2006 European Conference on Optical Communications, 2006
This investigation experimentally demonstrates tunable slow light in a 1550 nm distributed feedba... more This investigation experimentally demonstrates tunable slow light in a 1550 nm distributed feedback Laser. Tunable optical group delays of 30 ps for 10 GHz are achieved by varying the bias current.
Conference on Lasers and Electro-Optics/International Quantum Electronics Conference, 2009
Distinctive indium-tin-oxide nanorods are demonstrated using glancing-angle deposition. The nanos... more Distinctive indium-tin-oxide nanorods are demonstrated using glancing-angle deposition. The nanostructured material exhibit enhanced transmission and is employed to enhance the light-output-power of GaN/InGaN vertical-injection light emitting diodes by 20% at an injection current of 350 mA.
Asia Communications and Photonics Conference and Exhibition, 2009
Two types of GaN-based blue surface emitting lasers recently developed were presented. One was a ... more Two types of GaN-based blue surface emitting lasers recently developed were presented. One was a vertical cavity surface emitting laser which achieved laser action under CW current injection at 77K. Another is a photonic crystal surface emitting laser operated at room temperature. Detailed fabrication techniques and performance characteristics are described.
Background: To compare the neocortical amyloid loads among cognitively normal (CN), amnestic mild... more Background: To compare the neocortical amyloid loads among cognitively normal (CN), amnestic mild cognitive impairment (aMCI), and Alzheimer's disease (AD) subjects with [ 18 F]AV-45 positron emission tomography (PET). Materials and Methods: [ 18 F]AV-45 PET was performed in 11 CN, 13 aMCI, and 12 AD subjects to compare the cerebral cortex-to-whole cerebellum standard uptake value ratios (SUVRs) of global and individual volumes of interest (VOIs) cerebral cortex. The correlation between global cortical [ 18 F]AV-45 SUVRs and Mini-Mental State Examination (MMSE) scores was analyzed. Results: The global cortical [ 18 F]AV-45 SUVRs were significantly different among the CN (1.0860.08), aMCI (1.2760.06), and AD groups (1.3460.13) (p = 0.0003) with amyloidosis positivity rates of 9%, 62%, and 92% in the three groups respectively. Compared to CN subjects, AD subjects had higher SUVRs in the global cortical, precuneus, frontal, parietal, occipital, temporal, and posterior cingulate areas; while aMCI subjects had higher values in the global cortical, precuneus, frontal, occipital and posterior cingulate areas. There were negative correlations of MMSE scores with SUVRs in the global cortical, precuneus, frontal, parietal, occipital, temporal, posterior cingulate and anterior cingulate areas on a combined subject pool of the three groups after age and education attainment adjustment. Conclusions: Amyloid deposition occurs relatively early in precuneus, frontal and posterior cingulate in aMCI subjects. Higher [ 18 F]AV-45 accumulation is present in parietal, occipital and temporal gyri in AD subjects compared to the aMCI group. Significant correlation between MMSE scores and [ 18 F]AV-45 SUVRs can be observed among CN, aMCI and AD subjects.
