Muhammad Adnan abdullah - Academia.edu (original) (raw)

Papers by Muhammad Adnan abdullah

Research paper thumbnail of Real Time Principal Component Analysis

2019 IEEE 35th International Conference on Data Engineering (ICDE)

By processing the data in motion, real-time data processing enables us to extract instantaneous r... more By processing the data in motion, real-time data processing enables us to extract instantaneous results from online input data that ensures timely responsiveness to events as well as a much enhanced capacity to process large data sets. This is especially important when decision loops include querying and processing data on the web where size and latency considerations make it impossible to process raw data in real-time. This makes dimensionality reduction techniques, like principal component analysis (PCA), an important data preprocessing tool to gain insights into data. In this paper, we propose a variant of PCA, that is suited for real-time applications. In the real-time version of the PCA problem, we maintain a window over the most recent data and project every incoming row of data into lower dimensional subspace, which we generate as the output of the model. The goal is to minimize the reconstruction error of the output from the input. We use the reconstruction error as the termination criteria to update the eigenspace as new data arrives. To verify whether our proposed model can capture the essence of the changing distribution of large datasets in real-time, we have implemented the algorithm and evaluated performance against carefully designed simulations that change distributions of data sources over time in a controllable manner. Furthermore, we have demonstrated that our algorithm can capture the changing distributions of real-life datasets by running simulations on datasets from a variety of real-time applications e.g. localization, customer expenditure, etc. We propose algorithmic enhancements that rely upon spectral analysis to improve dimensionality reduction. Results show that our method can successfully capture the changing distribution of data in a real-time scenario, thus enabling real-time PCA.

Research paper thumbnail of Implementasi Model Pembelajaran Kooperatif Tipe STAD Dalam Meningkatkan Hasil Belajar Siswa Pendidikan Dasar

AL-ASASIYYA: Journal Of Basic Education

This study aims to determine the implementation of the STAD type cooperative learning model in im... more This study aims to determine the implementation of the STAD type cooperative learning model in improving the learning outcomes of basic education students. This study uses classroom action research with 15 students as subjects of Class IV SD Negeri Sebanjar, Alor Village, Northwest Alor District, East Nusa Tenggara, consisting of 7 males and 8 females. This research was carried out in two cycles, and each cycle was carried out in 3 meetings including tests at the end of each cycle. Data collection was carried out using learning outcomes tests at the end of each cycle, observation sheets for teacher and student activities carried out during the learning process and student response questionnaires. The collected data was then analyzed using descriptive analysis techniques. The results of this classroom action research analysis found that the implementation of the STAD Type Cooperative learning model for two cycles has been able to improve the learning outcomes of Class IV students at ...

Research paper thumbnail of Within-herd phenotypic and genetic trend lines for milk yield in Holstein-Friesian dairy cows

Journal of Cell and Animal Biology, Nov 30, 2007

A total of 937 pedigree, breeding and performance records of 567 Friesian cows at the Livestock E... more A total of 937 pedigree, breeding and performance records of 567 Friesian cows at the Livestock Experiment Station Bhunikey Dist. Kasur (Pakistan) spanning the years 1982-2001 were analyzed using Best Linear Unbiased Predictions procedure. Individual animal models were fitted to total milk yield from all lactations to estimate breeding values by Restricted Maximum Likelihood methodology. Milk yield and lactation length averaged 3391.66 ± 137.97 kg and 278.40 ± 90.17 days, respectively. The estimated breeding values for milk yield ranged from-354 to 503 kg. The corresponding values for the standing herd ranged from-209 to 294 kg. The genetic trend for milk yield was slightly positive indicating that the sires used during the last 20 years were of better breeding values. Phenotypic reduction in milk yield over time was observed, a probable reflection of the inability of the cows to adapt to the local environment and other environmental inadequacies.

