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941.
Maximilian Weiss Thomas Glechner Victor U. Weiss Helmut Riedl Andreas Limbeck 《Molecules (Basel, Switzerland)》2022,27(10)
The increased demand for sustainability requires, among others, the development of new materials with enhanced corrosion resistance. Transition metal diborides are exceptional candidates, as they exhibit fascinating mechanical and thermal properties. However, at elevated temperatures and oxidizing atmospheres, their use is limited due to the fact of their inadequate oxidation resistance. Recently, it was found that chromium diboride doped with silicon can overcome this limitation. Further improvement of this protective coating requires detailed knowledge regarding the composition of the forming oxide layer and the change in the composition of the remaining thin film. In this work, an analytical method for the quantitative measurement of depth profiles without using matrix-matched reference materials was developed. Using this approach, based on the recently introduced online-LASIL technique, it was possible to achieve a depth resolution of 240 nm. A further decrease in the ablation rate is possible but demands a more sensitive detection of silicon. Two chromium diboride samples with different Si contents suffering an oxidation treatment were used to demonstrate the capabilities of this technique. The concentration profiles resembled the pathway of the formed oxidation layers as monitored with transmission electron microscopy. The stoichiometry of the oxidation layers differed strongly between the samples, suggesting different processes were taking place. The validity of the LASIL results was cross-checked with several other analytical techniques. 相似文献
942.
Funmilola Alabi Elijah G. Kiarie Caven Mguvane Mnisi Victor Mlambo 《Molecules (Basel, Switzerland)》2022,27(14)
The utility of the marama bean (MB) as an alternative protein source to soybean (SB) can be limited by the high concentration of trypsin inhibitors (TI). The physical treatment of MB has the potential to ameliorate the antinutritional activities of TI and modify other chemical components. Thus, this study investigated the effects of physical treatments on the chemical components and trypsin inhibitor activity (TIA) of raw MB and SB. The bean substrates were subjected to each of the following treatment methods: (1) room temperature (20–22 °C) soaking for 24 h; (2) electric stove cooking at 100 °C for 10, 20, and 30 min; (3) steam autoclaving at a temperature of 110 °C and pressure of 7 pounds per square inch (psi), as well as a temperature of 121 °C and 7 psi for 5, 15, and 30 min; (4) pre-soaked autoclaving at 110 °C (7 psi) and 121 °C (17 psi) for 5, 15, and 30 min. Treated MB and SB had greater (p < 0.05) crude protein content than untreated samples. All the treatments (except 24 h soaking of MB) reduced (p < 0.05) the TIA and ash content. Marama and SB are similar in protein content, but their amino acids profile and TIA are quite different. Soaking for 24 h was less effective in reducing TIA in MB and SB, compared to the thermal methods, and it was detrimental to the ash and amino acids profile of the two beans. Soaking prior to autoclaving yielded beans with the lowest TI concentrations. In conclusion, thermal methods reduced the TI contents and modified the level of proximate components and amino acids profile of the beans. 相似文献
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945.
Victor Pena Ribeiro Caroline Arruda Jonas Joaquim Mangabeira da Silva Jennyfer Andrea Aldana Mejia Niege Araari Jacometti Cardoso Furtado Jairo Kenupp Bastos 《Biomedical chromatography : BMC》2019,33(2)
Copaifera is a tree that produces an oleoresin that has great historical and economic importance. These oleoresins display several pharmacological properties, such as anti‐inflammatory and antimicrobial, among others. The commercialization of Copaifera oleoresin occurs, in many cases, without any quality control, which facilitates its adulteration. Validated analytical methods can provide a safe quality control. In this work, the 800 Automatic Spinning Band Distillation equipment was used to perform the fractionation of the volatile oils obtained by hydrodistillation of Copaifera multijuga, C. paupera, C. Publifora and C. langsdorffii, aiming to isolate and purify the major compounds present in these oils. For purification, classical column chromatography was used, furnishing six isolated sesquiterpenes. The sesquiterpenes were used as standards in the development and validation of the method by GC–FID. The evaluated parameters were selectivity, linearity, precision, accuracy and robustness and they are all in accordance with ANVISA and International Conference on Harmonization guidelines. The developed method is reliable for the quantification of sesquiterpenes in Copaifera oleoresins. Both volatile oils and isolated sesquiterpenes had their minimum inhibitory concentration determined against strains of Gram‐negative and Gram‐positive bacteria and yeasts. Copaifera langsdorffi oleoresin was the only one active against all of the evaluated microorganisms, displaying good antimicrobial potential. 相似文献
946.
