ND S .Q . S U N. 1998. Spore germination of Bacillus stearothermophilus was progressively inhibited as the concentrations of sodium bicarbonate (NaHCO 3 ) in the germination media increased from 0% to 1·0% (w/v). The inhibitory effect of NaHCO 3 was attributed to the release of HCO − 3 and its alkaline properties, each of which played a different role. At low concentrations (³ 0·3%), the inhibitory effect of NaHCO 3 was mainly due to bicarbonate. As NaHCO 3 increased from 0·3% to higher concentrations, the effect of HCO − 3 reached a plateau while the alkalinating effect became the more dominant inhibitory factor. Fourier transform infrared (FTIR) analysis reveals that sodium bicarbonate reacted with the carboxyl group (1570 cm −1 ) of some acidic amino-acid residues of protein in the spore, leading to a less orientated structure. A shift of two units towards the longer frequency for carboxyl groups indicates that a stronger interaction was formed between the carboxyl group and the Na ¦ ion. The largest ratio of peak height between the absorbance of carboxylate (1570 cm −1 ) and of amide II (1546 cm −1 ) of spores after pretreatment with 0·3% sodium bicarbonate reflects the biggest structural alterations of keratin-like proteins in the spore. The role of NaHCO 3 in enhancing the sporicidal effect of glutaraldehyde is discussed.

Charge density wave (CDW) instability is often found in phase diagrams of superconductors such as cuprates and certain transition-metal dichalcogenides. This proximity to superconductivity triggers the question on whether CDW instability is responsible for the pairing of electrons in these superconductors. However, this issue remains unclear and new systems are desired to provide a better picture. Here, we report the temperature–pressure phase diagram of a recently discovered BiS2 superconductor La2O2Bi3AgS6, which shows a possible CDW transition at T* ∼ 155 K and a superconducting transition at T c ∼ 1.0 K at ambient pressure, via electrical resistivity measurements. Upon applying pressure, T* decreases linearly and extrapolates to 0 K at 3.9 GPa. Meanwhile, T c is enhanced and reaches maximum value of 4.1 K at 3.1 GPa, forming a superconducting dome in the temperature–pressure phase diagram.