Treatment Response Evaluation by Computed Tomography Pulmonary Vasculature Analysis in Patients With Chronic Thromboembolic Pulmonary Hypertension

Yu-Sen Huang,Zheng-Wei Chen,Wen-Jeng Lee,Cho-Kai Wu,Ping-Hung Kuo,Hsao-Hsun Hsu,Shu-Yu Tang,Cheng-Hsuan Tsai,Mao-Yuan Su,Chi-Lun Ko,Juey-Jen Hwang,Yen-Hung Lin,Yeun-Chung Chang The Korean Society of Radiology 2023 Korean Journal of Radiology Vol.24 No.4

Objective: To quantitatively assess the pulmonary vasculature using non-contrast computed tomography (CT) in patients with chronic thromboembolic pulmonary hypertension (CTEPH) pre- and post-treatment and correlate CT-based parameters with right heart catheterization (RHC) hemodynamic and clinical parameters. Materials and Methods: A total of 30 patients with CTEPH (mean age, 57.9 years; 53% female) who received multimodal treatment, including riociguat for ≥ 16 weeks with or without balloon pulmonary angioplasty and underwent both non-contrast CT for pulmonary vasculature analysis and RHC pre- and post-treatment were included. The radiographic analysis included subpleural perfusion parameters, including blood volume in small vessels with a cross-sectional area ≤ 5 mm² (BV5) and total blood vessel volume (TBV) in the lungs. The RHC parameters included mean pulmonary artery pressure (mPAP), pulmonary vascular resistance (PVR), and cardiac index (CI). Clinical parameters included the World Health Organization (WHO) functional class and 6-minute walking distance (6MWD). Results: The number, area, and density of the subpleural small vessels increased after treatment by 35.7% (P < 0.001), 13.3% (P = 0.028), and 39.3% (P < 0.001), respectively. The blood volume shifted from larger to smaller vessels, as indicated by an 11.3% increase in the BV5/TBV ratio (P = 0.042). The BV5/TBV ratio was negatively correlated with PVR (r = -0.26; P = 0.035) and positively correlated with CI (r = 0.33; P = 0.009). The percent change across treatment in the BV5/TBV ratio correlated with the percent change in mPAP (r = -0.56; P = 0.001), PVR (r = -0.64; P < 0.001), and CI (r = 0.28; P = 0.049). Furthermore, the BV5/TBV ratio was inversely associated with the WHO functional classes I-IV (P = 0.004) and positively associated with 6MWD (P = 0.013). Conclusion: Non-contrast CT measures could quantitatively assess changes in the pulmonary vasculature in response to treatment and were correlated with hemodynamic and clinical parameters.

Scale Development and Model Validation for the Process of Exercise Engagement for People with Prediabetes

Chang, Shu-Chuan,Yeh, Hsiu-Chen,Kuo, Yu-Lun 한국간호과학회 2020 Journal of Korean Academy of Nursing Vol.50 No.2

Design of disk cam mechanisms with a translating follower having symmetrical double-concave faces

Yu-Hsuan Chuang,Kuan-Lun Hsu,Wen-Tung Chang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.8

This paper presents an analytical approach for designing disk cam mechanisms with an improved translating follower having symmetrical double-concave faces. The doubleconcave faces of such a follower can increase the actual contact area between the cam and the follower. Additionally, during the dwell periods of the follower motion, both the concave faces of the follower can simultaneously contact the cam profile so as to share the carried loading. Such beneficial characteristics can result in a lower level of contact stress between the cam and the follower. Numerical examples are provided to illustrate the nature and the advantage of this improved follower.

Developing a General Model for Construction Problem Solving for an Engineering Consulting Firm

Pei-Lun Chang,Wen-der Yu 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.6

This paper presents the development of a lessons-learned-based general construction problem-solving model, namely GCPM, within an engineering consulting firm to assist construction engineers in finding the preliminary solution for a construction problem. The proposed GCPM is developed using an induction method based on 631 historical lesson-learned files collected from a leading engineering consulting firm in Taiwan. Elements of the Construction Project Management Body of Knowledge (CPMBOK) of the Project Management Institute (PMI), Theory of Inventive Problem Solving (TRIZ) and Data Mining (DM), are adopted so that the Management Parameters (MPs) and Problem-Solving Principles (PSPs) are defined and derived. Finally, a Construction Problem- Solving Matrix (CPSM) is obtained comprising of two types of MPs and a set of 76 PSPs. After tested with 54 real world cases, the proposed GCPM is verified to achieve 96.5% overall successful application rate. It is concluded that the proposed GCPM provides a promising tool for construction engineers of engineering consultants to direct appropriate problem-solving principles regardless of the complexity and diversity of construction problems.

