Cruise observation of the marine atmosphere and ship emissions in South China Sea: Aerosol composition, sources, and the aging process.

Marine atmospheric aerosols impact the global climate and biogeochemical cycles. However, how the composition, sources, and aging of these aerosols affect the above processes has not been thoroughly studied. Here, we conducted ship-based measurements in the northern South China Sea to investigate the chemical composition and aging of aerosols from various sources during the summer of 2019. Separate measurements were conducted at the bow (marine environment) and stern (cooking, smoking, and engine exhaust) of the ship. Source apportionment of organic aerosols (OAs) was conducted using positive matrix factorization (PMF) and trajectory models. The results showed that ship exhaust and coastal submicron particles were composed of comparable sulfate and organic fractions (both approximately 43%), distinct from the sulfate-dominated particles in the marine atmosphere (52-77%). PMF using the multilinear engine-2 solver identified five factors for the stern sampling period: hydrocarbon-like OA (HOA-I, 9%), slightly oxidized HOA (HOA-II, 25%), cooking OA (COA, 13%), cigarette smoke OA (CSOA, 4%), and low-volatility oxygenated OA (LV-OOA, 49%). The primary OAs (HOA-I/II + COA + CSOA), derived mostly from direct ship-related emissions, contributed to approximately half of the OAs, whereas the contribution from the highly aged marine atmosphere was only 20%. Notably, certain living-related emissions (i.e., COA and CSOA), which were often neglected in previous studies, might represent a considerable contribution to OA emissions from the ship. Four factors were identified for the bow sampling periods: HOA (13%), biomass burning OA (BBOA, 9%), semi-volatile OOA (7%), and LV-OOA (71%). The BBOAs from the Indo-China and Malay peninsulas were aged, converted to secondary organic aerosols (SOAs) during transport, and influenced by the combined photo-oxidation and liquid-phase reactions, indicating a substantial impact of BB on SOA formation. Our study highlights the influence of ship and inland emissions and their aging during transport on marine atmospheric aerosols.

[Different stimulation methods on auricular points for primary dysmenorrhea: a randomized controlled trial].

OBJECTIVE: To prove the therapeutic effect of auricular intradermal needling and auricular point sticking on primary dysmenorrhea (PD), and to explore its mechanism. METHODS: A total of 90 patients with PD were randomized into an auricular intradermal needling group, an auricular point sticking group and a placebo group, 30 cases in each one. Neishengzhiqi (TF2), Neifenmi (CO18), Shenmen (TF4), Shen (CO10), Jiaogan (AH6a), Gan (CO12) and Pizhixia (AT4) were selected in the 3 groups, intradermal needling and cowherb seed sticking were applied respectively in the auricular intradermal needling group and the auricular point sticking group, adhesive tape without needle was stuck in the placebo group. Pressing and kneading for 3 to 4 times were required each day, 3 to 4 min each time, and the intervention was started 5 d before menstruation, once every other day, 4 times each menstrual cycle were as one course, and totally 3 courses were required in the 3 groups. The follow-up was adopted at the next menstruation after treatment. The Cox menstrual symptom scale (CMSS) score, the visual analogue scale (VAS) score and the self-rating anxiety scale (SAS) score before treatment, 1,2,3 courses into treatment and at follow-up were compared, the serum levels of PGF2αand PGE2 before and after treatment were detected, and the clinical therapeutic effect was evaluated in the 3 groups. RESULTS: Compared before treatment, the scores of CMSS, VAS and SAS were decreased at each time point of treatment in the auricular intradermal needling group, 2, 3 courses into treatment and at follow-up in the auricular point sticking group and 3 courses into treatment in the placebo group (P<0.001, P<0.05). Compared with the auricular point sticking group, the CMSS scores at each time point of treatment and the VAS scores of 1, 2 courses and at follow-up were decreased in the auricular intradermal needling group (P<0.05). Compared with the placebo group, the CMSS scores were decreased at each time point of treatment in the auricular intradermal needling group and 3 courses into treatment and at follow-up in the auricular point sticking group (P<0.001, P<0.05); the VAS scores were decreased at each time point of treatment in the auricular intradermal needling group and the auricular point sticking group (P<0.001, P<0.05). After treatment, the serum levels of PGF2α were decreased (P<0.05) and the serum levels of PGE2 were increased (P<0.05) in the auricular intradermal needling group and the auricular point sticking group, and the serum levels of PGF2α were lower than the placebo group (P<0.05), the serum levels of PGE2 were higher than the placebo group (P<0.05) in the two groups. Compared with the auricular point sticking group, the serum level of PGF2 was decreased (P<0.05), the serum level of PGE2α was increased in the auricular intradermal needling group (P<0.05). The total effective rates were 93.3% (28/30) in the auricular intradermal needling group and 80.0% (24/30) in the auricular point sticking group, which were both superior to 63.3% (19/30) in the placebo group (P<0.05). CONCLUSION: Auricular intradermal needling and auricular point sticking can both improve the clinical symptom of primary dysmenorrhea, relieve the pain and anxiety, their mechanism may be related to regulating the serum levels of PGF2α and PGE2. The therapeutic effect of auricular intradermal needling is superior to auricular point sticking, and the placebo effect can be preliminarily excluded.

