Kajian mengenai penghasilan estolida berasaskan kepada asid risinoleik dan asid oleik telah dilakukan. Asid polihetero, asid 12-fosfotungstik dan asid silikotungstik telah digunakan sebagai mangkin dan tindak balas dilakukan pada suhu 60 atau 90ºC, selama 10 atau 24 jam. Nisbah mol antara asid risinoleik dan asid oleik ialah 2:1 dan peratus berat mangkin terhadap reaktan adalah 5%. Spektrum FTIR produk estolida telah dibandingkan dengan produk tindak balas yang menggunakan mangkin homogen asid perklorik. Pembentukan estolida ditunjukkan dengan kehadiran tiga puncak baru pada 1733 cm-1 untuk kumpulan berfungsi C=O ester, 967 cm-1 untuk -CH=CH- trans dan 1177 cm-1 untuk C-O-C. Spektrum FTIR yang serupa juga telah diperoleh untuk produk menggunakan mangkin homogen asid perklorik. Analisis LC-MS menunjukkan terbentuk tiga puncak baru monoestolida pada masa penahanan (Rt) 8.6 (m/z 577), 10.2 (m/z 559) dan 12.1 minit (m/z 561). Hasil kajian menunjukkan tindak balas kondensasi antara oleik-risinoleik dengan menggunakan asid perklorik, pepejal asid silikotungstik dan asid fosfotungstik sebagai mangkin berjaya menghasilkan estolida masing-masing dengan peratus hasil 70.2, 70.0 dan 60.8%.
Glutamatergic dysfunction has been suggested as a possible substrate of the pathophysiology of many neurodegenerative diseases, specifically since glutamatergic transmission is severely altered by the early degeneration of cortico-cortical connections and hippocampal projections in Alzheimer’s disease, schizophrenia and Huntington’s disease in humans. Of the multiple genes, vesicular glutamate transporters, glutamate receptors and excitatory amino acid transporters have a significant role in glutamatergic transmissions. The regional differences of glutamatergic neurons and glutamate receptor neurons suggest many glutamatergic projections in the avian brain. Glutamatergic target areas are expected to show high activity of glutamate transporters that remove the released glutamate from the synaptic clefts. The distribution of the glutamate-related genes indicates that many glutamatergic transmissions exist in the avian brain. This review provide insights of glutamatergic circuits in birds particularly in the pallial organization of glutamatergic neurons and connection with the striatum and hippocampal-septal pathway and comparison with those of mammalian brain which are responsible for Alzheimer’s disease, schizophrenia and Huntington’s disease in humans.
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Data bagi Sapindaceae dalam suatu plot kekal 50 ha di Hutan Simpan Pasoh, Negeri Sembilan, Malaysia telah diperoleh dari Institut Penyelidikan Hutan Malaysia (FRIM), Kepong dan telah diguna untuk menilai pengeluaran primer dan taburan famili. Lima bancian telah dijalankan dalam tahun 1985-2005 dan analisis data telah dijalankan ke atas bancian terakhir. Walau bagaimanapun perbandingan telah dibuat antara kelima-lima bancian untuk menentukan kevariabelan. Daripada bancian tahun 2005, 10 genus dan 18 spesies Sapindaceae telah direkodkan di dalam plot. Sejumlah 13360 dirian pokok telah dikira dan spesies yang paling banyak ialah Xerospermum noronhianum (7678 dirian). Jumlah biojisim bagi famili telah dianggarkan sebanyak 7.25 t/ha dan biojisim atas tanah tertinggi telah disumbangkan oleh X. noronhianum, dengan anggaran sebanyak 2.78 t/ha. Spesies ini juga mempunyai nilai keluasan pangkal tertinggi dengan 17.68 m2/ha. Anggaran biojisim untuk 20 tahun telah berkurangan secara signifikan (ANOVA, p<0.05) antara empat bancian. Genus yang mempunyai dirian tertinggi ialah Xerospermum (57.47%). Bagi melihat corak taburan, Indeks Taburan Morisita (Id) telah digunakan dan mendapati semua spesies mempunyai corak taburan secara rawak. Sebanyak 2292 dirian telah didapati mati (278/tahun) dan 1246 dirian baru direkodkan (172/tahun) pada tahun 2005. Secara keseluruhannya pertambahan saiz diameter bagi tempoh 20 tahun adalah sangat kecil iaitu 0.03 cm/tahun.
