scholarly journals Glycosaminoglycan-Inspired Biomaterials for the Development of Bioactive Hydrogel Networks

Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 978 ◽  
Author(s):  
Mariana I. Neves ◽  
Marco Araújo ◽  
Lorenzo Moroni ◽  
Ricardo M.P. da Silva ◽  
Cristina C. Barrias
Keyword(s):  
Mechanical Properties ◽  
Extracellular Matrix ◽  
Biological Activity ◽  
Growth Factors ◽  
Mechanical Stability ◽  
Biological Molecules ◽  
Inhibiting Factors ◽  
Wide Range ◽  
Different Sources

Glycosaminoglycans (GAG) are long, linear polysaccharides that display a wide range of relevant biological roles. Particularly, in the extracellular matrix (ECM) GAG specifically interact with other biological molecules, such as growth factors, protecting them from proteolysis or inhibiting factors. Additionally, ECM GAG are partially responsible for the mechanical stability of tissues due to their capacity to retain high amounts of water, enabling hydration of the ECM and rendering it resistant to compressive forces. In this review, the use of GAG for developing hydrogel networks with improved biological activity and/or mechanical properties is discussed. Greater focus is given to strategies involving the production of hydrogels that are composed of GAG alone or in combination with other materials. Additionally, approaches used to introduce GAG-inspired features in biomaterials of different sources will also be presented.

scholarly journals The assembly of integrin adhesion complexes requires both extracellular matrix and intracellular rho/rac GTPases.

1995 ◽  
Vol 131 (6) ◽  
pp. 1857-1865 ◽  
Author(s):  
N A Hotchin ◽  
A Hall
Keyword(s):  
Extracellular Matrix ◽  
Growth Factors ◽  
Complex Formation ◽  
Map Kinase ◽  
Human Fibroblasts ◽  
Focal Adhesions ◽  
Small Gtpases ◽  
Wide Range ◽  
Focal Complex ◽  
Rho Family

Interaction of cells with extracellular matrix via integrin adhesion receptors plays an important role in a wide range of cellular: functions, for example cell growth, movement, and differentiation. Upon interaction with substrate, integrins cluster and associate with a variety of cytoplasmic proteins to form focal complexes and with the actin cytoskeleton. Although the intracellular signals induced by integrins are at present undefined, it is thought that they are mediated by proteins recruited to the focal complexes. It has been suggested, for example, that after recruitment to focal adhesions p125FAK can activate the ERK1/2 MAP kinase cascade. We have previously reported that members of the rho family of small GTPases can trigger the assembly of focal complexes when activated in cells. Using microinjection techniques, we have now examined the role of the extracellular matrix and of the two GTP-binding proteins, rac and rho, in the assembly of integrin complexes in both mouse and human fibroblasts. We find that the interaction of integrins with extracellular matrix alone is not sufficient to induce integrin clustering and focal complex formation. Similarly, activation of rho or rac by extracellular growth factors does not lead to focal complex formation in the absence of matrix. Focal complexes are only assembled in the presence of both matrix and functionally active members of the rho family. In agreement with this, the interaction of integrins with matrix in the absence of rho/rac activity is unable to activate the ERK1/2 kinases in Swiss 3T3 cells. In fact, ERK1/2 can be activated fully by growth factors in the absence of matrix and it seems unlikely, therefore, that the adhesion dependence of fibroblast growth is mediated through the ras/MAP kinase pathway. We conclude that extracellular matrix is not sufficient to trigger focal complex assembly and subsequent integrin-dependent signal transduction in the absence of functionally active members of the rho family of GTPases.

Extracellular matrix in obesity – cancer interactions

2015 ◽  
Vol 22 (2) ◽  
Author(s):  
Stephany C. Barreto ◽  
Christina A. Hopkins ◽  
Meghnad Bhowmick ◽  
Amitabha Ray
Keyword(s):  
Extracellular Matrix ◽  
Growth Factors ◽  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Matricellular Proteins ◽  
Wide Range ◽  
Range Of Functions ◽  
Almost All ◽  
Chemical Mediators

