Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Crystal structure and magnetism of LaCo13−x−yFexSiy compounds (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 336-341 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The crystal structure and magnetic properties of LaCo13−x−yFexSiy compounds were investigated by means of x-ray powder diffraction and magnetization measurements. The substitution of Si for Co induces an order–disorder transition from the cubic NaZn13-type to its tetragonal derivative structure, while the substitution of Fe for Co does not induce such a phase transition. After annealing treatment, the homogeneous range of the cubic phase is narrowed and that of the tetragonal phase is extended. From crystallographic and thermodynamic points of view, the sta- bility of the cubic and the tetragonal phases is discussed. The measured magnetic moment of LaCo13−x−yFexSiy coincides well with the theoretical prediction based on the magnetic valence model. Within the framework of this model, LaCo13−x−yFexSiy compounds can be considered as strong ferromagnets and their magnetic moment can be theoretically predicted. The composition dependence of Curie temperature is discussed within the mean field approximation. At higher iron concentration the decrease of Curie temperature with Fe concentration might be attributed to the increase of the number of antiferromagnetically coupled Fe–Fe pairs and the decrease of the ferromagnetic coupling between transition metal atoms. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362786
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Effect of cylindrical geometry on the wet thermal oxidation of AlAs (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 6901-6905 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have investigated the wet thermal oxidation of AlAs in cylindrical geometry, a typical configuration for vertical-cavity surface-emitting lasers. Through both experiment and theoretical calculations, we demonstrate a significantly different time dependence for circular mesas from what has been reported in the literature both in studies of stripes and in a study of circular mesas. We attribute this different time dependence to the effect of geometry on the oxidation. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.368987
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Near infrared avalanche photodiodes with bulk Al0.04Ga0.96Sb and GaSb/AlSb superlattice gain layers (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 4576-4579 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We demonstrate the use of bulk Al0.04Ga0.96Sb and GaSb/AlSb superlattice as the gain material in a separate absorption/multiplication avalanche photodiode with sensitivity up to 1.74 μm. Both gain schemes were implemented in a molecular-beam epitaxy grown structure with a selectively doped InAs/AlSb superlattice as the n-type layer. Hole impact ionization enhancement was observed in Al0.04Ga0.96Sb by using a two wavelength injection scheme. The superlattice gain layer device exhibited multiplication factors in excess of 300, and surface limited dark current at a level comparable to InGaAs/InAlAs devices of similar design. The superlattice gain layer was found to be more promising than its bulk counterpart due to its inherent lower dark current. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.371405
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Structure and Function of DNA Methyltransferases (1995)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Biophysics and Biomolecular Structure 24 (1995), S. 293-318 
    Details
    ISSN: 1056-8700
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.bb.24.060195.001453
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Giant magnetoresistance effect in bulk La1/3Nd1/3Ca1/3MnO3 at low field (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 424-426 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A magnetoresistance ratio as high as −96% in a low field of 0.67 T is achieved in bulk La1/3Nd1/3Ca1/3MnO3. The magnetization exhibits a transition from a low moment state to a high moment state with decreasing temperature, accompanied by a thermal hysteresis of the magnetization. The magnetic transition might be an order-order transition and would be responsible for the observed giant magnetoresistance effect in the compound at low field. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.118082
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Local tumor recurrence or emergence of a new primary lesion? A molecular analysis (1999)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of oral pathology & medicine 28 (1999), S. 0 
    Details
    ISSN: 1600-0714
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The distinction between a new primary oral tumor and recurrence may bear significant prognostic implications. Currently, this differentiation relies mainly on tumor location: when both lesions are at or near the same site, the new one is regarded as a recurrence; when the two are at different sites, the second lesion is regarded as a new primary. Recent investigations using molecular analysis have demonstrated that some oral squamous cell carcinomas (SCC) arising from different sites show the same clonogenical changes. In this case report, we studied the clonality of three SCC (one primary, two apparent recurrences) from the right lateral tongue of a young, non-smoking woman by using microsatellite analysis for loss of heterozygosity. The results showed that while the first two tumors were clonogenically similar, the third tumor was clonogenically different and was consistent with the development of a new primary. This result indicates that location of tumors alone is not always reliable in determining whether a new tumor is a recurrence or a new primary lesion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0714.1999.tb02058.x
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Cu-like Pd and Ag inner-shell photoionization phenomena (1996)
    Springer
    Applied physics 62 (1996), S. 619-622 
    Details
    ISSN: 1432-0649
    Keywords: 52.50.Jm ; 52.25.Nr
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We have obtained results for converting focused laser radiation to X-ray line emissions in laser-heated NaF and Cu plasmas. These plasmas were used as the pump source for studying the phenomena of inner-shell photoionization of Zn-like ionic states. Soft X-ray emissions from transitions of 3d 94s 2 → 3d 104p in Cu-like Pd and Ag ions were observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01081701
