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71.
72.
Edyta Burda Marina Kraußer Gabriele Fischer Werner Hummel Frieder Müller‐Uri Wolfgang Kreis Harald Grger 《Advanced Synthesis \u0026amp; Catalysis》2009,351(17):2787-2790
It was found that Δ4,5‐steroid 5β‐reductases are capable of reducing also small molecules bearing an activated CC double bond such as monocyclic enones and acyclic enoate esters. As preferred Δ4,5‐steroid 5β‐reductase (5β‐StR) for this purpose, 5β‐StR from Arabidopsis thaliana was used. In part, enzyme activities are even higher than that for progesterone. Successful preliminary biotransformations with enzymatic in situ cofactor recycling were also carried out. When using the prochiral compound isophorone as a substrate, a high enantioselective reaction course (>99% ee) was observed. 相似文献
73.
Experiments were conducted on Lecane inermis feeding on filamentous bacteria and living in activated sludge to determine if the rotifers can control the growth of the bacteria responsible for bulking. The experiments showed that Lecane are capable of significantly reducing the density of Microthrix parvicella filaments. The rotifers not only survived the transfer from the culture to the activated sludge, but they multiplied quickly when foraging on filamentous bacteria. By reducing the number of filaments, the rotifers improved settling properties of the sludge. This is apparently the first report on the possibility of using rotifers to control bulking. 相似文献
74.
75.
Abstract Color changes of potato, carrot and pumpkin during air drying were the subject of this study. Air convective drying was done at 70°C and 1.5 m/s. Color of the material undergoing drying was measured with chromameter and expressed in the CIE system with chromaticity coordinates x and y, and luminance Y. It has been found that drying affects color of investigated vegetables. Luminance increased and chromaticity coordinates moved toward whiteness until a specific water content was reached. Thereafter, luminance decreased and x and y coordinates moved toward the color of the raw material. It is suggested that changes of color of drying materials were due to removal of water, substitution of water by air and deformation of surface (shrinkage). At the end of drying a concentration effect seems to predominate. Rehydrated material had a different color than that of raw one. The difference was depended on the kind of material investigated and its reconstitution properties. Nevertheless the color changes irreversibly due to the changes of surface and internal structure of the material caused by drying and rehydration processes. 相似文献
76.
M.A. Beard G.R. Tabor S.J.K. Ritchie K.E. Evans R.I. Walton 《Polymer Engineering and Science》2007,47(11):1937-1942
A novel method to study the distribution of filler particles and polymer orientation of a polymer melt within a capillary die has been developed. Material within the die is quench‐cooled and then removed to provide information about the flow regime at the instant it was frozen. The equipment has been used to examine calcium carbonate‐filled high density polyethylene under high shear. The samples were examined using Energy Dispersive X‐ray Spectrometry (EDS) as well as being studied using X‐ray Diffraction (XRD). The distribution of filler particles across the radius of the capillary has been studied at high and low wall shear rates using EDS. A constant particle distribution across the radius of the die was observed for both flow regimes. The arrangement of crystalline structures within the specimens was examined by XRD. An increase in crystalline order was noticed with increasing wall shear rate. POLYM. ENG. SCI., 47:1937–1942, 2007. © 2007 Society of Plastics Engineers 相似文献
77.
Daniels S. J. Rahat A. A. M. Tabor G. R. Fieldsend J. E. Everson R. M. 《Optimization and Engineering》2022,23(2):689-716
Optimization and Engineering - The draft tube of a hydraulic turbine plays an important role for the efficiency and power characteristics of the overall system. The shape of the draft tube affects... 相似文献
78.
