36 results on '"Daniel Chong"'
Search Results
2. A southeast Asian perspective on hotel service robots: Trans diagnostic mechanics and conditional indirect effects
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Pradeep Paraman, Sanmugam Annamalah, Srikumar Chakravarthi, Thillai Raja Pertheban, Peter Vlachos, Mohd Farid Shamsudin, Baharudin Kadir, Leong Kuok How, Wong Chee Hoo, Selim Ahmed, Daniel Chong Ka Leong, Murali Raman, and Prakash Singh
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Anthropomorphism ,Hotel service robots ,Service robot acceptance ,Performance expectation ,Perceived threat ,Southeast Asia ,Management. Industrial management ,HD28-70 ,Business ,HF5001-6182 - Abstract
Previous studies have demonstrated how Europeans perceive service robots, but there is a lack of empirical evidence for the same in Asians, particularly from cross-national studies with a substantial sample size. In this study, we adopt a transdiagnostic approach and analyse the disorder caused by hotel service robots (HSR) in the hotel industry using a sample of 1311 respondents from an Asian context. This approach has traditionally been used in psychiatry, and we provide a significant discovery from a Southeast Asian perspective by employing the same methodology.Through the adoption of the methodology used in this study, we recognise that prior research on hotel services has produced uncertain findings, likely due to the presence of multiple service situations. Furthermore, this study is notable because it introduces a methodology that has traditionally been utilized in psychiatry to the field of human-robot management for the first time. Two situational experiments have shown that customers have a preference for highly human-like hotel service robots (HSR), and they believe that these robots perform better in situations where they perceive a high level of control. The effects are only significant in social situations and are reversed when there is a lower perceived level of control. The study's high level of novelty arises from the fact that the effect is absent in luxury hotels within the geographic boundaries of the investigation. These results provide a new outlook on how humans and robots perceive the acceptance of HSR in the hotel industry. Professionals, academics, and hoteliers who are evaluating the decision to implement robots that could either enhance or diminish their service standards may find this study to be valuable.
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- 2023
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3. Benefits from adopting technologies for the hotel’s supply chain management
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Vesna Milovanović, Daniel Chong Ka Leong, and Mihailo Paunović
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information and communications technologies (ICTs) ,supply chain management (SCM) ,hotel ,Hospitality industry. Hotels, clubs, restaurants, etc. Food service ,TX901-946.5 - Abstract
Information and communication technologies (ICTs) have a significant role in contemporary business activities, helping companies to improve quality, efficiency, flexibility and learning capacity, to reduce costs, and finally, to achieve competitive advantage. The aim of this paper is to examine the extent of implementation, as well as the benefits of ICTs used for the hotel supply chain management (SCM). A survey has been conducted involving 40 hotels in Serbia categorized as four- and five-star. The results reveal modest to scanty adoption of SCM-related ICTs among hotels in Serbia. Hotel managers find ICTs they use as very beneficial regarding: (1) more efficient and faster guest attraction, (2) more efficient communication with suppliers, (3) increased speed, (4) increased flexibility, (5) reduced costs and (6) improved guest services. It was also found that the size and affiliation of hotels do not impact the benefits, while the category is positively associated with benefits from using the SCM technologies.
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- 2022
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4. Crossing the bends: Support-catheter based left ventricular lead placement in challenging cardiac resynchronization therapy device implantation
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Amit Kumar Malik, MBBS, MD, Chi Keong Ching, MBBS, MRCP, FAMS, Boon Yew Tan, MBBS, MRCP, Daniel Chong, MBBS, MRCP, and Wee Siong Teo, MBBS, MRCP, FRCP, FACC, FHRS
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Coronary sinus ,Support catheter ,Guide wire ,LV lead ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
The combined use of an Amplatz guiding catheter and support catheter creates a progressively supportive rail to implant the left ventricular (LV) lead in difficult cardiac resynchronization therapy device implantation. We describe the case of a 32-year-old male with non-ischaemic cardiomyopathy, left bundle-branch block, and an LV ejection fraction of 30%, who was referred to our centre for a repeat attempt at an LV lead implant. Previously, the implanter had been unable to advance different guide catheters over the wire to the desired tributary of the coronary sinus (CS). At our centre, the CS was cannulated with a 6-Fr AL2 coronary guiding catheter. A 135-cm support catheter (Spectranetics Quick-Cross) was advanced via AL2 guiding over the 0.035 in. guide wire to the distal CS. The proximal luer fitting of the support catheter was cut and an inner sheath (Medtronic ATTAIN SELECT II) advanced over the support catheter into the CS. A 4-Fr over-the-wire LV lead was advanced through the inner sheath over a 0.014 in. percutaneous transluminal coronary angioplasty wire after removal of the support catheter. The use of a support catheter serves as rail for the placement of the inner sheath deep in the CS and facilitates implantation of the LV pacing lead. This technique is safe and easily applied.
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- 2012
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5. A southeast Asian perspective on hotel service robots: Trans diagnostic mechanics and conditional indirect effects
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Paraman, Pradeep, Annamalah, Sanmugam, Chakravarthi, Srikumar, Pertheban, Thillai Raja, Vlachos, Peter, Shamsudin, Mohd Farid, Kadir, Baharudin, How, Leong Kuok, Chee Hoo, Wong, Ahmed, Selim, Leong, Daniel Chong Ka, Raman, Murali, and Singh, Prakash
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- 2023
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6. Wolff-Parkinson-White Apresentado como QRS Alternante e Outros Diagnósticos Diferenciais em uma Grande Coorte de Triagem de ECG Pré-Participação
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Daniel Y. Z. Lim, Wilbert H. H. Ho, Luokai Wang, Wee Kiat Ang, Nishanth Thiagarajan, Gerald GR Sng, Hankun Wang, Wesley TW Loo, Lim Huai Yang, Weien Chow, Terrance J Chua, Tee Joo Yeo, Paul Lim, and Thuan Tee Daniel Chong
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Síndrome de Wolf-Parkinson-White ,Síndrome do Complexo PR curto-QRS normal ,Pré-Excitação Tipo Mahaim ,Eletrocardiografia/métodos ,Eletrocardiografia/diagnóstico ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Resumo Fundamento A síndrome de Wolff-Parkinson-White (WPW) é uma condição pró-arrítmica que pode exigir restrição de atividades extenuantes e é caracterizada por sinais de ECG, incluindo ondas delta. Observamos casos de padrões intermitentes de WPW apresentando-se como QRS alternante (‘WPW alternante’) em uma grande coorte de triagem de ECG pré-participação de homens jovens que se candidataram ao recrutamento militar. Objetivos Nosso objetivo foi determinar o padrão de WPW alternante, as características do caso e a prevalência de outros diagnósticos diferenciais relevantes apresentando-se como alternância de QRS em um ambiente de pré-participação. Métodos Cento e vinte e cinco mil cento e cinquenta e oito recrutas militares do sexo masculino prospectivos foram revisados de janeiro de 2016 a dezembro de 2019. Uma revisão de prontuários médicos eletrônicos identificou casos de WPW alternante e padrões ou síndrome de WPW. A revisão de prontuários médicos eletrônicos identificou casos de diagnósticos diferenciais relevantes que podem causar alternância de QRS. Resultados Quatro indivíduos (2,2%) apresentaram WPW alternante em 184 indivíduos com diagnóstico final de padrão ou síndrome de WPW. Dois desses indivíduos manifestaram sintomas ou achados eletrocardiográficos compatíveis com taquicardia supraventricular. A prevalência geral de WPW alternante foi de 0,003%, e a prevalência de WPW foi de 0,147%. As WPW alternantes representaram 8,7% dos indivíduos com QRS alternantes, e QRS alternantes tiveram prevalência de 0,037% em toda a população. Conclusões A WPW alternante é uma variante da WPW intermitente, que compreendeu 2,2% dos casos de WPW em nossa coorte de triagem pré-participação. Não indica necessariamente um baixo risco de taquicardia supraventricular. Deve ser reconhecido na triagem de ECG e distinguido de outras patologias que também apresentam QRS alternantes.
