基于Visual FoxPro中表复制技术的研究

表复制是国家计算机等级考试中常出现的考试内容.通过对VFP中多个命令的介绍,分别阐述了几种实现表复制的不同方法与技术.

TMS320C6000系列DSP的Flash引导研究

文中对TI公司的TMS320C6000系列DSP(数字信号处理器)的Flash引导方式进行了研究,详细阐述了DSP Flash引导模式的实现原理及引导过程,链接命令文件的编写,和如何实现基于第二Bootloader的Flash引导。在实际工程应用中,以TMS320C6202B型DSP和SST39VF800A型Flash为目标系统,根据实际使用经验,由浅入深,从简单到复杂,着重强调了C6X0X与其它C6000芯片在内部存储器结构上的不同而导致Flash引导上的差异,并编写了相应的汇编代码程序,成功实现了基于复制表的第二Bootloader Flash引导,系统运行稳定可靠,表明了该引导方法行之有效。

Excel行数据批量输出为Word样式文档

Excel行数据批量输出为Word样式文档步骤;VBA宏代码的简单应用。

HepG2 cells support viral replication and gene expression of hepatitis C virus genotype 4 in vitro

AIM： TO establish a cell culture system with longterm replication of hepatitis C virus （HCV） genome and expression of viral antigens in vitro. METHODS： HepG2 cell line was tested for its susceptibility to HCV by incubation with a serum from a patient with chronic hepatitis C. Cells and supernatant were harvested at various time points during the culture. Culture supernatant was tested for its ability to infect na＇ive cells. The presence of minus （antisense） RNA strand, and the detection of core and E1 antigens in cells were examined by RT-PCR and immunological techniques （flow cytometry and Western blot） respectively. RESULTS： The intracellular HCV RNA was first detected on d 3 after infection and then could be consistently detected in both cells and supernatant over a period of at least three months. The fresh cells could be infected with supernatant from cultured infected cells. Flow cytometric analysis showed surface and intracellular HCV antigen expression using in house made polyclonal antibodies （anti-core, and anti-E1）. Western blot analysis showed the expression of a cluster of immunogenic peptides at molecular weights extended between 31 and 45 kDa in an one month old culture of infected cells whereas this cluster was undetectable in uninfected HepG2 cells. CONCLUSION： HepG2 cell line is not only susceptible to HCV infection but also supports its replication in vitro. Expression of HCV structural proteins can be detected in infected HepG2 cells. These cells are also capable of shedding viral particles into culture media which in turn become infectious to uninfected cells.

Development and Characterization of West Nile Virus Replicon Expressing Secreted Gaussia Luciferase

We developed a Gaussia luciferase (Gluc) reporter replicon of West Nile virus (WNV) and used it to quantify viral translation and RNA replication. The advantage of the Gluc replicon is that Gaussia luciferase is secreted into the culture medium from cells transfected with Gluc replicon RNA, and the medium can be assayed directly for luciferase activity. Using a known Flavivirus inhibitor (NITD008), we demonstrated that the Gluc-WNV replicon could be used for antiviral screening. The Gluc-WNV-Rep will be useful for research in antiviral drug development programs, as well as for studying viral replication and pathogenesis of WNV.

A case-control study of the relationship between hepatitis B virus DNA level and risk of hepatocellular carcinoma in Qidong,China

AIM:To investigate the role of hepatitis B virus (HBV) replication in the development of hepatocellular carcinoma (HCC), a nested case-control study was performed to study the relationship between HBV DNA level and risk of HCC. METHODS:One hundred and seventy cases of HCC and 276 control subjects free of HCC and cirrhosis were selected for this study. Serum HBV DNA level was measured using fluorescein quantitative polymerase chain reaction at study entry and the last visit. RESULTS:In a binary unconditional logistic regression analysis adjusted for age, cigarette smoking, alcohol consumption and family history of chronic liver diseases, the adjusted odds ratios (95% confidence intervals) of HCC in patients with increasing HBV DNA level were 2.834 (1.237-6.492), 48.403 (14.392-162.789), 42.252 (14.784-120.750), and 14.819 (6.992-31.411) for HBV DNA levels ≥ 104 to < 105; ≥ 105 to < 106; ≥ 106 to < 107; ≥ 107 copies/mL, respectively. Forty-six HCC cases were selected to compare the serums viral loads of HBV DNA at study entry with those at the last visit. The HBV DNA levels measured at the two time points did not differ significantly.CONCLUSION:The findings of this study provide strong longitudinal evidence of an increased risk of HCC associated with persistent elevation of serum HBV DNA level in the 104-107 range.

