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101.
Amarender Manchoju Renaud Zelli Gang Wang Carla Eymard Adrian Oo Mona Nemer Michel Prvost Baek Kim Yvan Guindon 《Molecules (Basel, Switzerland)》2022,27(2)
The design of novel nucleoside triphosphate (NTP) analogues bearing an all-carbon quaternary center at C2′ or C3′ is described. The construction of this all-carbon stereogenic center involves the use of an intramoleculer photoredox-catalyzed reaction. The nucleoside analogues (NA) hydroxyl functional group at C2′ was generated by diastereoselective epoxidation. In addition, highly enantioselective and diastereoselective Mukaiyama aldol reactions, diastereoselective N-glycosylations and regioselective triphosphorylation reactions were employed to synthesize the novel NTPs. Two of these compounds are inhibitors of the RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2, the causal virus of COVID-19. 相似文献
102.
103.
The COVID-19 pandemic has raised many questions on how to manage an epidemiological and economic crisis around the world. Since the beginning of the COVID-19 pandemic, scientists and policy makers have been asking how effective lockdowns are in preventing and controlling the spread of the virus. In the absence of vaccines, the regulators lacked any plausible alternatives. Nevertheless, after the introduction of vaccinations, to what extent the conclusions of these analyses are still valid should be considered. In this paper, we present a study on the effect of vaccinations within the dynamic stochastic general equilibrium model with an agent-based epidemic component. Thus, we validated the results regarding the need to use lockdowns as an efficient tool for preventing and controlling epidemics that were obtained in November 2020. 相似文献
104.
Many mushroom species are consumed as food, while significant numbers are also utilised medicinally. Mushrooms are rich in nutrients and bioactive compounds. A growing body of in vitro, in vivo, and human research has revealed their therapeutic potentials, which include such properties as anti-pathogenic, antioxidant, anti-inflammatory, immunomodulatory, gut microbiota enhancement, and angiotensin-converting enzyme 2 specificity. The uses of medicinal mushrooms (MMs) as extracts in nutraceuticals and other functional food and health products are burgeoning. COVID-19 presents an opportunity to consider how, and if, specific MM compounds might be utilised therapeutically to mitigate associated risk factors, reduce disease severity, and support recovery. As vaccines become a mainstay, MMs may have the potential as an adjunct therapy to enhance immunity. In the context of COVID-19, this review explores current research about MMs to identify the key properties claimed to confer health benefits. Considered also are barriers or limitations that may impact general recommendations on MMs as therapy. It is contended that the extraction method used to isolate bioactive compounds must be a primary consideration for efficacious targeting of physiological endpoints. Mushrooms commonly available for culinary use and obtainable as a dietary supplement for medicinal purposes are included in this review. Specific properties related to these mushrooms have been considered due to their potential protective and mediating effects on human exposure to the SARS CoV-2 virus and the ensuing COVID-19 disease processes. 相似文献
105.
Federica Sodano Elena Gazzano Roberta Fruttero Loretta Lazzarato 《Molecules (Basel, Switzerland)》2022,27(7)
Nitric oxide is a ubiquitous signaling radical that influences critical body functions. Its importance in the cardiovascular system and the innate immune response to bacterial and viral infections has been extensively investigated. The overproduction of NO is an early component of viral infections, including those affecting the respiratory tract. The production of high levels of NO is due to the overexpression of NO biosynthesis by inducible NO synthase (iNOS), which is involved in viral clearance. The development of NO-based antiviral therapies, particularly gaseous NO inhalation and NO-donors, has proven to be an excellent antiviral therapeutic strategy. The aim of this review is to systematically examine the multiple research studies that have been carried out to elucidate the role of NO in viral infections and to comprehensively describe the NO-based antiviral strategies that have been developed thus far. Particular attention has been paid to the potential mechanisms of NO and its clinical use in the prevention and therapy of COVID-19. 相似文献
106.
107.
M. L. Keshtov A. L. Rusanov N. M. Belomoina A. S. Peregudov E. R. Tkhakakhov 《Russian Chemical Bulletin》2005,54(8):1939-1941
New hexaarylbenzene-containing di- and tetrafluoroarenes were prepared by the Diels—Alder reactions of 1,4-bis(1-oxo-2,4,5-triphenylcyclopentadien-3-yl)benzene
with 4-fluoro-4′-(phenylethynyl)- and 4-fluoro-4′-(4-fluorophenylethynyl)benzophenone, respectively.
__________
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1881–1883, August, 2005. 相似文献
108.
Two solid phase transitions of [Cd(H2O)6](BF4)2 occurring on heating at TC2=183.3 K and TC1=325.3 K, with 2 K and 5 K hysteresis, respectively, were detected by differential scanning calorimetry (DSC). High value of entropy changes indicated large orientational disorder of the high temperature and intermediate phase. Nuclear magnetic resonance (1H NMR and 19F NMR) relaxation measurements revealed that the phase transitions at TC1 and TC2 were associated with a drastic and small change, respectively, of the both spin-lattice relaxation times: T1(1H) and T1(19F). These relaxation processes were connected with the “tumbling” motions of the [Cd(H2O)6]2+, reorientational motions of the H2O ligands, and with the iso- and anisotropic reorientation of the BF4− anions. The cross-relaxation effect was observed in phase III. The line width and the second moment of the 1H and 19F NMR line measurements revealed that the H2O reorientate in all three phases of the title compound. On heating the onset of the reorientation of 3 H2O in the [Cd(H2O)6]+2, around the three-fold symmetry axis of these octahedron, causes the isotropic reorientation of the whole cation. The BF4− reorientate isotropically in the phases I and II, but in the phase III they perform slow reorientation only about three- or two-fold axes. A small distortion in the structure of BF4− as well as of [Cd(H2O)6]2+ is postulated. The temperature dependence of the bandwidth of the O-H stretching mode measured by Fourier transform middle infrared spectroscopy (FT-MIR) indicated that the activation energy for the reorientation of the H2O did not change much at the TC2 phase transition. 相似文献
109.
The knowledge of hydrocarbon/water phase equilibria is important in the design and operation of equipment for petroleum transport and refining and petrochemical plants. The presence of water in a hydrocarbon mixture can affect the product quality and damage the operation equipment due to corrosion and formation of gas hydrates. Tracing the concentration of hydrocarbons in aqueous media is also important for technical purposes like preventing oil spills and for ecological concerns such as predicting the fate of these organic pollutants in the environment. 相似文献
110.
Catherine Bessada Aydar Rakhmatullin Anne-Laure Rollet Didier Zanghi 《Journal of fluorine chemistry》2009,130(1):45-52
In situ high temperature nuclear magnetic resonance in molten fluoride mixtures gives some structural picture of the complexes existing in the melt, i.e. of their nature and relative proportion. Thanks to the development of a laser heating system associated with a close crucible in boron nitride, we can describe experimentally the evolution of these complexes from the anions and the cations point of view. By 19F NMR, we have shown the existence of three kinds of fluorine atoms depending on the composition: free fluorine like in pure LiF (non-bonded), bridging fluorine in melts rich in LnF3 in addition with terminal fluorine singly bonded to one rare earth. Data obtained by NMR spectroscopy are also combined with EXAFS measurements, again thanks to a specific development of the sample holder adapted with molten fluorides and high temperature. This study is a part of our systematic investigation of the different Alk-LnF3 systems by NMR and EXAFS spectroscopy. 相似文献