In this study,a fluorescent(FL)aptasensor was developed for on-site detection of live Salmonella typhimurium(S.T.)and Vibrio parahaemolyticus(V.P.).Complementary DNA(cDNA)of aptamer(Apt)-functionalized multicolor polyhedral oligomeric silsesquioxane-perovskite quantum dots(cDNA-POSS-PQDs)were used as encoded probes and combined with dual-stirring-bar-assisted signal amplification for pathogen quantification.In this system,bar 1 was labeled with the S.T.and V.P.Apts,and then bar 2 was functionalized with cDNA-POSS-PQDs.When S.T.and V.P.were introduced,pathogen-Apt complexes would form and be released into the supernatant from bar 1.Under agitation,the two complexes reached bar 2 and subsequently reacted with cDNA-POSS-PQDs,which were immobilized on MXene.Then,the encoded probes would be detached from bar 2 to generate FL signals in the supernatant.Notably,the pathogens can resume their free state and initiate next cycle.They swim between the two bars,and the FL signals can be gradually enhanced to maximum after several cycles.The FL signals from released encoded probes can be used to detect the analytes.In particular,live pathogens can be distinguished from dead ones by using an assay.The detection limits and linear range for S.T.and V.P.were 30 and 10 CFU/mL and 102-106 CFU/mL,respectively.Therefore,this assay has broad application potential for simultaneous on-site detection of various live pathogenic bacteria in water.

OBJECTIVE: To investigate the body sweat,urine excretion and water intake of iron and steel production workers working under high temperature.METHODS: Two hundred and twenty-six workers working under high-temperature were selected as high-temperature group and 39 non-high-temperature workers as control group from an iron and steel production enterprise of Tangshan City by cluster sampling method.The workers working under high-temperature were divided into 4 subgroups(moderate physical labor 30-34 ℃ subgroup Ⅰ,heavy physical labor 30-34 ℃ subgroup Ⅱ,35-39 ℃subgroup and 40-43 ℃ subgroup) according to the labor intensity and the exposure temperature.The wet bulb globe temperature(WBGT) index in workplace was determined.The water intake survey was carried out.Water loss was estimated by body mass difference.The unit of body mass difference before and after work was conversed from kg into mL with formula“1 kg = 1 000 mL”.RESULTS: The water intake was 1 200-4 102(2 456 ± 612) mL in workers working under high-temperature,the drinking amount accounting for 74.5%-80.0% in the total water intake which were 2 004-5 749(3 810 ±672) mL.The difference of body mass before and after work was 1 513-4 932(3 078 ± 662) mL in the hightemperature operation group.The sweat excretion accounted for 86.5% of the total water excretion.In moderate physical labor 30-34 ℃ subgroup I,the total water intake,the body mass difference before and after work,the sweat and the total fluid excretion were higher and the urine excretion was lower than those of control group(P<0.05).The total water intake,the body mass difference before and after work,the sweat and the total fluid excretion in body of heavy physical labor 30-34 ℃ subgroup Ⅱ were higher than those of moderate physical labor 30-34 ℃ subgroup Ⅰ(P<0.05).With the increase of WBGT index,the total water intake,the body mass difference before and after work,the sweat and the total fluid excretion in body of 3 heavy physical labor subgroups increased and their urine excretion decreased which showed a dose-effect relationship(P<0.05).The D-value between the water intake and the sweat excretion of high-temperature operation group workers were-769--322 mL,those between the total water intake and losses were-598--96 mL.CONCLUSION: The fluid intake and excretion in workers working under high-temperature in iron and steel plant are in a negative balance.The water intake is lower than the recommended drinking amount under high-temperature environment.Sweating is the main way of water loss under high-temperature working condition.