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Background: Chemical exposure from slime toys can cause potential health effects. Although slime toys are popular in Asia, the regulation of boron, chloromethylisothiazolinone (CMIT), and methylisothiazolinone (MIT) in these toys has been implemented only in Korea. Objective: In this study, we investigated boron migration levels and CMIT and MIT concentrations in 127 slime products from Asian cities and estimated children’s exposure to boron and the biocides in Korea. Methods: Slime boron migration levels were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES), according to Part 3 of the European Standard on the safety of toys (EN 71-3:2013). CMIT and MIT concentrations were analyzed using liquid chromatography tandem mass spectrometry (LC-MS/MS). Exposure doses of boron, CMIT, and MIT were calculated using the exposure pattern of children slime users in Korea. Results: Average boron migration levels of the slime products in Seoul, Bangkok, Hong Kong, Taipei, and Yokohama were 691.9, 851.1, 806.6, 509.0, and 956.2 mg/kg, respectively. Of the 127 slime products tested, 70.1% exceeded the EU boron migration limit of 300 mg/kg for toys made with sticky material. Boron migration levels in slime products in Korea did not differ significantly by manufacturing date, although the Korean boron regulations were enacted in January 2019. CMIT and MIT were detected from 51.2% and 36.2% of all products, respectively, and tended to be detected simultaneously. Exposure doses of boron, CMIT, and MIT were highest among infants. Significance: Oral exposure was the most important for boron exposure. It is necessary to manage boron level in slime products and minimize exposure from hand to mouth action in infants.

Forming gas annealing (FGA) in a deuterium (D2) ambient is crucial importance to MOSFET fabrication technologies related to alleviation of trap state at Si/SiO2 interface as well as oxide bulk by $D_{2}$ passivation. In this study, post-metal annealing (PMA) process with $D_{2}$ and $N_{2}$ gases under a high-pressure condition was conducted to verify performance enhancement in gate-enclosed FETs. We explored the trap behaviors inside the bandgap of Si and $SiO_{2}$ by quantitatively using capacitance-voltage ( ${C}$ – ${V}$ ) characteristics. Furthermore, the change of deuterium and nitrogen ions in Si/SiO2 gate stack before and after the PMA process was directly investigated by time-of-flight secondary ion mass spectroscopy (ToF-SIMS) depthprofiling technique.

Conductive carbon and repetitive CV cycling lead to a complete phase transition from the mixture of Mn(OH)2to Mn active phase (δ-MnO2) for oxygen evolution reaction (OER) by forming an electrically interconnected interface, which enlarges the active area of δ-MnO2for advanced OER activity.

Rapid determination method of Li-ion battery degradation using high C-rate voltage profiles proposing insights into the states of degradation modes in aged cells.

In an effort to discover a high-mobility p-type oxide, recent computational studies have focused on Sn2+-based ternary oxides. Ta2SnO6has been suggested as a potentially useful p-type material based on the prediction of simultaneously high hole mobility and a wide range of synthesis conditions over which it is the energetically favored phase. In this study, we synthesized this material epitaxially for the first time and evaluated its properties experimentally. We measured the band gap to be 2.4 eV and attempted to substitutionally dope titanium for tantalum (TiTa’) and potassium for tin (KSn’) but found that both doped and undoped films were insulating. Amorphous Ta2SnO6films were also grown via thermal atomic layer deposition (ALD) at 175 °C. Electrical characterization of the ALD-fabricated amorphous films found them to be insulating with an optical band gap of 2.24 eV. Density functional theory calculations indicate that, under MBE growth conditions, oxygen vacancies have a negative energy of formation in crystalline Ta2SnO6when the Fermi energy lies near the valence band edge. These oxygen vacancies would lead to compensation of holes generated by TiTa’or KSn’dopants, which is consistent with our observations. We conclude that the direct growth of epitaxial p-type Ta2SnO6films using MBE-accessible growth conditions is thwarted by the spontaneous formation of oxygen vacancies. While our growth conditions do not yield p-type films, we calculate that there are conditions under which Ta2SnO6is the thermodynamically stable phase and spontaneous formation of compensating defects does not occur, motivating further studies with different synthesis techniques.

Layered double hydroxides (LDHs) have attracted great consideration in electrochemical systems such as supercapacitors and water splitting due to their layered structures, flexible interlayer distances, and tunable elemental compositions. Recently, ternary LDHs have been considered as efficient materials for energy-related applications due to their superior performance as compared to binary LDHs. To optimize the composition of ternary LDHs for electrochemical applications, herein, Co-, Ni-, and Fe-based ternary LDHs (CNFLs) at different molar ratios are prepared by a facile electrodeposition method. Among them, a sample with a higher concentration of Ni (Ni-rich CNFL) exhibits a maximal specific capacity of 467 C g–1at the sweep rate of 5 mV s–1with a capacity retention of 81% after 2000 cycles. In the case of electrocatalytic activity, the Ni-rich CNFL shows an appreciable overpotential of 139 mV to reach the current density of 10 mA cm–2along with the smallest Tafel slope (46 mV dec–1). The Ni-rich CNFL shows excellent electrocatalytic stability over 8 h of stable operation. This enhanced performance of Ni-rich CNFL is attributed to the synergic effect of Co, Ni, and Fe hydroxides and the anticipated growth of more CoIVactive sites with the higher surface area. Thus, CoNiFe LDH with a high concentration of Ni acts as a potential electrode material for electrochemical applications.

