Gold immunochromatographic sensor for the rapid detection of twenty-six sulfonamides in foods

A gold immunochromatographic sensor （GICS） was developed for the rapid detection of 26 sulfonamides in honey samples. The sensor was based on a group-specific monoclonal antibody （mAb） that can recognize all 26 sulfonamides. Three haptens （hapten I with a thiazole ring, hapten 2 with a benzene ring, and hapten 3 with a straight carbon chain） were used for antigen preparation. With hybridoma technology, a group-specific mAb was screened with a 50% maximal inhibitory concentration （IC50） against sulfathizole （STZ） and the other 25 analogues ranging from 0.08 to 90.18 ng/mL. Mono-dispersed gold nanoparticles were conjugated with the mAb to develop the lateral immunochromatographic strip. A labeled antibody concentration of 0.1 pg/mL and a coating antigen concentration of 0.2 μg/mL in the test line were chosen for strip preparation. Under optimized conditions, the visual limits of detection （vLOD） for the concentrations of STZ, sulfamethoxazole, sulfamethizole, sulfadiazine, sulfamerazine, sulfadimethoxine, sulfamonomethoxine, sulfameter, sulfamethoxypyridazine, and sulfachloropyridazine were 5, 0.25, 0.25, 10, 5, 10, 25, 2.5, 5, 0.25, and 10 μg/kg, respectively. Scanner analysis in honey samples revealed good performance for detection of the 26 sulfonamides. Commercial honey samples were tested with the sensor and positive results were confirmed with high-performance liquid chromatography. The proposed strip sensor provides a convenient method for the rapid and reliable determination of sulfonamides pollutants in honey samples.

Powertrain parameter matching and optimal design of dual-motor driven electric tractor

The rationality of powertrain parameter design has a significant influence on the traction performance and economic performance of electric tractor.At present,researches on powertrain parameter design mainly focus on electric vehicles,and electric agricultural machinery draw much less attention.Therefore,a method of powertrain parameter matching and optimization design for electric tractor was proposed in this paper,which was based on dual-motor coupling drive mode.The particle swarm optimization(PSO)algorithm based on mixed penalty function was used for parameter optimization.Parameter optimization design was programmed using MATLAB.A simulation dynamic model with optimization design variables of electric tractor powertrain was established based on MATLAB/Simulink.Compared with the simulation results before optimization,the objective functions were optimized and the traction performance of electric tractor was improved,which indicated the effectiveness of the proposed method.

Rett syndrome with atrial tachycardia in a girl

To the editor:A 26-month-old girl presented with atrial tachycardia as the main cardiac manifestation,which lasted for more than 1 year.The girl was born to healthy,non-consanguineous parents and had no family history of similar diseases.There was no asphyxia at birth and no abnormal feeding history.Her development was normal in the early stages.However,at the age of 17 months she did not respond to her name and hardly communicated with her parents.She was also unable to grasp things and repeatedly chewed on her hands.In the meantime,she frequently started grinding her teeth when awake.