Showing papers by "University of Malaya published in 1985"

Minor constituents of palm oil

Abstract: Crude palm oil contains about 1% of minor components including carotenoids, tocopherols, sterols, triterpene alcohols, phospholipids, glycolipids and terpenic and paraffinic hydrocarbons. The nutritionally important components such as carotenes and tocopherols also improve stability of the oil. Although a highly valued product, carotene unfortunately is bleached or destroyed in refining because suitable recovery technology is not available. Thermal degradation of carotene, previously suspected of giving rise to undesirable chemicals, now is known to furnish mainly harmless hydrocarbons, most of which are removed by the deodorization step in refining. Tocopherols, being natural antioxidants, need to be carefully preserved during milling, refining, fractionation and modification of palm oils. The accumulation of tocopherols in the palm fatty acid distillate promises to provide a new source for the recovery of this valuable substance. The role played by phospholipids is frequently misunderstood because they can act in two ways, i.e. as an antioxidant synergist and a surface active agent to disperse impurities in oil. In crude palm oil the phospholipid content is small, because most of it is removed during milling; the phosphorus content is due mainly to inorganic phosphorus. Among the sterols, cholesterol constitutes too small a percentage to be of much concern. Sterols, triterpenoids and terpenoid hydrocarbons are also potentially useful side products should recovery technology become available. Other newly characterized minor and trace components also are discussed.

A New Technique in Minimal Path and Cutset Evaluation

Abstract: This paper presents a new technique for deducing the minimal paths and cutsets of a general network. A powerful concept of reducing the total number of minimal paths to its basic minimal paths is introduced. This concept reduces the computational time and required storage in deducing the minimal cutsets. A new technique for evaluating minimal cutsets has been adopted. Examples demonstrate the power of the technique in reducing the computational requirements as compared to the conventional method, and show that the task for analysing large systems now becomes trival.

Analysis of positional distribution of fatty acids in palm oil by13C NMR spectroscopy

Abstract: The13C NMR spectrum of the carbonyl carbons of the acyl groups of triacylglycerols of palm oil has been shown to give the composition of saturated, oleic and linoleic acyl groups at the 1,3-positions and at the 2-position of the glycerol moiety. Except for the lack of differentiation of the saturated fatty acids, the13C NMR technique provides the same information as the tedious enzymatic hydrolysis cum fatty acid analysis. The carbonyl carbon of the linolenic acyl group (18∶3,[cis, cis, cis]-9, 12, 15) has a chemical shift which is only 0.005 ppm to low frequency of that of the linoleic acyl group (18∶2,[cis, cis]-9, 12), so that the two resonances may not be distinguishable (or resolved) even at a high magnetic field.

The application of the pitzer equations to 1-1 electrolytes in mixed solvents

Abstract: Pitzer's equation for the activity coefficient has been applied to LiCl, NaCl, KCl, RbCl, CsCl, and HCl in methanol-water mixtures at 25°C. The two parameters, β MX (0) and β MX (1) , were obtained by the method of least squares. The same values of b and α as for aqueous systems could be used for the methanol-water mixtures without greatly affecting the standard deviation of the fit. β MX (0) was found to decrease with methanol content for the alkali metal chlorides whereas β MX (1) was found to increase. For HCl, however, a slight maximum and a minimum were found in the values of β MX (0) while a maximum was observed in the values of β MX (1) .

DSC studies of linear low density polyethylene. Insights into the disrupting effect of different comonomers and the minimum fold chain length of the polyethylene lamallae

Abstract: This paper reports a DSC examination of a series of linear low density polyethylenes (LLDPE) prepared variously with propylene, 1-butene or 4-methyl-1-pentene comonomers. The enthalpy of fusion of the crystalline regions of the LLDPE decreases progressively with increasing comonomer content and is effectively independent of the comonomer type. Disruption of polymer crystallinity is thus determined principally by the number and distribution of the chain irregularities. A sequence length of n = 14 was calculated as the critical chain dimension below which polyethylene segments cannot be readily packed into a stable crystal lattice.

Characterisation of the weathering profile developed over a porphyritic biotite granite in peninsular Malaysia

Abstract: Nine stages of weathering of a porphyritic biotite granite bedrock material have been distinguished on the basis of differences of colour, texture and the extent of alteration of mineral grains. Determination of the distribution pattern of the different stabes of weathering of bedrock material within the weathering profile then allowed for recognition of six stages of weathering of the bedrock considered on the scale of the mass. Characterisation of the weathering profile over the prophyritic biotite granite bedrock thus involved recognition and definition of weathering of the bedrock, both on the scale of the hand specimen, i.e. as rock material, and on the scale of the mass, i.e. as rock mass.

