In this study, natural Hydroxyapatite (HA) was extracted from clean cow bone by treatment with NaOH and heating at high temperature before ground into fine powder. The HA powder were than mixed together with binder for several hours. Dense HA were formed in die steel mould by using uniaxially pressing method. Sample was sintered at different temperature 1150, 1200, 1250 and 1300°C for several hours. The phases of specimen were identified using X-ray diffraction (XRD). The mechanical properties were analyzed using three-point bending testing and the microstructure was observed by scanning electron microscopy. From XRD results, natural HA shows phase of pure HA up to 1250 o C and fracture strength results indicated that the mechanical properties of specimen increase as temperature increase. From microstructure observation using SEM, HA specimen shows initial stages of sintering process at temperature 1150°C and show changes in microstructure evolution as temperature increase up to 1300°C.
Fine grinding of high purity talc in jet mill at low grinding pressure was carried out by varying the feed rate and classifier rotational speed. These ground particles were sonicated in laboratory ultrasonic bath by varying the soniction period at five levels. The ground and sonicated particles were characterized in terms of particle size and particle size distribution. Mechanochemical and sonochemical effect of talc was determine via X-ray diffraction. Particle shape and surface texture of the ground and sonicated product was determined via scanning electron microscope and transmission electron microscope. The ground particle size exhibited particle size below 10 µm with narrow size distribution. The reduction of peak intensity in (002) plane indicated the layered structure has been distorted. The sonicated talc shows that the thickness of the talc particles after the sonication process is 20 nm but the lateral particle size still remains in micron range. The reduction of the XRD peak intensity for (002) plane and thickness of sonicated talc as shown in SEM and TEM micrographs proves that fine grinding and sonication process produces talc nanosheets.
Barium strontium titanate (Ba0.7Sr0.3TiO3) powder was processed at temperature 80 o C by reacting titania sol in aqueous solutions that contained BaCl2, SrCl2 and NaOH at atmospheric pressure.
The structural characteristic of the powder and sintered pellet were studied using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) whereas the electrical characteristic was determined via Impedance Spectroscopy (IS) and LCR meter. The synthesized powder was found to have a tetragonal phase after heating at 1300 o C. XRD pattern also showed the presence of secondary phase BaTi2O5 (BT2). The SEM results shows the fine grain size was in the range of 0.2 Pm to 0.4 Pm whereas the large ones are approximately 0.8 Pm to 1.2 Pm The ac response of sample sintered at 1300 o C indicated that three electrically different regions. Element 1 can be assigned as a ferroelectric grain boundary region and it is actually BT2, element 2 as a ferroelectric bulk region and the third element is a conductive core which has a low resistance (200 :) and capacitance value.
This study aimed to determine total phenolic content (TPC), total antioxidant activity (TAA), antioxidant vitamin composition (A, C, and E) of pomegranate fruit. In addition, two edible parts of pomegranate juice, pomegranate seed, and combination of them were compared based on antioxidant properties. TPC was determined by using Folin-Ciocalteu (FC) method based on colorimetric reduction. Ferric reduction ability power (FRAP assay) was used to test the antioxidant activity. Vitamin assessments were conducted by using high performance liquid chromatography (HPLC). Results for antioxidant vitamin composition in pomegranate juice (PJ) showed that the concentration of vitamin A was 22.8 ± 0.69 μg/100 g, vitamin C was 57.8 ± 0.59 mg/100 g, and vitamin E was 0.07 ± 0.01 mg/100 g. Besides, TPC in PJ, pomegranate seed (PS), and pomegranate seed-juice (PSJ) was 2502 ± 54, 165 ± 49, and 2696 ± 49 mg GAE/L, and TAA was 32 ± 5.1, 20 ± 2.8, and 47 ± 5.5 mmol/L respectively. This study revealed that PSJ contained high level of phenolic compounds, antioxidant activity, and vitamin C. In addition, TPC was as main contributor to antioxidant activities, and positively correlated with TAA (r2 = 0.91, p
Matched MeSH terms: Chromatography, High Pressure Liquid
This study was conducted to determine the cholesterol and alpha-tocopherol contents of 20 marine fish and four other seafood from the Straits of Malacca. Cholesterol and alphatocopherol contents of the fish and other seafood were determined using high-performance liquid chromatography. The results showed that most of the fish contained low amounts of cholesterol, except sixbar grouper (Epinephelus fasciatus), long-tailed butterfly ray (Gymnura sp.), yellowstripe scad (Selaroides leptolepis), cuttlefish (Sepia officinalis), large-scale tongue sole (Cynoglossus arel), and longtail shad (Hilsa macrura) that contained high amounts of cholesterol (119.39-353.97 mg/100 g wet samples). Indian mackerel (Rastrelliger kanagurta), giant seaperch (Lates calcarifer), prawn (Metapenaeus affinis), and moonfish (Trachinotus blochii) had high alpha-tocopherol contents (462-989 μg/100 g wet sample). Regular consumption of fish and other seafood is highly recommended partly due to the high alphatocopherol content. Due to the high cholesterol in certain types of fish, consumption of the fish fillets of sixbar grouper, long-tailed butterfly ray, yellowstripe scad, cuttlefish, and large scale tongue sole should be < 100 g per day and < 50 per day for longtail shad. Validation of the analytical method also showed a high accuracy and reproducibility of the HPLC method.
