Ti-containing NPs in raw water and their removal with conventional treatments in four water treatment plants in Taiwan.

The ingestion of Ti-containing nanoparticles from drinking water has emerged as a concern in recent years. This study therefore aimed to characterize Ti-containing nanoparticles in water samples collected from four water treatment plants in Taiwan and to explore the challenges associated with measuring them at low levels using single particle-inductively coupled plasma mass spectrometry. Additionally, the study sought to identify the most effective processes for the removal of Ti-containing nanoparticles. For each water treatment plant, two water samples were collected from raw water, sedimentation effluent, filtration effluent, and finished water, respectively. Results revealed that Ti-containing nanoparticles in raw water, with levels at 8.69 µg/L and 296.8 × 103 particles/L, were removed by approximately 35% and 98%, respectively, in terms of mass concentration and particle number concentration, primarily through flocculation and sedimentation processes. The largest most frequent nanoparticle size in raw water (112.0 ± 2.8 nm) was effectively reduced to 62.0 ± 0.7 nm in finished water, while nanoparticles in the size range of 50-70 nm showed limited changes. Anthracite was identified as a necessary component in the filter beds to further improve removal efficiency at the filtration unit. Moreover, the most frequent sizes of Ti-containing nanoparticles were found to be influenced by salinity. Insights into the challenges associated with measuring low-level Ti-containing nanoparticles in aqueous samples provide valuable information for future research and management of water treatment processes, thereby safeguarding human health.

Impact of age on the postural stability measured by a virtual reality tracker-based posturography and a pressure platform system.

BACKGROUND: Center of pressure (CoP) parameters are commonly used to evaluate age-related changes in postural control during standing. However, they mainly reflect ankle strategies and provide limited information about hip strategies, which are essential for postural control among the aged population. Body displacement at the lumbar level (LD) can be used as a proxy for hip strategies. OBJECTIVES: We set up a virtual reality tracker-based posturography to measure LD and compared the CoP and LD parameters in two age groups to explore the roles of ankle and hip strategies during bipedal stance. METHODS: Twenty-seven older healthy participants (63.8 ± 7.1 years old) and 27 younger controls (31.7 ± 9.9 years old) performed four standing tasks with their postural steadiness measured simultaneously with both systems under four stance conditions (combination of eyes-open/eyes-closed and wide-based/narrow-based). Five parameters were calculated from the trajectories of the CoP and LD. The difference in the parameters between two groups was analyzed with the Mann-Whitney U test. The discriminative ability of the parameters from the two systems was computed by the receiver operating characteristic curve analysis and area under the curve (AUC). We also used the intraclass correlation coefficient (ICC) to assess the correlation between two measures. RESULTS: Most of the parameters obtained from both systems were significantly different between the younger and older groups. Mean velocity in the medial-lateral and anterior-posterior directions could effectively discriminate age-related changes, especially with the LD parameters. The receiver's operation curve analysis gained the largest AUC (0.85 with both systems) with mean velocity in the medial-lateral direction during narrow-based standing with eyes closed. Meanwhile, we observed a low correlation between parameters obtained from the two methods in velocity measures, with the lowest ICC in the mean velocity in the medial-lateral direction in the older group (ICC = 0.34 ~ 0.41). CONCLUSION: Both systems could differentiate age-related changes in postural steadiness, but with dissociated information about mean velocity, especially the mean velocity in the medial-lateral direction in the older group. The results support the complimentary role of using tracker-based posturography to understand the effect of age on the mechanisms of postural control.

Increased inflammation in rheumatoid arthritis patients living where farm soils contain high levels of copper.

BACKGROUND/PURPOSE: Heavy metal pollution in farm soils is a problem in some parts of Taiwan. Copper can be a factor associated with increased disease activities of rheumatoid arthritis (RA). Thus, the aim of this study was to investigate whether copper pollution in farm soils is associated with worsened RA. METHODS: Clinical parameters from 122 RA patients were collected from a medical center in central Taiwan. Levels of heavy metals in the blood were measured using inductively coupled plasma mass spectrometry. Levels of copper in farm soils were retrieved from a national survey. These data were analyzed to find the factors related to RA disease activities. RESULTS: RA patients living where farm soils contained high levels of copper had increased white blood cell counts, erythrocyte sedimentation rate, and disease activity score 28, compared with patients living where copper levels were low. Among the nine types of heavy metal measured in the study, blood levels of copper and nickel correlated with erythrocyte sedimentation rate. CONCLUSION: Our cross-sectional data suggest a correlation between RA disease activity and the level of copper at township farm soils samples. Further longitudinal studies using more rigorous methodologies are warranted to examine whether this correlation is causal.

