Surface polishing affect the staining of nano-tooth coloured materials. Here we studied the effect of tea and coffee staining
on polished nano-composite resin and nano-ormocers. Eighty-four discs (5 × 2 mm) of Filtek Z350 and Ceram X were
fabricated using acrylic molds and polished with either: (1) Sof-lex (2) Enhance/Pogo (3) control (no polishing-Mylar).
After polishing, the tests materials were immersed in either tea or coffee (n=7), for 48, 96 and 168 h at 37°C. The colour
difference (ΔE) values were assessed with a spectrophotometer (Cecil CE 2021 UV/VIS), the data were analysed using
Kruskal-Wallis Test. The results showed that polishing significantly affected the ΔE values of both materials (p<0.05).
In all groups, Ceram X showed less staining than Filtek Z350. Both Filtek Z350 and Ceram X also reacted differently
in coffee and tea. Significant ΔE values for Filtek Z350 obtained with different polishing techniques exposed to coffee in
ascending order: Sof-lex < Enhance/Pogo < Mylar strip. For Ceram X, significant ΔE values obtained in exposure to
tea in ascending order: Pogo < Mylar < Sof-lex. Mylar caused more staining in Filtek Z350 whilst Sof-Lex caused the
least staining. However, in Ceram X, Enhance/Pogo caused the least staining. In conclusion, Ceram X is more colour
stable than Filtek Z350. It may be suggested to always use the polishing system produced by the same company that
produces the restorative material for better staining resistant.
Phenotypic selection of individuals is the first step in a selective breeding program for elite hybrid seed production. In
this study, a total of 295 Jatropha curcas individuals raised from cuttings representing 21 accessions, collected from eight
different countries were evaluated for growth performance. The evaluation was done at the Biodiesel Research Station
of Universiti Kebangsaan Malaysia, Kuala Pilah from December 2012 to December 2013. Individual plants from each
accession were observed on several agronomic and yield related traits and all the data were recorded periodically.
Performance of each accession was analyzed using Statistical Analysis System (SAS) 9.4. Four traits which were plant
height (PH), number of flowers per inflorescence (NFI), number of female flowers per inflorescence (NFFPI) and hundred
seed weight (HSW) showed significant differences among the accessions after one year of planting. Maximum values for
each trait were 115.5 cm for PH, 6 for number of branches per plant (BPP), 9 for number of inflorescences per plant
(NIPP), 25 for number of fruits per plant (NFPP), 5 for number of fruits per inflorescence (NFPI), 191 for NFI, 10 for
NFFPI, 81.0 g for HSW and 70 for number of seeds per plant (NSPP). Accession number 1 from Thailand showed the best
performance for most traits. A highly significant and positive correlation was found between NFPP and NSPP. Based on
superior trait values for NIPP, NFPP, NFPI, NFI, NFFPI and HSW, five plants from accession UKMJC 01, 04, 05, 13 and 14
have been selected for generating elite intraspecific hybrids.
Concentration of Ra-226 and Ra-228 activities in water and sediment samples were measured using the Liquid Scintillation Counter (LSC) and High Purity Germanium Gamma Spectrometry (HPGe). respectively. Concentrations of Ra-226 activity in sediment samples range from 18.93 Bg/ kg to 236.06 Bq/kg and for Ra-228 activity range from 12.59 Bg/kg to 410.60 Bq/kg. Meanwhile, concentrations of Ra-226 activity obtained in water samples range from 0.064 Bg/L to 0.199 Bq/L. These data indicate, that the distribution of Ra-228 and Ra-226 in the study area were varied from one sampling stations to another and is probably related to the contents of suspended particles.
Penentuan kepekatan aktiviti Ra-226 dan Ra-228 dalam sampel air dan sedimen dilakukan masing-masing dengan Pembilang Sintilasi Cecair (LSC) dan Spektrometri Gamma Germanium Lampau Tulen (HPGe). Kepekatan aktiviti Ra-226 dalam sampel sedimen adalah berjulat dari 18.93 Bg/kg hingga 236.06 Bq/kg dan kepekatan aktiviti Ra-228 berjulat dari 12.59 Bg/kg hingga 410.60 Bq/kg. Kepekatan aktiviti Ra-226 dalam sampel air yang diperolehi pula berjulat dari 0.064 Bg/L hingga 0.199 Bq/L. Ini menunjukkan taburan Ra-228 dan Ra-226 di kawasan kajian adalah berubah mengikut lokasi kajian dan berkemungkinan dipengaruhi oleh sifat kandungan bahan terampai.