Matched MeSH terms: Chromatography, High Pressure Liquid
The effect of chamber pressure of a freeze dryer on essential oil contents, drying kinetics, drying characteristics lemon balm leaves and morphology of lemon balm glandular trichomes (oil reservoirs) were investigated. It was found that overall freeze drying (FD) carried out at high (FD-HP) and low pressure (FD-LP) settings consist of sublimation rate, first falling rate and second falling rate periods. Drying rate of FD-LP dried Lemon Balm leaves are higher than FD-HP dried samples, where the drying rates ranged from 0.063 to 0.449 g H2O/ g DM. s and 0.0365 to 0.395 g H2O/ g DM. s, respectively. 3rd order Polynomial model was found to be the best fit model for both drying kinetics. In terms of product quality, eight (8) major constituents of lemon balm leaves essential oil were quantified. Further to this, electro-microscope was used to observe the peltate glandular hairs structure. Product quality analysis showed that FD-HP retained higher amount of essential oil, shape of glandular hairs, but no positive effect on the freeze drying duration.
Bioactive compounds from Quercus Infectoria (manjakani) were extracted with six different types of solvents: 100% methanol, ethanol, acetone, aqueous and 70% methanol and ethanol. High Performance liquid chromatography (HPLC) was used to identify and quantify the active compounds, namely gallic acid and tannic acid. Total phenolics content were determined by Folin-Ciocalteu while antioxidant and antibacterial activity were tested using DPPH free radicals scavenging and disc diffusion assay. The result revealed that aqueous extract contained the highest concentration of bioactive compounds compared to other types of solvents which are 51.14 mg/g sample and 1332.88 mg/g sample of gallic acid and tannic acid respectively.. The highest level of phenolic compound was found in 100% acetone extract (121 mg GAE/g). The results demonstrated that aqueous extract gives the highest antioxidant activity approximately 94.55% while acetone extract gives the largest inhibition zone for disc diffusion assay which is 19.00 mm respectively. The results revealed rich sources of gallic acid and tannic acid in Q. infectoria which might provide a novel source of these natural antioxidant and antibacterial activity.
Matched MeSH terms: Chromatography, High Pressure Liquid
A study was carried out to compare the composition and thermal profiles of the fat component of six brands of commercial biscuits (BA, BB, BC, BD, BE & BF) with those of lard and palm oil. Extraction of fat from biscuit samples was done using petroleum ether according to the soxhlet extraction procedure. The isolated fat samples along with lard and palm oil were analyzed using gas liquid chromatography (GLC), reversed-phase high performance liquid chromatography (RP-HPLC), and differential scanning calorimetry (DSC). According to GLC analysis, palm oil, lard and all six biscuit brands had either palmitic or oleic acid as major fatty acids. Sn-2 positional analysis of fatty acids showed that oleic (> 60%) as the most dominant fatty acid of palm oil and biscuit brands BA, BB, BC, and BD while palmitic (> 60%) as the most dominant fatty acid of lard and biscuit brands BE and BF. RP-HPLC analysis showed that the triacylglycerol (TAG) profiles of lard and biscuit brands BE and BF were closely similar while those of brands BA, BB, BC, and BD and palm oil were similar. DSC analysis showed that the cooling and heating profiles of lard and brands BE and BF were similar, while those of palm oil and brands BA, BB, BC, and BD were similar. Hence, this study concluded that biscuit brands BE and BF are not suitable for consumers whose religious restriction prohibit the use of lard as food ingredient.
