Search Results - (Author, Cooperation:E. Kang)

2018-03-15

Wiley-Blackwell

0148-0227

Geosciences

Physics

2012-10-30

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Adult ; Animals ; Cell Nucleus/genetics ; Cryopreservation ; Cytoplasm/genetics ; DNA, Mitochondrial/analysis/genetics ; Embryo, Mammalian/embryology ; Embryonic Stem Cells/cytology ; Female ; Fertilization ; *Genetic Therapy ; Humans ; Macaca mulatta/genetics/growth & development ; Microsatellite Repeats/genetics ; Mitochondrial Diseases/*genetics/*therapy ; Nuclear Transfer Techniques/*standards ; Oocytes/cytology ; Pregnancy ; Young Adult ; Zygote/cytology/pathology

2018-11-16

American Society of Hematology (ASH)

0006-4971

1528-0020

Biology

Medicine

Red Cells, Iron, and Erythropoiesis, Clinical Trials and Observations

2014-07-11

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Animals ; Cell Line ; *Cellular Reprogramming ; Chromosome Aberrations ; Chromosomes, Human, X/genetics/metabolism ; DNA Copy Number Variations ; DNA Methylation ; Genome-Wide Association Study ; Genomic Imprinting ; Humans ; Nuclear Transfer Techniques/standards ; Pluripotent Stem Cells/cytology/*metabolism ; Transcriptome

2014-03-29

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Animals ; Cell Count ; *Cellular Reprogramming ; Cloning, Organism ; Cytoplasm/*metabolism ; Embryo, Mammalian/*cytology ; Embryonic Stem Cells/*cytology ; Female ; Induced Pluripotent Stem Cells/*cytology ; *Interphase ; Male ; Metaphase ; Mice ; *Nuclear Transfer Techniques

2015-07-16

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Adenosine Triphosphate/metabolism ; Animals ; Cell Line ; DNA, Mitochondrial/*genetics ; Embryo, Mammalian/cytology ; Fibroblasts/cytology/metabolism/pathology ; Gene Expression Profiling ; Haplotypes/genetics ; Humans ; Induced Pluripotent Stem Cells/*metabolism ; Leigh Disease/genetics/metabolism/pathology ; Mice ; Mitochondria/*genetics/*metabolism/pathology ; Mitochondrial Diseases/*genetics/*metabolism/pathology ; Mitochondrial Encephalomyopathies/genetics/metabolism/pathology ; Mutation/genetics ; Nuclear Transfer Techniques ; Nucleotides/genetics ; Oxygen Consumption ; Polymorphism, Single Nucleotide/genetics ; Sequence Analysis, RNA ; Skin/cytology

2018-10-26

American Society of Hematology (ASH)

0006-4971

1528-0020

Biology

Medicine

Pediatric Hematology, Immunobiology and Immunotherapy, Transplantation, Plenary Papers

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

The chemical nature of the nitrogens corresponding to various intrinsic redox states of polypyrrole (PPY) and polyaniline (PAN) has been critically compared using x-ray photoelectron spectroscopy (XPS) as a primary tool. Proton modifications of nitrogens in PPY give rise to a number of intrinsic redox states analogous to those observed in PAN. The behavior of the corresponding oxidation states in both polymers towards oxidation/reduction, deprotonation/reprotonation, or charge–transfer interactions with electron acceptors are grossly similar. However, the nitrogens of the two oxidized polymer complexes do differ in their thermal degradation behavior which suggests that the oxidized pyrrolylium nitrogens are more susceptible to deprotonation than their oxidized counterparts.

Electronic Resource

1551-2916

Blackwell Publishing Journal Backfiles 1879-2005

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Physics

The effects of initial particle size on the microstructure of silicon nitride ceramics produced by pressureless sintering have been investigated. The microstructures of the silicon nitride ceramics varied considerably with the size of the initial powder. With decreasing powder size, abnormal grain growth was enhanced, which resulted in significant bimodal distribution of grain size. The observed results are discussed in relation to the two-dimensional nucleation and growth theory for faceted crystals.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