Novel Evidence Suggests Hepatitis B Virus Surface Proteins Participate in Regulation of HBV Genome Replication

Naturally occurring mutations in surface proteins of Hepatitis B virus(HBV) usually result in altered hepatitis B surface antigen(HBsAg) secretion efficiency.In the present study,we reported two conserved residues,M75 and M103 with respect to HBsAg,mutations of which not only attenuated HBsAg secretion(M75 only),but also suppressed HBV genome replication without compromising the overlapping p-gene product.We also found M75 and M103 can initiate truncated surface protein(TSPs) synthesis upon over-expression of full-length surface proteins,which may possibly contribute to HBV genome replication.However,attempts to rescue replicationdefective HBV mutant by co-expression of TSPs initiated from M75 or M103 were unsuccessful,which indicated surface proteins rather than the putative TSPs were involved in regulation of HBV genome replication.

Different expression patterns of duplicated PHANTASTICA-like genes in Lotus japonicus suggest their divergent functions during compound leaf development

Recent studies on leaf development demonstrate that the mechanism on the adaxial-abaxial polarity pattern formation could be well conserved among the far-related species, in which PHANTASTICA （PAHN）-Iike genes play important roles. In this study, we explored the conservation and diversity on functions of PHAN-Iike genes during the compound leaf development in Lotusjaponicus, a papilionoid legume. Two PHAN-Iike genes in L. japonicus, LjPHANa and LjPHANb, were found to originate from a gene duplication event and displayed different expression patterns during compound leaf development. Two mutants, reduced leafletsl （rell） and reduced leaflets3 （rel3）, which exhibited decreased adaxial identity of leaflets and reduced leaflet initiation, were identified and investigated. The expression patterns of both LjPHANs in rel mutants were altered and correlated with abnormalities of compound leaves. Our data suggest that LjPHANa and LjPHANb play important but divergent roles in regulating adaxial-abaxial polarity of compound leaves in L. japonicus.

利用Delphi组件编程二例

通过两个实例 ,介绍了在 Delphi中数据库连接。

DNA-dependent activator of interferon-regulatory factors inhibits hepatitis B virus replication

AIM： To investigate whether DNA-dependent activator of interferon-regulatory factors （DAI） inhibits hepatitis B virus （HBV） replication and what the mechanism is. METHODS： After the human hepatoma cell line Huh7 was cotransfected with DAI and HBV expressing plas- mid, viral protein （HBV surface antigen and HBV e an- tigen） secretion was detected by enzyme-linked immu- nosorbent assay, and HBV RNA was analyzed by real- time polymerase chain reaction and Northern blotting, and viral DNA replicative intermediates were examined by Southern blotting. Interferon regulatory factor 3 （IRF3） phosphorylation and nuclear translocation were analyzed via Western blotting and immunofluorescence staining respectively. Nuclear factor-KB （NF-KB） activity induced by DAI was detected by immunofluorescence staining of P65 and dual luciferase reporter assay. Tran- swell co-culture experiment was performed in order to investigate whether the antiviral effects of DAI were dependent on the secreted cytokines. RESULTS： Viral protein secretion was significantly re- duced by 57% （P 〈 0.05）, and the level of total HBV RNA was reduced by 67% （P 〈 0.05）. The viral core particle-associated DNA was also dramatically down- regulated in DAI-expressing Huh7 cells. Analysis of involved signaling pathways revealed that activation of NF-KB signaling was essential for DAI to elicit antivi- ral response in Huh7 cells. When the NF-KB signaling pathway was blocked by a NF-KB signaling suppressor （I~：B^-SR）, the anti-HBV activity of DAI was remarkably abrogated. The inhibitory effect of DAI was indepen- dent of IRF3 signaling and secreted cytokines. CONCLUSION： This study demonstrates that DAI can inhibit HBV replication and the inhibitory effect is asso- ciated with activation of NF-KB but independent of IRF3 and secreted cytokines.

