Published by Science Society of Thailand

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On an argument of J.--F. Cardoso dealing with perturbations of joint diagonalizers
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March 2011


56 Reads

B. Afsari has recently proposed a new approach to the matrix joint diagonalization, introduced by J.--F. Cardoso in 1994, in order to investigate the independent component analysis and the blind signal processing in a wider prospective. Delicate notions of linear algebra and differential geometry are involved in the works of B. Afsari and the present paper continues such a line of research, focusing on a theoretical condition which has significant consequences in the numerical applications.

Operator Connections and Borel Measures on the Unit Interval

November 2012


117 Reads

A connection is a binary operation for positive operators satisfying the monotonicity, the transformer inequality and the joint-continuity from above. A mean is a normalized connection. In this paper, we show that there is a one-to-one correspondence between connections and finite Borel measures on the unit interval via a suitable integral representation. Every mean can be regarded as an average of weighted harmonic means. Moreover, we investigate decompositions of connections, means, symmetric connections and symmetric means.

Probabilistic pointer analysis for multithreaded programs

December 2011


44 Reads

The use of pointers and data-structures based on pointers results in circular memory references that are interpreted by a vital compiler analysis, namely pointer analysis. For a pair of memory references at a program point, a typical pointer analysis specifies if the points-to relation between them may exist, definitely does not exist, or definitely exists. The "may be" case, which describes the points-to relation for most of the pairs, cannot be dealt with by most compiler optimizations. This is so to guarantee the soundness of these optimizations. However, the "may be" case can be capitalized by the modern class of speculative optimizations if the probability that two memory references alias can be measured. Focusing on multithreading, a prevailing technique of programming, this paper presents a new flow-sensitive technique for probabilistic pointer analysis of multithreaded programs. The proposed technique has the form of a type system and calculates the probability of every points-to relation at each program point. The key to our approach is to calculate the points-to information via a post-type derivation. The use of type systems has the advantage of associating each analysis results with a justification (proof) for the correctness of the results. This justification has the form of a type derivation and is very much required in applications like certified code.

Fig 1. Schematic representation of β-cyclodextrin, (A) a cyclic oligosaccharide (top view) (B) the 1→4-linked α-D-glucopyranosyl unit and (C) a truncated torus shape (side view).  
Fig 2. (A) 1 H NMR spectra as a function of molar ratios of β-CD/L-Phe ranging from 1:0 (#1) to 1:6.7 (#13). 1 H Peaks in each region (a-e) are as follows: aromatic L-Phe (a), H1 (b), H3, H5, H6 and Hα (c), H2 and H4 (d), and Hβ (e). (B) An enlargement of selected regions demonstrating shifted peaks for H3, H5 and H6 protons (c) but H2 and H4 relatively unchanged (d). Protons are labeled according to the commonly used standard.  
Fig 4. The predicted ensembles of the two possible arrangements of L-Phe in the β-CD cavity: (A) the aromatic sidechains of L-Phe near the outer mouth of β-CD with p=0.41; (B) opposite orientation relative to (A) with p =0.34.  
An Inclusion Complex of β-Cyclodextrin-LPhenylalanine: 1H NMR and Molecular Docking Studies

September 2003


881 Reads

An inclusion host-guest complex between β-cyclodextrin (β-CD) and L-phenylalanine (LPhe) was investigated using 1H nuclear magnetic resonance spectroscopy and molecular docking techniques. 1H chemical shift changes of β-CD were used to calculate the stability constant (Kstb) of the complex. On the basis of the Hildebrand-Benesi method, the Kstb of the 1:1 complex in D2O solution at 300 K, pD 7.6 was of 25.5 M-1, implying a fast intermolecular exchange rate process. Interestingly, docking simulation indicates the toroidal space can be occupied by L-Phe with two favorable arrangements. For the predicted model with the higher probability score, the L-Phe aromatic ring is facing to the secondary hydroxyl groups of β-CD. Results from NMR and docking simulation are in good agreement with the x-ray structures of β-CD/L-phenylalanine derivatives.