Air Quality During COVID-19 Lockdown in the Yangtze River Delta and the Pearl River Delta: Two Different Responsive Mechanisms to Emission Reductions in China.

Despite the large reduction in anthropogenic activities due to the outbreak of COVID-19, air quality in China has witnessed little improvement and featured great regional disparities. Here, by combining observational data and simulations, this work aims to understand the diverse air quality response in two city clusters, Yangtze River Delta region (YRD) and Pearl River Delta region (PRD), China. Though there was a noticeable drop in primary pollutants in both the regions, differently, the maximum daily 8 h average ozone (O3) soared by 20.6-76.8% in YRD but decreased by 15.5-28.1% in PRD. In YRD, nitrogen oxide (NOx) reductions enhanced O3 accumulation and hence increased secondary aerosol formation. Such an increment in secondary organic and inorganic aerosols under stationary weather reached up to 36.4 and 10.2%, respectively, which was further intensified by regional transport. PRD was quite the opposite. The emission reductions benefited PRD air quality, while regional transport corresponded to an increase of 17.3 and 9.3% in secondary organic and inorganic aerosols, respectively. Apart from meteorology, the discrepancy in O3-VOCs-NOx relationships determined the different O3 responses, indicating that future emission control shall be regionally specific, instead of one-size-fits-all cut. Overall, the importance of regionally coordinated and balanced control strategy for multiple pollutants is highly emphasized.

[Needle-embedding treatment for hemifacial spasm: research progress].

The articles regarding needle-embedding treatment for hemifacial spasm published before September 30, 2019 were searched from SinoMed, Wanfang, CNKI, VIP and PubMed database, and were analyzed and summarized from treatment methods, acupoint selection, stage differentiation and action mechanism. As a result, 45 Chinese articles were obtained. The needle-embedding treatment was divided into intradermal needling and acupoint thread-embedding; the top five acupoints were Sibai (ST 2), Taiyang (EX-HN 5), Dicang (ST 4), Jiache (ST 6) and spasm trigger points. The basic research of needle-embedding treatment for hemifacial spasm is weak, and the literature regarding stage differentiation is insufficient, which are in need of further study.

Trend analysis of surface ozone at suburban Guangzhou, China.

The long-term variations of ozone are the combined results of climate change and air quality management. As Guangzhou is under the influence of both subtropical monsoon climate and rapid economic development, the ozone trend in recent years is uncertain. This paper presents the trend analysis of maximum daily average 8 h (MDA8) ozone and daily meteorological observations in Guangzhou from 2008 to 2018, using the Kolmogorov-Zurbenko (KZ) filter method. The observations were conducted at two sites in suburban Guangzhou, thus the datasets were processed in two periods. The first period (P1) is from 2008 to 2013, and the second period (P2) is from 2014 to 2018. Results show that the KZ filter method separates the short-term, seasonal, and long-term components efficiently, leaving a covariance term of 7.3% (5.4%) for P1 (P2). Through linear regression of long-term components, the trends were inferred as -0.06 ±â€¯0.04 ppb year-1 (R2 = 0.00, p < 0.05) for P1, and 0.51 ±â€¯0.08 ppb year-1 (R2 = 0.11, p < 0.05) for P2. It is found that the solar radiation has the strongest impact on ozone. With inclusion of temperature, relative humidity, and wind speed, these four meteorological factors held 71% (76%) variability in baseline ozone (sum of seasonal and long-term ozone) for P1 (P2). After applying the KZ filter method, the results reveal that the variance contribution of emission to long-term ozone variation is larger than that of meteorology in P1, while smaller in P2. Furthermore, 59% of the emission-induced ozone change in P2 could be explained by nitrogen dioxide variation, and their inverse correlation suggests that Guangzhou is mainly under volatile organic compounds-limited regime, despite continuous nitrogen oxides reduction.

