scholarly journals Design of Thermoplastic 3D-Printed Scaffolds for Bone Tissue Engineering: Influence of Parameters of “Hidden” Importance in the Physical Properties of Scaffolds

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1546 ◽  
Author(s):  
Nieves Cubo-Mateo ◽  
Luis M. Rodríguez-Lorenzo
Keyword(s):  
Tissue Engineering ◽  
Room Temperature ◽  
Mechanical Performance ◽  
Starting Point ◽  
Final Porosity ◽  
3D Printed ◽  
The Common ◽  
Nozzle Temperature ◽  
Forced Cooling

Additive manufacturing (AM) techniques are becoming the approaches of choice for the construction of scaffolds in tissue engineering. However, the development of 3D printing in this field brings unique challenges, which must be accounted for in the design of experiments. The common printing process parameters must be considered as important factors in the design and quality of final 3D-printed products. In this work, we study the influence of some parameters in the design and fabrication of PCL scaffolds, such as the number and orientation of layers, but also others of “hidden” importance, such as the cooling down rate while printing, or the position of the starting point in each layer. These factors can have an important impact oin the final porosity and mechanical performance of the scaffolds. A pure polycaprolactone filament was used. Three different configurations were selected for the design of the internal structure of the scaffolds: a solid one with alternate layers (solid) (0°, 90°), a porous one with 30% infill and alternate layers (ALT) (0°, 90°) and a non-alternated configuration consisting in printing three piled layers before changing the orientation (n-ALT) (0°, 0°, 0°, 90°, 90°, 90°). The nozzle temperature was set to 172 °C for printing and the build plate to 40 °C. Strand diameters of 361 ± 26 µm for room temperature cooling down and of 290 ± 30 µm for forced cooling down, were obtained. A compression elastic modulus of 2.12 ± 0.31 MPa for n-ALT and 8.58 ± 0.14 MPa for ALT scaffolds were obtained. The cooling down rate has been observed as an important parameter for the final characteristics of the scaffold.

Biomimetic Design of 3D Printed Tissue-engineered bone Constructs

2020 ◽  
Vol 16 ◽  
Author(s):  
Wei Liu ◽  
Shifeng Liu ◽  
Yunzhe Li ◽  
Peng Zhou ◽  
Qian ma
Keyword(s):  
Tissue Engineering ◽  
3D Printing ◽  
Advanced Materials ◽  
Bionic Design ◽  
Material Interfaces ◽  
Precise Control ◽  
Cell Printing ◽  
Biomimetic Scaffolds ◽  
3D Printed

Abstract:: Surgery to repair damaged tissue, which is caused by disease or trauma, is being carried out all the time, and a desirable treatment is compelling need to regenerate damaged tissues to further improve the quality of human health. Therefore, more and more research focus on exploring the most suitable bionic design to enrich available treatment methods. 3D-printing, as an advanced materials processing approach, holds promising potential to create prototypes with complex constructs that could reproduce primitive tissues and organs as much as possible or provide appropriate cell-material interfaces. In a sense, 3D printing promises to bridge between tissue engineering and bionic design, which can provide an unprecedented personalized recapitulation with biomimetic function under the precise control of the composition and spatial distribution of cells and biomaterials. This article describes recent progress in 3D bionic design and the potential application prospect of 3D printing regenerative medicine including 3D printing biomimetic scaffolds and 3D cell printing in tissue engineering.

scholarly journals Silicate-Based Electro-Conductive Inks for Printing Soft Electronics and Tissue Engineering

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 240
Author(s):  
Sadaf Samimi Gharaie ◽  
Amir Seyfoori ◽  
Bardia Khun Jush ◽  
Xiong Zhou ◽  
Erik Pagan ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Flexible Electronics ◽  
Mechanical Performance ◽  
Wearable Sensors ◽  
Three Dimensional ◽  
Tensile Tests ◽  
Rheological Characterization ◽  
Mechanical And Electrical Properties ◽  
3D Printed ◽  
Extrusion Printing

Hydrogel-based bio-inks have been extensively used for developing three-dimensional (3D) printed biomaterials for biomedical applications. However, poor mechanical performance and the inability to conduct electricity limit their application as wearable sensors. In this work, we formulate a novel, 3D printable electro-conductive hydrogel consisting of silicate nanosheets (Laponite), graphene oxide, and alginate. The result generated a stretchable, soft, but durable electro-conductive material suitable for utilization as a novel electro-conductive bio-ink for the extrusion printing of different biomedical platforms, including flexible electronics, tissue engineering, and drug delivery. A series of tensile tests were performed on the material, indicating excellent stability under significant stretching and bending without any conductive or mechanical failures. Rheological characterization revealed that the addition of Laponite enhanced the hydrogel’s mechanical properties, including stiffness, shear-thinning, and stretchability. We also illustrate the reproducibility and flexibility of our fabrication process by extrusion printing various patterns with different fiber diameters. Developing an electro-conductive bio-ink with favorable mechanical and electrical properties offers a new platform for advanced tissue engineering.

scholarly journals Recovering the Common Good: The Key to a truly Prosperous Society?

