Browsing by Author "Hsu, Long"

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A collective tracking method for preliminary sperm analysis
(2019-11-27)
Wei, Sung-Yang
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Chao, Hsuan-Hao
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Huang, Han-Ping
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Hsu, Chang Francis
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Li, Sheng-Hsiang
Background Total motile sperm count (TMSC) and curvilinear velocity (VCL) are two important parameters in preliminary semen analysis for male infertility. Traditionally, both parameters are evaluated manually by embryologists or automatically using an expensive computer-assisted sperm analysis (CASA) instrument. The latter applies a point-tracking method using an image processing technique to detect, recognize and classify each of the target objects, individually, which is complicated. However, as semen is dense, manual counting is exhausting while CASA suffers from severe overlapping and heavy computation. Methods We proposed a simple frame-differencing method that tracks motile sperms collectively and treats their overlapping with a statistical occupation probability without heavy computation. The proposed method leads to an overall image of all of the differential footprint trajectories (DFTs) of all motile sperms and thus the overall area of the DFTs in a real-time manner. Accordingly, a theoretical DFT model was also developed to formulate the overall DFT area of a group of moving beads as a function of time as well as the total number and average speed of the beads. Then, using the least square fitting method, we obtained the optimal values of the TMSC and the average VCL that yielded the best fit for the theoretical DFT area to the measured DFT area. Results The proposed method was used to evaluate the TMSC and the VCL of 20 semen samples. The maximum TMSC evaluated using the method is more than 980 sperms per video frame. The Pearson correlation coefficient (PCC) between the two series of TMSC obtained using the method and the CASA instrument is 0.946. The PCC between the two series of VCL obtained using the method and CASA is 0.771. As a consequence, the proposed method is as accurate as the CASA method in TMSC and VCL evaluations. Conclusion In comparison with the individual point-tracking techniques, the collective DFT tracking method is relatively simple in computation without complicated image processing. Therefore, incorporating the proposed method into a cell phone equipped with a microscopic lens can facilitate the design of a simple sperm analyzer for clinical or household use without advance dilution.
A microfluidic chip with a U-shaped microstructure array for multicellular spheroid formation, culturing and analysis
(2014-03-01)
Fu, Chien-Yu
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Tseng, Sheng-Yang
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Yang, Shih-Mo
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Hsu, Long
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Liu, Cheng-Hsien
Multicellular spheroids (MCS), formed by self-assembly of single cells, are commonly used as a three-dimensional cell culture model to bridge the gap between in vitro monolayer culture and in vivo tissues. However, current methods for MCS generation and analysis still suffer drawbacks such as being labor-intensive and of poor controllability, and are not suitable for high-throughput applications. This study demonstrates a novel microfluidic chip to facilitate MCS formation, culturing and analysis. The chip contains an array of U-shaped microstructures fabricated by photopolymerizing the poly(ethylene glycol) diacrylate hydrogel through defining the ultraviolet light exposure pattern with a photomask. The geometry of the U-shaped microstructures allowed trapping cells into the pocket through the actions of fluid flow and the force of gravity. The hydrogel is non-adherent for cells, promoting the formation of MCS. Its permselective property also facilitates exchange of nutrients and waste for MCS, while providing protection of MCS from shearing stress during the medium perfusion. Heterotypic MCS can be formed easily by manipulating the cell trapping steps. Subsequent drug susceptibility analysis and long-term culture could also be achieved within the same chip. This MCS formation and culture platform can be used as a micro-scale bioreactor and applied in many cell biology and drug testing studies.