Immobilization of a Thermostable Alpha-Amylase

September 2003


119 Reads

Cellulose fibers from bagasse were oxidized by periodic acid at positions 2 and 3 of the anhydroglucose unit to obtain dialdehyde cellulose. The aldehyde groups of the dialdehyde cellulose were able to react with amino groups of a thermostable alpha-amylase to form covalent bonds and resulted in a dialdehyde cellulose immobilized enzyme. The optimum pH of this immobilized enzyme was pH 7-9 while that of the free enzyme was pH 7.0. The optimum temperature for free and immobilized enzymes was 90 C and 95 C, respectively. The activity yield of the immobilized enzyme was 44% .

Molecular Cloning and Sequencing of a cDNA Encoding 3-Hydroxy-3-Methylglutaryl Coenzyme A Synthase from Hevea brasiliensis (HBK ) Mull Arg

September 2003


68 Reads

A 1.8 kb cDNA clone encoding 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) synthase was isolated from a cDNA library prepared from the C-serum of rubber latex from Hevea brasiliensis (H.B.K.) Mull. Arg. using an Arabidopsis thaliana cDNA encoding HMG-CoA synthase as a probe. The nucleotide sequence analysis revealed an open reading frame of 1,392 nucleotides which encoded a protein of 464 amino acids with a predicted molecular mass of 51.28 kDa. The deduced amino acid sequence exhibits strong similarities with plant and mammalian HMG-CoA synthase sequences. Analysis of RNA samples from different tissues of rubber tree seedlings showed a higher mRNA level in stem and petiole than in leaves. In mature rubber trees there were higher mRNA levels in latex and petiole than in leaves. This suggests that the expression of the HMG-CoA synthase gene is higher in laticifer cells than in leaves. Genomic Southern blot analysis using the full-length cDNA as a probe indicates the presence of up to three HMG-CoA synthase genes in Hevea brasiliensis.

Automatic exudate detection for diabetic retinopathy screening

March 2009


185 Reads

Exudates are one of the primary signs of diabetic retinopathy which is a main cause of blindness that could be prevented with an early screening process. Pupil dilation is required in the normal screening process but this affects patients' vision. Automatic computerized screening could facilitate the screening process, reduce inspection time, and increase accuracy. In this paper we propose an automatic method to detect exudates from low-contrast digital images of retinopathy patients with non-dilated pupils using a fuzzy c-means (FCM) clustering technique. Preprocessing of contrast enhancement was applied in order to enhance the quality of the input image before four features, namely, intensity, standard deviation on intensity, hue, and number of edge pixels, were selected to supply to the FCM method. The number of required clusters was optimally selected from a quantitative experiment where it was varied from two to eight clusters. The number of cluster optimization was based on sensitivity and specificity which were calculated by comparison of the detected results and hand-drawn ground truths from expert ophthalmologists. The positive predictive value and positive likelihood ratio were also used to evaluate the overall performance of this method. From the result of the subtracted cluster with the number of clusters equalling 2, it was found that the proposed method detected exudates with 92.18% sensitivity and 91.52% sensitivity.

Fig. 1 XRD patterns of (1 − x) NKLNT-x MnO ceramics sintered at 1025 °C.
Fig. 2 Density values of (1 − x) NKLNT-x MnO when reaction-sintered at different temperatures.
Fig. 3 SEM micrographs (1 − x ) NKLNT– x MnO samples where x corresponds to: (a) 0 mol%, (b) 0.5 mol%, and (c) 1.0 mol% sintered at 1025 °C for 2 h. 
Structural and electrical properties of (1 - X) Na0.465K 0.465Li0.07Nb0.93Ta0.07O 3-x MnO lead-free piezoelectric ceramics synthesized at low sintering temperatures

September 2010


49 Reads

Ceramics of the lead-free piezoelectric ceramic composition, Na 0.465K0.465Li0.07Nb0.93Ta 0.07O3, (NKLNT), were prepared using a reaction sintering method. The effects of manganese oxide doping on the structural and electrical properties of NKLNT ceramics were investigated. Variations in the relative intensity of X-ray diffraction peaks were consistent with Mn ions substituting on the perovskite lattice to produce a change in the proportions of co-existing tetragonal and orthorhombic phases. Grain growth during secondary recrystallization was also affected, leading to more uniform microstructures. The temperature of the orthorhombic-tetragonal (O-T) phase transition decreased, and the Curie temperature increased as a result of Mn modifications. The dielectric dissipation factors were lowered by Mh incorporation, but the d 33 piezoelectric charge coefficient fell from 190 pC/N to ≤ 144 pC/N due to the shift in the O-T phase transition to well below room-temperature.