The determination technique for U (238U, 235U, 234U) and Th (232Th, 230Th, 228Th) isotopes using alpha spectrometry was developed. The developed technique involved digestion, dissolution, coprecipitation, solvent extraction and electrodeposition methods. The NBS River Sediment and Rocky Flats Soil Standard Reference Materials were analysed to determine the accuracy of the technique. A good accuracy and high percentage recovery of the carrier (70 - 90%) indicated that the developed technique was suitable for U and Th isotopes determination. The technique was used to determine the U and Th concentration in monazite, xenotime and zircon samples. The results showed that the U and Th total concentrations were in the range of 21.03 to 171.25 Bq/g and 27.48 to 242.87 Bq/g respectively.
Kaedah penguraian, pemelarutan, pemendakan bersama, ekstraksi pelarut dan pemendapan elektrik telah dikaji dan digunakan untuk mendapatkan suatu teknik yang terbaik dalam penentuan isotop uranium 234U, 235U & 238U) dan torium 228Th, 230Th & 232Th) menggunakan sistem spektrometri alfa. Kepekatan isotop U dan Th dalam bahan rujukan piawai River Sediment dan Rocky Flats Soil (NBS) telah dianalisis untuk menentukan kejituan teknik yang dibangunkan. Kajian ini mendapati kepekatan isotop yang diperolehi adalah menghampiri nilai teraku (sijil) dan peratus perolehan semula pembawa yang besar (70-90%). Ini menunjukkan teknik yang dibangunkan sesuai digunakan untuk penentuan isotop uranium dan torium. Seterusnya teknik yang dibangunkan telah digunakan untuk menentukan kandungan uranium dan torium dalam sampel monazit, xenotim dan zirkon tempatan. Kepekatan jumlah isotop uranium yang diperolehi didapati berada dalam julat 21.03 - 171.25 Bq/g manakala kepekatan jumlah isotop torium pula terletak antara 27.48 - 242.87 Bq/g.
Kajian ini dijalankan bagi mengenalpasti kepelbagaian nisbah 234U/238U yang wujud di dalam jumlah pepejal terampai (TSS) pada lapan stesen yang berbeza di Kuala Selangor, Selangor. Prosedur kajian ini melibatkan proses persampelan, pemendakan, resin penukaran anion, pemendakan elektrik dan teknik pengiraaan spektrometer alfa. Nisbah 234U/238U adalah paling tinggi di Stesen 8 (234U/238U = 2.98) dan Stesen 2 (234U/238U = 3.34) pada persampelan pertama. Manakala pada persampelan kedua julat nisbah 234U/238U adalah lebih luas iaitu antara 1.29 (Stesen 4) hingga 11.57 (Stesen 6). Ini disebabkan oleh berlakunya pergerakan 234U bersama-sama mikroorganisme di dalam fasa terampai dan berlaku proses penurunan U(VI) kepada U(IV) yang akan memendakkan uranium daripada air ke dalam sedimen.
Copper phthalocyanine (CuPc) thin films have been prepared using a simple spin coating method. The films were annealed at 5 different temperatures (323, 373, 473, 523 and 573 K) for one hour in air. Optical properties study using the UV-Vis spectrophotometer showed that in the range of wavelength of 300-800 nm, all of the films have identical absorption coefficient patterns and there was no systematic changes with respect to annealing temperature. The film annealed at 373 K showed the highest absorbance while the lowest absorbance was shown by the film annealed at 323 K. The results showed that the optical band gaps depended on the temperature. The film annealed at 373 K has the lowest optical energy gap. Using the five annealed films, solar cell with the configuration of Ag / n-Si / CuPc / Ag were fabricated. Under the 50 W/cm2 light illumination, the current voltage measurements at room temperature were carried out on the device. The device which consists of film annealed at 373 K exhibited the best photovoltaic characteristics. The different annealing temperature also affect the photovoltaic behavior of the devices in a non-systematic way.
The prevalence of chronic kidney disease (CKD) have increased and become one of the major public health concerns
worldwide including Malaysia. Previous studies on CKD generally focused on patients who were already undergoing
dialysis treatment; however, studies investigating the stresses experienced by pre-dialysis CKD patients were limited. This
study aimed to examine the prevalence of psychological distress and their association with the Health Related Quality
of Life (HRQoL) during the different stages of CKD. This cross-sectional study involved 200 pre-dialysis patients from
stages 3 to 5, who were recruited from the Nephrology Clinic at the National University of Malaysia Medical Centre
(UKMMC). The instruments used in this study were the Short Form 36 (measuring HRQoL) and Hospital Anxiety and
Depression Scale (HADS) to measure the psychological distress. The results showed that the prevalence of depression
and anxiety increased proportionally with the CKD stages. The HRQoL sub-component scores declined as the CKD stages
increased except for social functioning. An impaired HRQoL was associated with depression and anxiety in the CKD
patients. The results suggested that it is very important to manage kidney disease at an early stage and that a healthier
lifestyle is adopted.
