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991.
A novel crystalline coordination polymer containing Ce3+ and bis(4‐nitrophenyl) phosphate (L), CeL3, was synthesized and its unique transmetalation selectivities toward Yb3+ and Lu3+ in the lanthanide series were evaluated. The relatively large difference in transmetalation selectivity between the neighboring Tm3+ and Yb3+ species is noteworthy because the reactivities of heavy lanthanides are generally considerably similar. The structural strain of the polymeric framework is likely responsible for this unusual trend. Powder X‐ray diffraction analysis indicated that, in the cases of only Yb3+ and Lu3+, large differences in their ionic sizes compared to that of Ce3+ in the parent framework may induce a structural strain after solid solution formation, while cleavage of the relatively weak Ce?O bond allows the formation of new Yb?O and Lu?O bonds with the incoming Yb3+ and Lu3+, respectively. Structural phase transitions likely caused by the heterogeneous nucleation of the Yb‐ (or Lu‐) type phase were also observed. 相似文献
992.
Mostafa Abdelrahman Nur Aeni Ariyanti Yuji Sawada Fumitada Tsuji Sho Hirata Tran Thi Minh Hang Mami Okamoto Yutaka Yamada Hiroshi Tsugawa Masami Yokota Hirai Masayoshi Shigyo 《Molecules (Basel, Switzerland)》2020,25(22)
Shallot landraces and varieties are considered an important genetic resource for Allium breeding due to their high contents of several functional metabolites. Aiming to provide new genetic materials for the development of a novel bulb onion cultivar derived from intraspecific hybrids with useful agronomic traits from shallots, the metabolic profiles in the bulbs of 8 Indonesian shallot landraces and 7 short-day and 3 long-day bulb onion cultivars were established using LC–Q-TOF-MS/MS. Principal component analysis, partial least squares discriminant analysis, and dendrogram clustering analysis showed two major groups; group I contained all shallot landraces and group II contained all bulb onion cultivars, indicating that shallots exhibited a distinct metabolic profile in comparison with bulb onions. Variable importance in the projection and Spearman’s rank correlation indicated that free and conjugated amino acids, flavonoids (especially metabolites having flavonol aglycone), and anthocyanins, as well as organic acids, were among the top metabolite variables that were highly associated with shallot landraces. The absolute quantification of 21 amino acids using conventional HPLC analysis showed high contents in shallots rather than in bulb onions. The present study indicated that shallots reprogrammed their metabolism toward a high accumulation of amino acids and flavonoids as an adaptive mechanism in extremely hot tropical environments. 相似文献
993.
Ryo Ohtani Kenichi Kawano Masanao Kinoshita Saeko Yanaka Hikaru Watanabe Kenji Hirai Shiroh Futaki Nobuaki Matsumori Hiroshi Uji‐i Masaaki Ohba Koichi Kato Shinya Hayami 《Angewandte Chemie (International ed. in English)》2020,59(41):17931-17937
Cell membranes contain lateral systems that consist of various lipid compositions and actin cytoskeleton, providing two‐dimensional (2D) platforms for chemical reactions. However, such complex 2D environments have not yet been used as a synthetic platform for artificial 2D nanomaterials. Herein, we demonstrate the direct synthesis of 2D coordination polymers (CPs) at the liquid‐cell interface of the plasma membrane of living cells. The coordination‐driven self‐assembly of networking metal complex lipids produces cyanide‐bridged CP layers with metal ions, enabling “pseudo‐membrane jackets” that produce long‐lived micro‐domains with a size of 1–5 μm. The resultant artificial and visible phase separation systems remain stable even in the absence of actin skeletons in cells. Moreover, we show the cell application of the jackets by demonstrating the enhancement of cellular calcium response to ATP. 相似文献
994.
995.
Abstract The chain transfer constant of the polymethyl methacrylate radical for N,N-dimethylaniline was determined in two solvents, benzene and dimethyl phthalate. Plots were made using1/Pn=kt°Rp/kp 2[M]2η + CS1 [S1]/[M] + CS2 [S2]/[M] +CM where η=viscosity of monomer-solvents mixture, kt°=rate coefficient of termination when η=1 cP, S1=benzene or dimethyl phthalate, S2=N,N-dimethylaniline, and other symbols have their usual meanings. The plots agreed well for the two solvents. If the plots were made without considering the viscosity term, two separate lines resulted for the two solvents. Thus it is essential to consider the viscosity of the polymerizing system in the analysis of chain transfer reactions when the termination reaction is diffusion-controlled and the viscosities of the monomer and solvent differ markedly. 相似文献
996.
