scholarly journals Surface Modifications of Biodegradable Metallic Foams for Medical Applications

Coatings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 819
Author(s):  
Renáta Oriňaková ◽  
Radka Gorejová ◽  
Zuzana Orságová Králová ◽  
Andrej Oriňak
Keyword(s):  
Bone Tissue ◽  
Surface Modifications ◽  
Metallic Foam ◽  
Future Research ◽  
Medical Applications ◽  
Metallic Foams ◽  
Preparation Methods ◽  
Processing Technologies ◽  
Metallic Biomaterials ◽  
Bonding Properties

Significant progress was achieved presently in the development of metallic foam-like materials improved by biocompatible coatings. Material properties of the iron, magnesium, zinc, and their alloys are promising for their uses in medical applications, especially for orthopedic and bone tissue purposes. Current processing technologies and a variety of modifications of the surface and composition facilitate the design of adjusted medical devices with desirable mechanical, morphological, and functional properties. This article reviews the recent progress in the design of advanced degradable metallic biomaterials perfected by different coatings: polymer, inorganic ceramic, and metallic. Appropriate coating of metallic foams could improve the biocompatibility, osteogenesis, and bone tissue-bonding properties. In this paper, a comprehensive review of different coating types used for the enhancement of one or several properties of biodegradable porous implants is given. An outline of the conventional preparation methods of metallic foams and a brief overview of different alloys for medical applications are also provided. In addition, current challenges and future research directions of processing and surface modifications of biodegradable metallic foams for medical applications are suggested.

scholarly journals Influencing Factors on the Physicochemical Characteristics of Tea Polysaccharides

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3457
Author(s):  
Ting Hu ◽  
Peng Wu ◽  
Jianfeng Zhan ◽  
Weixin Wang ◽  
Junfeng Shen ◽  
...  
Keyword(s):  
Influencing Factors ◽  
Biological Activities ◽  
Structural Difference ◽  
Physicochemical Characteristics ◽  
Bioactive Constituents ◽  
Preparation Methods ◽  
Processing Technologies ◽  
Chemical Structures ◽  
Tea Polysaccharides ◽  
Fine Structures

Tea polysaccharides (TPSs) are one of the main bioactive constituents of tea with various biological activities such as hypoglycemic effect, antioxidant, antitumor, and immunomodulatory. The bioactivities of TPSs are directly associated with their structures such as chemical composition, molecular weight, glycosidic linkages, and conformation among others. To study the relationship between the structures of TPSs and their bioactivities, it is essential to elucidate the structure of TPSs, particularly the fine structures. Due to the vast variation nature of monosaccharide units and their connections, the structure of TPSs is extremely complex, which is also affected by several major factors including tea species, processing technologies of tea and isolation methods of TPSs. As a result of the complexity, there are few studies on their fine structures and chain conformation. In the present review, we aim to provide a detailed summary of the multiple factors influencing the characteristics of TPS chemical structures such as variations of tea species, degree of fermentation, and preparation methods among others as well as their applications. The main aspects of understanding the structural difference of TPSs and influencing factors are to assist the study of the structure and bioactivity relationship and ultimately, to control the production of the targeted TPSs with the most desired biological activity.

scholarly journals A Bibliometric Analysis of the Global Trend of Using Alginate, Gelatine, and Hydroxyapatite for Bone Tissue Regeneration Applications

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 647
Author(s):  
Mohamed Saiful Firdaus Hussin ◽  
Aludin Mohd Serah ◽  
Khairul Azri Azlan ◽  
Hasan Zuhudi Abdullah ◽  
Maizlinda Izwana Idris ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Bibliometric Analysis ◽  
Research Work ◽  
The United States ◽  
Research Area ◽  
Bone Tissue Regeneration ◽  
Future Research ◽  
Starting Point

