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1.
Human serum albumin(HSA) is widely utilized for medical purposes and biochemical research.Transgenic rice has proved to be an attractive bioreactor for mass production of recombinant HSA(rHSA).However,transgene spread is a major environmental and food safety concern for transgenic rice expressing proteins of medical value.This study aimed to develop a selectively terminable transgenic rice line expressing HSA in rice seeds,and a simple process for recovery and purification of rHSA for economical manufacture.An HSA expression cassette was inserted into a T-DNA vector encoding an RNA interference(RNAi) cassette suppressing the CYP81A6 gene.This gene detoxifies the herbicide bentazon and is linked to the 5-enolpyruvylshikimate-3-phosphate synthase(EPSPS) cassette which confers glyphosate tolerance.ANX Sepharose Fast Flow(ANX FF) anion exchange chromatography coupled with Butyl Sepharose High Performance(Butyl HP) hydrophobic interaction chromatography was used to purify rHSA.A transgenic rice line,HSA-84,was obtained with stable expression of rHSA of up to 0.72% of the total dry weight of the dehusked rice seeds.This line also demonstrated high sensitivity to bentazon,and thus could be killed selectively by a spray of bentazon.A two-step chromatography purification scheme was established to purify the rHSA from rice seeds to a purity of 99% with a recovery of 62.4%.Results from mass spectrometry and N-terminus sequencing suggested that the purified rHSA was identical to natural plasma-derived HSA.This study provides an alternative strategy for large-scale production of HSA with a built-in transgene safety control mechanism.  相似文献   

2.
Sapir-Whorf Hypothesis (SWH) is a great contribution to the study of the relationship between language and thought. This paper, with a dialectic view, aims to do some analyses to the SWH and arouse the...  相似文献   

3.
INTRODUCTION An important problem in foundation engineeringis the determination of the rate of settlement of a raftfoundation placed on a deep clay layer. Gibson andMcNamee (1957), and McNamee and Gibson (1960a;1960b) considered the problem of normal uniformloading applied to the surface of a half-space andshowed that one-dimensional theory gives a markedunderestimate of the rate of settlement. This theorycorresponds to the case of a perfectly flexible footing.However, it is often…  相似文献   

4.
Implementing VLPR systems based on TMS320DM642   总被引：1，自引：0，他引：1  
This paper gives a practical schema for using DSP boards to construct Vehicle License Plate Recognition (VLPR) modules that could be embedded in any Intelligent Transportation System (ITS). Using DSP can avoid the heavy investment in dedicated VLPR system and improve the computational power compared to PC software environment. Low cost, high computational power, and high flexibility of DSP provide the License Plate Recognition System (LPRS) an excellent cost-effective solution to execute the major part of the recognition tasks. This paper describes a successful implementation of VLPR system based on Texas Instruments (TI)'s TMS320DM642. The DSP board acquires video (which could be output to a monitor for surveillance) from a camera, captures images from the video, locates and recognizes the license plates in images, and then sends the recognized results and related images after compression to a host PC through the network. Finally, the overall software is optimized according to the features of DM642 chip. Experiments showed that the DSP VLPR system performs well on the local license plates, and that the processing speed and accuracy can meet the requirement of practical applications.  相似文献   

5.
雷春晓 《海外英语》2015,(2):105-106
Code-switching is an important domain in the sociolingusitics. Since the 1970 s, lots of linguists and experts has attached great importance to it. This paper is a tentative study of code-switching in the teaching English as a second language(TESL) from such aspects: the review of code-switching, principles adhered to the code-switching, factors which leads to the code-switching, and attitudes and functions of code-switching in the TESL.  相似文献   

6.
This paper explores the application of term dependency in information retrieval (IR) and proposes a novel dependency retrieval model. This retrieval model suggests an extension to the existing language modeling (LM) approach to IR by introducing dependency models for both query and document. Relevance between document and query is then evaluated by reference to the Kullback-Leibler divergence between their dependency models. This paper introduces a novel hybrid dependency structure, which allows integration of various forms of dependency within a single framework. A pseudo relevance feedback based method is also introduced for constructing query dependency model. The basic idea is to use query-relevant top-ranking sentences extracted from the top documents at retrieval time as the augmented representation of query, from which the relationships between query terms are identified. A Markov Random Field (MRF) based approach is presented to ensure the relevance of the extracted sentences, which utilizes the association features between query terms within a sentence to evaluate the relevance of each sentence. This dependency retrieval model was compared with other traditional retrieval models. Experiments indicated that it produces significant improvements in retrieval effectiveness.  相似文献   

