基于工业CT断层图像的三维可视化

工业CT图像三维可视化能够对工业构件提供真实、直观的反映。体绘制技术可以显示工业CT三维数据的整体特征和内部细节信息。根据光线投射算法的特点，采用对原始数据场进行最大熵原则的预处理的方法，加快了绘制速度，在一定程度上改进了光线投射算法，取得了较好的显示效果。     

构建巯基-AIBN表面引发体系制备接枝微粒PGMA-SiO2及其功能性转变的研究

先使用偶联剂γ-巯丙基三甲氧基硅烷(MPMS) 对微米级硅胶微粒进行了表面改性,然后使改性微粒表面的巯基与溶液中的偶氮二异丁腈(AIBN)构成巯基-AIBN引发体系,引发油溶性单体甲基丙烯酸缩水甘油酯(GMA)在硅胶微粒表面发生接枝聚合,制得了高接枝度(23 g/100 g)的接枝微粒PGMA SiO2。对影响GMA接枝聚合的主要因素进行了考察,对表面引发接枝聚合的机理进行了研究。以对氨基苯磺酸钠为试剂,通过环氧基团的开环反应,对PGMA-SiO2接枝微粒进行了功能化改性,将阴离子基团苯磺酸钠(BSNa)键合于接枝大分子PGMA侧链,制得功能接枝微粒BSNa PGMA SiO2,并初步研究了其功能性。 研究表明,受溶液中的AIBN分解反应的诱导,改性硅胶微粒表面的巯基会发生氢原子转移,在硅胶微粒表面产生硫自由基,使GMA可在硅胶微粒表面有效地发生接枝聚合。接枝聚合适宜的温度为55 ℃,适宜的AIBN用量为单体质量的0.8%。功能接枝微粒BSNa PGMA-SiO2表面携带有高密度的负电荷,对苦参碱和金雀花碱等生物碱分子具有强吸附作用。     

基于独立成分分析的精神分裂症患者动态脑功能网络分析新方法

目的 提出一种新的基于独立成分分析法进行动态脑功能网络分析的方法,并应用该方法探讨精神分裂症患者在动态全脑功能网络上的变异。方法 首先基于滑动时间窗方法计算正常被试和精神分裂症患者的动态全脑功能网络,然后使用组信息指导独立成分分析方法,提取每个被试的动态全脑功能网络的功能连接状态及相应的时间波动,比较正常被试和精神分裂症患者在功能连接状态上的差异。结果 两组的最重要功能连接状态的模式有相似性。正常被试在额叶、顶叶相关区域较精神分裂症患者具有更强的正功能连接;在小脑相关区域精神分裂症患者呈现出更多的正功能连接,而正常被试呈现出更多的负功能连接。结论 组信息指导独立成分分析方法可有效提取动态脑功能网络的功能连接状态,可揭示精神分裂症患者在动态脑功能网络的变异。     

一种基于笔形束核的快速剂量计算方法

针对传统笔形束核剂量算法计算过程复杂、速度较慢的问题,提出一种基于笔形束核的快速剂量计算方法。该方法在球壳坐标系下,利用射束与不同球壳层碰撞后轴线与体素相交情况的相似性,通过对每条射束只计算初始球壳层碰撞点处轴线与体素的相交情况,并将初始球壳层深度与其它球壳层深度的比值作为校正因子得到其他层碰撞点处轴线与体素的相交情况。避免射线追踪法的重复使用,在不影响算法精度的情况下节省大量时间。实验结果表明:在不同射野大小［（3×3）、（5×5）、（10×10） cm2］的水模体中计算深度剂量分布,两种算法的计算精度基本一致,改进算法的计算速度提升约2.7倍。同时当射野面积为（10×10） cm2时,在肺阻块模体和骨阻块模体不同深度的剖面剂量计算中,改进算法与传统算法的计算精度也基本一致,但计算速度提升约2.6倍。     

运动与c-fos原癌基因的研究进展

c-fos原癌基因属于即刻早期基因（IEG），近几年来，随着对其生物学功能认识的逐渐深入，人们开始从不同的角度探讨影响c-fos原癌基因表达的因素。笔者综述了近年来国内外有关运动与c-fos原癌基因的相关研究现状，并对以后的研究提出一些建议。     

Study of Automatic Enhancement for Chest Radiograph

Because of the large difference of the densities in the lung and other structures, the chest x-ray image behaves as a wide-range intensity distribution, which brings on a bit of difficulty to investigate the focus. In the paper, according to the intensity properties of the chest radiograph, the chest radiographic image is divided into three subregions, and a piecewise linear transformation model is established. An approach of automatic enhancement is presented, based on the gray-level normalization. The average enhanced ratios of three subregions of the normal and severe acute respiratory syndrome image are increased by 10.70% and 25.55%, respectively. The technique is proved to be effective through the evaluation of the improved images.     