A novel optoelectrofulidic system for cells/particles manipulation and sorting
(2010)
Yang, Shih-Mo
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Yu, Tung-Ming
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Huang, Hang-Ping
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Hsu, Long
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Liu, Cheng-Hsien
A novel optoelectrofulidic system integrated optical image concentration and alignment system, dielectrophoresis phenomenon, microfluidic and friendly real-time control interface is first reported in this article. A new application of photoconductive material oxotitanium phthalocyanine (TiOPc) for microparticle applying has been first described and demonstrated by our research group. Basis on the special character of the photoconductive material, a TiOPc-based optoelectronic tweezers (Ti-OET) is utilized for single and massive cells/particles manipulation. The objects wanted to be manipulated are defined with different behaviors (e.g., press, release, drag and move) using Flash (R) software when the cursor acts on them. It also reveals the application for biological application to form the cells trapping with three sorts of cells, HMEC-1, HepG2 and HEK293t. Another application of our optoelectrofulidic system is to fabricate a TiOPc-based flow cytometry chip which can be used for sorting the 15 mu m diameter particles with 105 mu m/s velocity. When the 10Vp. p. voltage and 45 kHz AC frequency apply on the top and button ITO electrode, the illuminated light pattern will become a spatially virtual switch inside the microchannel. The dielectrophoresis force between top ITO glass and button photoconductive layer controlled by the friendly interface will concentrate the cells/particles as a straight line and individually direct each one in different paths. In summary, we have established an optoelectronfulidic-based chip and spatially virtual switch system which are applied for cell pattern and particles sorting. In the future, this easy manipulation approach can place the full power of optoelectronfulidic chip into the biological operators' hands.
A time-delay calibrated method for cornea hysteresis and intraocular pressure measurement
(2016-04-01)
Wang, Kuo-Jen
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Tsai, Che-Liang
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Wang, Wai
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Hsu, Long
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Hsu, Ken-Yuh
The presence of cornea hysteresis (CH) in characterizing the intraocular pressure (IOP) of a human eye deteriorates the accuracy of IOP. To suppress CH, the pressure gauge of a tonometer must be located as close as possible to the cornea. However, this arrangement is unpractical because appropriate working distance to the cornea is required. In this paper, a time-delay calibrated (TDC) method is proposed to counteract the undesired effect of CH in characterizing the IOP. Employing this TDC method, the CH approaches to zero for most eyes measured.
A time-delay calibrated method for cornea hysteresis and intraocular pressure measurement
(2016-04)
Wang, Kuo-Jen
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Tsai, Che-Liang
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Wang, Wai
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Hsu, Long
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Hsu, Ken-Yuh
The presence of cornea hysteresis (CH) in characterizing the intraocular pressure (IOP) of a human eye deteriorates the accuracy of IOP. To suppress CH, the pressure gauge of a tonometer must be located as close as possible to the cornea. However, this arrangement is unpractical because appropriate working distance to the cornea is required. In this paper, a time-delay calibrated (TDC) method is proposed to counteract the undesired effect of CH in characterizing the IOP. Employing this TDC method, the CH approaches to zero for most eyes measured.
Adjustable-focus ultracompact endoscopic lens design with ultrahigh optical performance
(2018-02-10)
Chang, Yu-Shan
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Hsu, Long
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Huang, Kuang-Lung
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電子物理學系
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Department of Electrophysics
An internally focusing design is developed for a compact endoscopic lens to have optical performance close to the diffraction limit. When changing the working distance from infinity to a predetermined short distance, the overall system length and the field of view remain constant. It is numerically demonstrated that the diffraction-limit-like performance is maintained over a wide range of working distances, showing a novel capability of adjustable focuses. The design concept is numerically proven to be feasible and can enable very high-resolution examination for doctors checking the positions of biological entities through the immediate capture of clear images at different working distances. The corresponding lens configuration, PNN, is shown to be useful in achieving the high-resolution performance once the number of lens elements is four, where P and N are used to denote positive and negative optical power, respectively, for the lens groups. A corresponding tolerance analysis is also presented. (c) 2018 Optical Society of America
An easier way to improvement the trapping performance of optical tweezers by donut-shaped beam
(2010)
Tsai, Che-Liang
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Huang, Hang-Ping
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Hsu, Long
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Hsu, Ken-Yuh
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光電工程學系
In optical tweezers, it can be comprehended that the larger the inclination angle between the condensed laser beam and the optical axis contributes more to axial trapping force, while the central part of laser beam with smaller inclination angle contributes more transverse trapping force. Therefore donut-shaped beam is used to improve the problem of less-axial trapping for common optical tweezers. Some research reports have shown that the efficiency of a trapping force can be enhanced by using a donut-shaped beam. In this paper we present the dependence of the axial and the transverse components of a trapping force on the configuration of a focused donut-shaped beam. The simulation result will provide a simple and easy guide for optical tweezers users to adjust the configuration of a focused donut-shaped beam for optimal trapping performance.
