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1.
This study describes the development of a simple, enzyme-free, label-free, sensitive, and selective system for detecting adenosine based on the use of Tween 20-stabilized gold nanoparticles (Tween 20-AuNPs) as an efficient fluorescence quencher for boron dipyrromethene-conjugated adenosine 5′-triphosphate (BODIPY-ATP) and as a recognition element for adenosine. BODIPY-ATP can interact with Tween 20-AuNPs through the coordination between the adenine group of BODIPY-ATP and Au atoms on the NP surface, thereby causing the fluorescence quenching of BODIPY-ATP through the nanometal surface energy transfer (NSET) effect. When adenosine attaches to the NP surface, the attached adenosine exhibits additional electrostatic attraction to BODIPY-ATP. As a result, the presence of adenosine enhances the efficiency of AuNPs in fluorescence quenching of BODIPY-ATP. The AuNP-induced fluorescence quenching of BODIPY-ATP progressively increased with an increase in the concentration of adenosine; the detection limit at a signal-to-noise ratio of 3 for adenosine was determined to be 60 nM. The selectivity of the proposed system was more than 1000-fold for adenosine over any adenosine analogs and other nucleotides. The proposed system combined with a phenylboronic acid-containing column was successfully applied to the determination of adenosine in urine. 相似文献
2.
Multi-sensor data fusion is an evolving technology whereby data from multiple sensor inputs are processed and combined. The data derived from multiple sensors can, however, be uncertain, imperfect, and conflicting. The present study is undertaken to help contribute to the continuous search for viable approaches to overcome the problems associated with data conflict and imperfection. Sensor readings, represented by belief functions, have to be fused according to their corresponding weights. Previous studies have often estimated the weights of sensor readings based on a single criterion. Mono-criteria approaches for the assessment of sensor reading weights are, however, often unreliable and inadequate for the reflection of reality. Accordingly, this work opts for the use of a multi-criteria decision aid. A modified Analytical Hierarchy Process (AHP) that incorporates several criteria is proposed to determine the weights of a sensor reading set. The approach relies on the automation of pairwise comparisons to eliminate subjectivity and reduce inconsistency. It assesses the weight of each sensor reading, and fuses the weighed readings obtained using a modified average combination rule. The efficiency of this approach is evaluated in a target recognition context. Several tests, sensitivity analysis, and comparisons with other approaches available in the literature are described. 相似文献
3.
Alexander J. Marshall 《Analytica chimica acta》2004,527(1):13-20
Holographic sensors for monitoring ionic strength have been fabricated from charged sulphonate and quaternary ammonium monomers, incorporated into thin, polymeric hydrogel films which were transformed into volume holograms. The diffraction wavelength or reflected colour of the holograms was used to characterise their swelling or de-swelling behaviour as a function of ionic strength in various media. The effects of co-monomer structure, buffer composition, ion composition, pH and temperature were evaluated, whilst the reversibility and reproducibility of the sensor was also assessed. An acrylamide-based hologram containing equal molar amounts of negatively and positively charged monomers was shown to be able to quantify ionic strength independent of the identity of the ionic species present in the test solution. The sensor was fully reversible, free of hysteresis and exhibited little response to pH between 3 and 9 and temperature within the range 20-45 °C. The system was successfully used to quantify the ionic strength of milk solutions, which contain a complex mixture of ions and biological components. 相似文献
4.
Masashi Ohkawa Yuki Shirai Takeshi Goto Seishi Sekine Takashi Sato 《Fiber and Integrated Optics》2002,21(2):105-113
In this paper, a silicon-based integrated optic pressure sensor using an intermodal interference between the fundamental TM-like and TE-like modes is described. The sensor consists of a micromachined rectangular diaphragm and a straight polystyrene optical waveguide passing over the diaphragm. Its sensitivity is theoretically known to be strongly dependent on the position of the waveguide over the diaphragm. To experimentally investigate such dependence, we fabricated a sensor with a 1.2 mm ×10 mm ×20 μm diaphragm, over which waveguides were placed at 50 μm intervals. The measured phase sensitivity was 98 mrad/kPa for the waveguide nearest to the diaphragm edge. The measurement was also carried out for the other waveguides. As theoretically expected, the largest sensitivity was obtained for the waveguide nearest to the edge. 相似文献
5.
