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Abstract Gram-negative ( G-) bacteria, such as denitrifying bacteria and anaerobic ammonia oxidation bacteria, are highly social organisms capable of sophisticated cooperative behavior mediated via quorum sensing. As signal molecules of the chemical communication, N-acyl-homoserine lactones ( AHLs ) can mediate the quorum sensing of the functional microbial population and regulate the population density. To understand the growth of functional microbial population and the mechanism for biological nitrogen removal in upflow microaerobic sludge reactors ( UMSRs ) treating organic wastewater with low ratio of chemical oxygen demand to total nitrogen, a method was established to simultaneously detect AHLs in the microaerobic processes. Water-sludge mixtures sampled from the UMSRs were pretreated in sequence by liquid-liquid extraction using ethyl acetate, rotary evaporation, constant volume with methanol, separation by C18 column. Gradient elution was carried out using 5 mmol/L ammonium acetate ( containing 0 . 1% formic acid ) and methanol as mobile phases. On the base of multiple reaction monitoring analysis, a triple quadrupole mass spectrometer with an electrospray ionization was introduced to detect the target compounds. Nine kinds of AHLs were used to evaluate the established method and the results showed that the detection limits were 0 . 01-0 . 5 μg/L and all of the AHLs presented excellent linearity with the concentration ranging from 0 . 5 to 100 μg/L. The recovery and relative standard deviation ranged from 62. 5% to 118. 1% and 2. 9% to 12. 1%, respectively. The analysis could be finished within 6. 5 min. The rapid, accurate and precise method for detecting AHLs provided a new insight into the growth and metabolic activity of functional microbial population in the activated sludge processes to understand the mechanism of biological nitrogen removal, suggesting a good application in regulation and operation of wastewater biological treatment processes.
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Aim To investigate the antinociception, tolerance and withdrawal abstinence of δ/μ/κ opioid receptor triple agonist KUST201 ( DPI-125 ) in rats. Methods Male Sprague-Dawley rats were used to de-termine the time course of analgesic effects and ED50 effects of co-administration of naltrindole were assessed as well. In withdrawal experiments, KUST201 was ad-ministrated twice daily for 3 d with increasing doses each day. On the 4th day, the rats were given a single dose, challenged with naloxone 3 h later, and signs of abstinence were monitored. Results The ED50 values of KUST201 were 0. 34 mg·kg-1 in tail-pinch test and 0. 68 mg · kg-1 in hot-plate test. The antinociception actions of KUST201 started to decrease 1 h after ad-ministration, and disappeared after 2 h. In chronic tol-erance experiments, the antinociception actions started to decrease on d 3 , and completely disappeared on d 7 . Naltrindole could reduce the antinociceptive action of KUST201. In withdrawal experiments, abstinence scores increased significantly in the dose range between 2~8 times of tail-pinch ED50 . Conclusion Compared with previously reported δ/μ/κ triple agonist DPI-3290 , KUST201 exhibits similar antinociceptive effects in rats. The chronic tolerance to KUST201 actions de-velops less quickly, but the abstinence scores of KUST201 are slightly higher. The activation of δ-opi-oid receptor can synergistically enhance the antinoci-ception mediated by μ-receptor.
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Objective:Through a study on knowledge, attitudes, and practice of tobacco control of medical staff in Gansu Province, the paper aims to analyze the issues of participation, community tobacco control leadership and other aspects that impact the creation of a smoke-free healthcare system in order to provide a basis for the formulation of policies to improve the health professional mechanism of tobacco control. Methods:The stratified cluster sampling method was adopted to select 34 companies, accounting for a total of 805 medical staff as the study population in all kinds of health institutions. A self-designed questionnaire was adopted to investigate their knowledge, attitudes, and practice via on-site self-administered surveys. Results:the medical staff lacks knowledge as to the depth and breadth of damage from the use of tobacco. Although their attitude towards tobacco control is positive, the comprehensive to-bacco control service capabilities are insufficient. Logistic regression analysis showed that tobacco control capabilities of medical staff is related to their attitude toward smoking and whether or not they discourage smoking or asking about smoking . Conclusion:The key to the creation of a smoke-free health system to lead the community in tobacco control is the targeted tobacco cessation knowledge and skills training of medical staff to reduce smoking rates among medical staff and enhance the awareness of administrative staff.