Pulsed Electromagnetic Field (PEMF) Treatment Reduces Lipopolysaccharide-Induced Septic Shock in Mice

Despite advances in medicine, mortality due to sepsis has not decreased. Pulsed electromagnetic field (PEMF) therapy is emerging as an alternative treatment in many inflammation-related diseases. However, there are few studies on the application of PEMF therapy to sepsis. In the current study, we examined the effect of PEMF therapy on a mouse model of lipopolysaccharide (LPS)-induced septic shock. Mice injected with LPS and treated with PEMF showed higher survival rates compared with the LPS group. The increased survival was correlated with decreased levels of pro-inflammatory cytokine mRNA expression and lower serum nitric oxide levels and nitric oxide synthase 2 mRNA expression in the liver compared with the LPS group. In the PEMF + LPS group, there was less organ damage in the liver, lungs, spleen, and kidneys compared to the LPS group. To identify potential gene targets of PEMF treatment, microarray analysis was performed, and the results showed that 136 genes were up-regulated, and 267 genes were down-regulated in the PEMF + LPS group compared to the LPS group. These results suggest that PEMF treatment can dramatically decrease septic shock through the reduction of pro-inflammatory cytokine gene expression. In a clinical setting, PEMF may provide a beneficial effect for patients with bacteria-induced sepsis and reduce septic shock-induced mortality.     

Electrical Conductivity of Metal Powders under Shock Compression

The electrical conductivity of a series of metal powders under shock compression is measured by an electrocontact technique. Initially, the metal particles are covered by an oxide film, and the powder is non-conducting. Under shock compression, the powder acquires macroscopic conductivity. The electrical conductivity of the shock-compressed powder depends substantially on the metal, porosity, particle size, and shock-wave pressure. The macroscopic electrical conductivity behind the shock-wave front is uniform within the experimental error. The dependences for fine and coarse aluminum powders on the shock-wave pressure are found. It is demonstrated that these dependences are nonmonotonic. For high shock-wave pressures, the electrical conductivity of the substance decreases. This behavior is assumed to be related to strong temperature heating of the substance under shock compression. Estimates of temperature show that shock compression can induce melting and partial vaporization of the metal. The same is evidenced by the behavior of electrical conductivity whose value for fine particles is close to the electrical conductivity of the melt. The electrical conductivity of the coarse powder is heterogeneous because of the strong thermal nonequilibrium of the particle during shock compression. An analysis of results for different metals shows that the basic parameter responsible for electrical conductivity of the shock-compressed powder is the dimensionless density. __________ Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 5, pp. 128–139, September–October, 2005.     

非均匀磁场电磁流量计磁场的计算与分析

在非均匀磁场电磁流量计原理的基础上,利用matlab解出了励磁线圈的截面形状,并通过ANSYS对励磁线圈的磁场进行仿真,结果表明所求解的励磁线圈所产生的磁场符合非均匀电磁流量计的要求。     

交变电磁场对PFS溶解液电导率的影响研究

电磁场变化具有改变PFS(聚合硫酸铁)溶解液电导率的特性.通过交变电磁实验证明:常温条件下,聚合硫酸铁溶解液的电导率在电压为0～220 V、电流为0～1.2A、频率为0～400 Hz、磁化时间为0～180 s范围内均呈现“V”字形变化,其最佳参数为电压100 V、电流0.7A、频率150 Hz、磁化时间60s;由正交试验分析可得,4个因素影响PFS溶解液电导率的主次顺序为:磁化时间＞频率＞电压＞电流.经交变电磁场磁化处理的PFS溶解液的电导率值比常规电导率值提高了14％,稳定性提高了1倍.     