Aggravating O3 pollution due to NOx emission control in eastern China.

During the past five years, China has witnessed a rapid drop of nitrogen oxides (NOx) owing to the wildly-applied rigorous emission control strategies across the country. However, ozone (O3) pollution was found to steadily deteriorate in most part of eastern China, especially in developed regions such as Jing-Jin-Ji (JJJ), Yangtze River Delta region (YRD) and Pearl River Delta region (PRD). To shed more light on current O3 pollution and its responses to precursor emissions, we integrate satellite retrievals, ground-based measurements together with regional numerical simulation in this study. It is indicated by multiple sets of observational data that NOx in eastern China has declined more than 25% from 2012 to 2016. Based on chemical transport modeling, we find that O3 formation in eastern China has changed from volatile organic compounds (VOCs) sensitive regime to the mixed sensitive regime due to NOx reductions, substantially contributing to the recent increasing trend in urban O3. In addition, such transitions tend to bring about an ~1-1.5 h earlier peak of net O3 formation rate. We further studied the O3 precursors relationships by conducting tens of sensitivity simulations to explore potential ways for effective O3 mitigation. It is suggested that the past control measures that only focused on NOx may not work or even aggravate O3 pollution in the city clusters. In practice, O3 pollution in the three regions is expected to be effectively mitigated only when the reduction ratio of VOCs/NOx is greater than 2:1, indicating VOCs-targeted control is a more practical and feasible way.

[Analysis of Peroxyacetyl Nitrate and Ozone During a Typical Photochemical Pollution Process at the Panyu Atmospheric Composition Station].

The typical photochemical pollution process in Guangzhou was analyzed from 2010 to 2016 by observing photochemical pollutants (ozone (O3), peroxyacetyl nitrate (PAN), volatile organic compounds (VOCs), nitrogen dioxide (NO2), and nitric oxide (NO)) and meteorological factors at the Guangzhou Panyu Atmospheric Composition Station (GPACS). The results showed that during this photochemical pollution process, the average O3 and PAN concentrations were relatively high:O3,max 1 h concentration was 140.6×10-9 and PANmax 1 h concentration was 4.7×10-9. The average concentration of NO was low, which had little effect on O3 titration and PAN elimination. The high NO2 concentration, strong radiation, and low wind speed all led to the formulation and accumulation of O3 and PAN. The linear relationship between O3 and PAN (R2=0.55) was affected by the fact that their precursor VOCs were not similar. Ethene, propane, isoprene, and toluene had a large influence in PAN formation, while isoprene, 1,3,5-trimethylbenzene, propene, m,p-xylene, and toluene had a large influence on O3 formation potential. When evaluating PA concentration, we found that its daily average concentration ranged from 0.11×10-12 to 0.16×10-12, which were higher than many places around the world, indicating that this photochemical process was relatively intensive.

[A Method of Aerosol Particle Number Size Distribution Inversed by PM2.5 Mass Concentration in PRD].

The aerosol particle number size distribution(PNSD) is of great importance in calculating atmospheric radiation and optics. It can effectively supplement the inadequate observation of PNSD using the widely known aerosol mass concentration (PM2.5) measurement to invert PNSD. It would be valuable for research that needs PNSD data, like atmospheric visibility calculation. This paper created a PNSD inversed method based on the statistics and parameterization of the dry aerosol PM2.5 and PNSD dataset from the Guangzhou urban site's simultaneous measurements from November 2014 to January 2015. The inversed results appeared good in the accumulation mode, whereas more differences showed with higher PM2.5 loading. The applicability and stability of this method makes it preferable. It would provide advanced technical support for the visibility calculation and application in PRD.

[Effect of VOCs on O3 and SOA Formation Potential During the Combined Pollution Process in Guangzhou Panyu Atmospheric Composition Station].

