Monascus pigments, which are produced by various species of Monascus, often have been used as a natural colourant and as traditional natural food additives, especially in Southern China, Japan and Southeastern Asia. The limitation of wide using Monascus pigment is attributed to one of its secondary metabolites named citrinin. The aim of this study was to investigate the influence of pigment and citrinin production via submerged fermentation (SmF) and solid-state fermentation (SF) from rice (Oryza sativa L.) by Monascus purpureus AS3.531. The optimal fermentation temperature and pH were significantly different for pigment production through different fermentation mode (35 °C, pH 5.0 for SF and 32 °C, pH 5.5 for SmF, respectively). Adding 2% (w/v) of glycerol in the medium could enhance the pigment production. On the optimized condition, although the concentration of citrinin produced by SmF (19.02 ug/g) increased more than 100 times than that by SF (0.018 ug/g), the pigment yield by SmF (7.93 U/g/g) could be comparable to that by SF (6.63 U/g/g). Those indicate us that fermentation mode seems to be the primary factor which influence the citrinin yield and secondary factor for pigment production.
The sorption of radiocadmium on Ca-montmorillonite as a function of contact time, pH, ionic strength, foreign ions, humic
acid (HA) and fulvic acid (FA) was studied using batch technique. The results demonstrated that the sorption of Cd(II) was
dependent on ionic strength at pH < 9, and was independent of ionic strength at pH > 9. Outer-sphere surface complexation
and/or ion exchange were the main mechanism of Cd(II) sorption on Ca-montmorillonite at low pH, whereas the sorption at high
pH was mainly dominated via inner-sphere surface complexation. The sorption of Cd(II) on Ca-montmorillonite was dependent
on foreign ions at low pH values, but was independent of foreign ions at high pH values. A positive effect of HA/FA on Cd(II)
sorption was found at low pH values, whereas a negative effect was observed at high pH values. The thermodynamic parameters
(i.e., ΔH0, ΔS0, ΔG0) were calculated from the temperature dependent sorption isotherms, and the results indicated that the sorption process of
Cd(II) on Ca-montmorillonite was spontaneous and endothermic.
Authors:Shengyun Zhu, Yongnan Zheng, Yi Zuo, Dongmei Zhou, Daqing Yuan, Anli Li, Zhiqiang Wang, Xiao Duan, Meng Liu and Yong Li
The perturbed angular correlation (PAC) and positron annihilation spectroscopy (PAS) that use nuclear probes to characterize
the micro-structure of materials are briefly described. Three examples are given to show their partial applications. The first
example is the study of radiation damage in Si irradiated by fast neutrons of 1.45·1020 cm−2 and 178W heavy ions of 5·1011 cm−2, respectively. The PAC and PAS measurements all show that the monovacancy-oxygen complexes and divacancies and divacancy-oxygen
complexes were produced by the irradiations, and quadrivacancies and quadrivacancy-oxygen complexes were formed during thermal
annealing. The second one illustrates the investigation of high Tc superconductivity for YBaCuO. The PAS experiment found the charge transfer during the superconducting trasition. The PAC
measurement suggested a transition of two-to one-dimensional Cu-O-Cu chain structure at the superconducting trasition temperature
Tc, which favors the charge transfer from the CuO layer to the CuO chain in YBaCuO. The third one is for investigating the hydrogen
behavior in Pd0.75Ag0.25-Hx as functions of temperature from 77 K to RT and hydrogen concentration (x) from 0 to 35 at.%. The PAC and PAS results exhibit that hydrogen atoms are congregated into the hydrogen bubbles and the
hydrogen bubbles grow with the increasing of the hydrogen concentration in Pd0.75Ag0.25-Hx. These examples demonstrate that the PAC and PAS techniques are very sensitive and powerful tools in materials science, which
can well investigate phenomena in materials on atomic scale.
Authors:Jin-Song Wei, Zhe-Bin Jin, Zhi-Qiang Yin, Qiang-Min Xie, Ji-Qiang Chen, Zi-Gang Li and Hui-Fang Tang
In order to determine whether local anesthetics directly affect the propagation and strength of myometrial contractions, we compared the effects of bupivacaine, ropivacaine, lidocaine and tetracaine on the contractions of myometrium isolated from pregnant and non-pregnant rats. Full-thickness myometrial strips were obtained from 18- to 21-day pregnant and non-pregnant Sprague-Dawley rats and incubated in an organ bath. When spontaneous contractions became regular, strips were exposed to cumulative concentrations of the four local anesthetics ranging from 0.01 to 300 μmol/L and the amplitude and frequency of contraction were recorded. All four compounds caused a concentration-dependent inhibition of the contractility of pregnant and non-pregnant uterine muscle. In pregnant myometrium, the concentration that caused 50% inhibition (IC50) was 100 μmol/L for bupivacaine, 157 μmol/L for ropivacaine, > 1000 μmol/L for lidocaine, and 26.3 μmol/L for tetracaine. In non-pregnant myometrium, the IC50 was 26.9 μmol/L for bupivacaine, 40 μmol/L for ropivacaine, 384 μmol/L for lidocaine, and 7.4 μmol/L for tetracaine. These results suggested that local anesthetics do inhibit myometrial contractions in pregnant and non-pregnant rats in a concentration-dependent manner.