Carcinogenic effect of benz(a)pyrene depending on its mode of application to the skin of mice

The role of dose and time factors in intensification of the carcinogenic effect is studied on the model of skin carcinogenesis in (CBA x C57Bl)F1 female mice under application of BP. The total dose is not a single parameter determining the carcinogenic effect. The single dose interval between the actions and their number are of essential importance under definite conditions. The total time (T) of the carcinogen action is a significant factor. The total and single doses and the number of carcinogen applications to the mouse skin being similar, the effect is the stronger, the longer is T, i.e. the longer is the interval between certain applications of the carcinogen.     

Transplacental effect of sodium nitrite on rat lung cells with their subsequent culture in the medium with precursors of N-nitrosodimethylamine

Mongrel rats of 12th day of pregnancy were administered sodium nitrite, amidopyrine, mixture of these substances and N-nitrosodimethylamine (NDMA) as well as alpha-tocopherol + ascorbic acid with drinking water. The cultivated lung cells of 3-day newborn rats with NDMA and its precursors were incubated. The transplacental effect of sodium nitrite on rat lung cells was observed. It was manifested in a decrease of the cell suspension viability, in an increase of the pathological mitosis level as well as in changes in cell responses to NDMA. The combination of sodium nitrite with phenobarbital considerably increased sensitivity of cells to the effect of NDMA, mixture of sodium nitrite with amidopyrine and amidopyrine.     

Biological characteristics of rat lung cells cultured in a medium with N-nitrosodimethylamine precursors

Lung tissue culture of 3-day old rats was cultivated in the presence of sodium nitrite, amidopyrine and combination of these substances with N-nitrosodimethylamine (NDMA). Each of these compounds produces specific changes in monolayer density, mitotic patterns and level of DNA synthesis in lung cell culture, which is considered to be convenient model for investigating cell response to the precursors of NDMA and to this carcinogen.     

Effect of vitamin A on the endogenous synthesis and system of N-nitrosodimethylamine detoxication in the rat liver

The administration of N-nitrosodimethylamine (NDMA) and its endogenic synthesis from amidopyrine and sodium nitrite decreases in the liver the level of reduced glutathione, ascorbic acid, glutathione reductase and glutathione-S-transferase activities, the accumulation of oxidized glutathione as well as the damage of DNA. The gamma-glutamyltransferase activity, the marker of carcinogenesis, increased. The damaging action of NDMA under the influence of vitamin A deficiency increased, but the vitamin excess decreased the biochemical changes in the liver.     

DNA alkylation during endogenous synthesis of N-nitrosodimethylamine

The simultaneous administration of 14C-dimethylamine and sodium nitrite to rat stomach produces the formation of O6-methylguanine and 7-methylguanine in the liver DNA as a result of the endogenic synthesis of N-nitrosodimethylamine (NDMA). Methylation of DNA was also observed in the rat kidney and lung. Alkylation of O6-position of guanine and removal of its methylated product from the DNA occurred in the liver to a greater extent than in the other NDMA target organs. Pretreatment of rats with sodium nitrite increased the alkylation of liver DNA caused by endogenic synthesis of NDMA. The formation of alkylated products in DNA may be used as a marker for the endogenic formation of NDMA from precursors.     

Damage to the liver DNA of rats during the endogenous synthesis of N-nitrosodimethylamine

The damage of liver DNA formation during endogenic synthesis of N-nitrosodimethylamine (NDMA) have been studied after introduction of its precursors, dimethylamine, amidopyrine and sodium nitrite, into the rat stomach. A combined administration of various doses of dimethylamine and nitrite increased the amount of single-strand DNA from 3.0 to 11.3%. The maximum DNA damage after administration of the precursors was observed after 24 h, and after 48 h it decreased to the control level. Pretreatment of rats with dimethylamine or nitrite increased the DNA damage induced by NDMA formation (37.4% and 41.6%, respectively).     

Carcinogenic properties of silicon carbide whiskers

In experiments with intrapleural injections of silicon carbide whiskers (20 mg X 3, with one month interval) to random-inbred rats their carcinogenic activity close to that of chrysotile B UICC has been established. The pleural mesotheliomas were induced in 47.7 and 34.1% of rats, respectively.     

Carcinogenic activity of some Soviet drug preparations

After the long-term administration of doxilane-diolane, cresacin, antioxidant S-1 and fluorine varnish to mongrel albino rats and mice no difference in the level of spontaneous tumours both in the control and experimental groups of animals was observed. It is concluded that these drugs possess no carcinogenic activity.     

Cut-and-paste customization of organic FET integrated circuit and its application to electronic artificial skin

The concept of cut-and-paste customization is introduced for the first time in designing integrated circuits based on mechanically flexible organic field-effect transistors, and is applied to electronic artificial skin. The electronic artificial skin comprise of three separate integrated circuits that are a pressure-sensor array, row decoders, and column selectors to read out pressure information over a large area. All of three integrated circuits are scalable in size because the pressure-sensor array is a simple repetition of sensor cells and the row and column decoders adopt wired-NAND circuits, which enables the cut-and-paste customization in size. The physical cut-and-paste procedure is employed by cutting a part of the integrated circuits and pasting it to another integrated circuit with a connecting plastic tape. The integrated circuits are designed with a standard SPICE simulator and layout design tool, and the operation is confirmed by measurement.     

