Browse publications by year: 2004

  1. Konradsen F, van der Hoek W, Amerasinghe FP, Mutero C, Boelee E
    Acta Trop, 2004 Jan;89(2):99-108.
    PMID: 14732233
    Traditionally, engineering and environment-based interventions have contributed to the prevention of malaria in Asia. However, with the introduction of DDT and other potent insecticides, chemical control became the dominating strategy. The renewed interest in environmental-management-based approaches for the control of malaria vectors follows the rapid development of resistance by mosquitoes to the widely used insecticides, the increasing cost of developing new chemicals, logistical constraints involved in the implementation of residual-spraying programs and the environmental concerns linked to the use of persistent organic pollutants. To guide future research and operational agendas focusing on environmental-control interventions, it is necessary to learn from the successes and failures from the time before the introduction of insecticides. The objective of this paper is to describe the experiences gained in Asia with early vector control interventions focusing on cases from the former Indian Punjab, Malaysia and Sri Lanka. The paper deals primarily with the agricultural engineering and land and water management vector control interventions implemented in the period 1900-1950. The selected cases are discussed in the wider context of environment-based approaches for the control of malaria vectors, including current relevance. Clearly, some of the interventions piloted and implemented early in the last century still have relevance today but generally in a very site-specific manner and in combination with other preventive and curative activities. Some of the approaches followed earlier on to support implementation would not be acceptable or feasible today, from a social or environmental point of view.
    MeSH terms: Animals; Anopheles/parasitology; Humans; India; Insect Vectors/parasitology; Malaria/prevention & control*; Malaria/transmission; Malaysia; Mosquito Control/methods*; Regional Health Planning*; Sanitary Engineering*; Sri Lanka; Water Supply*
  2. Seet WT, Mary Anne TJ, Yen TS
    Clin Chim Acta, 2004 Feb;340(1-2):201-5.
    PMID: 14734213 DOI: 10.1016/j.cccn.2003.11.001
    BACKGROUND: Apolipoprotein E (apoE) is encoded by a polymorphic gene located on chromosome 19. The three common apoE alleles are epsilon2, epsilon3 and epsilon4. We studied the frequencies of the apoE alleles and genotypes in the three ethnic groups-Malay, Chinese and Indian-in Malaysia using DNA amplification followed by agarose gel electrophoresis.
    METHODS: EDTA blood was collected and DNA was extracted using proteinase K-SDS digestion and purified by phenol-chloroform extraction. The apoE gene sequence was amplified using the PCR and apoE genotyping was performed by restriction enzyme digestion with HhaI.
    RESULTS: Genotyping of the apoE gene produces six genotypes-E2/E2, E2/E3, E3/E3, E2/E4, E3/E4 and E4/E4. The most common apoE genotype in the Malays, Chinese and Indians studied was E3/E3, thus the most common apoE allele was epsilon3. The three common apoE genotypes were E3/E3 followed by E3/E4 and E2/E3, except in the Indians where E2/E3 was not detected. The three apoE alleles were confirmed in the Malays, Chinese and Indians except for the epsilon2 allele which was absent in the Indians.
    CONCLUSION: The combined frequency of the apoE alleles in the Malays, Chinese and Indians was 0.058, 0.829 and 0.114 for epsilon2, epsilon3 and epsilon4, respectively.
    MeSH terms: Alleles*; Apolipoproteins E/genetics*; China/ethnology; DNA/genetics; Ethnic Groups/genetics*; Gene Amplification; Genetics, Population; Genotype; Humans; India/ethnology; Malaysia; Malaysia/ethnology
  3. Lopez JB, Peng CL
    Clin Chim Acta, 2004 Feb;340(1-2):235-8.
    PMID: 14734218 DOI: 10.1016/j.cccn.2003.11.007
    MeSH terms: Adult; Aged; Aged, 80 and over; Blood Glucose/metabolism; China/ethnology; Ethnic Groups*; Female; Homocysteine/blood*; Humans; India/ethnology; Malaysia; Malaysia/ethnology; Male; Middle Aged; Reference Values
  4. Takeuchi Y, Ichikawa S, Konuma A, Tomaru N, Niiyama K, Lee SL, et al.
    Heredity (Edinb), 2004 Apr;92(4):323-8.
