141 results on '"Chen, Po-Yu"'
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2. Comparison of dexmedetomidine versus propofol sedation on microcirculation and organ injuries in critically ill surgical patients: A randomized controlled pilot study.
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Chen, Po-Yu, Huang, Hsing-Hao, Chan, Wing-Sum, Liu, Chih-Min, Wu, Tsung-Ta, Chen, Jyun-Han, Chao, Anne, Tien, Yu-Wen, Chiu, Ching-Tang, and Yeh, Yu-Chang
- Abstract
Recent studies have shown that dexmedetomidine may improve microcirculation and prevent organ failure. However, most evidence was obtained from experimental animals and patients receiving cardiac surgery with cardiopulmonary bypass. This study aimed to investigate the effect of dexmedetomidine on microcirculation and organ injuries in critically ill general surgical patients.In this prospective randomized trial, patients admitted to the surgical intensive care unit after general surgery were enrolled and randomly allocated to the dexmedetomidine or propofol groups. Patients received continuous dexmedetomidine or propofol infusions to meet their requirement of sedation according to their grouping. At each time point, sublingual microcirculation images were obtained using the incident dark field video microscope.Overall, 60 patients finished the trial and were analyzed. Microcirculation parameters did not differ significantly between two groups. Heart rate at 4 h after ICU admission and mean arterial pressures at 12 h and 24 h after ICU admission were lower in the dexmedetomidine group than in the propofol group. At 24 h, serum aspartate aminotransferase (41 (25–118) vs 86 (34–129) U/L,
p = 0.035) and alanine aminotransferase (50 (26–160) vs 68 (35–172) U/L,p = 0.019) levels were significantly lower in the dexmedetomidine group than in the propofol group.Microcirculation parameters did not differ significantly between the dexmedetomidine and propofol groups. At 24 h after ICU admission, serum liver enzyme levels were lower in patients receiving dexmedetomidine as compared to propofol. [ABSTRACT FROM AUTHOR]- Published
- 2024
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3. Higher orexin-A levels are associated with treatment response to clozapine in patients with schizophrenia: A cross-sectional study.
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Chen, Po-Yu, Chiu, Chih-Chiang, Chang, Chin-Kuo, Lu, Mong-Liang, Huang, Cho-Yin, Chen, Chun-Hsin, and Huang, Ming-Chyi
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OREXINS , *PSYCHIATRIC rating scales , *CLOZAPINE , *PEOPLE with schizophrenia , *CROSS-sectional method , *VISUAL memory - Abstract
Background: Clozapine is the primary antipsychotic (APD) for treatment-resistant schizophrenia (TRS). However, only 40% of patients with TRS respond to clozapine, constituting a subgroup of clozapine-resistant patients. Recently, the neuropeptide orexin-A was shown to be involved in the pathophysiology of schizophrenia. This study evaluated the association of orexin-A levels with the clozapine response in patients with TRS. Methods: We recruited 199 patients with schizophrenia, including 37 APD-free and 162 clozapine-treated patients. Clozapine-treated patients were divided into clozapine-responsive (n = 100) and clozapine-resistant (n = 62) groups based on whether they had achieved psychotic remission defined by the 18-item Brief Psychiatric Rating Scale (BPRS-18). We compared blood orexin-A levels among the three groups and performed regression analysis to determine the association of orexin-A level with treatment response in clozapine-treated patients. We also explored the correlation between orexin-A levels and cognitive function, assessed using the CogState Schizophrenia Battery. Results: Clozapine-responsive patients had higher orexin-A levels than clozapine-resistant and APD-free patients. Orexin-A level was the only factor significantly associated with treatment response after adjustment. Orexin-A levels were negatively correlated with BPRS-18 full scale and positive, negative, and general symptoms subscale scores. We also observed a positive correlation between orexin-A levels and verbal memory, visual learning and memory, and working memory function. Conclusions: This cross-sectional study showed that higher levels of orexin-A are associated with treatment response to clozapine in patients with TRS. Future prospective studies examining changes in orexin-A level following clozapine treatment and the potential benefit of augmenting orexin-A signaling are warranted. [ABSTRACT FROM AUTHOR]
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- 2024
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4. Prevalence and 3-year incidence of physical illnesses after schizophrenia diagnosis: Comparison with general population.
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Chen, Yi-Lung, Chen, Po-Yu, Pan, Chun-Hung, Chen, Pao-Huan, Su, Sheng-Shiang, Tsai, Shang-Ying, Chen, Chiao-Chicy, and Kuo, Chian-Jue
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CEREBROVASCULAR disease , *LYMPHATIC diseases , *VEIN diseases , *SCHIZOPHRENIA , *MYOCARDIAL ischemia , *CORONARY disease - Abstract
People with schizophrenia are at a greater risk of poor physical health than the general population. This study investigated the annual incidence of physical illnesses after a new schizophrenia diagnosis, which has rarely been investigated in the literature. The authors collected data from Taiwan's National Health Insurance Research Database from January 1, 1996, to December 31, 2013, and enrolled 1910 patients with newly diagnosed schizophrenia cases aged 10–40 years and 7640 age- and sex-matched controls from the general population. They estimated the 1-year prevalence and annual incidence rate ratio (IRR) of specified physical diseases across 3 years in the schizophrenia group compared with the controls. Several physical illnesses were prevalent within 1 year of schizophrenia diagnosis. Regarding incident physical illnesses, patients had a moderate to strong risk of numerous physical illnesses (IRR > 3.0: ischemic heart disease, cerebrovascular disease, diabetes mellitus, and cancer; IRR 1.8–3.0: other forms of heart disease, vein and lymphatic diseases, pneumonia, chronic hepatic disease, and ulcer disease) within the first year after schizophrenia diagnosis. The IRRs of most physical illnesses declined over 3 years, except for that of cerebrovascular disease, which significantly increased (IRR > 3.0) over the 3 years after schizophrenia diagnosis. Cerebrovascular disease had a significant incidence risk (IRR > 3) persistently across the 3 years. Various comorbid physical illnesses can occur in the early stages of schizophrenia. Clinicians should consider these vulnerabilities to physical illnesses during the evaluation of patients with newly diagnosed schizophrenia by attempting to prevent, screen for, and manage them. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Incidence of and risk factors for alcohol dependence in bipolar disorder: A population-based cohort and nested case–control study.
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Hsu, Haw-En, Chen, Po-Yu, Chang, Hu-Ming, Pan, Chun-Hung, Su, Sheng-Shiang, Tsai, Shang-Ying, Chen, Chiao-Chicy, and Kuo, Chian-Jue
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ALCOHOLISM risk factors , *DRUG addiction risk factors , *ALCOHOLISM , *AGE distribution , *MULTIVARIATE analysis , *CASE-control method , *DISEASE incidence , *RISK assessment , *SEX distribution , *MEDICAL care use , *DESCRIPTIVE statistics , *RESEARCH funding , *BIPOLAR disorder , *LONGITUDINAL method , *COMORBIDITY - Abstract
Objectives: Although alcohol dependence is highly prevalent in patients with bipolar disorder, the causal relationship is not yet well-established. This study estimated the incidence of alcohol dependence in a nationwide bipolar disorder cohort and examined risk factors for alcohol dependence. Methods: Patients aged 15–65 years with consistent bipolar disorder who had their first psychiatric admission between 1999 and 2012 (n = 21,791) were enrolled from the National Health Insurance Research Database in Taiwan. We calculated the adjusted incidence rate ratio of alcohol dependence in the bipolar cohort relative to the general population after stratification by age and sex. In the nested case–control study, we included patients with incident alcohol dependence as cases and four age- and sex-matched controls for each case to analyze health care utilization, comorbidities and concomitant medications between them. Results: We identified 1261 patients with bipolar disorder with incident alcohol dependence. Relative to the general population, the adjusted incidence rate ratio of alcohol dependence was 9.20 in the bipolar cohort. All adjusted incidence rate ratios were high across all age subgroups. Cases had higher psychiatric and nonpsychiatric health care utilization than did controls. Multivariate analysis revealed that cases tended to have cardiovascular disease, diabetes mellitus, chronic hepatic disease, pneumonia and delirium before alcohol dependence diagnosis. Cases had higher psychiatric comorbidities, namely drug-induced mental disorders, anxiety disorder, personality disorder, adjustment disorder and sleep disorder. Conclusion: The bipolar cohort had a higher incidence of alcohol dependence. We identified specific groups with a high risk of alcohol dependence. Additional strategies for early detection, treatment and intervention for alcohol dependence should be developed. [ABSTRACT FROM AUTHOR]
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- 2023
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6. Investigation on the Anisotropic Wetting Properties of Water Droplets on Bio-Inspired Groove Structures Fabricated by 3D Printing and Surface Modifications.
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Mai, Ngoc Phuong Uyen and Chen, Po-Yu
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ANISOTROPIC crystals , *THREE-dimensional printing , *FABRICATION (Manufacturing) , *TRANSPLANTATION of organs, tissues, etc. , *SPIDER silk - Abstract
The self-driving structure to orientate the water movement has attracted considerable attention. Inspired by the wedgelike structures of biological materials in nature, such as spider silks and cactus spines, anisotropic spreading can be realized by combining Laplace pressure gradient and hydrophilic surface. In this study, a series of groove patterns were fabricated by a combination of 3D printing and surface modification. PLA pattern was modified by the atmospheric pressure plasma, followed by grafting with hydrolyzed APTES. This work reports the anisotropic transport of water droplets on a series of designed dart-shaped groove patterns with specific angles in the main arrow and tail regions. This structure can induce capillary force to regulate droplets from the main cone to two wedgelike, whereas the droplets are hindered toward the opposite side is oat the vicinity of the groove's tail. By means of the experiment, the mechanism of water transport in this pattern was revealed. This study can contribute a potential approach to manipulate and apply anisotropic wetting in many fields. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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7. Enhancement of the Modulation Response of Quantum-Dot-Based Down-Converted Light through Surface Plasmon Coupling.
