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Fulltext Developing a web-based advisory expert system for implementing traffic calming strategies

Falamarzi A, Borhan MN, Rahmat RA

ScientificWorldJournal, 2014;2014:757981.
PMID: 25276861 DOI: 10.1155/2014/757981

Lack of traffic safety has become a serious issue in residential areas. In this paper, a web-based advisory expert system for the purpose of applying traffic calming strategies on residential streets is described because there currently lacks a structured framework for the implementation of such strategies. Developing an expert system can assist and advise engineers for dealing with traffic safety problems. This expert system is developed to fill the gap between the traffic safety experts and people who seek to employ traffic calming strategies including decision makers, engineers, and students. In order to build the expert system, examining sources related to traffic calming studies as well as interviewing with domain experts have been carried out. The system includes above 150 rules and 200 images for different types of measures. The system has three main functions including classifying traffic calming measures, prioritizing traffic calming strategies, and presenting solutions for different traffic safety problems. Verifying, validating processes, and comparing the system with similar works have shown that the system is consistent and acceptable for practical uses. Finally, some recommendations for improving the system are presented.
Fulltext Predicting the use of public transportation: a case study from Putrajaya, Malaysia

Borhan MN, Syamsunur D, Akhir NM, Yazid MR, Ismail A, Rahmat RA

ScientificWorldJournal, 2014;2014:784145.
PMID: 25110744 DOI: 10.1155/2014/784145

Putrajaya is a new federal administrative capital of Malaysia which has been set to achieve a 70% share of all travels by public transport in the city area. However, the current modal split between the public transport and private transport is 15:85. In order to understand travelers' willingness to use the public transport, a conceptual model has been developed to determine the factors that affect them to use the public transport instead of travelling in their own cars. Various variables such as service quality, environmental impact, attitude, and behavior intention were analyzed and tested using structural equation model (SEM). Results indicate that the service quality and attitude are found to have positive effects on the behavioral intention of taking the public transport. Other than this, this study also shows that the service quality and environmental impact have some positive influences on the attitude to using the public transport. However, environmental impact has no significant, positive, and direct effect on behavioral intention. The results of this study demonstrate that the model that was developed is useful in predicting the public transport and it could provide a more complete understanding of behavioral intention towards public transport use.
Fulltext Comparison of anterior and posterior trabecular bone microstructure of human mandible using cone-beam CT and micro CT

Ibrahim N, Parsa A, Hassan B, van der Stelt P, Rahmat RA, Ismail SM, et al.

BMC Oral Health, 2021 05 08;21(1):249.
PMID: 33964918 DOI: 10.1186/s12903-021-01595-z

BACKGROUND: The aim of this study was to compare the trabecular bone microstructures of anterior and posterior edentulous regions of human mandible using cone-beam computed tomography (CBCT) and micro computed tomography (µCT).
METHODS: Twenty volumes of interests consisting of six anterior and fourteen posterior edentulous regions were obtained from human mandibular cadavers. A CBCT system with a resolution of 80 µm (3D Accuitomo 170, J. Morita, Kyoto, Japan) and a µCT system with a resolution of 35 µm (SkyScan 1173, Kontich, Belgium) were used to scan the mandibles. Three structural parameters namely, trabecular number (Tb.N), trabecular thickness (Tb.Th), and trabecular separation (Tb.Sp) were analysed using CTAn software (v 1.11, SkyScan, Kontich, Belgium). For each system, the measurements obtained from anterior and posterior regions were tested using independent sample t-test. Subsequently, all measurements between systems were tested using paired t-test.
RESULTS: In CBCT, all parameters of the anterior and posterior mandible showed no significant differences (p > 0.05). However, µCT showed a significant different of Tb.Th (p = 0.023) between anterior and posterior region. Regardless of regions, the measurements obtained using both imaging systems were significantly different (p ≤ 0.021) for Tb.Th and Tb.N.
CONCLUSIONS: The current study demonstrated that only the variation of Tb.Th between anterior and posterior edentulous region of mandible can be detected using µCT. In addition, CBCT is less feasible than µCT in assessing trabecular bone microstructures at both regions.
The development of a tool to predict temperature-exposure of incinerated teeth using colourimetric and hydroxyapatite crystal size data

Rahmat RA, Humphries MA, Austin JJ, Linacre AMT, Self P

Int J Legal Med, 2021 Sep;135(5):2045-2053.
PMID: 33655354 DOI: 10.1007/s00414-021-02538-7

