Displaying publications 861 - 880 of 1919 in total

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  1. Johnson JR, Idris Z, Abdullah JM, Alias A, Haspani MS
    Malays J Med Sci, 2017 Mar;24(1):40-46.
    PMID: 28381928 DOI: 10.21315/mjms2017.24.1.5
    BACKGROUND: Intraventricular haemorrhage (IVH) causes blockage of ventricular conduits leading to hydrocephalus, increased intracranial pressure (ICP), and a reduced level of consciousness. The current standard management of IVH is insertion of an external ventricular drainage (EVD) catheter. However, this procedure addresses only the problems of acute hydrocephalus and raised ICP. Endoscopic washout allows for a more complete removal of the intraventricular clot. This study compared these two types of treatment in terms of shunt dependency and relevant clinical outcomes.

    METHODS: Patients who were 10-80 years old and presented with a Graeb score of more than six were randomised into endoscopic washout and EVD treatment groups. A CT brain was repeated on each patient within 24 hours after surgery, and if a patient's Graeb score was still more than six, a repeat endoscopic washout was performed to clear the remaining clots. All patients were monitored for shunt dependency at two weeks and three months, and clinical outcomes were measured at six months after the procedure.

    RESULTS: A total of 39 patients were recruited; 19 patients were randomised into the endoscopic washout group, and 20 were randomised into the EVD group. However, three patients in the endoscopic group refused that treatment and opted for EVD insertion. Patients treated with endoscopic washout had significantly less drainage dependency at two weeks (P < 0.005) and at three months (P < 0.004) as compared to patients in the external ventricular drainage group. The reduction in Graeb scores was also significantly greater in the endoscopic washout group (P < 0.001). However, the functional outcome at six months measured via a modified Rankin scale score was no different in the two groups of patients. The difference in the functional outcome of the patients was mainly dependent on the initial pathology, with those presenting with a thalamic bleed with IVH showing a poor functional outcome. This parameter was also influenced by the Glasgow Coma Scale (GCS) score on admission, with those patients with a score of 12 or less having a poor functional outcome (MRS 5-6) at three and six months after the surgery.

    CONCLUSIONS: The use of neuroendoscopy in patients with a massive IVH significantly reduced drainage dependency. However, it did not alter the final functional outcome.

    Matched MeSH terms: Intracranial Pressure
  2. Tan, J. A. M. A., George, E., Lim, E. J., Zakaria, Z., Hassan, R., Wee, Y. C., et al.
    MyJurnal
    Objectives: This study aimed to evaluate the UBI MAGIWELTM ζ-GLOBIN ELISA Kit for the presumptive diagnosis of αo-thalassaemia. The ELISA results obtained were confirmed by molecular characterisation of αo-thalassaemia using a Duplex-PCR. Methods: Routine peripheral blood counts and red cell indices were determined in 94 blood samples sent for Hb analysis. Hb subtypes were quantified by high performance liquid chromatography (HPLC) and Hb electrophoresis conducted on agarose gel at pH 8.5. Zeta-globin chain levels were determined using the UBI MAGIWELTM ζ-GLOBIN ELISA Kit. Molecular analysis was performed using a duplex-PCR which simultaneously amplifies
    a normal 136 bp sequence between the ψα−α2-globin genes and a 730 bp Southeast Asian deletion-specific sequence (–SEA) between the ψα2−θ1-globin genes. Results: Using the ELISA assay kit, 20 blood samples were presumptively identified as α-thalassaemia carriers from elevated ζ-globin chains (OD>0.3) while the remaining 74 blood samples showed OD
