157 results on '"Chen, Yi-Yung"'
Search Results
152. Secondary optical design for safety light curtains
- Author
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Hsu, Yu-Hsiang, Chen, Yi-Yung, and Whang, Allen Jong-Woei
- Abstract
LED has many advantages that will replace traditional light sources. In this article, we design a convergence lens and use a LED light source with ± 30° half-power angle. The lens can convergence light source and make it become parallel light. The goal to achieve high directivity can be applied to wireless sensors. According to the simulation results, compared to the LED with dome lens that has ± 0.6° half-power angle, the LED use our design's lens has ± 0.34° half-power angle. In the same transmission distance, the LED with our design's lens has more than 200 times received energy.
- Published
- 2012
- Full Text
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153. Non-axisymmetrical freeform design for short LED street lamp
- Author
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Jen, Ching-Hsuan, Chen, Yi-Yung, Whang, Allen Jong-Woei, and Lu, Ming-Jun
- Abstract
Based on energy savings trend, LED has been developing as the main force of the future lighting, especially the road lighting. For controlling the intensity distribution of LED, the concept of freeform design has been proposed in many articles with transmission or reflection components but mainly focus on axial symmetrical types or dual axial symmetrical types. We, in this paper, design a non-axisymmetrical freeform system applying in a short LED street lamp whose dimension is 10cm (W) x 10cm (L) x 7cm (H) that has an advantage, easy maintaining. For coordinate transformation and simplifying the non- axisymmetrical system, we create two virtual surfaces and design the slope of each discrete point on the freeform surface to control the light path between the two virtual surfaces and avoid the total internal reflection. The short street lamp has four LEDs to light 3m square and each LED light a triangle area. According to the simulation results, the uniformity of illumination is 1:3 and the optical efficiency is more than 80% that meet the legal requirements of street lamp. In short, to reduce manufacturing and maintenance costs, the proposed design is appropriate to use in the actual lighting on the road and to replace the traditional street lamps.
- Published
- 2011
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154. Associations between first-trimester screening biomarkers and maternal characteristics with gestational diabetes mellitus in Chinese women.
- Author
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Lu YT, Chen CP, Sun FJ, Chen YY, Wang LK, and Chen CY
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- Humans, Female, Pregnancy, Adult, Retrospective Studies, China epidemiology, Placenta Growth Factor blood, Chorionic Gonadotropin, beta Subunit, Human blood, Prenatal Diagnosis methods, Pre-Eclampsia epidemiology, Pre-Eclampsia diagnosis, Pre-Eclampsia blood, East Asian People, Diabetes, Gestational diagnosis, Diabetes, Gestational epidemiology, Diabetes, Gestational blood, Pregnancy Trimester, First blood, Biomarkers blood, Pregnancy-Associated Plasma Protein-A metabolism, Pregnancy-Associated Plasma Protein-A analysis
- Abstract
Background: Gestational diabetes mellitus (GDM) can result in adverse maternal and neonatal outcomes. Predicting those at high risk of GDM and early interventions can reduce the development of GDM. The aim of this study was to examine the associations between first-trimester prenatal screening biomarkers and maternal characteristics in relation to GDM in Chinese women., Methods: We conducted a retrospective cohort study of singleton pregnant women who received first-trimester aneuploidy and preeclampsia screening between January 2019 and May 2021. First-trimester prenatal screening biomarkers, including pregnancy-associated plasma protein A (PAPP-A), free beta-human chorionic gonadotropin, and placental growth factor (PLGF), along with maternal characteristics, were collected for analysis in relation to GDM. Receiver operating characteristic (ROC) curve and logistic regression analyses were used to evaluate variables associated with GDM., Results: Of the 1452 pregnant women enrolled, 96 developed GDM. PAPP-A (5.01 vs. 5.73 IU/L, P < 0.001) and PLGF (39.88 vs. 41.81 pg/mL, P = 0.044) were significantly lower in the GDM group than in the non-GDM group. The area under the ROC curve of combined maternal characteristics and biomarkers was 0.73 (95% confidence interval [CI] 0.68-0.79, P < 0.001). The formula for predicting GDM was as follows: P = 1/[1 + exp (-8.148 + 0.057 x age + 0.011 x pregestational body mass index + 1.752 x previous GDM history + 0.95 x previous preeclampsia history + 0.756 x family history of diabetes + 0.025 x chronic hypertension + 0.036 x mean arterial pressure - 0.09 x PAPP-A - 0.001 x PLGF)]. Logistic regression analysis revealed that higher pregestational body mass index (adjusted odds ratio [aOR] 1.03, 95% CI 1.01 - 1.06, P = 0.012), previous GDM history (aOR 9.97, 95% CI 3.92 - 25.37, P < 0.001), family history of diabetes (aOR 2.36, 95% CI 1.39 - 4.02, P = 0.001), higher mean arterial pressure (aOR 1.17, 95% CI 1.07 - 1.27, P < 0.001), and lower PAPP-A level (aOR 0.91, 95% CI 0.83 - 1.00, P = 0.040) were independently associated with the development of GDM. The Hosmer-Lemeshow test demonstrated that the model exhibited an excellent discrimination ability (chi-square = 3.089, df = 8, P = 0.929)., Conclusion: Downregulation of first-trimester PAPP-A and PLGF was associated with the development of GDM. Combining first-trimester biomarkers with maternal characteristics could be valuable for predicting the risk of GDM., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Lu, Chen, Sun, Chen, Wang and Chen.)
