γ-射线辐照对淋巴细胞杀伤效果的研究

目的 确定抑制淋巴细胞增殖所需的最低辐照剂量。方法 分别用 5、15、2 5、35、5 0Gy 5种剂量对血液进行辐照处理 ,然后进行混合淋巴细胞培养 (MLC)及有丝分裂原刺激试验 ,测定3 H掺入量以测定淋巴细胞的残存增殖活性。结果 与未辐照血相比 ,15Gy剂量辐照时 ,对MLC培养的抑制率已达 (96 .4± 2 .0 ) % ,但对PHA刺激和ConA刺激反应的抑制率分别为 (85 .0± 1.7) %和 (86 .5± 5 .1) % ,均低于 95 % ;2 5Gy剂量辐照时 ,对PHA刺激和ConA刺激反应的抑制率分别达 (96 .3± 2 .8) %和 (96 .6± 4 .3) %。结果 15Gy剂量不足以预防TA GVHD ,最低辐照剂量应为 2 5Gy。

莪术油对鼻咽癌CNE-2细胞的凋亡及放疗增敏机制的影响

目的探讨莪术油、莪术油联合γ-射线照射对鼻咽低分化鳞癌细胞株CNE-2的增殖抑制和诱导凋亡作用;分析莪术油是否具有放疗增敏的作用,并研究其机制。方法体外培养CNE-2细胞,莪术油以体外直接加药的方式作用于CNE-2细胞,采用MTT、流式细胞术、电镜等分子生物学手段,检测莪术油单用或联合γ-射线对CNE-2的诱导凋亡作用、放疗增敏作用。结果莪术油单独使用,对CNE-2细胞有确切的增殖抑制及诱导凋亡作用,并与常规化疗药物5-Fu有相近的抑制作用(P>0.05)。莪术油的药物抑制作用呈现浓度依赖性,最低起效浓度为10μg/ml,最佳作用时间为48小时;5μg/ml、100μg/ml、300μg/ml的莪术油联合100cGy的γ-射线作用2天后凋亡率由0.5%、2.15%、10.2%显著提高到8.6%、14%和26%,细胞的死亡率均在5%以下有明显的协同增效作用(P<0.01);联合作用96h后试验组的细胞主要以死亡为主,凋亡较少;500μg/ml的莪术油主要导致细胞死亡,有明显的细胞毒性。流式细胞仪结果显示较高浓度时,莪术油使CNE-2细胞阻滞在G1期。电子显微镜观察细胞凋亡的超微结构可以看到凋亡小体。结论莪术油可以抑制鼻咽癌细胞CNE-2的增殖并诱导其凋亡;莪术油和100cGy的γ-射线联合作用有明显的增敏作用;其作用机制与诱导肿瘤细胞发生凋亡及影响细胞生长周期有关。

Efficient Extraction of Tea Saponin from Tea Seed Meals by ^(60)Coγ-Irradiation

In order to simplify the extraction process of tea saponin and improve its extraction rate,tea seed meals was taken as materials to explore effects of ^(60)Coγ-irradiation and H_(2)O_(2) on the extraction rate of tea saponin.The results showed that the optimal crude extract condition of tea saponin was 6%H_(2)O_(2) and an irradiation dose of 5 kGy,the extraction rate was 46.4%.However,when the irradiation dose and the H_(2)O_(2) concentration continued to increase,the extraction rate of tea saponin decreased.After flocculate extraction,the tea saponin content increased from 40.80%to 48.32%.Foaming property test results showed that the higher the tea saponin content in the solution was,the higher the foaming height will be,and the foam had a certain stability.This work provided a new method for the extraction of natural products,usingγ-ray irradiation and H_(2)O_(2) pretreatment to improve the extraction rate,and this was of great significance for industrial extraction.

Radiation-Chemical Degradation of Oxalic Acid in Water Solutions

Co60 gamma ray radiolysis of aqueous oxalic acid solution （1 × 10-2 M） was investigated within the dose range up to 80 kGy. The value of pH increases from 2.0 to 4.0 and approximately 90% of oxalic acid and its derivatives are degraded at the dose of 80 kGy. Dissolved O2 affects to the degradation of oxalic acid at the initial stage due to total consumption of O2 at the dose of 2 kGy. Formation of CO2 occurs at a higher rate at the initial stage until the dissolved 02 is fully consumed. The kinetic model of oxalic acid degradation in aqueous solution under the gamma irradiation was tested. The suggested mechanism complies with the experimental data both of our own and of that reported earlier.