An intuitive view of the origin of orbital angular momentum in optical vortices
(2006)
Tseng, Sheng-Yanng
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Hsu, Long
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電子物理學系
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Department of Electrophysics
A modulated laser beam by a phase pattern exp(il theta) can be focused by an objective into a ring-like optical vortex, where l is a constant and theta is the azimuth angle. The vortex is capable of trapping the particles nearby and circulating them along the ring. This phenomenon is often explained involving Fourier optics and the transfer of orbital angular momentum (OAM). Although Fourier optics transforms the electric field distribution of the modulated laser beam behind the phase pattern to that of the vortex, it does not include both the path and OAM of the photons of the electromagnetic wave. Therefore, it is difficult to further trace the transfer of OAM from the photons to the particles in the vortex. In this paper, we propose a simple and intuitive view to the origin of optical vortex. By analyzing the relationship of the intensity distributions between the phase of the phase pattern and the intensity of the vortex by utilizing Fourier transform, we propose that the phenomenon of vortex also involve the transfer of linear momentum on the vortex plane transversely.
An Investigation Study on Mode Mixing Separation in Empirical Mode Decomposition
(2019-01-01)
Huang, Han-Ping
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Wei, Sung-Yang
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Chao, Hsuan-Hao
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Hsu, Chang Francis
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Hsu, Long
Mode mixing is a limitation of the empirical mode decomposition (EMD) method appropriate for physiological signal analysis. In 2008, boundary condition map presented by Rilling and Flandrin provided the efficiency of separating the two components of a two-tone signal as a function of their amplitude and frequency ratios. Until 2019, their findings were still applied. However, their maps only give an uncertainty-like efficiency of mode mixing separation for two-tone signals. In this paper, we propose a criterion for mode mixing separation in EMD, which provides a binary judgment on mode mixing separation instead of the above-mentioned efficiency. By comparing the slopes of the two components, we found that the phenomenon of mode mixing occurs as the extrema of the high-tone component are suppressed by the low-tone component. Under this condition, the criterion shows the relation among their amplitude ratio, frequency ratio, and relative phase between the two components. Given with the values of the three parameters, one can affirm whether the two components are mixed according to the criterion. Accordingly, we derive a black/white three-dimensional (3D) map that plots the binary result of mode mixing in black or white as a function of the three parameters. Our map agrees with Rilling's map and the results obtained from our gait analysis. Among the 23 sets of center-of-mass trajectory signals, six sets encountered the mode mixing problem and their coordinates of the three parameters were found in the black region of the map, while the other 17 sets were in the white region.
Average Entropy: Measurement of disorder for cardiac RR interval signals
(2019-09-01)
Hsu, Chang Francis
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Lin, Ping-Yen
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Chao, Hsuan-Hao
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Hsu, Long
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Chi, Sien
We introduce average entropy (AE) as a disorder measure of heart rate time series. The AE measurement reflects both the probability distribution of all discrete values in a time series and the randomness of the series. The AE analysis is able to differentiate the congestive heart failure (CHF), the healthy, and the atrial fibrillation (AF) subjects for both short and long heart rate time series. The differentiation accuracy of AE is higher than 90%. In addition, since the meaning of "disorder" is easily confused with "complexity", we explore the relation between them by analyzing heart rate time series. Specifically, we demonstrate that the complexity measured by entropy of entropy (EoE) versus the disorder measured by AE plot of heart rate time series exhibits a distinct inverted U relation. (C) 2019 Elsevier B.V. All rights reserved.
