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   Science & Technology Review
2010, Vol.28, No. 19
13 October 2010

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The Technique of Magnetic Induction Hyperthermia——A Hope and Opportunity for Innovative Meditech in China

Science & Technology Review. 2010, 28 (19): 3-3. ;  doi:
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Abstract ( 348 )
特别栏目

Science & Technology Review. 2010, 28 (19): 8-8. ;  doi:
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Science & Technology Review. 2010, 28 (19): 10-10. ;  doi:
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Science & Technology Review. 2010, 28 (19): 14-15. ;  doi:
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Science & Technology Review. 2010, 28 (19): 16-17. ;  doi:
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Science & Technology Review. 2010, 28 (19): 18-19. ;  doi:
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Science & Technology Review. 2010, 28 (19): 127-127. ;  doi:
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Science & Technology Review. 2010, 28 (19): 140-140. ;  doi:
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Abstract ( 337 )
封面图片说明

Science & Technology Review. 2010, 28 (19): 8-8. ;  doi:
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Abstract ( 314 )
半月科技风云

Science & Technology Review. 2010, 28 (19): 9-9. ;  doi:
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Abstract ( 377 )
科技事件

Science & Technology Review. 2010, 28 (19): 11-11. ;  doi:
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Abstract ( 312 )
科技评论

Science & Technology Review. 2010, 28 (19): 12-12. ;  doi:
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Science & Technology Review. 2010, 28 (19): 122-122. ;  doi:
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Science & Technology Review. 2010, 28 (19): 123-123. ;  doi:
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Science & Technology Review. 2010, 28 (19): 124-124. ;  doi:
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Science & Technology Review. 2010, 28 (19): 125-125. ;  doi:
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Science & Technology Review. 2010, 28 (19): 126-126. ;  doi:
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Abstract ( 366 )

Science & Technology Review. 2010, 28 (19): 128-128. ;  doi:
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科技工作者建议

Science & Technology Review. 2010, 28 (19): 13-13. ;  doi:
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Abstract ( 329 )
Reviews

Science & Technology Review. 2010, 28 (19): 20-20. ;  doi:
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Abstract ( 332 )

Research Development for the Fabrication of Inorganic Continuous Mullite Fiber

Science & Technology Review. 2010, 28 (19): 93-97. ;  doi:
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Abstract ( 412 )
Inorganic continuous mullite fiber is a widely-used high-temperature ceramic material. It is used as an insulation material, a high temperature structure material, and a reinforcement fiber, because of its excellent thermal stability, chemical stability, and high-temperature mechanical strength. The complexity of processing and numerous other factors pose difficulties for the fabrication of the continuous mullite fiber. The preparation of continuous mullite fiber has been mastered by some foreign companies in the United States and Japan, and lucrative commercial products were made available. China still focuses on the production of short mullite fiber with little added value instead of the continuous fiber. In this paper, the merits and drawbacks of preparation methods of continuous mullite fiber are introduced, including sol-gel, electrospun, extrusion processes and the melting method. Recent progress in this field, both international and domestic, is summarized. Dry-spinning preparation via the sol-gel method is illustrated, and two technical routes, namely, the metal inorganic salt sol-gel and metal alkoxide sol-gel methods, are introduced. The structure and stability of the solution and the effects of spinning additives are discussed. Finally, the development prospects of the sol-gel method are presented.

