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1.
Etémé Armand Sylvin Tabi Conrad Bertand Beyala Ateba Jean Félix Ekobena Fouda Henry Paul Mohamadou Alidou Crépin Kofané Timoléon 《Nonlinear dynamics》2021,105(1):785-795
Nonlinear Dynamics - The fluctuation of ions concentration across the cell membrane of neuron can generate a time varying electromagnetic field. Thus, memristors are used to realize the coupling... 相似文献
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Is PdII‐Promoted σ‐Bond Metathesis Mechanism Operative for the PdPEPPSI Complex‐Catalyzed Amination of Chlorobenzene with Aniline? Experiment and Theory 下载免费PDF全文
Feiqun Wang Lei Zhu Yunfei Zhou Prof. Xiaoguang Bao Prof. Henry F. Schaefer III 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(10):4153-4161
Reduction of the Pd?PEPPSI precatalyst to a Pd0 species is generally thought to be essential to drive Buchwald–Hartwig amination reactions through the well‐ documented Pd0/PdII catalytic cycle and little attention has been paid to other possible mechanisms. Considered here is the Pd?PEPPSI‐catalyzed aryl amination of chlorobenzene with aniline. A neat reaction system was used in new experiments, from which the potentially reductive roles of the solvent and labile ligand of the PEPPSI complex in leading to Pd0 species are ruled out. Computational results demonstrate that anilido‐containing PdII intermediates involving σ‐bond metathesis in pathways leading to the diphenylamine product have relatively low barriers. Such pathways are more favorable energetically than the corresponding reductive elimination reactions resulting in Pd0 species and other putative routes, such as the PdII/PdIV mechanism, single electron transfer mechanism, and halide atom transfer mechanism. In some special cases, if reactants/additives are inadequate to reduce a PdII precatalyst, a PdII‐involved σ‐bond metathesis mechanism might be feasible to drive the Buchwald–Hartwig amination reactions. 相似文献
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Electrochemical Vicinal Difluorination of Alkenes: Scalable and Amenable to Electron-Rich Substrates
Sayad Doobary Alexi T. Sedikides Henry P. Caldora Dr. Darren L. Poole Dr. Alastair J. J. Lennox 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(3):1171-1176
Fluorinated alkyl groups are important motifs in bioactive compounds, positively influencing pharmacokinetics, potency and conformation. The oxidative difluorination of alkenes represents an important strategy for their preparation, yet current methods are limited in their alkene-types and tolerance of electron-rich, readily oxidized functionalities, as well as in their safety and scalability. Herein, we report a method for the difluorination of a number of unactivated alkene-types that is tolerant of electron-rich functionality, giving products that are otherwise unattainable. Key to success is the electrochemical generation of a hypervalent iodine mediator using an “ex-cell” approach, which avoids oxidative substrate decomposition. The more sustainable conditions give good to excellent yields in up to decagram scales. 相似文献
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Indermeet Kohli Taylor L. Braunberger Amanda F. Nahhas Fatima N. Mirza Mohsen Mokhtari Alexis B. Lyons Nikiforos Kollias Eduardo Ruvolo Henry W. Lim Iltefat H. Hamzavi 《Photochemistry and photobiology》2020,96(1):208-214
Human skin is exposed to visible light (VL; 400–700 nm) and long-wavelength ultraviolet A1 (UVA1) radiation (370–400 nm) after the application of organic broad-spectrum sunscreens. The biologic effects of these wavelengths have been demonstrated; however, a dose–response has not been investigated. Ten subjects with Fitzpatrick skin phototype IV-VI were enrolled. Subjects were irradiated with 2 light sources (80–480 J cm−2): one comprising VL with less than 0.5% UVA1 (VL+UVA1) and the other pure VL. Skin responses were evaluated for 2 weeks using clinical and spectroscopic assessments. 4-mm punch biopsies were obtained from nonirradiated skin and sites irradiated with 480 J cm−2 of VL+UVA1 and pure VL 24 h after irradiation. Clinical and spectroscopic assessments demonstrated a robust response at VL+UVA1 sites compared with pure VL. Histology findings demonstrated a statistically significant increase in the marker of inflammation (P < 0.05) and proliferation (P < 0.05) at the irradiated sites compared with nonirradiated control. Threshold doses of VL+UVA1 resulting in biologic responses were calculated. Results indicate that approximately 2 h of sun exposure, which equates to VL+UVA1 dose (~400 J cm−2), is capable of inducing inflammation, immediate erythema and delayed tanning. These findings reinforce the need of photoprotection beyond the UV range. 相似文献