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- 2022
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7. TCT-259 Optimal Door-to-Balloon Time for Primary Percutaneous Coronary Intervention for ST-Segment Elevation Myocardial Infarction
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Quan Koh, Samuel Ji, primary, Jiang, Yilin, additional, Lau, Yee How, additional, Yip, James, additional, Liew, Boon Wah, additional, Chia, Pow Li, additional, Loh, Poay Huan, additional, Daniel Chong, Thuan Tee, additional, Patrick Lim, Zhan Yun, additional, Tan, Jack, additional, Sung Lung, Aaron Wong, additional, Yeo, Khung Keong, additional, and Yap, Jonathan, additional
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- 2023
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8. Wolff-Parkinson-White Presenting as QRS Alternans and Other Differential Diagnoses in a Large Pre-Participation ECG Screening Cohort
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Daniel Y. Z. Lim, Wilbert H. H. Ho, Luokai Wang, Wee Kiat Ang, Nishanth Thiagarajan, Gerald GR Sng, Hankun Wang, Wesley TW Loo, Lim Huai Yang, Weien Chow, Terrance J Chua, Tee Joo Yeo, Paul Lim, and Thuan Tee Daniel Chong
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Lown – Ganong – Levine Syndrome ,Pre-Excitation, Mahaim-Type ,Electrocardiography/methods ,Eletrocardiografia/métodos ,Síndrome do Complexo PR curto-QRS normal ,Pré-Excitação Tipo Mahaim ,Wolff-Parkinson-White Syndrome ,Cardiology and Cardiovascular Medicine ,Electrocardiography/diagnosis ,Eletrocardiografia/diagnóstico ,Síndrome de Wolf-Parkinson-White - Abstract
Resumo Fundamento A síndrome de Wolff-Parkinson-White (WPW) é uma condição pró-arrítmica que pode exigir restrição de atividades extenuantes e é caracterizada por sinais de ECG, incluindo ondas delta. Observamos casos de padrões intermitentes de WPW apresentando-se como QRS alternante (‘WPW alternante’) em uma grande coorte de triagem de ECG pré-participação de homens jovens que se candidataram ao recrutamento militar. Objetivos Nosso objetivo foi determinar o padrão de WPW alternante, as características do caso e a prevalência de outros diagnósticos diferenciais relevantes apresentando-se como alternância de QRS em um ambiente de pré-participação. Métodos Cento e vinte e cinco mil cento e cinquenta e oito recrutas militares do sexo masculino prospectivos foram revisados de janeiro de 2016 a dezembro de 2019. Uma revisão de prontuários médicos eletrônicos identificou casos de WPW alternante e padrões ou síndrome de WPW. A revisão de prontuários médicos eletrônicos identificou casos de diagnósticos diferenciais relevantes que podem causar alternância de QRS. Resultados Quatro indivíduos (2,2%) apresentaram WPW alternante em 184 indivíduos com diagnóstico final de padrão ou síndrome de WPW. Dois desses indivíduos manifestaram sintomas ou achados eletrocardiográficos compatíveis com taquicardia supraventricular. A prevalência geral de WPW alternante foi de 0,003%, e a prevalência de WPW foi de 0,147%. As WPW alternantes representaram 8,7% dos indivíduos com QRS alternantes, e QRS alternantes tiveram prevalência de 0,037% em toda a população. Conclusões A WPW alternante é uma variante da WPW intermitente, que compreendeu 2,2% dos casos de WPW em nossa coorte de triagem pré-participação. Não indica necessariamente um baixo risco de taquicardia supraventricular. Deve ser reconhecido na triagem de ECG e distinguido de outras patologias que também apresentam QRS alternantes. Abstract Background Wolff-Parkinson-White (WPW) syndrome is a proarrhythmic condition that may require restriction from strenuous activities and is characterized by ECG signs, including delta waves. We observed cases of intermittent WPW patterns presenting as QRS alternans (‘WPW alternans’) in a large pre-participation ECG screening cohort of young men reporting for military conscription. Objectives We aimed to determine the WPW alternans pattern, case characteristics, and the prevalence of other relevant differential diagnoses presenting as QRS alternans in a pre-participation setting. Methods One hundred twenty-five thousand one hundred fifty-eight prospective male military recruits were reviewed from January 2016 to December 2019. A review of electronic medical records identified cases of WPW alternans and WPW patterns or syndrome. Reviewing electronic medical records identified cases of relevant differential diagnoses that might cause QRS alternans. Results Four individuals (2.2%) had WPW alternans out of 184 individuals with a final diagnosis of WPW pattern or syndrome. Two of these individuals manifested symptoms or ECG findings consistent with supraventricular tachycardia. The overall prevalence of WPW alternans was 0.003%, and the prevalence of WPW was 0.147%. WPW alternans represented 8.7% of individuals presenting with QRS alternans, and QRS alternans had a prevalence of 0.037% in the entire population. Conclusions WPW alternans is a variant of intermittent WPW, which comprised 2.2% of WPW cases in our pre-participation screening cohort. It does not necessarily indicate a low risk for supraventricular tachycardia. It must be recognized at ECG screening and distinguished from other pathologies that also present with QRS alternans.
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- 2022
9. A sub-wavelength Si LED integrated in a CMOS platform
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Zheng Li, Jin Xue, Marc de Cea, Jaehwan Kim, Hao Nong, Daniel Chong, Khee Yong Lim, Elgin Quek, and Rajeev J. Ram
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Multidisciplinary ,General Physics and Astronomy ,General Chemistry ,General Biochemistry, Genetics and Molecular Biology - Abstract
A nanoscale on-chip light source with high intensity is desired for various applications in integrated photonics systems. However, it is challenging to realize such an emitter using materials and fabrication processes compatible with the standard integrated circuit technology. In this letter, we report an electrically driven Si light-emitting diode with sub-wavelength emission area fabricated in an open-foundry microelectronics complementary metal-oxide-semiconductor platform. The light-emitting diode emission spectrum is centered around 1100 nm and the emission area is smaller than 0.14 μm2 (~$$\varnothing 400$$ ∅ 400 nm). This light-emitting diode has high spatial intensity of >50 mW/cm2 which is comparable with state-of-the-art Si-based emitters with much larger emission areas. Due to sub-wavelength confinement, the emission exhibits a high degree of spatial coherence, which is demonstrated by incorporating the light-emitting diode into a compact lensless in-line holographic microscope. This centimeter-scale, all-silicon microscope utilizes a single emitter to simultaneously illuminate ~9.5 million pixels of a complementary metal-oxide-semiconductor imager.
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- 2022
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10. Single-photon avalanche diode fabricated in standard 55 nm bipolar-CMOS-DMOS technology with sub-20 V breakdown voltage
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Won-Yong Ha, Eunsung Park, Doyoon Eom, Hyo-Sung Park, Daniel Chong, Shyue Seng Tan, Michelle Tng, Elgin Quek, Claudio Bruschini, Edoardo Charbon, Woo-Young Choi, and Myung-Jae Lee
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Atomic and Molecular Physics, and Optics - Abstract
This paper presents a single-photon avalanche diode (SPAD) in 55 nm bipolar-CMOS-DMOS (BCD) technology. In order to realize a SPAD having sub-20 V breakdown voltage for mobile applications while preventing high tunneling noise, a high-voltage N-well available in BCD is utilized to implement the avalanche multiplication region. The resulting SPAD has a breakdown voltage of 18.4 V while achieving an excellent dark count rate of 4.4 cps/µm2 at the excess bias voltage of 7 V in spite of the advanced technology node. At the same time, the device achieves a high peak photon detection probability (PDP) of 70.1% at 450 nm thanks to the high and uniform E-field. Its PDP values at 850 and 940 nm, wavelengths of interest for 3D ranging applications reach 7.2 and 3.1%, respectively, with the use of deep N-well. The timing jitter of the SPAD, full width at half maximum (FWHM), is 91 ps at 850 nm. It is expected that the presented SPAD enables cost-effective time-of-flight and LiDAR sensors with the advanced standard technology for many mobile applications.
