Insights into pH-dependent transformation of gibberellic acid in aqueous solution:Transformation pat

来源 :环境科学学报(英文版) | 被引量 : 0次 | 上传用户:zjwx2008
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
Gibberellic acid(GA3)is widely used in agriculture and maybe transfer with groundwater flow,which is an endocrine disruptor,but few studies have focused on the transformation pathway and toxicity assessment of GA3 and its products.Here,GA3 and its transformation products in aqueous solution were identified and quantified by liquid chromatography mass spectrometry hybrid ion trap time-of-flight(LCMS-IT-TOF)and high-performance liquid chromatography(HPLC),respectively.The results showed that the half-life of GA3 trans-formation in ultrapure water was 16.1-24.6 days at pH=2.0-8.0,with the lowest half-life occurring at pH=8.0 and highest half-life occurring at pH=3.3.Isomerized gibberellic acid(Iso-GA3)and gibberellenic acid(GEA)were the main transformation products with a lit-tle hydroxy gibberellic acid(OH-GA3).In North China groundwater,the mass balance of GA3 and its products was 76.2%,including Iso-GA3(58%),GEA(7.9%),GA3(7.3%)and OH-GA3(3%)after reaching transformation equilibrium.Using Gaussian 09 for chemical computation,it was found that the transformation mechanism of GA3 was dependent upon the bond en-ergy and the stereochemical feature of its molecular structure.GA3 always isomerized from the γ-lactone ring due to the lowest bond energy between the oxygen terminus of the y-lactone ring and A ring.While GA3 and its transformation products all had developmental toxicity,the predicated LC50(96 hr)and LD50 of the main products of GA3 were much lower than those of GA3,indicating GA3 would be transformed into higher toxicity derivatives in water environments,posing a significant health risk to humans and the environment.
其他文献
The nondestructive characterization of the mixing state of individual fine particles using the traditional single particle analysis technique remains a challenge.In this study,fine particles were collected during haze events under different pollution leve
结合国际海事组织法规对船舶操纵性的相关要求,采用自由船模试验的方法对某7 800 t沥青船的Z字试验操纵性能进行了研究。通过加大舵叶面积、优化舵叶形状和增加附体等技术手段,对该船型的偏航和保向性能进行优化。船模试验结果表明:采用3号舵加附体的方案,可以确保该船的Z字操纵性能相关指标在设计阶段满足法规要求,实船的合规性也经试航得到了验证。
针对现有恶意软件分类方法融合的静态特征维度高、特征提取耗时、Boosting算法对大量高维特征样本串行训练时间长的问题,提出一种基于静态特征融合的分类方法。提取原文件和其反编译的Lst文件的灰度图像素特征、原文件的结构特征和Lst文件的内容特征,对特征融合和分类。在训练集采样时启用GOSS算法减少对训练样本的采样,使用LightGBM作为分类器,该分类器通过EFB对互斥特征降维。实验证明在三类特征融合下分类准确率达到了97.04%,通过启用GOSS采样减少了29%的训练时间,在分类效果上,融合的特征优于融
Access to safe drinking water free from microbial pollution is an issue of global concern. The use of photocatalytic thin films in water treatment has focused on titanium dioxide, which requires UV-activation, proving a potential barrier to upscaling and
作为一种新型元启发式群智能优化算法,花授粉算法具有结构简单、鲁棒性强、控制参数少,全局寻优性能好和执行效率高等特点,其具有的特性和优势,吸引了国内外众多学者对其展开研究。简单阐述了花授粉算法的设计思路,并分析了现有的对算法初始解质量、种群多样性以及搜索能力的改进以及算法在各个领域如分类、定位、路径规划、经济调控等方面的应用。分析了花授粉算法未来的可以进一步研究的方向与内容。
为了进一步完善结构共同规范(Common Structural Rules,CSR),分析了CSR关于进水工况下密性舱壁上的动载荷计算公式。以某型油船为例,对比了不同版本CSR规范下该载荷计算值的差异,研究了规范变更对结构设计的影响,分析了现行CSR规范下该载荷计算公式的特点和缺陷,并给出了相应的修正方法。
Algal organic matter(AOM),including extracellular organic matter(EOM)and intracellular organic matter(IOM)from algal blooms,is widely accepted as essential precursors of disinfection byproducts(DBPs).This study evaluated the effect of ozonation or ozone c
Chlorine dioxide(ClO2)disinfection usually does not produce halogenated disinfection by-products,but the formation of the inorganic by-product chlorite(ClO2-)is
维吾尔语具有形态丰富性、黏着性和数据稀疏性等特点,处理技术和英汉等热门语言有着较大差距并且未能满足新疆地区发展需求。形态分析是自然语言处理的重要组成部分,研究维吾尔语形态分析对于推动维吾尔语信息处理技术发展有着重要意义。简述了维吾尔语语法,描述了维吾尔语自然语言处理、形态分析及其相关基本资源研究现状,将常见方法分为基于规则、基于词典、基于统计、基于深度学习和基于混合5大类并分析了各种方法的优劣,介绍了维吾尔语形态分析后续研究,借鉴了先进的词法分析方法,总结了维吾尔语形态分析面临的挑战和机遇,并对其未来发展
为了快速将TRIBON软件中成熟的二次开发程序移植到AM软件中,通过分析TRIBON和AM这两款软件二次开发方法,对比两款软件二次开发方法的内置函数,找出两者二次开发方法的差异性