We report on a hydrogen barrier necessary for a conventional passivation process of integrated SrBi2Ta2O9 (SBT)-based memories. The passivation process significantly degraded electrical properties of the memories, resulting from hydrogen damage in the SBT capacitors. Metallic films (Ti, TiN, and Al) were investigated as a hydrogen barrier during the passivation process. The Ti(〉500 Å) hydrogen barrier only showed the electrical properties of memories free from hydrogen damage. The formation of stable hydrides and the suppressed diffusion of hydrogen through the Ti films during the passivation processes resulted in sufficient switching polarization, low leakage current, and good reliabilities at high temperature. © 2000 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The charge-transfer (CT) interactions in electroactive polymeric complexes formed by nonconjugated polymers: poly-2-vinylpyridine, poly-4-vinylpyridine, and various halobenzoquinone electron acceptors such as: o-chloranil, p-chloranil, o-bromanil, and p-fluoranil have been investigated by means of x-ray photoelectron spectroscopy (XPS). In spite of the relatively high degree of CT interactions, the conductivity of the complexes remains low and in the range of 10−11–10−6 S cm−1. XPS core-level spectra for halogens, nitrogen, and oxygen allow the steric hindrance to CT interactions in the various complexes to be investigated and compared. In all the complexes, the presence of a halogen anion, a positively charged pyridinium nitrogen, and an oxygen anion is observed. This is indicative that CT interactions may have resulted in adducts arising from the formation of linkages between the polymers and the acceptors.

Electronic Resource

1365-2222

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Background Allergic rhinitis is a known predictor and correlate of asthma incidence. However, it is not clear which patients with allergic rhinitis are at greater risk of the development of asthma.Objective The aim of this study was to investigate whether airway hypersensitivity and/or increased maximal response on the dose–response curve to methacholine would predict the development of asthma in subjects with allergic rhinitis.Methods One hundred and forty-one children with allergic rhinitis were prospectively studied for 7 years. At the initiation of the study, bronchial provocation test with methacholine using a stepwise increasing concentration technique was performed to measure PC20 (provocative concentration causing a 20% fall in FEV1) and maximal response. Each subject was evaluated at least every 6 months and details of asthmatic symptoms or signs experienced during the intervening period were taken.Results Twenty of 122 subjects available for the follow-up developed asthma. Nine (19.6%) of 46 hypersensitive (PC20 〈 18 mg/mL) subjects developed asthma, compared with 11 (14.5%) of 76 normosensitive subjects (P = 0.462). Eight (32%) of 25 subjects without maximal response plateau developed asthma, compared with 12 (12.4%) of 97 subjects with maximal response plateau (P = 0.018). Score test for trend revealed a significant association between the level of maximal response (P = 0.007), but not the degree of methacholine PC20 (P = 0.123), and the future development of asthma.Conclusion An increased maximal airway response to methacholine is shown to be a better predictor for the future development of asthma in patients with allergic rhinitis, than airway hypersensitivity to methacholine.

Electronic Resource

0141-8130

aqueous two-phase system ; carbohydrate-carbohydrate interaction ; polysaccharide-coated liposomes

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Chemistry and Pharmacology

Electronic Resource

1432-0509

Key words: Liver, neoplasms—Magnetic resonance, rapid imaging—Magnetic resonance, comparative studies—Magnetic resonance, pulse sequences.

Springer Online Journal Archives 1860-2000

Medicine

Abstract Background: To evaluate the diagnostic efficacy of fast T2-weighted magnetic resonance (MR) imaging sequences on image quality, hepatic lesion detection, and lesion conspicuity. Methods: Three breath-hold, fast T2-weighted sequences with turbo-spin-echo (TSE), half-Fourier acquisition single-shot TSE (HASTE), and inversion recovery (IR) HASTE techniques were examined for 43 lesions in 20 consecutive patients. Evaluation was performed qualitatively on image quality and lesion detectability and quantitatively on lesion conspicuity by using lesion/liver signal-intensity and contrast-to-noise ratios. Results: Artifacts were significantly less present on the HASTE sequence (p 〈 0.01). Both TSE and HASTE sequences detected 39 lesions (91% each); the IR HASTE sequence detected 37 (86%). IR HASTE sequence showed a significantly higher signal-intensity ratio than did the others (p 〈 0.01). Conclusions: Breath-hold TSE versus breath-hold HASTE or IR HASTE is still the most robust sequence in lesion detection, image quality, and lesion conspicuity. However, the HASTE sequence offers good lesion detection and image quality, and the IR HASTE has a better signal-intensity ratio.

Electronic Resource

1432-1114

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract  In this paper we discuss a novel application of holographic interferometry in the simultaneous quantitative visualization of high-speed, oscillatory flow and temperature fields in complex flow geometries. We consider cases of (i) self-sustained oscillatory flows with main flow imposed in grooved and communicating channels as well as (ii) oscillating thermofluid processes with zero mean velocity in a thermoacoustic refrigerator model. Examples showing unsteady temperature distributions obtained by real-time holographic interferometry combined with high-speed cinematography illustrate the possibilities of the approach introduced in the paper. Our study shows that temperature distributions accurately mirror flow structures in certain types of complex, unsteady flows, thus allowing, apart from the measurement of temperature profiles and heat transfer, also the measurement of oscillatory amplitudes, frequencies, wavelengths as well as the speed of propagation of traveling waves by applying digital image processing techniques. In the grooved and communicating channels it is possible to visualize the structure of the Tollmien–Schlichting waves through isotherms by using the infinite fringe field alignment of holographic interferometry. In the thermoacoustic refrigerator model, small amplitude temperature oscillations generated by the acoustic standing wave are visualized and measured. Image processing as well as data reduction procedures used in the analysis of these flow fields are discussed in the paper. Experimental data obtained by applying the techniques introduced in the paper show good agreement with theory and results of numerical simulations. Our study suggests that using temperature as tracer offers numerous advantages in the study of certain types of complex, unsteady flows.

