Browsing by Author "Huang, Chia-Yen"

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Analysis of Quality Factor Enhancement in the Monolithic InGaN/GaN Nanorod Array
(2019-04-01)
Huang, Chia-Yen
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Tai, Tzu-Ying
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Hong, Kuo-Bin
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Kuo, Hao-Chung
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Lu, Tien-Chang
Whispering gallery mode (WGM) lasers and resonators are key building blocks for photonic integrated circuits. The quality factor and resonant wavelength are strong functions of the cavity size. Nanoscale WGM cavities suffer from a low-quality factor due to prominent scattering loss. However, the quality factor could be enhanced by forming an optically-coupled rod array or photonic molecules. Through simulations, we revealed how rod-to-rod optical coupling influenced the threshold pumping level and dominant mode selection, where the trend showed good agreement with the experimental observation. According to the simulation, the quality factor could be enhanced by up to eight times by forming a six-rod photonic molecule. The quality factor and effective mode were both superior to the single rods with the same wafer device footprint.
CDC42 Negatively Regulates Testis-Specific SEPT12 Polymerization
(2018-09-01)
Huang, Chia-Yen
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Wang, Ya-Yun
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Chen, Ying-Liang
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Chen, Mei-Feng
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Chiang, Han-Sun
Septin (SEPT) genes encode well-preserved polymerizing GTP-binding cytoskeletal proteins. The cellular functions of SEPTs consist of mitosis, cytoskeletal remodeling, cell polarity, and vesicle trafficking through interactions with various types of cytoskeletons. We discovered that mutated SEPTIN12 in different codons resulted in teratozoospermia or oligozoospermia. In mouse models with a defective Septin12 allele, sperm morphology was abnormal, sperm count decreased, and sperms were immotile. However, the regulators of SEPT12 are completely unknown. Some studies have indicated that CDC42 negatively regulates the polymerization of SEPT2/ 6/ 7 complexes in mammalian cell lines. In this study, we investigated whether CDC42 modulates SEPT12 polymerization and is involved in the terminal differentiation of male germ cells. First, through scanning electron microscopy analysis, we determined that the loss of Septin12 caused defective sperm heads. This indicated that Septin12 is critical for the formation of sperm heads. Second, CDC42 and SEPT12 were similarly localized in the perinuclear regions of the manchette at the head of elongating spermatids, neck region of elongated spermatids, and midpiece of mature spermatozoa. Third, wild-type CDC42 and CDC42Q61L (a constitutive-acting-mutant) substantially repressed SEPT12 polymerization, but CDC42T17N (a dominant-negative-acting mutant) did not, as evident through ectopic expression analysis. We concluded that CDC42 negatively regulates SEPT12 polymerization and is involved in terminal structure formation of sperm heads.
Collective Lasing Behavior of Monolithic GaN-InGaN Core-Shell Nanorod Lattice under Room Temperature
(2017-10-01)
Huang, Chia-Yen
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Lin, Jing-Jie
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Chang, Tsu-Chi
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Liu, Che-Yu
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Tai, Tzu-Ying
We demonstrated a monolithic GaN-InGaN core-shell nanorod lattice lasing under room temperature. The threshold pumping density was as low as 140 kW/cm(2) with a quality factor as high as 1940. The narrow mode spacing between lasing peaks suggested a strong coupling between adjacent whisper gallery modes (WGM), which was confirmed with the far field patterns. Excitation area dependent photoluminescence revealed that the long-wavelength lasing modes dominated the collective lasing behavior under a large excitation area. The excitation-area-dependent lasing behavior resulted from the prominent optical coupling among rods. According to the optical mode simulations and truncated-rod experiments, we confirmed that the fine-splitting of lasing peaks originated from the coupled supermodes existing in the periodic nanorod lattices. With wavelength-tunable active materials and a wafer-level scalable processing, patterning optically coupled GaN-InGaN core-shell nanorods is a highly practical approach for building various on-chip optical components including emitters and coupled resonator waveguides in visible and ultraviolet spectral range.