Table 1 Comparison of typical reported properties of NKN-LT-LS compositions.
Fig. 3 DSC results of NKN-LT-LS samples.
Fig. 4 Effect of NKN-LT-LS sample temperature on (a) dielectric constant (b) dissipation factor.
Fig. 5 Curie (peak) temperature from DSC analysis and dielectric constant measurement for NKN-LT-LS samples.
Phase transition behaviour and dielectric properties of Na 0.5K0.5NbO3-LiTaO3-LiSbO 3 Lead-free piezoceramic

September 2009


323 Reads

Lead-free piezoelectric ceramics have attracted considerable attention as new piezoelectric materials for replacing Pb(Zr,Ti)O3 (PZT)-based ceramics because of environmental protection reasons. Among lead-free piezoelectric systems, the ternary system of Na0.5K 0.5NbO3-LiTaO3-LiSbO3 has proven to be an outstanding lead-free piezoceramic with properties almost comparable to undoped PZT. In this study, addition of LiSbO3 to the 0.95Na 0.5K0.5NbO3-0.05 LiTaO3 lead-free piezoceramic composition showed a change from an orthorhombic to a tetragonal crystal system in samples prepared by reaction-sintering. The limit of solid solution along the compositional join, (0.95-x)Na0.5K 0.5NbO3-0.05LiTaO3-x LiSbO3, occurred at x ∼ 0.06. Differential scanning calorimetry analysis and measurements of dielectric constant as a function of temperature indicated broad Curie peaks from which it was inferred that the samples were not chemically homogeneous. Curie temperatures decreased from ∼425 °C for x = 0, to ∼345 °C for the limiting x = 0.06 composition. Improvement of dielectric properties was obtained for LiSbO3 modified samples. Microstructures exhibited secondary recrystallization, with LiSbO3 addition giving rise to a small reduction in average grain size.

Fig. 2 The individual structure in CGA. 
A combined compact genetic algorithm and local search method for optimizing the ARMA(1,1) model of a likelihood estimator

February 2014


111 Reads

In this paper, a compact genetic algorithm (CGA) is enhanced by integrating its selection strategy with a steepest descent algorithm (SDA) as a local search method to give I-CGA-SDA. This system is an attempt to avoid the large CPU time and computational complexity of the standard genetic algorithm. Here, CGA dramatically reduces the number of bits required to store the population and has a faster convergence. Consequently, this integrated system is used to optimize the maximum likelihood function lnL(φ1, θ1) of the mixed model. Simulation results based on MSE were compared with those obtained from the SDA and showed that the hybrid genetic algorithm (HGA) and I-CGA-SDA can give a good estimator of (φ1, θ1) for the ARMA(1,1) model. Another comparison has been conducted to show that the I-CGA-SDA has fewer function evaluations, minimum search space percentage, faster convergence speed and has a higher optimal precision than that of the HGA

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Test of precision and accuracy of the proposed method.
Analytical study of charge transfer complexation of rabeprazole with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone

December 2009


55 Reads

A simple, sensitive spectrophotometric method was developed for the determination of rabeprazole sodium (RA) in pure form and for pharmaceutical formulations. The charge transfer interaction between RA and 2,3-dichloro-5,6dicyano-p-benzoquinone (DDQ) as an acceptor was investigated spectrophotometrically. Variables affecting the reaction were studied and optimized. The proposed method was applied successfully to the determination of RA in its pure form and pharmaceutical dosage forms with good accuracy and precision. The formation of charge transfer complex and the site of interaction was confirmed by using UV-Visible spectrophotometry, FT-IR spectrometry, and 1H NMR techniques. Based on Job's method of continuous variation plots, the obtained results indicate the formation of 1:1 charge transfer complex with a general formula [(RA) (DDQ)]. Statistical comparison of the results with the reference method shows excellent agreement and indicates no significant differences in accuracy or precision.