Electronic Resource

1432-1084

Key words: Lung neoplasms ; CT

Springer Online Journal Archives 1860-2000

Medicine

Abstract. The aim of this study was to evaluate differences in the prevalence of patterns of CT bronchus sign in malignant solitary pulmonary lesions (SPLs), according to their histologic cell types and with respect to size, location, and degree of cell differentiation. Computed tomography scans of 78 patients, in whom pathologically confirmed malignant SPLs with CT bronchus sign were present, were randomly selected and reviewed by two radiologists under consensus. All 78 were CT scans done using spiral technique with 10-mm collimation and 10-mm reconstruction intervals with enhancement, and 75 included additional high-resolution CT scans. Lesions were classified into four cell types as squamous cell carcinoma (n = 24), small cell carcinoma (n = 12), adenocarcinoma (n = 23), bronchioloalveolar carcinoma (BAC; n = 9), and others (n = 12), into three degrees of differentiation, into three size groups, and according to location (central or peripheral). Patterns of CT bronchus sign were classified into abruptly obstructing (I), patent (II), displacing (III), or tapered narrowing (IV) types. The relationships between the patterns of CT bronchus sign and cell type and degree of cell differentiation were evaluated. Eighty patterns of CT bronchus sign were observed in 78 patients. According to cell type, squamous cell carcinoma showed most often type-I pattern (45.8 %) but no type-II pattern, which was the most common pattern observed in BAC (77.8 %) and adenocarcinoma (34.8 %; p 〈 0.01). Small cell carcinoma showed a varied distribution among the four patterns of CT bronchus sign. According to location, in central squamous cell carcinomas, type-I pattern was more common(55 %; p 〈 0.01). Bronchioloalveolar carcinoma showed more peripheral lesions and in both central and peripheral lesions, type-II pattern was significantly more common (100 and 66.7 %; p 〈 0.01). In SPLs with CT bronchus sign of obstructing pattern, especially if central location, squamous cell carcinoma should be suspected, whereas in SPLs with patent CT bronchus sign, regardless of the location, the strong possibility of BAC should be considered.

Electronic Resource

1432-1920

Key words Magnetic resonance imaging ; Echo-planar imaging ; Multiple sclerosis

Springer Online Journal Archives 1860-2000

Medicine

Abstract Our aim was to determine the relative merits of short and long echo times (TE) with single-shot echo-planar imaging for imaging cerebral lesions such as multiple sclerosis. We examined seven patients with clinically definite multiple sclerosis were imaged at 1.5 T. Patients were scanned with spin-echo, single-shot echo-planar imaging, using TEs of 45, 75, 105, and 135 ms. Region of interest (ROI) measurements were performed on 36 lesions at or above the level of the corona radiata. The mean image contrast (IC) was highest (231.1) for a TE of 45 ms, followed by 75 ms (218.9), 105 ms (217.9), and 135 ms (191.6). When mean contrast-to-noise ratios (C/N) were compared, the value was again highest (29.7) for TE 45 ms, followed by 75 ms (28.9), 105 ms (28.5), and 135 ms (26.3). In a lesion-by-lesion comparison, TE 45 ms had the highest IC and C/N in the largest number of cases (50 % and 47.2 %, respectively). IC and C/N for TE 45 ms were superior to those of 75 ms in 64 % and 58 %, respectively. These results support the use of relatively short TEs for single-shot echo-planar imaging in the setting of cerebral lesions such as multiple sclerosis.

Electronic Resource

1573-482X

Springer Online Journal Archives 1860-2000

Electrical Engineering, Measurement and Control Technology

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract X-ray photoelectron spectroscopy was employed for the in situ study of interactions between thermally evaporated Mg atoms and electroactive polyaniline (PANI) films of various intrinsic oxidation states. Quantitative changes in the N1s core-level spectra and the Mg2p core-level spectra, as well as the changes in surface chemical stoichiometry of these films throughout the Mg evaporation process were carefully monitored. Although the nitrogen sites appeared to be more attractive to the in-coming Mg atoms and the emeraldine base (EB) and nigraniline base (NA) films underwent an apparent decrease in intrinsic oxidation state ([=N-]/[-NH-] ratio) as a result of Mg evaporation, there is no direct interaction between the two species. On the other hand, the adsorbed oxygen from the bulk of the polymer film played a dominant role in the interfacial interactions between the polymer and the metal. Characterization of the delaminated indium-tin-oxide (ITO) and polymer surfaces from EB film and its camphorsulfonic acid-doped counterpart cast on ITO substrates had also been carried out to evaluate the interaction of PANI with the high work function metal.

