贵阳市大气黑碳污染特征

利用连续颗粒物采样仪(URG Model 2000-01J)和黑碳仪(Aethalometer)对贵阳市城区2008年9-11月大气黑碳浓度进行了连续观测,结果表明,贵阳市城区秋冬季大气24 h黑碳浓度变化范围为1.6～12 μg·m-3,平均值为4.1 μg·m-3;12 h黑碳浓度观测值主要分布在2～5 μg·m-3,白昼黑碳浓度变化范围介于1.9～9.2 μg·m-3,平均值3.9 μg·m-3,夜间黑碳浓度变化范围0.48～15 μg·m-3,平均值4.3 μg·m-3;黑碳浓度与大气PM2.5浓度变化一致,呈正相关关系(r=0.84,P＜0.0001,n=178),大气黑碳浓度的变化趋势还明显受相对湿度、温度和风速的影响.     

贵州某燃煤电厂周边春季大气颗粒物的汞污染特征

为分析燃煤电厂周边不同粒径大气颗粒物及其中汞的污染特征,于2017年春季对贵州某燃煤电厂周边TSP、PM_(10)、PM_(2.5)进行样品采集,应用冷原子荧光汞分析仪对颗粒物中汞的浓度进行测定。结果表明:TSP、PM_(10)、PM_(2.5)的体积浓度范围分别为83.7~162、65.2~130、43.6~87.1μg·m-3,超标率分别为0、5.63%、25.7%。汞的体积浓度(Cv(Hg))分别为68.5~102、58.9~84.9、51.4~80.9 pg·m~(-3);汞的质量浓度(Cm(Hg))分别为571~810、627~913、693~1083 ng·g~(-1);从空间分布看,上风向颗粒物样品中汞浓度低于下风向,主导风向高于非主导风向,主要受当地风向和采样点位置影响。汞在颗粒物中的PM_(2.5)/PM_(10)和PM_(10)/TSP值分别为67.5%~95.2%、83.1%~98.8%,明显高于其相应的颗粒物质量浓度比值,表明汞主要在细颗粒物中富集。     

青藏高原东南缘贡嘎山地区大气总汞时间序列分析及其影响因子

使用Tekran 2537A大气汞自动分析仪对中国科学院贡嘎山高山生态系统观测试验站磨西基地站(102°72′E29°92′N)进行了为期1a的大气总汞(TGM)高时间分辨率观测。研究区域的平均TGM浓度为(4±1.38)ng m-3(N=57310),高于全球大气总汞背景值1.5~2.0ng m-3。不同季节表现出相似的日变化模式,即白天相对夜晚具有较高的TGM浓度,最大TGM浓度出现在中午,最小值出现在日出前,春季和夏季日变化高峰值出现时间比秋季和冬季早1~2h。以冬季TGM浓度最高,为(6.13±1.78)ng m-3;夏季最低,为(3.17±0.67)ng m-3。观测期间不同风向间TGM浓度无显著差异。相关分析表明,TGM浓度与温度、饱和水汽压、降水量、紫外辐射、大气压有显著相关性,这种相关性随季节而变化。贡嘎山地区大气汞浓度主要受局地源的影响和调节。     

基于卫星遥感的宁夏PM_(10)时空变化特征分析

为摸清宁夏地区2013年以来大气环境的变化情况,利用MODIS卫星遥感AOD数据、气象数据及同期地面观测的PM10质量浓度数据,采用地理加权回归方法构建宁夏地区PM10遥感估算模型,分析了2013—2016年宁夏地区PM10时空变化特征。结果表明:从空间分布上看,2013—2016年,宁夏地区PM10空间差异较为明显,南部六盘山区域和西北边缘贺兰山区较低,中部半干旱区和北部引黄灌区较高;宁夏地区PM10浓度年均值为100μg·m-3,区域内年均值分布范围在76~127μg·m-3;年内季节差异明显,冬季最高,春季次之,夏季最低;从时间变化趋势上看,2013—2016年总体呈下降趋势,下降趋势为每年15.8μg·m-3;区域间差异呈减少趋势,PM10浓度年均值区域方差下降速率为每年2.8μg·m-3。     

城市公园大气颗粒物浓度的节假日特征

以杭州西湖风景区花港观鱼公园为研究对象,对比分析节假日与非节假日公园内大气颗粒物（PM2.5、PM10）浓度与游客量、气象因子、植物群落类型的相关性,并从宏观—中观—微观3个层次探究花港观鱼公园大气颗粒物浓度的节假日特征,为城市公园的科学建设提供参考和依据。研究发现：大气颗粒物浓度有明显的节假日效应。宏观方面,杭州主城区元旦节期间大气污染物主要是PM2.5和PM10,节日期间的平均浓度分别为102±41.51μg.m-3、155±64.86μg.m-3,分别是非节日的1.6倍、1.7倍。杭州主城各区受节日影响较大的是余杭区、萧山区和下城区。中观方面,花港观鱼公园节日期间PM2.5和PM10有波峰现象且振幅剧烈呈锯齿状;非节日期间午后出现波谷,上下振幅较小,其影响因子特征表现为：节日期间游客量与大气颗粒物浓度相关性较高,游客游览观光活动对PM10的贡献率更大;气象因子对PM10的影响比PM2.5显著。微观方面,公园内3种不同植物群落类型绿地的PM2.5浓度表现为：密林>纯林>草坪。     