一种新的WDM光网中的共享链路保护策略 总被引:2,自引:2,他引:0
研究了WDM光网中的链路保护问题.提出了一种新的共享链路保护策略--基于SRLG的共享链路保护策略(SRLG-SLP).SRLG(共享风险链路组)定义了对一条工作光通道分配保护资源时的资源可用性的约束.它规定任意两条有着同样故障风险或者说处于同一个SRLG的工作光通道不能利用同样的保护资源.另外,还提出了一种更加符合实际的单链路故障模型,其中链路故障间隔时间和链路故障保持时间被考虑作为两个独立的变量.基于该链路故障模型,通过大量的仿真试验,比较了专用链路保护(DLP)、共享链路保护(SLP)和提出的SRLG-SLP保护策略的资源利用率、保护效率以及业务中断率.结果显示,我们提出的SRLG-SLP在保护效率和业务中断率方面的保护性能远好于DLP和SLP,但会牺牲一些资源利用率. 相似文献
6.
7.
Hadi Mohammadi Bidhandi 《Annals of Operations Research》2006,143(1):237-250
This paper develops a mathematical model for project time compression problems in CPM/PERT type networks. It is noted this
formulation of the problem will be an adequate approximation for solving the time compression problem with any continuous
and non-increasing time-cost curve. The kind of this model is Mixed Integer Linear Program (MILP) with zero-one variables,
and the Benders' decomposition procedure for analyzing this model has been developed. Then this paper proposes a new approach
based on the surrogating method for solving these problems. In addition, the required computer programs have been prepared
by the author to execute the algorithm. An illustrative example solved by the new algorithm, and two methods are compared
by several numerical examples. Computational experience with these data shows the superiority of the new approach. 相似文献
8.
A novel measurement method of temperature based on the phenomena that the phase difference between principle polarization states in the optical retarder is function of temperature is described. The polarization state of optical beam is changed as it passes through the optical retarder, which depends on the temperature. The temperature of optical retarder is determined by comparison of the power difference between principal polarization states. We demonstrate successfully the temperature measurement by using a polarization maintaining fiber as the optical retarder. With a 100 mm length of the fiber optic retarder, the change rate of phase difference on temperature was 0.236 rad/°C and the measurement error was ±0.038°C over the temperature range of −2.6 – +3.4°C. With a 11.5 mm length of the fiber optic retarder, the change rate of phase difference on temperature was 0.021 rad/°C and the measurement error was ±0.79°C over the temperature range of −8.5 – +86.5°C. 相似文献
9.
J. M. Kumpula J. Saramäki K. Kaski J. Kertész 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,56(1):41-45
According to Fortunato and Barthélemy, modularity-based community detection
algorithms have a resolution threshold such that small communities in a large
network are invisible. Here we generalize their work and show that the q-state
Potts community detection method introduced by Reichardt and Bornholdt
also has a resolution threshold. The model contains a parameter by which this threshold can be tuned, but no a priori principle
is known to select the proper value.
Single global optimization criteria do not seem capable for detecting all
communities if their size distribution is broad. 相似文献
10.
首先将无线传感器网络的路由问题转化成求解最小Steiner树问题,然后给出了求解无线传感器网络路由的蚁群优化算法,并对算法的收敛性进行了证明.最后对找到最优解后信息素值的变化进行了分析.即在限制信息素取值的条件下,当迭代次数充分大时,该算法能以任意接近于1的概率找到最优解,并且当最优解找到后,最优树边上的信息素单调增加,而最优解以外边上的信息素在有限步达到最小值. 相似文献