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- 2023
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11. Determining residents’ enjoyment of Cantonese opera as their performing arts heritage in Macao
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Man-U Io and Daniel Chong
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Cultural Studies ,Social Psychology ,Opera ,media_common.quotation_subject ,05 social sciences ,Geography, Planning and Development ,Visual arts ,Tourism, Leisure and Hospitality Management ,Perception ,0502 economics and business ,050211 marketing ,Performing arts ,Psychology ,050212 sport, leisure & tourism ,media_common - Abstract
This study attempts to empirically investigate Macao residents’ perception and enjoyment of Cantonese opera as their traditional performing arts. By examining the relationship between the experient...
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- 2020
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12. Wolff-Parkinson-White Presenting as QRS Alternans and Other Differential Diagnoses in a Large Pre-Participation ECG Screening Cohort
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Daniel Y Z, Lim, Wilbert H H, Ho, Luokai, Wang, Wee Kiat, Ang, Nishanth, Thiagarajan, Gerald Gr, Sng, Hankun, Wang, Wesley Tw, Loo, Lim Huai, Yang, Weien, Chow, Terrance J, Chua, Tee Joo, Yeo, Paul, Lim, and Thuan Tee Daniel, Chong
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Male ,Diagnosis, Differential ,Electrocardiography ,Tachycardia, Supraventricular ,Humans ,Wolff-Parkinson-White Syndrome ,Prospective Studies - Abstract
Wolff-Parkinson-White (WPW) syndrome is a proarrhythmic condition that may require restriction from strenuous activities and is characterized by ECG signs, including delta waves. We observed cases of intermittent WPW patterns presenting as QRS alternans ('WPW alternans') in a large pre-participation ECG screening cohort of young men reporting for military conscription.We aimed to determine the WPW alternans pattern, case characteristics, and the prevalence of other relevant differential diagnoses presenting as QRS alternans in a pre-participation setting.One hundred twenty-five thousand one hundred fifty-eight prospective male military recruits were reviewed from January 2016 to December 2019. A review of electronic medical records identified cases of WPW alternans and WPW patterns or syndrome. Reviewing electronic medical records identified cases of relevant differential diagnoses that might cause QRS alternans.Four individuals (2.2%) had WPW alternans out of 184 individuals with a final diagnosis of WPW pattern or syndrome. Two of these individuals manifested symptoms or ECG findings consistent with supraventricular tachycardia. The overall prevalence of WPW alternans was 0.003%, and the prevalence of WPW was 0.147%. WPW alternans represented 8.7% of individuals presenting with QRS alternans, and QRS alternans had a prevalence of 0.037% in the entire population.WPW alternans is a variant of intermittent WPW, which comprised 2.2% of WPW cases in our pre-participation screening cohort. It does not necessarily indicate a low risk for supraventricular tachycardia. It must be recognized at ECG screening and distinguished from other pathologies that also present with QRS alternans.A síndrome de Wolff-Parkinson-White (WPW) é uma condição pró-arrítmica que pode exigir restrição de atividades extenuantes e é caracterizada por sinais de ECG, incluindo ondas delta. Observamos casos de padrões intermitentes de WPW apresentando-se como QRS alternante (‘WPW alternante’) em uma grande coorte de triagem de ECG pré-participação de homens jovens que se candidataram ao recrutamento militar.Nosso objetivo foi determinar o padrão de WPW alternante, as características do caso e a prevalência de outros diagnósticos diferenciais relevantes apresentando-se como alternância de QRS em um ambiente de pré-participação.Cento e vinte e cinco mil cento e cinquenta e oito recrutas militares do sexo masculino prospectivos foram revisados de janeiro de 2016 a dezembro de 2019. Uma revisão de prontuários médicos eletrônicos identificou casos de WPW alternante e padrões ou síndrome de WPW. A revisão de prontuários médicos eletrônicos identificou casos de diagnósticos diferenciais relevantes que podem causar alternância de QRS.Quatro indivíduos (2,2%) apresentaram WPW alternante em 184 indivíduos com diagnóstico final de padrão ou síndrome de WPW. Dois desses indivíduos manifestaram sintomas ou achados eletrocardiográficos compatíveis com taquicardia supraventricular. A prevalência geral de WPW alternante foi de 0,003%, e a prevalência de WPW foi de 0,147%. As WPW alternantes representaram 8,7% dos indivíduos com QRS alternantes, e QRS alternantes tiveram prevalência de 0,037% em toda a população.A WPW alternante é uma variante da WPW intermitente, que compreendeu 2,2% dos casos de WPW em nossa coorte de triagem pré-participação. Não indica necessariamente um baixo risco de taquicardia supraventricular. Deve ser reconhecido na triagem de ECG e distinguido de outras patologias que também apresentam QRS alternantes.
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- 2022
13. Identification of an I Na-dependent and I to-mediated proarrhythmic mechanism in cardiomyocytes derived from pluripotent stem cells of a Brugada syndrome patient
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Brian K. Panama, Rita Yu Yin Yong, Dongrui Ma, Boon Yew Tan, Yongxing Zhao, Daniel Chong, Heming Wei, Glenna C.L. Bett, Connie R. Bezzina, Jianjun Wu, James S. Ware, Kah Leng Ho, Chi Keong Ching, Li Jun Loh, Paul Chun Yih Lim, Reginald Liew, Omedul Islam, Stuart A. Cook, Zhenfeng Liu, Arie O. Verkerk, Ying Ying Chung, Wee Siong Teo, Aaron D. Kaplan, Guang Li, Randall L. Rasmusson, Cardiology, ACS - Heart failure & arrhythmias, ACS - Amsterdam Cardiovascular Sciences, and Medical Biology
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Pluripotent Stem Cells ,0301 basic medicine ,medicine.medical_specialty ,Patch-Clamp Techniques ,Cellular differentiation ,lcsh:Medicine ,030204 cardiovascular system & hematology ,Article ,Membrane Potentials ,NAV1.5 Voltage-Gated Sodium Channel ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,medicine ,Humans ,Myocyte ,Repolarization ,Myocytes, Cardiac ,Patch clamp ,Induced pluripotent stem cell ,lcsh:Science ,Brugada Syndrome ,Brugada syndrome ,Membrane potential ,Multidisciplinary ,Chemistry ,Sodium ,lcsh:R ,Cardiac arrhythmia ,Cell Differentiation ,medicine.disease ,030104 developmental biology ,Endocrinology ,Mutation ,Potassium ,lcsh:Q - Abstract
Brugada syndrome (BrS) is an inherited cardiac arrhythmia commonly associated with SCN5A mutations, yet its ionic mechanisms remain unclear due to a lack of cellular models. Here, we used human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from a BrS patient (BrS1) to evaluate the roles of Na+ currents (INa) and transient outward K+ currents (Ito) in BrS induced action potential (AP) changes. To understand the role of these current changes in repolarization we employed dynamic clamp to “electronically express” IK1 and restore normal resting membrane potentials and allow normal recovery of the inactivating currents, INa, ICa and Ito. HiPSC-CMs were generated from BrS1 with a compound SCN5A mutation (p. A226V & p. R1629X) and a healthy sibling control (CON1). Genome edited hiPSC-CMs (BrS2) with a milder p. T1620M mutation and a commercial control (CON2) were also studied. CON1, CON2 and BrS2, had unaltered peak INa amplitudes, and normal APs whereas BrS1, with over 75% loss of INa, displayed a loss-of-INa basal AP morphology (at 1.0 Hz) manifested by a reduced maximum upstroke velocity (by ~80%, p Ito densities of BrS1 and CON1 were comparable and increased from 1.0 Hz to 0.1 Hz by ~ 100%. These data indicate that a repolarization deficit could be a mechanism underlying BrS.