A 1 ha permanent plot was established in Bangi Permanent Forest Reserve for this study. A total of 1018 trees with a diameter at breast height (DBH) of 5 cm and above were identified, marked and measured. Their DBH ranged from 5 to 83.6 cm, where most trees fell into the 5 to 14.9 cm DBH or Class 1 (65.71%) and 1.57% of them fell into Class 7 with DBH over 65 cm. The five largest trees were from the dipterocarp family. Species with the highest Relative Dominance Value was Shorea acuminata with a value of 10.40. The total above ground biomass was 362.13 t/ha, which can be considered high for a twice-logged forest. The total basal area was 314.97 m2. The species diversity Shannon-Wiener index for this plot is H=6.99 with evenness of 0.852 and 0.85 with Brillouin’s Index. Species with the highest frequency (68.39%) and highest Importance Value Index (83.80%) was Antidesma cuspidatum. There were 171 species of trees representing 113 genera and 43 families plot. Wild fruit trees and trees with ethnobotanical potential were also identified. The results of this study indicated that this forest has high biomass content and high species diversity.
A number of n-type Si (100) samples were prepared into porous structures via electrochemical etching process, using an electrolyte solution; HF and ethanol. The morphological properties of the samples were observed under scanning electron microscope measurement. The results showed that the pore density, pore uniformity distribution and pore size of the porous Si samples increased with time of etching. In the next stage, H2O2 was introduced into the electrolyte solution in order to investigate its effect on the morphological properties of the porous Si. From the experiment, we found that H2O2 gave finer porous structure with highly symmetrical cubic shape on the surface. Besides, H2O2 promoted smoother surface of the pore walls. Hence, the results showed that such porous Si structure could be used as a better substrate for the subsequent layer, in particular for the growth of cubic material.
The present study reports on the fabrication of porous zinc oxide by wet chemical etching. ZnO thin films were deposited via radio-frequency magnetron sputtering on p-type silicon with (111) preferred orientation. The etchants used in the present work were 0.1% and 1.0% nitric acid (HNO3) solutions. ZnO were etched at various times and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy to allow the examination of their structural and optical properties. The XRD results revealed that the intensity of ZnO(002) decreased when the thin films were etched in varying HNO3 concentrations over different periods of time. The above observation is attributed to the dissolution of the ZnO(002). The SEM images showed that the thickness of the ZnO layers decreased over the etching time, which resulted from the isotropic etching by the HNO3 solution. The PL emission intensity initially increased with increasing etching time. However, with further etching of the samples, the PL spectra showed a decreasing trend in intensity as a result of the decrease in the surface-to-volume ratio. All results lead to the conclusion that 1.0% HNO3 has the capability to change the ZnO surface significantly.
Kajian ini dijalankan untuk menentukan komposisi proksimat dan juga kandungan asid lemak durian kuning (Durio graveolens Becc.) Sabah. Kandungan lembapan, abu, protein kasar, lemak kasar, serat kasar, karbohidrat dan asid lemak telah ditentukan. Keputusan analisis proksimat menunjukkan durian kuning Sabah mempunyai kandungan lembapan sebanyak 66.5%, protein 3.1%, lemak 5.5%, abu 1.1%, serat kasar 3.7% dan 20.2% karbohidrat. Sebanyak 13 komponen asid lemak telah dikenal pasti dengan peratusan asid lemak tepu adalah lebih rendah (30.3%) berbanding asid lemak tidak tepu (69.7%). Peratusan asid lemak tepu yang paling tinggi adalah asid miristik (14.5%) manakala asid laurik adalah terendah (1.3%). Untuk asid lemak tidak tepu pula, asid oleik paling tinggi (22.2%) manakala asid lemak miristoleik paling rendah (1.9%).
