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Fulltext Removal behaviour of residual pollutants from biologically treated palm oil mill effluent by Pennisetum purpureum in constructed wetland

Ujang FA, Roslan AM, Osman NA, Norman A, Idris J, Farid MAA, et al.

Sci Rep, 2021 Sep 14;11(1):18257.
PMID: 34521938 DOI: 10.1038/s41598-021-97789-0

The reason for such enormous efforts in palm oil mill effluent research would be what has been singled out as one of the major sources of pollution in Malaysia, and perhaps the most costly and complex waste to manage. Palm oil mill final discharge, which is the treated effluent, will usually be discharged to nearby land or river since it has been the least costly way to dispose of. Irrefutably, the quality level of the treated effluent does not always satisfy the surface water quality in conformity to physicochemical characteristics. To work on improving the treated effluent quality, a vertical surface-flow constructed wetland system was designed with Pennisetum purpureum (Napier grass) planted on the wetland floor. The system effectively reduced the level of chemical oxygen demand by 62.2 ± 14.3%, total suspended solid by 88.1 ± 13.3%, ammonia by 62.3 ± 24.8%, colour by 66.6 ± 13.19%, and tannin and lignin by 57.5 ± 22.3%. Heat map depicted bacterial diversity and relative abundance in life stages from the wetland soil, whereby bacterial community associated with the pollutant removal was found to be from the families Anaerolineaceae and Nitrosomonadaceae, and phyla Cyanobacteria and Acidobacteria.
Extracellular matrix integrity affects the mechanical behaviour of in-situ chondrocytes under compression

Moo EK, Han SK, Federico S, Sibole SC, Jinha A, Abu Osman NA, et al.

J Biomech, 2014 Mar 21;47(5):1004-13.
PMID: 24480705 DOI: 10.1016/j.jbiomech.2014.01.003

Cartilage lesions change the microenvironment of cells and may accelerate cartilage degradation through catabolic responses from chondrocytes. In this study, we investigated the effects of structural integrity of the extracellular matrix (ECM) on chondrocytes by comparing the mechanics of cells surrounded by an intact ECM with cells close to a cartilage lesion using experimental and numerical methods. Experimentally, 15% nominal compression was applied to bovine cartilage tissues using a light-transmissible compression system. Target cells in the intact ECM and near lesions were imaged by dual-photon microscopy. Changes in cell morphology (N(cell)=32 for both ECM conditions) were quantified. A two-scale (tissue level and cell level) Finite Element (FE) model was also developed. A 15% nominal compression was applied to a non-linear, biphasic tissue model with the corresponding cell level models studied at different radial locations from the centre of the sample in the transient phase and at steady state. We studied the Green-Lagrange strains in the tissue and cells. Experimental and theoretical results indicated that cells near lesions deform less axially than chondrocytes in the intact ECM at steady state. However, cells near lesions experienced large tensile strains in the principal height direction, which are likely associated with non-uniform tissue radial bulging. Previous experiments showed that tensile strains of high magnitude cause an up-regulation of digestive enzyme gene expressions. Therefore, we propose that cartilage degradation near tissue lesions may be due to the large tensile strains in the principal height direction applied to cells, thus leading to an up-regulation of catabolic factors.
Dual photon excitation microscopy and image threshold segmentation in live cell imaging during compression testing

Moo EK, Abusara Z, Abu Osman NA, Pingguan-Murphy B, Herzog W

J Biomech, 2013 Aug 9;46(12):2024-31.
PMID: 23849134 DOI: 10.1016/j.jbiomech.2013.06.007