In the past 20 years, there has been a growing interest in the phenomenon of workplace envy. This article provides an overarching review and analysis of the workplace envy literature. We first consider conceptual and measurement challenges facing envy researchers. We then review the current knowledge base in the research with a focus on synthesizing what we have learned regarding workplace envy's transmutations, highlighting directions for future research. We explore two relatively understudied areas in the envy literature—antecedents of envy and the experience of being envied. We discuss methodologies used in the literature to study envy and outcomes and conclude with a focus on cross-cultural and practical implications.

Mold stain remover (MSR) is used to clean mold and mildew spots from surfaces and contains a variety of chemical substances. In this study, we estimated the inhalation and dermal exposures associated with the use of trigger spray MSRs, and performed screening-level risk assessments for the use of this type of product in Korea. Inhalation and dermal exposures were estimated using exposure algorithms based on exposure factors obtained from a nationwide survey of 10,000 participants and chemical analyses of the four most popular trigger spray MSRs. The hazard quotients (HQs) for noncancer risk and excess cancer risk (ECR) were calculated for each chemical. The mean inhalation exposure estimates for formaldehyde, benzene, chloroform, and carbon tetrachloride were 6.9 × 10−7, 1.7 × 10−7, 5.4 × 10−6, and 2.7 × 10−5mg/kg/day, respectively. Dermal exposures of the chemicals were 5.7–6.5 times higher than inhalation exposures. The HQs for total exposure were all below 1, which indicated little noncancer risk from the use of MSRs. The safe ECR value of 1 × 10−6, was exceed in one subject for inhalation exposure of benzene and four subjects for dermal exposure of formaldehyde, while 19.8% for dermal exposure of benzene were above this value. Therefore, use of trigger spray MSRs in Korea should require more detailed exposure and risk assessment, especially for benzene.

Ammonia and hydrogen sulfide are harmful gases generated during aerobic/anaerobic bacterial decomposition of livestock manure. We evaluated ammonia and hydrogen sulfide concentrations generated from workplaces at livestock farms and determined environmental factors influencing the gas concentrations.

Relationships among portable scanning mobility particle sizer (P-SMPS), condensation particle counter (CPC), and surface area monitor (SAM), which are different metric measurement devices, were investigated, and two widely used research grade (RG)-SMPSs were compared to harmonize the measurement protocols.

Piezoelectricity of transition metal dichalcogenides (TMDs) under mechanical strain has been theoretically and experimentally studied. Powerful strain sensors using Schottky barrier variation in TMD/metal junctions as a result of the strain-induced lattice distortion and associated ion-charge polarization were demonstrated. However, the nearly fixed work function of metal electrodes limits the variation range of a Schottky barrier. We demonstrate a highly sensitive strain sensor using a variable Schottky barrier in a MoS2/graphene heterostructure field effect transistor (FET). The low density of states near the Dirac point in graphene allows large modulation of the graphene Fermi level and corresponding Schottky barrier in a MoS2/graphene junction by strain-induced polarized charges of MoS2. Our theoretical simulations and temperature-dependent electrical measurements show that the Schottky barrier change is maximized by placing the Fermi level of the graphene at the charge neutral (Dirac) point by applying gate voltage. As a result, the maximum Schottky barrier change (ΔΦSB) and corresponding current change ratio under 0.17% strain reach 118 meV and 978, respectively, resulting in an ultrahigh gauge factor of 575 294, which is approximately 500 times higher than that of metal/TMD junction strain sensors (1160) and 140 times higher than the conventional strain sensors (4036). The ultrahigh sensitivity of graphene/MoS2heterostructure FETs can be developed for next-generation electronic and mechanical–electronic devices.

It is generally recognized that most nosocomial infections are spread by exposure to expelled particles at close range (usually within 1 m) or through contact. Although the Korea Centers for Disease Control established a 2-m cut-off for transmittance from patients during the Middle East Respiratory Syndrome (MERS) outbreak in Korea in 2015, questions have been raised regarding possible infection due to aerosols transported beyond this distance. The aim of this study was to characterize cough-generated aerosol emissions from cold patients and to determine the transmission distance of cough particles in indoor air. The study was conducted using subjects with acute upper respiratory infections. The number and size distribution of the particles generated from each cough were measured after participants coughed into a stainless steel chamber in a clean room. The total particle concentration was measured for each subject in the near field (< 1 m) and far field (> 2 m). The number of particles emitted by the cough of an infected patient was 560 ± 5513% greater than that generated by patients after recovery (P< 0.001). The number of particles was also significantly higher (P< 0.001) than the background concentration when infected patients were coughing, even in the far field. These results suggest that the 2-m cut-off should be reconsidered to effectively prevent airborne infections.

ABSTRACTAlthough Internet cafes have been designated as nonsmoking areas in Korea, smoke-free legislation has allowed the installation of indoor smoking rooms. The purposes of this study were to determine secondhand smoke (SHS) leakage from an Internet café smoking room and to identify factors associated with SHS leakage. PM2.5(particulate matter with an aerodynamic diameter ≤2.5 μm) mass concentrations were measured simultaneously both inside and outside the door to the smoking room. During each measurement, a field technician observed how long the smoking room door was opened and closed, the direction of door opening, and the number of smokers. A multivariate linear regression model was used to identify the causality of SHS leakage from the smoking room. A time series of PM2.5concentrations both inside and outside the door to the smoking room showed a similar trend. SHS leakage was significantly increased because of factors associated with the direction of the smoking room door being opened, the duration of how long the smoking room door was opened until it was closed, and the average PM2.5concentration inside the smoking room when the door was opened. SHS leakage from inside the smoking room to outside the smoking room was evident especially when the smoking room door was opened. Since the smoking room is not effective in preventing SHS exposure, the smoking room should be removed from the facilities to protect citizens from SHS exposure through revision of the current legislation, which permits installation of a smoking room.Implications: This paper concerns secondhand smoke (SHS) leakage from indoor smoking room. Unlike previous studies, the authors statistically analyzed the causality of PM2.5concentration leakage from a smoking room using time-series analysis. Since the authors selected the most common smoking room, the outcomes could be generalized. The study demonstrated that SHS leakage from smoking room and SHS leakage were clearly associated with door opening. The finding demonstrated ineffectiveness of smoking room to protect citizens and supports removal of indoor smoking room.

