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排序方式： 共有359条查询结果，搜索用时 46 毫秒
61.
Elena Torrieri Silvana Cavella & Paolo Masi 《International Journal of Food Science & Technology》2009,44(5):890-899
In this work, the effect of temperature, oxygen, red coloration process and post-harvest storage time on the respiration rate of fresh-cut Annurca apples was studied to properly develop modified atmosphere packaging. Our results showed that the red coloration process and the post-harvest storage time did not affect the respiration rate or the respiratory quotient of fresh-cut Annurca apples in the range of temperature studied (5–20 °C). A Michaelis–Menten-type equation, with the model constants described by means of an Arrhenius-type relationship, was used for predicting respiration rate on varying the temperature and O2 concentration in the head space. The maximal respiration rate (mL kg h−1 ) (RRmax ) and the O2 % corresponding to values estimated at the reference temperature (12.5 °C), i.e. the average of the experimental temperature ranges, were, respectively, 6.77 ± 0.1 mL kg−1 h−1 and 0.68 ± 0.07% v/v, and the activation energy of the aerobic respiration rate of fresh-cut Annurca apples was estimated at 51 ± 1 kJ mol−1 . The model works well to develop a modified atmosphere for fresh-cut Annurca apples. 相似文献
62.
Complicated nonlinear systems of pde with constraints (called pdae) arise frequently in applications. Missing constraints arising by prolongation (differentiation) of the pdae need to be determined to consistently initialize and stabilize their numerical solution. In this article we review a fast prolongation method, a development of (explicit) symbolic Riquier Bases, suitable for such numerical applications. Our symbolic-numeric method to determine Riquier Bases in implicit form, without the unstable eliminations of the exact approaches, applies to square systems which are dominated by pure derivatives in one of the independent variables. 相似文献
63.
Fernanda Peyronel Joseph Cooney Erzsebet Papp-Szabo Silvana Martini David Pink 《Journal of the American Oil Chemists' Society》2023,100(12):961-974
Three oleogelator molecules (Triacontane (TC), Stearic acid (SA), and Behenyl Lignocerate (BL)) were studied individually, in pairs, or all together to make an oleogel using triolein as the oil. WAXS, SAXS and USAXS were used to elucidate the solid structures from angstroms to a few micrometers. A two-dimensional mapping of atomic positions for each molecule was carried out to understand the crystalline multilayer structures formed. We assumed that the molecules were rigidly extended and that they underwent no significant (hindered) rotations so that the free energy is determined by the Lennard-Jones interactions of closely packed multilayers. TC molecules were predicted to form a tilt angle of , yielding a SAXS line at Å─1, in acceptable agreement with the measured . For SA crystals (predicted) yielding a SAXS line at compared to (observed). No mixed crystals were observed for any pair of molecules or when all three were used. USAXS data showed that SA forms large nanocrystals compared to TC and BL. All three combinations of molecular pairs showed basic scatterers smaller or similar to those of individual molecules. The theory presented here, together with the experimental results, showed why no mixed crystals are formed from two or all three molecules. Data from the USAXS region suggested that, when using all three molecules, a more compact fractal structure was obtained, compared with those if one or two of the molecules were used. 相似文献
64.
Joseph Cooney Isaac Hilton Melissa Marsh Annalisa Jones Silvana Martini 《Journal of the American Oil Chemists' Society》2023,100(3):225-236
The objective of this study was to evaluate the effect of cannabidiol (CBD) on the crystallization behavior and physical properties of various fats. Anhydrous milk fat (AMF), palm oil (PO), palm kernel oil (PKO), and cocoa butter (CB) were chosen for this study, for their unique crystallization behaviors. CBD was added at 1 and 2.5% wt/wt to these fats, and the crystallization behavior was evaluated at 26°C for AMF and PO and at 22°C for PKO and CB. Control samples with no CBD were prepared and evaluated as well. Results show that CBD delayed the crystallization of all fats with the least effect observed for the PO. Slight increases in crystal size were observed with the addition of CBD for all samples. CBD did not affect the melting profile of AMF or CB, but it increased the peak temperature of PO and decreased the enthalpy of PKO. Similarly, hardness was only affected by CBD in PO samples, with harder materials obtained for samples containing 2.5% CBD. The same trend was observed for elasticity. In addition, the elasticity of AMF increased with the addition of CBD but not its hardness. Overall, this study indicates that the effect of CBD on fat crystallization is highly dependent on the type of fat used. Producers of fat-based products that are willing to include CBD in their formulations must carefully control processing conditions to ensure product quality. 相似文献
65.
