The mode of action and neurotoxicity of mirex,chlordecone, and four hydrogenated mirex analogs

The toxicity and neurological effects of mirex, chlordecone, and four hydrogenated mirex analogs were evaluated on the American cockroach. The severity of poisoning symptoms correlated with the ability of each compound to increase spontaneous activity and prolong synaptic afterdischarge in ganglia of the ventral nerve cord. Afterdischarge across the metathoracic ganglion was consistent with a characteristic wing splaying symptom in mirex-poisoned cockroaches. The actions of hemicholinium-3 and nicotine on nerve cords from mirex-poisoned cockroaches are described and are consistent with a hypothesis that the increased spontaneous activity and afterdischarge are the result of enhanced transmitter release in ganglia of poisoned animals.     

南京主要滨河绿地植物群落的调查

应用群落生态学方法,对南京紫霞湖、前湖、护城河与玄武湖滨河绿地植物群落的外貌、组成与结构等进行了调查。结果表明,5个绿地主要以阔叶落叶树种为主,缺少常绿树种的运用;群落结构不甚合理,乔木层相对丰富,而低矮灌木及地被层种类和数量相对缺少;人工绿地过于注重观赏品种的运用,而忽视耐水湿性种。作者认为,应结合地形和环境,合理地把握植物耐水湿性与观赏性,创造有地域特色的滨河植物景观,达到自然景观与人工景观的统一;可适当增补一些观赏性好的适生树种,提高植物景观多样性,营造城市滨河生态廊道,使其成为城市绿地系统中的组成部分。     

贺江生态游憩景观设计

合理的设计河流生态廊道,是解决当前人类剧烈活动造成的景观破碎化以及随之而来的众多环境问题的重要措施。本文从勘察与分析贺州滨江区的场地特征出发,以最少干预为原则,提出该滨水景观的设计对策:保护与修复自然河流的绿色与蓝色基底,最少量地改变原有地形和植被,同时满足城市人的休闲活动需要,创造一种当代人的景观体验空间。     

In vitro effects of malathion and O,O,S-trimethyl phosphorothioate on cytotoxic T-lymphocyte responses

Oral administration of O,O,S-trimethyl phosphorothioate (OOS), an impurity present in technical formulations of malathion, has been shown to be associated with a high incidence of pneumonia in rats and to be highly immunosuppressive in mice. Based on these findings, an in vitro model was established to study the effect of this and other organophosphorus compounds on murine cytotoxic T-lymphocyte (CTL) responses. The organophosphorus compounds were tested for their ability to block in vitro generation of CTL responses to alloantigen and/or the expression of these cytotoxic responses. Responses were generated in C57Bl/6 (H-2^b) spleen cells to mitomycin C-blocked P815 (H-2^d) tumor cells. The cytotoxicity of the cultured splenocytes to P815 target was measured using a 4-hr chromium release assay. These data demonstrated that malathion was able to block the ability of splenocytes to sensitize to P815 at concentrations as low as 25 μg/ml, but was not able to block the expression of cytotoxicity by mature killer T cells. The same was true for OOS which had been activated by preincubation with rat liver postmitochondrial supernatant (PMS). Activated OOS blocked the generation of CTL responses at concentrations as low as 75 μg/ml while having no effect on mature cytotoxic cells. In fact, both malathion and activated OOS were no longer able to suppress CTL responses if treatment was performed as early as 24 hr after exposure to antigen. Additionally, it was demonstrated that when malathion was preincubated with PMS it was no longer suppressive and that OOS without activation failed to suppress CTL responses.     

西藏高寒地区带状景观空间艺术特征营造及实践——以昌都市达玛拉滨江公园设计为例

西藏地区整体海拔较高,高寒山地、峡谷地貌较多,带状景观空间特征明显。以西藏昌都市达玛拉滨江公园在建市政项目为研究对象,对设计方案进行系统剖析,结合项目实际地貌、气候、文化等因素,分析其功能区,人口展示区、商业休闲区、休闲漫步区景观设计,植物分区设计以及配套设施设计等手法,以展示高原景观营造独特地域性特征的方法。     

生态工程方法在城市水体景观中的设计与实践

按立体设计的理念,从景观功能入手,并以南京六合区滁河景观为例引入TD(Total Design)设计理念,希望通过实例深入分析,探讨生态工程方法在城区滨河景观工程中的实践理论。     

信丰县桃江滨水空间环境景观规划研究

解析了信丰桃江滨水景观空间的规划目标及规划布局,详细介绍了各景观节点,同时分析了交通、灯光、绿化的设计思路。在尊重和充分理解规划意图的基础上,通过提炼历史元素,挖掘民俗文化特征,将当地的文化特色融入到滨水空间的设计中,力求创造富有本土文化内涵的城市滨水景观。     

镇江滨江景观带的旅游开发与建设初探

根据滨江景观建设的原则,结合镇江滨江地区景观建设现状,在分析其优势及问题的基础上,对有待开发的滨江景观带提出一些建议.     

Hydrochemical and stable isotopic assessment of nitrate contamination in an alluvial aquifer underneath a riverside agricultural field

Major ions and stable isotopic (δD_water, δ¹⁸O_water, δ¹⁵N_nitrate, δ¹⁸O_nitrate) measurements in concert with hydrochemical modeling were used in order to elucidate the sources and geochemical processes controlling nitrate contamination of shallow alluvial groundwater underneath a riverside agricultural field in the Buyeo area, Korea. Beneath vegetable fields in the sandy soil, the mean nitrate concentration of groundwater was 148.6 mg/L, which is significantly higher than in groundwater (mean 28.8 mg/L) beneath silty soils underneath rice paddy fields. Nitrogen isotope data indicate that synthetic fertilizers are the predominant source of groundwater nitrate in the study area. Denitrification during recharge through rice paddy soils appears to be responsible for the lower nitrate concentrations in groundwater beneath the silty soil zone. The relationship between nitrogen and oxygen isotope data of nitrate also suggests mixing of two different groundwater bodies with nitrates from the silt zone and the sand zone. Geochemical mass balance modeling on hydrochemical data indicates that various agricultural chemicals such as urea, lime, magnesium sulfate and potassium chloride dissolve in vegetable fields of the sandy zone, resulting in significant enrichment of various solutes such as K⁺, Ca²⁺, Mg²⁺, NO₃⁻, SO₄²⁻ and Cl⁻. As a consequence of over-utilization of synthetic nitrogen fertilizers, the sand zone is characterized by very high nitrate concentrations in the groundwater. This study suggests that a reduction of over-fertilization especially on vegetable fields in the riverside sand zone is required to minimize the nitrate contamination of groundwater. This study also shows that combination of geochemical and isotopic techniques with simple mass balance modeling provides information about the causes and processes of nitrate contamination of groundwater underneath a riverside agricultural field. The study also provides sustainable measures to optimize fertilization rate as an important basis of eco-friendly agriculture.     

中心城区园林节水型施工技术应用——以上海南园滨江绿地改扩建工程为例

以上海市黄浦区南园滨江绿地改扩建工程为例,介绍容器栽植、雨水再利用和配置节水植物等节水型施工技术在新园林建设中的使用。