People spend the majority of their time in indoor environments. Maintaining adequate indoor temperature and humidity is necessary to support health and improve quality of life. However, people with low incomes can be vulnerable because they may not be able to use effective cooling and heating systems in their homes. In this study, the indoor temperature and humidity in low-income residences over a year in Seoul, Korea was characterized. Indoor temperature and humidity were measured in three types of homes (12 rooftop residences, 16 basement residences, and 18 public rental apartments) occupied by low-income residents. Both differed significantly among the three types of residence, particularly during the summer and winter seasons. A regression model between indoor and outdoor temperature detected a heating threshold at 3.9°C for rooftop residences, 9.9°C for basement residences, and 17.1°C for public rental apartments. During tropical nights and cold-wave advisory days, rooftop residences showed the most extreme indoor temperatures. This study demonstrates that people living in rooftop residences could be at risk from extreme hot and cold conditions.

In the present work, the formation of TiO2 nanostructures by anodization was investigated. The anodic reaction was carried out in phosphate/glycerol electrolyte at high temperatures. By controlling the chemical and electrical parameters of anodization, TiO2 nanostructures with various morphologies can be formed. Additionally, chemical analysis of electrolytes provide the clue to a possible anodization reaction pathway.

Zinc oxide nanoparticle electrode catalysts were used to electrochemically examine benzene-derived compounds by controlling geometric factors (particle size and oxide-layer thickness) to measure the detection sensitivity difference. Spin-coating was performed to control the nanoparticle layer thickness. First, a representative benzene-derived compounds (2,4,6-trinitrotoluene) was detected using cyclic voltammetry. Three main cathodic reduction peaks were confirmed in the range of −0.5 to −0.9 V (vs Ag/AgCl in 3 M KCl). 50 nm diameter and ∼2 μm thickness of zinc oxide nanoparticles appeared the best detection performance, due to the surface uniformity, high surface area, and electric conductivity. Two additional benzene-derived compounds (2,4-dinitrotoluene and diphenylamine) were utilized to measure the detectability of the zinc oxide nanoparticle layers. Consequently, 2,4-dinitrotoluene and diphenylamine were detected using cyclic voltammetry. The mass transfer of these three benzene-derived compounds affected the diffusion- and surface-controlled processes. Finally, the limits of detection, quantitation, and sensitivity of the benzene-derived compounds were recorded using differential pulse voltammetry. The results indicated that adjusting the geometric factor is a competitive method for enhancing the detection sensitivity. Moreover, this work can be extended to detect diverse benzene-derived compounds such as diazonitrophenol, nitrocellulose, picric acid, and tetryl.

Hematite, α-Fe2O3, is considered as one of the most promising materials for sustainable hydrogen production viaphotoelectrochemical water splitting with a theoretical solar-to-hydrogen efficiency of 17%. However, the poor electrical conductivity of hematite is a substantial limitation reducing its efficiency in real experimental conditions. Despite of computing models suggesting that the electrical conductivity is extremely anisotropic, revealing up to 4 orders of magnitude higher electron transport with conduction along the (110) hematite crystal plane, synthetic approaches allowing the sole growth in that direction have not been reported yet. Here, we present a strategy for controlling the crystal orientation of very thin hematite films by adjusting energy of ion flux during advanced pulsed reactive magnetron sputtering technique. The texture and effect of the deposition mode on the film properties were monitored by XRD, conversion electron Mössbauer spectroscopy, XPS, SEM, AFM, PEC water splitting, IPCE, transient photocurrent measurements, and Mott–Schottky analysis. The precise control of the synthetic conditions allowed to fabricate hematite photoanodes exhibiting fully textured structures along (110) and (104) crystal planes with huge differences in photocurrents of 0.65 and 0.02 mA cm–2(both at 1.55 V versusRHE), respectively. The photocurrent registered for fully textured (110) film is among record values reported for thin planar films. Moreover, the developed fine-tuning of crystal orientation having a huge impact on the photoefficiency would induce further improvement of thin hematite films mainly if cation doping will be combined with the controllable texture.

The objective was to determine secondhand smoke (SHS) exposure with and without smoke-free laws in urban and rural communities. The research hypothesis was that SHS exposure in public places could be improved by smoke-free law regardless of urban and rural status. Indoor air quality in hospitality venues was assessed in 53 communities (16 urban and 37 rural) before smoke-free laws; 12 communities passed smoke-free laws during the study period. Real-time measurements of particulate matter with 2.5 µm aerodynamic diameter or smaller (PM2.5) were taken 657 times from 586 distinct venues; about 71 venues had both pre- and post-law measurements. Predictors of log-transformed PM2.5level were determined using multilevel modeling. With covariates of county-level percent minority population, percent with at least high school education, adult smoking rate, and venue-level smoker density, indoor air quality was associated with smoke-free policy status and venue type and their interaction. The geometric means for restaurants, bars, and other public places in communities without smoke-free policies were 22, 63, and 25 times higher than in those with smoke-free laws, respectively. Indoor air quality was not associated with urban status of venue, and none of the interactions involving urban status were significant. SHS exposure in public places did not differ by urban/rural status. Indoor air quality was associated with smoke-free law status and venue type.Implications: This study analyzed 657 measurements of indoor PM2.5level in 53 communities in Kentucky, USA. Although indoor air quality in public places was associated with smoke-free policy status and venue type, it did not differ by urban and rural status. The finding supports the idea that population in rural communities can be protected with smoke-free policy. Therefore, it is critical to implement smoke-free policy in rural communities as well as urban areas.

