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关于归纳推理的辩护问题——一种基于质量互变规律的思考 被引量:1
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作者 李春泰 《哈尔滨学院学报》 2001年第1期29-30,共2页
本文从质量互变规律的角度 ,说明归纳推理之所以可能从有限个前题即特殊过渡到一般 。
关键词 归纳推理 特称陈述 全称陈述 质量互变规律 形式逻辑 质变点
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中国现当代文学批评史的分期问题 被引量:2
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作者 林炜娜 《广东第二师范学院学报》 2017年第4期33-39,共7页
目前学界对中国现当代文学批评史起点研究有着三种具有代表性的观点:"晚清说""五四说"及"20世纪整体观照说",这是研究者根据具体批评著作、文学活动或政治历史事件对文学批评发展进程所作的价值判断,体... 目前学界对中国现当代文学批评史起点研究有着三种具有代表性的观点:"晚清说""五四说"及"20世纪整体观照说",这是研究者根据具体批评著作、文学活动或政治历史事件对文学批评发展进程所作的价值判断,体现了研究者们在批评史编写过程中的分期立场和理论依据。在差异之下,建构科学合理的批评史分期需要把握三个关系:一是处理好文学批评史与文学史的关系;二是处理好批评史中断裂和继承的关系;三是把握历史的整体发展与阶段性停滞甚至后退的关系。在此基础上,可将中国现当代文学批评史以1917年王国维《<红楼梦>评论》为起点,其"现代性"特征延伸至1942年文代会的召开,20世纪40年代—70年代为当代文学批评的过渡期,1978年后进入到以多元化审美模式为特点的当代文学批评期。 展开更多
关键词 文学批评史 分期起始 质变点 现代性
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A Simple and Easy Method for Site-specific Mutagenesis Using Long-distance Inverse PCR in the Presence of Pfu-DNA Polymerase 被引量:9
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作者 董宇清 于昕 赵进东 《Acta Botanica Sinica》 CSCD 2000年第5期539-541,共3页
Site_specific mutagenesis has been widely used in molecular biology and biochemistry. The authors have developed a simple and easy method for site_specific mutagenesis of any genes on plasmids using long distance inve... Site_specific mutagenesis has been widely used in molecular biology and biochemistry. The authors have developed a simple and easy method for site_specific mutagenesis of any genes on plasmids using long distance inverse PCR in the presence of Pfu_DNA polymerase. The efficiency of this method is higher than 90% and the entire procedure can be performed just in one tube. No subcloning is needed. This method is especially useful for obtaining mutant genes on large plasmids such as Ti plasmids used for plant transformation. 展开更多
关键词 long_distance inverse PCR PLASMID site_specific mutagenesis
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Overexpression and mutations of tumor suppressor gene p53 in hepatocellular carcinoma
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作者 王东 史景泉 《World Journal of Gastroenterology》 SCIE CAS CSCD 1996年第3期161-164,共4页
AIMS To examine the prevalance of p53 mutations in hepatocellular carcinoma (HCC) from Chongqing area and the relationship between the p53 mutations and clinicopathological features of HCC,as well as the risk factors.... AIMS To examine the prevalance of p53 mutations in hepatocellular carcinoma (HCC) from Chongqing area and the relationship between the p53 mutations and clinicopathological features of HCC,as well as the risk factors. METHODS The overexpression and point mutations of tumor suppressor gene p53 in 38 cases of HCC were detected by a sensitive antigen retrieval fluid (ARF) immunohistochemical method and polymerase chain re- action(PCR)-restriction fragment length polymorphism (RFLP),and single strand conformation polymorphism (SSCP)-silver staining analysis. RESULTS The results showed that 16 of 38 HCCs had positive p53 protein (42.1%),7 HCCs had p53 mutation at 249 (18.4 % ) and 2 HCCS had point muta- tion within exon 7 other than 249. Among 9 cases of HCC with mutations,8 cases demonstrated positive p53 protein,its coincidental rate was 88.9%. The overexpression and mutations of p53 were significantly related to the differentiation and metastasis of HCCs. The frequency of p53 mutations was consistent with high prevalence of HBV and a moderate aflatoxin B1 (AFB1) exposure in our area. CONCLUSIONS The results suggest that AFB1 acts synergistically with HBV in the generation of p53 mutations. Furthermore,dietary exposure to AFB1 may mainly contribute to the tumor specific mutation at codon 249,while HBV may account for other scattered mutations in HCC. 展开更多
关键词 liver neoplasms GENES SUPPRESSOR tumor protein p53 point mutation
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Melting heat transfer with radiative effects and homogeneous–heterogeneous reaction in thermally stratified stagnation flow embedded in porous medium 被引量:4
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作者 M.JAVED M.FAROOQ +1 位作者 S.AHMAD Aisha ANJUM 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第11期2701-2711,共11页