Electromagnetic Field and Current Waves in a Conductor Compressed by a Shock Wave in a Magnetic Field

A physically correct and mathematically rigorous solution of the problem on the structure of an electromagnetic field formed when a shock wave enters a conducting half–space in a transverse magnetic field is obtained. It is shown that only physically grounded boundary conditions lead to a noncontrovercial pattern of the electromagnetic field and a system of currents in a conductor. The main parameters and characteristic times are found, which determine the structure of current waves in a metal. The solution in the uncompressed region is determined by the parameter R₁ = µ₀₁D²t and that in the compressed region by the parameter R₂ = µ₀₂(D—U)²t (₁ and ₂ are the electric conductivities of the uncompressed and compressed substance, respectively, µ₀ is the magnetic permeability of vacuum, D is the wave–front velocity, U is the mass velocity, and t is the time). The parameter for the compressed substance R ₂ coincides with the parameter obtained previously for the shock–wave dielectric—metal transition; the governing parameter for the uncompressed substance R ₁ is obtained for the first time. The asymptotic solutions of the problem for small and large times and the special case R ₁ = R ₂ considered help in understanding the physical meaning of the solution found.     

高频三角波电磁场防治水系统中微生物污垢的研究

工业水系统中微生物污垢广泛存在，实验采用高频三角波对模拟工业水系统中的微生物污垢的防治进行了研究。主要考察了不同流速的流体在未处理和经过不同频率高频三角波处理后，不同材料表面上微生物污垢的生长量的差别以及微生物污垢的生长厚度和形态方面的差异。结果表明：一定流速下5000Hz高频三角波电磁场对实验中使用的非金属材料有明显抑制其表面微生物污垢生长的作用，但是对实验中的金属材料没有抑制作用；高频三角波的抑制作用在距离加载位置较近的实验段比在距离较远的实验段的作用突出，随着与加载位置距离的增大，抑制作用逐渐减弱。     

平行磁场作用下电沉积Co-Ni-Mn-P磁性薄膜

在平行磁场作用下电沉积Co-Ni-Mn-P磁性薄膜。研究了平行磁场对电沉积过程及薄膜性能的影响。研究发现:施加平行磁场,有利于提高离子的传质速率,从而提高沉积效率。平行磁场作用下电沉积制备的Co-Ni-Mn-P磁性薄膜呈现出"枝晶状"结构,矫顽力和比饱和磁化强度更高。     

Chemical Preparation and Shock Wave Compression of Carbon Nitride Precursors

Two synthetic routes have been developed to produce high-molecular-weight organic precursors containing a high weight fraction of nitrogen. One of the precursors is a pyrolysis residue of melamine-formaldehyde resin. The second precursor is the byproduct of an unusual low-temperature combustion reaction of tetrazole and its sodium salt. These precursors have been shock compressed under typical conditions for diamond and wurtzite boron nitride synthesis in an attempt to recover a new ultrahard carbon nitride. The recovered material has been analyzed by X-ray diffraction, FTIR, and Raman microprobe analysis. Diamond is present in the recovered material. This diamond is extraordinarily well ordered relative to diamond shock synthesized from carbonaceous starting materials.     

Tailoring Nylon 6/Acrylonitrile-Butadiene-Styrene Nanocomposites for Application against Electromagnetic Interference: Evaluation of the Mechanical,Thermal and Electrical Behavior,and the Electromagnetic Shielding Efficiency

Nylon 6/acrylonitrile-butadiene-styrene nanocomposites were prepared by mixing in a molten state and injection molded for application in electromagnetic interference shielding and antistatic packaging. Multi-wall carbon nanotubes (MWCNT) and maleic anhydride-grafted ABS compatibilizer were incorporated to improve the electrical conductivity and mechanical performance. The nanocomposites were characterized by oscillatory rheology, Izod impact strength, tensile strength, thermogravimetry, current-voltage measurements, shielding against electromagnetic interference, and scanning electron microscopy. The rheological behavior evidenced a severe increase in complex viscosity and storage modulus, which suggests an electrical percolation phenomenon. Adding 1 to 5 phr MWCNT into the nanocomposites produced electrical conductivities between 1.22 × 10⁻⁶ S/cm and 6.61 × 10⁻⁵ S/cm. The results make them suitable for antistatic purposes. The nanocomposite with 5 phr MWCNT showed the highest electromagnetic shielding efficiency, with a peak of –10.5 dB at 9 GHz and a value around –8.2 dB between 11 and 12 GHz. This was possibly due to the higher electrical conductivity of the 5 phr MWCNT composition. In addition, the developed nanocomposites, regardless of MWCNT content, showed tenacious behavior at room temperature. The results reveal the possibility for tailoring the properties of insulating materials for application in electrical and electromagnetic shielding. Additionally, the good mechanical and thermal properties further widen the application range.     

