Publications by authors named "Ooi T"

In our previous study, a system for producing poly(3-hydroxybutyrate) [P(3HB)] was established by introducing a polyhydroxyalkanoate (PHA) biosynthetic gene operon (phaCAB Re) derived from Ralstonia eutropha into Corynebacterium glutamicum. In this study, two experimental strategies have been applied to improve P(3HB) production in recombinant C. glutamicum.

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New aliphatic sulfates and sulfamates were isolated from Daphnia pulex as the Daphnia kairomones that induced morphological defense of a freshwater phytoplankton Scenedesmus gutwinskii var. heterospina (NIES-802). Their structures were determined by spectroscopic and synthetic studies.

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4,8-Dimethylnonyl sulfate (1) and 3-methyl-4E-decenyl sulfate (2) were isolated from Daphnia pulex as the Daphnia kairomones that induced morphological defense of a freshwater phytoplankton Scenedesmus gutwinskii var. heterospina (NIES-802). The absolute configuration at C4 of 1 was determined by Ohrui's method applied to alcohol 3.

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A methanol extract of the wood of Cordia fragrantissima, collected in Burma (Myanmar), was found to exhibit significant activity against Leishmania major. Bioassay-guided fractionation of this extract using several chromatographic techniques afforded three new compounds (1-3) and five known compounds (4-8). The structures of the new compounds were revealed on the basis of spectroscopic data interpretation and by X-ray crystallographic analysis.

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Three new 14-membered macrolides, named aspergillides A, B, and C (1, 5, and 7), were isolated from marine-derived fungus Aspergillus ostianus strain 01F313, cultured in a medium composed of bromine-modified artificial seawater. The structures of the new compounds were determined by analyses of 1D and 2D NMR spectra. Their absolute configurations were elucidated by the modified Mosher's method and chemical conversions.

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Three new pentaketides, aspinotriols A ( 1) and B ( 3) and aspinonediol ( 5), were isolated together with two known compounds, aspinonene ( 7) and dihydroaspyrone ( 9), from the marine fungus Aspergillus ostianus strain 01F313, which was collected in Pohnpei and cultured with bromine-modified artificial seawater. The structures of the new compounds were determined by spectroscopic analyses including 1D and 2D NMR. Although 1 and 3 are diastereomers, they show nearly superimposable (1)H and (13)C NMR spectra.

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Most ground surfaces contain various types of texture gradient information that serve as depth cues for space perception. We investigated how linear perspective, a type of texture gradient information on the ground, affects judged absolute distance and eye level. Phosphorescent elements were used to display linear perspective information on the floor in an otherwise dark room.

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Resistance to thyroid hormone (RTH) is a rare, inherited condition. It is characterised by raised circulating fT4 and TSH levels. The literature contains a number of descriptions of the finding of thyroid autoantibodies in patients with RTH.

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Phase-transfer-catalyzed alkylation of glycinate Schiff base with racemic secondary alkyl halides proceeded with excellent levels of syn- and enantioselectivities under the influence of chiral quaternary ammonium bromide 1d and 18-crown-6. The alkylation product can be selectively converted to the corresponding anti isomer, allowing the preparation of all the stereoisomers of beta-alkyl-alpha-amino acid derivatives, an extremely valuable chiral building block.

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Proprotein convertase subtilisin kexin-like 9 (PCSK9) is a secreted glycoprotein that negatively regulates low density lipoprotein receptor (LDLR) levels. Several single nucleotide polymorphisms (SNPs) in PCSK9 have been linked to autosomal dominant hypercholesterolemia (ADH). Conversely, hypocholesterolemia associates with both 'loss of function' nonsense and missense SNPs in PCSK9.

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The sequential-surface-integration-process (SSIP) hypothesis was proposed to elucidate how the visual system constructs the ground-surface representation in the intermediate distance range (He et al, 2004 Perception 33 789-806). According to the hypothesis, the SSIP constructs an accurate representation of the near ground surface by using reliable near depth cues. The near ground representation then serves as a template for integrating the adjacent surface patch by using the texture gradient information as the predominant depth cue.

