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951.
Lee WJ Lee DH Han TH Lee SH Moon HS Lee JA Kim SO 《Chemical communications (Cambridge, England)》2011,47(1):535-537
Biomimetic mineralization of vertical N-doped carbon nanotubes is demonstrated as a straightforward route for carbon-based mineral nanocomposites. The N-doped sites along the carbon nanotube backbone play the role of nucleation sites for mineralization. 相似文献
952.
The function and the role phytoceramide (PCER) and phytosphingosine (PSO) in the central nervous system has not been well studied. This study was aimed at investigating the possible roles of PCER and PSO in glutamate-induced neurotoxicity in cultured neuronal cells and memory function in mice. Phytoceramide showed neuro-protective activity in the glutamate-induced toxicity in cultured cortical neuronal cells. Neither phytosphingosine nor tetraacetylphytosphingosine (TAPS) showed neuroproective effects in neuronal cells. PCER (50 mg/kg, p.o.) recovered the scopolamine-induced reduction in step-through latency in the passive avoidance test; however, PSO did not modulate memory function on this task. The ameliorating effects of PCER on spatial memory were confirmed by the Morris water maze test. In conclusion, through behavioral and neurochemical experimental results, it was demonstrated that central administration of PCER produces amelioration of memory impairment. These results suggest that PCER plays an important role in neuroprotection and memory enhancement and PCER could be a potential new therapeutic agent for the treatment of neurodegenerative diseases such as Alzheimer's disease. 相似文献
953.
Naphthoimidazolium groups can form unique ionic hydrogen bonds with anions as imidazolium moieties, and in addition, they are fluorescent, so no further elaborative synthesis is needed to introduce a fluorescent group. In this paper, three naphthoimidazolium derivatives were synthesized and studied for the recognition of nucleotides. Compound 1 composed of a single naphthoimidazolium group and quaternary ammonium group did not show any significant fluorescent changes with various anions and nucleotides, such as ATP, GTP, CTP, TTP, UTP, ADP and AMP. A tripodal compound 3 bearing three naphthoimidazolium groups and three quaternary ammonium groups, respectively, showed large fluorescence enhancements with UTP, CTP and TTP and moderate fluorescence enhancements with ATP and pyrophosphate and a fluorescence quenching effect with GTP. On the other hand, compound 2 bearing two naphthoimidazolium groups and two quaternary ammonium groups displayed a selective fluorescence enhancement with ATP and a selective fluorescence quenching effect with GTP in 100% aqueous solution. 相似文献
954.
In this study, an analytical method for the simultaneous separation and characterization of various molecular species of lysophospholipids (LPLs) and phospholipids (PLs) is introduced by employing nanoflow liquid chromatography-electrospray ionization tandem mass spectrometry (nLC-ESI-MS/MS). Since LPLs and PLs in human plasma are potential biomarkers for cancer, development of a sophisticated analytical method for the simultaneous profiling of these molecules is important. Standard species of LPLs and PLs were examined to establish a separation condition using a capillary LC column followed by MS scans and data-dependent collision-induced dissociation (CID) analysis for structural identification. With nLC-ESI-MS/MS, regioisomers of each category of LPLs were completely separated and identified with characteristic CID spectra. It was applied to the comprehensive profiling of LPLs and PLs from a human blood plasma sample and yielded identifications of 50 LPLs (each regioisomer pair of 6 lysophosphatidylcholines (LPCs), 7 lysophosphatidylethanolamines (LPEs), 9 lysophosphatidic acid (LPAs), 2 lysophosphatidylglycerols (LPGs), and 1 lysophosphatidylserine (LPS)) and 62 PLs (19 phosphatidylcholines (PCs), 11 phosphatidylethanolamines (PEs), 3 phosphatidylserines (PSs), 16 phosphatidylinositols (PIs), 8 phosphatidylglycerols (PGs), and 5 phosphatidic acids (PAs)). 相似文献
955.
d-Allose, a rare, naturally occurring monosaccharide, is known to exert anti-proliferative effects on cancer cells. The effects
of d-allose on the cellular membranes of hormone-refractory prostate cancer cell line (DU145), hormone-sensitive prostate cancer
cell line (LNCaP), and normal prostate epithelial cells (PrEC) were studied at the molecular level by phospholipid (PL) profiling
using a shotgun lipidomic method. The molecular structures of 85 PL species including 23 phosphatidylcholines, 12 phosphatidylethanolamines
(PEs), 11 phosphatidylserines (PSs), 16 phosphatidylinositols, 9 phosphatidic acids (PAs), and 14 phosphatidylglycerols (PGs)
were identified by data-dependent collision-induced dissociation of nanoflow liquid chromatography–tandem mass spectrometry,
and the PL amounts were quantified. The addition of d-allose to prostate cancer cell lines during their growth phases had negligible or decreased effects on the relative regulation
of PL species, but several new PS molecules (two for DU145 and three for LNCaP) emerged. In contrast, experiments on the PrEC
cell line revealed that some high abundant species (14:0/14:0-PE, 16:2/16:0-PG, and 20:6/18:1-PA) showed significant increases
in concentration. These findings support a mechanism for the anti-proliferative effect of d-allose on prostate cancer cell lines that involves the induction of programmed cell death since PS molecules are known to
induce apoptosis. Principal component analysis was carried out to examine differences in PL distributions among the three
cell lines promoted by d-allose. 相似文献
956.
