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  • 1
    Electronic Resource
    Electronic Resource
    Evidence for valence fluctuation of Fe in Sr2FeMoO6−w double perovskite (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 2925-2927 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In this letter evidence for the formation of a valence-fluctuation state of iron, formally denoted as Fe2.5+, is presented. The system under study is the Sr2FeMoO6−w double perovskite, known for exhibiting a very large magnetoresistance. Samples of Sr2FeMoO6−w were synthesized by means of an encapsulation technique utilizing an Fe getter technique and characterized by 57Fe Mössbauer spectroscopy. From 5 K to room temperature the Mössbauer spectrum is dominated by a component with hyperfine parameter values between those expected for high-spin Fe3+ and high-spin Fe2+. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.126518
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  • 2
    Electronic Resource
    Electronic Resource
    A Monte Carlo study of the pattern formation during transitions in n-alkane crystals (2000)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 112 (2000), S. 7627-7633 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The rotator phase transition in n-alkane was recently found to show a characteristic pattern of preferred growth along the b-axis (shorter axis) of the unit cell. In order to investigate the origin of this anisotropic growth, a pattern formation in n-alkane crystal is studied during the transition between the low temperature orthorhombic (LO) phase and the rotator (R) phase by use of the Monte Carlo method. Of possible factors that will influence the growth pattern, we here concentrate on the mode of chain packing by assuming that the chains have rigid planar zigzag conformation and are placed in a regular orthohexagonal lattice. The herringbone order in the LO phase is found to develop rather quickly resulting characteristic domains with the (100) and (110) boundaries. The domain boundaries run preferentially along the b-axis at lower temperatures and are considered as a stacking fault or antiphase boundary. The transition between the LO phase and the R phase is found to exhibit a characteristic pattern, where the R phase domains grow preferentially along the b-axis. All these behaviors are shown to originate from different energies of the (100) and (110) boundaries. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.481357
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  • 3
    Electronic Resource
    Electronic Resource
    The fibrous structure of the cemento–dentinal junction in human molars shown by scanning electron microscopy combined with NaOH-maceration (2000)
    Copenhagen : Munksgaard International Publishers
    Journal of periodontal research 35 (2000), S. 0 
    Details
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The cemento–dentinal junction was studied in acellular and cellular cementum of human mandibular third molars by scanning electron microscopy combined with NaOH-maceration. Scanning electron microscopy with NaOH-maceration was applied to observe the fibrous structure in detail through long sections of the cemento–dentinal junction. In macerated specimens, the cemento–dentinal junction was a fibril-poor groove. Some cemental fibrils or fibril bundles penetrated the groove and appeared to intermingle with dentinal fibrils. Prolonged maceration caused detachment of the cemento–dentinal junction irrespective of fibril intermingling allowing observation of the inner cementum surface facing the root dentin. Observations suggested that the fibril intermingling was point-like and present only in places at the cemento–dentinal junction. It was established that NaOH-maceration removes interfibrillar substances effectively in connective tissues and does no damage to the collagen fibril structure and architecture. This study showed the 3-dimensional fibrous structure of the cemento–dentinal junction in human mandibular third molars, and suggested that interfibrillar adhesive substances are more important than the fibril intermingling for the cemento–dentinal attachment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1600-0765.2000.035002059.x
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  • 4
    Electronic Resource
    Electronic Resource
    Light and electron microscopic study of the initial attachment of principal fibers to the alveolar bone surface in rat molars (2000)
    Copenhagen : Munksgaard International Publishers
    Journal of periodontal research 35 (2000), S. 0 
    Details
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: This study was designed to observe the principal fibers and alveolar bone in various developmental stages in rat molars using light and transmission electron microscopy and to elucidate the mechanism of initial principal fiber attachment to the alveolar bone surface. Maxillary alveolar bone between the 2nd and 3rd molars of 20- and 25-day-old rats was used. A proteoglycan-rich, fiber-poor, and electron dense layer formed on the alveolar bone surface before the principal fiber organization. This layer was not seen before principal fibers had started to develop. Principal fibers first contacted and then became embedded in this layer. With further development, new bone deposited on this layer and around already attached principal fibers. These findings suggest that this electron dense, proteoglycan-rich layer may act as an adhesive factor to mediate the initial attachment of principal fibers to the alveolar bone surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1600-0765.2000.035006344.x
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  • 5
    Electronic Resource
    Electronic Resource
    The fibrillar structure of cement lines on resorbed root surfaces of human teeth (2000)
    Copenhagen : Munksgaard International Publishers
    Journal of periodontal research 35 (2000), S. 0 
    Details
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The cement lines between reparative cementum and resorbed dentin or cementum in human teeth were observed by light microscopy and scanning electron microscopy combined with NaOH maceration. The NaOH maceration was used to remove interfibrillar substances and to observe the fibrillar architecture of the cement lines directly. Light microscopy showed that the cement lines were rich in proteoglycans with mucopolysaccharides, but deficient in collagen fibrils. The cement lines were artificially broken after treatment with hyaluronidase, which digests some of the mucopolysaccharides, but digests no collagen fibrils. Scanning electron microscopy showed that fibril intermingling occurred only in some places between reparative cementum and resorbed tissue. These findings suggested that the proteoglycans in cement lines mediate the attachment between new and old mineralized tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1600-0765.2000.035004208.x
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  • 6
    Electronic Resource
    Electronic Resource
    Neuromagnetic assessment of epileptogenicity in cerebral arteriovenous malformation (2000)
    Springer