Matched MeSH terms: Chromatography, High Pressure Liquid
Thalassaemia screening programme has been conducted in Malaysia since 2004. The aim of the programme was to reduce the burden of the disease by identifying thalassaemia carriers. However, the response towards the screening activities was unsatisfactory as there was lack of public awareness against the importance of thalassaemia screening. An alternative approach is to screen blood donors. The purpose of this study was to observe the prevalence of thalassaemia carriers among healthy blood donors. Seven hundred and thirty eight healthy blood donors were screened in Hospital Tengku Ampuan Rahimah, Klang from July to September 2010 using cation-exchange high performance liquid chromatography (HPLC). Cases with haemoglobin variants were further analyzed by gel electrophoresis at alkaline pH. Result shows that the blood donors consisted of 413 Malays (56%), 162 Indians (22%), 148 Chinese (20%) and 15 others (2%). There were 19 (2.6%) individuals with haemoglobin E trait, six (0.8%) with co-inheritance of haemoglobin E and αα- thalassaemia and five (0.7%) with β-thalassaemia trait. Haemoglobin Constant Spring and haemoglobin A2 prime were observed in two (0.3%); and Haemoglobin Lepore and alpha chain variant in one (0.2%). αα-thalassaemia and normal haemoglobin A2 β-thalassaemia could not be excluded in 190 cases (26%), as they required deoxyribonucleic acid (DNA) studies for identification. Thalassaemia screening in blood donors is more feasible and effective. Therefore, a wider scale population screening including blood donors could benefit the existing thalassaemia screening programme in Malaysia.
Matched MeSH terms: Chromatography, High Pressure Liquid
Subdermal etonogestrel implant (Implanon®) is the newest, long term contraceptive implant which has recently been made available to Malaysian women. This prospective study was conducted to determine the effects on selected health indices among 42 women who had consented to Implanon® as their choice of contraception. Health indices were checked prior to Implanon® insertion and six months post insertion. Findings indicate a significant reduction in total cholesterol with a significant increase in total haemoglobin and BMI. However there was no significant change noted in the fasting blood sugar, glycosylated haemoglobin, systolic blood pressure and diastolic blood pressure.
Introduction: Thalassaemia is an inherited blood disorder and is a significant public health alarm in Malaysia with many not knowing they are carriers of this haemoglobin disorders. Materials and methods: This study conducted a one off collection of blood samples from 72 Malays students of International Islamic University Malaysia (IIUM) in Kuantan. Blood samples were subjected to conventional haemoglobin analyses that include full blood count and picture, HPLC, Haemoglobin electrophoresis and H-inclusion test. All samples were also genotyped for alpha thalassaemia–1 of Southeast Asia (a-Thal1SEA). Result: There were 17(23.6%) students who were diagnosed as thalassaemia carriers. Out of this, four (5.5 %) and six (8.3 %) students were presumptive β-thalassaemia trait and Haemoglobin-E trait as determined by the HPLC assay respectively. Nine (12.5%) students were genotyped a-Thal1SEA among whom two were also β-thalassaemia carriers. All thalassaemia cases had MCH of < 27pg. Nonetheless, two out of six Haemoglobin-E trait and three out of nine a-Thal1SEA carrier had MCV value of >80fL. Two out of four (50%) presumptive β -thalassaemia trait and one out of six (17%) students of presumptive Haemoglobin-E trait had family history of thalassaemia respectively. Conclusion: The high occurrence of the three common types of thalassaemia carrier (β, Hb-E and a-Thal1SEA thalassaemia) in our small group of subjects could be due to better participation of students who had family history of thalassaemia. The study reaffirmed the importance of molecular study for detection of alpha-thalassaemia and the use of MCH value of
Matched MeSH terms: Chromatography, High Pressure Liquid
Abnormalities in endothelial cell structure and function may lead to diseases such as thrombosis and atherosclerosis. Oxidative stress plays an important role in the pathogenesis of various cardiovascular diseases including atherosclerosis. Previous studies have shown a relationship between a diet rich in flavonoid and a reduced incidence of cardiovascular diseases. Piper sarmentosum (PS) is a plant with high flavonoid content and it possesses antioxidant and anti-atherosclerotic activities. Therefore this study aimed to investigate the flavonoids present in aqueous extract of PS (AEPS) and its cytoprotective effects in oxidative stress-induced human umbilical vein endothelial cells (HUVEC). AEPS contained high total phenolic content (91.02 ± 0.02 mg QE/g DM) and total flavonoid content (48.57 ± 0.03 mg GAE/g DM). Screening using high performance liquid chromatography (HPLC) technique showed the presence of rutin and vitexin as the main flavonoids in AEPS. HUVEC were exposed to 180 µM H2O2 and treated with various concentrations of rutin or vitexin (10 to 400 µM) for 24 hours. Both rutin and vitexin at the concentration of 150-400 µM significantly increased the viability of H2O2-induced HUVEC as denoted by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Therefore rutin and vitexin as the main flavonoids present in PS may be involved in the protective effects of PS against oxidative stress.