7.
The protein encoded by CC chemokine receptor 7 (CCR7) is a member of the G protein-coupled receptor family. This receptor was identified as a gene induced by the Epstein-Barr virus (EBV), and is thought to be a mediator of EBV effects on B lymphocytes. This receptor is expressed in various lymphoid tissues and activates B and T lymphocytes. It has been shown to control the migration of memory T cells to inflamed tissues, as well as stimulate dendritic cell maturation. To map the CCR7 gene in chicken chromosome, a 6 000 rads chicken-hamster radiation hybrid panel (ChickRH6) was used. PCR of samples from ChickRH6 revealed that the location of CCR7 gene is linked to the maker SEQ0347 (6 cR away) with LOD score of 16.6 and that the marker SEQ0347 is located on chromosome 27 at 27 cR of RH (radiation hydrid) map. We compared the corresponding human mRNA sequence with the predicted coding sequence of chicken CCR7 gene, and found that the assembled contig shared a high percentage of similarity with that of the human gene.  相似文献   

8.
The dynamic characteristics and failure modes of steel reinforced concrete (SRC) columns subjected to blast loading are complicated because of the transient stress wave in the SRC columns and the interaction between steel and concrete. This paper presents a numerical simulation of the response of SRC columns subjected to blast loading using hydrocode LS-DYNA. In the numerical model, a sophisticate concrete material model (the Concrete Damage Model) is employed with consideration of the strain rate effect and the damage accumulation. An erosion technique is adopted to model the spalling process of concrete. The possible failure modes of SRC columns are evaluated. It is observed that the failure of SRC columns subjected to blast load can generally be classified into three modes, namely, a direct failure in concrete body due to the stress wave, a transverse shear failure near the support sections due to the high shear force, and a flexural failure pertaining to large local and global deformation of the reinforcing steel.  相似文献   

9.
The more unambiguous statement of the P versus NP problem and the judgement of its hardness, are the key ways to find the full proof of the P versus NP problem. There are two sub-problems in the P versus NP problem. The first is the classifications of different mathematical problems (languages), and the second is the distinction between a non-deterministic Turing machine (NTM) and a deterministic Turing machine (DTM). The process of an NTM can be a power set of the corresponding DTM, which proves that the states of an NTM can be a power set of the corresponding DTM. If combining this viewpoint with Cantor’s theorem, it is shown that an NTM is not equipotent to a DTM. This means that "generating the power set P(A) of a set A" is a non-canonical example to support that P is not equal to NP.  相似文献   

10.
YE Yi 《海外英语》2014,(9):23-28
This paper is based on three observations and independent thinking of the classroom teaching of the author’s colleagues.It attempts to examine how macro and micro contexts affect teaching and learning in the classroom.The author focuses the discussion on three aspects:(i)the present EFL contextual setting in China;(ii)the influence of the evaluation system on both teachers and students;(iii)his own beliefs as a teacher.Finally,he comes to the implications that teachers should often reflect on their teaching by means of observing other teachers’teachings;In order to bring more effective teaching and learning to the class,Teachers should change their class from a teacher-centered one to a students-centered one.  相似文献   

11.
INTRODUCTION The concept of left-handed materials (LHM for short, also called negative index materials) was in- troduced by Veselago (1968). An LHM has both negative permittivity and negative permeability, which makes the wave vector, the electric-field vector, and the magnetic-field vector in the LHM obey the left-hand rule. Experimental verifications for the existence of an LHM were made and its use as a perfect lens was suggested (Pendry, 2000; Shelby et al., 2001a; 2001b; Smith …  相似文献   

12.
INTRODUCTION Veselago (1968) showed that if both the permit- tivity ε and the magnetic permeability μ of a material are negative, the propagation direction of an elec- tromagnetic (EM) wave will be opposite to its energy flow direction. Such media are called left-handed materials (LHMs) since the electric field E, magnetic field H, and wave vector k in these media form a left-hand triplet of vectors, instead of a right-hand triplet observed in conventional materials. For a long time, …  相似文献   

13.
WeconsidertheKuramoto-Sivashinsky(K-S)equationinonespacedimensionwithperiodicboundaryconditionalldzero1lleantwhere110(x)isl-periodicandofzero"lean.TheK-Sequationmodelspatternformationsindifferentphysicalcontexts["3"landisaparadignloflowdimensionalbehaviou…  相似文献   

14.
In this paper, an integrated validation method and process are developed for multivariate dynamic systems. The principal component analysis approach is used to address multivariate correlation and dimensionality reduction, the dynamic time warping and correlation coefficient are used for error assessment, and the subject matter experts (SMEs)’ opinions and principal component analysis coefficients are incorporated to provide the overall rating of the dynamic system. The proposed method and process are successfully demonstrated through a vehicle dynamic system problem.  相似文献   

