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901.
Dorota Kostrzewa Agnieszka Dobrzyska-Inger Barbara Mazurek Marcin Kostrzewa 《Molecules (Basel, Switzerland)》2022,27(7)
Supercritical carbon dioxide extraction was used to extract carotenoids from dry paprika Capsicum annuum. Studies regarding the effect of process parameters, including pressure (25–45 MPa), temperature (40–60 °C), and time (10–110 min), were carried out using response surface methodology. It was found that under optimal conditions (pressure of 45 MPa, temperature of 50 °C, and time of 74 min), the extract yield was 10.05%, and the total content of carotenoids in the extract was 4.21%, in good agreement with the predicted values (10.24% and 4.24%, respectively). Composition analysis showed that paprika extract mainly consisted of linoleic acid. There was no significant difference between the fatty acid content of the extracts obtained by SC-CO2 extraction and n-hexane Soxhlet extraction. For functional purposes, the effect of storage conditions and time on the quality of paprika extract was also specified. 相似文献
902.
Emília Valena Ferreira de Arago Luca Mancini Noelia Faginas-Lago Marzio Rosi Dimitrios Skouteris Fernando Pirani 《Molecules (Basel, Switzerland)》2022,27(7)
The reaction between the cyano radical CN and cyanoacetylene molecule HCN is of great interest in different astronomical fields, from star-forming regions to planetary atmospheres. In this work, we present a new synergistic theoretical approach for the derivation of the rate coefficient for gas phase neutral-neutral reactions. Statistic RRKM calculations on the Potential Energy Surface are coupled with a semiempirical analysis of the initial bimolecular interaction. The value of the rate coefficient for the HCN + CN → H + NCCCCN reaction obtained with this method is compared with previous theoretical and experimental investigations, showing strengths and weaknesses of the new presented approach. 相似文献
903.
Svetlana I. Dorovskikh Denis E. Tryakhov Darya D. Klyamer Alexander S. Sukhikh Irina V. Mirzaeva Natalia B. Morozova Tamara V. Basova 《Molecules (Basel, Switzerland)》2022,27(7)
To search for new suitable Pd precursors for MOCVD/ALD processes, the extended series of fluorinated palladium complexes [Pd(CH3CXCHCO(R))2] with β-diketone [tfa−1,1,1-trifluoro-2,4-pentanedionato (1); pfpa−5,5,6,6,6-pentafluoro-2,4-hexanedionato (3); hfba−5,5,6,6,7,7,7-heptafluoro-2,4-heptanedionato (5)] and β-iminoketone [i-tfa−1,1,1-trifluoro-2-imino-4-pentanonato (2); i-pfpa−5,5,6,6,6-pentafluoro-2-imino-4-hexanonato (4); i-hfba-5,5,6,6,7,7,7-heptafluoro-2-imino-4-heptanonato (6)] ligands were synthesized with 70–80% yields and characterized by a set of experimental (SXRD, XRD, IR, NMR spectroscopy, TG) and theoretical (DFT, Hirshfeld surface analysis) methods. Solutions of Pd β-diketonates contained both cis and trans isomers, while only trans isomers were detected in the solutions of Pd β-iminoketonates. The molecules 2–6 and new polymorphs of complexes 3 and 5 were arranged preferentially in stacks, and the distance between molecules in the stack generally increased with elongation of the fluorine chain in ligands. The H…F contacts were the main ones involved in the formation of packages of molecules 1–2, and C…F, F…F, NH…F contacts appeared in the structures of complexes 4–6. The stability of complexes and their polymorphs in the crystal phases were estimated from DFT calculations. The TG data showed that the volatility differences between Pd β-iminoketonates and Pd β-diketonates were minimized with the elongation of the fluorine chain in the ligands. 相似文献
904.