Vulnerability to Heat Waves and Adaptation: A Summary

Science & Technology Review. 2010, 28 (19): 98-102. ;  doi:
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Abstract ( 479 )
An increase in the frequency and intensity of heat waves is likely to be one effect of global climate change, one which will attract the attention of the broader scientific community. Heat waves have serious impacts on society including probable increases in mortality, strain on infrastructure (power, water and transport) and social disturbance. Wider impacts may include effects on industries, tourism and ecosystems. To date, heat largely has been ignored. To develop better coping strategies, this paper explores the main factors that shape vulnerability to heat waves, the definition of heat waves and initiates an avenue of research to address considerable knowledge gaps in this area. Vulnerability to heat waves includes degree of exposure to the heat hazard, sensitivity to changes in weather/climate and adaptive capacity. Furthermore, based on a broad range of research, this paper outlines some suggestions to decrease the impact of heat waves and explores coping strategies for extreme events in the future. Heat waves do not affect everyone. The most likely to suffer are vulnerable individuals or sectors of society such as those who are elderly, have pre-existing health problems, work in jobs requiring heavy labor, live alone, are immobile or have a low-income. The synergistic effects of such factors may prove fatal for some. Adapting to more frequent heat waves should include soft engineering options and, where possible, avoidance of widespread use of air conditioning, which could prove unsustainable in terms of energy. Strategies for coping with heat include changing the way in which urban areas are developed or re-developed, and setting up heat watch warning systems that integrate weather forecast information with heat warnings and associated intervention strategies.

Medical Applications of Polylactic Acid: Recent Advances in Research

Science & Technology Review. 2010, 28 (19): 103-107. ;  doi:
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Abstract ( 490 )
Polylactic acid is an aliphatic polyester with excellent biocompatibility, biodegradability and bioabsorbability, and has been extensively applied in biomaterials. The principal raw material, lactic acid, is derived from corn and other natural materials. It is non-irritating and has no toxic effects, and is thus safe for human use. Because of its biodegradability, it is also environmentally friendly. Polylactic acid shows high plasticity and is easy to form, and is considered to be the most promising biomedical and packaging material. The mechanical, thermal and degradation properties of polylactic acid are improved by modifications. It is thus suitable for application as a modern biomedical material and has been widely used in various applications. In the present paper, we discuss recent advances in the medical applications of polylactic acid, including its use in resorbable medical sutures, dental materials, ophthalmic implant materials, fracture fixation devices, tissue engineering, delayed release drug carriers and clinical applications. Finally, we discuss the future prospects for the research and application of polylactic acid biodegradable materials. This paper also provides effective information to help researchers develop new medical materials to overcome the current limitations of polylactic acid-based materials.

Science & Technology Review. 2010, 28 (19): 118-118. ;  doi:
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Abstract ( 291 )

Science & Technology Review. 2010, 28 (19): 118-118. ;  doi:
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Abstract ( 286 )
Articles

Identification and Distribution of Intercalated Strata in the Triassic Petroleum Reservoir of the 9th Area, Tahe Oilfield

Science & Technology Review. 2010, 28 (19): 21-25. ;  doi:
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Abstract ( 445 )
The distribution of stratigraphic intercalations is a major controlling factor that accounts for heterogeneity in many thick, oil-prone sedimentary layers. Using as an example the Triassic reservoir of the A I member of Akekule Formation in Block 9 of the Tahe Oilfield, which comprises a thick layer of delta distributary channel sand bodies, and combined with core and well log data, the stratal intercalations can be quantitatively classified into two types of clay and carbonate. On this basis, quantitative criteria for the classification of the two types of intercalations are established. Based on the sedimentary environment of the study area, horizontal well data and correlation of interbedded strata in the local dense drilling zone, the pattern and extent of the intercalations are determined. Marked point process simulation is the preferred method to determine the distribution of intercalations during random simulation, and subsequently the random simulation results are modified by data spread. Consequently the three-dimensional certainty geological model of the intercalations is established by human-computer interaction. Intercalations research results provide a geological basis for petroleum reservoir development planning and management.

Research on Seismic and Sedimentary Facies in the Sha-3 Member of the Xingma Area

Science & Technology Review. 2010, 28 (19): 26-29. ;  doi:
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Abstract ( 398 )
Gravity flow deposits of the Sha-3 Member in the Xingma area are characterized by strong heterogeneity and rapid lateral facies changes. As a result, it is very difficult to undertake reservoir prediction. In order to solve these problems, sequence stratigraphic analysis and seismic waveform classification techniques for seismic facies are employed in this study. Based on characteristics of sedimentary and seismic reflection, the relationship between reservoir characteristics and seismic waveforms is studied and a reasonable spatial distribution of multiple stages of reservoir sandstones is well predicted. These results show that the entire Sha-3 Member in the study area can be divided into three sequences, and each sequence constitutes one fining-upward sedimentary cycle. The gravity flow deposits show characteristics of quasi-continuous reflection, moderate amplitude and mid-low frequency in seismic sections. In plan view, results can be divided into 10 seismic facies and three seismic facies domains that correspond to middle fan braided channel facies, middle fan-front facies and outer fan-lacustrine facies. By comparison, sequence SQ3 and the southern part of sequence SQ2 are evaluated as the most favorable exploration targets.