Comparing PI3K/Akt Inhibitors Used in Ovarian Cancer Treatment
(2020-03-03)
Wu, Yi-Hui
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Huang, Yu-Fang
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Chen, Chien-Chin
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Huang, Chia-Yen
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Chou, Cheng-Yang
Epithelial ovarian carcinoma (EOC) is the most lethal gynecological malignancy. Herein, we sought to determine the efficacy of phosphoinositide 3-kinase (PI3K)/Akt inhibition using three AZD compounds in a NOD-SCID xenograft mouse model and Akt regulation in a panel of eight ovarian cancer cell lines. Elevated Akt phosphorylation on Ser473 but not on Thr308 in cancerous tissues correlated with short progression-free survival (PFS), overall survival (OS), and death. AZD8835 and AZD8186 inhibited Akt phosphorylation while AZD5363 augmented its phosphorylation on Ser473. To add, all compounds inhibited the Akt downstream effectors 4E-BP1 and p70S6 kinase. AZD8835 and AZD5363 sensitized chemoresistant ovarian cancer cells to cisplatin and paclitaxel treatment. Only AZD5363 could inhibit COL11A1 mRNA and promoter activity, which are important factors in Akt regulation and chemoresistance in ovarian cancer. By using a mouse xenograft model, AZD8835 and AZD5363, but not AZD8186, caused a significant reduction in tumor formation. AZD compounds did not change the mRNA expression of BRCA1/BRCA in ovarian cancer cells, but AZD8835 inhibited BRCA1/BRCA2 mRNA expression and p-ERK protein expression in OVCAR-8 cells with the KRAS mutation. This study highlights the importance of PI3K/Akt in ovarian tumor progression and chemoresistance and the potential application of AZD compounds, especially AZD8835 and AZD5363, as therapeutic agents for the treatment of ovarian cancer.
Effect of Sputtered AlN Location on the Growth Mechanism of GaN
(2017-01-01)
Wu, Pei-Yu
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Li, Jhen-Hong
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Hsu, Lung-Hsing
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Huang, Chia-Yen
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Cheng, Yuh-Jen
Patterned sapphire substrates (PSSs) have been used to enhance the performance of GaN-based light-emitting diodes (LEDs). This performance can be further improved by using an ex situ sputtered AlN nucleation layer. This improvement has been attributed to the reduction of the GaN formation on the sidewall of the cone shape pattern. In this study, four kinds of PSS samples were fabricated to investigate the effect of sputtered AlN location on the growth mechanism of GaN in detail. (c) 2017 The Electrochemical Society. All rights reserved.
Enhanced Color-Conversion Efficiency of Hybrid Nanostructured-Cavities InGaN/GaN Light-Emitting Diodes Consisting of Nontoxic InP Quantum Dots
(2017-09-01)
Liu, Che-Yu
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Chen, Tzu-Pei
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Huang, Jhih-Kai
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Lin, Tzu-Neng
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Huang, Chia-Yen
Color-conversion efficiency enhancement of hybrid light-emitting diodes (LEDs) by cadmium-free colloidal quantum dots (QDs) and a novel selective area nanocavities structure has been demonstrated. Combining nanoimprinting and photolithography techniques, nanocavities array can be fabricated at designated locations on the LEDs. The color-conversion efficiency of selective area nanocavities LED can be enhanced by up to 13%. The significant color-conversion efficiency enhancement is attributed to resonance of InP QDs emission in nanocavities and nonradiative energy transfer from LED active layers to InPQDs, which has been investigated and characterized by finite domain time-domain simulation, electroluminescence, and time-resolved photoluminescence measurements. This hybrid nanostructured device, therefore, exhibits a great potential for the applications of multicolor lighting sources and micro-LED.
Growth of GaN on {12(3)over-bar5}-like Facets of Patterned Sapphire Substrate
(2017-01-01)
Wu, Pei-Yu
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Chen, Chien-Chih
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Huang, Chia-Yen
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Kuo, Hao-Chung
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Lin, Kun-Lin
GaN has been grown on wet-etched patterned sapphire substrate (PSS) by metal-organic chemical vapor deposition. It has been found that GaN was initiated not only from bottom c-facet but also from E {12 (3) over bar5} facets of hexagonal patterns/pyramids. In this study, a vacancy-PSS on c-plane sapphire was used to investigate the growth of GaN on the E-like facets (E1 and E2) of distorted pyramids. The results show that the orientation relationship between E1-GaN and sapphire is ((11) over bar2 (6) over bar) GaN // ((1) over bar 10 (2) over bar)(sapphire) and [11 (21) over bar] GaN // [11 (2) over bar0](sapphire). At the same time, that between E2-GaN and sapphire is (01 (14) over bar) GaN // (3 (3) over bar0 (6) over bar) sapphire and [02 (2) over bar1] GaN // [11 (2) over bar0] sapphire. (C) 2017 The Electrochemical Society. All rights reserved.