Morgane Rosendale Jonathan Daniel Frdric Castet Paolo Pagano Jean-Baptiste Verlhac Mireille Blanchard-Desce 《Molecules (Basel, Switzerland)》2022,27(7)
Molecular-based Fluorescent Organic Nanoparticles (FONs) are versatile light-emitting nano-tools whose properties can be rationally addressed by bottom-up molecular engineering. A challenging property to gain control over is the interaction of the FONs’ surface with biological systems. Indeed, most types of nanoparticles tend to interact with biological membranes. To address this limitation, we recently reported on two-photon (2P) absorbing, red to near infrared (NIR) emitting quadrupolar extended dyes built from a benzothiadiazole core and diphenylamino endgroups that yield spontaneously stealth FONs. In this paper, we expand our understanding of the structure-property relationship between the dye structure and the FONs 2P absorption response, fluorescence and stealthiness by characterizing a dye-related series of FONs. We observe that increasing the strength of the donor end-groups or of the core acceptor in the quadrupolar (D-π-A-π-D) dye structure allows for the tuning of optical properties, notably red-shifting both the emission (from red to NIR) and 2P absorption spectra while inducing a decrease in their fluorescence quantum yield. Thanks to their strong 1P and 2P absorption, all FONs whose median size varies between 11 and 28 nm exhibit giant 1P (106 M−1.cm−1) and 2P (104 GM) brightness values. Interestingly, all FONs were found to be non-toxic, exhibit stealth behaviour, and show vanishing non-specific interactions with cell membranes. We postulate that the strong hydrophobic character and the rigidity of the FONs building blocks are crucial to controlling the stealth nano-bio interface. 相似文献
905.
Henghui Zhang Xiaoli Wang Dongliang He Dongliang Zou Runzhu Zhao Huifang Wang Shuying Li Yongping Xu Buhailiqiemu Abudureheman 《Molecules (Basel, Switzerland)》2022,27(1)
In the present work, the extraction process of total flavonoids (TFs) from X. sorbifolia flowers by ultrasound-assisted extraction was optimized under the response surface methodology (RSM) on the basis of single-factor experiments. The optimal extraction conditions were as follows: ethanol concentration of 80%, solid–liquid ratio of 1:37 (g/mL), temperature of 84 °C, and extraction time of 1 h. Under the optimized conditions, the extraction yield of the TFs was 3.956 ± 0.04%. The radical scavenging capacities of TFs against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) were much greater than that of rutin. The results of antibacterial experiments indicated that the TFs displayed strong inhibitory activities on E. coli, S. aureus and Bacillus subtilis. Therefore, X. sorbifolia flowers can be used as a novel source of natural flavonoids, and the TFs have potential applications as natural antioxidants or antibacterial agents in the food and pharmaceutical industries. 相似文献
906.
907.
908.
聚四氟乙烯材料表面激光改性与刻蚀 总被引:1,自引:0,他引:1
利用波长为248 nm的准分子激光束在不同激光能量密度下照射聚四氟乙烯(PTFE)材料的表面,并用扫描电镜(SEM)、X射线光电子能谱(XPS)、拉曼(Raman)光谱等手段对激光处理前后样品的表面形貌、化学成分和结构进行测量和分析,进而对激光与聚四氟乙烯相互作用的机理进行了研究。实验结果表明,激光辐照使聚四氟乙烯表面产生去氟效应,导致表面碳化、分子链的交联以及含氧基团的产生,随着激光能量密度的增加,C=C双键逐渐形成。这些结构的变化可以导致表面硬度和粘结性增强。激光能量密度的大小对照射后样品表面的物理性质和化学结构有着重要的影响,它是聚合物表面激光改性和烧蚀的关键因素。 相似文献
909.
目前的虹膜识别都是采用在图像上提取特征点,并将特征点编码为固定长度的特征数据用于匹配的方式。这种方式使虹膜识别系统易受攻击。为了进一步提高虹膜识别系统的安全性和识别速度,提出了一种基于灰度曲面匹配的虹膜识别方法。该方法抛弃了特征提取和编码等传统操作,在特征分析的基础上直接利用了灰度曲面匹配的思想,首先对两幅图像中的像素灰度做差,得到灰度差曲面,然后求出该灰度差曲面的方差。将此方差作为衡量两个虹膜特征曲面之间距离的依据,并据此判定两个虹膜是否来自同一只眼睛。在给定阈值为40的前提下,正确识别率为96.89%,识别时间为53.2 ms。实验结果证明,该方法识别准确率高,识别速度快。 相似文献
910.
根据湄洲湾海域2005年丰、平、枯三个水期的海水监测及2005年9月的湄洲湾表层沉积物监测数据对湄洲湾的环境质量进行评价。结果显示,湄洲湾海域水质综合指数(WQI)全年平均为0.69,除了F1站位枯水期为1.04,轻度污染,其余的均小于1.0,全年综合评价为清洁,但受气候及水文条件的影响,丰水期和枯水期有两个站位呈富营养化状态;表层沉积物综合质量指标平均值为0.52,综合评价为清洁,但铜、砷、镉的单因子污染指数平均值介于0.5~1.0之间,说明表层沉积物已被这三个因子玷污。 相似文献