The deficiency in the human auditory system of individuals suffering from sensorineural hearing loss (SNHL) is known to be associated with the difficulty in detecting of various speech phonological features that are frequently related to speech perception. This study investigated the effects of speech articulation features on the amplitude and latency of cortical auditory evoked potential (CAEP) components. The speech articulation features included the placing contrast and voicing contrast. 12 Malay subjects with normal hearing and 12 Malay subjects with SNHL were recruited for the study. The CAEPs response recorded at higher amplitude with longer latency when stimulated by voicing contrast cues compared to that of the placing contrast. Subjects with SNHL elicited greater amplitude with prolonged latencies in the majority of the CAEP components in both speech stimuli. The existence of different frequency spectral and time-varying acoustic cues of the speech stimuli was reflected by the CAEPs response strength and timing. We anticipate that the CAEPs responses could equip audiologist and clinicians with useful knowledge, concerning the potential deprivation experience by hearing impaired individuals, in auditory passive perception. This would help to determine what type of speech stimuli that might be useful in measuring speech perception abilities, especially in Malay Malaysian ethic group, for choosing a better rehabilitation program, since no such study conducted for evaluating speech perception among Malaysian clinical population.
A novel silver nanoparticles (Ag NPs)-based optical sensing probe has been developed for the detection of Japanese Encephalitis virus (JEV). Ag NPs were initially deposited onto amine functionalized glass slides. Subsequently, JEV antibodies were self-assembled onto surfaces of Ag NPs to form optical sensing probes. The detection of JEV antigen was observed via changes in light absorbance by Ag NPs upon occurrence of JEV antigen-antibody bindings. A highly sensitive and rapid optical sensing probe for JEV antigen with a detection limit of 12.8 ng/mL (for S/N ratio = 3) and an analysis assay time of 1 h had been demonstrated.
MeSH terms: Amines; Antibodies, Viral; Antigens, Viral; Encephalitis Virus, Japanese; Encephalitis, Japanese; Glass; Silver; Metal Nanoparticles; Limit of Detection
Ammonium persulfate (APS)-initiated grafting of methacrylamide (MAM) onto chitosan was successfully prepared for the first time by free radical mechanism. Both chitosan and chitosan-graft-poly(methacrylamide) (chitosan-g-PMAM) were characterized using Fourier transform infrared spectroscopy (FTIR), solid state 13C NMR, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Important factors affecting graft copolymerization such as reaction time, temperature and concentrations of APS, MAM and chitosan were investigated and optimized to obtain maximum grafting parameters. The optimum values for grafting percentage and yield of graft copolymerization were achieved under the following conditions: chitosan (1 g), MAM (4 g), APS (0.6 g), time reaction (4 h) and temperature (70ºC).
Fusarium species are known to cause various diseases on plantations including fruits and vegetables. The most common Fusarium that can cause plant diseases are Fusarium proliferatum and Fusarium verticillioides. Ear rot disease on maize, wilt disease on cucurbits and fruit rot disease on tomato as well as banana are example of diseases caused by these two species. The objectives of this study were to identify F. proliferatum and F. verticillioides based on species-specific primers and polymerase chain reaction (PCR) amplification and to evaluate the genetic diversity of both species based on microsatellite markers. Fifty isolates of Fusarium species that were previously collected throughout Malaysia from different hosts were identified by using species-specific PCR amplification. Twenty-nine isolates were identified as F. proliferatum and 21 isolates were identified as F. verticillioides based on species-specific primer. The genetic diversity of all the fungal isolates was evaluated by using microsatellite analysis with six established primers. Five out of six primers amplified polymorphic bands with the most effective primer showing high polymorphism were (AG)7C and (TCC)5 meanwhile one primer (TTTC)4 gave negative result with no band amplified. The phylogenetic tree that was constructed showing two different clades distinguished between F. proliferatum and F. verticillioides.