Phospholipids make up one of the more important classes of biological molecules. Because of their amphipathic nature and their charge state (e.g., negatively charged or zwitterionic) detection of trace levels of these compounds can be problematic. Electrospray ionization mass spectrometry (ESI-MS) is used in this study to detect very small amounts of these analytes by using the positive ion mode and pairing them with fifteen different cationic ion pairing reagents. The phospholipids used in this analysis were phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylglycerol (PG), phosphatidylserine (PS), phosphatidylinositol (PI), phosphatidic acid (PA), 1,2-diheptanoyl-sn-glycero-3-phosphocholine (DHPC), cardiolipin (CA) and sphingosyl phosphoethanolamine (SPE). The analysis of these molecules was carried out in the single ion monitoring (SIM) positive mode. In addition to their detection, a high performance liquid chromatography and mass spectrometry (HPLC-MS) method was developed in which the phospholipids were separated and detected simultaneously within a very short period of time. Separation of phospholipids was developed in the reverse phase mode and in the hydrophilic interaction liquid chromatography (HILIC) mode HPLC. Their differences and impact on the sensitivity of the analytes are compared and discussed further in the paper. With this technique, limits of detection (LODs) were very easily recorded at low ppt (ng L(-1)) levels with many of the cationic ion pairing reagents used in this study. 相似文献
957.
Solvothermal reactions of manganese(II) chloride tetrahydrate with a bis-tetrazole ligand, 2,6-di(1H-tetrazol-5-yl)naphthalene (H(2)NDT), in N,N'-dimethylformamide (DMF)/MeOH mixed solvent at two slightly different temperatures, 75 and 100 °C, led to two different metal-organic frameworks (MOFs), [Mn(II)(3)O(HNDT)(2)(NDT)(DMF)(3)] (1) and [Mn(II)(5)O(2)(HNDT)(2)(NDT)(2)(DMF)(8)] (2), with different net topologies. Single-crystal X-ray diffraction studies reveal that 1 is constructed from an unprecedented trinuclear building block, [Mn(II)(3)O(CN(4))(6)], as a 6-connected trigonal prismatic secondary building unit (SBU) of topological D(3h) site symmetry, and that the ligand in the HNDT(-1)/NDT(2-) deprotonation states is a linker, where two tetrazole (CN(4)) groups of the ligand are connected via a rigid naphthyl group. The tetrazole groups in 1 adopt a 1,2-μ-bridging mode with the manganese(II) ions to form a μ(3)-oxo trinuclear SBU. The trigonalprismatic SBU in 1 is connected to six neighboring SBUs to form a three-dimensional MOF of acs net topology. 2 is constructed from an unprecedented pentanuclear building block, [Mn(II)(5)O(2)(CN(4))(8)], as an 8-connected tetragonal prismatic SBU of topological D(4h) site symmetry. The tetrazole groups in 2 adopt monodentate, 1,2-μ- and 2,3-μ-bridging bidentate and 1,2,3-μ-bridging tridentate binding modes with the manganese(II) centers to form a bis-μ(3)-oxo pentanuclear SBU of local C(2) site symmetry. The tetragonal prismatic SBU in 2 is connected to eight neighboring SBUs to form a 3-D MOF of bcu net topology. 相似文献
958.
Yourim Yoon Yong-Hyuk Kim Byung-Ro Moon 《Journal of Mathematical Modelling and Algorithms》2011,10(3):269-276
We analyze two essential problems arising from edge-based graph partitioning. We show that one of them is an NP-hard problem
but the other is in P, presenting a novel methodology that links linear algebra theory to the graph problems as a part of
proving the facts. This is a significant trial in that linear algebra, which has been mostly adopted as a theoretical analysis
tool, is practically applied to solving actual graph problems. As a result of the linear algebraic manipulation, we could
devise a linear-time algorithm for the problem in P. 相似文献
959.
In this paper, we investigate a self-normalized invariance principle for a ?-mixing stationary sequence {X j , j ≥ 1} of random variables such that L(x):= E(X 1 2 I{|X 1| ≤ x}) is a slowly varying function at ∞. 相似文献
960.
Jin Young Park Hong Chae Jung G. Seeta Rama Raju Jung Hyun Jeong Byung Kee Moon Jung Hwan Kim Young Kuk Lee 《Current Applied Physics》2013,13(3):441-447
The color rendering index (CRI) and structural stability of cerium doped yttrium aluminum garnet (YAG:Ce) based phosphors have been enhanced by replacing Y3+ ions by larger radius ions (Tb3+, Gd3+, Eu3+, and Sm3+) at the dodecahedral site and replacing Al3+ ions by larger ones (Ga3+, Y3+, Tb3+, Gd3+, and Sm3+) at the octahedral site. These aluminum garnet crystalline powders were prepared by solvothermal reaction method at 300 °C for 48 h. The lattice constant values of synthetic aluminum garnet crystalline powders are larger than that of YAG and the emission wavelength of Ce3+ ion of these samples is longer than that of YAG:Ce. FESEM and TEM studies revealed that the Ln3Ga2Al3O12 and Ln3Al2Al3O12 crystalline powders have 3-dimensional star-like morphology with submicron size and good crystallinity, while, Ln3(LnAl)Al3O12 garnet crystalline powders were cubic crystalline phases and shaped as cubes with the round edge having an approximate diameter of about 200–400 nm. All the prepared powders were grown along (100) direction and crystallized into single crystal. Also, the effects of treatment time and reaction temperature on the structure of aluminum garnet crystalline powders have been investigated. 相似文献