Mammalian genomes are replete with retrotransposable elements, including endogenous retroviruses.... more Mammalian genomes are replete with retrotransposable elements, including endogenous retroviruses. DNA methyltransferase 3-like (DNMT3L) is an epigenetic regulator expressed in prospermatogonia, growing oocytes, and embryonic stem (ES) cells. Here, we demonstrate that DNMT3L enhances the interaction of repressive epigenetic modifiers, including histone deacetylase 1 (HDAC1), SET domain, bifurcated 1 (SETDB1), DNA methyltransferase 3A (DNMT3A), and tripartite motif-containing protein 28 (TRIM28; also known as TIF1 and KAP1) in ES cells and orchestrates retroviral silencing activity with TRIM28 through mechanisms including, but not limited to, de novo DNA methylation. Ectopic expression of DNMT3L in somatic cells causes methylation-independent retroviral silencing activity by recruitment of the TRIM28/HDAC1/SETDB1/DNMT3A/DNMT3L complex to newly integrated Moloney murine leukemia virus (Mo-MuLV) proviral DNA. Concurrent with this recruitment, we also observed the accumulation of histone H3 lysine 9 trimethylation (H3K9me3) and heterochromatin protein 1 gamma (HP1␥), as well as reduced H3K9 and H3K27 acetylation at Mo-MuLV proviral sequences. Ectopic expression of DNMT3L in late-passage mouse embryonic fibroblasts (MEFs) recruited cytoplasmically localized HDAC1 to the nucleus. The formation of this epigenetic modifying complex requires interaction of DNMT3L with DNMT3A as well as with histone H3. In fetal testes at embryonic day 17.5, endogenous DNMT3L also enhanced the binding among TRIM28, DNMT3A, SETDB1, and HDAC1. We propose that DNMT3L may be involved in initiating a cascade of repressive epigenetic modifications by assisting in the preparation of a chromatin context that further attracts DNMT3A-DNMT3L binding and installs longer-term DNA methylation marks at newly integrated retroviruses. IMPORTANCE Almost half of the mammalian genome is composed of endogenous retroviruses and other retrotransposable elements that threaten genomic integrity. These elements are usually subject to epigenetic silencing. We discovered that two epigenetic regulators that lack enzymatic activity, DNA methyltransferase 3-like (DNMT3L) and tripartite motif-containing protein 28 (TRIM28), collaborate with each other to impose retroviral silencing. In addition to modulating de novo DNA methylation, we found that by interacting with TRIM28, DNMT3L can attract various enzymes to form a DNMT3L-induced repressive complex to remove active marks and add repressive marks to histone proteins. Collectively, these results reveal a novel and pivotal function of DNMT3L in shaping the chromatin modifications necessary for retroviral and retrotransposon silencing.
Recent studies indicate that neonatal spermatogonial stem cells (SSCs) possess pluripotency. Howe... more Recent studies indicate that neonatal spermatogonial stem cells (SSCs) possess pluripotency. However, the mechanisms that regulate the pluripotent differentiation capacity of SSCs remain unclear. Here, we describe a new method to clonally derive pluripotent SSCs from neonatal mouse testis. By coculturing with testicular stromal cells, SSCs can be maintained and expanded in serum-free conditions. Unlike endogenous SSCs, these in vitro expanded SSCs showed strong alkaline phosphatase (AP) activity and displayed characteristics of embryonic stem cells and primordial germ cells, which were therefore designated as AP ؉ germline stem cells (AP ؉ GSCs). The pluripotency of AP ؉ GSCs was confirmed by in vitro differentiation toward hepatic and neuronal lineages and formation of embryonic chimeras after injection into blastocysts. Further investigation revealed that insulin-like growth factor-1 (IGF-1) secreted from Leydig cells was a key factor involved in maintaining the pluripotency of AP ؉ GSCs. The blockage of IGF-1 receptor phosphorylation and its downstream PI3K pathway by PPP or LY294002 dramatically reduced their AP activity and expression of pluripotent genes, such as Oct-4, Blimp1, and Nanog. In conclusion, the present study demonstrated that IGF-1 secreted by testicular Leydig cells plays an important role in maintaining the pluripotency of SSCs in culture, which provides an insight into the molecular mechanism underlying germ cell pluripotency.
We have designed, fabricated and measured the electroluminescence of InGaN-based green light-emit... more We have designed, fabricated and measured the electroluminescence of InGaN-based green light-emitting diodes (LEDs) having composite omni-directional reflectors (ODRs) deposited on their backside. The composite ODR is composed of a stack of two individual ODRs, each of which is made of alternating layers of TiO 2 and SiO 2 with a thickness ratio that gives the largest possible 1D photonic bandgap. The lattice constants of these individual ODRs are chosen so that the effective bandgap of the resulting ODR completely covers the emission spectrum of the LEDs. The effective bandgap of our ODR extends from 498 nm to 548 nm. At a driving current of 300 mA, and with the LED emission peak at about 525 nm and a FWHM of about 35 nm, the light output powers of the LED with the composite ODR and the LED with a conventional Ti/Al metal reflector are found to be 52.9 mW and 40.7 mW, respectively. This 30% light extraction enhancement can be attributed to our composite ODR which has a higher reflectance, a lower optical absorption and a wider reflection angle compared with the Ti/Al reflector.