This study presents a novel tool to predict temperature-exposure of incinerated pig teeth as a proxy for understanding impacts of fire on human teeth. Previous studies on the estimation of temperature-exposure of skeletal elements have been limited to that of heat-exposed bone. This predictive tool was developed using a multinomial regression model of colourimetric and hydroxyapatite crystal size variables using data obtained from unheated pig teeth and teeth incinerated at 300 °C, 600 °C, 800 °C and 1000 °C. An additional variable based on the observed appearance of the tooth was included in the tool. This enables the tooth to be classified as definitely burnt (600 °C-1000 °C) or uncertain (27 °C/300 °C). As a result, the model predicting the temperature-exposure of the incinerated teeth had an accuracy of 95%. This tool is a holistic, robust and reliable approach to estimate temperature of heat-exposed pig teeth, with high accuracy, and may act as a valuable proxy to estimate heat exposure for human teeth in forensic casework.
A comparative study between xerographic, computer-assisted overlay generation and animated-superimposition methods in bite mark analyses

Tai MW, Chong ZF, Asif MK, Rahmat RA, Nambiar P

Leg Med (Tokyo), 2016 Sep;22:42-8.
PMID: 27591538 DOI: 10.1016/j.legalmed.2016.07.009

This study was to compare the suitability and precision of xerographic and computer-assisted methods for bite mark investigations. Eleven subjects were asked to bite on their forearm and the bite marks were photographically recorded. Alginate impressions of the subjects' dentition were taken and their casts were made using dental stone. The overlays generated by xerographic method were obtained by photocopying the subjects' casts and the incisal edge outlines were then transferred on a transparent sheet. The bite mark images were imported into Adobe Photoshop® software and printed to life-size. The bite mark analyses using xerographically generated overlays were done by comparing an overlay to the corresponding printed bite mark images manually. In computer-assisted method, the subjects' casts were scanned into Adobe Photoshop®. The bite mark analyses using computer-assisted overlay generation were done by matching an overlay and the corresponding bite mark images digitally using Adobe Photoshop®. Another comparison method was superimposing the cast images with corresponding bite mark images employing the Adobe Photoshop® CS6 and GIF-Animator©. A score with a range of 0-3 was given during analysis to each precision-determining criterion and the score was increased with better matching. The Kruskal Wallis H test showed significant difference between the three sets of data (H=18.761, p<0.05). In conclusion, bite mark analysis using the computer-assisted animated-superimposition method was the most accurate, followed by the computer-assisted overlay generation and lastly the xerographic method. The superior precision contributed by digital method is discernible despite the human skin being a poor recording medium of bite marks.
Integrating spectrophotometric and XRD analyses in the investigation of burned dental remains

Rahmat RA, Humphries MA, Austin JJ, Linacre AMT, Raven M, Self P

Forensic Sci Int, 2020 May;310:110236.
PMID: 32172179 DOI: 10.1016/j.forsciint.2020.110236

Heat alters colour and crystallinity of teeth by destruction of the organic content and inducing hydroxyapatite crystal growth. The colour and crystallite changes can be quantified using spectrophotometric and x-ray diffraction analyses, however these analyses are not commonly used in combination to evaluate burned dental remains. In this study, thirty-nine teeth were incinerated at 300-1000 °C for 15 and 30 min and then measured using a spectrophotometer and an x-ray diffractometer. Response variables used were lightness, L*, and chromaticity a* and b* and luminance (whiteness and yellowness) for colour, and crystal size for crystallinity. Statistical analysis to determine the attribution of these variables revealed yellowness and crystal size were significantly affected by temperature (p < 0.05), whilst duration of heat-exposure showed no significant effect. This study suggests the inclusion of both spectrophotometric and x-ray diffraction in investigating thermal-heated teeth is useful to accurately estimate the temperature teeth are exposed to.
Diagnostic models to predict nuclear DNA and mitochondrial DNA recovery from incinerated teeth

Rahmat RA, Humphries MA, Saedon NA, Self PG, Linacre AMT

Int J Legal Med, 2023 Sep;137(5):1353-1360.
PMID: 37306739 DOI: 10.1007/s00414-023-03017-x

