Showing papers by "Sichuan University published in 2000"
TL;DR: It seems that an ideal bone substitute can be developed by using this type of calcium phosphate cement, which is biocompatible, resorbable in a manner of creeping substitution, osteoconductive and osteoinductive.
300 citations
TL;DR: It is shown that immunotherapy of tumors using fixed xenogeneic whole endothelial cells as a vaccine was effective in affording protection from tumor growth, inducing regression of established tumors and prolonging survival of tumor-bearing mice.
Abstract: The breaking of immune tolerance against autologous angiogenic endothelial cells should be a useful approach for cancer therapy. Here we show that immunotherapy of tumors using fixed xenogeneic whole endothelial cells as a vaccine was effective in affording protection from tumor growth, inducing regression of established tumors and prolonging survival of tumor-bearing mice. Furthermore, autoreactive immunity targeting to microvessels in solid tumors was induced and was probably responsible for the anti-tumor activity. These observations may provide a new vaccine strategy for cancer therapy through the induction of an autoimmune response against the tumor endothelium in a cross-reaction.
240 citations
TL;DR: The present data demonstrate that, like mutations in connexin26, mutations in Cx31 can lead to both recessive and dominant forms of non-syndromic deafness.
Abstract: Mutations in the GJB3 gene encoding connexin31 (Cx31) can cause a dominant non-syndromic form of hearing loss (DFNA2). To determine whether mutations at this locus can also cause recessive non-syndromic deafness, we screened 25 Chinese families with recessive deafness and identified in two families affected individuals who were compound heterozygotes for Cx31 mutations. The three affected individuals in the two families were born to non-consanguineous parents and had an early onset bilateral sensorineural hearing loss. In both families, differing SSCP patterns were observed in affected and unaffected individuals. Sequence analysis in both families demonstrated an in-frame 3 bp deletion (423-425delATT) in one allele, which leads to the loss of an isoleucine residue at codon 141, and a 423A-->G transversion in the other allele, which creates an Ile-->Val substitution at codon 141 (I141V). Neither of these two mutations was detected in DNA from 100 unrelated control subjects. The altered isoleucine residue lies within the third conserved alpha-helical transmembrane domain (M3), which is critical for the formation of the wall of the gap junction pore. Both the deletion of the isoleucine residue 141 and its substitution to valine in the two families could alter the structure of M3, and impair the function of the gap junction. The present data demonstrate that, like mutations in connexin26, mutations in Cx31 can lead to both recessive and dominant forms of non-syndromic deafness.
180 citations
TL;DR: In this paper, the authors presented the results of a study conducted at the Sichuan Institute of Nuclear Science and Technology (INSIT) of the People's Republic of China Physique des Solides Irradie (PRSI) in Chengdu, China.
Abstract: Key Laboratory of Radiation Physics and Technology, Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, People’s Republic of China Physique des Solides Irradie ́s CP234, Universite ́ Libre de Bruxelles, Bd du Triomphe, B-1050 Brussels, Belgium Département de Physique des Mate ́riaux, UniversitéClaude Bernard, Lyon I, 43 Bd du 11 Novembre 1918, Villeurbanne Ce ́dex, France ~Received 19 October 1999 !
130 citations
TL;DR: In this paper, the dispersibility of silicate layers of the montmorillonite in the composites was investigated by using X-ray diffractometer and transmission electron microscopy (TEM).
Abstract: Polypropylene (PP)/montmorillonite (MMT) nanocomposites have been prepared by melt intercalation using organomontmorillonite and conventional twin screw extrusion. The dispersibility of silicate layers of the montmorillonite in the composites was investigated by using X-ray diffractometer and transmission electron microscopy (TEM). The silicate layers of montmorillonite are dispersed at the nanometer level in the PP matrix, as revealed by X-ray and TEM results. The tensile strength of PP/MMT is not much improved compared with pure PP or conventional filled composites. However, the impact strength is greatly improved at lower content of MMT.
