1
|
Kangasjarvi E, Forsey J, Simpson JS, Ng SL. "We're back in control of the story and we're not letting anyone take that away from us": patient teacher programs as means for patient emancipation. Adv Health Sci Educ Theory Pract 2024; 29:487-505. [PMID: 37455294 DOI: 10.1007/s10459-023-10255-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 06/04/2023] [Indexed: 07/18/2023]
Abstract
While patient engagement in healthcare professions education (HPE) has significantly increased in the past decades, a theoretical gap remains. What are the varied reasons as to why patients get involved with HPE programs? With a focus on understanding what drives patient involvement with HPE programs, this study examined how a patient as teacher (PAT) program was experienced by medical students, patient teachers, and faculty within a medical school. Through a phenomenographic approach, this study captures and describes the different ways our study participants experienced a PAT program (the 'phenomenon'). 24 semi-structured interviews were conducted in total, comprised of interviews with patient teachers (N = 10), medical students (N = 10) and program facilitators (N = 4) who participated in a PAT program. Our focus was on participants' description of the program and was grounded in their experiences of as well as their beliefs about it. Our findings captured 4 layers representing the qualitatively different (yet interrelated) ways in which participants experienced/perceived and conceptualized the various aspects of their experience with the PAT program: (1) A productive disruption of the learning space (2) A re-humanization within healthcare (3) A means of empowerment and agency (4) A catalyst for change and emancipation. Our outcome space results can be visually illustrated by a nesting "Matryoshka" doll, representing the four layers and depicting the process of uncovering the less conscious layers of sense-making within this phenomenon. HPE programs that are co-produced with patients and actively involve patients as teachers have the potential, but not guarantee, to be emancipatory. To engage in PAT programs that exhibit an emancipatory potential, we need to consider transformative paradigms of education, which are aligned with social change, and disrupt the traditional teacher-learner hierarchy.
Collapse
Affiliation(s)
- E Kangasjarvi
- Li Ka Shing Knowledge Institute, Applied Education Research Operatives (AERO), Faculty of Medicine, University of Toronto at St. Michael's Hospital, Unity Health Toronto, 30 Bond Street, Toronto, ON, M5B1W8, Canada.
| | - J Forsey
- University of Toronto, Rehabilitation Sciences Institute, Toronto, ON, Canada
| | - J S Simpson
- Division of General Surgery, St. Michael's Hospital, Unity Health Toronto, Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - S L Ng
- University of Toronto, Centre for Interprofessional Education, University Health Network Toronto, Toronto, ON, Canada
| |
Collapse
|
2
|
Ng SL, Azhar NA, Budin SB, Ibrahim N, Abdul Ghani NA, Abd Ghafar N, Law JX. Effects of Platelet Lysate Gels Derived from Different Blood Sources on Oral Mucosal Wound Healing: An In Vitro Study. Gels 2023; 9:gels9040343. [PMID: 37102955 PMCID: PMC10137921 DOI: 10.3390/gels9040343] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/10/2023] [Accepted: 04/11/2023] [Indexed: 04/28/2023] Open
Abstract
The rapid healing of oral ulcers is important to prevent secondary infection, especially for chronic oral ulcers. Platelet lysate (PL) is rich in growth factors for cell growth and promotes tissue regeneration. Hence, this study was performed to compare the effects of PL originating from umbilical cord blood (CB) and peripheral blood (PB) on oral mucosal wound healing. The PLs were molded into gel form in the culture insert with the addition of calcium chloride and conditioned medium for sustained release of growth factors. The CB-PL and PB-PL gels were found to degrade slowly in culture and their degradation percentages by weight were 5.28 ± 0.72% and 9.55 ± 1.82% respectively. The results from the scratch assay and Alamar blue assay showed that the CB-PL and PB-PL gels increased the proliferation (148 ± 3% and 149 ± 3%) and wound closure (94.17 ± 1.77% and 92.75 ± 1.80%) of oral mucosal fibroblasts compared to the control with no statistical differences between the two gels, respectively. Quantitative RT-PCR showed that mRNA expressions of collagen-I, collagen-III, fibronectin, and elastin genes in cells treated with CB-PL (11-, 7-, 2-, and 7-fold) and PB-PL (17-, 14-, 3-, and 7-fold) decreased compared with the control, respectively. The concentration of platelet-derived growth factor of PB-PL gel (1303.10 ± 343.96 pg/mL) showed a higher trend than CB-PL gel did (905.48 ± 69.65 pg/mL) from ELISA measurement. In summary, CB-PL gel is as effective as PB-PL gel in supporting oral mucosal wound healing, making it a potential new source of PL for regenerative treatment.