An analysis was made by using historical observational data of Guangzhou Panyu Atmospheric Composition Station(GPACS). The results showed that typical haze processes accompanied with high ozone episodes happened during the period from September 2rd, 2011 to September 5th, 2011(P1) and the period from June 12th, 2012 to June 15th, 2012(P2) respectively. During the two combined pollution processes (P1 and P2), daily visibility ranged from 5.78 km to 6.91 km and from 5.60 km to 9.25 km, and the maximum 8 h O3reached 92.14×10-9 and 91.29×10-9 respectively. Among the 55 detected volatile organic compounds(VOCs), alkenes and aromatics had the highest reactivity with the 41%, 39% proportions of equivalent propylene concentration and the proportions of 28%, 54% in the aspect of ozone formation potential during P1. Alkenes and aromatics contributed 35% and 46% of equivalent propylene concentration, as well as 22% and 61% to ozone formation potential during P2. In terms of SOA formation potential by FAC estimation, alkanes, alkenes and aromatics accounted for 13.2%, 21.4%, 65.4% during P1 and 4.6%, 13.8%, 81.6% during P2 respectively. Toluene, isoprene, ethylbenzene and m,p-Xylene had large contributions to the ozone and SOA formation. Factors including pollutants transported from the downtown area, continuous gentle wind, high temperature, low humidity and strong radiation gave rise to the occurrence of high ozone episodes in these two haze processes.

An analysis of aerosol liquid water content and related impact factors in Pearl River Delta.

Aerosol liquid water content (ALWC) has an important effect on atmospheric visibility as well as heterogeneous chemical reactions. In this paper, we used the data size-resolved particle hygroscopic growth factor, and particle number size distribution (PNSD) obtained from H-TDMA and SMPS to compute ALWC at the Guangzhou Panyu site from the winter of 2014 and the spring of 2015. The corresponding results were relatively consistent with the trend for ALWCISO calculated from the ISORROPIA II thermodynamic equilibrium model based on the measurement of aerosol water-soluble ionic compositions obtained from MARGA, with a linear fit yielding an R2 value of 0.76. The fact that ALWCHTDMA was somewhat higher than ALWCISO at low RH values was at least partially attributable to the fact that effects resulting from organic matter hygroscopicity were not taken into account when computing ALWCISO. In sensitivity testing, ambient relative humidity, PNSD and particle hygroscopicity were all found to affect ALWC, in that order. Particles of different modes made different contributions to ALWC with the contributions of nuclear, Aitken, accumulation and coarse modes assessed at <1%, 3%, 85% and 12%, respectively, indicating that the contribution of accumulation mode particles to ALWC dominated among all the aerosol particle modes. During clean processes, decreases in relative humidity and PM2.5 both resulted in a decrease in ALWC. During the pollution processes, calm winds caused local particle accumulation, with ALWC increasing as RH increased. Intraday trends in ALWC and relative humidity were consistent, with minimum mean values observed in the afternoon due to low ambient relative humidity inhibiting an increase in ALWC. However, diurnal variation of aerosol hygroscopicity and ALWC tended to be somewhat anti-correlated, indicating that diurnal changes in aerosol hygroscopicity are not a primary factor resulting in ambient AWLC changes.

Study on aerosol optical properties and radiative effect in cloudy weather in the Guangzhou region.

Currently, Guangzhou region was facing the problem of severe air pollution. Large amount of aerosols in the polluted air dramatically attenuated solar radiation. This study investigated the vertical optical properties of aerosols and inverted the height of boundary layer in the Guangzhou region using the lidar. Simultaneously, evaluated the impact of different types of clouds on aerosol radiation effects using the SBDART. The results showed that the height of the boundary layer and the surface visibility changed consistently, the average height of the boundary layer on the hazy days was only 61% of that on clear days. At the height of 2km or lower, the aerosol extinction coefficient profile distribution decreased linearly along with height on clear days, but the haze days saw an exponential decrease. When there was haze, the changing of heating rate of atmosphere caused by the aerosol decreased from 3.72K/d to 0.9K/d below the height of 2km, and the attenuation of net radiation flux at the ground surface was 97.7W/m(2), and the attenuation amplitude was 11.4%; when there were high clouds, the attenuation was 125.2W/m(2) and the attenuation amplitude was 14.6%; where there were medium cloud, the attenuation was 286.4W/m(2) and the attenuation amplitude was 33.4%. Aerosol affected mainly shortwave radiation, and affected long wave radiation very slightly.

