Methods : 1 ) 12h after irradiation , the cell cycle of nih3t3 cells was determined by flow of cytometry and the ratio of alternations in p16 gene exon - 2 was evaluated through pcr - sscp . 2 ) the content of mda , the activities of the sod and gsh - px in the supernatant of nih3t3 cells and the cells were measured by detecting kits immediately after irradiation . 3 ) the level of matrix metalloproteinase - 2 ( mmp - 2 ) in hela cells was detected by western - blotting and dot - blotting 2h after irradiation 具体方法为： ( 1 )照射后12h ，收集nih3t3细胞，用流式细胞仪检测各组细胞的细胞周期， pcr - sscp检测抑癌基因p16的变化； ( 2 ) nih3t3细胞照射后立即收集细胞和细胞上清，用试剂盒测量mda含量和sod 、 gsh - px的活性并观察其变化； ( 3 ) western免疫印迹和点杂交法检测照射2h后的各组hela细胞中基质金属蛋白酶- 2 ( mmp - 2 )的表达变化。
The experiment includes two procedure . first , sd rats were conditioned with 5 . 5gy sublethal total body irradiation ( tbi ) , followed by infusion of balb / c mice bone marrow cells 8x107 on day 0 , then were intraperitonially administered cyclophosphamide ( cp ) 150mg / kg on day 2 . the procedure let sd rats become chimerism and have specific immunologic tolerance 实验分两步：第一步， sd大鼠经亚至死剂量5 . 5gy全身照射后，尾静脉输入balb c小鼠的骨髓细胞8 10 ~ 7 ， 2天后腹腔内注射环磷酰胺150mg kg ，诱导形成嵌合体大鼠，使其对balb c小鼠产生特异性免疫耐受。
The preliminary results as follows : - different doses ir induced gl / s cell cycle checkpoint in hela cells cyclin e / cdk2 kinase activity in hela cells decreased at ih , then increased at 3h , reached maximum at 12h exposed to2 gy - irradiation ; but its activity upregulation started at ih , and reached maximum at 12 h exposed to logy irradiation R )对细胞周期g1 / s检查点的影响cycnne / cdkz激酶活性在zgy照射后lh略有下降， 3h略有回升， 12h活性达到最大; 10gy照射后其活性从lh开始增加， 12h活性达到最大。
When various diameter particles are irradiated by a collimated laser light beam , light scattering phenomenon takes place , and the scattering light parameter include the information of the particles size distribution . mie scattering theory is the fundamental principle of the particle size measuring instruments and its computations are complicate 微型化雾粒粒径分布测量仪的测量原理是米氏光散射理论，当不同粒径的颗粒被平行激光束照射后，发生光散射现象，散射光的参数包含有被测颗粒粒径的信息，但其数值计算量大且复杂。
Ion objective : to investigate effect of nd : yag laser irradiating root canals on periapical tissue . methods : three minipigs were used in this study , deciduous premolars were opened , pulps were extracted , root canals were enlarged , then irradiated with nd : yag laser 30s and filled conventionally . the changes of periapical tissue were observed after 1 , 3 , 7 and 15 days . results : after one day , periapical tissue showed enlargement and engorgement of blood vessel and a few of leukocyte , the changes were more serious than in control . after 3 and 7 days , there were minor reactions in periapical tissue and same as the control group . after 15 days , periapical membrance in most specimens was normal . slight inflammatory reaction was found in the test group as same as in control group . conclusion : there was little damage to periapical tissue with the laser irradiation 目的:观察激光在根管内照射后对根尖周组织的作用.方法:选3只小型猪,全麻下将乳前磨牙开髓、抽髓,根管扩大后,激光照射30秒,做常规根管充填.对照组为常规根管充填. 1天、 3天、 7天和15天后观察根尖周组织的变化.结果:激光照射后1天,根周膜血管充血、轻度炎症,对照组只有根尖周膜充血.激光组组织反应比对照组稍重.激光照射后3天和7天,少数病例根周组织有轻度的刺激与对照组的病理表现相近.激光照射后15天部分标本根周膜正常,部分标本有轻度炎症反应,与对照组结果基本相似.结论:本激光照射条件对根尖周组织没有明显损伤作用,可供临床应用时参考