Preparation and Characterization of Sodium Sulfate/Silica Composite as a Shape-stabilized Phase Change Material by Sol-gel Method

A sodium sulfate （NaeSO4）/silica （SiO2） composite was prepared as a shape-stabilized solid-liquid phase change material by a sol-gel procedure using Na2SiO3 as the silica source. Na2SO4 in the composite acts as a latent heat storage substance for solid-liquid phase change, while SiO2 acts as a support material to provide structural strength and prevent leakage of melted NazSO4. The microstructure and composition of the prepared composite were characterized by the N2 adsorption, transmission electron microscope （TEM）, scanning electron microscope （SEM）, Fourier transform infrared spectroscopy （FTIR） and X-ray diffraction. The results show that the prepared Na2SOJSiO2 composite is a nanostructured hybrid of NazSO4 and SiO2 without new substances produced during the phase change. The macroscopic shape of the NazSO4/SiO2 composite after the melting and freezing cycles does not change and there is no leakage of Na2SO4. Determined by differential scanning calorimeter （DSC） analysis, the values of phase change latent heat of melting and freezing of the prepared NazSO4/SiO2 （50%, by mass） composite are 82.3 kJ.kg i and 83.7 kJ.kg-1, and temperatures of melting and freezing are 886.0 ℃ and 880.6 ℃, respectively. Furthermore, the Na2SOJSiO2 composite maintains good thermal energy storage and release ability even after 100 cycles of melting and freezing. The satisfactory thermal storage performance renders this composite a versatile tool for high-temperature thermal energy storage.

Preparation, characterization and salt-resistance of a coal based super absorbent composite

Potassium humate was extracted from brown coal. A novel super absorbent composite, poly （acrylic acid-co-acryla- mide）/potassium humate （PAA-AM/KHA）, was prepared by graft polymerization of acrylic acid, acrylamide and coal based potassium humate using N, N＇-methylenebisacrylamide as a crosslinker and potassium peroxydisulfate as an initiator. The effects of reaction temperature, degree of neutralization of the poly （acrylic acid） and the amounts of crosslinker, initiator and potassium humate were investigated. Salt resistance tests were also carded out. The composite prepared under optimal conditions had a potassium bumate content of 10% and exhibited a water absorption of 770 g/g in distilled water, and 349, 286 and 41 gig in 0.5 mol/L KC1, MgC12 and A1CI3 solutions respectively. The results indicate that the salt resistance of PAA-AM/KHA was superior to that of poly （acrylic acid-co-acrylamide） because of the collaborative effect of functional groups of the coal based potassium humate. The PAA-AM/KHA micro powder was characterized by IR spectroscopy and the micrographic surface was characterized by scanning electron microscopy. Introduction of potassium humate into the poly （acrylic acid-co-acrylamide） structure creates a composite more suitable for use as a water-managing material in the renewal of arid and desert environments. The salt resisting property of the composite is improved, production costs are reduced and the growth stimulant effect is still present.

Fabrication of cast carbon steel with ultrafine TiC particles

The carbon steels dispersed with ultrafine TiC particles were fabricated by conventional casting method. The casting process is more economical than other available routes for metal matrix composite production, and the large sized components to be fabricated in short processing time. However, it is extremely difficult to obtain uniform dispersion of ultrafine ceramic particles in liquid metals due to the poor wettability and the specific gravity difference between the ceramic particle and metal matrix. In order to solve these problems, the mechanical milling (MM) and surface-active processes were introduced. As a result, Cu coated ultrafine TiC powders made by MM process using high energy ball milling machine were mixed with Sn powders as a surfactant to get better wettability by lowering the surface tension of carbon steel melt. The microstructural investigations by OM show that ultrafine TiC particles are distributed uniformly in carbon steel matrix. The grain sizes of the cast matrix with ultrafine TiC particles are much smaller than those without ultrafine TiC particles. This is probably due to the fact that TiC particles act as nucleation sites during solidification. The wear resistance of cast carbon steel composites added with MMed TiC/Cu-Sn powders is improved due to grain size refinement.

VolGraph-A PC-Based Visualization System for Three-Dimensional Medical Reconstructions

Three-dimensional reconstructions from tomography slices are paid great attention in medical applications nowadays. This paper introduces the design and the implement of VolGraph system: a new, inexpensive, PC-based visualization tool for three-dimensional medical reconstructions, which fully integrates the latest popular visualization algorithms ranging from classical surface rendering algorithm to volume rendering algorithms, such as Ray Casting, Splatting, and Shear-Warp.The input of VolGraph can be medical ima- ges including CT, MRI, etc, and the output can be in common image, VRML/XML or animation formats. Practice proves that the realization of a medical volume visualization system is now feasible on desktop PCs.

Preparation and characterization of Mo-Cu nanocomposite powders by chemical liquid reduction process

A novel chemical liquid reduction process was employed to prepare nanosized Mo-Cu powders. The precipitates were first obtained by adding ammonium heptamolybdate （（NH4）6Mo7024·4H2O） solution into excess hydrazine hydrate solution, and then mixed the copper chloride solution. The precipitates were subsequently washed, dried, followed by reducing in H2 atmosphere to convert into Mo-Cu composite powders. The composition, morphology and particle size of the Mo-Cu composite powders were characterized by the XRD, SEM and TEM. The effects of the chemical reaction temperature and the magnetic stirring on the morphology of the Mo-Cu powders were also studied. The results show that Mo-Cu powders produced by the chemical liquid reduction process are nearly spherical shape and dispersive distribution state, with particle size ranging from 50 to 100 nm. The chemical reaction temperature and magnetic stirring will change the particle feature of the powders. Because of the Cu3M0209, the reduction process in H2 is the one-stage reduction from the precipitates to the Mo-Cu composite powders.