    Matched MeSH terms: Chromatography, High Pressure Liquid
  3. Lai, S.C., Choy, Y.C.
    MyJurnal
    This was a prospective, randomized, double-blind study comparing the effect of remifentanil and fentanyl on cardiovascular responses from laryngoscopy and tracheal intubation. Forty-four ASA I or II patients aged between 18-65 yrs scheduled for elective surgery under general anaesthesia, were recruited and randomized into two groups. Each patient in Group R received remifentanil of 0.5 mcg/kg bolus over 30 seconds followed by an infusion of 0.25 mcg/kg/min and each patient in Group F received fentanyl of 2 mcg/kg bolus over 30 seconds followed by an infusion of normal saline. Anaesthesia was then induced with propofol, rocuronium and 2% sevoflurane with 100% oxygen. Cardiovascular changes were recorded every minute for 3 minutes after induction and 5 minutes after tracheal intubation. The heart rate remained stable throughout the induction and intubation period in both groups. None of the patients in the remifentanil group develop bradycardia. Systolic blood pressure (SBP) and mean arterial pressure (MAP) were significantly lower in the fentanyl group at the 3rd minute post-induction and 5th minute post- intubation (p < 0.05). Diastolic blood pressure (DBP) in the fentanyl group was significantly lower at the 2nd and 3rd minute post-induction and 4th and 5th minute post-intubation (p < 0.05). The blood pressure remained stable for the remifentanil group throughout the induction and intubation period. Six patients (27.2%) in the fentanyl group and one patient (4.5%) in the remifentanil group experienced hypertension. Three patients (13.7%) from each group experienced hypotensive episodes. In conclusion, remifentanil 0.5 mcg/kg bolus followed by 0.25 mcg/kg/min infusion resulted in SBP, MAP and DBP remained slightly lower than baseline throughout the whole period but still consider stable, as these changes were not statistically significant.
    Matched MeSH terms: Blood Pressure
  4. Ooi, Edwin I.L., Safinaz, M.K., Ropilah, A.R
    MyJurnal
    This was a 28-year-old mentally-challenged girl with underlying congenital Rubella syndrome. She was bilaterally aphakic after congenital cataract surgery. She then developed bilateral aphakic glaucoma and had to undergo multiple glaucoma filtering surgeries. The most recent procedure she had undergone for her left eye was a second Ahmed valve implantation with an overlying sclera patch. Postoperatively, intraocular pressure was well controlled. However, nine months later, slit lamp examination revealed the tube was adherent to the overlying cornea with surrounding deep and superficial cornea vascularization. Siedel test was negative and intraocular pressure was normal. Subsequently the tube was removed but the plate was left in situ.
    Matched MeSH terms: Intraocular Pressure
  5. Nadia, M.N., Samsul Johari, M.A., Muhammad, M., Raha, A.R., Nurlia, Y.
    MyJurnal
    This study aimed to compare dexmedetomidine and propofol, in terms of haemodynamic parameters, respiratory rates and offset times, when used for sedation in patients undergoing elective orthopaedic and surgical procedures under regional anaesthesia. This was a prospective, randomised, single-blind study where 88 patients were recruited. Patients were randomised into two groups to receive either dexmedetomidine or propofol infusion. Central neuraxial blockade (spinal, epidural or combined spinal epidural) was performed. After ensuring an adequate block and stable haemodynamic parameters, dexmedetomidine was infused 15 minutes later at 0.4 μg/kg/hr, and propofol, at a target concentration of 2.5 μg/ml. Both drugs were titrated to achieve a bispectral index score of 70 before surgery commenced. Sedation level was monitored using the bispectral index score and assessed by the Observer Assessment of Alertness Scale score. Drug infusion was adjusted to maintain bispectral index scores ranging between 70-80 during surgery. Both groups showed reductions in mean arterial pressure and heart rate from baseline readings throughout the infusion time. However there was no significant reduction in the first 15 minutes from baseline (p > 0.05). Haemodynamic parameters and respiratory rate between both groups were not significantly different (p > 0.05). No patient demonstrated significant respiratory depression or SpO2 ≤ 95%. Offset times were also not significantly different between both groups (p = 0.594). There were no significant differences in haemodynamic parameters, respiratory rates and offset times between dexmedetomidine and propofol used for sedation in patients undergoing elective orthopaedic and surgical procedures under regional anaesthesia.
    Matched MeSH terms: Arterial Pressure
  6. Haizul, I.M., Umi Kalthum, M.N., Mae-Lynn, C.B., Faridah, H.A.
    MyJurnal
    A 50-year-old Chinese man presented with sudden onset of painful right eye, diplopia, and redness associated with headache and deteriorating vision. Examination revealed obvious proptosis with elevated intraocular pressure. Computed tomography (CT) scan showed presence of retrobulbar haemmorhage. Emergency lateral canthotomy and cantholysis was performed followed by medical orbital decompression, resulting in improvements in visual acuity, and other ocular symptoms. The diagnosis of thrombosed orbital varices involving inferior ophthalmic vein was confirmed on radiological- angiographic study. To date, he is symptoms-free with good visual acuity. Immediate surgical decompression with lateral cantholysis for retrobulbar haemorrhage was effective in the treatment of retrobulbar haemorrhage.
