ki = 0.11-1.3 nM) and the 4-methyl-substituted (4-Me) compounds 7a and 8a displayed excellent selectivity for SERT versus norepinephrine transporters (NET) (392- and 700-fold, respectively). In the parallel artificial membrane permeability assay (PAMPA), these ligands demonstrated moderate to high brain penetration, and the 4-Me analogs showed higher BBB permeability than the corresponding 4-F analogs. The 2-fluoroethoxy-substituted ligands showed higher metabolic stability and lower lipophilicity than 4-F-ADAM. [18F]7a-c were readily prepared using an automatic synthesizer and exhibited significant uptake and slow washout in rat brains. At 120 min after iv injection, [18F]7a exhibited the highest uptake in the midbrain, whereas [18F]7b exhibited the highest uptake in the hypothalamus and midbrain. After treatment with citalopram, a SERT-selective ligand, the uptake of [18F]7a in the hypothalamus and striatum was significantly decreased. The potent and highly selective SERT binding and the selective and reversible accumulation in SERT-rich brain regions suggested that [18F]7a is a promising lead for the further development of novel [18F]-labeled PET imaging agents for SERT binding sites in the brain.

Effects of Personal Exposures to Micro- and Nano-Particulate Matter, Black Carbon, Particle-Bound Polycyclic Aromatic Hydrocarbons, and Carbon Monoxide on Heart Rate Variability in a Panel of Healthy Older Subjects.

As a non-invasive method, heart rate variability (HRV) has been widely used to study cardiovascular autonomous control. Environmental epidemiological studies indicated that the increase in an average concentration of particulate matter (PM) would result in a decrease in HRV, which was related to the increase of cardiovascular mortality in patients with myocardial infarction and the general population. With rapid economic and social development in Asia, how air pollutants, such as PM of different sizes and their components, affect the cardiovascular health of older people, still need to be further explored. The current study includes a 72 h personal exposure monitoring of seven healthy older people who lived in the Taipei metropolitan area. Mobile equipment, a portable electrocardiogram recorder, and the generalized additive mixed model (GAMM) were adopted to evaluate how HRV indices were affected by size-fractionated PM, particle-bound polycyclic aromatic hydrocarbons (p-PAHs), black carbon (BC), and carbon monoxide (CO). Other related confounding factors, such as age, sex, body mass index (BMI), temperature, relative humidity (RH), time, and monitoring week were controlled by fixed effects of the GAMM. Statistical analyses of multi-pollutant models showed that PM2.5-10, PM1, and nanoparticle (NP) could cause heart rate (HR), time-domain indices, and frequency-domain indices to rise; PM1-2.5 and BC would cause the frequency-domain index to rise; p-PAHs would cause HR to rise, and CO would cause time-domain index and frequency-domain index to decline. In addition, the moving average time all fell after one hour and might appear at 8 h in HRVs' largest percentage change caused by each pollutant, results of which suggested that size-fractionated PM, p-PAHs, BC, and CO exposures have delayed effects on HRVs. In conclusion, the results of the study showed that the increase in personal pollutant exposure would affect cardiac autonomic control function of healthy older residents in metropolitan areas, and the susceptibility of cardiovascular effects was higher than that of healthy young people. Since the small sample size would limit the generalizability of this study, more studies with larger scale are warranted to better understand the HRV effects of simultaneous PM and other pollution exposures for subpopulation groups.

Investigation of Microenvironmental Exposures to Particle-Bound Polycyclic Aromatic Hydrocarbons for Elementary School Children.