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Yang, Shaobo, Chen, Po-Yu, Ni, Chia-Chun, Chen, Jun-Chen, Li, Zong-Han, Kuo, Yang, Yang, Chih-Chung, Hsu, Ta-Cheng, and Lee, Chi-Ling
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FLUORESCENCE resonance energy transfer , *LIGHT emitting diodes , *SEMICONDUCTOR nanocrystals - Abstract
In this paper, we first elaborate on the effects of surface plasmon (SP) coupling on the modulation responses of the emission of a light-emitting diode (LED) and its down-converted lights through colloidal quantum dots (QDs). The results of our past efforts for this subject are briefly discussed. The discussions lay the foundation for the presentation of the new experimental data of such down-converted lights in this paper. In particular, the enhancement of the modulation bandwidth (MB) of a QD-based converted light through SP coupling is demonstrated. By linking green-emitting QDs (GQDs) and/or red-emitting QDs (RQDs) with synthesized Ag nano-plates via surface modifications and placing them on a blue-emitting LED, the MBs of the converted green and red emissions are significantly increased through the induced SP coupling of the Ag nano-plates. When both GQD and RQD exist and are closely spaced in a sample, the energy transfer processes of emission-reabsorption and Förster resonance energy transfer from GQD into RQD occur, leading to the increase (decrease) in the MB of green (red) light. With SP coupling, the MB of a mixed light is significantly enhanced. [ABSTRACT FROM AUTHOR]
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- 2022
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8. Mechanical properties of additively manufactured multi-material stiff-soft interfaces: Guidelines to manufacture complex interface composites with tunable properties.
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Ghimire, Ashish and Chen, Po-Yu
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NANOINDENTATION tests , *ELASTIC modulus , *THREE-dimensional printing - Abstract
[Display omitted] • The TSIC model facilitates the design of complex interface composites with stiff and compliant materials. • Control of the tensile and shear interface thickness allows tuning of the composites' stiffness and strength, respectively. • Fracture analysis reveals non-columnar fractures as a key to enhancing interface hardening in TSICs. • UV curing during printing results in a gradient elastic modulus at stiff-soft interfaces, enhancing strength compared to non-UV-cured samples. The rapid growth of polyjet additive manufacturing has propelled the 3D printing of multi-material polymer composites toward unprecedented applications. Interfaces in such composites play a paramount role in determining mechanical performance. This study delves into the crucial role of interfaces, employing VeroWhite and Agilus30Black materials to scrutinize the tensile and shear properties of stiff-soft interfaces. By applying these layers strategically, composites with multi-oriented interfaces were created, revealing the impact of soft material thickness and orientation on stiffness and strength. We identified columnar and non-columnar fracture mechanisms, shedding light on their correlation with interface hardening. Nanoindentation tests unveil the local interface properties, emphasizing the gradient change in elastic modulus when printed on the x -axis and the sharp drop on the z -axis. These findings offer valuable insights into material selection and interface optimization, providing a roadmap for achieving tailored mechanical properties in complex interface composites. [ABSTRACT FROM AUTHOR]
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- 2024
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9. Comparative efficacy of brolucizumab, half-dose photodynamic therapy, and aflibercept in managing chronic central serous chorioretinopathy.
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Huang, Yu-Te, Tien, Peng-Tai, Chen, Po-Yu, Yang, Chi-Lan, and Chen, San-Ni
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PHOTODYNAMIC therapy , *AFLIBERCEPT , *CHOROID , *INTRAVITREAL injections , *VISUAL acuity - Abstract
Purpose: To compare the efficacy of brolucizumab, half-dose PDT, and aflibercept in treating chronic central serous chorioretinopathy (CSC). Methods: A retrospective cohort study with chronic CSC patients who underwent intravitreal injection of one shot of brolucizumab or aflibercept in the first 3 months, followed by pro re nata regimens or a single session of half-dose PDT, was retrospectively reviewed. The primary outcome measure was the proportion of eyes that achieved complete absorption of retinal fluid without requiring any rescue treatment. Secondary outcomes included changes in best-corrected visual acuity (BCVA), central retinal thickness (CRT), and central choroidal thickness (CCT). Results: A total of 54 consecutive patients were included in this study with 18 patients in each group. At months 1 and 2, the brolucizumab group exhibited the highest rate of complete retinal fluid resolution (61% and 77%), followed by the half-dose PDT group (56% and 72%), and lowest in the aflibercept group (28% and 33%), with statistically significant differences noted at month 2 (P = 0.012). The brolucizumab group also demonstrated the most significant reduction in CCT at months 1 and 2 among the three groups (P = 0.007 and 0.001). Recurrence of retinal fluid in the brolucizumab groups was predominantly observed at month 3. Conversely, the half-dose PDT group exhibited the most favorable anatomical results starting from month 3. Notably, mild vitritis was observed in one case from the brolucizumab group. Conclusions: Single injection of brolucizumab demonstrates trends of faster regression of persistent residual retinal fluid, greater CCT and CRT decline, and matched BCVA compared to half-dose PDT in the short term. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Fractal nature analysis in porous structured bio-ceramics.
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Mitić, Vojislav V., Chen, Po-Yu, Chou, Yueh-Ying, Ilić, Ivana D., Marković, Bojana, and Lazović, Goran
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FRACTAL analysis , *FRACTAL dimensions , *PRINT materials , *NUCLEATION , *GEOMETRIC shapes , *POROSITY - Abstract
Hydroxyapatite scaffold is a type of bio-ceramic. Its cellular design has similarities with the morphologies in nature. Therefore, it is very important to control the structure, especially the porosity, as one of the main features for bio-ceramics applications. According to some literature, freeze casting can form the shape of dendrites and remain a foam structure after ice sublimation. Ice nucleation became more heterogeneous with the aid of printing materials during freeze casting. This procedure can even improve the issue of crack formation. In this paper, we studied the mechanical properties of hydroxyapatite scaffold. We also analyzed the porosity by fractal nature characterization, and successfully reconstructed pore shape, which is important for predicting ceramic morphology. We applied SEM analysis on bio-ceramic samples, at four different magnifications for the same pore structure. This is important for fractal analysis and pores reconstruction. We calculated the fractal dimensions based on measurements. In this way, we completed the fractal characterization of porosity and confirmed possibilities for successful porous shapes reconstruction. In this paper, we confirmed, for the first time, that fractal nature can be successfully applied in the area of porous bio-ceramics. [ABSTRACT FROM AUTHOR]
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- 2021
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11. Engineering large and geometrically controlled vascularized nerve tissue in collagen hydrogels to restore large-sized volumetric muscle loss.
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Wei, Shih-Yen, Chen, Po-Yu, Hsieh, Chia-Chang, Chen, Yu-Shan, Chen, Tzu-Hsuan, Yu, Yu-Shan, Tsai, Min-Chun, Xie, Ren-Hao, Chen, Guan-Yu, Yin, Gung-Chian, Melero-Martin, Juan M., and Chen, Ying-Chieh
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NERVE tissue , *HYDROGELS , *COLLAGEN , *HEMATOPOIESIS , *BLOOD vessels , *ENGINEERING - Abstract
Developing scalable vascularized and innervated tissue is a critical challenge for the successful clinical application of tissue-engineered constructs. Collagen hydrogels are extensively utilized in cell-mediated vascular network formation because of their naturally excellent biological properties. However, the substantial increase in hydrogel contraction induced by populated cells limits their long-term use. Previous studies attempted to mitigate this issue by concentrating collagen pre-polymer solutions or synthesizing covalently crosslinked collagen hydrogels. However, these methods only partially reduce hydrogel contraction while hindering blood vessel formation within the hydrogels. To address this challenge, we introduced additional support in the form of a supportive spacer to counteract the contraction forces of populated cells and prevent hydrogel contraction. This approach was found to promote cell spreading, resist hydrogel contraction, control hydrogel/tissue geometry, and even facilitate the engineering of functional blood vessels and host nerve growth in just one week. Subsequently, implanting these engineered tissues into muscle defect sites resulted in timely anastomosis with the host vasculature, leading to enhanced myogenesis, increased muscle innervation, and the restoration of injured muscle functionality. Overall, this innovative strategy expands the applicability of collagen hydrogels in fabricating large vascularized nerve tissue constructs for repairing volumetric muscle loss (∼63 %) and restoring muscle function. [Display omitted] [ABSTRACT FROM AUTHOR]
- Published
- 2023
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12. Experimental investigation of thin film stress by Stoney's formula.
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Chen, Po-Yu, Wang, Wei-Chung, and Wu, Yen-Ting
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THIN films , *PSYCHOLOGICAL stress , *APPLIED mechanics , *PHOTOELASTICITY , *MAXIMA & minima , *INTERFEROMETERS - Abstract
• The correctness and accuracy of Stoney's formula was experimentally investigated. • Stoney's formula is not proper for finding larger non-equibiaxial thin film stress. • The use of a single curvature in Stoney's formula is too much over-simplified. • 19.57% stress biaxiality increase makes 654.5% up of maximum and minimum difference. In this paper, the radii of curvature and the stresses of transparent photoelastic circular disks without/with coating of the silicon dioxide (SiO 2) thin film with three different thicknesses were respectively measured by Fizeau interferometer and photoelasticity. In all past research work, thin film stresses (TFSs) of only two directions were measured and the difference between them was determined. However, the real maximum TFS can never be found. In this paper, TFSs of a number of directions of the substrate were measured so that both the magnitude and direction of principal stresses can be calculated. The calculated principal stress difference (PSD) by Stoney's formula and the equivalent TFS calculated by the enhanced exposure theory of photoelasticity (EEToP) are called PSD-STONEY and ETFS-EEToP, respectively. By comparing the results of the PSD-STONEY and PSD-ETFS-EEToP, the maximum and minimum differences are 28.35 MPa (215.4%) and 9.520 MPa (28.55%), respectively. Furthermore, with an increase about 19.57% of stress biaxiality of TFS, the increase of maximum and minimum difference between the results of Stoney's formula and photoelasticity is 654.5%. Based on the experimental findings of this paper, Stoney's formula is not suitable for calculating larger non-equibiaxial thin film stress. The assessment method of TFS developed in this paper for Stoney's formula with an independent measurement of substrate stress by photoelasticity is novel and can be used to verify other forms of Stoney's formula. Part of this work has been presented at the 2016 SEM 2016 Annual Conference & Exposition on Experimental and Applied Mechanics —Orlando, 6 Jun–9 Jun 2016 with the title "Wei-Chung Wang, et al., Investigation of Non-equibiaxial thin film stress by Using Stoney Formula". [ABSTRACT FROM AUTHOR]
- Published
- 2019
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13. INCORPORATING THE BUDDHA'S THREEFOLD TRAINING WITH MANAGEMENT SCIENCE THEORIES.