Research paper thumbnail of Kuala Lumpur draft city plan 2020 local inquiry: an analysis of its shortcomings

Research paper thumbnail of Preferred fence design: a case study of selected communities in the Klang valley

Research paper thumbnail of Ebola, the killer virus

Infectious Diseases of Poverty, 2015

Research paper thumbnail of Constrained model predictive control of proton exchange membrane fuel cell

Journal of Mechanical Science and Technology, 2014

A constrained model predictive control (MPC) is designed to regulate the air flow rate of proton ... more A constrained model predictive control (MPC) is designed to regulate the air flow rate of proton exchange membrane fuel cell (PEMFC). Oxygen excess ratio, compressor flow rate and supply manifold pressure are constrained to avoid oxygen starvation, surge and choke phenomena. This is achieved by manipulating compressor voltage and stack current. The choice of the manipulated input to satisfy a constraint is investigated. Surge and choke avoidance is successful, when compressor voltage is manipulated. When stack current is utilized to satisfy surge and choke constraints, a large unrealistic current is needed. Oxygen starvation is successfully avoided utilizing stack current, while compressor voltage manipulation fails to prevent oxygen starvation. Thus, a current governor is implemented to handle oxygen starvation, while the compressor voltage is constrained to avoid surge and choke. Quadratic programming optimization, Laguerre and exponential weight function are employed to reduce the computational burden of the controller. The simulation results prove that the proposed controller managed to satisfy all constraints without any conflict.

Research paper thumbnail of Effects of diseased ECG on the robustness of ECG biometric systems

2010 IEEE EMBS Conference on Biomedical Engineering and Sciences (IECBES), 2010

This paper looks into the effects of diseased subjects on the recognition rate of an ECG biometri... more This paper looks into the effects of diseased subjects on the recognition rate of an ECG biometric system. A novel technique for feature extraction, linear predictive coding, is implemented along with neural networks for the classifier. Diseased ECG has been shown reduce the recognition rate of the system by only less than 1% and thus the system is robust towards diseased ECG. This allows for the system incorporating linear predictive coding to be used in practical situations where some users may not be aware of their health state and may have diseased ECG signals.

Research paper thumbnail of Analysis of effective channel placement for an EEG-based biometric system

2010 IEEE EMBS Conference on Biomedical Engineering and Sciences (IECBES), 2010

... 1, Khazaimatol S Subari#2, Justin Leo Cheang Loong∗3 and Nurul Nadia Ahmad#4 #Faculty of Engi... more ... 1, Khazaimatol S Subari#2, Justin Leo Cheang Loong∗3 and Nurul Nadia Ahmad#4 #Faculty of Engineering, Multimedia University, Cyberjaya, MY 1kamil.abdullah@mmu.edu ... of the model was determined through experiments because if the order is too low, the model ...

Research paper thumbnail of Consumers' E-commerce acceptance model: Antecedents of trust and satisfaction constructs

2012 IEEE Business, Engineering & Industrial Applications Colloquium (BEIAC), 2012

Are trust and satisfaction important in consumers' electronic commerce acceptance procedure?... more Are trust and satisfaction important in consumers' electronic commerce acceptance procedure? What are the antecedents of trust and satisfaction in this context? How do trust and satisfaction affect the Internet consumer's purchasing decision? To answer these questions, we develop a theoretical framework describing the trust-satisfaction based decision-making process a consumer uses when making a purchase from the internet, testing the proposed model using a correlation matrix and multiple regression technique on the Internet consumer purchasing behavior data collected from 450 respondents via questionnaire and considering the limitations of the model. The results of the study show that the Internet consumers' trust and satisfaction have strong impacts on their purchasing decisions. Security, privacy, and fulfillment/reliability have strong effects on the Internet consumers' trust and satisfaction from e-purchasing. Interestingly, disposition to trust, non-deception and third party seal did not strongly influence consumers' trust and satisfaction in ecommerce acceptance.

