Displaying publications 1 - 20 of 111 in total

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  1. Fulltext A hybrid digital-signature and zero-watermarking approach for authentication and protection of sensitive electronic documents
    Tayan O, Kabir MN, Alginahi YM
    ScientificWorldJournal, 2014;2014:514652.
    PMID: 25254247 DOI: 10.1155/2014/514652
    This paper addresses the problems and threats associated with verification of integrity, proof of authenticity, tamper detection, and copyright protection for digital-text content. Such issues were largely addressed in the literature for images, audio, and video, with only a few papers addressing the challenge of sensitive plain-text media under known constraints. Specifically, with text as the predominant online communication medium, it becomes crucial that techniques are deployed to protect such information. A number of digital-signature, hashing, and watermarking schemes have been proposed that essentially bind source data or embed invisible data in a cover media to achieve its goal. While many such complex schemes with resource redundancies are sufficient in offline and less-sensitive texts, this paper proposes a hybrid approach based on zero-watermarking and digital-signature-like manipulations for sensitive text documents in order to achieve content originality and integrity verification without physically modifying the cover text in anyway. The proposed algorithm was implemented and shown to be robust against undetected content modifications and is capable of confirming proof of originality whilst detecting and locating deliberate/nondeliberate tampering. Additionally, enhancements in resource utilisation and reduced redundancies were achieved in comparison to traditional encryption-based approaches. Finally, analysis and remarks are made about the current state of the art, and future research issues are discussed under the given constraints.
  2. Fulltext Determination of genetic aberrations and novel transcripts involved in the pathogenesis of oligodendroglioma using array comparative genomic hybridization and next generation sequencing
    Hassanudin SA, Ponnampalam SN, Amini MN
    Oncol Lett, 2019 Feb;17(2):1675-1687.
    PMID: 30675227 DOI: 10.3892/ol.2018.9811
    The aim of the present study was to determine the genetic aberrations and novel transcripts, particularly the fusion transcripts, involved in the pathogenesis of low-grade and anaplastic oligodendroglioma. In the present study, tissue samples were obtained from patients with oligodendroglioma and additionally from archived tissue samples from the Brain Tumor Tissue Bank of the Brain Tumor Foundation of Canada. Six samples were obtained, three of which were low-grade oligodendroglioma and the other three anaplastic oligodendroglioma. DNA and RNA were extracted from each tissue sample. The resulting genomic DNA was then hybridized using the Agilent CytoSure 4×180K oligonucleotide array. Human reference DNA and samples were labeled using Cy3 cytidine 5'-triphosphate (CTP) and Cy5 CTP, respectively, while human Cot-1 DNA was used to reduce non-specific binding. Microarray-based comparative genomic hybridization data was then analyzed for genetic aberrations using the Agilent Cytosure Interpret software v3.4.2. The total RNA isolated from each sample was mixed with oligo dT magnetic beads to enrich for poly(A) mRNA. cDNAs were then synthesized and subjected to end-repair, poly(A) addition and connected using sequencing adapters using the Illumina TruSeq RNA Sample Preparation kit. The fragments were then purified and selected as templates for polymerase chain reaction amplification. The final library was constructed with fragments between 350-450 base pairs and sequenced using deep transcriptome sequencing on an Illumina HiSeq 2500 sequencer. The array comparative genomic hybridization revealed numerous amplifications and deletions on several chromosomes in all samples. However, the most interesting result was from the next generation sequencing, where one anaplastic oligodendroglioma sample was demonstrated to have five novel fusion genes that may potentially serve a critical role in tumor pathogenesis and progression.
  3. Fulltext Translation and validation of the Malay post traumatic stress disorder checklist for civilians
    Rafidah Bahari, Muhammad N Mohamad Alwi, Muhammad R Ahmad, Ismail Mohd Saiboon
    ASEAN Journal of Psychiatry, 2015;16(2):203-211.