Effects of Hypofractionated and Standard Fractionated Irradiation of Mice Heads with Gamma-Rays and Protons on Their Pheripheral Blood Parameters and Behavior

Experiments were performed to study the action of fractionated irradiation of mice heads with γ-rays and protons on their peripheral blood parameters and behavior by the ＂Open Field＂ test. Mice were irradiated in two variants of fractionated irradiation： （1） traditional fractionation （in radiation therapy）： 2 Gy once a day, 5 times a week, the total radiation dose 20 Gy; （2） extreme hypofractionation： 10 Gy once a week, on Mondays, the total radiation dose 20 Gy. The results of the study showed that irradiation of mice heads has no effect on their peripheral blood parameters in both variants of the applied fractionated irradiation and the behavior of mice does not depend on the type of ionizing radiation and the variant of fractionated exposure that we used. On the basis of these results it can be concluded that the option of extreme hypofractionation we have chosen can successfully replace traditional fractionation, which in some cases is applied when carrying out radiotherapy for treating brain tumors. The application of this type of fractionation can lead to shorter terms of radiotherapy and bigger patient capacity of medical centers that conduct radiotherapy.

Objects Obtained by y Quanta Irradiation with Threshold Energy of 10 MeV of Pure Gaseous He, under High Pressure, in CuBe2 Apparatus

A HeHPC （Helium high pressure chamber） filled up with pure gaseous helium at initial pressure about 1.1 bar was irradiated by braking γ-rays of 10 MeV threshold energy during 1.0 × 10^5 s at the electron beam current 22 - 24 μA. After irradiation, the residual pressure inside was equal to 430 bar. Synthesized foils of black color and other multiple objects were found inside the HeHPC mainly at the entrance window for γ-rays made from beryllium bronze as a plug of beryllium bronze HPC, at the inner surfaces of the reaction chamber made of high purity copper and at the copper collector. The element analysis, using SEM （Scanning electron microscopy） and MPRA （Microprobe roentgen analysis）, allowed us to establish that the foils consist predominantly of carbon and the smaller quantities of other elements from carbon to iron. An explanation for the observed elements is suggested on the basis of helium fusion reactions under the action of y-rays with the reactions taking place in giant stars （thermally activated）. The possible mechanism after 3α reaction is nα reactions and under barrier reactions. A second experiment with initial pressure of 3.05 kbar （with pressure drop by about 65 bar - after almost the same procedure of y-rays irradiation and with fully beryl bronze environment） suggests another possible nuclear reactions - He（Be, p）C, He（C, γ）O, and so on. The developed approach agrees well with a series of studies carried out by the authors where dense hydrogen and deuterium gases are acted on by γ-rays in the presence or absence of metals in the reaction chambers.

Improvement of Rice （Oryza sativa L.） var. Ciherang and Cempo Ireng Productivity Using Gamma Irradiation

Rice is the source of important food in the world. The demand of rice tends to increase every year, thus research to increase genetic variation of rice by gamma irradiation has been conducted. This research aimed to study the influence of gamma irradiation doses on the vegetative growth, yield and quality. The randomized completely block design was used with two factors --gamma irradiation doses and varieties. Two rice varieties were Ciherang and Cempo Ireng, while doses of gamma irradiation consisted of six levels： 0, 100, 200, 300, 400 and 500 Gy. The results indicated that the treatment of 200 Gy gamma irradiation to Ciherang could improve the number of grains/panicle, protein content, degraded plant height and amylose contents. Gamma irradiation to Cempo Ireng at dose of 200 Gy could improve the number of grains/panicle, 1,000 grain weight, while it decreased days to 50% heading and plant harvest age.