Study on Fault Sealing of the Maxi Fault in the Raoyang Depression

Science & Technology Review. 2010, 28 (19): 30-35. ;  doi:
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Abstract ( 424 )
Faults can become pathways for migration of hydrocarbons, but they also can be barriers to reservoirs in different geologic epochs. Hence, it is important to study fault sealing performance to determine the distribution of reservoirs. Several factors can influence fault sealing performance, namely, the lithologic associations on two sides of a given fault, mudstone-smearing, the relationship between fault-movement periods and hydrocarbon migration intervals, and the stress of fracture surfaces. This study examined these factors for the fault sealing performance of the Maxi fault in the Raoyang depression. Fault sealing performance was evaluated using the synthesized evaluation method. Results show that the Maxi Fault grew actively in the Middle-late Cenozoic. Fault sealing was poor in this period, while hydrocarbon migration was at a peak during this interval. Thus, it appears the fault became a pathway for hydrocarbon migration. After that, the Maxi fault stopped growing for a long time. At the same time, fault sealing became more dominant, showed the specialties as upper-better and lower-worse. This situation was beneficial in creating a petroleum reservoir in Shahejie strata. However, petroleum could not be trapped in the foot wall of the Maxi Fault.

Dynamic Reserve Calculation of a Low Alumina-Silica Ratio Thin Orebody via Visual Simulation

Science & Technology Review. 2010, 28 (19): 36-41. ;  doi:
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Abstract ( 469 )
The advanced Dimine digital mine software system was used to set up a bauxite mining database of the Huihe mining district in Chongqing. A statistical analysis of a number of original samples and a variation functional analysis of spatial data were made for use with a selection principle based estimation method. The distance-power-inverse-ratio method and traditional methods were adopted for grade estimation of useful chemical components in an orebody. Then, the estimated block modes were displayed separately according to respective grade level of A/S, Al2O3, and reserve statistics were completed using the sublevel data. In addition, the authors conducted a comparative analysis for reserve calculations results based on the different estimation methods, and developed an accuracy test. The study found that there is a correlation among the samples of the mining district, and the content is not completely random, but the directional variability is not apparent from the three-direction study. Useful mineral compositions occur in layered, stratiform-like, and plane configurations manifest as regional enrichment, and the boundaries between different grades are very clear. The average grade of A/S and Al2O3 exhibits a steady rising trend as the sublevel height increases. Meanwhile, the peak value of the reserve appears in the middle of Huihe mining district, near 900m. However, there are different degrees of reserves predicted using various estimation methods and statistical analysis of data, which was obtained from preliminary designs. This investigation indicates traditional methods (the block method, in particular) more suitable for grade estimation and reserve calculation of orebodies in this mining district (thin orebody). Its results provide a theoretical basis for carrying out stock assessments, making reasonable mining designs, and production plan.

Method of RBF Network Parameters for the Optimization of Switched Reluctance Motor Modeling

Science & Technology Review. 2010, 28 (19): 42-45. ;  doi:
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Abstract ( 1066 )
Based on the evolutionary algorithm, Quantum-behaved Particle Swarm Optimization (QPSO), and the local search strategy, Structured Nonlinear Parameter Optimization Method (SNPOM), a hybrid parameter optimization algorithm (QPSO-SNPOM) for RBF neural networks is proposed. The approach starts with a population of random initial parameter values, and updates the population by selection, crossover, and replacement according to the fitness values obtained by the SNPOM. It is shown through simulation tests that the combination provides better results than either method alone(QPSO or SNPOM) and many other existing algorithms. The switched reluctance motor is a new development in motor technologies, and its characteristics, such as the small starting current, the strong starting torque, and simple structure, have made it a very attractive design. However, it has proven difficult to develop accurate SRM models because SRM exhibits highly-nonlinear characteristics. Therefore, we construct a RBF network model of the SRM, and apply our new method, QPSO-SNPOM, to optimize the parameters of the RBF network model. The simulation results show that the RBF training error is smaller, and the system is more capable of generalization when optimized by this new method rather than by SNPOM. In addition, the training time is shorter than it is when applying evolutionary algorithms. We also confirm that the trained RBF network completely models the characteristics of the SRM.