AbstractObesity or overweight is a risk factor for several health disorders such as type 2 diabetes, hypertension, and certain cancers. Furthermore, obesity affects almost all body systems including the extracellular matrix (ECM) by generating a pro-inflammatory environment, which are associated with abnormal secretions of several cytokines or hormonal substances, for example, insulin-like growth factors (IGFs), leptin, and sex hormones. These chemical mediators most likely have a great impact on the ECM. Accumulating evidence suggests that both obesity and ECM can influence tumor growth and progression through a number of chemical mediators. Conversely, cells in the connective tissue, namely fibroblasts and macrophages, support and aggravate the inflammatory situation in obesity by releasing several cytokines or growth factors such as vascular endothelial growth factor, epidermal growth factor, and transforming growth factor-beta (TGF-β). A wide range of functions are performed by TGF-β in normal health and pathological conditions including tumorigenesis. Breast cancer in postmenopausal women is a classic example of obesity-related cancer wherein several of these conditions, for example, higher levels of pro-inflammatory cytokines, impairment in the regulation of estrogen and growth factors, and dysregulation of different ECM components may favor the neoplastic process. Aberrant expressions of ECM components such as matrix metalloproteinases or matricellular proteins in both obesity and cancer have been reported by many studies. Nonstructural matricellular proteins, viz., thrombospondins, secreted protein acidic and rich in cysteine (SPARC), and Cyr61-CTGF-Nov (CCN), which function as modulators of cell-ECM interactions, exhibit protean behavior in cancer. Precise understanding of ECM biology can provide potential therapeutic targets to combat obesity-related pathologies.

scholarly journals Diversity of Adult Neural Stem and Progenitor Cells in Physiology and Disease

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 2045
Author(s):  
Zachary Finkel ◽  
Fatima Esteban ◽  
Brianna Rodriguez ◽  
Tianyue Fu ◽  
Xin Ai ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Spinal Cord ◽  
Extracellular Matrix ◽  
Cerebrospinal Fluid ◽  
Growth Factors ◽  
Energy Metabolism ◽  
Progenitor Cells ◽  
Ependymal Cells ◽  
Stem And Progenitor Cells ◽  
The Brain

Adult neural stem and progenitor cells (NSPCs) contribute to learning, memory, maintenance of homeostasis, energy metabolism and many other essential processes. They are highly heterogeneous populations that require input from a regionally distinct microenvironment including a mix of neurons, oligodendrocytes, astrocytes, ependymal cells, NG2+ glia, vasculature, cerebrospinal fluid (CSF), and others. The diversity of NSPCs is present in all three major parts of the CNS, i.e., the brain, spinal cord, and retina. Intrinsic and extrinsic signals, e.g., neurotrophic and growth factors, master transcription factors, and mechanical properties of the extracellular matrix (ECM), collectively regulate activities and characteristics of NSPCs: quiescence/survival, proliferation, migration, differentiation, and integration. This review discusses the heterogeneous NSPC populations in the normal physiology and highlights their potentials and roles in injured/diseased states for regenerative medicine.

Individual construction of freeform-fabricated polycaprolactone scaffolds for osteogenesis

2017 ◽  
Vol 62 (5) ◽  
Author(s):  
Lu Liu ◽  
Guixin Shi ◽  
Ying Cui ◽  
Hui Li ◽  
Zhengchao Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Extracellular Matrix ◽  
Biological Activity ◽  
Individual Differences ◽  
Disease Status ◽  
High Porosity ◽  
Mechanical Parameters ◽  
Freeform Fabrication ◽  
Natural Bone ◽  
Rabbit Femur

AbstractThe construction of engineered bone mostly focuses on simulating the extracellular matrix (ECM) for proper biological activity. However, the complexity of architecture and the variability of the mechanical properties of natural bones are related to individual differences in age, nutritional state, mechanical loading and disease status. Defect substitutions should be normed with the host natural bone, balancing architectural and mechanical adaption, as well as biological activity. Using a freeform fabrication (FFF) method, we prepared polycaprolactone (PCL) scaffolds with different architectures. With simulation of structural and mechanical parameters of rabbit femur cancellous bone, individual defect substitution with the characteristics of the rabbit femur was obtained with high porosity and connectivity. Biological adaption

scholarly journals Diversity of Adult Neural Stem and Progenitor Cells in Physiology and Disease

2021 ◽  
Author(s):  
Zachary Finkel ◽  
FATIMA ESTEBAN ◽  
Brianna Rodriguez ◽  
TIANYUE FU ◽  
Xin Ai ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Spinal Cord ◽  
Extracellular Matrix ◽  
Cerebrospinal Fluid ◽  
Growth Factors ◽  
Energy Metabolism ◽  
Progenitor Cells ◽  
Ependymal Cells ◽  
Stem And Progenitor Cells ◽  
The Brain

Adult neural stem and progenitor cells (NSPCs) contribute to learning, memory, maintenance of homeostasis, energy metabolism and many other essential processes. They are highly heterogeneous populations that require input from a regionally distinct microenvironment including a mix of neurons, oligodendrocytes, astrocytes, ependymal cells, NG2+ glia, vasculature, cerebrospinal fluid (CSF), and others. The diversity of NSPCs is present in all three major parts of the CNS, i.e., the brain, spinal cord, and retina. Intrinsic and extrinsic signals, e.g., neurotrophic and growth factors, master transcription factors, and mechanical properties of the extracellular matrix (ECM), collectively regulate activities and characteristics of NSPCs: quiescence/survival, proliferation, migration, differentiation, and integration. This review discusses the heterogeneous NSPC populations in the normal physiology and highlights their potentials and roles in injured/diseased states for regenerative medicine.

