Showing papers by "National University of Singapore published in 1981"
TL;DR: This chapter reviews the origin and nature of miroglia and shows that in neural injuries such as retrograde and Wallerian degeneration, microglial cells are reactivated to become macrophages, which would assume their phagocytic activity.
Abstract: Publisher Summary This chapter reviews the origin and nature of miroglia. Microglial cells constitute a normal distinct cellular entity in the central nervous system and are identifiable by the silver carbonate staining method. In the past, the metamorphosis of microglia into phagocytic brain macrophages under pathological conditions or experimental lesions had received wide support from investigators. Although ameboid microglial cells display diverse morphological forms, they have many common features of monocytes and macrophages, both ultrastructurally and cytochemically. Experiments using 3 H'thymidine autoradiography and carbon particles as an intracellular marker have demonstrated unequivocally that circulating monocytes give rise to ameboid microglial cells that evolve to become microglia; however, not all the ameboid microglial cells transform into microglia. The mechanism wherein the ameboid microglial cells become microglia is not clear, although it seems to coincide with the development of the corpus callosum, particularly when the axons become compact because of myelination. In neural injuries such as retrograde and Wallerian degeneration, microglial cells are reactivated to become macrophages, which would assume their phagocytic activity.
189 citations
TL;DR: In this article, the authors report the recent past and current research and developments for the effective utilization of natural fibres from coconut husk, sisal, sugarcane bagasse, bamboo, jute, wood, akwara, plantain and musamba for making concrete.
145 citations
TL;DR: Ten cases of death due to heat stroke are described, all young men who collapsed during running exercise or route march and died in hospital later, due to disseminated intravascular coagulation with widespread microthrombus formation and coagulative necrosis involving many organs.
124 citations
01 Jan 1981
TL;DR: In this paper, it was shown that any two vertices in G are connected by a hamiltonian path if and only if G contains an edge joining two blue vertices and an edge connecting two red vertices.
Abstract: Let G be a graph containing a spanning subgraph H isomorphic to CmxLn where Cm denotes the cycle with m vertices (m≥3) and Ln the path with n, vertices (n≥2). Then H, in turn, contains a spanning subgraph H′ isomorphic to LmxLn. Vertices in H′ can thus be coloured by two colours, say blue and red, so that no two adjacent vertices in H′ are of the same colour. Then any two vertices in G are connected by a hamiltonian path if and only if G contains an edge joining two blue vertices and an edge joining two red vertices. This result enables us to characterize abelian group graphs G in whichany two vertices are connected by a hamiltonian path.
112 citations
TL;DR: In this paper, bank loan commitments are examined in the context of option pricing models and a valuation formula is obtained, and the partial takedown phenomenon, which is both distinctive and vexatious, is considered in detail.
Abstract: Bank loan commitments are examined in the context of option pricing models and a valuation formula is obtained. The partial takedown phenomenon, which is both distinctive and vexatious, is considered in detail. Finally, estimates of the value of U.S. bank loan commitments and their sensitivity to interest rate changes are provided.
78 citations
TL;DR: This article describes two procedures for calculating a lower bound on the optimal objective function when a proposed solution is given.
Abstract: The single-facility location model with Euclidean distances and its multifacility and lp distance generalizations are considered. With present algorithms a user is unable to decide how close to optimal any given feasible solution is. This article describes two procedures for calculating a lower bound on the optimal objective function when a proposed solution is given.
66 citations
TL;DR: Of 710 patients in whom renal biopsies with immunofluorescence, light and electron microscopic and clinical data were available, 239 had idiopathic mesangial IgA nephritis, and the disease was the commonest type of primary glomerulonephritis in Singapore.
