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排序方式: 共有155条查询结果,搜索用时 234 毫秒
91.
Katarzyna Rybak Artur Wiktor Mohammad Kaveh Magdalena Dadan Dorota Witrowa-Rajchert Magorzata Nowacka 《Molecules (Basel, Switzerland)》2022,27(7)
The drying process preserves the surplus of perishable food. However, to obtain a good-quality final product, different pretreatments are conducted before drying. Thus, the aim of the study was the evaluation of the effect of thermal (blanching treatments with hot water) and non-thermal technologies (pulsed electric field (PEF) and ultrasound (US)) on the kinetics of the drying process of red bell pepper. The convective and microwave–convective drying were compared based on quality parameters, such as physical (water activity, porosity, rehydration rate, and color) and chemical properties (total phenolic content, total carotenoids content, antioxidant activity, and total sugars content). The results showed that all of the investigated methods reduced drying time. However, the most effective was blanching, followed by PEF and US treatment, regardless of the drying technique. Non-thermal methods allowed for better preservation of bioactive compounds, such as vitamin C in the range of 8.2% to 22.5% or total carotenoid content in the range of 0.4% to 48%, in comparison to untreated dried material. Moreover, PEF-treated red bell peppers exhibited superior antioxidant activity (higher of about 15.2–30.8%) when compared to untreated dried samples, whereas sonication decreased the free radical scavenging potential by ca. 10%. In most cases, the pretreatment influenced the physical properties, such as porosity, color, or rehydration properties. Samples subjected to PEF and US treatment and dried by using a microwave-assisted method exhibited a significantly higher porosity of 2–4 folds in comparison to untreated material; this result was also confirmed by visual inspection of microtomography scans. Among tested methods, blanched samples had the most similar optical properties to untreated materials; however non-thermally treated bell peppers exhibited the highest saturation of the color. 相似文献
92.
This paper concerns the extension complexity of the Minimum Spanning Tree problem on a complete graph with nodes. The best known lower bound is the trivial bound, , the best known upper bound is the extended formulation size (Wong 1980, Martin 1991). We give a nondeterministic communication protocol with cost for the support of the spanning tree slack matrix. 相似文献
93.
Tsujimoto M Yamamoto T Delfanazari K Nakayama R Kitamura T Sawamura M Kashiwagi T Minami H Tachiki M Kadowaki K Klemm RA 《Physical review letters》2012,108(10):107006
Continuous, coherent subterahertz radiation arises when a dc voltage is applied across a stack of the many intrinsic Josephson junctions in a Bi2Sr2CaCu2O(8+δ) single crystal. The active junctions produce an equal number of I-V characteristic branches. Each branch radiates at a slightly tunable frequency obeying the Josephson relation. The overall output is broadly tunable and nearly independent of heating effects and internal cavity frequencies. Amplification by a surrounding external cavity to allow for the development of a useful high-power source is proposed. 相似文献
94.
Didia Coelho Gra?a Pierre Lescuyer Lorella Clerici Yury O. Tsybin Ralf Hartmer Markus Meyer Kaveh Samii Denis F. Hochstrasser Alexander Scherl 《Journal of the American Society for Mass Spectrometry》2012,23(10):1750-1756
A mass spectrometry-based assay combining the specificity of selected reaction monitoring and the protein ion activation capabilities of electron transfer dissociation was developed and employed for the rapid identification of hemoglobin variants from whole blood without previous proteolytic cleavage. The analysis was performed in a robust ion trap mass spectrometer operating at nominal mass accuracy and resolution. Subtle differences in globin sequences, resulting with mass shifts of about one Da, can be unambiguously identified. These results suggest that mass spectrometry analysis of entire proteins using electron transfer dissociation can be employed on clinical samples in a workflow compatible with diagnostic applications. 相似文献
95.
We prove that there is a constant c>0 depending only on M≥1 and μ≥0 such that
òyy+a |g(t)| dt 3 exp(-c/(ad)), ad ? (0,p],\int_y^{y+a}{ \bigl|g(t)\bigr| \, dt} \geq \exp \bigl(-c/(a\delta)\bigr), \quad a\delta \in (0,\pi], 相似文献
96.
We have performed molecular dynamics simulations to obtain internal energy and pressure of helium–neon and helium–krypton mixtures at different densities using accurate recently two-body ab initio potentials supplemented by quantum corrections following the Feynman–Hibbs approach. The significance of this work is that the three-body expression of Wang and Sadus [22] was used to improve prediction of the pressures and internal energies of helium + krypton and helium + neon mixtures without requiring an expensive three-body calculation. Our results show a good agreement with the corresponding experimental data. 相似文献
97.
Application of a nanostructured sensor based on graphene‐ and ethyl 2‐(4‐ferrocenyl[1,2,3]triazol‐1‐yl)acetate‐modified carbon paste electrode for determination of methyldopa in the presence of phenylephrine and guaifenesin 下载免费PDF全文
Hadi Beitollahi Kaveh Movlaee Mohammad Reza Ganjali Parviz Norouzi Rahman Hosseinzadeh 《应用有机金属化学》2018,32(4)
We introduce a new method to determine methyldopa without the interference of phenylephrine and guaifenesin. For this purpose, a carbon paste electrode was modified with graphene and ethyl 2‐(4‐ferrocenyl[1,2,3]triazol‐1‐yl)acetate. According to electrochemical studies, oxidation current of methyldopa on the surface of the modified electrode increased and shifted towards negative potentials. This modified electrode demonstrated two linear ranges of 0.4–30.0 μM and 30.0–500.0 μM with a detection limit of 0.08 μM. No change was observed in the sensitivity of the modified electrode towards methyldopa in the presence of phenylephrine and guaifenesin, which enables the simultaneous or independent measurement of the three moieties. The efficiency of the proposed modified electrode was evaluated through the determination of these substances in real samples. 相似文献
98.
Zinc chloride anhydrous has been used as an efficient and new catalyst for conversion of ketones and aldehydes to corresponding gem‐dihydroperoxides by aqueous hydrogen peroxide (30%) in room temperature with excellent yields and notable reaction times. 相似文献
99.
Matrices associated with symmetric and regular structures can be arranged into certain block patterns known as Canonical forms. Using such forms, the decomposition of structural matrices into block diagonal forms, is considerably simplified. In this paper the main canonical forms are reviewed; and symmetric/regular structural configurations that can be explained with such forms are investigated. The invariant subspaces are formulated and the closed form solutions for the block-diagonalized stiffness matrices are provided in each case. Utility and robustness of the canonical forms in the analysis of structures exhibiting decomposable matrix patterns are demonstrated by numerous examples. Furthermore, a numerical method is proposed to extend the computational advantages of the matrix canonical forms to other nonconforming regular structures. 相似文献
100.
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