The level of particulate matter of less than 10 μm diameter (PM10) at subway platforms can be significantly reduced by installing a platform screen-door system. However, both workers and passengers might be exposed to higher PM10levels while the cars are within the tunnel because it is a more confined environment. This study determined the PM10levels in a subway tunnel, and identified the sources of PM10using elemental analysis and receptor modeling. Forty-four PM10samples were collected in the tunnel between the Gireum and Mia stations on Line 4 in metropolitan Seoul and analyzed using inductively coupled plasma–atomic emission spectrometry and ion chromatography. The major PM10sources were identified using positive matrix factorization (PMF). The average PM10concentration in the tunnels was 200.8 ± 22.0 μg/m3. Elemental analysis indicated that the PM10consisted of 40.4% inorganic species, 9.1% anions, 4.9% cations, and 45.6% other materials. Iron was the most abundant element, with an average concentration of 72.5 ± 10.4 μg/m3. The PM10sources characterized by PMF included rail, wheel, and brake wear (59.6%), soil combustion (17.0%), secondary aerosols (10.0%), electric cable wear (8.1%), and soil and road dust (5.4%). Internal sources comprising rail, wheel, brake, and electric cable wear made the greatest contribution to the PM10(67.7%) in tunnel air.ImplicationsWith installation of a platform screen door, PM10levels in subway tunnels were higher than those on platforms. Tunnel PM10levels exceeded 150 μg/m3of the Korean standard for subway platform. Elemental analysis of PM10in a tunnel showed that Fe was the most abundant element. Five PM10sources in tunnel were identified by positive matrix factorization. Railroad-related sources contributed 68% of PM10in the subway tunnel.

A comprehensive profile of volatile organic compounds (VOCs) in public spaces is needed for interpreting indoor air measurements. Seasonal differences in profiles are critical for epidemiological study and risk assessment. The purposes of this study were to establish profiles for individual VOCs in 50 indoor public places in Korea and to determine seasonal variations in their concentrations. Air samples were taken during working hours. Seventy-two of the 91 targeted VOCs were identified using multiple standards. Six VOCs detected in all summer and winter samples were toluene, acetone, m,p-xylenes, ethylbenzene, benzene, and styrene. In summer, methyl ethyl ketone and 1-butanol were also found in all samples. In both seasons, the dominant indoor VOCs were toluene, m,p-xylenes, ethylbenzene, acetone, and isopropyl alcohol. Other chemicals associated with gasoline emissions were dominant in summer. Limonene was dominant only in winter due to the consumption of tangerines. The nine VOCs with the highest concentrations comprised 64.8% and 49.6% of the TVOC in summer and winter, respectively. Comparing two types of adsorbent tube, a single adsorbent tube with Tenax-TA had similar detection performance as a double adsorbent tube with Tenax and Carbotrap.

There are few studies measuring exposure to outdoor tobacco smoke (OTS). Tobacco users often gather at the boundaries of tobacco-free campuses, resulting in unintended consequences. The objective of this study was to measure exposure levels from OTS on sidewalks bordering a tobacco-free university campus. Data were collected while walking along a sidewalk adjacent to a medium traffic road between May and August 2011. Monitoring occurred during “background,” “stop,” and “walk-through” conditions at and near hot spot area to measure fine particulate matter (<2.5 μm; PM2.5) from OTS using a portable aerosol monitor. The average PM2.5levels during stop and walk-through conditions were significantly higher than during background conditions. PM2.5peak occurrence rate and magnitude of peak concentration were significantly different depending on smoking occurrence. The peak occurrence rate during the stop condition was 10.4 times higher than during the background condition, and 3.1 times higher than during the walk-through condition. Average peak PM2.5concentrations during the stop condition were 48.7% higher than during the background condition. In conclusion, individuals could be exposed to high levels of PM2.5when stopping or even passing by smokers outdoors at the perimeter of tobacco-free campuses. The design and implementation of tobacco-free campus policies need to take into account the unintended consequences of OTS exposure at the boundaries.Implications:In this study, outdoor tobacco smoke (OTS) exposure was measured at the perimeter of tobacco-free campus. OTS exposure could be determined by peak analysis. Peak occurrence rate and peak concentration for OTS exposure were identified by using peak analysis. People could be exposed to high levels of PM2.5when standing or even passing by smokers at the perimeter of tobacco-free campus. OTS exposure measurement in other outdoor locations with smokers is needed to support outdoor smoking regulation.

In the present work, we investigate the performance of anodic TiO2nanotube layers in dye-sensitized solar cells under front- and back-side illumination configurations. To fabricate transparent TiO2nanotube electrodes, we evaporated 5 μm thick metallic Ti layers on FTO glassthen the metal layers are completely anodized to form aligned nanotube layers. We compare different types of FTO glass (conductivity and transparency) and use them for working electrodes as well as transparent platinized counter electrodes. The results show that for TiO2nanotube electrodes the resulting light conversion efficiency in DSSCs is highly affected by the type of glass used (efficiency rangedepending on configuration from 4.62% to 7.58%).