    MyJurnal
    There are a number of validated questionnaires available for the screening of Post-Traumatic Stress Disorder (PTSD), and the PTSD Checklist for Civilians is one of them. However, none was translated into the Malay Language and validated for use in the Malaysian population. The aim of this study is to translate and validate the Malay PTSD Checklist for Civilians (MPCL-C). Methods: The PCL-C was translated into the Malay Language and back-translated. The reliability and validity of the MPCL-C were then determined by administering them to those who presented at the emergency department for motor vehicle accident at least one month before. Results: The MPCL-C has good face and content validity. In terms of reliability, it is also good, with Chronbach’s alpha values of 0.90, 0.77, 0.75 and 0.74 for the full scale, re-experiencing, avoidance and arousal domains respectively. Conclusions: The MPCL-C is a valid and reliable instrument to screen for PTSD in motor vehicle accident victims for the studied population.
  4. Fulltext Pyrosequencing-based quantitative evaluation of P16 methylation in diffuse large b-cell lymphoma
    Mohd. Ridah L.J., Ismail A., A. Talib N., Muhammad N., Hussain F.A., Zainuddin N.
    Journal of Biomedical and Clinical Sciences, 2016;1(1):12-17.
    MyJurnal
    Introduction: Methylation of promoter region of p16 leading to gene silencing has been implicated ina wide range of malignancies including lymphomas. In diffuse large B cell lymphoma (DLBCL) particularly, a varying percentage of epigenetic inactivation of p16 promoter region was observed ranging from 16 -54%. However, quantitative analysis of p16 promoter methylation in DLBCL has not been extensively studied in Malaysia. Objective: This study aims to quantitatively analyse p16 methylation in DLBCL samples using pyrosequencing technique. Methods: Genomic DNA was extracted from 16 formalin-fixed paraffin-embedded lymphoma tissue blocks from patients diagnosed with DLBCL. Samples were retrieved from Hospital Tengku Ampuan Afzan, Pahang and Hospital Universiti Sains Malaysia, Kelantan. Primers were designed to amplify bisulfite-treated DNA targeting p16 promoter region. Methylation status of 7 CpG sites was determined by pyrosequencing. Results: All the 16 samples studied showed promoter methylation of p16. The range of mean methylation percentage was between 18 to 81%. Conclusion: The present study has successfully measured the level of methylation of p16 in all 7 CpG sites despite the limitation in sample size. Since p16 methylation is a common event in our series of DLBCL cases, it is worth including a larger sample size in future studies to increase the chance of finding a significant correlation with clinical parameters.
  5. Predicting Down syndrome and neural tube defects using basic risk factors
    Khattak MT, Supriyanto E, Aman MN, Al-Ashwal RH
    Med Biol Eng Comput, 2019 Jul;57(7):1417-1424.
    PMID: 30877513 DOI: 10.1007/s11517-019-01969-0
    Congenital anomalies are not only one of the main killers for infants but also one of the major causes of deaths under 5. Among congenital anomalies, Down syndrome or trisomy 21 (T-21) and neural tube defects (NTDs) are considered the most common. Expectant mothers in developing countries may not have access to or may not afford the advanced prenatal screening tests. To solve this issue, this paper explores the practicality of using only the basic risk factors for developing prediction models as a tool for initial risk assessment. The prediction models are based on logistic regression. The results show that the prediction models do not have a high balanced classification rate. However, these models can still be used as an effective tool for initial risk assessment for T-21 and NTDs by eliminating at least 50% of the cases with no or low risk. Graphical Abstract Prenatal Risk Assessment of Trisomy-21 and Neural Tube Defects.
  6. Fulltext The effect of flaxseed extract on skin elasticity of the healing wound in rabbits.
    Abdul Jabbar O, Kashmoola MA, Mustafa Al-Ahmad BE, Mokhtar KI, Muhammad N, Abdul Rahim R, et al.
    IIUM Medical Journal Malaysia, 2019;18(1):5-12.