Collapse
Affiliation(s)
- Sook-Luan Ng
- Department of Craniofacial Diagnostics and Biosciences, Faculty of Dentistry, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia
| | - Nur Ain Azhar
- Centre for Diagnostic, Therapeutic and Investigative Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia
| | - Siti Balkis Budin
- Centre for Diagnostic, Therapeutic and Investigative Studies, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia
| | - Norliwati Ibrahim
- Department of Craniofacial Diagnostics and Biosciences, Faculty of Dentistry, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia
| | - Nur Azurah Abdul Ghani
- Department of Obstetrics and Gynaecology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, Bandar Tun Razak, Cheras, Kuala Lumpur 56000, Malaysia
| | - Norzana Abd Ghafar
- Department of Anatomy, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, Bandar Tun Razak, Cheras, Kuala Lumpur 56000, Malaysia
| | - Jia-Xian Law
- Centre for Tissue Engineering and Regenerative Medicine, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, Bandar Tun Razak, Cheras, Kuala Lumpur 56000, Malaysia
| |
Collapse
|
3
|
Azmi AF, Yahya MAAM, Azhar NA, Ibrahim N, Ghafar NA, Ghani NAA, Nizar MAM, Yunus SSM, Singh TKL, Law JX, Ng SL. In Vitro Cell Proliferation and Migration Properties of Oral Mucosal Fibroblasts: A Comparative Study on the Effects of Cord Blood- and Peripheral Blood-Platelet Lysate. Int J Mol Sci 2023; 24:ijms24065775. [PMID: 36982842 PMCID: PMC10058190 DOI: 10.3390/ijms24065775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 03/07/2023] [Accepted: 03/13/2023] [Indexed: 03/30/2023] Open
Abstract
Cord blood-platelet lysate (CB-PL), containing growth factors such as a platelet-derived growth factor, has a similar efficacy to peripheral blood-platelet lysate (PB-PL) in initiating cell growth and differentiation, which makes it a unique alternative to be implemented into oral ulceration healing. This research study aimed to compare the effectiveness of CB-PL and PB-PL in promoting oral wound closure in vitro. Alamar blue assay was used to determine the optimal concentration of CB-PL and PB-PL in enhancing the proliferation of human oral mucosal fibroblasts (HOMF). The percentage of wound closure was measured using the wound-healing assay for CB-PL and PB-PL at the optimal concentration of 1.25% and 0.3125%, respectively. The gene expressions of cell phenotypic makers (Col. I, Col. III, elastin and fibronectin) were determined via qRT-PCR. The concentrations of PDGF-BB were quantified using ELISA. We found that CB-PL was as effective as PB-PL in promoting wound-healing and both PL were more effective compared to the control (CTRL) group in accelerating the cell migration in the wound-healing assay. The gene expressions of Col. III and fibronectin were significantly higher in PB-PL compared to CB-PL. The PDGF-BB concentration of PB-PL was the highest and it decreased after the wound closed on day 3. Therefore, we concluded that PL from both sources can be a beneficial treatment for wound-healing, but PB-PL showed the most promising wound-healing properties in this study.
Collapse
Affiliation(s)
- Arief Faisal Azmi
- Department of Craniofacial Diagnostics and Biosciences, Faculty of Dentistry, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia
| | - Mohammad Amirul Asyraff Mohd Yahya
- Department of Craniofacial Diagnostics and Biosciences, Faculty of Dentistry, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia
| | - Nur Ain Azhar
- Department of Craniofacial Diagnostics and Biosciences, Faculty of Dentistry, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia
| | - Norliwati Ibrahim
- Department of Craniofacial Diagnostics and Biosciences, Faculty of Dentistry, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia
| | - Norzana Abd Ghafar
- Department of Anatomy, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, Bandar Tun Razak, Cheras, Kuala Lumpur 56000, Malaysia
| | - Nur Azurah Abdul Ghani
- Department of Obstetrics and Gynaecology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, Bandar Tun Razak, Cheras, Kuala Lumpur 56000, Malaysia
| | - Muhammad Aiman Mohd Nizar
- Department of Craniofacial Diagnostics and Biosciences, Faculty of Dentistry, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia
| | - Siti Salmiah Mohd Yunus
- Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia
| | - Tashveender Kaur Lakhbir Singh
- Department of Craniofacial Diagnostics and Biosciences, Faculty of Dentistry, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia
| | - Jia-Xian Law
- Centre for Tissue Engineering and Regenerative Medicine, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, Bandar Tun Razak, Cheras, Kuala Lumpur 56000, Malaysia
| | - Sook-Luan Ng
- Department of Craniofacial Diagnostics and Biosciences, Faculty of Dentistry, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur 50300, Malaysia
| |
Collapse
|
4
|
Ng SL. An assessment of multi-family dwelling recycling in Hong Kong: A managerial perspective. Waste Manag 2019; 89:294-302. [PMID: 31079743 DOI: 10.1016/j.wasman.2019.04.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 04/03/2019] [Accepted: 04/05/2019] [Indexed: 06/09/2023]
Abstract
Solid waste is an acute environmental problem in most big cities around the world. Like other highly compact cities, Hong Kong developed a recycling program that primarily targets multi-family dwellings (MFDs). This paper intends to examine the relations between three managerial factors-housing type, recycling mode, and initiative of the property manager-and MFD recycling using data collected from a territory-wide telephone survey (n = 1,016) conducted in 2017. The results indicated that housing type and initiative of the property manager had significant relations with the recycling behavior of residents. The findings may supplement previous recycling studies and provide a reference for the improved implementation of the MFD recycling program in Hong Kong.
