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The purpose of this study was to investigate the blood levels of methadone in participants receiving methadone for the treatment of opioid dependence. After stabilization on methadone for four weeks, blood samples from 95 participants were collected between treatment weeks 4 and 12, before and after receiving doses of methadone, and its blood levels were measured. A multiple linear regression model was used to examine the association between methadone blood levels and the outcomes of methadone maintenance treatment (MMT). Outcome differences between participants who had high (≥2) or low (2 was significantly poorer than those whose ratio was

ObjectiveThe aim of this study was to evaluate the risk factors associated with dropout from Methadone Maintenance Treatment (MMT) clinics within a 1 year follow-up cohort study in China.MethodsA data analysis is to explore the adherence of MMT during one year from three hundred and twenty patients with heroin dependence at five clinics (3 in Shanghai, 2 in Kunming) in China. All participants were from the part of China-United States cooperation project entitled "Research about improving the compliance and efficacy of methadone maintenance treatment in China". Our data analysis includes the patients' attendance in the 6 months clinical study and the data in another 6 months afterward. The data of patients at baseline were collected with the Addiction Severity Index (ASI) which is a semi-structured questionnaire covering socio-demographic characteristics and drug use history. The one year attendance after recruitment at the clinics and daily dose were abstracted from the MMT clinic register system. The Cox proportional hazards model were used to explore the risk factor of dropout, defined as seven consecutive days without methadone.ResultsBy the end of 1 year of treatment 86 patients still remained in MMT without dropout (87% in Shanghai and 13% patients in Kunming). Over the entire 1-year period the median days of remaining in the program were 84 days (in Shanghai and Kunming were 317 days and 22 days).The factors associated with retention included age (HR=0.98, 95%C.I.:0.96-0.99, P=0.0062) and ASI alcohol scores (HR=5.72, 95%C.I.:1.49-21.92, P=0.0109) at baseline.ConclusionOne year retention of newly recruited patients with heroin dependence was related to age and ASI alcohol scores at baseline. The adherence is poorer for the patients who are young and having more serious alcohol problems.

Solid solution and coupling precipitation behavior of multiple microelements in 50CrVA spring steel under different temperatures were analyzed based on thermodynamics. Quantitative relationships between the multiple microelements' contents and secondary phases, and their effects on fatigue life, were systematically studied in conjunction with the secondary phase microstructure characterization using scanning and transmission electron microscopy, etc. The solid solution contents of different microelements decreased as the temperature decreased, especially N and Ti, but the number of compounds gradually increased when the temperature decreased. Carbonitride constitutional liquation occurred in 50CrVA-S1# spring steel-containing microparticles, and without carbonitrides, constitutional liquation occurred in 50CrVA-S2# spring steel-containing nanoparticles. The experimental results indicate that the fatigue life reduces by about an order of magnitude when the secondary phase size changes from nanometers to microns, and the corresponding relationship among multiple microelements, microstructure of secondary phases, and fatigue life, was established in this spring steel., Competing Interests: The authors declare no conflicts of interest.

Objective: To analyze the concentration of 34 kinds of elements in drinking water in Beijing., Methods: From September 15 th to 20 th, 2016, 92 families from four directions in Beijing urban area were randomly selected and drinking water from them were collected. In 24 of the 92 families, water samples were also collected from water treatment devices. The concentrations of 17 kinds of elements were determined then evaluated., Results: The concentration of 17 kinds of elements meet the hygiene standards of drinking water in all of the drinking water samples except that the iron and mercury concentration of one sample exceed the quality limits. The central water supply 18 kinds of elements detection rate was 3. 1%-63. 1%, the detection rate of 16 kinds of rare earth elements was 47. 6%-100%. Secondary water supply 18 kinds of elements detection rate was 3. 7%-63. 0%, 16 kinds of rare earth elements in the detection rate of 48. 9%-100%. Water treatment devices 18 kinds of metal elements detection rate was 4. 2%-75. 0%. The silver concentration in water samples from water treatment devices and secondary water was significantly higher than that from central water supply( F&#95;(Ag)= 4. 21, P < 0. 05), no significant difference was observed in the rest of the 33 elements in watersamples from different water supply significant difference in the concentration of element selenium, nickel and iron was observed among the water samples from four different directions of Beijing( F&#95;(Se)= 3. 64, P < 0. 05; F&#95;(Ni)= 3. 38, P < 0. 05; F&#95;(Fe)= 3. 83, P <0. 05)., Conclusion: The water quality of central water supply samples and secondary drinking water supply samples in Beijing met the hygiene standards.