    MyJurnal
    Management of disturbed wounds, large skin defects and the areas where skin tension precludes wound closure is of high clinical importance. Healing in wounds occurs through epithelization and contraction processes (second-intentions healing) that may result in certain undesirable complications including keloid and formation of a fragile epithelial layer.Materials and methods: 27 white New Zealand rabbit included in this study divided into 3 groups; one group of 9 rabbits received Flaxseed gel topically for three time intervals (1, 7, and 14 days); a second group received Fucidin cream as positive control, while a third group has not received any treatment as negative control, Skin elasticity measurements were performed using the DermaLab system. Results: Throughout the study, skin elasticity was significantly greater in Flaxseed group than in others. Flaxseed decrease elasticity value from (3.46 ± 2.05). Hence, Young's modulus of skin elasticity in flaxseed group was (2.46 ± 1.02) after 14 days (p = 0.003), while no significant differences were evident in both Fucidin group (1.16 ± 0.77) and non-treated group (1.86 ± 1.40) (p = 0.019), accordingly flaxseed extract more reproducible than other groups demonstrating comparable efficacy in skin elasticity and distensibility.Conclusions: This study showed the therapeutic effect of flaxseed on biologic tissue. Elasticity evaluation demonstrated increased density and firmness in the network of collagen fibers in the dermis and subcutis during wound healing process promise in generating therapeutic gel to be used in wound healing process.
  7. Osteoporotic fracture healing: potential use of medicinal plants from the tropics
    Abdul Jalil MA, Shuid AN, Muhammad N
    Curr Drug Targets, 2013 Dec;14(14):1651-8.
    PMID: 24354586
    With improvements in living standards and healthcare, life expectancy has been increasing dramatically in most parts of the world. These situations lead to the increase in the reported cases of geriatrics-related diseases such as hypogonadal osteoporosis with skeletal fracture being the ultimate outcome, which eventually causes significant morbidity and mortality. The deficient gonadal hormones, which are the main cause of hypogonadal osteoporosis, could be substituted with hormone replacement therapy to hinder bone loss. However, the artificial hormonal therapy has been linked to grievous conditions such as breast and prostate cancers. In view of the various adverse effects associated with conventional treatment, many researchers are now focusing on finding alternative remedies from nature. This article explores the possibilities of certain medicinal plants native to Malaysia that possess androgenic and antioxidant properties to potentially be used in the treatment of fracture due to osteoporosis in ageing people.
  8. Solid state bioconversion of oil palm biomass for ligninase enzyme production
    Alam MZ, Mahmat ME, Muhammad N
    Artif Cells Blood Substit Immobil Biotechnol, 2005;33(4):457-66.
    PMID: 16317964
    A laboratory-scale study of bioconversion of local lignocellulosic material, oil palm biomass (OPB) was conducted by evaluating the enzyme production through microbial treatment in solid state bioconversion (SSB). OPB in the form of empty fruit bunches (EFB) was used as a solid substrate and treated with the white-rot fungus, Phanerochaete chrysosporium, to produce ligninase. The results showed that the highest ligninase activity of 400.27 U/liter was obtained at day 12 of fermentation. While the optimum study indicated the enzyme production of 1472.8 U/liter with moisture content of 50%, 578.7 U/liter with 10% v/w of inoculum size, and 721.8 U/liter with co-substrate concentration of 1% (w/w) at days 9, 9 and 12 of fungal treatment, respectively. The parameters glucosamine and reducing sugar were observed to evaluate the growth and substrate utilization in the experiment.
  9. Fulltext Simulation of COVID-19 outbreaks via Graphical User Interface (GUI)
    Mohd Jamil N, Rosli N, Muhammad N
    J Public Health Res, 2021 Sep 24;11(1).
    PMID: 34558879 DOI: 10.4081/jphr.2021.2130
    BACKGROUND: This research aimed to model the outbreak of COVID-19 in Malaysia and develop a GUI-based model.