An InGaAs submonolayer (SML) quantum dot photonic crystal vertical-cavity surface-emitting laser ... more An InGaAs submonolayer (SML) quantum dot photonic crystal vertical-cavity surface-emitting laser (QD PhC-VCSEL) for fibre-optic applications is demonstrated for the first time. The active region of the device contains three InGaAs SML QD layers. Each of the InGaAs SML QD layers is formed by alternate deposition of InAs (<1 ML) and GaAs. Single-fundamental-mode CW output power of 3.8 mW at 28 mA has been achieved in the 990 nm range, with a threshold current of 0.9 mA. A side-mode suppression ratio (SMSR) larger than 35 dB has been observed over the entire current operating range.
Optically modulated internal strain has been observed in InGaN quantum dots (QDs) deposited on Si... more Optically modulated internal strain has been observed in InGaN quantum dots (QDs) deposited on SiN x nano masks. The modulated internal strain can induce a number of intriguing effects, including the change of refractive index and the redshift of InGaN A 1 (LO) phonon. The underlying mechanism can be well accounted for in terms of the variation of internal strain through the converse piezoelectric effect arising from the screening of the internal electric field due to spatial separation of photoexcited electrons and holes. Our results point out a convenient way for the fine tuning of physical properties in nitride-based semiconductor nanostructures, which is very important for high quality optoelectronic devices.
To investigate the prevalence and genetic characteristics of myotonic dystrophy type 1 (DM1) in T... more To investigate the prevalence and genetic characteristics of myotonic dystrophy type 1 (DM1) in Taiwan, DM-suspected patients and their families identified during the period of 1990–2001 had their clinical records reevaluated and the CTG repeat sizes at the DM1 locus examined. A total of 96 subjects belonging to 26 families were identified as DM1 patients, which gave a minimal disease prevalence of 0.46/100,000 inhabitants. Clinical anticipation was frequently observed in affected families, even in some parent-child pairs with transmission contraction of the CTG repeat size. The inverse correlation between age at onset and CTG repeat length was significant only in patients with small expansions. In addition, a DM1 carrier with a childhood-onset son was found to have CTG length heterogeneity in the range of 40–50, indicating that premutation alleles could be unstable during gametogenesis as well as in somatic tissues. Our data demonstrated that DM1 is a rare disease in Taiwan and sho...
We report the utilization of an selective As +-implanted underlying layer and regrowth method to ... more We report the utilization of an selective As +-implanted underlying layer and regrowth method to enhance and control the wet thermal oxidation rate for 850 nm oxide-confined VCSEL. The oxidation rate of the As +-implanted device showed a four-fold increase over the non-implanted one at the As + dosage of 1 × 10 16 cm −3 and the oxidation temperature of 400 • C. The 50 side-by-side As +-implanted oxideconfined VCSELs fabricated using the method achieved very uniform performance with a deviation in threshold current of I th ∼ 0.2 mA and slope-efficiency of S.E. ∼ 3%. Finally, we accumulated life test data for oxide-confined VCSELs with As +-implanted underlying layer up to 1000 h at 80 o C/15 mA.
In this study, a high-performance GaN-based light-emitting diode (LED) was achieved using a nanoc... more In this study, a high-performance GaN-based light-emitting diode (LED) was achieved using a nanocolumn patterned sapphire substrate (NCPSS) with low-pressure metal-organic chemical vapor deposition (LP-MOCVD). The surface roughness was evaluated by atomic force microscopy (AFM). The mechanisms of carrier localization in the GaN-based LED fabricated on NCPSS were discussed referring to the results obtained from the power-dependent photoluminescence measurements. Moreover, from the transmission electron microscopy (TEM) image, the threading dislocation densities (TDDs) through the GaN-based LED fabricated on NCPSS were found to be about 10 times lower than those fabricated on planar substrates. Finally, the internal quantum efficiency (IQE) of the GaN-based LED fabricated on NCPSS was as high as 48% at 30 mW, corresponding to a current of 20 mA, which is higher than that of a GaN-based LED fabricated on a planar sapphire substrate by 8%. The use of NCPSS is suggested to be effective f...