Synergistic Effect of PVDF-Coated PCL-TCP Scaffolds and Pulsed Electromagnetic Field on Osteogenesis

Bone exhibits piezoelectric properties. Thus, electrical stimulations such as pulsed electromagnetic fields (PEMFs) and stimuli-responsive piezoelectric properties of scaffolds have been investigated separately to evaluate their efficacy in supporting osteogenesis. However, current understanding of cells responding under the combined influence of PEMF and piezoelectric properties in scaffolds is still lacking. Therefore, in this study, we fabricated piezoelectric scaffolds by functionalization of polycaprolactone-tricalcium phosphate (PCL-TCP) films with a polyvinylidene fluoride (PVDF) coating that is self-polarized by a modified breath-figure technique. The osteoinductive properties of these PVDF-coated PCL-TCP films on MC3T3-E1 cells were studied under the stimulation of PEMF. Piezoelectric and ferroelectric characterization demonstrated that scaffolds with piezoelectric coefficient d₃₃ = −1.2 pC/N were obtained at a powder dissolution temperature of 100 °C and coating relative humidity (RH) of 56%. DNA quantification showed that cell proliferation was significantly enhanced by PEMF as low as 0.6 mT and 50 Hz. Hydroxyapatite staining showed that cell mineralization was significantly enhanced by incorporation of PVDF coating. Gene expression study showed that the combination of PEMF and PVDF coating promoted late osteogenic gene expression marker most significantly. Collectively, our results suggest that the synergistic effects of PEMF and piezoelectric scaffolds on osteogenesis provide a promising alternative strategy for electrically augmented osteoinduction. The piezoelectric response of PVDF by PEMF, which could provide mechanical strain, is particularly interesting as it could deliver local mechanical stimulation to osteogenic cells using PEMF.     

Iron Removal during Recovery of Silicon from Sawing Waste by Applying Magnetic Field

The removal of metal impurities is essential when recycling silicon sawing waste. In this study, Si, SiC, and metal fragments were separated by sedimentation in an applied electrical field. A magnetic field was incorporated into the system to promote the separation of iron-based fragments from the sawing waste. When a 1 V/cm electrical field and a 0.3 T magnetic field were applied for 24 h to the system in a pH7 solution, the residual amount of iron reduced to less than 0.0185% of the initial amount. The maximum SiC content in the recovered powder was 87.8 wt%, while the minimum was 12.3 wt%, i.e., roughly 87.7 wt% Si. Applying a magnetic field to the recycling system can effectively reduce the residual iron content; in addition, Si, SiC, and metal fragments can be separated in a single procedure.     

导电炭黑/三元乙丙橡胶电磁屏蔽复合材料的性能研究

以三元乙丙橡胶(EPDM)为基体、导电炭黑为导电填料,并添加增塑剂,制备可挤出加工的炭黑/EPDM电磁屏蔽复合材料,研究炭黑和增塑剂的品种和用量对复合材料性能的影响.结果表明:添加结构度高、粒径小的导电炭黑有利于形成导电网络;随着炭黑用量的增大,复合材料的体积电阻率逐渐降低,当炭黑用量达到18份时,可以得到体积电阻率小于10Ω·cm的导电橡胶复合材料;添加20份石蜡油时,能有效降低胶料的门尼粘度.     

磁场处理对水-乙酸体系汽液平衡的影响

在不同磁感应强度的磁场中 ,以不同的磁化处理方式和不同的磁化时间 ,研究了磁场处理对水 -乙酸体系汽液平衡的影响。研究结果表明 ,磁场对该体系的汽液平衡有一定的影响 ,磁化效果总体上呈正效应 ,但磁化效果与磁感应强度不成比例 ,有一个最佳值。在不同的磁化处理方式中 ,溶液达到充分磁化的时间不同 ,搅拌磁化效果优于静置磁化。磁化效果随溶液的组成而变 ,在乙酸摩尔组成为 0 .5 5～ 0 .75时效果显著     

