280 research outputs found

    Crystal structure, electrical properties, and mechanical response of (100)-/(001)-oriented epitaxial Pb(Mg1/3Nb2/3)O 3-PbTiO3 films grown on (100)cSrRuO 3∥(100)SrTiO3 substrates by metal-organic chemical vapor deposition

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    Relaxor-type ferroelectric (1-x)Pb(Mg1/3Nb2/3)O 3-xPbTiO3 (PMN-PT) films, 2-3 μm in thickness, with a PbTiO3 content (x) ranging from 0 to 1 were grown on (100) cSrRuO3∥(100)SrTiO3 substrates at 650°C by metal-organic chemical vapor deposition. The effects the x value had on the crystal structure, dielectric and ferroelectric properties, and mechanical response of these films were systematically investigated. Epitaxial growth having (100)/(001) orientation irrespective of x and the constituent phase change with x were ascertained from both x-ray diffraction reciprocal space mapping analysis and Raman spectroscopy. The constituent phase changed from a rhombohedral (pseudocubic) single phase, a mixture phase of rhombohedral (pseudocubic) and tetragonal phases, and a tetragonal single phase, with increasing x. The mixed phase region was found to exist at x=0.40-0.55, which was different from that reported for single crystals (x=0.31-0.35). The dependencies of relative dielectric constant and remanent polarization on x showed a similar trend in the case of a PMN-PT sintered body; however, the magnitudes of these values were relatively low. The effective longitudinal piezoelectric coefficient (d33,f) and the transverse coefficient (e31,f) of 100-120 pm/V and ∼-11.0 C/m2 were, respectively, calculated for a film with x=0.39, which corresponds to a larger x edge for the rhombohedral (pseudocubic) region following the engineered domain concept proposed for PMN-PT single crystals

    Lattice-patterned collagen fibers and their dynamics in axolotl skin regeneration

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    The morphology of collagen-producing cells and the structure of produced collagen in the dermis have not been well-described. This lack of insights has been a serious obstacle in the evaluation of skin regeneration. We succeeded in visualizing collagen-producing cells and produced collagen using the axolotl skin, which is highly transparent. The visualized dermal collagen had a lattice-like structure. The collagen-producing fibroblasts consistently possessed the lattice-patterned filopodia along with the lattice-patterned collagen network. The dynamics of this lattice-like structure were also verified in the skin regeneration process of axolotls, and it was found that the correct lattice-like structure was not reorganized after simple skin wounding but was reorganized in the presence of nerves. These findings are not only fundamental insights in dermatology but also valuable insights into the mechanism of skin regeneration

    The Erotic and the Vulgar: Visual Culture and Organized Labor's Critique of U.S. Hegemony in Occupied Japan

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    This essay engages the colonial legacy of postwar Japan by arguing that the political cartoons produced as part of the postwar Japanese labor movement’s critique of U.S. cultural hegemony illustrate how gendered discourses underpinned, and sometimes undermined, the ideologies formally represented by visual artists and the organizations that funded them. A significant component of organized labor’s propaganda rested on a corpus of visual media that depicted women as icons of Japanese national culture. Japan’s most militant labor unions were propagating anti-imperialist discourses that invoked an engendered/endangered nation that accentuated the importance of union roles for men by subordinating, then eliminating, union roles for women

    The ADAMTS (A Disintegrin and Metalloproteinase with Thrombospondin motifs) family

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    The ADAMTS (A Disintegrin and Metalloproteinase with Thrombospondin motifs) enzymes are secreted, multi-domain matrix-associated zinc metalloendopeptidases that have diverse roles in tissue morphogenesis and patho-physiological remodeling, in inflammation and in vascular biology. The human family includes 19 members that can be sub-grouped on the basis of their known substrates, namely the aggrecanases or proteoglycanases (ADAMTS1, 4, 5, 8, 9, 15 and 20), the procollagen N-propeptidases (ADAMTS2, 3 and 14), the cartilage oligomeric matrix protein-cleaving enzymes (ADAMTS7 and 12), the von-Willebrand Factor proteinase (ADAMTS13) and a group of orphan enzymes (ADAMTS6, 10, 16, 17, 18 and 19). Control of the structure and function of the extracellular matrix (ECM) is a central theme of the biology of the ADAMTS, as exemplified by the actions of the procollagen-N-propeptidases in collagen fibril assembly and of the aggrecanases in the cleavage or modification of ECM proteoglycans. Defects in certain family members give rise to inherited genetic disorders, while the aberrant expression or function of others is associated with arthritis, cancer and cardiovascular disease. In particular, ADAMTS4 and 5 have emerged as therapeutic targets in arthritis. Multiple ADAMTSs from different sub-groupings exert either positive or negative effects on tumorigenesis and metastasis, with both metalloproteinase-dependent and -independent actions known to occur. The basic ADAMTS structure comprises a metalloproteinase catalytic domain and a carboxy-terminal ancillary domain, the latter determining substrate specificity and the localization of the protease and its interaction partners; ancillary domains probably also have independent biological functions. Focusing primarily on the aggrecanases and proteoglycanases, this review provides a perspective on the evolution of the ADAMTS family, their links with developmental and disease mechanisms, and key questions for the future