Influence of smartphone use styles on typing performance and biomechanical exposure.

Twenty-seven subjects completed 2-min typing tasks using four typing styles: right-hand holding/typing (S-thumb) and two-hand typing at three heights (B-low, B-mid and B-high). The styles had significant effects on typing performance, neck and elbow flexion and muscle activities of the right trapezius and several muscles of the right upper limb (p < 0.0001 by repeated-measure analysis of variance). The subjects typed the fewest words (error-adjusted characters per minute: 78) with the S-thumb style. S-thumb style resulted in similar flexion angles of the neck, elbow and wrist, but significantly increased muscle activities in all tested muscles compared with the B-mid style. Holding the phone high or low reduced the flexion angles of the neck and right elbow compared with the B-mid style, but the former styles increased the muscle activity of the right trapezius. Right-hand holding/typing was not a preferable posture due to high muscle activities and slow typing speed. Practitioner Summary: Right-hand holding/typing was not favoured, due to increased muscle activities and slower typing speed. Holding the phone high or low reduced the flexion angles of the neck and right elbow, but the former styles increased the muscle activity of the right trapezius compared with holding the phone at chest level.

Long-term psychological outcome of workers after occupational injury: prevalence and risk factors.

INTRODUCTION: This study aimed to examine the prevalence rates of both post-traumatic stress disorder (PTSD) and major depression at 12 months in workers experiencing different types of occupational injury in Taiwan. Demographic and injury-related risk factors for psychological symptoms were also evaluated. METHODS: Our study candidates were injured workers in Taiwan who were hospitalized for 3 days or longer and received hospitalization benefits from the Labor Insurance program. A two-staged survey study was conducted. A self-reported questionnaire including the Brief Symptom Rating Scale and Post-traumatic Symptom Checklist was sent to workers at 12 months after injury. Those who met the criteria were recruited for the second-stage phone interview with a psychiatrist using the Mini-international Neuropsychiatric Interview (MINI). RESULTS: A total of 1,233 workers completed the questionnaire (response rate 28.0 %). Among them, 167 (13.5 %) fulfilled the criteria for the MINI interview and were invited. A total of 106 (63.5 %) completed the phone interview. The estimated rate of either PTSD/PPTSD or major depression was 5.2 %. The risk factors for psychological symptoms were female gender, lower education level, loss of consciousness after occupational injury, injury affecting physical appearance, occupational injury experience before this event, life experience before and after this injury, length of hospital stay, self-rated injury severity, and percentage of income to the family. CONCLUSIONS: These results showed that occupational injury can cause long-term psychological impact in workers. Key demographic and injury characteristics may enhance the identification of at-risk occupational injured workers who would benefit from targeted screening and early intervention efforts.

Association of blood lead and mercury with estimated GFR in herbalists after the ban of herbs containing aristolochic acids in Taiwan.

OBJECTIVE: This study was undertaken to explore the association of estimated glomerular filtration rate (GFR) with exposure to aristolochic acids (ALAs) and nephrotoxic metals in herbalists after the ban of herbs containing ALAs in Taiwan. METHODS: This cross-sectional study recruited a total of 138 herbalists without end-stage renal disease or urothelial carcinoma from the Occupational Union of Chinese Herbalists in Taiwan in 2007. Aristolochic acid I (ALA-I) was measured by ultra-high-pressure liquid chromatography/ tandem mass spectrometry (UHPLC-MS/MS) and heavy metals in blood samples were analysed by Agilent 7500C inductively coupled plasma-mass spectrometry. Renal function was assessed by using a simplified Modification of Diet in Renal Disease Study equation to estimate GFR. RESULTS: Blood lead was higher in herbal dispensing procedures (p=0.053) and in subjects who self-prescribe herbal medicine (p=0.057); mercury was also higher in subjects living in the workplace (p=0.03). Lower estimated GFR was significantly associated with lead (ß=-10.66, 95% CI -18.7 to -2.6) and mercury (ß=-12.52, 95% CI -24.3 to -0.8) with a significant interaction (p=0.01) between mercury and lead; however, estimated GFR was not significantly associated with high ALA-I level groups, arsenic and cadmium after adjusting for other confounding factors. CONCLUSIONS: We found that lower estimated GFR was associated with blood lead and mercury in herbalists after the ban of herbs containing ALAs in Taiwan. The ALA-I exposure did not show a significant negative association of estimated GFR, which might due to herbalists having known how to distinguish ALA herbs after the banning policy. Rigorous monitoring is still needed to protect herbalists and the general population who take herbs.