66.
Prof. Chiara Brullo Dr. Federica Rapetti Prof. Silvana Alfei Dr. Irena Maric Dr. Francesca Rizzelli Dr. Marina Mapelli Dr. Camillo Rosano Dr. Maurizio Viale Prof. Olga Bruno 《ChemMedChem》2020,15(11):961-969
Even though immunotherapy has radically changed the search for anticancer therapies, there are still many different pathways that are open to intervention with traditional small molecules. To expand our investigation in the anticancer field, we report here a new series of compounds in which our previous pyrazole and imidazopyrazole scaffolds are linked to a differently decorated phenyl ring through an acylhydrazone linker. Preliminary tests on the library were performed at the National Cancer Institute (USA) against the full NCI 60 cell panel. The best compounds among the imidazopyrazole series were then tested by immunofluorescence staining for their inhibition of cell proliferation, apoptosis induction, and their effect on the cell cycle and on microtubules. Two compounds, in particular 4-benzyloxy-3-methoxybenzyliden imidazopyrazole-7-carbohydrazide showed good growth inhibition, with IC50 values in the low-micromolar range, and induced apoptosis. Both compounds altered the cell-cycle phases with the appearance of polyploid cells. Immunofluorescence analysis evidenced microtubules alterations; tubulin polymerization assays and docking studies suggested the tubulin system to be the possible, although not exclusive, target of the new acylhydrazone series reported here. 相似文献
67.
68.
Felipe R. Boni Filipe V. Ferreira Ivanei F. Pinheiro Silvana A. Rocco Mauricio L. Sforça Liliane M. F. Lona 《应用聚合物科学杂志》2020,137(45):49416
Here, an alternative route to successfully synthesize polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) is reported. Steglich esterification was used as an effective, metal free approach for coupling carboxylic terminated PS and the hydroxyl end-functionalized PMMA chains obtained by nitroxide-mediated polymerization and atom transfer radical polymerization, respectively. α-Functionalization was obtained using 4,4′-azobis(4-cyanovaleric acid) and 2,2,2-tribromoethanol as initiators. The synthesis of PS-b-PMMA was confirmed by gel permeation chromatography and nuclear magnetic resonance (NMR), while the dependence of the diffusion coefficients of the polymers (PS, PMMA, PS/PMMA blend, and PS-b-PMMA) with their corresponding molecular weights was discussed based on the results of atomic force microscopy-based infrared spectroscopy, differential scanning calorimetry, and spectra of diffusion-ordered NMR spectroscopy. Differently from PS-b-PMMA, a partial segregation was observed for the PS/PMMA blend, affecting its thermal behavior and diffusion coefficient. The study here presented provides an easier and efficient strategy for the synthesis of PS-b-PMMA and new insights into the diffusion of polymers. 相似文献
69.
Tobias E. Schmitzhaus Maria R. Ortega Vega Roberto Schroeder Iduvirges L. Muller Silvana Mattedi Célia de Fraga Malfatti 《工业材料与腐蚀》2020,71(11):1885-1902
The aim of the present study is to evaluate the performance of N-methyl-2-hydroxyethylammonium oleate ([m-2HEA][Ol]) as a corrosion inhibitor for mild steel in a 0.1-mol/L hydrochloric acid solution and also investigate the role of chloride in the inhibition mechanism. This protic ionic liquid (PIL) has formerly shown a high efficiency as a corrosion inhibitor in a neutral chloride medium. Electrochemical and weight loss measurements, surface contact angle determination, scanning electron microscopy, and Raman spectroscopy were used to understand the factors that influence the response of the studied inhibitor. Results revealed that [m-2HEA][Ol] behaves as a mixed-type adsorption inhibitor, by blocking cathodic sites and by modifying the activation energy of the anodic reaction, and it can reach up to 94–97% of inhibition efficiency. PIL adsorption was enhanced by the excess of positive charge of the mild steel. The effect of inhibitor molecule has been discussed to propose a mechanism that explains the inhibitory action of the corrosion inhibitor, pointing out the role of chloride in the inhibition mechanism. 相似文献
70.