15.
INTRODUCTION At this moment, novel concepts of “negative” media, having negative refraction and/or “double negativity” and their physical consequences and plausible applications are drawing considerable at- tention from the science and engineering community. In the past few years, considerable progress has been made in electromagnetic (EM) waves. It is our wish to generalize such concepts to acoustic waves. Since the concept of negative refraction, negative constitutive relationships…  相似文献   

16.
This paper seeks to explore the notion of risk as an organisational logic within schools, the impact of contemporary accountability regimes on managing risk and then, in turn, to posit a systems-based process of risk management underpinned by a positive logic of risk. It moves through a number of steps beginning with the development of an understanding of risk, the risk society and the logic of risk derived from the seminal work of Douglas (1992, Risk and blame: essays in cultural theory, London: Sage), Beck (1992, Risk society: towards a new modernity. London: Sage) and Giddens (1990, The consequences of modernity. Cambridge: Polity Press). Second, the paper juxtaposes this understanding of risk with the rise of accountability imperatives and an “audit culture” [Strathern (1997) European Review, 5(3), 305–321] in public institutions, including schools. It then moves to consider how a systems-based approach to risk management, drawing on Reason’s (1990, Human Error. New York: Cambridge University Press) model of human error minimisation, could be usefully developed for schools. Such an approach would be built on a positive risk logic which maintains the flexibility, innovativeness and adaptability so necessary in education and avoids the more deleterious effects of many current forms of accountability and risk management which reflect avoidance, conformity and rigidity.  相似文献   

17.
The 21st century as a digital age is characterized by the increased accessibility of information and knowledge through the medium of sophisticated technological tools. The main aim of this article is to show how educational technology can be used effectively to help students construct knowledge when teaching Islamic studies in the UK. The first part of this paper summarizes the differences between information sharing and knowledge construction with reference to the essence of knowledge as Aristotelian ‘episteme’ (theoretical knowledge) and technê (practical knowledge: know-how); and the extent which the former process is created by the use of Information Technology (IT) while the latter is enhanced by Educational Technology (ET). The second part explores how ET can be used effectively to ‘provide training in critical and creative thinking skills of students’ as an integral part of producing useful tools and generating practical benefit during their learning process (Felder et al. 2000, p. 26; Callaos 2009, p. 3). The third, then, explains why a student centred and research-based teaching is preferred to traditional research-led method in order to support the construction of knowledge. The paper concludes by presenting some reflections and limitations on how effective use of ET and research-based teaching can help students to become critical thinkers while studying Islam and Middle Eastern politics as part of international politics curriculum in the UK.  相似文献   

18.
In this paper, we consider the detection and calculation of bifurcation from nontrivial steady-state solutions to ro~ wave solutions of the Kttramoto-Sivashinsky（K-S） equation by using the nonlinear Galerkin method. Numerical results show the efficiency and advantages of the nonlinear Galerkin method over the conventional Galerkin method in this application.  相似文献   

19.
This study is concerned with the challenge of understanding what factors may influence students’ higher level knowledge construction. We defined higher level knowledge construction occurrences as the sum of the number of phases II to V measured using Gunawardena et al.’s (J Educ Comput Res 17(4):397–431, 1997) interaction analysis model. This paper is organized into two studies. In the first study, we examined the relationship between the frequency of higher level knowledge construction occurrences and group size, as well as the duration of the online discussion. Data were collected through online observations of 40 discussion forums. We found a significant positive relationship between group size and the frequency of higher level knowledge construction occurrences. However, there was no correlation between the duration of the online discussion and the frequency of such occurrences. In the second study, we examined the types of student facilitation techniques used. A further analysis of the data was conducted—of the 40 forums, 14 forums with higher incident rate of higher level knowledge construction occurrences were identified. Fourteen less frequent forums were then randomly chosen from the remaining forums. We found significant differences in the frequency of four student facilitation techniques employed between the more frequent group and the less frequent one. The results of this study suggest that using these four techniques more frequently may promote knowledge construction in asynchronous online discussions.  相似文献   

20.
With the rapid development of highway construction and formation of the highway network in China,the man- agement of pavement maintenance and rehabilitation （MR） activities has become important.In this paper,four discrete optimization models are proposed for different parties involved in the management system： government,highway agent,con- tractor and the common users.These four optimal decision models are formulated as linear integer programming problems with binary decision variables.The objective function and constraints are based on the pavement performance and prediction model using the pavement condition index （PCI）.Numerical experiments are carried out with the data from a highway system in Sichuan Province which show the feasibility and effectiveness of the proposed models.  相似文献   

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