113 research outputs found
DKK3 (dickkopf 3 homolog (Xenopus laevis))
Review on DKK3 (dickkopf 3 homolog (Xenopus laevis)), with data on DNA, on the protein encoded, and where the gene is implicated
Differential expression of basement membrane collagen-IV alpha l to alpha 6 chains during oral carcinogenes
This study aimed to resolve if basement membrane (BM) collagen alpha chains undergo remodeling during oral. carcinogenesis. Using immunohistochemistry and transmission electron microscopy, we found that BMs in oral epithelial dysplasias (OED: mild, n=10; moderate, n=10; severe, n=10) and carcinoma in situ (CIS) (n=10) differed from normal mucosa (n=6) and oral epithelial hyperplasia (n=5) in showing: (1) excessive lamina densa-like material ultrastructurally, and (2) stronger immunoexpression for alpha 5(IV) than for alpha 1(IV), alpha 2(IV), and alpha 6(IV) chains-findings that implicate these molecules' role as an adhesive template for the attachment and persistence of basal dysplastic cells. Incipient loss of BM integrity in CIS, where alpha 5(IV)/alpha 6(IV) chains were more frequently absent than alpha 1(IV)/alpha 2(IV) chains, suggests that alpha(IV) network disruption is crucial for progression of dysplastic cells into the extracellular compartment, marking transition into the invasive phase. In carcinomatous BM, the disappearance of alpha(IV) chains was more severe in poorly differentiated oral squamous cell carcinoma (OSCC) (n=10) than in well-differentiated OSCC (n=10). In all samples examined, alpha 3(IV) and alpha 4(IV) chains were absent. These findings taken together suggest that BM collagen-IV alpha chains undergo remodeling where selective increase and loss of these molecules are probably early and late events, respectively, during progression of oral dysplasia to cancer. This record was migrated from the OpenDepot repository service in June, 2017 before shutting down
NRAS and BRAF mutation frequency in primary oral mucosal melanoma
Oral mucosal melanoma (OMM) is a fatal sarcoma of unknown etiology. Histological morphology and genetic events are distinct from those of its cutaneous counterpart. Mutation and up-regulation of c-kit has been identified in OMM which may activate downstream molecules such as RAS and RAF. These molecules are involved in the mitogen-activated protein kinase (MAPK) pathway leading to tremendous cell proliferation and survival. NRAS and BRAF mutation and protein expression have been studied in other melanoma subtypes. The purpose of this study was to determine RAS protein expression and NRAS and BRAF mutation in 18 primary OMM cases using immunohistochemistry and mutation analysis. Results showed that RAS is intensely expressed in both in situ and invasive OMMs. However, NRAS mutation was only observed in 2/15 polymerase chain reaction (PCR) amplified cases both of which were silent mutations. On the other hand, BRAF missense mutations were observed only in 1/15 cases with PCR amplification. NRAS and BRAF mutations were independent from previously reported c-kit mutations. The classical V600E BRAF mutation was not found; instead a novel V600L was observed suggesting that the oncogenic event in OMM is different from that in skin melanoma. The low frequency of NRAS and BRAF mutations indicate that these genes are not common, but probable events in OMM pathogenesis, most likely independent of c-kit mutation. This record was migrated from the OpenDepot repository service in June, 2017 before shutting down
Epitaxial growth and anisotropy of La(O,F)FeAs thin films deposited by Pulsed Laser Deposition
LaFeAsO1-xFx thin films were deposited successfully on (001)-oriented LaAlO3
and MgO substrates from stoichiometric LaFeAsO1-xFx polycrystalline targets
with fluorine concentrations up to x = 0.25 by PLD. Room temperature deposition
and post annealing of the films yield nearly phase pure films with a pronounced
c-axis texture and a strong biaxial in-plane orientation. Transport
measurements show metallic resistance and onset of superconductivity at 11 K.
Hc2(T) was determined by resistive measurements and yield Hc2 values of 3 T at
3.6 K for B||c and 6 T at 6.4 K for B||ab.Comment: 11 pages, 5 figure
Thin Film Growth and Device Fabrication of Iron-Based Superconductors
Iron-based superconductors have received much attention as a new family of
high-temperature superconductors owing to their unique properties and distinct
differences from cuprates and conventional superconductors. This paper reviews
progress in thin film research on iron-based superconductors since their
discovery for each of five material systems with an emphasis on growth,
physical properties, device fabrication, and relevant bulk material properties.Comment: To appear in J. Phys. Soc. Jp
Ultralow-dissipative conductivity by Dirac fermions in BaFeAs
We report on the anomalous behavior of the complex conductivity of
BaFeAs, which is related to the Dirac cone, in the terahertz
(THz)-frequency region. Above the spin-density-wave (SDW) transition
temperature, the conductivity spectra follow the Drude model. In the SDW state,
the imaginary part of the complex conductivity, , is suppressed in
comparison to that expected according to the Drude model. The real part,
, exhibits nearly Drude-like behavior. This behavior (i.e., almost no
changes in and the depression of ) can be regarded as the
addition of extra conductivity without any dissipations in the Drude-type
conductivity. The origin of this ultralow-dissipative conductivity is found to
be due to conductivity contribution from quasiparticles within the Dirac cone.
