| 131. |
- Nakamura, Keisuke, et al.
(författare)
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Effect of low-temperature degradation on the mechanical and microstructural properties of tooth-colored 3Y-TZP ceramics
- 2016
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Ingår i: Journal of The Mechanical Behavior of Biomedical Materials. - : Elsevier BV. - 1751-6161 .- 1878-0180. ; 53, s. 301-311
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to evaluate the effects of low-temperature degradation (LTD) induced by autoclaving on the mechanical and microstructural properties of tooth-colored 3mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP). In total, 162 disc-shaped 3Y-TZP specimens were prepared. Two-thirds of the specimens were shaded by either the infiltration or powder mixing methods while the remaining specimens were used without coloring. The specimens were autoclaved at 134°C for 0, 10, and 100h to induce LTD (n=18 for each group). Chemical compositions were analyzed with X-ray fluorescence spectroscopy. Biaxial flexural strength was measured using a piston-on-three-ball test. The surface fraction and penetration depth of the monoclinic phase were examined using X-ray diffraction and scanning electron microscopy, respectively. The tooth-colored 3Y-TZP specimens contained Fe2O3 and Er2O3 (infiltration technique), and Fe2O3 (powder mixing method) at concentrations of<0.5wt%. The tooth-colored 3Y-TZP had higher strength than the non-colored material after 100h of autoclaving. In terms of surface fraction and penetration depth, the generation of monoclinic phase was significantly lower in the tooth-colored 3Y-TZP than in the non-colored material. The tooth-colored 3Y-TZP possessed equivalent biaxial flexural strength to that of the non-colored material and higher resistance to LTD regardless of the coloring technique (infiltration technique or powder mixing method) when the coloring pigments were contained at concentrations used in the present study. © 2015 Elsevier Ltd.
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| 132. |
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| 133. |
- Ono, M, et al.
(författare)
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Signal transducer and activator of transcription (Stat) 5b-mediated inhibition of insulin-like growth factor binding protein-1 gene transcription: a mechanism for repression of gene expression by growth hormone
- 2007
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Ingår i: Molecular endocrinology (Baltimore, Md.). - : The Endocrine Society. - 0888-8809 .- 1944-9917. ; 21:6, s. 1443-1457
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Tidskriftsartikel (refereegranskat)abstract
- GH plays a central role in controlling somatic growth, tissue regeneration, and intermediary metabolism in most vertebrate species through mechanisms dependent on the regulation of gene expression. Recent studies using transcript profiling have identified large cohorts of genes whose expression is induced by GH. Other results have demonstrated that signal transducer and activator of transcription (Stat) 5b, a latent transcription factor activated by the GH receptor-associated protein kinase, Jak2, is a key agent in the GH-stimulated gene activation that leads to somatic growth. By contrast, little is known about the steps through which GH-initiated signaling pathways reduce gene expression. Here we show that Stat5b plays a critical role in the GH-regulated inhibition of IGF binding protein-1 gene transcription by impairing the actions of the FoxO1 transcription factor on the IGF binding protein-1 promoter. Additional observations using transcript profiling in the liver indicate that Stat5b may be a general mediator of GH-initiated gene repression. Our results provide a model for understanding how GH may simultaneously stimulate and inhibit the expression of different cohorts of genes via the same transcription factor, potentially explaining how GH action leads to integrated biological responses in the whole organism.
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| 134. |
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| 135. |
- Ono, SF, et al.
(författare)
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Air-breathing behavior underlies the cell death in limbs of Rana pirica tadpoles
- 2023
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Ingår i: Zoological letters. - : Springer Science and Business Media LLC. - 2056-306X. ; 9:1, s. 2-
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Tidskriftsartikel (refereegranskat)abstract
- Amphibians shape their limbs by differential outgrowth of digits and interdigital regions. In contrast, amniotes employ cell death, an additional developmental system, to determine the final shape of limbs. Previous work has shown that high oxygen availability is correlated with the induction of cell death in developing limbs. Given the diversity of life histories of amphibians, it is conceivable that some amphibians are exposed to a high–oxygen environment during the tadpole phase and exhibit cell death in their limbs. Here, we examined whether air–breathing behavior underlies the cell death in limbs of aquatic tadpoles of the frog species Rana pirica. Our experimental approach revealed that R. pirica tadpoles exhibit cell death in their limbs that is likely to be induced by oxidative stress associated with their frequent air–breathing behavior.
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| 136. |
- Rivera-Cuevas, Yolanda, et al.
(författare)
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Toxoplasma gondii exploits the host ESCRT machinery for parasite uptake of host cytosolic proteins
- 2021
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Ingår i: PLoS Pathogens. - : Public Library of Science (PLoS). - 1553-7366 .- 1553-7374. ; 17:12, s. e1010138-e1010138
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Tidskriftsartikel (refereegranskat)abstract
- Toxoplasma gondii is a master manipulator capable of effectively siphoning the resources from the host cell for its intracellular subsistence. However, the molecular underpinnings of how the parasite gains resources from its host remain largely unknown. Residing within a non-fusogenic parasitophorous vacuole (PV), the parasite must acquire resources across the limiting membrane of its replicative niche, which is decorated with parasite proteins including those secreted from dense granules. We discovered a role for the host Endosomal Sorting Complex Required for Transport (ESCRT) machinery in host cytosolic protein uptake by T. gondii by disrupting host ESCRT function. We identified the transmembrane dense granule protein TgGRA14, which contains motifs homologous to the late domain motifs of HIV-1 Gag, as a candidate for the recruitment of the host ESCRT machinery to the PV membrane. Using an HIV-1 virus-like particle (VLP) release assay, we found that the motif-containing portion of TgGRA14 is sufficient to substitute for HIV-1 Gag late domain to mediate ESCRT-dependent VLP budding. We also show that TgGRA14 is proximal to and interacts with host ESCRT components and other dense granule proteins during infection. Furthermore, analysis of TgGRA14-deficient parasites revealed a marked reduction in ingestion of a host cytosolic protein compared to WT parasites. Thus, we propose a model in which T. gondii recruits the host ESCRT machinery to the PV where it can interact with TgGRA14 for the internalization of host cytosolic proteins across the PV membrane (PVM). These findings provide new insight into how T. gondii accesses contents of the host cytosol by exploiting a key pathway for vesicular budding and membrane scission.
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| 137. |
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| 138. |
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| 139. |
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| 140. |
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