[Synthesis of carbendazim artificial antigens and preparation of murine polyclonal antibodies].

Objective To synthesize carbendazim artificial antigens, prepare carbendazim polyclonal antibodies and identify their characteristics. Methods Active carboxyl groups were introduced to prepare the carbendazim haptens by the mixed anhydride method. The artificial antigens and coating antigens were obtained by coupling the small molecule haptens with carriers of bovine serum albumin (BSA) and ovalbumin (OVA). Sodium dodecyl sulfate polycrylamide gel electropheresis (SDS-PAGE) was used to identify carbendazim artificial antigens. Mice were immunized with the prepared artificial antigens to obtain polyclonal antibodies against carbendazim, and the antibody titers and specificity were identified by indirect ELISA. Results Carbendazim artificial antigens were successfully prepared. The titer of polyclonal antibody was above 1:12 800 and the half-maximal inhibitory concentration ( IC50) of the antibody was 0.107 µg/mL. The cross-reactivity rates with both benomyl and thiabendazole were less than 1%. Conclusion Polyclonal antibodies with high sensitivity and high specificity were successfully prepared, laying the foundation for the establishment of a rapid detection method for carbendazim residues.

[Establishment of a rapid detection method of colloidal gold immunochromatographic competition assay for organophosphorus pesticides].

Objective To establish a colloidal gold immunochromatography and develop the corresponding test strip for detecting organophosphorus compounds including omethoate, phoxim, dipterex, and parathion in fruits, vegetables and drinking water. Methods Artificial antigen molecules of organophosphorus compounds were synthesized using N-hydroxysuccinimide esters. Acetylcholinesterase antigen was prepared and purified, and the serum containing the corresponding antibody was prepared, purified, and labeled. The working parameters of the test strip were optimized, and the performance evaluation of it was conducted. Results The titer of the antisera ranged from 1:32 to 1:64, with a protein content of approximately 2 mg/mL. The purified polyclonal antibodies displayed target bands at relative molecular masses (Mr) of 25 000 and 55 000, indicating satisfactory purity. The reaction time of the test strips was between 5 to 10 minutes, with a detection limit for samples at 200 ng/mL. Both specificity and accuracy were satisfactory, and the test strip remained valid for 6 months. Conclusion A simple and rapid colloidal gold immunochromatography is established successfully for detecting several organophosphorus compounds and may be useful for on-site preliminary screening of samples in large quantities.

Job satisfaction and turnover of the first group of rural-oriented tuition-waived medical students in Guangxi, China: a mixed-method study.

BACKGROUND: In 2010, China launched a rural-oriented tuition-waived medical education (RTME) programme to train more general practitioners (GPs) to meet the needs of the rural health workforce. Motivating and maintaining GPs is an important consideration for the shortage in the rural health workforce. This study aimed to investigate job satisfaction and turnover among the first group of rural-oriented tuition-waived medical students (RTMSs) who had completed a three-year compulsory service in Guangxi, as well as the factors affecting RTMSs turnover. METHODS: This study adopted a mixed-method approach. A quantitative survey of 129 RTMSs was analysed (81.6% response rate), and qualitative interviews were conducted with 30 stakeholders, including 18 RTMSs, six administrators of the County Health Bureau, and six administrators of township health centers (THCs). A t-test, chi-square test, Fisher's exact test, and logistic regression analysis were used to examine the quantitative data, and thematic analysis was used to analyse the qualitative data. RESULTS: Among the 129 participants, the turnover rate was high, with 103 RTMSs reporting turnover (79.84%). Interpersonal relationships scored the highest in job satisfaction (3.63 ± 0.64) among RTMSs, while working conditions were rated the lowest (2.61 ± 0.85). Marital status (odds ratio [OR] = 0.236, 95% confidence interval [95%CI] = 0.059-0.953, P = 0.043), only child status (OR = 8.660, 95%CI = 1.714-43.762, P = 0.009), and job return satisfaction (OR = 0.290, 95%CI = 0.090-0.942, P = 0.039) were significantly associated with turnover. Univariate analyses showed that income had a significant influence on turnover, but the relationship gone by multivariable; however it was deemed important in the qualitative study. Qualitative analysis revealed that turnover was influenced by the working atmosphere, effort-reward imbalance, professional competence, and opportunities for training and promotion. CONCLUSIONS: This study provides insights for the policymakers about the priority areas for retaining GPs in rural locations and provides reference values for the retention of GPs in other regions with a shortage of rural health workers. For RTMSs to continue providing services to rural areas, the government should improve their salaries, balance their income and workload, provide more opportunities for training and career promotion, and managers should recognise their efforts and create an optimistic working atmosphere.

