低剂量辐射(low-dose radiation,LDR)生物效应仍然是放射生物学领域的研究热点.随着研究的深入,对LDR产生的各种生物效应及其机制不断完善.越来越多的证据表明,LDR诱导的生物效应和高剂量辐射不同,这些研究对"线性无阈"模型提出质疑.本文从LDR诱导的旁效应、兴奋效应、适应性反应以及低剂量辐射超敏感性及其相应的机理进行综述,以期为LDR生物效应的研究从基础研究到临床应用的转化提供参考.

目的:观察3D打印种植体与经典Straumann种植体植入家兔体内后骨整合情况,为其临床应用提供理论依据.方法:以3D打印的方法制作Ti-6Al-4V(TC4)种植体,以经典Straumann种植体作为对照,于6只家兔双侧股骨植入种植体建立家兔种植体模型,每侧各植入1颗TC4种植体和1颗Straumann种植体,共12颗TC4种植体(TC4种植体组)和12颗Straumann种植体(Straumann种植体组).术后2、4和8周各处死2只家兔,取出种植体周围组织,甲苯胺蓝染色观察成骨细胞、新骨形成及骨组织修复情况,亚甲基蓝-酸性品红染色观察新骨形成及矿化情况,扫描电子显微镜(SEM)观察术后TC4种植体表面结构变化,采用能量色散X射线光谱仪(EDS)对术后TC4种植体进行元素构成分析.结果:甲苯胺蓝染色,术后2周时,2组紧贴种植体的骨组织边缘有胞核深染、胞浆呈淡蓝色的成骨细胞线性排列;术后4周,2组种植体周围骨组织存在淡染的新生胶原纤维样结构,排列欠整齐;术后8周,2组家兔靠近种植体一侧骨组织可见淡蓝色、结构连续的新生骨形成,内含大量骨细胞,新生骨与原矿化骨界限清晰.亚甲基蓝-酸性品红染色,术后2周,2组种植体周围骨组织中有活跃的成骨细胞聚集;术后4周,2组种植体与原矿化骨组织间均可见新生的、红染的类骨质结构;术后8周,2组种植体表面均可见伴有一定程度钙化的新生骨形成,呈深红色,Straumann种植体组钙化程度略优于TC4种植体组.SEM观察,完成体内实验的TC4种植体在表面结构上基本与术前TC4种植体保持一致,未见明显结构缺损形成.EDS扫描分析,完成体内实验的TC4种植体除含有与术前TC4种植体一致的元素外,尚存在常量元素钙(Ca)、锰(Mg)和微量元素硅(Si)等.结论:3D打印TC4种植体具备良好的结构稳定性与生物相容性,在体内可以达到与Straumann种植体相似的骨结合.

为减少日益增长的交通安全问题,车辆碰撞预警及避碰控制系统必不可少.本文提出了一种结合车辆横纵向动力学的复合控制避碰方法,以达到减少交通事故发生的目的.首先,分别建立了车辆逆纵向和横向动力学模型,纵向控制器通过安全距离模型来判断车辆是否处于危险状态并进行碰撞预警,采用分层控制方法设计了上层模型预测控制器和底层单神经元PID控制器.横向上结合不同时速时的参数约束设计模型预测控制器.最后,在不同工况下进行了仿真实验,表明本文控制系统能成功避碰,提高了车辆的安全性、稳定性、舒适性.

N 6-methyladenosine (m 6A) is the most abundant RNA base modification in mammals, especially in eukaryotic messenger RNA (mRNA). N 6-methyladenosine modification can regulate RNA splicing, translocation, stability and ultimately affect protein synthesis. m 6A modification is catalyzed by RNA writers, reduced by erasers and also be recognized by readers. Abnormal changes ofm 6A levels are closely related to tumor occurrence and development, including proliferation, growth, invasion and metastasis. In the process of tumor radiotherapy, m 6A modification affects the efficacy of radiotherapy by affecting DNA damage, tumor stem cell generation and tumor cell radiation sensitivity. This article reviews the role of m 6A-modified epigenetic regulation in malignant tumors and the research progress of its mechanism in tumor radiotherapy, in order to provide new ideas for the development of clinical tumor molecular targeted therapies and radiosensitizers.