    PMID: 14735142
    We investigated the fine-scale genetic structure of three tropical-rainforest trees, Hopea dryobalanoides, Shorea parvifolia and S. acuminata (Dipterocarpaceae), in Peninsular Malaysia, all of which cooccurred within a 6-ha plot in Pasoh Forest Reserve. A significant genetic structure was found in H. dryobalanoides, weaker (but still significant) genetic structure in S. parvifolia and nonsignificant structure in S. acuminata. Seeds of all three species are wind dispersed, and their flowers are thought to be insect pollinated. The most obvious difference among these species is their height: S. parvifolia and S. acuminata are canopy species, whereas H. dryobalanoides is a subcanopy species. Clear differences were also found among these species in their range of seed dispersal, which depends on the height of the release point; so taller trees disperse their seed more extensively. The estimates of seed dispersal area were consistent with the degree of genetic structure found in the three species. Therefore, tree height probably had a strong influence on the fine-scale genetic structure of the three species.
    MeSH terms: Demography; Seeds; Genetic Variation*; DNA, Plant/chemistry*; Microsatellite Repeats/genetics*; Theales/embryology; Theales/genetics*
  5. Reddy SC, Jackson N
    Acta Ophthalmol Scand, 2004 Feb;82(1):81-5.
    PMID: 14738490
    PURPOSE: To determine the prevalence of retinal changes in newly diagnosed acute leukaemia patients, and to establish the relationship between retinal lesions and haematological parameters in these patients.

    METHODS: A total of 127 patients with acute leukaemia (myeloid and lymphoid), of both genders, aged between 13 and 77 years, were examined by an ophthalmologist for retinal changes using direct/indirect ophthalmoscopy within 2 days of diagnosis before starting chemotherapy.

    RESULTS: Retinal lesions were seen in 62 cases (49%), with intraretinal haemorrhages being the most common lesion (42%). A high white blood cell count was significantly associated with intraretinal haemorrhages (p = 0.04) and white-centred haemorrhages (p = 0.001), while a low platelet count was significantly associated with intraretinal haemorrhages (p = 0.03) in acute myeloid leukaemia patients.

    CONCLUSIONS: A high white blood cell count may be considered as important as a low platelet count in the pathogenesis of leukaemic retinopathy.

    MeSH terms: Acute Disease; Adolescent; Adult; Aged; Antineoplastic Agents/therapeutic use; Female; Humans; Leukemia, Myeloid/blood; Leukemia, Myeloid/diagnosis*; Leukemia, Myeloid/drug therapy; Leukocyte Count; Male; Middle Aged; Ophthalmoscopy; Platelet Count; Prospective Studies; Retina/pathology*; Retinal Hemorrhage/diagnosis*; Retinal Neoplasms/blood; Retinal Neoplasms/diagnosis*; Retinal Neoplasms/drug therapy; Precursor Cell Lymphoblastic Leukemia-Lymphoma/blood; Precursor Cell Lymphoblastic Leukemia-Lymphoma/diagnosis*; Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy
  6. Tan DY, Hair Bejo M, Aini I, Omar AR, Goh YM
    Virus Genes, 2004 Jan;28(1):41-53.
    PMID: 14739650
    Base usage and dinucleotide frequency have been extensively studied in many eukaryotic organisms and bacteria, but not for viruses. In this paper, a comprehensive analysis of these aspects for infectious bursal disease virus (IBDV) was presented. The analysis of base usage indicated that all of the IBDV genes possess equivalent overall nucleotide distributions. However when the base usage at each codon positions was analysed by using cluster analysis, the VP5 open reading frame (ORF) formed a different cluster isolated from the other genes. The unusual base usage of VP5 ORF may indicate that the gene was originated by the virus "overprinting strategy", a strategy in which virus may create novel gene by utilizing the unused reading frames of its existing genes. Meanwhile, the GC content of the IBDV genes and the chicken's coding sequences was comparable; suggesting the virus imitation of the host to increase its translational efficiency. The analysis of dinucleotide frequency indicated that IBDV genome had dinucleotide bias: the frequencies of CpG and TpA were lower and the TpG was higher than the expected. Classical methylation pathway, a process where CpG converted to TpG, may explain the significant correlation between the CpG deficiency and TpG abundance. "Principal component analysis of the dinucleotide frequencies" (DF-PCA) was used to analyse the overall dinucleotide frequencies of IBDV genome. DF-PCA on the hypervariable region and polyprotein (VPX-VP4-VP3) gene showed that the very virulent IBDV (vvIBDV) was segregated from other strains; which meant vvIBDV had a unique dinucleotide pattern. In summary, the study of base usage and dinucleotide frequency had unravelled many overlooked genomic properties of the virus.
