Proses penuaan seringkali dikaitkan dengan kemerosotan sistem kognitif. Kemerosotan tersebut bermula seawal usia dua puluhan dan berterusan secara linear. Walau bagaimanapun, kesan penuaan ke atas ciri kehubungan antara kawasan otak masih belum difahami. Dalam kajian ini, pengimejan resonans magnet kefungsian (fMRI) digunakan untuk mengkaji kesan penuaan ke atas kehubungan otak yang terhasil daripada tugasan mengulang secara terbalik (BRT). Subjek normal dalam empat kumpulan umur iaitu 20-29 tahun (n=14), 30-39 tahun (n=14), 40-49 tahun (n=10) dan 50-65 tahun (n=14) mengambil bahagian dalam kajian ini. Stimulus BRT terdiri daripada satu siri lima perkataan yang diberi secara auditori. Pemetaan statistik berparameter (SPM) dan pemodelan sebab dan akibat dinamik (DCM) digunakan untuk menentukan pengaktifan dan kehubungan otak. Sebanyak 200 model kehubungan intrahemisfera dan 150 interhemisfera dibina bagi menguji kewujudan gandingan antara girus temporal superior (STG), girus Heschl (HG), talamus (TH) dan girus presentral (PCG) kesemua subjek. Keputusan DCM menunjukkan subjek keempat-empat kumpulan umur menggunakan kehubungan intrahemisfera yang sama semasa tugasan BRT. Kehubungan interhemisfera pula didapati berubah menjadi semakin kompleks apabila usia meningkat. Perubahan tersebut didapati bermula pada usia 40 tahun. Keputusan ini menyokong penemuan terdahulu bahawa penuaan menyebabkan perubahan pada sistem neuron otak seterusnya mempengaruhi pemprosesan kognitif.
MeSH terms: Ataxia Telangiectasia; Magnetic Resonance Imaging; Neurons; Magnets
This study aim to evaluate the effect of different angle on bone density estimation based on HU on CT and CBCT scanning. A phantom of jaw was scanned using CT and CBCT machine from different angle (0, 15 and 30 degrees). The data were transformed into DICOM format and loaded into MIMICS software for density measurement. The density was measured at 9.55 mm from cemento-enamel junction (CEJ) on every different angle scanning data. Then these data were grouped as Group A1, A2 and A3 for CBCT group (0, 15 and 30 degrees, respectively) and Group B1, B2 and B3 for CT group (0, 15 and 30 degrees, respectively). The differences between the groups and the references (0 degree scanning) are measured statistically using SPSS software. In the CBCT data, the density reading at 15 and 30 degrees are higher than 0 degree scanning (mean difference = -155.63±62.61, p=0.03, mean difference = -33.13±84.24, p=0.206 for 15 and 30 degrees scanning, respectively). In the CT data, the density at 15 and 30 degrees scanning is lower than at 0 degrees scanning (mean different: 84.49±46.76, p=0.09 and 15.09±23.61, p=0.532). The differences are not significant statistically. Compared with CT, the effect of different angle scanning on density estimation on CBCT is stronger. These results showed that different angle scanning produce more error on density estimation based on HU on CBCT compared with CT. This study demonstrated that the uses of a CBCT and CT for density monitoring to evaluate bone density of jaws are affected by angle scanning.