Introduction and hypothesis Some lower urinary tract dysfunction (LUTD) subtypes may have similar... more Introduction and hypothesis Some lower urinary tract dysfunction (LUTD) subtypes may have similar symptoms. This study aimed to investigate the feasibility of using the International Prostate Symptom Score (IPSS) to evaluate lower urinary tract symptoms (LUTS) in women. Methods All consecutive women with non-stress urinary incontinence LUTS who visited the urologic clinics for treatment were prospectively enrolled. LUTS include urinary storage, voiding, and post-micturition symptoms. All enrolled patients were requested to complete the Overactive Bladder Symptom Score (OABSS) and the modified Indevus Urgency Severity Scale (IUSS) questionnaires as well undergo uroflowmetry and post-void residual testing. A videourodynamic study was also performed, if indicated, for LUTD. Results A total of 222 women were enrolled, including 60 with overactive bladder (OAB) dry, 42 with OAB wet, 78 with bladder oversensitivity, and 42 with voiding dysfunction. A significantly higher IPSS voiding to storage subscore ratio (IPSS-V/S) and IPSS voiding score were found in the voiding dysfunction group. IPSS-V/S was found to have the highest area under the receiver-operating characteristic curve for predicting voiding LUTD than other noninvasive methods, and an IPSS-V/S of ≥1.33 had the best predictive value for female voiding LUTD with a high negative predictive value (97.4 %). In addition, significantly higher IPSS storage subscore (IPSS-S) values were found in the OAB wet subgroup, and the IPSS-S was well correlated with the OABSS and IUSS. Conclusions The IPSS can be used to evaluate female LUTD. IPSS-V/S may provide an initial guide for the treatment of voiding dysfunction in women. In addition, IPSS-S may be used for evaluating storage LUTD in women.
IEEE Journal of Selected Topics in Quantum Electronics, 2011
The current-voltage (I-V) characteristics of the InGaN nanorod light-emitting diode (LED) are eva... more The current-voltage (I-V) characteristics of the InGaN nanorod light-emitting diode (LED) are evaluated using nanoprobes installed on a field-emission scanning electron microscope. The saturated current of the InGaN nanorod LED (I O = 2 × 10 −9 A) is found to be orders of magnitude higher than those obtained by downscaling a conventional InGaN LED to a chip size of 300 × 300 μm 2 (I O 1 = 1 × 10 −25 A; I O 2 = 1 × 10 −14 A). This observation is explained by the fact that the nanorod LED is associated with enhanced tunneling of injected carriers and, therefore, reduction of the defect-assisted leakage current and the diffusion-recombination process that normally occurs in InGaN LEDs.
Mitochondrial function and the effect of oocyte aging on parthenogenetic activation of mouse oocy... more Mitochondrial function and the effect of oocyte aging on parthenogenetic activation of mouse oocytes. K.
SummaryBackground Genetic heritability and maternal atopy have been correlated to antenatal IgE p... more SummaryBackground Genetic heritability and maternal atopy have been correlated to antenatal IgE production, but very few studies have studied gene–maternal atopy interaction on antenatal IgE production. This study investigated the interaction of CTLA‐4 polymorphism with prenatal factors on the elevation of cord blood IgE (CBIgE).Methods Pregnant women were antenatally recruited for collection of prenatal environmental factors by a questionnaire. Umbilical cord blood samples were collected for CBIgE detection by fluorescence‐linked enzyme assay and CTLA‐4 polymorphism measurement by restriction fragment length polymorphism.Results A total of 1104 pregnant women initially participated in this cohort study, and 898 of them completed cord blood collection. 21.4% of the newborns had elevation of CBIgE (0.5 kU/L). The CTLA‐4+49A allele (P=0.021), maternal atopy (P<0.001) and gender (P=0.034), but not the CTLA‐4+49G allele, −318C allele, −318T allele, parental smoking or paternal atopy,...