In this study, the in-vitro antifungal activity and phytochemical analysis of Schizophyllum commune extracts have been investigated. The antifungal activity was tested against 11 species of selected wood degrading fungi of rubberwood. The results showed that water, methanol and ethanol extracts significantly inhibited the growth of wood degrading fungi with minimum inhibitory concentration (MIC) ranges 0.16-5.00 μg/μL. P. sanguineus was found as the strongest wood degrading fungus where it required the highest concentration of S. commune crude extracts (≥ 5.00 μg/μL) to inhibit its mycelia growth. Phytochemicals analysis revealed that the extracts contained flavonoid, phenol and saponin. The methanol extracts of S. commune was then applied on the rubberwood blocks and found that the growth of P. sanguineus was inhibited effectively at 5.00 μg/μL.
Menopause is the most prevalent cause of accelerated bone loss in women. Biochemical markers of bone resorption can be used clinically to predict future bone loss. This study aimed to determine the level of bone resorption markers in healthy pre and postmenopausal Malay women and determine their association with the risk. A total of 150 healthy women were recruited for this study (51 pre and 99 postmenopausal subjects). Data on socioeconomic, lifestyle habit and clinical were gained by personal interview. Fasting serum was collected to measure both C-telopeptide (CTx) and N-telopeptide (NTx) of type 1 collagen. Both markers were highly correlated with each other (r=0.568, p<0.001). Both intra- and inter-assay coefficient of variations (CV) of NTx were higher than those of CTx (8% and 12% vs 6% and 5%). The mean CTx values of pre and postmenopausal subjects were comparable with the expected values (0.2833 (0.1769) ng/mL and 0.4323 (1.851) ng/mL compared with 0.287 and 0.438 ng/mL, respectively). The NTx value for premenopausal subjects were higher than the expected values (15.2 (8.10) compared to 12.6 (3.20) nM BCE). The median was 19.929 nM BCE. The mean CTx and NTx levels of postmenopausal subjects were significantly lower than premenopausal subjects (p<0.05). The risk factors for bone resorption in this population were duration of menopause, marital status, body mass index (BMI), physical activity and education level. In conclusion, postmenopausal women showed a higher bone resorption, indicating higher bone loss. Increasing education and physical activity intervention might be effective to ensure better health in Malaysian older population.
MeSH terms: Bone Diseases, Metabolic; Bone Resorption; Fasting; Female; Habits; Humans; Life Style; Malaysia; Menopause; Peptides; Risk Factors; Biomarkers; Exercise; Body Mass Index; Marital Status; Postmenopause; Collagen Type I
Sampel larutan kompleks La1-xSrxMnO3 (LSMO) dengan 0 ≤ x ≤ 0.25 telah disediakan menggunakan kaedah Pechini. Larutan LSMO seterusnya dimendapkan ke atas substrat kuarza menggunakan kaedah salutan berputar dan seterusnya disepuh lindap pada suhu 750°C selama satu jam. Corak pembelauan sinar-X bagi filem yang mengandungi Sr bersesuaian dengan LSMO berstruktur rombohedron . Morfologi permukaan filem menunjukkan struktur yang berlainan bagi nilai x yang berlainan dengan lebih banyak pembentukan rekahan permukaan filem dengan peningkatan Sr. Sifat magnet pada suhu bilik menunjukkan kewujudan lengkungan histeresis untuk kesemua sampel. Sampel filem nipis La1-xSrxMnO3 dengan x = 0.00, 0.05 dan 0.10 menunjukkan sifat feromagnet yang lemah manakala filem dengan x = 0.15, 0.20 dan 0.25 adalah bersifat paramagnet. Sampel dengan x = 0.10 mempunyai nilai pemagnetan yang paling tinggi pada medan 12 kOe iaitu 0.48 emu/g.