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Chen, Miao-Sheng and Chen, Po-Yu
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MANAGEMENT science , *SCIENTIFIC development , *OCULAR dominance , *BUDDHISM , *HERMENEUTICS - Abstract
The acceleration of the evolution of economic culture through scientific development affords the opportunity to re-examine cross-domain dialogue and research in Buddhism and other disciplines. The concepts of threefold training in Buddhism (i.e. precepts, samadhi, and wisdom) were used as data items to generate data values and thereby convey the semantic nature of these terms. A systems analysis approach that can adequately incorporate hermeneutics into management science was employed to present the research topic. This study illustrates the relationship between a management activity (i.e. its effectiveness and efficiency, and the mechanism used) and a Buddhist activity (i.e. threefold training). This relationship was used to establish a body- and mind-transcending system comprising two subsystems: a service subsystem that adopts the perspective of management science by emphasising the 'way of things' and a submission subsystem that adopts a Buddhist perspective by stressing the 'way of people'. The main finding of this study is that the two subsystems are characterised by identical Buddhist concepts. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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14. Investigation of electrochemical properties of bio-inspired SiOx/PI multilayered thin film anode for lithium ion batteries.
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Ye, Guan-Ting, Chen, Po-Yu, and Duh, Jenq-Gong
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ELECTROCHEMICAL analysis , *SILICA , *MULTILAYERED thin films , *LITHIUM-ion batteries , *ANODES - Abstract
The organic-inorganic multilayer thin film composed of SiO x (nonstoichiometric silicon suboxides) and PI (polyimide) has been synthesized by a hybrid sputtering system combining reactive RF sputtering and pulsed laser deposition. SiO x /PI thin films were deposited on a copper foil to investigate its electrochemical properties. The chemical composition of as-deposited SiO x /PI coatings was measured by a FE-EPMA. The overall multilayered structure was observed by a Scanning Electron Microscopy. The SiO x /PI multilayer thin film anode with proper architecture control exhibits higher columbic efficiency during 1st charge/discharge cycle and better capacity retention as compared to pure SiO x thin film anode. The fracture toughness of SiO x /PI multilayer thin film anode is measured via nanoindentation and be compared to the pure SiO x thin film anode. The results show that the multilayer structure reveals a higher fracture toughness, which leads to a better structure stability during the charge/discharge cycling. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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15. Analysis of critical factors for social games based on extended technology acceptance model: a DEMATEL approach.
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Chang, Chia-Chi and Chen, Po-Yu
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CUSTOMER satisfaction , *INTERNET , *LEISURE , *MULTIVARIATE analysis , *SOCIAL norms , *SOCIALIZATION , *SURVEYS , *VIDEO games , *STRUCTURAL equation modeling - Abstract
In recent years, social games such as 'Farmville' and 'Pokémon Go' have become a major game type in the gaming industry. This study examines the importance of different factors in social games using the Technology Acceptance Model (TAM) and DEMATEL. The result shows 'social norm' as the most important factor overall. It is also found that 'pleasure' and 'sociability' are the most important aspects in 'perceived enjoyment'. Regarding key aspects in each factor, 'flow experience' is crucial in 'perceived attractiveness', 'game fairness' largely influential in 'social norm', and 'reputation of platform and service provider' a decisive aspect in 'platform service and corporate image'. These findings and analyses are apt references for social game providers to improve their services. [ABSTRACT FROM AUTHOR]
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- 2018
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16. Melaleuca alternifolia Induces Heme Oxygenase-1 Expression in Murine RAW264.7 Cells through Activation of the Nrf2-ARE Pathway.
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Lee, Shih-Yu, Chen, Po-Yu, Lin, Jung-Chun, Kirkby, Nicholas S., Ou, Ching-Huei, and Chang, Tsu-Chung
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ANTI-inflammatory agents , *THERAPEUTIC use of essential oils , *ANIMAL experimentation , *CELL lines , *CYTOKINES , *GENE expression , *MACROPHAGES , *POLYMERASE chain reaction , *RESEARCH funding , *RODENTS , *STATISTICS , *DATA analysis , *DATA analysis software , *ONE-way analysis of variance ,THERAPEUTIC use of plant extracts - Abstract
Melaleuca alternifolia concentrate (MAC) is the refined essential oil of the Australian native plant Melaleuca alternifolia. MAC has been reported to suppress the production of pro-inflammatory cytokines in both murine RAW264.7 macrophages and human monocytes stimulated with lipopolysaccharide (LPS). However, the mechanisms involved in this effect remain unclear. This study aims to delineate the molecular mechanisms that drive the anti-inflammatory activity of MAC and its active component, terpinen-4-ol, in macrophages. The effects of MAC on RAW264.7 cells were studied using western blotting, real-time PCR, an electrophoretic mobility shift assay (EMSA), and NF-B luciferase reporter assays. Our results showed that MAC significantly increased both the mRNA and protein levels of heme oxygenase-1 (HO-1) via p38 and JNK MAPK activation. In addition, we showed that MAC significantly increased the activation and nuclear translocation of NF-E2-related factor 2 (Nrf2), a key transcription factor regulating HO-1 induction. MAC was also associated with significant inhibition of iNOS expression, NO production, and NF-B activation. HO-1 was required for these anti-inflammatory effects as tin protoporphyrin IX (SnPPIX), an HO-1 inhibitor, abolished the effects of MAC on LPS-induced iNOS, NO, and NF-B activation. Our results indicate that MAC induces HO-1 expression in murine macrophages via the p38 MAPK and JNK pathways and that this induction is required for its anti-inflammatory activity. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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17. Application of blue laser direct-writing equipment for manufacturing of periodic and aperiodic nanostructure patterns.
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Chen, Po-Yu, Jywe, Wen-Yuh, Wang, Ming-Shi, and Wu, Chia-Hung
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BLUE lasers , *NANOSTRUCTURES , *DEGREES of freedom , *LASER interferometers , *LITHOGRAPHY , *FIELD programmable analog arrays , *OPTICAL diffraction - Abstract
This study presents the novel development of low cost, highly efficient blue laser direct-writing equipment for using mask-less laser lithography to manufacture periodic and aperiodic nanostructure patterns. The system includes a long-stroke linear motor precision stage (X, Y), a piezoelectric nano-precision stage (Y, θ z ), a 3-DOF (degrees of freedom) laser interferometer measurement system, and a blue laser direct-writing optical system. The 3-DOF laser interferometer measurement system gives the control system feedback for displacement (X, Y, θ z ) of the equipment. The laser processing equipment consists of a blue laser direct-writing optical head, a field-programmable gate array (FPGA) alignment interface, and an optical head servo controller. The optical head operates at a wavelength of 405 nm. Processing the nanostructures on thermo-reaction inorganic resists with precise control of the laser intensity, taking advantage of the threshold effect to exceed the limitations of optical diffraction, and reduces the nanostructure hole size. The equipment can be used to fabricate various periodic nanostructure patterns, aperiodic nanostructure patterns, and two-dimensional patterns. The equipment positioning accuracy is within 50 nm at a speed of 50 mm/s, and the minimum critical dimension can be achieved about 100 nm or so. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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18. Electrochemical study and recovery of Pb using 1:2 choline chloride/urea deep eutectic solvent: A variety of Pb species PbSO4, PbO2, and PbO exhibits the analogous thermodynamic behavior.
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Liao, Yu-Shun, Chen, Po-Yu, and Sun, I-Wen
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ELECTROCHEMICAL analysis , *LEAD compounds , *CHOLINE chloride , *EUTECTIC reactions , *SOLUTION (Chemistry) , *CHEMICAL reduction , *NUCLEATION , *SURFACE morphology - Abstract
Water-insoluble PbSO 4 , PbO 2 , and PbO are fairly soluble in choline chloride/urea deep eutectic solvent (ChCl/urea DES) in 1:2 molar ratio. Very interestingly, solution prepared from PbO 2 exhibits the almost identical electrochemical behavior as those from PbSO 4 and PbO, indicating that Pb(II) is formed in the DES regardless of what Pb compound is introduced. The electrochemical reduction of the Pb(II) species is determined as an irreversible process, and involves the three-dimensional (3D) instantaneous nucleation with diffusion-controlled growth. From the dependence of the diffusion coefficient on temperature, the activation energy for diffusion of PbSO 4 and PbO 2 is determined to be 33.7 and 34.1 kJ mol −1 , respectively. Electrodeposition of Pb was achieved potentiostatically and galvanostatically. The surface morphology of Pb deposits significantly depends on the applied potential and current. The coulombic efficiency of Pb electrodeposition is higher than 90%. Electrodeposition of Pb from a wet DES containing a mixture of three different Pb sources is also investigated. The XRD analysis confirmed that the electrodeposits consisted of metallic Pb. [ABSTRACT FROM AUTHOR]
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- 2016
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19. The relationship of antipsychotic treatment with reduced brown adipose tissue activity in patients with schizophrenia.