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.
Penyelidikan ini bertujuan untuk mengkaji tindak balas serabut tandan kosong kelapa sawit (EFBF) melalui kaedah modifikasi kimia dan penghidroksilpropilan menggunakan polietilena glikol (PEG). Peringkat pertama merujuk kepada tindak balas modifikasi kimia menggunakan NaOH dan isopropanol. Peringkat seterusnya adalah penyediaan hidroksilpropil-serabut tandan kosong kelapa sawit (HP-EFBF) menggunakan berat molekul PEG berbeza (6000, 8000 dan 10000). Pencirian yang terlibat dalam kajian ini adalah analisis menggunakan mikroskop elektron imbasan (SEM),
spektroskopi inframerah transformasi Fourier (FTIR), analisis termogravimetri (TGA), penentuan kinetik tenaga pengaktifan (Ea), analisis pembelauan sinar-X (XRD), indeks kehabluran Selulosa (CrI) dan pertambahan berat HP-EFBF. Keputusan SEM menunjukkan morfologi permukaan HP-EFBF mula membengkak dan terdapat pembentukan lubang sepanjang permukaan gentian. Spektrum IR juga menunjukkan getaran OH dalam EFBF tanpa rawatan adalah pada 3402 cm-1 tetapi selepas proses penghidroksilpropilan, getaran OH dalam HP-EFBF (10000, 8000 dan 6000) masing-masing sedikit
teranjak kepada 3392, 3384 dan 3370 cm-1. TGA menunjukkan kestabilan terma HP-EFBF 6000 lebih rendah berbanding HP-EFBF 8000 dan 10000. Selepas modifikasi kimia, tenaga pengaktifan, Ea
meningkat daripada 32.4 kepada 51.9 kJ/moL berbanding EFBF tanpa rawatan iaitu 12.5 kJ/moL. XRD menunjukkan puncak belauan (002) teranjak kepada sudut 2θ yang lebih kecil dan puncak [(101), (10Î)] lenyap selepas proses penghidroksilpropilan. Indeks kehabluran selulosa, CrI menunjukkan kehabluran EFBF tanpa rawatan berkurang daripada 27% kepada 25% selepas modifikasi kimia. Semakin tinggi berat molekul PEG yang digunakan, semakin tinggi pertambahan berat HP-EFBF.
Sistem minigenom telah digunakan untuk mengkaji replikasi dan transkripsi virus RNA tidak bersegmen. Objektif kajian ini adalah untuk membina sistem minigenom bagi virus NDV strain tempatan, AF2240 serta bagi mengkaji mekanisme transkripsi dan replikasi virus ini. Bagi tujuan ini lima plasmid digunakan iaitu pMGNDV, pCITENP, pCITEP, pTriEX-T7, dan pGEML. Kesemua plasmid diekstrak secara berskala besar dan dimendakkan menggunakan polietilina glikol. Hasil ekstrak ini digunakan untuk transfeksi ke dalam sel. Translasi in vitro dilakukan dengan menggunakan pCITENP, pCITEP, dan pTriEX-T7 untuk memastikan kesemua konstruk ini berfungsi. Hasil pemblotan western menunjukkan protein bersaiz ~100 kDa (T7), ~53 kDa (NP), ~53 dan 55 kDa (P) berjaya diekspreskan. Protein CAT diperoleh apabila plasmid yang mengekodkan minigenom NDV ditransfeksi bersama plasmid yang mengekodkan protein nukleokapsid (NP), fosfoprotein (P) dan subunit besar polimerase (L) ke dalam sel BHK-21. Dianggarkan 55 pg protein CAT berjaya diperoleh menggunakan kit CAT ELISA. Hasil pemblotan western turut menunjukkan protein CAT bersaiz 25 kDa dihasilkan. Kesimpulannnya, system minigenom ini berupaya untuk berfungsi dan mampu mengekspreskan gen asing di dalam sel mamalia BHK-21.
Aluminum foams were fabricated by sintering dissolution process (SDP) using sodium chloride (NaCl) as space holder. The compositions of space holder, used in this study were 40 and 60 wt. % with different dissolution times; 1, 2 and 3 h. The effect of different dissolution times on compressive behavior and energy absorption of foams were evaluated. The result showed that by increasing space holder and dissolution times, energy absorption capability increases. For aluminum foam contains 60 wt. % NaCl, longer dissolution times resulted in thinner cell wall and cell structure become more unstable which lead to lower plateau region.