Research paper thumbnail of GIS Implementation in Malaysian Statutory Development Plan System

Concepts, Methodologies, Tools, and Applications

Research paper thumbnail of A qualitative exploration of Pakistan’s street children, as a consequence of the poverty-disease cycle

Infectious Diseases of Poverty, 2014

Research paper thumbnail of GIS application in monitoring development plan implementation in Malaysia: Weaknesses and potential

Monitoring of development plans implementation is gaining more attention than before by the plann... more Monitoring of development plans implementation is gaining more attention than before by the planning authorities in Malaysia. Pilot plan monitoring projects are being conducted in order to develop the most suitable monitoring mechanism. Since GIS use is widespread in ...

Research paper thumbnail of Investigation of the Causal Relationship Between Tracheotomy and Aspiration in the Acute Care Setting

The Laryngoscope, 2000

To investigate the causal relationship, if any, between tracheotomy and incidence of aspiration i... more To investigate the causal relationship, if any, between tracheotomy and incidence of aspiration in the acute care setting. Prospective, consecutive. Twenty adult patients evaluated between February 1997 and October 1999 participated. Criteria for inclusion were a dysphagia evaluation before tracheotomy, subsequent tracheotomy and placement of a tracheotomy tube, and then a repeat dysphagia evaluation after tracheotomy prior to decannulation. This permitted the causal relationship between tracheotomy and incidence of aspiration to be investigated. Differences between duration of tracheotomy placement and age were analyzed with the Student t test and for non-parametric nominal data the chi2 test was applied. No causal relationship between tracheotomy and aspiration was exhibited, as 19 of 20 (95%) subjects exhibited the same aspiration status before and after tracheotomy. All 12 (100%) subjects who aspirated before tracheotomy also aspirated after tracheotomy and 7 of 8 (88%) subjects who did not aspirate before tracheotomy also did not aspirate after tracheotomy (P > .05). In addition, no significant differences were observed between aspiration status and days since tracheotomy or age (P > .05). In the acute care setting, no causal relationship between tracheotomy and aspiration status was exhibited.

Research paper thumbnail of The effect of custom tray material type and fabrication technique on tensile bond strength of impression material adhesive systems

Journal of Oral Rehabilitation, 2003

The purpose of this investigation was to evaluate the tensile bond strengths of two impression ma... more The purpose of this investigation was to evaluate the tensile bond strengths of two impression material systems (polysulphide and polyvinyl siloxane) to two custom tray materials [autopolymerizing and visible light-cured (VLC) acrylic resin]. The effect of polymerizing the tray materials directly against wax spacer and tinfoil was evaluated for each material. Polymerizing tray materials against tinfoil significantly increased the bond strengths of polysulphide and polyvinyl siloxane impression materials to VLC and autopolymerizing acrylic resin tray materials. Polyvinyl siloxane VLC cured against tinfoil combination produced the strongest bond. The VLC resin tray material generated greater bond strength than autopolymerizing acrylic resin when polymerized against tinfoil. KEYWORDS: acrylic resin tray, bond strength of impression material to tray, custom tray bonding to impressions, polyvinylsiloxane adhesion to tray, visible light-cured resin tray

Research paper thumbnail of A cross-sectional study of canine dimorphism in establishing sex identity: comparison of two statistical methods

Journal of Oral Rehabilitation, 2008

The occurrence of canine tooth dimorphism in Indian subjects has been investigated and the use of... more The occurrence of canine tooth dimorphism in Indian subjects has been investigated and the use of two statistical methods of evaluation compared. These were the methods of N.G. Rao and co-workers published in 1988 and quadratic discriminant analysis for correct classification of sex. Parameters considered were (i) the mesiodistal width of maxillary and mandibular canines, (ii) the maxillary canine arch width (intercanine distance) and (iii) the mandibular canine arch width. The results indicated significant dimorphism of the maxillary and mandibular canine teeth. When the results of the arch widths were subjected to the two statistical methods, differing results were obtained in the accuracy of sex classification. The percentage of correct classifications of sex was higher when using quadratic discriminant analysis.

