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981.
Talita Corrêa Nazareth Aline Gomes de Oliveira Paranhos Lucas Rodrigues Ramos Edson Luiz Silva 《Applied biochemistry and biotechnology》2018,186(2):400-413
This study evaluated the propionic acid (HPr) production from crude glycerol (CG) (5000 mg L?1) in an anaerobic fluidized bed reactor (AFBR). Grounded tire particles (2.8–3.35 mm) were used as support material for microbial adhesion. The reactor was operated with hydraulic retention times (HRT) varying from 8 to 0.5 h under mesophilic (30 °C) conditions. The HPr was the main metabolite produced, increasing in composition from 66.5 to 99.6% by decreasing the HRT from 8 to 0.5 h. Other metabolic products were 1,3-propanediol, with a maximum of 29.4% with an HRT of 6 h, ethanol, acetic, and butyric acids. The decrease in HRT from 8 to 0.5 h decreased the HPr yield, with a maximum of 0.48?±?0.06 g HPr g COD?1 and an HRT of 6 h, and favored HPr productivity, with a maximum of 4.09?±?1.24 g L?1 h?1 and HRT of 0.5 h. In the biogas, the H2 content increased from 12.5 to 81.2% by decreasing the HRT from 8 to 0.5 h. These results indicate the potential application of the AFBR for HPr production using an immobilized mixed culture. 相似文献
982.
de Souza Poliana Santos Clain Almir Faria Filho Octávio Luiz Trindade de Oliveira Estela Maria Delgado Jose Ubiratan Lopes Ricardo Tadeu 《Journal of Radioanalytical and Nuclear Chemistry》2019,321(3):851-856
Journal of Radioanalytical and Nuclear Chemistry - The production of environmental reference materials such as soil, sediment, water and vegetation containing radionuclides for interlaboratory... 相似文献
983.
984.
Luiz F. A. Santos Amadeu H. Iglesias Eduardo J. Pilau Alexandre F. Gomes Fabio C. Gozzo 《Journal of the American Society for Mass Spectrometry》2010,21(12):2062-2069
Traveling-wave ion mobility (TWIM) coupled to mass spectrometry (MS) has emerged as a powerful tool for structural and conformational
analysis of proteins and peptides, allowing the analysis of isomeric peptides (or proteins) with the same sequence but modified
at different residues. This work demonstrates the use of the novel TWIM-MS technique to separate isomeric peptide ions derived
from chemical cross-linking experiments, which enables the acquisition of distinct product ion spectra for each isomer, clearly
indicating modification on different sites. Experiments were performed with four synthetic peptides, for which variable degrees
of mobility separation were achieved. In cases of partially overlapping mobility arrival time distributions (ATDs), extracting
the ATDs of fragment ions belonging to each individual isomer allowed their separation into two distinct ATDs. Accumulation
over regions from the specific ATDs generates the product ion spectrum of each isomer, or a spectrum highly enriched in their
fragments. The population of both modified peptide isomers was correlated with the intrinsic reactivities of different Lys
residues from reactions conducted at different pH conditions. 相似文献
985.
Ana Carolina Corrêa Eliangela de Morais Teixeira Luiz Antonio Pessan Luiz Henrique Capparelli Mattoso 《Cellulose (London, England)》2010,17(6):1183-1192
Curaua nanofibers extracted under different conditions were investigated. The raw fibers were mercerized with NaOH solutions;
they were then submitted to acid hydrolysis using three different types of acids (H2SO4, a mixture of H2SO4/HCl and HCl). The fibers were analyzed by cellulose, lignin and hemicellulose contents; viscometry, X-ray diffraction (XRD)
and thermal stability by thermogravimetric analysis (TG). The nanofibers were morphologically characterized by transmission
electron microscopy (TEM) and their surface charges in suspensions were estimated by Zeta-potential. Their degree of polymerization
(DP) was characterized by viscometry, crystallinity by XRD and thermal stability by TG. Increasing the NaOH solution concentration
in the mercerization, there was a decrease of hemicellulose and lignin contents and consequently an increase of cellulose
content. XRD patterns presented changes in the crystal structure from cellulose I to cellulose II when the fibers were mercerized
with 17.5% NaOH solution. All curaua nanofibers presented a rod-like shape, an average diameter (D) of 6–10 nm and length
(L) of 80–170 nm, with an aspect ratio (L/D) of around 13–17. The mercerization of fibers with NaOH solutions influenced the
crystallinity index and thermal stability of the resulting nanofibers. The fibers mercerized with NaOH solution 17.5% resulted
in more crystalline nanofibers, but thermally less stable and inferior DP. The aggregation state increases with the amount
of HCl introduced into the extraction, due to the decrease of surface charges (as verified by Zeta Potential analysis). However,
this release presented nanofibers with better thermal stability than those whose acid hydrolysis was carried out using only
H2SO4. 相似文献
986.
