基于级联卷积神经网络的荧光免疫层析图像峰值点定位方法研究

针对目前荧光免疫层析定量图像峰值点定位易受多种因素影响,导致物质定量准确度低的问题,提出了一种融合目标检测的级联卷积神经网络(CNN)算法。第一层级联算法首先使用经改进的AlexNet算法对荧光免疫层析定量图像中包含质控(C)峰和检测(T)峰的区域进行检测和提取。之后将提取到的图像区域送入第二层级联卷积神经网络中,对C峰和T峰的位置进行快速定位。随后将定位结果输入到第三层级联卷积神经网络中,对上一层输出的C峰和T峰的定位结果进行精准微调。最后输出C峰和T峰的准确定位信息。实验结果表明,提出的级联卷积神经网络算法,对荧光免疫层析图像峰值点的平均定位准确度达到了96%以上,提高了峰值点的定位准确度。     

三维荧光光谱用于成都沙河溶解性有机物来源的研究

采用三维荧光指纹光谱技术对成都沙河的溶解性有机物（DOM）进行采样监测。结果表明,沙河水体中共检测到5个明显的荧光峰,分别为高、低激发波长类色氨酸荧光峰、类酪氨酸荧光峰和2个紫外腐殖质荧光峰,荧光峰T1（Ex/Em225/335nm）,A1（Ex/Em225/415nm）和A2（Ex/Em250/410nm）出现在整个调查河流中;荧光峰T2（Ex/Em275/300nm）出现在大部分河段,在下游其强度明显增强,高激发波长类色氨酸荧光峰T1’（Ex/Em275/335nm）只出现在下游水样中。在中下游的部分河段出现了很强的T1,T1’T2,A1,A2荧光峰,某些河段污水偷排现象严重。     

荧光定量PCR技术及其检测乳腺肿瘤同源异型盒基因的应用

荧光定量PCR技术是以荧光传递为基础多色荧光检测的核酸定量技术。能准确敏感地测定模板浓度及检测基因变异等,该技术在PCR反应体系中引入荧光标记探针,具有高灵敏性,高特异性等特点并极大地克服原有PCR技术存在的不足如交叉污染等问题。本文概述目前几种荧光定量PCR技术的原理和特点以及我们应用该技术检测乳腺肿瘤同源异型盒基因BP1的工作。     

IGF2BP2、CDKAL1基因多态性及基因-环境交互作用与2型糖尿病的关联研究

目的 :研究IGF2BP2和CDKAL1基因多态性与2型糖尿病(type 2 diabetes mellitus,T2DM)的关联,并探讨基因-环境之间的交互作用。方法 :采用病例对照研究方法,在河北省唐山市冀东油田医院体检人群中选取461例T2DM患者和434例对照,采用基质辅助激光解析-飞行时间质谱分析技术检测研究对象基因型,运用多因子降维法(multifactor dimensionality reduction,MDR)分析基因-环境交互作用。结果 :Logistic回归分析结果显示,IGF2BP2基因rs4402960位点TT基因型个体患T2DM的风险是TG/GG基因型个体的1.86倍(OR=1.86,95%CI:1.01~3.44,P=0.04),rs1470579位点CC基因型个体患T2DM的风险是CA/AA基因型个体的1.91倍(OR=1.91,95%CI:1.05~3.46,P=0.03)。吸烟者患T2DM的风险是不吸烟者的1.31倍(OR=1.31,95%CI:1.08~1.59,P=0.006)。MDR分析结果显示,rs1470579-吸烟模型的验证样本准确度(0.5862)和交叉验证一致性(10/10)均最高。CDKAL1基因各位点与环境因素均未见交互作用(P>0.05)。结论 :在本次调查的人群中,IGF2BP2基因多态性与T2DM存在关联,IGF2BP2基因rs1470579位点与吸烟因素对T2DM发病存在交互作用。     