- Published
- 2024
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155. Perinatal imaging findings of a fetus with Pfeiffer syndrome and a heterozygous c.1019A>G, p.Tyr340Cys (Y340C) mutation in FGFR2 presenting a cloverleaf skull, craniosynostosis and short limbs on prenatal ultrasound mimicking thanatophoric dysplasia type II.
- Author
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Chen CP, Huang JP, Huang KS, Chen YY, Wu FT, Pan YT, Chiu CL, and Wang W
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- Humans, Female, Pregnancy, Adult, Mutation, Diagnosis, Differential, Magnetic Resonance Imaging, Heterozygote, Infant, Newborn, Skull diagnostic imaging, Skull abnormalities, Skull embryology, Acrocephalosyndactylia genetics, Acrocephalosyndactylia diagnostic imaging, Acrocephalosyndactylia diagnosis, Ultrasonography, Prenatal, Receptor, Fibroblast Growth Factor, Type 2 genetics, Craniosynostoses genetics, Craniosynostoses diagnostic imaging, Craniosynostoses diagnosis, Thanatophoric Dysplasia genetics, Thanatophoric Dysplasia diagnostic imaging
- Abstract
Objective: We present perinatal imaging findings of a fetus with Pfeiffer syndrome and a heterozygous c.1019A>G, p.Tyr340Cys (Y340C) mutation in FGFR2 presenting a cloverleaf skull, craniosynostosis and short limbs on prenatal ultrasound mimicking thanatophoric dysplasia type II (TD2)., Case Report: A 37-year-old, gravida 2, para 1, woman underwent amniocentesis at 17 weeks of gestation because of advanced maternal age. Amniocentesis revealed a karyotype of 46,XY. However, craniofacial anomaly was found on prenatal ultrasound at 21 weeks of gestation, which showed a cloverleaf skull with severe craniosynostosis and relatively short straight long bones. Fetal magnetic resonance imaging (MRI) analysis at 22 weeks of gestation showed a cloverleaf skull, proptosis and relatively shallowing of the sylvian fissures. Prenatal ultrasound at 24 weeks of gestation showed a fetus with a cloverleaf skull with a biparietal diameter (BPD) of 6.16 cm (equivalent to 24 weeks), an abdominal circumference (AC) of 18.89 cm (equivalent to 24 weeks) and a femur length (FL) of 3.65 cm (equivalent to 21 weeks). A tentative diagnosis of TD2 was made. The pregnancy was subsequently terminated, and a 928-g malformed fetus was delivered with severe craniosynostosis, proptosis, midface retrusion, a cloverleaf skull, broad thumbs and broad big toes. The broad thumbs were medially deviated. Whole body X-ray showed a cloverleaf skull and straight long bones. However, molecular analysis of FGFR3 on the fetus revealed no mutation in the target regions. Subsequent whole exome sequencing (WES) on the DNA extracted from umbilical cord revealed a heterozygous c.1019A>G, p.Tyr340Cys (Y340C) mutation in the FGFR2 gene., Conclusion: Fetuses with a Y340C mutation in FGFR2 may present a cloverleaf skull on prenatal ultrasound, and WES is useful for a rapid differential diagnosis of Pfeiffer syndrome from TD2 under such a circumstance., (Copyright © 2024. Published by Elsevier B.V.)
