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991.
Vidura D. Thalangamaarachchige Nadeesha J. Silva Daniel K. Unruh Adelia J.A. Aquino Clemens Krempner 《Tetrahedron》2019,75(13):1861-1864
The synthesis, structures and spectroscopic properties of M(MeOCH2CH2OMe2Si)3CBH3 (M-1-BH3) and M(MeOCH2CH2OMe2Si)3SiBH3 (M-2-BH3) (M?=?Li, Na, K) derived from reactions of BH3 with the alkali metal zwitterions [M(MeOCH2CH2OMe2Si)3C] (M-1) and [M(MeOCH2CH2OMe2Si)3Si] (M-2) (M?=?Li, Na, K), resp., are reported. X-ray analysis and DFT calculations reveal discrete zwitterionic structures with the octahedral alkali metal cations rigidly locked and charge separated from the BH3 units via pendant donors groups. Solution experiments with the hydride acceptors B(C6F5)3 and [Ph3C]2[B12C12] indicate that Na-1-BH3 can donate hydrides to form cations of formula [Na(MeOCH2CH2OMe2Si)3CBH2]+. 相似文献
992.
The 2,5-diketopiperazine (DKP) moiety is a core feature of many natural products and medicinally relevant scaffolds. As part of our efforts directed towards a total synthesis of penicisulfuranol B, we have developed and report herein: (1) the preparation of an N-hydroxy diketopiperazine intermediate accessible via a molybdenum-mediated oxidation of a parent diketopiperazine, and (2) further synthetic studies leading to a novel spirocyclic dihydrobenzofuran-containing diketopiperazine. 相似文献
993.
Lirong Ma Xuanlin Yang Xiuzhong Yao Weiyu Weng 《Photochemistry and photobiology》2020,96(5):1088-1095
Hexyl aminolevulinate (HAL) is a lipophilic derivative of 5-aminolevulinic acid (5-ALA) and can induce more protoporphyrin IX (PpIX) formation and stronger fluorescence intensity (FI) than 5-ALA, which will greatly facilitate photodynamic diagnosis and therapy. The main drawback of HAL is its low solubility in neutral aqueous media. In this study, surfactants were used to increase HAL solubility in the cell culture medium and serum, followed by in vitro fluorescence formation measurement in human pancreatic cancer cells (SW1990) and in vivo fluorescence detection in tumor-bearing mice. The results showed that Tween 80 (TW80) and Kolliphor® HS 15 (HS15) increased the solubility of HAL in the selected media. Although TW80 and HS15 exhibited in vitro cytotoxicity at high concentrations (5 mg mL−1), they facilitated fluorescent signal formation at the early stage of cell incubation. When surfactants were used, the FI should be determined without the routine washing process because surfactant-containing culture medium caused the loss of synthesized PpIX during the washing process. When HAL dissolved in TW80 solution was injected intraperitoneally into pancreatic cancer-bearing mice at a dose of 50 mg kg−1, the tumors exhibited red fluorescence, which indicated that systemic administration of surfactant-solubilized HAL might be applicable for tumor fluorescence detection in vivo. 相似文献
994.
Bozhev I. V. Krupenin V. A. Presnov D. E. Tsiniaikin I. I. Dorofeev A. A. Trifonov A. S. 《Technical Physics》2020,65(5):832-838
Technical Physics - A non-destructive method of scanning probe microscopy for simultaneous measurements of the surface topography and electric field (charge, potential) distribution is... 相似文献
995.
ABSTRACT In this paper, we present a systematic roadmap for developing a robust and parallel multi-material reactive hydrodynamic solver that integrates historically stable algorithms with new and current modern methods to solve explosive system design problems. The Ghost Fluid Method and Riemann solvers were used to enforce appropriate interface boundary conditions. Improved performance in terms of computational work and convergence properties was achieved by modifying a local node sorting strategy that decouples ghost nodes, allowing us to set material boundary conditions via an explicit procedure, removing the need to solve a coupled system of equations numerically. The locality and explicit nature of the node sorting concept allows for greater levels of parallelism and lower computational cost when populating ghost nodes. Non-linear numerical issues endemic to the use of real Equations of State in hydro-codes were resolved by using more thermodynamically consistent forms allowing us to accurately resolve large density gradients associated with high energy detonation problems at material interfaces. Pre-computed volume tables were implemented adding to the robustness of the solver base. 相似文献
996.
ABSTRACTThe compound Ca3Co2O6 undergoes a transition into a spin-density wave (SDW) state near 24?K. Below ~10?K, this unstable SDW state coexists with a nearly- degenerate commensurate antiferromagnetic state as well as short-range magnetic order. Clear signatures of this strong magnetic disorder have been observed in the response of entropy to changing magnetic field and temperature. We performed a calorimetry study of Ca3Co2O6 and Ca3Co1.9Zn0.1O6 in order to compare their entropic responses at low temperature. Our results for Ca3Co2O6 reveal that ΔS(T, H)?≡?S(T, H)?S(T, H?=?0) increases as either temperature or magnetic field increase. In contrast, ΔS data for Ca3Co1.9Zn0.1O6 were relatively unresponsive to changes in temperature or field, suggesting that Zn substitution may reduce the low-temperature magnetic disorder observed in Ca3Co2O6. These results are discussed within the context of two cases (Ca3Co2O6 under applied pressure and Ca2.75R0.25Co2O6 (R?=?Dy, Lu)) in which a single magnetic ground state is stabilised. 相似文献
997.
998.
Fedotova J. A. Kharchanka A. A. Fedotov A. K. Chichkov M. V. Malinkovich M. D. Konakov A. O. Vorobyova S. A. Kasiuk J. V. Gumiennik U. E. Kula M. Mitura-Nowak M. Maximenko A. A. Przewoźnik J. Kapusta Cz. 《Physics of the Solid State》2020,62(2):368-377
Physics of the Solid State - Electrodeposition of cobalt on monolayer graphene synthesized by chemical vapor deposition produces Co–CoO/graphene composite structures, which is accompanied by... 相似文献
999.
Physics of the Solid State - Based on a general analytical approach supported with results of model numerical calculations, the possibility of developing periodic layered impurity structures formed... 相似文献
1000.
Umirzakov B. E. Tashmukhamedova D. A. Gulyamova S. T. Allayarova G. Kh. 《Technical Physics》2020,65(5):795-798
Technical Physics - It is shown that a film consisting of the Mo–O, Mo–Ba–O, and Ba–O compounds is formed in the ion-implanted layer upon implantation of MoO3 with the Ba+... 相似文献