Oscillatory Flow Between Two Hemispheres for Shearing Protein Solution

2015 ◽  
Vol 137 (10) ◽  
Author(s):  
Dejuan Kong ◽  
Anita Penkova ◽  
Satwindar Singh Sadhal
Keyword(s):  
Shear Rate ◽  
Oscillatory Flow ◽  
Molecular Mechanisms ◽  
Outer Boundary ◽  
Experimental System ◽  
Theoretical Background ◽  
Physical Factors ◽  
Protein Solution ◽  
Steady Streaming ◽  
And Control

Protein aggregation, one of the common molecular mechanisms for neurodegenerative diseases, is affected by variety of physical factors, one of which is shear rate of protein solution. This paper provides theoretical background on the shear rate in the experimental system we have proposed to effectively apply and control shear. We carried out the mathematical analysis of the flow field resulted from torsional or transverse oscillation on the outer boundary between two concentric hemispheres by perturbation method. We have obtained analytical solutions for the velocity field, the shear rate, and the flow pattern of steady streaming created by the nonlinear interaction of the oscillatory flow.

Oscillatory Flow Between Two Hemispheres for Shearing Protein Solution

2013 ◽  
Author(s):  
Dejuan Kong ◽  
Anita Penkova ◽  
Satwindar Singh Sadhal
Keyword(s):  
Shear Rate ◽  
Shear Flow ◽  
Protein Aggregation ◽  
Oscillatory Flow ◽  
The Body ◽  
Protein Solutions ◽  
Liquid Region ◽  
Mean Flow ◽  
Protein Solution ◽  
Aggregation Rate

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.

Oscillatory flow over a cylinder resting on a plane boundary

1996 ◽  
Vol 7 (6) ◽  
pp. 545-558 ◽  
Author(s):  
M. F. Wybrow ◽  
N. Riley
Keyword(s):  
Circular Cylinder ◽  
Boundary Layers ◽  
Outer Layer ◽  
Oscillatory Flow ◽  
Outer Boundary ◽  
Reynolds Numbers ◽  
Plane Boundary ◽  
Simple Experiment ◽  
Steady Streaming ◽  
Streaming Motion

Oscillatory flow over a circular cylinder, or part-cylinder, placed on a plane boundary, when the Strouhal and streaming Reynolds numbers are large, is considered. The solution is developed in matching inner and outer boundary layers. A steady streaming motion in the outer layer can lead to a net flow away from the cylinder along the plane boundary. A simple experiment substantiates this prediction, and the implications for bed-scouring are examined.

Relationship Between Gamma-glutamyl Transpeptidase Activity and Inflammatory Response in Lichen Planus

2018 ◽  
Vol 69 (3) ◽  
pp. 739-743 ◽  
Author(s):  
Madalina Irina Mitran ◽  
Ilinca Nicolae ◽  
Corina Daniela Ene ◽  
Cristina Iulia Mitran ◽  
Clara Matei ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Lichen Planus ◽  
Inflammatory Process ◽  
Molecular Mechanisms ◽  
Functional Adaptation ◽  
Physical Factors ◽  
Inflammatory Disorder ◽  
Gamma Glutamyl Transpeptidase ◽  
Gamma Glutamyl ◽  
Glutamyl Transpeptidase

Chemicals used in the manufacture of synthetic fibers have been associated with undesirable side effects such as itching or skin lesions and it seems that they are involved in the induction of pathological processes such as oxidative stress and inflammation. Lichen planus (LP) can be regarded as an inflammatory disorder, chemical and physical factors playing an important role in the perpetuation of the inflammatory process. Gamma-glutamyl transpeptidase (GGT) plays an important role in the preservation of skin architecture and modulation of skin inflammation. In this study, we found that GGT activity is increased in LP patients with mild inflammation, whilst GGT is inactivated under conditions of severe inflammation. Therefore, GGT is involved in the inflammatory process, but there is no a positive correlation between its activity and the intensity of the inflammatory response. This functional adaptation of the enzyme may be due to down-regulation of its synthesis under free radical overload conditions. Understanding the molecular mechanisms involved in the modulation of intracellular redox homeostasis is an important step in the pharmacological management of patients with LP.