[Characteristics Analysis of Sulfur Dioxide in Pearl River Delta from 2006 to 2010].

Based on the in-situ SO2 observation dataset from 2006 to 2010 in Pearl River Delta(PRD) , the temporal characteristics of SO2 are analyzed. The results show that the annual average volume fraction of surface SO2 in 2010 declines to a level below average values in recent years, with reducing the frequency of high concentration episodes occurring. The seasonal, monthly and diurnal characteristics of surface SO2 are influenced by particular weather conditions in the PRD. The Probability Distribution Function(PDF) of surface SO2 volume fraction are complicated. The PDF is different every month maybe caused by the variation of the seasonal factors.

Simultaneous determination of atropine, scopolamine, and anisodamine from Hyoscyamus niger L. in rat plasma by high-performance liquid chromatography with tandem mass spectrometry and its application to a pharmacokinetics study.

In order to investigate the pharmacokinetics of tropane alkaloids in Hyoscyamus niger L., a sensitive and specific high-performance liquid chromatography with tandem mass spectrometry method for the simultaneous determination of atropine, scopolamine, and anisodamine in rat plasma is developed and fully validated, using homatropine as an internal standard. The separation of the four compounds was carried out on a BDS Hypersil C18 column using a mobile phase consisting of acetonitrile and water (containing 10 mmol ammonium acetate). Calibration curves were linear from 0.2 to 40 ng/mL for atropine, scopolamine, and from 0.08 to 20 ng/mL for anisodamine. The precision of three analytes was <5.89% and the accuracy was between -1.04 to 2.94%. This method is successfully applied to rat pharmacokinetics analysis of the three tropane alkaloids after oral administration of H. niger extract. The maximum concentration of these three tropane alkaloids was reached within 15 min, and the maximum concentrations were 31.36 ± 7.35 ng/mL for atropine, 49.94 ± 2.67 ng/mL for scopolamine, and 2.83 ± 1.49 ng/mL for anisodamine. The pharmacokinetic parameters revealed areas under the curve of 22.76 ± 5.80, 16.80 ± 3.08, and 4.31 ± 1.21 ng/h mL and mean residence times of 2.08 ± 0.55, 1.19 ± 0.45, and 3.28 ± 0.78 h for atropine, scopolamine, and anisodamine, respectively.

In vitro and in vivo release characteristics of Tacrolimus (FK506) from an episcleral drug-delivery implant.

PURPOSE: To investigate the in vitro and in vivo release characteristics of Tacrolimus (FK506) from an episcleral drug-delivery implant. METHODS: For in vitro experiments, Tacrolimus-loaded implants (0.5 mL; at concentrations of 0.25, 0.5, and 1.0 mg/mL) were immersed in a balanced salt solution. Samples of the surrounding liquid were aspirated at different times over a 96-h period. For in vivo experiments, the experimental group received an implant loaded with Tacrolimus (0.5 mg/mL; 0.5 mL); the control group was given a subconjunctival injection of 0.5 mL Tacrolimus (0.5 mg/mL). On postoperative days 3, 7, 14, 28, and 56, 3 animals were sacrificed, and their eyes were enucleated. Tacrolimus concentrations were determined by liquid chromatographic-tandem mass spectrometry. Ocular toxicity was evaluated by slit-lamp photography, fundus photography, intraocular pressure (IOP), and histology. RESULTS: The implants released Tacrolimus in a biphasic pattern for 96 h in the in vitro study. The release kinetics were not dependent on the drug concentrations. The in vivo study showed statistically significant differences between the 2 treatment groups. Tacrolimus levels were particularly high in the conjunctiva, iris, ciliary body, cornea, sclera, choroid, and retina in the experimental group, while concentrations were low and only lasted for 1 week in the controls. Slit-lamp photography, fundus photography, IOP, and histology showed no evidence of toxic effects. CONCLUSIONS: The episcleral drug-delivery implant mechanically released Tacrolimus through the apertures of capsules and, consequently, may be a promising drug vehicle for the treatment of immune-mediated ocular disorders.

Determination of tacrine-6-ferulic acid in rat plasma by LC-MS/MS and its application to pharmacokinetics study.