Stevens‐Johnson Syndrome

Abstract: Abstract: Stevens‐Johnson syndrome is relatively rare. The authors report a retrospective study of 34 patients seen at the University Hospital in Malaysia over 16 years and discuss the epidemiology, clinical features, complications, investigations, etiologic association, mortality, sequelae, course of the disease, and the use of steroid.

Anaerobic treatment of palm oil mill effluent by tank digesters

Abstract: Palm oil mill effluent was treated anaerobically in 210 dm−3 tank digesters in which inoculation with anaerobic seeding coupled with careful addition of lime could shorten the natural stabilisation process to about 30 days. The system was subsequently scaled up to 500 tonnes capacity. The characteristics of the anaerobically digested liquors were studied at 10 and 20 days hydraulic retention time (HRT) respectively, and close to 90% treatment efficiency could be achieved at 20 days HRT with complete microbial conversion of plant cell debris. However, the digested liquor still contained 0.325% (by wt) suspended solids. The kinetics of the anaerobic process show close resemblance to those treating other high strength organic wastes. Optimum gas production occurred only over a narrow pH range of 6.8–7.2 units. A methane content of 62–67% on gas production was noted about equivalent to 0.34 to 0.39 dm−3 CH4 g−1 of BOD destroyed.

A review of Malaysian freshwater copepoda with notes on new records and little known species

Abstract: Twenty species of freeliving Cyclopoida occurring in freshwaters of Peninsula Malaysia were recorded. Twelve species are new records. Illustrated descriptions of these species are given. A list of Malaysian Calanoida is given. Cosmopolitanism is discussed with reference to Mesocyclops, Macrocyclops, and Thermocyclops.

Comparative studies of three solvent mixtures for the extraction of soybean lipids

Abstract: Soybean seeds were extracted with chloroform-methanol (2:1), methylene chloride-methanol (2:1) and hexane-isopropanol (3:2) mixtures The seed lipids were then fractionated by column chromatography Neutral lipids were further separated by thin layer chromatography (TLC) and quantified by acid charring method Fatty acid methyl esters were prepared and analyzed by gas liquid chromatography (GLC) Our results show that methylene chloride-methanol (2:1) was as good as chloroform-methanol (2:1) for the extraction of soybean lipids, but hexane-isopropanol (3:2) was somewhat inferior

The rôle of fat and protein during breeding in the White‐bellied swiftlet (Collocalia esculents)

Abstract: The breeding biology of the White-bellied swiftlet was studied in Malaysia. Birds were captured every month, and more intensively during the breeding season. To investigate the role of fat and protein reserves in the annual cycle, carcasses were fat extracted after separating the pectoral muscles. The stage of the laying cycle was investigated by histological examination of the ovaries. Fat and protein reserves were correlated with the body size of the birds. In non-laying females and males, both reserves were correlated with date and feeding conditions determined by the weather. In egg-laying birds, protein reserves were again correlated with feeding conditions, but fat reserves were negatively correlated with the day of the laying cycle. Assessment of the daily foraging abilities of the birds showed that, for egg-layers, proteins were likely to be in greatest supply and fats in least supply. It is suggested that a fat reserve serves as an insurance against poor feeding conditions for laying birds.

Mono- and di-selenium complexes of chromium. Syntheses and crystal structures of (η5-C5H5)2Cr2(CO)4Se and (η5-C5H5)2Cr2(CO)4Se2

Abstract: The reaction of dicyclopentadienylhexacarbonyldichromium with elemental selenium at ambient temperature provides a simple route to (η5-C5H5)2Cr2(CO)4Se (1) and (η5-C5H5)2Cr2(CO)4Se22 in high yields.

Investigation of an animal model of a Reye-like syndrome caused by Margosa oil.