Biocomposites from the reinforcement of a tung oil-based thermosetting resin with collagen

2017 ◽  
Vol 1 (9) ◽  
pp. 1795-1803 ◽  
Author(s):  
Audrey Scholz ◽  
Russell L. Lewis ◽  
Michael A. Bachan ◽  
Amanda L. Stewart ◽  
Rafael L. Quirino
Keyword(s):  
Mechanical Properties ◽  
Biological Molecules ◽  
Thermosetting Resin ◽  
Tung Oil ◽  
Biomedical Field ◽  
Different Sources

Collagen from three different sources has been added to a tung oil-based thermosetting resin in order to enhance its mechanical properties for possible applications in the biomedical field as materials directly derived from biological molecules.

Mechanical Properties and Dislocation Structure of Single Crystal Cdte Deformed in Compression at 300°C

1976 ◽  
Vol 34 ◽  
pp. 592-593
Author(s):  
Ernest L. Hall ◽  
J. B. Vander Sande
Keyword(s):  
Mechanical Properties ◽  
Single Crystal ◽  
Dislocation Structure ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Optical Devices ◽  
Semiconductor Compound ◽  
Wide Range ◽  
Sample Orientation

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.

Intimate Partner Violence and Help-Seeking

2017 ◽  
Vol 22 (4) ◽  
pp. 263-281 ◽  
Author(s):  
Solveig Lelaurain ◽  
Pierluigi Graziani ◽  
Grégory Lo Monaco
Keyword(s):  
Social Psychology ◽  
Intimate Partner Violence ◽  
Partner Violence ◽  
Help Seeking ◽  
Intimate Partner ◽  
Review Of The Literature ◽  
Social Concern ◽  
Inclusion Criteria ◽  
Inhibiting Factors ◽  
Wide Range

Abstract. Intimate partner violence (IPV) is a global social concern: many women are affected by this phenomenon and by the difficulty of putting an end to it. This review of the literature aims to identify help-seeking facilitating and inhibiting factors in response to IPV. It was carried out on the PsycINFO and Medline databases using the following keywords: “intimate partner violence,” “domestic violence,” “help-seeking,” and “help-seeking barrier.” Ninety out of 771 eligible publications were included on the basis of inclusion criteria. The results highlight that (1) research on this phenomenon is very recent and underdeveloped in Europe, (2) theoretical and conceptual frameworks are poorly developed and extended, (3) there is a significant impact of violence characteristics (e.g., severity, type) on help-seeking, and (4) help-seeking is a complex and multifactorial process influenced by a wide range of factors simultaneously individual and social. To conclude, these findings lead us to propose a psychosocial conceptualization of the help-seeking process by indicating how the levels of explanation approach in social psychology can be applied to this field of research in order to increase our understanding of this phenomenon.

An analysis of the transport properties and mechanical stability of rapidly solidified Al-Sb alloy

2015 ◽  
Vol 10 (2) ◽  
pp. 2663-2681
Author(s):  
Rizk El- Sayed ◽  
Mustafa Kamal ◽  
Abu-Bakr El-Bediwi ◽  
Qutaiba Rasheed Solaiman
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Melt Spinning ◽  
Elastic Moduli ◽  
Mechanical Stability ◽  
Microstructural Analysis ◽  
Alloy System ◽  
Antimony Content ◽  
The Stability ◽  
Rapidly Solidified

The structure of a series of AlSb alloys prepared by melt spinning have been studied in the as melt–spun ribbons  as a function of antimony content .The stability  of these structures has  been  related to that of the transport and mechanical properties of the alloy ribbons. Microstructural analysis was performed and it was found that only Al and AlSb phases formed for different composition.  The electrical, thermal and the stability of the mechanical properties are related indirectly through the influence of the antimony content. The results are interpreted in terms of the phase change occurring to alloy system. Electrical resistivity, thermal conductivity, elastic moduli and the values of microhardness are found to be more sensitive than the internal friction to the phase changes. 

Structure and properties of compact articles from high-alloyed iron powder with adding of boron nitride

2020 ◽  
pp. 39-48
Author(s):  
B. O. Bolshakov ◽  
◽  
R. F. Galiakbarov ◽  
A. M. Smyslov ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Grain Boundary ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Operating Conditions ◽  
Structure And Properties ◽  
Steam Turbines ◽  
Friction Forces ◽  
Wide Range

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.

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