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- 2018
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14. Recurrent shocks from implantable cardiac defibrillator implanted 6 months ago. What is the mechanism?
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Kelvin Wong, Colin Yeo, Thuan Tee Daniel Chong, and Vern Hsen Tan
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inappropriate shocks ,medicine.medical_specialty ,lcsh:Diseases of the circulatory (Cardiovascular) system ,VT ,business.industry ,ICD ,SVT ,Eps for Resident Physicians ,lcsh:RC666-701 ,Internal medicine ,Cardiology ,medicine ,Cardiology and Cardiovascular Medicine ,business ,Mechanism (sociology) - Published
- 2019
15. Exceptional response to vemurafenib and cobimetinib in anaplastic thyroid cancer 40 years after treatment for papillary thyroid cancer
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Electron Kebebew, Richard H. Schwartz, Daniel Chong, Michael Allgauer, Patience Green, and Jasmine Shell
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0301 basic medicine ,Oncology ,Economics and Econometrics ,medicine.medical_specialty ,endocrine system diseases ,Exceptional Response ,Papillary thyroid cancer ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Internal medicine ,Materials Chemistry ,Media Technology ,medicine ,Anaplastic thyroid cancer ,Vemurafenib ,Cobimetinib ,business.industry ,Forestry ,medicine.disease ,030104 developmental biology ,chemistry ,030220 oncology & carcinogenesis ,business ,After treatment ,medicine.drug - Abstract
Case description: We present an unusual case of a patient that developed anaplastic thyroid cancer 40 years after treatment for papillary thyroid cancer. The patient presented with locoregional recurrence and distant metastasis. Tumor genotyping identified a BRAF V600E mutation. The patient was treated with drugs targeting BRAF V600E and MEK (vemurafenib and cobimetinib, respectively). The patient had a remarkable response with the right neck tumor shrinking 81% in size and disappearance of the distant metastases over an 8-month period. The patient underwent surgical resection of the residual tumor with genetic testing of the specimen showing persistent BRAF V600E mutation population of cells. Conclusion: Targeted drug therapy has been used with discretion on a case-by-case basis for anaplastic thyroid cancer and may result in good tumor response.
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- 2017
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16. Patient barriers to implantable cardioverter defi brillator implantation for the primary prevention of sudden cardiac death in patients with heart failure and reduced ejection fraction
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Daniel Chong, Chi Keong Ching, Choon Pin Lim, Kah Leng Ho, David Sim, Laura Lihua Chan, Paul Quetua, Soe Tin Aung, and Wee Siong Teo
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Male ,medicine.medical_specialty ,Multivariate analysis ,medicine.medical_treatment ,030204 cardiovascular system & hematology ,Sudden cardiac death ,03 medical and health sciences ,0302 clinical medicine ,Risk Factors ,Primary prevention ,medicine ,Humans ,In patient ,030212 general & internal medicine ,Heart Failure ,Singapore ,Ejection fraction ,business.industry ,Stroke Volume ,General Medicine ,Middle Aged ,medicine.disease ,Implantable cardioverter-defibrillator ,Defibrillators, Implantable ,Primary Prevention ,Survival Rate ,Cross-Sectional Studies ,Death, Sudden, Cardiac ,Heart failure ,Emergency medicine ,Female ,Original Article ,Implant ,business - Abstract
INTRODUCTION Device therapy is efficacious in preventing sudden cardiac death (SCD) in patients with reduced ejection fraction. However, few who need the device eventually opt to undergo implantation and even fewer reconsider their decisions after deliberation. This is due to many factors, including unresolved patient barriers. This study identified the factors that influenced patients' decision to decline implantable cardioverter defibrillator (ICD) implantation, and those that influenced patients who initially declined an implant to reconsider having one. METHODS A single-centre survey was conducted among 240 patients who had heart failure with reduced ejection fraction and met the ICD implantation criteria, but had declined ICD implantation. RESULTS Participants who refused ICD implantation were mostly male (84%), Chinese (71%), married (72%), currently employed (54%), and had up to primary or secondary education (78%) and monthly income of < SGD 3,000 (51%). Those who were more likely to reconsider their decision were aware that SCD was a consequence of heart failure with reduced ejection fraction, knowledgeable of the preventive role of ICDs, currently employed and aware that their doctor strongly recommended the implant. Based on multivariate analysis, knowledge of the role of ICDs for primary prophylaxis was the most important factor influencing patient decision. CONCLUSION This study identified the demographic and social factors of patients who refused ICD therapy. Knowledge of the role of ICDs in preventing SCD was found to be the strongest marker for reconsidering ICD implantation. Measures to address this information gap may lead to higher rates of ICD implantation.
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- 2016
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17. Abstract B029: Chinese American Pain Experience (CAPE) project: A mixed-methods study to understand cancer-related pain management in Chinese American patients in New York City
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Germaine Cuff, Andrew D. Rosenberg, Jazmine Wong, Chau Trinh-Shevrin, Joan Kelly, Simona Kwon, Qian Chen, Virginia Tong, and Daniel Chong
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Pain experience ,medicine.medical_specialty ,Oncology ,Epidemiology ,business.industry ,Family medicine ,Cape ,Medicine ,business ,Cancer-Related Pain ,Chinese americans - Abstract
Background: Chinese Americans make up the largest subgroup of the Asian American population in the US and are the largest Asian subset in New York City, where the population of Chinese Americans is 547,886; 72% are foreign-born, 34% lack a high school diploma, 61% have limited English proficiency (LEP), and 21% are living in poverty. Cancer is the leading cause of date among Chinese New Yorkers who suffer a disproportionately high burden for specific cancers, including nasopharyngeal, liver, and stomach cancer. Despite this cancer burden, Chinese Americans are at high risk for poorly controlled and managed pain in clinic and hospital settings and under-represented in pain related research. The goal of the CAPE project is to understand the concepts of pain and pain experience and identify potential facilitators and barriers to pain treatment and satisfaction among limited-English-proficient Chinese American inpatients treated at a New York City-based hospital. Methods: Kleinman's Patient's Explanatory Model of Illness and principles of social marketing served as guiding frameworks. In addition, a scoping review was conducted of electronic databases including PubMed, Google Scholar, and the gray literature on the pain management literature for Chinese American patients to further inform the interview topic guide and survey instrument. Key search terms included combinations of “Asian American,” “Chinese,” “Chinese American,” “cancer,” “pain,” “pain management,” and “pain experience.” Chinese American patients who requested services in Chinese language (e.g., Cantonese, Mandarin) will participate in a one-time qualitative interview and survey data collection. A sample of 25 participants will be recruited or until data saturation is achieved. All data collection will be conducted in the patients' preferred language. Analysis of the qualitative data will utilize the techniques of narrative analysis and constant comparison analytic approach. Results: The scoping review identified significant gaps in the extant literature. Findings highlighted the lack of intervention or clinical trial studies to address pain and cancer-related pain management for Chinese American patients despite data confirming high rates of dissatisfaction with pain management in clinic and hospital settings. Qualitative data will be assessed to identify themes related to factors to inform the development of strategies and programs on optimal and cultural relevant pain management. Conclusions: To improve quality of cancer care for Chinese American patients, study findings will inform the cultural adaption of hospital-based pain management programs and services and practice recommendations to facilitate culturally relevant pain treatment for this vulnerable patient population. Citation Format: Simona Kwon, Jazmine Wong, Andrew Rosenberg, Joan Kelly, Virginia Tong, Daniel Chong, Germaine Cuff, Qian Chen, Chau Trinh-Shevrin. Chinese American Pain Experience (CAPE) project: A mixed-methods study to understand cancer-related pain management in Chinese American patients in New York City [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr B029.