Collapse
Affiliation(s)
- S L Ng
- Centre for Environmental Policy and Resource Management, Department of Geography and Resource Management, the Chinese University of Hong Kong, Hong Kong
| |
Collapse
|
5
|
Ng SL, Nordin A, Abd Ghafar N, Suboh Y, Ab Rahim N, Chua KH. Acanthamoeba-mediated cytopathic effect correlates with MBP and AhLBP mRNA expression. Parasit Vectors 2017; 10:625. [PMID: 29282148 PMCID: PMC5745754 DOI: 10.1186/s13071-017-2547-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 11/21/2017] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND In recent years, the concern of Acanthamoeba keratitis has increased since the infection is often associated with contact lens use. Partial 18S rRNA genotypic identification of Acanthamoeba isolates is important to correlate with pathophysiological properties in order to evaluate the degree of virulence. This is the first report of genotypic identification for clinical isolates of Acanthamoeba from corneal scrapings of keratitis in Malaysia. This study is also the first to correlate the mRNA expression of MBP and AhLBP as virulent markers for axenic strains of Acanthamoeba. RESULTS In this study, ten clinical isolates were obtained from corneal scrapings. Rns genotype and intra-genotypic variation at the DF3 region of the isolates were identified. Results revealed that all clinical isolates belonged to the T4 genotype, with T4/6 (4 isolates), T4/2 (3 isolates), T4/16 (2 isolates) and one new genotype T4 sequence (T4/36), being determined. The axenic clinical isolates were cytopathogenic to rabbit corneal fibroblasts. MBP and AhLBP mRNA expression are directly correlated to Acanthamoeba cytopathic effect. CONCLUSIONS All ten Malaysian clinical isolates were identified as genotype T4 which is predominantly associated with AK. Measuring the mRNA expression of Acanthamoeba virulent markers could be useful in the understanding of the pathogenesis of Acanthamoeba keratitis.
Collapse
Affiliation(s)
- Sook-Luan Ng
- Department of Physiology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, 56000, Kuala Lumpur, Bandar Tun Razak, Malaysia
| | - Anisah Nordin
- Department of Parasitology and Medical Entomology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, 56000, Kuala Lumpur, Bandar Tun Razak, Malaysia
| | - Norzana Abd Ghafar
- Department of Anatomy, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, 56000, Kuala Lumpur, Bandar Tun Razak, Malaysia
| | - Yusof Suboh
- Department of Parasitology and Medical Entomology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, 56000, Kuala Lumpur, Bandar Tun Razak, Malaysia
| | - Noraina Ab Rahim
- Department of Parasitology and Medical Entomology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, 56000, Kuala Lumpur, Bandar Tun Razak, Malaysia
| | - Kien-Hui Chua
- Department of Physiology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latif, 56000, Kuala Lumpur, Bandar Tun Razak, Malaysia.
| |
Collapse
|
6
|
Jamil K, Chua KH, Joudi S, Ng SL, Yahaya NH. Development of a cartilage composite utilizing porous tantalum, fibrin, and rabbit chondrocytes for treatment of cartilage defect. J Orthop Surg Res 2015; 10:27. [PMID: 25889942 PMCID: PMC4327955 DOI: 10.1186/s13018-015-0166-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 01/14/2015] [Indexed: 12/01/2022] Open
Abstract
Objective Functional tissue engineering has emerged as a potential means for treatment of cartilage defect. Development of a stable cartilage composite is considered to be a good option. The aim of the study was to observe whether the incorporation of cultured chondrocytes on porous tantalum utilizing fibrin as a cell carrier would promote cartilage tissue formation. Methods Rabbit articular chondrocytes were cultured and seeded onto tantalum with fibrin as temporary matrix in a composite, which was divided into three groups. The first group was kept in vitro while a total of 12 constructs were implanted into the dorsum of mice for the second and third groups. The implanted tissues were harvested after 4 weeks (second group) and after 8 weeks (third group). Specific characteristic of cartilage growth were studied by histological and biochemical assessment, immunohistochemistry, and quantitative PCR analysis. Results Histological and biochemical evaluation of the formed cartilage using hematoxylin and eosin and Alcian blue staining showed lacunae chondrocytes embedded in the proteoglycan rich matrix. Dimethylmethylene blue assay demonstrated high glycosaminoglycans content in the removed tissue following 8 weeks of implantation. Immunohistochemistry results showed the composites after implantation expressed high collagen type II. Quantitative PCR results confirmed a significant increase in cartilage associated genes expression (collagen type II, AggC, Sox 9) after implantation. Conclusion Tantalum scaffold with fibrin as cell carrier promotes chondrocyte proliferation and cartilaginous tissue formation. Producing hyaline cartilage within a stable construct of tantalum and fibrin has a potential for treatment of cartilage defect.
