Showing papers by "Universiti Sains Malaysia published in 1991"
TL;DR: In this article, the β-carotene contents of forty vegetables and fourteen fruits were determined using the AOAC open-column (magnesia and Hyflo Super Cel mixture) chromatographic method and compared with a newly developed reverse phase HPLC method, in which carotenoids were separated isocratically on an octadecylsilane (C 18 ) column using a ternary mixture of acetonitrile, methanol and ethyl acetate.
159 citations
TL;DR: The results indicate that even under harsh tropical conditions, the mangrove photosynthetic machinery is capable of operating efficiently at low light and with maximal rates of more than 15 μmol CO2 m-2 s-1.
Abstract: In this report, we analyze the photosynthetic capacity and performance of leaves under field conditions with a case study based on the mangroves Bruguiera parviflora and B. gymnorrhiza. Using a tower through a closed canopy at a field sight in North Queensland and portable infra-red gas analyzers, a large data set was collected over a period of 11 days early in the growing season. The set was used to analyze the relationship between net photosynthesis (Pnet) and light, leaf temperature, stomatal conductance and intracellular CO2 (Ci).
92 citations
TL;DR: It is shown that the generalised Ball basis for odd degree polynomials on a finite interval has a totally positive collocation matrix and thus possesses the same kind of shape preserving properties as the Bernstein basis, though to a lesser degree.
75 citations
TL;DR: The generalized Ball representation for a polynomial curve is much better suited to degree raising and lowering than the Bezier representation, and recursive algorithms for evaluation and degree raising are given.
Abstract: It is shown that the generalized Ball representation for a polynomial curve is much better suited to degree raising and lowering than the Bezier representation The generalized Ball basis is then extended to polynomial surfaces over a triangle, and recursive algorithms for evaluation and degree raising are given
54 citations
TL;DR: In this article, the scorch property of accelerated sulfur vulcanization of expoxidized natural rubber (viz ENR 10, ENR 25, and ENR 50) was studied by using Mooney Shearing Disk Viscometer in the temperature range of 100-180°C.
Abstract: The scorch property of accelerated sulfur vulcanization of three grades of expoxidized natural rubber (viz ENR 10, ENR 25, and ENR 50) was studied by using Mooney Shearing Disk Viscometer in the temperature range of 100–180°C Effects of accelerator types, concentration of accelerator, and carbon black on ENR 10 were also determined Results obtained indicate a similar scorch behavior as that reported earlier for SMR L However, some differences in the magnitude of scorch times in the temperature and concentration studies are observed between ENR and SMR L These differences are attributed to the activation of a double bond by the adjacent epoxide group in ENR, the effect being more significant for a higher degree of epoxidation of natural rubber In the case of ENR 50, differential scanning calorimetry measurement suggests that additional crosslink occurs via a ring-opening reaction at about 155°C Based on first-order reaction kinetics, the apparent activation energy of vulcanization for the rubbers studied is estimated and discussed
52 citations
01 Jan 1991-International Journal of Radiation Applications and Instrumentation. Part A. Applied Radiation and Isotopes
TL;DR: In this article, linear attenuation coefficients of a range of tropical hardwoods have been determined at a photon-energy of 59.54 keV, and good accord with mass-density linear dependence is demonstrated.
51 citations
TL;DR: The major alkaloids present in very young leaves of Mitragyna speciosa from Malaysia were shown to be highly conjugated indoles, mitragynaline and corynantheidaline, and two others were isolated and characterized.
51 citations
TL;DR: Screening audiometric test and otological examination if conducted by the school health medical officers regularly will be able to detect almost all the cases with hearing loss and middle ear disorders.
48 citations
TL;DR: A review of the state-of-the-art analytical methods for the study of carotenoids and retinoids, particularly in foods and blood samples, can be found in this article.
47 citations
TL;DR: The Sungai Merbok estuary is characterized by a 1.7 m semidiurnal tide with a 0.16 form number, peak currents of 1.3 m s−1, and mean freshwater discharge of 20 m3 s− 1 as mentioned in this paper.
