多次上腹部手术患者腹腔镜胆囊切除术的可行性研究

目的：探讨多次(≥2次)上腹部手术患者腹腔镜胆囊切除术(LC)的可行性和手术特点。方法：连续观察21例有多次上腹部手术史的LC患者，对治疗结果进行回顾性分析。结果：LC成功13例，成功率为61．9％。2次上腹手术后患者LC成功率为66．7％，3次者为33．3％。8例中转剖腹手术，中转率为38．1％，平均手术时间为72．1min，明显高于同期无上腹部手术史的患者。LC完成及中转剖腹手术患者均无相关手术并发症发生。结论：多次上腹手术史不应成为LC的禁忌证，但其手术难度加大，中转剖腹率增高，手术时间延长，对手术医师的技术要求较高。     

CT and MR Image Fusion Scheme in Nonsubsampled Contourlet Transform Domain

Fusion of CT and MR images allows simultaneous visualization of details of bony anatomy provided by CT image and details of soft tissue anatomy provided by MR image. This helps the radiologist for the precise diagnosis of disease and for more effective interventional treatment procedures. This paper aims at designing an effective CT and MR image fusion method. In the proposed method, first source images are decomposed by using nonsubsampled contourlet transform (NSCT) which is a shift-invariant, multiresolution and multidirection image decomposition transform. Maximum entropy of square of the coefficients with in a local window is used for low-frequency sub-band coefficient selection. Maximum weighted sum-modified Laplacian is used for high-frequency sub-bands coefficient selection. Finally fused image is obtained through inverse NSCT. CT and MR images of different cases have been used to test the proposed method and results are compared with those of the other conventional image fusion methods. Both visual analysis and quantitative evaluation of experimental results shows the superiority of proposed method as compared to other methods.     

基于小波变换和Adaboost算法的心脏骤停预测模型研究

为了预测心脏骤停,应用小波变换和Adaboost算法建立心脏骤停预测模型。首先用小波变换方法对正常窦性心律心电数据和有心脏骤停症状患者的心电数据进行分析、提取特征值,再用Adaboost算法对两种数据进行分类来预测心脏骤停的发生。实验验证,本模型分类预测效果较好,在心脏骤停发生前5min,其预测精度高达97.56%,为心脏骤停的预测提供了一种有参考价值的方法。     

Photo-polymerisation variables influence the structure and subsequent thermal response of dental resin matrices

ObjectiveThe structure of the polymer phase of dental resin-based-composites is highly sensitive to photo-polymerisation variables. The objective of this study was to understand how different polymer structures, generated with different photo-polymerisation protocols, respond to thermal perturbation.MethodsExperimental resins were prepared from a series of Bis-GMA/TEGDMA blends (40/60, 50/50 and 60/40 wt.%), with either Camphorquinone/DMAEMA or Lucirin TPO as the photo-initiator system. Resins were photo-polymerised, in a disc geometry, at either relatively ‘high’ (3000 mW cm⁻² for 6 s) or ‘low’ (300 mW cm⁻² for 60 s) irradiances ensuring matched radiant exposures (18 J cm⁻²). Specimens were heated, from 20−160 °C at a rate of 5 °C min⁻¹, whilst simultaneous synchrotron X-ray scattering measurements were taken at 5 °C increments to determine changes in polymer chain segment extension and medium-range order as a function of temperature. For each unique resin composition (n = 3), differential scanning calorimetry was used to measure glass transition temperatures using the same heating protocol. A paired t-test was used to determine significant differences in the glass transition temperature between irradiance protocols and photo-initiator chemistry at ɑ = 0.05.ResultsResins pre-polymerised through the use of TPO and or high irradiances demonstrated a reduced rate of chain extension indicative of lower thermal expansion and a larger decrease in relative order when heated below the glass transition temperature. Above the transition temperature, differences in the rate of chain extension were negligible, but slower converted systems showed greater relative order. There was no significant difference in the glass transition temperature between different photo-initiator systems or irradiance protocols.SignificanceThe evolution of chain extension and medium-range order during heating is dependent on the initial polymer structure which is influenced by photo-polymerisation variables. Less ordered systems, generated at faster rates of reactive group conversion displayed reduced chain extension below the glass transition temperature and maintained lower order throughout heating.     

自身化学离子化/傅里叶变换质谱法研究复杂有机化合物的分子量

自身化学离子化/傅里叶变换质谱(SCI/FTMS)技术研究能挥发的复杂有机化合物,可同时获取准分子和特征碎片的信息。本文研究并测定了一系列这类化合物。     

自身化学离子化/傅里叶变换质谱法研究复杂有机化合物的分子量

自身化学离子化/傅里叶变换质谱(SCI/FTMS)技术研究能挥发的复杂有机化合物,可同时获取准分子和特征碎片的信息。本文研究并测定了一系列这类化合物。     

B-样条子波在图像边缘检测中的应用

由于经典的边缘提取算子的处理结果不是十分令人满意,本文采用基于微分算子的思想以B-样条子波为处理函数的边缘提取算法。该算法充分的利用了B-样条函数在边缘拟合上的优势以及小波方法的多尺度优势,算法的处理结果令人满意。     

放射性核素32P治疗真性红细胞增多症的探讨

目的 采用放射性核素＾３２Ｐ治疗真性红细胞增多症（ＰＶ）的疗效、疗程、剂量及生存期等问题的探讨，方法 １３例ＰＶ患者进行＾３２Ｐ口服或静脉注射治疗，治疗后定期随访，确定有复发者给予下一疗程的治疗。随访时间１～１９年。结果 １３例ＰＶ病人的症状体征均有不同程度的改变，７例缓解（５３．８％），６例好转（４６％），总有效率（１００％）。生存期延长，平均１３．８年。结论 ＾３２Ｐ治疗ＰＶ疗效好，而且简便、     

Detection of abnormal proliferation in histologically ‘normal’ colonic biopsies using FTIR‐microspectroscopy

Background: Abnormal crypt proliferation and development in the colon has been associated with premalignant stages of colon cancer. Conventionally, molecular markers are used to detect abnormal crypt proliferation. Methods: In the present work, feasibility studies of FTIR‐MSP to distinguish between normal and abnormal crypts from colon biopsies that show normal histopathological features have been undertaken. Results: The results indicate that abnormal crypts show deviations in the pattern of absorbance in the Mid IR region along the crypt height when compared with the normal crypts. The crypts could be empirically classified into three groups such as crypts having a normal absorbance pattern for all biochemical components, crypts with abnormal absorbance pattern for some biochemical components and crypts with completely abnormal absorbance pattern along the height for all or most biochemical components studied by FTIR. The utilization of FTIR‐MSP is proposed for diagnosis of abnormal metabolism at the molecular level of histologically completely normal‐looking crypts, especially from those biopsies that are taken from sites far away from cancer. Conclusions: This method could give rise to a reduction in false‐negative results during examination of biopsies using the conventional histopathological methods. The present method may be complementary to existing methods for precise demarcation of the zone of colostomy prior to colon cancer surgery.