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101.
Edward A. Karakhanov Anton L. Maximov Anna V. Zolotukhina Nadezhda Yatmanova Edward Rosenberg 《应用有机金属化学》2015,29(11):777-784
A series of Pd–Ag mixed‐metal nanocatalysts were prepared by reduction of Pd–Ag salts in the presence of poly(propylene imine) dendrimers, which were covalently bound to the surface of a silica polyamine composite, BP‐1 (polyallylamine covalently bound to a silanized amorphous silica gel). Three different Pd‐to‐Ag ratios were evaluated (50:50, catalyst 1 ; 40:60, catalyst 2 ; 60:40, catalyst 3 ) with the goal of determining how the amount of Ag effects selectivity, rate and conversion in the selective reduction of alkynes, such as phenylacetylene and 1‐ or 4‐octyne, to the corresponding alkenes. Conditions for the catalysis are reported where there is improved selectivity without a serious reduction in rate when compared with the analogous Pd‐only catalysts. Catalyst 2 worked best for phenylacetylene and catalyst 3 worked best for the octynes. The catalysts could be reused seven times without loss of activity. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
102.
Tatyana Kovshova Nadezhda Osipova Anna Alekseeva Julia Malinovskaya Alexey Belov Andrey Budko Galina Pavlova Olga Maksimenko Shakti Nagpal Svenja Braner Harshvardhan Modh Vadim Balabanyan Matthias G. Wacker Svetlana Gelperina 《Molecules (Basel, Switzerland)》2021,26(4)
Targeted delivery of doxorubicin still poses a challenge with regards to the quantities reaching the target site as well as the specificity of the uptake. In the present approach, two colloidal nanocarrier systems, NanoCore-6.4 and NanoCore-7.4, loaded with doxorubicin and characterized by different drug release behaviors were evaluated in vitro and in vivo. The nanoparticles utilize a specific surface design to modulate the lipid corona by attracting blood-borne apolipoproteins involved in the endogenous transport of chylomicrons across the blood–brain barrier. When applying this strategy, the fine balance between drug release and carrier accumulation is responsible for targeted delivery. Drug release experiments in an aqueous medium resulted in a difference in drug release of approximately 20%, while a 10% difference was found in human serum. This difference affected the partitioning of doxorubicin in human blood and was reflected by the outcome of the pharmacokinetic study in rats. For the fast-releasing formulation NanoCore-6.4, the AUC0→1h was significantly lower (2999.1 ng × h/mL) than the one of NanoCore-7.4 (3589.5 ng × h/mL). A compartmental analysis using the physiologically-based nanocarrier biopharmaceutics model indicated a significant difference in the release behavior and targeting capability. A fraction of approximately 7.310–7.615% of NanoCore-7.4 was available for drug targeting, while for NanoCore-6.4 only 5.740–6.057% of the injected doxorubicin was accumulated. Although the targeting capabilities indicate bioequivalent behavior, they provide evidence for the quality-by-design approach followed in formulation development. 相似文献
103.
104.
Some methods of training radial basis neural networks in solving the Navier‐Stokes equations
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Bakhtgerey Sinchev Saulet Erbulatovna Sibanbayeva Axulu Mukhambetkaliyevna Mukhanova Assel Nurgulzhanovna Nurgulzhanova Nurgali Sabyrovich Zaurbekov Kairat Sovetovish Imanbayev Nadezhda Lvovna Gagarina Lyazzat Kemerbekovna Baibolova 《国际流体数值方法杂志》2018,86(10):625-636
The purpose of this research is to analyze the application of neural networks and specific features of training radial basis functions for solving 2‐dimensional Navier‐Stokes equations. The authors developed an algorithm for solving hydrodynamic equations with representation of their solution by the method of weighted residuals upon the general neural network approximation throughout the entire computational domain. The article deals with testing of the developed algorithm through solving the 2‐dimensional Navier‐Stokes equations. Artificial neural networks are widely used for solving problems of mathematical physics; however, their use for modeling of hydrodynamic problems is very limited. At the same time, the problem of hydrodynamic modeling can be solved through neural network modeling, and our study demonstrates an example of its solution. The choice of neural networks based on radial basis functions is due to the ease of implementation and organization of the training process, the accuracy of the approximations, and smoothness of solutions. Radial basis neural networks in the solution of differential equations in partial derivatives allow obtaining a sufficiently accurate solution with a relatively small size of the neural network model. The authors propose to consider the neural network as an approximation of the unknown solution of the equation. The Gaussian distribution is used as the activation function. 相似文献
105.
Mesomorphic properties and structures of two mix-substituted lipophilic phthalocyanine derivatives of the A3B type, with a different ratio of electron-donating (hexadecyloxy-) and electron-withdrawing (Cl-) substituents on the isoindol fragments ‘A’ and ‘B’, correspondingly, were studied by polarising optical microscopy, differential scanning calorimetry and small-angle X-ray scattering. Both compounds display columnar mesophases, and the type of organisation of the columns in the mesomorphic state was found to strongly depend on the number of peripheral chlorine substituents in the molecule. The di-chloro-substituted phthalocyanine forms a solid pasty lamellar phase at room temperature, which on heating undergoes successive transitions to two large-lattice columnar mesophases (2D-Colh and 3D-MCol) arising from the aggregation of several phthalocyanine-containing piles. On the contrary, aggregation of columns does not occur for the tetra-chloro-substituted phthalocyanine, which forms a nematic columnar mesophase of single phthalocyanine piles (1D-NCol). While the di-chloro-compound partly crystallises on cooling, the nematic phase of the tetra-chloro-compound freezes at room temperature. The reasons for this different self-organisation behaviour are not yet fully understood, but some hints may be deduced from the proposed supramolecular models. 相似文献
106.