2006 European Conference on Optical Communications, 2006
This investigation experimentally demonstrates tunable slow light in a 1550 nm distributed feedba... more This investigation experimentally demonstrates tunable slow light in a 1550 nm distributed feedback Laser. Tunable optical group delays of 30 ps for 10 GHz are achieved by varying the bias current.
Conference on Lasers and Electro-Optics/International Quantum Electronics Conference, 2009
Distinctive indium-tin-oxide nanorods are demonstrated using glancing-angle deposition. The nanos... more Distinctive indium-tin-oxide nanorods are demonstrated using glancing-angle deposition. The nanostructured material exhibit enhanced transmission and is employed to enhance the light-output-power of GaN/InGaN vertical-injection light emitting diodes by 20% at an injection current of 350 mA.
Asia Communications and Photonics Conference and Exhibition, 2009
Two types of GaN-based blue surface emitting lasers recently developed were presented. One was a ... more Two types of GaN-based blue surface emitting lasers recently developed were presented. One was a vertical cavity surface emitting laser which achieved laser action under CW current injection at 77K. Another is a photonic crystal surface emitting laser operated at room temperature. Detailed fabrication techniques and performance characteristics are described.
Background: To compare the neocortical amyloid loads among cognitively normal (CN), amnestic mild... more Background: To compare the neocortical amyloid loads among cognitively normal (CN), amnestic mild cognitive impairment (aMCI), and Alzheimer's disease (AD) subjects with [ 18 F]AV-45 positron emission tomography (PET). Materials and Methods: [ 18 F]AV-45 PET was performed in 11 CN, 13 aMCI, and 12 AD subjects to compare the cerebral cortex-to-whole cerebellum standard uptake value ratios (SUVRs) of global and individual volumes of interest (VOIs) cerebral cortex. The correlation between global cortical [ 18 F]AV-45 SUVRs and Mini-Mental State Examination (MMSE) scores was analyzed. Results: The global cortical [ 18 F]AV-45 SUVRs were significantly different among the CN (1.0860.08), aMCI (1.2760.06), and AD groups (1.3460.13) (p = 0.0003) with amyloidosis positivity rates of 9%, 62%, and 92% in the three groups respectively. Compared to CN subjects, AD subjects had higher SUVRs in the global cortical, precuneus, frontal, parietal, occipital, temporal, and posterior cingulate areas; while aMCI subjects had higher values in the global cortical, precuneus, frontal, occipital and posterior cingulate areas. There were negative correlations of MMSE scores with SUVRs in the global cortical, precuneus, frontal, parietal, occipital, temporal, posterior cingulate and anterior cingulate areas on a combined subject pool of the three groups after age and education attainment adjustment. Conclusions: Amyloid deposition occurs relatively early in precuneus, frontal and posterior cingulate in aMCI subjects. Higher [ 18 F]AV-45 accumulation is present in parietal, occipital and temporal gyri in AD subjects compared to the aMCI group. Significant correlation between MMSE scores and [ 18 F]AV-45 SUVRs can be observed among CN, aMCI and AD subjects.