Dominik Bakalarz Edyta Korbut Zhengnan Yuan Bingchen Yu Dagmara Wjcik Aleksandra Danielak Katarzyna Magierowska Slawomir Kwiecie Tomasz Brzozowski Monika Marcinkowska Binghe Wang Marcin Magierowski 《International journal of molecular sciences》2021,22(10)
Hydrogen sulfide (H2S) is an endogenously produced molecule with anti-inflammatory and cytoprotective properties. We aimed to investigate for the first time if a novel, esterase-sensitive H2S-prodrug, BW-HS-101 with the ability to release H2S in a controllable manner, prevents gastric mucosa against acetylsalicylic acid-induced gastropathy on microscopic and molecular levels. Wistar rats were pretreated intragastrically with vehicle, BW-HS-101 (0.5–50 μmol/kg) or its analogue without the ability to release H2S, BW-iHS-101 prior to ASA administration (125 mg/kg, intragastrically). BW-HS-101 was administered alone or in combination with nitroarginine (L-NNA, 20 mg/kg, intraperitoneally) or zinc protoporphyrin IX (10 mg/kg, intraperitoneally). Gastroprotective effects of BW-HS-101 were additionally evaluated against necrotic damage induced by intragastrical administration of 75% ethanol. Gastric mucosal damage was assessed microscopically, and gastric blood flow was determined by laser flowmetry. Gastric mucosal DNA oxidation and PGE2 concentration were assessed by ELISA. Serum and/or gastric protein concentrations of IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-10, IL-13, VEGF, GM-CSF, IFN-γ, TNF-α, and EGF were determined by a microbeads/fluorescent-based multiplex assay. Changes in gastric mucosal iNOS, HMOX-1, SOCS3, IL1-R1, IL1-R2, TNF-R2, COX-1, and COX-2 mRNA were assessed by real-time PCR. BW-HS-101 or BW-iHS-101 applied at a dose of 50 μmol/kg protected gastric mucosa against ASA-induced gastric damage and prevented a decrease in the gastric blood flow level. H2S prodrug decreased DNA oxidation, systemic and gastric mucosal inflammation with accompanied upregulation of SOCS3, and EGF and HMOX-1 expression. Pharmacological inhibition of nitric oxide (NO) synthase but not carbon monoxide (CO)/heme oxygenase (HMOX) activity by L-NNA or ZnPP, respectively, reversed the gastroprotective effect of BW-HS-101. BW-HS-101 also protected against ethanol-induced gastric injury formation. We conclude that BW-HS-101, due to its ability to release H2S in a controllable manner, prevents gastric mucosa against drugs-induced gastropathy, inflammation and DNA oxidation, and upregulate gastric microcirculation. Gastroprotective effects of this H2S prodrug involves endogenous NO but not CO activity and could be mediated by cytoprotective and anti-inflammatory SOCS3 and EGF pathways. 相似文献
79.
Puthukkolli P. Sameena Hazem M. Kalaji Krystyna uk-Goaszewska Tomasz Horaczek Edyta Sierka Jos T. Puthur 《International journal of molecular sciences》2021,22(24)
Copper (Cu) is an essential element involved in various metabolic processes in plants, but at concentrations above the threshold level, it becomes a potential stress factor. The effects of two different cytokinins, kinetin (KIN) and 6-benzylaminopurine (BAP), on chlorophyll a fluorescence parameters, stomatal responses and antioxidation mechanisms in castor (Ricinus communis L.) under Cu2+ toxicity was investigated. Ricinus communis plants were exposed to 80 and 160 μM CuSO4 added to the growth medium. Foliar spraying of 15 μM KIN and BAP was carried out on these seedlings. The application of these cytokinins enhanced the tissue water status, chlorophyll contents, stomatal opening and photosynthetic efficiency in the castor plants subjected to Cu2+ stress. The fluorescence parameters, such as Fm, Fv/Fo, Sm, photochemical and non-photochemical quantum yields, energy absorbed, energy trapped and electron transport per cross-sections, were more efficiently modulated by BAP application than KIN under Cu2+ toxicity. There was also effective alleviation of reactive oxygen species by enzymatic and non-enzymatic antioxidation systems, reducing the membrane lipid peroxidation, which brought about a relative enhancement in the membrane stability index. Of the various treatments, 80 µM CuSO4 + BAP recorded the highest increase in photosynthetic efficiency compared to other cytokinin treatments. Therefore, it can be concluded that BAP could effectively alleviate the detrimental effects of Cu2+toxicity in cotyledonary leaves of R. communis by effectively modulating stomatal responses and antioxidation mechanisms, thereby enhancing the photosynthetic apparatus’ functioning. 相似文献
80.
Edyta Stochmal Magdalena Hasik Anna Adamczyk Andrzej Bernasik Wincenty Turek Agnieszka Sniechota 《应用聚合物科学杂志》2008,108(1):447-455
In this work, polyaniline (PANI)–rhodium composites have been obtained for the first time. Their preparation procedure has involved reduction of Rh3+ ions in RhCl3 aqueous solutions with NaBH4 in the presence of PANI. Using UV–vis spectroscopy, it has been found that the reduction process is fast. X‐ray diffraction and Rh3d XPS studies have confirmed that metallic rhodium is incorporated into PANI matrix. SEM and TEM investigations allowed to establish that the sizes of Rh crystallites formed depend on the amount of metal in the composite as well as on the preparation conditions. It has been demonstrated that the composites containing Rh nanoparticles whose size is predominantly below 10 nm can be obtained. IR spectroscopy has proved that PANI chain is protonated in the Rh3+ reduction process. Catalytic properties of PANI–Rh composites have been investigated using isopropyl alcohol conversion as the test reaction. It has been found that the composites containing Rh nanoparticles show high redox activity. Catalytic activity of the composites in which larger, agglomerated metal particles have been present is about three times lower. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 相似文献