Search Results - (Author, Cooperation:S. H. Han)

2018-05-30

American Physical Society (APS)

1098-0121

1095-3795

Physics

Magnetism

2018-10-23

The American Association of Immunologists (AAI)

0022-1767

1550-6606

Medicine

2013-02-01

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

2015-07-18

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

2018-07-19

American Physical Society (APS)

1098-0121

1095-3795

Physics

Superfluidity and superconductivity

1089-7550

AIP Digital Archive

Physics

The presence of oxygen in silicon-germanium can have a significant effect on the sintering, microstructural, and transport properties of these alloys. A neutron activation study was performed to follow the total oxygen content during the preparation of mechanically alloyed n-type Si-20 at. % Ge alloys using either fine powders, polycrystalline Czochralski chunk, or single-crystal float zoned starting materials. The alloys were prepared with a nominal composition of Si0.747Ge0.187(GaP)0.016P0.034. The total oxygen concentration was measured in the starting materials, after 6 h of mechanical alloying in a helium environment, after hot pressing, and after a 3 h, 1100 °C heat treatment in fused silica ampoules. Alloys that contained oxygen levels in excess of 2.0 at. % exhibited low carrier mobility and low thermal conductivity, whereas those that contained less than 0.6 at. % oxygen possessed high mobility and thermal conductivity. The microstructure, as observed by optical metallography and scanning electron microscopy, was found to differ greatly with oxygen content as the low oxygen alloys showed relatively large, well-defined grains and the high oxygen alloys showed evidence of poor sintering and limited grain growth.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Induced anisotropy with a large energy of 6×104 J/m3 is formed in an amorphous Sm–Fe based thin film by sputtering under an applied magnetic field of 500–600 Oe. The induced anisotropy results in a large anisotropy in magnetostriction, a strain anisotropy ratio reaching as high as 35, although intrinsic magnetostriction is affected only slightly. The large strain anisotropy allows one to realize a large strain in a particular direction and, hence, it is of significant practical importance. Induced anisotropy is also found to be formed by postannealing under applied magnetic field, but the magnitude of anisotropy energy formed is very small. © 2000 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Effects of Sm on the magnetic and magnetostrictive properties of Tb–Fe thin films are investigated. Four alloy systems, RxFe100−x (R=Tb+Sm) with x=39.8, 41.9, 43.7, and 45.8, are examined with Sm content varied from 0 (Sm free) to 2.2 at. %. In-plane anisotropy is found to be enhanced by the addition of Sm and the strongest in-plane anisotropy occurs in the Sm content range of 1 to 2 at. % depending on R content. At low magnetic fields of 1000 Oe and below, magnetostriction increases significantly with increasing Sm content, and reaches a maximum at an intermediate Sm content where well-developed in-plane anisotropy is observed. At higher magnetic fields of 3000–5000 Oe, however, no substantial improvement of magnetostriction occurs with the addition of Sm. The Sm content dependences of magnetization and coercive force are also examined. © 1999 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The electrical resistivity, thermoelectric power (Seebeck coefficient), Hall effect, and thermal conductivity have been measured in Cux(Dy2S3)1−x compounds with the η-orthorhombic structure in the composition range 0.006≤x≤0.15 in order to determine their potential as high temperature (300–1000 °C) thermoelectric materials. In this temperature and composition range Cu-doped Dy2S3 behaves as a degenerate semiconductor and shows itinerant conduction. The electrical resistivity and the Seebeck coefficient increased with increasing temperature and reach a maximum value of 4.35–7.13 mΩ cm and −163 to −177 μV/°C, respectively, depending upon the Cu concentration. A maximum power factor of 7.9 μW/cm °C2 for the Cu0.039(Dy2S3)0.961 alloy was observed at 690 °C. The 300–1000 °C integrated average power factor shows that the optimum Cu-doping level in the Dy2S3 matrix is 5–7 at. %. The thermal conductivity of Cu0.039(Dy2S3)0.961 decreased with increasing temperature from 300 to 1000 °C and was governed by both electronic and lattice contributions up to 600 °C, but above 600 °C the electronic contribution is predominant. The 300–1000 °C integrated average thermal conductivity of Cu0.039(Dy2S3)0.961 is 18.38 mW/cm °C, which gives this material a maximum figure of merit Z of 0.440×10−3/°C at 800 °C. © 1994 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Controlled amounts of GaP and P were added to a Si0.8Ge0.2 matrix by a powder-metallurgical technique in order to evaluate the optimum composition for thermoelectric applications. Bulk