© 2000 Society of Chemical Industry
123 citations
TL;DR: In this paper, a Lie algebra arising in each triangulated category with T = 2 = 1, where T is the translation functor, was derived by using the Ringel-Hall algebra approach.
Abstract: By using the Ringel-Hall algebra approach, we find a Lie algebra arising in each triangulated category with T
2=1, where T is the translation functor. In particular, the generic form of the Lie algebras determined by the root categories, the 2-period orbit categories of the derived categories of finite dimensional hereditary associative algebras, gives a realization of all symmetrizable Kac-Moody Lie algebras.
115 citations
TL;DR: In this article, various methods to characterize the pore size and pore distribution of hollow-fiber porous filtration membranes were reviewed, including microscopy observation, thermoporometry, and water permeability.
114 citations
TL;DR: In this paper, a class of set-valued variational inclusions without compactness condition in Banach spaces is introduced and studied, and an existence theorem and an iterative algorithm for solving this kind of variational variational inclusion in the Banach space are established and suggested.
102 citations
TL;DR: In this paper, the structural modifications with central insertions named winged core, solid core and inner diffuser could increase all reduced separation efficiency, separation sharpness, cut size, capacity and flow split, and decrease the energy loss coefficient.
101 citations
TL;DR: The implicit resolvent operator technique is used to study the sensitivity analysis for strongly nonlinear quasi-variational inclusions and the results improve and generalize some of the recent ones.
99 citations
TL;DR: In this article, the null controllability property of the heat equation may be obtained as limit of the exact controllable properties of singularly perturbed damped wave equations.
TL;DR: In this paper, the effects of zinc borate (ZB), aluminum trihydrate (ATH), and their mixture on the flame-retardant and smoke-suppressant properties of poly(vinyl chloride) (PVC) as well as their mechanism for flame retardancy and smoke suppression were studied through the limiting oxygen index (LOI) test, smoke density test, TGA, GC-MS, and SEM.
Abstract: The effects of zinc borate (ZB), aluminum trihydrate (ATH), and their mixture on the flame-retardant and smoke-suppressant properties of poly(vinyl chloride) (PVC) as well as their mechanism for flame retardancy and smoke suppression were studied through the limiting oxygen index (LOI) test, smoke density test, TGA, GC–MS, and SEM. The results show that incorporation of a small amount of ZB, ATH, and their mixture can greatly increase the LOI of PVC and reduce the smoke density of PVC during combustion. The mixture of ZB with ATH has a good synergistic effect on the flame retardance and smoke suppression of PVC. TGA and GC–MS analyses results show that incorporation of a small amount of ZB, ATH, and their mixture greatly promotes the char formation of PVC and decreases the amount of hazardous gases such as benzene and toluene released in PVC during combustion. Their mechanism is also proposed. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3119–3127, 2000
TL;DR: In this paper, the authors showed that Fe(OH)2 precipitates were partially oxidized by H2O2 to ultrafine Fe3O4 powders about 8-10nm in the presence of surfactants.
TL;DR: The aim of this study was to examine pilocytic astrocytomas for genetic alterations that are commonly seen in diffuse astroicytomas.
