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991.
992.
Dr. Marta Ruiz-Santaquiteria Prof. Beatriz M. Illescas Rana Abdelnabi Arnaud Boonen Alberto Mills Olaia Martí-Marí Dr. Sam Noppen Dr. Johan Neyts Dr. Dominique Schols Prof. Federico Gago Ana San-Félix María-José Camarasa Prof. Nazario Martín 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(41):10700-10710
Unprecedented 3D hexa-adducts of [60]fullerene peripherally decorated with twelve tryptophan (Trp) or tyrosine (Tyr) residues have been synthesized. Studies on the antiviral activity of these novel compounds against HIV and EV71 reveal that they are much more potent against HIV and equally active against EV71 than the previously described dendrimer prototypes AL-385 and AL-463 , which possess the same number of Trp/Tyr residues on the periphery but attached to a smaller and more flexible pentaerythritol core. These results demonstrate the relevance of the globular 3D presentation of the peripheral groups (Trp/Tyr) as well as the length of the spacer connecting them to the central core to interact with the viral envelopes, particularly in the case of HIV, and support the hypothesis that [60]fullerene can be an alternative and attractive biocompatible carbon-based scaffold for this type of highly symmetrical dendrimers. In addition, the functionalized fullerenes here described, which display twelve peripheral negatively charged indole moieties on their globular surface, define a new and versatile class of compounds with a promising potential in biomedical applications. 相似文献
993.
Cheri Anne M. Dingle Julius Federico M. Jecong Frederick C. Hila Ma. Elina Salvacion V. Ramo Neil Raymund D. Guillermo Magdaleno R. Vasquez Jr Vallerie Ann I. Samson 《X射线光谱测定》2019,48(5):513-521
Allanite is a common accessory mineral in igneous rocks that contains significant amounts of rare-earth elements (REEs), thorium (Th), and uranium (U). The presence of Th and U in the allanite exposes it to radiation resulting in radiation damage in its crystal structure and further leads to metamictization. Hence, allanite can be used as a natural analogue to assess the long-term radiation effects in materials for high-level nuclear waste disposal. It provides information on the effect of α-decay on the crystal structure including the stability and integrity of the material. In this study, the absorbed α-dose of allanite from Ombo, Palawan, Philippines, was estimated from the Th and U content and geological age of the mineral using X-ray fluorescence and gamma-ray spectrometry. The amount of Th and REE was measured to be around 1.37 and ~30.4 wt.%, respectively. Radiometric dating using gamma-ray spectrometry estimated the age of the allanite mineral to be around 24–35 million years. Having obtained the amount of radioactivity and the time of exposure, the corresponding absorbed α-dose was estimated to be at 2.84 × 1014 α-decays/mg. Results suggest that the allanite mineral studied has not accumulated significant radiation damage to cause amorphization and still exhibit a crystalline structure. This study may provide data on the properties of allanite or silicate matrices as part of the ongoing studies on silicate minerals as natural analogues. 相似文献
994.
Meccanica - The recovery of the stress gradient in finite elements problems is a widely discussed topic with many applications in the design process. The stress gradient is related to the second... 相似文献
995.
996.
Journal of Statistical Physics - The study of the phase ordering kinetics of the ferromagnetic one-dimensional Ising model dates back to 1963 (R. J. Glauber, J. Math. Phys. 4, 294) for non... 相似文献
997.
ABSTRACT High temperature is of paramount importance in high pressure science. One of the leading tools in this respect is the resistively heated diamond anvil cell (DAC), where the heat is provided by small heaters, positioned close to the diamond/gasket/sample region (internally heated DAC, IHDAC) or by wrapping the DAC body into bigger heaters (externally heated DAC, EHDAC). Although IHDACs can reach sample temperatures higher than 1000?K, they are difficult to handle and the heater/diamond/gasket/sample region may be affected by strong thermal gradients potentially hindering accurate temperature measurements. Here we present a novel EHDAC, which overcomes these issues by uniquely joining: (i) high mechanical precision for multi-Mbar, (ii) high temperature alloys for operating to 1000?K, (iii) membrane or screw driven, easily switchable between each other, (iv) operation into a vacuum chamber, (v) uniform temperature, (vi) facile handling, and (vii) possibility to add internal heaters for achieving even higher temperatures. 相似文献
998.
Laura Pistelli Rose Vanessa Bandeira Reidel Federico Parri Elisabetta Morelli Luisa Pistelli 《Natural product research》2019,33(1):143-147
The essential oil composition of three spontaneous species growing in an abandoned mining of Elba island was analyzed by GC–MS. A total of 194 compounds were identified representing 73.7–100% of the whole oil composition. The essential oils of Cistus salvifolius and Dittrichia viscosa from this site showed different profiles in comparison with those from not polluted area, where oxygenated sesquiterpenes were the main class. Volatiles from D. viscosa growing in ex-mining area presented 10-epi-γ-eudesmol and α-eudesmol as main compounds while β-caryophyllene and limonene were the main ones in not polluted area. Ambroxide and ambrial were the most important compounds in the essential oil from C. salvifolius harvested in polluted area while nonanal and tridecanal were the main compounds in control samples. Oxygenated monoterpenes were the most abundant class from both Lavandula stoechas samples, with fenchone and camphor as main compounds. 相似文献
999.
Carpinteri Alberto Accornero Federico 《Archive of Applied Mechanics (Ingenieur Archiv)》2019,89(11):2313-2320
Archive of Applied Mechanics - In this work, an historical overview concerning the theory of shell structures is presented. Early conjectures proposed by, among others, French, German, and Russian... 相似文献
1000.
Matthias Franke Florencia Marchini Prof. Dr. Norbert Jux Prof. Dr. Hans‐Peter Steinrück Dr. Ole Lytken Prof. Dr. Federico J. Williams 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(25):8520-8524
Demetalation of zinc 5,10,15,20‐tetraphenylporphyrin (ZnTPP) under acidic conditions and ion exchange with Cu2+ ions at neutral pH are both rapid reactions in the liquid medium. However, for ZnTPP monolayers adsorbed on a Au(111) surface exposed to aqueous solution, we find that, although ion exchange takes place rapidly as expected, demetalation does not occur, even at pH values as low as 0. Based on this, we conclude that metal center exchange on the surface does not proceed through a free‐base porphyrin as an intermediate. Furthermore, once formed, CuTPP is stable on the surface and the reverse exchange from CuTPP to ZnTPP in the presence of Zn2+ ions could not be achieved. The preference for copper is so strong that even an attempt to exchange adsorbed ZnTPP with Ni2+ ions in the presence of traces of Cu2+ yielded CuTPP rather than NiTPP. 相似文献