Objective:To investigate the effects of the differentiation of regulatory T cells (Tregs) on radiation-induced lung injury and its mechanism.Methods:A mouse model that inhibits Tregs was established. C57BL/6 mice were divided into the control group, simple irradiation group, irradiation+IgG group, and irradiation+CD25 group according to the random number table method. Each group comprised 12 mice. The mice in the simple irradiation group, irradiation+IgG group, and irradiation+CD25 group were given a single 20 Gy X-ray full chest irradiation. The mice in the irradiation+IgG group and irradiation+CD25 group were intraperitoneally injected with IgG antibody and CD25 antibody every week, respectively. Six mice were killed at 4 and 8 weeks after irradiation respectively. Flow cytometry was used to detect the percentage of CD25 +Foxp3 +Tregs in the lung tissue of each group of mice to identify whether the model was established successfully. Then, Western blot was used to detect the expression of neuropilin 1 (NRP1) in the lungs of the mice in the control group and irradiation group. Immunofluorescence was used to detect the percentage of CD25 +NRP1 +Tregs. Photos were taken to observe the skin damage of each group of mice. Hematoxylin eosin staining was used to detect the pathological changes of lung tissue. The secretion of cytokines, namely, transforming growth factor-beta 1 (TGF-β1), interleukin (IL)-17A, interferon-γ (IFN-γ), IL-2, and IL-4, in the lung tissue of each group was detected by enzyme-linked immunosorbent assay. Independent sample t-test was used for comparison between the two groups. Results:The results of flow cytometry showed that the percentage of CD25 +Foxp3 +Tregs ((1.73±0.04)%, (2.13±0.15)%) in the lung tissue of mice in the simple irradiation group was significantly higher than that in the control group ((1.14±0.02)%, (1.70±0.06)%) ( t=-26.680, -4.545; P=0.000, 0.010) at 4 and 8 weeks. After the inhibition of Treg cells, the percentage of CD25 +Foxp3 +Tregs ((0.72±0.14)%, (0.27±0.02)%) in the lung tissue of mice in the irradiation+CD25 group was significantly lower than that in the irradiation group alone ( t=5.296, 37.538; both P=0.000). The result of Western blot showed that the expression of NRP1 protein in the lung tissue of mice in the irradiation group increased significantly ( t=-7.341, -9.127; both P=0.000). The results of immunofluorescence showed that the proportion of CD25 +NRP1 +Tregs in the lung tissue of mice in the irradiation group was higher than that in the control group at 4 and 8 weeks after irradiation. The proportion of CD25 +NRP1 +Tregs in the irradiation+CD25 group was lower than that in the irradiation group ( t=8.926, 14.457; P=0.001, 0.000). The skin lesions observed were severe in the simple irradiation group. The skin in the irradiated+CD25 group was almost intact at 4 weeks, and hair removal and peeling still occurred at 8 weeks. Hematoxylin eosin staining showed that relative to that in the control group, the lung tissue structure of the mice in the irradiated group was destroyed, the alveolar wall was thickened, and the extracellular matrix was increased at 4 and 8 weeks after irradiation. The lung tissue of the irradiated+CD25 group was intact and the alveolar wall was slender. As indicated by the changes in inflammatory factors, relative to that in the control group, the secretion of IL-17A and IL-4 in the lung tissue of mice increased in the simple irradiation group ( t=-8.492, -15.796; P=0.001, 0.000) at 4 weeks. After 8 weeks of irradiation, the levels of TGF-β1 and IL-17A increased significantly ( t=-11.072, -7.167; P=0.000, 0.002), and the levels of IL-2 decreased at 4 and 8 weeks. IFN-γ secretion increased at 4 weeks ( t=-27.393, P=0.000) and decreased at 8 weeks. Relative to that in the simple irradiation group, TGF-β1 and IL-17A decreased ( t=6.037, 4.524, 5.496, 4.772; all P=0.000), IFN-γ increased ( t=-7.006, -12.565; P=0.002, 0.000) at 4 and 8 weeks, and IL-2 and IL-4 decreased at 4 weeks and increased significantly at 8 weeks ( t=2.866, -9.090, 8.833, -7.191; all P=0.000) in the irradiation+CD25 group. Conclusion:The differentiation of Tregs occurs in the lung tissue of mice with radiation-induced lung injury and promotes the development of radiation-induced lung injury by secreting TGF-β1 pro-inflammatory factor while interfering with the balance of helper T cell (Th)1/Th2 type cytokines.