Morphological studies of live connective tissue cells are imperative to helping understand cellular responses to mechanical stimuli. However, photobleaching is a constant problem to accurate and reliable live cell fluorescent imaging, and various image thresholding methods have been adopted to account for photobleaching effects. Previous studies showed that dual photon excitation (DPE) techniques are superior over conventional one photon excitation (OPE) confocal techniques in minimizing photobleaching. In this study, we investigated the effects of photobleaching resulting from OPE and DPE on morphology of in situ articular cartilage chondrocytes across repeat laser exposures. Additionally, we compared the effectiveness of three commonly-used image thresholding methods in accounting for photobleaching effects, with and without tissue loading through compression. In general, photobleaching leads to an apparent volume reduction for subsequent image scans. Performing seven consecutive scans of chondrocytes in unloaded cartilage, we found that the apparent cell volume loss caused by DPE microscopy is much smaller than that observed using OPE microscopy. Applying scan-specific image thresholds did not prevent the photobleaching-induced volume loss, and volume reductions were non-uniform over the seven repeat scans. During cartilage loading through compression, cell fluorescence increased and, depending on the thresholding method used, led to different volume changes. Therefore, different conclusions on cell volume changes may be drawn during tissue compression, depending on the image thresholding methods used. In conclusion, our findings confirm that photobleaching directly affects cell morphology measurements, and that DPE causes less photobleaching artifacts than OPE for uncompressed cells. When cells are compressed during tissue loading, a complicated interplay between photobleaching effects and compression-induced fluorescence increase may lead to interpretations in cell responses to mechanical stimuli that depend on the microscopic approach and the thresholding methods used and may result in contradictory interpretations.
Fulltext The properties of chondrocyte membrane reservoirs and their role in impact-induced cell death

Moo EK, Amrein M, Epstein M, Duvall M, Abu Osman NA, Pingguan-Murphy B, et al.

Biophys J, 2013 Oct 1;105(7):1590-600.
PMID: 24094400 DOI: 10.1016/j.bpj.2013.08.035

Impact loading of articular cartilage causes extensive chondrocyte death. Cell membranes have a limited elastic range of 3-4% strain but are protected from direct stretch during physiological loading by their membrane reservoir, an intricate pattern of membrane folds. Using a finite-element model, we suggested previously that access to the membrane reservoir is strain-rate-dependent and that during impact loading, the accessible membrane reservoir is drastically decreased, so that strains applied to chondrocytes are directly transferred to cell membranes, which fail when strains exceed 3-4%. However, experimental support for this proposal is lacking. The purpose of this study was to measure the accessible membrane reservoir size for different membrane strain rates using membrane tethering techniques with atomic force microscopy. We conducted atomic force spectroscopy on isolated chondrocytes (n = 87). A micron-sized cantilever was used to extract membrane tethers from cell surfaces at constant pulling rates. Membrane tethers could be identified as force plateaus in the resulting force-displacement curves. Six pulling rates were tested (1, 5, 10, 20, 40, and 80 μm/s). The size of the membrane reservoir, represented by the membrane tether surface areas, decreased exponentially with increasing pulling rates. The current results support our theoretical findings that chondrocytes exposed to impact loading die because of membrane ruptures caused by high tensile membrane strain rates.
Is metal nanofluid reliable as heat carrier?

Nine MJ, Chung H, Tanshen MR, Osman NA, Jeong H

J Hazard Mater, 2014 May 30;273:183-91.
PMID: 24735805 DOI: 10.1016/j.jhazmat.2014.03.055

A pre- and post experimental analysis of copper-water and silver-water nanofluids are conducted to investigate minimal changes in quality of nanofluids before and after an effective heat transfer. A single loop oscillating heat pipe (OHP) having inner diameter of 2.4mm is charged with aforementioned nanofluids at 60% filling ratio for end to end heat transfer. Post experimental analysis of both nanofluids raises questions to the physical, chemical and thermal stability of such suspension for hazardless uses in the field of heat transfer. The color, deposition, dispersibility, propensity to be oxidized, disintegration, agglomeration and thermal conductivity of metal nanofluids are found to be strictly affected by heat transfer process and vice versa. Such degradation in quality of basic properties of metal nanofluids implies its challenges in practical application even for short-term heat transfer operations at oxidative environment as nano-sized metal particles are chemically more unstable than its bulk material. The use of the solid/liquid suspension containing metal nanoparticles in any heat exchanger as heat carrier might be detrimental to the whole system.
Analysis of the interface pressure exerted by the Chêneau brace in patients with double-curve adolescent idiopathic scoliosis

Ahmad A, Abu Osman NA, Mokhtar H, Mehmood W, Kadri NA

Proc Inst Mech Eng H, 2019 Sep;233(9):901-908.
PMID: 31244368 DOI: 10.1177/0954411919856144