Filem nipis ZnO terdop Ga (ZnO:Ga) disediakan menggunakan teknik sol-gel dan salutan berputar. Ga didopkan kepada ZnO dengan peratusan berat (wt. %) yang berbeza iaitu 0, 2, 4, 6 dan 8 wt. %. Kesan pengedopan Ga ke atas struktur dan sifat optik filem nipis ZnO dikaji. Pencirian struktur filem nipis ini dilakukan menggunakan kaedah pembelauan sinar-X (XRD), mikroskop imbasan elektron pancaran medan (FESEM) dan mikroskop daya atom (AFM). Pencirian sifat optik filem nipis pula dilakukan menggunakan spektroskopi ultraungu cahaya nampak (UV-VIS) dan fotoluminesen (PL). Ujian XRD mengesahkan kesemua sampel berstruktur wurtzit. Saiz kristalit ZnO mengecil dengan peningkatan peratusan berat Ga seterusnya mengurangkan kekasaran permukaan filem. Pengedopan Ga menunjukkan peratus transmisi cahaya pada panjang gelombang 300 - 380 nm bertambah berbanding filem nipis ZnO tanpa dop. Nilai jurang tenaga optik, Eg dan keamatan PL filem nipis ZnO meningkat apabila pengedopan Ga dilakukan. Hasil kajian ini menunjukkan saiz kristalit yang lebih kecil memberi kesan ke atas sifat optik sampel pada peratus pengedopan Ga 0-6%. Pada peratus pengedopan Ga yang lebih tinggi, kesan transformasi struktur menjadi lebih dominan dalam mempengaruhi nilai Eg.
Salted fish is a locally processed raw food which is used in everyday cooking among Malaysians. Previous studies suggested that salted fish intake was a risk of nasopharyngeal cancer. Hence, this study was carried out to evaluate gene mutation effects through the induction of mutagenic effect of aqueous and methanol extracts of salted fish from Balik Pulau, Pulau Pinang, Malaysia. Balik Pulau was chosen for sampling purpose due to its popularity as a commercial centre for local raw fisheries in Malaysia. Evaluation of mutagenic effect was carried out by hprt Gene Mutation Assay towards V79 lung fibroblast cells. It was found that the aqueous and methanol extracts of salted fish were not cytotoxic towards V79 lung fibroblast cells. It was also found that the extracts of salted fish from Balik Pulau were not mutagenic towards hprt gene of V79 lung fibroblast cells as the mutation frequency of the extracts did not exceed 3 times of the value for negative control mutation frequency. In conclusion, both aqueous and methanol extracts of salted fish from Balik Pulau did not have gene mutation effect towards hprt gene in vitro. However, other toxicological profile could be assessed to determine the mechanism of toxicity of salted fish.
Archerfishes Toxotes chatareus (Hamilton 1822) and Toxotes jaculatrix (Pallas 1767) inhabits mangrove estuaries, which are a critically important habitat as a spawning and nursery ground as well as the full life cycle of many fish species. In order to manage and conserve resilience fish species like the archerfish, we need to know some basic parameters about their biology and life history. Our research has focused on understanding the annual condition factors of these two species of archerfishes, as a complimentary to other several biological aspects of this two species that have been published. Our results indicated that, both species are in good conditions as the mean values of condition factors (Fulton condition factor K and Relative condition factor Kn) are greater than values of unity (K, Kn >1). The average K and Kn values of T. chatareus and T. jaculatrix were lowest in November and highest in September, indicates the spawning and recovery condition of the fishes. Condition factors measure overall fish population health that can be used by fisheries biologists and resource managers in proper management of fish resources in Malaysia waters.
The composite polymer electrolytes (CPEs) composed of polyacrylonitrile (PAN) as host polymer, lithium tetraflouroborate
(LiBF4
) as dopant salt, dissoÅlved in the mixture of ethylene carbonate (EC) and dimethyl phthalate (DMP) as plasticizing
solvent, with the addition of silica (SiO2
) as inorganic filler were prepared by the solution casting technique. The CPE films
were prepared by varying the concentrations of SiO2
from 1 to 5 wt. %. The CPE film containing 3 wt. % of SiO2 exhibits
the highest ionic conductivity of 1.36 × 10-2 S cm-1 at room temperature while for temperature dependence studies, the
plot obtained obeyed Arrhenius rule and the calculated activation energy was 0.11 eV. The ionic conductivity of the CPEs
was found to depend on the concentration of ion pairs of dopant salt as showed by FTIR spectra. The calculated value of
lithium ions transport number, tLi+ for the highest conducting CPE film was 0.15. This result indicates that anionic species
are the main contributor to the total conductivity of the CPE. The CPE film has an electrochemical stability higher than
the non-filler film.
