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1.
Fumiko Fujisaki Sachi Hiromatsu Yumiko Matsumura Aki Fukami Nobuhiro Kashige Fumio Miake Kunihiro Sumoto 《Journal of heterocyclic chemistry》2013,50(2):417-424
In connection with our studies on antibacterial active compounds in the class of new oxazolidinones against Gram‐positive (Staphylococcus aureus) and Gram‐negative (Escherichia coli) strains, some molecular modifications were attempted. In this study, molecular modifications of 4‐aminomethyloxazolidin‐2‐ones ( 3a ) to the corresponding 4‐acylaminomethyloxazolidin‐2‐one derivatives ( 3c–d ) and preparations of the represented twin‐drug type molecules ( 10–14 ) were investigated. Some additional 4‐dialkylaminomethyloxazolidin‐2‐ones ( 2 ) were also synthesized. The synthesized compounds were evaluated for antibacterial activity with Gram‐positive (S. aureus) and Gram‐negative (E. coli) strains. 相似文献
2.
Charles J. K. Batty Mark D. Blake Sachi Srivastava 《Integral Equations and Operator Theory》2003,45(2):125-154
Let
f : \mathbbR+ ? \mathbbC f : \mathbb{R}_{+} \longrightarrow \mathbb{C} be an exponentially bounded, measurable function. We introduce a growth bound z(f) \zeta(f) which measures the extent to which f f can be approximated by holomorphic functions. This growth bound is related to the location of the domain of holomorphy of the Laplace transform of f f far from the real axis. The denition extends to vector and operator-valued cases. For a C0 C_{0} -semigroup T T of operators, z(T) \zeta(T) is closely related to the critical growth bound of T T . 相似文献
3.
The concise enantioselective total synthesis of C(2)-asymmetrical (-)-deoxocuscohygrine and (-)-dihydrocuscohygrine are described. Double-diastereoselective additions of normal Grignard reagent to bis(1,3-oxazolidine) have been deployed to construct chiral diamine fragments as a key step. 相似文献
4.
This paper provides analytical chemical information on selected new molecular entities (NMEs) which are drugs that have recently been approved by the FDA. These are the antiretroviral drugs, atazanavir, indinavir and emtricitabine, the antibacterial gemifloxacin, rosuvastatine which is a cholesterol-lowing drug, the anti-cancer drug gefitinib and aprepitant for neurological disorders. Electrospray ionisation-quadrupole ion trap mass spectrometry (ESI-MSn) was employed to generate tandem mass spectrometric (MS2) data of the drugs studied and structural assignments of product ions were supported by quadrupole time-of-flight mass spectrometry (QToF-MS/MS). These fragmentation studies were then utilised in the development and validation of a specific and sensitive liquid chromatographic method (LC–ESI-MS2) to identify and determine these drugs at therapeutic concentration levels in serum after a single protein precipitation procedure with acetonitrile. In addition, this method was compared to the application of gas liquid chromatography-flame ionisation detection (GLC-FID) and differential pulse polarography (DPP) for the analysis of these NMEs in serum. 相似文献
5.
Leo W.Y. Yeung Yuichi Miyake Sachi Taniyasu Keerthi S. Guruge Nobuyoshi Yamashita 《Analytica chimica acta》2009,635(1):108-5513
The widespread occurrence and environmental persistence of perfluorinated compounds (PFCs) received worldwide attention recently. Exhaustive analysis of all fluorinated compounds in an environmental sample can be daunting because of the constraints in the availability of analytical standards and extraction methods. Combustion ion chromatographic technique for trace fluorine analysis was used to assess the concentrations of known PFCs (e.g., PFOS, PFOA) and total fluorine (TF) in the blood of wild rats collected from Japan. The technique was further validated using tissues from PFOA-exposed rats. Six PFCs (PFOS, PFOSA, PFUnDA, PFDA, PFNA, and PFOA) were detected in all of the wild rat blood samples. Concentrations of extractable organic fluorine (EOF) in fraction 1 (Fr1; MTBE extraction) of wild rats ranged 60.9-134 ng F mL−1, while those in fraction 2 (Fr2; hexane) were below LOQ (32 ng F mL−1); TF concentrations in the blood of wild rats ranged from 59.9-192 ng F mL−1. The contribution of known PFCs in EOF-Fr1 (MTBE) varied from 9% to 89% (56% on average), and known PFC concentrations in TF content were less than 25%. In contrast, TF concentrations in the blood of PFOA-exposed rats ranged from 46900 to 111000 ng F mL−1, with PFOA contributing over 90% of TF. A comparison of results from the samples analyzed in this study and the literature revealed three distinct groups with PFOA/known PFC and TF levels (i.e., wild rats and general population, occupationally exposed workers, and PFOA-exposed laboratory rats). The mass balance analysis of the different forms of fluorine in blood suggested the presence of other forms of organic fluorine in addition to known PFCs. 相似文献
6.
