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  • 1
    Digitale Medien
    Digitale Medien
    Magnetic properties of Co–P powders produced by chemical reduction (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 7209-7212 
    Details
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Co–P powders were produced by chemical reduction. The powders had a spherical shape with an average diameter of about 1 μm. X-ray diffraction and differential scanning calorimetry studies confirmed that the powders were amorphous. The amorphous powders showed higher saturation magnetization than the crystalline counterparts. Heat treatment of the powders above the crystallization temperature resulted in the formation of fcc Co, hcp Co, and Co2P phases. The saturation magnetization of the annealed powders monotonically decreased as the annealing temperature increased. On the other hand, the coercivity of the annealed powders rapidly increased with increasing annealing temperature. The powders annealed at 600 °C had a saturation magnetization of 100 emu/g with a coercivity of 500 Oe. © 2000 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1327290
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  • 2
    Digitale Medien
    Digitale Medien
    On the plug potential formation mechanism in a tandem mirror (2002)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 9 (2002), S. 3449-3458 
    Details
    ISSN: 1089-7674
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A formation mechanism of the plug potential in a tandem mirror is proposed. The orbits for ions, which are accelerated by the thermal barrier potential, are calculated numerically in a magnetic mirror field. A non-Maxwellian electron distribution function, which leads to a modified Boltzmann law, is assumed in order to determine the electrostatic potential profile. Monte Carlo simulation is carried out for ion dynamics to include the effects of Coulomb collisions and ion radial losses. It is found that the plug potential is formed under the condition that the ions trapped in the thermal barrier region are few. © 2002 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1489424
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  • 3
    Digitale Medien
    Digitale Medien
    High-density plasma production with potential confinement in the GAMMA 10 tandem mirror : The 42nd annual meeting of the division of plasma physics of the American Physical Society and the 10th international congress on plasma physics (2001)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Plasmas 8 (2001), S. 2066-2070 
    Details
    ISSN: 1089-7674
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The improvement of potential confinement was attained in the GAMMA 10 tandem mirror [Phys. Rev. Lett. 55, 939 (1985); Proceedings of the 13th International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Washington, 1990 (International Atomic Energy Agency, Vienna, 1991), Vol. 2, p. 539] by axisymmetrization of heating systems for the plasma production, heating, and potential formation. A significant increase of the density and diamagnetism by the potential confinement was observed. In the previous experiment, it was difficult to increase the central cell density higher than 2.7×1018 m−3. One of the possible mechanisms is the density clamping due to the eigenmode formation of the ion–cyclotron-range of frequency (ICRF) waves in the axial direction. With high harmonic ICRF waves (RF3), the experiments to overcome this problem have been performed. In preliminary experiments with RF3 and NBI the maximum density of 4×1018 m−3 was attained. © 2001 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1350962
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  • 4
    Digitale Medien
    Digitale Medien
    Aligning single-wall carbon nanotubes with an alternating-current electric field (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 3714-3716 
    Details
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Single-wall carbon nanotubes (SWCNTs) were highly aligned by an external electric field. The results suggest that the alignment of SWCNTs shows significant dependencies on the frequency and the magnitude of the applied electric field. The electric field with 5 MHz straightened out the SWCNTs and created highly oriented samples with fewer large particles. We also discussed the mechanism and applications. © 2001 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.1377627
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  • 5
    Digitale Medien
    Digitale Medien
    Cytotoxicity of bisphenol A glycidyl methacrylate on cytochrome P450-producing cells (2003)
    Oxford, UK : Blackwell Science Ltd
    Journal of oral rehabilitation 30 (2003), S. 0 
    Details
    ISSN: 1365-2842
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: summary  Of the cytochrome P450 (CYP) family of carcinogen-activating enzymes, CYP3A is the major form found in human livers. The purpose of this study was to investigate the cytotoxic effects of dental resin monomers after being metabolized by CYP3A4 and CYP3A7, using a colony formation assay and a neutral red assay. Specimen wells were plated with transfected cells derived from the Chinese hamster lung at 100 cells well−1. The experimental group consisted of CYP-producing 3A4-10 and 3A7-40 cells, while the control group consisted of non-CYP-producing CR-119 cells. Bisphenol A (BPA) and bisphenol A glycidyl methacrylate (Bis-GMA) and a positive control (Aflatoxine Bl) were added separately to each well and cultured for 7 days. After cultivation, the number of the colonies was counted and IC50 values were determined. The data were statistically analysed by a Student's t-test. The resultant of IC50 values indicated that the monomers were not metabolically activated by CYP3A4 or CYP3A7 as compared with the control (P 〈 0·05). We also confirmed that these monomers act neither as activators nor as inhibitors of CYP3A4 and CYP3A7.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1365-2842.2003.01109.x
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  • 6
    Digitale Medien
    Digitale Medien
    Matrix metalloproteinase-2 expression correlates with morphological and immunohistochemical epithelial characteristics in synovial sarcoma (2002)
    Oxford UK : Blackwell Science Ltd.