Research paper thumbnail of Late presentation of esophageal cancer: Observations in a multiracial South-East Asian population

Journal of Digestive Diseases, 2010

Patients with histologically proven ECA were recruited for the study. Patients' case notes, endos... more Patients with histologically proven ECA were recruited for the study. Patients' case notes, endoscopy and operating theater records were reviewed. All cases were histologically confirmed. RESULTS: A total of 143 patients with ECA was diagnosed between 1998 and 2003. The mean age of the patients was 63.1 Ϯ 12.1 years with a male : female ratio of 1.8:1. Of these 50.3 percent were Indians, 32.9 percent, Chinese and 16.8 percent Malays. The overall hospital-based prevalence rates per 100 000 admissions according to races were: Malay; 23.5, Chinese; 57.4 and Indian; 134.1. The location of the tumors was: upper; 16 (11.2%) middle; 52 (36.4%) and lower; 75 (52.4%). The histological type of ECA were: squamous cell carcinomas; 113 (79.0%) and adenocarcinomas; 30 (21.0%). The ECA stage at diagnosis, was: II; 18 (12.6%), III; 23 (16.1%) and IV; 102 (71.3%). Only 24 (16.8%) patients underwent surgery and13 (9.1%) were considered curative. Overall 114 (79.7%) patients underwent palliative endoscopic stenting and six (4.2%) were given other palliative therapy including radiotherapy. CONCLUSIONS: Squamous cell cancer was the predominant type. ECA presents late in our patients and only a minority of patients underwent curative surgery.

Research paper thumbnail of “Diagnosing” Saudi health reforms: is NHIS the right “prescription”?

The International Journal of Health Planning and Management, 2012

This paper outlines the health context of the Kingdom of Saudi Arabia (KSA). It reviews health sy... more This paper outlines the health context of the Kingdom of Saudi Arabia (KSA). It reviews health systems development in the KSA from 1925 through to contemporary New Health Insurance System (NHIS). It also examines the consistency of NHIS in view of the emerging challenges. This paper identifies the determinants and scope of contextual consistency. First, it indicates the need to evolve an indigenous, integrated, and comprehensive insurance system. Second, it highlights the access and equity gaps in service delivery across the rural and remote regions and suggests how to bring these under insurance coverage. Third, it suggests how inputs from both the public and private sectors should be harmonized - the "quality" of services in the private healthcare industry to be regulated by the state and international standards, its scope to be determined primarily by open-market dynamics and the public sector welfare-model to ensure "access" of all to essential health services. Fourth, it states the need to implement an evidence-based public health policy and bridge inherent gaps in policy design and personal-level lifestyles. Fifth, it points out the need to produce a viable infrastructure for health insurance. Because social research and critical reviews in the KSA health scenario are rare, this paper offers insights into the mainstream challenges of NHIS implementation and identifies the inherent weaknesses that need attention. It guides health policy makers, economists, planners, healthcare service managers, and even the insurance businesses, and points to key directions for similar research in future.

Research paper thumbnail of Barriers to the uptake of eye care services in developing countries: A systematic review of interventions

Health Education Journal, 2012

Objective: This research identifies effective and ineffective interventions for reducing barriers... more Objective: This research identifies effective and ineffective interventions for reducing barriers to the uptake of eye care services in developing countries. Design: Systematic literature review. Setting: Only research studies done in developing countries were included. Method: The review is restricted to English-language articles published between 1997 and 2007. It includes studies that reported randomized trials (controlled and uncontrolled) and surveys with some form of outcome measure, with or without process evaluation. The literature search was conducted on six electronic databases. Data were extracted and synthesized using a standard data extraction form. A narrative synthesis was carried out for the purpose of this review. The quality of the included trials was assessed by CRD guidelines and Crombie’s checklist. The applicability of research findings was evaluated by the RE-AIM model. Results: One randomized cluster trial and nine surveys were critically appraised. Three mul...

