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1.
Hugo F. Franzen Mirtha X. Umaña J.R. McCreary R.J. Thorn 《Journal of solid state chemistry》1976,18(4):363-368
The first-row transition-metal monosulfides and alkaline-earth chalcogenides were studied by means of X-ray photoelectron spectroscopy. It is shown that the bonding in the alkaline earth compounds is relatively ionic with XPS evidence for significant charge separation. On the other hand, transition metal sulfides, with the exception of MnS, appear to be principally metallic with little or no charge separation. Values for the inner orbital binding energy shifts are reported for a large number of monochalcogenides. 相似文献
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Mirtha Navarro-Hoyos Elizabeth Arnez-Serrano Silvia Quesada-Mora Gabriela Azofeifa-Cordero Krissia Wilhelm-Romero María Isabel Quirs-Fallas Diego Alvarado-Corella Felipe Vargas-Huertas Andrs Snchez-Kopper 《Molecules (Basel, Switzerland)》2021,26(21)
There is an increased interest in plum research because of their metabolites’ potential bioactivities. In this study, the phenolic profiles of Prunus domestica commercial cultivars (Methley, Pisardii and Satsuma) in Costa Rica were determined by Ultra Performance Liquid Chromatography coupled with High Resolution Mass Spectrometry using a quadrupole-time-of-flight analyzer (UPLC-ESI-QTOF MS) on enriched phenolic extracts obtained through Pressurized Liquid Extraction (PLE) under acidic and neutral extraction conditions. In total, 41 different phenolic compounds were identified in the skin and flesh extracts, comprising 11 flavan-3-ols, 14 flavonoids and 16 hydroxycinnamic acids and derivatives. Neutral extractions for the skins and flesh from all of the cultivars yielded a larger number of compounds, and were particularly rich in the number of procyanidin trimers and tetramers when compared to the acid extractions. The total phenolic content (TPC) and antioxidant potential using the DPPH and ORAC methods exhibited better results for neutral extracts with Satsuma skins and Methley flesh, which showed the best values (685.0 and 801.6 mg GAE/g extract; IC50 = 4.85 and 4.39 µg/mL; and 12.55 and 12.22 mmol TE/g extract, respectively). A Two-Way ANOVA for cytotoxicity towards AGS gastric adenocarcinoma and SW620 colon adenocarcinoma indicated a significant difference (p < 0.05) for PLE conditions, with better results for neutral extractions, with Satsuma skin delivering the best results (IC50 = 60.7 and 46.7 µg/mL respectively) along with Methley flesh (IC50 = 76.3 and 60.9 µg/mL, respectively). In addition, a significant positive correlation was found between TPC and ORAC (r = 0.929, p < 0.05), as well as a significant negative correlation (p < 0.05) between TPC and cytotoxicity towards AGS and SW620 cell lines (r = −0.776, and −0.751, respectively). A particularly high, significant, negative correlation (p < 0.05) was found between the number of procyanidins and cytotoxicity against the AGS (r = −0.868) and SW620 (r = −0.855) cell lines. Finally, the PCA clearly corroborated that neutral extracts are a more homogenous group exhibiting higher antioxidant and cytotoxic results regardless of the part or cultivar; therefore, our findings suggest that PLE extracts under neutral conditions would be of interest for further studies on their potential health benefits. 相似文献
3.
Léon Ghosez Jean-Pierre Antoine Etienne Deffense Mirtha Navarro Valery Libert Martin J. ODonnell William A. Bruder Katherine Willey Krzysztof Wojciechowski 《Tetrahedron letters》1982,23(41):4255-4258
The Sciff base derived from glycine ethyl ester and p-chlorobenzaldehyde can be alkylated by the ion-pair extraction method as well as under catalytic liquid-liquid or solid-liquid phase-transfer conditions. This imine is compared with the corresponding benzophenone Schiff base. 相似文献
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Mirtha Orozco Alberto Camacho Salvador Canzonieri 《Physics and Chemistry of Liquids》2018,56(3):353-362
Densities and viscosities of binary liquid mixtures of propyl propanoate + heptane and propyl propanoate + octane at temperatures of 278.15, 283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15 and 323.15 K have been measured at atmospheric pressure over the entire range of composition. Using these experimental data, the excess molar volumes and the viscosity deviation have been calculated. The experimental data of density and viscosity at different investigated temperatures were mathematically represented by the Jouyban–Acree model. The mean relative deviation (MRD) was used as an error criterion, and the MRD values for data correlation of density and viscosity at different investigated temperatures are less than 0.03% and 0.50%, respectively. Excess molar volumes and viscosity deviations were correlated with Redlich–Kister equation. The calculated data point out the absence of speci?c interactions between the molecules of different components, which would be slightly weaker compared to the interactions in the pure components. 相似文献
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Vallejos Mara Evangelina Olmos Graciela Viviana Taleb Mara Claudia Felissia Fernando Esteban Ehman Nanci Vanesa Peresin Maria Soledad Area Mara Cristina Maximino Mirtha Graciela 《Cellulose (London, England)》2022,29(8):4645-4659
Cellulose - This study assesses the possibility of obtaining regenerated cellulose products (beads and films) from eucalyptus sawdust dissolving pulps produced by non-conventional processes,... 相似文献
8.