Antioxidant and anticancer effects of fermented Rhus verniciflua stem bark extracts in HCT-116 cells

October 2015


45 Reads

Rhus verniciflua bark has been used as a traditional medicine for the treatment of several diseases in Korea. In this study, the antioxidant properties and anticancer activity of a fermented R. verniciflua (F-RV) methanol extract and its fractions were determined. The methanol extract and the ethyl acetate fraction had high radical-scavenging and reducing-power activities, higher than that of butylated hydroxytoluene. Moreover, the antioxidant activity was correlated with the contents of the phenolic compounds. The cell viability assay showed that F-RV contains anticancer activity in a colon cancer cell line (HGT-116), and upregulates TGF-beta. Thus F-RV has an inhibitory effect on cell proliferation and can induce apoptosis and senescence. F-RV could be useful for the development of bioactive food and anticancer drugs.

Fig. 1 1.5% agarose gel electrophoresis of MMP-9 promoter PCR products (three different fragments). M is 100 bp ladder. 
Table 1 Baseline characteristics of participants.
Table 3 Multiple logistic regression analysis of interaction among the MMP-9 polymorphism and the risks of ACS.
Table 4 Serum MMP-9 concentrations by MMP-9 1562C>T genotypes and alleles. Subjects Serum MMP-9 concentrations (ng/ml) p value
Matrix metalloproteinase 9 gene polymorphism 1562C>T is significantly associated with acute coronary syndrome susceptibility in the Vietnamese population

October 2017


189 Reads

The role of the 1562C>T single nucleotide polymorphism of the matrix metalloproteinase 9 (MMP-9) gene promoter in acute coronary syndrome (ACS) development has been reported in various populations. In this work, we investigated the association between MMP-9 1562C>T polymorphism and ACS patients in Vietnam. This study was conducted on 138 ACS patients and 68 control subjects recruited from the Vietnam National Heart Institute. The genotype of 1562C>T polymorphism was determined by RFLP-polymerase chain reaction and the serum MMP-9 level was measured by the ELISA method. We found that the frequencies of CT and TT genotypes in the ACS patients (30% and 4%) were higher than those in the control (18% and 1%). The 1562T allele in the MMP-9 promoter was found to have a significantly higher frequency in ACS patients than in control subjects (ACS versus control: 19% versus 10%, p = 0.001). Multiple logistic regression analysis indicated that the MMP-9 1562T allele carriers had an increased risk of developing ACS (odds ratio = 2.37; 95% confidence intervals: 1.04–5.75, p = 0.045). The serum MMP-9 level in the polymorphism-carrying group was considerably higher than in the group without polymorphism in both ACS patients (229 ± 83 versus 194 ± 108, p = 0.037) and controls (220 ± 41 versus 171 ± 80, p = 0.006). Our results showed that the MMP-9 1562C>T polymorphism is significantly associated with the ACS susceptibility in the Vietnamese population.

Alpha-diversity of the gut microbiota in fecal samples from the red deer (group ML) and fallow deer (group TL).
Comparison of the gut microbiome in red deer (Cervus elaphus) and fallow deer (Dama dama) by high-throughput sequencing of the V3-V4 region of the 16S rRNA gene

December 2019


491 Reads

The gut microbiome is a complex ecosystem that plays an essential role in maintaining the host’s gut homeostasis and health. The available sequencing data for the Cervidae gut microbiome, especially for red deer and fallow deer in China, are limited. To improve the health of the two species in captivity, we characterized the gut microbiome of red deer and fallow deer via high-throughput Illumina sequencing of the 16S rRNA genes V3–V4 hypervariable regions. We found that the gut microbiome community of red deer included 20 phyla, 89 families and 193 genera, while the gut microbiome community of fallow deer included 18 phyla, 102 families and 227 genera. Firmicutes (red deer: 37.46–44.98%; fallow deer: 32.67–49.54%) was the most abundant phylum, followed by Bacteroidetes (red deer: 28.09–39.02%; fallow deer: 27.45–38.71%). The observed species and Shannon indices in red deer were higher than in fallow deer (p = 0.002, 0.016, respectively). Hence compared with fallow deer, red deer had higher diversity and species richness in their gut microbiome. The MRPP results showed that significant differences did occur in their microbiome compositions (A = 0.037, significance level α = 0.001). This study provides an initial understanding of the gut microbiome composition of red deer and fallow deer. The results may benefit captive management and future reintroduction prog.

