RF对纳米金标记的RNase-S局部加热效应的研究

目的 在纳米级或微米级结构的线度可以和热辐射波长λ相比拟的状态下的辐射热传导的研究具有重要的实用意义，通过建立生物模型来研究射频电磁辐射(RF)对纳米结构辐射热传导的特征，并探讨微波非热效应的可能作用机制。方法 将制备的纳米金标记的RNase-S样品通过常规的Poly-C水解能力的测定及哪谱的测定分析，确定酶的2级结构的重组成功和活性的存在后，比较RF对样品、水和空气的热效应。结果 通过紫外分光光度计对制备的纳米金标记的RNase-S样品的Poly-C水解能力的测定及谱的测定，表明研究中使用的生物模型和RNase A模拟得十分满意。空气浴中的封装空气样品的散热曲线呈现指数衰减规律，而空气样品的加热过程呈指数增加趋势。空气浴中的双蒸馏水样品的加热过程基本上是线性增加。但是，水浴的纳米金标记的RNase-S样品的加热过程却基本上保持恒定值。结论 RF辐射在实验的条件下会由于被加热介质的不同热物理性质表现为不同的加热效果，对于含有纳米金属的微结构，可能会在局部产生微涡流发热。以纳米颗粒为热源的辐射热传导可能会和生物大分子的结构调整发生谐振从而不表现出样品整体宏观的升温。生物功能性大分子关键部位局部加热的谐振吸收是微波等物理因素的非热生物效应的可能作用机制。     

睾丸局部热作用对幼鼠生精细胞凋亡的影响

目的探讨睾丸局部热作用对幼鼠生精细胞凋亡的影响。方法48只健康幼年期SD雄性大鼠随机分为热处理组(43℃,15min)和对照组(22℃,15min):分别按睾丸局部处理后2h,6h,24h,14d分成4个亚组。应用电镜和原位末端标记法(TUNEL)检测各亚组幼鼠睾丸生精细胞凋亡情况,并在光镜下观察睾丸组织学变化。结果电镜显示热处理组除2h外各组均出现生精细胞凋亡表现;TUNEL法检测结果用生精细胞凋亡指数(AI)表示;热处理组2hAI与对照组相比无统计学意义,热处理组6hAI高于对照组(P<0.05),热处理组24h和14dAI明显高于对照组(P<0.01)。结论睾丸局部热作用导致幼鼠生精细胞凋亡增加。     

Transmission line for improved RF safety of interventional devices.

A new concept is proposed to improve the safety of transmission lines with respect to heating during RF transmission. It is based on the integration of transformers into the transmission line. The concept was applied to an active tracking device. Miniature transformers were designed, and two types of tracking devices were built based on a standard line and a transformer line. Temperature measurements were performed for both devices during high specific absorption rate (SAR) scanning, and the suppression of RF heating to a physiologically non-relevant level was demonstrated for the transformer device. The transmission properties of the transformer line were examined in simulations and RF measurements. Active tracking with the transformer device performed robustly in the phantom. Because of the favorable signal transmission properties of the tested device, it is expected that the concept can be applied to the construction of clinical devices for tracking and intravascular imaging, which are RF-safe under clinical SAR conditions. Since the transformer line has a large bandwidth, the concept may also be applied for RF-safe transmission of non-MR signals.     

Evaluation of the genetic toxicity of middle distillate fuels

Petroleum middle distillate (PMD) fuels are mixtures of hydrocarbons that distill between ～ 170-370°C. Commercial products that fall into this category include kerosine, diesel fuel, jet fuel, and home heating oil. These products contain both saturated (paraffins and cycloparaffins) and aromatic species, but because of the boiling range normally contain very small amounts of the 3-6 ring polycyclic aromatic hydrocarbon (PAH) constituents, which are considered to be carcinogenic. Nevertheless, there is evidence of weak tumorigenic activity when these materials are repeatedly applied to mouse skin. In the current studies representative products were tested in two commonly used, short-term assays for genetic toxicity, the Salmonella/mammalian microsome mutagenicity assay and the mouse bone marrow micronucleus test. All samples were inactive in the micronucleus assay, and three were clearly inactive in the Salmonella test. Of the remaining two, one was marginally active in the Salmonella assay, and one was equivocal. The marginally active sample contained detectable levels of PAH due to the use of catalytically cracked materials as blending stocks. The results indicated that PMDs that do not contain cracked material were not mutagenic. Thus they may produce tumors via nongenotoxic processes. Those products that do contain cracked stocks may have sufficient PAH to be mutagenic in the Salmonella assay, and in those cases the PAH might also contribute to tumor formation. © 1994 Wiley-Liss, Inc.     

