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991.
Pierre Peterlongo Nadia Pisanti Frdric Boyer Alair Pereira do Lago Marie-France Sagot 《Journal of Discrete Algorithms》2008,6(3):497-509
Similarity search in texts, notably in biological sequences, has received substantial attention in the last few years. Numerous filtration and indexing techniques have been created in order to speed up the solution of the problem. However, previous filters were made for speeding up pattern matching, or for finding repetitions between two strings or occurring twice in the same string. In this paper, we present an algorithm called Nimbus for filtering strings prior to finding repetitions occurring twice or more in a string, or in two or more strings. Nimbus uses gapped seeds that are indexed with a new data structure, called a bi-factor array, that is also presented in this paper. Experimental results show that the filter can be very efficient: preprocessing with Nimbus a data set where one wants to find functional elements using a multiple local alignment tool such as Glam, the overall execution time can be reduced from 7.5 hours to 2 minutes. 相似文献
992.
Determination of Ethambutol in Aqueous Medium Using an Inexpensive Gold Microelectrode Array as Amperometric Sensor 下载免费PDF全文
A. E. B. Lima G. E. Luz Jr N. C. Batista E. Longo L. S. Cavalcante R. S. Santos 《Electroanalysis》2016,28(5):985-989
In this paper, gold microelectrode array (Au‐MEA) were employed to determination of ethambutol in aqueous medium. Au‐MEA was constructed with an electronic microchip integrated circuit. The standard curve (analytical curve) was constructed for a single microelectrode (ME) in a concentration range of 5.0×10?5 to 2.0×10?3 mol L?1, allowing estimation of both the limit of detection (LOD) (4.73×10?5 mol L?1) and the limit of quantification (LOQ) (1.57×10?4 mol L?1) for ethambutol. When the MEA was utilized, the LOD and LOQ were 1.55×10?7 and 5.18×10?7 mol L?1, respectively. Our results indicated that Au‐MEA can be utilized as amperometric sensors for ethambutol determination in aqueous media. 相似文献
993.
Molecular Imaging of Biological Samples on Nanophotonic Laser Desorption Ionization Platforms 下载免费PDF全文
Sylwia A. Stopka Charles Rong Dr. Andrew R. Korte Dr. Sridevi Yadavilli Dr. Javad Nazarian Dr. Trust T. Razunguzwa Dr. Nicholas J. Morris Prof. Akos Vertes 《Angewandte Chemie (International ed. in English)》2016,55(14):4482-4486
Mass spectrometry imaging (MSI) is a comprehensive tool for the analysis of a wide range of biomolecules. The mainstream method for molecular MSI is matrix‐assisted laser desorption ionization, however, the presence of a matrix results in spectral interferences and the suppression of some analyte ions. Herein we demonstrate a new matrix‐free MSI technique using nanophotonic ionization based on laser desorption ionization (LDI) from a highly uniform silicon nanopost array (NAPA). In mouse brain and kidney tissue sections, the distributions of over 80 putatively annotated molecular species are determined with 40 μm spatial resolution. Furthermore, NAPA‐LDI‐MS is used to selectively analyze metabolites and lipids from sparsely distributed algal cells and the lamellipodia of human hepatocytes. Our results open the door for matrix‐free MSI of tissue sections and small cell populations by nanophotonic ionization. 相似文献
994.
Atmospheric Electric Potential Gradient (PG) measurements were carried out in three sites forming a triangular array in Southern Portugal. The campaign was performed during the summer, characterized by Saharan dust outbreaks; 16th–17th July 2014 dust event is considered. Short time-scale oscillations of the PG at two of the stations and a mid time-scale suppression of the PG in the three stations are found. Results are interpreted as evidencing long-range dust electrification; attributed to the air-Earth electrical current creating a bipolar charge distribution inside of the dust layer. The relevance of using arrays of sensors, instead of single sited, is highlighted. 相似文献
995.
