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91.
João P. F. Mota Viviane G. P. Ribeiro Fernando L. F. da Silva Antônio E. C. Junior Davi R. Oliveira Lloyd R. V. Kotzebue 《分离科学与技术》2016,51(14):2473-2483
The present work made a comparative study between two purification methods, column chromatography and recrystallization, for compounds derived from cardanol, a by-product of the cashew industry (Anacardium occidentale L.). The compounds were successfully synthesized and characterized, focusing our attention to results obtained in terms of yield, purity, generation of solid waste and amount of solvent used in each purification process. For all the synthesized compounds, the amount of solvent used was greatly reduced in the recrystallization process, with purities above 80%, when compared to chromatographic column, which still demands high amounts of eluent. 相似文献
92.
Kamilla Soares de Mendonça João Renato de Jesus Junqueira Michel Cardoso de Angelis Pereira Marina Barbosa Vilela 《Drying Technology》2016,34(4):386-394
Osmotic dehydration assisted by ultrasound (ODAU) at low temperatures reduces water activity (aw) and maintains nutrients. The influence of solution concentration (SC; 20 to 60° Brix, xylitol and sorbitol) and ultrasound application time (tus, 0 to 40 min) in ODAU of yacon was studied with the aid of a response surface method. The optimum condition with respect to mass transfer parameters, aw, and fructan retention was SC of 60° Brix for both solutions and tus of 2.67 min for xylitol samples and 0 min for sorbitol samples. The application of ultrasound improved dehydration but resulted in depolymerization of fructans. 相似文献
93.
Nitroarenes as Antitubercular Agents: Stereoelectronic Modulation to Mitigate Mutagenicity 下载免费PDF全文
Dr. Sudhir Landge Dr. Vasanthi Ramachandran Dr. Anupriya Kumar Dr. João Neres Kannan Murugan Dr. Claire Sadler Dr. Mick D. Fellows Vaishali Humnabadkar Dr. Prakash Vachaspati Dr. Anandkumar Raichurkar Sreevalli Sharma Sudha Ravishankar Supreeth Guptha Dr. Vasan K. Sambandamurthy Dr. Tanjore S. Balganesh Dr. Bheemarao G. Ugarkar Dr. V. Balasubramanian Dr. Balachandra S. Bandodkar Dr. Manoranjan Panda 《ChemMedChem》2016,11(3):331-339
Nitroarenes are less preferred in drug discovery due to their potential to be mutagenic. However, several nitroarenes were shown to be promising antitubercular agents with specific modes of action, namely, nitroimidazoles and benzothiazinones. The nitro group in these compounds is activated through different mechanisms, both enzymatic and non‐enzymatic, in mycobacteria prior to binding to the target of interest. From a whole‐cell screening program, we identified a novel lead nitrobenzothiazole (BT) series that acts by inhibition of decaprenylphosphoryl‐β‐d ‐ribose 2′‐epimerase (DprE1) of Mycobacterium tuberculosis (Mtb). The lead was found to be mutagenic to start with. Our efforts to mitigate mutagenicity resulted in the identification of 6‐methyl‐7‐nitro‐5‐(trifluoromethyl)‐1,3‐benzothiazoles (cBTs), a novel class of antitubercular agents that are non‐mutagenic and exhibit an improved safety profile. The methyl group ortho to the nitro group decreases the electron affinity of the series, and is hence responsible for the non‐mutagenic nature of these compounds. Additionally, the co‐crystal structure of cBT in complex with Mtb DprE1 established the mode of binding. This investigation led to a new non‐mutagenic antitubercular agent and demonstrates that the mutagenic nature of nitroarenes can be solved by modulation of stereoelectronic properties. 相似文献
94.
Park Jongmyung Jo Youngdo Park Gyesoon 《Journal of Mechanical Science and Technology》2018,32(3):1187-1194
Journal of Mechanical Science and Technology - Regarding mine ventilation in a tunnel with one mining face, the turbulent flow structure and Mean age of air (MAA) of fresh air discharged from the... 相似文献
95.
Jiadong Zang Ming Li Derek C. Sinclair Wook Jo Jürgen Rödel 《Journal of the American Ceramic Society》2014,97(5):1523-1529
The electrical and dielectric properties of (1 ? x)(0.94Bi1/2Na1/2TiO3–0.06BaTiO3)–x(K0.5Na0.5NbO3) with x = 0, 0.03, 0.09, 0.18 have been investigated by impedance spectroscopy over a wide temperature range. The dc conductivity of the ceramics follows the Arrhenius law with an activation energy ranging from ~1.20 to 1.50 eV. Measurements under different atmospheres show the materials exhibit n‐type semiconducting behavior at elevated temperatures. The presence of a highly polarizable phase for all compositions is revealed by electric modulus (M″) spectra. The Burns temperature decreases with increasing KNN content. The change in temperature‐dependent permittivity with composition is explained by the difference in thermal evolution of polar nanoregions induced by the addition of KNN. 相似文献
96.