Free microvascular head and neck reconstruction requires minimal complication and safety. However, clinical observation of the wound in head and neck area is very difficult because of its narrow and inaccessible anatomy. Serum C-reactive protein (CRP) level is commonly used as a marker of acute inflammatory response and quantitative test that shows predictable kinetics. Therefore, awareness of natural CRP trend of free microvascular head and neck reconstruction may help in the early diagnosis of postoperative complications. The goal of this study is to describe the time course of serum CRP level and prove the usefulness of CRP as a predictor of postoperative flap wound complication after performing free microvascular reconstruction in head and neck area.

The facilitation of charge transport toward the targeted chemical reaction is a challenging task for two-dimensional (2D) nanomaterials. We demonstrate the effectiveness of two different strategies, non-metal doping and heterojunction formation, to adjust the electronic and molecular structures of g-C3N4nanosheets (CN), which could widen the visible-light response and improve the photo-induced electron–hole separation. The g-C3N4nanosheets containing impurity levels (boron doping (BCN)) were prepared by a high-temperature solid-state reaction. Additionally, by anchoring the 3D dichalcogenide structures (CdIn2S4) elicited by a wet chemical route, hybrid BCN/CdIn2S4nanostructures were obtained. The resulting BCN/CdIn2S4(BCN–CIS3) nanostructures exhibited an excellent degradation efficiency (95%) for methyl orange (MO) compared to pristine g-C3N4nanosheets (CN) (28%) and boron-doped g-C3N4(BCN) (35%). All the optimized photocatalysts were thoroughly characterized using various techniques and investigated for comparative structural, optical, morphological, and catalytic properties. Our results reveal that introducing boron atoms into the lattice of g-C3N4nanosheets leads to reduction in the band-gap energy and rapid electron transfer. The formation of heterojunctions with the 3D CdIn2S4further assists in improving the degradation efficiency by minimizing the undesired electron–hole recombination, as confirmed by time-resolved photoluminescence (TRPL) analysis. This work proposes feasible strategies and their synergy to develop innovative materials for sustainable energy conversion and environmental remediation applications.

Since the Surgeon General's groundbreaking report of 1964, “Smoking and Health,” the medical and scientific communities have uncovered the devastating effects of tobacco smoke on health. in reaction to these findings, local and state governments have enacted a variety of clean air acts to prevent unnecessary exposure to this known carcinogen. the Nevada Clean Indoor Air Act (NCIAA), a non-comprehensive smoke-free law, permits smoking in designated areas of casinos, bars, and taverns. With many Las Vegas casinos catering to all ages, this study was designed to evaluate the efficacy of NCIAA in protecting children from second hand smoke exposure. Using a device that measures ambient air particle matter concentrations, this study sampled the air quality in 15 casino gaming areas and corresponding non-smoking, children-friendly areas. the results indicate that current policy fails to preserve indoor air quality in these children-friendly areas. Furthermore, this research suggests the adoption of a more comprehensive, 100% smoke-free policy as the only effective remedy.

Electronic cigarettes (e-cigarettes) use a heating element to vaporize nicotine and other ingredients, simulating the visual, sensory, and behavioral aspects of smoking without the combustion of tobacco. An ever-growing number of companies around the world manufacture a wide variety of e-cigarette brands, despite scant information on the safety of the ingredients for human inhalation. This article provides an overview of the history, production, and marketing of e-cigarettes, the contents of e-cigarettes and vapor, how they are used, public health concerns, and implications for nursing practice, research, and policy development.

Farm workers and residential communities adjacent to agricultural fields can be exposed to soil dust generated during field operations at levels that could result in respiratory problems. However, field sampling of agricultural dust faces logistical problems from spatial and temporal differences in soil properties, field operations, and meteorological conditions. To minimize these problems, we designed a dust generator that simulates dust generation during tilling of agricultural fields to provide samples of particulate matter derived from bulk soil and developed optimal operating conditions to assure reproducible results. The dust generator consisted of a rotating chamber, where soil samples were loaded and tumbled, and a settling chamber, where airborne soil dust samples were collected using particle size–selective samplers. The following operating conditions for dust generation were evaluated: initial soil mass, air intake, rotation speed, and sampling time to optimize dust sampling. We compared the laboratory‐generated dust from soil samples with field dust that we collected from the same plots during agricultural operations. We determined from X‐ray diffraction and energy‐dispersive X‐ray analyses that the mineralogy and chemical composition of field‐ and laboratory‐generated dust were similar, indicating that the apparatus reasonably simulated field mechanical processes that produce airborne particulate matter from soils. The results suggest that the laboratory dust generator provides reliable samples of soil‐derived dust and could be useful for future studies involving airborne particulate material from soils.

AbstractIn-vehicle exposures to particulate matter (PM) and black carbon (BC) can be a significant part of personal total exposure. The purpose of this study was to identify determinants of the in-vehicle pollutant level. This study measured in-vehicle exposure to PM number concentrations using an aerosol spectrometer and BC concentration by an aethalometer. The measurement was repeated 3 times a day for 13 consecutive days in May 2007 while a vehicle was driven on a 1-hr predetermined route in Lexington, KY. The vehicle’s windows were closed, its fan was operated at the lowest setting, and air conditioning and heating were off. The average speed of all runs was 37 ± 5.8 km/hr. Arithmetic mean PM1(particle sizes ±1 μm in aerodynamic diameter) number and BC concentrations were 286 #/cm3(morning, 302 #/cm3; afternoon, 270 #/cm3; evening, 287 #/cm3) and 1.9 μg/m3(morning, 2.5 μg/m3; afternoon, 1.6 μg/m3; evening, 1.5 μg/m3), respectively. Average PM and BC concentrations increased during weekdays and decreased during weekends, and PM1number and BC concentrations were highest in the morning. Particle size distribution for PM1did not differ with time of day, but the concentration of PM1-10(particle sizes between 1 and 10 μm in aerodynamic diameter) was higher in the evening and lower in the morning. Peak PM1number concentrations were observed when the test vehicle approached busy crossroads. In-vehicle PM and BC concentrations were associated with time of the day and location, whereas the in-vehicle 1-hr PM number concentrations were closely associated with distant ambient PM2.5(particle sizes ±2.5 μm in aerodynamic diameter) concentrations measured at a stationary monitoring site. The findings suggested that in-vehicle exposure is associated with surrounding traffic.

