Characterization of a new type HPV16 E7 variant isolated from cervical cancer highest incidence area in Hubei Province of China

AIM: To investigate the variation and biological properties of HPV16 E7 isolated from cervical cancer biopsy samples from highest incidence area in HuBei province of China. METHODS: HVP16 E7 sequences isolated from the cervical cancer biopsies of 10 local patients were amplified, sequenced and compared with prototype E7 gene. Then the variant gene was cloned into different vectors to study the antigenicity, expression and immunogenicity of its protein by Western blot, immunofluorescence and genetic immunization in vitro or in vivo. RESULTS: The results showed that 7 of 10 samples had the same mutations which led to a nonsense mutation at codon 43 of E7 sequence. The truncated E7 protein could be recognized by standard E7 monoclonal antibody in Western blot and expressed in NIH3T3 cells. In the blood sera of mice immunized intramuscularly by the plasmid DNA expressing the variant E7 gene specific E7 antibodies could be detected at week 2, 3, 5 and 6 after inoculation. However, no specific lymphoproliferation after E7 protein stimulation in vitro was detected by MTT colorimetric assay in comparison to the prototype E7 protein. CONCLUSION: HPV16 E7 gene may show variation in China and the variant protein could be expressed and induce host humoral immune response, but could not elicit special cellular-immune response against it. These data might hold the key for future development of HPV16 vaccine in HuBei province of China.     

The biomechanics of lumbar graded facetectomy under anterior-shear load

In this paper, an anatomically accurate three-dimensional finite-element (FE) model of the human lumbar spine (L2-L3) was used to study the biomechanical effects of graded bilateral and unilateral facetectomies of L3 under anterior shear. The intact L2-L3 FE model was validated under compression, tension, and shear loading and the predicted responses matched well with experimental data. The gross external (translational and coupled) responses, flexibilities, and facet load were delineated for these iatrogenic changes. Results indicted that unilateral facetectomy of greater than 75% and bilateral facetectomy of 75% or more resection markedly alter the translational displacement and flexibilities of the motion segment. This study suggests that fixation or fusion to restore strength and stability of the lumbar spine may be required for surgical intervention of greater than 75% facetectomy.     

Capillary electrophoresis coupled with electrochemiluminescence detection using porous etched joint

A new setup to couple capillary electrophoresis (CE) with electrochemiluminescence (ECL) detection is described in which the electrical connection of CE is achieved through a porous section at a distance of 7 mm from the CE capillary outlet. Because the porous capillary wall allowed the CE current to pass through and there was no electric field gradient beyond that section, the influence of CE high-voltage field on the ECL procedure was eliminated. The porous section formed by etching the capillary with hydrofluoric acid after only one side of the circumference of 2-3 mm of polyimide coating of the capillary was removed, while keeping the polyimide coating on the other part to protect the capillary from HF etching makes the capillary joint much more robust since only a part of the circumference of it is etched. A standard three-electrode configuration was used in experiments with Pt wire as a counter electrode, Ag/AgCl as a reference electrode, and a 300-microm diameter Pt disk as a working electrode. Compared with CE-ECL conventional decoupler designs, the present setup with a porous joint has no added dead volume created. Moreover, the dead volume can be increasingly decreased by shortening the distance ( approximately 100 microm) between the working electrode and the end of the separation capillary. The versatility in choice of capillaries and separation buffers within this design is the main advantage over the use of small i.d. capillary and low conductivity buffer in some CE-ECL systems. The performance of this setup is illustrated by the analyses of tripropylamine and proline.     

Proposal and testing of dual-beam dynamic light scattering for two-particle microrheology

A dual-beam dynamic light-scattering arrangement is devised to measure the time-dependent mean squared relative displacement of a pair of tracer particles with a small separation of micrometers. The technique is tested by the measurement of the relative diffusion of polymer latex spheres suspended in a simple viscous fluid. The experiment verifies the theory and demonstrates its applications. The dual-beam dynamic light-scattering technique, when combined with an optical microscope, provides a powerful tool for the study of two-particle microrheology of soft materials. The advantages of the new technique are its high statistical accuracy, faster temporal response, and ease of use.     

