[Analysis of Photochemical Characteristics and Sensitivity of Atmospheric Ozone in Nanjing in Summer].

Tropospheric ozone (O3) is mainly produced through a series of photochemical reactions of nitrogen oxides (NOx) and volatile organic compounds (VOCs). The reaction process presents complex non-linear relationships. In this work, datasets of atmospheric ozone and volatile organic compounds (VOCs) observed during the summer of 2018 in Nanjing were used. Combining with the framework for 0-D atmospheric model-master chemical mechanism (F0AM-MCM), the characteristics of photochemical reactions for ozone (O3) formation in Nanjing during the O3 episode days and non-episode days were investigated. The results showed that φ(O3) and φ(TVOCs) in the O3 episode days were 47.8×10-9 and 49.0×10-9, respectively, exceeding those in the non-episode days by factors of 1.8 and 1.6. Furthermore, F0AM, the empirical kinetic modeling approach (EKMA), and relative incremental reactivity (RIR) were utilized for the calculation of ozone chemical sensitivity. It was found that O3 formation in Nanjing was attributed to both VOCs and NOx limitation. In addition, the modeled ·OH and HO2 concentrations in the O3 episode days were 1.3 and 1.8 times higher than those in the non-episode days. The higher formation and loss rates of ·OH and HO2 were also found during O3 episode days. These findings reflected that the enhancements of atmospheric oxidation capacity resulted in increased production rates of O3, providing an explanation for the enhancements of O3 concentrations in Nanjing during the O3 episode days. The findings also improved the understanding of the O3 photochemical characteristics over Nanjing in the summer during the O3 episode days.

[Analysis of Formation Processes and Sources of PM2.5 Ammonium During Winter and Summer in Suburban Area of the Yangtze River Delta].

As the main pollutants of secondary inorganic aerosols(SIAs) in fine particulate matter(PM2.5), aerosol ammonium(p-NH4+) plays a significant role in the formation of haze. However, the contribution ratio of each potential source of atmospheric NHx(p-NH4+ and NH3) still remains controversial. In this study, 3 h high-frequency PM2.5 samples were collected in Dongshan, Suzhou during winter and summer in 2015, respectively. Meanwhile, we determined concentrations and δ15N isotope ratios of total nitrogen(TN) and p-NH4+ and quantitatively analyzed formation processes and sources of p-NH4+ based on the Bayesian mixing model(SIAR). SO42-, NO3-, and NH4+ were the main water-soluble ions(WSIs) both in winter and summer, accounting for more than 70% in general. The concentration change trends of PM2.5, TN, and p-NH4+ were consistent, and the concentrations in winter were 2-3 times those in summer. The δ15N-NH4+ value was in direct proportion to the p-NH4+ concentration both in winter and summer. However, δ15N-NH4+ values in winter(-1.7‰±4.3‰) were lower than those in summer(7.8‰±5.9‰). This indicated that the differences in δ15N-NH4+ were caused by different contribution rates of each potential source within each season, whereas it was mainly led by nitrogen isotope fractionation during ammonium-ammonia gas particle distribution in different seasons. The SIAR model calculated that non-agricultural sources were the dominant source of p-NH4+ in Dongshan, with the contribution rate of 59% in winter and 69% in summer, which indicated that NH3 emitted by fossil fuel combustion more easily formed particle aerosol ammonium than that volatilized from agricultural sources.

Effect of electroacupuncture at "Jiaji" (EX-B2) on senescence of nucleus pulposus cells of degenerated lumbar intervertebral disc in rabbits. / 电针"夹脊"å¯¹è °æ¤Žé—´ç›˜é€€å˜å ”é€€å˜æ¤Žé—´ç›˜é«“æ ¸ç»†èƒžè¡°è€çš„å½±å“.

