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981.
Urine samples were collected during the daytime and nighttime from spontaneously hypertensive model rats and normal rats without dosing. The 1H NMR spectra were measured for their urine samples, and analyzed by a pattern recognition method, known as Principal Component Analysis (PCA) and Soft Independent Modeling of Class Analogy (SIMCA). The separation of urinary data due to the diurnal variation (daytime and nighttime) and also to the difference between the two strains of rat was achieved in the PCA score plot. Differences of the urinary profiles in the respective separation were effectively extracted as marker variables by the SIMCA method. NMR measurements coupled with pattern recognition methods provide a straightforward approach to inspect the disease metabolic status and the preliminary screening tool of marker candidates for further development.  相似文献   
982.
983.
Bulk-optic current sensors have been developed for electric power systems. This current sensor has a glass ring type Faraday cell, where a light beam circulates around a current-carrying-conductor to precisely measure the current. Fundamental performances and practical applications are described.  相似文献   
984.
Poly(L ‐lactide) (PLLA) with terminal primary amino groups (PLLA‐NH2) was synthesized and used to construct PLLA‐grafted pullulan (Pul‐g‐PLLA). It consisted of a hydrophilic carboxymethyl Pul (CM‐Pul) main chain and hydrophobic PLLA graft chains that were created through a direct coupling reaction between PLLA‐NH2 and CM‐Pul using 2‐ethoxy‐1‐(ethoxycarbonyl)‐1,2‐dihydroquinoline as a condensation reagent. Pul‐g‐PLLAs with over 78 wt % sugar unit content were found to form nanometer‐sized aggregates in water. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5482–5487, 2004  相似文献   
985.
A new method has been developed for the determination of residual stresses in a cylinder. Boring out or removing layers from outside induces changes in the length and diameter of the remaining bar. The initial distributions of the stresses are derived from measurements of the length change only. Details of equations required for the calculations are described. The method rests on an assumption that the radial displacement just below a surface is equal to the radial displacement at a new surface after removal of the surface layer of material. This assumption leads to relations between the three residual-stress components. The numerical calculations of these relations agree well with the experimental data for quenched cylinders obtained by using the Sachs method in other investigations. A brief general discussion is given on the equilibrium conditions of the residual stresses determined.  相似文献   
986.
The Rouse model is a well established model for nonentangled polymer chains and its dynamic behavior under step strain has been fully analyzed in the literature. However, to the knowledge of the authors, no analysis has been made for the orientational anisotropy for the Rouse eigenmodes during the creep and creep recovery processes. For completeness of the analysis of the Rouse model, this anisotropy is calculated from the Rouse equation of motion. The calculation is simple and straightforward, but the result is intriguing in a sense that respective Rouse eigenmodes do not exhibit the single Voigt-type retardation. Instead, each Rouse eigenmode has a distribution in the retardation time. This behavior, reflecting the interplay among the Rouse eigenmodes of different orders under the constant stress condition, is quite different from the behavior under rate-controlled flow (where each eigenmode exhibits retardation/relaxation associated with a single characteristic time).List of abbreviations and symbols a Average segment size at equilibrium - Ap(t) Normalized orientational anisotropy for the p-th Rouse eigenmode defined by Eq. (14) - p-th Fourier component of the Brownian force (=x, y) - FB(n,t) Brownian force acting on n-th segment at time t - G(t) Relaxation modulus - J(t) Creep compliance - JR(t) Recoverable creep compliance - kB Boltzmann constant - N Segment number per Rouse chain - Qj(t) Orientational anisotropy of chain sections defined by Eq. (21) - r(n,t) Position of n-th segment of the chain at time t - S(n,t) Shear orientation function (S(n,t)=a–2<ux(n,t)uy(n,t)>) - T Absolute temperature - u(n,t) Tangential vector of n-th segment at time t (u = r/n) - V(r(n,t)) Flow velocity of the frictional medium at the position r(n,t) - Xp(t), Yp(t), and Zp(t) x-, y-, and z-components of the amplitudes of p-th Rouse eigenmode at time t - Strain rate being uniform throughout the system - Segmental friction coefficient - 0 Zero-shear viscosity - p Numerical coefficients determined from Eq. (25) - Gaussian spring constant ( = 3kBT/a2) - Number of Rouse chains per unit volume - (t) Shear stress of the system at time t - steady Shear stress in the steadily flowing state - R Longest viscoelastic relaxation time of the Rouse chain  相似文献   
987.