Quantitative analysis of microbial community structure in two-phase anaerobic digesters treating food wastewater 总被引:1,自引:0,他引:1
Woong Kim Byung-Gon Ryu Sungwhan Kim Sung-Woon Heo Donghyun Kim Jungmin Kim Haechan Jo Jong-Hee Kwon Ji-Won Yang 《Korean Journal of Chemical Engineering》2014,31(3):381-385
An acidogenic reactor with a 0.5-L working volume and a methanogenic digester with a 5-L of working volume were operated for 150 days on a continuous mode to investigate the structure of a microbial community during food wastewater treatment. During the steady state of anaerobic digestion, volatile solids (VS) removal efficiency in the pilot plant was approximately 65%. The bacterial population was higher than any other methanogens detected during the entire anaerobic process and treatment of raw food wastewater. Methanomicrobiales (MMB), Methanosarcinales (MSL), and Methanobacteriales (MBT) were detected during digestion. The methanogenic population present in the acidogenic reactor was directly affected by the archaeal community in raw food wastewater. However, the shift of microbial community in the methanogenic digester was relatively gradual. The performance of methanogenic digester might be more related to the change of microbial metabolism affected by the physicochemical properties of the input substrate. 相似文献
97.
The effect of the viscosity ratio of the dispersed LCP phase to the polystyrene/poly(phenylene oxide) (PS/PPO) thermoplastic matrix on the rheological, morphological, and resultant mechanical properties of the LCP blends was investigated. The viscosity of PS/PPO is largely dependent on the blend composition, so that different levels of viscosity ratios of dispersed LCP phase to PS/PPO thermoplastic matrix are obtained by using PS/PPO premixtures of different blend ratios as a thermoplastic matrix. When the viscosity of the LCP dispersed phase is lower than that of the thermoplastic matrix, finely distributed fibril structure of LCP is obtained. Tensile modulus of injection molded specimens show a positive deviation from the additive rule when the viscosity ratio (ηLCP/ηmatrix) is smaller than unity. These improvements in tensile modulus are attributed to the formation of finely distributed LCP fibrils. © 1996 John Wiley & Sons, Inc. 相似文献
98.
The migration pattern of spawners of brown trout (Salmo trutta) in relation to water flow was analysed by radio-tracking in the regulated River Gudbrandsdalslågen, Norway. During the upstream spawning migration in the high flow period, trout (2–12 kg) were caught, tagged and released 15 km downstream of a fish ladder at the Hunderfossen waterfall. The released fish displayed a systematic and directional upstream movement to the outlet of the tunnel from the hydroelectricity plant. In autumn and winter there is a minimum water discharge of 20–2 m3/s on p.s. in the river between the dam and the outlet of the tunnel, which has a discharge of 200–300 m3/s. When the water flowing over the Hunderfossen dam decreased to 20 m3/s, the ascent of brown trout up the river stopped and fish periodically entered the power plant tunnel. To determine the flow necessary to attract fish into the spawning reach above the tunnel outlet, two experiments were undertaken using 12 and 17 radio-tagged trout. In the first experiment, 60 m3/s of water released for 24 h resulted in the migration of 50% of the trout up the river. The second experiment, releasing 60 m3/s for 24 h, followed by 30 m3/s for 24 h two days later, resulted in the migration of 60% of the trout. Only one fish ascended the river at a flow of 30 m3/s. It is recommended that a repeated release of water at 60 m3/s is made in periods of minimum water discharge to save the spawning migration. The results demonstrate the advantage of using radio-tracking in experiments dealing with fish migration in relation to water-flow management. 相似文献
99.
100.
Vivek Pandey Michael Seese João M. Maia David A. Schiraldi 《Polymer Engineering and Science》2020,60(10):2511-2516
Three chain extenders, pyromellitic dianhydride (PMDA), ethylene carbonate (EC), and a polymeric-epoxide, were investigated for improving recycled p(ethylene terephthalate) (r-PET) properties with melt extrusion. The amount of additives and processing temperatures were also varied to check for melt degradation. Small amplitude oscillatory shear experiments were performed to probe rheological changes with different chain extenders. Capillary rheometry with haul-off was also performed to measure extensional viscosity and melt strength. Higher loadings of the chain extenders were found to improve properties of r-PET. These chain extenders definitely increased melt viscosities when incorporated at the higher level of the ranges examined, matching that of virgin PET. EC addition resulted in high shear thinning of the polymer. Epoxy and PMDA added to r-PET produced products with the same extensional viscosity as v-PET. Haul-off experiments demonstrate superior performance by epoxy-modified r-PET compared to v-PET. 相似文献