The Chêneau brace has proven its effectiveness in treating the adolescent idiopathic scoliosis patients. However, no studies reported on the analysis of interface pressure in double-curve adolescent idiopathic scoliosis patients. In this study, we evaluated the interface pressure of the Chêneau brace action in double-curve adolescent idiopathic scoliosis patient treatment. A total of 72 (60 girls and 12 boys) patients aged 10 years and above participated in the study. The F-Socket transducers (9811E) were used to evaluate the pressure on the right thoracic and left thoracolumbar curves between normal and maximum strap tension and variation in these interface pressures with other tasks. Each patient was asked to do nine different tasks corresponding to daily activities, and the interface pressures for each activity were recorded for both normal and maximum tension. The resultant mean peak pressure in double-curve adolescent idiopathic scoliosis was higher for right thoracic curves than left thoracolumbar curves in all tasks. The pressure significantly increased at the task of maximal inspiration (p
Treatment stability of Milwaukee brace in idiopathic hyperkyphosis

Mehdikhani M, Behtash H, Ganjavian MS, Abu Osman NA, Khalaj N

Prosthet Orthot Int, 2014 Aug;38(4):316-20.
PMID: 23950552 DOI: 10.1177/0309364613499063

The Milwaukee brace is an efficient method for correcting hyperkyphosis before skeletal maturity. However, loss of correction in long-term follow-up is inevitable.
Fabrication and characterization of DLC coated microdimples on hip prosthesis heads

Choudhury D, Ay Ching H, Mamat AB, Cizek J, Abu Osman NA, Vrbka M, et al.

J Biomed Mater Res B Appl Biomater, 2015 Jul;103(5):1002-12.
PMID: 25220737 DOI: 10.1002/jbm.b.33274

Diamond like carbon (DLC) is applied as a thin film onto substrates to obtain desired surface properties such as increased hardness and corrosion resistance, and decreased friction and wear rate. Microdimple is an advanced surface modification technique enhancing the tribological performance. In this study, DLC coated microdimples were fabricated on hip prosthesis heads and their mechanical, material and surface properties were characterized. An Electro discharge machining (EDM) oriented microdrilling was utilized to fabricate a defined microdimple array (diameter of 300 µm, depth of 70 µm, and pitch of 900 µm) on stainless steel (SS) hip prosthesis heads. The dimpled surfaces were then coated by hydrogenated amorphous carbon (a-C:H) and tetrahedral amorphous carbon (Ta-C) layers by using a magnetron sputtering technology. A preliminary tribology test was conducted on these fabricated surfaces against a ceramic ball in simulated hip joint conditions. It was found that the fabricated dimples were perpendicular to the spherical surfaces and no cutting-tools wear debris was detected inside the individual dimples. The a-C:H and Ta-C coatings increased the hardness at both the dimple edges and the nondimpled region. The tribology test showed a significant reduction in friction coefficient for coated surfaces regardless of microdimple arrays: the lowest friction coefficient was found for the a-C:H samples (µ = 0.084), followed by Ta-C (µ = 0.119), as compared to the SS surface (µ = 0.248).
Prosthesis donning and doffing questionnaire: Development and validation

Abu Osman NA, Eshraghi A, Gholizadeh H, Wan Abas WAB, Lechler K

Prosthet Orthot Int, 2017 Dec;41(6):571-578.
PMID: 28190376 DOI: 10.1177/0309364617690397