Collapse
Affiliation(s)
- Kamal Jamil
- Department of Orthopaedic and Traumatology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latiff, Bandar Tun Razak, 56000, Cheras, Kuala Lumpur, Malaysia.
| | - Kien-Hui Chua
- Department of Physiology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300, Kuala Lumpur, Malaysia.
| | - Samad Joudi
- Department of Orthopaedic and Traumatology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latiff, Bandar Tun Razak, 56000, Cheras, Kuala Lumpur, Malaysia.
| | - Sook-Luan Ng
- Department of Physiology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300, Kuala Lumpur, Malaysia.
| | - Nor Hamdan Yahaya
- Department of Orthopaedic and Traumatology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Jalan Yaacob Latiff, Bandar Tun Razak, 56000, Cheras, Kuala Lumpur, Malaysia.
| |
Collapse
|
7
|
Khor SM, Ng SL, Lim PE, Seng CE. The effects of nickel(II) and chromium(VI) on oxygen demand, nitrogen and metal removal in a sequencing batch reactor. Environ Technol 2011; 33:1903-1914. [PMID: 22439579 DOI: 10.1080/09593330.2011.568008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The objective of this study was to evaluate the effects ofNi(II) and Cr(VI) individually and in combination on the simultaneous removal of chemical oxygen demand (COD), nitrogen and metals under a sequencing batch reactor (SBR) operation. Three identical laboratory-scale SBRs were operated with FILL, REACT, SETTLE, DRAW and IDLE periods in a ratio of 1:12:1:2:8 for a cycle time of 24 h until the steady state was achieved. Nickel(II) at increasing concentrations up to 35 mg/L was added to one of the reactors; Cr(VI) at increasing concentrations up to 25 mg/L was added to a second reactor; while a combination of Ni(II) and Cr(VI) in equal concentrations up to 10 mg/L was added to a third reactor. The results demonstrate that both Ni(II) and Cr(VI) exerted a more pronounced inhibitory effect on the removal of ammonia nitrogen (AN) than on COD removal. Synergistic and antagonistic inhibitory effects on the rates of COD and AN removal, respectively, were observed for the 50% Ni(II) and 50% Cr(VI) (w/w) mixture in the concentration range between 10 and 20 mg/L. The simultaneous presence of 50% Ni(II) and 50% Cr(VI) at a concentration of 20 mg/L resulted in system failure.
Collapse
Affiliation(s)
- S M Khor
- School of Chemical Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | | | | | | |
Collapse
|
8
|
Haiwang L, Nguyen NT, Wong TN, Ng SL. Microfluidic on-chip fluorescence-activated interface control system. Biomicrofluidics 2010; 4:44109. [PMID: 21173886 PMCID: PMC3003716 DOI: 10.1063/1.3516036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2010] [Accepted: 10/18/2010] [Indexed: 05/25/2023]
Abstract
A microfluidic dynamic fluorescence-activated interface control system was developed for lab-on-a-chip applications. The system consists of a straight rectangular microchannel, a fluorescence excitation source, a detection sensor, a signal conversion circuit, and a high-voltage feedback system. Aqueous NaCl as conducting fluid and aqueous glycerol as nonconducting fluid were introduced to flow side by side into the straight rectangular microchannel. Fluorescent dye was added to the aqueous NaCl to work as a signal representing the interface position. Automatic control of the liquid interface was achieved by controlling the electroosmotic effect that exists only in the conducting fluid using a high-voltage feedback system. A LABVIEW program was developed to control the output of high-voltage power supply according the actual interface position, and then the interface position is modified as the output of high-voltage power supply. At last, the interface can be moved to the desired position automatically using this feedback system. The results show that the system presented in this paper can control an arbitrary interface location in real time. The effects of viscosity ratio, flow rates, and polarity of electric field were discussed. This technique can be extended to switch the sample flow and droplets automatically.
