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Biomedical subjects

T H Kim

Publications and source records attributed to T H Kim.

At least 37 records · Page 2Linked to original sources
PubMed2004

Measurement of the CP asymmetry in B-->Xs gamma.

Direct CP violation in the b-->sgamma process is a sensitive probe of physics beyond the standard model. We report a measurement of the CP asymmetry in B-->X(s)gamma, where the hadronic recoil system X(s) is reconstructed using a pseudoreconstruction technique. In this approach there is negligible contamination from b-->dgamma decays, which are expected to have a much larger CP asymmetry. We find A(CP)=0.002+/-0.050(stat)+/-0.030(syst) for B-->X(s)gamma events having recoil mass smaller than 2.1 GeV/c(2). The analysis is based on a data sample of 140 fb(-1) recorded at the upsilon(4S) resonance with the Belle detector at the KEKB e(+)e(-) storage ring.

Journal Article↗
PubMed2004

Study of CP violating effects in time dependent B0(B0)-->D(*)-/+pi+/- decays.

We report measurements of time dependent decay rates for B0(B(0))-->D((*)-/+)pi(+/-) decays and extraction of CP violation parameters containing phi(3). Using fully reconstructed D((*))pi events from a 140 fb(-1) data sample collected at the Upsilon(4S) resonance, we obtain the CP violation parameters for D(*)pi and Dpi decays, 2R(D((*))pi)sin((2phi(1)+phi(3)+/-delta(D((*))pi)), where R(D((*))pi) is the ratio of the magnitudes of the doubly Cabibbo-suppressed and Cabibbo-favored amplitudes, and delta(D((*))pi) is the strong phase difference between them. Under the assumption of delta(D((*))pi) being close to either 0 degrees or 180 degrees, we obtain |2R(D(*)pi)sin((2phi(1)+phi(3))|=0.060+/-0.040(stat)+/-0.019(syst) and |2R(Dpi)sin((2phi(1)+phi(3))|=0.061+/-0.037(stat)+/-0.018(syst).

Journal Article↗
PubMed2004

Effect of vermiculite addition on compost produced from Korean food wastes.

To evaluate the effect of vermiculite addition on composting food wastes from Korean households, food wastes were composted in three small bins to which different additives were added. The following three bins were employed: in Case I, only recycled compost was composted; in Case II, food wastes with recycled compost; and in Case III, food wastes with recycled compost and vermiculite. In the experiment performed for 30 days, it was confirmed that the supplementary addition of vermiculite to the composting mixture did not significantly improve the weight loss rate and the decomposition rate of food wastes. Due to dilution through the use of inorganic vermiculite, the vermiculite addition reduced the organic matter concentration of the composting mixtures. Vermiculite addition did not raise the pH value. Weight losses of roughly 70% were observed based on calculating moisture loss as well as dry food waste loss and not considering additives, while dry food waste loss was 29.4% and 35.8% with and without the addition of vermiculite, respectively. For these experiments, the major portion of the weight loss was the loss of water. The results indicate a need to differentiate between weight loss percentages and decomposition percentages, and a need to indicate if either of these percentages includes or excludes the mass of additives.

Aluminum Silicates↗
PubMed2004

Fluorescence in situ hybridization analysis of nitrifiers in piggery wastewater treatment reactors.

Fluorescence in situ hybridization (FISH) was performed to analyze the nitrifying microbial communities in an activated sludge reactor (ASR) and a fixed biofilm reactor (FBR) for piggery wastewater treatment. Heterotrophic oxidation and nitrification were occurring simultaneously in the ASR and the COD and nitrification efficiencies depend on the loads. In the FBR nitrification efficiency also depends on ammonium load to the reactor and nitrite was accumulated when free ammonia concentration was higher than 0.2 mg NH3-N/L. FISH analysis showed that ammonia-oxidizing bacteria (NSO1225) and denitrifying bacteria (RRP1088) were less abundant than other bacteria (EUB338) in ASR. Further analysis on nitrifying bacteria in the FBR showed that Nitrosomonas species (NSM156) and Nitrospira species (NSR1156) were the dominant ammonia-oxidizing and nitrite-oxidizing bacteria, respectively, in the piggery wastewater nitrification system.