Neves Junior Alex Dweck Jo Filho Romildo Dias Toledo Ellis Brian Li Victor 《Journal of Thermal Analysis and Calorimetry》2019,135(1):97-109
Journal of Thermal Analysis and Calorimetry - The present study has evaluated the rheological behavior of an oil-based (5W50) hybrid nanofluid [magnesium oxide (65%)–multi-walled carbon... 相似文献
947.
Dr. Solène Gentil Dr. Pierre Rousselot-Pailley Ferran Sancho Dr. Viviane Robert Dr. Yasmina Mekmouche Prof. Victor Guallar Dr. Thierry Tron Dr. Alan Le Goff 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(21):4798-4804
A maximization of a direct electron transfer (DET) between redox enzymes and electrodes can be obtained through the oriented immobilization of enzymes onto an electroactive surface. Here, a strategy for obtaining carbon nanotube (CNTs) based electrodes covalently modified with perfectly control-oriented fungal laccases is presented. Modelizations of the laccase-CNT interaction and of electron conduction pathways serve as a guide in choosing grafting positions. Homogeneous populations of alkyne-modified laccases are obtained through the reductive amination of a unique surface-accessible lysine residue selectively engineered near either one or the other of the two copper centers in enzyme variants. Immobilization of the site-specific alkynated enzymes is achieved by copper-catalyzed click reaction on azido-modified CNTs. A highly efficient reduction of O2 at low overpotential and catalytic current densities over −3 mA cm−2 are obtained by minimizing the distance from the electrode surface to the trinuclear cluster. 相似文献
948.
Pumza Mente Victor Mashindi Tumelo N. Phaahlamohlaka Thabo N. Monyatsi Roy P. Forbes Neil J. Coville 《ChemistryOpen》2021,10(6):608-608
The Cover Feature shows the cobalt oxide nanoparticles supported both inside and outside hollow carbon spheres (HCSs), which serve as a catalyst for benzyl alcohol oxidation. A metal oxidation step prior to the reaction enhanced the catalytic activity of benzyl alcohol which was used as a model reaction for the catalysts. Both catalysts showed similar activity and selectivity (to benzaldehyde) whether placed inside or outside the HCSs (70% selectivity at 50% conversion). No poisoning was observed due to product build up in the HCSs. More information can be found in the Full Paper by Pumza Mente et al. 相似文献
949.
Fang Cui Gujarati Himali Osinaga Faith Hsia Victor Cheney Marcos A. Kharel Madan K. 《Research on Chemical Intermediates》2021,47(9):3673-3690
Research on Chemical Intermediates - A routine release of slow-degrading agrochemicals in the environment has resulted in their gradual accumulation posing a major threat both to the terrestrial... 相似文献
950.
Stanislav Naryzhny Nikolay Klopov Natalia Ronzhina Elena Zorina Victor Zgoda Olga Kleyst Natalia Belyakova Olga Legina 《Electrophoresis》2020,41(12):1118-1124
The human proteome is composed of a diverse and heterogeneous range of gene products/proteoforms/protein species. Because of the growing amount of information about proteoforms generated by different methods, we need a convenient approach to make an inventory of the data. Here, we present a database of proteoforms that is based on information obtained by separation of proteoforms using 2DE followed by shotgun ESI–LC–MS/MS. The database's principles and structure are described. The database is called “2DE-pattern” as it contains multiple isoform-centric patterns of proteoforms separated according to 2DE principles. The database can be freely used at http://2de-pattern.pnpi.nrcki.ru . 相似文献