Production and Characterization of Sterigmatocystin

Fourteen strains of Aspergillus versicolor and 2 strains of A. nidulans were screened for sterigmatocystin (ST) production on a semi-synthetic solid substrate by high performence liquid chromatography (HPLC) analysis. Two strains of A. versicolor producing ST at 550.5 mg.kg-1 substrate and 1160.8 mg·kg-1 substrate were selected to inoculate 4 kg solid ST-producing media. After 30 days stationary incubation at 28 ℃ in the dark, 2271.6 mg of pale-yellow needle-shaped crystals were isolated and purified from the culture with a procedure applying column chromatography and recrystallization method. The crystal was proved to be sterigmatocystin by spectroanalysis and some physico-chemical analysis. The purity of the final material obtained were more than 99.9% as shown by HPLC and TLC detection. With this procedure, ST was obtained at about one tenth of its commercial cost

Variance Analysis of Growth Characteristics and Partial Production and Quality Characters of Different Tobacco Varieties

Objective] This study was conducted to discuss growth characteristics and partial production and quality characters of different varieties, so as to provide can-didates for tobacco production as wel as a theoretical basis for variety deployment in Guizhou. [Method] ‘K326’ was used as control, the experiment for variance analysis of growth characteristics and partial production and quality characters of dif-ferent tobacco varieties was carried out in Fengsan Town, Kaiyang County, Guizhou Province in 2015. [Result] GY8 grew faster in early stages and slower in late stages, the growth periods of GY2 （130 d） and GY5（129 d） were the longest, while those of Yun85 （121 d） and Yun87 （121 d） were the shortest; and GY2, GY5 and GY8 had larger plant heights, maximum leaf widths and maximum leaf areas, and Yun85, Yun87 and K326 showed larger stem girths and maximum leaf lengths. Yun87 exhibited lower natural incidences of diseases, while Yun85 and GY8 showed higher incidences of diseases. GY2, GY5 and GY8 had higher nicotine, total nitro-gen, K and Cl contents, while Yun85, Yun87 and K326 had higher total sugar and reducing sugar contents and higher total sugar/nicotine ratio. Yun85 and Yun87 showed better economic characters, while GY5 and GY8 showed poorer economic characters. [Conclusion] Yun85 and Yun87 have quality characters better than GY2 and GY8, field natural incidences of diseases lower than GY2 and GY8, and better economic characters, and thus could serve as candidates in future flue-cured tobac-co production in Guizhou.

ON HYPERSTABILITY OF THE BIADDITIVE FUNCTIONAL EQUATION

We present results on approximate solutions to the biadditive equationf（x＋y,z-w）＋f（x-y,z＋w）=2f（x,z）-2f（y,w）on a restricted domain. The proof is based on a quite recent fixed point theorem in some function spaces. Our main results state that, under some weak natural assumptions, functions satisfying the equation approximately （in some sense） must be actually solutions to it. In this way we obtain inequalities characterizing biadditive mappings and inner product spaces. Our outcomes are connected with the well known issues of Ulam stability and hyperstability.

Design Features and Performance Data of a New 400 kW Biomass Gasification Power Plant of Downdraft Type

A new biomass-gasification power plant, of medium-size downdraft type, is presented and discussed in its design features and performance characteristics. Its configuration and overall dimensions, initially conceived for 800 kW, were recently re-tuned, from a functional point of view and on the base of a parallel theoretical analysis, by decreasing to about 400 kW the former nominal power level. This provision, jointly with the basic design choice of adopting a long and amply dimensioned inlet-biomass thermal pretreatment section, turned out quite effective in achieving high gasification temperatures and a low-tar content in the produced gas at fuel-to-air ratios well below the usually imposed ones, to the advantage of the heat value of the product-gas. The paper discusses the numerical analysis results which helped to properly re-adjust the operational parameters of the gasifier and then presents the experimental performance data of the overall power plant including biomass consumption, gasification temperatures, gas production, composition and pollutants content, cold-gas conversion efficiency and global electric efficiency. Special care is devoted to investigating the issue of a significant production of carbon-containing particulate matter in the product gas, which turns out made up of char and fixed carbon much more than of tar species.