Evaluation of Thermal Properties and Physical Aging as Function of the Pendent Chain Length in Tyrosine-Derived Polycarbonates, a Class of New Biomaterials

1995 ◽  
Vol 394 ◽  
Author(s):  
Varawut Tangpasuthadol ◽  
Adi Shefer ◽  
Kimberly A. Hooper ◽  
Joachim Kohn
Keyword(s):  
Thermal Properties ◽  
Chain Length ◽  
Biomedical Applications ◽  
Physical Aging ◽  
Polymer Structure ◽  
Model System ◽  
Relaxation Kinetics ◽  
Polymer Properties ◽  
Wide Range ◽  
Biomedical Polymers

Tyrosine-derived polycarbonates are currently in preclinical evaluations for biomedical applications. Although physical aging can significantly alter a wide range of polymer properties, physical aging is has rarely been investigated for biomedical polymers. A series of four tyrosinederived polycarbonates was used as a model system to study the effect of polymer structure on the enthalpy relaxation kinetics.

The Relations between Polymer Structure and Properties in Urethans

1960 ◽  
Vol 33 (5) ◽  
pp. 1259-1292 ◽  
Author(s):  
J. H. Saunders
Keyword(s):  
Polymer Structure ◽  
Future Research ◽  
Reliable Control ◽  
Structure And Properties ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Precise Knowledge ◽  
Polymer Properties ◽  
Wide Range ◽  
The Many

Abstract Sufficient data are available from studies of urethan foams and elastomers to draw semiquantitative conclusions regarding the effect of any gross structural change on most polymer properties. These relationships apply to other areas of application as well, e.g., coatings, adhesives and sealants. Future research may be expected to provide more reliable control of the many reactions involved in preparing urethans, thus better control over structure. Similarly a more quantitative and extensive knowledge of polymer properties may be expected. The result of these combined efforts will be a more precise knowledge of structure-property relationships and an improved ability to produce polymers having the properties desired for a wide range of applications.

The Relation between Structure and Physical Properties in Polyurethans

1962 ◽  
Vol 35 (4) ◽  
pp. 970-1012 ◽  
Author(s):  
Takehide Tanaka ◽  
Tetsuo Yokoyama
Keyword(s):  
Physical Properties ◽  
Polymer Structure ◽  
Structure And Properties ◽  
Structure Property ◽  
Chemical Structures ◽  
Structure Property Relationships ◽  
Polymer Properties ◽  
Wide Range ◽  
Number Of Publications ◽  
Broad Region

Abstract The field of polyurethans is rapidly growing in commercial importance, especially in form and elastomer applications. This group of polymers includes a very broad region of chemical structures and chain length. In many cases polyurethans are synthesized from polyester glycols or polyether glycols and diisocyanates so that the urethan groups are even fewer in number than other functional groups. This process of synthesis enables us to deal with a very wide range of polymer properties, adding interest to the studies of relation between structure and properties. Though a considerable number of publications dealing primarily with the properties of urethan polymers have been published, few of them contribute to better understanding of the relation between these properties and the corresponding polymer structure. Within the last few years information of value has become available, and Saunders has established some semi-quantitative relations by the use of such data. He also discusses in his reports general considerations concerning structure-property relationships. Although his considerations and conclusions show a marked progress, they are not theoretically satisfactory yet, especially from a quantitative viewpoint. The authors have investigated structure-property relationships in polyurethans for a few years and written some papers concerning synthesis, reaction kinetics, some physical properties, network structure, and dynamic behavior of polyurethans.

Rheological and Thermal Properties of a Model System for PIM

2009 ◽  
Vol 24 (2) ◽  
pp. 206-212 ◽  
Author(s):  
H. Persson ◽  
B. Hausnerová ◽  
L. Nyborg ◽  
M. Rigdahl
Keyword(s):  
Thermal Properties ◽  
Model System

Graphene and Graphene-Based Materials in Biomedical Applications

2019 ◽  
Vol 26 (38) ◽  
pp. 6834-6850 ◽  
Author(s):  
Mohammad Omaish Ansari ◽  
Kalamegam Gauthaman ◽  
Abdurahman Essa ◽  
Sidi A. Bencherif ◽  
Adnan Memic
Keyword(s):  
Tissue Engineering ◽  
Thermal Properties ◽  
Gene Delivery ◽  
Regenerative Medicine ◽  
Biomedical Research ◽  
Biomedical Applications ◽  
Biomedical Application ◽  
Two Dimensional ◽  
Drug And Gene Delivery ◽  
Biomedical Fields