    DESIGN AND METHODS: The model is an improvement of the susceptible, infected, recovery, and death (SIRD) compartmental model.  The epidemiological parameters of the infection, recovery, and death rates were formulated as time dependent piecewise functions by incorporating the control measures of lockdown, social distancing, quarantine, lockdown lifting time and the percentage of people who abide by the rules. An improved SIRD model was solved via the 4th order Runge-Kutta (RK4) method and 14 unknown parameters were estimated by using Nelder-Mead algorithm and pattern-search technique. The publicly available data for COVID-19 outbreak in Malaysia was used to validate the performance of the model. The GUI-based SIRD model was developed to simulate the number of active cases of COVID-19 over time by considering movement control order (MCO) lifted date and the percentage of people who abide the rules.

    RESULTS: The simulator showed that the improved SIRD model adequately fitted Malaysia COVID-19 data indicated by low values of root mean square error (RMSE) as compared to other existing models. The higher the percentage of people following the SOP, the lower the spread of disease. Another key point is that the later the lifting time after the lockdown, the lower the spread of disease.

    CONCLUSIONS: These findings highlight the importance of the society to obey the intervention measures in preventing the spread of the COVID-19 disease.

  10. Fulltext Role of medicinal plants and natural products on osteoporotic fracture healing
    Abd Jalil MA, Shuid AN, Muhammad N
    Evid Based Complement Alternat Med, 2012;2012:714512.
    PMID: 22973405 DOI: 10.1155/2012/714512
    Popularly known as "the silent disease" since early symptoms are usually absent, osteoporosis causes progressive bone loss, which renders the bones susceptible to fractures. Bone fracture healing is a complex process consisting of four overlapping phases-hematoma formation, inflammation, repair, and remodeling. The traditional use of natural products in bone fractures means that phytochemicals can be developed as potential therapy for reducing fracture healing period. Located closely near the equator, Malaysia has one of the world's largest rainforests, which are homes to exotic herbs and medicinal plants. Eurycoma longifolia (Tongkat Ali), Labisia pumila (Kacip Fatimah), and Piper sarmentosum (Kaduk) are some examples of the popular ethnic herbs, which have been used in the Malay traditional medicine. This paper focuses on the use of natural products for treating fracture as a result of osteoporosis and expediting its healing.
  11. Fulltext Partial Annuloplasty Rings in the Repair of Functional Ischemic Mitral Regurgitation
    Kunwar MA, Muhammad I, Khan MN, Sumreen B, Soomro NA, Naseeb K, et al.
    Cureus, 2020 Jun 03;12(6):e8419.
    PMID: 32642335 DOI: 10.7759/cureus.8419
    Background Acute myocardial infarction (MI) is the leading cause of worldwide cardiac morbidities and mortalities. Mitral regurgitation (MR) is a common complication of MI. The severity of ischemic MR (IMR) can range widely, both clinically and hemodynamically. Mitral valve (MV) repair by lifting annuloplasty is a surgical procedure used to correct the pathology of IMR. The immediate outcomes of this technique have not yet been determined. The present study, therefore, evaluated the immediate results of MV annuloplasty performed to complement MV repair in patients with IMR. Methodology All adult patients with IMR who underwent lifting posterior mitral annuloplasty (LPMA) plus concomitant coronary artery bypass grafting (CABG) were included. Immediate outcomes were evaluated by transesophageal color Doppler echocardiography. The frequency of successful outcomes was compared in patients with different baseline characteristics. Results Posterior mitral annuloplasty was successful in 93.1% of patients, including in 92.8% of men and 94.1% of women. The percentages of successful immediate outcomes differed significantly in patients with and without diabetes and hypertension, and in patients with two- and three-vessel disease. Conclusion LPMA resulted in a high percentage of successful immediate outcomes in patients with IMR. Further studies should compare rates of immediate, intermediate, and late outcomes of this technique.