    MeSH terms: Animals; Infectious bursal disease virus/genetics*; Poultry/virology; Poultry Diseases/virology; Sequence Analysis, DNA
  7. Zaharias G, Piterman L, Liddell M
    Acad Med, 2004 Feb;79(2):148-55.
    PMID: 14744716
    BACKGROUND: Much research on gender differences in medicine has centered on women as better communicators, more egalitarian, more patient-centered, and more involved with psychosocial problems, preventive care, and female-specific problems. Hardly any research has examined the interaction between the doctor's gender and the patient's gender. The authors examined students' perceptions and comfort levels regarding patients' gender during consultation.

    METHOD: This cross-sectional study used a questionnaire to survey final-year medical students at one school in 1999. It tested students' patient-centeredness, "patient-care" values, and degree of comfort in performing certain intimate physical examinations.

    RESULTS: Women students were more patient-centered than were men students. Both genders were more attuned to the concerns of patients of their own gender, were more comfortable with personal rather than sexual issues, and were more uncomfortable with performing more intimate examinations upon the opposite gender. Using comparable case studies, it was also shown that the female student-female patient dyad had significantly greater "patient-care" values than did the male student-male patient dyad.

    CONCLUSION: Medical students did not behave in a gender-neutral way in the consultation. There is a powerful interaction between a student's gender and a patient's gender. This warrants further investigation in the real clinical situation because it has implications on the outcomes of the consultation.

    MeSH terms: Altruism; Attitude of Health Personnel*; Cross-Sectional Studies; Female; Humans; Malaysia; Male; Men/psychology*; Physical Examination/psychology; Professional-Patient Relations*; Surveys and Questionnaires; Students, Medical/psychology*; Women/psychology*
  8. Leow TC, Rahman RN, Basri M, Salleh AB
    Biosci Biotechnol Biochem, 2004 Jan;68(1):96-103.
    PMID: 14745170
    A thermostable extracellular lipase of Geobacillus sp. strain T1 was cloned in a prokaryotic system. Sequence analysis revealed an open reading frame of 1,251 bp in length which codes for a polypeptide of 416 amino acid residues. The polypeptide was composed of a signal peptide (28 amino acids) and a mature protein of 388 amino acids. Instead of Gly, Ala was substituted as the first residue of the conserved pentapeptide Gly-X-Ser-X-Gly. Successful gene expression was obtained with pBAD, pRSET, pET, and pGEX as under the control of araBAD, T7, T7 lac, and tac promoters, respectively. Among them, pGEX had a specific activity of 30.19 Umg(-1) which corresponds to 2927.15 Ug(-1) of wet cells after optimization. The recombinant lipase had an optimum temperature and pH of 65 degrees C and pH 9, respectively. It was stable up to 65 degrees C at pH 7 and active over a wide pH range (pH 6-11). This study presents a rapid cloning and overexpression, aimed at improving the enzyme yield for successful industrial application.
    MeSH terms: Amino Acid Sequence; Bacillaceae/enzymology*; Bacillaceae/genetics; Base Sequence; Cloning, Molecular; Enzyme Stability; Glutathione Transferase/genetics; Glutathione Transferase/metabolism; Hydrogen-Ion Concentration; Lipase/genetics*; Lipase/metabolism*; Molecular Sequence Data; Promoter Regions, Genetic; Recombinant Fusion Proteins/genetics; Recombinant Fusion Proteins/metabolism; Gene Expression Regulation, Bacterial; Gene Expression Regulation, Enzymologic; Polymerase Chain Reaction; Conserved Sequence; Amino Acid Substitution
  9. Yang S, Tan TM, Wee A, Leow CK
    Cell Mol Life Sci, 2004 Jan;61(2):220-9.