Simultaneous photocatalytic removal of tetracycline and hexavalent chromium by BiVO4/0.6CdS photocatalyst: Insights into the performance, evaluation, calculation and mechanism.

In this study, a novel Z-scheme heterojunction on bismuth vanadium/cadmium sulfide (BiVO4/0.6CdS) was developed and evaluated for simultaneous photocatalytic removal of combined tetracycline (TC) and hexavalent chromium Cr(Ⅵ) pollution under visible light. Based on the analysis of intermediate products and theoretical calculation, the property of the intermediate products of TC degradation and the effect of built-in electric field (IEF) of composite materials on photo-generated carrier separation were illustrated. According to the experiments and evaluation results, the performance of BiVO4/0.6CdS is higher than CdS 2.83 times and 4.82 times under the visible light conditions, with the aspect of simultaneous oxidizing TC and reducing Cr(Ⅵ), respectively. The catalyst has a faster removal rate in the binary composite pollution system than the single one. Therefore, the photocatalytic degradation of TC using BiVO4/0.6CdS can reduce the toxic effect of TC on the environment. The aforementioned evaluation provides a new design strategy for Z-scheme heterojunction to simultaneous photocatalytic degradation of composite organic and inorganic pollutants.

Efficient photodegradation of antibiotics by g-C3N4 and 3D flower-like Bi2WO6 perovskite structure: Insights into the preparation, evaluation, and potential mechanism.

Antibiotics are emerging organic pollutants that have attracted huge attention owing to their abundant use and associated ecological threats. The aim of this study is to develop and use photocatalysts to degrade antibiotics, including tetracycline (TC), ciprofloxacin (CIP), and amoxicillin (AMOX). Therefore, a novel Z-scheme heterojunction composite of g-C3N4 (gCN) and 3D flower-like Bi2WO6 (BW) perovskite structure was designed and developed, namely Bi2WO6/g-C3N4 (BW/gCN), which can degrade low-concentration of antibiotics in aquatic environments under visible light. According to the Density Functional Theory (DFT) calculation and the characterization results of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FITR), Scanning electron microscopy - energy spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS), this heterojunction was formed in the recombination process. Furthermore, the results of 15 wt%-BW/gCN photocatalytic experiments showed that the photodegradation rates (Rp) of TC, CIP, and AMOX were 92.4%, 90.1% and 82.3%, respectively, with good stability in three-cycle photocatalytic experiments. Finally, the quenching experiment of free radicals showed that the holes (h+) and superoxide radicals (·O2-) play a more important role than the hydroxyl radicals (·OH) in photocatalysis. In addition, a possible antibiotic degradation pathway was hypothesized on the basis of High performance liquid chromatography (HPLC) analysis. In general, we have developed an effective catalyst for photocatalytic degradation of antibiotic pollutants and analyzed its photocatalytic degradation mechanism, which provides new ideas for follow-up research and expands its application in the field of antibiotic composite pollution prevention and control.

Antidepressant Effect and Mechanism of Picea mariana Essential Oil on ReserpineInduced Depression Model Mice.

The disturbance of brain biochemical substances serves as a primary cause and aggravating factor of depression. This study aimed to investigate the principal components of Picea mariana and its effect on reserpine-induced depression mice,w ith its relationship with brain central transmitters and related proteins. Methods: The main constituents of Picea mariana essential oil (PMEO) were analyzed by GC-MS spectrometry. The quiescent time in the tail suspension test (TST) and forced swim test (FST), along with the weight change of the mice was detected. The number of normal neurons was quantified through Nissl staining. Immunohistochemistry was employed to determine the levels of 5HT-1A and 5HT-2A in the brain. Western blotting was utilized to detect 5HT-2A, CRF and TrkB protein levels. RTqPCR was used to detect the mRNA levels of 5HT-1A, 5HT-2A, TrkB, CRF, and BDNF. The main active ingredients of PMEOs were (-) -bornyl acetate (44.95%), γ-Terpinene (14.17%), and ß-Pinene (10.12%). PMEOs effectively improved the retardation and weight loss due to anorexia in depression-like mice. This improvement was associated with an increase in the number of normal neurons. After administering different doses of PMEOs, the levels of 5HT-1A, 5HT-2A, CRF, and TrkB were found to be increased in brain tissue. RT-qPCR revealed that the mRNA levels of CRF, 5HT-1A, and 5HT-2A were generally upregulated, whereas TrkB and BDNF were downregulated. Conclusion: PMEO can effectively alleviate depression induced by reserpine, which may be attributed to its regulation of 5HT-1A, 5HT-2A, CRF and TrkB protein expression, thus reducing brain nerve injury.