Cell patterning via diffraction-induced optoelectronic dielectrophoresis force on an organic photoconductive chip
(2013)
Yang, Shih-Mo
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Tseng, Sheng-Yang
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Chen, Hung-Po
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Hsu, Long
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Liu, Cheng-Hsien
A laser diffraction-induced dielectrophoresis (DEP) phenomenon for the patterning and manipulation of individual HepG2 cells and polystyrene beads via positive/negative DEP forces is reported in this paper. The optoelectronic substrate was fabricated using an organic photoconductive material, TiOPc, via a spin-coating process on an indium tin oxide glass surface. A piece of square aperture array grid grating was utilized to transform the collimating He-Ne laser beam into the multi-spot diffraction pattern which forms the virtual electrodes as the TiOPc-coating surface was illuminated by the multi-spot diffraction light pattern. HepG2 cells were trapped at the spot centers and polystyrene beads were trapped within the dim region of the illuminated image. The simulation results of light-induced electric field and a Fresnel diffraction image illustrated the distribution of trapped microparticles. The HepG2 morphology change, adhesion, and growth during a 5-day culture period demonstrated the cell viability through our manipulation. The power density inducing DEP phenomena, the characteristics of the thin TiOPc coating layer, the operating ac voltage/frequency, the sandwiched medium, the temperature rise due to the ac electric fields and the illuminating patterns are discussed in this paper. This concept of utilizing laser diffraction images to generate virtual electrodes on our TiOPc-based optoelectronic DEP chip extends the applications of optoelectronic dielectrophoretic manipulation.
Comparison of backward-scattered detection and forward-scattered detection for measuring optical force in optical tweezers
(2010)
Su, Yi-Jr
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Hsu, Long
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電子物理學系
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Department of Electrophysics
Optical tweezers have become an important tool to measure forces in biology. The trapped particle displacements acquired from the position detection system are applied to calibrate trapping stiffness using power spectrum method. The near infrared light is typically used as a laser source to reduce the damage to a cell or cellular organelles and the biological objects can be held and moved by exerting piconewton forces. In force measurement, optical force strength is calculated by multiplying trapping stiffness and trapped bead displacement. Optical tweezers perform a wider range of experiments through the integration of a quadrant photodiode for position detection. Both forward-scattered detection and backward-scattered detection are the typical position detection. This study discussed both backward-scattered detection and forward-scattered detection that add a probing beam and their linear detection ranges that describe the precise position of the trapped bead. This work also discussed their linear detection ranges related to the distance between the two laser system focuses, confirming the optimum positions of the two focuses. The result indicated that the linear detection range of backward-scattered detection is longer than the forward-scattered detection. Hence, backward-scattered detection measures the longer displacement of the trapped bead in optical force measurement.
Concentration of Magnetic Beads Utilizing Light-Induced Electro-Osmosis Flow
(2011-10-01)
Yang, Shih-Mo
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Harishchandra, Punde Tushar
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Yu, Tung-Ming
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Liu, Ming-Huei
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Hsu, Long
Magnetic beads are widely utilized for separating biomolecules, DNA and RNA. Traditionally, bulk magnet is utilized for manipulation these particles but when it comes to microscale bulk magnet is not the efficient method. Here, we utilize an organic photoconductive material, TiOPc, to generate light-induced electro-osmosis flow on chip. The fabrication process is convenient to be handled by the researchers and biologists without cleanroom IC fabrication facility. When specifically designed light pattern is projected onto the TiOPc substrate, the conductivity of the organic material layer within the illuminating region increases and the charges are locally assembled on its surface to form a virtual electrode. With an external ac voltage of 5 Vpp at 10 kHz, numerous magnetic beads are attracted from the nonilluminating region toward the center of light-pattern illuminating region. Driven by the moving light image, the grouped magnetic beads can be manipulated and merged in a desired way or direction. The light manipulation process provides a flexible and convenient approach for in vitro control of magnetic beads. We expect that this light-driven technology would display a multifunctional platform for manipulation of microparticles.