    PMID: 14745500
    For many liver malignancies, major hepatectomy is the usual therapy. Although a normal liver has a tremendous capacity for regeneration, liver hepatectomy in humans is usually carried out on a diseased liver and, in such cases, liver regeneration takes place in a cirrhotic remnant. Mitochondrial function in cirrhotic livers shows a variety of changes compared to control livers. This study investigated how mitochondrial respiratory function and antioxidant capacity change following partial hepatectomy of cirrhotic livers, because liver regeneration requires greater energy demands and control of oxidative stress. Cirrhosis was induced in male Wistar-Furth rats by administration of thioacetamide. NADH-cytochrome c reductase activity, mitochondrial glutathione peroxidase activity and mitochondrial GSH levels were all significantly lowered in cirrhotic livers and in the cirrhotic remnants up to 72 h after 70% hepatectomy when compared to the corresponding controls. Lower respiratory control ratios with succinate as substrate were also observed from 6 to 48 h post-hepatectomy. At 24 h post-hepatectomy, higher levels of lipid peroxidation were observed. We conclude that, compared to the controls, cirrhotic livers have diminished oxidative phosphorylation capabilities due to changes in NADH and FADH(2)-linked respiration as well as impaired antioxidant defenses following partial hepatectomy. Both of these factors, if critical, could then impede liver regeneration.
    MeSH terms: Adenosine Triphosphatases/metabolism; Animals; Hepatectomy*; Liver/enzymology; Liver/metabolism*; Liver Cirrhosis/enzymology; Liver Cirrhosis/metabolism*; Male; Mitochondria/metabolism*; Oxidation-Reduction*; Rats, Inbred WF; Time Factors; Rats
  10. Kong LL, Omar AR, Hair-Bejo M, Aini I, Seow HF
    Arch Virol, 2004 Feb;149(2):425-34.
    PMID: 14745606
    The deduced amino acid sequences of segment A and B of two very virulent Infectious bursal disease virus (vvIBDV) isolates, UPM94/273 and UPM97/61 were compared with 25 other IBDV strains. Twenty amino acid residues (8 in VP1, 5 in VP2, 2 in VP3, 4 in VP4, 1 in VP5) that were common to vvIBDV strains were detected. However, UPM94/273 is an exceptional vvIBDV with usual amino acid substitutions. The differences in the divergence of segment A and B indicated that the vvIBDV strains may have been derived from genetic reassortment of a single ancestral virus or both segments have different ability to undergo genetic variation due to their different functional constraints.
    MeSH terms: Amino Acid Sequence; Animals; Chickens/virology; Infectious bursal disease virus/classification; Infectious bursal disease virus/genetics*; Infectious bursal disease virus/pathogenicity*; Molecular Sequence Data; Phylogeny; Genetic Variation/genetics; Virulence/genetics; Viral Structural Proteins/genetics; Viral Structural Proteins/chemistry; Open Reading Frames/genetics; Genome, Viral*; Sequence Analysis, DNA; Mutation, Missense/genetics
  11. Ip YK, Randall DJ, Kok TK, Barzaghi C, Wright PA, Ballantyne JS, et al.
    J Exp Biol, 2004 Feb;207(Pt 5):787-801.
    PMID: 14747411
    Periophthalmodon schlosseri is an amphibious and obligatory air-breathing teleost, which is extremely tolerant to environmental ammonia. It actively excretes NH(4)(+) in ammonia loading conditions. For such a mechanism to operate efficaciously the fish must be able to prevent back flux of NH(3). P. schlosseri could lower the pH of 50 volumes (w/v) of 50% seawater in an artificial burrow from pH 8.2 to pH 7.4 in 1 day, and established an ambient ammonia concentration of 10 mmol l(-1) in 8 days. It could alter the rate of titratable acid efflux in response to ambient pH. The rate of net acid efflux (H(+) excretion) in P. schlosseri was pH-dependent, increasing in the order pH 6.0<7.0<8.0<8.5. Net acid flux in neutral or alkaline pH conditions was partially inhibited by bafilomycin, indicating the possible involvement of a V-type H(+)-ATPase. P. schlosseri could also increase the rate of H(+) excretion in response to the presence of ammonia in a neutral (pH 7.0) external medium. Increased H(+) excretion in P. schlosseri occurred in the head region where active excretion of NH(4)(+) took place. This would result in high concentrations of H(+) in the boundary water layer and prevent the dissociation of NH(4)(+), thus preventing a back flux of NH(3) through the branchial epithelia. P. schlosseri probably developed such an 'environmental ammonia detoxification' capability because of its unique behavior of burrow building in the mudflats and living therein in a limited volume of water. In addition, the skin of P. schlosseri had low permeability to NH(3). Using an Ussing-type apparatus with 10 mmol l(-1) NH(4)Cl and a 1 unit pH gradient (pH 8.0 to 7.0), the skin supported only a very small flux of NH(3) (0.0095 micromol cm(-2) min(-1)). Cholesterol content (4.5 micromol g(-1)) in the skin was high, which suggests low membrane fluidity. Phosphatidylcholine, which has a stabilizing effect on membranes, constituted almost 50% of the skin phospholipids, with phosphatidyleserine and phsophatidylethanolamine contributing only 13% and 15%, respectively. More importantly, P. schlosseri increased the cholesterol level (to 5.5 micromol g(-1)) and altered the fatty acid composition (increased total saturated fatty acid content) in its skin lipid after exposure to ammonia (30 mmol l(-1) at pH 7.0) for 6 days. These changes might lead to an even lower permeability to NH(3) in the skin, and reduced back diffusion of the actively excreted NH(4)(+) as NH(3) or the net influx of exogenous NH(3), under such conditions.