Abstract: Aims: While it is well known that pilocytic astrocytomas are clinically distinct from diffuse astrocytomas, few comprehensive studies have focused on their genetic differences The aim of this study was to examine pilocytic astrocytomas for genetic alterations that are commonly seen in diffuse astrocytomas
Methods and results:
By using molecular genetic and immunohistochemical techniques, we evaluated p16, p53, CDK4 and PTEN genes in 29 pilocytic astrocytomas Mutation screening of p53 and PTEN was performed by single strand conformation polymorphism analysis followed by direct sequencing Loss of heterozygosity (LOH) of p53, p16 and 10q23–25 loci was performed with microsatellite markers and genomic microsatellite instability (MSI) was also screened Protein expression of p16, p53, CDK4 and PTEN was examined by immunohistochemistry Five tumours were found to have single genetic alterations, which included a p53 mutation, a PTEN mutation, MSI at a single microsatellite marker of the p16 locus, and one single LOH at each p16 and 10q23 loci Protein expressions of p16, CDK4 and PTEN were detected in 73%, 61% and 38% of tumours, respectively Significantly and in sharp contrast to diffuse astrocytomas, no pilocytic astrocytoma in our series stained for p53 protein
Conclusion:
Pilocytic astrocytomas have neither MSI phenotype nor recurrent alterations of the p53 and p16 genes However, altered expression of PTEN may be important in the genesis of pilocytic astrocytomas We conclude that pilocytic astrocytomas are genetically distinct from diffuse astrocytomas Lack of p53 mutation/immunostaining may serve as a diagnostic adjunct for differentiating pilocytic astrocytomas from diffuse astrocytomas in small neurosurgical biopsies
TL;DR: The microstructure and inhomogeneous features of plasma-sprayed hydroxyapatite coatings on titanium substrates have been examined using the time-of-flight secondary ion mass spectroscopy (ToF-SIMS), micro-RamanSpectroscopy and nano-indentation techniques.
TL;DR: In this article, the formation of gold films obtained by low-energy cluster beam deposition at room temperature in ultrahigh vacuum on a gold (111) surface has been analyzed in situ by scanning probe microscopy.
Abstract: The formation of gold films obtained by low-energy cluster beam deposition at room temperature in ultrahigh vacuum on a gold (111) surface has been analyzed in situ by scanning probe microscopy. Neither diffusion of the clusters on the surface, nor coalescence between clusters has been detected. The films are formed by a random pavement of the surface and as a consequence submonolayer films are composed by three-dimensional isolated particles, whereas multilayer films exhibit a nanostructured morphology. Molecular-dynamics simulations, using the same size distribution of incident clusters as in the experiment, reveal the influence of the impact energy on the film morphology. For a low kinetic energy of the incident clusters (0.25 eV/atom), the simulated morphology is in excellent agreement with experimental measurements.
TL;DR: Multi-locational evaluation showed that two new strains named N01 and B07 were superior to the original both in yield and stress resistance and shows itself a promising oil crop, which can be used in industry in China but further studies are needed.
TL;DR: During annealing treatment in air, peroxide ion decomposed and the substituted OH radicals re-enter the HA lattice, resulting in the elimination of the structural aberrations caused by the incorporation of peroxide ions.
Abstract: The incorporation of peroxide ions was confirmed in the heat treatment of hydroxyapatite (HA) powder under air as well as under oxygen atmosphere, by using X-ray diffraction, Raman, and infrared spectroscopy. Peroxide ions associated with vacancies were sited in the channel of HA lattice along the c-axis through the substitution of a portion of OH radicals. The molecular ions constituted a symmetric vibrator with a stretching vibration active in Raman spectrometry. This vibration was recorded at 750 cm(-1) in the Raman spectra of O(2)(2-)-containing HA samples. The final product was a solid solution of hydroxyl- and peroxide-apatite. However, the existence of peroxide ions in the HA lattice caused the contraction of the unit-cell dimensions of HA materials. In addition, a new hydrogen bond was formed between peroxide ions and adjacent OH radicals by using molecular spectroscopy analysis. During annealing treatment in air, peroxide ions decomposed and the substituted OH radicals re-enter the HA lattice, resulting in the elimination of the structural aberrations caused by the incorporation of peroxide ions. Concentration of the peroxide ions included in HA samples was measured by chemical analysis.
10 Jul 2000
TL;DR: Optimal fusion rules in the sense of best linear unbiased estimation (BLUE), weighted least squares (WLS), and their generalized versions are presented for cases with either complete, incomplete, or no prior information.
Abstract: This paper deals with data fusion for the purpose of estimation. Three fusion architectures are considered: centralized, distributed, and hybrid. A unified linear model and general framework for these three architectures are established. Optimal fusion rules in the sense of best linear unbiased estimation (BLUE), weighted least squares (WLS), and their generalized versions are presented for cases with either complete, incomplete, or no prior information. These rules are much more general and flexible than previous results. For example, they are in a unified form that are optimal for all the three fusion architectures with arbitrary correlation of local estimates or observation noises across sensors or across time. They are also in explicit forms convenient for implementation. The relationships among these rules are also presented.