Study on novel second-order NLO azo-based chromophores containing strong electron-withdrawing groups and different conjugated bridges

Novel NLO azo-based chromophores containing strong electron-withdrawing groups and benzene or thiazole moiety as conjugated bridges were synthesized and characterized. values were measured by HRS method, they are in the range of 238–1459 × 10^–30 esu at the fundamental wavelength of 800 nm. For chromopheres 3 and 4, values at the fundamental wavelength of 1064 nm were also measured, they are 1575 × 10^–30 esu and 935 × 10^–30 esu, respectively. Thermal stabilities for these chromophores are reported. We also discuss the effects of different acceptors and conjugating moieties on .     

不同支付函数形式对MG模型行为的影响

MG是描述多个体竞争性系统的一个结构简单但行为复杂的模型。MG模型的一个重要的机制是支付函数,它决定了对模型主体的财富和主体的策略的更新规则。该文研究了不同支付函数形式对模型的影响,发现支付函数只要是奖励赢方(少数方),惩罚输方(多数方),模型的突现行为就不会改变,与奖惩的具体形式无关,同时还发现模型突现行为有两个必要条件,一是主体必须竞争有限资源,二是在竞争中必须规定“拥挤效应”。     

Lattice-based flow field modeling

We present an approach for simulating the natural dynamics that emerge from the interaction between a flow field and immersed objects. We model the flow field using the lattice Boltzmann model (LBM) with boundary conditions appropriate for moving objects and accelerate the computation on commodity graphics hardware (GPU) to achieve real-time performance. The boundary conditions mediate the exchange of momentum between the flow field and the moving objects resulting in forces exerted by the flow on the objects as well as the back-coupling on the flow. We demonstrate our approach using soap bubbles and a feather. The soap bubbles illustrate Fresnel reflection, reveal the dynamics of the unseen flow field in which they travel, and display spherical harmonics in their undulations. Our simulation allows the user to directly interact with the flow field to influence the dynamics in real time. The free feather flutters and gyrates in response to lift and drag forces created by its motion relative to the flow. Vortices are created as the free feather falls in an otherwise quiescent flow.     

Analysis of symmetric or partially symmetric structures

This paper combines group-theoretic methods with substructuring techniques to treat the symmetric or partially symmetric structures subjected to arbitrary loads. First, for a given substructure module, whose symmetry group is G, it gives a method to find the generalized displacements associated with irreducible representations of G based on some concepts presented in this paper, and then points out that for these displacements the analysis problem for a substructure module can be divided into a series of uncoupled subproblems. For each subproblem the triangularization as well as condensation can be carried out individually. Finally a simplified calculation formula of condensed stiffness coefficients for the original displacements is established, in which only the coefficients relating to the displacements in the basic region are necessary to be calculated.A series of computer programs has been developed by the methods presented in this paper [1–4]. These programs enable us to reduce the CPU time and save the memory noticeably.     

Theory of tunable FIR laser

Tunable properties of optically pumped FIR lasers have been studied on the basis of sixlevel quantum system approach. The signal flow graph method was used to solve the density matrix equations. A set of tuning characteristic curves has been obtained in good agreement with the experimental results for optically pumped HF FIR lasers given by A. de Martino et al.     

Carbon nanotubes as assisted matrix for laser desorption/ionization time-of-flight mass spectrometry

Analysis of low molecular weight compounds with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) has been developed by using carbon nanotubes obtained from coal by arc discharge as the matrix. The carbon nanotube matrix functions as substrate to trap analytes of peptides, organic compounds, and beta-cyclodextrin deposited on its surface. It has been found that carbon nanotubes can transfer energy to the analyte under laser irradiation, which makes analytes well desorbed/ionized, and the interference of intrinsic matrix ions can be eliminated. At the same time, the fragmentation of the analyte can be avoided. A good sensitivity and excellent reproducibility of the spectrum signals are achieved. It is believed that this work not only will open a new field for applications of carbon nanotubes, but also will offer a new technique for high-speed analysis of low molecular weight compounds in areas such as metabolism research and characterization of natural products.