Collecting information from previous investigations and expressing it in a scientometrics study can be a priceless guide to getting a complete overview of a specific research area. The aim of this study is to explore the interrelated connection between alginate, gelatine, and hydroxyapatite within the scope of bone tissue and scaffold. A review of traditional literature with data mining procedures using bibliometric analyses was considered to identify the evolution of the selected research area between 2009 and 2019. Bibliometric methods and knowledge visualization technologies were implemented to investigate diverse publications based on the following indicators: year of publication, document type, language, country, institution, author, journal, keyword, and number of citations. An analysis using a bibliometric study found that 7446 papers were located with the keywords “bone tissue” and “scaffold”, and 1767 (alginate), 185 (gelatine), 5658 (hydroxyapatite) papers with those specific sub keywords. The number of publications that relate to “tissue engineering” and bone more than doubled between 2009 (1352) and 2019 (2839). China, the United States and India are the most productive countries, while Sichuan University and the Chinese Academy of Science from China are the most important institutions related to bone tissue scaffold. Materials Science and Engineering C is the most productive journal, followed by the Journal of Biomedical Materials Research Part A. This paper is a starting point, providing the first bibliometric analysis study of bone tissue and scaffold considering alginate, gelatine and hydroxyapatite. A bibliometric analysis would greatly assist in giving a scientific insight to support desired future research work, not only associated with bone tissue engineering applications. It is expected that the analysis of alginate, gelatine and hydroxyapatite in terms of 3D bioprinting, clinical outcomes, scaffold architecture, and the regenerative medicine approach will enhance the research into bone tissue engineering in the near future. Continued studies into these research fields are highly recommended.

scholarly journals A critical review on the development and performance of polymer/graphene nanocomposites

2018 ◽  
Vol 25 (6) ◽  
pp. 1059-1073 ◽  
Author(s):  
Weifeng Chen ◽  
Hu Weimin ◽  
Dejiang Li ◽  
Shaona Chen ◽  
Zhongxu Dai
Keyword(s):  
Polymer Nanocomposites ◽  
Electronic Conductivity ◽  
Future Research ◽  
Preparation Methods ◽  
Graphene Nanocomposites ◽  
Advantages And Disadvantages ◽  
Solution Blending ◽  
Potential Applications ◽  
New Type ◽  
And Performance

AbstractGraphene (graphene) is a new type of two-dimensional inorganic nanomaterial developed in recent years. It can be used as an ideal inorganic nanofiller for the preparation of polymer nanocomposites because of its high mechanical strength, excellent electrical conductivity and plentiful availability (from graphite). In this review, the preparation methods of graphene/polymer nanocomposites, including solution blending, melt blending and in situ polymerization, are introduced in order to study the relationship between these methods and the final characteristics and properties. Each method has an influence on the final characteristics and properties of the nanocomposites. The advantages and disadvantages of these methods are discussed. In addition, a variety of nanocomposites with different properties, such as mechanical properties, electronic conductivity, thermal conductivity and thermal properties, are summarized comprehensively. The potential applications of these nanocomposites in conductive materials, electromagnetic shielding materials, photocatalytic materials and so on, are briefly presented. This review demonstrates that polymer/graphene nanocomposites exhibit superior comprehensive performance and will be applied in the fields of new materials and novel devices. Future research directions of the nanocomposites are also presented.

Vibration Characteristics of 3D Printed Viscoelastic Graded Polymeric Plates

2021 ◽  
Author(s):  
Justin Carter ◽  
Kumar Vikram Singh ◽  
Fazeel Khan
Keyword(s):  
3D Printing ◽  
Fused Deposition Modeling ◽  
Polymeric Materials ◽  
Vibration Characteristics ◽  
Thin Plates ◽  
Future Research ◽  
Structural Components ◽  
Processing Technologies ◽  
Fused Deposition ◽  
Multiple Materials

Abstract The exploration of structures made of multiple materials is a growing area of research as additive manufacturing processing technologies such as fused deposition modeling (FDM) 3D printing allows for their fabrication. Such a technology allows for rapid prototyping of structural components with complex geometries or spatially distributed materials with different properties and functionalities. By selecting suitable spatial distribution of materials, the performance of structural components can be manipulated and enhanced as per different engineering application needs. For a low-cost design of structural prototypes using 3D printing processes, viscoelastic polymeric materials are often used, having inherent damping properties. In this research, vibration characteristics of thin plates which are axially graded with multiple polymeric materials are investigated. The goal is to understand the influence of material grading on the frequency and damping characteristics of graded plates. Although in literature, material grading along the thickness in designing composite laminates and their vibration characteristics are available, the performance of plates having axially graded viscoelastic polymers have not been investigated yet. Through systematic modeling and experimental plans, vibration characteristics of axially graded viscoelastic plates are presented here. In particular, the damping performance for different grading schemes is evaluated. It is anticipated that such analysis will allow accurate modeling and testing of design prototypes of structural components for future research, such as design and testing of graded panels for enhanced flutter characteristics.