Research paper thumbnail of Hemoperitoneum after accidental dislodgement and subsequent replacement of PEG tube

Gastrointestinal Endoscopy, 2001

Research paper thumbnail of Real Time Principal Component Analysis

2019 IEEE 35th International Conference on Data Engineering (ICDE)

By processing the data in motion, real-time data processing enables us to extract instantaneous r... more By processing the data in motion, real-time data processing enables us to extract instantaneous results from online input data that ensures timely responsiveness to events as well as a much enhanced capacity to process large data sets. This is especially important when decision loops include querying and processing data on the web where size and latency considerations make it impossible to process raw data in real-time. This makes dimensionality reduction techniques, like principal component analysis (PCA), an important data preprocessing tool to gain insights into data. In this paper, we propose a variant of PCA, that is suited for real-time applications. In the real-time version of the PCA problem, we maintain a window over the most recent data and project every incoming row of data into lower dimensional subspace, which we generate as the output of the model. The goal is to minimize the reconstruction error of the output from the input. We use the reconstruction error as the termination criteria to update the eigenspace as new data arrives. To verify whether our proposed model can capture the essence of the changing distribution of large datasets in real-time, we have implemented the algorithm and evaluated performance against carefully designed simulations that change distributions of data sources over time in a controllable manner. Furthermore, we have demonstrated that our algorithm can capture the changing distributions of real-life datasets by running simulations on datasets from a variety of real-time applications e.g. localization, customer expenditure, etc. We propose algorithmic enhancements that rely upon spectral analysis to improve dimensionality reduction. Results show that our method can successfully capture the changing distribution of data in a real-time scenario, thus enabling real-time PCA.

Research paper thumbnail of Implementasi Model Pembelajaran Kooperatif Tipe STAD Dalam Meningkatkan Hasil Belajar Siswa Pendidikan Dasar

AL-ASASIYYA: Journal Of Basic Education

This study aims to determine the implementation of the STAD type cooperative learning model in im... more This study aims to determine the implementation of the STAD type cooperative learning model in improving the learning outcomes of basic education students. This study uses classroom action research with 15 students as subjects of Class IV SD Negeri Sebanjar, Alor Village, Northwest Alor District, East Nusa Tenggara, consisting of 7 males and 8 females. This research was carried out in two cycles, and each cycle was carried out in 3 meetings including tests at the end of each cycle. Data collection was carried out using learning outcomes tests at the end of each cycle, observation sheets for teacher and student activities carried out during the learning process and student response questionnaires. The collected data was then analyzed using descriptive analysis techniques. The results of this classroom action research analysis found that the implementation of the STAD Type Cooperative learning model for two cycles has been able to improve the learning outcomes of Class IV students at ...

Research paper thumbnail of Within-herd phenotypic and genetic trend lines for milk yield in Holstein-Friesian dairy cows

Journal of Cell and Animal Biology, Nov 30, 2007

A total of 937 pedigree, breeding and performance records of 567 Friesian cows at the Livestock E... more A total of 937 pedigree, breeding and performance records of 567 Friesian cows at the Livestock Experiment Station Bhunikey Dist. Kasur (Pakistan) spanning the years 1982-2001 were analyzed using Best Linear Unbiased Predictions procedure. Individual animal models were fitted to total milk yield from all lactations to estimate breeding values by Restricted Maximum Likelihood methodology. Milk yield and lactation length averaged 3391.66 ± 137.97 kg and 278.40 ± 90.17 days, respectively. The estimated breeding values for milk yield ranged from-354 to 503 kg. The corresponding values for the standing herd ranged from-209 to 294 kg. The genetic trend for milk yield was slightly positive indicating that the sires used during the last 20 years were of better breeding values. Phenotypic reduction in milk yield over time was observed, a probable reflection of the inability of the cows to adapt to the local environment and other environmental inadequacies.