Collapse
|
9
|
Ng SL, Seng CE, Lim PE. Bioregeneration of activated carbon and activated rice husk loaded with phenolic compounds: Kinetic modeling. Chemosphere 2010; 78:510-516. [PMID: 20035966 DOI: 10.1016/j.chemosphere.2009.11.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Revised: 11/26/2009] [Accepted: 11/26/2009] [Indexed: 05/28/2023]
Abstract
A kinetic model consisting of first-order desorption and biodegradation processes was developed to describe the bioregeneration of phenol- and p-nitrophenol-loaded powdered activated carbon (PAC) and pyrolyzed rice husk (PRH), respectively. Different dosages of PAC and PRH were loaded with phenol or p-nitrophenol by contacting with the respective phenolic compound at various concentrations. The kinetic model was used to fit the phenol or p-nitrophenol concentration data in the bulk solution during the bioregeneration process to determine the rate constants of desorption, k(d), and biodegradation, k. The results showed that the kinetic model fitted relatively well (R(2)>0.9) to the experimental data for the phenol- and p-nitrophenol-loaded PAC as well as p-nitrophenol-loaded PRH. Comparison of the values of k(d) and k shows that k is much greater than k(d). This indicates clearly that the desorption process is the rate-determining step in bioregeneration and k(d) can be used to characterize the rate of bioregeneration. The trend of the variation of the k(d) values with the dosages of PAC or PRH used suggests that higher rate of bioregeneration can be achieved under non-excess adsorbent dosage condition.
Collapse
Affiliation(s)
- S L Ng
- Universiti Sains Malaysia, Penang, Malaysia
| | | | | |
Collapse
|
10
|
Ng SL, Seng CE, Lim PE. Quantification of bioregeneration of activated carbon and activated rice husk loaded with phenolic compounds. Chemosphere 2009; 75:1392-400. [PMID: 19307013 DOI: 10.1016/j.chemosphere.2009.02.049] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 02/20/2009] [Accepted: 02/20/2009] [Indexed: 05/23/2023]
Abstract
The bioregeneration efficiencies of powdered activated carbon (PAC) and pyrolyzed rice husk loaded with phenol and p-nitrophenol were quantified by oxygen uptake measurements using the respirometry technique in two approaches: (i) simultaneous adsorption and biodegradation and (ii) sequential adsorption and biodegradation. It was found that the applicability of the simultaneous adsorption and biodegradation approach was constrained by the requirement of adsorption preceding biodegradation in order to determine the initial adsorbent loading accurately. The sequential adsorption and biodegradation approach provides a good estimate of the upper limit of the bioregeneration efficiency for the loaded adsorbent in the simultaneous adsorption and biodegradation processes. The results showed that the mean bioregeneration efficiencies for PAC loaded with phenol and p-nitrophenol, respectively, obtained using the two approaches were in good agreement.
Collapse
Affiliation(s)
- S L Ng
- School of Chemical Sciences, Universiti Sains Malaysia, 11800 Penang, Malaysia
| | | | | |
Collapse
|
11
|
Ng SL, Lam KC. Respiratory suspended particulate (RSP) concentration and its implications to roadside workers: a case study of Hong Kong. Environ Monit Assess 2001; 72:235-247. [PMID: 11720226 DOI: 10.1023/a:1012097121404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Respiratory Suspended Particulates (RSPs) have attracted increasing interest in recent years because of the potential risk of RSPs to human health. In Hong Kong, a large population of roadside workers is believed to be continuously exposed to high levels of RSPs. In this study, the roadside RSP concentrations at 72 locations in 6 urban districts of different land use types in Hong Kong are examined. Results show that the RSP pollution in Hong Kong's roadside environment is quite serious. The average RSP concentration at 61.11% of sampling sites is over 180 microg m(-3), the highest 24 h RSP mean concentration recommended by the Environmental Protection Department of Hong Kong. Analyses of RSP concentration data with reference to the local environmental conditions indicate that, among various environmental factors, land use, population density and traffic flow are important determinants of the RSP level. Because many roadside workers are exposed to high levels of RSP for prolonged periods, it is necessary to increase the public awareness of the health hazard of roadside workers.
Collapse
Affiliation(s)
- S L Ng
- Geography Department, The Chinese University of Hong Kong, Shatin, NT
| | | |
Collapse
|
12
|
Chan LS, Ng SL, Davis AM, Yim WW, Yeung CH. Magnetic properties and heavy-metal contents of contaminated seabed sediments of Penny's Bay, Hong Kong. Mar Pollut Bull 2001; 42:569-583. [PMID: 11488237 DOI: 10.1016/s0025-326x(00)00203-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Magnetic properties and heavy-metal concentrations of vibrocore samples were found to be potential indicators of shipping contamination in seabed sediments in Hong Kong Harbour. Geochemical results of 74 vibrocores located off Penny's Bay on Lantau Island revealed an enrichment of heavy metals in the upper 1-2 m of the cores within the eastern part of the study site. Whole-core magnetic susceptibility measurements also showed a greater concentration of magnetic particles in the surficial layer of these cores. A significant correlation exists between the magnetic susceptibility and the concentrations of Pb, Zn and Cu, as well as the Tomlinson pollution load index (PLI). The proximity of these cores to a major navigation fairway and an anchorage site suggests probable contamination of the surficial seabed sediments by shipping-related wastes. A study of the magnetic properties of one of the cores, VT60, revealed a difference in the magnetic properties between the contaminated and the uncontaminated sediments. Samples from the contaminated zone exhibited relatively stronger magnetic remanence and susceptibility. The two groups of samples also formed distinct trends on the hysteresis ratios plot. A level of unusually high magnetic susceptibility within the contaminated zone was attributable to the presence of strongly magnetized granules, which were probably refuse from shipping-related activities. Geochemical and magnetic results were also conducted on samples of different size-fractions from this core. The < 63 microns fraction was found to contain a relatively higher magnetic susceptibility and greater heavy-metal content.
