[en] The development of liquid scintillation counting and related academic activities in China is described. It also gives the achievements in instruments and devices, methods of measurement and sample preperation, activity determination and standardization. Examples on applications of liquid scintillation techniques to various areas are given as well

[en] Two models of a low-level liquid scintillation counter, the DYS-1 and DYS-2, were designed and manufactured in our laboratory. The DYS-1 is more sensitive than the DYS-2. For the 5 ml sup(14)C benzene samples, an efficiency of 80 percent and a background of 0.54 cpm are obtained from DYS-1; its figure of merit, (Esup(2)/B), exceeds 10,000. The detection limit for tritium in water (50 ml water and 50 ml Instagel scintillator) is approximately 1 Bq/l water (t=30 min, P=68.3 percent). The sensitivity of DYS-2 is better than conventional liquid scintillation counters; for 5 ml sup(14)C benzene samples, the efficiency of the DYS-2 is above 70 percent and its Esup(2)/B varies from 1700 to 2500 depending on the construction of material of the counting vial. When a 10 ml sample of water is mixed with 10 ml of Instagel, a detection limit better than 4 Bq/l water (t=30 min, P=68.3 percent) can be attained. The DYS-1 is a single sample manual liquid scintillation counter which can be used to measure samples in various sizes between 2-100 ml with optimum geometry. The DYS-2 provides an automatic sample-changing system with a capacity of 10 vials and can be used to measure 5-20 ml samples under optimum conditions. Both instruments permit present counting time and print raw data automatically

[en] F F₁-ATPase within chromatophore was constructed as a biosensor (immuno-rotary biosensor) for the purpose of capturing single virus. Capture of virus was based on antibody-antigen reaction. The detection of virus based on proton flux change driven by ATP-synthesis of F F₁-ATPase, which was indicated by F1300, was directly observed by a fluorescence microscope. The results demonstrate that the biosensor loading of virus particles has remarkable signal-to-noise ratio (3.8:1) compared to its control at single molecular level, and will be convenient, quick, and even super-sensitive for detecting virus particles

[en] In order to observe mechanically driven proton flux in F F₁-ATPase coupled with artificial driven rotation on F₁ simultaneously, a double channel observation system was established. An artificial δ-free F F₁-ATPase was constructed with α₃, β₃, ε, γ, and c _n subunits as rotator and a, b₂ as stator. The chromatophore was immobilized on the glass surface through biotin-streptavidin-biotin system, and the magnetic bead was attached to the β subunit of δ-free F F₁-ATPase. The mechanically driven proton flux was indicated by the fluorescence intensity change of fluorescein reference standard (F1300) and recorded by a cooled digital CCD camera. The mechanochemical coupling stoichiometry between F and F₁ is about 4.15 ± 0.2H⁺/rev when the magnetic field rotated at 0.33 Hz (rps)

[en] A Nanodevice was constructed by δ-free F_oF₁-ATPase within chromatophores and actin filaments through biotinlipid-streptavidin-biotin-(AC₅)₂Sulfo-OSu system. One actin filament linking with many chromatophores functions as the Nanodevice body and many δ-free F_oF₁-ATPase as the Nanodevice motors. Movement of the Nanodevice was observed directly by fluorescence microscopy with CCD camera after illumination. The moving speed was about 2.17-24.43 μm/s for various length Nanodevices and most of them were stopped by adding CCCP. This means that the Nanodevice was driven by PMF (proton-motive force) in the cooperating δ-free F_oF₁-ATPase. From bioengineering point of view, the cooperation of F_oF₁-ATPase is a very important research field in the future