    Matched MeSH terms: Intraocular Pressure
  7. Al-Shaham, Ali Abbas Hadi, Al-Shaham, Serene Ali, Jerjess, Mustafa
    Medical Health Reviews, 2009;2009(1):3-13.
    MyJurnal
    Negative pressure if applied in topical manner to a wound surface has been reported to enhance wound healing due to increase in local blood flow, reduction of tissue oedema, and by stimulating angiogenesis. An air-tight film covering the wound is connected by suction tube to a control unit by which negative pressure is applied to the surface of the wound in the range of 80-125 mm Hg. This method has been called negative pressure wound therapy (NPWT) or vacuum assisted closure (VAC). It has been recommended for virtually all kinds of complex wounds. The duration of the therapy varies from several days to several months. This technology promotes formation of granulation tissue, enhances healing of diabetic foot, and significantly reduces the size of the acute and chronic wounds and ulcers. It lowers the morbidity of Fournier’s gangrene, ensures better healing of lower limb wounds and ulcer of ischemic origin, and can serve as temporary wound cover when no closure technique is available. The limitations to using NPWT are presence of dead tissue, exposed vital structures, untreated osteomyelitis, unexplored fistulae and malignant wounds. The cost of the equipment may constitute another factor in limiting the use of this new technology. In conclusion the NPWT under certain circumstances is more effective than other available local wound treatments.
    Matched MeSH terms: Negative-Pressure Wound Therapy
  8. Azhany Y, Hemalatha C, Nani D, Rosediani M, Liza-Sharmini A
    Malays Fam Physician, 2013;8(1):33-7.
    PMID: 25606266 MyJurnal
    Cataract is the most common cause of blindness in the world. An attack of phacolytic and phacomorphic glaucoma as a result of neglected cataract constitutes a medical emergency that must be addressed immediately. Ocular emergencies such as these is challenging for the surgeon with guarded or poor prognosis. We describe the presentation, management and prognosis of three cases of phacomorphic and phacolytic glaucoma. All three patients underwent aggressive management of intraocular pressure. Despite successful cataract operation with implantation of intraocular lens, there was only mild improvement of the vision. Optic nerve and pupil functions were permanently affected following the insult. Phacomorphic and phacolytic glaucoma present a very challenging problem to the surgeon with poor visual outcome. Public health education and awareness are important and health workers should encourage patients with cataract to seek early treatment for better prognosis.
    Matched MeSH terms: Intraocular Pressure
  9. Azizah, A.H., Wee, K.C., Azizah, O., Azizah, M.
    MyJurnal
    Effect of various cooking methods on antioxidant content and radical scavenging activity of pumpkin was evaluated. Pumpkin (Cucurbita moschata) was boiled and stir-fried for 2, 4 and 6 minutes respectively. Beta-carotene and lycopene were determined using HPLC and total phenolics measured using Folin-Ciocalteu method. The free radical scavenging activity of the samples was determined using 1, 1-diphenyl-2 picrylhydrazyl assay. Interestingly, result of the study showed an increase in both beta-carotene (2 to 4 times) and lycopene (17 to 40 times) content of pumpkin after cooking for 2, 4 and 6 minutes. However, the treatment resulted in 18 to 54% losses of total phenolics content of the pumpkin. Nevertheless, the free radical scavenging activity exhibited by cooked pumpkins was found to be high, in the range of 81.1% to 94.6% with IC50 of 1.41 to 1.62 mg ml-1
    .