Production Techniques of Metallic Foams in Lightweight Materials

2022 ◽  
pp. 153-175
Author(s):  
Nuray Beköz Üllen ◽  
Gizem Karabulut
Keyword(s):  
Physical State ◽  
Metallic Foam ◽  
Metallic Foams ◽  
Production Technique ◽  
Lightweight Materials ◽  
Production Methods ◽  
Ionic State ◽  
Production Techniques ◽  
State Production ◽  
Usage Area

Lightweight materials were needed in many different areas, especially in order to reduce the required energy in areas such as automotive and aerospace industries. Metallic foams attract attention in lightweight material applications due to their unique properties. The pores in its structure provide advantages in many applications, both structural and functional by promising both ultra-lightweight construction, energy absorption, and damping insulation. Production techniques of metallic foams can generally be classified as liquid, solid, gas, and ionic state production according to the physical state of the metal at the beginning of the process. The production technique should be chosen according to the usage area and desired properties of the metallic foam and the suitability in terms of cost and sustainability of production. For this reason, the details of the production techniques should be known and the products that can be obtained and their properties should be understood. In this respect, this chapter emphasizes the production methods from past to present.

scholarly journals Physical and Chemical Modifications of Plant Fibres for Reinforcement in Cementitious Composites

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
R. Ahmad ◽  
R. Hamid ◽  
S. A. Osman
Keyword(s):  
Mechanical Properties ◽  
Interfacial Adhesion ◽  
Moisture Absorption ◽  
Surface Modifications ◽  
Future Research ◽  
Cementitious Composites ◽  
Chemical Surface ◽  
Plant Fibre ◽  
Physical And Chemical ◽  
Fibre Matrix

This paper highlights the physical and chemical surface modifications of plant fibre (PF) for attaining suitable properties as reinforcements in cementitious composites. Untreated PF faces insufficient adhesion between the fibres and matrix due to high levels of moisture absorption and poor wettability. These conditions accelerate degradation of the fibre in the composite. It is also essential to reduce the risk of hydrophilic PF conditions with surface modification, to enhance the mechanical properties of the fibres. Fibres that undergo chemical and physical modifications had been proven to exhibit improved fibre-matrix interfacial adhesion in the composite and contribute to better composite mechanical properties. This paper also gives some recommendations for future research on chemical and physical modifications of PF.

Electronic and Optoelectronic Devices Based on GaN-AIGaN Heterostructures

1994 ◽  
Vol 339 ◽  
Author(s):  
M. Asif Khan ◽  
J. N. Kuznia ◽  
S. Krishnankutty ◽  
R. A. Skogman ◽  
D. T. Olson ◽  
...  
Keyword(s):  
Solid State ◽  
Data Storage ◽  
High Power ◽  
Oil And Gas ◽  
Optical Data Storage ◽  
Optical Data ◽  
Future Research ◽  
Material System ◽  
Ir Radiation ◽  
Processing Technologies

