The Experts below are selected from a list of 222750 Experts worldwide ranked by ideXlab platform
Hansulrich Humpf - One of the best experts on this subject based on the ideXlab platform.
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Large Scale Production of selected type a trichothecenes the use of ht 2 toxin and t 2 triol as precursors for the synthesis of d 3 t 2 and d 3 ht 2 toxin
Mycotoxin Research, 2009Co-Authors: Marita Beyer, Ines Ferse, Hansulrich HumpfAbstract:The type A trichothecenes T-2 and HT-2 toxins are toxic secondary metabolites produced by fungi of the Fusarium genus. Their occurrence in cereals, especially in oats, implies health risks for the consumer. Therefore, it is an important task to develop selective and sensitive methods for the analysis of T-2 and HT-2 toxins, and to undertake further studies on their stability and toxicity. Although most toxins are commercially available, their high prices are the limiting factor on the realization of these experiments. Thus, we developed a method for Large-Scale Production of T-2 and HT-2 toxin as well as T-2 triol and T-2 tetraol. T-2 toxin was obtained in gram quantities by biosynthetic Production with cultures of F. sporotrichioides. As HT-2 toxin was only formed as a by-product, and T-2 triol and T-2 tetraol were not generated, these compounds were produced by alkaline hydrolysis of T-2 toxin. Separation and isolation of crude toxins was achieved by fast centrifugal partition chromatography (FCPC), which is an efficient tool for the Large-Scale purification of natural products. Using this fast and yield effective technique, several hundred milligrams of HT-2 toxin, T-2 triol, and T-2 tetraol were obtained. Subsequent, HT-2 toxin and T-2 triol were used for the Large-Scale synthesis of isotope-labeled T-2 and HT-2 toxin, respectively. Using these standards, an isotope dilution-(ID)-HPLC-MS/MS method for the quantification of T-2 and HT-2 toxin in different matrices was developed.
Marita Beyer - One of the best experts on this subject based on the ideXlab platform.
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Large Scale Production of selected type a trichothecenes the use of ht 2 toxin and t 2 triol as precursors for the synthesis of d 3 t 2 and d 3 ht 2 toxin
Mycotoxin Research, 2009Co-Authors: Marita Beyer, Ines Ferse, Hansulrich HumpfAbstract:The type A trichothecenes T-2 and HT-2 toxins are toxic secondary metabolites produced by fungi of the Fusarium genus. Their occurrence in cereals, especially in oats, implies health risks for the consumer. Therefore, it is an important task to develop selective and sensitive methods for the analysis of T-2 and HT-2 toxins, and to undertake further studies on their stability and toxicity. Although most toxins are commercially available, their high prices are the limiting factor on the realization of these experiments. Thus, we developed a method for Large-Scale Production of T-2 and HT-2 toxin as well as T-2 triol and T-2 tetraol. T-2 toxin was obtained in gram quantities by biosynthetic Production with cultures of F. sporotrichioides. As HT-2 toxin was only formed as a by-product, and T-2 triol and T-2 tetraol were not generated, these compounds were produced by alkaline hydrolysis of T-2 toxin. Separation and isolation of crude toxins was achieved by fast centrifugal partition chromatography (FCPC), which is an efficient tool for the Large-Scale purification of natural products. Using this fast and yield effective technique, several hundred milligrams of HT-2 toxin, T-2 triol, and T-2 tetraol were obtained. Subsequent, HT-2 toxin and T-2 triol were used for the Large-Scale synthesis of isotope-labeled T-2 and HT-2 toxin, respectively. Using these standards, an isotope dilution-(ID)-HPLC-MS/MS method for the quantification of T-2 and HT-2 toxin in different matrices was developed.
J E Fischer - One of the best experts on this subject based on the ideXlab platform.