Mammalian genomes are replete with retrotransposable elements, including endogenous retroviruses.... more Mammalian genomes are replete with retrotransposable elements, including endogenous retroviruses. DNA methyltransferase 3-like (DNMT3L) is an epigenetic regulator expressed in prospermatogonia, growing oocytes, and embryonic stem (ES) cells. Here, we demonstrate that DNMT3L enhances the interaction of repressive epigenetic modifiers, including histone deacetylase 1 (HDAC1), SET domain, bifurcated 1 (SETDB1), DNA methyltransferase 3A (DNMT3A), and tripartite motif-containing protein 28 (TRIM28; also known as TIF1 and KAP1) in ES cells and orchestrates retroviral silencing activity with TRIM28 through mechanisms including, but not limited to, de novo DNA methylation. Ectopic expression of DNMT3L in somatic cells causes methylation-independent retroviral silencing activity by recruitment of the TRIM28/HDAC1/SETDB1/DNMT3A/DNMT3L complex to newly integrated Moloney murine leukemia virus (Mo-MuLV) proviral DNA. Concurrent with this recruitment, we also observed the accumulation of histone H3 lysine 9 trimethylation (H3K9me3) and heterochromatin protein 1 gamma (HP1␥), as well as reduced H3K9 and H3K27 acetylation at Mo-MuLV proviral sequences. Ectopic expression of DNMT3L in late-passage mouse embryonic fibroblasts (MEFs) recruited cytoplasmically localized HDAC1 to the nucleus. The formation of this epigenetic modifying complex requires interaction of DNMT3L with DNMT3A as well as with histone H3. In fetal testes at embryonic day 17.5, endogenous DNMT3L also enhanced the binding among TRIM28, DNMT3A, SETDB1, and HDAC1. We propose that DNMT3L may be involved in initiating a cascade of repressive epigenetic modifications by assisting in the preparation of a chromatin context that further attracts DNMT3A-DNMT3L binding and installs longer-term DNA methylation marks at newly integrated retroviruses. IMPORTANCE Almost half of the mammalian genome is composed of endogenous retroviruses and other retrotransposable elements that threaten genomic integrity. These elements are usually subject to epigenetic silencing. We discovered that two epigenetic regulators that lack enzymatic activity, DNA methyltransferase 3-like (DNMT3L) and tripartite motif-containing protein 28 (TRIM28), collaborate with each other to impose retroviral silencing. In addition to modulating de novo DNA methylation, we found that by interacting with TRIM28, DNMT3L can attract various enzymes to form a DNMT3L-induced repressive complex to remove active marks and add repressive marks to histone proteins. Collectively, these results reveal a novel and pivotal function of DNMT3L in shaping the chromatin modifications necessary for retroviral and retrotransposon silencing.
Recent studies indicate that neonatal spermatogonial stem cells (SSCs) possess pluripotency. Howe... more Recent studies indicate that neonatal spermatogonial stem cells (SSCs) possess pluripotency. However, the mechanisms that regulate the pluripotent differentiation capacity of SSCs remain unclear. Here, we describe a new method to clonally derive pluripotent SSCs from neonatal mouse testis. By coculturing with testicular stromal cells, SSCs can be maintained and expanded in serum-free conditions. Unlike endogenous SSCs, these in vitro expanded SSCs showed strong alkaline phosphatase (AP) activity and displayed characteristics of embryonic stem cells and primordial germ cells, which were therefore designated as AP ؉ germline stem cells (AP ؉ GSCs). The pluripotency of AP ؉ GSCs was confirmed by in vitro differentiation toward hepatic and neuronal lineages and formation of embryonic chimeras after injection into blastocysts. Further investigation revealed that insulin-like growth factor-1 (IGF-1) secreted from Leydig cells was a key factor involved in maintaining the pluripotency of AP ؉ GSCs. The blockage of IGF-1 receptor phosphorylation and its downstream PI3K pathway by PPP or LY294002 dramatically reduced their AP activity and expression of pluripotent genes, such as Oct-4, Blimp1, and Nanog. In conclusion, the present study demonstrated that IGF-1 secreted by testicular Leydig cells plays an important role in maintaining the pluripotency of SSCs in culture, which provides an insight into the molecular mechanism underlying germ cell pluripotency.
We have designed, fabricated and measured the electroluminescence of InGaN-based green light-emit... more We have designed, fabricated and measured the electroluminescence of InGaN-based green light-emitting diodes (LEDs) having composite omni-directional reflectors (ODRs) deposited on their backside. The composite ODR is composed of a stack of two individual ODRs, each of which is made of alternating layers of TiO 2 and SiO 2 with a thickness ratio that gives the largest possible 1D photonic bandgap. The lattice constants of these individual ODRs are chosen so that the effective bandgap of the resulting ODR completely covers the emission spectrum of the LEDs. The effective bandgap of our ODR extends from 498 nm to 548 nm. At a driving current of 300 mA, and with the LED emission peak at about 525 nm and a FWHM of about 35 nm, the light output powers of the LED with the composite ODR and the LED with a conventional Ti/Al metal reflector are found to be 52.9 mW and 40.7 mW, respectively. This 30% light extraction enhancement can be attributed to our composite ODR which has a higher reflectance, a lower optical absorption and a wider reflection angle compared with the Ti/Al reflector.