Objective: To establish a new rapid method for determination of 7elements( arsenic, selenium, mercury, cadmium, chromium, lead and silver) in two kinds of chemical water treatment agents polyaluminium chloride and iron sulfate by inductively coupled plasma mass spectrometry( ICP-MS)., Methods: Pure water was added to two kinds of chemical water treatment agents. Nitric acid was added to the solution, and the solution was incubated by water bath for 1 h. Matrix effects was eliminated by the employment of Sc, Y, In and Bi as internal standards. The concentrations of 7 elements were determined., Results: The linear ranges for 7 elements were between 0 and 50. 0μg/L with a correlation coefficient for each element of higher than 0. 999. The detection limits were between 0. 05 and 0. 96 μg/L, the recoveries were between 90. 1% and106. 4%, the relative standard deviations were between 1. 6% and 5. 7%. The concentration of arsenic, selenium, and lead in certain samples of the 40 samples tested did not meet the health standards. The large majority of the unqualified samples were caused by the concentration of element lead., Conclusion: This method is simple, rapid, accurate and sensitive. It is very suitable for the determination of multi-elements inchemical water treatment agents.

Objective: To establish a method to determine the presence and concentration of DEP, DMDTP, DEDTP, PNP, CMHC and TCPY organophosphorus pesticides metabolites in human urine by LC-MS/MS., Method: 2.0 ml of urine was enzymatically hydrolyzed in water bath 37 degrees C for 4 hours, then the urine samples were solid-phase extracted by Oasis HLB and eluted with methanol, after centrifugation and concentration the urine samples were separated on waters symmetry C18 5 microm (2.1 mm x 150 mm) column with ammonium acetate buffer solution acetonitrile-water as mobile phase to constant gradient elution. Electrospray ionization source (ESI) was applied and operated in positive ion mode, and multiple reaction monitoring (MRM) mode was adopted., Results: Within concentration ranging from 0 - 1000 ng/ml the correlation coefficient for 5 compounds of 6 were greater than 0.990, recoveries were between 79% - 130%, RSD < 8.2%. The RSD of intra-day and inter-day were less than 15% (n = 6)., Conclusion: The procedure of samples collection is simple. This is a accurate and specific method for testing organophosphorus pesticides metabolites in human urine.

Objective: To establish the method to determine the presence and concentration of 8 organophosphors pesticides in serum by LC/MS/MS., Method: The serum samples were extracted by ethyl acetateether and then separated on C18 5 microm (2.1 mm x 150 mm) column with pH = 3.5 acid-ammonium acetate buffer solution, methanol--water as mobile phase to mixed gradient elution. Electro-spray ionization source (ESI) was applied and operated in positive ion mode, and multiple reaction monitoring(MRM) mode was adopted., Result: Within concentration ranging from 0-1000 ng/ml the correlation coefficient for each compound was greater than 0.990, recoveries were between 95%-129%, RSD < 7.9%. The RSD of intra-day and inter-day were less 12% (n = 6)., Conclusion: The procedure of preparing serum samples is sample and the result of this method is efficient, accurate and specific.

Objective: To establish a method of determining the presence and concentration of 16 kinds of organophosphorus pesticides in serum by GC/MS/MS., Method: The parent ions of each pesticide was detected by running GC/MS in a full scan mode, and the peak areas and the ratio of signal to noise of each product ion were compared by setting different CID voltages. The CID voltage for each parent ion was optimized and determined. Serum samples were solid-phase extracted by Oasis HLB and eluted with ethyl ether after being concentrated and made to constant volume with ethyl ether, and then were tested by GC/MS/MS., Results: The correlation coefficient for each compound in the range of 0 - 1000ng/ml was greater than 0. 990. Recoveries of standard addition were 75% - 129% ,RSD < 10%. The intra-day and inter-day RSD was less than 15% (n = 6). The limits of quantification were less than 2ng/ml except for dichlorovos (55ng/ml)., Conclusion: GC/MS/MS assay is sensitive and accurate for the determination of pesticides in serum.

Objective: To develop methods for the determination of six kinds of estrogens in cosmetics by Liquid Chromatograph-Tandem Mass Spectrometry (LC-MS/MS)., Methods: Through choosing and optimizing experimental conditions, Methanol was chosen as the extracted solvent, super sonic extraction, then centrifuging, filtrating, and the filtrate was analysed by LC-MS/MS., Results: Using this method, the LC-MS/MS response to these six estrogens was linear in the range 0-1000 ng/ml. Level limit of detection of six estrogens were 2.4, 0.2, 0.7, 12, 6 and 5 ng/g, respectively, and level limit of quantification of six estrogens were 8, 0.7, 2.4, 40, 20 and 17 ng/g, respectively, the average spiking recovery rate was 85.2%-102.8%, and relative standard deviation (RSD) was within 2.76%-8.69%. 28 cosmetics were sampled and analyzed and no estrogens were measured., Conclusions: This method possesses fairly high sensitivity and good specificity.