    Neurosurgical review 23 (2000), S. 206-212 
    Details
    ISSN: 1437-2320
    Keywords: Keywords Arteriovenous malformation ; Magnetoencephalography ; Magnetic source imaging ; Electrocorticography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Magnetoencephalographic (MEG) activities were recorded in five patients with cerebral arteriovenous malformation (AVM) who presented with epilepsy and no clinical history of intracranial hemorrhage, using a 37-channel DC superconducting quantum interference device (SQUID) system. While scalp-recorded electroencephalograms (EEG) failed to reveal paroxysmal discharge, MEGs demonstrated localized high frequency magnetic activity (HFMA). Magnetic source imaging (MSI) depicted the accumulation of equivalent current dipole (ECD) originating from HFMA around the nidus, and the ECD localization agreed well with spike localization on intraoperative electrocorticography (ECoG). These areas corresponded with the areas of hypoperfusion on single photon emission tomography and the intraoperative laser Doppler flow meter. We discussed the application of MEG in estimating interictal paroxysmal activity sources in patients with AVM and addressed the questions of its reliability and validity in source localization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00011956
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  • 7
    Electronic Resource
    Electronic Resource
    Twisted plywood structure of an alternating lamellar pattern in cellular cementum of human teeth (2000)
    Springer
    Anatomy and embryology 202 (2000), S. 25-30 
    Details
    ISSN: 1432-0568
    Keywords: Keywords Cementoblasts ; Collagen fibrils ; Lamellar structure ; Maceration ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Human cellular cementum was examined by scanning electron microscopy to elucidate the manner of the alternate lamellar pattern forming the cellular cementum. Specimens were demineralized, trimmed with a freezing microtome, and treated by NaOH-maceration. This procedure was chosen to avoid artifacts in the fibril arrangement, and to study the fibrous architecture in detail. For comparison, non-demineralized, polished and HCl-etched specimens were also prepared. In the NaOH-macerated specimens, the lamellar pattern of the cellular cementum conformed to the twisted plywood principle of bone lamellation with a periodic rotation of matrix fibrils resulting in an alternating lamellar pattern. In contrast, matrix fibrils were irregularly arranged without indication of rotation of matrix fibrils in the polished and etched specimens. Our results suggest that polishing and etching procedures cause damage to fibrils and fibril arrangement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00008241
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  • 8
    Electronic Resource
    Electronic Resource
    Welding Phenomena of Aluminum-Copper Alloy in Electron Beam Welding (2000)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 331-337 (May 2000), p. 1763-1768 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/04/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.331-337.1763.pdf
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  • 9
    Electronic Resource
    Electronic Resource
    Blunted effect of parathyroid hormone on adenosine 3′,5′-cyclic monophosphate production is derived from ATP depletion in proximal convoluted tubules of hypophosphatemic mice (2000)
    Springer
    Clinical and experimental nephrology 4 (2000), S. 11-17 
    Details
    ISSN: 1437-7799
    Keywords: Key words Extracellular phosphate ; Hypophosphatemic mice ; Adenosine 3′,5′-cyclic monophosphate ; Parathyroid hormone ; X-linked hypophosphatemic rickets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background. To clarify the pathophysiological features associated with phosphate depletion in hypophosphatemic (Hyp) mice, we examined the effect of extracellular phosphate on parathyroid hormone (PTH)-stimulated adenosine 3′,5′-cyclic monophosphate (cAMP) production in the proximal convoluted tubules (PCT). Methods. PTH-Stimulated cAMP production and ATP content were determined by radioimmunoassay and luciferin-luciferase chemiluminescence methods, respectively. Results. The level of cAMP stimulated by PTH at an extracellular phosphate concentration of 0.78 mM was lower in the Hyp mice than in normal mice. The PTH-stimulated cAMP production in the Hyp mice was increased when the extracellular phosphate concentration was raised. In contrast, an increase in extracellular phosphate did not affect the PTH-stimulated cAMP production in the normal mice. Although the ATP content of the PCT was not different between the normal and Hyp mice immediately after microdissection, after 60 min of incubation, it had decreased to a greater extent in Hyp mice than in the normal animals. Raising the extracellular phosphate concentration from 0.78 to 2.3 mM prevented the decrease in ATP content in Hyp mice, and the intracellular ATP content then became comparable to that in the normal control. Conclusions. These results suggest that ATP content in the PCT tended to be decreased in Hyp mice by a decreased phosphate supply and that the blunted effect of PTH on cAMP production in these mice is due to ATP depletion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s101570050055
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  • 10
    Electronic Resource
    Electronic Resource
    A scanning electron microscope study on the effects of different bile salts on the epithelial lining of jejunal mucosa (2000)
    Springer
    Medical electron microscopy 33 (2000), S. 11-15 
    Details
    ISSN: 1437-773X
    Keywords: Key words Scanning electron microscopy ; Bile salts ; Crack formation ; Denudation ; Jejunal mucosa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Deconjugation of bile salts may occur in the jejunum under conditions of bacterial proliferation in the upper small intestine. We studied the morphological changes of jejunal mucosa induced by different conjugated (taurocholate, taurodeoxycholate, taurochenodeoxycholate, tauroursodeoxycholate) and unconjugated (cholate, deoxycholate, chenodeoxycholate, ursodeoxycholate) bile salts as compared by scanning electron microscopy. The epithelial lining of the jejunum was not affected in structural appearance below 40 mM concentration of the conjugated bile salts examined. On the other hand, the unconjugated bile salts examined induced morphological changes in varying degree and severity from crack formation at the tip to complete denudation of the jejunal villi, depending on the kind and dose of bile salts given. Among the unconjugated bile salts examined, the most robust in action was deoxycholate, which induced crack formation at 1.0 mM concentration, and the weakest was cholate. The study suggests that deconjugated bile salts produced by bacterial overgrowth in the upper small intestine can induce breakdown of the junctional integrity of the epithelial lining in varying degree and severity, ultimately leading to exfoliation of the epithelium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s007950000002
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