We hypothesized that activation of the central histaminergic system is required for neuroprotection induced by hypoxic preconditioning. Wild-type (WT) and histidine decarboxylase knockout (HDC-KO) mice were preconditioned by 3 hours of hypoxia (8% O 2 ) and, 48 hours later, subjected to 30 minutes of middle cerebral artery (MCA) occlusion, followed by 24 hours of reperfusion. Hypoxic preconditioning improved neurologic function and decreased infarct volume in WT or HDC-KO mice treated with histamine, but not in HDC-KO or WT mice treated with a-fluoromethylhistidine (a-FMH, an inhibitor of HDC). Laser-Doppler flowmetry analysis showed that hypoxic preconditioning ameliorated cerebral blood flow (CBF) in the periphery of the MCA territory during ischemia in WT mice but not in HDC-KO mice. Histamine decreased in the cortex of WT mice after 2, 3, and 4 hours of hypoxia, and HDC activity increased after 3 hours of hypoxia. Vascular endothelial growth factor (VEGF) mRNA and protein expressions showed a greater increase after hypoxia than those in HDC-KO or a-FMH-treated WT mice. In addition, the VEGF receptor-2 antagonist SU1498 prevented the protective effect of hypoxic preconditioning in infarct volume and reversed increased peripheral CBF in WT mice. Therefore, endogenous histamine is an essential mediator of hypoxic preconditioning. It may function by enhancing hypoxia-induced VEGF expression.

Cadmium’s (Cd) impact on the photosynthetic activities of energy plant maize was investigated in pot experiments containing different Cd contaminated levels during the whole growth period. The results showed that the ability of photosynthesis was not obviously inhibited by elevated Cd stress. Net photosynthetic rate (NPR) was decreased with the growth of maize, while transpiration rate (TR), stomatal conductance (gs>) and intercellular CO2 concentration (Ci) were enhanced in heading period, then decreased in maturity period. The change of fluorescence quenching and photosystem II (PSII) efficiency was consistent with NPR. Thus, the influence of photosynthesis under Cd stress mainly depended on the response of PSII reaction centre.

In this study, the morphological responses of wheat to Cd during the whole growth stage were investigated in pot experiment with substrates containing 0, 1, 5, 10, 50 and 100 mg Cd/kg soil. The results showed that wheat was moderately tolerant to Cd stress, and the most sensitive endpoint to Cd toxicity was tiller number. The seed germination was not effected by Cd at all concentrations. The No Observed Adverse Effect Concentration (NOAEC) was 10 mg Cd/kg, and the Low Observed Adverse Effect Concentration (LOAEC) was 50 mg Cd/kg for the wheat.

The cadmium (Cd) stress to xylophyta Vitex negundo var. heterophylla including growth responses and Cd accumulation in plant was investigated in pot experiment with different Cd concentrations. The result indicated that the shoot length, shoot diameter and root diameter as well as the biomass of organs were obviously decreased when Cd was 50 mg/kg. 100 mg/kg Cd caused the chlorosis of the leaf. The accumulated ability of Cd in Vitex negundo var. heterophylla in turn was root > leaf > shoot. This plant presented efficient ability in removing the Cd from the contaminated soil when initial Cd in the soil was 20 mg/kg.

Phosphate adsorption from aqueous solution using slag was investigated as the function of pH, contact time and adsorbent dosage. The results showed that the optimum value of pH was 2. Both Langmuir isotherm and Freundlich isotherm model were fit to describe the phosphate adsorption, and the maximum adsorption capacity from Langmuir model calculated was 9.09 mg/L. The adsorption process on slag followed pseudo second-order kinetic. Due to the relatively high adsorption capacity, the slag has the potential for application to removal phosphate from wastewater.