Teeth are frequently used for human identification from burnt remains, as the structure of a tooth is resilient against heat exposure. The intricate composition of hydroxyapatite (HA) mineral and collagen in teeth favours DNA preservation compared to soft tissues. Regardless of the durability, the integrity of the DNA structure in teeth can still be disrupted when exposed to heat. Poor DNA quality can negatively affect the success of DNA analysis towards human identification. The process of isolating DNA from biological samples is arduous and costly. Thus, an informative pre-screening method that could aid in selecting samples that can potentially yield amplifiable DNA would be of excellent value. A multiple linear regression model to predict the DNA content in incinerated pig teeth was developed based on the colourimetry, HA crystallite size and quantified nuclear and mitochondrial DNA. The chromaticity a* was found to be a significant predictor of the regression model. This study outlines a method to predict the viability of extracting nuclear and mitochondrial DNA from pig teeth that were exposed to a wide range of temperatures (27 to 1000 °C) with high accuracy (99.5-99.7%).
Freeze-drying improves DNA yield from teeth

Rahmat RA, Humphries MA, Linacre AMT, Malik A, Saedon NA, Austin JJ

Forensic Sci Int, 2021 Jul 29;326:110938.
PMID: 34343942 DOI: 10.1016/j.forsciint.2021.110938

The common method of preparing teeth prior to DNA extraction involves cleaning, decontamination, drying and pulverisation. Moisture in post-mortem teeth can promote bacterial growth and hydrolytic damage that could contribute to DNA degradation, whilst also possibly reducing the efficiency of sample pulverisation and DNA release. Here we compared DNA extraction from pig teeth, with- and without freeze-drying, to examine the impact of removing moisture on DNA yield. Quantitative real-time polymerase chain reaction (qPCR) was used to quantify an 83 bp mitochondrial DNA fragment and two nuclear DNA fragments of 82 bp and 150 bp. The comparative results showed that sample preparation with freeze-drying resulted in a higher DNA yield without compromising the DNA quality. This study highlights the advantage of incorporating a freeze-drying to improve the DNA yield and minimising the loss of DNA during sample preparation of teeth.
Fulltext Engineering characterisation of epoxidized natural rubber-modified hot-mix asphalt

Al-Mansob RA, Ismail A, Yusoff NI, Rahmat RA, Borhan MN, Albrka SI, et al.

PLoS One, 2017;12(2):e0171648.
PMID: 28182724 DOI: 10.1371/journal.pone.0171648

Road distress results in high maintenance costs. However, increased understandings of asphalt behaviour and properties coupled with technological developments have allowed paving technologists to examine the benefits of introducing additives and modifiers. As a result, polymers have become extremely popular as modifiers to improve the performance of the asphalt mix. This study investigates the performance characteristics of epoxidized natural rubber (ENR)-modified hot-mix asphalt. Tests were conducted using ENR-asphalt mixes prepared using the wet process. Mechanical testing on the ENR-asphalt mixes showed that the resilient modulus of the mixes was greatly affected by testing temperature and frequency. On the other hand, although rutting performance decreased at high temperatures because of the increased elasticity of the ENR-asphalt mixes, fatigue performance improved at intermediate temperatures as compared to the base mix. However, durability tests indicated that the ENR-asphalt mixes were slightly susceptible to the presence of moisture. In conclusion, the performance of asphalt pavement can be enhanced by incorporating ENR as a modifier to counter major road distress.
Sex estimation of Malaysian sub-adults using craniometrics: A computed tomography study

Syed Mohd Hamdan SN, Rahmat RA, Abdul Razak F, Abd Kadir KA, Mohd Faizal Abdullah ER, Ibrahim N

Leg Med (Tokyo), 2023 Sep;64:102275.
PMID: 37229938 DOI: 10.1016/j.legalmed.2023.102275

Sex estimation is crucial in biological profiling of skeletal human remains. Methods used for sex estimation in adults are less effective for sub-adults due to varied cranium patterns during the growth period. Hence, this study aimed to develop a sex estimation model for Malaysian sub-adults using craniometric measurements obtained through multi-slice computed tomography (MSCT). A total of 521 cranial MSCT dataset of sub-adult Malaysians (279 males, 242 females; 0-20 years old) were collected. Mimics software version 21.0 (Materialise, Leuven, Belgium) was used to construct three-dimensional (3D) models. A plane-to-plane (PTP) protocol was utilised to measure 14 selected craniometric parameters. Discriminant function analysis (DFA) and binary logistic regression (BLR) were used to statistically analyze the data. In this study, low level of sexual dimorphism was observed in cranium below 6 years old. The level was then increased with age. For sample validation data, the accuracy of DFA and BLR in estimating sex improved with age from 61.6% to 90.3%. All age groups except 0-2 and 3-6 showed high accuracy percentage (≥75%) when tested using DFA and BLR. DFA and BLR can be utilised to estimate sex for Malaysian sub-adult using MSCT craniometric measurements. However, BLR showed higher accuracy than DFA in sex estimation of sub-adults.