No Abstract

Mikroelektronische Bauelemente der Zukunft könnten nicht mehr allein die Ladung des Elektrons als Informationsträger nutzen, sondern auch seinen Spin. Eine solche Spintronik würde die näher rückende Grenze der Miniaturisierung durchbrechen, die der konventionellen Mikroelektronik bei sehr kleinen Strukturen wegen unerwünschter Quanteneffekte und Wärmeleitungsproblemen droht. Die Spintronik ermöglicht zudem Bauelemente mit völlig neuen Funktionen. Dazu zählt die SpinLeuchtdiode, die zirkular polarisiertes Licht emittiert. Die große Herausforderung ist allerdings eine effektive Injektion spinpolarisierter Elektronen in etablierte Halbleitermaterialien. Dazu können diese mit verdünnten magnetischen Halbleitern kombiniert werden. Die Alternative ist die Kombination eines magnetischen Metalls mit einem Halbleitermaterial. Dieser Weg scheint derzeit schneller zur technisch realisierten Spintronik zu führen.

AbstractAn ozone (O3) exposure study was conducted in Nashville, TN, using passive O3samplers to measure six weekly outdoor, indoor, and personal O3exposure estimates for a group of 10- to 12-yr-old elementary school children. Thirty-six children from two Nashville area communities (Inglewood and Hendersonville) participated in the O3sampling program, and 99 children provided additional time-activity information by telephone interview. By design, this study coincided with the 1994 Nashville/Middle Tennessee Ozone Study conducted by the Southern Oxidants Study, which provided enhanced continuous ambient O3monitoring across the Nashville area. Passive sampling estimated weekly average outdoor O3concentrations from 0.011 to 0.030 ppm in the urban Inglewood community and from 0.015 to 0.042 ppm in suburban Hendersonville. The maximum 1- and 8-hr ambient concentrations encountered at the Hendersonville continuous monitor exceeded the levels of the 1- and 8-hr metrics for the O3National Ambient Air Quality Standard. Weekly average personal O3exposures ranged from 0.0013 to 0.0064 ppm (7-31% of outdoor levels). Personal O3exposures reflected the proportional amount of time spent in indoor and outdoor environments. Air-conditioned homes displayed very low indoor O3concentrations, and homes using open windows and fans for ventilation displayed much higher concentrations.

Chronic exposure is often assessed using a single measurement per individual or group. However, daily levels of personal exposure can vary greatly. Chronic exposure classification by a single measurement could be significantly affected by the interpersonal and daily variations of exposures. The purpose of this study is to determine the effect of using a single personal exposure measurement on estimating long-term exposure. This study used measurements of consecutive 14 daily personal exposures to nitrogen dioxide (NO2) and sulfur dioxide (SO2) of 50 individuals in Yeochun, Korea. The daily personal exposures were measured by passive samplers. Personal exposure to NO2was associated with gas cooking, and personal exposure to SO2was associated with ambient air pollution. Mixed effects models indicated that daily variability was greater than interpersonal variability for both the pollutants. Effectiveness of using single-day personal measurements for long-term population mean exposure was supported by relatively consistent daily population averages, but multiple-day measurements might be warranted for characterizing individual exposures or high-end population exposures such as the 95th percentile. Although classification of high and low exposure groups by 1-day exposure and by 14-day exposure produced similar group totals, 20% of individual NO2exposures and 31% of individual SO2exposures were misclassified using 1-day exposures. Average values of 1-day exposure and 14-day exposure were significantly different, but the difference decreased by an increase in the number of measurements for the short-term exposure. The findings were similar for both NO2and SO2, although the two air pollutants have different sources and behaviors.Journal of Exposure Analysis and Environmental Epidemiology (2004) 14, 137–143. doi:10.1038/sj.jea.7500304

A randomized case-controlled study was carried out to investigate for interferon alpha therapy in atopic dermatitis (AD) of Besnier's prurigo pattern with normal serum IgE and normal blood eosinophil fraction. Interferon alpha therapy was conducted on 14 non-responders to interferon gamma and subsequent thymopentin therapy among 100 atopic dermatitis patients. Eight patients who improved significantly, showed skin lesions of the Besnier's prurigo pattern with normal serum IgE and normal blood eosinophil fraction. For the randomized prospective case-controlled study, 44 patients with the above characteristics were selected. Thirteen Besnier's prurigo patients were treated with interferon alpha therapy, ten with interferon gamma, ten with thymopentin, and the remaining 11 were untreated as the control group. With interferon alpha therapy, 11 out of 13 Besnier's prurigo patients with normal IgE and normal blood eosinophil fraction improved significantly, two out of ten improved with interferon gamma therapy, and none improved with thymopentin therapy or in the untreated control group. Interferon alpha therapy was effective on AD of Besnier's prurigo pattern with normal serum IgE and normal blood eosinophil fraction. These results suggest the possibility of non-IgE-mediated AD and the heterogeneity of atopic dermatitis.

