Residual empirical processes for nearly unstable long-memory time series

Ngai Hang Chan,Wei Wei Liu 한국통계학회 2010 Journal of the Korean Statistical Society Vol.39 No.3

This paper studies the goodness-of-fit test of the residual empirical process of a nearly unstable long-memory time series. Chan and Ling (2008) showed that the usual limit distribution of the KolmogorovSmirnov test statistics does not hold for an unstable autoregressive model. A key question of interest is what happens when this model has a near unit root, that is, when it is nearly unstable. In this paper, it is established that the statistics proposed by Chan and Ling can be generalized to encompass nearly unstable long-memory models. In particular, the limit distribution is expressed as a functional of an OrnsteinUhlenbeck process that is driven by a fractional Brownian motion. Simulation studies demonstrate that the limit distribution of the statistic possesses desirable finite sample properties and power.

2022 Taiwan clinical multicenter expert consensus and recommendations for thyroid radiofrequency ablation

Wei-Che Lin,Wen-Chieh Chen,Pei-Wen Wang,Yi-Chia Chan,Yen-Hsiang Chang,Harn-Shen Chen,Szu-Tah Chen,Wei-Chih Chen,Kai-Lun Cheng,Shun-Yu Chi,Pi-Ling Chiang,Chen-Kai Chou,Feng-Fu Chou,Shun-Chen Huang,Feng 대한초음파의학회 2023 ULTRASONOGRAPHY Vol.42 No.3

Radiofrequency ablation (RFA) is a minimally invasive management strategy that has been widely applied for benign and recurrent malignant thyroid lesions as an alternative to surgery in Taiwan. Members of academic societies for specialists in interventional radiology, endocrinology, and endocrine surgery collaborated to develop the first consensus regarding thyroid RFA in Taiwan. The modified Delphi method was used to reach a consensus. Based on a comprehensive review of recent and valuable literature and expert opinions, the recommendations included indications, pre-procedural evaluations, procedural techniques, post-procedural monitoring, efficacy, and safety, providing a comprehensive review of the application of RFA. The consensus effectively consolidates advice regarding thyroid RFA in clinical practice for local experts.

Error Analysis of Multidimensional Evaluation of Pilot’s Workload Based on Objective Measures

Chan Wei,Liming Wei,Zhengxiang Cai,Yanyu Lu,Qi Wu,Dan Huang,Shan Fu 제어로봇시스템학회 2015 제어로봇시스템학회 국제학술대회 논문집 Vol.2015 No.10

Evaluation of pilot’s workload during flight is a significant consideration for the safety of civil aviation. However, some errors may be brought in the measurement and the recording of objective parameters. Based on a multidimensional workload evaluation, the time delay of cardiac activity and its impacts on workload are analyzed. The results suggest that within a certain limit of error around 10s, varying from individual to individual, workload can keep the main information compared to the original workload. As the error increases, the workload may become unreliable. As a consequence, the time-delay error of cardiac activity should be controlled in a limited scale to ensure the validity and reliability of workload.

Computational Efficiency of Meshfree Methods with Local-Coordinates Algorithm

Wei Xuan Chan,손흥선,윤용진 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

In this study, meshfree methods with uniform nodal distribution and local-coordinates shape functions are investigated. The proposedmeshfree method can be used with various shape functions and is tested on a test patch with a Laplace governing equation and bothessential and Neumann boundary conditions. It is shown to reduce the computational time dependency on the number of nodes by36%. This reduction of dependency is significant as it reduces the computational time by several orders for analysis of problemsrequiring very fine nodal distribution. The meshfree method with uniform nodal distribution and local coordinates shape functionreduces and converges to the perfectly uniform nodal distribution with finer nodal distributions. The technique is illustrated on arectangular Kirchhoff-Love plate to show the practical use of the technique for allowing higher order shape function and finer nodaldistribution to be used with multiple overlapping boundary conditions as well as on an electromagnetic problem to explain the usesof this technique on solving multiple similar problem cases with slight changes in geometry of boundary nodes. Overall, the presentmethodology provides a simple way to increase the computational efficiency of meshfree methods in range of an order while retainingmany of its benefits.