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Chen, Po-Yu, Chiu, Chih-Chiang, Hsieh, Tsung-Han, Liu, Yun-Ru, Chen, Chun-Hsin, Huang, Cho-Yin, Lu, Mong-Liang, and Huang, Ming-Chyi
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BROWN adipose tissue , *PSYCHIATRIC rating scales , *PEOPLE with schizophrenia , *BONE morphogenetic proteins , *BODY mass index - Abstract
Antipsychotic drug (APD) treatment has been associated with metabolic abnormalities. Brown adipose tissue (BAT) is the main site of adaptive thermogenesis and secretes various metabolism-improving factors known as batokines. We explored the association of BAT activity with APD treatment and metabolic abnormalities in patients with schizophrenia by measuring the blood levels of bone morphogenetic protein 8b (BMP8b), a batokine secreted by mature BAT. BMP8b levels were compared among 50 drug-free, 32 aripiprazole-treated, and 91 clozapine-treated patients with schizophrenia. Regression analysis was used to explore factors, including APD types, that might be associated with BMP8b levels and the potential effect of BMP8b on metabolic syndrome (MS). APD-treated patients had decreased BMP8b levels relative to drug-free patients. The difference still existed after adjustment for body mass index and Brief Psychiatric Rating Scale scores. Among APD-treated group, clozapine was associated with even lower BMP8b levels than the less obesogenic APD, aripiprazole. Furthermore, higher BMP8b levels were associated with lower risks of MS after adjustment for BMI and APD treatment. Using drug-free patients as the comparison group to understand the effect of APDs, this is the first study to show APD treatment is associated with reduced BAT activity that is measured by BMP8b levels, with clozapine associated a more significant reduction than aripiprazole treatment. BMP8b might have a beneficial effect against metabolic abnormalities and this effect is independent of APD treatment. Future studies exploring the causal relationship between APD treatment and BMP8b levels and the underlying mechanisms are warranted. • BAT is the main site of adaptive thermogenesis that improves metabolic problems. • BMP8b is a batokine secreted by BAT, with levels correlated to BAT activity. • Antipsychotic-treated patients had lower BMP8b levels than drug-free patients. • Clozapine treatment was associated with even lower BMP8b levels than aripiprazole. • Higher BMP8b levels were associated with lower metabolic risks in our patients. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
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20. The Metamorphosis of Industrial Designers from Novices to Experts.
- Author
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Wong, Ju‐Joan, Chen, Po‐Yu, and Chen, Chun‐Di
- Subjects
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DESIGN education in universities & colleges , *CAREER development , *DESIGNERS , *EDUCATION , *TRAINING - Abstract
Professional training for designers is crucial in the field of design studies. The characteristics of novices versus those of expert designers have been identified in the literature; however, studies exploring the issue of professional training processes in the actual workplace are not well developed. Our study addresses the topic by using qualitative research methods along with flexible design. Collected data from the interviewees with different work experience were analysed by open, axial and selective coding. Herein, we argue that the processes by which a designer transforms from a novice into an expert in the industry are constructed through the interaction of several complicated factors. The re-learning inherent in design professions is implemented through knowledge transfer gained from participation in design projects, particularly regarding tacit knowledge. Also, the novice's process of learning and training yields the characteristics and skills that companies and firms require of designers; this process involves a series of disciplinary sub-processes, from destructive to reconstructive, implemented by employers. In these sub-processes, the subjectivity of designers is neglected, leading to the suppression of imaginative expression and feelings of alienation among these workers. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
21. Fabrication of seamless roller mold with 3D micropatterns using inner curved surface photolithography.
- Author
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Tsai, Sung-Wen, Chen, Po-Yu, Huang, Shr-Ren, and Lee, Yung-Chun
- Subjects
- *
FABRICATION (Manufacturing) , *CURVED surfaces , *PHOTOLITHOGRAPHY , *NANOSTRUCTURED materials , *MICROSTRUCTURE - Abstract
Continuous roller imprinting is one of the most promising means of fabricating micro/nano structures over a large area. However, the fabrication of roller molds with seamless and three-dimensional (3D) complex patterns poses a significant challenge. Accordingly, this paper presents an innovative approach for fabricating a seamless hollow roller master mold patterned with discrete or continuous 3D structures. The major steps in the proposed fabrication method include an inner pneumatic rotary photoresist (PR) coating process followed by a step-and-rotate lithography process or a continuous rotation lithography process. Having fabricated the master mold, the microstructure patterns are transferred to a roller by means of a polydimethyl-siloxane (PDMS) casting technique. The effectiveness of the proposed method is demonstrated by patterning a PDMS-casted roller mold with wavy microstructures and then using the roller mold to fabricate a diffusion optical film. The experimental results show that the diffusion film has a haze of 97.1% and a total transmittance of 91.6%. [ABSTRACT FROM AUTHOR]
- Published
- 2016
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- View/download PDF
22. Mood stabilizers and risk of all‐cause, natural, and suicide mortality in bipolar disorder: A nationwide cohort study.
- Author
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Chen, Pao‐Huan, Tsai, Shang‐Ying, Chen, Po‐Yu, Pan, Chun‐Hung, Su, Sheng‐Siang, Chen, Chiao‐Chicy, and Kuo, Chian‐Jue
- Subjects
- *
MOOD stabilizers , *BIPOLAR disorder , *COHORT analysis , *SUICIDE , *MORTALITY - Abstract
Objectives: People with bipolar disorder have an elevated risk of mortality. This study evaluated associations between the use of mood stabilizers and the risks of all‐cause mortality, suicide, and natural mortality in a national cohort of people with bipolar disorder. Methods: In this nationwide cohort study, we used data from January 1, 2000, to December 31, 2016, collected from Taiwan's National Health Insurance Research Database and included 25,787 patients with bipolar disorder. Of these patients, 4000 died during the study period (including 760 and 2947 from suicide and natural causes, respectively). Each standardized mortality ratio (SMR) was calculated as the ratio of observed mortality in the bipolar cohort to the number of expected deaths in the general population. Multivariable Cox proportional hazards regression with a time‐dependent model was performed to estimate the hazard ratio (HR) of each mood stabilizer with each mortality outcome. Results: The SMRs of all‐cause mortality, suicide, and natural mortality in the bipolar disorder cohort were 5.26, 26.02, and 4.68, respectively. The use of mood stabilizers was significantly associated with decreased risks of all‐cause mortality (adjusted HR [aHR] = 0.58, p< 0.001), suicide (aHR = 0.60, p < 0.001), and natural mortality (aHR = 0.55, p < 0.001) within a 5‐year follow‐up period after index admission. Among the individual mood stabilizers, lithium was associated with the lowest risks of all‐cause mortality (aHR = 0.38, p < 0.001), suicide (aHR = 0.39, p < 0.001), and natural mortality (aHR = 0.37, p < 0.001). Conclusion: In addition to having protective effects against suicide and all‐cause mortality, mood stabilizers also exert a substantial protective effect against natural mortality, with lithium associated with the lowest risk of mortality. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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- View/download PDF
23. Distributed Real-Time Anomaly Detection in Networked Industrial Sensing Systems.
- Author
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Chen, Po-Yu, Yang, Shusen, and McCann, Julie A.
- Subjects
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ANOMALY detection (Computer security) , *WIRELESS sensor network security , *REAL-time computing , *ACTUATORS , *DISTRIBUTED computing - Abstract
Reliable real-time sensing plays a vital role in ensuring the reliability and safety of industrial cyberphysical systems (CPSs) such as wireless sensor and actuator networks. For many reasons, such as harsh industrial environments, fault-prone sensors, or malicious attacks, sensor readings may be abnormal or faulty. This could lead to serious system performance degradation or even catastrophic failure. Current anomaly detection approaches are either centralized and complicated or restricted due to strict assumptions, which are not suitable for practical large-scale networked industrial sensing systems (NISSs), where sensing devices are connected via digital communications, such as wireless sensor networks or smart grid systems. In this paper, we introduce a fully distributed general anomaly detection (GAD) scheme, which uses graph theory and exploits spatiotemporal correlations of physical processes to carry out real-time anomaly detection for general large-scale NISSs. We formally prove the scalability of our GAD approach and evaluate the performance of GAD for two industrial applications: building structure monitoring and smart grids. Extensive trace-driven simulations validate our theoretical analysis and demonstrate that our approach can significantly outperform state-of-the-art approaches in terms of detection accuracy and efficiency. [ABSTRACT FROM PUBLISHER]
- Published
- 2015
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24. Detection of false data injection attacks in smart-grid systems.
- Author
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Chen, Po-Yu, Yang, Shusen, McCann, Julie A., Lin, Jie, and Yang, Xinyu
- Subjects
- *
SMART power grids , *DATA transmission systems , *ELECTRIC power transmission management , *ELECTRIC power distribution management , *SIMULATION methods & models - Abstract
Smart grids are essentially electric grids that use information and communication technology to provide reliable, efficient electricity transmission and distribution. Security and trust are of paramount importance. Among various emerging security issues, FDI attacks are one of the most substantial ones, which can significantly increase the cost of the energy distribution process. However, most current research focuses on countermeasures to FDIs for traditional power grids rather smart grid infrastructures. We propose an efficient and real-time scheme to detect FDI attacks in smart grids by exploiting spatial-temporal correlations between grid components. Through realistic simulations based on the US smart grid, we demonstrate that the proposed scheme provides an accurate and reliable solution. [ABSTRACT FROM PUBLISHER]
- Published
- 2015
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25. Group-Sparse Signal Denoising: Non-Convex Regularization, Convex Optimization.
- Author
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Chen, Po-Yu and Selesnick, Ivan W.