Kinetin has been reported to exert inhibitory effect when used in tissue culture and in some cases reverse the action of auxin and cause growth inhibition and retardation of root formations. Kinetin also acts as ‘mitotic poison’, mimicking the effect of pesticides and toxic chemicals and interferes in mitosis mechanism of plants. The effect of kinetin on size of cell and nucleus as well as chromosome behaviour in root tip meristems of Agapanthus praecox ssp. minimus was studied. The results showed that prolong exposure to kinetin caused chromosome abnormalities to occur more frequently. Chromosome breakage yielded fragmented chromosomes, while abnormal spindle fibers caused delay in chromosome movement, termed as laggard chromosomes. Abnormal nucleus was also observed with kinetin treatments, such as micronucleus, binucleated and tripolar cells.
The intra- and inter-specific variation of Acetes shrimps were evaluated based on samples collected from in-shore catches and off-shore trawling around the west coast of Peninsular Malaysia. Species captured were identified as Acetes indicus, A. serrulatus, A. japonicus and A. sibogae. A region of the mitochondrial cytochrome c oxidase subunit I (COI) gene comprising 552 base pairs (bp) was amplified from 159 Acetes specimens. The sequence alignment analysis generated phylogenetic trees which depicted the four major clades that were consistent with the species identified morphologically. These four species varied considerably for haplotype and nucleotide diversity, with A. indicus and A. serrulatus showing different demographic histories. Furthermore, the observation of two clades in the A. indicus and A. sibogae lineages, with relatively high levels of intraspecific divergence, suggests that cryptic diversity is possibly present in these two taxa. This study has contributed to the knowledge of the distribution patterns and molecular phylogenetics of four Acetes spp. in the Straits of Malacca.
MeSH terms: Animals; Electron Transport Complex IV; Demography; Haplotypes; Malaysia; Mitochondria; Nucleotides; Phylogeny; Sequence Alignment; Base Pairing; Decapoda (Crustacea)
This study describes the development of a multimedia environmental fate and transport model of dichlorodiphenyltrichloroethane (DDT) at Sungai Sayong watershed. Based on the latest estimated DDT emission, the DDT concentrations in air, soil, water and sediment as well as the transfer processes were simulated under the equilibrium and steady-state assumption. Model predictions suggested that soil and sediment was the dominant sink of DDT. The results showed that the model predicted was generally good agreement with field data. Compared with degradation reaction, advection outflow was more important processes occurred in the model. Sensitivities of the model estimates to input parameters were tested. The result showed that vapour pressure (Ps) and organic carbon water partition coefficient (KOC) were the most influential parameters for the model output. The model output-concentrations of DDT in multimedia environment is very important as it can be used in future for human exposure and risk assessment of organochlorine pesticides (OCPs) at Sungai Sayong Basin.
This paper had selected watermifoil (Myriophyllum veticillatum Linn.), softstem bulrush (Scirpus validus Vahl) and yellow-flowered iris (Iris wilsonii), in showing the water purification through different configuration. AFIs with different combination of aquatic plants were set up to purify the water quality for 50 days. This paper aimed to evaluate chemical and vegetative characteristics of each type of plant and also to find configuration of aquatic plants to maximize the contaminants removal efficiency by artificial floating island (AFI). The result indicated that the trophic waterbody promote the growth of plants and all of the AFIs have the ability to purify water and reduce contaminants. However, the most effective way is by combination of these three aquatic plants which has strong capacity to remove COD, NO3-, total nitrogen, total phosphorous and improve pH levels. Watermifoil (Myriophyllum verticillatum Linn.) is better than yellow-flowered iris (Iris wilsonii) and softstem bulrush (Scirpus validus Vahl) in disposing water pollutants.
MeSH terms: Nitrogen; Phosphorus; Water; Water Pollutants; Water Purification; Cyperaceae; Iris Plant; Water Quality; Islands
This paper reports the water quality of Murum Hydroelectric Reservoir, eight months after impoundment of the dam. A total of nine stations were selected in the reservoir. Temperature, pH, dissolved oxygen (DO), biochemical oxygen demand (BOD5), chlorophyll-a and total suspended solids (TSS) were studied. The results showed that the water was warmer at 0.5 m depth. As the depth increased, temperature in the reservoir decreased in the range of 4.40°C to 7.35°C from 0.5 to 20 m depth. The concentration of DO dropped to zero at 4 - 6 m depth leading to anoxic level. pH at 0.5 m depth ranged from 6.40 to 7.20 and they were significantly higher (p<0.05) than those at 10 and 20 m. Chlorophyll-a at 0.5 m were in the range of 4.61 to 20.50 mg/L, relatively higher compared to 10 m and 20 m depths. The results obtained indicates that impoundment of Murum River generally caused water quality deterioration. In addition, this could be due to anthropogenic activities such as plantation and logging activities that are still going on within the catchment during the impoundment. Therefore, further continuous monitoring and investigation is required to determine the long-term water quality condition and identify factors that influence water quality in Murum Reservoir.
