Depsides and depsidones from the soil-derived fungus Aspergillus unguis PSU-RSPG204

Three new depsides, aspergisides A-C, and one new depsidone, aspergisidone, were isolated from the soil-derived fungus Aspergillus unguis PSU-RSPG204 together with one phthalide derivative and 11 depsidones including emeguisin A, aspersidone and folipastatin. The structures were determined by spectroscopic evidence. Aspersidone and emeguisin A showed remarkably antibacterial activity against Staphylococcus aureus and methicillin-resistance S. aureus with equal MIC values of 0.5?μg/mL. Emeguisin A, which displayed the highest activity with 87.06% inhibition of human colon carcinoma (HCT-116) cell viability, decreased numbers of live cells/numbers of dead cells in a dose-dependent manner with the IC₅₀ values of 34.8–84.7?μM in a 3D culture model depending on durations of incubation. In addition, folipastatin dose-dependently inhibited forskolin-stimulated chloride secretion in human intestinal epithelial (T84) cells with an IC₅₀ value of 0.5?μM. These depsidones were considered to be inactive against noncancerous Vero Cells with the IC₅₀ values of >10?μM.     

钇掺杂对磷酸亚铁锂薄膜光波导传感元件气敏特性的影响

利用水热法合成出LiFePO4和钇(Y)掺杂的LiFePO4粉体,并作为敏感试剂,用浸渍-提拉法固定在锡掺杂玻璃光波导表面,分别研制了LiFePO4和LiFe0.99 Y0.01 PO4薄膜/锡掺杂玻璃光波导传感元件.用这些薄膜传感元件对挥发性有机气体进行检测,并比较了它们的气敏特性.结果表明,掺杂Y后LiFePO4薄...     

热处理对LiFe1-0.01xY0.005xAg0.005xPO4薄膜光波导传感元件气敏性的影响

以FeSO4.7H2O,H3PO4,LiOH.H2O,AgNO3及Y(NO3)3.6H2O为原料,利用水热法一步合成出了LiFe1-0.01xY0.005xAg0.005xPO4粉体(x=0.5,1.0),并将该材料作为敏感试剂,用旋转-甩涂法做成纳米薄膜固定在锡掺杂玻璃光波导表面,在不同温度下进行热处理。采用紫外-可见分光光度计、测厚仪以及自组装的玻璃光波导气敏测试仪研究了热处理对LiFe1-0.01xY0.005xAg0.005xPO4薄膜光学及气敏特性的影响。研究结果表明:在450℃下进行热处理的薄膜元件具有良好的光学透明及较好的气敏特性。相同浓度的不同挥发性有机气体中,该传感元件对二甲苯气体有很好的选择性响应,其检测响应范围为1×10-7～1×10-3(V/V),响应-恢复时间分别小于5和100 s。     

Blennolide derivatives from the soil-derived fungus Trichoderma asperellum PSU-PSF14

Three new blennolide derivatives, blennolides L-N (1–3), together with five known metabolites were isolated from the soil-derived fungus Trichoderma asperellum PSU-PSF14. Their structures were determined by analysis of spectroscopic data. Their relative configurations were determined by analysis of NOEDIFF data and confirmed by X-ray crystallography for compound 1 whereas the absolute configurations were established by means of experimental and calculated TDDFT ECD data. Compound 1 displayed antifungal activity against Cryptococcus neoformans ATCC90112 and ATCC90113 flucytosine-resistant with the MIC values of 128 and 64?μg/mL, respectively, and was inactive against noncancerous Vero cell lines.     

Detection of Amines in Lamb Spoilage by Optical Waveguide Sensor Based on Bromophenol Blue-Silicon Composite Film

We herein report the development of a bromophenol blue(BPB)-silicone composite film/K^+-exchange glass optical waveguide(OWG)sensor for the detection of amines produced during the spoilage of lamb.the optical and structural properties of the sensitive thin film were studied by ultra violet-visible(UV-Vis)spectroscopy,and the light source of the OWG detecting system was selected.Gas sensing measurements showed that the sensor exhibited a good selectivity,higli sensitivity,and short response-recovery time towards volatile amine gases in the 0.00117一11.72 mg/g range.The as-prepared optical waveguide device was subsequently applied in the determination of gases(namely trimethylamine,dimethylamine,and ammonia)emitted from the lamb samples(5g)stored at room temperature(25℃)and in a refrigerator(5℃)for 0—4 d,and the total volatile basic nitrogen(TVB-N)contents were detected by UV-Vis spectroscopy,and the results were compared witli those obtained using our detector.It was found that the sensing element was capable of detecting mixed gases produced by the decomposition of lamb samples in a refrigerator for 0.5 h,where the TVB-N content was lower than 35μg/g.     

Cyclodextrin Polymer Films Optical Waveguide Sensor for Volatile Organic Gas Detection

A sensitive optical waveguide(OWG) sensor which can be used to detect volatile organic compounds(VOCs) was presented. The sensing device(element) was fabricated by means of the immobilization of polyvinyl pyrrolidone(PVP)-cyclodextrin(CD) composite film over a single-mode potassium ion exchanged glass OWG via spin-coating method. The sensor shows higher response to styrene gas than to other VOCs and displays a linear response to styrene gas in a range of 1-1000 μL/L.     

Characterization of the Optical and Gas Sensitivities of a Nickel-Doped Lithium Iron Phosphate Thin Film

The influence of heat-treatment temperature on the optical properties (refractive index, transmittance, and attenuation) and gas sensitivities of nickel-doped lithium iron phosphate (LiFe_0.99Ni_0.01PO₄) thin films were discussed. LiFe_0.99Ni_0.01PO₄ was synthesized in one step using hydrothermal methods and fixed to tin-diffused glass as a sensing film by spin-coating before calcination at different temperatures. The obtained thin films were characterized by refractive index, thickness, attenuation, and porosity, as well as gas sensing performances for benzene, toluene, and xylene. The experimental results indicated that the LiFe_0.99Ni_0.01PO₄ thin films dried at 450°C displayed higher refractive indices, good transparency, and less attenuation; thus, the resulting sensor of a LiFe_0.99Ni_0.01PO₄ thin film/tin-diffused optical wave-guide exhibited a greater response to xylene in the concentration range of 0.1–1000?ppm.