Showing papers by "Universiti Sains Malaysia published in 1989"

A generalized Ball curve and its recursive algorithm

Abstract: The use of Bernstein polynomials as the basis functions in Bezier's UNISURF is well known. These basis functions possess the shape-preserving properties that are required in designing free form curves and surfaces. These curves and surfaces are computed efficiently using the de Casteljau Algorithm. Ball uses a similar approach in defining cubic curves and bicubic surfaces in his CONSURF program. The basis functions employed are slightly different from the Bernstein polynomials. However, they also possess the same shape-preserving properties. A generalization of these cubic basis functions of Ball, such that higher order curves and surfaces can be defined and a recursive algorithm for generating the generalized curve are presented. The algorithm could be extended to generate a generalized surface in much the same way that the de Casteljau Algorithm could be used to generate a Bezier surface.

Iron and infection: the clinical evidence.

Abstract: Iron deficiency is prevalent in childhood in the developed and developing countries. Programs of presumptive therapy, mass supplementation and food fortification have been introduced in many countries. The unresolved debate over the interaction of iron and infection in the clinical setting prompts re-evaluation of these practices. Situations of iron overload are associated with increased susceptibility to certain infections, although the exact mechanisms may vary with the main pathology. Iron treatment has been associated with acute exacerbations of infection, in particular malaria. In most instances parenteral iron was used. In the neonate parenteral iron is associated with serious E. coli sepsis. In one country, with endemic malaria, parenteral iron was associated with increased rates of malaria and increased morbidity due to respiratory disease in infants. In contrast in non-malarious countries studies of oral iron supplementation have if anything shown a reduction in infectious morbidity. Methodological problems in the latter reports indicate the need for further controlled prospective studies with accurate morbidity recording if informed recommendations are to be made.

Single dose kinetic study of the triple combination mefloquine/sulphadoxine/pyrimethamine (Fansimef) in healthy male volunteers.

Abstract: A single dose pharmacokinetic study of a combined antimalarial formulation of mefloquine, sulphadoxine and pyrimethamine (Fansimef) has been performed in 10 healthy adult male Malaysian volunteers. The dose consisted of two tablets containing 250 mg mefloquine base, 500 mg sulphadoxine base and 25 mg pyrimethamine base each. Plasma concentrations of mefloquine and pyrimethamine were measured by GC-ECD, those of sulphadoxine by h.p.l.c. Time to peak concentrations (mean +/- s.d. for mefloquine (5.70 +/- 0.95 h), sulphadoxine (3.75 +/- 2.03 h) and pyrimethamine (3.30 +/- 1.98 h) were similar to those observed by others after administration of the single compounds. This was also true for elimination half-lives (t1/2). The t1/2s for mefloquine, sulphadoxine and pyrimethamine were 387 +/- 98 h, 255 +/- 61 h and 114 +/- 42 h, respectively.

A new method for the direct measurement of the energy absorption coefficient of gamma rays

Abstract: The most important primary interaction cross section of gamma radiation which is of interest in radiation dosimetry and health physics is the energy absorption coefficient μen of the medium under study. Direct measurement of μen is, however, difficult and recourse is taken to theoretical computations for its estimation. In this study a new, simple and direct method for the determination of μen is reported. The method is based on paraxial sphere transmission using a proportional-response gamma detector. The bremsstrahlung originating from photoelectrons in the absorbing medium and fluorescence radiations from shielding etc. have been suppressed by using suitable filters. The effects of nonparaxiality and of finite sample thickness have been accounted for, using extrapolation procedures. The deviation from nonproportionality and other corrections have been shown to be small. The measured value of μen for paraffin has been determined as (3.3±0.2)×10−3 m2/kg. This compares favourably with the theoretically computed value of 3.35 × 10−3 m2/kg given by Hubbell et al.

Cardiopulmonary fitness in a sample of Malaysian population.

Abstract: Lung capacity and maximum oxygen uptake (VO2max) were measured directly in 167 healthy males, from all the main races in Malaysia. Their ages ranged from 13 to 59 years. They were divided into five age groups (A to E), ranging from the second to the sixth decade. Lung capacities were determined using a dry spirometer and VO2max was taken as the maximum rate of oxygen consumption during exhaustive exercise on a cycle ergometer. Mean forced vital capacity (FVC) was 3.3 +/- 0.5 l and it correlated negatively with age. Mean VO2max was 3.2 +/- 0.2 l.min-1 (56.8 +/- 3.5 ml.kg-1.min-1) in Group A (13-19 years) compared to 1.7 +/- 0.2 l.min-1 (28.9 +/- 2.9 ml.kg-1.min-1) in Group E (50-59 years). Regression analysis revealed an age-related decline in VO2max of 0.77 ml.kg-1.min-1.year-1. Multiple regression of the data gave the following equations for the prediction of an individual's VO2max: VO2max (l.min-1) = 1.99 + 0.035 (weight)-0.04 (age), VO2max (ml.kg-1.min-1) = 67.7-0.77 (age), where age is in years, weight in kg. In terms of VO2max as an index of cardiopulmonary performance. Malaysians have a relatively lower capacity when related to the Swedish norms or even to those of some Chilean workers. Malaysians were, however, within the average norms of the American Heart Association's recommendations. Age-related decline in VO2max was also somewhat higher in the Malaysians.

