scholarly journals Fibrin-based Bioinks: New Tricks from an Old Dog

2020 ◽  
Vol 6 (3) ◽  
Author(s):  
Anastasia Shpichka ◽  
Daria Osipova ◽  
Yuri Efremov ◽  
Polina Bikmulina ◽  
Nastasia Kosheleva ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Tissue Specific ◽  
Research Teams ◽  
The Past ◽  
Set Up

For the past 10 years, the main efforts of most bioprinting research teams have focused on creating new bioinkformulations, rather than inventing new printing set-up concepts. New tissue-specific bioinks with good printability, shapefidelity, and biocompatibility are based on “old” (well-known) biomaterials, particularly fibrin. While the interest in fibrinbased bioinks is constantly growing, it is essential to provide a framework of material’s properties and trends. This review aimsto describe the fibrin properties and application in three-dimensional bioprinting and provide a view on further developmentof fibrin-based bioinks

scholarly journals Comparison of Achievable Contrast Features in Computed Tomography Observing the Growth of a 4H-SiC Bulk Crystal

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3652
Author(s):  
Michael Salamon ◽  
Matthias Arzig ◽  
Peter J. Wellmann ◽  
Norman Uhlmann
Keyword(s):  
Computed Tomography ◽  
Rayleigh Scattering ◽  
Three Dimensional ◽  
Helical Ct ◽  
Photoelectric Effect ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Past ◽  
Material Contrast ◽  
Set Up

Today the physical vapor transport process is regularly applied for the growth of bulk SiC crystals. Due to the required high temperature of up to 2400 °C, and low gas pressure of several Mbar inside the crucible, the systems are encapsulated by several layers for heating, cooling and isolation inhibiting the operator from observing the growth. Also, the crucible itself is fully encapsulated to avoid impurities from being inserted into the crystal or disturbing the temperature field distribution. Thus, once the crucible has been set up with SiC powder and the seed crystal, the visible access to the progress of growth is limited. In the past, X-ray radiography has allowed this limitation to be overcome by placing the crucible in between an X-ray source and a radiographic film. Recently these two-dimensional attenuation signals have been extended to three-dimensional density distribution by the technique of computed tomography (CT). Beside the classic X-ray attenuation signal dominated by photoelectric effect, Compton effect and Rayleigh scattering, X-ray diffraction resulting in the crystalline structure of the 4H-SiC superimposes the reconstructed result. In this contribution, the achievable material contrast related to the level of X-ray energy and the absorption effects is analyzed using different CT systems with energies from 125 kV to 9 MeV. Furthermore the X-ray diffraction influence is shown by the comparison between the advanced helical-CT method and the classical 3D-CT.

Mitochondrial Reconstructions Based on Serial Thick Sections and HVEM

1975 ◽  
Vol 33 ◽  
pp. 286-287
Author(s):  
Jerome J. Paulin
Keyword(s):  
Imaging Techniques ◽  
Three Dimensional ◽  
Posterior Pole ◽  
Dimensional Structure ◽  
Stereo Imaging ◽  
Thin Sections ◽  
Anatomical Features ◽  
The Past ◽  
Cellular Components ◽  
Mitochondrial Reticulum

Within the past decade it has become apparent that HVEM offers the biologist a means to explore the three-dimensional structure of cells and/or organelles. Stereo-imaging of thick sections (e.g. 0.25-10 μm) not only reveals anatomical features of cellular components, but also reduces errors of interpretation associated with overlap of structures seen in thick sections. Concomitant with stereo-imaging techniques conventional serial Sectioning methods developed with thin sections have been adopted to serial thick sections (≥ 0.25 μm). Three-dimensional reconstructions of the chondriome of several species of trypanosomatid flagellates have been made from tracings of mitochondrial profiles on cellulose acetate sheets. The sheets are flooded with acetone, gluing them together, and the model sawed from the composite and redrawn.The extensive mitochondrial reticulum can be seen in consecutive thick sections of (0.25 μm thick) Crithidia fasciculata (Figs. 1-2). Profiles of the mitochondrion are distinguishable from the anterior apex of the cell (small arrow, Fig. 1) to the posterior pole (small arrow, Fig. 2).

Building Research Teams

2017 ◽  
Author(s):  
Ken Peach
Keyword(s):  
Common Goal ◽  
Research Teams ◽  
Building Research ◽  
The Past ◽  
Collective Activity ◽  
Research Administrators ◽  
Working Together ◽  
Common Goals ◽  
Almost All ◽  
Century Science

This chapter discusses the process of building research teams. Increasingly over the past three-quarters of a century, science has become a collective activity, with teams of tens, hundreds or even thousands of scientists, engineers and technicians working together on a common goal. Consequently, almost all research involves building, motivating and maintaining a research team. Even a theoretical group is likely to have one or two postdocs, graduate students and visitors, but research teams will, in addition, have engineers and technicians, as well as, possibly, research administrators. The chapter also addresses the importance of creating and maintaining a good team and team spirit, as large projects are assembled from a large number of small teams working on common goals, usually in a loose federated structure with some overall coordination and leadership.