Cornsilk is traditionally used to treat illnesses related to kidney and as diuretic agent. The study was performed to evaluate the effectiveness of Malaysian cornsilk in elevating diuresis and their dose response relationship in normal Sprague-Dawley rat. The diuresis activity was determined by administered the rats with different dose treatments of 400, 500, 600, 700 and 800 mg/kg. Cumulative urine was significantly increased with the dosage levels (400-600 mg/ kg) ranging from 14.06 - 20.13 mL. Cumulative urine of aqueous extract of cornsilk (AEC) at 400 mg/kg (14.06 mL) and 500 mg/kg (15.21 mL) treatments found to be significantly lower than positive control (21.25 mL). In addition, Na+ content was significantly higher compared with negative control at dosages of 500, 600, 700 and 800 mg/kg. At any rate, K+ and Cl- content of all AEC treatments were not significantly different during 24 h monitoring. The pH values were increased paralleled with the increment of AEC dosages, though it was not significant. On the other result, the ED50 of AEC was observed at 454.10 mg/kg. Malaysian AEC had shown a mild diuretic activity in elevating urine and Na+ content at dosages from 500 to 800 mg/kg. Whilst, AEC also showed an effect of potassium sparing diuretics. Thus, it is suggested that Malaysian cornsilk can be used as an alternative natural diuretic agent.
Conventional two-dimensional (2D) treatment planning of intracavitary brachytherapy is still a common practice at the radiotherapy center. The purpose of this study was to evaluate the organ at risk (OAR) doses estimated based on International Commission on Radiation Units and Measurements (ICRU) reference-point in patients with cervical cancer treated with high-dose-rate (HDR) intracavitary brachytherapy (ICBT). Between January 2010 and April 2014, 21 cervical cancer patients were treated with 42 fractions of brachytherapy using tandem and ovoids and underwent post-implant two-dimensional (2D) radiograph scans. HDR brachytherapy was delivered to a dose of 18 Gy in two fractions. Using the Oncentra brachytherapy treatment planning system (BTPS) software version 4.1 (Nucletron, Netherlands), the bladder and rectum points were retrospectively reconstructed based on 42 orthogonal radiographs datasets. The ICRU bladder and rectum point doses were recorded. As for results, the mean percentage dose of rectum and bladder for selected patients treated with intracavitary brachytherapy treatment (ICBT) were 47.27 and 75.59%, respectively. Combinations of ovoid’s size, length of tandem and anatomy variation between each patient were factors that affected the dose to the OAR. Therefore, the ICRU reference points can still be used with the 2D brachytherapy treatment planning in evaluating the OAR doses.
This study was conducted to characterize the selected marine fish species using partial sequence of mtDNA 12S and 16S rRNA gene. PCR amplification of 12S and 16S rRNA generated PCR amplicons at 350 and 440 bp lengths, respectively. Sequence analysis was performed using BioEdit software. Phylogenetic tree was constructed using MEGA software. Two reference species have been used namely Gobio gobio (AB239596 and EF112528) and Pentapodus caninus (DQ533268 and DQ532933). Based on the result obtained, mtDNA 12S and 16S rRNA were found to be useful as molecular markers for fish species identification. These markers will provide correct identification of fish species when considered along with morphological characteristics.
The existing optimal design of the fixed sampling interval S2-EWMA control chart to monitor the sample variance of a process is based on the average run length (ARL) criterion. Since the shape of the run length distribution changes with the magnitude of the shift in the variance, the median run length (MRL) gives a more meaningful explanation about the in-control and out-of-control performances of a control chart. This paper proposes the optimal design of the S2-EWMA chart, based on the MRL. The Markov chain technique is employed to compute the MRLs. The performances of the S2-EWMA chart, double sampling (DS) S2 chart and S chart are evaluated and compared. The MRL results indicated that the S2-EWMA chart gives better performance for detecting small and moderate variance shifts, while maintaining almost the same sensitivity as the DS S2 and S charts toward large variance shifts, especially when the sample size increases.
Over the years, maximum likelihood estimation and Bayesian method became popular statistical tools in which applied to fit finite mixture model. These trends begin with the advent of computer technology during the last decades. Moreover, the asymptotic properties for both statistical methods also act as one of the main reasons that boost the popularity of the methods. The difference between these two approaches is that the parameters for maximum likelihood estimation are fixed, but unknown meanwhile the parameters for Bayesian method act as random variables with known prior distributions. In the present paper, both the maximum likelihood estimation and Bayesian method are applied to investigate the relationship between exchange rate and the rubber price for Malaysia, Thailand, Philippines and Indonesia. In order to identify the most plausible method between Bayesian method and maximum likelihood estimation of time series data, Akaike Information Criterion and Bayesian Information Criterion are adopted in this paper. The result depicts that the Bayesian method performs better than maximum likelihood estimation on financial data.