An InGaAs submonolayer (SML) quantum dot photonic crystal vertical-cavity surface-emitting laser ... more An InGaAs submonolayer (SML) quantum dot photonic crystal vertical-cavity surface-emitting laser (QD PhC-VCSEL) for fibre-optic applications is demonstrated for the first time. The active region of the device contains three InGaAs SML QD layers. Each of the InGaAs SML QD layers is formed by alternate deposition of InAs (<1 ML) and GaAs. Single-fundamental-mode CW output power of 3.8 mW at 28 mA has been achieved in the 990 nm range, with a threshold current of 0.9 mA. A side-mode suppression ratio (SMSR) larger than 35 dB has been observed over the entire current operating range.
Optically modulated internal strain has been observed in InGaN quantum dots (QDs) deposited on Si... more Optically modulated internal strain has been observed in InGaN quantum dots (QDs) deposited on SiN x nano masks. The modulated internal strain can induce a number of intriguing effects, including the change of refractive index and the redshift of InGaN A 1 (LO) phonon. The underlying mechanism can be well accounted for in terms of the variation of internal strain through the converse piezoelectric effect arising from the screening of the internal electric field due to spatial separation of photoexcited electrons and holes. Our results point out a convenient way for the fine tuning of physical properties in nitride-based semiconductor nanostructures, which is very important for high quality optoelectronic devices.
To investigate the prevalence and genetic characteristics of myotonic dystrophy type 1 (DM1) in T... more To investigate the prevalence and genetic characteristics of myotonic dystrophy type 1 (DM1) in Taiwan, DM-suspected patients and their families identified during the period of 1990–2001 had their clinical records reevaluated and the CTG repeat sizes at the DM1 locus examined. A total of 96 subjects belonging to 26 families were identified as DM1 patients, which gave a minimal disease prevalence of 0.46/100,000 inhabitants. Clinical anticipation was frequently observed in affected families, even in some parent-child pairs with transmission contraction of the CTG repeat size. The inverse correlation between age at onset and CTG repeat length was significant only in patients with small expansions. In addition, a DM1 carrier with a childhood-onset son was found to have CTG length heterogeneity in the range of 40–50, indicating that premutation alleles could be unstable during gametogenesis as well as in somatic tissues. Our data demonstrated that DM1 is a rare disease in Taiwan and sho...
We report the utilization of an selective As +-implanted underlying layer and regrowth method to ... more We report the utilization of an selective As +-implanted underlying layer and regrowth method to enhance and control the wet thermal oxidation rate for 850 nm oxide-confined VCSEL. The oxidation rate of the As +-implanted device showed a four-fold increase over the non-implanted one at the As + dosage of 1 × 10 16 cm −3 and the oxidation temperature of 400 • C. The 50 side-by-side As +-implanted oxideconfined VCSELs fabricated using the method achieved very uniform performance with a deviation in threshold current of I th ∼ 0.2 mA and slope-efficiency of S.E. ∼ 3%. Finally, we accumulated life test data for oxide-confined VCSELs with As +-implanted underlying layer up to 1000 h at 80 o C/15 mA.
In this study, a high-performance GaN-based light-emitting diode (LED) was achieved using a nanoc... more In this study, a high-performance GaN-based light-emitting diode (LED) was achieved using a nanocolumn patterned sapphire substrate (NCPSS) with low-pressure metal-organic chemical vapor deposition (LP-MOCVD). The surface roughness was evaluated by atomic force microscopy (AFM). The mechanisms of carrier localization in the GaN-based LED fabricated on NCPSS were discussed referring to the results obtained from the power-dependent photoluminescence measurements. Moreover, from the transmission electron microscopy (TEM) image, the threading dislocation densities (TDDs) through the GaN-based LED fabricated on NCPSS were found to be about 10 times lower than those fabricated on planar substrates. Finally, the internal quantum efficiency (IQE) of the GaN-based LED fabricated on NCPSS was as high as 48% at 30 mW, corresponding to a current of 20 mA, which is higher than that of a GaN-based LED fabricated on a planar sapphire substrate by 8%. The use of NCPSS is suggested to be effective f...