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Henry Robinson Steven A. Oatley James E. Rowedder Pawel Slade Dr. Simon J. F. Macdonald Dr. Stephen P. Argent Prof. Dr. Jonathan D. Hirst Thomas McInally Prof. Dr. Christopher J. Moody 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(34):7678-7684
A late-stage functionalization of the aromatic ring in amino acid derivatives is described. The key step is a copper-catalysed diversification of a boronate ester by amination (Chan–Lam reaction) that can be carried out on a complex β-aryl-β-amino acid scaffold. This not only considerably extends the substrate scope of amination partners, but also delivers an array of potent and selective integrin inhibitors as potential treatment agents of idiopathic pulmonary fibrosis (IPF). This versatile chemical strategy, which is amenable to high-throughput-array protocols, allows the installation of pharmaceutically valuable heteroaromatic fragments at a late stage by direct coupling to NH heterocycles, leading to compounds with drug-like attributes. It thus constitutes a useful addition to the medicinal chemist's repertoire. 相似文献
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Henry Dring David Kreutzer Christoph Ritter Andreas Hilgeroth 《Molecules (Basel, Switzerland)》2021,26(1)
Despite the development of targeted therapies in cancer, the problem of multidrug resistance (MDR) is still unsolved. Most patients with metastatic cancer die from MDR. Transmembrane efflux pumps as the main cause of MDR have been addressed by developed inhibitors, but early inhibitors of the most prominent and longest known efflux pump P-glycoprotein (P-gp) were disappointing. Those inhibitors have been used without knowledge about the expression of P-gp by the treated tumor. Therefore the use of inhibitors of transmembrane efflux pumps in clinical settings is reconsidered as a promising strategy in the case of the respective efflux pump expression. We discovered novel symmetric inhibitors of the symmetric efflux pump MRP4 encoded by the ABCC4 gene. MRP4 is involved in many kinds of cancer with resistance to anticancer drugs. All compounds showed better activities than the best known MRP4 inhibitor MK571 in an MRP4-overexpressing cell line assay, and the activities could be related to the various substitution patterns of aromatic residues within the symmetric molecular framework. One of the best compounds was demonstrated to overcome the MRP4-mediated resistance in the cell line model to restore the anticancer drug sensitivity as a proof of concept. 相似文献
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Neville Murphy Dr. William J. Tipping Henry J. Braddick Dr. Liam T. Wilson Prof. Nicholas C. O. Tomkinson Prof. Karen Faulds Prof. Duncan Graham Dr. Pau Farràs 《Angewandte Chemie (International ed. in English)》2023,62(48):e202311530
Multiplex optical detection in live cells is challenging due to overlapping signals and poor signal-to-noise associated with some chemical reporters. To address this, the application of spectral phasor analysis to stimulated Raman scattering (SRS) microscopy for unmixing three bioorthogonal Raman probes within cells is reported. Triplex detection of a metallacarborane using the B−H stretch at 2480–2650 cm−1, together with a bis-alkyne and deuterated fatty acid can be achieved within the cell-silent region of the Raman spectrum. When coupled to imaging in the high-wavenumber region of the cellular Raman spectrum, nine discrete regions of interest can be spectrally unmixed from the hyperspectral SRS dataset, demonstrating a new capability in the toolkit of multiplexed Raman imaging of live cells. 相似文献
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Cover Picture: Velocity of a Molecule Evaporated from a Water Nanodroplet: Maxwell–Boltzmann Statistics versus Non‐Ergodic Events (Angew. Chem. Int. Ed. 49/2015) 下载免费PDF全文
Assist. Prof. Dr. Hassan Abdoul‐Carime Francis Berthias Dr. Linda Feketeová Dr. Mathieu Marciante Dr. Florent Calvo Dr. Valérian Forquet Prof. Dr. Henry Chermette Dr. Bernadette Farizon Prof. Dr. Michel Farizon Prof. Dr. Tilmann D. Märk 《Angewandte Chemie (International ed. in English)》2015,54(49):14587-14587