ABSTRACTAvailability of optoelectronic components operating in the U V-Visible part of the spectrum opens several exciting and important system applications. Solid state ultraviolet and blue-green lasers can increase the optical data storage density of CDROM/WORM and magneto-optical disks by a factor of four. They are also ideally suited for environmental pollutant identification and monitoring. On the other hand, solid state ultraviolet detectors that do not respond to visible or IR radiation are highly desirable for various commercial systems. These include medical imaging, industrial boiler systems, fire/flame safeguard systems around oil and gas installations and several military applications. A key requirement for these ultraviolet laser and sensor devices is the availability of a semiconductor material system with high quality controlled doping and fabrication technology.AlxGa1−xN and InxGa1−xN for which the direct bandgap can be tailored from the visible to the deep UV is such a material system. Ours and several other research groups (nationally and internationally) have been developing AlxGa1−xN materials and processing technologies over the past several years. Recently, by employing innovative approaches, significant advances have been made in heteroepitaxy of AlxGa1−xN on sapphire substrates. Also, controlled n and p-type doping has been achieved. Several high performance devices that form the basis of exciting future research have been demonstrated. These include high responsivity visible blind ultraviolet sensors, basic transistor structures and high power blue light emitting diodes. These pave the way for future research leading to exciting products such as blue-green lasers and UV-imaging arrays. The demonstrated transistor structures are foundation for building AlxGa1−xN -GaN based high power, high frequency and high temperature electronic components. In this paper, we will summarize some of our recent work and reflect on the potential and the issues in AlxGa1−xN-InxGa1−xN based device development.

scholarly journals Bone Regeneration in Critical-Sized Bone Defects Treated with Additively Manufactured Porous Metallic Biomaterials: The Effects of Inelastic Mechanical Properties

Materials ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1992
Author(s):  
Marianne Koolen ◽  
Saber Amin Yavari ◽  
Karel Lietaert ◽  
Ruben Wauthle ◽  
Amir A. Zadpoor ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Bone Regeneration ◽  
Bone Tissue ◽  
Tissue Regeneration ◽  
Bulk Material ◽  
Bone Tissue Regeneration ◽  
Bony Tissue ◽  
Metallic Biomaterials ◽  
Cp Ti ◽  
Porous Biomaterials

Additively manufactured (AM) porous metallic biomaterials, in general, and AM porous titanium, in particular, have recently emerged as promising candidates for bone substitution. The porous design of such materials allows for mimicking the elastic mechanical properties of native bone tissue and showed to be effective in improving bone regeneration. It is, however, not clear what role the other mechanical properties of the bulk material such as ductility play in the performance of such biomaterials. In this study, we compared the bone tissue regeneration performance of AM porous biomaterials made from the commonly used titanium alloy Ti6Al4V-ELI with that of commercially pure titanium (CP-Ti). CP-Ti was selected because of its high ductility as compared to Ti6Al4V-ELI. Critical-sized (6 mm diameter) femoral defects in rats were treated with implants made from both Ti6Al4V-ELI and CP-Ti. Bone regeneration was assessed up to 11 weeks using micro-CT scanning. The regenerated bone volume was assessed ex vivo followed by histology and biomechanical testing to assess osseointegration of the implants. The bony defects treated with AM CP-Ti implants generally showed higher volumes of regenerated bone as compared to those treated with AM Ti6Al4V-ELI. The torsional strength of the two titanium groups were similar however, and both considerably lower than those measured for intact bony tissue. These findings show the importance of material type and ductility of the bulk material in the ability for bone tissue regeneration of AM porous biomaterials.

Mesoscopic investigation of layered graded metallic foams under dynamic compaction

2018 ◽  
Vol 21 (14) ◽  
pp. 2081-2098 ◽  
Author(s):  
Jinhua Zhang ◽  
Yadong Zhang ◽  
Junyu Fan ◽  
Qin Fang ◽  
Yuan Long
Keyword(s):  
Impact Loading ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Metallic Foam ◽  
Layer By Layer ◽  
Metallic Foams ◽  
Mesoscopic Model ◽  
Layer Arrangement ◽  
Computed Tomography Images ◽  
Closed Cell

This article is aimed to reveal the dynamic response of layered graded metallic foam under impact loading using a three-dimensional mesoscopic model. First, a mesoscopic model for closed-cell metallic foam is proposed based on the X-ray computed tomography images. Second, a numerical analysis approach is presented and validated with test data. Third, it studies the dynamic behavior of the layered graded metallic foam under impact loading numerically. The metallic foam specimen is composed layer by layer. The porosity, which is a fraction of the voids volume over the total volume, is different with each other for the layers. Simulations are conducted to the specimen with increasing and decreasing porosity arrangement. Results show that the layer arrangement is critical to the dynamic properties. The mesoscopic deformation of cell walls and the energy absorption capability are also affected significantly. This article gives insights into the mechanical properties and mesoscopic deformation of layered graded metallic foam.

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