铬黑T双波长等吸收点光度法测定野菜曲麻中钙

曲麻菜学名苣荬菜,性寒味苦,具有消热解毒、凉血利湿等功效。苣荬菜含有铁、铜、镁、锌、钙、锰等多种元素,其含钙量是菠菜的3倍。钙是人体中不可缺少的微量元素,样品中钙的测定方法主要采用分光光度法[1-5],但在Mg2+、Zn2+共存时,以铬黑2+     

墓头回CO2超临界萃取物的气相色谱-质谱分析

莫头回别名箭头风、臭罐子等,系败酱科败酱属植物异叶败酱patrinia heterophylla Bge或糙叶败酱patrinia scabra Bge。根及全草入药用,能治伤寒、温疟、妇女崩中,赤白带下,跌打损伤等疾病[1],对艾氏癌细胞有抑制及伤害作用[2]。目前对其化学成分的研究已有报道[3,4],对其挥发油     

四齿四棱草根部的两个新二萜化合物

通过硅胶柱层析从我国特有属植物四齿四棱草(Schnabelia tetradonta)根部乙醇提取物中分离纯化出2个新的17(15→16)-移-20-降松香烷型二萜化合物,分别命名为四棱草内酯A和B.经波谱分析,将它们的结构确定为17(15→16)-移-20-降松香烷-12,16-环氧-7,17-二羟基-5(10),6,8,12,15-五烯-11,14-二酮-18(1)-内酯(1)和17(15→16)-移-20-降松香烷-12,16-环氧-7-羟基-5(10),6,8,12,15-五烯-11,14-二酮-18(1)-内酯(2).具有这种分子骨架的二萜化合物为首次报道.     

卟啉降冰片烯聚合物的合成、表征及性质研究

本文设计合成了卟啉的降冰片烯单体,采用Grubbs催化剂与长链烷基的降冰片烯单体开环易位聚合,直接得到了卟啉降冰片烯聚合物,通过紫外-可见吸收光谱、荧光光谱、电化学等手段研究了卟啉降冰片烯聚合物的性质,与小分子单体相比,所得卟啉高分子共聚物相当好地保持了卟啉应有的光物理、电化学等特性.     

高效液相色谱法测定氟草烟在大蒜、玉米中的残留

氟草烟(ISO通用名称fluroxypyr),又称氯氟吡氧乙酸、使它隆、治莠灵,是美国陶氏化学公司开发的一种内吸传导型苗后除草剂,在我国一些地区广泛使用。有人采用气相色谱法对氟草烟在植物中的残留进行分析．但样品需首先经甲酯化衍生处理。也有人采用高效液相色谱法分析氟草烟,但操作繁杂。我们在反相高效液相色谱体系中建     

植物墓头回中总皂甙的提取与含量测定

墓头回系败酱科败酱属植物，有异叶败酱patrinia heterophylla Bge和糙叶败酱patrinia scabra Bge。分布于陕西、河南、河北、山西等地。根及全草入药用。其中含挥发油、黄酮、皂甙、萜类等多种化学成分，临床上用于治疗急性阑尾炎初起，瘰疬等症。有效成分主要是以齐墩果酸苷元和常春藤苷元组成的三萜皂甙，其总皂苷具有抗肿瘤等作用。目前对齐墩果酸苷含量的测定已有报道。本文建立用比色法测定墓头回中总皂甙含量的方法，并对5种不同产地墓头回植物不同部位中总皂甙的含量进行了测定。     

磺化木犀草素金属配合物的合成及抗氧化、抗菌活性研究

利用木犀草素、硫酸和金属盐为原料,合成了4种木犀草素磺酸金属配合物,利用红外光谱、元素分析、核磁共振光谱和质谱等手段表征了配合物的结构.以DPPH清除率、抑菌环的大小检测配合物的抗氧化、抗菌活性,结果表明木犀草素磺酸金属配合物对DPPH的清除率和对金黄色葡萄球菌和大肠杆菌的抑制作用随浓度的增大而提高,且效果优于母体木犀草素。     

白花败酱草中异牡荆苷和异荭草苷的高速逆流色谱分离和制备

应用高速逆流色谱分离制备白花败酱草中的异荭草苷和异牡荆苷,以乙酸乙酯：乙醇：水（4：1：5）为两相溶剂系统,上相为固定相,下相为流动相,流速2．0mL/min,主机800r／min,检测波长254nm。以此分离条件经一步洗脱,从300mg白花败酱草粗提物中制备得到异荭草苷24．1mg和异牡荆苷49．8mg,产物纯度经HPLC检测高达98．0％,结构经UV、IR、MS、^1HNMR和^13C NMR鉴定,二者均为首次从败酱属植物中分离得到。     

