Neutron Irradiation Effects on Boron Nitride-Based Ceramics for Use in X-ray Detection.

X-ray detectors based on conventional semiconductors with large atomic numbers are suffering from the poor stability under a high dose rate of ionizing irradiation. In this work, we demonstrate that a wide band gap ceramic-boron nitride with small atomic numbers could be used for sensitive X-ray detection. Boron nitride samples showed excellent resistance to ionizing radiation, which have been systematically studied with the neutron- and electron-aging experiments. Then, we fully analyzed the influence of these aging effects on the fundamental properties of boron nitride. Interestingly, we found that the boron nitride samples could maintain relatively good charge transport properties even after large dose of neutron irradiation. The fabricated X-ray detectors showed decent performance metrics, and the neutron-aged boron nitride even showed improved operational stability under continuous X-ray irradiation, suggesting the great potential for real applications.

Cysteine supplementation enhanced inhibitor tolerance of Zymomonas mobilis for economic lignocellulosic bioethanol production.

Inhibitors in lignocellulosic hydrolysates are toxic to Zymomonas mobilis and reduce its bioethanol production. This study revealed cysteine supplementation enhanced furfural tolerance in Z. mobilis with a 2-fold biomass increase. Transcriptomic study illustrated that cysteine biosynthesis pathway was down-regulated while cysteine catabolism was up-regulated with cysteine supplementation. Mutants for genes involved in cysteine metabolism were constructed, and metabolites in cysteine metabolic pathway including methionine, glutathione, NaHS, glutamate, and pyruvate were supplemented into media. Cysteine supplementation boosted glutathione synthesis or H2S release effectively in Z. mobilis leading to the reduced accumulation of reactive oxygen species (ROS) induced by furfural, while pyruvate and glutamate produced in the H2S generation pathway promoted cell growth by serving as the carbon or nitrogen source. Finally, cysteine supplementation was confirmed to enhance Z. mobilis tolerance against ethanol, acetate, and corncob hydrolysate with an enhanced ethanol productivity from 0.38 to 0.55 g-1∙L-1∙h-1.

Antitumor and antimetastatic activities of chloroform extract of medicinal mushroom Cordyceps taii in mouse models.

BACKGROUND: Cordyceps taii, an entomogenous fungus native to south China, is a folk medicine with varieties of pharmacological activities including anticancer effect. To validate the ethnopharmacological claim against cancer, the antitumor and antimetastatic activities of chloroform extract of C. taii (CFCT) were investigated in vivo. METHODS: The in vitro cytotoxic activities of CFCT against human lung cancer (A549) and gastric cancer (SGC-7901) cells were evaluated using the Sulforhodamine B (SRB) assay. In vivo anti tumor and antimetastatic activities, Kunming mice bearing sarcoma 180 and C57BL/6 mice bearing melanoma B16F10 were employed, respectively. The antitumor effects of CFCT were completely evaluated on the basis of the tumor weight, survival time, histologic analysis, and immune organ indices. The histopathological change, metastatic foci and malignant melanoma specific marker HMB45 in the lung tissue were detected for the evaluation of the antimetastatic activity of CFCT. RESULTS: CFCT exhibited dose- and time-dependent cytotoxicities against A549 and SGC-7901 cells with the IC50 values of 30.2 and 65.7 µg/mL, respectively. Furthermore, CFCT at a dose of 50 or 100 mg/kg could significantly inhibit the tumor growth in vivo and prolonged the survival time in two different models as compared with the model group, especially when combined with the CTX at a low dose rate. And it also increased spleen index of Kunming mice and thymus index of C57BL/6 mice. Meanwhile, histologic analysis illustrated that CFCT alone or in combination with CTX could induce tumor tissue necrosis of both models. In addition, CFCT at a dose of 50 or 100 mg/kg inhibited the lung metastasis of melanoma B16F10 in tumor-bearing C57BL/6 mice. The antimetastatic effect was also observed when CFCT was used in combination with CTX. In comparison to any other groups, CFCT at a dose of 100 mg/kg could effectively enhance the GSH-Px activities of various tissues in tumor-bearing C57BL/6 mice. CONCLUSIONS: These findings demonstrate that CFCT has potent in vivo antitumor and antimetastatic activities, and may be helpful to the development of anticancer chemopreventive agents from C. taii.