Tacrine, as a drug for treating Alzheimer's disease (AD), has low efficacy owing to its single function and serious side effects. However, tacrine-6-ferulic acid (T6FA), the dimer which added ferulic acid to tacrine, has been found to be a promising multifunctional drug candidate for AD and much more potent and selective on acetylcholinesterase (AChE) than tacrine. The aim of the present work was to develop and validate an LC-MS/MS method with electrospray ionization for the quantification of T6FA in rat plasma using tacrine-3-ferulic acid (T3FA) as internal standard and to examine its application for pharmacokinetic study in rats. Following a single liquid-liquid extraction with ethyl acetate, chromatographic separation was achieved at 25 °C on a BDS Hypersil C18 column with a mobile phase composed of 1% formic acid and methonal (30:70, v/v) at a flow rate of 0.2 mL/min. Quantification was achieved by monitoring the selected ions at m/z 474.2 → 298.1 for T6FA and m/z 432.2 → 199.0 for T3FA. The method was validated to be rapid, specific, accurate and precise over the concentration range of 0.5-1000.0 ng/mL in rat samples. Furthermore, it was successfully applied for the pharmacokinetic measurement of T6FA with an oral administration at 40 mg/kg to rats.

Compositions and sources of organic acids in fine particles (PM2.5) over the Pearl River Delta region, South China.

Organic acids as important constituents of organic aerosols not only influence the aerosols' hygroscopic property, but also enhance the formation of new particles and secondary organic aerosols. This study reported organic acids including C14-C32 fatty acids, C4-C9 dicarboxylic acids and aromatic acids in PM2.5 collected during winter 2009 at six typical urban, suburban and rural sites in the Pearl River Delta region. Averaged concentrations of C14-C32 fatty acids, aromatic acids and C4-C9 dicarboxylic acids were 157, 72.5 and 50.7 ng/m3, respectively. They totally accounted for 1.7% of measured organic carbon. C20-C32 fatty acids mainly deriving from higher plant wax showed the highest concentration at the upwind rural site with more vegetation around, while C14-C18 fatty acids were more abundant at urban and suburban sites, and dicarboxylic acids and aromatic acids except 1,4-phthalic acid peaked at the downwind rural site. Succinic and azelaic acid were the most abundant among C4-C9 dicarboxylic acids, and 1,2-phthalic and 1,4-phthalic acid were dominant aromatic acids. Dicarboxylic acids and aromatic acids exhibited significant mutual correlations except for 1,4-phthalic acid, which was probably primarily emitted from combustion of solid wastes containing polyethylene terephthalate plastics. Spatial patterns and correlations with typical source tracers suggested that C14-C32 fatty acids were mainly primary while dicarboxylic and aromatic acids were largely secondary. Principal component analysis resolved six sources including biomass burning, natural higher plant wax, two mixed anthropogenic and two secondary sources; further multiple linear regression revealed their contributions to individual organic acids. It turned out that more than 70% of C14-C18 fatty acids were attributed to anthropogenic sources, about 50%-85% of the C20-C32 fatty acids were attributed to natural sources, 80%-95% of dicarboxylic acids and 1,2-phthalic acid were secondary in contrast with that 81% of 1,4-phthalic acid was primary.

Combination of ¹H NMR- and GC-MS-based metabonomics to study on the toxicity of Coptidis Rhizome in rats.

BACKGROUND: Coptidis Rhizome (CR), widely applied to treat with heat and toxicity, is one of the most commonly used traditional Chinese medicine (TCM), however, an extensive dosage can induce toxicity. Diarrhea is one of the most frequent side effects of CR treatment. METHODOLOGY/PRINCIPAL FINDINGS: In this study, metabonomics was combined with the multivariate statistical analysis to discover the endogenous metabolites which related to the diarrheal induced by CR. The male Sprague-Dawley rats were dosed with 4.95 g CR/kg weight. Urine samples were collected at day -1 (before treatment), and days 14 and 21 for NMR analysis. Serum and tissues were collected at day 14 for GC-MS analysis and histopathological examination, respectively. The urine and serum metabolic profiles provided clearer distinction between CR-treated group and control group, which was confirmed by body weight change and diarrhea. Through multivariate statistical analysis, 12 marker metabolites from ¹H NMR and 8 ones from GC-MS have been found. Among those metabolites, hippurate, acetate, alanine, glycine and glutamate are likely to break the balance of gut microbiota, whereas, lactate and 2-ketoisovalerate showed association with energy metabolism. Meanwhile, we observed that the CR-induced toxicity will recover when the treatment was stopped. CONCLUSIONS/SIGNIFICANCE: These results suggest that the main reason for the CR-associated diarrhea might be disturbance in the normal gut microbiota. This metabonomics approach may provide an effective way to study the alteration of gut microbiota, which is expected to find broader application in other drug-induced gastrointestinal reaction assessment.