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- 2020
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18. First clinical experience of the safety and feasibility of total subcutaneous implantable defibrillator in an Asian population
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Jo-Jo Hai, Kwok-Keung Chan, Wee-Siong Teo, Daniel Chong, Chin-Pang Chan, Boon-Yew Tan, Hung-Fat Tse, Kah-Leng Ho, Eric Tien Siang Lim, Yat-Sun Chan, and Chi Keong Ching
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Male ,medicine.medical_specialty ,Prosthesis-Related Infections ,Ventricular Tachyarrhythmias ,Pilot Projects ,Ischaemic cardiomyopathy ,030204 cardiovascular system & hematology ,Implantable defibrillator ,03 medical and health sciences ,0302 clinical medicine ,Physiology (medical) ,Humans ,Medicine ,030212 general & internal medicine ,Idiopathic ventricular fibrillation ,Retrospective Studies ,Brugada syndrome ,Heart Failure ,High rate ,Singapore ,business.industry ,Equipment Design ,medicine.disease ,Defibrillators, Implantable ,Surgery ,Equipment Failure Analysis ,Death, Sudden, Cardiac ,Treatment Outcome ,Asian population ,Feasibility Studies ,Hong Kong ,Equipment Failure ,Female ,Patient Safety ,Cardiology and Cardiovascular Medicine ,business ,Body mass index - Abstract
Aims The safety and feasibility of a subcutaneous implantable cardioverter-defibrillator (S-ICD) has been demonstrated in the treatment of life-threatening ventricular tachyarrhythmias (VT). Nonetheless, its safety and feasibility in an Asian population with smaller body-build is unclear. Methods and results Twenty-one Asian patients who underwent S-ICD from 1 April 2014 to 2 February 2015 in five institutions in Hong Kong and Singapore were retrospectively reviewed. Twenty-one patients with a mean age of 50.0 ± 14.1 years (range 29–77 years, 82.6% male) were included. Among them, 17 (81.0%) were Chinese, 3 (14.3%) were Malay, and 1 (4.8%) was Indian. Their mean body mass index was 23.0 ± 4.0 kg/m2. An S-ICD was implanted for primary and secondary prevention in 13 (61.9%) and 8 (38.1%) patients, respectively. The indications included Brugada syndrome ( n = 6, 28.6%), ischaemic cardiomyopathy (CMP, n = 6, 28.6%), dilated CMP ( n = 4, 19.0%), hypertrophic CMP ( n = 2, 9.5%), and idiopathic ventricular fibrillation ( n = 2, 9.5%). Three patients (14.3%) had prior infected transvenous ICD. There were no acute complications but eight wound complications (persistent wound bleeding requiring intervention = 2; delayed wound healing: upper sternal wound = 3; generator site = 1; local wound infection = 2) were observed in six (28.2%) patients. After a mean follow-up of 107.2 ± 81.3 days (range of 14–254 days), one patient underwent three successful appropriate shocks for treatment of VTs. No inappropriate therapy was documented. Conclusion Our initial experience shows that S-ICD is a feasible treatment for VT among an Asian population with smaller body-build. There was nonetheless a relatively high rate of wound complications.
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- 2015
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19. Separation of Geraniol from Citronellol by Selective Oxidation of Geraniol to Geranial
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Daniel Chong Jun Weng, Jalifah Latip, Siti Aishah Hasbullah, and Harjono Sastrohamidjojo
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Multidisciplinary - Published
- 2015
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20. Comparison of the Quantitative CT Imaging Biomarkers of Idiopathic Pulmonary Fibrosis at Baseline and Early Change with an Interval of 7 Months
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Hyun J. Kim, Matthew S. Brown, Hak J. Kim, David W. Gjertson, Heidi Coy, Daniel Chong, Peiyun Lu, and Jonathan G. Goldin
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Male ,medicine.medical_specialty ,Vital capacity ,Sensitivity and Specificity ,Severity of Illness Index ,Spearman's rank correlation coefficient ,Idiopathic pulmonary fibrosis ,FEV1/FVC ratio ,DLCO ,Internal medicine ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Longitudinal Studies ,business.industry ,Interstitial lung disease ,Reproducibility of Results ,respiratory system ,medicine.disease ,Idiopathic Pulmonary Fibrosis ,Radiographic Image Enhancement ,Early Diagnosis ,Disease Progression ,Kurtosis ,Cardiology ,Radiographic Image Interpretation, Computer-Assisted ,Female ,sense organs ,Radiology ,Ct imaging ,Tomography, X-Ray Computed ,business - Abstract
Rationale and Objectives Median survival of patients with idiopathic pulmonary fibrosis (IPF) is 2–5 years. Sensitive imaging metrics can play a role in detecting early changes in therapeutic development. The aim of the present study was to compare known computed tomography (CT) histogram kurtosis and a classifier-based quantitative score to assess baseline severity and change over time in patients with IPF. Materials and Methods A total of 57 patients with at least baseline and paired follow-up scans were selected from an imaging database of standardized CT scans obtained from patients with IPF. CT histogram measurement of kurtosis and quantitative lung fibrosis (QLF) and quantitative interstitial lung disease (QILD) scores from a classification algorithm were calculated. Spearman rank correlations were used to assess associations between baseline severity and changes for all CT-derived measures compared to forced vital capacity (FVC) and carbon monoxide diffusion capacity (DLCO) (percent predicted). Results At baseline, mean (±SD) of kurtosis was 2.43 (±1.83). Mean (±SD) values of QLF and QILD scores were 20.7% (±13.4) and 43.3% (±20.0), respectively. All baseline histogram indices and QLF and QILD scores were correlated well with baseline FVC and DLCO. When assessing associations with changes in FVC and DLCO over time, only QLF score was statistically significant (ρ = −0.57; P
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- 2015
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21. Clinical markers of organ dysfunction associated with increased 1-year mortality post-implantable cardioverter defibrillator implantation
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Daniel Chong, Wee Siong Teo, Boon Yew Tan, Kah Leng Ho, Chi Keong Ching, and Reginald Liew
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Male ,Time Factors ,medicine.medical_treatment ,Myocardial Ischemia ,Kaplan-Meier Estimate ,chemistry.chemical_compound ,Risk Factors ,Secondary Prevention ,Medicine ,biology ,Liver Diseases ,Alanine Transaminase ,Anemia ,Dilated cardiomyopathy ,Middle Aged ,Implantable cardioverter-defibrillator ,Defibrillators, Implantable ,Primary Prevention ,Treatment Outcome ,Creatinine ,Cardiology ,Female ,Kidney Diseases ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,Glomerular Filtration Rate ,Cardiomyopathy, Dilated ,medicine.medical_specialty ,Electric Countershock ,Renal function ,Aspartate transaminase ,Risk Assessment ,Disease-Free Survival ,Predictive Value of Tests ,Physiology (medical) ,Internal medicine ,Humans ,Aspartate Aminotransferases ,International Normalized Ratio ,Aged ,Proportional Hazards Models ,Retrospective Studies ,Mechanical ventilation ,Chi-Square Distribution ,business.industry ,Organ dysfunction ,Respiration Disorders ,medicine.disease ,Respiration, Artificial ,Cerebrovascular Disorders ,chemistry ,Alanine transaminase ,Multivariate Analysis ,Prothrombin Time ,biology.protein ,business ,Biomarkers - Abstract
Aims Guidelines from the ESC and ACC/AHA recommend implantable cardioverter defibrillators (ICDs) be implanted in clinically indicated patients with a reasonable expectation of >1 year survival. Our study aimed to assess if selected clinical markers of organ dysfunction were associated with increased 1-year mortality despite ICD therapy. Methods and results We retrospectively studied 283 patients with de novo ICDs implanted for primary or secondary prevention in ischaemic heart disease and dilated cardiomyopathy. We investigated the association of the following clinical markers of organ dysfunction with 1 year mortality: liver dysfunction (aspartate transaminase/alanine transaminase ≥ 3× upper limit of normal or prothrombin time/international normalized ratio ≥ 1.5 in the absence of anticoagulation), respiratory dysfunction (recent mechanical ventilation within 3 months prior to ICD implant), renal dysfunction (creatinine ≥150 µmol/L or glomerular filtration rate ≤ 30 mL/min/1.73 m2), anaemia (Hb ≤ 100 g/L), and prior cerebral vascular injury. With no organ dysfunction, 1 year mortality was 1.9%. In the presence of a single organ dysfunction, mortality was increased to 14.3%. With two or more markers of organ dysfunction mortality was 38.1% at 1 year (log-rank test P < 0.001). Conclusions Clinical markers of liver dysfunction, recent mechanical ventilation, and renal impairment were independently associated with increased 1 year mortality. Presence of more than one clinical marker of organ dysfunction was associated with significantly increased risk of mortality in our study.