The residual activity of herbicides in soil and water may be detrimental to the environment. This issue has caught the attention of environmentalists and among the herbicides concerned are a mixture of Imazapic and Imazapyr, also known as OnDuty®, which is currently being used in the Clearfield® Production System. These herbicides are widely used to control weedy rice in rice fields. In order to determine their residues in both soil and water, an accurate and simple method of extraction has to be developed. In the present study, extraction processes followed by HPLC-UV separation was developed and validated for simultaneous determination of imazapic and imazapyr in two matrices, namely soil and water. Verification of chemical compounds was then determined by using LC-MS (ToF). Recovery values of imazapic and imazapyr using 10 μM ammonium acetate extraction from blank samples spiked at levels between 1 mg L-1 and 10 mg L-1 in soil and water were 83% to 106% (with RSD ≤9%). The limit of detection (LOD) ranged from 0.25 to 0.46 mg L−1 while the limit of quantification (LOQ) was from 0.74 to 1.37 mg L-1. LC-MS (ToF) mass spectrum analyses of imazapyr and imazapic were obtained at m/z 262.12 with the retention time of 2.39 min and m/z 276.13 with the retention time of 3.06 min, respectively. This method would be helpful in determining the level of pesticides in soil and water in a shorter time (< 6 min).
Tanah runtuh jenis rayapan merupakan salah satu fenomena geobencana yang sering terjadi dalam skala yang besar dan amat berkait rapat dengan perubahan tekanan air liang. Ia bercirikan canggaan jangka masa panjang maka dengan itu pengetahuan mendalam terhadap tindak balas rayapan di dalam keadaan tepu dan tidak tepu air adalah penting untuk meramal pergerakan masa hadapan. Kertas ini bertujuan mengkaji tindak balas rayapan di dalam sampel lempung bebola menggunakan kotak ricih terus yang terubah suai. Simulasi rayapan dibuat menggunakan model analog mekanik hasil gabungan spring dan peredam. Parameter γo (pergerakan rayapan awal) yang diperoleh daripada ujian kotak ricih terubah suai digunakan sebagai input parameter bersama-sama dengan parameter lain yang diperoleh berdasarkan kaedah kuasa dua terkecil. Simulasi oleh model analog mekanik terhadap tindak balas rayapan yang direkod di makmal berjaya merakam tindak balas rayapan awal dan akhir. Keputusan kajian mendapati bahawa tindak balas rayapan adalah lebih signifikan di dalam keadaan tepu air berbanding keadaan tidak tepu air.
In this study, we propose the estimation of the concentration parameter for simultaneous circular functional relationship model. In this case, the variances of the error term are not necessarily equal and the ratio of the concentration parameter λ = is not necessarily 1. The modified Bessel function was expended by using the asymptotic power series and it became a cubic equation of κ. From the cubic equation of κ, the roots were obtained by using the polyroot function in SPlus software. Simulation study was done to study the mean, estimated bias, absolute relative estimated bias, estimated standard error and estimated root mean square error of the estimation of the concentration parameter. From the simulation study, large concentration parameter and sample size show that the estimated concentration parameter has smaller bias. Also, an illustration to a real wind and wave data set is given to show its practical applicability.
In this paper we prove the existence of ϒ-fixed point for a multidimensional nonlinear mappings F : Xk → X defined on the partially ordered metric spaces and satisfying (ψ, θ, ϕ)-weak contractive conditions. Moreover, we prove the uniqueness of that fixed point under extra conditions to (ψ, θ, ϕ)-weak contractive conditions.