determination of the gallium and phosphorus content in fully dense, hot pressed compacts was performed by inductively coupled plasma atomic emission spectroscopy. The transport properties of the compacts were characterized by Hall effect measurements at room temperature and by measurements of electrical resistivity, Seebeck coefficient, and thermal diffusivity to 1000 °C. Considerable variation in the electrical transport properties were found to accompany changes in the Ga/P ratio, in the total amount of dopant, and changes in other preparation conditions. Alloys with gallium phosphide additions exhibit carrier concentrations higher than those obtained in alloys doped only with phosphorus. Alloys with a nominal phosphorus content greater than 2.0 at. % were found to be overdoped and those containing less than 0.6 at. % phosphorus were found to be underdoped relative to the material's maximum figure of merit. Room temperature electron mobilities greater than 40 cm2/V s were commonly obtained in samples with a carrier concentration of 3×1020 cm−3 or greater. A 300–1000 °C integrated average figure of merit (Z=S2/ρΛ) of 0.93×10−3 °C−1 was achieved within an optimum composition range of 0.8–1.2 at. % P and 0.6–0.8 mol % GaP, which is 20% higher than current n-type Si-Ge alloys doped with 0.59 at. % P as used in the Voyager, Galileo, and Ulysses missions. © 1995 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Fe-Hf-C-N films with excellent soft magnetic properties were fabricated by Ar+N2 reactive sputtering for the first time. The newly developed films were found to have better soft magnetic properties than those of Fe-Hf-C or Fe-Hf-N films. The best magnetic properties achieved in this work are Hc of 0.15 Oe, μeff of 8200, and 4πMs of 17 kG. The thermal stability of the Fe-Hf-C-N films was also found to be excellent, e.g., Hc was less than 0.3 Oe and μeff was about 4000 for the films annealed up to 700 °C. It was observed by transmission electron microscopy that the films consisted of two phases: a fine crystalline α-Fe phase whose grain size is about 6 nm, and Hf(C,N) precipitates with a size of less than 2 nm. The fine grained α-Fe structures, together with finely dispersed Hf(C,N) precipitates, is considered to be one of the main factors for the excellent magnetic properties and thermal stability.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Mach–Zehnder interferometry was used to measure the Pockels effect in a poled electro-optic polymer thin film with a coplanar electrode structure. The beam at the sample arm of the Mach–Zehnder interferometer passed through a polymer thin film which had been spin-coated on top of a clear gap between two electrodes patterned on an optical substrate. This unique optical geometry enabled the Pockels coefficients of the poled electro-optic polymer film in the directions of the ordinary and the extraordinary optic axes to be determined independently. As an example, the tensor ratio r33/r13 for a stilbene-dye-doped polyimide guest/host polymer film was determined experimentally; the ratio turned out to be 4.6, which was higher than the value of 3 predicted by the thermodynamic model. © 1996 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Mach-Zehnder interferometry is employed to measure the Pockels coefficients in a poled thin polymer film, which serves as a reflection mirror in the sample arm of the interferometer. As a complete optical characterization of the electro-optic polymer film, the modulated light intensity of the Mach-Zehnder interferometer is investigated as a function of the optical bias in the reference arm, the modulation voltage applied to the film, the polarization angle of the incident light, and the angle of incidence on the film. The Mach-Zehnder interferometry measurement of the Pockels coefficients in the reflection configuration has an advantage over single-beam polarization interferometry in permitting the independent determination of the Pockels tensor components, r13 and r33. Particularly, in a reflection configuration two-beam interferometric measurement, a proper consideration of the optical path change due to the refractive angle change is found to be critical in determining the absolute values of the Pockels coefficients. © 1998 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The magnetic and structural properties of as-sputtered nanocrystalline Fe–Al–O films, fabricated by a magnetron sputtering apparatus, are investigated as a function of the sputtering input power and the contents of Al and oxygen. A nanocrystalline Fe88.5Al3.5O8.0 film is found to have 4πMs of 18.2 kG, Hc of 0.6 Oe, μeff of 4600 up to 100 MHz. These excellent soft magnetic properties and high frequency characteristics result from nanocrystalline structure, high electrical resistivity, and moderate anisotropy field. These values are sufficient to apply to a high-density recording head. © 2000 American Institute of Physics.

