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China has been experiencing a sharp increase in outdoor ozone concentration. The deposition velocity of ozone onto human surfaces strongly affects the indoor ozone concentration, and the production of oxidation products. In this study, we measured the deposition velocity of ozone onto human surfaces in six Chinese residential rooms, each housing 1–3 occupants. In addition, we estimated the corresponding emission rate of oxidation products. The measured mean value of the deposition velocity is 14.8 (±10.1) m/h, which is close to those reported in earlier studies in western countries. We also find that the ozone deposition velocity onto human surfaces is positively correlated to the weighted duration from the last laundry and bath/facial-cleansing, and it is negatively correlated to the relative humidity of the indoor air. The estimated emission rates of 6-MHO, 4-OPA, acetone, geranyl acetone, 1,4-butanedial decanal, and all gas-phase products are 7.7 × 1016, 6.7 × 1016, 9.4 × 1016, 9.7 × 1015, 1.3 × 1016, 3.4 × 1016, and 4.8 × 1017 molecule per person h−1, respectively, with an indoor ozone concentration of 5 ppb at steady state. The measured deposition velocity of ozone onto human surfaces of Chinese residents, and the emission rates of the corresponding oxidation products may be applied for the estimation of human exposure to ozone and its oxidation products in China.

Background Sleep disorder-associated cognitive impairments are often accompanied by impaired synaptic plasticity. In the pathological process of sleep deprivation, microglia, as an important innate immune cell in central nervous system, are involved and mediate the synaptic pruning, in which the CX3C-chemokine receptor 1 receptor (CX3CR1) plays an indispensable role. In this study, the potential role of CX3CR1 in modulating the cognition decline during sleep deprivation was evaluated in terms of microglial neuroinflammation and synaptic pruning. Methods Middle-aged wild type C57BL/6 mice (WT) (13 months) and age-matched CX3CR1 -/- mice were either subjected to sleep deprivation (SD) or allowed normal sleep (S) for 8 h to mimic the pathophysiological changes of middle-aged people after staying up all night in real life. The hippocampus-dependent cognition was assessed by fear conditioning test. Mice brains were extracted for neuroinflammation and synaptic pruning studies. Data were analyzed by Student’s t-test and one-way analysis of variance (one-way ANOVA). Results The CX3CR1 deficiency mice differed from WT mice in many measures. CX3CR1 deficiency prevented SD-induced cognitive impairments, in which the levels of brain-derived neurotrophic factor (BDNF) and phosphorylated cAMP-responsive element binding protein (p-CREB) were markedly increased in the hippocampus. Compared with the CX3CR1 -/- -S group, the CX3CR1 -/- -SD mice reported a markedly decreased microglial density in the dentate gyrus, notably-decreased levels of cellular oncogene fos (c-fos), and pro-inflammatory cytokines and increased levels of anti-inflammatory cytokines in the hippocampus, and a significant increase in the density of spines of the dentate gyrus area. Furthermore, the CX3CR1 -/- -SD group also showed a decreasing expression of microglial phagocytosis-related factors. Conclusion These findings suggest that CX3CR1 deficiency leads to different cerebral behaviors and responses to sleep deprivation. CX3CR1 deletion can alleviate the sleep deprivation-induced cognitive impairment. The inflammation-attenuating activity and the related modification of synaptic pruning are possible mechanism candidates, which indicate CX3CR1 as a candidate therapeutic target for the prevention of the sleep loss-induced cognitive impairments.

Cu and As were separated and recovered from copper electrolyte by multiple stage electrowinning, reduction with SO 2 and evaporative crystallization. Experimental results showed that when the current density was 200 A/m 2 , the electrolyte temperature was 55 °C, the electrolyte circulation rate was about 10 mL/min and the final Cu concentration was higher than 25.88 g/L, the pure copper cathode was recovered. By adjusting the current density to 100 A/m 2 and the electrolyte temperature to 65 °C, the removal rate of As was 18.25% when the Cu concentration decreased from 24.69 g/L to 0.42 g/L. After As(V) in Cu-depleted electrolyte was fully reduced to As(III) by SO 2 , the resultant solution was subjected to evaporative crystallization, then As 2 O 3 was produced, and the recovery rate of As was 59.76%. The cathodic polarization curves demonstrated that both Cu 2+ concentration and As(V) affect the limiting current of Cu 2+ deposition.