In utero exposure to environmental lead and manganese and neurodevelopment at 2 years of age.

BACKGROUND AND OBJECTIVE: Manganese, lead, arsenic and mercury are common neurotoxic metals in the environment. Nonetheless, the relationship between prenatal exposure to low doses of neurotoxic metals and neurodevelopment in children is not clear. The objective of this study was to explore the relationship between in utero exposure to environmental neurotoxic metals and neurodevelopment at 2 years of age. METHODS: The population of this study came from the Taiwan Birth Panel Study. We included 230 pairs of non-smoking mothers without any occupational exposure and their singleton full-term children. The information about exposure during pregnancy was obtained using a structured questionnaire, and the manganese, lead, arsenic and mercury levels in umbilical cord blood samples were analyzed using inductively coupled plasma mass spectrometry. We used the Comprehensive Developmental Inventory for Infants and Toddlers (CDIIT) to evaluate the developmental status of each child at 2 years of age, and we examined the association of in utero exposure to environmental metals and neurodevelopment using linear regression models. RESULTS: The median concentrations of manganese, lead, arsenic and mercury in the cord blood samples in this study were 47.90 µg/L (range, 17.88-106.85 µg/L), 11.41 µg/L (range 0.16-43.22 µg/L), 4.05 µg/L (range, 1.50-12.88 µg/L) and 12.17 µg/L (range, 1.53-64.87 µg/L), respectively. After adjusting for maternal age, infant gender, environmental tobacco smoke during pregnancy and after delivery, Home Observation for Measurement of the Environment Inventory results, and arsenic and mercury levels in cord blood, we found that manganese and lead levels above the 75th percentile had a significant adverse association with the overall (ß=-7.03, SE=2.65, P=0.0085), cognitive (ß=-8.19, SE=3.17, P=0.0105), and language quotients (ß=-6.81, SE=2.73, P=0.0133) of the CDIIT. CONCLUSIONS: In utero exposure to environmental manganese and lead may have an adverse association with neurodevelopment at 2 years of age, and there is an interaction effect between the manganese and lead levels in the cord blood that could aggravate the effect.

The impact of psychological symptoms on return to work in workers after occupational injury.

INTRODUCTION: This study aimed to investigate the impact of psychological symptoms on return to work (RTW) in workers after occupational injuries. METHODS: Our study candidates were injured workers who were hospitalized for 3 days or longer and received hospitalization benefits from the Labor Insurance. A self-reported questionnaire including Brief Symptom Rating Scale (BSRS-50) and RTW was sent to workers at 12 weeks after injury. At 1 year, all participants were contacted again to determine whether or not they had RTW. RESULTS: A total of 2001 workers completed the questionnaire (response rate 45.5 %) at 12 weeks after injury, among them, 1,149 had returned to work. Among the 852 who were unable to return to work at 12 weeks after injury, 225 reportedly returned to work by 1 year. A proportional hazards regression indicated that after adjusting for all possible risk factors, higher scores in BSRS-50 and BSRS-5 at 12 weeks after injury were significant risk factors for not return to work (NRTW) at 1 year after injury. Other risk factors were gender, education level, length of hospitalization, affected physical appearance, and injury type. Among 10 psycho-physiological symptoms of BSRS-50, a proportional hazards regression indicated that high score in phobic-anxiety scale was a risk factor for NRTW. CONCLUSIONS: After considering all other factors, psychological symptoms further predicted poorer probability of returning to work after occupational injury, and phobic-anxiety was the most significant symptom predicting poor RTW. Development of preventive measures among injured workers according to the risk factors identified in this study is warranted.

Temporal transition trends of cord blood lead levels in various human development index countries and in the Taipei metropolitan area.