Electronic Resource

1468-2494

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

This study presents a new approach that can stabilize effectively l-ascorbic acid in water-in-oil-in-water (w/o/w) double emulsions. Basically, the behavior of l-ascorbic acid in the aqueous phase was observed, considering its molecular deformation. Then, it was found that the stability determined in the aqueous phase by high-performance liquid chromatography (HPLC) showed that the collapse of ionization of l-ascorbic acid played a crucial role in protecting the molecular deformation. Then, the stable aqueous system was incorporated into the internal aqueous phase of the double emulsions. From the PLC analysis, it was observed that the l-ascorbic acid in an appropriate system showed high molecular stability for a long time. Moreover, in the measurement of in vitro skin permeation, the l-ascorbic acid stabilized in this study showed considerable skin permeation ability, indicating its potential applicability in pharmaceutics and cosmetics.

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1365-3083

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

We have examined the effects of ingestion of chemically denatured ovalbumin (OVA) in mice. Both 8 M urea-denatured OVA (UD-OVA) and carboxymethylated UD-OVA (CM-OVA) were purified by gel filtration. Specific IgG antibody and systemic delayed-type hypersensitivity (DTH) responses to OVA were not suppressed by CM-OVA fed prior to or after immunization with OVA in complete Freund's adjuvant (CFA). When CM-OVA was used instead of OVA for immunization, serum IgG and DTH responses to CM-OVA were orally tolerized by OVA, but not by UD-OVA or CM-OVA. Studies of antigen uptake in mice using sandwich ELISA tests showed that OVA, but not CM-OVA, was absorbed after antigen ingestion. In vitro studies further demonstrated that CM-OVA was digested much more rapidly than OVA. Moreover, studies using bovine serum albumin (BSA) demonstrated that both IgG and DTH responses to BSA were orally tolerant to BSA, but not to denatured BSA. Finally, studies using human gamma-globulin (HGG), a well-known tolerogen, also found that the IgG antibody response to HGG was not orally tolerized by denatured HGG. These results suggest that complete denaturation of globular proteins may affect their processing and absorption in the gut and thus abrogates oral tolerance induction.

Electronic Resource

1365-2222

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

A monoclonal antibody (MoAb P40) against the 68 kD major allergen of penicillium notatum (P. notatum) was obtained by immunizing the mouse with a crude extract of P. notatum. Analysed by two-dimensional gel electrophoresis and immunoblotting, P40 reacted with two different isoforms of the 68 kD component of P. notatum with pIs of 5.4 and 5.5. In addition to P. notatum, P40 showed positive ELISA activity to Aspergillus fumigatus (A. fumigatus) but not to components of six other fungi including Alternaria porri, Cladosporium cladosporoides, Aureobasidium pullulans, Fusarium solani, Rhizopus arrhizus and Candida albicans. Analysed by ELISA, MoAb P40 also showed positive activity to two (P. frequentans and P. roseopurpureum) of the 10 other Penicillium species and two (A. terreus and A. flavus) of the four other Aspergillus species tested. SDS-PAGE and immunoblotting studies demonstrated P40 positive reactivity to components with MW of about 67 kD in all these Penicillium and Aspergillus species with positive ELISA activity to P40. Furthermore, immunoblotting activity of MoAb P40 to the 67 kD component of A. niger was also observed. The epitope of the 68 kD allergen of P. notatum recognized by MoAb P40 was resistant to treatment of periodate oxidation with concentration of NaIO4 up to 20 mm. This MoAb may thus be useful in the characterization and purification of the 68 kD allergen from crude extracts, and in the molecular cloning of allergen genes.