    MeSH terms: Acids/metabolism*; Ammonia/metabolism*; Animals; Biological Transport, Active; Environment*; Fatty Acids/analysis; Hydrogen-Ion Concentration; Malaysia; Perciformes/metabolism*; Phosphatidylcholines/analysis; Seawater/analysis*; Skin/metabolism; Skin/chemistry*
  12. Romaino SM, Teh LK, Zilfalil BA, Thong CP, Ismail AA, Amir J, et al.
    J Clin Pharm Ther, 2004 Feb;29(1):47-52.
    PMID: 14748897 DOI: 10.1046/j.1365-2710.2003.00535.x
    Polymorphism of the beta2-adrenergic receptor (beta2 AR) gene is an important determinant of the function of this receptor. It affects receptor down-regulation and beta2-agonist responses. It has also been a focus of interest in attempts to elucidate the genetic basis of asthma, hypertension, obesity and cystic fibrosis. Several different techniques have been established to determine beta2 AR genotypes but none of these methods are simple enough to detect simultaneously all the five alleles of our research interest (Arg16/Gly16, -20T/C, Gln27/Glu27, -47T/C and Thr164/Ile164).
    MeSH terms: Alleles; Genotype; Humans; Polymorphism, Genetic/genetics; Polymerase Chain Reaction/methods; Receptors, Adrenergic, beta-2/genetics*
  13. Todd AL, Ng WY, Lui KF, Thai AC
    Intern Med J, 2004 Jan-Feb;34(1-2):24-30.
    PMID: 14748910 DOI: 10.1111/j.1444-0903.2004.00482.x
    BACKGROUND: Circulating antibodies to glutamic acid decarboxylase (GADab) and tyrosine phosphatase-like molecule IA-2 (IA-2ab) are major indicators for auto-immune destruction of pancreatic islet cells. They identify a majority of Caucasians with type 1 diabetes and approximately 50% of Asians, providing evidence of an idiopathic aetiology in the latter. The present study investigated these autoantibodies in a mixed ethnic group.
    METHODS: Hospital clinic patients with clinically defined type 1 (n = 93) and type 2 (n = 300) diabetes and representing Singapore's major ethnic groups--Chinese, Indians and Malays--were studied. GADab and IA-2ab frequencies, and association of autoimmunity status with clinical and biochemical profiles were analysed.
    RESULTS: Radio-immunoprecipitation assays detected either or both antibodies (seropositivity) in 41.9% of subjects with type 1 diabetes. GADab was detected in 36.6% and IA-2ab in 23.7% of type 1 diabetics. Prevalence of IA-2ab showed a reduction in frequency with disease duration (P = 0.026). In clinical type 2 diabetics, seropositivity was 10.0% with higher frequency in Malays (17.5%) than Chinese (9.7%) and Indians (4.5%). Multivariate analysis revealed that low fasting C-peptide was associated with seropositivity (odds ratio (OR) = 0.15; 95% confidence interval (CI) = 0.04-0.58). A significant relationship (OR = 13.5; 95% CI = 5.0-36.7) between insulin requirement and duration (>5 years) was also revealed. In patients with type 2 diabetes there was a trend of gradual progression to insulin dependency. However, there was considerable variation in body mass index between ethnic subgroups of type 2 diabetics, particularly for Chinese (mean (SD) = 26.0 (4.7)) and Malays (mean (SD) = 29.2 (5.9); P < 0.001).