Since low-level lead exposure is still of concern for neonates, it is worth further characterizing the temporal transition trends of cord blood lead levels (CBLLs) globally and locally in Taipei, Taiwan, after the cessation of leaded gasoline use. A literature review on CBLLs around the world was performed by searching three databanks, i.e., PubMed, Google Scholar and Web of Science, with the search keywords "cord blood" combined with "lead" or "Pb" for studies published from 1975 to May 2021. In total, 66 articles were included. Linear regressions for the reciprocal of sample size weighed CBLLs against calendar year presented a high r2 value (0.722) for the very high Human Development Index (HDI) countries and a moderate r2 value (0.308) for the combined high and medium HDI countries. The predicted CBLLs in 2030 and 2040 were 6.92 (95% CI: 6.02-7.81) µg/L and 5.85 (95% CI: 5.04-6.66) µg/L, respectively, for the very high HDI countries and 13.10 (95% CI: 7.12-19.09) µg/L and 10.63 (95% CI: 5.37-15.89) µg/L, respectively, for the combined high and medium HDI countries. To characterize the CBLL transitions in the Great Taipei metropolitan area, data from five studies conducted from 1985 to 2018 were employed. Although the results of the early four studies indicated that the Great Taipei metropolitan area did not reach the pace in CBLL reduction among the very high HDI countries, the CBLLs of the latest study during 2016-2018 were pretty low (8.1 ± 4.5 µg/L), approximately 3 years in advance of the very high HDI countries as one group to reach this low CBLL. In conclusion, further effective reduction in environmental lead exposure is challenging and must be based on the efforts from the aspects reflected by the HDI index compositions, i.e., economics, education and health, mostly implying health disparity and inequality.

Contribution of gestational exposure to ambient traffic air pollutants to fetal cord blood manganese.

Motor vehicle emissions have become a major source of air pollution. Contributions of motor vehicle emissions to exposure to toxic metals such as manganese remain inconclusive. This study investigates the relationship between the concentration of manganese in cord blood and exposure to criteria air pollutants during pregnancy. A total of 1526 mother-newborn pairs were recruited by stratified sampling between April, 2004 and July, 2005. The newborns' mothers completed questionnaires that collected information on their demographic characteristics, medical histories, and living environments. Cord blood samples were collected at birth and analyzed by inductively coupled plasma mass spectrometry for manganese. Information about criteria air pollutants which included CO, NO(2), ozone, SO(2), and PM(10) was obtained from monitoring stations run by the Taiwan Environmental Agency. Using the Arc9 Geographic Information System's kriging method, the concentration of each criteria pollutant was estimated at each newborn's residence. The geometric mean for cord blood manganese concentrations was 47.0 µg/L (GSD=1.4). After adjusting for confounding factors such as family income, maternal education, maternal smoking, alcohol drinking during pregnancy, maternal age, child gender, parity, gestational age, and birth season, the results of a multiple linear regression model indicated that cord blood manganese concentration was significantly associated with NO(2) concentration in each trimester, as well as the whole duration of gestation. Between the pregnant women exposed to the highest and those to the lowest quartile of NO(2), a 6 µg/L difference in cord blood manganese concentration was found. This finding suggests that despite other sources of manganese exposure, maternal exposure to ambient NO(2), a surrogate for traffic emission, significantly contributed to fetal cord blood manganese level. Further study is warranted to determine whether the contribution of manganese due to traffic emission causes adverse health effects in fetuses.

Does prenatal cadmium exposure affect fetal and child growth?

OBJECTIVES: Cadmium is known to be a significant health hazard, but most information comes from studies of adults. The effects of exposure to cadmium during fetal life on early growth and development remain uncertain. In this study we investigated the placental transport of cadmium and the effects of prenatal cadmium exposure on fetal and child growth in Taiwan. METHODS: The data in this study were from a birth cohort study in Taiwan which started in 2004. Pregnant women were recruited from four hospitals and interviewed after delivery to collect information on themselves and their infants. Children were followed up to obtain information on growth up to 3years of age. Whole blood cadmium concentrations in maternal and cord blood samples were measured and the relationship with birth size and growth assessed using linear regression and mixed models. RESULTS: 321 maternal blood samples and 402 cord blood samples were eligible for analysis. Among 289 pairs with maternal and cord blood suitable for measurement, the median cadmium concentration in cord blood (0.31µg/l) was less than that in maternal blood (1.05µg/l), with low correlation between the two (r=0.04). An increase in cord blood cadmium was found to be associated with newborn decreased head circumference and to be significantly and consistently associated with a decrease in height, weight and head circumference up to 3 years of age. CONCLUSIONS: Placental transport of cadmium is limited. However, prenatal cadmium exposure may have a detrimental effect on head circumference at birth and child growth in the first 3years of life.

