PP333对水稻幼苗过氧化物酶的调节

PP333处理后,苗高明显矮化,根长则表现为低浓度促进高浓度抑制,同时苗体内过氧化物酶(POD)活性及其同工酶谱带随之发生相应变化。统计分析的结果表明:苗高与POD活性呈显著负相关(r=-0.9325);根长与POD活性呈不显著负相关(r=-0.4216)。用外源GA_3逆转PP333的抑制作用时,POD活性下降,同工酶谱带着色变浅,C_3带几乎消失,用NAA处理未见有逆转PP333的抑制效应,同时POD活性提高,同工酶谱带增加两条(B_1、C_2带)。由此可以认为:PP333对植物生长的调节作用是通过对酶的影响而实现的。     

NCT、NAA、青霉素及氨苄青霉素对菊花水培扦插生根的影响

以不同浓度梯度的NCT，NAA，氨苄青霉素和青霉素水溶液对菊花插条基部进行浸泡处理，测定了不同处理后水培扦插2周和3周时的生根状况。结果表明，NCT，NAA，氨苄青霉素和青霉素均能促进菊花插生生根，所设浓度中以NCT20mg/L,NAA10mg/L，氨苄青霉素200mg/L和青霉素10万单位／L生根效率较好。其中NAA10mg/L为最佳。从实践角度看，氨苄青霉素200mg/L和青霉素10万单位／L为上选。     

水杨酸和萘乙酸对山茱萸种子萌发的生理学影响

本文研究了外源萘乙酸和水杨酸对山茱萸种子萌发及其对抗氧化酶系的影响.结果表明,山茱萸种子经处理后,低浓度(0.01 mmol.L-1,0.05mmol.L-1)萘乙酸(NAA)和中浓度(0.01mmol.L-1~0.10mmol.L-1)水杨酸(SA)可促进山茱萸种子的萌发,其中0.01mmol.L-1NAA处理后萌发率显著提高(x2=4.667>x20.05=3.841,P<0.05)和0.05mmol.L-1SA效果显著高于对照(x2=5.093>x20.05=3.841,P<0.05),它们均提高了CAT和SOD酶的活性,改善了膜的相对透性和完整性.而中浓度和高浓度(高于1.00mmol.L-1)NAA以及低于0.01mmol.L-1或高于1.00mmol.L-1SA会抑制山茱萸种子萌发或促进萌发作用不明显.     

Characterization of carbon nanotubes and analytical methods for their determination in environmental and biological samples: A review

In the present paper, a critical overview of the most commonly used techniques for the characterization and the determination of carbon nanotubes (CNTs) is given on the basis of 170 references (2000–2014). The analytical techniques used for CNT characterization (including microscopic and diffraction, spectroscopic, thermal and separation techniques) are classified, described, and illustrated with applied examples. Furthermore, the performance of sampling procedures as well as the available methods for the determination of CNTs in real biological and environmental samples are reviewed and discussed according to their analytical characteristics. In addition, future trends and perspectives in this field of work are critically presented.     

肿瘤患者体内钠氯钾钙元素的中子活化分析

运用体内中子活化分析技术,对21例不同肿瘤患者体内钠、氯、钾、钙元素进行了研究.结果表明,肾脏肿瘤病人体内上述4种元素较其他类病人有显著亏损,这应该引起临床研究人体肿瘤工作者的注意.     

铁皮石斛种胚萌发和原球茎质量控制

本文讨论了植物生长素对铁皮石斛种胚萌发和 ABA对原球茎质量的影响. 实验结果表明 NAA 在 0. 05～ 2. 0× 10- 6范围内都能促进种胚萌发 ,而 2, 4-D促进种胚萌发的浓度范围很窄 ,仅在浓度为 0. 5× 10- 6时能促进种胚萌发; 0. 5× 10- 6 ABA则能显著促进原球茎的生长及其质量的提高.     

Determination of technetium-99 in environmental samples: A review

Due to the lack of a stable technetium isotope, and the high mobility and long half-life, ⁹⁹Tc is considered to be one of the most important radionuclides in safety assessment of environmental radioactivity as well as nuclear waste management. ⁹⁹Tc is also an important tracer for oceanographic research due to the high technetium solubility in seawater as TcO₄⁻. A number of analytical methods, using chemical separation combined with radiometric and mass spectrometric measurement techniques, have been developed over the past decades for determination of ⁹⁹Tc in different environmental samples. This article summarizes and compares recently reported chemical separation procedures and measurement methods for determination of ⁹⁹Tc. Due to the extremely low concentration of ⁹⁹Tc in environmental samples, the sample preparation, pre-concentration, chemical separation and purification for removal of the interferences for detection of ⁹⁹Tc are the most important issues governing the accurate determination of ⁹⁹Tc. These aspects are discussed in detail in this article. Meanwhile, the different measurement techniques for ⁹⁹Tc are also compared with respect to advantages and drawbacks. Novel automated analytical methods for rapid determination of ⁹⁹Tc using solid extraction or ion exchange chromatography for separation of ⁹⁹Tc, employing flow injection or sequential injection approaches are also discussed.     

Determination of Silver in Plants by Flameless Atomic Absorption Spectrometry and Neutron Activation Analysis

Abstract

Three analytical techniques suitable for determining silver concentrations in plants are presented and compared. Graphite furnace atomic absorption spectrometry performed directly on sample digests was the most sensitive and convenient. Neutron activation analysis, measuring ^110mAg gave good reproducibility, but lower sensitivity. A cyclic activation scheme to generate and detect the short-lived isotope ¹¹⁰Ag was useful as a quick reconnaissance technique, but interference from ⁷⁶As reduced its effectiveness.

Data are presented on the silver content of terrestrial plants. Background silver concentrations for lichens and bryophytes collected from Wales, U.K. were <0.07μgg^?1. Samples collected from areas contaminated by derelict metal mines contained between 0.1-1.0μAgg^?1. The aerial portions of vascular species usually contained less silver than bryophytes growing on the same substrate. Fungi are shown to bioconcentrate silver to a greater extent than cadmium, copper or lead.     

中子活化分析在鄂尔多斯地区元素分析中的应用

利用中子活化对鄂尔多斯盆地油气田上方的地质样品进行了某些元素的检测,通过实验分析,得到了该地区岩石中某些元素的含量,并对该地区的放射性元素作出了评价,绘制了样品的稀土配分模式图和评价了当地的金属矿产资源情况.结果表明,在油气田的上方,放射性元素铀呈现出负异常;钍和钾无明显异常;岩石中的其它元素和中国大陆地壳元素丰度基本...     

Conversion of brain cytosol profile from fetal to adult type during the perinatal period: Taurine-NAA exchange

Mammals face drastic environmental changes at birth. Appropriate adjustments of various systems must take place rapidly to accommodate this once in a life time event. The brain undergoes significant adjustments as well, the most obvious of which is in its need to meet the drastic increase in energy consumption at the neuronal cell membrane due to the explosive increase in neural activities after birth. Actual changes were found to be taken place in two systems, namely, acid base balance control and cytosolic energy transport. The adjustments are accomplished by converting cytosol microenvironment from a taurine rich fetal type environment to an N-acetyl-aspartate (NAA) rich adult type environment during the post-natal period. High concentrations of taurine are necessary to provide effective buffering in the fetal brain, because the fetus cannot utilize the adult type of pCO₂ dependent acid–base balance control system, namely respiration driven pCO₂ changes. To accommodate the significantly higher demand of energy consumption at the membrane due to the increased neuronal activities, taurine has to be replaced by NAA, since the latter facilitates HEP transport from mitochondria to the membrane by passive diffusion.