- Subjects
- *
CONVEX domains , *MATHEMATICAL regularization , *COST functions , *SIGNAL processing , *SIGNAL-to-noise ratio - Abstract
Convex optimization with sparsity-promoting convex regularization is a standard approach for estimating sparse signals in noise. In order to promote sparsity more strongly than convex regularization, it is also standard practice to employ non-convex optimization. In this paper, we take a third approach. We utilize a non-convex regularization term chosen such that the total cost function (consisting of data consistency and regularization terms) is convex. Therefore, sparsity is more strongly promoted than in the standard convex formulation, but without sacrificing the attractive aspects of convex optimization (unique minimum, robust algorithms, etc.). We use this idea to improve the recently developed ‘overlapping group shrinkage’ (OGS) algorithm for the denoising of group-sparse signals. The algorithm is applied to the problem of speech enhancement with favorable results in terms of both SNR and perceptual quality. [ABSTRACT FROM PUBLISHER]
- Published
- 2014
- Full Text
- View/download PDF
26. Fabrication of a seamless roller mold with wavy microstructures using mask-less curved surface beam pen lithography.
- Author
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Tsai, Sung-Wen, Chen, Po-Yu, and Lee, Yung-Chun
- Subjects
- *
MICROFABRICATION , *MICROSTRUCTURE , *LITHOGRAPHY , *ROLLERS (Printing) , *TECHNOLOGICAL innovations , *COATING processes - Abstract
Roller imprinting is one of the most commonly used methods for the fabrication of continuous functional structures over large areas. However, the fabrication of roller molds with seamless and complex patterns poses a significant challenge. This paper presents an innovative technique for fabricating a seamless roller mold with wavy microstructures using a novel mask-less curved surface beam pen lithography technique. The major steps in the proposed technique include spray coating a thin photo-resist (PR) layer on the roller, exposing the PR layer though a translating micro-lens array (MLA), etching the patterned PR layer, and electro-polishing the etched microstructures. The proposed method is used to pattern roller molds with different wavy microstructures by varying the rotation speed of the roller, the translation speed of the MLA holder, and the translation distance of the MLA holder. The patterned metal roller molds are then used to replicate wavy microstructures on a thin polyethylene terephthalate substrate by means of continuous UV-type roller imprinting methods. The line-width and height of the wavy microstructure are 84.5 µm and 25.5 µm, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
27. Translation-invariant shrinkage/thresholding of group sparse signals.
- Author
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Chen, Po-Yu and Selesnick, Ivan W.
- Subjects
- *
SIGNAL denoising , *SIGNAL processing , *MATHEMATICAL models , *COMPUTER algorithms , *COST functions , *FOURIER transforms - Abstract
Abstract: This paper addresses signal denoising when large-amplitude coefficients form clusters (groups). The L1-norm and other separable sparsity models do not capture the tendency of coefficients to cluster (group sparsity). This work develops an algorithm, called ‘overlapping group shrinkage’ (OGS), based on the minimization of a convex cost function involving a group-sparsity promoting penalty function. The groups are fully overlapping so the denoising method is translation-invariant and blocking artifacts are avoided. Based on the principle of majorization–minimization (MM), we derive a simple iterative minimization algorithm that reduces the cost function monotonically. A procedure for setting the regularization parameter, based on attenuating the noise to a specified level, is also described. The proposed approach is illustrated on speech enhancement, wherein the OGS approach is applied in the short-time Fourier transform (STFT) domain. The OGS algorithm produces denoised speech that is relatively free of musical noise. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
28. Spiral nanoporous gold electrode: A simple strategy for enhancing the attenuated-total-reflection infrared spectroelectrochemical sensitivity.
- Author
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Chen, Po-Yu, Chien, Da-Jean, and Huang, Genin-Gary
- Subjects
- *
GOLD electrodes , *GOLD nanoparticles , *ELECTROCHEMISTRY , *FUEL cells , *SENSITIVITY analysis , *ANTIOXIDANTS , *FERRICYANIDES - Abstract
Highlights: [•] A new designed ATR-IR-SEC cell was used for spectroelectrochemical analysis. [•] A conventional three-electrode cell was used. [•] A spiral nanoporous gold electrode was used to enhance the sensitivity. [•] Ferricyanide and two antioxidants were determined using this new cell. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
29. Antipsychotic medications and severe sepsis in schizophrenia: A nested case–control study.
- Author
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Chang, Chun-Wei, Chen, Wen-Yin, Chen, Po-Yu, Pan, Chun-Hung, Su, Sheng-Shiang, Tsai, Shang-Ying, Chen, Chiao-Chicy, and Kuo, Chian-Jue
- Abstract
Sepsis constitutes a condition that involves life-threatening organ dysfunction induced by severe infection. This nested case–control study investigated risk factors for severe sepsis and whether antipsychotic use is associated with severe sepsis risk in patients with schizophrenia, a topic that has not been comprehensively explored in previous studies.We selected 39,432 patients with schizophrenia aged between 15 and 65 years from Taiwan’s Psychiatric Inpatient Medical Claims database for the period 2000–2012. The case group comprised patients with severe sepsis after their first psychiatric admission (
n = 1382). The case and control groups were randomly matched (1:4) by age, sex and first psychiatric admission (year) and finally comprised 1382 and 5528 individuals, respectively. We employed multivariable conditional logistic regression to identify (1) risk factors (physical illnesses and nonpsychiatric medications) and (2) antipsychotic–severe sepsis associations.Higher numbers of psychiatric admissions and physical illnesses such as delirium, cerebrovascular disease and cancer were significantly associated with a higher risk of severe sepsis. Furthermore, severe sepsis was associated with the use of antithrombotic agents, systemic corticosteroids and agents targeting the renin–angiotensin system. Clozapine (adjusted risk ratio = 1.65) and quetiapine (adjusted risk ratio = 1.59) use were associated with an increased risk of severe sepsis. The use of more than one antipsychotic drug could further increase this risk.Several physical illnesses and nonpsychiatric medications increase the risk of severe sepsis in patients with schizophrenia. Specifically, clozapine or quetiapine use significantly increased the risk of severe sepsis in these patients. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
30. Fabrication of macroporous Pt and PtAu electrodes for electrochemical application through galvanic replacement at macroporous Cu electrode electrodeposited at polystyrene template from room temperature ionic liquid
- Author
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Huang, Shu-Jian and Chen, Po-Yu
- Subjects
- *
POROUS materials , *PLATINUM electrodes , *ELECTROCHEMICAL analysis , *ELECTRIC batteries , *ELECTROPLATING , *SUBSTITUTION reactions , *GOLD electrodes , *COPPER electrodes , *POLYSTYRENE , *IONIC liquids - Abstract
Abstract: Macroporous Pt and PtAu electrodes (MP-Pt and MP-PtAu) were prepared through galvanic replacement at macroporous Cu electrodes, which were formed by electrodeposition of Cu at Au-coated indium tin oxide (Au/ITO) electrodes covered with ordered arrays of polystyrene (PS) nanospheres (PS/Au/ITO) in N-butyl-N-methylpyrrolidinium dicyanamide room temperature ionic liquid (BMP-DCA RTIL). After dissolving the PS templates in tetrahydrofuran (THF), macroporous Cu electrodes (MP-Cu/Au/ITO; denoted as MP-Cu hereafter) were obtained. The surface of a MP-Cu was spontaneously replaced by Pt or Pt/Au when a MP-Cu was immersed in an aqueous solution containing H2PtCl6 or H2PtCl6/HAuCl4 to form the MP-Pt (actually, MP-Pt/Cu/Au/ITO) or MP-PtAu electrodes. The atomic ratios of Au in PtAu could be adjusted by changing the concentration of HAuCl4 in the mixtures of H2PtCl6/HAuCl4. The electrodeposition potential, the time of replacement reaction, the concentrations of H2PtCl6 and HAuCl4, and the content of surfactant, which influence the structure of macroporous electrodes, were investigated. The surface morphologies of these macroporous electrodes were characterized with scanning electron microscope (SEM). MP-PtAu electrodes showed the better performance than the MP-Pt electrodes on the electrocatalytic oxidation of ethanol in alkaline solutions. [Copyright &y& Elsevier]
- Published
- 2013
- Full Text
- View/download PDF
31. Biological materials: Functional adaptations and bioinspired designs
- Author
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Chen, Po-Yu, McKittrick, Joanna, and Meyers, Marc André
- Subjects
- *
BIOLOGICAL specimen analysis , *TENSILE strength , *VISCOELASTICITY , *DAMPING (Mechanics) , *BIONICS , *MECHANICAL behavior of materials , *BIOMATERIALS - Abstract
Abstract: Biological materials are typically multifunctional but many have evolved to optimize a chief mechanical function. These functions include impact or fracture resistance, armor and protection, sharp and cutting components, light weight for flight, or special nanomechanical/chemical extremities for reversible adhesive purposes. We illustrate these principles through examples from our own research as well as selected literature sources. We conduct this analysis connecting the structure (nano, micro, meso, and macro) to the mechanical properties important for a specific function. In particular, we address how biological systems respond and adapt to external mechanical stimuli. Biological materials can essentially be divided into mineralized and non-mineralized. In mineralized biological materials, the ceramics impart compressive strength, sharpness (cutting edges), and stiffness while the organic components impart tensile strength, toughness and ductility. Non-mineralized biological materials in general have higher tensile than compressive strength, since they are fibrous. Thus, the mineralized components operate optimally in compression and the organic components in tension. There is a trade-off between strength and toughness and the stiffness and density, with optimization. Mineralization provides load bearing capability (strength and stiffness) whereas the biopolymer constituents provide viscoelastic damping and toughness. The most important component of the nascent field of Biological Materials Science is the development of bioinspired materials and structures and understanding of the structure–property relationships across various length scales, from the macro-down to the molecular level. The most successful efforts at developing bioinspired materials that attempt to duplicate some of the outstanding properties are presented. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
32. Voltammetric study and electrodeposition of copper in 1-butyl-3-methylimidazolium salicylate ionic liquid
- Author
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Chen, Po-Yu and Chang, Yu-Ting
- Subjects
- *
COPPER , *ELECTROFORMING , *METHYL groups , *SALICYLATES , *IONIC liquids , *CARBON electrodes , *VOLTAMMETRY - Abstract
Abstract: The voltammetric behavior of cuprous ions has been studied at disk electrodes of glassy carbon and polycrystalline platinum in a new hydrophilic 1-butyl-3-methylimidazolium salicylate ionic liquid (BMI-SAL IL). Cuprous ions Cu(I) were introduced into the IL by the anodic dissolution of a Cu wire electrode or by the addition of CuCl. This air- and water-stable hydrophilic IL is very similar to dicyanamide (DCA)-based ILs because both DCA anions and salicylate (SAL) anions have very strong ligand properties; therefore, many metal salts, such as metal halides, are very soluble in this IL. However, the source of SAL anions, sodium salicylate, is considerably cheaper than sodium dicyanamide salt. The potentiostatic electrodeposition of copper onto iron substrates has also been investigated in this study. The surface morphologies of the copper deposits were significantly altered by the electrodeposition potential; granular, mirror-like, and porous copper deposits could be obtained at different negative potentials. The activity of the copper deposit-modified iron electrodes toward the electrochemical nitrate reduction in alkaline solutions was found to significantly depend on the surface morphologies. The granular and the porous surfaces showed better activities. The mirror-like surface, however, had no activity on the electrochemical nitrate reduction. [Copyright &y& Elsevier]