ABSTRACTIndoor and outdoor NO2concentrations were measured and compared with simultaneously measured personal exposures of 57 office workers in Brisbane, Australia. House characteristics and activity patterns were used to determine the impacts of these factors on personal exposure. Indoor NO2levels and the presence of a gas range in the home were significantly associated with personal exposure. The time-weighted average of personal exposure was estimated using NO2measurements in indoor home, indoor workplace, and outdoor home levels. The estimated personal exposures were closely correlated, but they significantly underestimated the measured personal exposures. Multiple regression analysis using other nonmeasured microenvironments indicated the importance of transportation in personal exposure models. The contribution of transportation to the error of prediction of personal exposure was confirmed in the regression analysis using the multinational study database.

ABSTRACTIn urban and suburban settings, indoor ozone exposures can represent a significant fraction of an individual's total exposure. The decay rate, one of the factors determining indoor ozone concentrations, is inadequately understood in residences. Decay rates were calculated by introducing outdoor air containing 80-160 parts per billion ozone into 43 residences and monitoring the reduction in indoor concentration as a function of time. The mean decay rate measured in the living rooms of 43 Southern California homes was 2.80 + 1.30 hr-1, with an average ozone deposition velocity of 0.049 + 0.017 cm/sec. The experimental protocol was evaluated for precision by repeating measurements in one residence on five different days, collecting 44 same-day replicate measurements, and by simultaneous measurements at two locations in six homes. Measured decay rates were significantly correlated with house type and the number of bedrooms. The observed decay rates were higher in multiple-family homes and homes with fewer than three bedrooms. Homes with higher surface-area-to-volume ratios had higher decay rates. The ratio of indoor-to-outdoor ozone concentrations in homes not using air conditioning and open windows was 68 + 18%, while the ratio of indoor-to-outdoor ozone was less than 10% for the homes with air conditioning in use.

ABSTRACTMeasurements of residual perchloroethylene (PCE), a dry-cleaning solvent associated with human health effects, were made in dry-cleaned acetate cloth to enable improved characterizations of both occupational and environmental exposure. A limited sample size (25acetate cloths) was used to explore the extent of inter-dry-cleaner variability in residual PCE and to characterize the effect of the pressing operation on residual PCE. A new method, which uses carbon-disulfide as the direct extracting agent, proved effective in the analysis of residual PCE, with a recovery-efficiency ≈ 75%. Inter-dry-cleaner variability of residual PCE, although marginally statistically significant, was relatively low, showing only a fourfold range compared to a 5-order-of-magnitude range obtained from Kawauchi and Nishiyama1. Pairwise comparison of residual PCE in nonpressed versus pressed acetate samples revealed a statistically significant reduction (p < 0.008), which amounted to a consistent (among dry-cleaners) pressing-related removal efficiency of 75 ± 4%. A preliminary assessment of the source term associated with the pressing operation (mass PCE liberated per kg cloth dry-cleaned, SPCE≈ 30 mg/kg) indicates a minor contribution to the average ambient air concentrations within dry-cleaning establishments.

Airborne contaminants can create hazardous conditions in confined spaces (CS) across a broad range of concentrations, e.g., from relatively low, potentially toxic levels (ppm) to much higher levels (%) causing oxygen deficiency. This study investigated ventilation characteristics for isobutylene (IBE) at relatively low concentrations, simulating toxic levels. Experimental data were compared to results from previous studies of oxygen deficiency. Data were obtained at several locations in a cubical CS model, with several variable test parameters: ventilation mode (exhaust and supply), volume flow rate (“air changes” per hour), and ventilation inlet/outlet elevation (% of model height). Findings indicated similar ventilation characteristics, in general, for simulated toxic (IBE) levels compared to oxygen deficiency. Both IBE and O2 deficiency data have shown that supply ventilation is typically more effective than exhaust and that CS locations aligned with supply outlets experience much more rapid contaminant reduction than do other locations. The data suggest that highly accurate predictions of ventilation characteristics cannot be expected for all cases with widely different contaminants and concentrations. Findings from this study indicate that ventilation guidelines for one range of contaminant concentration (e.g., causing oxygen deficiency) can be extended reasonably to encompass a broader range of concentration (e.g., to include toxic or flammable atmospheres).

ABSTRACTAn international survey of nitrogen dioxide (NO2) levels inside indoor ice skating facilities was conducted. One-week average NO2concentrations were measured inside and outside of 332 ice rinks located in nine countries. Each rink manager also completed a questionnaire describing the building, the resurfacing machines, and their use patterns. The (arithmetic) mean NO2level for all rinks in the study was 228 ppb, with a range of 1–2,680 ppb, based on a sample collected at breathing height and adjacent to the ice surface. The mean of the second indoor sample (collected at a spectator’s area) was 221 ppb, with a range of 1–3,175 ppb. The ratio of the indoor to outdoor NO2concentrations was above 1 for 95% of the rinks sampled, indicating the presence of an indoor NO2source (mean indoor:outdoor ratio = 20). Estimates of short-term NO2concentrations indicated that as many as 40% of the sampled rinks would have exceeded the World Health Organization 1-hour guideline value of 213 ppb NO2for indoor air.Statistically significant associations were observed between NO2levels and the type of fuel used to power the resurfacer, the absence of a catalytic converter on a resurfacer, and the use of an ice edger. There were also indications that decreased use of mechanical ventilation, increased number of resurfacing operations per day, and smaller rink volumes were associated with increased NO2levels. In rinks where the main resurfacer was powered by propane, the NO2concentrations were higher than in those with gasoline-powered resurfacers, while the latter had NO2concentrations higher than in those using diesel. Rinks where the main resurfacer was electric had the lowest indoor NO2concentrations, similar to the levels measured outdoor