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- 2012
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22. Robustness-Driven Feature Selection in Classification of Fibrotic Interstitial Lung Disease Patterns in Computed Tomography Using 3D Texture Features
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Pechin Lo, Hyun J. Kim, Jonathan G. Goldin, Matthew S. Brown, Daniel Chong, Michael F. McNitt-Gray, Fereidoun Abtin, and S Young
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Lung Diseases ,Computer science ,Image Processing ,Pulmonary Fibrosis ,030218 nuclear medicine & medical imaging ,Pattern Recognition, Automated ,Machine Learning ,Computer-Assisted ,Engineering ,0302 clinical medicine ,Pulmonary fibrosis ,Image Processing, Computer-Assisted ,Computer vision ,Honeycombing ,Tomography ,High-resolution computed tomography ,Radiological and Ultrasound Technology ,medicine.diagnostic_test ,Interstitial lung disease ,X-Ray Computed ,Computer Science Applications ,Nuclear Medicine & Medical Imaging ,machine learning ,030220 oncology & carcinogenesis ,Automated ,Feature selection ,Image processing ,Iterative reconstruction ,Pattern Recognition ,03 medical and health sciences ,Information and Computing Sciences ,Parenchyma ,medicine ,Humans ,pattern recognition and classification ,Electrical and Electronic Engineering ,business.industry ,medicine.disease ,Support vector machine ,Normal lung ,Artificial intelligence ,Interstitial ,business ,Lung Diseases, Interstitial ,Tomography, X-Ray Computed ,Classifier (UML) ,fibrotic interstitial lung disease ,Software - Abstract
Lack of classifier robustness is a barrier to widespread adoption of computer-aided diagnosis systems for computed tomography (CT). We propose a novel Robustness-Driven Feature Selection (RDFS) algorithm that preferentially selects features robust to variations in CT technical factors. We evaluated RDFS in CT classification of fibrotic interstitial lung disease using 3D texture features. CTs were collected for 99 adult subjects separated into three datasets: training, multi-reconstruction, testing. Two thoracic radiologists provided cubic volumes of interest corresponding to six classes: pulmonary fibrosis, ground-glass opacity, honeycombing, normal lung parenchyma, airway, vessel. The multi-reconstruction dataset consisted of CT raw sinogram data reconstructed by systematically varying slice thickness, reconstruction kernel, and tube current (using a synthetic reduced-tube-current algorithm). Two support vector machine classifiers were created, one using RDFS ("with-RDFS") and one not ("without-RDFS"). Classifier robustness was compared on the multi-reconstruction dataset, using Cohen's kappa to assess classification agreement against a reference reconstruction. Classifier performance was compared on the testing dataset using the extended g-mean (EGM) measure. With-RDFS exhibited superior robustness (kappa 0.899-0.989) compared to without-RDFS (kappa 0.827-0.968). Both classifiers demonstrated similar performance on the testing dataset (EGM 0.778 for with-RDFS; 0.785 for without-RDFS), indicating that RDFS does not compromise classifier performance when discarding nonrobust features. RDFS is highly effective at improving classifier robustness against slice thickness, reconstruction kernel, and tube current without sacrificing performance, a result that has implications for multicenter clinical trials that rely on accurate and reproducible quantitative analysis of CT images collected under varied conditions across multiple sites, scanners, and timepoints.
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- 2015
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23. Patient barriers to implantable cardioverter defibrillator implantation for the primary prevention of sudden cardiac death in patients with heart failure and reduced ejection fraction.
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Laura Lihua Chan, Choon Pin Lim, Soe Tin Aung, Quetua, Paul, Kah Leng Ho, Daniel Chong, Wee Siong Teo, Sim, David, Chi Keong Ching, Chan, Laura Lihua, Lim, Choon Pin, Aung, Soe Tin, Ho, Kah Leng, Chong, Daniel, Teo, Wee Siong, and Ching, Chi Keong
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IMPLANTABLE cardioverter-defibrillators ,IMPLANTED cardiovascular instruments ,CARDIAC arrest prevention ,HEART failure patients ,MEDICAL decision making ,KNOWLEDGE gap theory ,HEART failure treatment ,COMPARATIVE studies ,HEART failure ,RESEARCH methodology ,MEDICAL cooperation ,PREVENTIVE health services ,RESEARCH ,SURVIVAL ,EVALUATION research ,CROSS-sectional method ,STROKE volume (Cardiac output) - Abstract
Introduction: Device therapy is efficacious in preventing sudden cardiac death (SCD) in patients with reduced ejection fraction. However, few who need the device eventually opt to undergo implantation and even fewer reconsider their decisions after deliberation. This is due to many factors, including unresolved patient barriers. This study identified the factors that influenced patients' decision to decline implantable cardioverter defibrillator (ICD) implantation, and those that influenced patients who initially declined an implant to reconsider having one.Methods: A single-centre survey was conducted among 240 patients who had heart failure with reduced ejection fraction and met the ICD implantation criteria, but had declined ICD implantation.Results: Participants who refused ICD implantation were mostly male (84%), Chinese (71%), married (72%), currently employed (54%), and had up to primary or secondary education (78%) and monthly income of < SGD 3,000 (51%). Those who were more likely to reconsider their decision were aware that SCD was a consequence of heart failure with reduced ejection fraction, knowledgeable of the preventive role of ICDs, currently employed and aware that their doctor strongly recommended the implant. Based on multivariate analysis, knowledge of the role of ICDs for primary prophylaxis was the most important factor influencing patient decision.Conclusion: This study identified the demographic and social factors of patients who refused ICD therapy. Knowledge of the role of ICDs in preventing SCD was found to be the strongest marker for reconsidering ICD implantation. Measures to address this information gap may lead to higher rates of ICD implantation. [ABSTRACT FROM AUTHOR]- Published
- 2016
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24. Brugada Syndrome and SCN5A-Encoded Cardiac Sodium Channel Mutations in Singapore
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Linda Gan, Wei Qi Wong, Boon Yew Tan, Swee Chong Seow, Jia Ling Neo, Rita Yong, Shiao Hui Yap, Daniel Chong, Chi Keong Ching, Wee Siong Teo, Reginald Liew, and Mahesh Uttamchandani
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medicine.medical_specialty ,Pediatrics ,Scn5a gene ,business.industry ,Sodium channel ,medicine.disease ,Compound heterozygosity ,Gastroenterology ,Severe phenotype ,Internal medicine ,Mutation (genetic algorithm) ,medicine ,Population study ,PR interval ,Cardiology and Cardiovascular Medicine ,business ,Brugada syndrome - Abstract
Introduction:This study aims to characterize patients with Brugada syndrome (BrS) in Singapore, and its association with SCN5A-encoded cardiac sodium channel mutations.Methods:The study population consisted of 30 unrelated individuals (28 males, 93%) with either spontaneous or drug induced type 1 coved ST-segment elevation in leads V1–V3.Results:The mean age of symptom onset was 40.8 years (SD 13.5, min 11, max 72). The mean follow up duration was 3.6 years. Nine patients had an ICD implanted, none had appropriate ICD shocks.Mutation in the SCN5A gene was found in 5 out of the 30 individuals (16.7%). The PR interval in SCN5A mutation carriers was significantly prolonged (201.40 +/− 28.35 ms vs 168.92 +/− 27.67 ms, p=0.024). One individual had compound heterozygous mutation and presented with syncope and VT at the age of 11. A total of 6 mutations were identified, four of which were novel (67%).Conclusion:In this study, a mutation in the SCN5A gene was found in 16.7% of patients with BrS. The presence of a SCN5A mutation results in a longer PR interval. Compound heterozygosity in one individual appears to confer a more severe phenotype and an earlier onset of symptoms.