Simultaneous determination of borneol and its metabolite in rat plasma by GC-MS and its application to pharmacokinetic study.

A gas chromatography mass spectrometry (GC-MS) method has been developed and fully validated for the simultaneous determination of natural borneol (NB) and its metabolite, camphor, in rat plasma. Following a single liquid-liquid extraction, the analytes were separated using an HP-5MS capillary column (0.25 mm×30 m×0.25 µm) and analyzed by MS in the selected ion monitoring mode. Selected ion monitor (m/z) of borneol, camphor and internal standard was 95, 95 and 128, respectively. Linearity, accuracy, precision and extraction recovery of the analytes were all satisfactory. The method was successfully applied to pharmacokinetic studies of NB after oral administration to Wistar rats.

Characterization of secondary aerosol and its extinction effects on visibility over the Pearl River Delta Region, China.

Aerosol samples collected from July 2007 to March 2008 were used to obtain major aerosol constituents in an urban location in the Pearl River Delta Region (PRD), China. The minimum organic carbon (OC)/elemental carbon (EC) ratio was used to calculate the primary and secondary organic carbon and the extinction effect of the secondary aerosol on visibility was estimated. As indicated in the analysis, the mass of secondary aerosol takes up 50% of the total mass of PM2.5; the OC/EC ratio is larger than 2 and there are significant characteristics of secondary aerosol generation; the levels of secondary OC are comparable with those of sulfate; and there is obvious enrichment of secondary aerosol on more polluted days. In a dry environment, the extinction weight is 59% for the secondary aerosol, while it is as high as 82% if the environment is highly humid (relative humidity [RH] = 95%). The hygroscopic growth of the aerosol can reduce visibility greatly; the secondary aerosol shares much larger quotas on more polluted days. For the Pearl River Delta (PRD), secondary aerosol and carbonaceous aerosol, especially secondary organic carbon (SOC), are a very acute problem; the study of the generating mechanism and sources for secondary aerosol is the key to the effort of controlling visibility in this region. The equation set forth in IMPROVE experiments can only be referenced but is not applicable to evaluate the extinction effect of individual aerosol components on visibility in the PRD region.

[Study on air quality and pollution meteorology conditions of Guangzhou during the 2010 Asian games].

Based on the monitoring data of NO2, O3, SO2, PM, visibility, regional air quality index (RAQI) and the atmospheric transport and diffusion data from Nov. 4, 2010 to Dec. 10, 2010 in Guangzhou area, the variations of air quality and meteorological conditions during the Guangzhou Asian Games were analyzed. It was found that, during the Asian Games, the air quality was better than the air quality before or after the Asian Games. The visibility was greater than the visibility before or after the Asian Games, while the concentrations of PM1 and PM2.5 were lower. The correlation coefficient between visibility and the concentrations of PM1, PM2.5 indicated anti-correlation relationships. Daily and hourly concentrations of NO2 and SO2 met the primary ambient air quality standards, whereas the daily concentration of PM10 and hourly concentration of O3 met the secondary ambient air quality standards. Pollutants had been well controlled during the Asian Games. The concentration of SO2 in Guangzhou was influenced by local sources and long distance transmission, while the concentration of NO2 was significantly influenced by local sources. The emissions of NO2, SO2 and PM10 surrounding Guangzhou had a trend to affect the concentrations in Guangzhou, but the situation of O3 was opposite, the relatively high concentration of O3 in Guangzhou had tendency to be transported to the surrounding areas. The pollution meteorology conditions in the period of Asian Games were better than the conditions before or after the Asian Games. The decrease in the concentrations during the Asian Games did not only benefit from the emission control by the government, but also from the good meteorological conditions.