scholarly journals Novel Experimentation for the Validation of Mechanistic Models to Describe Cold Dwell Sensitivity in Titanium Alloys

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1456
Author(s):  
Elizabeth E. Sackett ◽  
Martin R. Bache

Previous mechanistic models, proposed to explain the process of damage accumulation and stress redistribution between strong and weak regions inherent within the microstructure of α/β and near α titanium alloys, are validated through a matrix of experiments employing a non-standard variant of the alloy Ti 685. The grain size of the model material was deliberately processed to offer grains up to 20 mm in diameter, to facilitate constitutive measurements within individual grains. A range of experiments were performed under static and cyclic loading, with the fatigue cycle conducted under either strain or load control. Data will be reported to demonstrate significant variations in elastic and plastic properties between grains and emphasise the role of time dependent strain accumulation. Implications for the “dwell sensitive fatigue” or “cold creep” response of conventional titanium alloys will be discussed.

Author(s):  
Georgia Colleluori ◽  
Jessica Perugini ◽  
Giorgio Barbatelli ◽  
Saverio Cinti

AbstractThe mammary gland (MG) is an exocrine gland present in female mammals responsible for the production and secretion of milk during the process of lactation. It is mainly composed by epithelial cells and adipocytes. Among the features that make the MG unique there are 1) its highly plastic properties displayed during pregnancy, lactation and involution (all steps belonging to the lactation cycle) and 2) its requirement to grow in close association with adipocytes which are absolutely necessary to ensure MG’s proper development at puberty and remodeling during the lactation cycle. Although MG adipocytes play such a critical role for the gland development, most of the studies have focused on its epithelial component only, leaving the role of the neighboring adipocytes largely unexplored. In this review we aim to describe evidences regarding MG’s adipocytes role and properties in physiologic conditions (gland development and lactation cycle), obesity and breast cancer, emphasizing the existing gaps in the literature which deserve further investigation.


2019 ◽  
Vol 47 (1) ◽  
pp. 441-448 ◽  
Author(s):  
Christophe Caillat ◽  
Sourav Maity ◽  
Nolwenn Miguet ◽  
Wouter H. Roos ◽  
Winfried Weissenhorn

Abstract The endosomal sorting complex required for transport-III (ESCRT-III) and VPS4 catalyze a variety of membrane-remodeling processes in eukaryotes and archaea. Common to these processes is the dynamic recruitment of ESCRT-III proteins from the cytosol to the inner face of a membrane neck structure, their activation and filament formation inside or at the membrane neck and the subsequent or concomitant recruitment of the AAA-type ATPase VPS4. The dynamic assembly of ESCRT-III filaments and VPS4 on cellular membranes induces constriction of membrane necks with large diameters such as the cytokinetic midbody and necks with small diameters such as those of intraluminal vesicles or enveloped viruses. The two processes seem to use different sets of ESCRT-III filaments. Constriction is then thought to set the stage for membrane fission. Here, we review recent progress in understanding the structural transitions of ESCRT-III proteins required for filament formation, the functional role of VPS4 in dynamic ESCRT-III assembly and its active role in filament constriction. The recent data will be discussed in the context of different mechanistic models for inside-out membrane fission.


2019 ◽  
Vol 746 ◽  
pp. 394-405 ◽  
Author(s):  
Tea-Sung Jun ◽  
Xavier Maeder ◽  
Ayan Bhowmik ◽  
Gaylord Guillonneau ◽  
Johann Michler ◽  
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2008 ◽  
Vol 183 (2) ◽  
pp. 181-186 ◽  
Author(s):  
Alex Engel ◽  
Peter Walter

In the canonical model of membrane fusion, the integrity of the fusing membranes is never compromised, preserving the identity of fusing compartments. However, recent molecular simulations provided evidence for a pathway to fusion in which holes in the membrane evolve into a fusion pore. Additionally, two biological membrane fusion models—yeast cell mating and in vitro vacuole fusion—have shown that modifying the composition or altering the relative expression levels of membrane fusion complexes can result in membrane lysis. The convergence of these findings showing membrane integrity loss during biological membrane fusion suggests new mechanistic models for membrane fusion and the role of membrane fusion complexes.


2015 ◽  
Vol 227 ◽  
pp. 435-438 ◽  
Author(s):  
Joanna Loch ◽  
Alicja Łukaszczyk ◽  
Vincent Vignal ◽  
Halina Krawiec

The corrosion behaviour of titanium alloys is not well understood – especially the role of the microstructure and plastic strain. In this paper, the influence of the microstructure and plastic strain on the corrosion resistance of TiMo10Zr4 and Ti6Al4V alloys was studied in the Ringer’s solution at 37 °C. Measurements were performed for different pH values and in aerated and de-aerated solutions using potentiodynamic polarization techniques. Results obtained on the two alloys were compared. It was shown that in the absence of plastic strain TiMo10Zr4 shows better corrosion resistance than Ti6Al4V (especially for pH = 8). By contrast, the current density in the passive range measured after 8% plastic strain was greater on TiMo10Zr4 than on Ti6Al4V, indicating that the passive film on TiMo10Zr4 is less protective than that formed on Ti6Al4V.


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