    Betacellulin Induces Increased Retinal Vascular Permeability in Mice

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    BACKGROUND: Diabetic maculopathy, the leading cause of vision loss in patients with type 2 diabetes, is characterized by hyper-permeability of retinal blood vessels with subsequent formation of macular edema and hard exudates. The degree of hyperglycemia and duration of diabetes have been suggested to be good predictors of retinal complications. Intervention studies have determined that while intensive treatment of diabetes reduced the development of proliferative diabetic retinopathy it was associated with a two to three-fold increased risk of severe hypoglycemia. Thus we hypothesized the need to identify downstream glycemic targets, which induce retinal vascular permeability that could be targeted therapeutically without the additional risks associated with intensive treatment of the hyperglycemia. Betacellulin is a 32 kD member of the epidermal growth factor family with mitogenic properties for the retinal pigment epithelial cells. This led us to hypothesize a role for betacellulin in the retinal vascular complications associated with diabetes. METHODS AND FINDINGS: In this study, using a mouse model of diabetes, we demonstrate that diabetic mice have accentuated retinal vascular permeability with a concomitant increased expression of a cleaved soluble form of betacellulin (s-Btc) in the retina. Intravitreal injection of soluble betacellulin induced retinal vascular permeability in normoglycemic and hyperglycemic mice. Western blot analysis of retinas from patients with diabetic retinopathy showed an increase in the active soluble form of betacellulin. In addition, an increase in the levels of A disintegrin and metalloproteinase (ADAM)-10 which plays a role in the cleavage of betacellulin was seen in the retinas of diabetic mice and humans. CONCLUSIONS: These results suggest that excessive amounts of betacellulin in the retina may contribute to the pathogenesis of diabetic macular edema

    Overexpression of Myocilin in the Drosophila Eye Activates the Unfolded Protein Response: Implications for Glaucoma

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    Glaucoma is the world's second leading cause of bilateral blindness with progressive loss of vision due to retinal ganglion cell death. Myocilin has been associated with congenital glaucoma and 2-4% of primary open angle glaucoma (POAG) cases, but the pathogenic mechanisms remain largely unknown. Among several hypotheses, activation of the unfolded protein response (UPR) has emerged as a possible disease mechanism.We used a transgenic Drosophila model to analyze whole-genome transcriptional profiles in flies that express human wild-type or mutant MYOC in their eyes. The transgenic flies display ocular fluid discharge, reflecting ocular hypertension, and a progressive decline in their behavioral responses to light. Transcriptional analysis shows that genes associated with the UPR, ubiquitination, and proteolysis, as well as metabolism of reactive oxygen species and photoreceptor activity undergo altered transcriptional regulation. Following up on the results from these transcriptional analyses, we used immunoblots to demonstrate the formation of MYOC aggregates and showed that the formation of such aggregates leads to induction of the UPR, as evident from activation of the fluorescent UPR marker, xbp1-EGFP. CONCLUSIONS / SIGNIFICANCE: Our results show that aggregation of MYOC in the endoplasmic reticulum activates the UPR, an evolutionarily conserved stress pathway that culminates in apoptosis. We infer from the Drosophila model that MYOC-associated ocular hypertension in the human eye may result from aggregation of MYOC and induction of the UPR in trabecular meshwork cells. This process could occur at a late age with wild-type MYOC, but might be accelerated by MYOC mutants to account for juvenile onset glaucoma
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