OBJECTIVES: To observe the effect of electroacupuncture (EA) at "Jiaji"(EX-B2) on body mass, motor function, expression of caveolin-1 (Cav-1) in nucleus pulposus cells and annulus fibrosus tissue, telomerase activi-ty, relative telomere length and different cell cycle ratio of nucleus pulposus cells in rabbits with intervertebral disc degeneration(IVDD), so as to investigate its mechanism underlying delaying senescence of the degenerated lumbar intervertebral disc nucleus pulposus cells. METHODS: Twenty-five male New Zealand rabbits with mature bones were divided into control, sham operation, model, EA, and acupuncture groups, with 5 rabbits in each group. The IVDD model was established by inserting kirschner wires to the vertebral bone surface between the lumbar (L)4 and L5 vertebrae, followed by applying continuous axial pressure for 28 d. EA (2 Hz/15 Hz, 1-2 mA) or acupuncture (only insertion of acupuncture needles into bilateral EX-B2, but without electrical stimulation) was applied to bilateral EX-B2 for 20 min, once daily, 6 times a week for 4 weeks. The hindlimb locomotor function (locomotor score) was assessed by using Faden's and colleagues' methods. The general conditions of rabbits in each group were observed, and their body weight changes were measured every week. Nucleus pulposus cells were isolated using enzyme digestion method. After the treatment, the Cav-1 positive cell counts in nucleus pulposus cells and annulus fibrosus tissues were detected by immunohistochemistry, and the telomerase activity of nucleus pulposus cells was detected by PCR-ELISA. The relative telomere length of nucleus pulposus cells was measured by real-time quantitative polymerase chain reaction (real-time qPCR), and the cell cycle of nucleus pulposus was detected by flow cytometry. RESULTS: Compared with the sham operation group, the body mass from 4 to 11 week, locomotor score at 4, 7 and 11 week, telomerase activity, relative telomere length and the proportion of cells in G2/M phase of nucleus pulposus cells were significantly decreased (P<0.01), while Cav-1 positive cell counts of nucleus pulposus and annulus fibrosus tissue, and the proportion of nucleus pulposus cells in the G0/G1 phase considerably increased (P<0.01) in the model group. Relevant to the model group, the EA group rather than the acupuncture group had an increase in the body mass from 8 to 11 week, locomotor score at 11 week, telomerase activity, relative telomere length of nucleus pulposus cells, and the proportion of nucleus pulposus cells in G2/M phase (P<0.01), and a decrease in the Cav-1 positive cell counts of nucleus pulposus and annulus fibrosus tissue and the proportion of cells in G0/G1 phase (P<0.01). No significant differences were found between the model and acupuncture groups in all the indexes mentioned above. CONCLUSIONS: EA at EX-B2 has a bene-ficial effect in improving motor function in rabbits with IVDD, which may be related to its functions in reducing the expression of Cav-1 in nucleus pulposus cells and annulus fibrosus, improving cycle arrest, enhancing the telomerase activity and the relative telomere length of nucleus pulposus cells, delaying the senescence of nucleus pulposus cells of the degenerated lumbar intervertebral discs.

Overlapping Epstein-Barr virus encephalitis and autoimmune glial fibrillary acidic protein astrocytopathy.

We describe three cases of overlapping Epstein-Barr virus (EBV) Encephalitis and Autoimmune Glial Fibrillary Acidic Protein Astrocytopathy (GFAP-A). The three cases all presented with initial symptoms of fever, headache, coma, and posture tremor of the upper limbs, then followed by limb weakness and dysuria. All of the three cases were on ventilators. Case 1 and 2 improved dramatically after intravenous methylprednisoloneand immunoglobulin treatment. However, case 3 presented dyspneic, and died from gastrointestinal hemorrhage. The GFAP-A triggered by EBV intracranial infection could initially masquerade as EBV encephalitis only, and the detection of GFAP antibody is essential for differentiation.

[Emission Factors of Carbonaceous Aerosol and Stable Carbon Isotope for In-use Vehicles].