    Histopathology 40 (2002), S. 0 
    Details
    ISSN: 1365-2559
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Matrix metalloproteinase-2 expression correlates with morphological and immunohistochemical epithelial characteristics in synovial sarcoma Aims: Synovial sarcoma is a unique mesenchymal tumour characterized by the presence of epithelial differentiation, although the mechanism involved in the epithelial morphology is still unclear. The aim of this study was to evaluate the function of matrix metalloproteinase-2 (MMP-2) in synovial sarcoma, in order to assess whether MMP-2 expression plays an important role in epithelial differentiation, or whether it contributes to a poor clinical outcome. Methods and results: Immunohistochemical stainings for MMP-2, cytokeratins (CKs) 7, 8, 18 and 19, and E-cadherin were performed for 58 (44 monophasic and 14 biphasic) cases of synovial sarcoma, and we compared the expression of these proteins with the histological and clinical findings. MMP-2 and E-cadherin expression was observed in 43 cases (74.1%) and in 18 cases (31.0%), respectively. Expression of these proteins was preferentially observed in the glandular components of biphasic tumours or the epithelioid areas of monophasic tumours. Statistically significant correlations were recognized between MMP-2 expression and E-cadherin expression of biphasic subtype. Moreover, there were statistically significant correlations between monophasic tumours with epithelioid areas and MMP-2 expression or E-cadherin expression. MMP-2 expression was correlated with epithelial differentiation as assessed by CK immunoreactivity. The expression of MMP-2 did not affect the overall survival rate in synovial sarcoma. Conclusions: MMP-2 expression seemed to have an important role to play in the epithelial differentiation of tumour cells in synovial sarcoma, through remodelling of the extracellular matrix and by changing the cytoskeletal interaction between the extracellular matrix and tumour cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1365-2559.2002.01345.x
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  • 7
    Digitale Medien
    Digitale Medien
    Secondary malignant giant-cell tumour of bone: molecular abnormalities of p53 and H-ras gene correlated with malignant transformation (2001)
    Oxford UK : Blackwell Science Ltd
    Histopathology 39 (2001), S. 0 
    Details
    ISSN: 1365-2559
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Secondary malignant giant-cell tumour of bone: molecular abnormalities of p53 and H-ras gene correlated with malignant transformation Aims: We report two cases of secondary malignant giant-cell tumour occurring without irradiation therapy. To elucidate the mechanism of malignant transformation in this tumour, we searched for the molecular abnormalities of p53, MDM2 and the H-ras genes. Methods and results: These cases were retrieved after a review of 103 cases of primary giant-cell tumour of bone, registered in our institute. One case occurred in the distal femur of a 42-year-old female after surgical curettage, while the other arose in the acetabulum of a 25-year-old male after en bloc resection. Microscopically, the malignant tumour in the distal femur was composed of a proliferation of ovoid or fusiform cells arranged in fascicles with high mitotic activities. The malignant transformed tumour in the acetabulum was made up of pleomorphic tumour cells with atypical mitoses. In the tumour of the distal femur, both p53 and H-ras mutations were detected. Abnormal nuclear accumulation of p53 protein and c-myc expression were also revealed by immunohistochemistry. In both cases, the recurrent malignant tumour over-expressed MMP-9 and revealed a higher MIB-1-labelling index compared with the primary conventional giant-cell tumour. Conclusions: Our results suggest that multiple oncogene or tumour suppressor gene mutations may play an important role during malignant transformation in conventional giant-cell tumours.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1365-2559.2001.01275.x
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  • 8
    Digitale Medien
    Digitale Medien
    Pathological Role of Aquaporin-2 in Impaired Water Excretion and Hyponatremia (2004)
    Oxford, UK : Blackwell Science Ltd
    Journal of neuroendocrinology 16 (2004), S. 0 
    Details
    ISSN: 1365-2826