: Nanobiotechnology has huge potential in the field of regenerative medicine. One of the main drivers has been the development of novel nanomaterials. One developing class of materials is graphene and its derivatives recognized for their novel properties present on the nanoscale. In particular, graphene and graphene-based nanomaterials have been shown to have excellent electrical, mechanical, optical and thermal properties. Due to these unique properties coupled with the ability to tune their biocompatibility, these nanomaterials have been propelled for various applications. Most recently, these two-dimensional nanomaterials have been widely recognized for their utility in biomedical research. In this review, a brief overview of the strategies to synthesize graphene and its derivatives are discussed. Next, the biocompatibility profile of these nanomaterials as a precursor to their biomedical application is reviewed. Finally, recent applications of graphene-based nanomaterials in various biomedical fields including tissue engineering, drug and gene delivery, biosensing and bioimaging as well as other biorelated studies are highlighted.

scholarly journals Recent trends in smartphone-based detection for biomedical applications: a review

2021 ◽  
Vol 413 (9) ◽  
pp. 2389-2406 ◽  
Author(s):  
Soumyabrata Banik ◽  
Sindhoora Kaniyala Melanthota ◽  
Arbaaz ◽  
Joel Markus Vaz ◽  
Vishak Madhwaraj Kadambalithaya ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Histopathological Examination ◽  
Dark Field ◽  
Portable Devices ◽  
Food Technology ◽  
Wide Range ◽  
Technological Interventions ◽  
Recent Trends ◽  
Increasing Demand

AbstractSmartphone-based imaging devices (SIDs) have shown to be versatile and have a wide range of biomedical applications. With the increasing demand for high-quality medical services, technological interventions such as portable devices that can be used in remote and resource-less conditions and have an impact on quantity and quality of care. Additionally, smartphone-based devices have shown their application in the field of teleimaging, food technology, education, etc. Depending on the application and imaging capability required, the optical arrangement of the SID varies which enables them to be used in multiple setups like bright-field, fluorescence, dark-field, and multiple arrays with certain changes in their optics and illumination. This comprehensive review discusses the numerous applications and development of SIDs towards histopathological examination, detection of bacteria and viruses, food technology, and routine diagnosis. Smartphone-based devices are complemented with deep learning methods to further increase the efficiency of the devices.

scholarly journals CeO2 Nanoparticle-Containing Polymers for Biomedical Applications: A Review

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 924
Author(s):  
Alexander B. Shcherbakov ◽  
Vladimir V. Reukov ◽  
Alexander V. Yakimansky ◽  
Elena L. Krasnopeeva ◽  
Olga S. Ivanova ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Metal Oxide Nanoparticles ◽  
Polymeric Materials ◽  
Negative Effects ◽  
New Horizons ◽  
Beneficial Effects ◽  
Advanced Composite ◽  
Unique Material ◽  
Biomedical Polymers ◽  
Biomedical Potential

The development of advanced composite biomaterials combining the versatility and biodegradability of polymers and the unique characteristics of metal oxide nanoparticles unveils new horizons in emerging biomedical applications, including tissue regeneration, drug delivery and gene therapy, theranostics and medical imaging. Nanocrystalline cerium(IV) oxide, or nanoceria, stands out from a crowd of other metal oxides as being a truly unique material, showing great potential in biomedicine due to its low systemic toxicity and numerous beneficial effects on living systems. The combination of nanoceria with new generations of biomedical polymers, such as PolyHEMA (poly(2-hydroxyethyl methacrylate)-based hydrogels, electrospun nanofibrous polycaprolactone or natural-based chitosan or cellulose, helps to expand the prospective area of applications by facilitating their bioavailability and averting potential negative effects. This review describes recent advances in biomedical polymeric material practices, highlights up-to-the-minute cerium oxide nanoparticle applications, as well as polymer-nanoceria composites, and aims to address the question: how can nanoceria enhance the biomedical potential of modern polymeric materials?

scholarly journals Effects of a Twin-Screw Extruder Equipped with a Molten Resin Reservoir on the Mechanical Properties and Microstructure of Recycled Waste Plastic Polyethylene Pellet Moldings