Polycyclic aromatic hydrocarbons (PAHs) are formed when organic matters incompletely combust and get distributed into the air in the form of vapor or the particular phase of absorption or condensation on the surface of respirable particles. Certain PAHs are considered as carcinogenic and mutagenic, and are primarily associated with the particulate phase. Therefore, the characterization of exposure to particle-bound PAHs (p-PAHs) is critical to assessing the health risks in our daily life. A panel study was conducted during the years 2004 and 2005 to assess microenvironmental exposures to p-PAHs for elementary school children living in Taipei metropolitan area. During the study, integrated filter samples were collected by a dust monitor (model 1.108, Grimm) for 17 p-PAH species analysis using gas chromatography with mass spectrometry (GC/MS). The sampling durations were five days. Overall, 52 samples for children's microenvironmental exposures were included in the data analysis. Results showed that geometric mean (GM) levels (and geometric standard deviation) of p-PAH exposures were 4.443 (3.395) ng/m3 for children. The top three highest proportions of p-PAH components were indeno[1,2,3-cd]pyrene (IND) (21.7%), benzo[g,h,i]perylene (BghiP) (18.5%), and dibenz[a,h]anthracene (DBA) (9.1%), all of which are 5- or 6-ring p-PAHs. In addition, results from diagnostic ratios and principal component analysis (PCA) found that traffic pollution, incense burning, and cooking emission were the major p-PAH exposure sources for children. The total benzo[a]pyrene equivalent (BaPeq) concentration was 1.07 ± 0.80 ng/m3 (mean ± standard deviation), with a GM of 0.84 ng/m3. The GM value of the inhalation carcinogenic risk was 7.31 × 10-5 with the range of 2.23 × 10-5 to 3.11 × 10-4, which was higher than the U.S. Environmental Protection Administration guideline limit of 10-6. DBA accounted for 45.1% of the excess cancer risk, followed by benzo[a]pyrene (BaP) (33.5%) and IND (10.7%). In conclusion, the current study demonstrated that inhalational cancer risk due to the p-PAH exposures for children is not negligible, and more efficient technical and management policies should be adopted to reduce the PAH pollutant sources.

Application of land-use regression models to estimate sound pressure levels and frequency components of road traffic noise in Taichung, Taiwan.

Few studies have applied land-use regression to predict road traffic noise exposure, and there are few predictive models for different frequencies. This study aimed to measure 24-h average road traffic noise levels and to analyze the frequency components over one year to establish land-use regression models of noise exposure. Fifty monitoring stations were set up to conduct 3 measurements for A-weighted equivalent sound pressure levels over 24 h (Leq,24h) and night equivalent sound pressure levels (Lnight), as well as octave-band analyses, during the 2013-2014 period. Noise measurements were integrated with land-use types, road and traffic information, meteorological data and geographic information systems to construct land-use regression models. Leave-one-out cross-validation was performed to test the validity of the predictive models. The annual means of Leq,24h and Lnight were 66.4 ±â€¯4.7 A-weighed decibels (dBA) and 62.1 ±â€¯6.0 dBA, respectively. Octave-band frequency analyses revealed that the highest means over 24 h and at night were 61.4 ±â€¯5.3 decibels (dB) and 56.7 ±â€¯6.6 dB (both at 1000 Hz), respectively. The model-explained variance (R2) of the full-frequency noise was 0.83 for Leq,24h and 0.79 for Lnight. The R2 values for octave-band-frequency noise ranged from 0.67 to 0.88 for Leq,24h and 0.65 to 0.85 for Lnight, with the highest R2 at 250 Hz for Leq,24h and at 125 Hz for Lnight. The differences between the model R2 and the leave-one-out cross-validation R2 ranged from 5% to 15% for both Leq,24h and Lnight at all frequencies. In the validation, the root mean squared error was 2.09 dBA and 2.80 dBA for the full-frequency Leq,24 and Lnight, respectively, and ranged from 1.89 to 2.62 dB and from 2.51 to 3.28 dB for the octave-band-frequency Leq,24h and Lnight, respectively. This study observed that the annual means of the measured Leq,24h and Lnight in Taichung were both above 60 dBA and had the highest level at 1000 Hz. The developed land-use regression models of Leq,24 and Lnight both had good predictive capacity for the full frequency spectrum and within octave bands and can therefore be applied for epidemiological studies.

Microglial activation and inflammation caused by traffic-related particulate matter.

