排序方式: 共有14条查询结果,搜索用时 15 毫秒
1.
Michelina Soccio Lara Finelli Nadia Lotti Valentina Siracusa Tiberio A. Ezquerra Andrea Munari 《Journal of Polymer Science.Polymer Physics》2007,45(13):1694-1703
Poly(butylene naphthalate) (PBN), poly(diethylene naphthalate) (PDEN), and poly(thiodiethylene naphthalate) (PTDEN) were synthesized and characterized in terms of chemical structure and molecular weight. The polyesters were examined by TGA, DSC, and DMTA. All the polymers showed a good thermal stability, even though depending on chemical structure. At room temperature they appeared as semicrystalline materials; the effect of the introduction along the PBN polymer chain of ether oxygen atoms or sulfur ones was a lowering in the Tg value, a decrement of Tm, and a decrease of the crystallization rate. Changing in chemical structure also affects the main α absorption associated with the glass transition which moves to lower temperature and whose energetic requirements decrease. The results were explained as due to the presence of highly flexible C? S? C or C? O? C bonds in the polymeric chain. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1694–1703, 2007 相似文献
2.
Catauro Michelina Dal Poggetto Giovanni Risoluti Roberta Vecchio Ciprioti Stefano 《Journal of Thermal Analysis and Calorimetry》2020,142(5):1767-1774
Journal of Thermal Analysis and Calorimetry - Chemical stability, anticorrosive properties and photocatalytic activity of titanium dioxide (TiO2) are among the most important characteristics for... 相似文献
3.
Michelina Soccio Nadia Lotti Lara Finelli Massimo Gazzano Andrea Munari 《Journal of Polymer Science.Polymer Physics》2010,48(17):1901-1910
Poly(glycolic acid) (PGA) and a series of novel random copolymers of PGA containing 2‐hydroxyisobutyrric acid (PGAPHIB) (HIB unit content from 1.5 to 7.4 mol %) were synthesized and characterized in terms of chemical structure and molecular weight. Afterward, the polyesters were examined by thermogravimetric analysis, differential scanning calorimetry, and X‐ray diffraction techniques. The copolymers, which displayed a better thermal stability than PGA, at room temperature appeared as semicrystalline materials: the main effect of copolymerization was a lowering in the amount of crystallinity and a decrease of the melting temperature with respect to homopolymer PGA. Baur's equation described well the Tm‐composition data. X‐ray diffraction measurements allowed the identification of the PGA crystalline structure in all cases. After melt quenching, semicrystalline samples were obtained with the exception of PGAPHIB7.4 copolymer. The introduction of HIB units decreased the crystallization rate compared with pure PGA. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1901–1910, 2010 相似文献
4.
We present a form of the Mean Value Theorem (MVT) for a continuous function f between metric spaces, connecting it with the possibility to choose the relation of f in a homeomorphic way. We also compare our formulation of the MVT with the classic one when the metric spaces are open subsets of Banach spaces. As a consequence, we derive a version of the Mean Value Propriety for measure spaces that also possesses a compatible metric structure. 相似文献
5.
Sergey Milikisyants Francesco Scarpelli Michelina G. Finiguerra Marcellus Ubbink Martina Huber 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2009,201(1):48-56
Methods to determine distances between paramagnetic metal centers and radicals are scarce. This is unfortunate because paramagnetic metal centers are frequent in biological systems and so far have not been employed much as distance markers. Successful pulse sequences that directly target the dipolar interactions cannot be applied to paramagnetic metal centers with fast relaxation rates and large g-anisotropy, if no echos can be detected and the excitation bandwidth is not sufficient to cover a sufficiently large part of the spectrum. The RIDME method Kulik et al. (2002) [20] circumvents this problem by making use of the T1-induced spin-flip of the transition-metal ion. Designed to measure distance between such a fast relaxing metal center and a radical, it suffers from a dead time problem. We show that this is severe because the anisotropy of the metal center broadens the dipolar curves, which therefore, only can be analyzed if the full curve is known. Here, we introduce five-pulse RIDME (5p-RIDME) that is intrinsically dead-time free. Proper functioning of the sequence is demonstrated on a nitroxide biradical. The distance between a low-spin Fe(III) center and a spin label in spin-labeled cytochrome f shows the complete dipolar trace of a transition-metal ion center and a spin label, yielding the distance expected from the structure. 相似文献
6.
Catauro Michelina Naviglio Daniele Risoluti Roberta Vecchio Ciprioti Stefano 《Journal of Thermal Analysis and Calorimetry》2018,133(2):1085-1092
Journal of Thermal Analysis and Calorimetry - Imbalance of the iron level in the body causes several diseases. In particular, the low level of iron, during pregnancy, is responsible for the iron... 相似文献
7.
