This study investigated the enrichment of cancer stem cells (CSCs) in hepatocellular carcinoma (HCC) by chemotherapy. SMMC-7721 cells were inoculated into mice treated with 0, 2, 5 or 10 mg/kg cyclophosphamide (CTX). Tissue from the resulting tumours was re-inoculated into CTX-treated mice two more times, thus producing three generations of tumour cells for each dose of CTX. Chromosome and fluorescence-activated cell sorting analyses were performed to determine the purity of the enriched cells. Sphere culture, colony formation and proliferation assays demonstrated that the self-renewal potential, proliferative activity and clonogenicity of the enriched cells in vitro increased with increasing chemotherapy dose and generation. The ability of the enriched cells to produce xenograft tumours in mice was also dependent on chemotherapy dose and generation. In conclusion, subjecting HCC cells to chemotherapy in vivo enriched the samples for HCC CSCs in a dose- and generation-dependent manner.

The synthesis of the trifluoromethanesulfonate salt of the pentaarnmine (dimethy1 sulfide)-cobalt(III) ion, [NH3)5Co-S(CH3)2]3+, is described along with the kinetics of its hydrolysis in basic and acidic solutions. The synthesis proceeds in 44% yield from the reaction of [(NH3)5Co-OSO2CF3] (CF3SO3)2 with CH3SCH3 in tetramethylene sulfone at 80�C. The salt has been characterized by elemental analysis, visible-U.V. spectroscopy, and 1H n.m.r. In basic solution the complex decomposes by Co-S cleavage to yield [(NH3)5CO-OH]2+ and non-coordinated CH3SCH3. The kinetics of this reaction were studied in phosphate buffers ranging from pH 8.50 to 11.67 ( �= 1.0 M); a linear dependence of the reaction rate on [OH-] was observed. At 25�C, kOH = 8.8 � 0.2 dm3 mol-1 s-1. Activation parameters, determined over a temperature range from 15 to 44�C, were ΔH‡ = 152 � 3 kJ mol-1 and Δ S‡ = 286 � 9 J K-1 mol-1. In 0.01 M HClO4 ( � = 1.0 M, 25�C), the cobaltsulfur bond is cleaved at a rate of 1.6×10-6 s-l. Activation parameters, determined over a temperature range from 25 to 60�C, were ΔH‡ = 106 � 5 kJ mol-1 and ΔS‡= -2 � 16 J K-1 mol-1.

The total and differential cross sections of the process e + e − → nγ with n ≥ 2 are measured using data collected by the L3 experiment at centre-of-mass energies of √ s = 183 and 189 GeV. The results are in agreement with the Standard Model expectations. Limits are set on deviations from QED, contact interaction cut-off parameters and masses of excited electrons.

The BEPCII Luminosity Monitor (BLM) monitors relative luminosity per bunch. The counting rates of gamma photons, which are proportional to the luminosities from the BLM at the center of mass system energy of the ψ (3770) resonance, are obtained with a statistical error of 0.01% and a systematic error of 4.1%. Absolute luminosities are also determined by the BESIII End-cap Electro-Magnetic Calorimeter (EEMC) using Bhabha events with a statistical error of 2.3% and a systematic error of 3.5%. The calibration constant between the luminosities obtained with the EEMC and the counting rates of the BLM are found to be 0.84±0.03 (×1026 cm−2·count−1). With the calibration constant, the counting rates of the BLM can be scaled up to absolute luminosities.