Research paper thumbnail of Kuala Lumpur draft city plan 2020 local inquiry: an analysis of its shortcomings

Research paper thumbnail of Preferred fence design: a case study of selected communities in the Klang valley

Research paper thumbnail of Ebola, the killer virus

Infectious Diseases of Poverty, 2015

Research paper thumbnail of Constrained model predictive control of proton exchange membrane fuel cell

Journal of Mechanical Science and Technology, 2014

A constrained model predictive control (MPC) is designed to regulate the air flow rate of proton ... more A constrained model predictive control (MPC) is designed to regulate the air flow rate of proton exchange membrane fuel cell (PEMFC). Oxygen excess ratio, compressor flow rate and supply manifold pressure are constrained to avoid oxygen starvation, surge and choke phenomena. This is achieved by manipulating compressor voltage and stack current. The choice of the manipulated input to satisfy a constraint is investigated. Surge and choke avoidance is successful, when compressor voltage is manipulated. When stack current is utilized to satisfy surge and choke constraints, a large unrealistic current is needed. Oxygen starvation is successfully avoided utilizing stack current, while compressor voltage manipulation fails to prevent oxygen starvation. Thus, a current governor is implemented to handle oxygen starvation, while the compressor voltage is constrained to avoid surge and choke. Quadratic programming optimization, Laguerre and exponential weight function are employed to reduce the computational burden of the controller. The simulation results prove that the proposed controller managed to satisfy all constraints without any conflict.

Research paper thumbnail of Effects of diseased ECG on the robustness of ECG biometric systems

2010 IEEE EMBS Conference on Biomedical Engineering and Sciences (IECBES), 2010

This paper looks into the effects of diseased subjects on the recognition rate of an ECG biometri... more This paper looks into the effects of diseased subjects on the recognition rate of an ECG biometric system. A novel technique for feature extraction, linear predictive coding, is implemented along with neural networks for the classifier. Diseased ECG has been shown reduce the recognition rate of the system by only less than 1% and thus the system is robust towards diseased ECG. This allows for the system incorporating linear predictive coding to be used in practical situations where some users may not be aware of their health state and may have diseased ECG signals.

Research paper thumbnail of Analysis of effective channel placement for an EEG-based biometric system

2010 IEEE EMBS Conference on Biomedical Engineering and Sciences (IECBES), 2010

... 1, Khazaimatol S Subari#2, Justin Leo Cheang Loong∗3 and Nurul Nadia Ahmad#4 #Faculty of Engi... more ... 1, Khazaimatol S Subari#2, Justin Leo Cheang Loong∗3 and Nurul Nadia Ahmad#4 #Faculty of Engineering, Multimedia University, Cyberjaya, MY 1kamil.abdullah@mmu.edu ... of the model was determined through experiments because if the order is too low, the model ...

Research paper thumbnail of Consumers' E-commerce acceptance model: Antecedents of trust and satisfaction constructs

2012 IEEE Business, Engineering & Industrial Applications Colloquium (BEIAC), 2012

Are trust and satisfaction important in consumers' electronic commerce acceptance procedure?... more Are trust and satisfaction important in consumers' electronic commerce acceptance procedure? What are the antecedents of trust and satisfaction in this context? How do trust and satisfaction affect the Internet consumer's purchasing decision? To answer these questions, we develop a theoretical framework describing the trust-satisfaction based decision-making process a consumer uses when making a purchase from the internet, testing the proposed model using a correlation matrix and multiple regression technique on the Internet consumer purchasing behavior data collected from 450 respondents via questionnaire and considering the limitations of the model. The results of the study show that the Internet consumers' trust and satisfaction have strong impacts on their purchasing decisions. Security, privacy, and fulfillment/reliability have strong effects on the Internet consumers' trust and satisfaction from e-purchasing. Interestingly, disposition to trust, non-deception and third party seal did not strongly influence consumers' trust and satisfaction in ecommerce acceptance.