Tsuyoshi Michinobu Masami Bito Miki Tanimura Yoshihiro Katayama Eiji Masai Masaya Nakamura 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(6):564-570
Copolymers of L-lactic acid (LA) and 2-pyrone-4,6-dicarboxylic acid (PDC), a chemically stable metabolic intermediate of lignin, were prepared by dehydrated polycondensation based on stepwise oligomerization followed by post-polymerization in vacuo. When the polymerization was performed in the presence of methanesulfonic acid as a catalyst, the molecular weights of the resulting copolymers were sufficiently high. Furthermore, expansion of the polymeric surface area was found to be an important factor in facilitating dehydration and thereby producing high molecular weight polymers. PDC feed ratio significantly affected the molecular weight because of the different polymerization capability from LA. Relationship between the PDC feed ratio and the molecular weight of the resulting polyesters was for the first time demonstrated quantitatively. The obtained copolymers were characterized by 1H- and 13C-NMR, IR, and thermal analysis. The high molecular weight copolymers possessed the higher decomposition temperatures than PLLA and their fusible temperature ranges were reasonably expanded. 相似文献
997.
Dielectric control of the topology of an exciton wavefunction is proposed and investigated theoretically. As we have shown in a previous paper, we can change the topology of an exciton wavefunction in a nanotube structure by controlling the length and radius of the nanotube. This nature yields a new device which utilizes the topology of an exciton wavefunction, however, its control via the structural parameters does not suit it to device applications. We found that the in-situ control can be achieved by changing the ambient dielectric constants of the nanotube structure and we calculated the transition condition of the topology of an exciton wavefunction. 相似文献
998.
In this paper we address a topological approach to multiflow (multicommodity flow) problems in directed networks. Given a terminal weight μ, we define a metrized polyhedral complex, called the directed tight span Tμ, and prove that the dual of the μ-weighted maximum multiflow problem reduces to a facility location problem on Tμ. Also, in case where the network is Eulerian, it further reduces to a facility location problem on the tropical polytope spanned by μ. By utilizing this duality, we establish the classifications of terminal weights admitting a combinatorial min–max relation (i) for every network and (ii) for every Eulerian network. Our result includes the Lomonosov–Frank theorem for directed free multiflows and Ibaraki–Karzanov–Nagamochi’s directed multiflow locking theorem as special cases. 相似文献
999.
A novel phase-shifting digital holographic method for estimation of inner surface profiles of tubes is proposed. For surface
contouring, a two-wavelength method using injection-current-induced wavelength changes of a laser diode is used. To obtain
inner surface information on a tube, a cone-shaped mirror is set inside the tube. Speckle noise occurring in the reconstructed
phase difference image is effectively suppressed by an adaptive filtering technique consisting of exponential averaging and
masking filtering processes. Distribution of optical path length in the experimental alignment is calculated and well explains
the experimental results. It is shown that the calculation of optical path length by a simple model can remove the distortion
of profiles occurring in the experimental results and enable the estimation of the inner surface profile of an aluminum tube. 相似文献
1000.
Hisaaki Takeshima Kotaro Satoh Masami Kamigaito 《Journal of polymer science. Part A, Polymer chemistry》2020,58(1):91-100
A series of bio-based vinylphenols or hydroxystyrenes is prepared by simple decarboxylation of various naturally occurring cinnamic acids such as o-, m-, and p-coumaric; caffeic; ferulic; and sinapinic acids, which possess hydroxy groups and other substituents at different positions on the aromatic ring. After protection of the phenolic moieties with trialkylsilyl groups, reversible addition–fragmentation chain-transfer polymerization is accomplished with cumyl dithiobenzoate to afford various bio-based hydroxyl-protected polystyrenes with controlled molecular weights and narrow molecular weight distributions. Subsequent deprotection of the silyl groups under mild conditions results in a series of well-defined functionalized polystyrenes possessing different numbers (mono-, di-, tri-) of hydroxy groups at different positions (o, m, p). The obtained functionalized polystyrenes show unique thermal properties depending on the substituents, and those with phenol and catechol groups serve as reducing agents for silver ions. © 2019 Wiley Periodicals, Inc. J. Polym. Sci. 2020 , 58, 91–100 相似文献