scholarly journals Vibration characteristics of triple-gear-rotor system in compressed air energy storage under variable torque load

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042098705
Author(s):  
Xinran Wang ◽  
Yangli Zhu ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xuehui Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
Rotor System ◽  
Dynamic Responses ◽  
System Response ◽  
Rotating Speed ◽  
Torque Load ◽  
Set Up ◽  
Two Stages

This paper focuses on the effects of the off-design operation of CAES on the dynamic characteristics of the triple-gear-rotor system. A finite element model of the system is set up with unbalanced excitations, torque load excitations, and backlash which lead to variations of tooth contact status. An experiment is carried out to verify the accuracy of the mathematical model. The results show that when the system is subjected to large-scale torque load lifting at a high rotating speed, it has two stages of relatively strong periodicity when the torque load is light, and of chaotic when the torque load is heavy, with the transition between the two states being relatively quick and violent. The analysis of the three-dimensional acceleration spectrum and the meshing force shows that the variation in the meshing state and the fluctuation of the meshing force is the basic reasons for the variation in the system response with the torque load. In addition, the three rotors in the triple-gear-rotor system studied show a strong similarity in the meshing states and meshing force fluctuations, which result in the similarity in the dynamic responses of the three rotors.

Optimum Design for the Frame of Open Type Abrasive Flow Polish Machine

2012 ◽  
Vol 497 ◽  
pp. 89-93
Author(s):  
Liang Liang Yuan ◽  
Ke Hua Zhang ◽  
Li Min
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Finite Element Methods ◽  
Optimization Design ◽  
Low Cost ◽  
Three Dimensional ◽  
Force Model ◽  
Optimization Analysis ◽  
Open Type ◽  
Set Up

In order to process heterotype hole of workpiece precisely, an open abrasive flow polish machine is designed, and the optimization design of machine frame is done for low cost. Firstly, basing on the parameters designed with traditional ways, three-dimensional force model is set up with the soft of SolidWorks. Secondly, the statics and modal analysis for machine body have been done in Finite element methods (FEM), and then the optimization analysis of machine frame has been done. At last, the model of rebuild machine frame has been built. Result shows that the deformation angle value of machine frame increased from 0.72′ to 1.001′, the natural frequency of the machine decreased from 75.549 Hz to 62.262 Hz, the weight of machine decreased by 74.178 Kg after optimization. It meets the strength, stiffness and angel stiffness requirement of machine, reduces the weight and cost of machine.

scholarly journals Personal Carbon Trading—Lost in the Policy Primeval Soup?

2021 ◽  
Vol 13 (8) ◽  
pp. 4592
Author(s):  
Fabio Bothner
Keyword(s):  
Ghg Emissions ◽  
Emission Trading ◽  
Political Agenda ◽  
Carbon Trading ◽  
Multiple Streams ◽  
Policy Proposal ◽  
The Past ◽  
Multiple Streams Approach ◽  
Carbon Taxation ◽  
Set Up

The number of emission trading and carbon taxation schemes implemented has grown rapidly over the past decade. Together, they cover approximately 16% of global greenhouse gas (GHG) emissions. Although more than two-thirds of global GHG emissions are related to household consumption, approaches that directly target households, such as personal carbon trading (PCT), do not play a role in the fight against climate change. This is especially puzzling as measures taken so far are not sufficient to reach the 2 °C target. One clue to solving this puzzle comes from political science in the form of the multiple streams approach, which defines criteria that a policy proposal must meet to become part of the political agenda. Based on these criteria, this article conducts a systematic review on PCT to clarify why PCT does not play a role in the reduction of GHG emissions. The results show that there are three main problems with the PCT proposal. First, scholars often criticize the set-up costs as well as the running costs of such a system. Second, there is no clear consensus within the research community on public acceptance of PCT. Third, it is still unclear whether politicians are receptive to PCT or not.

scholarly journals Midface Reconstruction: Planning and Outcome

2020 ◽  
Vol 53 (03) ◽  
pp. 324-334
Author(s):  
Gautam Biswas
Keyword(s):  
Digital Imaging ◽  
3D Structure ◽  
Three Dimensional ◽  
The Past ◽  
Complex Anatomy ◽  
Osseointegrated Implants ◽  
Low Profile ◽  
3D Printed ◽  
Midface Reconstruction ◽  
Reconstruction Planning

Abstract Reconstruction of the complex anatomy and aesthetics of the midface is often a challenge. A careful understanding of this three-dimensional (3D) structure is necessary. Anticipating the extent of excision and its planning following oncological resections is critical.In the past over two decades, with the advances in microsurgical procedures, contributions toward the reconstruction of this area have generated interest. Planning using digital imaging, 3D printed models, osseointegrated implants, and low-profile plates, has favorably impacted the outcome. However, there are still controversies in the management: to use single composite tissues versus multiple tissues; implants versus autografts; vascularized versus nonvascularized bone; prosthesis versus reconstruction.This article explores the present available options in maxillary reconstruction and outlines the approach in the management garnered from past publications and experiences.