Spatial Positioning System Based on the Sound Sensor Array

Science & Technology Review. 2010, 28 (19): 46-49. ;  doi:
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Abstract ( 484 )
The source location technology has an important application in areas such as video conference, voice recognition, target location and hearing devices. Sound sensor array is composed by certain sound sensors. Compared with a single sound sensor, it can improve SNR. It has strong space selective and is available to sound signal without moving. At the same time, it can realize the self-adaptive detection, localization and tracking of sound source in a certain range, which makes it have wide application in many areas. How to blend the audio data from each node to achieve the accurate positioning and tracking is a hot study at present. This paper uses TI's MSP430F149 MCU as the control core of the sound sensor array spatial positioning system, selects a buzzer as the sound source. Different receiving points which on the space coordinate system collects sound signals to amplify and filter. According to the processed signal, MCU applies the positioning theory based on delay to form space coordinate localization algorithm and locate the sound source. The realization method is simple and test results indicate the position of high precision.

Bifurcation Control for Delayed Hopfield Neural Networks

Science & Technology Review. 2010, 28 (19): 50-54. ;  doi:
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Abstract ( 420 )
In recent years, bifurcation control has attracted many researchers from various disciplines. The aim of bifurcation control is to design a controller to modify the bifurcation properties of a given nonlinear system, and achieve desirable dynamical behaviors. The bifurcation control of a class of Hopfield neural network with three delays is investigated. In contrast to the general time-delayed state feedback control, based on the Hopf bifurcation theory and the choice of time delay as the bifurcation parameter, a new hybrid control strategy is proposed, in which the time-delayed state feedback and parameter perturbation are used to control the Hopf bifurcation of the model, and some new conclusions are obtained. In addition, we examine the effects of coefficient perturbation. Furthermore, known results are used to check the conclusions, and the new conclusions are shown to be helpful in changing and delaying the evolution of bifurcation, which has applications in a variety of areas such as controlling period bifurcation and chaos. Finally, we use examples and numerical-simulation results to confirm that the hybrid controller using time delay is an efficient means to control Hopf bifurcation.

Complex Dynamics of a Parametrically Excited System with Delayed Position Feedbacks

Science & Technology Review. 2010, 28 (19): 55-58. ;  doi:
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Abstract ( 435 )
A single-degree-of-freedom system with quadratic, cubic, and parametrically excited terms is considered. We introduce an active control, i.e. a linear delayed-position feedback control, to the system, and the effects of the delayed feedback on the dynamics of the system are studied qualitatively. First, the normal form method is proposed to investigate the dynamics of the system with varying delay. Then the second-order approximation of the periodic solution is obtained, and is used to predict the stability of the bifurcation branches and the variation of the number of solutions with varying time delay. It is found that time delay can make the trivial equilibrium lose its stability, and induce the multiple attractors coexisting in the system. Finally, the numerical results are obtained through the 4th-order Runge-Kutta and point-to-point mapping methods. The basins of attraction are classified. In addition, the quasi-periodic attractor time delay induces is also obtained. The agreement of the numerical and theoretical results verifies the validity of the theoretical predictions. It is found that varying the delay can induce the complex dynamical behaviors in the system. This paper provides potential applications of these findings for the study of stabilization of controlled systems and chaotic motions.