Although all the pure‐carbon fullerene isomers above C60 reported to date comply with the isolated pentagon rule (IPR), non‐IPR structures, which are expected to have different properties from those of IPR species, are obtainable either by exohedral modification or by endohedral atom doping. This report describes the isolation and characterization of a new endohedral metallofullerene (EMF), La2@C76, which has a non‐IPR fullerene cage. The X‐ray crystallographic result for the La2@C76/[NiII(OEP)] (OEP=octaethylporphyrin) cocrystal unambiguously elucidated the Cs(17 490)‐C76 cage structure, which contains two adjacent pentagon pairs. Surprisingly, multiple metal sites were distinguished from the X‐ray data, which implies dynamic behavior for the two La3+ cations inside the cage. This dynamic behavior was also corroborated by variable‐temperature 139 La NMR spectroscopy. This phenomenon conflicts with the widely accepted idea that the metal cations in non‐IPR EMFs invariably coordinate strongly with the negatively charged fused‐pentagon carbons, thereby providing new insights into modern coordination chemistry. Furthermore, our electrochemical and computational studies reveal that La2@Cs(17 490)‐C76 has a larger HOMO–LUMO gap than other dilanthanum‐EMFs with IPR cage structures, such as La2@D3h(5)‐C78 and La2@Ih(7)‐C80, which implies that IPR is no longer a strict rule for EMFs.  相似文献   
988.
Abstract

Small-sized chitosan-gel nanospheres, CNSs (average diameter 250 nm), containing 5-fluorouracil (5FU) or immobilizing 5FU derivatives (aminopentyl-carbamoyl-5FU or aminopentyl-ester-methylene-5FU) were prepared by the glutaraldehyde crosslinking technique and the emulsion method. When chitosan was crosslinked with glutaraldehyde, these 5FU derivatives were simultaneously immobilized to CNSs by means of Schiff's base formation. The CNSs were coated with anionic polysaccharides, such as 6-O-carboxymethyl-N-acetyl-α-l,4-polygalactosamine/Na (CM-NAPGA/Na), 6-O-carboxymethyl-chitin/Na (CM-chitin/Na), and sodium hyaluronate, through formation of a polyelectrolyte complex membrane to give CNS/polyanion, i.e., CNS/G, CNS/C, and CNS/H, respectively. The polyelectrolyte complex of polysaccharide was employed to achieve the controlled release and effective targeting of 5FU by the CNSs. The release rate of 5FU from the CNSs could be controlled by immobilization of 5FU, degree of deacetylation of chitosan used and coating with polysaccharides. Since very few galactosamine residues are known to be able to cross-react with ligands for galactose, the galactosamine residues on the surface of CNS/Gs are expected to act as the targeting moieties for hepatocyte. The CNS/G showed the lectinmediated aggregation phenomenon by the addition of APA lectin. Moreover, CNS/G had the highest cytotoxic activity among the three kinds of CNS/polyanion and CNS in HLE human hepatoma cell culture system in vitro.  相似文献   
989.
The polymerization of vinyl monomer initiated by an aqueous solution of sodium polystyrenesulfonate (PSS-Na) was carried out at 85°C. Methyl methacrylate (MMA) and styrene were polymerized, while acrylonitrile was not. The rate of polymerization of MMA decreased with the increase of the degree of polymerization of PSS-Na. However, the polymerization was not initiated by sodium ethyl benzenesulfonate which was a unit molecule of PSS-Na. The polymerization proved to be a radical reaction. The polymerization was considered to commence with the formation of hydrophobic areas with PSS-Na in the aqueous phase. MMA is incorporated into these areas, and there the polymerization is initiated and proceeds. The hydrophobic areas were assumed to be similar to the micelles formed by anionic detergents such as sodium alkylbenzene sulfonate. An initiation mechanism is proposed.  相似文献   
990.
Photoirradiations onto polycyclic acetals, i. e., polymers containing cyclic acetal groups in the molecule, were carried out at 30 or 40°C. The terpolymer of vinyl formal/vinyl acetate/vinyl alcohol (PVFAcA) was decomposed by means of irradiation, while poly-2-vinyl-1,3-dioxolane (PVDO) and poly-2-vinyl-4-hydroxy-methyl-1,3-dioxolane (PVHDO) were crosslinked. These results indicate the possibility of control of the decomposition or the crosslinking of polymer.  相似文献   
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