Collapse
Affiliation(s)
- L S Chan
- Department of Earth Sciences, University of Hong Kong, Pokfulham Road, Hong Kong.
| | | | | | | | | |
Collapse
|
13
|
Zhang HX, Kam CH, Zhou Y, Ng SL, Lam YL, Buddhudu S. Green up-conversion emission in Er3+:BaTiO3 sol-gel powders. Spectrochim Acta A Mol Biomol Spectrosc 2000; 56A:2231-2234. [PMID: 11058068 DOI: 10.1016/s1386-1425(00)00276-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Bright green emissions at 549 and 526 nm have been observed from sol-gel derived Er3+:BaTiO3 powders upon excitations at two near infrared (NIR) wavelengths of 973 and 816 nm. The decay characteristics were measured and studied. It was found that the predominant emission at 549 nm has very different lifetimes upon excitation at 973 and 816 nm, which was explained by the mechanisms of excited state absorption (ESA) of individual Er3+ ion and cooperative energy transfer (CET) between two near Er3+ ions for the up-conversion emission. Analysis also showed that 973-nm excitation is more effective for the green up-conversion emission.
Collapse
Affiliation(s)
- H X Zhang
- Photonics Research Group, School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore
| | | | | | | | | | | |
Collapse
|
14
|
Yung A, Wong V, Yeung R, Yeun SM, Ng SL, Tse SF, Wong E, Chan A. Outcome measure for paediatric rehabilitation: use of the Functional Independence Measure for children (WeeFIM). A pilot study in Chinese children with neurodevelopmental disabilities. Pediatr Rehabil 1999; 3:21-8. [PMID: 10367290 DOI: 10.1080/136384999289649] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
PURPOSE To study the use of Functional Independence Measure for children (WeeFIM) in monitoring neurorehabilitation programmes for children with neurodevelopmental disabilities. METHODS The neurorehabilitation team of the Children's Habilitation Institute of the Duchess of Kent Children's Hospital were trained to administer the WeeFIM. The WeeFIM was administered to children with various neuro-developmental impairment groups undergoing neurorehabilitation programmes in the hospital inpatient and also outpatient setting. The WeeFIM was scored on hospital admission and prior to discharge for those admitted for the rehabilitation programme. The WeeFIM profile was then monitored half yearly. The pilot study used WeeFIM in assessing 104 children with different medical disease categories. The disease or impairment categories included very low birth weight babies (n = 44), cerebral palsy (n = 19), Down's syndrome (n = 9), pervasive developmental disorder (n = 11), Duchenne Muscular Dystrophy (n = 18), and others (n = 3). RESULTS WeeFim could be used to measure disability, monitor progress, enhance communication, measure the effectiveness of treatment, and document the benefits of rehabilitation intervention. It also served as a networking of neurorehabilitation programmes for different impairment categories in a continuum of settings: hospital, community, school and at home. WeeFIM was found to be a quick and reliable functional assessment instrument in this rehabilitation facility. CONCLUSIONS WeeFIM could be used to assist neurorehabilitation clinicians in the selection of short term realistic goals and long term rehabilitation strategies for children with various neurodevelopmental disabilities, and the subsequent progress of the children could be monitored objectively.
Collapse
Affiliation(s)
- A Yung
- Department of Pediatrics, University of Hong Kong, Queen Mary Hospital
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Abstract
A new fiber-optic catheter for in vivo blood-flow measurements has been developed. The catheter is designed to measure blood flow in both the forward (toward the catheter tip) and reverse (away from the catheter tip) flow directions. It consists of two multimode optical fibers with core diameter of 50 microns and cladding diameter of 125 microns. One fiber transmits the laser beam into blood and the other receives the backscattered light from the erythrocytes within the probe volume. In the flow experiment, it was found that the flow within the boundary layer is indeed laminar and, hence, the relationship between the Doppler shift frequencies and the flow velocities is linear, thereby making the linear calibration possible for predicting the free stream flow velocity. Plots of the maximum shift frequency (frequency at which the Doppler spectrum disappeared into the noise spectrum) against the flow velocities are found to be more linear in both the forward and reverse flow directions than that of the dominant shift frequency (frequency with the highest amplitude). These results were reaffirmed by the numerical flow simulation along the catheter side wall.