    Matched MeSH terms: Chromatography, High Pressure Liquid
  10. Cheong, C.K., Hajeb, P., Jinap, S., Ismail-Fitry, M.R.
    MyJurnal
    Sulfonamides (SAs), synthetic antibiotics, are commonly used by veterinarians in chicken for therapeutic, prophylactic or as growth promoter and halt the growth of bacteria in animal production. Four common SAs, Sulfadiazine (SDZ), Sulfamethazine (SMZ), Sulfamethoxazole (SMX) and Sulfaquinoxaline (SQX), were determined in chicken breast and liver samples using reverse phase HPLC using UV detector at 266nm. The concentration of SAs detected in samples from 11 states in Peninsular Malaysia ranged from 0.006-0.062 µg/g in breast meat samples and 0.08-0.193 µg/g in liver samples. Except for sample from Johor, concentration of SAs in all the samples were lower than MRLs established by Malaysia (0.1 µg/g). Exposure of sulfonamides in Malaysian consumers ranged from 0.002-0.088 µg/kg body wt. /day. The highest value of sulfonamides exposure was found in Johor with an estimated daily intake (EDA) of Sulfamethoxazole (SMX) in Johor.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  11. Goh, L.P., Loh, S.P., Fatimah, M.Y., Perumal, K.
    Malays J Nutr, 2009;15(1):77-86.
    MyJurnal
    Microalgae can produce various natural products such as pigments, enzymes, unique fatty acids and vitamin that benefit humans. The objective of the study is to study the bioaccessibility of carotenoids (β-carotene and lycopene) and vitamin E (α- and β-tocopherol) of Nannochloropsis oculata and Chaetoceros calcitrans. Analyses were carried out for both the powdered forms of N. oculata and C. calcitrans, and the dried extract forms of N. oculata and C. calcitrans. In vitro digestion method together with RP-HPLC was used to determine the bioaccessibility of carotenoids and vitamin E for both forms of microalgae. Powdered form of N. oculata had the highest bioaccessibility of β-carotene (28.0 ± 0.6 g kg-1), followed by dried extract N. oculata (21.5 ± 1.1 g kg-1), dried extract C. calcitrans (16.9 ± 0.1 g kg-1), and powdered C. calcitrans (15.6 ± 0.1 g kg-1). For lycopene, dried extract of N. oculata had the highest bioaccessibility of lycopene (42.6 ± 1.1 g kg-1), followed by dried extract C. calcitrans (41.9 ± 0.6 g kg-1), powdered C. calcitrans (39.7 ± 0.1 g kg-1) and powdered N. oculata (32.6 ± 0.7 g kg-1). Dried extract C. calcitrans had the highest bioaccessibility of α-tocopherol (72.1 ± 1.2 g kg-1). However, β-tocopherol was not detected in both dried extract and powdered form of C. calcitrans. In conclusion, all samples in their dried extract forms were found to have significantly higher bioaccessibilities than their powdered forms. This may be due to the disruption of the food matrix contributing to a higher bioaccessibility of nutrients shown by the dried extract forms.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  12. Khoo, H.E., Chong, E.L., Sia, C.M., Chang, S.K., Yim, H.S.
    Malays J Nutr, 2014;20(1):101-111.
    MyJurnal
    Introduction: Hygrocybe conica (HC), a wild mushroom commonly consumed by the indigenous people (Orang Asli) in Peninsular Malaysia, was assessed for its antioxidant content. Methods: The HC mushroom was extracted using distilled water and the crude extract partitioned using different solvents and open column chromatography to evaluate its potential antioxidant properties. The mushroom extract was partitioned using liquid-liquid extraction into the hexane (Fl), chloroform (F2), butanol (F3) and formic acid (F4) fractions. Based on solvent polarity, the water extract of the mushroom was fractionated into non-polar (FI), semi-polar (Fii), and polar fractions (Fiii) using open column chromato­ graphy. Antioxidant capacities were determined using DPPH, ABTS, and ferric reducing antioxidant power (FRAP) assays while Folin-Ciocalteu reagent assay was used to determine total phenolic content (TPC). Results: The HC extract had the highest TPC and DPPH scavenging capacity compared to its extract fractions. TE values (ABTS assay) of F2 and F4 were not significantly higher than the HC extract. Among the extract fractions of different polarities, Fiii had the highest antioxidant capacities (DPPH and FRAP) compared to FI and Fii while FRAP values of these fractions were not significantly lower than the FRAP value of HC extract. The HC extract had significantly lower antioxidant capacity than antioxidant standards (ascorbic acid and BHA). Tannie acid as the main bioactive component in HC mushroom was detected using HPLC method. The presence of phenolics in HC extract was also confirmed using TLC. Conclusion: Due to the presence of potent phenolic components, the mycelia of HC could be consumed for potential antioxidative benefits.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  13. Rashidah, A., Yeo, P.S., Noor Ani, A., Muhammad Fadhli, M.Y., Tahir, A., Feisul Idzwan, M., et al.