In competing risks analysis, the primary interest of researchers is the estimation of the net survival probability (NSP) if a cause of failure could be eliminated from a population. The Kaplan-Meier product-limit estimator under the assumption that the eliminated risk is non-informative to the other remaining risks, has been widely used in the estimation of the NSP. The assumption implies that the hazard of the remaining risks before and after the elimination are equal and it could be biased. This paper addressed this possible bias by proposing a non-parametric multistate approach that accounts for an informative eliminated risk in the estimation procedure, whereby the hazard probabilities of the remaining risks before and after the elimination of a risk are not assumed to be equal. When a non-informative eliminated risk was assumed, it was shown that the proposed multistate estimator reduces to the Kaplan-Meier estimator. For illustration purposes, the proposed procedure was implemented on a published dataset and the change in hazard after elimination of a cause is investigated. Comparing the results to those obtained from using the Kaplan-Meier method, it was found that in the presence of (both constant and non-constant) informative eliminated risk, the proposed multistate approach was more sensitive and flexible.
In this paper, we examined a model of cell invasion focusing on the wavefront of the neural crest (NC) cells in the case of Hirschsprung’s disease (HSCR). Hirschsprung’s disease (HSCR) is a congenital defect of intestinal ganglion cells and causes patients to have disorders in peristalsis. This simulation model was performed using the fractional differential equations (FDEs) based upon two basic cell functions. Here, we simulated the mathematical model in a one-dimensional setting, based on the fractional trapezoidal numerical scheme and the results showed an interesting outcome for the mobility of the cellular processes under crowded environments.
The nanometer size clusters are often present in ZnO. We have calculated the vibrational frequencies of zinc oxide by using the density-functional theory. We synthesized clusters of ZnO starting with ZnOn and continue with Zn2On, Zn3On and Zn4On with n = 1, 2, 3 and 4. By minimizing the energy of the Schrödinger equation, we found the bond lengths and the vibrational frequencies of each cluster. These calculated data are compared to the experimentally measured Raman spectra of ZnO4 to identify the clusters which exist in this material. The density-functional theory in the local density approximation (LDA) is used with double numerical basis set. From this calculation, we find that the bond length for the cluster of ZnO4 with tetrahedral symmetry (Td) is 1.923 Å and the vibrational frequencies are 94.4 cm-1 and 440.4 cm-1 with degeneracy of 3 each. We have made several clusters using zinc and oxygen atoms and have calculated the vibrational frequencies, degeneracies and intensities in each case.
Fusarium semitectum is a widespread species occurring in various types of substrate. Fifteen F. semitectum isolates were recovered from several types of vegetable fruits showing fruit rot symptoms, namely long bean (Vigna sesquilpedalis), okra (Abelmoschus esculentus), loofa (Luffa acutangula), bitter gourd (Momordica charantia), cucumber (Cucumis sativus) and green chilli (Capsicum annum). The identification of the F. semitectum isolates was based on morphological characteristics of macroconidia and microconidia, presence of mesoconidia and colony pigmentation. The isolates were then characterized using vegetative compatibility group (VCG) and sequencing of translation elongation factor-1α gene (TEF-1α). From VCG analysis, 11 isolates were assigned to six VCGs and another four isolates were self-incompatible. The results of the phylogenetic analysis using TEF-1α sequences showed that the isolates were phyogenetically distinct although the morphological characteristics were very similar and generally the grouping of the isolates was not according to the host. Both VCG and phylogenetic analyses indicated that F. semitectum isolates from vegetable fruits were highly variable which suggested that the isolates belong to a species complex.
