Assessment of alternated cooling and heating treatment by US combined CEUS in the VX2 rabbit liver tumor model

Inoperable liver tumors are often treated by thermal ablation that destroys the tumor in situ and spares the adjacent hepatic tissue.Thermal–physical treatment has many advantages,but treatment by freezing or heating alone has some limitations.By taking the advantages and disadvantages of cryosurgery and thermotherapy into consideration,a new thermal technique that combines cryosurgery and radio frequency ablation has been proposed,thereby overcoming the disadvantages of each treatment strategy and improving therapeutic outcomes.This new approach remains to be systematically studied in the liver;therefore,this study was performed to estimate survival after alternated cooling and heating ablation therapy in a VX2 rabbit liver tumor model.Sixteen days after VX2 carcinoma implantation into the rabbit liver,tumors were treated with alternated cooling and heating ablation therapy.Rabbits were monitored for 6 months after treatment and assessed with ultrasound(US)and computed tomography at 1,7,14,and 30 days posttreatment.Untreated tumor-bearing animals served as the control group.Our results show that alternate freezing and heating ablation therapy resulted in a good recovery of VX2 rabbits.Compared with the control group,treated rabbits lived significantly longer(P\0.05),with 70%of treated animals surviving to 196 days posttreatment without metastasis or recurrence,while none of the controls did so.There was no local recurrence in the treatment group.All rabbits in the control group developed metastasis,while metastasis was only observed in 30% of treated rabbits.These results suggest that alternate cooling and heating ablation therapy can prolong the survival time of rabbits with VX2 liver tumors and is an effective method for tumor therapy.Furthermore,we also showed in this model that contrast enhanced US is a valid follow-up approach to assess treatment effectiveness.     

超声波辅助提取杜仲皮中的杜仲胶和杜仲黄酮

对超声波辅助提取杜仲皮中的杜仲胶和杜仲黄酮进行了研究.通过筛分和风选方式分选物料,分别提取胶和黄酮,使杜仲有效成分得到较大利用.研究超声频率、功率、提取时间和物料质量浓度对杜仲胶提取量的影响.结果表明,频率40 kHz时提取效果较好,提取量随功率、时间的增加和物料质量浓度的减少而提高.空气压缩机风速为4.9 m/s时,物料分选效果和1 mm筛选效果近似.通过前期分选,杜仲胶和杜仲黄酮没有损失.将杜仲粉碎后,粉末中杜仲胶的含量远小于絮状物中杜仲胶含量,并且先提取杜仲胶再提黄酮,更有利于杜仲胶和杜仲黄酮的利用.     

An efficient non-iterative algorithm to estimate the apparent diffusion coefficient of water molecules in the magnetic resonance diffusion imaging experiments

Many studies have shown that the magnetic resonance signal decay with an extend range of diffusion weighting(b-factor)is a bi-exponential attenuation in the diffusion-weighted magnetic resonance imaging experiments in vivo.Based on this feature and the two-compartmental model,we propose a twice-linear-fitting(TLF)algorithm to estimate the apparent diffusion coefficient(ADC)of the water molecules instead of the commonly used iterative Levenberg–Marquardt(LM)method.The TLF algorithm consists of two liner fitting steps to estimate the fast and the slow apparent diffusion coefficients and their sizes,respectively.It is unnecessary to guess the initial values in the whole fitting process.The time consumption of the TLF algorithm is much less than that of the iterative LM method.Moreover,the TLF algorithm may avoid the extraneous solutions,which often deteriorates the results of the LM method.Compared with the iterative fitting method,the TLF algorithm is a reliable and timeefficient approach to estimate the ADC of water molecules in vivo in magnetic resonance diffusion-weighted imaging experiments.     

超声雾化液体除湿系统对室内空气品质的影响

研究了超声雾化液体除湿空调系统对室内空气品质的影响,得到室内空气中氯化锂质量浓度的安全阈值为70μg/m~3.通过实验分析了入口溶液中氯化锂的质量分数(w_i)、除雾器孔隙率等对空气带液量的影响.当w_i由31.5%上升至38.8%时,空气带液量也随之上升,最高为26.93μg/m~3.除雾器的孔隙率显著影响空气带液量,应使用孔隙率低于93.5%的丝网除雾器.在最不利工况下,该系统空气带液量未超过安全阈值,表明对室内空气品质没有影响.研究成果对超声雾化液体除湿系统的推广有一定指导意义.     