    Malays J Nutr, 2014;20(3):317-326.
    MyJurnal
    Introduction: High sodium consumption over an extended period of time has been associated with hypertension, stroke, cardiovascular disease, renal damage, and other adverse health effects. This study aimed to determine urinary sodium excretion and consequently estimate dietary sodium consumption among normotensive health staff in Malaysia. Methods: A cross-sectional study was conducted to acquire data on sodium excretion among normotensive Ministry of Health staff aged 20 - 56 years (mean age 35.08, SD 9.78) in 14 states and a research institute. Respondents were recruited using quota sampling. Data collection was conducted from December 2011 to February 2012. A single urine sample was collected over 24 hours for sodium concentrations and calculated as 95.0% of total daily sodium intake. Results: Among the 471 enrolled respondents, 445 (94.0%) provided complete information on socio-demography and urine samples. Mean urine sodium excretion was 142.0 mmol/day (SD 71.7), which is equivalent to 3429 mg sodium/day or 8.7 gm of salt intake (1.75 teaspoon, which exceeds the Malaysian recommendation of 2000 mg sodium/day by 1.7 times. About 79.0% (n=353) of respondents (88.0% male and 73.0% female) had daily sodium consumption that was above the recommendation. Excretion was significantly higher among males at 161.7 mmol/day (SD 78.1) (3726 mg sodium/day) than females, 125.3 mmolfday (SD 61.1) (2875 mg/day). There was a positive, low correlation between BMl and sodium intake (r=0.216, p
    Matched MeSH terms: Blood Pressure
  14. Mohd Adzim Khalili, R.,, Norhayati, A.H., Rokiah,M. Y., Asmah, R., Siti Muskinah, M., Abdul Manaf, A.
    MyJurnal
    This study was conducted to determine radical scavenging activity and vitamin antioxidant composition in red pitaya from organic plantation. For antioxidant vitamins analysis, a reverse-phase high performance liquid chromatography was used and radical scavenging activity of methanolic and water extract were determined using 1,1-diphenyl-2-pircrylhydrazyl assay. Results for radical scavenging activity, red pitaya methanolic extract achieved the highest percentage 70.13% compared with water extract (47.13%). Antioxidant vitamins composition in red pitaya showed that the concentration of vitamin A is 120.13 ± 0.69 μg/100 g freeze-dried sample, vitamin C is 540.27 ± 0.59 μg/100 g fresh samples and vitamin E is 105.67 ± 0.56 μg/100 g freeze-dried samples. This shows that red pitaya may become an alternative and potential source of natural antioxidant.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  15. Mohd Zainol, M.K., Abdul-Hamid A., Abu Bakar, F., Pak Dek, S.
    MyJurnal
    The effect of different drying methods on the degradation of flavonoids in Centella asiatica was evaluated. C. asiatica leaf, root and petiole were dried using air-oven, vacuum oven and freeze drier. Flavonoid was determined utilizing reverse-phase high performance liquid chromatography (RP-HPLC). Results of the study revealed the presence of high concentration of flavonoids in C. asiatica leaf, root and petiole, which include, naringin (4688.8 ± 69 μg/100 g, 3561.3 ± 205 μg/ 100 g, and 978.3 ± 96 μg/ 100 g), rutin (905.6 ± 123 μg/ 100 g, 756.07 ± 95 μg/ 100 g, and 557.25 ± 58 μg/ 100 g), quercetin (3501.1 ± 107 μg/ 100 g, 1086.31 ± 90 μg/ 100 g, and 947.63 ± 83 μg/ 100 g) and catechin (915.87 ± 6.01 μg/ 100 g, 400.6 ± 67 μg/ 100 g, and 250.56 ± 18 μg/ 100g). Luteolin, kaempferol and apigenin on the other hand, were inconsistently present in some parts of C. asiatica. Air-oven treatment resulted in the highest total flavonoids degradation followed by vacuum oven and freeze dried with percent degradation of 97%, 87.6% and 73%, respectively. Catechin and rutin were found to be the most stable flavonoids with percent degradation up to 35%, 66% and 76% for freeze dried, vacuum oven and air oven, respectively.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  16. Ayub, M.Y., Norazmir, M.N., Mamot, S., Jeeven, K., Hadijah, H.