White spot syndrome virus inactivation study by using gamma irradiation

The present study was conducted to investigate the effect of gamma irradiation on white spot syndrome virus （WS SV）. White spot syndrome virus is a pathogen of major economic importance in cultured penaeid shrimp industries. White spot disease can cause mortalities reaching 100% within 3-10 days of gross signs appearing. During the period of culture, immunostimulant agents and vaccines may provide potential methods to protect shrimps from opportunistic and pathogenic microrganisms. In this study, firstly, WSSV was isolated from infected shrimp and then multiplied in crayfish. WSSV was purified from the infected crayfish haemolymph by sucrose gradient and confirmed by transmission electron microscopy. In vivo virus titration was performed in shrimp, Penaeus semisulcatus. The LD50 of live virus stock was calculated 1054/mL. Shrimp post-larvae （1-2 g） were treated with gamma-irradiated （different doses） WSSV （10^o to 10^-4 dilutions） for a period of 10 days. The dose/survival curve for irradiated and un-irradiated WSSV was drawn; the optimum dose range for inactivation of WSSV and unaltered antigenicity was obtained 14- 15 kGy. This preliminary information suggests that shrimp appear to benefit from treatment with gamma- irradiated WSSV especially at 14-15 KGy.

ASSESSMENT OF COLLECTIVE DOSE FOR TRAVELLERS BY WATERS

People travelling by air will receive more exposure dose and by water will receive less one.According to statistic data from the Ministry of Communications in 1988,the turnover in that year was abode 2×1010 man·km.The total number of fishermen for inshore fishing was nearly two million reported by Ministry of Agriculture,Animal Husbandry and Fishery.Based on measured data on 212 points in six typical shipping lines of inshore lines and inland rivers,and the total voyage is 5625km,the average natural radiation dose rate received by travellers was calculated.Worn that assessment of collective effective dose for passengers by Water and fishermen was derived.The value is 32.7 man.Sv for passengers and 265.3 man.Sv for fishermen.

The Effectiveness of Radiation Damage Reduction in Mice by Laser Light in Dependence of the Time Interval between Exposures

A research was carried out to determine the period of time during which it is possible to reduce the radiation damage in mice by means of laser radiation （650 nm） after gamma irradiation. First, the mice were exposed to γ- radiation （whole body irradiation）, then after 2 h or 24 h they were irradiated with laser radiation. The results of these studies have shown that the use of laser irradiation to reduce radiation damage in mice is effective 24 h after the exposure to 5 Gy ionizing radiation which leads to the bone-marrow clinical form of the ARS （Acute radiation sickness）. In case of the lethal dose of ionizing radiation 7 Gy （the transitional clinical form of the ARS）, the increase in life expectancy of mice is observed using laser radiation both 2 and 24 h after the exposure to γ- radiation, but the effectiveness of the laser used 2 h after the ionizing radiation is significantly more efficient.

Biocidal Effect of Gamma Radiation on the Ecology of Filamentous Fungal Populations Associated with Stone Deterioration

This study focused on the identification of the filamentous fungi associated with soapstone samples exposed to outdoor conditions and the biocidal effect of gamma radiations on isolated fungal populations in Minas Gerais State in Brazil. Two soapstone blocks were placed outdoors under tropical environmental conditions for 12 months. A total of 9 filamentous fungal populations were identified on their surfaces, namely Acremomium （cf.） alternatum, Alternaria alternata, Aspergillusfumigatus, Calcarisporium （cf.） arbuscula, Cladosporium cladosporioides, Curvularia lunata, Epicoccum nigrum, Fusarium equiseti and Penicillium citrinum. The gamma radiation assay was then carried out as a test of biocidal action by exposing all fungal populations to the ionizing radiation. The results showed that only the C. cladosporioides species was resistant to this biocidal agent, since it was able to increase its population post exposure. Scanning electron microscopy images identified the microbial colonization on the soapstone blocks and the stone elementar composition was analyzed by energy dispersive X-ray spectrometry. After treatment, there was no structural and aesthetic alteration in the soapstone samples, and evidencing that gamma radiation can be used as a biocidal agent. However, the resistance of the black fungal population indicates caution in the choice of gamma irradiation as biocidal treatment.

Thermoluminiscence Response of an Alloy Quaternary Ionic Crystal Exposed to High Energy Radiation

The alkali halide crystals exhibit significant TL （thermoluminescence） properties when exposed to ionizing radiation. The defects in crystals can be produced in high concentration by means of chemical impurities, radiation, mechanical work and others processes. This study is concerned with the TL properties of quaternary mixtures of alkali halide crystals when they are irradiated with beta and gamma-rays. The samples were made mixing KCI, KBr, RbCI, RbBr salts doped with divalent europium （Eu2＋）, by the Czochralski method sintering at 400 ~C during 6 hours in a N2 atmosphere. The samples were exposed to beta and gamma rays. We present the TL glow curves, demonstrating that the nature of the defects in the crystals can be produced by trapping states and recombination mechanisms. The highest temperature TL curves are the most interesting due to possible applications in dosimetry and optical energy storage.

