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711.
712.
Maximilian N. Kopylovich Kamran T. Mahmudov M. Fátima C. Guedes da Silva Luísa M.D.R.S. Martins Maxim L. Kuznetsov Telma F.S. Silva João J.R. Fraústo da Silva Armando J.L. Pombeiro 《Journal of Physical Organic Chemistry》2011,24(9):764-773
Trends between the Hammett's σp and related normal , inductive σI, resonance σR, negative and positive polar conjugation and Taft's σp° substituent constants and the distance, δN? H NMR chemical shift, oxidation potential (Ep/2°x, measured in this study by cyclic voltammetry (CV)) and thermodynamic parameters (pK, ΔG0, ΔH0 and ΔS0) of the dissociation process of unsubstituted 3‐(phenylhydrazo)pentane‐2,4‐dione (HL1) and its para‐substituted chloro (HL2), carboxy (HL3), fluoro (HL4) and nitro (HL5) derivatives were recognized. The best fits were found for σp and/or in the cases of , δN? H and Ep/2°x, showing the importance of resonance and conjugation effects in such properties, whereas for the above thermodynamic properties the inductive effects (σI) are dominant. HL2 exists in the hydrazo form in DMSO solution and in the solid state and contains an intramolecular H‐bond with the distance of 2.588(3) Å. It was also established that the dissociation process of HL1–5 is non‐spontaneous, endothermic and entropically unfavourable, and that the increase in the inductive effect (σI) of para‐substitutents (? H < ? Cl < ? COOH < ? F < ? NO2) leads to the corresponding growth of the distance and decrease of the pK and of the changes of Gibbs free energy, of enthalpy and of entropy for the HL1–5 acid dissociation process. The electrochemical behaviour of HL1–5 was interpreted using theoretical calculations at the DFT/HF hybrid level, namely in terms of HOMO and LUMO compositions, and of reactivities induced by anodic and cathodic electron‐transfers. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
713.
Quantum cryptography is the field of cryptography that explores the quantum properties of matter. Generally, it aims to develop primitives beyond the reach of classical cryptography and to improve existing classical implementations. Although much of the work in this field covers quantum key distribution (QKD), there have been some crucial steps towards the understanding and development of quantum oblivious transfer (QOT). One can show the similarity between the application structure of both QKD and QOT primitives. Just as QKD protocols allow quantum-safe communication, QOT protocols allow quantum-safe computation. However, the conditions under which QOT is fully quantum-safe have been subject to intense scrutiny and study. In this review article, we survey the work developed around the concept of oblivious transfer within theoretical quantum cryptography. We focus on some proposed protocols and their security requirements. We review the impossibility results that daunt this primitive and discuss several quantum security models under which it is possible to prove QOT security. 相似文献
714.
Ling Huang Armando Alcazar Magana Patricia A. Skinkis James Osborne Yanping L. Qian Michael C. Qian 《Molecules (Basel, Switzerland)》2022,27(14)
Grapevine red blotch disease (GRBD) has negative effects on grape development and impacts berry ripening. Abscisic acid (ABA) is a plant growth regulator involved in the initiation of berry ripening. Exogenous abscisic acid application was compared to an unsprayed control on GRBD-positive Pinot noir vines during two vintages, and the total monomeric anthocyanin, total phenolics, phenolic composition, and volatile profile were measured in wines. In addition, untargeted metabolites were profiled using high-resolution LC-MS/MS. Results showed that the wine composition varied by vintage year and was not consistent with ABA application. Wines from the ABA treatment had a lower total anthocyanin and total phenolic content in one year. The untargeted high-resolution LC-MS/MS analysis showed a higher abundance of phenolic compounds in ABA wines in 2019, but lower in 2018. The wine volatile compounds of ABA treatments varied by vintage. There were higher levels of free β-damascenone, β-ionone, nerol, and several fermentation-derived esters, acids, and alcohols in ABA wines, but these were not observed in 2019. Lower 3-isobutyl-2-methoxypyrazine (IBMP) was also observed in wines with ABA treatment in 2019. The results demonstrated that ABA application to the fruit zones did not consistently mitigate the adverse impacts of GRBD on Pinot noir wines. 相似文献
715.
Patrizio Vaiano Benito Carotenuto Marco Pisco Armando Ricciardi Giuseppe Quero Marco Consales Alessio Crescitelli Emanuela Esposito Andrea Cusano 《Laser \u0026amp; Photonics Reviews》2016,10(6):922-961
This review presents an overview of “Lab on Fiber” technologies and devices with special focus on the design and development of advanced fiber optic nanoprobes for biological applications. Depending on the specific location where functional materials at micro and nanoscale are integrated, “Lab on Fiber Technology” is classified into three main paradigms: Lab on Tip (where functional materials are integrated onto the optical fiber tip), Lab around Fiber (where functional materials are integrated on the outer surface of optical fibers), and Lab in Fiber (where functional materials are integrated within the holey structure of specialty optical fibers). This work reviews the strategies, the main achievements and related devices developed in the “Lab on Fiber” roadmap, discussing perspectives and challenges that lie ahead, with special focus on biological sensing applications.
716.
Dr. Haibo Wu Dr. Zhiyao Zheng Dr. Kaiheng Zhang Dr. Johan Kajanus Dr. Magnus J. Johansson Prof. Dr. Armando Córdova Prof. Dr. Jan-E. Bäckvall 《Angewandte Chemie (International ed. in English)》2023,62(50):e202314512
Classical Crabbé type SN2' substitutions of propargylic substrates has served as one of the standard methods for the synthesis of allenes. However, the stereospecific version of this transformation often requires either stoichiometric amounts of organocopper reagents or special functional groups on the substrates, and the chirality transfer efficiency is also capricious. Herein, we report a sustainable methodology for the synthesis of diverse 1,3-di and tri-substituted allenes by using a simple and cheap cellulose supported heterogeneous nanocopper catalyst (MCC-Amp-Cu(I/II)). This approach represents the first example of heterogeneous catalysis for the synthesis of chiral allenes. High yields and excellent enantiospecificity (up to 97 % yield, 99 % ee) were achieved for a wide range of di- and tri-substituted allenes bearing various functional groups. It is worth noting that the applied heterogeneous catalyst could be recycled at least 5 times without any reduced reactivity. To demonstrate the synthetic utility of the developed protocol, we have applied it to the total synthesis of several chiral allenic natural products. 相似文献