Collapse
Affiliation(s)
- S C Tjin
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore.
| | | | | |
Collapse
|
16
|
Muchmore SW, Sattler M, Liang H, Meadows RP, Harlan JE, Yoon HS, Nettesheim D, Chang BS, Thompson CB, Wong SL, Ng SL, Fesik SW. X-ray and NMR structure of human Bcl-xL, an inhibitor of programmed cell death. Nature 1996; 381:335-41. [PMID: 8692274 DOI: 10.1038/381335a0] [Citation(s) in RCA: 1074] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
THE Bcl-2 family of proteins regulate programmed cell death by an unknown mechanism. Here we describe the crystal and solution structures of a Bcl-2 family member, Bcl-xL (ref. 2). The structures consist of two central, primarily hydrophobic alpha-helices, which are surrounded by amphipathic helices. A 60-residue loop connecting helices alpha1 and alpha2 was found to be flexible and non-essential for anti-apoptotic activity. The three functionally important Bcl-2 homology regions (BH1, BH2 and BH3) are in close spatial proximity and form an elongated hydrophobic cleft that may represent the binding site for other Bcl-2 family members. The arrangement of the alpha-helices in Bcl-xL is reminiscent of the membrane translocation domain of bacterial toxins, in particular diphtheria toxin and the colicins. The structural similarity may provide a clue to the mechanism of action of the Bcl-2 family of proteins.
Collapse
Affiliation(s)
- S W Muchmore
- Protein Crystallography, Pharmaceutical Discovery Division, Abbott Laboratories, Abbott Park, Illinois 60064, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Ng SL, Martin JL, Romans SE. A community's attitudes towards the mentally ill. N Z Med J 1995; 108:505-8. [PMID: 8532235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
AIM To assess the general community's knowledge of mental illness and personal experience of people with mental illness. METHOD Three hundred randomly selected Dunedin residents were surveyed by a postal questionnaire. The instruments used to measure attitudes were a shortened form of the Californian attitudes towards mental illness scale (CAMI scale) and a social distance scale. In addition, questions were asked about the respondent's age, gender, marital status, level of education, their main source of opinion, their experience with the mentally ill, and their beliefs about the causes and types of mental illness. RESULTS Having known a person with mental illness facilitates more intimate relationships with people with a mental illness. Sociodemographic variables did not predict attitudes on the CAMI scale. Most respondents who had been in contact with the mentally ill held informed and enlightened views. CONCLUSION The community needs and welcomes information on the subject of mental illness and has a positive outlook for the future planning of the rehabilitation of people with mental illness.
Collapse
Affiliation(s)
- S L Ng
- Department of Psychological Medicine, University of Otago, Dunedin
| | | | | |
Collapse
|
18
|
Ngai CW, Ng SL, Cockram CS, Lee CM, Yeung VT, Nicholls MG. Interaction of natriuretic peptides and cGMP production via the same receptor in mouse astrocytes. Brain Res 1992; 589:275-8. [PMID: 1327412 DOI: 10.1016/0006-8993(92)91287-o] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Atrial and brain natriuretic peptides have been found previously to bind to specific receptors on cultured mouse astrocytes and to stimulate cyclic guanosine 5-monophosphate (cGMP) production with similar dose dependency although brain natriuretic peptide (BNP) shows a greater maximal stimulatory effect. The present study provides evidence that both peptides work through the same pathway. No additive or synergistic effect was observed when astrocytes were exposed to both peptides. However, human ANF(99-126) at high concentrations partially inhibited porcine BNP induced cGMP production to the level seen with ANF alone. ANF could be viewed as a partial agonist of pBNP competing for the same effector sites. Differences in structure between human ANF(99-126) and porcine BNP may account for the difference in cGMP response. The interaction between the two peptides and the cGMP response does not reflect receptor binding affinities and is likely to be a post-binding event.
Collapse
Affiliation(s)
- C W Ngai
- Department of Medicine, Chinese University of Hong Kong, Shatin, N.T
| | | | | | | | | | | |
Collapse
|
19
|
Abstract
This paper presents a new method for the mammographic detection and classification of two types of breast tumors, stellate lesions and circumscribed lesions. The method assumes that both types of tumors appear as approximately circular, bright masses with a fuzzy boundary and that stellate lesions are in addition surrounded by a radiating structure of sharp, fine lines. Experimental results for a set of 27 mammograms are presented and the method is shown to have a high detection rate and an extremely low false positive rate.