Evaluation of polyethylene glycol precipitation as screening test for macroprolactinemia using Architect immunoanalyser

We performed the polyethylene glycol (PEG) precipitation test to determine the prevalence of macroprolactinemia in 172 hyperprolactinemic subjects with prolactin (PRL) levels > 700 mIU/l. PRL was measured by Architect i2000 (Abbott Diagnostics) both in serum and in supernatant obtained after PEG. We used the PRL recovery percentage (R%) as interpretative criterion of PEG test and we estimated a prevalence of macroprolactinemia of 21.5% (R% ≤ 40%), whereas 74.4% of subjects showed a true hyperprolactinemia (R% ≥ 60%). In true hyperprolactinemic subjects PRL levels obtained before and after PEG showed a good correlation (Pearson coefficient, R = 0.995); in macroprolactinemic individuals no correlation was found. The PEG test was also performed in 50 normoprolactinemic subjects and a new PRL reference interval was obtained: 64–453 mIU/l. In this case the macroprolactinemic subjects (hyperprolactinemic presenting a normal PRL value after PEG) were 20.3% whereas 79.7% showed still elevated PRL levels. In 35 females we were also able to evaluate the symptoms and the pituitary imaging findings: no significant differences between macroprolactinemic (N = 11) and true hyperprolactinemic (N = 24) subjects were found. In conclusion, the PEG test appears to be simple, reproducible and absolutely necessary for diagnostics of hyperprolactinemia.     

Influence of Mo Segregation at Grain Boundaries on the High Temperature Creep Behavior of Ni-Mo Alloys: An Atomistic Study

Based on molecular dynamics simulations, the creep behaviors of nanocrystalline Ni before and after the segregation of Mo atoms at grain boundaries are comparatively investigated with the influences of external stress, grain size, temperature, and the concentration of Mo atoms taken into consideration. The results show that the creep strain rate of nanocrystalline Ni decreases significantly after the segregation of Mo atoms at grain boundaries due to the increase of the activation energy. The creep mechanisms corresponding to low, medium, and high stress states are respectively diffusion, grain boundary slip and dislocation activities based on the analysis of stress exponent and grain size exponent for both pure Ni and segregated Ni-Mo samples. Importantly, the influence of external stress and grain size on the creep strain rate of segregated Ni-Mo samples agrees well with the classical Bird-Dorn-Mukherjee model. The results also show that segregation has little effect on the creep process dominated by lattice diffusion. However, it can effectively reduce the strain rate of the creep deformation dominated by grain boundary behaviors and dislocation activities, where the creep rate decreases when increasing the concentration of Mo atoms at grain boundaries within a certain range.     

武术功力运动对腕骨形态结构影响的定量CT研究

目的：研究武术功力运动（单掌断砖）对腕骨形态结构的影响。方法：选取功力运动员（功力组）8人、非运动员（对照组）6人,均为20~30岁男性。经64层螺旋CT扫描腕骨并进行三维重建,测量各腕骨体积、相对体积、骨密度。结果：功力组小多角骨左、右手体积均大于对照组（P<0.05）,其它腕骨两组间比较无显著性差异（P>0.05）,功力组左、右手间各腕骨体积也无显著性差异（P>0.05）;功力组各腕骨相对体积与对照组比较无显著性差异（P>0.05）;功力组右手头状骨、钩骨CT值及左手头状骨CT值明显大于对照组（P<0.05）,其它腕骨两组间无显著性差异（P>0.05）,功力组左、右手间各腕骨CT值比较也无明显差异性（P>0.05）。结论：武术功力运动（单掌断砖）所产生的应力对各腕骨体积影响较小,但可使受力部位某些腕骨的骨密度增高。