Purpose: To describe the prevalence and to identify associated risk factors for pterygium in a Tibetan population at high altitude in Zeku County, China. Methods: A prospective population-based survey was conducted from October to December 2006. A stratified, clustered, randomized sampling procedure was used to select 2632 Tibetan people aged 40 years and older. Pterygium was diagnosed and graded clinically as grade 1 (transparent), 2 (intermediate) and 3 (opaque). Risks factors associated with pterygium were evaluated with logistic regression models. Results: From a total of 2632 eligible subjects, 2229 (84.69%) were examined. There were 323 people with pterygium, equivalent to an overall prevalence of 14.49% (95% confidence interval [CI] 13.03–15.95). Pterygium was independently associated with increasing age for persons aged 70–79 years, compared with those aged 40–49 years (odds ratio [OR] 2.0; 95% CI 1.4–2.8), female gender (OR 1.6; 95% CI 1.2–2.0), dry eye symptoms (OR 1.3; 95% CI 1.0–1.7), seldom use of sunglasses/crystal spectacles (OR 4.6; 95% CI 1.9–11.3) or hats (OR 3.6: 95% CI 2.4–5.4), lower education level (

To determine the prevalence of dry eye syndrome, analyze the relationship between dry eye symptoms and signs, and identify associated risk factors for dry eye syndrome in an elderly Tibetan population at high altitude.A population-based survey was conducted from October 2006 to December 2006. A stratified, clustered, random sampling procedure was used to select 2632 native Tibetan peopleor=40 years of age. Symptoms of dry eye were assessed by using a 6-item validated questionnaire. Dry eye syndrome was diagnosed in those subjects having 1 or more symptoms often or all the time. Positive signs included a tear film breakup time ofor=10 seconds in 1 or both eyes, a Schirmer test score ofor=5 mm, or a fluorescein score ofor=1. Correlations between symptoms and signs were analyzed.Of a total of 2632 eligible subjects, 2229 (84.69%) were examined. The data of 1840 participants were analyzed. Of 1840 participants, 52.4% (95% confidence interval: 50.2-54.7) were symptomatic. The tear film breakup time ofor=10 seconds was seen in 35.3% (95% confidence interval: 33.1-37.5), a Schirmer test score ofor= 5 mm was seen in 24.7% (95% confidence interval: 22.8-26.7), and a fluorescein score ofor=1 was seen in 5.8% (95% confidence interval: 4.7-6.9). The correlations between dry eye symptoms and signs were statistically significant. Independent risk factors for dry eye syndrome were positive dry eye signs, increased age, low education level and socioeconomic status, and higher altitude.This study shows a high prevalence rate of dry eye syndrome in elderly Tibetans, representing an important health problem.

To describe the prevalence and to identify associated risk factors for pterygium in a Tibetan population at high altitude in Zeku County, China.A prospective population-based survey was conducted from October to December 2006. A stratified, clustered, randomized sampling procedure was used to select 2632 Tibetan people aged 40 years and older. Pterygium was diagnosed and graded clinically as grade 1 (transparent), 2 (intermediate) and 3 (opaque). Risks factors associated with pterygium were evaluated with logistic regression models.From a total of 2632 eligible subjects, 2229 (84.69%) were examined. There were 323 people with pterygium, equivalent to an overall prevalence of 14.49% (95% confidence interval [CI] 13.03-15.95). Pterygium was independently associated with increasing age for persons aged 70-79 years, compared with those aged 40-49 years (odds ratio [OR] 2.0; 95% CI 1.4-2.8), female gender (OR 1.6; 95% CI 1.2-2.0), dry eye symptoms (OR 1.3; 95% CI 1.0-1.7), seldom use of sunglasses/crystal spectacles (OR 4.6; 95% CI 1.9-11.3) or hats (OR 3.6: 95% CI 2.4-5.4), lower education level (3 years) (OR 1.6; 95% CI 1.1-2.4) and low socioeconomic status (OR 1.9; 95% CI 1.5-2.4).The prevalence of pterygium in a Tibetan population at high altitude is significantly high, particularly in certain at-risk groups. The primary causative factors are related to ocular sun exposure, which are easily preventable. Public health schemes to address this serious health issue are urgently needed.