Satu kajian penilaian kualiti ekosistem sungai di Sungai Kongkoi di Negeri Sembilan telah dijalankan dengan menggunakan makroinvetebrat bentik sebagai penunjuk biologi. Pensampelan telah dijalankan di 5 stesen yang telah dipilih dan tiga replikasi sampel air telah diambil untuk dianalisis. Makroinvertebrat bentik telah disampel dengan menggunakan jaring Surber pada tiga titik pensampelan yang berbeza. Pengukuran in situ telah dilakukan bagi parameter suhu, pH, oksigen terlarut (DO) dan kekonduksian dengan menggunakan meter YSI 556 MPS. Analisis makmal dilakukan
untuk parameter jumlah pepejal terampai (TSS), permintaan oksigen biokimia (BOD5), permintaan oksigen kimia (COD) dan ammoniakal-nitrogen (NH3-N). Berdasarkan kepada indeks kualiti air (WQI) dan pengkelasan sungai di Malaysia (NWQS), Sungai Kongkoi didapati mempunyai kualiti air yang baik dan berada dalam Kelas 1. Ujian ANOVA satu hala menunjukkan bahawa kebanyakan parameter kualiti air tidak berbeza dengan nyata di sepanjang stesen pensampelan (p>0.05, α=0.05). Sejumlah 2 filum, 3 kelas, 8 order, 32 famili dan 3228 individu makroinvertebrat bentik telah dikenal
pasti dan didominasi oleh famili Baetidae, Perlidae, Hydropsychidae dan Elmidae. Ujian faktor menunjukkan setiap famili di atas adalah paling sesuai digunakan sebagai penunjuk biologi di kawasan rekreasi.
Satu analisis penentuan parameter kualiti air yang penting untuk penilaian ekosistem cetek telah dilakukan menggunakan kaedah multivariat. Sebanyak 14 parameter kualiti air yang melibatkan komponen biologi, fizik dan kimia telah dikumpulkan setiap bulan selama satu tahun. Data dianalisis menggunakan ujian faktor yang melibatkan tiga proses iaitu mengenal pasti korelasi antara faktor, mengekstrak faktor dan seterusnya melihat kesan gabungan faktor-faktor tersebut. Proses pertama melibatkan pengelompokkan parameter yang berkorelasi kuat ke dalam faktor tersendiri dan mengeluarkan parameter yang mempunyai lebih daripada satu faktor. Analisis pengelasan agglomeratif hierarki (HACA) dan analisis diskriminan (DA) juga dilakukan untuk memperlihatkan kelompokan dan pengaruh faktor terhadap kualiti air tasik. Hasil analisis menunjukkan kualiti air Tasik Chini dipengaruhi oleh lebih daripada satu faktor. Hasil kajian menunjukkan komponen biologi dan kimia (nutrien) mempunyai pengaruh kuat dalam penentuan kualiti air tasik. Parameter berasaskan biologi iaitu BOD5, COD, klorofil a dan kimia (nitrat dan ortofosfat) adalah parameter yang
penting di Tasik Chini. Ketiga-tiga analisis yang dijalankan menunjukkan kepentingan penentuan komponen biologi dan kimia bagi menentukan kualiti air Tasik Chini.
Kejadian kebakaran hutan yang memberikan implikasi negatif terhadap ekosistem hutan, kepelbagaian biologi, kualiti udara dan struktur tanah dapat dikurangkan melalui sistem pengurusan bencana yang berkesan. Mekanisme pengurusan bencana dapat dibangunkan melalui sistem amaran awal yang tepat serta sistem penyampaian maklumat yang cekap. Penyelidikan ini cuba memberi tumpuan kepada pemetaan potensi kebakaran hutan serta penyampaian maklumat kepada
pengguna melalui aplikasi WebGIS. Teknologi georuang dan permodelan matematik digunakan bagi mengenal pasti, mengelas serta memetakan kawasan hutan yang berpotensi untuk terbakar. Permodelan model proses analitik hierarki (AHP) serta teknologi georuang yang merangkumi penderiaan jauh, sistem maklumat geografi (GIS) dan pengumpulan data lapangan secara digital telah digunakan untuk negeri Selangor. AHP adalah suatu teknik yang dapat memodel sesuatu
keputusan yang meliputi objektif menyeluruh, dalam kajian ini untuk mencari kawasan yang berpotensi berlakunya kebakaran hutan. Tiga kriteria iaitu bahan bakar, bentuk topografi dan faktor manusia telah dipilih untuk membina satu reka bentuk hierarki berstruktur yang setiapnya diberikan pemberat. Kemudian hierarki ini dianalisis melalui satu siri perbandingan berpasangan yang diproses secara matematik dan keutamaan diberikan kepada kedudukan yang tinggi untuk mencapai hasil sumbangan pakar yang terlibat secara langsung dengan operasi pemadaman kebakaran hutan
yang terdiri daripada pegawai Jabatan Bomba dan Penyelamat Malaysia juga dinilai dalam model ini. Hasil kajian mendapati 65% daripada keseluruhan Selangor berpotensi rendah untuk terbakar sementara kawasan seluas 32.83 km persegi iaitu di Bestari Jaya, Ulu Tinggi dan Kuala Langat berpotensi melampau terbakar. Paparan maklumat melalui aplikasi WebGIS ini merupakan satu pendekatan terbaik bagi membantu proses membuat keputusan pada tahap keyakinan yang tinggi dan hampir menyamai keadaan sebenar. Agensi yang terlibat dalam pengurusan bencana
seperti Jawatankuasa Pengurusan dan Bantuan Bencana (JPBB) Daerah, Negeri dan Pusat serta Jabatan Bomba dan Penyelamat Malaysia dapat menggunakan hasil akhir kajian ini sebagai persediaan menghadapi ancaman kebakaran hutan pada masa akan datang.