某造船厂高温作业分级调查分析

本文以造船业高温作业分级标准规定，采用室内外温差、劳动时间率指标，参照环境辐射热强度，对某船厂１６个高温岗位进行分级调查，结果是：Ⅱ级占１２．５％，Ⅲ级占６２．５％，Ⅳ占２５．０％，未见Ⅰ级，研究为船厂高温作业分级管理提供了科学依据，并提示船体、铸锻车间中１０个作业岗位是预防高温危害的重点。     

The potential of mild testicular heating as a safe, effective and reversible contraceptive method for men

A preliminary assessment of the contraceptive efficacy of a daily mild increase (1–2°c) in testicular temperature during waking hours is reported in nine couples using two techniques of non-surgical fixation of the testes close to the inguinal canal. With technique 1, immobilization was achieved by passing the penis and the empty scrotum through a hole made in close-fitting underwear; there was one pregnancy, hm a man who stopped the heating after 7 weeks, for 42 cycles of exposure in three couples. With technique 2, immobilization was achieved by adding a ring of soft material surrounding the hole in the underwear; there was no pregnancy for 117 cycles of exposure in six couples. Reversibility and safety were assessed. These preliminary results suggest that a daily mild increase in testicular temperature could be a potential contraceptive method for men.     

Flash‐Heating‐Enhanced Ring‐Opening Polymerizations of ε‐Caprolactone under Conventional Conditions

Summary: Flash conventional heating (FCH) and microwave heating (MH) were matched in their effects on the ROP of ε‐CL catalyzed by Sn(Oct)₂. The temperature of the ROP, heated by a hot salt bath, increased from room temperature to 215 °C within 3 min, which rose a little faster than that by MH (213 °C at 6 min), and the way of heating was considered as FCH. The kinetic results indicate that the chain propagation of PCL was significantly accelerated under FCH conditions and the ratio of the chain propagation rate constant by FCH to that by MH (k/k) was 4.48, if the concentrations of their propagating species were the same. The largest number‐average molar mass ( ) of PCL obtained by FCH was 13.0 × 10⁴ g · mol^?1 at 6 min, but that by MH was 4.1 × 10⁴ g · mol^?1 at 15 min. The ratio of the concentrations of propagating species under the two conditions was around one‐fifth at 4, 6, and 8 min.

Thermal and kinetic behavior of the ROP of ε‐CL.     

Diathermy treatment increases heat shock protein expression in female,but not male skeletal muscle

Heat shock treatments have been used to appreciably increase heat shock protein 70 (Hsp70) content and the phosphorylation of heat shock protein 27 (Hsp27p). The purpose of this investigation was to determine whether diathermy can increase Hsp70 and Hsp27p content in skeletal muscle. Fourteen subjects (7 males and 7 females, 18–35 years) received a muscle biopsy from the v. lateralis and then underwent 20 min of diathermy followed by 20 min of hot pack heating on the contralateral leg. Twenty-four hours following treatment, a second muscle biopsy was performed on the treated leg. All samples were analyzed for Hsp70 and Hsp27p content using western immunoblotting. Images of the blots were obtained and analyzed via densitometry. A paired t-test was used to examine differences in heat shock protein content between the treated and untreated legs. Twenty-four hours following the heat treatment, female subjects significantly (P < 0.05) increased Hsp70 (+58%) and Hsp27p (+100%) content compared to the untreated leg. Male subjects had non-significant increases in Hsp70 (+35%) and Hsp27p (+32%) skeletal muscle content. These results implicate that diathermy can be an effective means to induce Hsp70 and Hsp27p in human skeletal muscle.     

医院太阳能辅助集中供热热水系统的运行策略

介绍了太阳能热水系统概念。以上海市复旦大学附属华山医院新建西院项目为例,阐述了太阳能热水系统工作原理。