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- 2011
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25. In a Multi-Ethnic Asian ICD Population, Are There Differences in Anti-Tachycardia Pacing Thresholds?
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Daniel Chong, Boon Yew Tan, Reginald Liew, Wee Siong Teo, Aaron Koh, and Chi Keong Ching
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Tachycardia ,education.field_of_study ,medicine.medical_specialty ,business.industry ,medicine.medical_treatment ,Population ,Ethnic group ,Implantable cardioverter-defibrillator ,Internal medicine ,medicine ,Cardiology ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,education ,business - Published
- 2011
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26. Compound Heterozygosity in Brugada Syndrome: A Case Study
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Mahesh Uttamchandani, Linda Gan, Boon Yew Tan, Shiao Hui Yap, Rita Yong, Swee Chong Seow, Daniel Chong, Reginald Liew, Wee Siong Teo, Wei Qi Wong, Jia Ling Neo, and Chi Keong Ching
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medicine.medical_specialty ,business.industry ,Internal medicine ,Medicine ,Cardiology and Cardiovascular Medicine ,Compound heterozygosity ,business ,medicine.disease ,Gastroenterology ,Brugada syndrome - Published
- 2011
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27. Pacing Trends over a Decade in a National Registry
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Chi Keong Ching, Daniel Chong, Ling Ling Sim, Reginald Lie, Malik Amit, Boon Yew Tan, and Wee Siong Teo
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medicine.medical_specialty ,Population ageing ,Pediatrics ,Cardiac pacing ,business.industry ,Heart block ,Mean age ,medicine.disease ,Surgery ,Sick sinus syndrome ,Cardiac procedures ,Epidemiology ,medicine ,National registry ,Cardiology and Cardiovascular Medicine ,business - Abstract
Permanent cardiac pacing is the treatment of choice in patients with symptomatic bradyarrhythmias. The SCDB is a prospective registry of interventional cardiac procedures done in Singapore since July 2000. This report looks at the data from NHC during the period from 2000–2010. There were 1724 pacemakers implanted during the 10 year with almost yearly increase in the number of pacemakers implanted at this single centre. The mean age of the patients was 69.86 years+12.2 old (median 71 years old, range 11–98 years). Over the 10 year period, there were more females (54.2% females vs 45.8% males). Sick sinus syndrome remains the most common indication for pacemaker implantation (60.7%) and the second most common indication was AV block (35.3%). This trend was consistently seen over the decade. The number of females was higher in the sick sinus syndrome group (59.8% females vs 40.2% males) whereas the proportion of males was higher in the complete heart block group (46.5% females vs 53.5% males). In conclusion, there is an increase in the number of pacemakers implanted likely due to an aging population. Females remain consistently higher and sick sinus syndrome remains the most important indication for pacing. With the rapidly aging population, it would be expected that this trend would continue to increase over the next decade.
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- 2011
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28. Remote Magnetic Navigation for Mapping and Ablation of Outflow Tract Ventricular Arrhythmia
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Daniel Chong, Chi Keong Ching, Reginald Liew, Wee Siong Teo, and Amit Kumar Malik
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medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,Remote magnetic navigation ,medicine.medical_treatment ,Stereotaxis ,Catheter ablation ,Ablation ,Vt ablation ,Surgery ,Catheter ,cardiovascular system ,medicine ,Fluoroscopy ,Outflow ,Cardiology and Cardiovascular Medicine ,Nuclear medicine ,business - Abstract
Catheter ablation provides curative treatment of outflow tract VT or frequent symptomatic ventricular arrhythmias. The remote magnetic navigation system (Stereotaxis) involves moving a catheter with a magnetic tip inside a 0.08–0.1 Tesla magnetic field and mapping done with the CARTO and ablation with a coolflow catheter. We report our experience with the Stereotaxis from July 2009 to May 2011 for ablation of outflow tract VA. There were 42 pts (19 males: 23 females) with a mean age of 45.0+13.8 years. The arrhythmias were RVOT VT in 37, aortic cusp VT 4 and aorto-mitral in 1. 72% of the patients had the procedure done with a single catheter only. The mean procedure time was 160.7+69.6 mins (range 63–330 mins) and mean fluoroscopy time 15.4+22.0 mins (range 1.0–120 mins). When compared to a previous group of 44 outflow tract VT ablation using manual technique, the mean procedure time was 153.9+55.4 mins (80–285 mins) and mean fluoroscopy time was 39.3+25.8 mins (10.9–117.6 mins). Acutely 92.8% of the cases were successfully ablated. There were no major complications. In conclusion, remote magnetic navigation with the Stereotaxis allows precise mapping and successful ablation in the majority of pts with outflow tract ventricular arrhythmias. The procedure time is not reduced significantly but there is a reduction in fluoroscopy time.
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- 2011
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29. Electrophysiological Characteristics of Patients Who Undergo Two Or More Ablations for Atrial Fibrillation
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Daniel Chong, Boon Yew Tan, Jiang Ming Fam, Reginald Liew, Wee Siong Teo, and Chi Keong Ching
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medicine.medical_specialty ,business.industry ,medicine.medical_treatment ,Anterior wall ,Atrial fibrillation ,Catheter ablation ,Cardioversion ,medicine.disease ,Ablation ,Electrophysiology ,Refractory ,Internal medicine ,Anesthesia ,medicine ,Cardiology ,In patient ,Cardiology and Cardiovascular Medicine ,business - Abstract
Background: Catheter ablation of atrial fibrillation (AF) remains a challenging procedure. We aim to describe the EP characteristics of patients who underwent 2 or more ablations for AF. Methods: 17.7% of 243 patients (n=43) underwent repeat ablation for drug refractory AF. All patients underwent instrumentation of the left atrium (LA) after LA clots were excluded. Mapping of the pulmonary veins (PVs) and ablation to achieve PV isolation was performed. Additional triggers after induction were ablated. Results: The types of AF were paroxysmal AF (PAF) (n=25) or non-paroxysmal AF (NPAF) (n=18). Recovered PV potentials were seen in 97.7%: LSPV: 93%, RSPV 86%, RIPV 84% and LIPV 76%. 76.7% (n=33) of patients required additional ablation. NPAF patients required more ablation than PAF: CFAE (77.8% vs 8%, p
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- 2011
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30. Use of Support Catheter for LV Lead Placement in Challenging Biventricular Implant
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Boon Yew Tan, Daniel Chong, Reginald Liew, Chi Keong Ching, Wee Siong Teo, Chee Yang Chin, Amit Kumar Malik, and Chin Yong Ang
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medicine.medical_specialty ,Catheter ,business.industry ,Internal medicine ,medicine ,Cardiology ,Implant ,Cardiology and Cardiovascular Medicine ,business ,Coronary sinus ,Surgery - Published
- 2011
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31. EndoEpicardial Ablation of Recurrent Ventricular Tachycardia Using Remote Magnetic Navigation System (Stereotaxis)
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Reginald Liew, Chi Keong Ching, Boon Yew Tan, Wee Siong Teo, Amit Kumar Malik, and Daniel Chong
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medicine.medical_specialty ,Percutaneous ,Ejection fraction ,business.industry ,Remote magnetic navigation ,medicine.medical_treatment ,Mitral valve replacement ,Cardiomyopathy ,Stereotaxis ,Ablation ,medicine.disease ,Pericardial window ,Internal medicine ,Cardiology ,Medicine ,Cardiology and Cardiovascular Medicine ,business - Abstract
Introduction: We report two cases of recurrent VT, successfully controlled by EndoEpicardial ablation using Stereotaxis System. Case 1: 65 year female had ICD, PTCA and Mitral valve replacement, presented with recurrent monomorphic VT (CL 430 ms, LBBB superior axis), LVEF 20%. Mapping done with CARTO and Stereotaxis. RF ablation at earliest endocardial activation and low voltage areas unable to terminate VT. Epicardial approach was attempted via pericardial window. Earliest activation and presystolic potentials noted in mid posterior septal LV, RF ablation at this site terminated the VT. Subsequently slower VT 2 (CL 520 ms) was induced with earliest activation more laterally. RF ablations in mid posterior LV from lateral LV to near the septum terminated VT. Case 2: 43 year male case of dialated cardiomyopathy, LV dysfunction (EF 25%) previously failed endocardial RF ablation for VT. Percutaneous subxiphiod epicardial access was obtained. VT1 (CL 610 ms, right inferior axis, RBBB pattern) was spontaneously induced during epicardial instrumentation. Scar and area of double potentials mapped epicardially at basal anterolateral LV. Ablation at this site terminated VT. PES subsequently induced VT2 (CL 340 ms) and VT3 (CL 210 ms). Both VT mapped and ablated endocardially. Conclusion: Enhanced maneuverability of catheter by using Stereotaxis permits accurate mapping of difficult reach areas, with minimal trauma to cardiac tissue and radiation exposure.