TL;DR: The closed-form propagation expressions for the beamlets and the resulting beam are given, which enable us to study beam propagation properties of radial laser arrays for both phase-locked and non-phase-locked cases.
Abstract: A detailed study of phase-locked and non-phase-locked radial laser arrays is presented. The closed-form propagation expressions for the beamlets and the resulting beam are given, which enable us to study beam propagation properties of radial laser arrays for both phase-locked and non-phase-locked cases. Numerical calculation examples are given to illustrate the application of our analytical results and the differences between phase-locked and non-phase-locked radial arrays.
08 Nov 2000
TL;DR: In this article, the convergence theorems of modified Ishikawa and Mann iterative sequences with errors for asymptotically pseudo-contractive and asymPTotically nonexpansive mappings in Banach space are obtained.
Abstract: Some convergence theorems of modified Ishikawa and Mann iterative sequences with errors for asymptotically pseudo-contractive and asymptotically nonexpansive mappings in Banach space are obtained. The results presented in this paper improve and extend the corresponding results in Goebel and Kirk (1972), Kirk (1965), Liu (1996), Schu (1991) and Chang et al. (to appear).
19 Jun 2000
TL;DR: Five algorithms, including Naive Algorithm for tutor topic tree and Level-generate Algorithm to generate a Web tutor topic of K+1 levels, are proposed, and the experimental results are presented.
Abstract: In order to adapt the teaching in accordance to an individual student's ability in a distance learning environment, a method to construct personalized courseware is proposed by building a personalized Web tutor tree and mining both context and structure of the courseware. The concept of Web tutor objects and the notion of similarity are proposed. Five algorithms, including Naive Algorithm for tutor topic tree and Level-generate Algorithm to generate a Web tutor topic of K+1 levels, and the experimental results are presented.
TL;DR: In this paper, the quark delocalization and color screening model was applied to nucleon-baryon scattering and a semi-quantitative fit to N − N, N − Λ and N - Σ phase shifts and scattering cross sections was obtained without invoking meson exchange.
TL;DR: In this paper, experimental electron-impact K-shell ionization cross sections obtained from a search of the literature up to December 1999 are tabulated according to atomic number and incident electron energy.
TL;DR: In this paper, the results of the unit cell parameters of Mg-Al spinels solid solutions with XRD and a formula for calculating the lattice parameter of such spinel compounds were provided.
Abstract: Mg-Al spinel is the most typical material in the family of chemical compounds with spinel crystalline structure that exhibits many applications [1, 2]. In general, it can be noted as MgO-n·Al2O3. MgAl2O4 spinel is an fcc structure of oxygen ions with a lattice parameter of 0.808 nm. There are eight molecules in its unit cell, in which there are 64 tetrahedral symmetry sites and 32 octahedral ones. In the perfect case, magnesium ions occupy 8 tetrahedral positions and aluminum ions occupy 16 octahedral sites [3]. In many cases, this MgO-n·Al2O3 compound is nonstoichiometric, n is not equal to 1. Form 1 up to 7.3, the excess Al3+ ions occupying tetrahedral sites, substitute for Mg2+ ions [4]. This causes a proportional decrease of lattice parameter with the amount of excess Al3+ due to a smaller diameter of Al3+ than that of Mg2+. In the present paper, we show the result of the unit cell parameters of Mg-Al spinels solid solutions with XRD and provide a formula for calculating the lattice parameter of such Mg-Al spinel compounds, which has a good physical meaning compared with that given by Sigalovsky et al. [5]. In our experiments ultra-fine powders of Mg-Al spinel were prepared with a method of high temperature solid reaction. Reagent grade AlNH4(SO4)2·12H2O and MgSO4·7H2O were mixed based on different n in de-ionized water. These solutions were calcimined at 1080 ◦C for 4–5 h to obtain a single spinel phase powder with being high pure, good disperse and homogeneous. The obtained powders were measured by XRD using Cu-Kα radiation on a D/max rA diffractometer. The XRD patterns of the obtained powder samples are given in Fig. 1. The stoichiometric spinel XRD pattern (a pattern labelled n= 1.0) is the same as the standard powder XRD pattern [6]. For the non-stoichiometric spinel samples, the peaks shift to the direction in higher values of 2θ as n increases. That means the distance of (hkl) plane dhkl became smaller according to the following expression:
TL;DR: A discretized iterative algorithm is suggested that can provide approximate solutions to the necessary conditions for optimum distributed sensor decision rules under a fixed fusion rule, and the algorithm is shown to converge in a finite number of iterations.