Research paper thumbnail of GIS Implementation in Malaysian Statutory Development Plan System

Concepts, Methodologies, Tools, and Applications

Research paper thumbnail of A qualitative exploration of Pakistan’s street children, as a consequence of the poverty-disease cycle

Infectious Diseases of Poverty, 2014

Research paper thumbnail of GIS application in monitoring development plan implementation in Malaysia: Weaknesses and potential

Monitoring of development plans implementation is gaining more attention than before by the plann... more Monitoring of development plans implementation is gaining more attention than before by the planning authorities in Malaysia. Pilot plan monitoring projects are being conducted in order to develop the most suitable monitoring mechanism. Since GIS use is widespread in ...

Research paper thumbnail of Investigation of the Causal Relationship Between Tracheotomy and Aspiration in the Acute Care Setting

The Laryngoscope, 2000

To investigate the causal relationship, if any, between tracheotomy and incidence of aspiration i... more To investigate the causal relationship, if any, between tracheotomy and incidence of aspiration in the acute care setting. Prospective, consecutive. Twenty adult patients evaluated between February 1997 and October 1999 participated. Criteria for inclusion were a dysphagia evaluation before tracheotomy, subsequent tracheotomy and placement of a tracheotomy tube, and then a repeat dysphagia evaluation after tracheotomy prior to decannulation. This permitted the causal relationship between tracheotomy and incidence of aspiration to be investigated. Differences between duration of tracheotomy placement and age were analyzed with the Student t test and for non-parametric nominal data the chi2 test was applied. No causal relationship between tracheotomy and aspiration was exhibited, as 19 of 20 (95%) subjects exhibited the same aspiration status before and after tracheotomy. All 12 (100%) subjects who aspirated before tracheotomy also aspirated after tracheotomy and 7 of 8 (88%) subjects who did not aspirate before tracheotomy also did not aspirate after tracheotomy (P > .05). In addition, no significant differences were observed between aspiration status and days since tracheotomy or age (P > .05). In the acute care setting, no causal relationship between tracheotomy and aspiration status was exhibited.

Research paper thumbnail of The effect of custom tray material type and fabrication technique on tensile bond strength of impression material adhesive systems

Journal of Oral Rehabilitation, 2003

The purpose of this investigation was to evaluate the tensile bond strengths of two impression ma... more The purpose of this investigation was to evaluate the tensile bond strengths of two impression material systems (polysulphide and polyvinyl siloxane) to two custom tray materials [autopolymerizing and visible light-cured (VLC) acrylic resin]. The effect of polymerizing the tray materials directly against wax spacer and tinfoil was evaluated for each material. Polymerizing tray materials against tinfoil significantly increased the bond strengths of polysulphide and polyvinyl siloxane impression materials to VLC and autopolymerizing acrylic resin tray materials. Polyvinyl siloxane VLC cured against tinfoil combination produced the strongest bond. The VLC resin tray material generated greater bond strength than autopolymerizing acrylic resin when polymerized against tinfoil. KEYWORDS: acrylic resin tray, bond strength of impression material to tray, custom tray bonding to impressions, polyvinylsiloxane adhesion to tray, visible light-cured resin tray

Research paper thumbnail of A cross-sectional study of canine dimorphism in establishing sex identity: comparison of two statistical methods

Journal of Oral Rehabilitation, 2008

The occurrence of canine tooth dimorphism in Indian subjects has been investigated and the use of... more The occurrence of canine tooth dimorphism in Indian subjects has been investigated and the use of two statistical methods of evaluation compared. These were the methods of N.G. Rao and co-workers published in 1988 and quadratic discriminant analysis for correct classification of sex. Parameters considered were (i) the mesiodistal width of maxillary and mandibular canines, (ii) the maxillary canine arch width (intercanine distance) and (iii) the mandibular canine arch width. The results indicated significant dimorphism of the maxillary and mandibular canine teeth. When the results of the arch widths were subjected to the two statistical methods, differing results were obtained in the accuracy of sex classification. The percentage of correct classifications of sex was higher when using quadratic discriminant analysis.