After several decades " improvement in technology and accumulated experience in clinical use , more and more intracranial tumors have been treated with this unit , but the detailed mechanisms are not understood about its neuroradiobiological effects , especially the early or acute damage and time - dependent changes of neural cells in the target and surrounding brain regions 经过几十年的临床经验的积累和技术的改进，放射治疗已经成为颅脑肿瘤的重要治疗手段之一。但迄今对于电离辐射神经放射生物学的基础研究尚不足，尤其对于照射后靶区及其周围组织早期或急性期的损伤程度及时程变化缺乏系统的动物实验研究，本实验目的即在于此。
The protein level of p21 increased lightly from 1 to3 h , then decreased at 6 - 9 h , reached maximum at 24 h after 2gy , it increased from 3 to 24 h exposed tology , and the protein level of p21 associated with cdk2 increased , which did not inhibit the cyclin e / cdk2 kinase activity , because of upregulation of cyclin e and deregulation of p27kipl after irradiation . in contrast to p21 , p27kipl may be a key regulator of cyclin e / cdk2 activity in dna damage responses . hi the ubiquitin - proteasome pathway invovled in regulation of p27kiplexpression in response to ir the ubiquitin - proteasome pathway regulated selective and time - controlled elimination of p27 kipl 与p27ki ” ，表达水平不同， pzi蛋白表达水平在zgy照射后略有增加， 6一gh略有下降，在照后24h达到最大; 10gy照后1一3h开始增加，持续到24h ，并且cycline / cdkz复合物中pzi蛋白结合增多，但cycline / cdkz激酶活性并未受到抑制，除了因ir诱导cydine蛋白表达水平增加外，另一重要的原因就是与pzi同一家族的p27kip ，蛋白表达水平下降，失去了对cycline / cdkz的抑制活性。
It is based on the principle : under a number of angles , the x - ray attenuation in a cross section of a human body is measured by detector resulting in a set of profiles . this set of profiles is called the radon transform of the object in mathematics . the problem now is to reconstruct a two - dimensional image via inverting its radon transform 它所基于的成像原理是：人体的某个剖面在若干个角度上被x射线束照射，照射后x射线的衰减量被检测器记录下来，形成投影集合，数学上将这个投影集合描述为该剖面的radon变换，通过反演radon变换就能够重建剖面的二维图像。
Only a few patients , especially those who have received large dosage of radiation at a time , may have some side effects , such as , headache , naupathia , vomit , fever and so on . it is mostly caused by damage of capillary vessel , edema or infection due to radiation . however , the side effects just lasts a short period of time and they can disappear more quickly with the assistant of medicines such as dehydrator 少数病人特别是接受单次较大剂量照射的病人可能会出现一些副反应，如照射后几天内出现轻度头痛恶心呕吐发烧等，这多半是由照射引起的毛细血管损伤水肿和炎性反应，时间短暂，一般都可自行恢复正常，适当用一些药物如脱水剂等治疗，效果更佳。
Computerized tomography ( ct ) is a typical non - invasive examination techniques in medicine , which can depict anatomical structures without damaging the human body . lt is based on the principle : under a number of angles , the x - ray attenuation in a cross section of a human body is measured by detector resulting in a set of profiles . this set of profiles is called the radon transfoim of the object in mathematics . the problem now is to reconstruct a two - dimensional image via inverting its radon transform 它所基于的成像原理是：人体的某个剖面在若干个角度上被x射线束照射，照射后x射线的衰减量被检测器记录下来，形成投影集合，数学上将这个投影集合描述为该剖面的radon变换，通过反演radon变换就能够重建剖面的二维图像。