OBJECTIVES: To develop a questionnaire that specifically evaluates the ability of trans-tibial amputees to don and doff a prosthesis and to investigate the psychometric properties of the newly developed questionnaire.
BACKGROUND: Prosthesis should be donned and doffed few times during the day and night; thus, it is important to measure ease of donning and doffing.
STUDY DESIGN: A cross-sectional study.
METHODS: The questionnaire was designed and evaluated by a group of experts. The final questionnaire was administered to 50 individuals with trans-tibial amputation. A test-retest study was also conducted on 20 amputees to assess the repeatability of questionnaire items.
RESULTS: The prosthesis donning and doffing questionnaire was developed and tested through a pilot study. Based on Kappa index, the questionnaire items showed correlation coefficients greater than 0.7, which indicate good reliability and repeatability. The majority of the participants had good hand dexterity (80%) and could perform all types of grasps. The mean satisfaction scores with donning and doffing were 69.9 and 81.4, respectively. Most of the respondents needed to don and doff the prosthesis 3.44 times per day. Based on a 7-point score, the total scores ranged between 3 and 7.
CONCLUSION: The prosthesis donning and doffing questionnaire items showed good psychometric properties. A scoring method was suggested based on the pilot sample, which requires further evaluation to be able to differentiate between more suspension types. A larger international multicenter evaluation is required in the future to measure the responsiveness of the scales. This questionnaire will be useful in the evaluation of the ability of amputees to don and doff a trans-tibial limb prosthesis. Clinical relevance Donning and doffing of prostheses are challenging tasks for many lower limb amputees. The prosthesis donning and doffing questionnaire, on its own or combined with other prosthetic evaluation questionnaires, has the potential to help manufacturers, clinicians, and researchers gain knowledge and improve the donning and doffing qualities of prostheses.
Factors Associated With How Long People Would Like to Live

Awang H, Nik Osman NA, Mansor N, Ab Rashid NF, Lih Yoong T

Int Q Community Health Educ, 2020 Jul;40(4):345-352.
PMID: 31876255 DOI: 10.1177/0272684X19896733

This article examined the factors of how long people would like to live involving 462 respondents aged 40 years and older in Malaysia. Data collected through an online self-administered survey indicated that 75% of the respondents would like to live at least 80 years and on average most people would like to live 81 years. Rural respondents, those who agreed that they have a loving family, those who agreed that they want to continue working for as long as they can, respondents who believed that they will not need long-term care at 65 years and older, and those who may consider living in an assisted living facility were more likely to want to live at least 80 years compared with respondents who did not agree. Efforts should be targeted at promoting healthy lifestyle and providing more employment opportunities for older persons.
Fulltext The validity and reliability of motion analysis in patellar tendon reflex assessment

Tham LK, Abu Osman NA, Wan Abas WA, Lim KS

PLoS One, 2013;8(2):e55702.
PMID: 23409022 DOI: 10.1371/journal.pone.0055702

The deep tendon reflex assessments that are essential to the accurate diagnosis of neurological or neuromuscular disorders are conducted subjectively in clinical neurology. Our aim was to assess deep tendon reflexes objectively with a new reflex quantification method.
Fulltext Correction to: Effectiveness and sustainability of a structured group-based educational program (MEDIHEALTH) in improving medication adherence among Malay patients with underlying type 2 diabetes mellitus in Sarawak State of Malaysia: study protocol of a randomized controlled trial

Ting CY, Adruce SAZ, Hassali MA, Ting H, Lim CJ, Ting RS, et al.

Trials, 2019 05 10;20(1):267.
PMID: 31077233 DOI: 10.1186/s13063-019-3348-x

After publication of the original article [1], the authors have notified us that there are changes to the primary outcome of the study, instrument, subject's inclusion criteria, the funding and acknowledgements. These changes were made during the recruitment of participants and after approved by the Medical Research and Ethics Committee (MREC), National Institutes of Health Malaysia, on 16th November 2018.
Identifying the barriers of smoking cessation and predictors of nicotine dependence among adult Malaysian smokers: A cross-sectional study

Marzo RR, El-Fass KA, Osman NA, Kyaw TM, Arivanandan PKA, Morgan LM, et al.