Research paper thumbnail of Late presentation of esophageal cancer: Observations in a multiracial South-East Asian population

Journal of Digestive Diseases, 2010

Patients with histologically proven ECA were recruited for the study. Patients' case notes, endos... more Patients with histologically proven ECA were recruited for the study. Patients' case notes, endoscopy and operating theater records were reviewed. All cases were histologically confirmed. RESULTS: A total of 143 patients with ECA was diagnosed between 1998 and 2003. The mean age of the patients was 63.1 Ϯ 12.1 years with a male : female ratio of 1.8:1. Of these 50.3 percent were Indians, 32.9 percent, Chinese and 16.8 percent Malays. The overall hospital-based prevalence rates per 100 000 admissions according to races were: Malay; 23.5, Chinese; 57.4 and Indian; 134.1. The location of the tumors was: upper; 16 (11.2%) middle; 52 (36.4%) and lower; 75 (52.4%). The histological type of ECA were: squamous cell carcinomas; 113 (79.0%) and adenocarcinomas; 30 (21.0%). The ECA stage at diagnosis, was: II; 18 (12.6%), III; 23 (16.1%) and IV; 102 (71.3%). Only 24 (16.8%) patients underwent surgery and13 (9.1%) were considered curative. Overall 114 (79.7%) patients underwent palliative endoscopic stenting and six (4.2%) were given other palliative therapy including radiotherapy. CONCLUSIONS: Squamous cell cancer was the predominant type. ECA presents late in our patients and only a minority of patients underwent curative surgery.

Research paper thumbnail of “Diagnosing” Saudi health reforms: is NHIS the right “prescription”?

The International Journal of Health Planning and Management, 2012

This paper outlines the health context of the Kingdom of Saudi Arabia (KSA). It reviews health sy... more This paper outlines the health context of the Kingdom of Saudi Arabia (KSA). It reviews health systems development in the KSA from 1925 through to contemporary New Health Insurance System (NHIS). It also examines the consistency of NHIS in view of the emerging challenges. This paper identifies the determinants and scope of contextual consistency. First, it indicates the need to evolve an indigenous, integrated, and comprehensive insurance system. Second, it highlights the access and equity gaps in service delivery across the rural and remote regions and suggests how to bring these under insurance coverage. Third, it suggests how inputs from both the public and private sectors should be harmonized - the "quality" of services in the private healthcare industry to be regulated by the state and international standards, its scope to be determined primarily by open-market dynamics and the public sector welfare-model to ensure "access" of all to essential health services. Fourth, it states the need to implement an evidence-based public health policy and bridge inherent gaps in policy design and personal-level lifestyles. Fifth, it points out the need to produce a viable infrastructure for health insurance. Because social research and critical reviews in the KSA health scenario are rare, this paper offers insights into the mainstream challenges of NHIS implementation and identifies the inherent weaknesses that need attention. It guides health policy makers, economists, planners, healthcare service managers, and even the insurance businesses, and points to key directions for similar research in future.

Research paper thumbnail of Barriers to the uptake of eye care services in developing countries: A systematic review of interventions

Health Education Journal, 2012

Objective: This research identifies effective and ineffective interventions for reducing barriers... more Objective: This research identifies effective and ineffective interventions for reducing barriers to the uptake of eye care services in developing countries. Design: Systematic literature review. Setting: Only research studies done in developing countries were included. Method: The review is restricted to English-language articles published between 1997 and 2007. It includes studies that reported randomized trials (controlled and uncontrolled) and surveys with some form of outcome measure, with or without process evaluation. The literature search was conducted on six electronic databases. Data were extracted and synthesized using a standard data extraction form. A narrative synthesis was carried out for the purpose of this review. The quality of the included trials was assessed by CRD guidelines and Crombie’s checklist. The applicability of research findings was evaluated by the RE-AIM model. Results: One randomized cluster trial and nine surveys were critically appraised. Three mul...

Research paper thumbnail of Hemoperitoneum after accidental dislodgement and subsequent replacement of PEG tube

Gastrointestinal Endoscopy, 2001