Deep brain stimulation (DBS) is a technology designed to treat some neural disorders and abnormal neuronal activity such as Parkinson's disease. However, it has not been clear how periodic electrical stimuli can r...
详细信息
Deep brain stimulation (DBS) is a technology designed to treat some neural disorders and abnormal neuronal activity such as Parkinson's disease. However, it has not been clear how periodic electrical stimuli can reduce the symptoms. The objective of this study is to test the hypothesis that the periodic signals can enhance endogenous signals in the network through stochastic resonance in a physiologically realistic neuron model of the central nervous system. In the computer simulations, two kinds of periodic waveforms were applied as extracellular sub-threshold electric stimuli, while the peak-to-baseline ratio (PBR) calculated from the power spectra of transmembrane potentials at the soma was used to quantify the detection of weak signals. It was shown that the PBR was increased, maximized, and then decreased as the frequency the periodic pulsatile stimuli increased, implying a resonance phenomenon depending on the frequency. It was concluded that the periodic electric stimuli utilized for DBS could play a key role in improving detection of weak signals when the amplitude and frequency of electric stimuli are appropriately set. Moreover, these results suggests a novel phenomenon for frequency dependent stochastic resonance capable of enhancing signals at specific frequencies.
We demonstrate the resonance wavelength and quality factor dependence of 50nm defect-hole placement within photonic crystal L3 microcavities. Proper placement of defect-holes leads to a 12% increase in photonic crysta...
详细信息
With the initial completion of Human Genome Project, the post-genomic era is coming. Although the genome map of human has been decoded, the roles that each segment of sequences acts are not totally discovered. On the ...
详细信息
With the initial completion of Human Genome Project, the post-genomic era is coming. Although the genome map of human has been decoded, the roles that each segment of sequences acts are not totally discovered. On the other hand, with the rapid expansion of sequence information, the issues of data compilation and data storage are increasingly important. Recently, a “Web-based Human Genome Database System” is implemented in National Taiwan University Hospital. The achievement of this system is that it integrates the modules of sequence alignment and data compression on genome. For goals of secure accessing this system over insecure networks, protocols of user authentication become more important. They are able to ensure the security of data transmission and users' communication. In this paper, a password-based user authentication scheme, because of its convenience, efficiency, and property of simplicity for human memory, is proposed for the system.
Previously we proposed using an interpolated average CT (IACT) method for attenuation correction (AC) in PET, which is a good low-dose approximation of cine average CT (CACT) to reduce misalignments and improve quanti...
详细信息
Previously we proposed using an interpolated average CT (IACT) method for attenuation correction (AC) in PET, which is a good low-dose approximation of cine average CT (CACT) to reduce misalignments and improve quantification in PET/CT. This study aims to evaluate the performance of IACT for different motion amplitudes. We used the digital 4D Extended Cardiac Torso phantom (XCAT) to simulate maximum of 2 cm, 3 cm and 4 cm respiratory motions. The respiratory cycle was divided into 13 phases, with average activity and attenuation maps to represent 18 F-FDG distribution with average respiratory motions and CACT respectively. The end-inspiration, end-expiration and the mid-respiratory phases represented 3 different helical CTs (HCT-1, HCT-5 and HCT-8). The IACTs were generated using: (a) 2 extreme + 11 interpolated phases (IACT 2o11i ); (b) 2 phases right after the extreme phases + 11 interpolated phases (IACT 2s11i ); (c) 4 original + 9 interpolated phases (IACT 4o9i ). A spherical lesion with target-to-background ratio (TBR) of 4:1 and diameter of 25 mm was placed in the base of right lung. The noise-free and noisy sinograms with attenuation modeling were generated and reconstructed with different noise-free and noisy AC maps (CACT, HCTs and IACTs) by STIR (Software for Tomographic Image Reconstruction) respectively, using OS-EM with up to 300 updates. Normalized-mean square error (NMSE), mutual information (MI), TBR and image profiles were analyzed. The PET reconstructed images with AC using CACT showed least difference as compared to the original phantom, followed by IACT4 o9i , IACT 2o11i , IACT 2s11i , HCT-5 and HCT-1/HCT-8. Significant artifacts were observed in the reconstructed images using HCTs for AC. The MI differences between IACT 2o11i and IACT 4o9i /CACT were 2s11i was still comparable to IACT 2o11i with difference of
We demonstrate the resonance wavelength and quality factor dependence of 50nm defect-hole placement within photonic crystal L3 microcavities. Proper placement of defect-holes leads to a 12% increase in photonic crysta...