- Published
- 2012
- Full Text
- View/download PDF
33. Effects of Annealing Solventson the Morphology ofBlock Copolymer-Based Supramolecular Thin Films.
- Author
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Huang, Wei-Han, Chen, Po-Yu, and Tung, Shih-Huang
- Subjects
- *
BLOCK copolymers , *THIN film devices , *POLYSTYRENE , *HYDROGEN bonding , *OXYGEN , *CHLOROFORM , *SUPRAMOLECULAR chemistry - Abstract
We report a strategy that combines supramolecular assemblyandsolvent annealing to manipulate the microdomain orientation in blockcopolymer thin films. In supramolecular thin films formed by polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) with3-pentadecylphenol (PDP) hydrogen-bonded onto P4VP blocks, where PSblocks phase-separate into cylindrical microdomains, we found thatthe orientation of PS cylinders can be controlled by using differenttypes of solvents to anneal the films. As films are annealed underthe vapors of solvents bearing no oxygen atoms, such as chloroform,PS cylinders are perpendicular to the surface, while under those ofsolvents bearing oxygen, such as THF, PS cylinders are parallel tothe surface. Furthermore, the orientation is switchable upon the alternateuse of different types of solvents. The 1H NMR measurementsshowed that the strengths of hydrogen bonds between PDP and P4VP aregreatly weakened in oxygen-bearing solvents due to the competitionof the highly electronegative oxygen atoms. We thus suggest that thebinding capability of PDP onto P4VP is the key to determine whetherthe supramolecules can be assembled in the vapors of different typesof solvents, which in turn, regulates the orientation of PS cylinders. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
34. Association of plasma retinol-binding protein-4, adiponectin, and high molecular weight adiponectin with metabolic adversities in patients with schizophrenia
- Author
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Chen, Po-Yu, Huang, Ming-Chyi, Chiu, Chih-Chiang, Liu, Hsing-Cheng, Lu, Mong-Liang, and Chen, Chun-Hsin
- Subjects
- *
ADIPONECTIN , *PEOPLE with schizophrenia , *PROTEIN analysis , *PATIENTS , *POPULATION , *CLOZAPINE , *HALOPERIDOL , *BODY mass index , *HIGH density lipoproteins , *INSULIN therapy , *LONGITUDINAL method , *THERAPEUTICS , *DISEASES - Abstract
Abstract: Objective: Metabolic adversities are prevalent in patients with schizophrenia. Retinol-binding protein 4 (RBP4) and high molecular weight (HMW) adiponectin have been recently found to be associated with metabolic features in non-psychiatric population. The study aimed to evaluate the associations between metabolic features and RBP4, total adiponectin, and HMW adiponectin in patients with schizophrenia. Methods: We recruited 109 patients with schizophrenia treated with clozapine or haloperidol and evaluated their body mass index (BMI), waist circumference, blood pressure, and fasting triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), fasting plasma glucose, insulin, RBP4, total adiponectin, and HMW adiponectin levels. Results: We found that patients with metabolic syndrome (MS) had higher RBP4 level, and lower total adiponectin and HMW adiponectin levels than those without MS. There were no significant differences in metabolic features and adipocytokine levels between patients treated with clozapine and haloperidol. Most of the metabolic indexes were significantly correlated with the levels of adipocytokines. After adjusting the effects of age, gender, and BMI, marginal significant correlations existed between TG and RBP4 levels; HDL-C and total adiponectin and HMW adiponectin; insulin and HOMA-IR and HMW adiponectin. Receiver operating curve analysis showed that all of the three adipocytokines could differentiate patients with MS from those without MS. Meanwhile, total adiponectin and HMW adiponectin, but not RBP4, had the differentiating power for insulin resistance. Conclusion: Higher RBP4 and lower total adiponectin and HMW adiponectin levels were observed in schizophrenic patients with MS. Only HMW adiponectin is marginally correlated with insulin sensitivity. The finding that metabolic profiles, but not the antipsychotic types, are associated with adipocytokine levels should be confirmed in longitudinal studies. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
35. Formation of noble metal nanoparticles through chemical reduction induced by coordination-alteration of complex ions in ionic liquids and electroanalytical application
- Author
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Chen, Po-Yu and Huang, Hsin-Yi
- Subjects
- *
NANOPARTICLES , *PRECIOUS metals , *COMPLEX ions , *IONIC liquids , *TRANSITION metal ions , *LIGANDS (Chemistry) , *ELECTROLYSIS , *STABILIZING agents - Abstract
Abstract: Au, Pd, and AuPd nanoparticles (NPs) were formed in ionic liquid (IL) by coordination alteration-induced redox reaction. The different affinity between transition metal ions and anionic ligands leads to the huge redox potential change when IL anion-coordinated Fe(II) or Cu(I) ions were mixed with Cl−-coordinated Au(I) or Pd(II) ions in appropriate IL, which results in a spontaneous redox reaction accompanied with the formation of NPs without additional stabilizing reagents. By manipulating the molar ratios of Fe(II) or Cu(I) to Au(I) or Pd(II), the particle size could be changed. A new technique was developed to prepare NPs-IL-carbon paste electrodes (NPs-IL-CPEs) without the use of mortar and pestle. The electrodes were used in electrochemical analysis to prove the feasibility of the entire procedure. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
36. Interphase precipitation of nanometer-sized carbides in a titanium–molybdenum-bearing low-carbon steel
- Author
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Yen, Hung-Wei, Chen, Po-Yu, Huang, Ching-Yuan, and Yang, Jer-Ren
- Subjects
- *
CARBON steel , *PRECIPITATION (Chemistry) , *NANOSTRUCTURED materials , *TITANIUM compounds , *PHASE transitions , *TRANSMISSION electron microscopy , *HARDNESS , *STRENGTH of materials - Abstract
Abstract: The interphase-precipitated nanometer-sized carbides formed in a Ti–Mo-bearing steel after isothermal transformation in a temperature range of 630–720°C for 30min have been investigated by field-emission-gun transmission electron microscopy. The characteristic sheets of interphase precipitation were identified as planar and curved. The planar sheets of carbides have been analyzed and found to be oriented close to ferrite planes {211}, {210} and {111}; transmission electron microscopy results provide strong evidence to suggest that the development of interphase-precipitated carbides can be associated with the growth of incoherent ferrite/austenite interface by the ledge mechanism. Carbide size, sheet spacing and intercarbide spacing have been measured or estimated. The lower transformation temperature produces finer and denser carbides, and results in a higher hardness of ferrite. The contribution of the interphase precipitation hardening to the yield strength of the steel studied has been estimated, based on the Orowan mechanism. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
37. A study of the dynamic compressive behavior of Elk antler
- Author
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Kulin, Robb M., Chen, Po-Yu, Jiang, Fengchun, and Vecchio, Kenneth S.
- Subjects
- *
MATERIALS compression testing , *STIFFNESS (Mechanics) , *BONE mechanics , *FRACTURE mechanics , *ANTLERS , *STRENGTH of materials , *HYDRATION , *DEFORMATIONS (Mechanics) , *HOPKINSON bars (Testing) - Abstract
Abstract: Large mammalian antler is extremely tough and fracture resistant compared to other more brittle forms of skeletal bone. The ability of antler to resist fracture is associated with a decrease in material stiffness and yield strength and increased non-linear response, due in part to antler being fast growing, since they are typically shed and regrown annually. Since male Elk commonly engage in antler sparring as a means of making dominance displays, the ability to withstand large impacts suggest that antler may exhibit strain-rate dependent behavior even greater than skeletal bone. To evaluate this hypothesis, specimens of antler were tested in compression over a range of strain rates. Specimens were loaded either along or transversely to the osteonal growth direction, in wet and dry conditions. Results showed that antler exhibits higher compressive strengths at increased strain rates, and that strain rate and hydration are greater determinants of compressive strength than osteonal orientation. In addition, antler can sustain compressive strains a full order-of-magnitude greater than in mammalian long bone. Failed specimens showed that a hierarchical chain of deformation mechanisms sustains the large bulk strains supported by antler. These mechanisms appear to be less brittle and more fibrous than those seen previously in skeletal bone. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