Electronic Resource

1573-4803

Springer Online Journal Archives 1860-2000

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Abstract The chemical nature of the nitrogens in polypyrrole (PPY) and poly(N-methylpyrrole) (PMPY) has been critically compared using X-ray photoelectron spectroscopy as a primary tool. Treatment of PPY/perchlorate complex with NaOH results in a deprotonation process which gives rise to a PPY base (DP-PPY) having an intrinsic oxidation state consisting of 25% oxidized imine-like (=N-) structure, similar to that observed in the 50% oxidized emeraldine state of polyaniline. This intrinsic oxidation state, however, does not exist in the nitrogen-substituted PPY. As a result, the charge-transfer (CT) mechanisms involving the two base polymers and the various oxidants and electron acceptors are vastly different. The PMPY base undergoes strong CT interactions with metal oxidants, such as Cu(ClO4)2, but interacts only weakly with organic electron acceptors, such as the halobenzoquinones and cyanobenzoquinones. The reverse is true for DP-PPY. Both polymer complexes also exhibit different thermal degradation behaviour.

Electronic Resource

1432-5195

Springer Online Journal Archives 1860-2000

Medicine

Résumé Sur 26 chiens adultes, on a réalisé une perte de substance cortico-spongieuse dans le condyle externe de chaque fémur (soit 52 fémurs), et la cavité ainsi créée a été traitée par cryochirurgie, cautérisation au phénol ou obturation par du ciment osseux. Les animaux ont été sacrífiés après 1, 4, 12 semaines (et 24 semaines pour le groupe traité par cryochirurgie) afin de comparer l'étendue de la nécrose lìée à chaque traitement, et d'observer le processus de cicatrisation. Après cryochirurgie, la nécrose était profonde et intéressait une épaisseur de 2.5 à 14 mm autour de la cavité osseuse, représentant en moyenne 365% du volume de la cavité initiale. L'action du phénol était négligeable, car seuls quelques foyers nécrotiques microscopiques ont été observés sur les parois de la cavité. L'obturation par du ciment osseux entraînait une zone de nécrose d'une épaisseur régulière de 1.3 à 2.8 mm autour de la cavité, représentant en moyenne 153% de la cavité d'origine. La régénération des tissus dans la zone nécrosée après cryochirurgie était minime jusqu'à 4 semaines. Cependant après 12 semaines des zones de régénération étaient nettement identifiables en quantité importante, et la cicatrisation était presque complète à la 24é semaine. Le régénération de l'os nécrosé après obturation par du ciment osseux était rapidement identique aux spécimens de contrôle. Ces observations permettent de penser que la cryochirurgie pourrait jouer un rôle significatif comme complément du curetage, dans les tumeurs osseuses localisées, bénignes ou malignes. Par contre la cautérisation par le phénol ne semble pas un traitement adéquat. Enfin, bien que l'étendue de la nécrose soit relativement limitée, l'obturation par le ciment osseux peut être considérée comme utilisable dans les cas bénins.

Summary A corticocancellous core was removed from the lateral condyle of both femurs in 26 skeletally mature dogs. The cavity was treated with cryosurgery, phenol cautery or packing with bone cement. The animals were killed after 1, 4, and 12 weeks in the phenol and cement groups, and also after 24 weeks in the cryosurgery group. The extent of the bone necrosis and healing was assessed in each group. After cryosurgery the extent of necrosis was profound in that the area of damage was 365% compared to the area of the cavity; the depth of necrosis extended between 2.5 and 14 mm, beyond the cavity wall. The effect of phenol was negligible in that only microscopic areas of superficial focal necrosis were found around the cavity wall. Bone cement produced an area of necrosis of 153% compared with the cavity, with a depth of between 1.3 and 2.8 mm. Regeneration in the region of necrosis after cryosurgery was only scanty by 4 weeks, but by 12 weeks considerable areas of regeneration were identified and complete healing was observed by 24 weeks. Regeneration of the necrotized bone produced by bone cement packing was rapid and similar to that of the control specimens. These findings suggest that cryosurgery could play a significant role as a surgical adjunct to curettage in locally aggressive benign bone tumours and in some malignancies. Phenol cautery is not regarded as an adequate treatment after curettage of bone tumours. Although the extent of necrosis was relatively small, packing with bone cement is thought to be a useful choice in benign cases.

Electronic Resource