两种头孢菌素对大肠杆菌生长代谢作用的微量热研究

用微量量热法测定了37℃时头孢拉定和头孢他定对大肠杆菌DH5α代谢作用的产热曲线。根据产热曲线,分别得到了大肠杆菌DH5α在不同浓度的头孢拉定和头孢他定作用下的生长速率常数k、抑制率I、最大产热功率Pm以及最大产热功率所对应的时间tm等热动力学参数,从热动力学的角度探讨了头孢拉定和头孢他定对大肠杆菌DH5α代谢作用的影响。实验证明,头孢他定对大肠杆菌的抑制作用比头孢拉定更强

Measurement of integrated luminosity of data collected at 3.773 GeV by BESIII from 2021 to 2024

We present a measurement of the integrated luminosity e+e- of collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm = 3.773 GeV. The integrated luminosities of the datasets taken from December 2021 to June 2022, from November 2022 to June 2023, and from October 2023 to February 2024 were determined to be 4.995±0.019 fb-1, 8.157±0.031 fb-1, and 4.191±0.016 fb-1, respectively, by analyzing large angle Bhabha scattering events. The uncertainties are dominated by systematic effects, and the statistical uncertainties are negligible. Our results provide essential input for future analyses and precision measurements

Determination of the number of ψ(3686) events taken at BESIII

The number of ψ(3686) events collected by the BESIII detector during the 2021 run period is determined to be (2259.3±11.1)×106 by counting inclusive ψ(3686) hadronic events. The uncertainty is systematic and the statistical uncertainty is negligible. Meanwhile, the numbers of ψ(3686) events collected during the 2009 and 2012 run periods are updated to be (107.7±0.6)×106 and (345.4±2.6)×106, respectively. Both numbers are consistent with the previous measurements within one standard deviation. The total number of ψ(3686) events in the three data samples is (2712.4±14.3)×10^