Previous studies on honey have shown its potential as an alternative approach in optimizing medical resources for periodontal treatment. However, to date, there has been no study published on the effects of honey on human periodontal ligament fibroblasts (HPDLFs). The aimed of this study was to investigate the effect of Tualang honey on HPDLF proliferation and alkaline phosphatase (ALP) level with an intention to establish honey as one of the natural products which may promote healing and regeneration of periodontium. The HPDLFs were cultured and treated with honey at four different concentrations (0.02, 0.3, 1 and 5%) in a 96-well plate and incubated at 37°C with 5% CO2. Proliferation test (MTT test) was assessed up to day 3 whereas ALP level (ALP assay) was assessed up to day 7. The αMEM supplemented with 10% FBS and 1% penicillin streptomycin was used as control. The results for MTT showed that the cell proliferation for 0.02% honey concentration was significantly higher (p<0.05) on day 3 whereas the proliferation were decreased for 1% honey and 5% honey concentration (p<0.05) than control on all the 3 days. There was increased in ALP level in a similar pattern for all concentration groups from day 0 to day 7 without any significant difference compared with control. Therefore, the present data suggests that Tualang honey stimulated HPDLF proliferation at low concentrations and has an inhibitory effect at high concentrations. However, its role in osteoblastic differentiation requires further investigation.
This study aimed to assess the effects of fresh, thermal drying method (vacuum oven drying), and nonthermal drying method (freeze drying) on the antioxidant activities of leaves and berries of Cayratia trifolia using ferric reducing antioxidant power (FRAP) and 1,1-diphenyl-1-picrylhydrazyl radical scavenging capacity (DPPH) assays. The total phenolic content (TPC) and flavonoid content (TFC) of the leaves and berries of C. trifolia were also measured. Based on the results obtained, the TPC, TFC, and antioxidant activities of the leaves and berries were arranged in the following order: freeze-dried sample with methanol extraction > vacuum-dried sample with methanol extraction > freeze-dried sample with water extraction > vacuum-dried sample with water extraction > fresh sample with methanol extraction > fresh sample with water extraction. The results showed a significant difference (p<0.05) between the fresh and dried samples. In conclusion, freeze drying was found to be a good method for maintaining TPC, TFC, and antioxidant activities by FRAP and DPPH methods in the leaves and berries of C. trifolia.
Alkaline phosphatase (ALP), tartrate-resistant acid phosphatase (TRAP) and aspartate aminotransferase (AST) activities were studied as biomarkers of canine movement. Root resorption was also evaluated in canines subjected to the orthodontic forces. Nineteen subjects randomly received 100 and 150 g force using self-ligating brackets (SLB) either on the right or left site of maxillary arch. Gingival crevicular fluid samples were collected at distal sites of canines for five consecutive weeks. The activities of ALP, TRAP and AST were assayed and measured spectrophotometrically. Canine movement was measured for five consecutive weeks while root resorption was monitored at baseline, week 0 and week 5 using periapical radiographs. In 100 g group, TRAP activity significantly increased in week 3-5 when compared to TRAP baseline activity. However, ALP and AST activities slightly increased. In 150 g group, ALP and TRAP activities slightly increased when compared with their baseline activities. However, AST significantly increased in week 5. Canine movement and root resorption were not significantly different (p<0.05) in both groups. A force of 100 and 150 g slightly increased the bone modeling process and resulted in similar canine movement and root resorption. Therefore, 100 g force could be an optimum force for canine retraction and is preferable (compared with 150 g force) in canine retraction using SLB.