Abstract: Following reports of a Reye-Iike syndrome in children resulting from Margosa oil (MO) ingestion, we administered MO to laboratory rats in an attempt to produce an animal model of Reye's syndrome. Male rats were injected intraperitoneally with either MO or corn oil and observed for clinical signs of a toxic response. After 15 h the animals were administered a second dose and the MO-treated animals developed florid neurological symptoms. The animals were then sacrificed and blood samples were analyzed for glucose, ammonia, aspartate aminotransferase, and alanine aminotransferase. Sections of liver, kidney, and brain were examined by light microscopy after Sudan black B, hematoxylin and eosin, and periodic acid- Schiff staining. Liver was additionally examined by electron microscopy. Liver samples were analyzed for hepatic enzyme levels and brain samples were analyzed for water content. There were greatly increased levels of ammonia, aspartate aminotransferase, and alanine aminotransferase and decreased glucose levels in the blood of MO-treated animals. Light microscopy of MO-treated livers revealed fatty infiltration, granularity of the cytoplasm with normal nuclei, and glycogen depletion; electron microscopy revealed mitochondrial pathology in the livers of MO-treated animals. There were no significant morphological changes in brain or kidney specimens although the kidneys did show some fatty infiltration. Hepatic mitochondrial enzyme levels were unchanged and there was no increase in brain water content in the MO-treated animals. Thus, many of the abnormalities seen in Reye's syndrome were seen in this model; however, there were no hepatic enzyme changes despite altered mitochondrial morphology and no evidence of cerebral edema despite a florid encephalopathy. Nonetheless, this model may have important implications for the understanding of the pathogenetic mechanisms of this Reye-like syndrome and, perhaps, Reye's syndrome.

Performance comparison of two exact outage simulation techniques

Abstract: The paper compares the performance of two exact load-flow and outage simulation techniques. The second-order Newton-Raphson technique is described first, where the voltages are represented in rectangular co-ordinates. Then the power-flow solution by the method of reduction and restoration is described. Both methods use the complete Taylor series expansion of the nodal equations but the latter is different in that (a) only voltage-controlled busbars are retained during the iterative process, (b) a smaller-order Jacobian is used, and (c) on convergence the system is restored to the original size. Outages are simulated using the current injection principle for both techniques. The advantages and disadvantages of both are discussed.

Cardiac glycosides, calcium and the release of neurotransmitter from peripheral noradrenergic nerves

Abstract: 1. The requirement for external Ca (Cao) of neurotransmitter release evoked by cardenolides has been investigated in canine saphenous vein. 2. Basal efflux of3H-compounds from saphenous veins pre-loaded with3H-noradrenaline was the same in the absence as in the presence of Cao; Cao is not required for basal efflux of neurotransmitter. 3. Efflux of3H-compounds was increased by cardenolides. Both ACS and ouabain caused a similar maximum net efflux of3H suggesting that each evokes release from the same pool of3H compounds. 4. The similarity of the effects obtained with cardenolides to those obtained during exposure of saphenous vein preparations to potassium-free media suggests that3H-efflux is the result of Na, K-ATPase inhibition. 5. With ACS (ca. EC50) the net efflux of3H-compounds early (<60 min) in the release period was greater in the absence of Cao than in its presence whereas at longer times the reverse was true; net efflux was less in the absence of Cao than in its presence. The difference in the3H-efflux pattern was paralleled qualitatively throughout by efflux of3H-noradrenaline. 6. The ACS-evoked efflux of3H-compounds in the presence and absence of Cao derives from sympathetic, noradrenergic nerves;3H present in extraneuronal tissues was not released by the cardenolide. 7. With ouabain ( EC50): the total efflux of3H was less in the absence of Cao than in its presence. 8. In the presence of Cao the Ca-channel blocker VP reduced the total3H-efflux evoked by ouabain (>EC50), but did not reduce that evoked by ouabain (

Cryptophiale from Malaysia

Abstract: Cryptophiale aristata sp.nov., C. kakombensis, C. secunda sp.nov. and C. udagawae are described and illustrated from Malaysia.

Combination chemotherapy with cyclophosphamide, vincristine, procarbazine, and prednisone (COPP) in children with brain tumors

Abstract: The chemotherapeutic combination of cyclophosphamide, vincristine, procarbazine, and prednisone (COPP) was used to treat 15 children with recurrent central nervous system tumors and seven children with newly diagnosed brainstem tumors. In patients with recurrent tumors, marginal activity was seen in various histologic types. COPP chemotherapy was clearly ineffective in patients with brainstem tumors. Toxicity consisted of mild to moderate myelosuppression and neurotoxicity.

An empirical evaluation of government scholarship policy in Malaysia

Abstract: In Malaysia, government scholarships have been utilized on a large scale in order to achieve the employment restructuring objectives of the New Economic Policy (NEP). This article provides an empirical evaluation of the effectiveness of this policy instrument, based on a comprehensive survey of the 1982/83 graduates. The results show that scholarship policy is now: (1) generating a mismatch in the High-Level Manpower (HLM) market and (2) that these scholarships are distributed in a heavily regressive manner, benefiting students from the wealthier and higher-income families.