2013 ◽  
Vol 44 (2) ◽  
pp. 319
Author(s):  
Andrew Bradstock
Keyword(s):  
New Zealand ◽  
Common Good ◽  
Social Teaching ◽  
The Good Life ◽  
Common Life ◽  
The Common Good ◽  
Starting Point ◽  
The Common ◽  
Definition Of

This article argues that the common good would have much to contribute to political discourse in New Zealand at the present time. Beginning with a definition of the concept, particularly as it has developed within Catholic Social Teaching, the article examines attempts by New Zealand church leaders to introduce it into public debate in recent decades, and concludes that, were the common good to be given serious consideration today, it would both prompt New Zealanders to look critically at their society and consider the purpose of their common life together, and enhance their quality of life individually and communally. The article addresses the charge that promoting the common good might be seen as favouring one (religiously-inspired) notion of 'the good life' over others, and, following Raymond Plant, suggests that, in a pluralist society, a more appropriate starting point for a conversation about such issues would be an exploration of 'social justice'. The article also explores the extent to which markets and governments might promote the common good.

scholarly journals Carrying out systematic literature reviews: an introduction

2019 ◽  
Vol 28 (15) ◽  
pp. 1008-1014 ◽  
Author(s):  
Alan Davies
Keyword(s):  
Systematic Review ◽  
Review Process ◽  
Clinical Decision Making ◽  
Clinical Decision ◽  
Starting Point ◽  
Literature Reviews ◽  
Good Starting Point ◽  
The Common ◽  
Systematic Review Process

Systematic reviews provide a synthesis of evidence for a specific topic of interest, summarising the results of multiple studies to aid in clinical decisions and resource allocation. They remain among the best forms of evidence, and reduce the bias inherent in other methods. A solid understanding of the systematic review process can be of benefit to nurses that carry out such reviews, and for those who make decisions based on them. An overview of the main steps involved in carrying out a systematic review is presented, including some of the common tools and frameworks utilised in this area. This should provide a good starting point for those that are considering embarking on such work, and to aid readers of such reviews in their understanding of the main review components, in order to appraise the quality of a review that may be used to inform subsequent clinical decision making.

scholarly journals Sustainability of the city and its ecological footprint

Spatium ◽  
2004 ◽  
pp. 48-52
Author(s):  
Jasna Petric
Keyword(s):  
Ecological Footprint ◽  
Bottom Line ◽  
Sustainable City ◽  
Mixed Use ◽  
Starting Point ◽  
Target Values ◽  
The Common ◽  
The One ◽  
The City

There are some agreed sustainability indicators, even some agreed target values regarding a sustainable city, but they still have to be underpinned by empirical evidence. The common starting point of definitions is generally the destructive impact of the city on its regional and global environment which can be observed in form of the depletion of natural resources and the pollution of soil, water and air. A sustainable city is therefore generally regarded to be the one that is compact and preserves land, has mixed use to increase access and reduce need to travel, is socially and economically balanced, uses clean and renewable energy and recycles all its waste. However, the sustainable city cannot exist as a self-sufficient unit, in ignorance of relationship with its hinterland. The ecological footprint which is the amount of land required to produce resources to sustain our quality of life is a yardstick for measuring the ecological bottom line of sustainability. With a sustainable city target to relieve pressure on the countryside, there is an increasing awareness of the importance of calculating city?s ecological footprint and see how it relates to the target global average. Although problem of reducing ecological footprints primarily concerns the wealthiest countries, it has to be fully acknowledged in the less economically developed part of the world, while recognising that cities themselves provide many potential solutions.

The concept of motivation for effective credit risk management

2020 ◽  
Vol 26 (11) ◽  
pp. 2567-2593
Author(s):  
M.V. Pomazanov
Keyword(s):  
Risk Management ◽  
Economic Modeling ◽  
Type I ◽  
Credit Risk Management ◽  
Curve Modeling ◽  
Business Functions ◽  
The Common ◽  
Lending Decisions ◽  
The One

Subject. The study addresses the improvement of risk management efficiency and the quality of lending decisions made by banks. Objectives. The aim is to present the bank management with a fair algorithm for risk management motivation on the one hand, and the credit management (business) on the other hand. Within the framework of the common goal to maximize risk-adjusted income from loans, this algorithm will provide guidelines for ‘risk management’ and ‘business’ functions on how to improve individual and overall efficiency. Methods. The study employs the discriminant analysis, type I and II errors, Lorentz curve modeling, statistical analysis, economic modeling. Results. The paper offers a mechanism for assessing the quality of risk management decisions as opposed to (or in support of) decisions of the lending business when approving transactions. The mechanism rests on the approach of stating type I and II errors and the corresponding classical metric of the Gini coefficient. On the ‘business’ side, the mechanism monitors the improvement or deterioration of the indicator of changes in losses in comparison with the market average. Conclusions. The study substantiates the stimulating ‘rules of the game’ between the ‘business’ and ‘risk management’ to improve the efficiency of the entire business, to optimize interactions within the framework of internal competition. It presents mathematical tools to calculate corresponding indicators of the efficiency of internally competing entities.