The Protective Effects of Green Tea Catechins in the Management of Neurodegenerative Diseases: A Review

2019 ◽  
Vol 16 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Tahereh Farkhondeh ◽  
Hanieh Shaterzadeh Yazdi ◽  
Saeed Samarghandian
Keyword(s):  
Neurodegenerative Diseases ◽  
Signaling Pathways ◽  
Green Tea ◽  
Molecular Mechanisms ◽  
Main Role ◽  
Related Factor ◽  
Protective Effects ◽  
Tea Catechins ◽  
Green Tea Catechins ◽  
And Control

Background: The therapeutic strategies to manage neurodegenerative diseases remain limited and it is necessary to discover new agents for their prevention and control. Oxidative stress and inflammation play a main role in the pathogenesis of neurodegenerative diseases. The aim of this study is to review the effects of green tea catechins against the Neurodegenerative Diseases. Methods: In this study, we extensively reviewed all articles on the terms of Green tea, catechins, CNS disorders, and different diseases in PubMed, Science Direct, Scopus, and Google Scholar databases between the years 1990 and 2017. Results: The present study found that catechins, the major flavonoids in green tea, are powerful antioxidants and radical scavengers which possess the potential roles in the management of neurodegenerative diseases. Catechins modulate the cellular and molecular mechanisms through the inflammation-related NF-&amp;#954;B and the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathways. Conclusion: The findings of the present review shows catechins could be effective against neurodegenerative diseases due to their antioxidation and anti-inflammation effects and the involved biochemical pathways including Nrf2 and NF-kB signaling pathways.<P&gt;

scholarly journals Proanthocyanidins against Oxidative Stress: From Molecular Mechanisms to Clinical Applications

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Lingyu Yang ◽  
Dehai Xian ◽  
Xia Xiong ◽  
Rui Lai ◽  
Jing Song ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Signaling Pathways ◽  
Molecular Mechanisms ◽  
Metabolic Diseases ◽  
Low Cost ◽  
Natural Agents ◽  
Molecular Damage ◽  
And Control

Proanthocyanidins (PCs) are naturally occurring polyphenolic compounds abundant in many vegetables, plant skins (rind/bark), seeds, flowers, fruits, and nuts. Numerousin vitroandin vivostudies have demonstrated myriad effects potentially beneficial to human health, such as antioxidation, anti-inflammation, immunomodulation, DNA repair, and antitumor activity. Accumulation of prooxidants such as reactive oxygen species (ROS) exceeding cellular antioxidant capacity results in oxidative stress (OS), which can damage macromolecules (DNA, lipids, and proteins), organelles (membranes and mitochondria), and whole tissues. OS is implicated in the pathogenesis and exacerbation of many cardiovascular, neurodegenerative, dermatological, and metabolic diseases, both through direct molecular damage and secondary activation of stress-associated signaling pathways. PCs are promising natural agents to safely prevent acute damage and control chronic diseases at relatively low cost. In this review, we summarize the molecules and signaling pathways involved in OS and the corresponding therapeutic mechanisms of PCs.

Asymptotic Behavior in Slumping From a Cylindrical Tank

1984 ◽  
Vol 106 (3) ◽  
pp. 279-284 ◽  
Author(s):  
Y. Bai ◽  
W. Johnson ◽  
R. G. M. Low ◽  
S. K. Ghosh
Keyword(s):  
Transition Period ◽  
Health And Safety ◽  
Local Environment ◽  
Theoretical Background ◽  
Hazardous Substance ◽  
Substance Flows ◽  
Linear Relationships ◽  
Characteristic Features ◽  
And Control ◽  
Future Work

When an oil tank collapses or ruptures any contained hazardous substance flows outwards and can damage nearby plant or people as well as lead to pollution of the local environment. In recent years, this and similar subjects have given rise to a new kind of engineering—spill prevention and control. However, theoretical background, backed by experiment, is lacking to work out reliable regulations. An intermediate-asymptotic analysis for late-stage spreading is carried out in this paper. This analysis reveals several characteristic features of the spill wave such as transition period and linear relationships between spreading area and time, and wave front velocity and the inverse of zone radius. Most of the latter results have been verified by model experiment. This paper also discusses the discrepancies between observations and the theory suggested in a recent UK Health and Safety Executive report. Finally, the present paper puts forward proper modeling rules for future work.

scholarly journals MicroRNAs in Autoimmunity and Hematological Malignancies

2018 ◽  
Vol 19 (10) ◽  
pp. 3139 ◽  
Author(s):  
Mirco Marco ◽  
Alice Ramassone ◽  
Sara Pagotto ◽  
Eleni Anastasiadou ◽  
Angelo Veronese ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Hematological Malignancies ◽  
Immune Cell ◽  
Immunological Tolerance ◽  
Considerable Effort ◽  
Control Networks ◽  
Immune Cell Subsets ◽  
Bidirectional Relationship ◽  
Relevant Role ◽  
And Control