Controlling the transverse momentum distribution of a light field via azimuth division of a hologram in holographic optical tweezers
(2011-12-01)
Tseng, Sheng-Yang
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Hsu, Long
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電子物理學系
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Department of Electrophysics
This study proposes a method for creating a light field with controlled distribution of transverse momentum (TM) by displaying a hologram only in an azimuth region that centers at theta(0) and has a range of Delta theta of a spatial light modulator in holographic optical tweezers. This study utilized ray optics to analyze the TM of the resultant field, revealing that the direction of the TM is determined by the center angle of the azimuth region and that the magnitude of the TM is proportional to sind(Delta theta/2), without regarding the intensity. The relationship was verified experimentally. In addition, this study demonstrated moving particles along a designed path and depleting particles by the fields. (C) 2011 Optical Society of America
Discrimination of Severity of Alzheimer's Disease with Multiscale Entropy Analysis of EEG Dynamics
(2020-02-01)
Hsu, Chang Francis
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Chao, Hsuan-Hao
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Yang, Albert C.
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Yeh, Chih-Wei
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Hsu, Long
Multiscale entropy (MSE) was used to analyze electroencephalography (EEG) signals to differentiate patients with Alzheimer's disease (AD) from healthy subjects. It was found that the MSE values of the EEG signals from the healthy subjects are higher than those of the AD ones at small time scale factors in the MSE algorithm, while lower than those of the AD patients at large time scale factors. Based on the finding, we applied the linear discriminant analysis (LDA) to optimize the differentiating performance by comparing the resulting weighted sum of the MSE values under some specific time scales of each subject. The EEG data from 15 healthy subjects, 69 patients with mild AD, and 15 patients with moderate to severe AD were recorded. As a result, the weighted sum values are significantly higher for the healthy than the patients with moderate to severe AD groups. The optimal testing accuracy under five specific scales is 100% based on the EEG signals acquired from the T4 electrode. The resulting weighted sum value for the mild AD group is in the middle of those for the healthy and the moderate to severe AD groups. Therefore, the MSE-based weighted sum value can potentially be an index of severity of Alzheimer's disease.
Dynamic manipulation and patterning of microparticles and cells by using TiOPc-based optoelectronic dielectrophoresis
(2010-06-15)
Yang, Shih-Mo
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Yu, Tung-Ming
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Huang, Hang-Ping
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Ku, Meng-Yen
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Hsu, Long
We develop light-driven optoelectronic tweezers based on the organic photoconductive material titanium oxide phthalocyanine. These tweezers function based on negative dielectrophoresis (nDEP). The dynamic manipulation of a single microparticle and cell patterning are demonstrated by using this light-driven optoelectronic DEP chip. The adaptive light patterns that drive the optoelectronic DEP onchip are designed by using Flash software to approach appropriate dynamic manipulation. This is also the first reported demonstration, to the best of our knowledge, for successfully patterning such delicate cells from human hepatocellular liver carcinoma cell line HepG2 by using any optoelectronic tweezers. (C) 2010 Optical Society of America
Entropy of Entropy: Measurement of Dynamical Complexity for Biological Systems
(2017-10-01)
Hsu, Chang Francis
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Wei, Sung-Yang
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Huang, Han-Ping
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Hsu, Long
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Chi, Sien
Healthy systems exhibit complex dynamics on the changing of information embedded in physiologic signals on multiple time scales that can be quantified by employing multiscale entropy (MSE) analysis. Here, we propose a measure of complexity, called entropy of entropy (EoE) analysis. The analysis combines the features of MSE and an alternate measure of information, called superinformation, useful for DNA sequences. In this work, we apply the hybrid analysis to the cardiac interbeat interval time series. We find that the EoE value is significantly higher for the healthy than the pathologic groups. Particularly, short time series of 70 heart beats is sufficient for EoE analysis with an accuracy of 81% and longer series of 500 beats results in an accuracy of 90%. In addition, the EoE versus Shannon entropy plot of heart rate time series exhibits an inverted U relationship with the maximal EoE value appearing in the middle of extreme order and disorder.
