An atomic resolution study of a carbide phase in platinum

Under normal circumstances, Pt dissolves only a very small amount of interstitial carbon in solid solution. Even so, an appropriate quench/age treatment leads to the formation of stable Pt2C {100} plate precipitates. Excess (quenched-in) vacancies play a critical role in the process by accommodating the volume and structural changes that accompany the transformation. This alloy system exhibits other interesting properties. Due to a large vacancy/carbon atom binding energy, Pt can absorb excess carbon at high temperatures in a carburizing atmosphere. In regions rich in carbon and vacancies, another carbide phase, Pt7C which undergoes an order-disorder reaction was formed. The present study of Pt carburized at 1160°C and aged at 515°C shows that other carbides in the PtxC series can be produced.

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Structural Changes in Cobalt Solid-Solution Crystals Due to Milling

Practical Metallography ◽

10.3139/147.110195 ◽

2012 ◽

Vol 49 (11) ◽

pp. 683-696

Author(s):

H. Podlesak ◽

C. Gläser ◽

B. Wielage ◽

D. Hösel ◽

R. Neugebauer

Keyword(s):

Solid Solution ◽

Structural Changes

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Strength, Hardness, and Ductility Evidence of Solid Solution Strengthening and Limited Hydrogen Embrittlement in the Alloy System Palladium-Copper (Cu wt. % 5–25)

Hydrogen ◽

10.3390/hydrogen2030014 ◽

2021 ◽

Vol 2 (3) ◽

pp. 262-272

Author(s):

Sebastian DiMauro ◽

Gabrielle Legall ◽

Coleman Lubinsky ◽

Monica Nadeau ◽

Renee Tait ◽

...

Keyword(s):

Solid Solution ◽

Hydrogen Embrittlement ◽

Copper Content ◽

Vickers Microhardness ◽

Copper Alloys ◽

Alloy System ◽

Weight Percent ◽

Solid Solution Strengthening ◽

Solution Strengthening ◽

Palladium Copper Alloys

Strength, hardness, and ductility characteristics were determined for a series of palladium-copper alloys that compositionally vary from 5 to 25 weight percent copper. Alloy specimens subjected to vacuum annealing showed clear evidence of solid solution strengthening. These specimens showed, as a function of increasing copper content, increased yield strength, ultimate strength, and Vickers microhardness, while their ductility was little affected by compositional differences. Annealed alloy specimens subsequently subjected to exposure to hydrogen at 323 K and PH2 = 1 atm showed evidence of hydrogen embrittlement up to a composition of ~15 wt. % Cu. The magnitude of the hydrogen embrittlement decreased with increasing copper content in the alloy.

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PPARs as Metabolic Sensors and Therapeutic Targets in Liver Diseases

International Journal of Molecular Sciences ◽

10.3390/ijms22158298 ◽

2021 ◽

Vol 22 (15) ◽

pp. 8298

Author(s):

Hugo Christian Monroy-Ramirez ◽

Marina Galicia-Moreno ◽

Ana Sandoval-Rodriguez ◽

Alejandra Meza-Rios ◽

Arturo Santos ◽

...

Keyword(s):

Liver Diseases ◽

Metabolic Regulation ◽

Structural Changes ◽

Critical Role ◽

The Body ◽

Molecular Characteristics ◽

Signal Pathways ◽

Virus Infections ◽

Physiological Processes ◽

Hepatic Level

Carbohydrates and lipids are two components of the diet that provide the necessary energy to carry out various physiological processes to help maintain homeostasis in the body. However, when the metabolism of both biomolecules is altered, development of various liver diseases takes place; such as metabolic-associated fatty liver diseases (MAFLD), hepatitis B and C virus infections, alcoholic liver disease (ALD), and in more severe cases, hepatocelular carcinoma (HCC). On the other hand, PPARs are a family of ligand-dependent transcription factors with an important role in the regulation of metabolic processes to hepatic level as well as in other organs. After interaction with specific ligands, PPARs are translocated to the nucleus, undergoing structural changes to regulate gene transcription involved in lipid metabolism, adipogenesis, inflammation and metabolic homeostasis. This review aims to provide updated data about PPARs’ critical role in liver metabolic regulation, and their involvement triggering the genesis of several liver diseases. Information is provided about their molecular characteristics, cell signal pathways, and the main pharmacological therapies that modulate their function, currently engaged in the clinic scenario, or in pharmacological development.

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Atomic-resolution study on the interface structure and strain state reversion of the Bi2Sr2CuO6+δ/MgO heterostructure

Journal of Colloid and Interface Science ◽

10.1016/j.jcis.2021.02.063 ◽

2021 ◽

Author(s):

Jian Zhang ◽

Weizhen Wang ◽

Nan Wang ◽

Mingguang Wang ◽

Yang Qi

Keyword(s):

Strain State ◽

Interface Structure ◽

Atomic Resolution ◽

Resolution Study

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Proprotein Convertase 5/6 Is Critical for Embryo Implantation in Women: Regulating Receptivity by Cleaving EBP50, Modulating Ezrin Binding, and Membrane-Cytoskeletal Interactions

Endocrinology ◽

10.1210/en.2011-1273 ◽

2011 ◽

Vol 152 (12) ◽

pp. 5041-5052 ◽

Cited By ~ 22

Author(s):

Sophea Heng ◽

Ana Cervero ◽

Carlos Simon ◽

Andrew N. Stephens ◽

Ying Li ◽

...