Tob Induc Dis, 2022;20:109.
PMID: 36530212 DOI: 10.18332/tid/154964

INTRODUCTION: Proper understanding of the prevalence and determinants of nicotine dependence is crucial for developing and implementing effective tobacco control interventions. The aim of the study was to identify the intrinsic and extrinsic barriers to smoking cessation, and to assess the association between nicotine dependence with demographic variables in Malaysia.
METHODS: A cross-sectional survey based on the Challenges to Stopping Smoking Scale (CSS-21) and Fagerström test for nicotine dependence (FTND) was performed on smoking Malaysian citizens aged ≥18 years, from February to June 2021.
RESULTS: A total of 1026 parents responded to the survey. As for the smoking dependence based on FTND, 39.1% suffered low-moderate dependence, while about 33.6% suffered moderate dependence. Only 1.8% suffered high dependence. Considering the barriers of quitting smoking based on CSS-21, the mean score of the intrinsic barriers domain was 5.7 ± 2.9, and for the extrinsic domain was 7.4 ± 4.0. The most common barrier reported in the intrinsic domain was the easy availability of cigarettes (69.8%), followed by experiencing withdrawal symptoms (68.5%). On the other hand, the most common barrier reported in the extrinsic domain was the belief in the capability of stopping smoking in the future (72.8%), followed by the fear of having side effects after stopping smoking (63.2%). Gender, race, education level, occupation, marital status, place of residence, and monthly income were also significantly associated with the FTND nicotine dependence category (all p<0.05). Pearson correlation analysis reported a positive association between intrinsic score (r=0.38), extrinsic score (r=0.43) and FTND score (all p<0.001).
CONCLUSIONS: Barriers to stopping smoking should be taken into consideration in initiatives to decrease smoking-related mortality. Vulnerable populations that are susceptible to high nicotine dependence should be given particular attention.
Fulltext Numerical investigation of the effect of cannula placement on thrombosis

Ong C, Dokos S, Chan B, Lim E, Al Abed A, Bin Abu Osman NA, et al.

Theor Biol Med Model, 2013;10:35.
PMID: 23680359 DOI: 10.1186/1742-4682-10-35

Despite the rapid advancement of left ventricular assist devices (LVADs), adverse events leading to deaths have been frequently reported in patients implanted with LVADs, including bleeding, infection, thromboembolism, neurological dysfunction and hemolysis. Cannulation forms an important component with regards to thrombus formation in assisted patients by varying the intraventricular flow distribution in the left ventricle (LV). To investigate the correlation between LVAD cannula placement and potential for thrombus formation, detailed analysis of the intraventricular flow field was carried out in the present study using a two way fluid structure interaction (FSI), axisymmetric model of a passive LV incorporating an inflow cannula. Three different cannula placements were simulated, with device insertion near the LV apex, penetrating one-fourth and mid-way into the LV long axis. The risk of thrombus formation is assessed by analyzing the intraventricular vorticity distribution and its associated vortex intensity, amount of stagnation flow in the ventricle as well as the level of wall shear stress. Our results show that the one-fourth placement of the cannula into the LV achieves the best performance in reducing the risk of thrombus formation. Compared to cannula placement near the apex, higher vortex intensity is achieved at the one-fourth placement, thus increasing wash out of platelets at the ventricular wall. One-fourth LV penetration produced negligible stagnation flow region near the apical wall region, helping to reduce platelet deposition on the surface of the cannula and the ventricular wall.
Fluid structure interaction simulation of left ventricular flow dynamics under left ventricular assist device support

Ong CW, Chan BT, Lim E, Abu Osman NA, Abed AA, Dokos S, et al.

Annu Int Conf IEEE Eng Med Biol Soc, 2012;2012:6293-6.
PMID: 23367368 DOI: 10.1109/EMBC.2012.6347433

For patient's receiving mechanical circulatory support, malfunction of the left ventricular assist device (LVADs) as well as mal-positioning of the cannula imposes serious threats to their life. It is therefore important to characterize the flow pattern and pressure distribution within the ventricle in the presence of an LVAD. In this paper, we present a 2D axisymmetric fluid structure interaction model of the passive left ventricle (LV) incorporating an LVAD cannula to simulate the effect of the LVAD cannula placement on the vortex dynamics. Results showed that larger recirculation area was formed at the cannula tip with increasing cannula insertion depth, and this is believed to reduce the risk of thrombus formation. Furthermore, we also simulated suction events (collapse of the LV) by closing the inlet. Vortex patterns were significantly altered under this condition, and the greatest LV wall displacement was observed at the part of the myocardium closest to the cannula tip.
Fulltext The use of fiber Bragg grating sensors in biomechanics and rehabilitation applications: the state-of-the-art and ongoing research topics