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- 2011
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32. In Secondary Prevention ICD Patients, Does the Initial Presenting VT Cycle Length Predict Subsequent Cycle Length of VT Episodes?
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Daniel Chong, Amit Kumar Malik, Chi Keong Ching, Boon Yew Tan, Reginald Liew, and Wee Siong Teo
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Secondary prevention ,Tachycardia ,medicine.medical_specialty ,education.field_of_study ,business.industry ,medicine.medical_treatment ,Population ,Implantable cardioverter-defibrillator ,Ventricular tachycardia ,medicine.disease ,Surgery ,Internal medicine ,medicine ,Cardiology ,Sustained VT ,Implant ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,education ,business ,Cycle length - Abstract
Background: In secondary prevention patients, ICD detection zones are often tailored individually. We aim to determine whether patients initial presenting VT tachycardia cycle length (TCL) prior to ICD implant predicts subsequent VT TCL.Methods: All secondary prevention ICD patients on follow up with available records of appropriate ICD therapy for VT within a 3-year period were studied.Results: 249 VT events in 20 patients were analysed. Mean age 55.8 years, median 5-years follow up. All had sustained VT on 12-lead ECG prior to ICD implant. Mean presenting VT TCL was 313±46 (SD) ms. In majority, post implant VT TCL increased by 20–50 ms compared to at presentation (R=0.52, p=0.02). In the entire group, mean TCL of VTs post implant was 350±43 (SD) ms. Reasons for the increased TCL include medications, ischaemia, scar size changes and different VT circuits.Conclusion: In our population, VT cycle lengths post implant are on average longer, but remain correlated to presenting TCL. Detection cycle lengths 50 ms longer than the TCL of the presenting VT should be programmed if under-detection of subsequent VTs is to be minimised.
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- 2011
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33. Efficacy of Ventricular Capture Management in Patients with Single or Dual Chamber Pacemakers
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Chi Keong Ching, Daniel Chong, Amit Kumar Malik, Shufen Liang, Reginald Liew, Wee Siong Teo, Boon Yew Tan, and Hui Min Chong
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Demographics ,business.industry ,Single Chamber Pacemaker ,Medicine ,Mean age ,In patient ,Cardiology and Cardiovascular Medicine ,business ,Nuclear medicine - Abstract
Introduction: Medtronic Ventricular Capture Management (VCM) allows effective long-term management of the pacing output and thus, maximises battery longevity. The aim of this study is to determine the accuracy of the VCM and results were comparable with in-office manual threshold results (MTR). Method: Patients with bradyarrhythmia indications who received a Medtronic device with VCM were recruited. Clinical demographics were collected and analysed. The VCM data was analysed and compared with in-office MTR. VCM was turned on only 3 months after implantation. Results: There were 30 patients (13 male, 17 female) of mean age 71 years old. 13% received single chamber pacemaker. The mean duration of initial implantation was 2.5 years. 14 patients (46.7%) had identical VCM threshold results and in-office MTR. 15 patients (50%) had+0.25 V difference between VCM threshold results and in-office MTR. Only 1 patient (3.3%) was shown to have 0.5 V difference between VCM threshold results (1.125 V @ 0.4 ms) and in-office MTR (0.625 V @ 0.4 ms). Conclusion: VCM is considered to be accurate and comparable to in-office manual threshold tests at least 3 months after device implantation. VCM reliability will allow proper management of the pacing output by adjusting accordingly to the threshold obtained automatically.
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- 2011
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34. P-306 In an Asian Population of Patients with Inferior STEMI, Is the Current ECG Diagnostic Criteria of Atrial Infarction Still Applicable?
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Julian K.B. Tan, Chee Tang Chin, Soo Teik Lim, and Daniel Chong
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Community and Home Care ,medicine.medical_specialty ,medicine.diagnostic_test ,Epidemiology ,business.industry ,medicine.medical_treatment ,Stress testing ,Wellens' syndrome ,Infarction ,Physical examination ,Chest pain ,medicine.disease ,Stenosis ,T wave ,Internal medicine ,medicine ,Cardiology ,Radiology ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,business ,Cardiac catheterization - Abstract
42-year-old female presented with pressure like mid chest pain radiating to the left arm with some difficulty in breathing but described no aggravating or relieving factor. She had no prior personal or family history of cardiovascular disease. She was hemodynamically stable and had normal physical examination relevant to cardiac and pulmonary systems. EKG showed biphasic T-waves in lead V2, V3 on presentation which later progressed to deep and symmetrical T wave inversions in precordial leads. Troponins were mildly elevated. Stress testing was positive. She had a cardiac catheterization revealing 99% stenosis in proximal LAD accompanied with 70% ostial stenosis in D1. Successful PTCA with stent placement in LAD and D1 branch was conducted. Her medication regimen was optimized and she was discharged home in stable condition. Critical high grade occlusion of the proximal LAD (Wellens Syndrome) was first described in 1982 by Dr. Hein J. Wellens. Diagnostic criteria include a recent history of chest pain, normal to slightly elevated serum markers, lack of pathological Q waves or ST-segment elevation. T waves are symmetrically and deeply inverted in the precordial leads or are biphasic in V2 and V3 leads (Wellen’s sign). Appropriate assessment with rapid intervention is paramount in managing these patients as unidentified cases can progress to extensive anterior wall MI and have a worse outcome. It is absolute essential not to rely on computer generated readings in such cases as this can lead to unwarranted noninvasive testing which may have untoward consequences.
- Published
- 2009
- Full Text
- View/download PDF
35. RESPIRATORY AND HEPATIC IMPAIRMENT, IN ADDITION TO RENAL DYSFUNCTION, UP TO ONE WEEK PRIOR TO ICD IMPLANTATION PREDICTS INCREASED MORTALITY
- Author
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Daniel Chong, Reginald Liew, Kah Leng Ho, Chi Keong Ching, and Wee Siong Teo
- Subjects
medicine.medical_specialty ,Pediatrics ,business.industry ,Internal medicine ,Hepatic impairment ,medicine ,Cardiology ,Respiratory system ,Cardiology and Cardiovascular Medicine ,business ,Icd implantation - Full Text
- View/download PDF
36. Recurrent shocks from implantable cardiac defibrillator implanted 6 months ago. What is the mechanism?
- Author
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Colin Yeo, Thuan Tee Daniel Chong, Vern Hsen Tan, and Kelvin Wong
- Subjects
ICD ,inappropriate shocks ,SVT ,VT ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Published
- 2019
- Full Text
- View/download PDF
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