Abstract: Of 710 patients in whom renal biopsies with immunofluorescence, light and electron microscopic and clinical data were available, 239 had idiopathic mesangial IgA nephritis. In these 239 cases IgA was found alone in 45.7%, accompanied by IgG in 50.1%, IgM in 21.4%, C3 in 82.4% and fibrin in 37.2%. Serum immunoglobulin levels including IgA were not significantly raised, and complement C3 activation was via the alternative pathway. There was a wide range of glomerular lesions with minor change, minor change with focal and segmental lesions including sclerosis and mesangial cell hypercellularity, diffuse mesangial cell proliferation and, infrequently, diffuse sclerosing glomerulonephritis. The glomerular lesions were related to the stage, duration and severity of the disease. There was also a wide variability of clinical presentations, with asymptomatic and symptomatic microscopic haematuria-proteinuria, macroscopic haematuria, recurrent proteinuria, nephrotic syndrome, acute nephritis, hypertension, and uncommonly as acute renal failure and potassium losing nephritis. No aetiological agent was found, and both the streptococcus and HBsAg could not be identified. The disease(s) was the commonest type of primary glomerulonephritis (33.7%) in Singapore, another geographic area in addition to Japan and France, where this lesion has an apparent high incidence.
60 citations
Federal University of Bahia1, Siriraj Hospital2, Post Graduate Institute of Medical Education and Research3, University of Western Ontario4, University of Southern California5, University of Zambia6, University of Chile7, Seoul National University8, National University of Singapore9, Karolinska University Hospital10, University of Sydney11
TL;DR: Bioavailability as measured by the area under the serum ethynyloestradiol concentration-time curve showed more than a ten-fold variation and intra-centre differences in the various parameters measured were as large as the inter-centres differences.
51 citations
TL;DR: In this article, a sandwiched thermocouple technique was developed to measure the grinding temperature, which has the advantage of not requiring individual calibrations when different workpieces are used.
50 citations
TL;DR: Findings indicate that the motor response to sympathomimetic amines is the result of activation of alpha-adrenoreceptors in the corpus cavernosum muscle, which is likely to be either of the beta 1 or beta 2 type.
Abstract: 1. Adrenaline, noradrenaline and phenylephrine caused contraction of the corpus cavernosum muscle of the human penis. These sympathomimetic amines did not product inhibitory effects even in the presence of the alpha-adrenoreceptor blocker, phentolamine. The effect of dopamine was similar to that produced by these three sympathomimetic amines. Higher doses of isoprenaline and salbutamol also contracted this preparation. 2. Cocaine and guanethidine enhanced the motor response to adrenaline, noradrenaline and phenylephrine while the action of dopamine was blocked by these two drugs. 3. The motor response to adrenaline, noradrenaline and phenylephrine was antagonized by phentolamine and often potentiated by the beta-adrenoreceptors blocking drug, propranolol. The contractions produced by high doses of salbutamol and isoprenaline were also abolished by phentolamine. These findings indicate that the motor response to sympathomimetic amines is the result of activation of alpha-adrenoreceptors in the corpus cavernosum muscle. 4. At low doses, isoprenaline and salbutamol relaxed the corpus cavernosum muscle strip. The inhibitory action was blocked by low concentrations of the beta-adrenoreceptor antagonist, propranolol but not by practolol (beta 1-adrenoreceptor antagonist) and butoxamine (beta 2-adrenoreceptor antagonist). beta-adrenoreceptors are present in the corpus cavernosum muscle but these are unlikely to be either of the beta 1 or beta 2 type. The possible existence of a third type of beta-adrenoreceptor is suggested.
47 citations
TL;DR: In this article, a completely-mixed, suspended growth, continuous anaerobic fermentation system was used for the treatment of palm oil sludge in a laboratory scale and the results showed that the system was effective in the removal of BOD, COD, and volatile suspended solids.
TL;DR: In this paper, the roll-up of an initially planar semi-infinite vortex sheet with a parabolic distribution of circulation is extended to include vortex sheets exhibiting a general power law circulation distribution, resulting in the presence of a power law, and in one case a logarithmic-like, velocity field singularity.