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: In the syndrome of inappropriate secretion of antidiuretic hormone (SIADH), inappropriately elevated secretion of vasopressin can result in a reduction of antidiuretic efficacy: a phenomenon known as ‘vasopressin escape’. We compared experimental SIADH with 1-deamino-8-d-arginine vasopressin (dDAVP)-excess rats, where both groups received continuous subcutaneous administration of dDAVP by osmotic minipump but the SIADH rats also received a liquid diet that induced hyponatraemia. The SIADH rats, but not the dDAVP excess rats, showed a marked attenuation of urinary concentrating ability. Vasopressin V2 receptor binding capacity and mRNA expression were similar between the two groups, but the SIADH rats showed a diminished up-regulation of aquaporin-2 (AQP-2) mRNA and protein expression. These findings indicate the presence of tonicity-response regions in the AQP-2 promoter gene, and that either hypervolemia or hypotonicity may attenuate the postreceptor signalling of vasopressin in renal collecting duct cells in SIADH rats.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.0953-8194.2004.01177.x
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  • 9
    Digitale Medien
    Digitale Medien
    The effect of gravity on surface temperatures of plant leaves (2003)
    Oxford, UK : Blackwell Science Ltd
    Plant, cell & environment 26 (2003), S. 0 
    Details
    ISSN: 1365-3040
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: A fundamental study was conducted to develop a facility having an adequate air circulation system for growing healthy plants over a long-term under microgravity conditions in space. To clarify the effects of gravity on heat exchange between plant leaves and the ambient air, surface temperatures of sweet potato and barley leaves and replica leaves made of wet paper and copper were evaluated at gravity levels of 0.01, 1.0, 1.5 and 2.0 g for 20 s each during parabolic aeroplane flights. Thermal images were captured using infrared thermography at an air temperature of 26 °C, a relative humidity of 18% and an irradiance of 260 W  m−2. Mean leaf temperatures increased by 0.9–1.0 °C with decreasing gravity levels from 1.0 to 0.01 g and decreased by 0.5 °C with increasing gravity levels from 1.0 to 2.0 g. The increase in leaf temperatures was at most 1.9 °C for sweet potato leaves over 20 s as gravity decreased from 1.0 to 0.01 g. The boundary layer conductance to sensible heat exchange decreased by 5% when the gravity decreased from 1.0 to 0.01 g at the air velocity of 0.2 m s−1. The decrease in the boundary layer conductance with decrease in the gravity levels was more significant in a lower air velocity. Heat exchange between leaves and the ambient air was more retarded at lower gravity levels because of less sensible and latent heat transfers with less heat convection.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1365-3040.2003.00980.x
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  • 10
    Digitale Medien
    Digitale Medien
    Reversible decreases in the bulk elastic modulus of mature leaves of deciduous Quercus species subjected to two drought treatments (2004)
    Oxford, UK : Blackwell Science Ltd
    Plant, cell & environment 27 (2004), S. 0 
    Details
    ISSN: 1365-3040
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: Changes in leaf water relations under water stress were examined. In experiment 1, water stress was imposed by withholding irrigation to potted seedlings of deciduous oak, Quercus crispula and Q. serrata. Changes in the pressure–volume (P–V) curve in mature leaves were followed. The leaf water potential at turgor loss (Ψl,tlp) significantly decreased after 13 d of drought treatment. The bulk elastic modulus (ɛ) significantly decreased, which contributed to the maintenance of cell turgor together with the decrease in osmotic potential. In experiment 2, water stress was imposed by notching a branch of a Q. serrata tree. After the notching, the daily minimum leaf water potential (Ψl) decreased, and a significant decrease in Ψl,tlp was observed 15 d after notching. The osmotic potential at water saturation (Ψπ,sat) did not decrease significantly until 25 d after notching whereas, ɛ had already decreased significantly within 15 d after notching and increased promptly after substantial precipitation. It was confirmed that ɛ of mature leaves decreased reversibly in water stress. This response of ɛ was more rapid than that of the osmotic potential and, thus, effectively maintained cell turgor when water stress was suddenly imposed on the leaves.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1365-3040.2004.01192.x
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