High-Performance Ultraviolet 385-nm GaN-Based LEDs With Embedded Nanoscale Air Voids Produced Through Atomic Layer Deposition and Al2O3 Passivation
(2016-04)
Liu, Che-Yu
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Huang, Chia-Yen
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Wu, Pei-Yu
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Huang, Jhih-Kai
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Kao, Tsung Sheng
This letter developed the high-performance GaN-based light-emitting diodes (LEDs) for ultraviolet (UV) light emission at 385 nm with the light output power enhanced by up to 52% compared with that of the conventional UV-LEDs. The high-power-efficiency UV-LEDs include sidewall-passivated Al2O3 dielectric nanoscale air voids, which were created using the atomic layer deposition method and act as intermediate media for improving the internal quantum efficiency, reducing threading dislocation, and relaxing strain. The fabricated air void nanostructure also enhanced the light extraction efficiency by similar to 32.7%, resulting in a high-power UV light-emitting device.
High-quality and highly-transparent AlN template on annealed sputter-deposited AlN buffer layer for deep ultra-violet light-emitting diodes
(2017-05-01)
Huang, Chia-Yen
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Wu, Pei-Yu
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Chang, Kai-Shiang
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Lin, Yun-Hsiang
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Peng, Wei-Chih
A high-quality and highly-transparent AlN template was prepared by regrowth on a sputter-deposited AlN buffer layer. The buffer layer was thermally annealed and then underwent AlN regrowth in metalorganic chemical vapor deposition (MOCVD). The peakwidth of (002) and (102) plane x-ray rocking curve was 104 arcsec and 290 arcsec, respectively, indicating a threading dislocation density <5.0 x 10(8) cm(-2). Dislocations were reduced via grain growth and morphological evolution. The absence of carbon impurity source in sputter deposition also resulted in an improved transparency. According to transmission and reflection measurements, the absorption rate of lambda=280 nm emission propagating through the template was less than 6%. (C) 2017 Author(s).
miRTarBase 2016: updates to the experimentally validated miRNA-target interactions database
(2016-01-04)
Chou, Chih-Hung
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Chang, Nai-Wen
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Shrestha, Sirjana
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Hsu, Sheng-Da
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Lin, Yu-Ling
MicroRNAs (miRNAs) are small non-coding RNAs of approximately 22 nucleotides, which negatively regulate the gene expression at the post-transcriptional level. This study describes an update of the miRTarBase (http://miRTarBase.mbc.nctu.edu.tw/) that provides information about experimentally validated miRNA-target interactions (MTIs). The latest update of the miRTarBase expanded it to identify systematically Argonaute-miRNA-RNA interactions from 138 crosslinking and immunoprecipitation sequencing (CLIP-seq) data sets that were generated by 21 independent studies. The database contains 4966 articles, 7439 strongly validated MTIs (using reporter assays or western blots) and 348 007 MTIs from CLIP-seq. The number of MTIs in the miRTarBase has increased around 7-fold since the 2014 miRTarBase update. The miRNA and gene expression profiles from The Cancer Genome Atlas (TCGA) are integrated to provide an effective overview of this exponential growth in the miRNA experimental data. These improvements make the miRTarBase one of the more comprehensively annotated, experimentally validated miRNA-target interactions databases and motivate additional miRNA research efforts.
miRTarBase update 2018: a resource for experimentally validated microRNA-target interactions
(2018-01-04)
Chou, Chih-Hung
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Shrestha, Sirjana
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Yang, Chi-Dung
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Chang, Nai-Wen
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Lin, Yu-Ling
MicroRNAs (miRNAs) are small non-coding RNAs of similar to 22 nucleotides that are involved in negative regulation of mRNA at the post-transcriptional level. Previously, we developed miRTarBase which provides information about experimentally validated miRNA-target interactions (MTIs). Here, we describe an updated database containing 422 517 curated MTIs from 4076 miRNAs and 23 054 target genes collected from over 8500 articles. The number of MTIs curated by strong evidence has increased similar to 1.4-fold since the last update in 2016. In this updated version, target sites validated by reporter assay that are available in the literature can be downloaded. The target site sequence can extract new features for analysis via a machine learning approach which can help to evaluate the performance of miRNA-target prediction tools. Furthermore, different ways of browsing enhance user browsing specific MTIs. With these improvements, miRTarBase serves as more comprehensively annotated, experimentally validated miRNA-target interactions databases in the field of miRNA related research. miRTarBase is available at http://miRTarBase.mbc.nctu.edu.tw/.
