ABSTRACT
An analytical method was developed for the simultaneous extraction and determination of three quaternary ammonium compouds ( QACs) in soil samples using ultrasonic extraction and gas chromatography-mass spectrometry( GC-MS) . The qualitative and quantitative analysis of the three analytes dodecyltrimethyl ammonium chloride ( DTAC) , cetyltrimethyl ammonium bromide ( CTAB) and didodecyldimethyl ammonium chloride ( DDAC) were conducted by application of EI mass spectra and selected ion monioring ( SIM ) . Characteristic ions of the QACs were m/z 58 ( DTAC and CTAB) and m/z 212 ( DDAC) . To achieve optimum extraction efficiency, several impact factors including types of extractants, pH of extraction, concentration of linear alkylbenzene sulfonates ( LAS) , extraction times and content of purification column were investigated. Methanol with pH 3. 5 and 40 μg/L LAS solution were selected as extractant. Soil sample was extracted by treated methanol each 10 mL for 20 min every time. Extract of the soil sample was purified by neutral alumina column with 4 cm in length and 1cm in diameter, and then was determineted by GC-MS. Good linear relationships of all the three QACs were obtained in the range of 0. 02-2. 0 mg/L. The limits of determination (LOD, S/N=3) was 1. 2-4. 5 μg/kg. The method was used to analyse real soil samples ( paddy soil, lateritic red soil, and ore tailings) collected from a mining district in south China. Results of determination exhibited the concerntrations of the three analytes in real soil samples ranged from 0 . 24 mg/kg to 0. 41 mg/kg, and their recoveries ranged from 76% to 113% with relative standard deviations ( RSD) of 1. 1%-12. 9% in three different spiked concentrations of 0. 2, 0. 5 and 1. 0 mg/kg.
ABSTRACT
Objective To understand the depression status and its influencing factors of Chenzhou rural widowed elderly with different genders.Methods A random sample of 342 widowed elderly from 30 villages was investigated using the Geriatric Depression Scale and a self-designed questionnaire.Results Widowed elderly depression detection rate was 29.8％,depressive symptoms among elderly women detection rate was 34.7％,higher than men's depressive symptoms detection rate,which was 22.9％.Binary Logistic regression analysis showed:Alone,decreased self-care ability was the common risk factors of depressive symptoms of widowed elderly.The impact on men was bigger than on female.Age,chronic diseases were the main factors affecting depression status of elderly men,and economic security was the main factors affecting the depression status of elderly women.Conclusions The incidence of depressive symptoms in rural widowed elderly is high,but there are differences between widowed elderly with different genders in depression status and influencing factors.Therefore the community workers need to take targeted interventions to promote mental health for the elderly.
ABSTRACT
Objective To explore a venipuncture method that can reduce the pain, improve the suc-cess rate of puncture as well as reduce vascular injury. Methods Self-controlled method was applied in 200 patients, needle tips with 20～25°,31～40°,41～50°, 51～60°, > 60° angles on the top of the blood ves-sels,the inclined plane of the needle parallel to the longitudinal axis of the blood vessel (that was,the in-clined plane to the left or right) or traditional method with upward of needle tips were adopted, the observa-tion group and the control group were divided according to different methods, pain and success rate of puncture were compared. Results There were differences between the two groups,results of the observa-tion group were better than those of the control group (except when > 60°, success rate showed no differ-ence). Conclusions Venipuncture with needle tip parallel to the longitudinal axis of the blood vessels can significantly reduce pain in patients, improve the success rate of puncture and reduce the vascular in-jury, which were superior to the traditional venipuncture method. Whatever method is chosen, 51～60° is the best angie into the vessel.
ABSTRACT
We analyszed 108 examination papers that were taken when the students of 8 groups had finished theexercitation. The attainment was 73.6?4.4 points. Among the 400 selective questions, the difficult questions whichwere concentrated only on a few diseases accounted for 35.3%. There was mush difference between the proportion of theselective questions and that of the demands of the teaching program in different system of diseases. There was few or noselective question in the important diseases of the teaching program. It is suggested that the proposition of difficultquestions must include the important diseases in the teaching program. The diseases that are not commonly encountereddiseases may be deleted from the teaching program, but the commonly encountered must be put in the teaching program.It is necessary to reinforce the ability of students to analyse and resolve problems[