scholarly journals Metal Release from a Biomedical CoCrMo Alloy in Mixed Protein Solutions Under Static and Sliding Conditions: Effects of Protein Aggregation and Metal Precipitation

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Zheng Wei ◽  
Valentin Romanovski ◽  
Luimar Filho ◽  
Cecilia Persson ◽  
Yolanda Susanne Hedberg
Author(s):  
Dejuan Kong ◽  
Anita Penkova ◽  
Satwindar Singh Sadhal

Protein aggregation rate is known to be influenced by shear flow in protein solutions. This has important physiological implications as many of the body functions involve shear flow. Fluid mechanical shear can affect interactions between protein molecules, initiate protein aggregation, and further affect their biological activity. The shear rate is therefore an important parameter either to determine or to influence the properties of the protein solution when it forms a nucleus or aggregates. For experiments, the number density of nuclei can be controlled by using an optimal shear rate and protein concentration. However, this requires theoretical information on the shear rate for the experimental conditions. With this motivation, we have designed an experiment in which we can effectively apply shear with flow characteristics that can be calculated. Specifically, in a small hemispherically-shaped bowl, 4 mm in diameter we place the protein solution and insert a rounded rod that can be vibrated rotationally or laterally, maintaining spherical symmetry in the liquid region. This system is particularly useful when only small quantities of expensive protein solutions can be used for experimentation. We have carried out the mathematical analysis of the time-dependent flow field between two concentric hemispheres by the perturbation method using ε = U0/ωa ≪ 1 as a small parameter where U0 is a characteristic velocity, ω is the oscillation frequency and a is a length scale based on the vessel dimensions (bowl radius). We have obtained an analytical solution for the velocity field, and the shear rate in the liquid. In addition, with the nonlinear interaction of the oscillatory flow, there is a nonzero time-independent mean flow (known as streaming). With the integrated effect of shear in the liquid region, this result will be useful for conducting aggregation experiment in which the effective shear rate can be correlated to the aggregation rate.


2009 ◽  
Vol 19 (19) ◽  
pp. 3046-3055 ◽  
Author(s):  
Manish Dubey ◽  
Kazunori Emoto ◽  
Hironobu Takahashi ◽  
David G. Castner ◽  
David W. Grainger

2012 ◽  
Vol 84 (13) ◽  
pp. 5759-5764 ◽  
Author(s):  
Arumugam Sivanesan ◽  
Govindasamy Kalaivani ◽  
Anna Fischer ◽  
Konstanze Stiba ◽  
Silke Leimkühler ◽  
...  

CORROSION ◽  
10.5006/2504 ◽  
2017 ◽  
Vol 73 (12) ◽  
pp. 1423-1436 ◽  
Author(s):  
Y. Hedberg ◽  
M.-E. Karlsson ◽  
Z. Wei ◽  
M. Žnidaršič ◽  
I. Odnevall Wallinder ◽  
...  

Author(s):  
James R. Gaylor ◽  
Fredda Schafer ◽  
Robert E. Nordquist

Several theories on the origin of the melanosome exist. These include the Golgi origin theory, in which a tyrosinase-rich protein is "packaged" by the Golgi apparatus, thus forming the early form of the melanosome. A second theory postulates a mitochondrial origin of melanosomes. Its author contends that the melanosome is a modified mitochondria which acquires melanin during its development. A third theory states that a pre-melanosome is formed in the smooth or rough endoplasmic reticulum. Protein aggregation is suggested by one author as a possible source of the melanosome. This fourth theory postulates that the melanosome originates when the protein products of several genetic loci aggregate in the cytoplasm of the melanocyte. It is this protein matrix on which the melanin is deposited. It was with these theories in mind that this project was undertaken.


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