Jujukan batuan sedimen Kapur Awal Kumpulan Gagau di kawasan sekitar hulu Sungai Chichir dibentuk oleh batu pasir
berpebel masif, batu lumpur masif dan lapisan tebal batu pasir dengan pelbagai struktur sedimen serta fosil. Jujukan ini
boleh dibahagikan kepada tujuh fasies dengan mekanisme pengenapan berbeza. Berdasarkan asosiasi antara pelbagai
fasies sedimen dapat ditafsirkan bahawa jujukan ini telah terenap dalam pelbagai sekitaran dataran aluvium termasuk
alur sungai utama, sungai berliku, sungai berburai dan dataran banjir. Fosil yang ditemui memberikan usia Kapur
Awal kepada jujukan ini. Bukti kehadiran tanah atas di kawasan ini mencerahkan harapan untuk penemuan pelbagai
fosil hidupan daratan, khususnya fauna vertebrat serta dinosaur yang lebih baik dan lengkap.
The study was conducted to determine the best model suitable for the determination of ferrum uptake in Brassica chinensis (flowering white cabbage). A nonlinear regression model was selected to determine the amount of ferrum absorbed by each part of the Brassica chinensis plant namely the leaves, stems and roots. The Levenberg-Marquardt method was used to perform the nonlinear least square fit. This method employs information on the gradients and hence requires specification of the partial derivatives. A suitable model was obtained from the exponential regression model. The polynomial model was found to be appropriate for leaves, the mono-exponential model was suitable for stems and the simple exponential model for roots. The residual plots and the normal probability plots from each of the models indicated no substantial diagnostic problems, so it can be concluded that the polynomial and exponential regression models provide adequate fit to determine data on heavy metal uptake by the flowering white cabbage.
The present study was conducted to evaluate the potential of green water meal (GWM) as an alternative dietary ingredient
for juvenile Pacific white shrimp, Litopenaeus vannamei. Five isoproteic and isolipidic diets were formulated with 0%
(GWM0, control diet), 10% (GWM10), 20% (GWM20), 30% (GWM30) and 40% (GWM40) of GWM replacing fishmeal protein
and fed five times daily to triplicate groups of shrimp with an average initial weight of 6.42±0.02 g. In general, growth
performance and feed utilization of shrimp fed with GWM10 did not show any significant differences with the control
diet. Survival rate was above 88% and not affected by the dietary treatments. The whole-body protein and lipid of the
shrimps decreased with the increasing GWM level in the diets. The shrimps fed with the GWM-based diets (GWM10, GWM20,
GWM30 and GWM40) presented more intense red/orange colour and contained higher total carotenoid concentration
compare with the control diet. The present findings suggested that GWM is an excellent source of carotenoid for shrimp
pigmentation and able to replace fishmeal protein at up to 10% replacement level.
The yellowtail scad, Atule mate, forms important fisheries throughout the Indo-Pacific region. To know about the stock status of A. mate in Malaysia, various population parameters were measured, by utilizing length-frequency data, that included asymptotic length (L∞), growth coefficient (K), mortality rates (Z, F and M), exploitation level (E) and recruitment pattern of this species from Marudu Bay, Sabah, Malaysia. Total length and body weight relationship was estimated as W = 0.007TL3.148 (R2 = 0.937). The asymptotic length (L∞) and growth coefficient (K) were estimated 27.80 cm and 1.50 yr−1, respectively. Total mortality (Z), natural mortality (M) and fishing mortality (F) were found to be 4.53, 2.46 and 2.07 yr−1, respectively. The exploitation level (E) was estimated 0.46. It was showed that the recruitment pattern was continuous with two major peaks per year. Relative yield per recruit predicted a maximum exploitation rate (Emax) which was 0.55. The current E value (0.46) is lower than the optimum exploitation (E = 0.50) as well predicted Emax. Therefore, it could be concluded that stock of A. mate in the investigated area of Marudu Bay, Sabah is under exploited.
