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31.
T. Umecky T. Takamuku T. Aida T. Makino T. Aizawa M. Kanakubo 《Journal of solution chemistry》2014,43(9-10):1539-1549
2H and 17O NMR relaxation times, T 1(2H) and T 1(17O), and 2H NMR chemical shifts, δ(2H), in CO2-saturated CD3OD and C2D5OD solutions were measured at 313.2 K over the pressure range up to ~6 MPa. The rotational correlation times, τ r, of the CD and OD axes within CD3OD and C2D5OD molecules and the CO axis within the CO2 molecule were determined from T 1(2H) and T 1(17O), and the magnetic susceptibility-corrected chemical shifts, δ corr, were derived from δ(2H). The differences in τ r and δ corr observed between the two alcohol systems: τ r and δ corr of OD in C2D5OD, decreased rapidly with increasing CO2 concentration, while those of OD in CD3OD remained almost unchanged at mole fractions of CO2, \( x_{\text CO_{2}} \) , lower than ~0.25 and then slightly decreased at higher \( x_{\text CO_{2}} \) . The hydrogen bonding structure in C2D5OD was found to be gradually broken down by CO2 dissolution. On the other hand, in CD3OD, it has been revealed that the hydrogen bonding structure can persist at \( x_{\text CO_{2}} \) < ~0.25 but then collapses at higher \( x_{\text CO_{2}} \) . 相似文献
32.
el-Ansary AL Abdel-Fattah HM Abdel-Kader NS 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,79(3):522-528
The Schiff bases of N(2)O(2) dibasic ligands, H(2)La and H(2)Lb are prepared by the condensation of ethylenediamine (a) and trimethylenediamine (b) with 6-formyl-7-hydroxy-5-methoxy-2-methylbenzopyran-4-one. Also tetra basic ligands, H(4)La and H(4)Lb are prepared by the condensation of aliphatic amines (a) and (b) with 6-formyl-5,7-dihydroxy-2-methylbenzopyran-4-one. New complexes of H(4)La and H(4)Lb with metal ions Mn(II), Ni(II) and Cu(II) are synthesized, in addition Mn(II) complexes with ligands H(2)La and H(2)Lb are also synthesized. Elemental and thermal analyses, infrared, ultraviolet-visible as well as conductivity and magnetic susceptibility measurements are used to elucidate the structure of the newly prepared metal complexes. The structures of copper(II) complexes are also assigned based upon ESR spectra study. All the complexes separated with the stoichiometric ratio (1:1) (M:L) except Mn-H(4)La and Mn-H(4)Lb with (2:1) (M:L) molar ratio. In metal chelates of the type 1:1 (M:L), the Schiff bases behave as a dinegative N(2)O(2) tetradentate ligands. Moreover in 2:1 (M:L) complexes, the Schiff base molecules act as mono negative bidentate ligand and binuclear complex is then formed. The Schiff bases were assayed by the disc diffusion method for antibacterial activity against Staphylococcus aureus and Escherichia coli. The antifungal activity of the Schiff bases was also evaluated against the fungi Aspergillus flavus and Candida albicans. 相似文献
33.
Moyoko Tomiyasu Noriko Aida Yoshihiro Watanabe Kana Mori Kazuo Endo Kouki Kusakiri Jeff Kershaw Takayuki Obata Hitoshi Osaka 《Magnetic resonance imaging》2012
Background and Purpose
Influenza viral infection, which results in central nervous system dysfunction, is a major cause of acute encephalopathy (AE). The purpose of this study was to investigate the changes in the concentrations of brain metabolites in children with AE using single-voxel magnetic resonance spectroscopy (MRS) and to provide diagnostic information about the relationship between the symptoms of AE and metabolite concentrations.Materials and Methods
The subjects were 10 children (mean age: 6.2 years; range: 1–13) with AE caused by the novel influenza A virus responsible for the 2009 influenza pandemic. The serial MRS data (TE/TR=30/5000 ms, 3 T) acquired from the basal ganglia (BG) and centrum semiovale (CS) of each patient were categorized into three periods: (1) initial neurological symptom presentation and the start of treatment (n= 10), (2) short-term follow-up (n= 9) and (3) long-term follow-up (n= 3). As controls, the magnetic resonance (MR) spectra of eight age-matched children were also investigated.Results
In both regions, the concentrations of the major metabolites (N-acetylaspartate, creatine, choline, myo-inositol, glutamate/glutamine complex and glutamate) only showed minor fluctuations between the three periods. On the other hand, higher levels of taurine (Tau) were observed in the BG during the second period (P=.005), and increased levels of glucose were observed in the CS during the first (P=.005) and second (P=.036) periods.Conclusions
Serial monitoring of brain metabolite changes was carried out with a clinical MR system. The concentrations of major metabolites only displayed very minor fluctuations in response to mild H1N1-related AE. However, a higher Tau concentration was found to be associated with neurological symptoms. Further studies are required to improve our understanding of the detailed activity of Tau in AE. 相似文献34.
The living polymerization of methyl methacrylate with aluminium porphyrin ( 1 ) proceeded dramatically rapidly at room temperature in the presence of sterically crowded organoaluminium compounds such as methylaluminium ortho-substituted diphenolates ( 3a − 3g ), bis(triphenylmethanolate) ( 4a ), and triphenylaluminium, where undesired reaction between the growing species and the Lewis acids was sterically suppressed. On the basis of this Lewis acid - assisted high-speed living polymerization, various monomers such as ethyl, propyl, butyl, and dodecyl methacrylates, methacrylonitrile, and 1,2-epoxypropane were polymerized very rapidly with the aluminium porphyrin - Lewis acid systems. 相似文献
35.
This paper reports the important effects of frequency-locking in an electro-optical bistable system with long delay. The mechanism of the locking behaviour is discussed from the viewpoint of power spectrum and the linear eigen modes of the system. 相似文献
36.
Aida Toma 《Rendiconti del Circolo Matematico di Palermo》2009,58(1):29-40
This paper proves a new integral representation theorem for powers of elements in locally m-convex algebras. It is shown that the conditions handled in this theorem are satisfied for any sequentially complete locally
m-convex Q-algebra. Various applications of this result concerning the spectrum, the spectral radius or the numerical radius are given.
相似文献
37.
38.
39.
Aida Toma 《Comptes Rendus Mathematique》2013,351(7-8):311-316
We consider new classes of estimators and test statistics for models satisfying linear constraints with unknown parameter. These procedures are based on minimization of divergences through duality techniques. We prove that, for various divergences, the new approach provides robust estimation and test procedures, unlike the empirical likelihood method. We give general results using the influence function approach, which we exemplify in detail in the case of the Cressie–Read divergences. It is found that the Hellinger distance is one of the divergences that leads to robust procedures. 相似文献
40.
A cyclic dimer of chiral saddle-shaped porphyrin with p-xylylene linkers, upon interaction with mandelic acid, showed an enhanced circular dichroism activity, which was more than 7 times as large as that of a monomeric reference. 相似文献