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The gene coding for an azoreductase, designated as an azrA, was cloned by polymerase chain reaction amplification from the genomic DNA of Bacillus sp. strain B29 isolated from soil. The azrA encoded a protein of 208 amino acids with calculated molecular mass of 22,766 Da.

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The use of chiral nonracemic onium salts and crown ethers as effective phase-transfer catalysts have been studied intensively primarily for enantioselective carbon-carbon or carbon-heteroatom bond-forming reactions under mild biphasic conditions. An essential issue for optimal asymmetric catalysis is the rational design of catalysts for targeted reaction, which allows generation of a well-defined chiral ion pair that reacts with electrophiles in a highly efficient and stereoselective manner. This concept, together with the synthetic versatility of phase-transfer catalysis, provides a reliable and general strategy for the practical asymmetric synthesis of highly valuable organic compounds.

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In her seminal article in Psychological Review, A. S. Gilinsky (1951) successfully described the relationship between physical distance (D) and perceived distance (d) with the equation d = DA/(A + D), where A = constant.

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A series of structurally rigid, chiral quaternary ammonium salts and several chiral sec-amine catalysts derived from commercially available (R)- or (S)-binaphthol have been designed as new C(2)-symmetric chiral phase-transfer catalysts and chiral bifunctional amino-catalysts. These chiral organocatalysts have been successfully applied to the highly practical asymmetric synthesis of various amino acid derivatives.

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A biosynthetic pathway for poly(3-hydroxybutyrate) [P(3HB)] production by Corynebacterium glutamicum was developed by introducing the phbCAB operon derived from Ralstonia eutropha. P(3HB) synthase activity was detected in this recombinant C. glutamicum carrying a cell surface protein gene promoter.

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Article Synopsis
  • Two patients with type 2 diabetes experienced significantly low HDL-C levels while undergoing treatment with rosiglitazone, with one seeing a drop from 33 to 11.6 mg/dL and the other from 44.8 to 19.7 mg/dL.
  • Both patients had their low HDL-C levels resolve after stopping rosiglitazone and showed no such changes when treated with pioglitazone, indicating a specific association with rosiglitazone therapy.
  • It is suggested that monitoring of lipid levels should be conducted for patients on rosiglitazone since paradoxical decreases in HDL-C have been reported, further supporting the need to assess lipid changes regularly during long-term treatment.
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Correct judgment of egocentric/absolute distance in the intermediate distance range requires both the angular declination below the horizon and ground-surface information being represented accurately. This requirement can be met in the light environment but not in the dark, where the ground surface is invisible and hence cannot be represented accurately. We previously showed that a target in the dark is judged at the intersection of the projection line from the eye to the target that defines the angular declination below the horizon and an implicit surface.

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Theoretical and empirical studies show that the visual system relies on boundary contours and surface features (e.g. textures) to represent 3-D surfaces.

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[reaction: see text] Treatment of sarcophytoxide with trimethylsilyl trifluoromethanesulfonate afforded an aromatic ketone as an unusual cyclization product. The modified Mosher's method and X-ray analysis performed on the aromatic ketone revealed that it is a 4:1 mixture of 8(R)- and 8(S)-enantiomers. It also suggested that the precursor ketone has 8(R)-configuration, which is contradictory to that expected from the ordinary epoxide-ketone rearrangement.

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Epidermal melanin reduces some effects of UV radiation, the major cause of skin cancer. To examine whether induced melanin can provide protection from sunburn injury, 65 subjects completed a trial with the potent synthetic melanotropin, [Nle4-D-Phe7]-alpha-melanocyte-stimulating hormone ([Nle4-D-Phe7]-alpha-MSH) delivered by subcutaneous injection into the abdomen at 0.16 mg/kg for three 10-day cycles over 3 months.

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We developed a fabrication method and a liquid filling method for a nano chemical reactor that used Y-shaped nanochannels specially designed for mixing and reacting. In order to reduce the pressure loss and to utilize the characteristics of the nanochannel, inlet microchannels were fabricated just beside the nanochannels. We investigated an initial liquid filling method into the nanochannels that ensured there were no air bubbles that could cause a flow stack due to the capillary pressure.

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