Browsing by Author "Chang, Wei-Ting"

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A simple method using Pyrosequencing (TM) to identify de novo SNPs in pooled DNA samples
(2011-03-01)
Lin, Yeong-Shin
;
Liu, Fu-Guo Robert
;
Wang, Tzi-Yuan
;
Pan, Cheng-Tsung
;
Chang, Wei-Ting
A practical way to reduce the cost of surveying single-nucleotide polymorphism (SNP) in a large number of individuals is to measure the allele frequencies in pooled DNA samples. Pyrosequencing (TM) has been frequently used for this application because signals generated by this approach are proportional to the amount of DNA templates. The Pyrosequencing (TM) pyrogram is determined by the dispensing order of dNTPs, which is usually designed based on the known SNPs to avoid asynchronistic extensions of heterozygous sequences. Therefore, utilizing the pyrogram signals to identify de novo SNPs in DNA pools has never been undertook. Here, in this study we developed an algorithm to address this issue. With the sequence and pyrogram of the wild-type allele known in advance, we could use the pyrogram obtained from the pooled DNA sample to predict the sequence of the unknown mutant allele (de novo SNP) and estimate its allele frequency. Both computational simulation and experimental Pyrosequencing(TM) test results suggested that our method performs well. The web interface of our method is available at http://life.nctu.edu.tw/similar to yslin/PSM/.
Comparison of Home and Ambulatory Blood Pressure Measurements in Association With Preclinical Hypertensive Cardiovascular Damage
(2019-03-01)
Lin, Ting-Tse
;
Juang, Jimmy Jyh-Ming
;
Lee, Jen-Kuang
;
Tsai, Chia-Ti
;
Chen, Chen-Huan
Objective: To evaluate whether home or ambulatory blood pressure (BP) monitoring was associated with preclinical hypertensive cardiovascular target organ damage (TOD). Methods: We enrolled participants with prehypertension and stage 1 hypertension from 11 medical centers within the Taiwan hypertension-associated cardiac disease consortium. Recordings of clinical BP measurement, ambulatory BP monitoring for 24 hours, and home BP monitoring during morning and evening were made. The measured parameters of target organ damage included left ventricular mass index (LVMI), left atrial volume index (LAVI), and carotid-femoral pulse wave velocity (PWV). Results: Data were collected from 561 study participants (mean age, 65.0 +/- 10.8 years; men, 61.3%). Morning and evening home BP values were slightly higher than the daytime and nighttime ABP values (difference for systolic morning-daytime/evening-nighttime, 7.3 +/- 14.2/11.3 +/- 18.5 mm Hg, P <.001; for diastolic, 5.4 +/- 9.4/ 7.3 +/- 12.1, P <.001). Daytime ambulatory (r = 0.114), nighttime ambulatory (r = 0.130), morning home (r = 0.310), and evening home (r = 0.220) systolic BPs (SBPs) were all associated with LVMI (all P <.05). The correlation coefficient was significantly greater for the relationship between daytime home SBP and LVMI than for the relationship between ambulatory SBP and LVMI (P <.01). The goodness of fit of the association between SBP and LVMI improved by adding home daytime SBP to the other SBPs (P <.001). Similar findings were observed for LAVI, but not for PWV. Conclusion: These findings indicate that morning SBP assessed by home monitoring appears to be a better predictor than other BP measures to determine preclinical hypertensive cardiovascular damage in patients with early-stage hypertension.
Investigation of efficiency droop for InGaN-based UV light-emitting diodes with InAlGaN barrier
(2011-05-23)
Tu, Po-Min
;
Chang, Chun-Yen
;
Huang, Shih-Cheng
;
Chiu, Ching-Hsueh
;
Chang, Jet-Rung
The efficiency droop in InGaN-based UV light emitting device (LED) with AlGaN and InAlGaN barrier is investigated. Electroluminescence results indicate that the light performance of quaternary LEDs can be enhanced by 25% and 55% at 350 mA and 1000 mA, respectively. Furthermore, simulations show that quaternary LEDs exhibit 62% higher radiative recombination rate and low efficiency degradation of 13% at a high injection current. We attribute this improvement to increasing of carrier concentration and uniform redistribution of carriers. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3591967]
Near -infrared optical reflectance microspectroscopy examining atrioventricular valvular rhythm of wildtype larval zebrafish as a pre -stage cardiac drug toxicity assay
(2020-06-01)
Hsieh, Hao-Chun
;
Chang, Wei-Ting
;
Hu, Po-Sheng
;
光電系統研究所
;
影像與生醫光電研究所
Reduction of efficiency droop in InGaN-Based UV Light-Emitting Diodes with InAlGaN Barrier
(2012)
Chiu, Ching-Hsueh
;
Tu, Po-Min
;
Chang, Jet-Rung
;
Chang, Wei-Ting
;
Kuo, Hao-Chung
In this study, we fabricated and compared the performance of LEDs of InGaN-based UV MQWs active region with ternary AlGaN and quaternary InAlGaN barrier layers. HRXRD and TEM measurements show the two barriers are consistent with the lattice, and smooth morphology of quaternary InAlGaN layer can be observed in AFM. The electroluminescence results indicate that the light performance of the InGaN-based UV LEDs can be enhanced effectively when the conventional LT AlGaN barrier layers are replaced by the InAlGaN barrier layers. Furthermore, simulation results show that InGaN-based UV LEDs with quaternary InAlGaN barrier exhibit higher radiative recombination rate about 62% and low efficiency droop about 13% at a high injection current. We attribute this change to a drastic improvement from increasing of carrier concentration and redistribution of carriers, because of reduction of scatterings due to better morphology in the transverse carrier transport through the InGaN/InAlGaN MQWs.
Reduction of Efficiency Droop in Semipolar (1(1)over-bar01) InGaN/GaN Light Emitting Diodes Grown on Patterned Silicon Substrates
(2011-01-01)
Chiu, Ching-Hsueh
;
Lin, Da-Wei
;
Lin, Chien-Chung
;
Li, Zhen-Yu
;
Chang, Wei-Ting
We present a study of semi-polar (1 (1) over bar 01) InGaN-based light emitting diodes (LEDs) grown on patterned (001) Si substrates by atmospheric-pressure metal organic chemical vapor deposition. A transmission electron microscopy image of the semi-polar template shows that the threading dislocation density was decreased significantly. From electroluminescence measurement, semi-polar LEDs exhibit little blue-shift and low efficiency droop at a high injection current because the reduction of the polarization field not only made the band diagram smoother but also restricted electron overflow to the p-GaN layer as shown in simulations. These results indicate that semi-polar InGaN-based LEDs can possess a high radiative recombination rate and low efficiency droop at a high injection current. (C) 2011 The Japan Society of Applied Physics
Reduction of Efficiency Droop in Semipolar (1(1)over-bar01) InGaN/GaN Light Emitting Diodes Grown on Patterned Silicon Substrates (vol 4, 012105, 2011)
(2011-03-01)
Chiu, Ching-Hsueh
;
Lin, Da-Wei
;
Lin, Chien-Chung
;
Li, Zhen-Yu
;
Chang, Wei-Ting