Introduction and hypothesis Some lower urinary tract dysfunction (LUTD) subtypes may have similar... more Introduction and hypothesis Some lower urinary tract dysfunction (LUTD) subtypes may have similar symptoms. This study aimed to investigate the feasibility of using the International Prostate Symptom Score (IPSS) to evaluate lower urinary tract symptoms (LUTS) in women. Methods All consecutive women with non-stress urinary incontinence LUTS who visited the urologic clinics for treatment were prospectively enrolled. LUTS include urinary storage, voiding, and post-micturition symptoms. All enrolled patients were requested to complete the Overactive Bladder Symptom Score (OABSS) and the modified Indevus Urgency Severity Scale (IUSS) questionnaires as well undergo uroflowmetry and post-void residual testing. A videourodynamic study was also performed, if indicated, for LUTD. Results A total of 222 women were enrolled, including 60 with overactive bladder (OAB) dry, 42 with OAB wet, 78 with bladder oversensitivity, and 42 with voiding dysfunction. A significantly higher IPSS voiding to storage subscore ratio (IPSS-V/S) and IPSS voiding score were found in the voiding dysfunction group. IPSS-V/S was found to have the highest area under the receiver-operating characteristic curve for predicting voiding LUTD than other noninvasive methods, and an IPSS-V/S of ≥1.33 had the best predictive value for female voiding LUTD with a high negative predictive value (97.4 %). In addition, significantly higher IPSS storage subscore (IPSS-S) values were found in the OAB wet subgroup, and the IPSS-S was well correlated with the OABSS and IUSS. Conclusions The IPSS can be used to evaluate female LUTD. IPSS-V/S may provide an initial guide for the treatment of voiding dysfunction in women. In addition, IPSS-S may be used for evaluating storage LUTD in women.
IEEE Journal of Selected Topics in Quantum Electronics, 2011
The current-voltage (I-V) characteristics of the InGaN nanorod light-emitting diode (LED) are eva... more The current-voltage (I-V) characteristics of the InGaN nanorod light-emitting diode (LED) are evaluated using nanoprobes installed on a field-emission scanning electron microscope. The saturated current of the InGaN nanorod LED (I O = 2 × 10 −9 A) is found to be orders of magnitude higher than those obtained by downscaling a conventional InGaN LED to a chip size of 300 × 300 μm 2 (I O 1 = 1 × 10 −25 A; I O 2 = 1 × 10 −14 A). This observation is explained by the fact that the nanorod LED is associated with enhanced tunneling of injected carriers and, therefore, reduction of the defect-assisted leakage current and the diffusion-recombination process that normally occurs in InGaN LEDs.
Mitochondrial function and the effect of oocyte aging on parthenogenetic activation of mouse oocy... more Mitochondrial function and the effect of oocyte aging on parthenogenetic activation of mouse oocytes. K.
SummaryBackground Genetic heritability and maternal atopy have been correlated to antenatal IgE p... more SummaryBackground Genetic heritability and maternal atopy have been correlated to antenatal IgE production, but very few studies have studied gene–maternal atopy interaction on antenatal IgE production. This study investigated the interaction of CTLA‐4 polymorphism with prenatal factors on the elevation of cord blood IgE (CBIgE).Methods Pregnant women were antenatally recruited for collection of prenatal environmental factors by a questionnaire. Umbilical cord blood samples were collected for CBIgE detection by fluorescence‐linked enzyme assay and CTLA‐4 polymorphism measurement by restriction fragment length polymorphism.Results A total of 1104 pregnant women initially participated in this cohort study, and 898 of them completed cord blood collection. 21.4% of the newborns had elevation of CBIgE (0.5 kU/L). The CTLA‐4+49A allele (P=0.021), maternal atopy (P<0.001) and gender (P=0.034), but not the CTLA‐4+49G allele, −318C allele, −318T allele, parental smoking or paternal atopy,...
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Papers by Prof. HC Kuo