荧光标记DNA分子量内标的设计与制备

目的:设计并制备65bp-500bp范围的荧光标记DNA分子量内标。方法:p MD18-T Vector连接任意一段割胶回收的DNA片段,克隆后提取重组质粒经双酶切后作为模板,在其上游设计一条固定引物并用荧光标记,在其下游设计一系列引物,经PCR扩增后在ABI 3100遗传分析仪上检测。结果:扩增产物DNA片段大小分别为65bp、105bp、149bp、200bp、241bp、269bp、311bp、345bp、400bp、450bp、500bp,与预期片段大小一致。结论:11个片段经混合调平后,峰型良好,出峰位置均匀,可用于毛细管电泳中DNA片段大小的确定。     

基于二维荧光相关谱的多环芳烃重叠峰解析

以激发波长为外扰,基于二维荧光相关谱技术对蒽芘混合溶液中重叠的荧光峰进行有效解析。采集了蒽、芘单组份无水乙醇溶液的激发谱,选择了蒽和芘荧光强度单调变化的5个激发波长:270nm、320nm、325nm、330nm和340nm。在此基础上,采集浓度为5×10-5g/L蒽芘无水乙醇混合溶液在5个激波长下的荧光谱,并以选择的激发波长为外扰,构建同步和异步二维荧光相关谱。结果表明:在同步谱上出现5个较强的自相关峰,位置分别在369nm、379nm、391nm、400nm和424nm处;依据未被覆盖的蒽在424nm的处荧光与各波长处荧光交叉峰的正负,指出379nm和400nm处的荧光峰来自混合溶液中的蒽,而369nm和391nm处的荧光峰来自混合溶液中的芘。同时,又根据异步二维荧光相关谱交叉峰的有无,进一步确认和验证了混合溶液中各荧光峰的来源。     

基于微流控荧光定量PCR的MRSA快速检测技术研究

针对耐甲氧西林金黄色葡萄球菌(MRSA)检测的问题,发展一种基于微流控荧光定量PCR的致病菌快速检测新技术。采用光刻法制作了微流控PCR芯片,研制了集成高性能温度控制模块和高灵敏度荧光检测模块的微流控荧光定量PCR分析系统。通过检测特异性基因femA和mecA对MRSA进行快速鉴别。实验结果表明,使用微流控PCR芯片可以成功实现MRSA特异性基因的快速检测,相对传统的管式PCR,芯片使用6μL试剂在56 min完成了MRSA特异基因的检测,不仅节约了反应试剂,而且极大提高了检测速度。该技术可扩展到其他致病菌的检测,具有良好的应用前景。     

利用X荧光能谱仪快速测定合金钢中钛元素

在合金钢能量色散X射线荧光光谱的研究基础上,使用国产的XRF-6型X射线荧光能谱仪对合金钢中钛元素进行了分析技术研究。钛元素的Kα特征射线能量值为4.51keV,与特征能量值为4.66keV的FeKα逃逸峰叠加重合,严重干扰钛元素的测定。研究了铁元素逃逸峰干扰的快速扣除方法,得到FeKα峰比例扣除、FeKα逃逸峰高能侧对称扣除法和TiKα峰低能侧对称积分法等快捷处理方法。工作曲线的制作和实际样品测定结果证明几种快速分析方法是可靠准确的。     

土壤粒径大小对蒽荧光特性的影响及校正

为了准确检测土壤中的多环芳烃,以土壤中典型多环芳烃污染物蒽为检测对象,研究了土壤粒径大小对其荧光特性的影响,并提出了一种校正土壤粒径大小对多环芳烃标准曲线影响的方法。研究了蒽在土壤中的荧光特性,指出蒽在421nm、442nm和470nm处出现较强的荧光峰。接着,制备7种不同粒径大小的蒽土壤样品,并以土壤粒径大小为外扰,构建了同步和异步二维相关荧光谱,研究了蒽荧光强度和304nm处瑞利散射光强随土壤粒径大小的变化。结果显示,随着土壤粒径增大,蒽荧光强度和304nm处瑞利散射光强度都有增强。最后,分别建立了80目和160目土壤粒径下定量分析土壤蒽浓度的标准曲线,并通过304nm处瑞利散射光对蒽荧光进行校正。结果表明:该方法有效降低了土壤粒径大小对蒽标准曲线的影响。     