Analysis of relationship between sea surface temperature (SST) and Chlorophyll-a (chl-a) improves our understanding on the variability and productivity of the marine environment, which is important for exploring fishery resources. Monthly level 3 and daily level 1 images of Moderate Resolution Imaging Spectroradiometer Satellite (MODIS) derived SST and chl-a from July 2002 to June 2011 around the archipelagic waters of Spermonde Indonesia were used to investigate the relationship between SST and chl-a and to forecast the potential fishing ground of Rastrelliger kanagurta. The results indicated that there was positive correlation between SST and chl-a (R=0.3, p<0.05). Positive correlation was also found between SST and chl-a with the catch of R. kanagurta (R=0.7, p<0.05). The potential fishing grounds of R. kanagurta were found located along the coast (at accuracy of 76.9%). This study indicated that, with the integration of remote sensing technology, statistical modeling and geographic information systems (GIS) technique were able to determine the relationship between SST and chl-a and also able to forecast aggregation of R. kanagurta. This may contribute in decision making and reducing search hunting time and cost in fishing activities.
Posidonomya is common in the Kubang Pasu and Singa Formations in northwest Peninsular Malaysia. It was discovered from the red mudstone layers (redbeds) in many localities in Langkawi Islands, Perlis and Kedah. Previous studies suggested that the age of Posidonomya ranged from Middle Devonian to Carboniferous. Posidonomya beds in Kedah and Perlis are located above the Tournaisian radiolarian chert layers. The age of Posidonomya from Peninsular Malaysia is comparable to those of Europe, Morocco, Turkey and South China which range from Tournaisian to Serpukhovian, Early Carboniferous. The fossil specimens exhibit morphological features closely related to Posidonomya becheri Bronn. Two taxa were identified namely Posidonomya becheri Bronn and Posidonomya cf. kochi (von Koenen). The occurrence of Posidonomya indicates that the age of the lower part of the Kubang Pasu and Singa Formations is Early Carboniferous. Its geographic distribution formed a wide paleobiogeographic province in the Paleo-Tethys. The province was located in the warm tropical-subtropical climatic zone. Therefore, Posidonomya can be a good indicator for warm climate. Its wide distribution and short stratigraphic range make it a good index fossil for the Early Carboniferous.
Termites are one of the social insects living in large colonies that can cause economic loss. The objective of this study was to estimate foraging territory of infested subterranean termites on building structure. A mark-recapture study was conducted on eight Coptotermes gestroi colonies located at selected infested building structures in Penang, Malaysia. From the foraging study, the population of C. gestroi was estimated to be within the range of 106,592±6,968 to 4,185,000±2,127,328. Additionally, the foraging territory was from 13 to 300 m2 of the infested building structures. Meanwhile the maximum foraging distance was from 4 to 30 m of the infested structures. The results indicated that each of the building structures was infested by a single colony. This study also showed that the triple mark recapture technique used to estimate the population size of the termite colony was capable of providing rough estimates of foraging population of C. gestroi.
One of the concerns of the air pollution studies is to compute the concentrations of one or more pollutants’ species in space and time in relation to the independent variables, for instance emissions into the atmosphere, meteorological factors and parameters. One of the most significant statistical disciplines developed for the applied sciences and many other disciplines for the last few decades is the extreme value theory (EVT). This study assesses the use of extreme value distributions of the two-parameter Gumbel, two and three-parameter Weibull, Generalized Extreme Value (GEV) and two and three-parameter Generalized Pareto Distribution (GPD) on the maximum concentration of daily PM10 data recorded in the year 2010 - 2012 in Pasir Gudang, Johor; Bukit Rambai, Melaka; and Nilai, Negeri Sembilan. Parameters for all distributions are estimated using the Method of Moments (MOM) and Maximum Likelihood Estimator (MLE). Six performance indicators namely; the accuracy measures which include predictive accuracy (PA), coefficient of determination (R2), Index of Agreement (IA) and error measures that consist of Root Mean Square Error (RMSE), Mean Absolute Error (MAE) and Normalized Absolute Error (NAE) are used to find the goodness-of-fit of the distribution. The best distribution is selected based on the highest accuracy measures and the smallest error measures. The results showed that the GEV is the best fit for daily maximum concentration for PM10 for all monitoring stations. The analysis also demonstrates that the estimated numbers of days in which the concentration of PM10 exceeded the Malaysian Ambient Air Quality Guidelines (MAAQG) of 150 mg/m3 are between ½ and 1½ days.