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1058
Author(s):  
Hikaru Okubo ◽  
Haruka Kaneyasu ◽  
Tetsuya Kimura ◽  
Patchiya Phanthong ◽  
Shigeru Yao
Keyword(s):  
Mechanical Properties ◽  
Mechanical Performance ◽  
Value Added ◽  
Industrial Applications ◽  
Twin Screw Extruder ◽  
Screw Extruder ◽  
Polymer Properties ◽  
Wide Range ◽  
Twin Screw ◽  
Recycled Plastics

Each year, increasing amounts of plastic waste are generated, causing environmental pollution and resource loss. Recycling is a solution, but recycled plastics often have inferior mechanical properties to virgin plastics. However, studies have shown that holding polymers in the melt state before extrusion can restore the mechanical properties; thus, we propose a twin-screw extruder with a molten resin reservoir (MSR), a cavity between the screw zone and twin-screw extruder discharge, which retains molten polymer after mixing in the twin-screw zone, thus influencing the polymer properties. Re-extruded recycled polyethylene (RPE) pellets were produced, and the tensile properties and microstructure of virgin polyethylene (PE), unextruded RPE, and re-extruded RPE moldings prepared with and without the MSR were evaluated. Crucially, the elongation at break of the MSR-extruded RPE molding was seven times higher than that of the original RPE molding, and the Young’s modulus of the MSR-extruded RPE molding was comparable to that of the virgin PE molding. Both the MSR-extruded RPE and virgin PE moldings contained similar striped lamellae. Thus, MSR re-extrusion improved the mechanical performance of recycled polymers by optimizing the microstructure. The use of MSRs will facilitate the reuse of waste plastics as value-added materials having a wide range of industrial applications.

scholarly journals Engineering the Monomer Composition of Polyhydroxyalkanoates Synthesized in Saccharomyces cerevisiae

2006 ◽  
Vol 72 (1) ◽  
pp. 536-543 ◽  
Author(s):  
Bo Zhang ◽  
Ross Carlson ◽  
Friedrich Srienc
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Fatty Acid ◽  
Chain Length ◽  
Fatty Acid Metabolism ◽  
Acid Metabolism ◽  
Pha Synthase ◽  
Fatty Acid Degradation ◽  
Medium Chain ◽  
Acid Degradation ◽  
Wide Range

ABSTRACT Polyhydroxyalkanoates (PHAs) have received considerable interest as renewable-resource-based, biodegradable, and biocompatible plastics with a wide range of potential applications. We have engineered the synthesis of PHA polymers composed of monomers ranging from 4 to 14 carbon atoms in either the cytosol or the peroxisome of Saccharomyces cerevisiae by harnessing intermediates of fatty acid metabolism. Cytosolic PHA production was supported by establishing in the cytosol critical β-oxidation chemistries which are found natively in peroxisomes. This platform was utilized to supply medium-chain (C6 to C14) PHA precursors from both fatty acid degradation and synthesis to a cytosolically expressed medium-chain-length (mcl) polymerase from Pseudomonas oleovorans. Synthesis of short-chain-length PHAs (scl-PHAs) was established in the peroxisome of a wild-type yeast strain by targeting the Ralstonia eutropha scl polymerase to the peroxisome. This strain, harboring a peroxisomally targeted scl-PHA synthase, accumulated PHA up to approximately 7% of its cell dry weight. These results indicate (i) that S. cerevisiae expressing a cytosolic mcl-PHA polymerase or a peroxisomal scl-PHA synthase can use the 3-hydroxyacyl coenzyme A intermediates from fatty acid metabolism to synthesize PHAs and (ii) that fatty acid degradation is also possible in the cytosol as β-oxidation might not be confined only to the peroxisomes. Polymers of even-numbered, odd-numbered, or a combination of even- and odd-numbered monomers can be controlled by feeding the appropriate substrates. This ability should permit the rational design and synthesis of polymers with desired material properties.

Recent advances in the design of inorganic and nano-clay particles for the treatment of brain disorders

2021 ◽  
Author(s):  
Francesca Persano ◽  
Svetlana Batasheva ◽  
Gölnur Fakhrullina ◽  
Giuseppe Gigli ◽  
Stefano Leporatti ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Silica Nanoparticles ◽  
Biomedical Applications ◽  
Inorganic Materials ◽  
Brain Disorders ◽  
Clay Particles ◽  
Recent Advances ◽  
Wide Range ◽  
Nano Clay

Inorganic materials, in particular nanoclays and silica nanoparticles, have attracted enormous attention due to their versatile and tuneable properties, making them ideal candidates for a wide range of biomedical applications, such as drug delivery.

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