Neutralizing Chimeric Mouse-human Antibodies against Burkholderia pseudomallei Protease: Expression, Purification and Characterization

Chan, Shzu-Wei,Ong, Guan-Im,Nathan, Sheila Korean Society for Biochemistry and Molecular Biol 2004 Journal of biochemistry and molecular biology Vol.37 No.5

A recombinant Fab monoclonal antibody (Fab) C37, previously obtained by phage display and biopanning of a random antibody fragment library against Burkholderia pseudomallei protease, was expressed in different strains of Escherichia coli. E. coli strain HB2151 was deemed a more suitable host for Fab expression than other E. coli strains when grown in media supplemented with 0.2% glycerol. The expressed Fab fragment was purified by affinity chromatography on a Protein G-Sepharose column, and the specificity of the recombinant Fab C37 towards B. pseudomallei protease was proven by Western blotting, enzyme-linked immunosorbent assay (ELISA) and by proteolytic activity neutralization. In addition, polyclonal antibodies against B. pseudomallei protease were produced in rabbits immunized with the protease. These were isolated from high titer serum by affinity chromatography on recombinant-Protein A-Sepharose. Purified polyclonal antibody specificity towards B. pseudomallei protease was proven by Western blotting and ELISA.

Curved-quartic-function elements with end-springs in series for direct analysis of steel frames

Si-Wei Liu,Jake Lok Yan Chan,Rui Bai,Siu-Lai Chan 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.29 No.5

A robust element is essential for successful design of steel frames with Direct analysis (DA) method. To this end, an innovative and efficient curved-quartic-function (CQF) beam-column element using the fourth-order polynomial shape function with end-springs in series is proposed for practical applications of DA. The member initial imperfection is explicitly integrated into the element formulation, and, therefore, the <i>P</i>-<i>δ</i> effect can be directly captured in the analysis. The series of zero-length springs are placed at the element ends to model the effects of semi-rigid joints and material yielding. One-element-per-member model is adopted for design bringing considerable savings in computer expense. The incremental secant stiffness method allowing for large deflections is used to describe the kinematic motion. Finally, several problems are studied in this paper for examining and validating the accuracy of the present formulations. The proposed element is believed to make DA simpler to use than existing elements, which is essential for its successful and widespread adoption by engineers.

Neutralizing Chimeric Mouse-human Antibodies against Burkholderia pseudomallei Protease: Expression, Purification and Characterization

( Shzu Wei Chan ),( Guan Im Ong ),( Sheila Nathan ) 생화학분자생물학회 2004 BMB Reports Vol.37 No.5

A recombinant Fab monoclonal antibody (Fab) C37, previously obtained by phage display and biopanning of a random antibody fragment library against Burkholderia pseudomallei protease, was expressed in different strains of Escherichia coli. E. coli strain HB2151 was deemed a more suitable host for Fab expression than other E. coli strains when grown in media supplemented with 0.2% glycerol. The expressed Fab fragment was purified by affinity chromatography on a Protein G-Sepharose column, and the specificity of the recombinant Fab C37 towards B. pseudomallei protease was proven by Western blotting, enzyme-linked immunosorbent assay (ELISA) and by proteolytic activity neutralization. In addition, polyclonal antibodies against B. pseudomallei protease were produced in rabbits immunized with the protease. These were isolated from high titer serum by affinity chromatography on recombinant-Protein A-Sepharose. Purified polyclonal antibody specificity towards B. pseudomallei protease was proven by Western blotting and ELISA.

A Short Review on the Chemistry, Pharmacological Properties and Patents of Obovatol and Obovatal (Neolignans) from Magnolia obovata

Eric Wei Chiang Chan,Siu Kuin Wong,Hung Tuck Chan 한국생약학회 2021 Natural Product Sciences Vol.27 No.3

This short review on the chemistry, pharmacological properties and patents of obovatol and obovatal from Magnolia obovata is the first publication. Pharmacological properties are focused on anti-cancer, anti-inflammatory, anti-platelet and neuroprotective activities. Obovatol and obovatal were first isolated from the leaves of M. obovata. Also reported in the bark and fruits of M. obovata, obovatol and obovatal are neolignans i.e., biphenolic compounds bearing a C‒O coupling. Other classes of compounds isolated and identified from M. obovata include sesquiterpene-neolignans, dineolignans, trineolignan, lignans, dilignans, phenylpropanoids, phenylethanoid glycosides, flavonoids, phenolic acids, alkaloids, sesquiterpenes, ketone and sterols. The anti-cancer properties of obovatol and obovatal involve apoptosis, inhibition of the growth, migration and invasion of cancer cell lines. However, obovatol displays cytotoxicity against cancer cells but not obovatal. Similarly, anti-inflammatory, anti-platelet, neuroprotective, anxiolytic and other pharmacological activities were only observed in obovatol. The disparity in pharmacological properties of obovatol and obovatal may be attributed to the ‒CHO group present in obovatal but absent in obovatol. From 2007 to 2013, eight patents were published on obovatol with one mentioning obovatal. They were all published at the U.S. Patent and Trademark Office by scientists of the Korea Research Institute of Bioscience and Biotechnology (KRIBB) as inventors and assignee, respectively. Some future research and prospects are suggested.