107.
Facile Separation,Spectroscopic Identification,and Electrochemical Properties of Higher Trifluoromethylated Derivatives of [70]Fullerene
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Maria P. Kosaya Alexey V. Rybalchenko Dr. Natalia S. Lukonina Olga N. Mazaleva Dr. Ilya N. Ioffe Dr. Vitaliy Yu. Markov Prof. Dr. Sergey I. Troyanov Prof. Dr. Lev N. Sidorov Dr. Nadezhda B. Tamm Dr. Alexey A. Goryunkov 《化学:亚洲杂志》2018,13(15):1920-1931
We survey the structure and electronic properties of the family of higher trifluoromethylated C70(CF3)n molecules with n=14, 16, 18, and 20. Twenty‐two available compounds, of which thirteen are newly obtained and characterized, demonstrate the broad diversity of π‐system topologies, which enabled us to study the interplay between the CF3 addition pattern and the electronic properties. UV/Vis spectroscopic and cyclic voltammetric studies demonstrate the importance of the exact addition pattern rather than the plain number of addends. Of particular interest is the skew pentagonal pyramid (SPP) addition pattern, which enables formation of closed‐shell cyclopentadienyl anions C70(CF3)n? 1 ? through CF3 detachment upon electron transfer. A detailed study of the process is presented for a SPP‐C70(CF3)16 where potentiostatic electrolysis at the second reduction potential gives C70(CF3)15? oxidizable to a persistent C70(CF3)15· radical. Together with the literature data for the lower C70(CF3)n compounds with n=2–12, the present results show good correlation between the experimental boundary level positions and the DFT predictions. The compounds turn out to be electron acceptor molecular semiconductors with experimental LUMO energies and HOMO–LUMO gaps within the ranges of ?4.3 to ?3.7 eV and 1.6 to 3.3 eV, respectively, depending on the shape of the conjugated fragments. The HOMO levels fall within the range of ?5.6 to ?6.9 eV and show linear correlation with the number of addends. 相似文献
108.
Radhakrishnan Srivedavyasasri Miriah B. White Tatyana S. Kustova Nadezhda G. Gemejiyeva Charles L. Cantrell 《Natural product research》2018,32(1):14-17
Salvia aethiopis is a perennial plant native to Eurasia and known by the common names Mediterranean sage or African sage. This plant has been used in Iranian medicine as a carminative and tonic. The ethanolic extract of aerial part of S. aethiopis exhibited moderate to weak activity towards delta and kappa opioid receptors (46.3 and 45.3% displacement, respectively). Chromatographic purification of the ethanolic extract on silica gel column led to isolation of one new: 3α-hydroxy-8α-acetoxy-13,14,15,16-tetranorlabdan-12-oic acid (I) and three known compounds: sesquiterpene spathulenol (II), β-sitosterol (III) and β-sitosterol-3-O-glucoside (IV). The structures of all isolated compounds were elucidated by their NMR (1D and 2D) and MS spectral data. All the fractions and isolated compounds were tested for cannabinoid and opioid receptor binding assays. 相似文献
109.
Troyanov SI Goryunkov AA Tamm NB Markov VY Ioffe IN Sidorov LN 《Dalton transactions (Cambridge, England : 2003)》2008,(19):2627-2632
A series of novel mixed C60Fn(CF3)m compounds has been produced by trifluoromethylation of C60F18 with CF3I in ampoules at 380-420 degrees C. Two of these compounds, C60F18(CF3)6 and C60F16(CF3)6, have been characterized by X-ray crystallography, which has revealed addition of six CF3 groups to the C3v-C60F18 for the former and replacement/elimination of two outermost F atoms in the latter. Quantum chemical calculations have been employed to predict the most stable possible isomers of C60F16/18(CF3)6 in order to rationalize the experimental results. 相似文献
110.
Igor B. Sivaev Nadezhda Yu. Kulikova Maxim V. Vichuzhanin Zoya A. Starikova Vladimir I. Bregadze 《Journal of organometallic chemistry》2008,693(3):519-525
Practical method of synthesis of the 1,4-dioxane derivative of the closo-dodecaborate anion was developed. The cleavage of the dioxonium ring in [B12H11O(CH2CH2)2O]− with acetylenic alcohols gave rise to the preparation of closo-dodecaborate derivatives with terminal acetylene group. These compounds can be introduced into click reactions with phenylazide leading to the corresponding triazoles. The structures of (Bu4N)[B12H11O(CH2CH2)2O] and (Bu4N)2[B12H11(OCH2CH2)2OCH2CCH] · 0.5HOCH2CCH were determined by single-crystal X-ray diffraction. 相似文献