Ignazio Blanco Alberta Latteri Gianluca Cicala Antonio DAngelo Veronica Viola Vincenzo Arconati Michelina Catauro 《Molecules (Basel, Switzerland)》2022,27(3)
This paper aims to synthesize, via the sol–gel method, a biomaterial usable in the medical field. Here, the silica-PEG-quercetin system was evaluated in relation to the different concentrations of PEG (0, 6, 12, 24, 50 wt%) and quercetin (0, 5, 10, 15 wt%), respectively. In addition, Fourier Transform-Infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and Kirby–Bauer analyses were performed. FT-IR was used to evaluate the hybrid formation and the influence of both PEG and Quercetin in the hybrid synthesized materials, SEM was used to evaluate the morphological properties, while the Kirby–Bauer test was used to understand the ability of the materials to inhibit the growth of the assayed bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, and Staphylococcus aureus). 相似文献
8.
Marika Fiorentino Simona Piccolella Claudia Gravina Adriano Stinca Assunta Esposito Michelina Catauro Severina Pacifico 《Molecules (Basel, Switzerland)》2023,28(1)
Wild edible plants, once consumed in times of famine or for health purposes, today represent an interesting dietary supplement, aimed at enriching local dishes and/or formulating healthy nutraceutical products. In fact, the broad content of different, and diversely bioactive, specialized metabolites therein suggests new scenarios of use which, in order to be as functional as possible, must maximize the bioactivity of these compounds while preserving their chemistry. In this context, based on a recent investigation on the metabolic profile of the organs of Calendula arvensis that highlighted that florets are abundant in flavonol glycosides and triterpene saponins, the freeze-drying encapsulation of their alcoholic extract (FE) into maltodextrin (MD) was investigated. FE-MD chemical composition was evaluated using Fourier Transform InfraRed spectroscopy (FTIR), while ultra-high performance liquid chromatography coupled with high-resolution tandem mass spectrometry (UHPLC-HRMS/MS) techniques were employed to unravel FE compound preservation also during in vitro simulated digestion. The establishment of H-bonds between FE compounds and MD hydroxyl groups was in line with FE-MD biocompatibility in Caco-2 cells, while in vitro digestion mostly affected structural integrity and/or diversity. Flavonol compounds underwent deglycosylation and demethylation, while deacylation, beyond oxidation, involved triterpene saponins, which massively preserve their aglycone core. 相似文献
9.
Dr. Linda Del Bino Dr. Ilaria Calloni Dr. Davide Oldrini Dr. Maria Michelina Raso Dr. Rossella Cuffaro Dr. Ana Ardá Prof. Jeroen D. C. Codée Prof. Jesús Jiménez-Barbero Dr. Roberto Adamo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(71):16277-16287
Group B Streptococcus serotypes Ia and Ib capsular polysaccharides are key targets for vaccine development. In spite of their immunospecifity these polysaccharides share high structural similarity. Both are composed of the same monosaccharide residues and differ only in the connection of the Neu5Acα2-3Gal side chain to the GlcNAc unit, which is a β1-4 linkage in serotype Ia and a β1-3 linkage in serotype Ib. The development of efficient regioselective routes for GlcNAcβ1-3[Glcβ1-4]Gal synthons is described, which give access to different group B Streptococcus (GBS) Ia and Ib repeating unit frameshifts. These glycans were used to probe the conformation and molecular dynamics of the two polysaccharides, highlighting the different presentation of the protruding Neu5Acα2-3Gal moieties on the polysaccharide backbones and a higher flexibility of Ib polymer relative to Ia, which can impact epitope exposure. 相似文献
10.
Abdelhakim Bouyahya Aicha El Allam Ikrame Zeouk Douae Taha Gokhan Zengin Bey Hing Goh Michelina Catauro Domenico Montesano Nasreddine El Omari 《Molecules (Basel, Switzerland)》2022,27(1)
Grifolin is a volatile compound contained in essential oils of several medicinal plants. Several studies show that this substance has been the subject of numerous pharmacological investigations, which have yielded interesting results. Grifolin demonstrated beneficial effects for health via its multiple pharmacological activities. It has anti-microbial properties against bacteria, fungi, and parasites. In addition, grifolin exhibited remarkable anti-cancer effects on different human cancer cells. The anticancer action of this molecule is related to its ability to act at cellular and molecular levels on different checkpoints controlling the signaling pathways of human cancer cell lines. Grifolin can induce apoptosis, cell cycle arrest, autophagy, and senescence in these cells. Despite its major pharmacological properties, grifolin has only been investigated in vitro and in vivo. Therefore, further investigations concerning pharmacodynamic and pharmacokinetic tests are required for any possible pharmaceutical application of this substance. Moreover, toxicological tests and other investigations involving humans as a study model are required to validate the safety and clinical applications of grifolin. 相似文献