Investigations on Predictions and Characteristics of Flow Field in the Pipelines of Chillers for Measured Locations of Ultrasonic Flowmeters by CFD Approach

Min-Lun Chai,Yu-Hsuan Chang,Chih-Hung Lin,Jin-Cyuan Tsai,Jhen-You Chin,Ratna Nur Inten 대한설비공학회 2021 International Journal Of Air-Conditioning and Refr Vol.29 No.2

The flow velocity profiles in most of the central air-conditioning pipelines are, in general, not fully developed flow and difficult to obtain the accurate flow rates by flowmeters, which are used for measuring average velocity. Especially for being at the outlet of an elbow, the accuracy of flow rate by measurement is quite low. Therefore, there are some limitations for measurements of flow rate and velocity profile by the present flow measuring technologies. The objective of this study was to establish an approach on accurate predictions of velocity profiles at different measured locations of central air-conditioning pipelines for nonuniform flow measurements by simulations of computational Fluid Dynamics (CFD). All the velocity profiles will integrate as a database for predictions by neural network algorithm for smart measurement further. In the present work initially, international experiments were employed to validate the accuracy of CFD approach. The calculations were carried out by different turbulence models. The results compared with the experimental data by Realizable k-ε turbulence model with less computing resources have great agreements. Realizable k-ε turbulence model was, therefore, determined for the predictions of central air-conditioning pipeline. According to various pipings and pipe sizes, the results for three cases show that the velocity profiles in the pipelines would not be symmetrical and has strong secondary flow. Therefore, all of the flow profiles would be integrated and analyzed as a database and assist to get accurately the measured locations of ultrasonic flowmeters. Further, this database will be combined with algorithm of artificial neural network for smart predictions.

The Effectiveness of Position Limits: Evidence from the Foreign Exchange Futures Markets

Ya-Kai Chang,Yu-Lun Chen,Robin K. Chou 한국재무학회 2012 한국재무학회 학술대회 Vol.2012 No.09

To test the effectiveness of position limits, this study examines the impact of the relative size of hedger and speculator open interests on the price discovery process in both JPY-USD and EUR-USD futures markets. Hedging trading has a negative impact, regardless of its size, on price discovery in futures markets. Hedgers are less likely to be information motivated, so their trading uniformly delays the price discovery process. However, there is a positive and nonlinear impact of speculators’ trade size on price discovery, the contribution of which depends on the relative size of the speculative open interest. Contrary to conventional wisdom among regulators, speculative trading does not harm the market in terms of price discovery; more important, as long as speculative trading is lower than an endogenously determined threshold, it even improves futures market efficiency.

Synthesis of mesoporous SiO2 xerogel/chitosan mixed-matrix membranes for butanol dehydration

Yi-Feng Lin,Chang-Yu Wu,Ting-Yu Liu,Kun-Yi Andrew Lin,Kuo-Lun Tung,Tsair-Wang Chung 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.57 No.-

Novel mesoporous SiO2 xerogel/chitosan (CS) mixed-matrix membranes (MMMs) were successfully prepared by incorporating sol–gel synthesized SiO2 xerogels into glutaraldehyde (GA) cross-linked CS membranes. The effects of the SiO2 doping amount and the feed temperature on the performance of the separation of butanol and water was also investigated in this study. The 0.25 wt% SiO2 xerogel/CS MMMs possessed the best pervaporation performance and the largest PSI value of 1102 kg/m2h with a permeate flux of 736 g/m2h (Permeability of 3.25 × 10−5 g m m−2 h −1 Pa−1) and a separation factor of 1498 at a feed temperature of 50 °C. This PSI value is not only comparable but also exceeds that of other membranes reported in the literature. The separation factor and the flux of the SiO2 xerogel/CS MMMs in this study clearly exceed the upper limit of the previously reported MMMs. As a result, the as-prepared novel SiO2 xerogel/CS MMMs showed an improved performance during the butanol and water separation process, which raises the possibility of future pervaporation applications using this novel SiO2 xerogel/CS MMMs.

Preparation and characterization of superhydrophobic coatings

Hsing-I Hsiang,Ming-Tsai Liang,Yu-Lun Chang,Hung-Chin Huang,Fu-Su Yen 한양대학교 세라믹연구소 2010 Journal of Ceramic Processing Research Vol.11 No.3

To obtain a surface with water-repelling and self-cleaning abilities attracts much interest in the nanotechnology age. In this study, a perfluroalkyl surfactant (perflurodecanoic acid, PFDA) was coated on nano-sized boehmite surfaces to obtain hydrophobic nano-particles via surface modification. Then the hydrophobic boehmite was coated on a transparent plastic film using spin-coating to obtain a hydrophobic film. The effects of various amounts of hydrophobic polymer on the adsorption behavior and contact angle for hydrophobic properties were investigated using FTIR, and a contact-angle meter. The adsorption of PFDA onto the surface of boehmite takes place through ionic bonding. The contact angles of the thin film prepared by spin coating PFDA-modified-boehmite on glass substrates were above 150o as the adsorption of PFDA onto the surface of boehmite reached saturation.