用电磁粒子速度计实验研究一种TATB基钝感炸药的冲击响应

针对一种新的TATB基钝感炸药(Tx),应用组合式电磁粒子速度计(EMV)测试技术,测量了炸药直接加载、增加有机玻璃隔板以及炸药驱动飞片3种加载状态下炸药内部的粒子速度历程和冲击波轨迹。根据测试结果,分析了不同加载压力下炸药的冲击响应过程。结果表明,炸药直接加载时,加载压力最高,Tx钝感炸药很快达到爆轰状态,到爆轰距离约为1.5mm;在增加有机玻璃隔板、加载压力为14.2GPa时,与直接加载时炸药粒子速度一致,Tx钝感炸药的到爆轰距离明显增加,约为5mm;在炸药驱动飞片、加载压力为9.5GPa时,Tx钝感炸药的粒子速度逐渐降低,存在一定钝化现象,到爆轰距离达到20mm以上。     

Observation of Compression and Failure Waves in PMMA by Means of Synchrotron Radiation

The possibility of using synchrotron radiation for density measurements in shockcompressed polymethylmethacrylate destroyed in a failure wave is demonstrated for the first time. Parameters of the compression and failure processes are presented.     

电磁场对形成MgO-C质耐火材料MgO致密层的影响

采用碳含量为6%（质量分数）的MgO–C质耐火材料和CaO与SiO2质量比为0.87的钢渣,分别在中频感应炉和电阻炉中氩气气氛下进行抗渣侵蚀实验,利用X射线衍射仪、扫描电子显微镜和能谱仪对抗渣样品渣线界面层进行分析。结果表明：在电磁场环境中,MgO–C质耐火材料界面层没有发生Mg（g）氧化反应,因此未形成MgO致密层;...     

内置电磁线圈注塑模具中取向磁场三维有限元模拟

使用三维有限元软件Opera 3d对在内置电磁线圈的注塑模具中的磁场强度(H)及分布进行了模拟。结果表明,在电流强度(I)低于5.00 A时,模腔中的H随电磁线圈中I值的增加而线性增加,I高于5.00A后,由于模具材料被饱和磁化,H的模拟值偏离实测值。通过模拟还发现,模腔中H及均匀性随导磁模具钢与非导磁模具钢磁导率(μ_r)比值的增大提高。     

永磁场对气体中分子传质过程的影响

在不同磁感应强度的磁场中,研究了磁场对气体中分子传质过程的影响。研究结果表明,磁场对水、甲醇、乙醇、甲酸及乙酸在空气中的分子传质过程具有正效应,即在磁场中的扩散系数增大。定量计算表明,其扩散系数提高4%～7%。磁场对苯、甲苯、丙酮及甲基乙基酮在空气中的分子传质过程基本无影响。对磁场影响气体中分子传质过程的机理进行了探讨。     

导电炭黑/杜仲胶复合材料电磁屏蔽性能的研究

采用机械共混法制备了导电炭黑/杜仲胶复合材料,研究炭黑用量对复合材料电性能和电磁屏蔽性能的影响。结果表明：随着炭黑用量的增加,复合材料的导电率增大,当炭黑用量为25份时,导电率达到3.3S/cm,导电率遵循导电逾渗规律;复合材料的Payne效应越来越大,有利于形成稳定的导电网络;复合材料的拉伸强度逐渐增大后略微降低,断裂伸长率先增加后逐渐下降。复合材料的屏蔽效能增大,当炭黑用量为20份时,屏蔽效能最高能达到33.2dB,可以满足一般工业或者商业用电子设备的要求。     

基于介稳区的电磁抑垢最佳磁场强度探寻

电磁抑垢技术以其投资少、无污染等优点备受业内人士瞩目。合理选择电磁参数,是达到电磁抑垢最佳效果的必要条件之一。根据电导率滴定法,设计了动态电磁实验装置,在给定实验条件下进行了实验,并对电导率随时间变化的特征进行了对比分析,得到不同溶液浓度和不同电磁场强度作用下的碳酸钙结晶介稳曲线,从介稳区的角度分析电磁场对碳酸钙结晶成核诱导期的影响,确定了电磁场抑制碳酸钙结晶的最佳磁场强度值为200Gs。