Vehicle exhaust is an important anthropogenic source of atmospheric carbonaceous aerosols; of which, the emission factors and stable carbon isotope composition are important basic data. In-use motor vehicles of different types were selected to conduct dynamometer tests using different test cycles and under cold/hot start conditions. The exhaust of each test stage was collected to analyze the carbonaceous components and stable carbon isotopes and to discuss the influencing factors. The total carbon emission factors follow the order:heavy-duty diesel vehicles>light-duty diesel vehicles>light-duty gasoline vehicles. Although the emission factors of light-duty natural gas vehicles were very low at the low- and medium-speed stages, they were similar to those of heavy-duty diesel vehicles at the high-speed stage. The emission factors of cold start were higher than those of hot start, and the emission factors of the NEDC test cycle were lower than those of WLTC (which should be related to the driving speed). The emission factors of organic carbon (OC) of gasoline and natural gas vehicles were much higher than those of elemental carbon (EC) in every test stage. The emission factors of OC and EC of diesel vehicles were similar. The OC/EC of all types of vehicles increased with the increase in driving speed. Stable carbon isotopes in EC were higher than those in OC. The stable carbon isotope in different vehicles follow the order:light-duty gasoline vehicles

Wildfire-Derived Nitrogen Aerosols Threaten the Fragile Ecosystem in Himalayas and Tibetan Plateau.

Himalayas and Tibetan Plateau (HTP) is important for global biodiversity and regional sustainable development. While numerous studies have revealed that the ecosystem in this unique and pristine region is changing, their exact causes are still poorly understood. Here, we present a year-round (23 March 2017 to 19 March 2018) ground- and satellite-based atmospheric observation at the Qomolangma monitoring station (QOMS, 4276 m a.s.l.). Based on a comprehensive chemical and stable isotope (15N) analysis of nitrogen compounds and satellite observations, we provide unequivocal evidence that wildfire emissions in South Asia can come across the Himalayas and threaten the HTP's ecosystem. Such wildfire episodes, mostly occurring in spring (March-April), not only substantially enhanced the aerosol nitrogen concentration but also altered its composition (i.e., rendering it more bioavailable). We estimated a nitrogen deposition flux at QOMS of ∼10 kg N ha-1 yr-1, which is approximately twice the lower value of the critical load range reported for the Alpine ecosystem. Such adverse impact is particularly concerning, given the anticipated increase of wildfire activities in the future under climate change.

Increasing Nonfossil Fuel Contributions to Atmospheric Nitrate in Urban China from Observation to Prediction.

China's nitrogen oxide (NOx) emissions have undergone significant changes over the past few decades. However, nonfossil fuel NOx emissions are not yet well constrained in urban environments, resulting in a substantial underestimation of their importance relative to the known fossil fuel NOx emissions. We developed an approach using machine learning that is accurate enough to generate a long time series of the nitrogen isotopic composition (δ15N) of atmospheric nitrate using high-level accuracies of air pollutants and meteorology data. Air temperature was found to be the critical driver of the variation of nitrate δ15N at daily resolution based on this approach, while significant reductions of aerosol and its precursor emissions played a key role in the change of nitrate δ15N on the yearly scale. Predictions from this model found a significant decrease in nitrate δ15N in Chinese megacities (Beijing and Guangzhou as representative cities in the north and south, respectively) since 2013, implying an enhanced contribution of nonfossil fuel NOx emissions to nitrate aerosols (up to 22%-26% in 2021 from 18%-22% in 2013 quantified by an isotope mixing model), as confirmed by the Weather Research and Forecasting model coupled with online chemistry (WRF-Chem) simulation. Meanwhile, the declining contribution in coal combustion (34%-39% in 2013 to 31%-34% in 2021) and increasing contribution of natural gas combustion (11%-14% in 2013 to 14%-17% in 2021) demonstrated the transformation of China's energy structure from coal to natural gas. This approach provides missing records for exploring long-term variability in the nitrogen isotope system and may contribute to the study of the global reactive nitrogen biogeochemical cycle.

[Abnormal Activation of T Cells in HIV-1 Infection After Antiretroviral Therapy].