Safety of Pedicle Screws in Adolescent Idiopathic Scoliosis Surgery

Chris Yin Wei Chan,Mun Keong Kwan 대한척추외과학회 2017 Asian Spine Journal Vol.11 No.6

To review existing publications on the safety of pedicle screw insertions in adolescent idiopathic scoliosis (AIS). Despite having increased risk for neurological and visceral injuries, the use of pedicle screws have led to increased correction rates in scoliosis surgery. A review was performed on topics pertinent to pedicle screw insertion in AIS, which included pedicle morphometry in AIS, structures at risk during pedicle screw insertion, and accuracy and safety of various pedicle screw insertion techniques. The importance of computer navigation and future research regarding pedicle screw placement in AIS were also briefly reviewed. Many authors have reported abnormal pedicle anatomy in AIS. Injury to the neural structures was highest over the apical region, whereas aortic injury was the highest at T5 and T10. In the proximal thoracic spine, the esophagus could be injured even with screws as short as 25 mm. Overall pedicle perforation rates for perforations >0 and >2 mm (assessed by computed tomography) ranged from 6.4% to 65.0% and 3.7% to 29.9%, respectively. The critical pedicle perforation (>2 mm excluding lateral thoracic) and anterior perforation (>0 mm) rates was reported to range from 1.5% to 14.5% and 0.0% to 16.1%, respectively. Pedicle perforation rates were lower with the use of computer navigation. The incidence of neurological adverse events after scoliosis surgery was 0.06%–1.9%. Aortic injury has only been observed in case reports. According to the available literature, pedicle screw insertion in AIS is considered safe with low rates of clinical adverse events. Moreover, the use of navigation technology has been shown to reduce pedicle perforation rates.

APSS-ASJ Best Clinical Research Award: Is There a Difference between Patients’ and Parents’ Perception of Physical Appearance in Adolescent Idiopathic Scoliosis?

Chris Yin Wei Chan,Siti Mariam Abd Gani,Min Yuen Lim,Chee Kidd Chiu,Mun Keong Kwan 대한척추외과학회 2019 Asian Spine Journal Vol.13 No.2

Study Design: Prospective study. Purpose: To compare patients’ and parents’ perceptions of physical attributes (PAs) of adolescent idiopathic scoliosis (AIS) patients and to report any correlations between their perceptions and Scoliosis Research Society-22r (SRS-22r) scores. Overview of Literature: Few studies have looked into the differences between patients’ and parents’ perceptions of their appearance. Methods: AIS patient–parent pairs (n=170) were recruited. The patients’ and parents’ perceptions of six PAs were evaluated: waist asymmetry (WA), rib hump (RH), shoulder asymmetry (SA), neck tilt, breast asymmetry (BrA), and chest prominence. These PAs were ranked, and an aggregate PA (Agg-PA) score was derived from a score assigned to the attribute (6 for the most important PA and 1 for the least important). The patients also completed the SRS-22r questionnaire. Results: Ninety-nine patients (58.2%) and 71 patients (41.8%) had thoracic and lumbar major curves, respectively. WA was ranked first by 54 patients (31.8%) and 50 parents (29.4%), whereas RH was ranked first by 50 patients (29.4%) and 38 parents (22.4%). The overall Agg-PA scores were similar for patients and parents (p>0.05). However, for thoracic major curves (TMCs) >40°, a significant difference was noted between the Agg-PA scores of patients and parents for SA (3.5±1.6 vs. 4.2±1.6, p=0.041) and BrA (3.0±1.6 vs. 2.2±1.3, p=0.006). For TMCs <40°, a significant difference was found between the Agg-PA scores of patients and parents for WA (3.7±1.6 vs. 4.4±1.5, p=0.050). BrA was negatively correlated with total SRS-22r score. Conclusions: There were no significant differences between patients and parents in their ranking of the most important PAs. For TMCs >40°, there were significant differences in the Agg-PA for SA and BrA. Pa¬tients were more concerned about BrA and parents were more concerned about SA. Patients’ perception of the six PAs had weak correlation with SRS-22r scores.