阜新市PM2.5 污染特征及影响因素分析

运用阜新市2014 年PM2.5 质量浓度和气象数据, 经过整理分析及量化计算, 得到阜新市的PM2.5 污染时空分布特征及影响因素。结果表明, 阜新市PM2.5 污染在时间序列上呈季节性变化, 冬季均值最高为76.4 μg·m^–3, 夏季最低为41.8 μg·m^–3, 春季和秋季分别为53.6 μg·m^–3 和52.9 μg·m^–3, 一天中9 点、20 点为PM2.5 浓度值高峰时段。空间上, 阜新市自东向西PM2.5 污染逐渐加重, 但位于主城区的“长青街”点位附近PM2.5 质量浓度值均较高; 通过多因素相关分析可知PM2.5 污染分布及变化趋势是污染源排放及气象因素共同作用的结果, 在影响PM2.5 质量浓度的气象因素中, 相对湿度和气压与PM2.5 质量浓度正相关, 气温、风速和降水与PM2.5 质量浓度负相关。偏相关分析结果显示除气压外, 各气象要素间相互影响, 因此可通过建立气象要素与PM2.5 质量浓度估算模型在低浓度区估算PM2.5 质量浓度。     

细颗粒物(PM2.5)与植被关系的研究综述

细颗粒物即PM,2.5,粒径小,沉降困难,危害严重,植被在一定程度上有助于减轻颗粒物污染.本文从阐述PM2.5的沉降机理出发,分析PM2.5与植被之间的相互作用.植被的阻滞吸收作用对大气颗粒物移除存在积极影响,而过多的空气颗粒物滞留对植物生长起到一定的负面作用,但以植被对大气颗粒物的移除为主导作用.以此为基础,从林分尺度-环境特性、单木尺度-树种特性和叶片尺度-颗粒物种类和分布特性这3个角度出发,结合外界影响因素(气象学要素、空气动力学要素、大气颗粒浓度水平、植物物候变化)、气室实验以及滞留颗粒物特征等阐述植被林冠、枝干及叶片等对移除PM2.5的影响.最后,文章指出今后的研究应当向定量化方向发展,注重不同树种移除PM2.5能力的对比分析及系统研究,并针对研究区域确定防治大气PM2.5污染的优势树种.     

林带内PM_(10)、PM_(2.5)污染特征及其与气象条件的关系

为了研究林带对颗粒物的阻滞作用,2013年5月在北京市北五环南侧奥林匹克森林公园南园生态廊道附近观测不同林带内PM10与PM2.5的浓度变化以及气象因素,分析林带内外的PM10和PM2.5的浓度变化特征,以及气温、相对湿度对其影响。结果表明:PM10与PM2.5的变化规律基本一致,7:00左右最高,17:00左右出现最低值;林带对PM10的阻滞作用明显;林带对PM2.5的阻滞作用比较复杂,榆树林带和混交林带内PM2.5浓度降低,但杨树林带情况完全相反,林带内PM10和PM2.5的浓度随气象因素变化而变化,二者与气温呈负相关,气温升高,大气垂直对流作用加剧,有利于颗粒物扩散,PM10和PM2.5浓度降低;PM10和PM2.5的浓度与相对湿度呈正相关。     

夜郎湖水库水体不同形态汞的时空分布

于2006年7月(夏季)、2007年1月(冬季)和3月(春季)采集了贵州省夜郎湖水库水样,研究了不同形态汞(总汞、溶解态汞、颗粒态汞)的时空分布特征及其影响因素.结果表明,夏季水体总汞、溶解态汞、颗粒态汞平均含量分别为4.48±2.59、2.37±1.40、2.11±1.86 ng·L-1,均显著高于冬季和春季(P＜0.001),而冬春2季不同形态汞含量无明显差异.水质参数悬浮颗粒物(SPM)和硝酸盐(NO-3)与不同形态汞之间均存在显著的正相关关系,表明这些参数对于不同形态汞的季节分布起着重要作用.夏季农业耕作活动相对活跃,表层土壤的扰动增加,雨水冲刷农田土壤,带进大量的外源颗粒物,致使夜郎湖水体夏季总汞水平较高.空间分布表明,夜郎湖水库夏季总汞平均浓度从水库入库河流至大坝方向、出库河流呈现总体下降的分布趋势,但水体各采样剖面没有明显的分布规律.     