ABSTRACTMany epidemiological studies have used house characteristics associated with indoor sources as simplified proxies for personal nitrogen dioxide (NO2) exposure. Stove type and presence of a pilot light have often been used as the two key characteristics, but significant overlaps have remained in the NO2concentrations in the exposed and unexposed groups. This has contributed to inconsistencies in epidemiological findings, due to potential misclassification of exposure. In this study, other possible proxies were analyzed by cross-table analyses and were investigated in terms of improvements in both classification and predictive power. Adding building type to the above two proxies resulted in 0–5% of households with concentrations overlapping the observed range for the opposing stratum, compared with 22–42% for the two-proxy model. In spite of this performance, the predictive power of regression models for indoor NO2was not improved by the addition of the third proxy, and the potential sample population was significantly limited. Using these analytical methods to choose descriptive proxies and evaluate the tradeoffs in their implementation can help epidemiological studies improve their designs and therefore optimize the robustness of their conclusions.

Exposures to carbon monoxide (CO) and nitrogen dioxide (NO2) were determined in seven enclosed ice skating rinks and an outdoor rink. The uptake of CO was also determined by the difference in alveolar CO concentration of the non-smoking hockey players before and after games. Carbon monoxide concentrations in enclosed rinks ranged from 4 to 117 ppm and NO2 concentrations from 342 to 2729 ppb for 2 h hockey games. The CO uptakes were linearly related to the ambient CO concentrations. Alveolar CO of the hockey players increased on average by 0.53 ppm per 1 ppm CO exposure over 2 h. Considering the CO and NO2 levels currently measured in enclosed ice skating rinks, indoor air quality guidelines or standards should be established. It is recommended that 1 h maximum allowable limits of 20 ppm CO and 250 ppb NO2 be established.

ABSTRACTThe effectiveness of a new emission control system in the ice resurfacer was tested in an exhaust gas emission laboratory, and the improvement of the air quality in a small, enclosed ice arena was demonstrated in a 4.5-month follow-up study. The emission control system consisted of a lambda sensor-controlled fuel supply and a three-way metallic catalyst that were applied to a propane-fueled resurfacer. In the laboratory tests, the engine emissions of carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NO ) reduced simultaneously by 91, 90, and 96%, respectively. During the air quality follow-up the median 1-hour average nitrogen dioxide (N02) concentration inside the ice arena decreased from 430 ug/m3(230ppb) to 58 ug/m3(31 ppb), and that of CO decreased from 4.4 mg/m3(3.8 ppm) to 1.5 mg/m3(1.3 ppm). The new emission control system proved to be a feasible, reliable, and effective means to improve the indoor air quality in the ice arena. However, continuous mechanical ventilation was necessary during all business hours in order to achieve and maintain a fully acceptable air quality with this technology.

The present work demonstrates the anodic formation of ZnF2-ZnO nanosphere layers by anodization of a zinc substrate in a fluoride containing 2-methyl-1,3-propandiol electrolyte at the substrate temperature ranging from [?]2degC to [?]30degC. The anodically grown films were characterized using FE-SEM, EDX, XPS and XRD techniques. Thermal oxidation of the film at 300degC leads to the conversion of all ZnF2 into crystalline ZnO, together with the partial fusion of nanospheres and expansion of the grains. The electrical resistance of the films was found to depend on fluoride content and crystallinity.

•New synthesis approach was developed for nanoporous carbon derived from MIP.•The developed porous carbons are promising for pre- and post-combustion CO2capture•The carbon adsorbent stored 22.1 mmol g−1and 3 mmol g−1of CO2at 25 bar and 1 bar,•Higher O-content in porous carbon attributed to remarkable selective capture of CO2over H2,N2and CH4gases.•The porosity and morphological properties of carbon are interesting for various industrial applications.

In the present work we grow TiO2 nanosponge structures by anodizing Ti in a glycerol/water/NH4F electrolyte to thickness of some um. We evaluate the photoelectrochemical behavior (bandgap, photocurrent-voltage characteristics) in presence and absence of methanol. Methanol drastically affects the photoresponse (due to hole capture and current doubling). The optimum thickness for photoelectrochemical applications of these nanostructures is dependent on the excitation wavelength. For applications such as solar light water splitting, anodic sponge structure of [?]500 nm thickness can be beneficially used to increase the photoresponse compared to compact TiO2 layers.

In the present work, we show the feasibility to grow highly ordered anodic Nb2O5 nanochannel structures from a thin Nb-layer on conducting glass (fluorine doped tin oxide, FTO). This is achieved using a glycerol-phosphate electrolyte at 180degC and a suitable anodization voltage that allows a rapid and complete conversion of the entire metallic layer into a transparent oxide layer of an extremely well defined directional nature with 20-30 nm wide open vertical channels. These layers can be used, either in the amorphous state or after thermal crystallization, for efficient reversible electrochromic switching devices.

•Preparation of Ce doped α-Co(OH)2thin film electrodes via inexpensive electrodeposition method for supercapacitor.•Effect of Ce doping on structural, morphological and supercapacitive properties on α-Co(OH)2thin films has been investigated.•Implementation of step potential electrochemical spectroscopy for the deconvolution of capacitive and diffusion controlled contributions of doped and undoped α-Co(OH)2film electrode.•Asymmetric CHCe1//AC supercapacitor demonstrates specific energy of 14 Wh kg−1at the specific power of 500 W kg−1.