实时荧光定量PCR技术在动物遗传育种中的应用

聚合酶链式反应技术(polymerase chain reaction简称PCR)是一项体外基因快速扩增技术.该技术的建立,使定性检测的技术得到改善,达到检测单个靶细胞的水平,以其简便易行、灵敏度高等优点被广泛应用于分子生物学及医学等领域.但其易污染、假阳性及定量不准确等问题也日益突出.而荧光定量PCR技术(FQ-PCR)的出现解决了以上难题,实现了从定性到定量的飞跃.此方法特异性强和可靠性更强,能实现多重反应,且采用完全闭管检测,不需要PCR后处理,有效解决PCR污染问题以及EB对试验人员的伤害;再配以相应的荧光PCR仪,使整个PCR过程实现自动化,具有耗时短,操作方便等特点,因而广泛运用于各个领域.     

Two polymorphisms in methylenetetrahydrofolate reductase gene (C677T and A1298C) frequently associated with recurrent spontaneous abortion show no association in Saudi women

Methylenetetrahydrofolate reductase (MTHFR) deficiency is the most common genetic cause of hyperhomocysteinemia, which has been implicated in the etiology of recurrent spontaneous abortion (RSA). This study was designed to investigate the association between two single nucleotide polymorphisms (SNP) (rs1801133 [C677T] and rs1801131 [A1298C]) in the MTHFR gene and RSA, in Saudis. These two SNPs were selected as these polymorphisms have a different effect on the activity and stability of the enzyme, and significantly diverse effects have been reported in relation to the association with RSA. Ethical approval was acquired from the IRB at King Saud University (KKUH), Saudi Arabia, and written informed consent was obtained from each participant. The study group comprised of 100 Saudi women with unexplained RSA and 100 age-matched controls, both attending KKUH for a routine checkup. Blood was drawn in EDTA tubes, and DNA was extracted. Genotyping was conducted using TaqMan SNP genotyping assay kits. The frequency of the T allele of C677T was 0.165 in patients and 0.17 in controls. Genotype frequencies for CC, CT and TT genotypes were 70%, 27% and 3%, respectively in RSA, and 71%, 24% and 5%, respectively, in the controls (p > 0.05). For the A1298C polymorphism, the C allele frequencies were 0.345 in patients and 0.28 in controls, while genotype frequencies for AA, AC and CC genotypes were 44%, 43%, and 13%, respectively, in patients, and 54%, 36%, and 10%, respectively, in controls (p > 0.05). The frequency of CC genotype and C allele of A1298C were higher in the patients with RSA, but not significantly, while C677T genotypes and allele frequencies did not differ between patients and controls. The results suggested that MTHFR gene polymorphisms are population-specific and may not associate with RSA in Saudi women.     

High resolution melting curve analysis with MATLAB-based program

High resolution melting curve analysis (HRM) is an emerging new method for interrogating and characterizing DNA samples. It has been used as a powerful tool for gene mutation and single-nucleotide polymorphism (SNP) detection with high throughput and low cost. Commercially available HRM analysis systems are mostly proprietary and expensive. It lacks the flexibility for the end users and researchers to incorporate new analysis algorithms into the existing system. This paper presents the development of a MATLAB-based open software program for high resolution melting curve analysis. Key analysis functions, such as to obtain the first derivative curve using Savitzky–Golay filter, to identify the melt region, subtraction of background fluorescence and curve normalization, are introduced, followed by case studies of HRM analysis using the developed software program.     

基于分辨率增强算法的质谱重叠峰分峰方法

在质谱数据分析中,重叠峰分峰是一个重要的预处理步骤。本文建立了一种基于分辨率增强算法的质谱重叠峰分峰方法。首先,采用对信号及其负二阶微分进行加权的峰锐化算法来提高峰分辨率,解决拖尾峰和前延峰的问题。然后,对锐化后的信号进行连续小波变换,实现信号去噪并得到谱峰的粗略参数。最后,将这些粗略参数作为曲线拟合的输入,通过非线性拟合得到最终精确的拟合参数,解决了大量峰重叠情况下的重叠峰分峰问题。理论分析和实验结果表明,解析后的分离度在仿真原始分离度上均有一定提升。与小波变换法、交点垂线法和比例分配法相比,该方法可以更加准确地实现重叠峰分峰。     