    CONCLUSIONS: Presence of both antibodies in our mixed ethnic group of type 1 diabetes patients was much lower than in Caucasians. Significant numbers of patients were seronegative for antibodies. Influences due to ethnicity and adiposity would require further investigations.
    MeSH terms: Adult; Autoantibodies/blood*; C-Peptide/blood; China/ethnology; Diabetes Mellitus, Type 1/immunology*; Diabetes Mellitus, Type 2/immunology; Female; Glutamate Decarboxylase/immunology*; Humans; India/ethnology; Insulin/administration & dosage; Malaysia/ethnology; Male; Radioimmunoassay; Singapore; Biomarkers/blood*; Body Mass Index; Prevalence; European Continental Ancestry Group; Asian Continental Ancestry Group
  14. William JL, Radu S, Aziz SA, Rahim RA, Cheah YK, Liwan A, et al.
    Br J Sports Med, 2004 Feb;38(1):12-4.
    PMID: 14751938
    BACKGROUND: Research has shown that athletes are carriers of Staphylococcus aureus during physical activity.
    OBJECTIVE: To estimate the mean total plate count of S aureus carried by footballers before and after training at an indoor venue.
    METHODS: Forty Malay and 20 Indian students volunteered to participate. There was also a control group consisting of 40 Malay and 20 Indian students who were not active. The experimental group were active footballers who had played at school or club level. The subjects were healthy and free of skin infection. The experiment was divided into three sessions, with 20 subjects present at each. At each session, the subjects trained for one hour. Swabs were taken from the skin, nose, and ear before and after training. For the control group, swabs were taken only once from the skin, nose, and ear. The swabs were subjected to biochemical tests and then streaked and cultured aerobically in Baird Parker agar plates for 24 hours at 37 degrees C. Black colonies with a clear zone were presumed to be S aureus, and the mean total plate count of the colonies was estimated. Gram staining, catalase, coagulase slide, coagulase tube, acetoin production, o-nitrophenyl beta-D-galactopyranoside (ONPG), and mannitol fermentation tests were used to confirm the colonies as S aureus. A haemolysin test was conducted with human blood to confirm haemolytic activity.
    RESULTS: All subjects in the experimental group were carrying S aureus both before and after training. The estimated mean total counts of colonies from the skin, ear, and nose for the Malays before training were 33, 71, and 312 respectively. Counts after training were 21, 44, and 452 respectively. The results for the Indians were 72, 80, and 309 respectively before training and 55, 200, and 466 respectively after training. The positive results for Gram staining, catalase, coagulase slide, coagulase tube, acetoin production, ONPG, and mannitol fermentation tests were 100%, 96%, 95%, 95%, 93%, 93%, and 90% respectively. All subjects in the control group were also carrying S aureus.
    CONCLUSIONS: All of the players were carriers of S aureus during training. The decrease in total count from the skin for both races may be due to lysozyme activity lysing the bacterial cells. Contamination of the environment with these bacteria may have increased the estimated total plate count in the nose. The experimental group face a higher risk of infection because of lower immunity during training and higher rate of injuries compared with the control group.
    MeSH terms: Adolescent; Carrier State/microbiology*; Disease Susceptibility; Ear/microbiology; Humans; Male; Nose/microbiology; Skin/microbiology; Soccer*; Staphylococcal Infections/microbiology*; Staphylococcus aureus/isolation & purification
  15. Khan N
    Appl Opt, 2004 Jan 20;43(3):678-81.
    PMID: 14765930
    The theoretical basis for simultaneous oscillation of 2N - 3 laser lines is due to interference of N (for all even N > or = 2) pump beams in a distributed-feedback dye laser is described. Multiple gratings are produced in a dye solution by interference patterns of N/2 pairs of a frequency-doubled Nd:YAG laser. N/2 pairs of mutually time-delayed pulses induce multiple gratings of different periodicities, of which 2N - 3 gratings support oscillation of 2N - 3 lines and the remaining gratings, because of their larger periods, cannot support Bragg scattering. The maximum number of laser lines depends on the mutual delay between adjacent pairs of beams, coherence, states of polarization, pulse lengths, and of course the number of pulses. For three pairs of excitation beams derived from the same source through wave-front or amplitude phase division techniques, the output lasing lines varied from a minimum of three to a maximum of nine. This research was carried out by pumping of a dye solution with two, four, and six pulses, but the principle may be extended to multiple output lines, depending on the number of pump pulses and on the gain of the dye solution.