Filtration rates of the green-lipped mussel Perna viridis (Linnaeus, 1758) exposed to high concentration of suspended particles

January 2022


314 Reads

High suspended loading is one of the environmental stressors which could affect survival rates and feeding activities of marine bivalves, especially the coastal species. Therefore, this study aimed to examine the effects of suspended particles (SP) on filtration rates of the green-lipped mussel Perna viridis, which is a commercial bivalve species in Thai coastal waters. The large and small mussels were subjected to 250 mg and 500 mg of SP/l, and a control treatment (0 mg of SP/l) in the experimental laboratory. Filtration rates of the mussels were measured at day 0, day 15, and day 20 after the exposure to SP. The results showed that filtration rates of two class-sizes of the mussels significantly decreased after the exposure to SP for 15 and 20 days. Before the exposure to SP (day 0), the large mussels had significantly greater filtration rates than the smaller individuals, indicating the size-dependent effects. Filtration rates of the mussels decreased with increasing concentrations of SP. Gill abnormalities, e.g., loss of cilia on the gill lamella, were detected in the selected mussels at 500 mg of SP/l. The small mussels exhibited less capability in maintaining filtration rates compared with the larger mussels under high SP concentration. Moreover, changes in filtration rates over the exposure time were also discussed based on our study. Overall, the results can reflect deleterious effects of high SP on the mussels, particularly in filter-feeding activities. These findings could raise environmental concerns over high SP that could damage cultured mussels and coastal ecosystems.

Effects of 17β-estradiol on liver vitellogenin gene expression in immature female frogs, Hoplobatrachus rugulosus

December 2008


12 Reads

We aimed to determine the vitellogenin gene expression in response to 17β-estradiol (E2) treatment in livers of immature female Chinese edible frogs (Hoplobatrachus rugulosus). Frogs reared during rainy or dry seasons were intramuscularly injected daily with E2 at doses of 0, 50, 500, or 5000 μg/kg body weight for five days. During the rainy season, treatment with E2 within the dose range studied significantly decreased the vitellogenin gene transcript levels compared to those of the control. In contrast, during the dry season, treatment with E2 at all doses tended to increase the vitellogenin gene transcript levels. The endogenous plasma E2 levels in frogs reared during the rainy season were higher than those reared during the dry season. There was no significant difference in liver-somatic index or gonadosomatic index among the treated frogs during the rainy season. However, during the dry season, the 500 μg/kg E2 treatment significantly increased the frog liver-somatic index. The hepatocytes from the dry season frogs appeared smaller and flatter. The histology of ovaries from rainy season frogs showed that the oocytes were bigger and of several stages. We therefore concluded that the injection of E 2 into immature female H. rugulosus may stimulate vitellogenesis if administered during the dry season, when the endogenous E2 is lower. This knowledge could be used as a basis for inducing precocious maturation or mating of H. rugulosus outside the breeding season.

Fig. 1 
Table 1 Genotypic and allelic frequencies of 17β-HSD8 gene genetic polymorphism in KD patients and controls.
Table 2 Distribution of 17β-HSD8 gene haplotype frequen- cies in patients with KD and controls.
Table 3 Distribution of 17β-HSD8 haplotype frequencies in KD patients with/without coronary artery lesions (CAL).
Table 4 Association between 17β-HSD8 gene diplotypes a and clinical parameters in KD patients .
Association between 17β-HSD8 polymorphisms and Kawasaki disease among Han Chinese children in Taiwan

September 2011


42 Reads

Kawasaki disease (KD) is considered infectious, with immunologic expressions caused by genetic susceptibility of individuals. The 17 beta-hydroxysteroid dehydrogenase type 8 (17 beta-HSD8) enzymes are involved in the biosynthesis of oestrogens and androgens and regulate immune responses through hormonal modulation in mammals. To clarify the relationship between 17 beta-HSD8 gene single nucleotide polymorphisms (SNPs) and the pathogenesis of KD, we investigated association between 17 beta-HSD8 SNPs (rs421446, rs213213) and KD in Taiwanese children. Genotype analysis involved 93 KD patients and 680 unrelated healthy children. Our findings indicated the frequency of A allele in polymorphisms rs421446 was markedly higher among the patient group (43.3%) than in the control group (34.0%; p = 0.032). Children with the A allele at rs421446 SNP may show higher risk of developing KD, particularly those with AA homozygous genotype. From comparison of haplotype frequencies between case and control, children with AC haplotype appeared more "at-risk" for KD progression (p = 0.022). Our results suggest that rs421446 polymorphism and the haplotypes in 17 beta-HSD8 gene are associated with the risk of KD in Taiwanese children.

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