白花败酱矿物质元素分析与利用

目的对野生白花败酱与栽培白花败酱8种矿物质元素进行了测定、分析与利用。方法采用火焰原子吸收分光光度法。结果白花败酱的嫩茎叶含有丰富的K、Ca、Na、Mg常量元素和Fe、Mn、Cu、Zn微量元素,栽培种的Mn含量是野生种的4倍多。结论白花败酱可作蔬菜食用,同时对土壤中的Mn有富集能力。     

水稻(Oryza sativa L.)诱导胞核雄性不育突变体的细胞学观察

本文对由隐性单基因控制的水稻胞核雄性不育系(GMS)花粉败育的细胞学基础进行了观察.可染花粉败育型(SPA)、部分花粉败育型(PPA)、完全花粉败育型(CPA)和无花粉型(NP)等四种胞核雄性不育类型同原种M-101作了比较.减数分裂期间染色体行为观察和四分体分析表明,明显的染色体畸变同胞核雄性不育系的不育性有密切的关系.这些不育系在花粉发育期间发生的细胞学异常性远较已报道的水稻胞质雄性不育系(CMS)深刻而广泛.自减数分裂阶段以前到减数分裂阶段以后,在本试验至少看到了13种异常性.小孢母细胞拟胞质团、粘连花粉和花粉溶解等现象的存在,暗示花药壁层特别是绒毡层将同时发生异常性。     

The energy pump and the origin of the non-equilibrium flux of the dynamical systems and the networks

The global stability of dynamical systems and networks is still challenging to study. We developed a landscape and flux framework to explore the global stability. The potential landscape is directly linked to the steady state probability distribution of the non-equilibrium dynamical systems which can be used to study the global stability. The steady state probability flux together with the landscape gradient determines the dynamics of the system. The non-zero probability flux implies the breaking down of the detailed balance which is a quantitative signature of the systems being in non-equilibrium states. We investigated the dynamics of several systems from monostability to limit cycle and explored the microscopic origin of the probability flux. We discovered that the origin of the probability flux is due to the non-equilibrium conditions on the concentrations resulting energy input acting like non-equilibrium pump or battery to the system. Another interesting behavior we uncovered is that the probabilistic flux is closely related to the steady state deterministic chemical flux. For the monostable model of the kinetic cycle, the analytical expression of the probabilistic flux is directly related to the deterministic flux, and the later is directly generated by the chemical potential difference from the adenosine triphosphate (ATP) hydrolysis. For the limit cycle of the reversible Schnakenberg model, we also show that the probabilistic flux is correlated to the chemical driving force, as well as the deterministic effective flux. Furthermore, we study the phase coherence of the stochastic oscillation against the energy pump, and argue that larger non-equilibrium pump results faster flux and higher coherence. This leads to higher robustness of the biological oscillations. We also uncovered how fluctuations influence the coherence of the oscillations in two steps: (1) The mild fluctuations influence the coherence of the system mainly through the probability flux while maintaining the regular landscape topography. (2) The larger fluctuations lead to flat landscape and the complete loss of the stability of the whole system.     

New study of the stability and of the spectroscopy of the molecular anions NCO- and CNO-

Using highly correlated wave functions, the ground and the low lying excited states of the molecular NCO(-) and CNO(-) anions have been reinvestigated. The stability of the electronic ground state of the two isomers with respect to dissociation and to electron detachment has been checked along the isomerization pathway. The regions of stability of the excited electronic states have been analyzed and identified and it is shown that only the ground state is stable and the corresponding potential energy surface presents three equilibrium positions. The rovibronic spectroscopy of the X (1)Σ(+) state of both NCO(-) and CNO(-) isomers has been determined by a variational approach leading to remarkable agreement with experimental data.     