In other words, we are able to observe the dynamics of Dirac fermions through
the conductivity spectra of BaFeAs, clearly and directly.Comment: 5pages, 3 figure
Spectroscopic scanning tunneling microscopy insights into Fe-based superconductors
In the first three years since the discovery of Fe-based high Tc
superconductors, scanning tunneling microscopy (STM) and spectroscopy have shed
light on three important questions. First, STM has demonstrated the complexity
of the pairing symmetry in Fe-based materials. Phase-sensitive quasiparticle
interference (QPI) imaging and low temperature spectroscopy have shown that the
pairing order parameter varies from nodal to nodeless s\pm within a single
family, FeTe1-xSex. Second, STM has imaged C4 -> C2 symmetry breaking in the
electronic states of both parent and superconducting materials. As a local
probe, STM is in a strong position to understand the interactions between these
broken symmetry states and superconductivity. Finally, STM has been used to
image the vortex state, giving insights into the technical problem of vortex
pinning, and the fundamental problem of the competing states introduced when
superconductivity is locally quenched by a magnetic field. Here we give a
pedagogical introduction to STM and QPI imaging, discuss the specific
challenges associated with extracting bulk properties from the study of
surfaces, and report on progress made in understanding Fe-based superconductors
using STM techniques.Comment: 36 pages, 23 figures, 229 reference
A pigmented calcifying cystic odontogenic tumor associated with compound odontoma: a case report and review of literature
<p>Abstract</p> <p>Background</p> <p>Pigmented intraosseous odontogenic lesions are rare with only 47 reported cases in the English literature. Among them, pigmented calcifying cystic odontogenic tumor, formerly known as calcifying odontogenic cyst, is the most common lesion with 20 reported cases.</p> <p>Methods</p> <p>A case of pigmented calcifying cystic odontogenic tumor associated with odontoma occurring at the mandibular canine-premolar region of a young Japanese boy is presented with radiographic, and histological findings. Special staining, electron microscopic study and immunohistochemical staining were also done to characterize the pigmentation.</p> <p>Results</p> <p>The pigments in the lesion were confirmed to be melanin by Masson-Fontana staining and by transmission electron microscopy. The presence of dendritic melanocytes within the lesion was also demonstrated by S-100 immunostaining.</p> <p>Conclusion</p> <p>The present case report of pigmented calcifying cystic odontogenic tumor associated with odontoma features a comprehensive study on melanin and melanocytes, including histochemical, immunohistochemical and transmission electron microscopic findings.</p
Photoinduced transient states of antiferromagnetic orderings in La1 3Sr2 3FeO3 and SrFeO3 delta thin films observed through time resolved resonant soft x ray scattering
The relationship between the magnetic interaction and photoinduced dynamics in antiferromagnetic perovskites is investigated in this study. In La1 3Sr2 3FeO3 thin films, commensurate spin ordering is accompanied by charge disproportionation, whereas SrFeO3 amp; 8722; amp; 948; thin films show incommensurate helical antiferromagnetic spin ordering due to increased ferromagnetic coupling compared to La1 3Sr2 3FeO3. To understand the photoinduced spin dynamics in these materials, we investigate the spin ordering through time resolved resonant soft x ray scattering. In La1 3Sr2 3FeO3, ultrafast quenching of the magnetic ordering within 130 fs through a nonthermal process is observed, triggered by charge transfer between the Fe atoms. We compare this to the photoinduced dynamics of the helical magnetic ordering of SrFeO3 amp; 8722; amp; 948;. We find that the change in the magnetic coupling through optically induced charge transfer can offer an even more efficient channel for spin order manipulatio
To use or not to use cool superconductors?
The high critical temperature and magnetic field in cuprates and Fe-based
superconductors are not enough to assure applications at higher temperatures.
Making these superconductors useful involves complex and expensive technologies
to address many conflicting physics and materials requirements
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