Naofumi Kozai Sachi Kawamura Tamotsu Kozaki Toshihiko Ohnuki Takahiro Sato Fumitaka Esaka 《Journal of solid state chemistry》2007,180(8):2279-2289
Fe2+-montmorillonite with Fe2+ ions occupying cation exchange sites is an ideal transformation product in bentonite buffer material. In our previous study on preparation and characterization of Fe2+-montmorillonite, the montmorillonite sample that adsorbed Fe2+ ions on almost all of the cation exchange sites was prepared using a FeCl2 solution under an inert gas condition [N. Kozai, Y. Adachi, S. Kawamura, K. Inada, T. Kozaki, S. Sato, H. Ohashi, T. Ohnuki, T. Banba, J. Nucl. Sci. Technol. 38 (2001) 1141]. In view of the unstable nature of iron(II) chemical species, this study attempted to determine the potential contaminant iron chemical species in the sample. Nondestructive elemental analysis revealed that a small amount of chloride ions remained dispersed throughout the clay particles. The chloride ion retention may be due to the adsorption of FeCl+ ion pairs in the initial FeCl2 solution and the subsequent containment of the Cl− ions that are dissociated from the FeCl+ ion pairs during excess salt removal treatment. Two explanations are advanced for the second process: the slow release of the remaining Cl− ions from the collapsed interlayer of the montmorillonite, and the transformation of a minor fraction of the remaining FeCl+ ion pairs to iron(III) hydroxide chloride complexes having low solubility. 相似文献
7.
Sachi Morinaga Takashi Nishiyama Takashi Kajiwara Kunihito Nagayama 《Applied Physics A: Materials Science & Processing》2010,101(4):743-746
A compositionally graded thin film of FeSi2 was fabricated by a gravity-assisted pulsed laser ablation (GAPLA) system. By this method, a compositionally graded structure
was successfully produced under a gravity field of 5400 G. We demonstrate that the atomic fraction of Fe, the heavier component
of the thin film measured by scanning electron microscope/energy dispersive X-ray (SEM-EDX), showed increasing spatial distribution
with the direction of gravity. We found that optimal laser fluence exists to give a thin film having the largest possible
spatial compositional gradient. We found that surface energy density on the substrate surface is the key parameter to control
the composition distribution. Furthermore, the ratio of Fe/Si of the film did not match that of the target. This result shows
that the Si component is selectively etched during the film-forming process. Relatively high laser fluence as well as a very
narrow space between the target and the substrate are essential to etch the film once it is deposited, in order to re-ionize
and etch Si selectively while gravity accelerates both Fe and Si particles to the direction of gravity. We hypothesize that
this process accounts for both the change in the stoichiometry and the formation of composition distribution. 相似文献
8.
Takashi Kajiwara Takashi Nishiyama Sachi Morinaga Kunihito Nagayama 《Applied Physics A: Materials Science & Processing》2010,101(4):739-742
We carried out the thin film deposition of iron silicide by pulsed laser ablation (PLA) on a sapphire substrate, which was
placed on a high-speed rotating titanium disk. The deposited thin film exhibited a continuous composition gradient. We investigated
how the continuous composition gradient was attained, because the strength of the gravity field in our experiment was far
below that in the experiment on bulk crystalline compounds. In the present study, we obtain the spatial distribution of several
species in the PLA plume of FeSi2 by using an intensified charge-coupled device (ICCD) camera. 相似文献
9.
Archiv der Mathematik - We discuss composition operators on certain subspaces of the Hardy space. The family of subspaces that we deal with are called $$H^2_{\alpha , \beta }$$ which have garnered... 相似文献
10.
We have obtained single-crystal aluminum nitride (AlN) layers on diamond (1 1 1) substrates by metalorganic vapor-phase epitaxy (MOVPE). When the thermal cleaning temperature of the substrate and growth temperature of the AlN layer were below 1100 °C, the AlN layer had multi-domain structures mainly consisting of rotated domains. An interface layer, consisting of amorphous carbon and poly-crystal AlN, was formed between the AlN layer and the diamond substrate. On the other hand, when the thermal cleaning temperature and growth temperature were above 1200 °C, a single-crystal AlN layer was grown and no interface layer was formed. Therefore, we attribute the multi-domain structures to the interface layer. Even at the growth temperature of 1100 °C, by performing the thermal cleaning at 1200 °C, the single-crystal AlN layer was obtained, indicating that the thermal cleaning temperature of the substrate is a critical factor for the formation of the interface layer. The epitaxial relationship between the single-crystal AlN layer and the diamond (1 1 1) substrate was determined to be [0 0 0 1]AlN∥[1 1 1]diamond and [1 0 1¯ 0]AlN∥[1 1¯ 0]diamond. The AlN surface had Al polarity and no inversion domains were observed in the AlN layer. 相似文献