    MyJurnal
    The objective of this study was to determine the physicochemical properties of pink guava (Psidium guajava) puree and its anti-hypertensive effect on Spontaneous Hypertensive Rats (SHR). Antioxidant activities of pink guava puree in water and ethanol extracts, based on 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, were 1.43±0.04 mg/gfm and 0.28±0.01 mg/gfm, respectively. A total of 24 male SHRs were divided into a control group, CG, and 3 treatment dosage groups [low dose group, LDG (0.5 g/kg body weight/day), medium dose group, MDG (1.0 g/kg body weight/day), and high dose group, HDG (2.0 g/kg body weight/day)]. Final body weights for treatment dosage groups were lower [MDG (313.01±31.25 g), HDG (318.56±17.96 g), LDG (320.01±22.70 g)] compared to CG (331.08±41.29 g). Final systolic blood pressure values from the beginning and the end of the experiment in MDG and HDG were 231-179 mmHg and 246-169mm Hg, respectively. These results were significantly lower when compared with CG (241-223 mmHg) from the beginning until the end of the experiment. As a conclusion, these results showed that pink guava puree has anti-hypertensive properties.
    Matched MeSH terms: Blood Pressure
  17. Sun, J., Jiang, Y., Amin, I., Li, Z., Prasad, K.N., Duan, X., et al.
    MyJurnal
    This research was to determine nutritional composition, essential and toxic elemental content, and major phenolic acid with antioxidant activity in Kadsura coccinea fruit. The results indicated that Kadsura coccinea fruit exhibited the high contents of total protein, total fat, ash and essential elements such as calcium (Ca), ferrum (Fe) and phosphorus (P). The levels of four common toxic elements, i.e. cadmium (Cd), mercury (Hg), arsenic (As) and lead (Pb), were lower than legal limits. By high-performance liquid chromatography (HPLC) analysis, gallic acid was identified as major phenolic acid in peel and pulp tissues. Its contents were no significant difference in both tissues. In comparison with two commercial antioxidants, the major phenolic acid extracted from Kadsura coccinea exhibited stronger 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity and reducing power. Kadsura coccinea fruit is a good source of nutrition and natural antioxidant. It is worthwhile to popularize this exotic fruit around the world.
    Matched MeSH terms: Chromatography, High Pressure Liquid
  18. Chan, P.W.K., Cheong, B., Nadarajan, K., Lai, B.H., Cham, W.T., Khoo, K.K., et al.
    MyJurnal
    The objective of the study was to determine the prevalence of hypertension in healthy primary school children. A cross-sectional survey by manual blood pressure measurement of healthy children aged 6-12 years attending a national type school was carried out. Children with previous renal, cardiac and endocrine disorders were excluded. Korotkoff 1 represented the systolic blood pressure (SBP) and Korotkoff 5 was taken as the diastolic blood pressure (DBP). Hypertension was defined as the SBP or DBP above the 95th centile according to age group and sex regardless of ethnicity. A total of 1756 children were studied with 895 boy and 861 girls. The results showed that 109 children (6.2%) were found to have hypertension and the incidence was similar in boys and girls (6.4% vs 6.0%, p = 0.69). Fifty-three (48.6%) children had an elevated SBP and the DBP was elevated in 43 (39.4%) children. Only 12 (12.0%) children had both elevated SBP and DBP. Children found to have hypertension were more likely to be Chinese (p = 0.009) and obese (p = 0.04). In conclusion the overall prevalence of hypertension in children aged 6-12 years based on a single blood pressure measurement was 6.2%. Hypertension was more likely to be found in Chinese children and those who were obese.
    Matched MeSH terms: Blood Pressure
  19. Sri Asliza, M.A., Zaheruddin, K., Shahrizal, H.
    MyJurnal
    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.
    Matched MeSH terms: Pressure
  20. Palaniandy, Samayamutthirian, Noorina Hidayu Jamil, Khairun Azizi Mohd Azizli, Syed Fuad Saiyid Hashim, Hashim Hussin
    MyJurnal
    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.
    Matched MeSH terms: Pressure
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