基于干沉降模型的北京平原区造林削减PM_(2.5)效应评估

本文基于干沉降模型对北京市平原区造林削减PM2.5效应进行了评估。结果表明:2012年所造森林PM2.5年削减量可达451 t,其中,阔叶林削减量占57%;不同季节的削减量有较大差别,春季的削减量占全年的50%;造林工程可使造林区PM2.5浓度平均下降0.57μg·m-3,完成《北京市2013—2017年清洁空气行动计划》目标的2%;平原区造林对于减缓和控制PM2.5、改善城市大气环境质量具有一定作用,在目前治理PM2.5有效方法不多的状况下,应当继续开展平原区造林。     

Role for dopamine in malonate-induced damage in vivo in striatum and in vitro in mesencephalic cultures

Defects in mitochondrial energy metabolism have been implicated in the pathology of several neurodegenerative disorders. In addition, the reactive metabolites generated from the metabolism and oxidation of the neurotransmitter dopamine (DA) are thought to contribute to the damage to neurons of the basal ganglia. We have previously demonstrated that infusions of the metabolic inhibitor malonate into the striata of mice or rats produce degeneration of DA nerve terminals. In the present studies, we demonstrate that an intrastriatal infusion of malonate induces a substantial increase in DA efflux in awake, behaving mice as measured by in vivo microdialysis. Furthermore, pretreatment of mice with tetrabenazine (TBZ) or the TBZ analogue Ro 4-1284 (Ro-4), compounds that reversibly inhibit the vesicular storage of DA, attenuates the malonate-induced DA efflux as well as the damage to DA nerve terminals. Consistent with these findings, the damage to both DA and GABA neurons in mesencephalic cultures by malonate exposure was attenuated by pretreatment with TBZ or Ro-4. Treatment with these compounds did not affect the formation of free radicals or the inhibition of oxidative phosphorylation resulting from malonate exposure alone. Our data suggest that DA plays an important role in the neurotoxicity produced by malonate. These findings provide direct evidence that inhibition of succinate dehydrogenase causes an increase in extracellular DA levels and indicate that bioenergetic defects may contribute to the pathogenesis of chronic neurodegenerative diseases through a mechanism involving DA.     

Scurvy in capybaras bred in captivity in Argentine

In order to determine if the absence of vitamin C in the diet of capybaras (Hydrochoerus hydrochaeris) causes scurvy, a group of seven young individuals were fed food pellets without ascorbic acid, while another group of eight individuals received the same food with 1 g of ascorbic acid per animal per day. Animals in the first group developed signs of scurvy-like gingivitis, breaking of the incisors and death of one animal. Clinical signs appeared between 25 and 104 days from the beginning of the trial in all individuals. Growth rates of individuals deprived of vitamin C was considerably less than those observed in the control group. Deficiency of ascorbic acid had a severe effect on reproduction of another population of captive capybaras. We found that the decrease in ascorbic acid content in the diet affected pregnancy, especially during the first stages. The results obtained suggest that it is necessary to supply a suitable quantity of vitamin C in the diet of this species in captivity.     

Changes in lactate dehydrogenase activity in chicken tissues in hyperthyreosis in ontogenesis

The lactate dehydrogenase activity in reactions of lactate oxidation and synthesis was studied in subfractions of the chicken brain, heart and liver at the embryonal, early postembryonal and adult stages of development after thyroxine administration. It has been shown that during embryogenesis thyroxine predominantly enhanced the rate of lactate oxidation in the mitochondrial tissues. A marked increase in the lactate synthesis was found in cytoplasm of the adult chicken tissues. Specificity of enzyme activity alterations was detected in the chicken brain during ontogenesis after thyroxine administration.     

SSTR5 ablation in islet results in alterations in glucose homeostasis in mice

Somatostatin (SST) peptide is a potent inhibitor of insulin secretion and its effect is mediated via somatostatin receptor 5 (SSTR5) in the endocrine pancreas. To investigate the consequences of gene ablation of SSTR5 in the mouse pancreas, we have generated a mouse model in which the SSTR5 gene was specifically knocked down in the pancreatic beta cells (betaSSTR5Kd) using the Cre-lox system. Immunohistochemistry analysis showed that SSTR5 gene expression was absent in beta cells at three months of age. At the time of gene ablation, betaSSTR5Kd mice demonstrated glucose intolerance with lack of insulin response and significantly reduced serum insulin levels. Insulin tolerance test demonstrated a significant increase of insulin clearance in vivo at the same age. In vitro studies demonstrated an absence of response to SST-28 stimulation in the betaSSTR5Kd mouse islet, which was associated with a significantly reduced SST expression level in betaSSTR5Kd mice pancreata. In addition, betaSSTR5Kd mice had significantly reduced serum glucose levels and increased serum insulin levels at 12 months of age. Glucose tolerance test at an older age also indicated a persistently higher insulin level in betaSSTR5Kd mice. Further studies of betaSSTR5Kd mice had revealed elevated serum C-peptide levels at both 3 and 12 months of age, suggesting that these mice are capable of producing and releasing insulin to the periphery. These results support the hypothesis that SSTR5 plays a pivotal role in the regulation of insulin secretion in the mouse pancreas.