Neurotoxicity caused by particulate matter (PM) has been highlighted as being a potential risk factor for neurodegenerative diseases. However, the effects of brain inflammation in response to traffic-related PM remain unclear. The objective of this study was to investigate the effects of traffic-related PM on microglial responses. We determined the cytotoxicity, oxidative stress, lipid peroxidation, inflammation, activation, autophagy, and apoptosis due to exposure to carbon black (CB) and diesel exhaust particles (DEPs) in Bv2 microglial cells. Additionally, cells were pretreated with corticosteroid to determine alterations in microglial activation and inflammation. For in vivo confirmation, Sprague Dawley (SD) rats were whole-body exposed to traffic-related PM1 (PM with an aerodynamic diameter of <1 µm) for 3 and 6 months. We observed that a decrease in cell viability and increases in dichlorodihydrofluorescein (DCFH), lactate dehydrogenase (LDH), and thiobarbituric acid-reactive substances (TBARSs) occurred due to CB and DEP. Production of interleukin (IL)-6 and soluble tumor necrosis factor (TNF)-α was significantly stimulated by CB and DEP, whereas production of cellular TNF-α was significantly stimulated by CB. Iba1 and prostaglandin E2 (PGE2) significantly increased due to CB and DEP. Consistently, we observed significant increases in Iba1 in the hippocampus of rats after 3 and 6 months of exposure to traffic-related PM1. We found that the light chain 3II (LC3II)/LC3I ratio and caspase-3 activity increased due to CB and DEP exposure. Subsequently, LDH, TBARS, LC3II/I, and caspase-3 activities did not clearly respond to corticosteroid pretreatment followed by DEP exposure in BV2 cells. Results of the present study suggested that traffic-related PM induced cytotoxicity, lipid peroxidation, microglial activation, and inflammation as well as autophagy and caspase-3 regulation in microglia. We demonstrated that microglial activation and inflammation may play important roles in the response of the brain to traffic-related PM.

Indoor ozone levels, houseplants and peak expiratory flow rates among healthy adults in Taipei, Taiwan.

The association between houseplants and indoor air quality improvement has been reported in previous studies. However, the effect of houseplant-emitted isoprene on the association between ozone (O3) formation and respiratory health remains unclear. We recruited 60 adult subjects from 60 houses with or without houseplants (1:1) in Taipei; twelve house visits were conducted in each home throughout 2014. The indoor air pollutants that were measured consisted of particulate matter less than or equal to 2.5 µm in diameter (PM2.5), O3 and isoprene. Peak expiratory flow rate (PEFR) was measured in each study subject during each house visit. Household information was collected by a questionnaire. Mixed-effects models were used to explore the association between indoor air pollution levels and PEFR. We found that the concentrations of O3 and isoprene in houses with houseplants were higher than those in houses without houseplants. In contrast, PM2.5 levels and % predicted PEFR were higher in houses without houseplants than in those with houseplants. Moreover, increased levels of O3 and PM2.5 in houses with houseplants were associated with a decreased % predicted PEFR, especially in the summer. We concluded that increased levels of indoor O3 and PM2.5 were associated with decreased PEFR. The presence of houseplants was associated with indoor O3, isoprene and PEFR variations in the summer.

Road Traffic Noise, Air Pollutants, and the Prevalence of Cardiovascular Disease in Taichung, Taiwan.

Background: A few studies have investigated the interaction between exposure to road traffic noise, air pollutants, and cardiovascular disease (CVD), but their results were inconsistent. This cross-sectional study investigated whether road traffic noise, particulate matter with dynamic diameter less than 10 µm (PM10) and nitrogen dioxides (NO2) exposure were independently associated with the risk of CVD. Methods: We recruited 663 volunteers who had been living near main roads for more than three years in 2008. Information concerning the subjects' home addresses was combined with noise measurements at 42 locations and annual average of air pollutants from 2 monitoring stations to estimate individual exposure. Multivariate logistic regression was used to calculate the odds ratio (OR) for diagnosed CVD, adjusting for potential confounders and co-exposure. Results: Only per 5-dBA increase in road traffic noise was significantly associated with elevated risk of CVD (adjusted OR = 2.23, 95% confidence interval (CI) = 1.26⁻3.93) in the single-exposure models. Such association was aggravated (adjusted OR = 2.96, 95% CI = 1.41⁻6.23) after adjustment for total traffic and PM10 or NO2 in the two-exposure models. Conclusions: Road traffic noise exposure may be associated with the increasing prevalence of CVD. No synergistic association was observed between co-exposure to noise and air pollutants and the risk of CVD.

Effects of diesel exhaust particles on the expression of tau and autophagy proteins in human neuroblastoma cells.