38. Minerals form a continuum phase in mature cancellous bone.
- Author
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Chen, Po-Yu, Toroian, Damon, Price, Paul, McKittrick, Joanna, and Price, Paul A
- Subjects
- *
MINERALS in the body , *BONES , *BIOMINERALIZATION , *COMPOSITE materials , *ELECTRON microscopy , *COLLAGEN , *APATITE in the body , *BONE metabolism , *BIOLOGICAL models , *HEAT , *RESEARCH , *CATTLE , *ANIMAL experimentation , *SCANNING electron microscopy , *RESEARCH methodology , *MEDICAL cooperation , *EVALUATION research , *COMPARATIVE studies , *HISTOLOGICAL techniques , *MINERALS - Abstract
Bone is a hierarchically structured composite consisting of a protein phase (type I collagen) and a mineral phase (carbonated apatite). The objective of this study was to investigate the hierarchical structure of mineral in mature bone. A method to completely deproteinize bone without altering the original structure is developed, and the completion is confirmed by protein analysis techniques. Stereoscopy and field emission electron microscopy are used to examine the structural features from submillimeter- to micrometer- to nanometer-length scales of bovine femur cancellous bone. Stereoscopic images of fully deproteinized and demineralized bovine femur cancellous bone samples show that fine trabecular architecture is unaltered and the microstructural features are preserved, indicating the structural integrity of mineral and protein constituents. SEM revealed that bone minerals are fused together and form a sheet-like structure in a coherent manner with collagen fibrils. Well-organized pore systems are observed at varying hierarchical levels. Mineral sheets are peeled off and folded after compressive deformation, implying strong connection between individual crystallites. Results were compared with commercially available heat-deproteinized bone (Bio-Oss(®)), and evidence showed consistency in bone mineral structure. A two-phase interpenetrating composite model of mature bone is proposed and discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
39. Voltammetric behavior of Pd(II) and Ni(II) ions and electrodeposition of PdNi bimetal in N-butyl-N-methylpyrrolidinium dicyanamide ionic liquid
- Author
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Huang, Hsin-Yi and Chen, Po-Yu
- Subjects
- *
VOLTAMMETRY , *PALLADIUM compounds , *NICKEL compounds , *ELECTROFORMING , *LAMINATED metals , *PYRROLES , *CALCIUM cyanamide , *IONIC liquids - Abstract
Abstract: In this study, the voltammetric behavior of Pd(II), Ni(II), and mixtures of Pd(II) and Ni(II) was carried out in room-temperature N-butyl-N-methylpyrrolidinium dicyanamide ionic liquid (BMP-DCA IL). Electrodeposition of PdNi bimetal was achieved by controlled-potential electrolysis at iron wire electrodes from BMP-DCA containing various molar ratios of PdCl2/NiCl2. BMP-DCA shows good solubilities to PdCl2 and NiCl2, respectively, leading to the convenience for preparing the electrodepositing baths. By tuning the molar ratios of Pd(II)/Ni(II) in the electrodepositing baths and/or the applied potentials, PdNi coatings with various atomic contents of Pd could be obtained. Among these PdNi bimetallic coatings, the PdNi coatings with atomic ratios of ∼80/20 had the highest oxidation current in methanol oxidation reaction (MOR) in 1M NaOH and exhibited the best poisoning tolerance. Powder X-ray diffraction analysis indicated that two separate metallic phases belonging to Pd and Ni existed in the PdNi coatings. The diffraction signal of Pd was very broad, indicating the tiny crystal size of Pd in the bimetal coatings. The scanning electron spectroscopic micrographs of PdNi coatings demonstrated that the Pd∼80Ni∼20 coatings had three-dimensional structures. This morphological characteristic implied that the composition and the surface morphology of the PdNi coatings equivalently contributed to the electrocatalytic activity toward MOR. The Pd∼80Ni∼20-coated iron-electrode (Fe/Pd∼80Ni∼20) was used to detect methanol and the linearity was observed in 3.53μM to 758.88μM using hydrodynamic chronoamperometry where a potential of −0.1V (vs. Ag/AgCl) was applied. [Copyright &y& Elsevier]
- Published
- 2011
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40. PdNi- and Pd-coated electrodes prepared by electrodeposition from ionic liquid for nonenzymatic electrochemical determination of ethanol and glucose in alkaline media
- Author
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Huang, Hsin-Yi and Chen, Po-Yu
- Subjects
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COATED electrodes , *ELECTROFORMING , *IONIC liquids , *ALLOY plating , *VOLTAMMETRY , *VITAMIN C , *URIC acid , *ACETAMINOPHEN - Abstract
Abstract: Nonenzymatic electrochemical determination of ethanol and glucose was respectively achieved using PdNi- and Pd-coated electrodes prepared by electrodeposition from the novel metal-free ionic liquid (IL); N-butyl-N-methylpyrrolidinium dicyanamide (BMP-DCA). BMP-DCA provided an excellent environment and wide cathodic limit for electrodeposition of metals and alloys because many metal chlorides could dissolve in this IL where the reduction potentials of Pd(II) and Ni(II) indeed overlapped, leading to the convenience of potentiostatic codeposition. In aqueous solutions, the reduction potentials of Pd(II) and Ni(II) are considerably separated. The bimetallic PdNi coatings with atomic ratios of ∼80/20 showed the highest current for ethanol oxidation reaction (EOR). Ethanol was detected by either cyclic voltammetry (CV) or hydrodynamic amperometry (HA). Using CV, the dependence of EOR peak current on concentration was linear from 4.92 to 962μM with a detection limit of 2.26μM (σ =3), and a linearity was observed from 4.92 to 988μM using HA (detection limit 0.83μM (σ =3)). The Pd-coated electrodes prepared by electrodeposition from BMP-DCA showed electrocatalytic activity to glucose oxidation and CV, HA, and square-wave voltammetry (SWV) were employed to determine glucose. SWV showed the best sensitivity and linearity was observed from 2.86μM to 107μM, and from 2.99mM to 10.88mM with detection limits of 0.78μM and 25.9μM (σ =3), respectively. For glucose detection, the interference produced from ascorbic acid, uric acid, and acetaminophen was significantly suppressed, compared with a regular Pt disk electrode. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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41. Effects of deposition parameters on characteristics of carbon coatings on optical fibers prepared by thermal chemical vapor deposition
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Shiue, Sham-Tsong, Chen, Po-Yu, Lee, Ren-Hung, Chen, Tsuen-Sung, and Lin, Hung-Yi
- Subjects
- *
OPTICAL fibers , *SURFACE coatings , *CARBON , *CHEMICAL vapor deposition , *TEMPERATURE effect , *MICROSTRUCTURE , *ELECTRIC resistance , *METHANE - Abstract
Abstract: The effects of deposition parameters on characteristics of carbon coatings on optical fibers prepared by thermal chemical vapor deposition are investigated. The deposition parameters are selected as follows. The CH4/(CH4 +N2) ratio is in the range between 20% and 100%; the temperature is set from 1173 to 1248K; the working pressure is arranged between 50 and 100 kPa, and the residence time is ranging from 1.47 to 7.37s. The deposition rate, microstructure, and electrical resistivity of carbon coatings are measured. The low-temperature surface morphology of carbon-coated optical fibers is elucidated. Experimental results indicate that the deposition rate increases with increasing the CH4/(CH4 +N2) ratio, deposition temperature, working pressure, and residence time. The activation energy (= 456kJ/mol) of carbon deposition from methane was shown to correlate to the activation energy of methane dissociation. The deposition rate is proportional to about first-order of partial pressure of methane, and thus, the deposition process is mainly controlled by the process to create mono-carbon species in the carbon film. As the deposition rate increases, the size and number of particles on the carbon coating surface and electrical resistivity of carbon coatings increase, while the ordered degree, nano-crystallite size, and sp2 carbon atoms of the carbon coatings decrease. Additionally, the low-temperature surface morphology of carbon coatings shows that as the carbon coating thickness is large enough to sustain the thermal loading, decreasing the deposition rate is good for producing hermetic optical fiber coatings. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
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42. Effects of substrate size on properties of carbon coatings on glass cylinder substrates prepared by thermal chemical vapor deposition
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Chen, Po-Yu, Shiue, Sham-Tsong, and Lin, Hung-Yi
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- *
PROTECTIVE coatings , *CARBON , *SUBSTRATES (Materials science) , *GLASS , *CHEMICAL vapor deposition , *OPTICAL fibers , *SURFACE roughness , *RAMAN effect , *ELECTRIC resistance - Abstract
Abstract: The effect of the substrate size on the properties of carbon coatings that are deposited on the glass cylinder substrates by thermal chemical vapor deposition is investigated. Experimental results show that the deposition rate of carbon coatings decreases as the diameter of the glass cylinder increases, because the residence time of the precursor gas in the deposition zone decreases and the deposition area of the substrate increases. Experimental results also reveal that the surface roughness and electrical resistivity of carbon coatings decrease as the diameter of the glass cylinder increases, while the degree of ordering and crystallite size of the carbon coatings increase. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
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43. Electrochemical codeposition of copper and manganese from room-temperature N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid
- Author
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Chen, Po-Yu, Deng, Ming-Jay, and Zhuang, Ding-Xuan
- Subjects
- *
COPPER-magnesium alloys , *ALLOY plating , *PYRROLIDINE , *IONIC liquids , *IMIDES , *VOLTAMMETRY , *ELECTRODES , *X-ray diffraction - Abstract
Abstract: The voltammetric behavior of N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ionic liquid (BMP-TFSI) containing Cu(I), Mn(II), or mixtures of Cu(I) and Mn(II) as well as the electrodeposition of copper–manganese alloy coatings (Cu–Mn alloy coatings) was studied at 323K. The Cu(I) and Mn(II) species required to prepare these coatings were introduced into the BMP-TFSI by anodic dissolution of the relevant metallic electrodes. Electrodeposits of Cu, Mn, and Cu–Mn with various contents of Mn can be obtained by controlled-potential electrolysis. It was found that the compositions and surface morphology of the electrodeposited Cu–Mn alloy coatings depend on the deposition potentials and the concentration ratio of [Cu(I)]/[Mn(II)] in BMP-TFSI. The Cu–Mn alloy coatings obtained in this study were compact and adherent. They did not show any significant X-ray diffraction signal that could be assigned to the crystalline structures of Cu, Mn, or Cu–Mn alloys. In the aqueous solution containing 0.1M NaCl, the Cu–Mn alloy coatings demonstrated passive behavior—no continuous oxidation was observed. However, a significant oxidation current was observed at the electrodes deposited with Cu or Mn. [Copyright &y& Elsevier]
- Published
- 2009
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44. Electrochemical formation of polycarbazole films in air- and water-stable room-temperature ionic liquids
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Zhuang, Ding-Xuan and Chen, Po-Yu
- Subjects
- *
CARBAZOLE , *POLYMERIZATION , *IONIC liquids , *INDIUM compounds , *VOLTAMMETRY , *ELECTROLYSIS - Abstract
Abstract: Carbazole was electropolymerized on indium tinoxide (ITO) electrodes in two air- and water-stable room-temperature ionic liquids, 1-butyl-3-methylimidazolium hexafluorophosphate (BMI-PF6) and N-butyl-N-methylpyrrolidinium bis((trifluoromethyl)sulfonyl)imide (BMP-TFSI), respectively, using three potentiostatic methods (i.e., cyclic voltammetry, potentiostatic electrolysis, and potentiostatic pulse electrolysis). The polymer films obtained in both ionic liquids (ILs) adhered on the electrode surface well; however, the polycarbazole (PCz) films obtained in the more viscous BMI-PF6 exhibited a denser structure. The PCz films showed electrochromic behavior; deep green was observed in the oxidative state and pale green in the reductive state. Anions or viscosities of the ILs seem to influence the depth of color change. PCz films were also prepared under a normal atmosphere. [Copyright &y& Elsevier]
- Published
- 2009
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45. Increased Nectin-4 levels in chronic ketamine abusers and the relationship with lower urinary tract symptoms.