Autoimmunity and hematological malignancies are often concomitant in patients. A causal bidirectional relationship exists between them. Loss of immunological tolerance with inappropriate activation of the immune system, likely due to environmental and genetic factors, can represent a breeding ground for the appearance of cancer cells and, on the other hand, blood cancers are characterized by imbalanced immune cell subsets that could support the development of the autoimmune clone. Considerable effort has been made for understanding the proteins that have a relevant role in both processes; however, literature advances demonstrate that microRNAs (miRNAs) surface as the epigenetic regulators of those proteins and control networks linked to both autoimmunity and hematological malignancies. Here we review the most up-to-date findings regarding the miRNA-based molecular mechanisms that underpin autoimmunity and hematological malignancies.

scholarly journals Enhancement of Dopaminergic Differentiation in Proliferating Midbrain Neuroblasts by Sonic Hedgehog and Ascorbic Acid

2004 ◽  
Vol 11 (1-2) ◽  
pp. 45-57 ◽  
Author(s):  
Floriana Volpicelli ◽  
Claudia Consales ◽  
Massimiliano Caiazzo ◽  
Luca Colucci-D'Amato ◽  
Carla Perrone-Capano ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Sonic Hedgehog ◽  
Molecular Mechanisms ◽  
Experimental System ◽  
Serum Free Medium ◽  
Free Medium ◽  
Ventral Mesencephalon ◽  
Mes Cells ◽  
Dopaminergic Differentiation

We analyzed the molecular mechanisms involved in the acquisition and maturation of dopaminergic (DA) neurons generated in vitro from rat ventral mesencephalon (MES) cells in the presence of mitogens or specific signaling molecules. The addition of basic fibroblast growth factor (bFGF) to MES cells in serum-free medium stimulates the proliferation of neuroblasts but delays DA differentiation. Recombinant Sonic hedgehog (SHH) protein increases up to three fold the number of tyrosine hydroxylase (TH)-positive cells and their differentiation, an effect abolished by anti-SHH antibodies. The expanded cultures are rich in nestin-positive neurons, glial cells are rare, allTH+neurons are DA, and all DA and GABAergic markers analyzed are expressed. Adding ascorbic acid to bFGF/SHH-treated cultures resulted in a further five- to seven-fold enhancement of viable DA neurons. This experimental system also provides a powerful tool to generate DA neurons from single embryos. Our strategy provides an enriched source of MES DA neurons that are useful for analyzing molecular mechanisms controlling their function and for experimental regenerative approaches in DA dysfunction.

scholarly journals Development of integrated multi-trophic aquaculture (IMTA) for tropical brackishwater species in Sindhudurg District, Maharashtra, west coast of India

2018 ◽  
Vol 65 (1) ◽  
Author(s):  
C. P. Balasubramanian ◽  
Shailesh S. Mhaskar ◽  
Krishna Sukumaran ◽  
A. Panigrahi ◽  
Kurmaraguru Vasagam ◽  
...  
Keyword(s):  
Experimental System ◽  
Open Water ◽  
Trophic Levels ◽  
Cost Ratio ◽  
Benefit Cost Ratio ◽  
System A ◽  
Etroplus Suratensis ◽  
Penaeus Indicus ◽  
Benefit Cost ◽  
And Control

Integrated multi-trophic aquaculture (IMTA), farming of species from different trophic levels and with complimentary ecosystem function, is regarded as a suitable approach to develop a sustainable aquaculture system. In order to establish an IMTA system, a study was carried out in Sindhudurg District, Maharashtra, India for selected tropical brackish-water species. Two equal sized pens (250 m2) were constructed for IMTA and control respectively in each land based system and open water cages were set in the estuary. Different combinations of fed species (Chanos chanos, Etroplus suratensis, Mugil cephalus, Penaeus indicus) and an extractive crop (Crassostrea madrasensis) were stocked in IMTA experimental system whereas monoculture of P. indicus served as control. Water quality characteristics were found to be within the admissible limits. Soil organic carbon was found to be lesser in the IMTA system compared to control. The productivity of IMTA system was higher than control: 3250 kg h-1 vs 2000 kg ha-1. Further, income and benefit-cost ratio was found to be higher in IMTA pens. The present study concludes that IMTA is a possible option for system diversification as well as species diversification without compromising economic profitability of culture.

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