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Large-Scale Production of single-walled carbon nanotubes by the electric-arc technique
Nature, 1997Co-Authors: Charles Journet, Marc Lamy De La Chapelle, P Bernier, Serge Lefrant, Andremichel Loiseau, Wolfgang K Maser, Philippe Deniard, R Lee, J E FischerAbstract:Single-walled carbon nanotubes (SWNTs) offer the prospect of both new fundamental science and useful (nano)technological applications. High yields (70-90%) of SWNTs close-packed in bundles can be produced by laser ablation of carbon targets. The electric-arc technique used to generate fullerenes and multi-walled nanotubes is cheaper and easier to implement, but previously has led to only low yields of SWNTs. Here we show that this technique can generate Large quanitites of SWNTs with similar characterisitcs to those obtained by laser ablation. this suggests that the (still unknown) growth mechanism for SWNTs must be independent of the details of the technique used to make them. The ready availability of Large amounts of SWNTs, meanwhile, should make them much more accessible for further study.
Gunter Burg - One of the best experts on this subject based on the ideXlab platform.
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bioreactor microcarrier cell culture system bio mccs for Large Scale Production of autologous melanocytes
Cell Transplantation, 2004Co-Authors: Jin Yu Liu, Jurg Hafner, Galya Dragieva, Gunter BurgAbstract:Restoration of cutaneous pigmentation can be achieved in stable vitiligo by autologous cultured melanocyte transplantation. It was the goal of this study to construct a bioreactor microcarrier cell culture system (Bio-MCCS) to produce autologous melanocytes in Large Scale. In this Bio-MCCS, porcine gelatin microbeads were used as microcarriers, spinning bottle as fermented tank. Autologous melanocytes were able to attach to and proliferate on the gelatin microbeads in serum-free melanocyte medium in the Bio-MCCS, reaching up to 24-fold the cells seeded on day 15 (MTT assay). These autologous melanocytes cultured on gelatin microbeads could leave the microbeads and proliferate on the bottom of tissue culture flasks. Although Pluronic F68 has been widely used to protect animal cells from hydrodynamic stress in animal cell bioreactors, Pluronic F68 at a concentration of 0.25-1.0% showed no significant protective effects on the autologous melanocytes cultured on the microbeads and subjected to mechanical stress in the Bio-MCCS. This Bio-MCCS using porcine gelatin microbeads as microcarriers enabled Large-Scale Production of autologous melanocytes, offering a potential treatment for Large-area stable vitiligo by direct administration of the melanocytes cultured on the gelatin microbeads to the vitiliginous site.
Ines Ferse - One of the best experts on this subject based on the ideXlab platform.
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Large Scale Production of selected type a trichothecenes the use of ht 2 toxin and t 2 triol as precursors for the synthesis of d 3 t 2 and d 3 ht 2 toxin
Mycotoxin Research, 2009Co-Authors: Marita Beyer, Ines Ferse, Hansulrich HumpfAbstract:The type A trichothecenes T-2 and HT-2 toxins are toxic secondary metabolites produced by fungi of the Fusarium genus. Their occurrence in cereals, especially in oats, implies health risks for the consumer. Therefore, it is an important task to develop selective and sensitive methods for the analysis of T-2 and HT-2 toxins, and to undertake further studies on their stability and toxicity. Although most toxins are commercially available, their high prices are the limiting factor on the realization of these experiments. Thus, we developed a method for Large-Scale Production of T-2 and HT-2 toxin as well as T-2 triol and T-2 tetraol. T-2 toxin was obtained in gram quantities by biosynthetic Production with cultures of F. sporotrichioides. As HT-2 toxin was only formed as a by-product, and T-2 triol and T-2 tetraol were not generated, these compounds were produced by alkaline hydrolysis of T-2 toxin. Separation and isolation of crude toxins was achieved by fast centrifugal partition chromatography (FCPC), which is an efficient tool for the Large-Scale purification of natural products. Using this fast and yield effective technique, several hundred milligrams of HT-2 toxin, T-2 triol, and T-2 tetraol were obtained. Subsequent, HT-2 toxin and T-2 triol were used for the Large-Scale synthesis of isotope-labeled T-2 and HT-2 toxin, respectively. Using these standards, an isotope dilution-(ID)-HPLC-MS/MS method for the quantification of T-2 and HT-2 toxin in different matrices was developed.