THE STUDY ON TA VAT WINE PRODUCTION FROM SUGAR PALM (ARENGA PINNATA) SAP

2014 ◽  
Vol 83 (5) ◽  
Author(s):  
Nguyễn Thị Hồng Thu ◽  
Đặng Minh Nhật ◽  
Nguyễn Hoàng Dung
Keyword(s):  
Room Temperature ◽  
Fermentation Process ◽  
Inoculum Size ◽  
Wine Fermentation ◽  
Wine Production ◽  
Factors Affecting ◽  
Natural Fermentation ◽  
Tropical Asia ◽  
Best Parameters

Sugar palm (Arenga pinnata) is a feather palm native to tropical Asia. In Vietnam, it is named Búng Báng or Đoác and grown only on the highlands in the central or northern part of Vietnam. It is utilized for many purposes, especially for Ta Vat wine production - a characteristic and unique product of Co Tu ethnic minority. However, because of the natural fermentation used in the production, the product quality is inconsistent. The purpose of this study was to examine a new procedure of using palm sap for making Ta Vat wine. Some characteristics of the sap, which was collected at Nam Giang district, Quang Nam province are determined, proving the potential of the sap for making wine product. The quality of sap changes quickly at room temperature. At low temperature (4 - 60C), the changes in sap quality are apparently slower. Examining some factors affecting its quality during the wine fermentation process, we determined the best parameters for the fermentation process as follows: inoculum size of 3% with cell density of about 1x108 cells/ml, the addition of the extract from the bark of Ceylon ironwood (Mesua ferrea L.) 4%. Keywords: Arenga pinnata, sap, Ceylon ironwood bark, Mesua ferrea L., wine fermentation.

The Still Life of Objects – Heidegger, Schapiro, and Derrida reconsidered

2015 ◽  
Vol 60 (1) ◽  
pp. 81-102
Author(s):  
KErstin Thomas
Keyword(s):  
Still Life ◽  
Work Of Art ◽  
Concrete Material ◽  
Vincent Van Gogh ◽  
Starting Point ◽  
Specific Object ◽  
Truth Claims ◽  
The Common ◽  
Critical Intervention ◽  
The Given

Kerstin Thomas revaluates the famous dispute between Martin Heidegger, Meyer Schapiro, and Jacques Derrida, concerning a painting of shoes by Vincent Van Gogh. The starting point for this dispute was the description and analysis of things and artworks developed in his essay, “The Origin of the Work of Art”. In discussing Heidegger’s account, the art historian Meyer Schapiro’s main point of critique concerned Heidegger’s claim that the artwork reveals the truth of equipment in depicting shoes of a peasant woman and thereby showing her world. Schapiro sees a striking paradox in Heidegger’s claim for truth, based on a specific object in a specific artwork while at the same time following a rather metaphysical idea of the artwork. Kerstin Thomas proposes an interpretation, which exceeds the common confrontation of philosophy versus art history by focussing on the respective notion of facticity at stake in the theoretical accounts of both thinkers. Schapiro accuses Heidegger of a lack of concreteness, which he sees as the basis for every truth claim on objects. Thomas understands Schapiro’s objections as motivated by this demand for a facticity, which not only includes the work of art, but also investigator in his concrete historical perspective. Truth claims under such conditions of facticity are always relative to historical knowledge, and open to critical intervention and therefore necessarily contingent. Following Thomas, Schapiro’s critique shows that despite his intention of giving the work of art back its autonomy, Heidegger could be accused of achieving quite the opposite: through the abstraction of the concrete, the factual, and the given to the type, he actually sets the self and the realm of knowledge of the creator as absolute and not the object of his knowledge. Instead, she argues for a revaluation of Schapiro’s position with recognition of the arbitrariness of the artwork, by introducing the notion of factuality as formulated by Quentin Meillassoux. Understood as exchange between artist and object in its concrete material quality as well as with the beholder, the truth of painting could only be shown as radically contingent. Thomas argues that the critical intervention of Derrida who discusses both positions anew is exactly motivated by a recognition of the contingent character of object, artwork and interpretation. His deconstructive analysis can be understood as recognition of the dynamic character of things and hence this could be shown with Meillassoux to be exactly its character of facticity – or factuality.

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