    MeSH terms: Feedback; Radiation; Lasers, Solid-State; Lasers, Dye; Physical Phenomena
  16. Najafpour G, Younesi H, Syahidah Ku Ismail K
    Bioresour Technol, 2004 May;92(3):251-60.
    PMID: 14766158
    Fermentation of sugar by Saccharomyces cerevisiae, for production of ethanol in an immobilized cell reactor (ICR) was successfully carried out to improve the performance of the fermentation process. The fermentation set-up was comprised of a column packed with beads of immobilized cells. The immobilization of S. cerevisiae was simply performed by the enriched cells cultured media harvested at exponential growth phase. The fixed cell loaded ICR was carried out at initial stage of operation and the cell was entrapped by calcium alginate. The production of ethanol was steady after 24 h of operation. The concentration of ethanol was affected by the media flow rates and residence time distribution from 2 to 7 h. In addition, batch fermentation was carried out with 50 g/l glucose concentration. Subsequently, the ethanol productions and the reactor productivities of batch fermentation and immobilized cells were compared. In batch fermentation, sugar consumption and ethanol production obtained were 99.6% and 12.5% v/v after 27 h while in the ICR, 88.2% and 16.7% v/v were obtained with 6 h retention time. Nearly 5% ethanol production was achieved with high glucose concentration (150 g/l) at 6 h retention time. A yield of 38% was obtained with 150 g/l glucose. The yield was improved approximately 27% on ICR and a 24 h fermentation time was reduced to 7 h. The cell growth rate was based on the Monod rate equation. The kinetic constants (K(s) and mu(m)) of batch fermentation were 2.3 g/l and 0.35 g/lh, respectively. The maximum yield of biomass on substrate (Y(X-S)) and the maximum yield of product on substrate (Y(P-S)) in batch fermentations were 50.8% and 31.2% respectively. Productivity of the ICR were 1.3, 2.3, and 2.8 g/lh for 25, 35, 50 g/l of glucose concentration, respectively. The productivity of ethanol in batch fermentation with 50 g/l glucose was calculated as 0.29 g/lh. Maximum production of ethanol in ICR when compared to batch reactor has shown to increase approximately 10-fold. The performance of the two reactors was compared and a respective rate model was proposed. The present research has shown that high sugar concentration (150 g/l) in the ICR column was successfully converted to ethanol. The achieved results in ICR with high substrate concentration are promising for scale up operation. The proposed model can be used to design a lager scale ICR column for production of high ethanol concentration.
    MeSH terms: Ethanol/metabolism*; Fermentation; Glucose/metabolism*; Kinetics; Microscopy, Electron, Scanning; Models, Biological; Saccharomyces cerevisiae/metabolism*; Saccharomyces cerevisiae/ultrastructure; Time Factors; Bioreactors*
  17. Ng PH, Mahdy Z, Nik NI
    J Obstet Gynaecol, 2004 Feb;24(2):188-9.
    PMID: 14766471
    MeSH terms: Adult; Female; Humans; Neoplasm Recurrence, Local/pathology*; Neoplasm Recurrence, Local/surgery; Peritoneal Neoplasms/secondary*; Peritoneal Neoplasms/surgery; Reoperation; Gynecologic Surgical Procedures/methods; Uterine Neoplasms/pathology*; Uterine Neoplasms/surgery; Leiomyomatosis/pathology*; Leiomyomatosis/surgery
  18. Mariappan P, Loong CW
    J Urol, 2004 Mar;171(3):1233.
    PMID: 14767310
    MeSH terms: Acute Disease; Urinary Bladder Calculi/complications*; Urinary Bladder Calculi/surgery*; Female; Humans; Intestinal Obstruction/etiology*; Intestinal Obstruction/surgery*; Middle Aged
  19. Sosroseno W, Herminajeng E, Bird PS, Seymour GJ
    Oral Microbiol. Immunol., 2004 Apr;19(2):65-70.