Four new 6-methoxy-tetrahydro-β-carboline derivatives (1-6- methoxy-1-phenyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole,2-6-methoxy-1-(4-methoxyphenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole, 3-6-methoxy-1-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole and 4-2-methoxy-4-(6-methoxy-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenol )were prepared via the Maillard reaction using 5-methoxytryptamine and various aldehydes in water. The synthesis reaction conditions were optimised in catalyst loading, temperature and time using LC-MS for optimum yields. Surface response methodology and contour plot was selected as an approach for optimisation. The optimum yield could be achieved below 50oC within 5 h at 7 mole % catalyst loading at yields > 70%. The β-carboline compounds produced were characterised using electrospray ionization mass spectrometry (ESI-MS) and electrospray tandem mass (ESI-MS/MS). The mass fragmentation patterns of this group of heterocyclic tetrahydro-ß-carboline compounds are described herein.
The aim of this study was to establish a simple, accurate and reproducible method for the identification and quantification of surfactin using high-performance liquid chromatography (HPLC). Previously reported method of identification and quantification of surfactin were time consuming and requires a large quantity of mobile phase. The new method was achieved by application of Chromolith® high performance RP-18 (100 × 4.6 mm, 5 μm) as the stationary phase and optimization of mobile phase ratio and flow rate. Mobile phase consisted of acetonitrile (ACN) and 3.8 mM trifluroacetic acid (TFA) solution of 80:20 ratio at flow rate of 2.2 mL/min was obtained as the optimal conditions. Total elution time of the obtained surfactin peaks was four times quicker than various methods previously reported in the literature. The method described here allowed for fine separation of surfactin in standard sample (98% purity) and surfactin in fermentation broth.
Length-weight relationship (LWR) and condition factor of seven fish species from the Temengor Reservoir, Peninsular Malaysia were analyzed. A total of 1155 individuals belonging to two families namely Nandidae and Cyprinidae were measured and weighed. The most highly represented family was Cyprinidae which comprised six species. Among these seven species, three species generally showed positive allometric growth, two species showed isometric growth and the other two species showed negative allometric growth. The exponent b value of LWR ranged between 2.601 (Oxygaster anomalura) and 3.157 (Cyclocheilichthys apogon) with a mean of 2.983. The lowest mean condition factor, K was recorded in O. anomalura (0.648 ± 0.131) while the highest value was observed in Pristolepis fasciata (2.194 ± 0.153). This study has contributed to the knowledge of fish populations in this economically important area that could assist fishery management scientists in carrying out future ecological studies in line with the strategies of conservation, restoration and management.