Evaluation of Malignancy Risk of Ampullary Tumors Detected by Endoscopy Using 2-[18F]FDG PET/CT

Chuang Pei-Ju,Wang Hsiu-Po,Tien Yu-Wen,Chin Wei-Shan,Hsieh Min-Shu,Chen Chieh-Chang,Hong Tzu-Chan,Ko Chi-Lun,Wu Yen-Wen,Cheng Mei-Fang 대한영상의학회 2024 Korean Journal of Radiology Vol.25 No.3

Objective: We aimed to investigate whether 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (2-[18F]FDG PET/CT) can aid in evaluating the risk of malignancy in ampullary tumors detected by endoscopy. Materials and Methods: This single-center retrospective cohort study analyzed 155 patients (79 male, 76 female; mean age, 65.7 ± 12.7 years) receiving 2-[18F]FDG PET/CT for endoscopy-detected ampullary tumors 5–87 days (median, 7 days) after the diagnostic endoscopy between June 2007 and December 2020. The final diagnosis was made based on histopathological findings. The PET imaging parameters were compared with clinical data and endoscopic features. A model to predict the risk of malignancy, based on PET, endoscopy, and clinical findings, was generated and validated using multivariable logistic regression analysis and an additional bootstrapping method. The final model was compared with standard endoscopy for the diagnosis of ampullary cancer using the DeLong test. Results: The mean tumor size was 17.1 ± 7.7 mm. Sixty-four (41.3%) tumors were benign, and 91 (58.7%) were malignant. Univariable analysis found that ampullary neoplasms with a blood-pool corrected peak standardized uptake value in earlyphase scan (SUVe) ≥ 1.7 were more likely to be malignant (odds ratio [OR], 16.06; 95% confidence interval [CI], 7.13–36.18; P < 0.001). Multivariable analysis identified the presence of jaundice (adjusted OR [aOR], 4.89; 95% CI, 1.80–13.33; P = 0.002), malignant traits in endoscopy (aOR, 6.80; 95% CI, 2.41–19.20; P < 0.001), SUVe ≥ 1.7 in PET (aOR, 5.43; 95% CI, 2.00–14.72; P < 0.001), and PET-detected nodal disease (aOR, 5.03; 95% CI, 1.16–21.86; P = 0.041) as independent predictors of malignancy. The model combining these four factors predicted ampullary cancers better than endoscopic diagnosis alone (area under the curve [AUC] and 95% CI: 0.925 [0.874–0.956] vs. 0.815 [0.732–0.873], P < 0.001). The model demonstrated an AUC of 0.921 (95% CI, 0.816–0.967) in candidates for endoscopic papillectomy. Conclusion: Adding 2-[18F]FDG PET/CT to endoscopy can improve the diagnosis of ampullary cancer and may help refine therapeutic decision-making, particularly when contemplating endoscopic papillectomy.

Stability Analysis of Perforated Plate Type Single Stage Suspension Fluidized Bed Without Downcomer

Lu, Wei Ming,Ju, Sheau Pyng,Tung, Kuo Lun,Lu, Yu Chang 한국화학공학회 1999 Korean Journal of Chemical Engineering Vol.16 No.6

The stability of operation of a perforated plate type suspension bed without downcomer was analyzed experimentally and numerically. The effects of the feed rate, the gas flowrate and the opening ratio and hole diameter of the perforated plates on the operating stability of the fluidized bed were examined. A full three-dimensional discrete particle simulation method proposed by Tsuji [1993] was performed to study the formation of a stable suspension fluidized bed. The course and behavior of particles that formed a dense and stable fluidized bed are discussed. Both the experimental and simulation results of this study show that the process of forming a suspension bed can be categorized into (i) an induced stage, (ii) a growing stage, and (iii) a stable stage. The velocity of gas through the orifice directly controls the formation of the bed while the solid flow rate over a considerable range maintains a balanced hold-up in the suspension bed system without downcomers. The existence of a multiplicity of steady states corresponding to different gas flow rates, for the same feed rate and perforated plate type, was observed. Results show that the design of the plate, the particle feed rate and the gas velocity distribution through the hole affect the stability of the fluidized bed. The simulated results agree qualitatively well with experimental observations.