Contribution of Kinin System to the Antihypertensive Action of Angiotensin Converting Enzyme Inhibitors

Abstract: Kinins are powerful vasodepressor polypeptides released by serine proteases called kallikreins from substrates, found in the circulatory and lymphatic systems, termed as kininogens There are three main kininases, however, kininase II which is also known as angiotensin converting enzyme (ACE) is clinically more important for the treatment of hypertensive disease Kininase II (ACE) causes conversion of angiotensin I (AgI) into Ag II (vasopressor), and produces inactivation of kinins Factors regulating kinin formation and biodegradation are depicted in Fig 1

Sequence of onset of different drug use among opiate addicts.

Abstract: SummaryThe temporal sequence of drug use should reveal which drugs are precursors to heroin and which drugs are used subsequent to the establishment of heroin addiction as adjunctive drugs. This temporal sequence was examined in an epidemiological study. Out of 249 opiate addicts interviewed in the area of Penang, Malaysia, this sequence of drugs could be obtained in 248 cases. The mean (median) age for first use of nicotine is 15.5 (15) years, alcohol 18.4 (18) years, cannabis 17.8 (17) years, heroin 21.8 (21) years, opium 22.8 (22) years, and benzodiazepines 25.8 (25) years. The age of first use of different drug types is presented in some detail. The patterns of sequence of drug use was analyzed for the five major and most frequently reported drugs, i.e. alcohol, cannabis, heroin, opium and benzodiazepines. Nicotine, used as first drug in almost all cases, was omitted in this analysis. A clear trend to multiple drug abuse emerges from this analysis; the biggest number of cases were users of 4 drugs (81...

Characterisation of H+ and Cu2+ binding to humic and fulvic acids

Abstract: The nature of H+ and Cu2+ binding by soil-derived humic (HA) and fulvic (FA) acid was characterised using potentiometric titrations. The experimental data obtained showed that the derived proton balance equation was valid and capable of describing proton consumption by both polyelectrolytes. HA was found to be more acidic and more reactive as shown by its lower equivalent weight compared to FA. Acid consumption by HA during titrations was little affected at ionic strength (μ) up to 0.1 M although it was enhanced at higher μ. Displacement of protons by Cu2+ resulted in a nonlinear sigmoidal pattern suggesting the formation of different Cu-HA chelates, or existence of sites that differed in their affinities for Cu on the ligand. Different concentrations of added Cu appeared to favour one or both mechanisms, although the titration method could not differentiate which of the probable mechanisms was more dominant at a specific level of Cu added. Similar values were obtained for conditional stability co...

Clinical and electroencephalographic features of complex partial seizures in infants

Abstract: The clinical and electroencephalographic (EEG) features were evaluated in a consecutive series of 50 infants with complex partial seizures. The age of onset of seizures showed a peak at age of 2 months. Significant development delay was seen in 60% of the infants. In 92% an underlying aetiological factor could be identified. Birth asphyxia was the commonest aetiological factor (30%). The seizure patterns were most frequently described as behavioural arrest, upward deviation of eyes, tonic posturing of the limbs, apnoea and cyanosis. Interictal EEG showed bilateral temporal lobe foci in 22%, unilateral foci in 78% and multiple foci in 46% of the cases. The response of the seizures to anticonvulsant drugs is discussed.

Small-angle coherent gamma-ray scattering at 662 keV for Pb and Sn

Abstract: Discrepancies between theory and experiment have been reported in the small-momentum-transfer region x A −1 for the coherent scattering of moderate-energy photons. In the present experiment an investigation has been made of the performance of each of the primary components of an annular target setup, arranged for 662 keV photon scattering at angles in the range 5°–15°. The conventional double-cone primary-beam stop is found to significantly degrade the full-energy peak-to-valley ratio compared to that obtained with a parallel-sided arrangement. Asymmetry has been found in the response of the detector to an auxiliary point source radially distributed over the scattering plane. Appropriate experimental procedures and corrections have been adopted in obtaining differential cross sections of reduced uncertainty. Results obtained on the basis of present measurements are found to be in accordance with theory. A reanalysis of an earlier set of experimentally determined differential cross sections has been produced.

Effect of inherent deformations of leadframes on bleedability of plastic dip

Abstract: Variance formed between the mold plate and the leadframe causes resin bleed on the leads of the plastic 40L Dual In-Line Package (PDIP 40L). Resin bleed affects the solderability of the package. The mechanical stamping method used in the production of the copper leadframes causes dented deformation at the edge of the leads of the leadframe. A perfect uniform flatness on the surface of the copper leadframe is also not possible. Study is carried out to investigate the effect of these inherent deformations of stamped copper leadframes' surface on the resin bleed-out of the plastic DIP. The results show that two types of bleed rejects occurred because of the stamping induced deformation found at the edge of the leads of the copper leadframes and the non uniform flatness of the surface on the copper leadframes. Resin bleedability and non-solderability can be eliminated when chemically etched copper leadframes are used for the plastic Dual-In-Line Packages.