Electronic Resource

1365-2222

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Aspergillus species are common airborne fungi that have been identified as causative agents of extrinsic bronchial asthma. More than 10 allergens from A. fumigatus have been recently characterized by cDNA cloning.The objective of this study is to identify A. fumigatus allergens through immunoblot analysis using sera from asthmatic patients.IgE-binding components of A. fumigatus and IgE cross-reactivity among allergens of different prevalent airborne fungal species were analysed by immunoblot and immunoblot inhibition, respectively, using sera from asthmatic patients. The N-terminal amino acid sequences of major allergens identified were determined by Edman degradation.Among two batches (70 and 41 sera) of asthmatic sera tested, 19 (27%) and 14 (34%), respectively, have IgE immunoblot reactivity towards components of A. fumigatus. A 34-kDa protein that reacts with IgE antibodies in 15 (79%) and 11 (79%) of the 19 and 14 positive samples, respectively, may be considered a major allergen of A. fumigatus. The N-terminal amino acid sequences of the 34 kDa major allergen and the 30.5 and 30 kDa IgE-binding components of A. fumigatus showed sequence identity to that of the vacuolar serine proteinase from A. fumigatus. The results from immunoblot inhibition show IgE cross-reactivity among major allergens of A. fumigatus, P. notatum and P. oxalicum.Results obtained suggest that the 34 kDa major allergen of A. fumigatus may be a vacuolar serine proteinase. There is IgE cross-reactivity among serine proteinase allergens of A. fumigatus, P. notatum and P. oxalicum.

Electronic Resource

1365-2222

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Alkaline and/or vacuolar serine proteinases are major allergens in prevalent airborne Penicillium and Aspergillus species.〈section xml:id="abs1-2"〉〈title type="main"〉ObjectiveThe object of this study is to generate and characterize monoclonal antibodies against these serine proteinase allergens.〈section xml:id="abs1-3"〉〈title type="main"〉MethodsBALB/c mice were immunized individually with the Penicillium citrinum culture medium or the crude extract and culture medium preparations of Aspergillus fumigatus. Hybridoma cells that secrete monoclonal antibodies against serine proteinase allergens were selected by immunoblotting. Antigens in three different Penicillium (P. citrinum, P. notatum and P. oxalicum) and two different Aspergillus species (A. fumigatus, and A. flavus) recognized by these monoclonal antibodies were analysed by sodium dodecyl sulphate and two-dimensional polyacrylamide gel electrophoresis immunoblotting and N-terminal amino acid sequence analysis.〈section xml:id="abs1-4"〉〈title type="main"〉ResultsFour (PCM8, PCM10, PCM16 and PCM39) and one (FUM20) monoclonal antibodies against serine proteinase allergens were generated after fusion of NS-1 cells with spleen cells obtained from BALB/c mice immunized with antigens from P. citrinum and A. fumigatus, respectively. Immunoblotting results showed that PCM8 reacted with an alkaline serine proteinase allergen in P. citrinum and P. notatum. PCM10 and PCM39 reacted with the alkaline serine proteinase in two Penicillium (P. citrinum, P. notatum) and two Aspergillus species (A. fumigatus, and A. flavus) tested. PCM16 reacted with the alkaline serine proteinase allergen in P. citrinum, A. fumigatus and A. flavus but not with that in P. notatum. MoAb FUM20 reacted with the alkaline serine proteinase allergen in two Aspergillus species (A. fumigatus and A. flavus) but not with that in two different Penicillium species (P. citrinum, P. notatum) tested. Among these five monoclonal antibodies generated, only PCM39 and FUM20 can react with the vacuolar serine proteinase allergen in P. notatum, P. oxalicum and in A. fumigatus. The 35 kDa P. citrinum component that reacted with FUM20 has an N-terminal amino acid sequence of DSPSVEKNAP.〈section xml:id="abs1-5"〉〈title type="main"〉ConclusionFive monoclonal antibodies against different epitopes of the serine proteinase major allergens in prevalent Penicillium and Aspergillus species were generated in the present study. Antibodies obtained may be useful in the characterization and standardization of serine proteinase allergens in crude fungal extracts.

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