  12. Calixarene: A Versatile Material for Drug Design and Applications
    Hussain MA, Ashraf MU, Muhammad G, Tahir MN, Bukhari SNA
    Curr Pharm Des, 2017;23(16):2377-2388.
    PMID: 27779081 DOI: 10.2174/1381612822666160928143328
    The therapy of various diseases by the drugs entrapped in calixarene derivatives is gaining attraction of researchers nowadays. Calixarenes are macrocyclic nano-baskets which belong to cavitands class of host-guest chemistry. They are the marvelous hosts with distinct hydrophobic three dimensional cavities to entrap and encapsulate biologically active guest drugs. Calixarene and its derivatives develop inclusion complexes with various types of drugs and vitamins for their sustained/targeted release. Calixarene and its derivatives are used as carriers for anti-cancer, anti-convulsant, anti-hypertensive, anthelmentic, anti-inflammatory, antimicrobial and antipsychotic drugs. They are the important biocompatible receptors to improve solubility, chemical reactivity and decrease cytotoxicity of poorly soluble drugs in supramolecular chemistry. This review focuses on the calixarene and its derivatives as the state-of-the-art in host-guest interactions for important drugs. We have also critically evaluated calixarenes for the development of prodrugs.
  13. Assessment of denitrification potential for coastal and inland sites using groundwater and soil analysis: the multivariate approach
    Dahiru M, Abu Bakar NK, Yus Off I, Low KH, Mohd MN
    Environ Monit Assess, 2020 Apr 19;192(5):294.
    PMID: 32307605 DOI: 10.1007/s10661-020-08276-4
    In an effort to determine the reason behind excellent nitrate remediation capacity at Kelantan region, a multivariate approach is employed to evaluate extent to which the influence of sea on soil geochemical composition affect variation pattern of groundwater quality. The results obtained from geochemical analysis of paleo-beach soil in coastal site at Bachok revealed multiple redox activity at different soil strata, involving both heterotrophic and autotrophic denitrification. In soil and water analysis, eight of the fourteen hydro-geochemical parameters (conductivity, temperature, soil texture, oxidation reduction potential, pH, total organic carbon, Fe, Cu, Mn, Cl-, SO42-, NO2-, NO3- and PO43-) measured using standard procedures were subjected to multivariate analysis. Evaluation of general variation pattern across the area reveals that the principal component analysis (PCA), hierarchical cluster analysis (HCA) and linear discriminant analysis (LDA) are in consonance with one another on apportioning three parameters (SO42-, Cl- and conductivity) to the coastal sites and two parameters (Fe and NH4+ or NO3-) to inland sites. The step forward analysis of LDA reveals four parameters in order of decreasing significance as Cl-, Fe and SO42-, while the two-way HCA identifies three clusters on location basis, respectively. In addition to the significant data reduction obtained, the results indicate that proximity to sea and location/geological-based influence are more significant than temporal-based influence in denitrification. By extension, the research reveals that influence of labile portion of natural resources is explorable for broader application in other remediation strategies.
  14. Juvenile Pityriasis Rubra Pilaris in a 4-year-old Child Treated Successfully with Secukinumab
    Albela H, Lee WQ, Nordin SN, Gopinathan LP, A Ramli MN, Leong KF
    Indian J Dermatol, 2022;67(5):601-603.
    PMID: 36865822 DOI: 10.4103/ijd.ijd_1079_21
  15. The effects of Labisia pumila var. alata on bone markers and bone calcium in a rat model of post-menopausal osteoporosis
    Shuid AN, Ping LL, Muhammad N, Mohamed N, Soelaiman IN
    J Ethnopharmacol, 2011 Jan 27;133(2):538-42.