Abstract: The Sungai Merbok estuary, in wet tropical Peninsular Malaysia, borders the Straits of Malacca. Tide, current, and salinity data are used to describe the salient hydrographic features of the mangrove-fringed system. The Sungai Merbok estuary is characterized by a 1.7 m semidiurnal tide with a 0.16 form number, peak currents of 1.3 m s−1, and mean freshwater discharge of 20 m3 s−1. The system is classified as 2a/2b estuary (Hansen and Rattray 1966) or 1a/1b during periods of low runoff. Gravitational circulation is highly variable (but coincides with the neap stratification) and vertical stratification varies from 10−2 to 1. The estuary displays a pronounced fortnightly neap-spring stratification-destratification cycle. The effective longitudinal dispersion coefficient is approximately 100 m2 s−1.
40 citations
TL;DR: In this paper, a study of the temperature parameter on the thermosonic gold wire bonding of high-speed CMOS using a Shinkawa bonding machine (type UTC-10) was performed to determine the lowest possible bonding temperature.
Abstract: A study of the temperature parameter on the thermosonic gold wire bonding of high-speed CMOS using a Shinkawa bonding machine (type UTC-10) was performed to determine the lowest possible bonding temperature. A full factorial statistical design of experiments to test the bonding temperature, bond force, and ultrasonic power parameters at three levels of setting each was carried out. Bond quality was evaluated using the ball shear test, wire bond pull test, and nonsticking on pad (NSOP) criteria. A smashed ball, bond to interconnect, and cratering defects were also investigated. The results show that the lowest possible temperature for bonding a particular high-speed CMOS metallization is 160 degrees C. At this temperature, satisfactory bond quality can be obtained when the bond force and ultrasonic power parameters settings are within 30-50 g and 314-471 mW, respectively. >
TL;DR: A method of constructing a triangle interpolant which interpolates position and partial derivatives specified at the three vertices of the triangle using the cubic Bezier triangular patch technique.
Abstract: We present here a method of constructing a triangle interpolant which interpolates position and partial derivatives specified at the three vertices of the triangle. The method employs the cubic Bezier triangular patch technique. The data given enable us to determine the appropriate Bezier control points so that adjacent patches meet with C1 continuity. However, the interior control point for the patch is replaced by three separate points, due to the implementation of three local schemes, each of which satisfies the boundary conditions on only one side of the triangle. Convex combination is used to blend these three local schemes.
TL;DR: In this paper, the densities and viscosities of octanoic, decanoic and dodecanoic acids with carbon number ranging from 4 to 18 at 4 temperatures from 20°C to 75°C with reasonable agreement with the experimental values.
Abstract: The densities and viscosities of octanoic, decanoic, dodecanoic and tetradecanoic acids were determined at temperatures ranging from 20 to 80°C. When the fluidities were plotted against the molal volumes of the acids, curves were obtained. The intrinsic volumes were determined by extrapolation to zero fluidity and compared with previously reported values. Based upon Hildebrand’s equation for non- associated liquids, semiempirical equations relating the fluidity with the carbon number were obtained. The equations predict the fluidities of fatty acids with carbon number ranging from 4 to 18 at 4 temperatures from 20°C to 75°C with reasonable agreement with the experimental values.
Journal Article•
TL;DR: The dot EIA technique provides a simple and useful method for the serodiagnosis of typhoid using a single serum specimen and suggests either recent or current infection.
Abstract: A nitrocellulose membrane strip dotted with a specific 50 kDa outer membrane protein of Salmonella typhi was applied for the serodiagnosis of typhoid fever. Using horseradish peroxidase conjugated IgM and IgG antibodies with 4-chloronaphthol as substrate, antibodies in typhoid patients were clearly visualised as bluish purple dots while sera from patients with non-typhoid fevers gave negative results. The detection of specific IgM and IgG antibodies in typhoid patients suggest either recent or current infection. Combined with the high specificity, reliability and rapidity of the test, the dot EIA technique provides a simple and useful method for the serodiagnosis of typhoid using a single serum specimen.
TL;DR: Results indicate the usefulness of the specific antigen in the development of a serodiagnostic test for typhoid fever since antibodies of both the IgM and IgG class responses were obtained.
Journal Article•
TL;DR: The IgM capture ELISA is compared with the dot enzyme immunoassay and the results are discussed in the context of dengue endemicity.
Abstract: This study describes the use of an IgM capture ELISA using cell culture derived antigens and a polyclonal rabbit antiflavivirus antisera for the detection of dengue positive cases. The IgM capture ELISA is compared with the dot enzyme immunoassay and the results are discussed in the context of dengue endemicity.
Journal Article•
TL;DR: A routine laboratory examination for the detection of Cryptosporidium in the search for causal agents of childhood diarrhea in the authors' environment may, therefore, be significant.