Matched MeSH terms: Chromatography, High Pressure Liquid
Magnetic nanoparticles of Fe₃O₄ were synthesized and characterized using transmission electron microscopy and X-ray diffraction. The Fe₃O₄ nanoparticles were found to have an average diameter of 5.48 ±1.37 nm. An electrochemical biosensor based on immobilized alkaline phosphatase (ALP) and Fe₃O₄ nanoparticles was studied. The amperometric biosensor was based on the reaction of ALP with the substrate ascorbic acid 2-phosphate (AA2P). The incorporation of the Fe₃O₄ nanoparticles together with ALP into a sol gel/chitosan biosensor membrane has led to the enhancement of the biosensor response, with an improved linear response range to the substrate AA2P (5-120 μM) and increased sensitivity. Using the inhibition property of the ALP, the biosensor was applied to the determination of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). The use of Fe₃O₄ nanoparticles gives a two-fold improvement in the sensitivity towards 2,4-D, with a linear response range of 0.5-30 μgL-1. Exposure of the biosensor to other toxicants such as heavy metals demonstrated only slight interference from metals such as Hg2+, Cu2+, Ag2+ and Pb2+. The biosensor was shown to be useful for the determination of the herbicide 2, 4-D because good recovery of 95-100 percent was obtained, even though the analysis was performed in water samples with a complex matrix. Furthermore, the results from the analysis of 2,4-D in water samples using the biosensor correlated well with a HPLC method.
Matched MeSH terms: Chromatography, High Pressure Liquid
Bee pollen is considered as one of the functional foods due to its complex biochemical
properties. Bee pollen which is collected from pollen grains from various botanical sources
contains almost a complete nutrition such as carbohydrates, proteins, amino acids, vitamins
and minerals. Its beneficial effect on health is thought to be due to the presence of phenolic
compounds with its antioxidant activity. Antioxidant activities of ethanolic bee pollen extract
(BPE) from three species of Malaysian stingless bee; Trigona thoracica, Trigona itama and
Trigona apicalis in this study were measured using DPPH-HPLC method and gallic acid (GA)
as a standard reference. The percentage of DPPH inhibition by T. apicalis BPE at 1 mg/mL
showed the highest inhibition (39%, GA equivalent to 0.3 mg/mL) compared with T. itama
(14.3%, GA equivalent to 0.1 mg/mL) and T. thoracica (6.7%, GA equivalent to 0.05 mg/mL).
Our result was the first in reporting antioxidant activity of BPE measured using DPPH-HPLC
method from three different species of Malaysian stingless bee.
Matched MeSH terms: Chromatography, High Pressure Liquid
Vitamin E is recognized as an essential vitamin since its discovery in 1922. Most vegetable oils contain a mixture of tocopherols and tocotrienols in the vitamin E composition. Structurally, tocopherols and tocotrienols share a similar chromanol ring and a side chain at the C-2 position. Owing to the three chiral centers in tocopherols, they can appear as eight different stereoisomers. Plant sources of tocopherol are naturally occurring in the form of RRR while synthetic tocopherols are usually in the form of all-racemic mixture. Similarly, with only one chiral center, natural tocotrienols occur as the R-isoform. In this review, we aim to discuss a few chromatographic methods that had been used to separate the stereoisomers of tocopherols and tocotrienols. These methods include high performance liquid chromatography, gas chromatography and combination of both. The review will focus on method development including selection of chiral columns, detection method and choice of elution solvent in the context of separation efficiency, resolution and chiral purity. The applications for separation of enantiomers in vitamin E will also be discussed especially in terms of the distinctive biological potency among the stereoisoforms.