    PMID: 20971181 DOI: 10.1016/j.jep.2010.10.033
    AIM OF THE STUDY: Postmenopausal osteoporosis is mainly treated with estrogen replacement therapy (ERT). However, ERT causes side effects, mainly breast cancer, uterine cancer and thromboembolic problems. Labisia pumila var. arata (LPva), a herb with phytoestrogenic effects has the potential to be used as an alternative agent to ERT. This study was conducted to determine the effects of LPva on bone biochemical markers and bone calcium content in ovariectomised rats.
    MATERIALS AND METHODS: Thirty two Wistar rats were divided into 4 groups, with 8 rats in each group. The first group was sham operated (Sham), the second group was ovariectomised (OVX), the third (LPva) and fourth group (ERT) were also ovariectomised and given LPva 17.5 mg/kg and Premarin(®) 64.5 μg/kg, respectively. Blood samples were taken before and after treatment to measure osteocalcin and C-terminal telopeptide of type 1 collagen levels using ELISA while the fifth lumbar bone samples were taken to measure bone calcium content using the Atomic Absorption Spectrophotometer (AAS).
    RESULTS: The osteocalcin levels were significantly higher in both the LPva and ERT groups compared to the OVX group. The CTX levels were significantly lower in both the LPva and ERT groups compared to the OVX group. However, only the ERT group had significantly higher bone calcium level compared to the OVX group.
    CONCLUSION: The supplementation of 17.5 mg/kg of LPva to ovariectomised rats for 8 weeks was able to prevent the changes in bone biochemical markers but failed to prevent the bone calcium loss induced by ovariectomy.
  16. Beneficial effects of vitamin E isomer supplementation on static and dynamic bone histomorphometry parameters in normal male rats
    Mehat MZ, Shuid AN, Mohamed N, Muhammad N, Soelaiman IN
    J. Bone Miner. Metab., 2010 Sep;28(5):503-9.
    PMID: 20145960 DOI: 10.1007/s00774-010-0159-2
    Bone is a specialized connective tissue that functions as the load-bearing structure of the body. Free radicals may affect bone remodeling by regulating osteoclast activity in either the physiological or pathological condition. Vitamin E, a lipid-soluble antioxidant, has been demonstrated to offer protection against osteoporosis and to improve the bone material and structure of animal models. The aim of this study was to observe and compare the effects of alpha-tocopherol (alpha-tocopherol), delta-tocotrienol (delta-tocotrienol), and gamma-tocotrienol (gamma-tocotrienol) on the static and dynamic bone histomorphometric parameters in normal male rats. Thirty-two normal Sprague-Dawley male rats aged 3 months and weighing 200-250 g were randomly divided into four groups. The control group was supplemented with oral gavages of olive oil (vehicle), whereas the alpha-tocopherol, delta-tocotrienol, and gamma-tocotrienol groups were given oral gavages of 60 mg/kg alpha-tocopherol, delta-tocotrienol, and gamma-tocotrienol, respectively. The rats were injected twice with calcein to fluorochrome-label the bones. After 4 months of treatment, the rats were killed, and the left femurs were dissected out and prepared for bone histomorphometry. Both the static and dynamic parameters of the vitamin E-treated groups were better than those of the normal control group. Among the vitamin E-treated groups, the tocotrienol groups showed better histomorphometry results compared to the α-tocopherol group, with the γ-tocotrienol group demonstrating the best effects on both sets of parameters. We concluded that vitamin E can promote bone formation in normal rats, with gamma-tocotrienol being the most potent form of vitamin E.