Fabrication of PEG Hydrogel Microstructures in Microfluidic System for Multicellular Spheroid Formation, Culturing and Analysis
(2011)
Fu, Chien-Yu
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Tseng, Sheng-Yang
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Yang, Shih-Mo
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Hsu, Long
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Liu, Cheng-Hsien
This study presents a novel microfluidic device for 3 dimension cell culturing and analysis. Through defining the exposure to ultra-violet light by a photomask, localized photopolymerization of poly (ethylene glycol) diacrylate hydrogels form biocompatible and permselective microstructures within a microfluidic device. The designed geometry of microstructures allowed cells to be trapped into structures and to form spheroids in situ. Subsequent analysis and long-term three-dimension cell culture can achieve within the same device. This technique may apply as a microscale bioreactor or a platform for spheroid-based drug screening and study.
Fast trapping force calculation by utilizing graphic processing unit
(2012)
Tseng, Sheng-Yang
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Chang, Ai-Tang
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Luo, Chih-Wei
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Hsu, Long
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Kobayashi, Takayoshi
Fast calculation of trapping force provides a more direct way for optimizing designs of optical systems which generate optical traps. In this study, a graphic processing unit (GPU), NVIDIA GTX 275, is used to boost the speed of trapping efficiency calculation under ray optics approximation. The codes of trapping efficiency calculation are implemented in C++. The computing power of GPU is utilized through compute unified architecture device (CUDA) toolkit 4.0. The computing speed is compared with that of central processing unit (CPU), Intel Core 2 Quad Q9550. Over 100x speedup is achieved when single-precision floating-point numbers were used in the calculation.
Finger-powered agglutination lab chip with CMOS image sensing for rapid point-of-care diagnosis applications
(2020-01-21)
Lu, Chung Hsiang
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Shih, Ting-Sheng
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Shih, Po-Chen
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Pendharkar, Gaurav Prashant
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Liu, Cheng-En
Agglutination is an antigen-antibody reaction with visible expression of aggregation of the antigens and their corresponding antibodies. Applications extend to the identification of acute bacterial infection, hemagglutination, such as blood grouping, and diagnostic immunology. Our finger-powered agglutination lab chip with external CMOS image sensing was developed to support a platform for inexpensive, rapid point-of-care (POC) testing applications related to agglutination effects. In this paper, blood grouping (ABO and Rh grouping) was utilized to demonstrate the function of our finger-powered agglutination lab chip with CMOS image sensing. Blood antibodies were preloaded into the antibody reaction chamber in the lab chip. The blood sample was pushed through the antibody reaction chamber using finger-powered pressure actuation to initiate a hemagglutination reaction to identify the blood type at the on-chip detection area using our homemade CMOS image sensing mini-system. Finger-powered actuation without the need for external electrical pumping is excellent for low-cost POC applications, but the pumping liquid volume per finger push is hard to control. In our finger-powered agglutination lab chip with CMOS image sensing, we minimized the effects of different finger push depths and achieved robust performance for the test results with different push depths. The driving sample volume per finger push is about 0.79 mm(3). For different chips and different pushes, the driven sample volume per finger push was observed to vary in the range of 0.64 to 1.18 mm(3). The red blood cells were separated from the plasma on-chip after the whole blood sample was finger pumped and before the red blood cells reached the antibody chamber via an embedded plasma-separation membrane. Our homemade CMOS image mini-system robustly read and identified the agglutination results on our agglutination lab chip.