Objective: To investigate the relationship between abnormal activation of T cell subsets in peripheral whole blood and the recovery of immune function in persons infected with HIV-1, and to examine the relationship between the size of the viral reservoir of HIV-1 DNA and T cell subsets. Methods: HIV-1-infected persons who underwent routine testing between July 2019 and May 2020 were the target population of the study. According to whether, at the time of enrollment, their CD4+ T cells reached 500 cells/µL after antiretroviral therapy (ART), HIV-1-infected persons were divided into two groups, 76 in the deficiency group and 61 in the immune recovery group. In addition, 22 people who were not exposed to HIV-1, and who were tested negative for HIV-1 antibody were selected as the control group. For the three groups of subjects, tests of the T cell subsets were conducted. A total of 77 HIV-1-infected persons, with 44 from the deficiency group and 33 from the recovery group, were examined for HIV-1 DNA reservoir. The deficiency group and the recovery group were followed up 6 months later and the CD4+ T cell test results of 133 blood samples were collected, with 74 from the deficiency group and 59 from the recovery group. Results: The proportions of activated CD4+ and CD8+ T cells of the deficiency group were higher than those of the recovery group and the control group. The proportions of senescent CD4+ and CD8+ T cells in the deficiency group were comparable to those of the recovery group, which were higher than those of the control group, showing significant differences only in senescent CD8+ T cells, and no significant difference in senescent CD4+ T cells. The deficiency group expressed higher levels of effector memory CD4+ T and CD8+ T cells than the control group did, and the recovery group only expressed a higher level of effect memory CD8+ T cells. Both the deficiency group and the recovery group showed lower levels of central memory CD4+ T and CD8+ T cells than the control group did, and the recovery group had an even lower level of central memory CD4+ T cells than the deficiency group did. The recovery group showed a higher expression level of naïve CD4+ T cells, and the deficiency group and the recovery group had lower expression levels of naïve CD8+ T cells than the control group did. There was no correlation between the size of the viral reservoir of HIV-1 DNA and CD4+ T cell count or the T cell subsets. Activated CD4+ T cells, activated CD8+ T cells, and central memory CD4+ T cells were negatively correlated with the follow-up findings for CD4+ T cells, with r at －0.378, －0.334, and －0.322, respectively ( P<0.05). Naïve CD4+ T cells and naïve CD8+ T cells were positively correlated with the follow-up findings for CD4+ T cell subset, with r at 0.350 and 0.267, respectively ( P<0.05). Conclusion: HIV-1 infected persons have varying degrees of abnormal immune activation of T cell subsets. The abnormal activation of some T-cell subsets is partly associated with the subsequent recovery of immune functions and the size of the viral reservoir of HIV-1 DNA was not associated with the T cell subsets.

[Composition Characteristics and Sources of Non-polar Organic Compounds in PM2.5 in the Background Atmosphere of Yangtze River Delta].

In order to explore the composition and source characteristics of non-polar organic compounds (NPOCs) in atmospheric fine particulate matter in the Yangtze River Delta region, 129 PM2.5 samples were collected at the Regional Atmospheric background station in Lin'an from December 2019 to November 2020. Including polycyclic aromatic hydrocarbons (PAHs), n-alkanes, and hopanes, the main sources of organic aerosols were investigated using molecular tracers, eigen ratios, and orthogonal matrix factorization models. The results showed that the average annual mass concentration of PM2.5 in Lin'an was approximately (32.36±20.44) µg·m-3, and the average annual mass concentration of NPOCs was approximately (59.05±40.39) ng·m-3, showing the seasonal characteristics of being high in winter and low in summer. n-alkanes mainly came from fossil fuels and biomass (grass, wood, etc.) burning, followed by cuticle wax emission from higher plants. PAHs mainly came from the mixed contribution of non-fossil sources such as coal burning motor vehicle emissions and biomass combustion. Hopanes were mainly derived from motor vehicle emissions, which were also affected by coal burning in winter. Backward trajectory cluster analysis and potential source analysis showed that Lin'an was mainly affected by external air mass transport. Combined with the orthogonal matrix-factor decomposition model, NPOCs observed during the sampling period were analyzed, and non-fossil sources such as coal burning sources, transportation emission sources, and biomass combustion were obtained. In winter, transportation sources were the main source, accounting for 59%. In spring and summer, coal burning was the main source, accounting for 58% and 57%, respectively. In autumn, biomass combustion and other non-fossil sources dominated, accounting for 64%.