scholarly journals The Study of Three-Dimensional Fingerprint Recognition in Cultural Heritage

2021 ◽  
Vol 14 (4) ◽  
pp. 1-20
Author(s):  
Dzemila Sero ◽  
Isabelle Garachon ◽  
Erma Hermens ◽  
Robert Van Liere ◽  
Kees Joost Batenburg
Keyword(s):  
Image Processing ◽  
Cultural Heritage ◽  
Three Dimensional ◽  
Fingerprint Recognition ◽  
Person Identification ◽  
Imaging Technologies ◽  
The Past ◽  
Reconstruction Methods ◽  
Cultural Systems ◽  
Digital Fingerprint

Fingerprints play a central role in any field where person identification is required. In forensics and biometrics, three-dimensional fingerprint-based imaging technologies, and corresponding recognition methods, have been vastly investigated. In cultural heritage, preliminary studies provide evidence that the three-dimensional impressions left on objects from the past (ancient fingerprints) are of paramount relevance to understand the socio-cultural systems of former societies, to possibly identify a single producer of multiple potteries, and to authenticate the artist of a sculpture. These findings suggest that the study of ancient fingerprints can be further investigated and open new avenues of research. However, the potential for capturing and analyzing ancient fingerprints is still largely unexplored in the context of cultural heritage research. In fact, most of the existing studies have focused on plane fingerprint representations and commercial software for image processing. Our aim is to outline the opportunities and challenges of digital fingerprint recognition in answering a range of questions in cultural heritage research. Therefore, we summarize the fingerprint-based imaging technologies, reconstruction methods, and analyses used in biometrics that could be beneficial to the study of ancient fingerprints in cultural heritage. In addition, we analyze the works conducted on ancient fingerprints from potteries and ceramic/fired clay sculptures. We conclude with a discussion on the open challenges and future works that could initiate novel strategies for ancient fingerprint acquisition, digitization, and processing within the cultural heritage community.

scholarly journals Computer-aided design of multi-purpose steel headframes for mines with a new technical level

2020 ◽  
Vol 174 ◽  
pp. 01048
Author(s):  
Elena Kassikhina ◽  
Vladimir Pershin ◽  
Nina Rusakova
Keyword(s):  
Cross Sections ◽  
Computer Aided Design ◽  
Information Technologies ◽  
Three Dimensional ◽  
Numerical Control ◽  
Technical Level ◽  
Resource Saving ◽  
Existing Structures ◽  
Set Up ◽  
Aided Design

The existing structures of the steel sinking headgear and permanent headframe do not meet the requirements of resource saving (metal consumption and manpower input at installation), and the present methods of the headframe designing do not fully reflect recent possibilities of applying of the advanced information technologies. Technical level of the modern software makes it possible for designers to set up multiple numerical experiments to create a computer simulation that allows solving the problem without field and laboratory experiments, and therefore without special costs. In this regard, a mathematical simulation has been developed and based on it, software to select cross-sections of multi- purpose steel headframe elements and to calculate proper weight of its metal structures depending on the characteristics and hoisting equipment. A headframe drawing is displayed, as the results of the software work, including list of elements, obtained optimal hoisting equipment in accordance with the initial data. The software allows speeding up graphic work and reducing manpower input on calculations and paper work. The software allows developing a three-dimensional image of the structure and its functional blocks, based on the obtained initial parameters, as well as developing control software for units with numerical control (NC) in order to manufacture multi-purpose headframes.

Design and Marker-Based Validation of a Biplane Fluoroscopy System for Studying the Foot and Ankle

2012 ◽  
Author(s):  
Joseph M. Iaquinto ◽  
Richard Tsai ◽  
Michael J. Fassbind ◽  
David R. Haynor ◽  
Bruce J. Sangeorzan ◽  
...  
Keyword(s):  
Precise Measurement ◽  
Three Dimensional ◽  
The Body ◽  
Initial Evaluation ◽  
Foot And Ankle ◽  
Research Groups ◽  
The Past ◽  
Model Based ◽  
Biplane Fluoroscopy ◽  
Model Based Analysis

The ability to accurately measure three dimensional (3D) bone kinematics is key to understanding the motion of the joints of the body, and how such motion is altered by injury, disease, and treatment. Precise measurement of such kinematics is technically challenging. Biplane fluoroscopy is ideally suited to measure bone motion. Such systems have been developed in the past for both radiographic stereo-photogrammetric analysis (RSA) [1] and the more challenging model-based analysis [2]. Research groups have studied the knee [3,4], shoulder [5] and ankle [6] motion with similar techniques. The work presented here is an initial evaluation of the performance of our system, i.e., a validation that this in-house system can detect magnitudes of motion on-par with other existing systems.

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