Radiotherapy is one of the important means of combined therapy for treating tumors. However, radioresistance is a serious issue that affects the curative effect and prognosis of radiotherapy for tumor patients. Given the complex mechanism of radioresistance in tumor cells, the specific switch molecules that can regulate radiosensitivity are not yet discovered. Circular RNA(circRNA) is a kind of closed circular RNA molecules that covalently bind the 3'-end and 5'-end by trans-splicing with high abundance, stable structure, and strong specificity. CircRNA is involved in tumorigenesis, development, invasion, and metastasis and can be used as a novel tumor molecular marker and potential therapeutic target. In addition, circRNA is differentially expressed in irradiated tumor cells and can serve as a sponge to regulate microRNA and its downstream signaling pathways that are related to tumor radioresistance. Therefore, the research on circRNA might be a promising breakthrough toward overcoming tumor radioresistance. In this study, we reviewed the progress in the research on circRNAs as novel tumor markers, as well as the research prospects regarding the application of radiotherapy.

目的:观察神经菌毛蛋白1(NRP1)基因对放射性肺纤维化(RIPF)进程的影响,并探讨其在Wnt/β-连环蛋白(β-catenin)信号通路和转化生长因子β1(TGF-β1)/Smads通路介导的上皮间质转化(EMT)发生发展过程和细胞外基质(ECM)沉积中的作用.方法:利用Cre-LoxP重组酶系统构建肺泡Ⅱ型上皮细胞(AT-Ⅱ)特异性敲除NRP1基因的转基因C57BL/6J小鼠并进行鼠尾鉴定,将160只小鼠按照射后不同时间点随机分为4周组、8周组、16周组和24周组,每组小鼠按随机数字表法分为野生型(Con)组、野生型单纯照射(IR)组、NRP1基因特异性敲除(KO-Con)组和NRP1基因特异性敲除+照射(KO+IR)组,每亚组10只.KO-Con和KO+IR组小鼠腹腔注射他莫昔芬特异性敲除AT-Ⅱ细胞NRP1基因,IR组和KO+IR组小鼠采用20 Gy全胸照射建立RIPF小鼠模型.模型构建完成后,利用HE染色法和Masson染色法验证模型是否构建成功;利用免疫组织化学(IHC)法检测小鼠肺组织中Ⅰ型胶原(ColⅠ)和α平滑肌肌动蛋白(α-SMA)的蛋白表达水平;Western blotting法检测小鼠肺组织中NRP1、β-catenin、TGF-β1和Smad2蛋白表达水平;实时荧光定量-聚合酶链反应(qRT-PCR)法检测小鼠肺组织中NRP1、ColⅠ、α-SMA、β-catenin、TGF-β1、Smad2、上皮型钙黏蛋白(E-cadherin)、神经型钙黏蛋白(N-cadherin)和波形蛋白(Vimentin)mRNA表达水平.结果:HE染色和Masson染色显示RIPF小鼠模型构建成功,IR组小鼠肺部主要为放射性肺炎病理形态表现.与Con组比较,随时间的延长,IR组小鼠肺组织中NRP1蛋白和mRNA表达水平逐渐升高(P<0.05),24周时达到最高(P<0.01).与Con组比较,随时间的延长IR组和KO+IR组小鼠肺组织中ColⅠ、α-SMA、β-catenin、TGF-β1和Smad2蛋白及mRNA表达水平逐渐升高(P<0.05或P<0.01);与IR组比较,随时间的延长,KO+IR组小鼠肺组织中ColⅠ、α-SMA、β-catenin、TGF-β1和Smad2蛋白和mRNA表达水平均明显降低(P<0.05或P<0.01),但仍高于Con组(P<0.05或P<0.01).与Con组比较,随时间的延长,IR组和KO+IR组小鼠肺组织中上皮细胞标志物E-Cadherin mRNA表达水平逐渐降低(P<0.05),间质细胞标志物N-Cadherin和Vimentin蛋白表达水平升高(P<0.05或P<0.01),但KO+IR组小鼠肺组织中E-Cadherin mRNA表达水平明显高于IR组(P<0.05或P<0.01),N-Cadherin和Vimentin mRNA表达水平均明显低于IR组(P<0.05或P<0.01).结论:NRP1基因敲除可抑制RIPF的发生发展,其机制可能与调节小鼠肺组织中Wnt/β-catenin和TGF-β1/Smads信号通路的表达进而抑制EMT进程有关.