- Published
- 2024
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156. 1,25-Dihydroxy vitamin D 3 stimulates system A amino acid transport in primary human trophoblast cells.
- Author
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Chen YY, Powell TL, and Jansson T
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- Cells, Cultured, Cholecalciferol metabolism, Female, Fetal Development drug effects, Gestational Age, Humans, Placenta drug effects, Placenta metabolism, Pregnancy, RNA, Small Interfering metabolism, Receptors, Calcitriol metabolism, Signal Transduction drug effects, TOR Serine-Threonine Kinases metabolism, Trophoblasts metabolism, Vitamin D pharmacology, Amino Acid Transport System A metabolism, Amino Acids metabolism, Trophoblasts drug effects, Vitamin D analogs & derivatives
- Abstract
Vitamin D deficiency during pregnancy is linked to adverse perinatal outcomes such as small for gestational age infants. Recent evidence suggests that changes in placental amino acid transport contribute to altered fetal growth. We tested the hypothesis that 1,25-dihydroxy vitamin D
3 increases the gene expression of System A and L amino acid transporter isoforms and stimulates placental amino acid transport activity in cultured primary human trophoblast cells mediated by mTOR signaling. Treatment with 1,25-dihydroxy vitamin D3 significantly increased mRNA expression of the System A isoform SNAT2 and System A activity, but had no effect on System L and did not affect mTOR signaling. siRNA silencing of the vitamin D receptor prevented 1,25-dihydroxy vitamin D3 -stimulated System A transport. In conclusion, 1,25-dihydroxy vitamin D3 regulates System A activity through increased mRNA expression of SNAT2 transporters. Effects on placental amino acid transport may be the mechanism underlying the association between maternal vitamin D status and fetal growth., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)- Published
- 2017
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157. Angiogenesis in differentiated placental multipotent mesenchymal stromal cells is dependent on integrin alpha5beta1.
- Author
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Lee MY, Huang JP, Chen YY, Aplin JD, Wu YH, Chen CY, Chen PC, and Chen CP
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- Animals, Cell Adhesion, Cell Differentiation, Chick Embryo, Extracellular Matrix metabolism, Female, Flow Cytometry methods, Humans, Placenta metabolism, Pregnancy, Reverse Transcriptase Polymerase Chain Reaction, Stromal Cells cytology, von Willebrand Factor metabolism, Integrin alpha5beta1 metabolism, Mesenchymal Stem Cells cytology, Neovascularization, Pathologic
- Abstract
Human placental multipotent mesenchymal stromal cells (hPMSCs) can be isolated from term placenta, but their angiogenic ability and the regulatory pathways involved are not known. hPMSCs were shown to express integrins alpha(v), alpha(4), alpha(5), beta(1), beta(3), and beta(5) and could be induced to differentiate into cells expressing endothelial markers. Increases in cell surface integrins alpha(5) and beta(1), but not alpha(4), alpha(v)beta(3), or alpha(v)beta(5), accompanied endothelial differentiation. Vascular endothelial growth factor-A augmented the effect of fibronectin in enhancing adhesion and migration of differentiated hPMSC through integrin alpha(5)beta(1), but not alpha(v)beta(3) or alpha(v)beta(5). Formation of capillary-like structures in vitro from differentiated cells was inhibited by pre-treatment with function-blocking antibodies to integrins alpha(5) and beta(1). When hPMSCs were seeded onto chick chorioallantoic membranes (CAM), human von Willebrand factor-positive cells were observed to engraft in the chick endothelium. CAMs transplanted with differentiated hPMSCs had a greater number of vessels containing human cells and more incorporated cells per vessel compared to CAMs transplanted with undifferentiated hPMSCs, and overall angiogenesis was enhanced more by the differentiated cells. Function-blocking antibodies to integrins alpha(5) and beta(1) inhibited angiogenesis in the CAM assay. These results suggest that differentiated hPMSCs may contribute to blood vessel formation, and this activity depends on integrin alpha(5)beta(1).
- Published
- 2009
- Full Text
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