Chemical modifications on recessed microelectrode array, achieved via electrodeposition techniques are reported here. Silicon-based gold microelectrode arrays of 10 μm microband and microdisc array were selected and functionalised using sol-gel and nanoporous gold (NPG) respectively. For electrochemically assisted self-assembly (EASA) formati6154on of sol-gel, electrode surface was first pre-treated with a self-assembled partial monolayer of mercaptopropyltrimethoxysilane (MPTMS) before transferring it into the sol containing cetyltrimethyl ammonium bromide (CTAB)/tetraethoxysilane (TEOS):MPTMS (90:10) precursors. A cathodic potential is then applied. It was found that larger current densities were required in ensuring successful film deposition when moving from macro- to micro- dimensions. For NPG modification, a chemical etching process called dealloying was employed. NPG of three different thicknesses have been successfully deposited. All the modified and functionalized microelectrode arrays were characterized by both optical (SEM) and electrochemical analysis (cyclic voltammetry and impedance spectroscopy). An increase in surface area and roughness has been observed and such will benefit for future sensing application. 相似文献
996.
次声测量与数据是次声各项研究的基础,而次声台阵是现代次声测量的主要形式,为此设计并建立了两个无人值守式实验次声四元台阵。描述了次声台阵的结构,对台站的仪器构成进行了说明,重点对其降噪管和通信系统进行了描述。降噪管为十字玫瑰花瓣型降噪管,给出了其降风噪性能。台站通信系统基于VPN进行架构,实现了数据的实时自动传输和FTP传输功能。实测结果表明实验台阵的噪声主要是由微气压、山背波和台阵附近的随机干扰噪声构成。台阵记录到了大量当量较小的区域地表采矿、采石微差爆破次声信号,也记录到了2013年2月15日俄罗斯陨石大爆炸事件相关的清晰的次声信号。分析结果表明,该次声台阵具有良好的性能,具有一定的推广价值。 相似文献
997.
为了解决普通AM参量阵产生的解调信号质量差、效率低等问题,设计了一个动态载波AM算法。以此算法为基础设计了一个DSP处理平台,并在此平台上实现了参量阵系统。经过系统硬件和软件两方面的优化设计,保证了算法运行的实时性和稳定性。最后,使用500Hz、800Hz和1100Hz的合成波作为测试信号,测试了系统输出的波形和参量阵前方5米处的频谱。对比测得的波形和理论波形,验证了此系统能够可靠地运行。对比普通AM和动态载波AM参量阵输出信号的频谱图,验证了动态载波AM参量阵能输出更好信噪比和能量更高的解调信号。 相似文献
998.
液相芯片技术同时检测莱克多巴胺、盐酸克伦特罗和沙丁胺醇 总被引:1,自引:0,他引:1
建立了一种同时检测兽药莱克多巴胺(RAC)、克伦特罗(CL)、沙丁胺醇(SAL)的多残留的新方法.采用液相悬浮芯片技术,基于间接竞争法的原理,将3种兽药抗原分别偶联到不同的荧光微球上作为探针,以藻红蛋白(PE)荧光标记二抗为信号,通过优化实验条件,分别建立3种兽药的标准曲线.基于特异性识别实验,建立3种兽药同时检测的标准曲线.结果表明,同时检测的3条曲线均呈现良好的线性相关,线性相关系数(R2)均大于0.99,RAC,CL和SAL的检测范围分别为1~ 500 μg/L,0.1~500μg/L,1~100μg/L,检出限分别为0.68,0.095和0.88 μg/L.与其它结构类似物的交叉反应率均低于1.5%,实际样品中的加标回收率令人满意. 相似文献
999.
1000.
针对水下低频声源的方位估计问题,基于基元紧密排列的二维矢量阵,建立了一种超指向性波束形成方法.根据矢量基元差分运算构建各阶多极子模型,获得了几乎与频率无关的模态函数,并经加权计算可在低频条件下实现超指向性波束,以解决阵列孔径对波束性能的限制.同时,结合输出信噪比最大准则所得波束,分析了超指向性波束形成算法的稳定性与波导的影响程度,探索模态阶数与阵列参数的选取原则.通过阵列性能的仿真计算与实际阵列的测量数据表明,该算法可在小尺寸阵列孔径下获得良好的阵列波束,兼具了水下线型超指向性阵和环形超指向性阵的优点,可有效实现水下低频声源的水平方位估计;且波束性能可通过调节模态阶数与基元间距以达到最佳,并受水下声波导多途与频散效应影响有限. 相似文献