Animals↗
PubMed2003

Independent association of HLA-DR and FCgamma receptor polymorphisms in Korean patients with systemic lupus erythematosus.

OBJECTIVES: To determine the distribution of HLA-DR type and FcgammaRIIa/IIIa polymorphisms, and to analyse the combined effects of these genes for susceptibility in Korean systemic lupus erythematosus (SLE) patients. METHODS: A total of 299 SLE patients meeting 1982 ACR criteria and 144 Korean disease-free controls were enrolled. Genotyping for the FcgammaRIIa 131 R/H and FcgammaRIIIa 176 F/V was performed by polymerase chain reaction (PCR) of genomic DNA using allele-specific primers. HLA-DRB1 typing was performed by the PCR-SSOP method. RESULTS: There was significant skewing in the distribution of the three FcgammaRIIa genotypes between the SLE patients and the controls [P = 0.002 for R/R131 vs R/H131 and H/H131, relative risk (RR) 2.6 (95% CI 1.3-5.2)], but not in FcgammaRIIIa genotypes. HLA-DRB1*15 allele was significantly more prevalent among SLE patients than the control population [P < 0.02, RR = 1.7 (1.1-2.6)]. HLA-DRB1 genotypes or allele frequencies of the SLE patients with nephritis did not differ significantly from those of the SLE patients without nephritis. We analysed the combined effects of the two candidate genes on SLE susceptibility. HLA-DRB1*15 allele was a significant predictor of SLE in individuals who were not homozygous for FcgammaRIIa-R/R131 [RR = 2.1 (1.2-3.7), P < 0.008], and the FcgammaRIIa-R/R131 genotype vice versa [RR = 5.3 (1.9-15.4), P < 0.001]. However, an additive or synergistic effect of both susceptible genes on relative risk for SLE was not evident. CONCLUSIONS: Our results suggest that FcgammaRIIa-R/R131 homozygote and HLA-DRB1*15 allele are independent risk factors in Korean SLE patients without additive or synergistic effects.

Adult↗
PubMed2003

Visualization of transfection of hepatocytes by galactosylated chitosan-graft-poly(ethylene glycol)/DNA complexes by confocal laser scanning microscopy.

Dual-labeled galactosylated chitosan-graft-poly(ethylene glycol) (PEG) (GCP)/DNA complexes were prepared and their hepatocyte-specific delivery and cellular distribution were investigated by confocal laser scanning microscopy (CLSM). The complexes were transfected into hepatocyte through specific interaction of galactose moiety of the GCP and asialoglycoprotein receptors (ASGPR) of the hepatocytes. The GCP/DNA complexes taken up by the hepatocytes were rapidly released into the cytoplasm, but nuclear trafficking of the released complexes was slow and rate-limiting process. The more efficient transfection of the complex occurred in the human-derived HepG2 cells than in primary hepatocytes.

Animals↗
PubMed2003

Studies of the decay B+/- -->D(CP)K+/-.

We report studies of the Cabibbo-suppressed decay B+/--->D(CP)K+/-, where D(CP) denotes CP eigenstates of the D0-D0; system. The analysis is based on a 29.1 fb(-1) sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e(+)e(-) storage ring. We measure ratios of branching fractions, relative to Cabibbo-favored B+/--->D(CP)pi(+/-), of B(B--->D1K-)/B(B--->D1pi(-))=0.125+/-0.036+/-0.010 and B(B--->D2K-)/B(B--->D2pi(-))=0.119+/-0.028+/-0.006; the index 1 (2) denotes the CP=+1 (-1) eigenstate. We also extract the partial rate asymmetries for B+/--->D(CP)K+/-, finding A(1)=0.29+/-0.26+/-0.05 and A(2)=-0.22+/-0.24+/-0.04.