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Prevalence of Trabecular Microcallus Formation in the Vertebral Body and the Femoral Neck (1997)
    Springer
    Calcified tissue international 60 (1997), S. 479 -484 
    Details
    ISSN: 1432-0827
    Keywords: Key words: Trabecular microcallus formation — Vertebra — Femur — Histomorphometry — Bone density — Osteoporosis.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. Trabecular microcallus formation (TMF) has been described previously in the human vertebra and femur, but the difference in TMF prevalence at these two sites has not been studied and the role of TMF remains controversial. In this study, the 4th lumbar vertebra (L4) and right proximal femur were removed from 27 male and 23 female cadavers. A 2 cm cube cut from the center of L4 and a 1 cm-thick slice cut from the femoral neck were cleaned, defatted, and dried. The apparent density of the L4 cubes was determined as dry weight/bulk bone volume. Using a dissecting microscope at low magnification (4–60×), TMF were identified and counted in both the vertebral and femoral samples. A 8 mm diameter core was then cut from the center of the L4 cubes in the vertical direction, and selected histomorphometric parameters of the core were evaluated with an X-ray microcomputed tomography system (μ-CT). There was a significantly greater prevalence of TMF in vertebral cubes (82%) than in the femoral slices (11%) (P 〈 0.001). TMF prevalence did not differ significantly between males and females, but the mean number of TMF in the vertebra was significantly (P 〈 0.05) greater in females (15.0/vertebra) than in males (7.7/vertebra). In the vertebra, the majority of the observed TMF were in vertical trabeculae. Subjects over 60 years old had a higher TMF prevalence than those under 60 years old (P 〈 0.01). TMF numbers increased with decreasing apparent density (P 〈 0.05), whereas no significant correlations were found between TMF and bone volume (BV/TV), trabecular number (Tb.N), or trabecular thickness (Tb.Th) as assessed by μ-CT. In two fractured vertebra, very few TMFs (2 and 4, respectively) were observed. These results demonstrated that the occurrence of TMF is strongly related to the anatomical site, probably due to differences in the applied loads and the trabecular structure between sites. The results were consistent with the hypothesis that TMF is a mechanism acting to maintain bone strength, but further studies are needed to clarify this important issue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002239900266
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Radiological prevalence of lumbar intervertebral disc calcification in the elderly: an autopsy study (1996)
    Springer
    Skeletal radiology 25 (1996), S. 231-235 
    Details
    ISSN: 1432-2161
    Keywords: Key words Intervertebral disc calcification ; Osteoarthritis ; Radiographs ; Computed tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objective. The objective of this study was to investigate the in vitro radiological prevalence of lumbar intervertebral disc calcification (IDC) in the elderly and its relation to osteoarthritis (OA). Materials and methods. Lumbar spine segments comprising L2–4 were resected from 60 cadavers (30 males, 30 females; average age 67 years) and investigated with high-contrast radiography and computed tomography (CT). Results and conclusions. IDC was found in 58.3% of the patients using high-contrast radiography and in 46.7% of the patients using CT. IDC prevalence and OA grades in the lumbar spine and right hand were found to increase with age. IDC prevalence and OA grades for L2–3 were not significantly different from those for L3–4. No significant sex difference was found for IDC prevalence and OA grades. The results indicate that IDC is significantly underestimated in vivo by conventional radiography and that intervertebral disc calcification may be a common phenomenon in aging. The exact relation of IDC to OA remains undetermined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002560050070
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Factors Associated with Cortical and Trabecular Bone Loss as Quantified by Peripheral Computed Tomography (pQCT) at the Ultradistal Radius in Aging Women (1997)
    Springer
    Calcified tissue international 60 (1997), S. 164 -170 
    Details
    ISSN: 1432-0827
    Keywords: Key words: Peripheral quantitative computed tomography (pQCT) — Age-related bone loss — Growth hormone — IGF-I.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. Peripheral quantitative computed tomography (pQCT) allows the separate determination of cortical and trabecular bone mineral density in the peripheral skeleton. This cross-sectional study was designed to examine the effects of healthy aging on pQCT measurements at the ultradistal radius. In a well-defined sample of 129 community-based women, aged 70–87 years, the differences in cortical and trabecular density over the age range were equivalent to losses of −0.41% and −0.65% per year, respectively. To investigate the mechanism of this age-related decline, we assessed relationships between both parameters and height, weight, body mass index, dietary calcium intake, grip strength, and serum concentrations of insulin-like growth factor-I (IGF-I), calcidiol (25(OH)D3), calcitriol (1,25(OH)2D3), parathyroid hormone (PTH), and sex hormone binding globulin (SHBG). Multiple regression was used to adjust for potential confounders. Age was not significant after controlling for other covariables. Body mass index, grip strength, serum IGF-I, 25(OH)D3, and PTH (1–84) were found to be independent predictors of total bone density. Including (total or free) 1,25(OH)2D3 did not improve the model precision. These findings provide evidence that, among other factors, the activity of the growth hormone-IGF-I-axis is of importance for skeletal integrity. Grip strength, serum IGF-I, and PTH (1–84) were discovered to be significantly related to cortical but not to trabecular density, suggesting that different mechanisms may be involved in compact and cancellous bone loss.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002239900208
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...