Estimation of Solution Matrix of Perturbed Continuous Riccati Matrix Equation

Science & Technology Review. 2010, 28 (19): 59-61. ;  doi:
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Abstract ( 387 )
The Riccati matrix equation has a theoretical and practical importance in the control theory and the state estimation problems. The estimation of the solution matrix of the perturbed continuous Riccati matrix equation is studied in this paper. The perturbation parameters of this equation are of norm-bounded uncertainty. The new upper and lower bounds of the solution matrix for the perturbed continuous Riccati matrix equation are derived by constructing two semi-definite matrices, using matrix inequalities and characteristics of eigenvalues of the matrices. The calculations of upper and lower bounds require only the eigenvalues of the matrices and the solution of linear matrix inequalities. All estimations of bounds are given by matrix inequalities. Thus one does not have to solve the higher-order equation. The results obtained are verified by a numerical example, and the feasibility is illustrated.

Protamine-Modified Iron Oxide Magnetic Nanoparticles are Efficient Gene Vectors for Magnetofection

Science & Technology Review. 2010, 28 (19): 62-67. ;  doi:
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Abstract ( 536 )
Functionalized magnetic iron oxide nanoparticles (MNPs) can play crucial roles in medical applications, including cancer magnetic fluid hyperthermia, magnetic resonance imaging, anticancer drug delivery, and magnetofection. Here, the use of modified MNPs coated with protamine peptides containing nuclear localization signal sequences as gene carriers (PRO-MNPs) for magnetofection of HepG2 cells was tested. Fe3O4 nanoparticles were synthesized by chemical co-precipitation, modified by 3-aminopropyltriethoxysilane, and were covalently attached to protamine. The size, zeta potential, and coating characteristics of MNPs were analyzed by transmission electron microscopy, Zetaplus zeta potential measurement, and Fourier transform infrared imaging, respectively. The magnetofection efficiency of PRO-MNPs was observed by a laser scanning confocal microscope using pEGFP-N1 as the reporter gene. The mean size of the magnetic nanoparticles was about 10nm. The expression level of green fluorescence protein in HepG2 cells transfected with PRO-MNPs was significantly higher than that of cells transfected using vigofectin reagent. The results indicate that PRO-MNPs offer a novel non-viral gene transfection vector, particularly for cancer gene therapy when combined with magnetic-induced hyperthermia.

Preparation and Characterization of Polyethyleneimine Modified Fe3O4 Magnetic Nanoparticles

Science & Technology Review. 2010, 28 (19): 68-72. ;  doi:
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Abstract ( 454 )
The orthogonality test was used to obtain the optimal technology for preparing magnetic nanoparticles coated with covalently-bound biofunctional polyethyleneimine (PEI). We propose PEI-Fe3O4 magnetic nanoparticles as a mediator for hyperthermia in vitro and in vivo. The processing of polyethyleneimine modified Fe3O4 magnetic nanoparticles includes the preparation of magnetic Fe3O4 nanoparticles and then integrating the Polyethyleneimine modified magnetic nanoparticles and Fe3O4. Examination and characterization of the polyethyleneimine modified Fe3O4 magnetic nanoparticles were performed using simple methods. Simple analyses of the factors affecting the preparation of polyethyleneimine modified Fe3O4 magnetic nanoparticles were made, and the optimal technology was obtained after the optimization of these factors by means of a L8(27) orthogonality test. The optimal technological conditions obtained were: use of ammonium chloride to keep the pH in the range of 9.3~9.7; the ferric ions must be kept in the ratio Fe2+/Fe3+=1:1.75; a polyethyleneimine solution with mass-fractional of 20% should be used; a mechanical stirring at of 1400r/min should be maintained; and the reaction temperature should be held at 85℃. The resulting polyethyleneimine modified Fe3O4 magnetic nanoparticles were characterized using Fourier transform infrared spectroscopy, transmission electron microscope, X-ray diffraction, vibrating sample Magnetometry, and Thermogravimetric Analysis. The results show that the particles have a spinel structure, are superparamagnetic, and have good performance Their diameter is about 9.4nm, their magnetic concentration is 82%, and their magnetization is 61.962emu/g. Further investigation is needed to confirm the nanoparticles effectiveness as a mediator for hyperthermia in vitro and in vivo.