Associations between petrol-station density and manganese and lead in the cord blood of newborns living in Taiwan.

Although the anti-knocking agents used in Taiwan do not contain manganese, there are relatively high concentrations of the element in diesel fuel. As such, there have been many concerns about the impact of exposure to diesel fuels on health. This study was conducted in Taiwan to investigate the relationship between the concentration of manganese in cord blood of Taiwanese newborns and the geographic density of petrol stations as a surrogate for determining manganese emissions from vehicular traffic. A total of 1526 full-term newborns without major congenital malformations were consecutively recruited from various medical facilities from May 2004 to July 2005. Questionnaires were completed by the newborns' mothers after delivery to collect information on demographic characteristics, medical history, living environment, and other factors. Cord blood samples were collected at birth and analyzed for manganese and lead using inductively coupled plasma mass spectrometry. The geographic density of petrol stations within a 10 km zone around each newborn's residence was calculated for 1343 newborns using the Arc9 Geographic Information System. The geometric means of cord blood manganese and lead concentrations were 47.0 µg/L (GSD=1.42) and 12.6 µg/L (GSD=1.76), respectively. After adjusting for potential confounding factors, including maternal age, and maternal education, the results of a multiple linear regression model indicated that the concentration of cord blood manganese increased monotonically with an increasing density of petrol stations. However, no such association was found for levels of lead in cord blood. Further smoothing spline model analysis indicated that a ten unit increment in petrol station density made cord blood manganese and lead levels change by factors of 1.0092 (95% CI: 1.0058, 1.0127) and 0.9994 (95% CI: 0.9890, 0.9998), respectively. This finding suggests that exposure to manganese-containing fuel from motor vehicles may result in elevated manganese levels in the fetus. Further research is warranted to explore the relationship between traffic-related manganese exposure and potential adverse effects on fetal development.

A critical exploration of blood and environmental chromium concentration among oral cancer patients in an oral cancer prevalent area of Taiwan.

The growing incidence of oral cancer (OC) in Taiwan has become a crucial public health concern. In particular, Changhua, a county in central Taiwan, carries persistently high OC incidence rate, with an alarmingly high male/female ratio of OC incidence. Previous epidemiological studies had found that the incidence is spatially correlated with the level of soil content to certain heavy metals in the central Taiwan area. Soil and the human body both intake environmental heavy metals, which can be absorbed through various ways. The soil metal concentration is an index of possible environmental exposure to heavy metal, and the blood metal concentration somewhat reflects the level of the exposure on the human body. Metallic carcinogen is likely to generate free radicals and play a role in many cancers, and many studies had reported that environmental exposure to heavy metals is an important risk factor for developing cancer. Studies on animals showed that chronic intake of chromium (Cr) could induce OC. This study aims to explore the association between the Cr concentration in the farm soil and in the blood of OC patients. We recruited 79 OC patients from Changhua County, with their lifestyle being adjusted in regression analysis. The results showed that the Cr concentration in the blood of OC patients is significantly higher than the background value, and is positively associated with the Cr concentration in the soil surrounding their residence (p-value < 0.023). Because Changhua County is only with moderate prevalence of the known OC habitual risk factors, an environmental factor related to heavy metal Cr exposure is suspected. Future investigations may verify the causal relation between Cr and OC.

Characterization of Ti-containing nanoparticles in the aquatic environment of the Tamsuei River Basin in northern Taiwan.

Titanium dioxide (TiO2) is commonly contained in many commercial products and there are concerns about its release into the aquatic environment after use. This study was designed to characterize the distribution of Ti-containing nanoparticulates (NPs) in the water of the Tamsuei River Basin in northern Taiwan. Water samples were collected from the upstream, mid-stream, and downstream areas of the Tamsuei River Basin and analyzed with single-particle ICPMS to profile the Ti-containing NPs in terms of mass concentration, number concentration and particulate size. The lowest mass concentration of Ti-containing NPs, 1.04 ± 0.04 µg/L, was found in the upstream water samples, while the highest mass concentration, 31.7 ± 0.6 µg/L, was observed in downstream samples; there was an increasing trend from upstream to downstream. The highest particulate number concentration, 479 ± 163 × 103/mL, was observed for the downstream samples, but the lowest concentration, 45.4 ± 5.6 × 103/mL, was found in the mid-stream water samples taken from Site C. Moreover, the average mode values for particulate sizes were approximately 50 nm for all samples, although a relatively larger average mode value of 62 ± 5.7 nm was observed in the mid-stream samples from Site A. Increasing mass concentrations and particulate number concentrations from upstream to downstream implied that these NPs might have originally resulted from anthropogenic activities involving the use of TiO2 NPs-containing products. Surprisingly, however, the lowest number concentrations for Ti-containing NPs in the mid-stream samples can probably be attributed to the fact that the corresponding sampling sites were located in the water preservation zone, which exhibits a particle-settling effect. Additionally, the sizes of Ti-containing NPs in downstream samples were not significantly larger than those in the upstream and mid-stream samples, as expected, which was probably due to the steric effects resulting from the presence of large amounts of macromolecule polymers in aquatic environments.