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.
Hydraulic fracturing becomes more difficult when confronted with a formation of high fracturing pressure. In such formations, acidizing before the main fracturing treatment provide a method to reduce fracture pressure. The aim of this paper was to investigate the evolution of fracture pressure in a wellbore with acidizing. Five experiments were conducted to study the mechanisms of acid damage on reservoir minerals and cementing materials properties. Consequently, a mathematical model to predict fracture pressure with acidizing has been established and verified by field data. The analysis results showed that it is possible to reduce fracture pressure with decreased rock strength and fracture critical stress intensity factor by means of acid damage. Acid damage destroys the crystal structure of mineral particles, breaks the crystalline layers in cementing materials, increases rock porosity and reduces the rock strength. In addition, as the acid concentration, formation temperature and acid treatment time increased, it was useful to reduce fracture pressure in the wellbore. Using the proposed model, we were able to select the optimal acid damage construction parameters to reduce fracture pressure.
NP-SNP interactions have been recognized to be basically important for understanding genetic causes of complex disease
traits. Logic regression is an effective methods for identifying SNP-SNP interactions associated with risk of complex disease.
However, identifying SNP-SNP interactions are computationally challenging and may take hours, weeks and months to
complete. Although parallel computing is a powerful method to accelerate computing time, it is arduous for users to
apply this method to logic regression analyses of SNP-SNP interactions because it requires advanced programming skills
to correctly partition and distribute data, control and monitor tasks across multi-core CPUs or several computers, and
merge output files. In this paper, we present a novel R-library called SNPInt to automatically speed up analyses of SNP-SNP
interactions of genome-wide association (GWA) studies using parallel computing without the advanced programming skills.
The Crohn’s disease GWA studies dataset from the Wellcome Trust Case Control Consortium (WTCCC) that includes 4,680
individuals with 500,000 SNPs’ genotypes was analyzed using logic regression on a computer cluster to evaluate SNPInt
performance. The results from SNPInt with any number of CPUs are the same as the results from non-parallel approach,
and SNPInt library quite accelerated the logic regression analysis. For instance, with two hundred genes and twenty
permutation rounds, the computing time was continuously decreased from 7.3 days to only 0.9 day when SNPInt applied
eight CPUs. Executing analyses of SNP-SNP interactions using the SNPInt library is an effective way to boost performance,
and simplify the parallelization of analyses of SNP-SNP interactions.
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.
Kajian pengimejan resonans magnet kefungsian (fMRI) subjek tunggal ini mengkaji hubung kait asas antara parameter hemodinamik dengan ketinggian pengaktifan (nilai t) bagi beberapa korteks berkaitan motor. Dalam kajian ini, subjek melakukan empat gaya tepikan jari rentak sendiri iaitu sentuh-perlahan (SP), sentuh-laju (SL), tekan-perlahan (TP) dan tekan-laju (TL) dalam satu imbasan fMRI. Data fMRI dianalisis menggunakan pemetaan statistik berparameter (SPM). Keputusan analisis mendapati otak mengkoordinasi keempat-empat gaya tepikan dengan penglibatan girus presentral (PCG) bilateral, kawasan motor tambahan (SMA), lobus parietal superior (SPL) dan serebelum. SPL didapati menunjukkan anjakan kelateralan akibat peningkatan laju tepikan. Magnitud pengaktifan pada SPL kiri yang lebih rendah berlaku semasa tepikan perlahan manakala tepikan laju memperlihatkan magnitud pengaktifan yang lebih tinggi pada SPL kanan. Plot nilai t melawan peratus perubahan isyarat bagi kesemua kawasan tersebut untuk kesemua gaya tepikan menunjukkan korelasi positif (p< 0.05, ρ= 0.67). Nilai t menunjukkan korelasi positif tak bererti terhadap efikasi neuron (p= 0.08, ρ= 0.40), korelasi positif bererti terhadap pereputan isyarat (p< 0.05, ρ= 0.85) dan masa transit (p< 0.05, ρ= 0.88) serta korelasi negatif bererti terhadap suap balik (p< 0.05, ρ= 0.89). Pemalar kekerasan (α) dan peratus ekstraksi oksigen (Eo) didapati kekal malar untuk kesemua korteks dalam semua cara tepikan. Kajian ini telah mendedahkan maklumat asas berguna mengenai ciri hemodinamik beberapa korteks berkaitan motor yang mengalami pengaktifan.