Chemosuppression of malaria by the triple combination mefloquine/sulfadoxine/pyrimethamine: a field trial in an endemic area in Malaysia

Abstract: Malaria, particularly that due to chloroquine-resistant Plasmodium falciparum , which requires management with antimalarial drugs capable of protecting against multiresistant strains, has emerged in Malaysia. A study was carried out to assess the efficacy and tolerability of 2 dosages of mefloquine/ sulfadoxine/pyrimethamine (MSP; RO 13-5112) compared to Fansidar ® in a malaria endemic area. 914 subjects in 3 random groups were studied. Occurrence of malaria was assessed both clinically as well as by blood films. Plasma drug levels were also measured. The results showed that the low dose of MSP was completely effective in suppressing parasitaemia. 2·7% of the study population reported adverse drug reactions, the lowest incidence being in subjects on the low dose; their blood chemical profiles were also the least affected. The plasma levels of pyrimethamine and sulfadoxine achieved in the low dose group were slightly higher than expected, but there was no significant difference in bioavailability. The study showed that, for chemoprophylaxis, a low dose of MSP provided effective protection with minimal side effects.

A comparison of the effects of oral and intravenous glucose administration on renal calcium excretion in the rat

Abstract: Standard renal clearance techniques were used to compare the effects of oral and intravenous glucose administration on renal calcium handling in the rat. A significant (P less than 0.01) calciuric response was evident in both groups following glucose loading. The maximal effect in the oral group, however, was slightly delayed. The increased urinary calcium excretion in both groups was the result of a reduction in fractional calcium reabsorption. The filtered load of calcium was unchanged. The response was also independent of changes in urinary sodium output, urine flow rate and glycosuria. The role of insulin in the response remains unclear.

The Influence of Instructional Media in Physiology Practical Teaching on Students Conceptual Understanding

Abstract: A videotaped demonstration was compared with a conventional laboratory experiment in physiology for first‐year pharmacy students. The experiment was designed as an exercise in the use of the scientific method. The class was divided into a control group who performed the experiment for themselves, and an experimental group who were given the demonstration and spent most of the time analysing and interpreting the data using a semi‐programmed report sheet. After the practical session all students wrote an essay‐type report. The short‐ and long‐term gains resulting from practical work were assessed using objective pre‐ and post‐tests of cognitive performance. An answer review was given to half of each treatment group after the first post‐test. The short‐term gains were very moderate and were not significantly different for the treatment groups. The long‐term gains were significantly higher for the subgroups given the test answer review. The essay report did not reinforce the gains from the practical ...

A data-driven control strategy for grammar writing systems

Abstract: A natural-language description written in a production-type grammar writing language is defined by a set of grammar rules and a control mechanism. This paper introduces such grammer writing systems and highlights the relationship between the two components. It then proposes a data-driven control strategy, which offers several advantages over existing systems in terms of grammar development and maintenance and computational efficiency. This data-driven control strategy divides the grammar into active and inactive rules. Active rules are attached to their corresponding nodes in the test structure and only these rules participate in the pattern matching process. Upon the successful application of one rule, a new set of active rules will be derived. This derivation involves a search process, simplified by a pre-compilation of the grammar which determines the interaction between rules. This scheme also automatically partitions the grammar according to linguistic classes and provides an incremental way of writing ambiguity rules.

On formalisms and analysis, generation and synthesis in machine translation

Abstract: A formalism is a set of notation with well-defined semantics (namely for the interpretation of the symbols used and their manipulation), by means of which one formally expresses certain domain knowledge, which is to be utilised for specific purposes. In this paper, we are interested in formalisms which are being used or have applications in the domain of machine translation (MT). These can range from specialised languages for linguistic programming (SLLPs) in NIT, like ROBRA in the ARIANE system and GRADE in the Mu-system, to linguistic formalisms like those of the Government and Binding theory and the Lexical Functional Grammar theory. Our interest lies mainly in their role in the domain in terms of the ease in expressing linguistic knowledge required for MT, as well as the ease of implementation in NIT systems.

Cardiomyopathy in pregnancy: 2 case reports.

Abstract: Cardiomyopathy developed in the peripartum period in two healthy primigravida at 41 and 42 weeks of gestation are presented. In the first case, the patient presented with pulmonary oedema and had cardiac arrest immediately after admission. After resuscitation, a live baby was delivered by Caesarean section. Second cardiac arrest occurred after 12 hours of operation and the patient was resuscitated again. On the 8th post operative day, patient died of D.I.V.C. and renal failure. The second case was a twin pregnancy associated with pregnancy induced hypertension. Caesarean section was performed for foetal distress. She developed pulmonary oedema with left ventricular failure on the second post operative day, was resuscitated and discharged on the 15th day. These are the first two cases to be reported from Hospital University Sains Malaysia. Reference is made to three other cases in which a similar pathological process might have occurred.