Journal Article↗
PubMed2003

Quality of marital life in Korean patients with spondyloarthropathy.

The objectives of this study were to assess the quality of marital life (QML) in patients with spondyloarthropathy (SpA) in Korea and to identify possible gender differences in QML in patients with SpA. This was a case-control study at the outpatient unit of a tertiary care medical centre. Subjects were the patient group, composed of 47 married patients with SpA, and a comparison group composed of 47 healthy married adults with similar demographic characteristics. QML was measured using the Marital Satisfaction Inventory, Revised. As a result, QML was similar for both the male patients and the healthy men. However, the female patients had higher scores on the global distress scale (59.8 +/- 6.3 vs. 53.8 +/- 5.6, P=0.021) and the aggression scale (50.5 +/- 7.9 vs. 44.3 +/- 5.4, P=0.016) than the female comparison group. At the same time, the female patients demonstrated higher scores on the global distress scale (59.8 +/- 6.3 vs. 54.7 +/- 7.2, P=0.035) than the male patients. In conclusion, QML in Korean males with SpA was not greatly different from that of the male comparison group. However, QML in the female patients was characterised by higher global distress and a higher probability of aggression from their partner, but no significant sexual dissatisfaction.

Adaptation, Psychological↗
PubMed2003

Induction of apoptosis by 4-acetyl-12,13-epoxyl-9-trichothecene-3,15-diol from Isaria japonica Yasuda through intracellular reactive oxygen species formation and caspase-3 activation in human leukemia HL-60 cells.

Recently we have reported that the trichothecene mycotoxin 4-acetyl-12,13-epoxyl-9-trichothecene-3,15-diol (AETD) from the fruiting bodies of Isaria japonica Yasuda is a potent inducer of apoptosis in human promyelocytic HL-60 cells. The present study aims to characterize the molecular events leading to AETD-induced apoptosis in HL-60 cells. The percentage of apoptotic cells (annexin-V-positive cell population) increased dose- and time-dependently after AETD exposure. Apoptosis of HL-60 cells by AETD was associated with the formation of intracellular reactive oxygen species (ROS), the depletion of intracellular glutathione (GSH) and the activation of caspase-3. Pretreating the cells with the antioxidant N-acetyl-L-cystein (NAC) and the caspase-3 inhibitor Z-DEVD-fmk abrogated AETD-induced apoptosis and caspase-3 activation. NAC blocked intracellular ROS formation and GSH depletion, but Z-DEVD-fmk did not. These results indicate that AETD induces apoptosis in HL-60 cells by causing intracellular ROS formation and GSH depletion followed by the downstream event of caspase-3 activation.

Apoptosis↗
PubMed2002

Measurement of the B(0)-B(0) mixing parameter Deltam(d) using semileptonic B0 decays.

We present a measurement of the B0-Bmacr;(0) mixing parameter Deltam(d) using neutral B meson pairs in a 29.1 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We exclusively reconstruct one neutral B meson in the semileptonic B0-->D(*-)l(+)nu decay mode and identify the flavor of the accompanying B meson from its decay products. From the distribution of the time intervals between the two flavor-tagged B meson decay points, we obtain Deltam(d)=(0.494+/-0.012+/-0.015) ps(-1), where the first error is statistical and the second error is systematic.

Journal Article↗
PubMed2002

Radiative B meson decays into kpigamma and kpipigamma final states.

We report observations of radiative B meson decays into the K+pi(-)gamma and K+pi(-)pi(+)gamma final states. In the B0-->K+pi(-)gamma channel, we present evidence for decays via an intermediate tensor meson state with a branching fraction of B(B0-->K(*)(2)(1430)(0)gamma)=[1.3+/-0.5(stat)+/-0.1(syst)]x10(-5). We measure the branching fraction B(B+-->K+pi(-)pi(+)gamma)=[2.4+/-0.5(stat) +0.4-0.2(syst)]x10(-5), in which the B+-->K(*0)pi(+)gamma and B+-->K+rho(0)gamma channels dominate. The analysis is based on a data set of 29.4 fb(-1) recorded by the Belle experiment at the KEKB collider.

