Astrocytes Optimize the Synaptic Transmission of Information

Chemical synapses transmit information via the release of neurotransmitter-filled vesicles from the presynaptic terminal. Using computational modeling, we predict that the limited availability of neurotransmitter resources in combination with the spontaneous release of vesicles limits the maximum degree of enhancement of synaptic transmission. This gives rise to an optimal tuning that depends on the number of active zones. There is strong experimental evidence that astrocytes that enwrap synapses can modulate the probabilities of vesicle release through bidirectional signaling and hence regulate synaptic transmission. For low-fidelity hippocampal synapses, which typically have only one or two active zones, the predicted optimal values lie close to those determined by experimentally measured astrocytic feedback, suggesting that astrocytes optimize synaptic transmission of information

Ambient air pollution exposure and risk of chronic kidney disease: A systematic review of the literature and meta-analysis

Ambient air pollution has been identified as one of the leading causes of global burden of disease. The relationship between ambient air pollution exposure and risk of chronic kidney disease (CKD) has stimulated increasing scientific interest in the past few years. However, evidence from human epidemiological studies is still limited and inconsistent. We performed an updated systematic review and meta-analysis to clarify the potential association comprehensively. Selected electronic databases were searched for related English language studies until March 1, 2020 with a final follow-up in December 31, 2020. Risk of bias assessment for individual studies were assessed using the OHAT (Office of Health Assessment and Translation) risk-of-bias rating tool. Confidence rating and level-of-evidence conclusions were developed for bodies of evidence for a given ambient air pollutant. Summary effect estimates were calculated using random-effects meta-analyses when three or more studies are identified for the same air pollutant–CKD combination. A total of 13 studies were finally identified in our study. The meta-analytic estimates (ORs) for risk of CKD were 1.15 (95% CI: 1.07, 1.24) for each 10 μg/m3 increase in PM2.5, 1.25 (95% CI: 1.11, 1.40) for each 10 μg/m3 increase in PM10, 1.10 (95% CI: 1.03, 1.17) for each 10 ppb increase in NO2, 1.06 (95% CI: 0.98, 1.15) for each 1 ppb increase in SO2 and 1.04 (95% CI: 1.00, 1.08) for each 0.1 ppm increase in CO, respectively. The level of evidence was appraised as moderate for four of the five tested air pollutant–CKD combinations using an adaptation of the GRADE (Grading of Recommendations Assessment, Development and Evaluation) tool. In conclusion, this study suggests that certain ambient air pollutant exposure was significantly associated with an increased risk of CKD. Given the limitations, the results of this study should be interpreted with caution, and further well-designed epidemiological studies are needed to draw a definite evidence of a causal relationship

The chemical composition of inorganic and carbonaceous materials in PM2.5 in Nanjing, China

PM2.5 samples Were collected at an urban and a suburban site in Nanjing, China in 2001. They were analyzed for inorganic ions, elemental carbon, organic carbon (OC), water-soluble,organic carbon (WSOC), and individual WSOC and nonpolar organic species. Sulfate and organic matter were the two most abundant constituents in these samples. Sulfate accounted for an average of 23\% (urban site) and 30\% (suburban site) of the identified aerosol mass. Organic matter accounted for An average of 37\% (urban) and 28\% (suburban) of the identified aerosol mass. WSOC was a significant portion of OC, accounting for about one-third of OC at the urban site and 45\% of OC at the suburban site. The suburban-urban gradient in the WSOC/OC ratio also reflected that the aerosol OC was more aged at the suburban location. The correlations of WSOC with sulfate and nitrate suggest that. the WSOC fraction was dominated by secondary organics. More than 30 individual WSOC species in the compound classes of organic anions, amino acids, aliphatic amines, and carbohydrates were quantified, accounting for approximately 8\% of the WSOC on a carbon mass basis., In addition, 46 individual nonpolar organic compounds in the compound classes of n-alkanes, hopanes, and polycyclic aromatic hydrocarbons were quantified using an in-injection port thermal desorption technique. These nonpolar organic species accounted for less than 7\% of the OC on a carbon mass basis. The quantification of individual compounds allowed the identification of major aerosol sources through principal component analysis. Coal combustion, vehicular emissions, secondary inorganic and organic aerosols, and road/sea salt were the major contributing sources to the identified PM2.5 aerosol mass. (c) 2005 Elsevier Ltd. All rights reserved

Origin and transformation of ambient volatile organic compounds during a dust-to-haze episode in northwest China

202008 bcrcVersion of RecordPublishe

Volatile organic compounds at a roadside site in Hong Kong : characteristics, chemical reactivity, and health risk assessment

202307 bcwwNot applicableRGCOthersNatural Science Foundation of Shandong Province; Environment and Conservation FundPublished24 month

Evaluation and characterization of volatile air toxics indoors in a heavy polluted city of northwestern China in wintertime

202209 bcfcAccepted ManuscriptOthersNational Key Research and Development Program of China; National Science Foundation of China; Key Project of International Cooperation of the Chinese Academy of SciencesPublishe

Development and application of photocatalytic coating for roadside NOx mitigation in Hong Kong

202307 bcwhNot applicableRGCOthersOve Arup & Partners Hong Kong LimitedEarly release24 month