Abstract: Kaden's problem of the roll-up of an initially planar semi-infinite vortex sheet with a parabolic distribution of circulation is extended to include vortex sheets exhibiting a general power law circulation distribution, resulting in the presence of a power law, and in one case a logarithmic-like, velocity-field singularity. Both semi-infinite and infinite initially plane sheets with this property are considered and the form of their roll-up in the similarity plane, into single and double-branched spirals respectively, is obtained numerically. Estimates of the Betz constant obtained from the solutions are found to be significantly different from values predicted by the Betz approximation.
TL;DR: Echocardiographic examinations of 21 unselected patients with systemic lupus erythematosus revealed a wide variety of abnormalities, including significantly larger left atrial and left ventricular dimensions and significantly smaller ejection fraction percentages and fractional shortening of the left ventricle.
Abstract: Echocardiographic examinations of 21 unselected patients with systemic lupus erythematosus revealed a wide variety of abnormalities. The abnormalities consisted of substantial pericardial effusion in five patients (24%) and a thickened pericardium in six patients (29%);significantly larger left atrial and left ventricular dimensions and significantly smaller ejection fraction percentages, fractional shortening of the left ventricle, and rate of early diastolic mitral valve closure compared to that in a control group of subjects; and paradoxical and hypokinetic movement of the septum in one patient (5%) each.
The presence of pericardial effusion and a thickened septum and a decrease in the ejection fraction percentage, fractional shorteningof the left ventricle, and mitral valve diastolic closing velocity showed no correlation with previous hypertension, the presence or absence of anemia, renal failure, serum levels of proteins, and duration of patients' illnesses.
Long-term follow-up studies to determine the implications of these subclinical cardiac abnormalities using noninvasive techniques (such as echocardiography) is vitally important.
TL;DR: Larves de Pilumnus vespertilio ont ete eleves en laboratoire a 26 ± 1 ° G dans de l'eau de mer filtree a 31 ± 1 pour mille de salinite, est tres proche de celles des deux autres especes.
Abstract: [Les larves de Pilumnus vespertilio ont ete eleves en laboratoire a 26 ± 1 ° G dans de l'eau de mer filtree a 31 ± 1 pour mille de salinite. Elles ont ete nourries avec des nauplii d'Artemia. Les trois stades zoe et la megalope obtenues sont decrites et figurees en detail. Le developpement de la megalope prends 6 jours au moins. Les zoes de P. vespertilio different de celles de P. dasypodus et de P. sayi par la presence d'une paire supplementaire d'epines postero-laterales sur le second somite abdominal. La megalope de P. vespertilio est tres proche de celles des deux autres especes., Les larves de Pilumnus vespertilio ont ete eleves en laboratoire a 26 ± 1 ° G dans de l'eau de mer filtree a 31 ± 1 pour mille de salinite. Elles ont ete nourries avec des nauplii d'Artemia. Les trois stades zoe et la megalope obtenues sont decrites et figurees en detail. Le developpement de la megalope prends 6 jours au moins. Les zoes de P. vespertilio different de celles de P. dasypodus et de P. sayi par la presence d'une paire supplementaire d'epines postero-laterales sur le second somite abdominal. La megalope de P. vespertilio est tres proche de celles des deux autres especes.]
TL;DR: In this article, the design of area controllers for load frequency control is considered, and the performance of the new control scheme is also compared with that obtained via the optimal state feedback law.
TL;DR: It is suggested that the patient might have either had 2 co-existing myopathies viz. multicore disease and pericentronuclear myopathy or a single entity with combinations of features which had not hitherto been described.
TL;DR: Following injection of horseradish peroxidase (HRP) solution in the gastrocnemius muscle or the extensor digitorum longus muscle in neonatal and developing albino rats, some neurones in the cervical enlargement, mid-thoracic region and sacral region were labelled.