Graciela D. Venera Claudia Machalinski Hugo Zum’arraga Mirtha J. Biscoglio Jim’enez de Bonino 《Applied biochemistry and biotechnology》1997,68(3):207-216
Further characterization of an aspartyl protease fromMucor bacilliformis with milk-clotting activity was performed. An extinction coefficient, ε278 cm = 1.61 mL/mg/cm, a molecular mass of 35,400 Da and a pI of 5.2 were determined. Proteolytic activity and kinetic parameters
were evaluated by using the hexapeptide Leu-Ser-pNO2-Phe-Nle-Ala-Leu-OMe as the substrate. The effect of pH and temperature on peptide cleavage, as well as protease heat stability,
was determined. Such properties, taken as a whole, indicate that theM. bacilliformis protease can be considered a potential substitute for bovine chymosin in cheese manufacture. 相似文献
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Mirtha Navarro-Hoyos Elizabeth Arnez-Serrano Silvia Quesada-Mora Gabriela Azofeifa-Cordero Krissia Wilhelm-Romero Maria Isabel Quirs-Fallas Diego Alvarado-Corella Felipe Vargas-Huertas Andrs Snchez-Kopper 《Molecules (Basel, Switzerland)》2021,26(23)
There is increasing interest in research into fruits as sources of secondary metabolites because of their potential bioactivities. In this study, the phenolic profiles of Malus domestica Anna and Jonagold cultivars from Costa Rica were determined by Ultra Performance Liquid Chromatography coupled with High Resolution Mass Spectrometry (HRMS) using a quadrupole-time-of-flight analyzer (UPLC-QTOF-ESI MS), on enriched-phenolic extracts from skins and flesh, obtained through Pressurized Liquid Extraction (PLE). In total, 48 different phenolic compounds were identified in the skin and flesh extracts, comprising 17 flavan-3-ols, 12 flavonoids, 4 chalcones, 1 glycosylated isoprenoid and 14 hydroxycinnamic acids and derivatives. Among extracts, the flesh of Jonagold exhibits a larger number of polyphenols and is especially rich in procyanidin trimers, tetramers and pentamers. Evaluating total phenolic content (TPC) and antioxidant activities using ORAC and DPPH procedures yields higher values for this extract (608.8 mg GAE/g extract; 14.80 mmol TE/g extract and IC50 = 3.96 µg/mL, respectively). In addition, cytotoxicity evaluated against SW620 colon cancer cell lines and AGS gastric cancer cell lines also delivered better effects for Jonagold flesh (IC50 = 62.4 and 60.0 µg/mL, respectively). In addition, a significant negative correlation (p < 0.05) was found between TPC and cytotoxicity values against SW620 and AGS adenocarcinoma (r = −0.908, and −0.902, respectively). Furthermore, a significant negative correlation (p < 0.05) was also found between the number of procyanidins and both antioxidant activities and cytotoxicity towards SW620 (r = −0.978) and AGS (r = −0.894) cell lines. These results align with Jonagold flesh exhibiting the highest abundance in procyanidin oligomers and yielding better cytotoxic and antioxidant results. In sum, our findings suggest the need for further studies on these Costa Rican apple extracts—and particularly on the extracts from Jonagold flesh—to increase the knowledge on their potential benefits for health. 相似文献
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Liliana B. Areces Mirtha Biscoglio De Jiménez Bonino Marina A. A. Parry Elda R. Fraile Héctor M. Fernández Osvaldo Cascone 《Applied biochemistry and biotechnology》1992,37(3):283-294
An acid protease having milk clotting activity has been isolated fromMucor bacilliformis cultures. The enzyme was basically purified by ionic exchange chromatography. An average yield of 29 mg purified product
was obtained from 100 mL crude extract. As purity criteria, SDS-PAGE, reverse-phase HPLC, and N-terminal analysis were performed.
The protease is a protein composed of a single polypeptide chain with glycine at the N-terminus. The mol wt is approx 32,000,
and its amino acid composition is very similar to those of other fungal proteases. As expected, its clotting activity was
drastically inhibited by pepstatin A action. On the other hand, its instability against heat treatment and its clotting/proteolytic
activity ratio indicate that it may be considered as a potential substitute for bovine chymosin. Index Entries:Mucor bacilliformis protease; milk clotting enzyme; acid protease; fungal protease; aspartyl protease. 相似文献