Mode-Hopping Phenomena in the InGaN-Based Core-Shell Nanorod Array Collective Lasing
(2018-07-01)
Huang, Chia-Yen
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Tai, Tzu-Ying
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Lin, Jing-Jie
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Chang, Tsu-Chi
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Liu, Che-Yu
A two-dimensional monolithic InGaN-based core-shell it array was excited under a varying temperature. We observed an abrupt dominant mode hopping from 3.29 to 141 eV in the collective lasing as the temperature decreased from T = 240 to 225 K, Photoluminescence under a near-threshold pumping density revealed the splitting of spontaneous emission. between the core and the shell with a decreasing temperature. The bandgap evolution of GaN and InGaN showed opposite trends due to the interaction of temperature effects and bandgap renormalization effects. Theoretical simulation revealed the differences of gain spectra evolution between room lire and to temperature due to the difference the carrier dynamics, In the optically coupled nanorod array, the dominant lasing;mode was not only determined by it structure, but also strongly influenced by external operating conditions. Rattier than singular microcavity lasers the coupled nanorod array demonstrated a broader parameter space for on-chip wavelength manipulation.
Mode-switching phenomena in periodic InGaN-based hexagon microcavity array
(2018-01-01)
Huang, Chia-Yen
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Dai, Tzu-Ying
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Lin, Jing-Jie
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Chang, Tsu-Chi
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Liu, Che-Yu
The lasing behavior of InGaN-based microcavity array was strongly relevant to the excitation area. The stronger rod-to-rod optical interaction between the fundamental axial mode resulted its dominance in the collective lasing behavior.
Monolithic GaN-InGaNCore-shell Lasers in Submicron Scale
(2017-01-01)
Huang, Chia-Yen
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Lin, Jing-Jie
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Chang, Tsu-Chi
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Liu, Che-Yu
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Dai, Tzu-Ying
We demonstrated a GaN-InGaN core-shell nanorod periodic array lasing under room temperature. Optical simulations and photoluminescence measurement revealed optically-coupled whisper gallery modes. The threshold pumping density was 80 kW/cm(2) with a quality factor of 1940.
Phosphorous Diffuser Diverged Blue Laser Diode for Indoor Lighting and Communication
(2015-12-21)
Chi, Yu-Chieh
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Hsieh, Dan-Hua
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Lin, Chung-Yu
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Chen, Hsiang-Yu
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Huang, Chia-Yen
An advanced light-fidelity (Li-Fi) system based on the blue Gallium nitride (GaN) laser diode (LD) with a compact white-light phosphorous diffuser is demonstrated for fusing the indoor whitelighting and visible light communication (VLC). The phosphorous diffuser adhered blue GaN LD broadens luminescent spectrum and diverges beam spot to provide ample functionality including the completeness of Li-Fi feature and the quality of white-lighting. The phosphorous diffuser diverged white-light spot covers a radiant angle up to 120 degrees with CIE coordinates of (0.34, 0.37). On the other hand, the degradation on throughput frequency response of the blue LD is mainly attributed to the selffeedback caused by the reflection from the phosphor-air interface. It represents the current state-ofthe- art performance on carrying 5.2-Gbit/s orthogonal frequency-division multiplexed 16-quadratureamplitude modulation (16-QAM OFDM) data with a bit error rate (BER) of 3.1 x 10(-3) over a 60-cm freespace link. This work aims to explore the plausibility of the phosphorous diffuser diverged blue GaN LD for future hybrid white-lighting and VLC systems.
Pilot Study to Establish a Novel Five-Gene Biomarker Panel for Predicting Lymph Node Metastasis in Patients With Early Stage Endometrial Cancer
(2020-01-21)
Huang, Chia-Yen
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Liao, Kuang-Wen
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Chou, Chih-Hung
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Shrestha, Sirjana
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Yang, Chi-Dung
Introduction: In the United States and Europe, endometrial endometrioid carcinoma (EEC) is the most prevalent gynecologic malignancy. Lymph node metastasis (LNM) is the key determinant of the prognosis and treatment of EEC. A biomarker that predicts LNM in patients with EEC would be beneficial, enabling individualized treatment. Current preoperative assessment of LNM in EEC is not sufficiently accurate to predict LNM and prevent overtreatment. This pilot study established a biomarker signature for the prediction of LNM in early stage EEC. Methods: We performed RNA sequencing in 24 clinically early stage (T1) EEC tumors (lymph nodes positive and negative in 6 and 18, respectively) from Cathay General Hospital and analyzed the RNA sequencing data of 289 patients with EEC from The Cancer Genome Atlas (lymph node positive and negative in 33 and 256, respectively). We analyzed clinical data including tumor grade, depth of tumor invasion, and age to construct a sequencing-based prediction model using machine learning. For validation, we used another independent cohort of early stage EEC samples (n = 72) and performed quantitative real-time polymerase chain reaction (qRT-PCR). Finally, a PCR-based prediction model and risk score formula were established. Results: Eight genes (ASRGL1, ESR1, EYA2, MSX1, RHEX, SCGB2A1, SOX17, and STX18) plus one clinical parameter (depth of myometrial invasion) were identified for use in a sequencing-based prediction model. After qRT-PCR validation, five genes (ASRGL1, RHEX, SCGB2A1, SOX17, and STX18) were identified as predictive biomarkers. Receiver operating characteristic curve analysis revealed that these five genes can predict LNM. Combined use of these five genes resulted in higher diagnostic accuracy than use of any single gene, with an area under the curve of 0.898, sensitivity of 88.9%, and specificity of 84.1%. The accuracy, negative, and positive predictive values were 84.7, 98.1, and 44.4%, respectively. Conclusion: We developed a five-gene biomarker panel associated with LNM in early stage EEC. These five genes may represent novel targets for further mechanistic study. Our results, after corroboration by a prospective study, may have useful clinical implications and prevent unnecessary elective lymph node dissection while not adversely affecting the outcome of treatment for early stage EEC.