Abstract: Optimum-distributed signal detection system design is studied for cases with statistically dependent observations from sensor to sensor. The common parallel architecture is assumed. Here, each sensor sends a decision to a fusion center that determines a final binary decision using a nonrandomized fusion rule. General L sensor cases are considered. A discretized iterative algorithm is suggested that can provide approximate solutions to the necessary conditions for optimum distributed sensor decision rules under a fixed fusion rule. The algorithm is shown to converge in a finite number of iterations, and the solutions obtained are shown to approach the solutions to the original problem, without discretization, as the variable step size shrinks to zero. In the formulation, both binary and multiple-bit sensor decisions cases are considered. Illustrative numerical examples are presented for two-, three-, and four-sensor cases, in which a common random Gaussian signal is to be detected in Gaussian noise.
TL;DR: Based on a generalized truncated second-order irradiance moments definition, an analytical generalized beam propagation factor (M G 2 -factor) of hard-edge diffracted cosh-Gaussian beams is derived and illustrated numerically as discussed by the authors.
TL;DR: In this paper, an isomeric study for N 5, N 5 +, and N 5− has been carried out using the Gaussian-3 (G3) method, and the most stable N5 isomer is a weak N2⋯N3 complex with C2v symmetry.
TL;DR: A mutant chlorophyll-reduced (Cr) seedling with yellow-green cotyledons and leaves was obtained from the Brassica napus inbred line 3529 induced by fast neutron and diethyl sulphate; however, when the Cr gene was in the heterozygous condition, no deleterious effects on yield characteristics and disease resistance were observed.
Abstract: A mutant chlorophyll-reduced (Cr) seedling with yellow-green cotyledons and leaves was obtained from the Brassica napus inbred line 3529 induced by fast neutron and diethyl sulphate (DES). Genetic analysis revealed that the Cr seedling marker trait was controlled by a pair of recessive genes. A randomized complete block design was used to evaluate its agronomic performance. Results from 2 years of tests indicated that the seed yield of Cr lines was significantly lower than that of normal green plants; however, when the Cr gene was in the heterozygous condition, no deleterious effects on yield characteristics and disease resistance were observed. The Cr seedling marker trait was introduced into male-sterile lines, and Cr male-sterile lines revealed the same superior combining ability as normal chlorophyll (Nc) lines. The Cr trait can therefore be used as a marker to produce hybrid seed.
TL;DR: In this article, a new class of quasi-variational inequalities called generalized nonlinear set-valued mixed quasivariational inequalities is introduced and studied, which is called the generalized non-linear setvalued mixed quasi-varianational inequality.
Abstract: In this paper, we introduce and study a new class of quasi-variational inequalities, which is called the generalized nonlinear set-valued mixed quasi-variational inequality. Using the resolvent operator technique for maximal monotone mapping, we construct some new iterative algorithms for solving this class of generalized nonlinear set-valued mixed quasi-variational inequalities. We prove the existence of solution for this kind of generalized nonlinear set-valued mixed quasivariational inequalities without compactness and the convergence of iterative sequences generated by the algorithms. We also discuss the convergence and stability of perturbed iterative algorithm for solving a class of generalized nonlinear mixed quasi-variational inequalities.