Integral equation solution to the skin effect problem in conductorstrips of finite thickness

The skin effect of single and coupled conductor strips of finite thickness is analyzed using the dyadic Green's function and the integral equation formulation. Galerkin's method is used to solve the integral equation for the dispersion characteristics. The effects of the geometrical and electrical parameters on the conductor loss are investigated. Results are compared with previously published data and shown to be in good agreement. This approach is very useful for analyzing the electrical properties of interconnects in high-performance computer circuitries     

钕玻璃激光治疗皮肤色素性疾病及组织学改变的观察

我科应用钕玻璃激光治疗色素性皮肤病188例，取得较好疗效，并就钕玻璃激光对皮肤病损组缓和正常皮肤组织损伤的组织学改变进行了观察，现报告如下：     

早期降眼压药物对高度近视术后屈光回退影响的研究

目的：探讨早期应用降眼压药物噻吗洛尔对高度近视术后屈光回退的影响。方法：将高度近视患者41例（81眼）LASIK手术后分为两组：常规组和噻吗洛尔组,分别于术前和术后1m、3m、6m、12m检查裸眼视力、屈光度、角膜前表面曲率等指标,比较分析并计算屈光回退率。结果：两组术后随着时间的推移,屈光回退率及角膜前表面曲率值均有增加,但用药组回退率及曲率增加值在术后1m、3m、6m、12m分别低于常规组,差异有统计学意义（P〈0.05）。结论：早期应用降眼压药物能够较好的降低高度近视术后屈光回退,稳定手术效果。     

Carcinogenic action of 5-methoxytryptamine related to its transformation into 5-methoxyindolyl-3-acetic acid

A considerable blastomogenic effect of metabolite serotonin 5-methoxytryptamine (5-MOT) subcutaneously administered for a long time to C57BL/6 mice was established. This effect was decreased noticeably if the further metabolism of 5-MOT into 5-methoxyindolyl-3-acetic acid (5-MIAA) was blocked by pyrazidol. These results explain the fact that the blastomogenic effect of 5-MOT is not direct but is caused by the transformation of 5-MOT into its final carcinogenic metabolite 5-MIAA.     

Time domain analysis of skin effect on lossy interconnections

A new skin effect equivalent circuit has been presented in a previous work (1990) where the ground plane has been considered as a perfect conductor. In this letter, the loss due to the returning current in a resistive ground plane is accounted for. A modified skin effect equivalent circuit is presented and analysed by SPICE to obtain the propagation parameters as a function of frequency. This equivalent network is analysed in the time domain. Responses obtained have good agreement with those given by other methods.<>     

Modal network theory of skin effect in flat conductors

A new theory of skin effect in linear conductors of arbitrary cross-sectional shape is proposed and illustrated by calculating the ac resistance of a flat conductor. The current flowing in any conductor may be decomposed into an infinite set of normal mode currents, all of which exist independently of each other. Each modal current may be calculated from the conductor terminal conditions by simple circuit theory. Use of this method presupposes knowledge of the normal modes, which are different for every cross-sectional shape. A general method of finding the normal modes is given. Excellent agreement with experimental data is reported.     

M-CCCH应用与效果分析

随着GSM数据业务的迅猛发展,现网增加了大量的寻呼和立即指配,已对公共控制信道造成了一定的影响,进而引起网络质量问题.本文分析了M-CCCH原理并对M-CCCH配置提出了计算方法,并在实际网络中的应用效果进行了分析.     

多脉冲激光辐照皮肤组织的光热效应实验研究

通过实验测定了离体乳猪皮肤组织在多脉冲Nd:YAG激光辐照下径向和轴向不同位置的温度分布,重点研究了激光辐照能量密度、脉冲重复频率以及波长对皮肤组织温升分布的影响.研究结果表明:皮肤组织中的温度分布与探测位置、激光辐照能量密度、脉冲激光的重复频率以及波长密切相关;在激光辐照时间为40 s的情况下,同一波长同一频率时组织温度随能量密度的增加而增大,波长1064 nm、霞复频率10 Hz时的安全光剂量阈值为1118.19 mJ/cm2;同一波长同一能量密度时,组织温度随脉冲激光重复频率的增加面增大;同一能量密度同一频率时,波长为1 064 nm的多脉冲激光辐照皮肤组织时的光热效应较532 nm波长明显.     

"猫眼"效应及其应用

本文对“猫眼”效应的研究进展作了综述,介绍了目前存在的几种“猫眼”效应模型,并推导出由于光敏面的离焦引起的发散角。对“猫眼”回波功率和漫反射小目标回波功率之比的物理意义作了解释。最后对“猫眼”效应应用中的一些问题作了讨论。     

He-Ne激光加蒽林软膏对家兔皮肤影响的研究

本文研究He-Ne激光加蒽林对家兔皮肤的作用,以寻求一种能促进毛发迅速生长又无毒副作用的方法。 取青紫蓝灰及黑毛家兔72只,体重1.5～2.5kg。采用HNZSQ-2型He-Ne激光治疗仪,波长632.8nm,输出功率25mW。自配蒽林软膏(Arthralin),浓度为0.01％和0.25％两种。     

Enhanced skin effect for partial-element equivalent-circuit (PEEC)models

In this paper, a skin-effect modeling approach is presented that is suitable for all frequency regimes of interest and therefore is most appropriate for transient interconnect analysis. Yet, the new formulation lends itself to a model that can be abstracted for use in conjunction with surface integral and finite difference-based electromagnetic tools for interconnect modeling. While a volume filament technique is not computationally feasible at high frequencies, where a fine discretization is necessary, the formulation that is presented avoids this difficulty by carefully casting the behavior of a conductor into the form of a global surface impedance, thus requiring fewer unknowns. Several examples illustrating the ability of the proposed model to accurately capture proximity and skin-effect behaviors will be shown, Interconnect resistance and inductance per-unit-length results are given and compared with those obtained using different models