Population genetic structure of Varuna litterata living along the coast of Thailand were examined in this study. The samples were collected from 3 coastal regions: The Andaman sea (Satun, Trang, Phang Nga), the lower Gulf of Thailand (Pattani, Songkhla, Nakhon Si Thammarat) and the upper Gulf of Thailand (Petchburi, Samut Songkram, Rayong, Trat). Intraspecific variation was determined based on partial sequences of the cytochrome oxidase subunits I gene. A total of 182 samples were collected but only 32 haplotypes were obtained from these samples. An excess of rare haplotypes indicated that the female effective population size of V. litterata living along the coast of Thailand is large. Estimated values of haplotype diversity and nucleotide diversity were 0.790 and 0.003, respectively. The AMOVA (analysis of molecular variance) and phylogenetic analysis results showed that based on genetic variation, the population of this organism was found to have 2 genetically different populations: The Andaman sea population and the Gulf of Thailand population. Genetic exchange of V. litterata among populations inhabiting along the coast of Thailand could be described by the stepping stone model. The results of neutrality tests, both Tajima's D and Fu's Fs statistics, yielded negative values (-1.992 and -26.877, respectively) and statistically significant deviation from the neutrality, indicating that the V. litterata living along the Thailand coast had experienced population expansion. Mismatch distribution analysis indicated that a possible expansion occurred 211,428 years ago during the Pleistocene glaciations period.
MeSH terms: Electron Transport Complex IV; Female; Genetics, Population; Haplotypes; Nucleotides; Phylogeny; Population Density; Thailand; Genetic Variation; Chromosome Structures
The benefits of using structural lightweight concrete in construction industry, particularly in high rise buildings, over normal weight concrete are numerous. The main method of producing structural lightweight concrete is the use of lightweight aggregates instead of ordinary aggregates in concrete. Due to the limited resources for natural and artificial lightweight aggregates, the alternative sources for lightweight aggregates should be discovered from industrial wastes. Oil palm shell (OPS) and oil-palm-boiler clinker (OPBC) are two solid wastes from palm oil industry and are available in abundance in tropical regimes. The use of just OPS as coarse lightweight aggregate in concrete mixture has some drawbacks for concrete. The aim of this study was to investigate engineering properties of a lightweight concrete containing both of these aggregates. For this purpose, in this study, 50% (by volume) of OPS was replaced with OPBC in an OPS lightweight concrete. The test results showed that when OPS was substituted with OPBC, significant improvement was observed in the compressive, splitting tensile and flexural strengths. In addition, initial and final water absorption as well as drying shrinkage strain of blended coarse lightweight aggregate concrete were significantly less than OPS concrete.
MeSH terms: Construction Materials; Desiccation; Engineering; Industrial Waste; Water; Physical Phenomena; Construction Industry; Solid Waste
This study aimed to optimize the condition of silica-supported nanoscale zero valent iron (NZVI/SiO2) synthesis by colloidal impregnation method. Box-Behnken design (BBD) was used as a tool to create and analyze the 17 synthesized conditions of NZVI/SiO2 samples. The independent variables included ethanol concentration (0-100 vol%), amount of silica (0.025-0.125 g) and agitation speed (100-400 rpm). In addition, analysis of variance (ANOVA) for a response surface quadratic model was used to approximate statistical relationship of independent variables. The reducing performance of the synthesized NZVI/SiO2 was examined through removal of Cr(VI) contaminated in water. The optimum of NZVI/SiO2 synthesis was validated with 100 vol% of ethanol concentration, 0.075 g of silica amount, and 100 rpm of agitation speed. The materials were characterized using X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), and nitrogen adsorption/desorption which showed the existence of NZVI phase, composition, and morphology. The Cr(VI) removal efficiency of the NZVI/SiO2 was tested further at the solution pH 4, 7 and 10 in comparison with that by pristine NZVI and silica-unsupported NZVI (NZVI + SiO2). Among the three materials, NZVI/SiO2 presented the highest Cr(VI) removal, especially at pH 7 and 10 with 98 and 94.41%, within 60 min. This was due to the adsorption of Cr(OH)3 and Fe(OH)3 precipitates over SiO2 resulting in availibilty of NZVI/SiO2’s active sites. The proposed mechanism of Cr(VI) removal by NZVI/SiO2 was also described.