MeSH terms: Cuba; Malaysia; Methylglycosides; Geographic Information Systems; Tetrahydroisoquinolines
Infant mortality is one of the central public issues in most of the developing countries. In Malaysia, the infant mortality rates have improved at the national level over the last few decades. However, the issue concerned is whether the improvement is uniformly distributed throughout the country. The aim of this study was to investigate the geographical distribution of infant mortality in Peninsular Malaysia from the year 1970 to 2000 using a technique known as disease mapping. It is assumed that the random variable of infant mortality cases comes from Poisson distribution. Mixture models were used to find the number of optimum components/groups for infant mortality data for every district in Peninsular Malaysia. Every component is assumed to have the same distribution, but different parameters. The number of optimum components were obtained by maximum likelihood approach via the EM algorithm. Bayes theorem was used to determine the probability of belonging to each district in every components of the mixture distribution. Each district was assigned to the component that had the highest posterior probability of belonging. The results obtained were visually presented in maps. The analysis showed that in the early year of 1970, the spatial heterogeneity effect was more prominent; however, towards the end of 1990, this pattern tended to disappear. The reduction in the spatial heterogeneity effect in infant mortality data indicated that the provisions of health services throughout the Peninsular Malaysia have improved over the period of the study, particularly towards the year 2000.
We investigate unsteady flow of a thin film of Newtonian fluid around a symmetric slender dry patch moving with constant velocity on an inclined planar substrate, the flow being driven by a prescribed constant shear stress at the free surface of the film (which would be of uniform thickness in the absence of the dry patch). We obtain a novel unsteady travelling-wave similarity solution which predicts that the dry patch has a parabolic shape and that the film thickness increases monotonically away from the dry patch.
Struktur-nano TiO2 dengan pelbagai saiz dan bentuk telah disintesis melalui kaedah hidrotermal menggunakan serbuk nanozarah TiO2 sebagai prekursor. Sistem hidrotermal yang mudah, murah dan bebas templet pada suhu rawatan 180ºC, pengaruh medium alkali dengan penambahan NaOH dan KOH ke atas saiz, morfologi dan sifat fotovoltaik struktur-nano TiO2 telah dikaji. Sampel telah diperincikan oleh mikroskopi elektron transmisi (TEM), analisis penyebaran tenaga sinar-x (EDAX) manakala keupayaan fotovoltaik sel suria sensitif pewarna (DSSC) diukur menggunakan Gamry Potentiostat Series G-300. Hasil kajian dengan menggunakan agen alkali yang berlainan (NaOH dan KOH) jelas mempengaruhi morfologi TiO2 dan sel suria sensitif pewarna yang terdiri daripada struktur nanorod TiO2 menunjukkan keupayaan terbaik dengan voltan litar terbuka (Voc) sebanyak 416.8 mV, ketumpatan arus litar terbuka (Jsc) sebanyak 0.169 mA/cm2 dan kecekapan penukaran (η) sebanyak 0.0232% di bawah iluminasi lampu xenon AM 1.5.