Collapse
Affiliation(s)
- S L Ng
- Department of Computing Science, University of Alberta, Edmonton, Canada
| | | |
Collapse
|
20
|
Ng TB, Ng SL. Beta-endorphin-like and adrenocorticotropin-like materials in heart tissues of the rat, gerbil, hamster and guinea pig. Comp Biochem Physiol C Comp Pharmacol Toxicol 1990; 95:45-53. [PMID: 1971555 DOI: 10.1016/0742-8413(90)90081-j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
1. Heart tissues of several rodent species including the rat, gerbil (Meriones unguiculatus), hamster (Mesocricetus auratus) and guinea pig (Cavia porcellus) were extracted with an acetone-water-HCl mixture. An acid acetone powder was obtained by adding a copious volume of acetone to the extract. 2. Rat heart acid acetone powder was subjected to ion exchange chromatography on CM-cellulose. Gerbil heart acid acetone powder was subjected to salt fractionation, gel filtration on Sephadex G-10 and then ion exchange chromatography on CM-cellulose. Hamster and guinea pig heart acid acetone powders were subjected to gel filtration on Sephadex G-25. 3. The fractions were assayed for the ability to stimulate corticosterone production in isolated rat adrenal decapsular (zona fasciculata, zona reticularis and medulla) cells, to displace D-ala2-D-leu5-(tyrosyl-3,5-3H) enkephalin from binding to rat brain membranes, and to inhibit 125I-human beta-endorphin from binding to its antibodies. 4. The widespread occurrence of beta-endorphin-like immunoreactivity among the rat heart CM-cellulose fractions may reflect different species of beta-endorphin. The fraction with the highest beta-endorphin-like immunoreactivity and opiate receptor binding activity was strongly adsorbed on CM-cellulose. 5. In hamster and guinea pig hearts, beta-endorphin-like immunoreactivity and opiate receptor binding activity were distributed among high molecular weight and low molecular weight fractions. 6. In gerbil hearts, opiate receptor binding activity was present in fractions unretarded on Sephadex G-10 (i.e. with a molecular weight greater than 700) as well as in the retarded fractions (i.e. with a molecular weight smaller than 700).(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- T B Ng
- Department of Biochemistry, Faculty of Medicine, Chinese University of Hong Kong
| | | |
Collapse
|
21
|
Ng SL, Ng TN. Materials with opiate receptor binding activity in bovine testis and ovine pancreas. Biochem Int 1987; 14:1087-96. [PMID: 2839185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Two groups of opiate-like materials, one with a molecular weight equal to or greater than 5000 daltons and another with a molecular weight smaller than 5000 daltons as judged by gel filtration on Sephadex G-25, were detected in bovine testes. The existence of opiate-like materials with a molecular weight smaller than 5000 daltons was demonstrated in ovine pancreas. The pancreatic fraction most strongly adsorbed on CM-cellulose possessed the highest opiate receptor binding activity. Bovine testis contained corticotropin-like material(s) which stimulated corticosterone production by isolated rat adrenal cells.
Collapse
Affiliation(s)
- S L Ng
- Department of Biochemistry, Faculty of Medicine, Chinese University of Hong Kong, Shatin
| | | |
Collapse
|
22
|
Abstract
1. Pigeon brain acetone powder was extracted with a mixture of acetone, water and hydrochloric acid (40:21:1 v/v/v). The extract was added to a large volume of chilled acetone. 2. The resultant precipitate was washed with cold acetone and then chromatographed on Sephadex G-25. The void volume peak constituted fraction A. The trailing peak immediately following fraction A was divided into two fractions designated B and C. 3. Fraction B (mol. wt less than 5,000) stimulated corticosterone production in isolated rat adrenal cells while the other fractions were devoid of similar ACTH-like bioactivity. 4. None of the fractions showed activity in the opiate radioreceptor assay or hot plate test, implying the absence or presence of only trace amounts of opiate-like materials. Other possibilities that cannot be ruled out include the presence of molecules with substitutions in the sequence by amino acids that result in little or no activity.
Collapse
Affiliation(s)
- S L Ng
- Department of Biochemistry, Faculty of Medicine, Chinese University of Hong Kong, Shatin, NT
| | | |
Collapse
|
23
|
|
24
|
Woo KT, Tan YO, Lau YK, Ng SL, Chew TS, Chan SH, Lim CH. Loss of concanavalin A induced suppressor T-lymphocyte function in patients with mesangial IgA nephritis. Ann Acad Med Singap 1982; 11:24-7. [PMID: 6462097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Using the method of concanavalin A (Con a) inducible suppressor activity the peripheral mononuclear cells (PMC) of 17 patients with Mesangial IgA nephritis, 13 patients with idiopathic mesangial proliferative glomerulonephritis but with no IgA deposits on immunofluorescence (Non-IgA nephritis) and 18 healthy subjects were studied. DNA synthesis was measured by incorporation of 3H Thymidine. The mean suppression index (S.I.) of 0.94 +/- 0.08 (SEM) in the IgA nephritic patients was significantly different from that of the non-IgA nephritic patients (0.67 +/- 0.05) (P less than 0.01) as well as the group of normal healthy controls (0.64 +/- 0.05) (P less than 0.0025). The data show that patients with IgA nephritis have abnormal suppressor cell function and suggest an autoimmune basis in the pathogenesis of IgA nephritis.
Collapse
|
25
|
Woo KT, Tan YO, Chong PY, Lau YK, Ng SL, Lim CH. Beta-thromboglobulin in renal failure. Aust N Z J Med 1980; 10:581. [PMID: 6162446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
|