改进的NURBS曲面片拼接算法

研究了已网格化的曲面片之间的拼接技术并对现有的拼接算法进行了改进。首先,根据哈特利-贾德的弦长参数化算法求取非均匀有理B样条（NURBS）曲线上的节点向量,利用节点向量和曲线反求出控制顶点,并采用投影变换的方法求出权因子。其次,根据要求调整曲面片上的控制顶点,使曲面片之间达到G1连续。最后,再对已拼接好的曲面片上的控制顶点进行整体修改,重新排列整张曲面片上的控制顶点,从而实现曲面片的无缝拼接。用专业的三维造型软件对拼接后合并的曲面片进行了测试,结果表明,该方法在保证曲面片之间G1连续的情况下可使多块曲面片实现无缝拼接,无缝拼接试验中的平均误差为0.0049°。     

阳极溶出镉在线分析仪的同步校正方法

针对基于阳极溶出伏安法水质镉在线分析仪溶出峰的电流值受环境温度影响问题,提出了一种同步校正的改进方法。该方法利用样品和校正液溶出峰电流信号随温度同步变化特性,在一个样品测量周期内同时进行校正液的测定,并将两者的溶出峰电流线性比较而计算出样品浓度。实验结果表明,镉溶出峰电流值随温度的升高而增大,当温度从5℃上升至43℃时,溶出峰电流值增大了近2.3倍,且影响机制为镉离子在工作电极表面扩散层的迁移速率主要受温度控制。采用改进的同步校正方法,镉在线仪器在5~43℃测量值的误差均小于10%,有效解决了仪器测量值对环境温度敏感问题。     

Influence of laser irradiation condition on a femtosecond laser-assisted tomographic atom probe

Influence of femtosecond laser pulse condition on the performance of an energy-compensated optical tomographic atom probe has been investigated. The unstable oscillator makes the mass peaks significantly broadened. Double 80 fs pulse train with 10 ns interval makes the mass peaks slightly shifted to the higher mass side. The mass peak shift corresponds to the fight time of ions triggered by laser pulsing. Chirping ratio for the laser pulses ranging from 80 fs to 10 ps is controlled by the pulse compressor for the fragile specimens such as oxide dispersion strengthen steel or insulator materials. A first-principle calculation for optical dielectric breakdown in diamond has been successfully demonstrated. It is shown that effective conductive increase has appeared at the laser intensity around 10¹³ W/cm².     

Accurate alignment of sets of images

Two modifications to the conventional procedure of cross-correlation are described, widely used for establishing the relative alignment of the members of a set of images from which a higher resolution or more interpretable restoration is sought. Both achieve a high and sharp peak in circumstances where the conventional peak is too ill defined to be recognizable; neither involves significant additional computation time. The more general method requires rough knowledge of the imaging conditions, but a variant applicable to images with axial resolution has no such requirement. In addition, a least-squares procedure is presented for achieving an optimum compromise between many pair-wise displacement measurements, preventing the accumulation of alignment errors across a set of images.     

确定无吸收薄膜光学参数的新方法

本文提出一种测量无吸收单层膜光学参数的新方法,它利用 T—λ曲线上的特定光学位相点求出单层膜的几何厚度,进而求出色散因子。     

A simple method to deposit palladium doped SnO2 thin films using plasma enhanced chemical vapor deposition technique

This work presents a simple method to deposit palladium doped tin oxide (SnO(2)) thin films using modified plasma enhanced chemical vapor deposition as a function of deposition temperature at a radio frequency plasma power of 150 W. Stannic chloride (SnCl(4)) was used as precursor and oxygen (O(2), 100 SCCM) (SCCM denotes cubic centimeter per minute at STP) as reactant gas. Palladium hexafluroacetyleacetonate (Pd(C(5)HF(6)O(2))(2)) was used as a precursor for palladium. Fine granular morphology was observed with tetragonal rutile structure. A peak related to Pd(2)Sn is observed, whose intensity increases slightly with deposition temperature. Electrical resistivity value decreased from 8.6 to 0.9 mΩ cm as a function of deposition temperature from 400 to 600 °C. Photoelectron peaks related to Sn 3d, Sn 3p3, Sn 4d, O 1s, and C 1s were detected with varying intensities as a function of deposition temperature.