Al-Fakih E, Abu Osman NA, Mahamd Adikan FR

Sensors (Basel), 2012 Sep 25;12(10):12890-926.
PMID: 23201977 DOI: 10.3390/s121012890

In recent years, fiber Bragg gratings (FBGs) are becoming increasingly attractive for sensing applications in biomechanics and rehabilitation engineering due to their advantageous properties like small size, light weight, biocompatibility, chemical inertness, multiplexing capability and immunity to electromagnetic interference (EMI). They also offer a high-performance alternative to conventional technologies, either for measuring a variety of physical parameters or for performing high-sensitivity biochemical analysis. FBG-based sensors demonstrated their feasibility for specific sensing applications in aeronautic, automotive, civil engineering structure monitoring and undersea oil exploration; however, their use in the field of biomechanics and rehabilitation applications is very recent and its practicality for full-scale implementation has not yet been fully established. They could be used for detecting strain in bones, pressure mapping in orthopaedic joints, stresses in intervertebral discs, chest wall deformation, pressure distribution in Human Machine Interfaces (HMIs), forces induced by tendons and ligaments, angles between body segments during gait, and many others in dental biomechanics. This article aims to provide a comprehensive overview of all the possible applications of FBG sensing technology in biomechanics and rehabilitation and the status of ongoing researches up-to-date all over the world, demonstrating the FBG advances over other existing technologies.
Fulltext Techniques for Interface Stress Measurements within Prosthetic Sockets of Transtibial Amputees: A Review of the Past 50 Years of Research

Al-Fakih EA, Abu Osman NA, Mahmad Adikan FR

Sensors (Basel), 2016 Jul 20;16(7).
PMID: 27447646 DOI: 10.3390/s16071119

The distribution of interface stresses between the residual limb and prosthetic socket of a transtibial amputee has been considered as a direct indicator of the socket quality fit and comfort. Therefore, researchers have been very interested in quantifying these interface stresses in order to evaluate the extent of any potential damage caused by the socket to the residual limb tissues. During the past 50 years a variety of measurement techniques have been employed in an effort to identify sites of excessive stresses which may lead to skin breakdown, compare stress distributions in various socket designs, and evaluate interface cushioning and suspension systems, among others. The outcomes of such measurement techniques have contributed to improving the design and fitting of transtibial sockets. This article aims to review the operating principles, advantages, and disadvantages of conventional and emerging techniques used for interface stress measurements inside transtibial sockets. It also reviews and discusses the evolution of different socket concepts and interface stress investigations conducted in the past five decades, providing valuable insights into the latest trends in socket designs and the crucial considerations for effective stress measurement tools that lead to a functional prosthetic socket.
Fulltext Diet Composition of the Wild Stump-Tailed Macaque (Macaca arctoides) in Perlis State Park, Peninsular Malaysia, Using a Chloroplast tRNL DNA Metabarcoding Approach: A Preliminary Study

Osman NA, Abdul-Latiff MAB, Mohd-Ridwan AR, Yaakop S, Nor SM, Md-Zain BM

Animals (Basel), 2020 Nov 26;10(12).
PMID: 33255964 DOI: 10.3390/ani10122215

Understanding dietary diversity is a fundamental task in the study of stump-tailed macaque, Macaca arctoides in its natural habitat. However, direct feeding observation and morphological identification using fecal samples are not effective and nearly impossible to obtain in natural habitats because this species is sensitive to human presence. As ecological methods are challenging and time-consuming, DNA metabarcoding offers a more powerful assessment of the diet. We used a chloroplast tRNL DNA metabarcoding approach to identify the diversity of plants consumed by free-ranging M. arctoides in the Malaysia-Thailand border region located in Perlis State Park, Peninsular Malaysia. DNA was extracted from three fecal samples, and chloroplast tRNL DNA was amplified and sequenced using the Illumina MiniSeq platform. Sequences were analyzed using the CLC Genomic Workbench software. A total of 145 plant species from 46 families were successfully identified as being consumed by M. arctoides. The most abundant species were yellow saraca, Saraca thaipingensis (11.70%), common fig, Ficus carica (9.33%), aramata, Clathrotropis brachypetala (5.90%), sea fig, Ficus superba (5.44%), and envireira, Malmea dielsiana (1.70%). However, Clathrotropis and Malmea are not considered Malaysian trees because of limited data available from Malaysian plant DNA. Our study is the first to identify plant taxa up to the species level consumed by stump-tailed macaques based on a DNA metabarcoding approach. This result provides an important understanding on diet of wild M. arctoides that only reside in Perlis State Park, Malaysia.
Metabarcoding data analysis revealed the plant dietary variation of long-tailed macaque Macacafascicularis (Cercopithecidae, Cercopithecinae) living in disturbed habitats in Peninsular Malaysia