Particulate air pollution is recognized as a potential risk factor for neurological disorders; however, the underlying mechanisms of neurodegenerative diseases that occur due to particulate air pollution remain unclear. The objective of the present study was to evaluate the neurotoxic effects caused by diesel exhaust particles (DEPs). We determined the ability of DEPs and carbon black (CB) to induce neurotoxicity, oxidative stress and inflammation, and to disrupt the expression of tau and autophagy proteins in human neuroblastoma IMR-32 cells. Spherical CB (dominated by C, N, and S) and DEPs (dominated by C, N, and O) in aggregates were observed using a field emission-scanning electron microscope (FE-SEM) equipped with energy-dispersive x-ray (EDX) microanalysis. Cell viability was significantly decreased by CB and DEPs in IMR-32 cells, but neither particle altered malondialdehyde (MDA) production. We observed that exposure to DEPs significantly increased 8-isoprostane and tumor necrosis factor (TNF)-α levels. Significantly increased expression of tau was induced in IMR-32 cells by DEPs but not by CB. Expression of beclin 1 was increased by DEPs, whereas the light chain 3II (LC3II)/LC3I ratio was increased by CB. Results of the present study suggested that DEPs induced neuroinflammation, oxidative stress, and neurodegenerative-related tau overexpression and regulation by autophagy in IMR-32 cells. We demonstrated that DEPs are able to induce neurotoxicity, which could be associated with the development of neurodegenerative diseases.

Nanoengineering of an Si/MnGe quantum dot superlattice for high Curie-temperature ferromagnetism.

The realization and application of spintronic devices would be dramatically advanced if room-temperature ferromagnetism could be integrated into semiconductor nanostructures, especially when compatible with mature silicon technology. Herein, we report the observation of such a system - an Si/MnGe superlattice with quantum dots well aligned in the vertical direction successfully grown by molecular beam epitaxy. Such a unique system could take full advantage of the type-II energy band structure of the Si/Ge heterostructure, which could trap the holes inside MnGe QDs, significantly enhancing the hole-mediated ferromagnetism. Magnetic measurements indeed found that the superlattice structure exhibited a Curie temperature of above 400 K. Furthermore, zero-field cooling and field cooling curves could confirm the absence of ferromagnetic compounds, such as Ge8Mn11 (Tc ∼ 270 K) and Ge3Mn5 (Tc ∼ 296 K) in our system. Magnetotransport measurement revealed a clear magnetoresistance transition from negative to positive and a pronounced anomalous Hall effect. Such a unique Si/MnGe superlattice sets a new stage for strengthening ferromagnetism due to the enhanced hole-mediation by quantum confinement, which can be exploited for realizing the room-temperature Ge-based spin field-effect transistors in the future.

Fast and Facile Synthesis of 4-Nitrophenyl 2-Azidoethylcarbamate Derivatives from N-Fmoc-Protected α-Amino Acids as Activated Building Blocks for Urea Moiety-Containing Compound Library.

A fast and facile synthesis of a series of 4-nitrophenyl 2-azidoethylcarbamate derivatives as activated urea building blocks was developed. The N-Fmoc-protected 2-aminoethyl mesylates derived from various commercially available N-Fmoc-protected α-amino acids, including those having functionalized side chains with acid-labile protective groups, were directly transformed into 4-nitrophenyl 2-azidoethylcarbamate derivatives in 1 h via a one-pot two-step reaction. These urea building blocks were utilized for the preparation of a series of urea moiety-containing mitoxantrone-amino acid conjugates in 75-92% yields and parallel solution-phase synthesis of a urea compound library consisted of 30 members in 38-70% total yields.

Enhancing electric-field control of ferromagnetism through nanoscale engineering of high-Tc MnxGe1-x nanomesh.

Voltage control of magnetism in ferromagnetic semiconductor has emerged as an appealing solution to significantly reduce the power dissipation and variability beyond current CMOS technology. However, it has been proven to be very challenging to achieve a candidate with high Curie temperature (Tc), controllable ferromagnetism and easy integration with current Si technology. Here we report the effective electric-field control of both ferromagnetism and magnetoresistance in unique MnxGe1-x nanomeshes fabricated by nanosphere lithography, in which a Tc above 400 K is demonstrated as a result of size/quantum confinement. Furthermore, by adjusting Mn doping concentration, extremely giant magnetoresistance is realized from ∼8,000% at 30 K to 75% at 300 K at 4 T, which arises from a geometrically enhanced magnetoresistance effect of the unique mesh structure. Our results may provide a paradigm for fundamentally understanding the high Tc in ferromagnetic semiconductor nanostructure and realizing electric-field control of magnetoresistance for future spintronic applications.