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951.
In suspensions of Nafion beads and of cationic gel beads, NMR spectroscopy showed two water-proton resonances, one representing intimate water layers next to the polymer surface, the other corresponding to water lying beyond. Both resonances show notably shorter spin-lattice relaxation times (T1) and smaller self-diffusion coefficients (D) indicating slower dynamics than bulk water. These findings confirm the existence of highly restricted water layers adsorbed onto hydrophilic surfaces and dynamically stable water beyond the first hydration layers. Thus, aqueous regions on the order of micrometers are dynamically different from bulk water. 相似文献
952.
Sunkyu Choi Jaeyoon Kim Kun Cho Gunwook Park Jong Hyuk Yoon Sehoon Park Jong Shin Yoo Sung Ho Ryu Young Hwan Kim Jeongkwon Kim 《Rapid communications in mass spectrometry : RCM》2010,24(10):1467-1474
Protein phosphorylation regulates a wide range of cellular functions and is associated with signaling pathways in cells. Various strategies for enrichment of phosphoproteins or phosphopeptides have been developed. Here, we developed a novel sequential phosphopeptide enrichment method, using magnetic iron oxide (Fe3O4) and titanium dioxide (TiO2) particles, to detect mono‐ and multi‐phosphorylated peptides. In the first step, phosphopeptides were captured on Fe3O4 particles. In a subsequent step, any residual phosphopeptides were captured on TiO2 particles. The particles were eluted and rinsed to yield phosphopeptide‐enriched fractions that were combined and analyzed using liquid chromatography/tandem mass spectrometry (LC/MS/MS). The validity of this sequential Fe3O4/TiO2 enrichment strategy was demonstrated by the successful enrichment of bovine α‐casein phosphopeptides. We then applied the sequential Fe3O4/TiO2 enrichment method to the analysis of phosphopeptides in L6 muscle cell lysates and successfully identified mono‐ and multi‐phosphorylated peptides. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
953.
954.
Kim Kun-Woo Lee Jae-Wook Jang Jin-Seok Oh Joo-Young Kang Ji-Heon Kim Hyung-Ryul Yoo Wan-Suk 《Nonlinear dynamics》2017,87(2):1139-1151
Nonlinear Dynamics - Absolute nodal coordinate formulation was developed in the mid-1990s. The adoption of the continuum mechanics concept has allowed large displacements and large deformations to... 相似文献
955.
Min Ku Jeon Tae-Sic Yoo Eun-Young Choi Jin-Mok Hur 《Journal of Radioanalytical and Nuclear Chemistry》2017,311(1):155-163
This paper discusses the development of a separation method for isolation of 171Tm from a half-gram irradiated erbium target in support of stockpile stewardship and astrophysics research. The developed procedure is based on cation exchange separation using alpha-hydroxyisobutyric acid (α-HIBA) as chelating agent. It is able to achieve either a decontamination factor of 1.4(4) × 105 with 68.9(3) % recovery or 95.4(3) % recovery with a decontamination factor of 5.82(7) × 103 for a mock 500-mg target containing 17.9 mg thulium in a single pass-through at room temperature. 相似文献
956.
957.
The effects of an electric field on the interband transitions in InxGa1−xAs/InyAl1−yAs coupled step quantum wells have been investigated both experimentally and theoretically. A InxGa1−xAs/InyAl1−yAs coupled step quantum well sample consisted of the two sets of a 50 Å In0.53Ga0.47As shallow quantum well and a 50 Å In0.65Ga0.35As deep step quantum well bounded by two thick In0.52Al0.48As barriers separated by a 30 Å In0.52Al0.48As embedded potential barrier. The Stark shift of the interband transition energy in the InxGa1−xAs/InyAl1−yAs coupled step quantum well is larger than that of the single quantum well, and the oscillator strength in the InxGa1−xAs/InyAl1−yAs coupled step quantum well is larger than that in a coupled rectangular quantum well. These results indicate that InxGa1−xAs/InyAl1−yAs coupled step quantum wells hold promise for potential applications in optoelectron devices, such as tunable lasers. 相似文献
958.
