海洋微藻活体及乙醇固定状态下基因组DNA的微量提取方法

探讨了海洋微藻活体及固定状态下基因组DNA的提取方法,即作者改进的CTAB法.结果表明,CTAB改进法提取的基因组DNA蛋白质、酚、盐和小分子的污染较少,多糖成份也得到了有效去除.用5%乙醇固定样本提取DNA的效果最好,对原生动物抑制效果也较明显;10%以上的乙醇可杀死原生动物,但对DNA的降解率较大;30%以上的乙醇对细菌抑制较明显,但DNA都有较大程度的降解.本法提取的DNA可用于正常的酶切和PCR.用甲醛、甲醇/冰醋酸等其它固定液固定样品,DNA的得率低或者质量和纯度低.图7表1参27     

低浓度硝基苯标准样品的考核

提出了在四级站的考核项目中，在考核低浓度硝基苯标准样品时通过改进：曲线绘制方法、取过滤液方法、调pH值方法、标样稀释方法等手段提高考核结果的准确性。     

Elemental analysis of some Egyptian ores and industrial iron samples by neutron activation analysis

ＩｎｔｒｏｄｕｃｔｉｏｎＮｏｗａｄａｙｓ,ｍｏｒｅｉｎｔｅｒｅｓｔｈａｓｇｒｏｗｎｉｎｔｈｅｄｅｔｅｒｍｉｎａｔｉｏｎｏｆｔｈｅｅｌｅｍｅｎｔａｌｃｏｎｓｔｉｔｕｅｎｔｓｏｆｍｏｓｔｉｎｄｕｓｔｒｉａｌｍａｔｅｒｉａｌｓｓｕｃｈａｓｉｒｏｎｗｈｅｒｅｓｅｖｅｒａｌｄｉｆｆｅｒｅｎｔｍｅｔｈｏｄｓａｒｅｕｓｅｄ(Ｈａｓｓａｎ ,1982 ;Ａｂｄｕｌ,1990 ;Ｆａｉｌｅｙ ,1979;Ａｎｄｅｒｓｏｎ ,1981) .Ｒｅｃｅｎｔｌｙ ,ｔｈｅｒｅｗｅｒｅｍａｎｙｉｎｖｅｓｔｉｇａｔｉｏｎｓｏｎｅｌｅｍｅｎｔａｌａｎａｌｙｓｉ…     

Determination of Cd,Cr, Cu,Pb and Zn from various water samples with use of FAAS techniques after the solid phase extraction on rice bran

A facile and novel method has been developed for the determination of cadmium, chromium, copper, lead, and zinc from various water samples using FAAS. In the present investigation, a syringe was loaded with sorbent (rice bran) for the separation and enrichment of cadmium, chromium, copper, lead, and zinc, prior to their analysis by flame atomic absorption spectrometry which was described to substitute the batch and column techniques. The syringe was loaded with 2.0 g of sorbent in order to retain the analyte elements. Six milliliter of sample solution (pH 8.0 ± 0.2) was drawn into the syringe in 15 s and discharged over a period of 15 s. Then, 2.0 M HCl eluent was drawn into the syringe and ejected back to desorb the analyte elements. At the optimum conditions, the percentage recoveries of Cd, Cr, Cu, Pb, and Zn was in the range of 95.5–99.4% with SD of 0.10%. The elements could be concentrated by drawing and discharging several portions of sample successively. The detailed study of various interferences made the confirmation of the method highly selective. The risk of contamination is less than that with the column technique. The method was successfully applied for the determination of Cd, Cr, Cu, Pb, and Zn in spiked and natural water samples. The results obtained are in good agreement with the reported methods at the 95% confidence level.     

A signal-amplified whole-cell biosensor for sensitive detection of Hg2+ based on Hg2+-enhanced reporter module

A signal-amplified mercury sensing biosensor with desired sensitivity was developed through firstly using the GFP mutant with fluorescence increasing response towards Hg²⁺ as the reporter module. The developed biosensor showed response for Hg²⁺ in a relatively wide range of 1–10,000 nmol/L, and the detection limit was improved one or two orders of magnitude in comparison with most metal-sensing biosensors in similar constructs. In addition, the biosensor could distinguish Hg²⁺ easily from multiple metal ions and displayed strong adaptability to extensive pH conditions (pH 4.0–10.0). More importantly, the developed biosensor was able to provide an initial assessment of Hg²⁺ spiked in the environmental water with the recoveries between 85.70% and 112.50%. The signal-amplified strategy performed by the modified reporter module will be widely applicable to many other whole-cell biosensors, meeting the practical requirements with sufficient sensing performance.     

运用回归分析测算水口镇商业用地基准地价

惠州市惠城区水口镇原隶属于惠阳市,2003年惠城区行政区划进行了战略性调整,惠阳撤市设区,水口镇划归惠城区管辖, 这样水口镇现执行的基准地价标准(原惠阳标准)需要更新.目前基准地价的评估方法有很多种,通过建立样点地价与土地定级网格单元总分值关系模型,运用回归分析来测算水口镇商业用地基准地价.     

137Cs in marine samples from the Brazilian southeastern coastal region

The present work presents the results of ¹³⁷Cs concentration in seawater, fish and sediments samples collect in 11 sampling points, crossing the Brazilian Southeastern coastal region, from Vitória (ES) to Santos (SP), on a routine basis from 1997 to 2002. This monitoring program was carried out by the Instituto de Radioproteção e Dosimetria (IRD/CNEN/MCT), in cooperation with the Instituto de Estudos do Mar Almirante Paulo Moreira (IEAPM/Brazilian Navy), aiming at determining artificial radionuclides in marine samples. Additionally to the ¹³⁷Cs results, ⁹⁰Sr concentrations in fish samples from 1998 to 2002 are also reported.The ¹³⁷Cs in seawater follows a lognormal distribution, with a geometric mean of 1.8 Bq m^-3 and a geometric standard deviation of 1.4 (n=54), decay corrected to June/2002. For ¹³⁷Cs levels in fish samples a geometric mean of 0.19 Bq kg⁻¹ and a geometric standard deviation of 2.9 (n=39), decay corrected to June/2002, with a range of 0.03 to 1.7 Bq kg⁻¹, were obtained. Based on the ¹³⁷Cs mean concentration in fish as well as in seawater, a transfer factor of 1 × 10² was calculated, which is quite in agreement with the recommended value found in the Safety Report Serie 19.     

For What Applications Can Probability and Non-Probability Sampling Be Used?

Almost any type of sample has some utilitywhen estimating population quantities. The focus inthis paper is to indicate what type or combination oftypes of sampling can be used in various situationsranging from a sample designed to establishcause-effect or legal challenge to one involving asimple subjective judgment. Several of these methodshave little or no utility in the scientific area buteven in the best of circumstances, particularlycomplex ones, both probabilistic and non-probabilisticprocedures have to be used because of lack ofknowledge and cost. We illustrate this with a marbledmurrelet example.     

挥发酚水质样品保存条件的研究

应用正交试验法探讨挥发酚水质样品的最优保存条件，找出了对挥发酚水质样品保存影响最大的因素为保存温度，其次为样品的pH值。经实验证明，挥发酚样品浓度为0.2mg/L，温度5℃，保存时间在8h内，pH值为4的条件下，挥发酚水质样品的保存效果最好。     

环境中长寿核素的ICP-MS测量研究及进展

本文综述了ICP-MS用于环境样品中U,Np和Pu的放射性长寿命核素测定的各项相关技术以及近年来一些重要的研究和进展状况,同时对技术难点——干扰效应进行了讨论.