The present article deals with thermally stratified stagnation-point flow saturated in porous medium on surface of variable thickness along with more convincing and reliable surface condition termed as melting heat tr... The present article deals with thermally stratified stagnation-point flow saturated in porous medium on surface of variable thickness along with more convincing and reliable surface condition termed as melting heat transfer.Homogeneous–heterogeneous reaction and radiative effects have been further taken into account to reconnoiterproperties of heat transfer.Melting heat transfer and phenomenon of homogeneous–heterogeneous reaction have engrossed widespread utilization in purification of metals,welding process,electroslag melting,biochemical systems,catalysis and several industrial developments.Suitable transformations are utilized to attain a scheme of ordinary differential equations possessing exceedingly nonlinear nature.Homotopic process is employed to develop convergent solutions of the resulting problem.Discussion regarding velocity,thermal field and concentration distribution for several involved parameters is pivotal part.Graphical behaviors of skin friction coefficient and Nusselt number are also portrayed.Concentration of the reactants is found to depreciate as a result of strength of both heterogeneous and homogeneous reaction parameters.With existence of melting phenomenon,declining attitude of fluid temperature is observed for higher radiation parameter. 展开更多
关键词 melting heat transfer porous medium stagnation point variable sheet thickness homogeneous– heterogeneous reaction
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Mass genetics study of rhodopsin point mutations in retinitis pigmentosa
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作者 张晓莉 阴正勤 +1 位作者 张雪 府伟灵 《Journal of Medical Colleges of PLA(China)》 CAS 2004年第5期297-301,共5页
Objective: To evaluate the incidence and pattern of rhodopsin (RHO) mutations in Chinese patients with retinitis pigmentosa (RP). Methods: Conformation sensitive gel electrophoresis (CSGE) and direct DNA sequencing we... Objective: To evaluate the incidence and pattern of rhodopsin (RHO) mutations in Chinese patients with retinitis pigmentosa (RP). Methods: Conformation sensitive gel electrophoresis (CSGE) and direct DNA sequencing were applied to detect point mutations that occurred in the five coding exons and splice sites of RHO gene in 98 index patients with RP. Results: Four patients of one ADRP family were found to have a missense mutation at codon 347, Pro347Leu. One late-onset RP patient and her daughter, without clinical expression at present, were discovered to have a novel frameshift mutation at codon 327, Pro327 (1-bp del) . Neither of the two mutations was found in 100 normal controls. Ala299Ser was found in one RP patient. Two control subjects also had Ala299Ser, suggesting its nonpathogenicity and just single nucleotide polymorphism (SNP). Conclusion: Two RP patients had rhodopsin mutations, thus the expected frequency of RHO mutations in RP is about 2.0% (95% confidence interval: 0.3%-4.4%). A highly conserved C-terminal sequence QVS(A) PA was altered due to Pro347Leu and thereby misdirecting rhodopsin to incorrect subcellular location. Loss of all phosphory-lation sites at the C-terminus and a highly conserved sequence QVS(A)PA may occur because of Pro327(1-bp del) . To elucidate the predominant biochemical defects in such mutant, transgenic mice and transfected culture cells carrying Pro327(1-bp del) would be of great value. 展开更多
关键词 retinitis pigmentosa RHODOPSIN MUTATION conformation sensitive gel electrophoresis SEQUENCING
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Genetic Variation Assessed with Microsatellites in Mass Selection Lines of the Pacific Oyster (Crassostrea gigas) in China 被引量:2
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作者 WANG Xubo LI Qi +1 位作者 YU Hong KONG Lingfeng 《Journal of Ocean University of China》 SCIE CAS 2016年第6期1039-1045,共7页
