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61.
12 bile acids, including 1 beta-hydroxylated and unsaturated bile acids, have been quantified by capillary gas chromatography/negative ion chemical ionization mass spectrometry, using the trimethylsilyl(TMS) ether derivatives of bile acid pentafluorobenzyl(PFB) esters. The analysis time is 12 min and the minimum measurable amount is 100 fg for each bile acid. Bile acids in 200 microL of serum and 50 microL of urine from healthy human adults were measured. These small sample sizes enhance the practicality of using this method as a screening test for bile acids in the serum and urine of human infants, where small sample size is a major problem. 相似文献
62.
63.
Yohei Uchiyama Shohei Iwasaki Chiaki Ueoka Takashi Fukui Kenzo Okamoto Masayuki Yamaguchi 《Journal of Polymer Science.Polymer Physics》2009,47(4):424-433
Effect of mixing and processing conditions at T‐die extrusion on the structure and mechanical properties is studied for isotactic polypropylene (PP) containing a small amount of β‐form nucleating agent, N,N′‐dicyclohexyl‐2,6‐naphthalenedicarboxamide. It is found that trigonal β crystals are predominantly formed in the extruded samples containing the nucleating agent irrespective of the mixing and processing conditions, leading to the marked mechanical toughness. On the contrary, the molecular orientation is significantly affected by the mixing and processing conditions. In particular, it should be noted that PP molecules in the extruded sheet which was mixed at high temperature (260 °C) and extruded at low temperature (200 °C) orient perpendicular to the applied flow direction. As a result, the sheet shows anomalous mechanical anisotropy. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 424–433, 2009 相似文献
64.
Our recent studies of ferroelectric chiral smectic and super-twisted nematic (ST) multiplexed-matrix liquid-crystal displays (LCDs) and a thin-film-transistor (TFT) active-matrix twisted nematic (TN) LCD are presented, mainly in terms of liquid-crystal material and cell optimization. This is based on a consideration of their electro-optical characteristics. In addition the matrix LCD devices developed through these studies are introduced, including a 12-inch-diagonal video-rate multicolour ferroelectric LCD, a highly multiplexed genuine achromatic ST LCD with a single cell and a 4-inch-diagonal full-colour a-Si TFT-addressed TN LCD for a video display. 相似文献
65.
Yohei Kiyotsuka 《Tetrahedron》2010,66(3):676-6255
Substitution of optically active allylic picolinate, cis R1-CH(OC(O)(2-Py))CHCHR2 (R1=(CH2)2Ph, R2=CH2OTBS), with phenylcopper reagents derived from salt free PhLi (2 equiv) and CuBr·Me2S (2 and 1 equiv, respectively) was highly promoted by MgBr2 (3 equiv), producing anti SN2′ product regio- and stereoselectively. This reagent system was proven to be general with several picolinates (R1, R2: Ph(CH2)2, PMBO(CH2)3, Me, TBSOCH2, PMBOCH2, c-Hex). Furthermore, aryl copper reagents prepared from ArLi, which was in turn prepared by Li-halogen exchange, was proven to be compatible with the substitution in the presence of larger quantity of MgBr2 than that of LiX coproduced by the exchange. Substitution was not interfered with the steric hindrance on aryl coppers (Ar: 2-MeOC6H4, 2,6-(MOMO)2-4-MeC6H2, 2,6-Me2C6H3, etc.). Similarly, stereodefined cis and trans alkenyl, furyl, and thienyl reagents gave the corresponding anti SN2′ products efficiently. 相似文献
66.
Asanuma H Toda T Murayama K Liang X Kashida H 《Journal of the American Chemical Society》2010,132(42):14702-14703
A new foldamer, acyclic threoninol nucleic acid (aTNA), has been synthesized by tethering each of the genetic nucleobases A, G, C, and T to d-threoninol molecules, which were then incorporated as building blocks into a scaffold bearing phosphodiester linkages. We found that with its fully complementary strand in an antiparallel fashion, the aTNA oligomer forms an exceptionally stable duplex that is far more stable than corresponding DNA or RNA duplexes, even though single-stranded aTNA is rather flexible and thus does not take a preorganized structure. 相似文献
67.
We propose and demonstrate a scheme for boosting the efficiency of entanglement distribution based on a decoherence-free subspace over lossy quantum channels. By using backward propagation of a coherent light, our scheme achieves an entanglement-sharing rate that is proportional to the transmittance T of the quantum channel in spite of encoding qubits in multipartite systems for the decoherence-free subspace. We experimentally show that highly entangled states, which can violate the Clauser-Horne-Shimony-Holt inequality, are distributed at a rate proportional to T. 相似文献
68.
We describe a Yb-fiber-based laser comb, with a focus on the relationship between the net-cavity dispersion and frequency noise on the comb. While tuning the net-cavity dispersion from anomalous to normal, we measure the relative intensity noise, offset frequency (f(CEO)) linewidth, and the resulting frequency noise spectrum on the f(CEO). We find that the laser operating at zero net-cavity dispersion has many advantages, including an approximately 100× reduction in free-running f(CEO) linewidth and frequency noise power spectral density when compared to the normal-dispersion regime. At the zero-dispersion point, we demonstrate a phase-locked f(CEO) beat with low residual noise. 相似文献
69.
In this article, we consider the mapping properties of convolution operators with smooth functions on weighted Hardy spaces Hp(w) with w belonging to Muckenhoupt class A∞. As a corollary, one obtains decay estimates of heat semigroup on weighted Hardy spaces. After a weighted version of the div–curl lemma is established, these estimates on weighted Hardy spaces are applied to the investigation of the decay property of global mild solutions to Navier–Stokes equations with the initial data belonging to weighted Hardy spaces. 相似文献
70.
A semi-Lévy process is an additive process with periodically stationary increments. In particular, it is a generalization of a Lévy process. The dichotomy of recurrence and transience of Lévy processes is well known, but this is not necessarily true for general additive processes. In this paper, we prove the recurrence and transience dichotomy of semi-Lévy processes. For the proof, we introduce a concept of semi-random walk and discuss its recurrence and transience properties. An example of semi-Lévy process constructed from two independent Lévy processes is investigated. Finally, we prove the laws of large numbers for semi-Lévy processes. 相似文献