The Best Dose for Sterilisation of Greenhouse Whitefly, Trialeurodes vaporariorum （Westwood） （Hem.： Aleyrodidae） by Gamma Radiation

Greenhouse whitefly （GHWF）, Trialeurodes vaporariorum （Westwood） is a very important pest of greenhouse plants, but its resistance to pesticides has rendered it difficult to control by chemical methods in recent years. Sterile insect technique （SIT） is a biological control method which has been used in Area Wide Integrated Pest Management （AWIPM）. This study conducted the possibility of sterilising GHWF adults by gamma radiations emitted from cobalt 60. Longevity of the adults, and the amount of egg laying and sterilisation of eggs were determined under the influence of 50, 60, 70, 80, 90 Gy doses under controlled conditions （65 ± 5% RH, 25 ± 2 ℃, L/D = 16/8）. Normal insects were considered as control （0 dose）. The best combination for mating of normal and sterile adults （normal male × normal female as control, normal male and irradiated female, irradiated male × normal female, and irradiated male × irradiated female） was studied using a factorial design （n = 4）. Results showed that the best irradiating doses were 70 and 80 Gy for females and males respectively. Longevity of irradiated males and females was not significantly different from that of non-irradiated specimens. The best mating model was irradiated males and females.

Study of latch-up immunization in bulk CMOS integrated circuits exposed to transient ionizing radiation

This paper presents experimental results of transient gamma irradiation effects on two kinds of circuits.One is a two-stage circuit consisting of a bipolar power device L7805CV and a bulk complementary metal-oxide-semiconductor(CMOS) device IDT6116,the other is a two-stage circuit consisting of a bipolar power device L7805CV and the equivalent circuit of the parasitic P-N-P-N structure in bulk CMOS devices.The results show that the L7805CV's output interruption after transient irradiation can prevent latch-up from occurring on the second stage circuit.The demanded minimum interruption duration to avoid latch-up varies with dose rate,and this is confirmed by the experimental results.

Highly pressure-sensitive graphene sponge fabricated by γ-ray irradiation reduction

Graphene sponge(GS) with microscale size, high mechanical elasticity and electrical conductivity has attracted great interest as a sensing material for piezoresistive pressure sensor. However, GS offering a lower limit of pressure detection with high gauge factor, which is closely dependent on the mechanical and electrical properties and determined by the fabrication process, is still demanded. Here, γ-ray irradiation reduced GS is reported to possess a gauge factor of 1.03 kPa^–1 with pressure detection limit of 10 Pa and high stress retention of 76% after 800 cycles of compressing/relaxation at strain of 50%. Compared with the carbon nanotube(CNT) reinforced GS, the improved lower limit of pressure detection and gauge factor of the GS prepared by γ-ray irradiation is due to the low compression stress(0.9 kPa at stain of 50%). These excellent physical properties of the GS are ascribed to the mild,residual free, and controllable reduction process offered by γ-ray irradiation.

Effects of Gamma Irradiation for Sterilization on Aqueous Dispersions of Length Sorted Carbon Nanotubes

There is currently great interest in the potential use of carbon nanotubes as delivery vessels for nanotherapeutics and other medical applications. However, no data are available on the effects of sterilization methods on the properties of nanotube dispersions, the form in which most medical applications will be processed. Here we show the effects of gamma irradiation from a 60Co source on the dispersion and optical properties of single-wall carbon nanotubes in aqueous dispersion. Samples of different length-refined populations were sealed in ampoules and exposed to a dose of approximately 28 kGy, a level sufficient to ensure sterility of the dispersions. In contrast to literature results for solid-phase nanotube samples, the effects of gamma irradiation on the dispersion and optical properties of the nanotube samples were found to be minimal. Based on these results, gamma irradiation appears sufficiently non-destructive to be industrially useful for the sterilization of nanotube dispersions.