Minyak pati Goniothalamus ridleyi daripada sampel segar dan kering bahagian kulit batang, kayu, buah, akar dan
daun telah diekstrak menggunakan hidro penyulingan. Minyak pati tersebut telah dianalisis menggunakan kromatografi
gas (KG) kapilari dan kromatografi gas-spektrometer jisim (KG-SJ). Komposisi sebatian kimia dalam minyak pati telah
dikenal pasti secara perbandingan data spektrum jisim sampel dengan spektrum jisim yang ada dalam rujukan Wiley,
perbandingan pengiraan indeks penahanan dengan nilai kepustakaan dan ko-kromatografi bagi sesetengah sebatian
dengan sebatian autentik pada turus kapilari DB-5. Sebanyak 50 sebatian telah dikenal pasti dan mewakili 89.5% minyak
pati kulit batang segar G. ridleyi. Minyak pati daripada kulit batang segar kaya dengan sebatian linalool (15.2%) dan
sitronellal (10.9%). Sejumlah 47 sebatian telah dikenal pasti dan mewakili 90.1% jumlah minyak pati kayu segar yang
menunjukkan kehadiran sebatian utama β-eudesmol (27.1%) dan γ-eudesmol (20.8%). Sementara itu, minyak pati
daripada bahagian buah menunjukkan kehadiran 49 sebatian serta mewakili 89.8% jumlah minyak pati. Sebatian utama
dalam minyak pati buah adalah β-kubebena (20.7%) dan elemol (20.2%). Sebatian utama dalam sampel segar adalah
sama dengan sebatian utama dalam sampel kering, kecuali bahagian sampel kering didapati kaya dengan sebatiansebatian
seperti β-karyofilena, limonena, β-selinena, viridifloral, α-kopaena dan cyperena.
Penyelidikan ini dijalankan untuk menilai kesan penggunaan tiga spesies rumpai laut iaitu Ulva sp., Gracilaria sp. dan
Kappaphycus sp. sebagai agen penapis semula jadi untuk menstabilkan pengkulturan rotifer dengan menggunakan
petunjuk kaedah kuantitatif iaitu membandingkan nilai pertumbuhan seketika per hari rotifer Brachionus plicatilis. Kadar
pertumbuhan seketika per hari rotifer dengan penggunaan Ulva sp. (p<0.01), Gracilaria sp. (p<0.05) dan Kappaphycus
sp. (p<0.05) pada berat basah 7 g dalam 10 L air laut menunjukkan kesan yang ketara berbanding kawalan. Bagi
kesemua rumpai laut yang diuji, keputusan menunjukkan setelah tercapainya nilai min kadar pertumbuhan seketika per
hari rotifer yang tertinggi, penambahan jumlah berat penggunaan rumpai laut memberikan kesan penurunan kepada
kadar pertumbuhan seketika rotifer. Keputusan menunjukkan Ulva sp. sesuai digunakan sebagai penapis biologi.
Bencana banjir boleh menjejaskan kehidupan dan harta benda. Risiko kejadian banjir boleh diminimumkan jika amaran
awal dapat dikeluarkan. Di atas inisiatif ini, peramalan aliran sungai harian dijalankan di sebuah stesen aliran sungai
di Sungai Muda, Malaysia yang terletak di dataran banjir. Peramalan dengan mengaplikasikan pendekatan kalut
melibatkan dua langkah iaitu pembinaan semula ruang fasa dan peramalan. Pembinaan ruang fasa melibatkan satu
pemboleh ubah iaitu data aliran sungai yang dibina semula kepada m-dimensi dengan menggunakan nilai optimum
dimensi pembenaman daripada kaedah Cao dan variasi nilai dimensi pembenaman untuk pendekatan songsang. Hasil
daripada pembinaan ruang fasa ini digunakan untuk meramal aliran sungai dengan menggunakan kaedah peramalan
setempat. Hasil kajian menunjukkan data aliran Sungai Muda adalah bertelatah kalut berdasarkan analisis daripada
kaedah Cao. Keseluruhan hasil peramalan bagi kedua-dua kaedah dapat memberikan peramalan yang baik berdasarkan
pekali korelasi yang tinggi. Namun, kombinasi parameter asas bagi pendekatan songsang memberikan hasil peramalan
yang lebih baik. Oleh itu, pendekatan songsang boleh dicadangkan bagi meramal data aliran sungai harian dengan
tujuan memberikan maklumat penting mengenai sistem aliran sungai di dataran banjir terutamanya di Sungai Muda.
MeSH terms: Aspirin; Ataxia Telangiectasia; Esterases; Malaysia