Matched MeSH terms: Chromatography, High Pressure Liquid
Throughout the cryopreservation process, plants were exposed to a series of
abiotic stresses such as desiccation and osmotic pressure due to highly concentrated
vitrification solution. Abiotic stress stimulates the production of reactive oxygen species
(ROS) which include hydrogen peroxide, superoxide radicals, and singlet oxygen. Higher
production of ROS may lead to oxidative stress which contributes to the major injuries in
cryopreserved explants. Antioxidant enzymes in plant such as ascorbate peroxidase
(APX) can protect plants from cell damage by scavenging the free radicals. This study was
determined based on APX enzyme activity of Aranda Broga Blue orchid’s protocorm-like
bodies (PLBs) in response to PVS2 (Plant Vitrification Solution 2) cryopreservation
treatments at different stages. PLBs that were precultured at 0.25 M sucrose for 3 days
were subjected to vitrification cryopreservation method. Results obtained showed that the
highest APX activity was achieved at PVS2 cryoprotectant treatment prior liquid nitrogen
(LN) storage. This phenomenon indicating that accumulation of osmotic and dehydrating
stress throughout the cryopreservation treatment resulted in oxidative burst which in turn
leads to higher APX activity in order to control the excess production of ROS. To
conclude, PVS2 treatment was revealed as the most detrimental step throughout
cryopreservation treatment. Thus, this research also suggested that exogenous
antioxidant such as ascorbic acid can be added throughout cryopreservation procedure
especially at PVS2 treatment in the future experiments to aid in regrowth of cryopreserved
explants by reducing oxidative stress.
Beta-thalassaemia is characterized by a decrease (β(+)) or absence (β(0)) in the synthesis of β-globin chains of human haemoglobin. The heterozygous state for β(+) or β(0) result in β-thalassaemia trait in which the hallmark is the presence of an elevated level of Haemoglobin (Hb) A(2) (α(2)δ(2)). In the past, the traditional methods such as cellulose acetate electrophoresis with elution and microcolumn chromatrography have been the techniques used by the majority of the laboratories in Malaysia for the estimation of (Hb) A(2) levels. The recommended method currently is high performance liquid chromatography which has only been introduced in a few laboratories in the country.
Matched MeSH terms: Chromatography, High Pressure Liquid
Quantitative structure-retention relationship(QSRR) method was used to model reversed-phase high-performance liquid chromatography (RP-HPLC) separation of 18 selected amino acids. Retention data for phenylthiocarbamyl (PTC) amino acids derivatives were obtained using gradient elution on ODS column with mobile phase of varying acetonitrile, acetate buffer and containing 0.5 ml/l of triethylamine (TEA). Molecular structure of each amino acid was encoded with 36 calculated molecular descriptors. The correlation between the molecular descriptors and the retention time of the compounds in the calibration set was established using the genetic neural network method. A genetic algorithm (GA) was used to select important molecular descriptors and supervised artificial neural network (ANN) was used to correlate mobile phase composition and selected descriptors with the experimentally derived retention times. Retention time values were used as the network's output and calculated molecular descriptors and mobile phase composition as the inputs. The best model with five input descriptors was chosen, and the significance of the selected descriptors for amino acid separation was examined. Results confirmed the dominant role of the organic modifier in such chromatographic systems in addition to lipophilicity (log P) and molecular size and shape (topological indices) of investigated solutes.
Matched MeSH terms: Chromatography, High Pressure Liquid
In a survey of starch-based foods sampled from retail outlets in Malaysia, fungal colonies were mostly detected in wheat flour (100%), followed by rice flour (74%), glutinous rice grains (72%), ordinary rice grains (60%), glutinous rice flour (48%) and corn flour (26%). All positive samples of ordinary rice and glutinous rice grains had total fungal counts below 10(3) cfu/g sample, while among the positive rice flour, glutinous rice flour and corn flour samples, the highest total fungal count was more than 10(3) but less than 10(4) cfu/g sample respectively. However, in wheat flour samples total fungal count ranged from 10(2) cfu/g sample to slightly more than 10(4) cfu/g sample. Aflatoxigenic colonies were mostly detected in wheat flour (20%), followed by ordinary rice grains (4%), glutinous rice grains (4%) and glutinous rice flour (2%). No aflatoxigenic colonies were isolated from rice flour and corn flour samples. Screening of aflatoxin B1, aflatoxin B2, aflatoxin G1 and aflatoxin G2 using reversed-phase HPLC were carried out on 84 samples of ordinary rice grains and 83 samples of wheat flour. Two point four percent (2.4%) of ordinary rice grains were positive for aflatoxin G1 and 3.6% were positive for aflatoxin G2. All the positive samples were collected from private homes at concentrations ranging from 3.69-77.50 micrograms/kg. One point two percent (1.2%) of wheat flour samples were positive for aflatoxin B1 at a concentration of 25.62 micrograms/kg, 4.8% were positive for aflatoxin B2 at concentrations ranging from 11.25-252.50 micrograms/kg, 3.6% were positive for aflatoxin G1 at concentrations ranging from 25.00-289.38 micrograms/kg and 13.25% were positive for aflatoxin G2 at concentrations ranging from 16.25-436.25 micrograms/kg. Similarly, positive wheat flour samples were mostly collected from private homes.
Matched MeSH terms: Chromatography, High Pressure Liquid