A new algorithm for downdating a QR decomposition is presented. We show that, when the columns in the Q factor from the Modified Gram-Schmidt QR decomposition of a matrixX are exactly orthonormal, the Gram-Schmidt downdating algorithm for the QR decomposition ofX is equivalent to downdating the full Householder QR decomposition of the matrixX augmented by ann ×n zero matrix on top. Using this relation, we derive an algorithm that improves the Gram-Schmidt downdating algorithm when the columns in the Q factor are not orthonormal. Numerical test results show that the new algorithm produces far more accurate results than the Gram-Schmidt downdating algorithm for certain ill-conditioned problems.This work was partially supported in part by the National Science Foundation grants CCR-9209726 and CCR-9509085. 相似文献
959.
Chung‐Yul Yoo Kun‐Pyo Hong Seung‐Joo Kim 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(8):i63-i65
The structure of a new layered oxyfluoride, viz. potassium strontium diniobium hexaoxide fluoride, KSrNb2O6F, was refined from powder neutron diffraction data in the orthorhombic space group Immm. The oxyfluoride compound is an n = 2 member of the Dion–Jacobson‐type family of general formula A[A′n−1BnX3n+1], which consists of double layered perovskite slabs, [SrNb2O6F]−, between which K+ ions are located. Within the perovskite slabs, the NbO5F octahedra are significantly distorted and tilted about the a axis. A bond‐valence‐sum calculation gives evidence for O/F ordering in KSrNb2O6F, with the F− ions located in the central sites of the corner‐sharing NbO5F octahedra along the b axis. All atoms lie on special positions, namely Nb on m, Sr on mmm, K on m2m, F on mm2, and O on sites of symmetry m and m2m. 相似文献
960.
Hak Su Kim Su-Jin Moon Sang Eun Lee Gi Won Hwang Hyun Ju Yoo Jin Woo Song 《Experimental & molecular medicine》2021,53(5):864
Epoxyeicosatrienoic acids (EETs) are metabolites of arachidonic acid that are rapidly metabolized into diols by soluble epoxide hydrolase (sEH). sEH inhibition has been shown to increase the biological activity of EETs, which are known to have anti-inflammatory properties. However, the role of EETs in pulmonary fibrosis remains unexplored. Liquid chromatography with tandem mass spectrometry (LC-MS/MS) was used to analyze EETs in the lung tissues of patients with idiopathic pulmonary fibrosis (IPF, n = 29) and controls (n = 15), and the function of 11,12-EET was evaluated in in vitro and in vivo in pulmonary fibrosis models. EET levels in IPF lung tissues, including those of 8,9-EET, 11,12-EET, and 14,15-EET, were significantly lower than those in control tissues. The 11,12-EET/11,12-DHET ratio in human lung tissues also differentiated IPF from control tissues. 11,12-EET significantly decreased transforming growth factor (TGF)-β1-induced expression of α-smooth muscle actin (SMA) and collagen type-I in MRC-5 cells and primary fibroblasts from IPF patients. sEH-specific siRNA and 1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea (TPPU; sEH inhibitor) also decreased TGF-β1-induced expression of α-SMA and collagen type-I in fibroblasts. Moreover, 11,12-EET and TPPU decreased TGF-β1-induced p-Smad2/3 and extracellular-signal-regulated kinase (ERK) expression in primary fibroblasts from patients with IPF and fibronectin expression in Beas-2B cells. TPPU decreased the levels of hydroxyproline in the lungs of bleomycin-induced mice. 11,12-EET or sEH inhibitors could inhibit pulmonary fibrosis by regulating TGF-β1-induced profibrotic signaling, suggesting that 11,12-EET and the regulation of EETs could serve as potential therapeutic targets for IPF treatment.Subject terms: Respiratory tract diseases, Chronic inflammation 相似文献