Preparation and characterization of chitosan/nano-hydroxyapatite composite used as bone substitute materials

Chitosan/nano-hydroxyapatite composites with different weight ratios were prepared through a co-precipitation method using Ca（OH）2, H3PO4 and chitosan as starting materials. The properties of these composites were characterized by means of TEM, IR, XRD, TGA, burn-out tests and universal matertial testing machine. The results showed that the HA synthesized here was poorly crystalline carbonated nanometer crystals and dispersed uniformly in chitosan phase and there was no phase-separation between the two phases. The addition of n-HA resulted in a decrease of decomposing temperature of chitosan. Because of the interactions between chitosan and n-HA, the mechanical properties of these composites were improved, and the maximum value of the compressive strength was measured to be about 120MPa corresponding to the chitosan/n-HA composite with a weight ratio of 30/70.

Microstructure and wear performance of Al5083/CeO_2/SiC mono and hybrid surface composites fabricated by friction stir processing

Friction stir processing（FSP） was utilized to produce surface composites by incorporating nano-sized cerium oxide（CeO2） and silicon carbide（SiC） particles individually and in combined form into the Al5083 alloy matrix. The study signified the role of these reinforcements on microstructure and wear behavior of the resultant surface composite layers. The wear characteristics of the resultant mono and hybrid surface composite layers were investigated using a pin-on-disc wear tester at room temperature. The microstructural observations of FSPed regions and the worn out surfaces were performed by optical and scanning electron microscopy. Considerable grain refinement and uniform distribution of reinforcement particles were achieved inside the nugget zone. All the composite samples showed higher hardness and wear resistance compared to the base metal. Among the composite samples, the hybrid composite（Al5083/CeO2/SiC） revealed the highest wear resistance and the lowest friction coefficient, whereas the Al5083/SiC composite exhibited the highest hardness, i.e., 1.5 times as hard as that of the Al5083 base metal. The enhancement in wear behavior of the hybrid composites was attributed to the solid lubrication effect provided by CeO2 particles. The predominant wear mechanism was identified as severe adhesive in non-composite samples, which changed to abrasive wear and delamination in the presence of reinforcing particles.

Construction of non-replicating recombinant vaccinia virus expressing HPV16 L1,L2E7 proteins

Objective： To construct a non-replicating vaccinia virus expressing human papillomavirus 16 （HPV16） L1, L2E7 proteins as a candidate vaccine for cervical cancer. Methods： Using vaccinia virus vector, we generated a strain of non-replicating recombinant vaccinia virus vaccine expressing HPV16 L1, L2E7 proteins by homologous recombination and identified by PCR and Westernloting. Results： We demonstrated that the L1, L2E7 gene of HPV16 were integrated into vaccinia genosome and could express L1, L2E7 protein stably when infected the CEF using PCR and Western-blot assay. Conclusion： NTVJL1/L2E7 can express L1, L2E7 protein of HPV16 and can be taken as a candidate vaccine for HPV16-associated diseases.

Fabrication and characterization of composite YSZ-La_(9.33)Si_6O_(26) oxygen-ion conductor

To improve the conductivity of Y2O3-stabilized ZrO2 （YSZ） based oxygen-ion conductor, Zr0.85Y0.15O1.925-La9.33Si6O26 （YSZ-LSO） composite ceramics with the mass fraction of La9.33Si6O26 （LSO） of 15% were prepared by using a modified coprecipitation method. The phases, microstructures and conductivities of the YSZ, LSO and YSZ-LSO were investigated by X-ray diffraction, electron microscopy and complex impedance, respectively. The results show that the as-calcined powder of YSZ-LSO composite has the grain size less than 10 nm, and the as-sintered composite ceramics are composed of YSZ and LSO phases. The conductivity can be enhanced obviously by composite method. At 700 ℃, the conductivity of the composite ceramic is 0.125 S/cm, which is one order in magnitude higher than that of the YSZ ceramic and two orders in magnitude higher than that of LSO ceramic. By analyzing the impedance spectra and modulus spectra, the interfacial effect on the conductivity improvement was proposed.