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211.
Leite RS Bocchini DA Martins Eda S Silva D Gomes E Da Silva R 《Applied biochemistry and biotechnology》2007,137(1-12):281-288
This article investigates a strain of the yeast Aureobasidium pullulans for cellulase and hemicellulase production in solid state fermentation. Among the substrates analyzed, the wheat bran culture presented the highest enzymatic production (1.05 U/mL endoglucanase, 1.3 U/mL beta-glucosidase, and 5.0 U/mL xylanase). Avicelase activity was not detected. The optimum pH and temperature for xylanase, endoglucanase and beta-glucosidase were 5.0 and 50, 4.5 and 60, 4.0 and 75 degrees C, respectively. These enzymes remained stable between a wide range of pH. The beta-glucosidase was the most thermostable enzyme, remaining 100% active when incubated at 75 degrees C for 1 h. 相似文献
212.
We study the behavior of thin elastic sheets that are bent and strained under a weak, smooth confinement. We show that the emerging shapes exhibit the coexistence of two types of domains. A focused-stress patch is subject to a geometric, piecewise-inextensibility constraint, whereas a diffuse-stress region is characterized by a mechanical constraint-the dominance of a single component of the stress tensor. We discuss the implications of our findings for the analysis of elastic sheets under various types of forcing. 相似文献
213.
Combinations of vanadium(IV, V) centred oxofluoropolyhedra with arsenate(V) tetrahedra produce complex structures consisting of sheets, strongly corrugated layers and hexagonal arrays of isolated, 33 ? diameter tubes. 相似文献
214.
Eleni Constantinou Ioannis Pashalidis 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(1):261-265
The aim of this study is the separation and pre-concentration of thorium from aqueous solutions by cloud point extraction
(CPE) and its the radiometric determination by liquid scintillation counting (LSC). For CPE, tributyl phosphate (TBP) was
used as the complexing agent and (1,1,3,3-Tetramethylbutyl)phenyl-polyethylene glycol (Triton X-114) as the surfactant. The
radiometric measurements were performed after phase separation by mixing of the surfactant phase with the liquid scintillation
cocktail. The effect of experimental conditions such as pH, ionic strength (e.g. [NaCl]) and the presence of other chemical
species (e.g. Ca2+ and Fe3+ ions, and humic acid colloids) on the CPE separation recovery have been investigated at constant reactant ratio (m(TBP)/m(Triton) = 0.1). According to the experimental results the maximum chemical recovery is (60 ± 5)% at pH 3. Regarding the other
parameters, generally Ca2+ and Fe3+ ions as well as the presence of colloidal species in solution (even at low concentrations) results in significant decrease
of the chemical recovery of uranium. On the other hand increasing NaCl concentration leads to enhancement of chemical recovery.
Generally, the method could be applied successfully for the radiometric determination of thorium in water solutions with relatively
increased thorium content. 相似文献
215.
216.
Despina Charalambous Nicolas-George Homer Eliades Michalis Christoforou Eleni Kakouri Charalabos Kanakis Petros A. Tarantilis Maria Pantelidou 《Molecules (Basel, Switzerland)》2022,27(9)
This study aimed to determine the chemical composition of different types of tissue of Cedrus brevifolia Henry (Pinaceae) methanolic extracts, namely needles, twigs, branches, and bark. Cedrus brevifolia is a narrow endemic coniferous tree species of Cyprus, growing in a sole population in the mountainous area of Paphos Forest. Chemical analysis of the extracts was performed using liquid chromatography combined with time-of-flight high-resolution mass spectrometry (LC/Q-TOF/HRMS). The majority of the 36 compounds tentatively identified belonged to the flavonoids family. The extract of needles was the richest extract in terms of secondary metabolites. The extracts were studied for their antioxidant activity using the DPPH free radical scavenging assay. Additionally, the antibacterial activity was evaluated by determining both the minimum inhibitory concentration and the minimum bactericidal concentration against Staphylococcus aureus and Escherichia coli. All extracts demonstrated antioxidant property, while bark gave the highest antioxidant capacity (IC50 value of 0.011 mg/mL) compared to the other tissues. Antibacterial activity was observed against both types of bacteria, with the extract of branches presenting the strongest activity against S. aureus (MIC, 0.097 mg/mL and MBC, 0.195 mg/mL). This is the first time that extracts of needles, twigs, branches, and bark of C. brevifolia are compared regarding their chemical composition as well as their antimicrobial and antioxidant properties. 相似文献