Abstract: Stool samples from 836 cases with diarrhea and acute gastroenteritis from the Pediatric ward, Penang General Hospital, were examined for Crypto.lporidium oocysts. A dimethyl sulfoxide modified acid fast technique was used for the identification of the parasites. 36 samples or 4.3'X, were found to be positive for Cryptosporidium. The prevalence of infection was higher (2.39%) in children with diarrhea and vomitting than in children with acute gastroenteritis alone (0.8%). Stool examination and cultures from the Cryptosporidium positive samples revealed no other parasites, rotavirus or enteropathogenic bacteria. This suggests that Cryptosporidium may be an important agent in the causation of diarrhea in young children. A routine laboratory examination for the detection of Cryptosporidium in the search for causal agents of childhood diarrhea in our environment may, therefore, be significant.
Journal Article•
TL;DR: A total of 38 cases of fireworks related injuries from Hospital USM over a 5-year period from 1986 to 1990 during Hari Raya festival were analysed and 24 cases suffered permanent disabilities mostly finger amputations.
Abstract: Summary A total of 38 cases of fireworks related injuries from Hospital USM over a 5-year period from 1986 to 1990 during Hari Raya festival were analysed. The majority (68.5%) of the patients were teenagers, between 10 to 19 years of age. All the cases were Malays and most of the accidents occurred before the Hari Raya Idilfitri festi ve seasons. Fourteen cases were caused by self-made fireworks and another 16 cases were due to modified fire-works. Twenty-four cases suffered permanent disabilities mostly finger amputations. Such injuries could be prevented by law enforcement coupled with public health education to modify social behaviour especially when the ban against the use of fireworks is lifted on religious grounds.
TL;DR: In this paper, the reaction of 1-[3]-methoxyphenylimino)methyl]-2-naphthol with dimethyltin(IV) dichloride yields an addition compound having 2:1 stoichiometry (ligand: organotin).
TL;DR: In this article, the authors examined various management options to control the pollution in the Inner Johore Strait, which involve partial opening as well as complete removal of the Causeway to improve the tidal flow for more effective dilution and dispersion of pollutants.
Abstract: Coastal waters in South Johore, Malaysia are polluted to various degrees. The major pollution sources are domestic wastes from human settlements, agro-based wastes from palm oil mills and rubber processing factories, industrial effluents from industrial estates and discharges from animal farms. These pollution problems have adversely affected resources such as fisheries, recreational potential as well as the general aesthetic quality of the coastal environment particularly the Inner Johore Strait. Hence proper management and control measures are urgently needed to protect and further enhance the water quality to ensure environmentally sustainable development. This study examines various management options to control the pollution in the Inner Johore Strait. The options involve partial opening as well as complete removal of the Causeway to improve the tidal flow for more effective dilution and dispersion of pollutants. Computer simulation models are used to assess the impacts of the proposed options.
TL;DR: In Malaysia, recent amendments to the Environmental Quality Act (1974), Prescribed Activities (EIA Order, 1987), have now made it mandatory for environmental impact assessment to be carried out for specific activities as mentioned in this paper.
Journal Article•
TL;DR: The data obtained show that the DEIA can be effectively used at a serum dilution of 1:1000 to confirm presumptive recent d Dengue in patients with a second dengue infection, however, demonstration of seroconversion proved necessary for patients with primary dengued.
Abstract: A dot enzyme immunoassay (DEIA) for the detection of antibodies to dengue virus was tested for use as a tool in the presumptive diagnosis of dengue fever and dengue haemorrhagic fever. Paired sera from the following groups of patients were tested using the DEIA and the haemagglutination inhibition (HI) test: those with primary dengue fever; those experiencing a second dengue infection; and febrile patients who did not have dengue. The data obtained show that the DEIA can be effectively used at a serum dilution of 1:1000 to confirm presumptive recent dengue in patients with a second dengue infection. However, demonstration of seroconversion proved necessary for patients with primary dengue. At a serum dilution of 1:1000 the DEIA has a specificity of 97.3%. The role of this simple and rapid test in improving the effectivity of programmes for the control of dengue virus infection is discussed.
TL;DR: It is suggested that substances directed to reduce the activation of KKS may provide a pharmacological basis for the synthesis of novel antirheumatic or anti-inflammatory drugs.