Keyword(s):

Plasma Membrane ◽

Cellular Localization ◽

Structural Changes ◽

Current Knowledge ◽

Embryo Implantation ◽

Critical Role ◽

Human Endometrium ◽

Scaffolding Protein ◽

Proprotein Convertase ◽

Proteomic Approach

Establishment of endometrial receptivity is vital for successful embryo implantation; its failure causes infertility. Epithelial receptivity acquisition involves dramatic structural changes in the plasma membrane and cytoskeleton. Proprotein convertase 5/6 (PC6), a serine protease of the proprotein convertase (PC) family, is up-regulated in the human endometrium specifically at the time of epithelial receptivity and stromal cell decidualization. PC6 is the only PC member tightly regulated in this manner. The current study addressed the importance and mechanisms of PC6 action in regulating receptivity in women. PC6 was dysregulated in the endometrial epithelium during the window of implantation in infertile women of three demographically different cohorts. Its critical role in receptivity was evidenced by a significant reduction in mouse blastocyst attachment of endometrial epithelial cells after PC6 knockdown by small interfering RNA. Using a proteomic approach, we discovered that PC6 cleaved the key scaffolding protein, ezrin-radixin-moesin binding phosphoprotein 50 (EBP50), thereby profoundly affecting its interaction with binding protein ezrin (a key protein bridging actin filaments and plasma membrane), EBP50/ezrin cellular localization, and cytoskeleton-membrane connections. We further validated this novel PC6 regulation of receptivity in human endometrium in vivo in fertile vs. infertile patients. These results strongly indicate that PC6 plays a key role in regulating fundamental cellular remodeling processes, such as plasma membrane transformation and membrane-cytoskeletal interface reorganization. PC6 cleavage of a crucial scaffolding protein EBP50, thereby profoundly regulating membrane-cytoskeletal reorganization, greatly extends the current knowledge of PC biology and provides substantial new mechanistic insight into the fields of reproduction, basic cellular biology, and PC biochemistry.

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Atomic Resolution Study of Structural Rearrangements in Metal Clusters

Physics and Chemistry of Small Clusters ◽

10.1007/978-1-4757-0357-3_20 ◽

1987 ◽

pp. 127-132 ◽

Cited By ~ 8

Author(s):

Amanda K. Petford-Long ◽

N. J. Long ◽

David J. Smith ◽

L. R. Wallenberg ◽

J.-O. Bovin

Keyword(s):

Metal Clusters ◽

Atomic Resolution ◽

Structural Rearrangements ◽

Resolution Study

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Remodeling of cardiac fiber structure after infarction in rats quantified with diffusion tensor MRI

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00889.2002 ◽

2003 ◽

Vol 285 (3) ◽

pp. H946-H954 ◽

Cited By ~ 138

Author(s):

Junjie Chen ◽

Sheng-Kwei Song ◽

Wei Liu ◽

Mark McLean ◽

J. Stacy Allen ◽

...

Keyword(s):

Structural Changes ◽

Diffusion Tensor ◽

Critical Role ◽

Coronary Artery Occlusion ◽

Tissue Level ◽

Functional Adaptation ◽

Angular Deviation ◽

Diffusion Anisotropy ◽

Structural Remodeling ◽

Anisotropy Index

Structural remodeling of myocardium after infarction plays a critical role in functional adaptation. Diffusion tensor magnetic resonance imaging (DTMRI) provides a means for rapid and nondestructive characterization of the three-dimensional fiber architecture of cardiac tissues. In this study, microscopic structural changes caused by MI were evaluated in Fischer 344 rats 4 wk after infarct surgery. DTMRI studies were performed on 15 excised, formalin-fixed rat hearts of both infarct (left anterior descending coronary artery occlusion, n = 8) and control (sham, n = 7) rats. Infarct myocardium exhibited increased water diffusivity (41% increase in trace values) and decreased diffusion anisotropy (37% decrease in relative anisotropy index). The reduced diffusion anisotropy correlated negatively with microscopic fiber disarray determined by histological analysis ( R = 0.81). Transmural courses of fiber orientation angles in infarct zones were similar to those of normal myocardium. However, regional angular deviation of the diffusion tensor increased significantly in the infarct myocardium and correlated strongly with microscopic fiber disarray ( R = 0.86). These results suggest that DTMRI may provide a valuable tool for defining structural remodeling in diseased myocardium at the cellular and tissue level.

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Persistent Pulmonary Hypertension of the Newborn: Role of Nitric Oxide

Journal of Intensive Care Medicine ◽

10.1177/088506669501000602 ◽

1995 ◽

Vol 10 (6) ◽

pp. 270-282

Author(s):

Stella Kourembanas

Keyword(s):

Nitric Oxide ◽

Pulmonary Hypertension ◽

Structural Changes ◽

Critical Role ◽

Persistent Pulmonary Hypertension ◽

Cell Contractility ◽

Vasoactive Mediators ◽

Nitric Oxide Therapy

Persistent pulmonary hypertension of the newborn (PPHN) is a common cause of respiratory failure in the full-term neonate. Molecular and cellular studies in vascular biology have revealed that endothelial-derived mediators play a critical role in the pathogenesis and treatment of PPHN. Endothelial-derived vasoconstrictors, like endothelin, may increase smooth muscle cell contractility and growth, leading to the physiologic and structural changes observed in the pulmonary arterioles of infants with this disease. On the other hand, decreased production of the endothelial-derived relaxing factor, nitric oxide, may exacerbate pulmonary vasoreactivity and lead to more severe pulmonary hypertension. Exogenous (inhaled) nitric oxide therapy reduces pulmonary vascular resistance and improves oxygenation. The safety and efficacy of this therapy in reducing the need for extracorporeal membrane oxygenation and decreasing long-term morbidity is being tested in several trials nationally and abroad. Understanding the basic mechanisms that regulate the gene expression and production of these vasoactive mediators will lead to improved preventive and therapeutic strategies for PPHN.

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