    PMID: 14871343
    The aim of this study was to determine nitric oxide (NO) production of a murine macrophage cell line (RAW 264.7 cells) when stimulated with Porphyromonas gingivalis lipopolysaccharides (Pg-LPS). RAW 264.7 cells were incubated with i) various concentrations of Pg-LPS or Salmonella typhosa LPS (St-LPS), ii) Pg-LPS with or without L-arginine and/or NG-monomethyl-L-arginine (NMMA), an arginine analog or iii) Pg-LPS and interferon-gamma (IFN-gamma) with or without anti-IFN-gamma antibodies or interleukin-10 (IL-10). Tissue culture supernatants were assayed for NO levels after 24 h in culture. NO was not observed in tissue culture supernatants of RAW 264.7 cells following stimulation with Pg-LPS, but was observed after stimulation with St-LPS. Exogenous L-arginine restored the ability of Pg-LPS to induce NO production; however, the increase in NO levels of cells stimulated with Pg-LPS with exogenous L-arginine was abolished by NMMA. IFN-gamma induced independent NO production by Pg-LPS-stimulated macrophages and this stimulatory effect of IFN-gamma could be completely suppressed by anti-IFN-gamma antibodies and IL-10. These results suggest that Pg-LPS is able to stimulate NO production in the RAW 264.7 macrophage cell model in an L-arginine-dependent mechanism which is itself independent of the action of IFN-gamma.
    MeSH terms: Analysis of Variance; Animals; Antibodies/immunology; Arginine/pharmacology*; Cell Line; Enzyme Inhibitors/pharmacology; Interferon-gamma/immunology; Interferon-gamma/pharmacology; Lipopolysaccharides/pharmacology*; Macrophages/drug effects*; Macrophages/immunology; Nitric Oxide/biosynthesis*; Salmonella typhi; Time Factors; Interleukin-10/pharmacology; Porphyromonas gingivalis*; Nitric Oxide Synthase/antagonists & inhibitors; omega-N-Methylarginine/pharmacology; Mice
  20. Ng KK, Lee SL, Koh CL
    Mol Ecol, 2004 Mar;13(3):657-69.
    PMID: 14871369
    Analyses of the spatial distribution pattern, spatial genetic structure and of genetic diversity were carried out in two tropical tree species with contrasting breeding systems and different ploidy levels using a 50-ha demographic plot in a lowland dipterocarp forest in Peninsular Malaysia. Shorea leprosula is a diploid and predominantly outcrossed species, whereas S. ovalis ssp. sericea is an autotetraploid species with apomictic mode of reproduction. Genetic diversity parameters estimated for S. leprosula using microsatellite were consistently higher than using allozyme. In comparisons with S. leprosula and other tropical tree species, S. ovalis ssp. sericea also displayed relatively high levels of genetic diversity. This might be explained by the lower pressure of genetic drift due to tetrasomic inheritance, and for autotetraploids each locus can accommodate up to four different alleles and this allows maintenance of more alleles at individual loci. The observed high levels of genetic diversity in S. ovalis ssp. sericea can also be due to a random retention of more heterogeneous individuals in the past, and the apomictic mode of reproduction might be an evolutionary strategy, which allows the species to maintain high levels of genetic diversity. The spatial distribution pattern analyses of both species showed significant levels of aggregation at small and medium but random distribution at the big diameter-class. The decrease in magnitude of spatial aggregation from small- to large-diameter classes might be due to compensatory mortality during recruitment and survival under competitive thinning process. Spatial genetic structure analyses for both species revealed significant spatial genetic structure for short distances in all the three diameter-classes. The magnitude of spatial genetic structure in both species was observed to be decreasing from smaller- to larger-diameter classes. The high spatial genetic structuring observed in S. ovalis ssp. sericea at the small-diameter class is due primarily to limited seed dispersal and apomictic mode of reproduction. The similar observation in S. leprosula, however, can be explained by limited seed and pollen dispersal, which supports further the fact that the species is pollinated by weak fliers, mainly of Thrips and Megalurothrips in the lowland dipterocarp forest.
    MeSH terms: Age Factors; Demography*; Gene Frequency; Genetics, Population*; Isoenzymes; Malaysia; Ploidies; Reproduction/physiology; Trees*; Tropical Climate; Genetic Variation*; Microsatellite Repeats/genetics; Theales/genetics*; Theales/physiology
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