详细信息
ISBN:
(纸本)9781557529107
We demonstrate the resonance wavelength and quality factor dependence of 50nm defect-hole placement within photonic crystal L3 microcavities. Proper placement of defect-holes leads to a 12% increase in photonic crystal sensor detection sensitivity.
Background: In bioinformatics projects, scientific workflow systems are widely used to manage computational procedures. Full-featured workflow systems have been proposed to fulfil the demand for workflow management. H...
详细信息
Background: In bioinformatics projects, scientific workflow systems are widely used to manage computational procedures. Full-featured workflow systems have been proposed to fulfil the demand for workflow management. However, such systems tend to be over-weighted for actual bioinformatics practices. We realize that quick deployment of cutting-edge software implementing advanced algorithms and data formats, and continuous adaptation to changes in computational resources and the environment are often prioritized in scientific workflow management. These features have a greater affinity with the agile software development method through iterative development phases after trial and error. Here, we show the application of a scientific workflow system Pwrake to bioinformatics workflows. Pwrake is a parallel workflow extension of Ruby's standard build tool Rake, the flexibility of which has been demonstrated in the astronomy domain. Therefore, we hypothesize that Pwrake also has advantages in actual bioinformatics workflows. Findings. We implemented the Pwrake workflows to process next generation sequencing data using the Genomic Analysis Toolkit (GATK) and Dindel. GATK and Dindel workflows are typical examples of sequential and parallel workflows, respectively. We found that in practice, actual scientific workflow development iterates over two phases, the workflow definition phase and the parameter adjustment phase. We introduced separate workflow definitions to help focus on each of the two developmental phases, as well as helper methods to simplify the descriptions. This approach increased iterative development efficiency. Moreover, we implemented combined workflows to demonstrate modularity of the GATK and Dindel workflows. Conclusions: Pwrake enables agile management of scientific workflows in the bioinformatics domain. The internal domain specific language design built on Ruby gives the flexibility of rakefiles for writing scientific workflows. Furthermore, readability
The real-time detection of harmful algal bloom (HAB)-causing organisms is crucial to preventing human illness and death, animal mortalities, and significant economic losses for coastal and fishing communities. However...
详细信息
The real-time detection of harmful algal bloom (HAB)-causing organisms is crucial to preventing human illness and death, animal mortalities, and significant economic losses for coastal and fishing communities. However, most identification schemes are time-consuming and costly, which limit their use for rapid risk assessment. To address this problem, a simple colorimetric test for the HAB-causing Alexandrium fundyense/tamarense/catanella dinoflagellate species complex is presented. This work integrates an indicator dye-based bioassay for detecting toxigenic Alexandrium RNA with a custom-built two-color detector. A peptide nucleic acid (PNA) probe is used to capture target RNA, and the formation of the PNA-RNA duplex is visible as a solution color change from blue to purple with the addition of the cyanine dye 3,3'-diethyldithiacarbocyanine iodide (DiSC 2 (5)). PNA-RNA hybridization and discrimination against mismatched sequences is achieved within minutes at 25°C. Hybridization signals obtained from the colorimeter are comparable to those from a benchtop spectrophotometer. The advantages of this method represent a step towards field-compatible, easy-to-use and inexpensive detection schemes that require minimal training for successful use.
Node failures in Wireless Sensor Networks composed by static sensor nodes are common due to the nature of the sensor devices and the usually harsh environments in which they are deployed. Node failures can diminish th...
详细信息
Node failures in Wireless Sensor Networks composed by static sensor nodes are common due to the nature of the sensor devices and the usually harsh environments in which they are deployed. Node failures can diminish the performance of the network as a whole, thus affecting its functionality in delivering the desired services. For instance, significant regions can become uncovered due to failure of several nearby nodes. This paper reports a study about the use of mobile sensor nodes acting in cooperation with static ones in order to fill gaps created by faulty static nodes. The proposed fault handling mechanism presents alternative policies with pros and cons, depending on the user priorities imposed to the system and the occurrence of failures. A discussion about this topic is presented based on results obtained by simulation of the proposed mechanisms.
An experiment was performed for the observation of H emission induced in a cooled laser-induced atmospheric pressure gas plasma of He atoms in their metastable excited state. The strong H emission detected clearly est...
详细信息
In this paper we introduce an adaptive fuzzy neural network framework for classification of data stream using a partially supervised learning algorithm. The framework consists of an evolving granular neural network ca...
详细信息
暂无评论