Reliability and Validity of a Virtual Reality-Based System for Evaluating Postural Stability.

Postural stability is an important indicator of balance and is commonly evaluated in neurorehabilitation. We proposed a system based on a virtual reality (HTC Vive) system with a tracker at the lumbar area. The position data of the tracker were obtained through detection of the sensors on the tracker by the VR system. The reliability and validity of these sway parameters to measure postural stability were evaluated. Twenty healthy adults had their postural sway measured with this system and a force platform system under four stance conditions, with wide- or narrow-stance and eyes open or closed. The path data from both systems were computed to obtain the following parameters: the mean distance and the mean velocity in the medial-lateral and anterior-posterior directions and the 95% confidence ellipse area. The reliability of the Vive-based sway measures was tested with intraclass correlation coefficients (ICCs). The convergent validity was tested against the center of pressure (COP) parameters from the force platform system. Finally, the discriminative validity was tested for the above four conditions. The results indicated that the Vive-based sway parameters had moderate to high reliability (ICCs: 0.56 ~ 0.90) across four conditions and correlated moderately to very highly with the COP parameters ( r = 0.420  âˆ¼  0.959 ). Bland-Altman plotting showed generally good agreement, with negative offset for the Vive-based sway parameters. The sway parameters obtained by the Vive-based system also discriminated well among the tasks. In conclusion, the results support this system as a simple and easy-to-use tool to evaluate postural stability with acceptable reliability and validity.

The Effects of Visual Backgrounds in the Virtual Environments on the Postural Stability of Standing.

A photorealistic scene in a head mount display (HMD) is considered high fidelity and associated with postural stability similar to that in the real world, but the effects of visual background under different standing conditions have not been examined. Thirty-four healthy adults performed four standing (standardized, narrow, tandem and one-leg) tasks in three scenes with an HMD, while viewing one of three scenes: a real room (real scene, RS), a photorealistic scene (VrS) and a blank scene (BS). The effects of the visual scenes and standing tasks on sway parameters were analyzed. Romberg quotients (RQs) of the sway parameters were compared between RS and VrS with reference to BS to compare visual contribution to posture stability. Sway parameters were similar during all three scenes during the standardized and narrow standing tasks, but higher in VrS and BS conditions than in the RS condition during the tandem and one-leg standing tasks. The effects of visual scenes on postural stability showed a significant interaction with the standing tasks. The BS/VsR and BS/RS ratios were close to 1.0 for the standardized and narrow standing tasks, and the magnitude of increase was lower for BS/VsR than BS/RS during the tandem and one-leg standing tasks, indicating different levels of visual dependence. The effects of virtual scenes on postural stability were task-dependent. Adjusting the amount of visual stimuli and choosing tasks with higher postural demands may result in synergic effects, but the influence of visual environments should be examined with consideration of visual targeting.

Genetic polymorphism of As3MT and delayed urinary DMA excretion after organic arsenic intake from oyster ingestion.