电子贴附解离过程中的物理和化学

电子贴附解离是低能量电子与分子碰撞的重要过程,涉及电子与靶分子的相互作用、电子-分子共振态、瞬态负离子分子的解离动力学等基础物理和化学问题.本文对近年来该领域的重要进展,特别是基于负离子速度成像方法的实验研究,进行了阶段性总结,并对其未来发展方向和潜在应用进行了讨论.     

基于图像特征改进的正交匹配追踪算法

将压缩传感理论应用于成像是光场成像理论的热门研究方向,由此可以设计出更简单、便宜、小巧的光学系统.正交匹配追踪算法是压缩传感理论的重要重构算法,它在重建图像时隐含着整幅图像权重相同的思想,没有体现出图像的固有特征,例如行列突变的剧烈程度,以及经过快速傅里叶变换基、离散余弦变换基、离散小波变换基作用得到的小稀疏系数代表图像的细节、大稀疏系数代表图像的轮廓的特点.使用上述3种变换基作用图像时,可以针对正交匹配追踪算法的固有缺点,提出合理选择逐行或者逐列重构图像和使用自适应迭代次数重构图像两种改进方法.仿真结果表明,改进算法明显提高了图像的质量,能够得到更好的图像视觉效果.     

一种基于分子内环化反应的荧光触发型探针在硫化氢检测中的应用

硫化氢是一种重要的气体信号分子,参与调节多种生物过程.对生物样品内的硫化氢进行选择性成像是理解其生理功能的一个重要手段.本研究报道一种具有新型反应机理的无荧光探针(DNP-CMP)在硫化氢检测中的应用.通过硫化氢介导硫解反应可脱除DNP-CMP的二硝基苯醚保护基,而暴露的羟基引发探针的分子内环化反应,生成荧光分子香豆素,从而实现硫化氢的低背景检测.DNP-CMP检测硫化氢的专一性高,可藉以实现细胞内硫化氢的荧光成像.     

糖复合物的生物应用

糖类化合物是一类很重要的生物大分子,它在细胞膜表面通过形成各种复合物参与许多重要的生理活动。主要讨论了近几年糖类复合物在药物靶向传递及肿瘤成像/检测等方面的研究进展,综述了叶酸、寡糖等作为靶向基团的药物靶向传递体系,同时探讨了各种糖类复合物在细胞成像及生物检测方面的应用,指出了未来糖化学的发展前景。     

基于反射光谱成像的相似异物检测新方法

针对现有方法进行相似异物检测时成本高、效果差等问题,提出一种基于优选波长反射光谱成像技术的相似异物检测新方法.该方法利用建立的波长优选函数,分析了近紫外一可见一近红外离散波段中异物与背景灰度差随波长变化规律,筛选了区分多个异物与背景的最佳光照波长,以此构建反射光谱成像检测系统.根据最佳波长反射成像系统来获取相似异物特征,同时,根据二值化自适应阈值来对异物提取图像进行处理.以棉花中的白色丝状异物为对象对该方法进行实验,结果表明,在反射光照系数为0.74时,该方法对相似异物的检测率达到94％.     

新型骨显像剂99mTc-EDP的合成与研究

以亚磷酸二乙酯为原料,经多步反应合成了亚乙烯基二膦酸(EDP)配体.通过1HNMR测定进行了结构确认;经99mTc标记后,标记率高于95%.体外稳定性测定表明,6h后放化纯度仍保持在90%以上.小鼠体内分布实验表明,99mTc-EDP与99mTc-MDP(99mTc-亚甲基二膦酸)均具有较强的亲骨性能,99mTc-EDP骨摄取优于99mTc-MDP,并且随着时间的增加,骨与非靶器官摄取的比值都在增加,远远高于99mTc-MDP.进行了狗SPECT全身骨显像实验,2h后获得清晰的图像.