Polypoid endometriosis - A rare entity of endometriosis mimicking ovarian cancer
(2019-05-01)
Tsai, Cleo
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Huang, Shih-Hung
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Huang, Chia-Yen
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生物科技學系
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Department of Biological Science and Technology
Objective: To report a rare case of polypoid endometriosis with initial impression of ovarian cancer and review the published literature about this disease. Case report: A 23-year-old female presented with sudden onset of acute lower abdominal pain. Image studies revealed an irregular shaped, heterogeneous mass at the cul-de-sac, but without ascites or enlargement of pelvic or paraaortic lymph nodes. Blood tests showed an elevated CA-125 value (1317 U/ ml). Resection of the mass was performed by laparotomy and the frozen section and final pathology both revealed polypoid endometriosis. Post-operative gonadotropin-releasing hormone agonist was given for 6 months followed by oral contraceptives. She remained disease free 3 years after operation. Conclusion: Polypoid endometriosis is an uncommon and distinctive variant of endometriosis. Gynecologists should be aware of this rare form of a commonly benign disease to avoid excessive resection in younger patients of childbearing age. (C) 2019 Taiwan Association of Obstetrics & Gynecology. Publishing services by Elsevier B.V.
Suppression of "volcano" morphology and parasitic defect luminescence in AlGaN-based deep-UV light-emitting diode epitaxy
(2019-06-01)
Huang, Chia-Yen
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Liu, Tsung-Yen
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Huang, Shih-Ming
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Chang, Kai-Hsiang
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Tai, Tsu-Ying
In this study we overcame several critical growth issues related to epitaxy in AlGaN deep-ultraviolet lightemitting diodes. Irregular-shaped pits with dislocation clusters were observed in micron-thick layers of AlGaN on AlN. The strain-induced morphology and defects were suppressed after the insertion of superlattice transition layers between the AlGaN and AlN layers. The defect luminescence in the active region was governed by radiative recombination through the oxygen shallow donors and deep acceptors related to III-vacancies. After optimization of the growth conditions and a decrease in growth interruption, the intensity of the parasitic blueband emission was suppressed by up to 95%. Energy dispersive spectroscopy suggests that the desorption of gallium from the surface is the major source of the III-vacancies.
The Effect of Phosphor Concentration on Laser-Based White Light Communication System
(2016)
Hsieh, Dan-Hua
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Wu, Tsai-Chen
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Chi, Yu-Chieh
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Chen, Yi-Rou
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Huang, Chia-Yen
Laser-based white light communication system with free-standing phosphor film is demonstrated, and the effect of phosphor concentration on white light quality and data quality is discussed to achieve the highest data rate of 6.8 Gbit/s.
The origin and mitigation of volcano-like morphologies in micron-thick AlGaN/AlN heteroepitaxy
(2017-08-14)
Huang, Chia-Yen
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Chang, Kai-Shiang
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Huang, Cheng-Yao
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Lin, Yun-Hsiang
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Peng, Wei-Chih
We investigated the origin of morphological instability in 2 mu m thick Al0.6Ga0.4N/AlN heteroepitaxy. The primary morphology was driven by the residual epitaxial strain, forming hill-like morphologies via surface diffusion. The secondary morphology was driven by the interaction between the primary morphology and dislocation clusters in the epitaxial layers. The difference in the local growth rate yields volcano-like morphologies centering on deep pits. Insertion of multi-stack superlattice transition layers between AlGaN and GaN effectively suppressed the secondary morphologies by simultaneously pre-relaxing the template and filtering treading dislocations. Published by AIP Publishing.