为解决实验内容方法陈旧,制备气敏元件的性能指标无法满足实际测试要求的问题,对半导体气敏材料的制备及其气敏特性测量进行了实验研究,从而提高元件的性能,并使实验内容满足本科教学更加贴近科学研究前沿的需求.通过采用溶剂热法制备了三元金属氧化物Zn2 SnO4气敏材料并对其性能进行了系统测量,并将该实验内容应用于电子功能材料实验的开放性创新实验中.结果表明,基于Zn2 SnO4材料的气敏元件对HCHO气体表现出优异的气敏特性.通过该实践过程,使学生掌握一种合成纳米材料的新方法,了解材料表征方法,该项目的实施有利于学生提高科研素质和创新能力的培养.

为了解决半导体掺杂浓度的测试问题,需要采用简单易行的方法对半导体进行测试.在微电子技术领域,四探针技术一直是测量电阻率的常用方法.结合吉林大学在半导体器件物理与实验精品课程的建设,以训练学生对半导体物理学专业知识的理解和掌握,笔者对四探针法测试半导体掺杂浓度进行了实验研究.通过建立半无限大和无限薄层两个理论模型,对不同厚度半导体材料的电阻率测试方法进行了实验研究,并对原理进行了讨论.为了解决商用测试设备昂贵且无法满足实验教学需求的问题,笔者提出自制实验测试装置,采用钨合金的简易手动探针台,并根据实验需要自行设计了四探针测试架.实践应用表明:四探针测试系统的建立可以完成测量半导体掺杂浓度的任务,满足了半导体物理实验的教学需求,取得了较好的教学效果.

In order to demonstrate the effect of perfusion magnetic resonance (MR) and diffusion tensor magnetic resonance imaging (MRI) in evaluating glioma, arterial spin labeling (ASL) imaging is used to calculate the hemodynamic parameter cerebral blood flow. Diffusion tensor imaging (DTI) is mainly used to analyze the diffusion coefficient of water molecules in the brain, obtaining anisotropic scores, average diffusion coefficients, diffusivity parameters, etc. The separability of these parameters is studied by analyzing the distribution of single parameters, single-model multi-parameters and multi-model multi-parameters. Parameters obtained in this paper are basically consistent with those reported in the previous literature, and the statistical analysis of each parameter is also basically the same as that of predecessors.

Objective: To evaluate the efficacy and safety of combination timorazolamide (TMZ) with three-dimensional conformal radiotherapy on residual disease after treatment of glioblastoma. Methods: Fifty-eight patients with residual disease after treatment of glioblastoma were enrolled in this study from October 2013 to September 2015. The patients were randomly divided into TMZ plus radiotherapy group and control group (29 cases in each group) using the random number table. Three-dimensional conformal radiotherapy was performed in both groups. Based on the body surface area, optimal dosage of TMZ was used in TMZ plus radiotherapy group simultaneously. The short-term efficacy, long-time survival rate and adverse reactions were recorded. Results: The overall response rate in TMZ plus radiotherapy group (72.41%) was significantly higher than that in control group (37.93%, P<0.05). The median survival time in TMZ plus radiotherapy group and control group were 28.3 and 11.2 months, respectively. The two-year survival rates in TMZ plus radiotherapy group and control group were 51.72% and 13.79%, respectively. There was significant difference between two groups through Log Rank test (X-2=4.664, P=0.028). The treatments in two groups were tolerated in patients. There were less adverse reactions in both groups, and normally mild and moderate reactions (grade I-II). Conclusion: The postoperative residual disease after treatment of glioblastoma was significantly improved by TMZ combined with three-dimensional conformal radiotherapy. This treatment could prolong the survival time of patients with good safety. Moreover, this treatment increased the overall response rate and survival rate, and could be adapted in other studies in the future.

OBJECTIVE:This study aimed to evaluate the difference and consistency between single-photon emission computed tomography-computed tomography (SPECT-CT) and MRI in diagnosing osteoporotic vertebral compression fractures (OVCFs) and identifying active lesions. PATIENTS AND METHODS:All 46 patients underwent SPECT-CT and MRI examinations. The pain vertebral body and pain sites were determined using both MRI and SPECT-CT during percutaneous kyphoplasty (PKP). The differences before and after treatment were assessed using visual analog scale scores and evaluated using a paired t-test. Furthermore, the difference and conformity of SPECT-CT and MRI in diagnosing OVCFs were determined using the McNemar test and the κ-statistic, and by calculating the accuracy index of SPECT-CT diagnosis. RESULTS:Among all 46 patients, MRI showed 79 segments that fulfilled the diagnostic criteria for fresh OVCFs, whereas SPECT-CT showed 83 segments, and a total of 77 affected vertebral bodies were treated with PKP. Paired t-test evaluation showed that PKP was effective, suggesting that the affected sites were determined accurately (P<0.05). Furthermore, the κ-statistics indicated that these two methods were highly consistent (P<0.05) and the McNemar test indicated that the efficacy of these two diagnostic methods was closely correlated (P>0.05). In different stages of fractures, especially the acute phase, the consistency of SPECT-CT and MRI in the diagnosis of fresh OVCFs was high. CONCLUSION:SPECT-CT is the preferred method for imaging diagnosis when patients with suspected OVCFs have contraindications to MRI, particularly for patients with acute fractures.