Alexandre G. S. Prado Aline O. Moura Rômulo D. A. Andrade Igor C. Pescara Valéria S. Ferreira Elaine A. Faria Augusto H. A. de Oliveira Esmeralda Y. A. Okino Luiz F. Zara 《Journal of Thermal Analysis and Calorimetry》2010,99(2):681-687
Brazilian sawdust samples (Caryocar spp.; Manilkara spp.; and Tabebuia spp.) have been used for Cr(VI) adsorption from water. The series of adsorption isotherms were adjusted to modified Langmuir
equation. Thermodynamic data of interactions were studied by the calorimetric titration of Cr(VI) in aqueous solution. All
liquid/solid interface adsorptions were entalpically and entropically driven. These sawdust samples were also used to remove
chromium from tannery wastewater. The application of Caryocar spp.; Manilkara spp.; and Tabebuia spp. reduced the amount of chromium from 2.11 ± 0.18 mg L−1 to 1.15 ± 0.10; 0.29 ± 0.02 and 0.26 ± 0.02 mg L−1, respectively. 相似文献
987.
Anticariogenic properties of ent-pimarane diterpenes obtained by microbial transformation 总被引:1,自引:0,他引:1
Severiano ME Simão MR Porto TS Martins CH Veneziani RC Furtado NA Arakawa NS Said S de Oliveira DC Cunha WR Gregório LE Ambrósio SR 《Molecules (Basel, Switzerland)》2010,15(12):8553-8566
In the present work, the anticariogenic activities of three pimarane-type diterpenes obtained by fungal biotransformation were investigated. Among these metabolites, ent-8(14),15-pimaradien-19-ol was the most active compound, displaying very promising MIC values (ranging from 1.5 to 4.0 μg mL(-1)) against the main microorganisms responsible for dental caries: Streptococcus salivarius, S. sobrinus, S. mutans, S. mitis, S. sanguinis, and Lactobacillus casei. Time kill assays performed with ent-8(14),15-pimaradien-19-ol against the primary causative agent S. mutans revealed that this compound only avoids growth of the inoculum in the first 12 h (bacteriostatic effect). However, its bactericidal effect is clearly noted thereafter (between 12 and 24 h). The curve profile obtained by combining ent-8(14),15-pimaradien-19-ol and chlorhexidine revealed a significant reduction in the time necessary for killing S. mutans compared with each of these two chemicals alone. However, no synergistic effect was observed using the same combination in the checkerboard assays against this microorganism. In conclusion, our results point out that ent-8(14),15-pimaradien-19-ol is an important metabolite in the search for new effective anticariogenic agents. 相似文献
988.
Barreto AS da Silva RL Dos Santos Silva SC Rodrigues MO de Simone CA de Sá GF Júnior SA Navickiene S de Mesquita ME 《Journal of separation science》2010,33(23-24):3811-3816
The metal-organic framework (∞)[(La(0.9)Eu(0.1))(2)(DPA)(3)(H(2)O)(3)] was tested for extraction of pyrimicarb, procymidone, malathion, methyl parathion and α- and β-endosulfan from lettuce, with analysis using GC/MS in SIM mode. Experiments were carried out in triplicate at two fortification levels (0.1 and 0.5?mg/kg), and resulted in recoveries in the range of 78-107%, with RSD values between 1.6 and 8.0% for (∞)[(La(0.9)Eu(0.1))(2)(DPA)(3)(H(2)O)(3)] sorbent. Detection and quantification limits ranged from 0.02 to 0.05?mg/kg and from 0.05 to 0.10?mg/kg, respectively, for the different pesticides studied. The method developed was linear over the range tested (0.05-10.0?μg/mL), with correlation coefficients ranging from 0.9990 to 0.9997. Comparison between (∞)[(La(0.9)Eu(0.1))(2)(DPA)(3)(H(2)O)(3)] and conventional sorbent (silica gel) showed better performance of the (∞)[(La(0.9)Eu(0.1))(2)(DPA)(3)(H(2)O)(3)] polymeric sorbent for all pesticides tested. 相似文献
989.
In this work it a strong evidence of the hydrated electrons production was shown in a film of condensed water, by directing the injection of electrons in localized and/or delocalized water electronic states using a system of high voltage made in laboratory. The results show that the water layers on the silica particles are electrically charged by injection of electrons from a metal electrode when silica is placed in high electric field. This charging process also appears to depend on the thickness of these water layers and of the spatial arrangement required by the silica surface. 相似文献
990.
Luiz C. Dias Sávio M. Pinheiro Marco A.B. Ferreira Andrea M. Aguilar Edward R.T. Tiekink 《Tetrahedron》2009,65(42):8714-1788
Herein we report that good to excellent levels of 1,5-anti stereoinduction are obtained in boron enolate aldol reactions of 1,2-syn β-alkoxy methyl ketones with achiral aldehydes, when the β-alkoxy protecting group is part of a benzylidene acetal. We have also investigated the effects of the ligands on boron, the α-, β-, and γ-substituents and the β-alkoxy protecting group on the boron enolates, using density functional theory (B3LYP) and Møller-Plesset perturbation theory (MP2) calculations. 相似文献