TL;DR: Electron microscopic study showed the presence of macrophages in the retina in postnatal rat and these phagocytic cells were pleomorphic, some displayed typical features of tissue macrophage bearing prominent cytoplasmic inclusions, others resembled monocytes or microglial cells.
Abstract: Electron microscopic study showed the presence of macrophages in the retina in postnatal rat. These phagocytic cells were localized predominantly in the nerve fiber layer between the ganglion cells and the inner limiting membrane. They were pleomorphic, some displayed typical features of tissue macrophages bearing prominent cytoplasmic inclusions, others resembled monocytes or microglial cells. Their cytoplasm contained a variable number of electron-dense granules of size 0.15μm and these exhibited peroxidase activity.
TL;DR: Adenosine is shown to inhibit adenylate cyclase activity of fat cell ghosts and of purified membranes of rat fat cells and to prevent a large increase in the concentration of cyclic AMP in fat cells rather than the inhibition of lipolysis per se.
TL;DR: In this paper, an inclined corrugated parallel plates oil separator with hydraulic loading rates of 0.2 m 3 m −2 -h was used for refining crude palm oil.
TL;DR: In this article, a wood-polymer composites have been prepared using some tropical commercial woods, including Kapur (Dryobalanop sp), Kempas (Koompassia sp), Red Seraya (Shorea sp), White Seraya and Jelutong (Dyera sp).
Abstract: Radiation-induced wood-polymer composites have been prepared using some tropical commercial woods. These included Kapur (Dryobalanop sp.), Kempas (Koompassia sp.), Red Seraya (Shorea sp.), White Seraya (Parashorea sp.), and Jelutong (Dyera sp.). The wood specimens were modified by impregnation with monomers and followed by exposure to gamma radiation. Monomer systems used were methyl methacrylate, methyl methacrylate with 5% dioxane, acrylonitrile, 60:40 styrene-acrylonitrile comonomer, vinyl acetate, and vinylidene chloride. The resulting composite specimens exhibited significant increases in hardness and compressive strength, the extent of which appeared to depend on the amount and type of polymer present. Dimensional stability increased when the woods were impregnated with polymethyl methacrylate and improved further to about 35% on addition of a swelling agent, dioxane. Wood-polyvinylidene chloride composites gave high fire resistance as opposed to wood-polymethyl methacrylate which showed in...
TL;DR: The individual effects of system configuration, relative stage position and buffer capacity allocation in automatic transfer line systems were investigated through computer simulation experiments to develop a table of preferred system designs with respect to each individual factor and response.
Abstract: The individual effects of system configuration, relative stage position and buffer capacity allocation in automatic transfer line systems were investigated through computer simulation experiments. The breakdown and repair rates used in this study were 1/400, 1/200, 1/50 and 1/20 respectively. Steady-state responses on the production rate, in-process average stock and mean delay time were statistically analysed using the fixed effects analysis of variance model and Duncan's multiple range test. A table of preferred system designs with respect to each individual factor and response was developed as a useful guide for design purpose.
TL;DR: In this paper, a corona-type point source suitable for acoustic measurement purposes, especially model studies in acoustics, was described and the characteristics of this sound source were investigated and were found to be very close to those of a theoretical point source.
TL;DR: Intravenous infusion of carboprostacyclin and oral administration of relatively large doses of this compound inhibited ex-vivo ADP-induced platelet aggregation but this was accompanied by headache, facial flush, tachycardia and changes in blood pressure.
TL;DR: In this article, the surface finish, roundness and forces of tungsten carbide balls of various diameters were measured on brass, aluminium and steel specimens, with the large volume of data collected, multiple linear regression techniques were used and empirical relationships were established.
TL;DR: A Sertoli cell tumour that occurred in a true hermaphrodite with a 46, XX chromosome constitution is described and it is suggested that the tumour possessed the capacity for ectopic production of the gonadotrophins.
TL;DR: The data suggest that the host response to EBV in NPC patients is inadequate to get rid of the virus and that the persistence of this virus is responsible for the high antibody titre.