  17. Vitamin E exhibits bone anabolic actions in normal male rats
    Shuid AN, Mehat Z, Mohamed N, Muhammad N, Soelaiman IN
    J. Bone Miner. Metab., 2010 Mar;28(2):149-56.
    PMID: 19779668 DOI: 10.1007/s00774-009-0122-2
    Recently, vitamin E has been found to promote the bone structure of nicotine-treated rats well above their baseline values, thus suggesting that vitamin E may have some anabolic action. A bone anabolic agent acts by improving the bone structure leading to stronger bone. To assess the possible anabolic action vitamin E on bone, we supplemented alpha-tocopherol (ATF) or gamma-tocotrienol (GTT) at 60 mg/kg or vehicle [normal control (NC) group] for 4 months to normal male rats and measured their bone structure and biomechanical properties. Histomorphometric analysis revealed that vitamin E-supplemented rats have better trabecular volume, thickness, number, and separation than rats receiving vehicle only. For the first time we reported that GTT improves all the parameters of bone biomechanical strength, while ATF only improved some of the parameters compared to the NC group. Vitamin E supplementation, especially with the gamma isomer, improves bone structure, which contributed to stronger bone. Therefore, vitamin E has the potential to be used as an anabolic agent to treat osteoporosis or as bone supplements for young adults to prevent osteoporosis in later years.
  18. The effect of vitamin E on basic fibroblast growth factor level in human fibroblast cell culture
    Rashid SA, Halim AS, Muhammad NA
    Med J Malaysia, 2008 Jul;63 Suppl A:69-70.
    PMID: 19024988
    Basic fibroblast growth factor (bFGF) is angiogenic and effective in down-regulating excess collagen production. The aim of this study is to evaluate the effectiveness of vitamin E (Tocotrienol Rich Fraction) in altering the level of bFGF, a cytokine involved in the scar formation process. In this model, normal human fibroblasts were treated with various concentrations of vitamin E at different time frames. The levels of bFGF were determined by Enzyme-Linked Immunosorbant Assay (ELISA). This study demonstrated that Tocotrienol Rich Fraction (TRF) stimulated bFGF production by fibroblast and postulate that vitamin E may decrease aberrant scar formation.
  19. Fulltext Synthesis of Highly Crystalline Multilayered Boron Niride Microflakes
    Ahmad P, Khandaker MU, Amin YM, Muhammad N
    Sci Rep, 2016;6:21403.
    PMID: 26892366 DOI: 10.1038/srep21403
    Boron niride microflakes of 2-5 μm in diameter and greater than 40 μm in length with multilayer structure and highly crystalline nature are synthesized in two states of catalysts and dual role of nitrogen at 1100 °C. Most of the microflakes are flat, smooth and vertically aligned with a wall-like view from the top. Transmission electron microscopy shows overlapped layers of microflakes with an interlayer spacing of 0.34 nm. The h-BN components of the synthesized microflakes are verified from B 1s and N1 s peaks at 190. 7 and 397.9 eV. Raman shift at 1370 (cm(-1)) and sharp peaks in the XRD pattern further confirm the h-BN phase and crystalline nature of the synthesized microflakes. Microflakes of h-BN with the above characteristics are highly desirable for the development of a solid state neutron detector with higher detection efficiency.
  20. Comparison of the fine-scale genetic structure of three dipterocarp species
    Takeuchi Y, Ichikawa S, Konuma A, Tomaru N, Niiyama K, Lee SL, et al.
    Heredity (Edinb), 2004 Apr;92(4):323-8.
    PMID: 14735142
    We investigated the fine-scale genetic structure of three tropical-rainforest trees, Hopea dryobalanoides, Shorea parvifolia and S. acuminata (Dipterocarpaceae), in Peninsular Malaysia, all of which cooccurred within a 6-ha plot in Pasoh Forest Reserve. A significant genetic structure was found in H. dryobalanoides, weaker (but still significant) genetic structure in S. parvifolia and nonsignificant structure in S. acuminata. Seeds of all three species are wind dispersed, and their flowers are thought to be insect pollinated. The most obvious difference among these species is their height: S. parvifolia and S. acuminata are canopy species, whereas H. dryobalanoides is a subcanopy species. Clear differences were also found among these species in their range of seed dispersal, which depends on the height of the release point; so taller trees disperse their seed more extensively. The estimates of seed dispersal area were consistent with the degree of genetic structure found in the three species. Therefore, tree height probably had a strong influence on the fine-scale genetic structure of the three species.
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