Organic arsenic intake from seafood is one of the major arsenic exposure routes among the general population. However, organic arsenic metabolism in the human body is not yet clear. The goal of this study was to explore the effects of genetic polymorphisms of human PNP, As3MT and GSTO1 on organic arsenic metabolism among study subjects after oyster ingestion. During the one-week dietary controlled study, fifty study subjects were provided all their daily meals without seafood, except for two designated amounts of oyster given on the fourth day. First morning voided urine samples were provided by the study subjects for 7 consecutive days and analyzed with HPLC-ICP-MS for As(3+), As(5+), monomethylarsonic acid, and dimethylarsinic acid (DMA). Blood samples were collected later for genetic polymorphisms analysis of PNP, As3MT and GSTO1. Study subjects were categorized into "fast-" (n = 32), "medium-" (n = 13) and "slow-metabolizing" (n = 5) groups based on the number of days after ingestion needed for each subject's urinary DMA level reaching peak. Allele frequencies of single nucleotide polymorphisms (SNP) in intron 6 (G/C, p = 0.024) and in intron 10 (T/C, p = 0.039) of As3MT were significantly associated with the urinary DMA excretion. General estimating equation model analysis indicated that the variants of SNP (G>C) in intron 6 and SNP (T > C) in intron 10 of As3MT were respectively associated with higher or lower urinary DMA level by approximately 9 microg L(-1). As3MT was suggested to be one of the major factors affecting the metabolism of dietary organic arsenic in terms of urinary DMA level.

Effects of passive computer use time and non-computer work time on the performance of electronic activity monitoring.

This study aimed to examine the effects of passive and non-computer work time on the estimation of computer use times by electronic activity monitoring. A total of 20 subjects with computers were monitored for 3 h. Average relative error for total computer use time estimation was about 4%, given that non-computer work time was 20% of the 3-h monitored period. No significant impact of passive computer use time was found in this study. Non-computer work time of 40% or less is suggested as criteria for the application of electronic activity monitoring to ensure reliability in the physical work loading assessment. Statement of Relevance: This research studied the criteria of non-computer work time for the appropriate use of electronic activity monitoring to ensure reliability in the assessment of physical work loading. It is suggested that it should be set to 40% or less of the 3-h monitoring period.

Effects of input methods on inter-key press intervals during continuous typing.

Two popular input methods for Chinese typing, Microsoft New Phonetic and Boshiamy, were compared in terms of hand and finger loading, key-pressing speed and typing efficiency. Sixteen subjects typed an English and a Chinese text for 30 min each during two test sessions and all keystrokes and their inter-key press intervals were recorded by electronic activity monitoring software. Typing with Microsoft New Phonetic and with Boshiamy was found to have equal hand loadings, but typing with Microsoft New Phonetic was associated with a higher proportion of keystrokes at the number row. The subjects who used Boshiamy typed significantly more words per min than those who used Microsoft New Phonetic, though both groups had similar English typing speeds. The features of requiring fewer keystrokes to build a character and no need to choose matched words among homophones made Boshiamy a more efficient tool, but the risk of musculoskeletal disorders should be studied further. This study examined two input methods for typing Chinese and showed that typing with Boshiamy had a higher efficiency, including a higher proportion of key presses on the home row, required fewer key presses to build characters and resulted in a faster speed than with Microsoft New Phonetic. However, the potential risk of development of upper limb symptoms warrants further study.

Globally temporal transitions of blood lead levels of preschool children across countries of different categories of Human Development Index.

In the past decades, efforts to eliminate lead from gasoline, paint and drinking water around the world have substantially reduced human blood lead levels. This study was therefore aimed at examining the global temporal trends in the blood lead levels of preschool children by the category of UN Human Development Index (HDI). In total, 103 blood lead records were retrieved from 51 articles searched from PubMed and Google Scholar, with study subjects aged up to 8years old. Collected preschool children blood lead levels were plotted chronologically by HDI category and their reciprocals were used in regression analysis against calendar year to establish their temporal transition trends in the past decades. Results show that the modes of blood lead level of the preschool children were reduced from 4-6µg/dL to 0.8-1.5µg/dL, from 6-15µg/dL to 3-6µg/dL and from 12-16 to 5-6µg/dL for the very high HDI countries, the high HDI countries and the medium/low HDI countries, respectively. The highest correlation coefficient, 0.849, between the reciprocal of blood lead level and the calendar year was found for the very high HDI countries. Based on the regression lines, the predicted preschool children mean blood lead levels in the year of 2030 are 0.74µg/dL, 2.21µg/dL and 2.86µg/dL, respectively, for the very high HDI countries, the high HDI countries and the medium/low HDI countries. Persistent differences in blood lead level prevailed among countries of different HDI category, suggesting the effects of disparities and inequalities, at the state level, on preschool children blood lead levels. Further action is warranted to reduce the already low environmental lead exposure to eliminate the developmental burden of lead on children through (1) identification of individual local factors for lead exposure and (2) averting health disparity and inequalities at the state level.