- Author
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Chang, Hu-Ming, Chen, Po-Yu, Fang, Chiu-Ping, Liu, Tung-Hsia, Wu, Chun-Te, Hsu, Yu-Chao, Kuo, Hsiang-Wei, Liu, Yu-Li, and Huang, Ming-Chyi
- Subjects
- *
KETAMINE , *URINARY organs , *SYMPTOMS , *CELL adhesion molecules , *UROTHELIUM , *KETAMINE abuse - Abstract
• Nectin-4 might play a role in addiction development and urological complications. • Nectin-4 levels are higher in chronic ketamine abusers than controls. • Ketamine users with urological symptoms had lower Nectin-4 levels than those without. • A compromised upregulation of Nectin-4 might be associated with bladder toxicity. Persistent ketamine use causes susceptibility to addiction and bladder toxicity. We examined the association of lower urinary tract symptoms and levels of Nectin-4, a member of the cell adhesion molecules that is essential for maintaining the urothelium barrier in chronic ketamine abusers. We measured the plasma levels of Nectin-4 in 88 patients with ketamine dependence and 69 controls. Patients with ketamine dependence were assessed for ketamine use variables, psychological symptoms, and lower urinary tract symptoms. We found Nectin-4 levels were increased in ketamine-dependent patients compared to the controls (p < 0.0001). Patients with urinary tract symptoms exhibited lower Nectin-4 levels than those without (p = 0.021). Our results suggest an up-regulation of Nectin-4 following chronic and heavy ketamine use. Patients with ketamine dependence with a compromised upregulation of Nectin-4 are likely to have more severe urinary tract symptoms. The mechanisms underlying the involvement of Nectin-4 in ketamine addiction and bladder toxicity warrant future investigation. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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46. Voltammetric study and electrochemical detection of hexavalent chromium at gold nanoparticle-electrodeposited indium tinoxide (ITO) electrodes in acidic media
- Author
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Tsai, Ming-Chih and Chen, Po-Yu
- Subjects
- *
ELECTROCHEMICAL analysis , *ELECTRIC resistors , *CHROMIUM group , *NANOPARTICLES - Abstract
Abstract: The voltammetric behavior of hexavalent chromium species (Cr(VI)) was respectively studied at ITO, bulk Au, and Au-electrodeposited electrodes in 0.01M NaCl aqueous solutions containing 0.01M HCl. It was found that performance degradation of the ITO electrodes toward the reduction of Cr(VI) can be suppressed by modifying the electrode surface with gold nanoparticles (AuNPs), which were formed on ITO electrodes by potential-sweeping or potential-step electrodeposition in a 0.01M Na2SO4 solution containing 1mM HAuCl4·3H2O and 0.01M H2SO4. After the modification, the surface of ITO electrodes turned to the characteristically red or blue color exhibited by AuNPs. The gold nanoparticle-electrodeposited indium-tinoxide electrode (AuNP-ITO) demonstrates unique catalytic behavior, higher sensitivity and stability in the reduction of Cr(VI). Cr(VI) species was detected by either cyclic voltammetry or hydrodynamic amperometry. By cyclic voltammetry, the dependence of cathodic peak current on concentration was linear from 5 to 100μM with a detection limit of 2μM (σ =3), and linearity was obtained from 0.5 to 50μM by hydrodynamic amperometry where a constant potential of +0.2V (vs. Ag/AgCl) was applied and a batch-injection cell was employed. For hydrodynamic amperometry, the detection limit was 0.1μM (σ =3). [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
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47. Dicyanamide anion based ionic liquids for electrodeposition of metals
- Author
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Deng, Ming-Jay, Chen, Po-Yu, Leong, Tin-Iao, Sun, I-Wen, Chang, Jeng-Kuei, and Tsai, Wen-Ta
- Subjects
- *
IONIC liquids , *ALUMINUM , *NICKEL , *ZINC - Abstract
Abstract: Electrodeposition of Al, Mn, Ni, Zn, Sn, and Cu are successfully demonstrnated in the ionic liquids (ILs) composed of 1-methyl-3-alkylimidazolium or N-methyl-N-alkylpyrrolidinium cations with dicyanamide (DCA) anions. The DCA-based room-temperature ILs exhibit lower viscosities than those ILs based on , , and bis(trifluoromethylsulfonyl)imide (TFSI) anions. While most of the metal chlorides are insoluble in the , , and TFSI-based ILs, they exhibit good solubility in DCA-based ILs due to the strong complexing ability of DCA toward the transition metal ions. It is possible to alter the regular reduction sequence for particular metal ions in the DCA-based ILs. [Copyright &y& Elsevier]
- Published
- 2008
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48. Biological materials: Structure and mechanical properties
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Meyers, Marc André, Chen, Po-Yu, Lin, Albert Yu-Min, and Seki, Yasuaki
- Subjects
- *
BIOLOGY , *COMPOSITE materials , *MATERIALS , *PROTEINS , *ORGANIC compounds - Abstract
Abstract: Most natural (or biological) materials are complex composites whose mechanical properties are often outstanding, considering the weak constituents from which they are assembled. These complex structures, which have risen from hundreds of million years of evolution, are inspiring Materials Scientists in the design of novel materials. Their defining characteristics, hierarchy, multifunctionality, and self-healing capability, are illustrated. Self-organization is also a fundamental feature of many biological materials and the manner by which the structures are assembled from the molecular level up. The basic building blocks are described, starting with the 20 amino acids and proceeding to polypeptides, polysaccharides, and polypeptides–saccharides. These, on their turn, compose the basic proteins, which are the primary constituents of ‘soft tissues’ and are also present in most biominerals. There are over 1000 proteins, and we describe only the principal ones, with emphasis on collagen, chitin, keratin, and elastin. The ‘hard’ phases are primarily strengthened by minerals, which nucleate and grow in a biomediated environment that determines the size, shape and distribution of individual crystals. The most important mineral phases are discussed: hydroxyapatite, silica, and aragonite. Using the classification of Wegst and Ashby, the principal mechanical characteristics and structures of biological ceramics, polymer composites, elastomers, and cellular materials are presented. Selected systems in each class are described with emphasis on the relationship between their structure and mechanical response. A fifth class is added to this: functional biological materials, which have a structure developed for a specific function: adhesion, optical properties, etc. An outgrowth of this effort is the search for bioinspired materials and structures. Traditional approaches focus on design methodologies of biological materials using conventional synthetic materials. The new frontiers reside in the synthesis of bioinspired materials through processes that are characteristic of biological systems; these involve nanoscale self-assembly of the components and the development of hierarchical structures. Although this approach is still in its infancy, it will eventually lead to a plethora of new materials systems as we elucidate the fundamental mechanisms of growth and the structure of biological systems. [Copyright &y& Elsevier]
- Published
- 2008
- Full Text
- View/download PDF
49. Electrochemical study and electrodeposition of manganese in the hydrophobic butylmethylpyrrolidinium bis((trifluoromethyl)sulfonyl)imide room-temperature ionic liquid
- Author
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Deng, Ming-Jay, Chen, Po-Yu, and Sun, I-Wen
- Subjects
- *
RHEOLOGY , *ELECTRODES , *OPTICAL diffraction , *OPTICS - Abstract
Abstract: The electrochemistry of manganese was investigated at solid disk electrodes in the hydrophobic room-temperature ionic liquid butylmethylpyrrolidinium bis((trifluoromethyl)sulfonyl)imide (BuMePy-TFSI) by using staircase cyclic voltammetry and chronoamperometry. The Mn(II) species was introduced into the ionic liquid by anodic dissolution of the metallic manganese electrode. The reduction of Mn(II) ions at tungsten and platinum electrodes accompanies with nucleation mechanism and the coupled oxidation wave encounters kinetic hindrance that results in incomplete reoxidation of Mn electrodeposits. The density and absolute viscosity of BuMePy-TFSI were measured over a temperature range from 301.0 to 348.0K. A polynomial equation describing the temperature dependence of the density is presented. The viscosity exhibits the Arrhenius temperature dependence and the relevant equation is provided. The manganese coatings were prepared by electrodeposition at several substrates. The surface morphology and X-ray diffraction patterns of these deposits were studied by scanning electron microscopy and powder X-ray diffraction spectroscopy, respectively. The as-electrodeposited manganese coatings were amorphous; however, α-phase manganese was observed after the deposits were annealed under 723K for 1 day. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
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50. The assessment of removing strontium and cesium cations from aqueous solutions based on the combined methods of ionic liquid extraction and electrodeposition
- Author
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Chen, Po-Yu
- Subjects
- *
CATIONS , *SOLUTION (Chemistry) , *ORGANIC compounds , *ELECTRONS - Abstract
Abstract: The extraction of Sr2+ and Cs+ from aqueous solutions by using the ionophores dicyclohexano-18-crown-6 (DCH18C6) and calix[4]arene-bis(tert-octylbenzo-crown-6) (BOBCalixC6), respectively, was demonstrated in the hydrophobic, room-temperature ionic liquid (RTIL), tri-1-butylmethylammonium bis((trifluoromethyl)sulfonyl)imide (Bu3MeN-TFSI). The water contents of several hydrophobic ionic liquids and the absorption/desorption reversibility of oxygen and moisture in the Bu3MeN-TFSI ionic liquid were determined by electrochemical techniques. The relationship between the distribution coefficient, D M, and the concentration ratios of C ionophore,IL/C metal ion,aq were investigated. The values of D M increase with increasing the concentration ratios and they are also influenced with the counter ions of Sr2+ and Cs+ in the aqueous solutions. In the previous study, it was demonstrated that the Sr2+ and Cs+ cations in the Bu3MeN-TFSI ionic liquid could be coordinated by DCH18C6 and BOBCalixC6, respectively, and formed the DCH18C6·Sr2+ and BOBCalixC6·2Cs+ ions, which would be cathodically reduced to Sr- and Cs-amalgam at a mercury film electrode (MFE). In this study, the probability was evaluated if the Sr2+ and Cs+ cations extracted from the aqueous solutions can be really reduced to respective amalgam. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
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