Preparation of Carboxyl Magnetic Fluid and Surface Modification by Bovine Serum Albumin

Science & Technology Review. 2010, 28 (19): 73-76. ;  doi:
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Abstract ( 457 )
Magnetic nanoparticles are now used in magnetic-mediated hyperthermia for tumor treatment. Magnetic Fe3O4 nanoparticles with a mean diameter of 10~15nm, in the range of superparamagnetism, are normally prepared by the traditional method of co-precipitation from ferrous and ferric electrolyte solutions. This work presents a novel and efficient way to prepare a stable aqueous nanomagnetite dispersion. A stable ferrofluid containing Fe3O4 nanoparticles coated by carboxyl groups was synthesized via improved co-precipitation in the presence of polyacrylic acid. Furthermore, Bovine Serum Albumin (BSA) used as the model targeting molecule was conjugated with magnetic nanoparticles via activation by N-ethyl-N'-(3-dimethylamino-propyl) carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide(NHS). The results indicate that the average diameter of PAA oligomers coated Fe3O4 particles was about 10nm, and had a good dispersion in aqueous phase. In addition, both quantitative analysis and fluorescent microscopy observation confirmed that BSA can be stably conjugated with carboxyl-Fe3O4 particles via EDC and NHS activation.

Effects of Thermal Seed Magnetic Induction Heating in Muscle Phantoms

Science & Technology Review. 2010, 28 (19): 77-80. ;  doi:
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Abstract ( 443 )
We explored the effects of different amounts and different arrangements of thermal seeds with magnetic induction heating in an experimental muscle model (agar phantom). The agar phantoms were generated using thermal seed implant templates with the following features: single stars; 2 stars; 3×3 array of exclusive fabrics; 4×4 array row cloth; double layers 4×4 different spacing row cloth. A thermocouple was implanted to measure the temperature of the agar phantom. The agar phantom was then placed on poles to provide a magnetic field to heat the thermal seeds. In models containing one or two thermal seeds, the temperature reached 25~32℃ upon heating. This heating function of the thermal seeds was also stable. In another model containing nine thermal seeds, the temperature reached 37.5℃ between two thermal seeds, while the temperature 1.0cm away from the thermal seed array was 30.1℃. In a model containing 16 thermal seeds, the center of the thermal seed array center reached 52.9℃ after applying the magnetic field. In tests of different spatial distances of the thermal seed in the magnetic field, the temperature at the center reached ≥65℃, and progressively decreased with increasing distance from the focal point, dropping to 42~45℃ at 1.0cm away from the thermal seed array. Comparing models with a layer spacing of 1.0cm and 0.8cm, the difference in temperature was approximately, 1.0℃. In comparisons of tests with layer spacing of 1.0cm and 0.5cm spacing, the temperature difference between the measured points was about 3.0℃. Here, we have shown that, in an experimental model of muscle(agar phantom), magnetic induction of thermal seeds within a specific target area can provide a temperature suitable for cancer thermal ablation.

Effects of a 115-kHz Intermediate Frequency Alternating Magnetic Field on the Reproductive System of Male Mice

Science & Technology Review. 2010, 28 (19): 81-85. ;  doi:
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Abstract ( 448 )
Objective To assess the potential effect of intermediate frequency (IF) alternating magnetic field on reproductive system of experimental mice. Methods Male Balb/C mice (18-26 g) were randomly divided into four groups (n=8). Mice receiving radiation were exposed to the magnetic field (115 kHz, 10.5kA/m) for 1 hour per day for 7days (short-term exposure group) or 28 days (long-term exposure group). Each radiation group had a sham control counterpart. After treatment mice were sacrificed and testis, epididymal sperm were separated. Testicular weight, sperm density, sperm activity rate, and sperm motility were examined. Histopathological analysis of the testis was performed. Results The IF did not affect sperm activity of experimental mice. The testicular weights of short-term group were increased. The sperm density and sperm motility of long-term exposure group were increased. Conclusion There was no evidence of toxicity associated with exposure to the magnetic field of examined parameters. IF might promote testis cells proliferation.

