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81.
Nagarajan S Taskent-Sezgin H Parul D Carrico I Raleigh DP Dyer RB 《Journal of the American Chemical Society》2011,133(50):20335-20340
The time scale for ordering of the polypeptide backbone relative to the side chains is a critical issue in protein folding. The interplay between ordering of the backbone and ordering of the side chains is particularly important for the formation of β-sheet structures, as the polypeptide chain searches for the native stabilizing cross-strand interactions. We have studied these issues in the N-terminal domain of protein L9 (NTL9), a model protein with mixed α/β structure. We have developed a general approach for introducing site-specific IR probes for the side chains (azide) and backbone ((13)C═(18)O) using recombinant protein expression. Temperature-jump time-resolved IR spectroscopy combined with site-specific labeling enables independent measurement of the respective backbone and side-chain dynamics with single residue resolution. We have found that side-chain ordering in a key region of the β-sheet structure occurs on a slower time scale than ordering of the backbone during the folding of NTL9, likely as a result of the transient formation of non-native side-chain interactions. 相似文献
82.
Hrudananda Jena R. Venkata Krishnan R. Asuvathraman K. Nagarajan K. V. Govindan Kutty 《Journal of Thermal Analysis and Calorimetry》2011,106(3):875-879
Ba10−x
Cs
x
(PO4)6Cl2, (x = 0, 0.5) chloroapatite ceramics were prepared by sonochemical method of synthesis. The measured room temperature lattice
parameters of Ba10 (PO4)6Cl2 and Ba9.5Cs0.5 (PO4)6Cl2−δ are practically the same; that is, a = 10.26 (8), c = 7.65 (7) and a = 10.27 (7), c = 7.65 (5), respectively. Heat capacity measurements were carried out on these materials by differential scanning calorimetry
(DSC) in the temperature range 298–800 K. The heat capacity values of Ba9.5Cs0.5(PO4)6Cl2−δ are found to be slightly higher at all temperatures than those of Ba10(PO4)6Cl2. From the heat capacity data, other thermodynamic functions such as enthalpy and entropy increments were computed. The heat
capacity values of Ba10(PO4)6Cl2 and Ba9.5Cs0.5(PO4)6Cl2−δ at 298 K are 0.3912 and 0.4310 J K−1 g−1, respectively. Thermal expansion property of the doped and undoped barium chloroapatites was measured by using a home built
dilatometer which uses LVDT as displacement sensor. The bulk thermal expansion of Ba10(PO4)Cl2 and Ba9.5Cs0.5(PO4)Cl2−δ is observed to be about 0.9% in the temperature range of 298–973 K. 相似文献
83.
ABSTRACT The mixed metal fluorides containing alkali metals have a range of important applications in optical and electronic devices. Raman spectrums of two such fluorides were examined. Raman spectrum of KCuF3 at 300 K exhibited bands at 261, 295, 363, 468, 519, and 549 cm?1, indicating site symmetry (orthorhombic) lower than the tetragonal symmetry as observed from the powder X-ray diffraction pattern. Cubic KNiF3 showed bands at 410, 468, and 657 cm?1. The first two bands were attributed to the second-order phonon scattering, and the band at 657 cm?1 was assigned to two-magnon peak. 相似文献
84.
Controlled hydrolysis experiments of the heterobimetallic alkoxide {Cu[Al(OPri)4]2}, were investigated. The progress of hydrolysis was monitored by the FT-IR and NMR spectroscopy. A blue colored gel appeared after four days of hydrolysis and the hydrolysis experiments were continued up to ten days. The elemental analysis and FT-IR spectrum revealed the presence of isopropoxy group in the gel obtained even after ten days of hydrolysis. The presence of carbon was further confirmed from the presence of a weak signal at 3.351 ppm in the 13C CP-NMR spectrum. The thermal analysis of the hydrolyzed gels in air also suggested that they were not simple hydroxides of copper and aluminum. The gels on one time heat treatment at 900 °C in air yielded inverse spinel CuAl2O4 as shown by the PXRD patterns. CuO was observed along with CuAl2O4 in the case of the fired product of the gel obtained after five or six days of hydrolysis which was absent in the fired product of ten days hydrolyzed gel. The phase pure spinel was nanocrystalline in nature as revealed by the analysis of PXRD pattern. TEM images revealed porous structured nanocrystallites. The optical property of the spinel was evaluated by the diffuse reflectance spectroscopy. Raman spectrum showed five bands at 767, 698, 595, 450 and 356 cm?1 conforming to the spinel structure. 相似文献
85.
86.
87.
We show, using semiclassical methods, that as a symmetry is broken, the transition between universality classes for the spectral
correlations of quantum chaotic systems is governed by the same parametrization as in the theory of random matrices. The theory
is quantitatively verified for the kicked rotor quantum map. We also provide an explicit substantiation of the random matrix
hypothesis, namely that in the symmetry-adapted basis the symmetry-violating operator is random. 相似文献
88.
In order to elucidate the anomalous magnetic properties in the ferromagnetically ordered state of SmNi4Ga GdNi4Ga and TbNi4Ga, we have carried out a detailed study with magnetization and specific heat (SH) measurements. GdNi4Ga shows the possibility of a filled 3d band and a helical spin arrangement below the ordering temperature. TbNi4Ga shows a dominant crystal field effect resulting in a deviation of TC from the de-Gennes scaling and possible Schottky anomalies in the SH. SmNi4Ga shows a large coercivity at low temperatures. A rough estimate of the domain wall thickness in SmNi4Ga gives a value of 8 Å. 相似文献
89.
In this paper, a new fuzzy linear programming (FLP)-based methodology using a specific membership function named modified logistic membership function is proposed. The modified logistic membership function is first formulated and its flexibility established by an analytical approach. This membership function is tested for its useful performance through an illustrative example by employing FLP. The developed methodology of FLP has provided confidence in applying to real-life industrial production planning problem. This approach of solving industrial production planning problem can provide feedback to the decision maker, implementer and analyst. In such cases, this approach can be called interactive FLP. There is a possibility to design the self-organizing of the fuzzy system for the product mix selection problem in order to find a satisfactory solution. The decision maker, analyst and implementer can incorporate their knowledge and experience to obtain the best outcome. 相似文献
90.
Likely presence of superconductivity in layered nickelates of K2NiF4 structure is pointed out. 相似文献