Objective: To investigate and analyze survival-related factors, cognitive function, and quality of life of elderly patients after operation for glioma. Methods: Clinical and follow-up data of 156 elderly patients with glioma surgically treated in China-Japan Union Hospital of Jilin University from January 2011 to December 2014 were retrospectively analyzed. The effects of the patient's gender, age, preoperative Karnofsky Performance Status (KPS) score, tumor diameter, pathological grading, postoperative radiotherapy, postoperative chemotherapy, degree of surgical resection, and expression of tumor molecular markers on survival time were analyzed by Kaplan-Meier method, and changes in cognitive function (Mini-mental State Examination (MMSE) score) and quality of life (KPS score) of patients before operation and 1 month after operation were compared. Results: Total MMSE score and scores of dimension of cognitive function of elderly patients with glioma 1 month after operation were significantly increased compared with those before operation (all P<0.05), and the KPS score of elderly patients with glioma 1 month after operation was significantly higher than that before operation (P<0.05). Univariate analyses revealed that age, tumor diameter, preoperative KPS score, preoperative pathological grading, postoperative radiotherapy/chemotherapy, degree of surgical resection, and matrix metalloprotein-9 expression had significant influences on the survival prognosis of patients (all P<0.05). According to results of COX multivariate regression analyses, preoperative pathological grading, tumor diameter, preoperative KPS score, and postoperative radiotherapy/chemotherapy were independent risk factors affecting the postoperative prognosis of elderly patients with glioma (all P<0.05). Conclusion: Cognitive function and quality of life of elderly patients can be effectively improved via glioma operation. Preoperative pathological grading, tumor diameter, preoperative KPS score, and postoperative radiotherapy/chemotherapy are independent risk factors affecting the postoperative prognosis of patients.

本文先介绍了半导体平面工艺的发展史，及其在重要的现实意义，然后简单叙述了本实验教学中心开设的《半导体器件平面工艺实验》的课程内容设置，对实验课课堂教学中的理论和实际教学方法进行了探讨，提出课前集中讲解和实验后答疑分析讲解相结合的实验教学方法，并引导学生以科技论文形式完成专业实验课实验报告的创新教学思路。

口腔种植技术是在牙槽突内植入一人工装置并与颌骨结合,用以支撑和固位修复体,完成对缺牙的修复[1],其具有一定的复杂性。因此,如何确保口腔种植体修复成功是至关重要的。学者们主要从种植体植入后的动度、骨吸收量、骨密度的变化等方面对种植体成功与否进行评定[2]。1986年Albrektsson等学者确立种植体成功标准为:单个种植体无松动;X线检查种植体周围无明显的阴影透射区;种植体

传统上利用LiCl制作的湿度传感器只能在一段湿度的范围内进行湿度的测量,并且由于LiCl易水解的性质,经过一段时间的使用后,LiCl容易流失而使元件失效。实验中将LiCl材料担载到SBA-15分子筛中来改善材料的湿敏特性,并对材料分别进行了IR和SEM表征分析。利用该系列材料制作并获得了全湿度范围内特性良好的电阻型湿敏元件。通过不同比例的LiCl的掺杂,选择出掺杂量为15%wt LiCl的样品最适宜制备湿敏元件。实验测试得到了元件在不同湿度下的复阻抗谱图,通过对复阻抗谱图以及材料结构的研究,分析了基于该材料的湿敏元件在不同相对湿度下的导电机理。

The mesoporous silica SAB - 15 material was synthesized by template method.Metal salt were doped in order to improve the humidity sensing properties of the material.The microstructure and morphology of materials were characterized by scanning electron microscope(SEM) and XRD.Humidity sensing properties of pure SBA - 15 and metal salt doped SBA - 15 were studied from 11%RH to 95%RH.The results show that appropriate metal salt doped could improve the humidity sensing properties of pure SBA - 15 clearly.The response and recovery time of metal salt doped materials are quite quickly,the response time are all less than 60 s and recovery time are all less than 180 s.All these parameters have achieved the practice application standard.