Experimental Evaluation of Systemic Toxicity and Safety of Exposure to Intermediate Frequency Alternating Magnetic Radiation

Science & Technology Review. 2010, 28 (19): 86-92. ;  doi:
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Abstract ( 427 )
We performed an experimental study to determine the safety and systemic toxicity of a 100-kHz intermediate frequency alternating magnetic field. Adult male beagle dogs were randomly divided into a control group and two experimental groups, which receive either continuous exposure group or twice-weekly exposure to the magnetic field. Both experimental groups were exposed to the magnetic field for 4 weeks. Blood, urine, immune function, bone marrow smears, sperm quality, and morphology were assessed before and after irradiation. After the 4-week exposure, the dogs were sacrificed and the major organs were collected for pathological observation. Comprehensive analyses of these parameters showed that, except for a few indicators, there were no significant differences between the two experimental groups and the control group. The differences in the conventional indicators were within the normal range. Thus, exposure to an intermediate frequency magnetic field had no significant biological effects in beagle dogs, and there was no correlation between irradiation time or magnetic field with the biological effects. These results provide evidence that intermediate frequency magnetic fields are safe and suitable for use in clinical trials.

Active Targeting Magnetic Iron Oxide Nanoparticles: Current Status and Novel Applications in Tumor Hyperthermia

Science & Technology Review. 2010, 28 (19): 108-112. ;  doi:
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Abstract ( 433 )
Magnetic nanoparticles are important tools in tumor imaging and therapy. However, low therapeutic concentration of the nanoparticles at the tumor sites has limited their clinical applications. Active targeting employs magnetic nanoparticles conjugated to specific ligands that selectively bind to biomarkers on target cells. Several receptor systems are overexpressed in cancerous diseases and have been investigated as targets for ligand-directed magnetic nanoparticles. The target receptors undergo repeated recycling between the cell surface and internalization, and bind to magnetic nanoparticles, thereby amplifying the magnetic signal for more precise diagnosis and treatment. This paper summarizes the recent advances in the development of active targeted magnetic iron oxide nanoparticles for tumor imaging and therapy. Magnetic nanoparticles with an alternating magnetic field can convert electromagnetic energy into heat and confine the heat to the tumor tissue. Magnetic fluid hyperthermia is a promising approach to cancer therapy because it not only directly kills cancer cells, but also indirectly activates anticancer immunity. Modifying the surface of magnetic nanoparticles to target specific molecules could improve their intracellular accumulation and their ability to target on tumor cells, and thus enhance their hyperthermia effects.

Progress in Preventing and Curing Restenosis by Magnetic Induction Hyperthermia

Science & Technology Review. 2010, 28 (19): 113-117. ;  doi:
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Abstract ( 425 )
Coronary heart disease is a type of heart disease that poses serious risk to human health, and its incidence is greatly increasing in China. Percutaneous transluminal coronary angioplasty (PTCA) is widely used to treat patients with coronary artery disease. However, restenosis after PTCA, which occurs in 30%~50% of cases, is a severe problem that limits the efficacy of the intervention. Restenosis is a complex process caused by many factors, including elastic recoil of vessels, thrombosis, neointima formation, blood vessel wall remodeling, and inflammatory reactions. One of the most important steps in restenosis is the excessive proliferation of smooth muscle cells. Magnetic induction hyperthermia treatment offers a new approach to prevent and treat restenosis, by inhibiting the proliferation of vascular smooth muscle cells. Magnetic induction hyperthermia avoids the need for surgery, does not carry risk of adverse physical stimulation, and can reduce the suffering of patients. In this paper, we review the effects of magnetic induction hyperthermia on vascular smooth muscle cells and endothelial cells, and the clinical potential for this approach.
Focus

Science & Technology Review. 2010, 28 (19): 120-121. ;  doi:
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Abstract ( 330 )
主编心语

Science & Technology Review. 2010, 28 (19): 127-127. ;  doi:
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Abstract ( 304 )
走向职场

Science & Technology Review. 2010, 28 (19): 129-129. ;  doi:
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Abstract ( 334 )

Science & Technology Review. 2010, 28 (19): 130-134. ;  doi:
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Abstract ( 288 )

Science & Technology Review. 2010, 28 (19): 135-139. ;  doi:
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Abstract ( 294 )

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