Abstract Four successive mass selection lines of the Pacific oyster, Crassostrea gigas, selected for faster growth in breeding pro- grams in China were examined at ten polymorphic microsatellite loci to assess the lev... Abstract Four successive mass selection lines of the Pacific oyster, Crassostrea gigas, selected for faster growth in breeding pro- grams in China were examined at ten polymorphic microsatellite loci to assess the level of allelic diversity and estimate the effective population size. These data were compared with those of their base population. The results showed that the genetic variation of the four generations were maintained at high levels with an average allelic richness of 18.8-20.6, and a mean expected heterozygosity of 0.902-0.921. They were not reduced compared with those of their base population. Estimated effective population sizes based on temporal variances in microsatellite frequencies were smaller to that of sex ratio-corrected broodstock count estimates. Using a rela- tively large number ofbroodstock and keeping an equal sex ratio in the broodstock each generation may have contributed to retaining the original genetic diversity and maintaining relatively large effective population size. The results obtained in this study showed that the genetic variation was not affected greatly by mass selection progress and high genetic variation still existed in the mass selection lines, suggesting that there is still potential for increasing the gains in future generations of C. gigas. The present study provided im- portant information for future genetic improvement by selective breeding, and for the design of suitable management guidelines for genetic breeding of C. gigas. 展开更多
关键词 Pacific oyster genetic variation MICROSATELLITE mass selection line effective population size
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Thermal stresses around a circular inclusion with functionally graded interphase in a finite matrix 被引量:1
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作者 YANG QuanQuan GAO CunFa 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2014年第10期1927-1933,共7页
Based on the theory of the complex variable functions, the analysis of non-axisymmetric thermal stresses in a finite matrix containing a circular inclusion with functionally graded interphase is presented by means of ... Based on the theory of the complex variable functions, the analysis of non-axisymmetric thermal stresses in a finite matrix containing a circular inclusion with functionally graded interphase is presented by means of the least square boundary collocation technique. The distribution of thermal stress for the functionally graded interphase layer with arbitrary radial material parameters is derived by using the method of piece-wise homogeneous layers when the finite matrix is subjected to uniform heat flow. The effects of matrix size, interphase thickness and compositional gradient on the interfacial thermal stress are discussed in detail. Numerical results show that the magnitude and distribution of interfacial thermal stress in the inclusion and matrix can be designed properly by controlling these parameters. 展开更多
关键词 thermal stress functionally graded interphase INCLUSION finite matrix
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Linear and Nonlinear Optical Properties of Spherical Quantum Dots:Effects of Hydrogenic Impurity and Conduction Band Non-Parabolicity 被引量:4
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作者 G.Rezaei B.Vaseghi N.A.Doostimotlagh 《Communications in Theoretical Physics》 SCIE CAS CSCD 2012年第3期485-489,共5页
Simultaneous effects of an on-center hydrogenic impurity and band edge non-parabolicity on intersubband optical absorption coefficients and refractive index changes of a typical GaAs/AlxGa1-xAs spherical quantum dot a... Simultaneous effects of an on-center hydrogenic impurity and band edge non-parabolicity on intersubband optical absorption coefficients and refractive index changes of a typical GaAs/AlxGa1-xAs spherical quantum dot are theoretically investigated, using the Luttinger-Kohn effective mass equation. So, electronic structure and optical properties of the system are studied by means of the matrix diagonalization technique and compact density matrix approach, respectively. Finally, effects of an impurity, band edge non-parabolicity, incident light intensity and the dot size on the linear, the third-order nonlinear and the total optical absorption coemcients and refractive index changes are investigated. Our results indicate that, the magnitudes of these optical quantities increase and their peaks shift to higher energies as the influences of the impurity and the band edge non-parabolicity are considered. Moreover, incident light intensity and the dot size have considerable effects on the optical absorption coefficients and refractive index changes. 展开更多
关键词 hydrogenic impurity non-parabolic conduction band quantum dots absorption coefficient refractive index
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