Analysis and assessment of the occurrence, the fate and the behavior of nanomaterials in the environment

Nanomaterials have one dimension <100 nm and possess physico-chemical properties dictated by their unusually small size, large surface area, shape and chemical composition. New properties of nanomaterials have boosted their production and industrial applications in many fields (e.g., microelectronics, catalysis, fuel cells, materials science, textiles, biotechnology and medicine). In biomedical fields, nanomaterials are of the appropriate dimensions to interact with biological matter. However, they may also have negative effects on biological systems. Nanotechnology is a major, innovative, scientific and economic growth area, but the increasing production and use of nanomaterials have led to calls for more information regarding the potential impacts that their release may have on human health and the environment.This review addresses analytical approaches for characterization and quantification of nanomaterials in the environment and recent studies on their occurrence, fate and behavior.     

Influence of the molecular structure and the nature of the solvent on the absorption and fluorescence characteristics of rhodamines

A study of the equilibrium of the molecular forms of rhodamine 19 in aqueous and ethanolic solution is carried out by determining the absorption and fluorescence characteristics of the zwitterionic and the cationic forms of the dye. The optical properties of rhodamine 19 are compared with those obtained for rhodamine 6G and also with those previously reported for rhodamine 3B and for the molecular forms of rhodamine B in water and ethanol. Different aspects of the molecular structure of the rhodamines and solvent effects are discussed, as well as their influence on the photophysical properties of the rhodamines. The aggregation of the molecular forms of rhodamine 19 is also studied in water and ethanol.     

Isolation and identification of the anti-isohumulones and the anti-acetylhumulinic acids

The anti-isohumulones [5-(3-methylbutanoyl)-2-(3-methylbut-2-enyl)-4-hydroxy-4-(4-methylpent-3-enoyl)-cyclopentane-1,3-diones] and the anti-acetylhumulinic acids [5-(3-methylbutanoyl)-2-(3-methylbut-2-enyl)-4-ethanoyl-4-hydroxy-cyclopentane 1,3-diones] have been isolated from an isomerisation reaction mixture of humulone [2-(3-methylbutanoyl)-4,6-di(3-methylbut-2-enyl)-6-hydroxy-cyclohexane-l,3,5-trione] by counter-current distribution and identified by spectroscopic techniques. The formation mechanism is presented and the stereochemical consequences are discussed. The anti-isohumulones are the most bitter hop compounds presently known.     

Synthesis and pharmacological effects of the enantiomers of the N-phenethyl analogues of the ortho and para e- and f-oxide-bridged phenylmorphans

The N-phenethyl analogues of (1R*,4aR*,9aS*)-2-phenethyl-1,3,4,9a-tetrahydro-2H-1,4a-propanobenzofuro[2,3-c]pyridin-6-ol and 8-ol and (1R*,4aR*,9aR*)-2-phenethyl-1,3,4,9a-tetrahydro-2H-1,4a-propanobenzofuro[2.3-c]pyridin-6-ol and 8-ol, the ortho- (43) and para-hydroxy e- (20), and f-oxide-bridged 5-phenylmorphans (53 and 26) were prepared in racemic and enantiomerically pure forms from a common precursor, the quaternary salt 12. Optical resolutions were accomplished by salt formation with suitable enantiomerically pure chiral acids or by preparative HPLC on a chiral support. The N-phenethyl (-)- para-e enantiomer (1S,4aS,9aR-(-)-20) was found to be a mu-opioid agonist with morphine-like antinociceptive activity in a mouse assay. In contrast, the N-phenethyl (-)-ortho-f enantiomer (1R,4aR,9aR-(-)-53) had good affinity for the mu-opioid receptor (K(i) = 7 nM) and was found to be a mu-antagonist both in the [(35)S]GTP-gamma-S assay and in vivo. The molecular structures of these rigid enantiomers were energy minimized with density functional theory at the level B3LYP/6-31G* level, and then overlaid on a known potent mu-agonist. This superposition study suggests that the agonist activity of the oxide-bridged 5-phenylmorphans can be attributed to formation of a seven membered ring that is hypothesized to facilitate a proton transfer from the protonated nitrogen to a proton acceptor in the mu-opioid receptor.     

Phospholipid and fatty acid compositions of the lipids of the eggs and caterpillars of the silkworm,and of artificial diets and their components

The lipids of silkworm eggs in the period of diapause and embryonic and postembryonic development, of artificial feeds, and of the main lipid-containing components of artificial nutrient media have been investigated.     

Phospholipid and fatty acid compositions of the lipids of the eggs and caterpillars of the silkworm, and of artificial diets and their components

The lipids of silkworm eggs in the period of diapause and embryonic and postembryonic development, of artificial feeds, and of the main lipid-containing components of artificial nutrient media have been investigated.Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 192–197, March–April, 1994.