Journal Article↗
PubMed2002

Observation of B(0)-->D((*)0)pp.

The B meson decay modes B-->Dpp; and B-->D(*)pp; have been studied using 29.4 fb(-1) of data collected with the Belle detector at KEKB. The B;(0)-->D(0)pp; and B;(0)-->D(*0)pp; decays have been observed for the first time with branching fractions B(B;(0)-->D(0)pp;)=(1.18+/-0.15+/-0.16)x10(-4) and B(B;(0)-->D(*0)pp;)=(1.20(+0.33)(-0.29)+/-0.21)x10(-4). No signal has been found for the B+-->D(+)pp; and B+-->D(*+)pp; decay modes, and the corresponding upper limits at 90% C.L. are presented.

Journal Article↗
PubMed2002

Observation of double cć production in e+e- annihilation at squareroot[s] approximately 10.6 GeV.

We report the observation of prompt J/psi via double cc; production from the e+e- continuum. In this process one cc; pair fragments into a J/psi meson while the remaining pair either produces a charmonium state or fragments into open charm. Both cases have been experimentally observed. We find cross sections of sigma[e+e- -->J/psieta(c)(gamma)]xB(eta(c)-->>or=4 charged)=(0.033(+0.007)(-0.006)+/-0.009) pb and sigma(e+e- -->J/psiD(*+)X)=(0.53(+0.19)(-0.15)+/-0.14) pb and infer sigma(e+e- -->J/psicc;)/sigma(e+e- -->J/psiX)=0.59(+0.15)(-0.13)+/-0.12. These results are obtained from a 46.2 fb(-1) data sample collected near the Upsilon(4S) resonance, with the Belle detector at the KEKB collider.

Journal Article↗
PubMed2002

Observation of the decay B(0)-->D(+/-)D(*-/+).

We report the first observation of the decay B(0)-->D(+/-)D(*-/+) with the Belle detector at the KEKB e(+)e(-) Collider operated at the Upsilon(4S) resonance. The sum of branching fractions B(B(0)-->D(+)D(*-))+B(B(0)-->D(-)D(*+)) is measured to be (1.17+/-0.26(+0.22)(-0.25))x10(-3) using the full reconstruction method where both charmed mesons from B0 decays are reconstructed. A consistent value [(1.48+/-0.38(+0.28)(-0.31))x10(-3)] is obtained using a partial reconstruction technique that uses only the slow pion from the D(*-)-->D(-0)pi(-) decay and a fully reconstructed D(+) to reconstruct the B(0).

Journal Article↗
PubMed2002

Emergent excitations in a geometrically frustrated magnet.

Frustrated systems are ubiquitous, and they are interesting because their behaviour is difficult to predict; frustration can lead to macroscopic degeneracies and qualitatively new states of matter. Magnetic systems offer good examples in the form of spin lattices, where all interactions between spins cannot be simultaneously satisfied. Here we report how unusual composite spin degrees of freedom can emerge from frustrated magnetic interactions in the cubic spinel ZnCr(2)O(4). Upon cooling, groups of six spins self-organize into weakly interacting antiferromagnetic loops, whose directors -- the unique direction along which the spins are aligned, parallel or antiparallel -- govern all low-temperature dynamics. The experimental evidence comes from a measurement of the magnetic form factor by inelastic neutron scattering; the data show that neutrons scatter from hexagonal spin clusters rather than individual spins. The hexagon directors are, to a first approximation, decoupled from each other, and hence their reorientations embody the long-sought local zero energy modes for the pyrochlore lattice.

Journal Article↗