Osman NA, Abdul-Latiff MAB, Mohd-Ridwan AR, Yaakop S, Karuppannan KV, Md-Zain BM

Biodivers Data J, 2022;10:e89617.
PMID: 36761533 DOI: 10.3897/BDJ.10.e89617

The long-tailed macaque (Macacafascicularis) has a wide range in both Peninsular Malaysia and Borneo. Although the primates are especially vulnerable to habitat alterations, this primate lives in disturbed habitats due to human-induced land-use. Thus, this study presents a faecal metabarcoding approach to clarify the plant diet of long-tailed macaques from five locations in Peninsular Malaysia to represent fragmented forest, forest edge, island and recreational park habitats. We extracted genomic DNA from 53 long-tailed macaque faecal samples. We found 47 orders, 126 families, 609 genera and 818 species across these five localities. A total of 113 plant families were consumed by long-tailed macaques in Universiti Kebangsaan Malaysia, 61 in the Malaysia Genome and Vaccine Institute, 33 in Langkawi Island, 53 in Redang Island and 44 in the Cenderawasih Cave. Moraceae (33.24%) and Fabaceae (13.63%) were the most common families consumed by long-tailed macaques from the study localities. We found that habitat type impacted diet composition, indicating the flexibility of foraging activities. This research findings provide an understanding of plant dietary diversity and the adaptability of this macaque with the current alteration level that applies to long-tailed macaque conservation management interest in the future.
Molecular phylogeny confirms the subspecies delineation of the Malayan Siamang (Symphalangussyndactyluscontinentis) and the Sumatran Siamang (Symphalangussyndactylussyndactylus) based on the hypervariable region of mitochondrial DNA

Sariyati NH, Abdul-Latiff MAB, Aifat NR, Mohd-Ridwan AR, Osman NA, Karuppannan KV, et al.

Biodivers Data J, 2024;12:e120314.
PMID: 38707255 DOI: 10.3897/BDJ.12.e120314

Siamangs (Symphalangussyndactylus) are native to Peninsular Malaysia, Sumatra and southern Thailand and their taxonomical classification at subspecies level remains unclear. Morphologically, two subspecies were proposed as early as 1908 by Thomas namely Symphalangus s.syndactylus and Symphalanguss.continentis. Thus, this study aims to clarify the Siamang subspecies status, based on mtDNA D-loop sequences. Faecal samples were collected from wild Siamang populations at different localities in Peninsular Malaysia. A 600-bp sequence of the mitochondrial D-loop region was amplified from faecal DNA extracts and analysed along with GenBank sequences representing Symphalangus sp., Nomascus sp., Hylobates sp., Hoolock sp. and outgroups (Pongopygmaeus, Macacafascicularis and Papiopapio). The molecular phylogenetic analysis in this study revealed two distinct clades formed by S.s.syndactylus and S.s.continentis which supports the previous morphological delineation of the existence of two subspecies. Biogeographical analysis indicated that the Sumatran population lineage was split from the Peninsular Malaysian population lineage and a diversification occurrred in the Pliocene era (~ 3.12 MYA) through southward expansion. This postulation was supported by the molecular clock, which illustrated that the Peninsular Malaysian population (~ 1.92 MYA) diverged earlier than the Sumatran population (~ 1.85 MYA). This is the first study to use a molecular approach to validate the subspecies statuses of S.s.syndactylus and S.s.continentis. This finding will be useful for conservation management, for example, during Siamang translocation and investigations into illegal pet trade and forensics involving Malayan and Sumatran Siamangs.

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