TL;DR: In this article, the metal(II) chelates of L threonine (metal = copper, nickel, cobalt and zinc) result in the formation of the metal-II complexes of 5-methyloxazolidine-4-carboxylic acid.
TL;DR: In this article, the applicability of carbon dioxide pressure leaching for the extraction of high purity from low grade magnesites and waste dumps material has been investigated and optimum values were determined.
TL;DR: In this article, the reaction of bis(β-alaninato)copper with formaldehyde and ammonia over the pH range 6.6-8.8 results in the formation of [3N,7N-(1,3,5,7-tetraazabicyclo[3.1]nonyl)-di-3-propionato]copper(II) trihydrate, C11H24N4O7Cu, which crystallizes in the monoclinic space group P2t/c with a =
Abstract: The reaction of bis(β-alaninato)copper(II) with formaldehyde and ammonia over the pH range 6.6-8.8 results in the formation of [3N,7N-(1,3,5,7-tetraazabicyclo[3.3.1]nonyl)-di-3-propionato]copper(II) trihydrate, C11H24N4O7Cu, which crystallizes in the monoclinic space group P2t/c with a = 10.903(2), b = 7.340(2), c = 19.435(3) A, β = 98.27(1)[ddot] and Z = 4. The structure has been refined to R = 0.040 and R w = 0.044 based on 2655 reflections with I ≥ 2.5σ(I). The chelate molecules are linked in chains by a carbonyl oxygen to copper interaction which results in square pyramidal coordination of the copper ion.
TL;DR: Five patients with type IVa choledochal cysts and cylindrical dilatation of major intrahepatic ducts who underwent cyst excision and Roux-en-Y hepaticojejunostomy are reported.
Abstract: Type IVa choledochal cysts with cylindrical dilatation of the intrahepatic ducts constitute a relatively less recognized variety of choledochal cysts, and differ from cystic dilatation of intrahepatic ducts in their clinical manifestations and response to treatment. Five patients with type IVa choledochal cysts and cylindrical dilatation of major intrahepatic ducts who underwent cyst excision and Roux-en-Y hepaticojejunostomy are reported. The duration of symptoms was less than 1 year in all patients. Palpable abdominal mass and abdominal pain were present in 3 patients. The traid of jaundice, abdominal pain and mass was present in only 1 patient. The intrahepatic dilatation regressed after excision of the extrahepatic cyst just below the hilum of the liver. The surgical technique is described and the need for excision of the cyst is emphasized.
TL;DR: CGP 20376, a 5-methoxyl-6-dithiocarbamic-S-(2-carboxy-ethyl) ester derivative of benzothiazole, had complete adulticidal and microfilaricidal activities against the parasite at a single oral dose of 20 mg kg-1, however, its clinical use in the present formulation is not recommended.
Abstract: An intense global collaborative effort under the leadership of the Steering Committee of the Filariasis Scientific Working Group of the Tropical Diseases Research Programme, World Health Organizati...
Journal Article•
TL;DR: Five formulations of Bacillus sphaericus including aqueous suspension BSP 1, BSP 2, technical powder ABG 6184, corncob granules ABG6185 and wettable powderABG 6232 were tested against laboratory-cultured late third/early fourth instar larvae of Mansonia uniformis in floating screened cages in small plots at swampy ditches on Penang Island, Malaysia.
Abstract: Five formulations of Bacillus sphaericus (strain 2362) including aqueous suspension BSP 1, BSP 2, technical powder ABG 6184, corncob granules ABG 6185 (potencies 2 x 10(10), 2 x 10(7), 95 x 10(10), 5 x 10(10), 5 x 10(10) spore/g, respectively) and wettable powder ABG 6232 (1,000 BS ITU/mg) were tested against laboratory-cultured late third/early fourth instar larvae of Mansonia uniformis in floating screened cages in small plots at swampy ditches on Penang Island, Malaysia Mean dosage/response values at 90% mortality levels were 693, 9532, 145, 1192 and 286 liters or kg per ha, respectively, for the formulations tested There were practically no residual effects for the formulations tested with larvae introduced at 48, 96, and 168 h post-treatment In trials of BSP 1, ABG 6184 and ABG 6185 (1 liter or 1 kg per ha) against immature Mansonia spp in impounded paddy field ditches, improved efficacy and residual effects were obtained with mean reductions of 931, 919 and 804% at days 3, 7 and 14 posttreatment, respectively